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Development of user customized smart keyboard using Smart Product Design-Finite Element Analysis Process in the Internet of Things
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Research article
Development of user customized smart keyboard using Smart Product Design-Finite Element Analysis Process in the Internet of Things Jung Woo Kim, Sang Hun Sul, Jae Boong Choi∗ Department of Mechanical Engineering, SungKyunkwan University, Suwon-si, Gyeonggi-Do, Seobu, Ro2066, Republic of Korea
A R T I C LE I N FO
A B S T R A C T
Keywords: User customized smart keyboard Smart product design-finite element analysis process (SPD-FEAP) Smart quality function deployment (SQFD) using WebData 3D Shape analysis by finite element analysis (FEA)
In a hyper-connected society, IoT environment, markets are rapidly changing as smartphones penetrate global market. As smartphones are applied to various digital media, development of a novel smart product is required. In this paper, a Smart Product Design-Finite Element Analysis Process (SPD-FEAP) is developed to adopt fastchanging tends and user requirements that can be visually verified. The user requirements are derived and quantitatively evaluated from Smart Quality Function Deployment (SQFD) using WebData. Then the usage scenarios are created according to the priority of the functions derived from SQFD. 3D shape analysis by Finite Element Analysis (FEA) was conducted and printed out through Rapid Prototyping (RP) technology to identify any possible errors. Thus, a User Customized Smart Keyboard has been developed using SPD-FEAP.
1. Introduction Starting from 2009, smartphones have spread rapidly in the domestic market and its market share has been rising and accelerating [1]. Smartphone is experiencing a rapid growth due to its mobility, accessibility, expandability, convenience and multi-tasking. Due to the rapid expansion of Internets in 2010, high-end smartphones were developed, starting the era of Hyper-Connectivity [2]. Anabel Q. Haase and B. Wellman predicted the formation of networks in hyper-connected society would have significant impacts on the everyday lives of people [3]. New technologies were developed recently as various sensors and communication technologies are mounted on various things such as home appliances, mobile phones and wearable computers [4]. Xiaosong Hu et al. applied Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) technologies of Cyber Physical System to seek improvements in fuel efficiency by optimal control [5]. Therefore, a concrete plan and clarification of the environment on the implementation of Cyber Physical System and V2V, V2I communication must be explained in a detailed manner. It is Machine-to-Machine communication (M2M) [6–8] which controls the surrounding environment to enable each and every objects' intercommunication using sensors. M2M offers users with information that are autonomously generated from data which has been collected, shared, analyzed, and learned by internet-connected-objects [9]. Due to expeditious development in Information Technology (IT) the convenience-offering next-generation mobile communication service were highlighted. With this and the development of Internet of Things (IoT) [10,11] technology, various ∗
connection methods between people are being spread. Smartphones constructed groups that are connected via various methods such as messenger, email, and video connection [12]. As the newly connected networks [13] enabled the users with desired functions and characteristics, the purchase decision factors for smartphones have been modified [14,15]. As numerous functions were added to smartphones, recent user purchasing trends has also been shifted to shorter product life cycle and faster purchase rate. Digitime Research estimated worldwide smartphone shipments will grow 7.2% year-onyear to 1.22 billion dollars in 2016, and another 7.0% year-on-year growth to record 1.52 billion dollars in 2017 [16,17]. The keen and universal competition in smartphone industries experienced sharp increase in total sales as cutting-edge technologies such as quick charging, optical image stabilized (OIS) camera, Touch ID, etc. It is also expected that in 2019, more than 7.6 billion of the worldwide population will own smartphones due to the growth of smartphone market and production of various smartphones [18]. Users exhibited a new trend of improved utilization while connecting wireless networks regardless of time and space. The development was observed not only to smartphones where wireless networks were established all the time in IoT environment, but also to smart devices with same operating system (OS) as smartphones such as smart pads, tablet PCs, and smart TVs [19]. Smart devices [20] are now leading the global mobile market and the penetration and growth rate is on the sharp increase as they offer wide range of applications and share new information [21,22]. Recent trends show that users began to utilize converged products
Corresponding author. E-mail address: [email protected] (J.B. Choi).
https://doi.org/10.1016/j.isatra.2018.05.010 Received 12 January 2018; Received in revised form 30 April 2018; Accepted 14 May 2018 0019-0578/ © 2018 ISA. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Kim, J.W., ISA Transactions (2018), https://doi.org/10.1016/j.isatra.2018.05.010
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User requirements evaluation organizes the data quantitatively and qualitatively to be applied to the actual environment. This reduces the time taken during the designing process for smart products and analyzes any expected defects in advance using Computer Aided Design (CAD) [39–41] data for evaluation. When developing the smart product, actual usage environment of the product is taken into account to apply Finite Element Analysis (FEA) [42–46], where the morphology and boundary conditions are unlimited. During 3D shape analysis by Finite Element Analysis (FEA), additional process such as selection of appropriate thickness suitable for the designed structure, examination of formability and structural reliability to minimize problems that might occur due to external deforming factors. Simulation is done so that Users can be visually informed of the process to improve the reliability of the smart product and its developmental process. Mock-up output is printed and examined to obtain both quantitative and qualitative data for verifying accuracy and optimize morphology, and to apply Rapid Prototyping (RP) technology [47–50] for minimum modification. This process not only simplifies and complements the design by user's evaluation through RP technology, but also improves the reliability of the smart product by adopting appropriate material to ensure sufficient wear resistance. Also, by constructing a working mock-up, the internal cooling structure and the painting operation of the printing section are performed. By printing and using the smart product as a mock-up, user's evaluation is done to analyze performance error, faulty elements so that a prototype is derived similar to that of mass products at a developmental stage. Since it is possible to acquire reliability from designing to massmanufacturing, achieve shorter development period and reduce costs through these processes, it is expected that the process would gain a competitive edge within the smart product market.
adopting digital system that links smartphones to smart devices. Smart products reflect developments of hardware and software platforms based on IoT, firmware planning and various core technologies related to IoT devices [23]. Although continuous revisions of smart products [24] based on the users' requirements are vital aspect of smart product development, existing products have difficulties in their immediate revisions due to their integrated manufacturing process. As revision process for products to adopt new ideas is diversifying, high cost of mold designing and long production period became a major hindrance in product development [25,26]. In mold design process in the fields, this manufacturing method relies mostly on experienced developers rather than reflecting the users' requirement in the mold design stage in the field. Thus, this causes dimensional errors, complicated design processes, and time-consuming operations for mass production. Thus, the manufacturing processes are experiencing a transition to modular manufacturing process in order to instantly reflect users' requirements. Subjects related to smart products, which are suitable for modular manufacturing, are being studied to systemize and modify 3D image output from 2D image, minimize residual stress, and optimize molding condition for maintain precision for performance. To develop a smart product that is suitable for modular manufacturing, intensive research efforts are underway, like systematizing the output, modification, and supplementation of 2D images into 3D shape, minimizing the residual stress formed in the product during design verification, and optimizing the molding condition [27,28]. Emerging trends show that the products' life cycle [29–32] is shortening. However, products' quality evaluation and verification for smart products are yet to be researched. Thus, a novel method of development for smart products is required so that User Experience Design (UX) [33–35] is taken into consideration. Goedkoop et al. introduced Product Service System (PSS) as a user-centric design process [36]. Although PSS is used to satisfy the users' requirements, there are limitations to develop appropriate products for ongoing trends. Joseph T. Emanuel and Dennis E. Kroll [37] proposed a systematic approach to product designing and processing that can be drawn simultaneously. In order to produce smart products that users want, emphasis must be put on the importance in design, reliability of performance and practicality during the manufacturing process [38]. Therefore, a simple, convenient, mass customized Smart Product Design-Finite Element Analysis Process (SPD-FEA) is developed. In this paper, a User Customized Smart Keyboard that meets the underlying trend in hyper-connected society has been developed using SPD-FEAP. This process quantitatively analyzes users' requirements from Smart Quality Function Deployment (SQFD) using WebData. Information such as preferences to products, usage patterns, and lifestyles are comprehensively considered to determine the concept. As a quantitative analysis method, Usage scenario with storytelling are adopted in order to enhance the degree of comprehensibility so that functions, figure, sizes would reflect the actual product usage environment to formulate product's specification.
2. Development of Smart Product Design-Finite Element Analysis Process (SPD-FEAP) In a hyper-connected society, IoT-based environment, the usage of smart products is changing rapidly due to varying lifestyles of the users and their activeness in sharing and competing online. Although the demand for smart products is experiencing a sharp increase according to current, fast-changing trend, there exist difficulties in developing a smart product with user requirements reflected. The trend for manufacturing products has also influenced method of manufacturing, thus experiencing a shift from mass production to mass customization. As converged technologies are applied to the products, the developmental period is shortening from simply developing hardware and software to developing high quality products for enhanced precision for performance. A novel design process that can continuously acquire users' requirements and analyze requisite of products and thus adopt to current fast-changing trends in hyper-connected society. To adopt a different view from technology-intensive manufacturing,
Fig. 1. Smart product design-finite element analysis process (SPD-FEAP). 2
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3. Verification of Smart Product Design-Finite Element Analysis Process (SPD-FEAP)
a User Customized Smart Keyboard has been developed with SPD-FEAP as shown in Fig. 1. In order to derive a desired quantitative analysis from big data, wide range of consumers' comments are collected to analyze their interests and trends per period. Keywords are derived from latest market trends and studied using Google Trend offered by Google and Amazon websites for international trends, Naver Trend and their blogs offered by Naver for domestic market. These users' requirements are extracted from non-structured data, which are rapidly increasing online in hyper-connected society, and applied SQFD to structuralize the data. In developing a smart product, SQFD using WebData is conducted on users' requirements that were extracted for quantitative evaluation. During this analysis, the information is classified into various categories such as products' preferences, usage patterns and lifestyles. In manufacturing a smart product, critical parts and components are identified and arranged as scoring system so that each parts can be analyzed in terms of importance and user satisfaction. Also, keywords that offers users with optimal UX have been extracted and analyzed their data patterns through quantitative evaluation so that the smart products can be actualized. When establishing basic concepts and design phases in developing smart products, all steps can be systematically connected to identify feasible problems, design considerations, thus reducing the change of design. Taking the users' purchasing patterns and lifestyles including information such as sex, age and occupation into account, smart products reflect users' emotional elements in usage scenario with storytelling for qualitative evaluation. Also the material property and their texture difference due to the existence of glossiness verified in terms of emotional aspects. As a result, reflecting fun elements, users' understanding of the product was improved while the core elements for the development that suits the trend were derived and applied to actual functions. 3D shape analysis by FEA was conducted in virtual space to analyze elements that cannot be done in real-life tests to visualize the user's evaluation results. Thus anticipating errors regarding precision of performance during the design process. Product's strength, stress analysis and material property has been chosen to meet the users' requirements. 3D shape analysis by FEA was conducted according to the users' requirements to visually confirm and discover any problems of the smart product at an early stage. Also the reliability of the prototype was improved by anticipating their performance and verifying safety and presence of defects. Adopting fast-changing and trend-sensitive users' requirements to smart products requires RP so that important elements such as accuracy of data, swift development and reliability are satisfied. By minimizing the required process in complicated product designing, RP enables the smart product to be verified not only in developmental stage but also in mass production. A life-size prototype has been made according to the design blueprint that has been modified with colors, shapes, impressions, etc. Also, a working mock-up where internal parts can be linked each other was printed out to examine any drawbacks to performance. From this, the unnecessary costs of time and resource for mold designing and mass production are reduced to minimum during the user's evaluation. Moreover, the users' requirements can be reflected instantly and conveniently in the evaluation, not only it can reduce the costs for mass production. A life-size prototype has been made according to the design blueprint that has been modified with colors, shapes, impressions, etc. Also, a working mock-up where internal parts can be linked each other was printed out to examine any drawbacks to performance. From this, the unnecessary costs of time and resource for mold designing and mass production are reduced to minimum during the user's evaluation. Moreover, the users' requirements can be reflected instantly and conveniently in the evaluation, not only it can reduce the costs for mass production.
User requirements are critical aspect in analyzing the current trends of newly developed products and they are applied to SQFD with measured weights in the order of priority. The process thereby results in the improvements of the product. Data related with user requirements are used to derive necessary aspects of the products in a quantitative methodology. Also, usage scenario with storytelling for qualitative evaluation are made so that users can easily apply them during the actual usage. A user evaluation has been conducted to understand the critical functions and problems of the product. Based on this evaluation, an idea sketch, 2D sketch and 3D modeling were done. Through this series of evaluations, the convenience, usability and feasibility of the detachable design are verified. Lastly, a Finite Element Analysis (FEA) is applied to 3D modelled object to examine the mechanical reliability and safety of the product. 3.1. Quantitative evaluation method for smart product development Unstructured data is increasing with the spread in the use of Internet-based Social Network Service (SNS) that can confirm recent trends. In order to grasp the user requirements, passive data were extracted at the stage of WebData. We watched over the representative online sites, Google (www.google.com) and Naver (www.naver.com). Then the SQFD was applied which works as storage, management, and analysis of the user requirements through trend analysis and user comments, and reviews of products. The correlation between extracted WebData and functions that were prioritized were derived. These improvement points serves as methods for implementing new functions, and confirmed the problem. Fig. 2 shows that the user requirements extracted from online WebData of Google and Naver were derived through quantitative analysis by measuring their weights in the order of priority. The higher the word frequency, the more important the keywords that were extracted according to the frequency of similar words, and summarized. Frequency grasped specific words of user requirements were used to determine their importance. Weight is given to keywords according to the extent of analysis and the evaluation shown in sentences. As a result, SQFD organizes the horizontal axis as user requirements, and the vertical axis denotes desired functions according to user requirements. Fig. 3 shows that important elements of the product are derived according to the user requirements through SQFD, and the communication method, product shape, and product material are organized. The Bluetooth technology, which is a current dominating wireless communication technology, is on the steady rise. However, the reaction time increases as the communication range increases, and the fact that it consumes additional smartphone power source without batteries inside the smart product, a separate measure was to be applied. In order to solve this, USB standard functions USB On-The-Go (OTG) is adopted to be used as a communication method. With the increased development of various interface devices, it is effective to reduce weight and capacity by installing USB OTG into a very thin outer shape design. In addition, charging terminals of smartphones can be wired to be compatible with external I/O devices, and the inconveniences of battery replacement can be minimized. As a product form, we considered a method of simply placing a smartphone using a straight line-centered design. Considering the mobility to be used, we pursued a stable coupling system by designing a jaw that prevents the smartphone from detaching. Also, we used USB OTG to minimize the smart product weight burden, and to use the smartphone battery power. The pattern touch interface in which the user operates the smart product was considered, to enhance usability. The material of the product can express various colors, and liked the apparent material with plastic excellent in mold ability. On the top of the product, based on user requirements, we chose a removable 3
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Fig. 2. Quantitative analysis of Smart Quality Function Deployment (SQFD).
smartphone and floor to prevent shaking. Applying a rubber that can grip onto the top end of the smartphone prevented it from slipping. Considering the usage environment, we improved the reliability of the product by considering its durability, wear resistance design, and life waterproof design. We applied sensitive parts, such as communication method, product form, and product material, as necessary elements for developing smart products. Table 1 shows the result of deriving user requirements based
on the priority in correlation with smart quality function development applying big data, systematized for qualitative evaluation. 3.2. Qualitative evaluation method for the analysis of the actual functions We conducted qualitative evaluation to naturally induce the participation of users who are influenced by the trend of the hyper connected society. Using the data of user requirements derived with
Fig. 3. SQFD as essential function of User Customized Smart Keyboard. 4
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3.3. 3D modeling design visualization for user evaluation
Table 1 User requirement analysis to developing User Customized Smart Keyboard. User requirement
Result
1 2
If you can easily separate the smartphone and the keyboard If you have a sense of grip that makes it easy to pick up the keyboard design If the portability is good with a structure easy to use anytime and anywhere If the font of the keypad is printed cleanly and there is no difficulty finding characters If there is less input error than the touch keyboard and you increase the accuracy When the use time increases compared to the charging time
3 4 5 6
Three user requirements that summarize usage scenarios are proceeded at the design stage. We evaluated the user using idea sketch, 2D sketch, and 3D modeling, so that we could actually visualize the product. Design verification that emphasizes ease of use and convenience is necessary, so that smartphones can be attached and detached. Smart product design analyzes the problem expected when using it in an actual environment by FEA, and confirms its validity. RP was applied at the mock-up stage of the product and the working mock-up designed, after the user's evaluation of the final 3D design. We can visually express the problems that can exist, rather than simply describing the product as it is at the stage of idea design sketch. In order to develop the form of a new design, we emphasize the shape of the stereoscopic design according to the perspective technique, the pen sketch technique that exploits the relationship between shades and the line expressed by different thicknesses. In order to visualize the user requirements implemented in the usage scenario, we developed the design by adding colors to reflect smart product sketches. Application of the usage scenario to the UX and the environment expresses various post processing and text on materials for the required design. As a result, the user requirements was reflected, and idea sketches A, B, and C made it easy to understand not only for the unique design, but also to derive suitability for use. Fig. 5 shows an idea sketch of a type based on ergonomics that a user can adapt easily in everyday life. It is a concept design that can attach and detach various types of smartphones with adhesive pads, with a built-in silicone type keypad. The human-centered idea sketch B type provides users with a new experience. A single PCB and a keypad are built into a thin plate material, and the design under which the protruding face under the second half of the keyboard is connected with the smartphone to emphasize the grip feeling. The idea sketch C type can be customized according to the personality of the user. It is a concept design composed of a connection terminal and a cover that supports the back of the smartphone with a folding structure, considering the portability. The idea design sketch designs CAD data using 2D CAD, such as points, lines, planes and graphic symbols for the visual user requirements organized at the stage. It is possible to easily reflect the drawing by changing the precise dimensions. Design 3D modeling allows the interference of parts to be checked at the stage of modeling, problems with the assembly, and design elements with the silicon type keypad built using Inventor v.15.0, which is a 3D design program.
applying the storytelling use scenario, it was complemented to develop smart products. Based on the UX, we can interact with each other at all development stages by user participation, use, and observation. We arrange in order of high evaluation among user requirements derived by correlation and extract contents of rank 1 to 3. In the early stages of development, we consider user profiles, preferred functions, and applicable product functions. From the user point-of-view, we set the purpose of use and duration of use of the product virtually, and describe it based on six principles to facilitate fundamental understanding of the product. Derivation of new functions for product design and product concept can be organized based on user requirements, and errors can be minimized. Fig. 4 shows that we derive qualitatively for User Customized Smart Keyboard development based on the creation of a usage scenarios. We determined priorities by considering the functions and problems actually required by the based on user requirements derived from important keywords through SQFD, we created a usage scenario to create empathy associated with lifestyle. By presenting the usage scenario in the form of a story in a qualitative way to easily convey the contents to the user with important keywords, it is possible to enhance the degree of understanding of the product. We applied the user requirements to the actual lifestyle to derive a simple attachment and detachment method, a design with excellent grip feeling, and portability and simple structure. By defining functions and specifications suitable for improving the ease of use necessary for the development of smart products in the use scenario based on the storytelling executed at the planning stage, we were able to design an ergonomic smart product.
Fig. 4. Test usage scenario applying storytelling for qualitative evaluation. 5
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Fig. 5. Idea sketches applying three functions of User Customized Smart Keyboard.
Fig. 6. User Customized Smart Keyboard of 3D modeling shape reflecting user requirement.
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Fig. 7. Design condition and boundary condition for the analysis of User Customized Smart Keyboard. Table 2 Design condition of User Customized Smart Keyboard for FEA. No
Case name
L (mm)
Lpad (mm)
Lkey (mm)
W (g)
Tpad (mm)
1 2 3 4 5 6
A-1 A-2 B-1 B-2 C-1 C-2
135 135 81 81 109.7 99.56
75 75 75 75 50.14 40
60 60 60 60 59.56 59.56
65 65 67 67 65.2 65.2
3.5 1.6 3.1 3.1 1.6 1.6
By evaluating the user requirements so that the PCB and the keypad are built in a thin plate material, the projected design below and the design of the folding structure considering portability can be visually confirmed. Fig. 6 shows the 3D modeling shape based on CAD data. This enables the appearance of the design to be examined and the function of the product to be considered. The synthesis of the type of design to be studied, the hardware design to be checked along with water mount ability considerations, etc. Also, design errors can be prevented, and correction work can be done in advance. This reflects the user
Fig. 9. Von mises visual results of finite element analysis for user's evaluation.
requirements at the User Customized Smart Keyboard 3D modeling design stage. In advance, we analyzed all problems expected in the mock-up, working mock-up, and final model production process and
Fig. 8. User customized Smart Keyboard models as Finite element analysis users Evaluation. 7
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Fig. 10. User Customized Smart Keyboard reflecting user requirements A, B, and C models.
suitable for the structure, consider the formability and influence factors of appearance deformation. We could evaluate users by using 3D shape analysis by FEA of the design and development of smart products. By reducing the process of repetition and correction of preview, it is possible to shorten the development period, improve quality and reduce costs. Fig. 7 shows that the loading conditions are shown in red for the conditions used for FEA, and certain conditions were displayed in black, so that the user could easily understand the design visually. The weight of the smartphone is 158 g on average, designating it as a boundary condition, handling of the back of the keyboard of the smartphone, and considering certain conditions. In order to check the overall stress of the product, the detailed mesh setting was set to Hex Dominant using automesh. As loading conditions, mechanical loading was considered. Generally, when the user uses a keyboard, the pressure required is about 50 g. Thus it is expected about 60 g force in touching each keypads and assumed so. With the same material as the 3D printed material in the actual usage environment, the User Customized Smartphone Keyboard material advanced analysis used polycarbonate EH-1050. Selected for analysis conditions, EH-1050 polycarbonate is a resin product with one kind of thermoplastic resin, resin layer in glass fiber layer. As a result, characteristics such as impact resistance, durability, heat resistance, weather resistance, self-miniaturization and transparency were taken into consideration. As a result, detailed design condition of the model made into the 3D shape of the six models of the User Customized Smart Keyboard, so that it can be combined with the smartphone presented as shown in Table 2. Where, L is the User Customized Smart Keyboard length and pad length, Lpad the User Customized Smart Keyboard pad length, Lkey the
Table 3 Improved design condition of User Customized Smart Keyboard for FEA. No
Case name
L (mm)
Lpad (mm)
Lkey (mm)
W (g)
Tpad (mm)
1 2 3
A B C
135 135 125.77
75.5 75 72.41
59.5 60 53.36
65 67 65
3.0 3.1 2
proceeded with user's evaluation to obtain the optimum design data. In accordance with the user requirements, we derived six models based on designs that marked the highest user ratings. Each models have different designs by built-in silicon type keypad, PCB on thin board material, extruded design under, and folding structure considering portability. By applying it to a series of several composite materials, we could apply FEA that can be utilized in all fields. The design was confirmed without restrictions, such as geometrical shape, load, and boundary conditions using 3D shape analysis by FEA. 3.4. 3D shape analysis of user customized smart keyboard by finite element analysis (FEA) 3D shape analysis by FEA the smart product design could be improved and modified according to user requirements for shape analysis. The accuracy could be increased by enlarging the mesh size of the smart product and the number of elements, and grasping the possibilities of actual products. In order to evaluate the strength, we could check the maximum stress and deformation amount, while applying the results to the user's evaluation of the smart product in a similar manner. Also, we could check the mechanical reliability through FEA and confirm it to improve product safety. We could determine the selection of thickness 8
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Fig. 11. Results of User Customized Smart Keyboard A, B, and C models via FEA.
models. Using the model of the User Customized Smart Keyboard, we analyzed any possible errors that can occur in the actual environment. Fig. 8 shows that the FEA was confirmed by six models according to user requirements. In the Lpad part of the A-1 model, a horizontal stress distribution occurred. The model of A-2 confirmed that the stress was intensively distributed on both sides of Lpad, with the curved surface Lpad shape supporting the smartphone. The types of stress concentration phenomena occurring of B-1 are almost the same and the stress concentration phenomenon displayed by the B-1 model appears more widely distributed than that of the B-2 model. In C type with Lpad length shorter than for A and B, model, we confirmed the overall stress distribution phenomenon in the Lpad part. In the C-1 model, the Lpad method was designed as a slide type, and a high stress concentration phenomenon occurred at the connection part. In the C-2 model, high stress concentration phenomenon was confirmed in the Lpad and Lkey parts. The FEA was used to develop smart products that reflect the user requirements for A, B and C models. For A, B, and C models, the Lpad part where smartphones and keyboards adjoin showed greatest stress concentration. Fig. 9 shows the visual results obtained by performing FEA on six models of the User Customized Smart Keyboard reflecting the user requirements, which are summarized in a graph for user's evaluation. For the A-2, C-1, and C-2 models located above the von mises stress of 2.5 × 106 pa, the structural features by user requirements were taken into consideration. In the case of the B-2 model, the positions A-1 and B1, which are below the average, have a low probability of failure and a stable structure. In the primary evaluation, the user has confirmed the necessary models. Fig. 10 shows the comparisons between A-1 and A-2 models, which are the designs that reflect user requirements, where small stress
Fig. 12. Visual result of improved von mises for finite element analysis for user evaluation.
User Customized Smart Keyboard length, W is the User Customized Smart Keyboard weight and Tpad is the thickness of the keyboard of the smartphone. We derive the visual results of the FEA from the user's evaluation and consider the User Customized Smart Keyboard. We investigate failure cause beforehand, to confirm mechanical problems in the design. As a result, by searching for a solution, errors in precision of performance are minimized in the course of additional improvement work. FEA confirmed the stress distribution and stress concentration of smart products using Ansys ver.18 workbench, a commercially available structural analysis program. We confirmed with 6 full models as 3D FEA 9
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Fig. 13. User customized smart keyboard mock-up extracted by Rapid Prototyping.
Fig. 14. Derived user customized smart keyboard A model.
4. Application of Smart Product Design-Finite Element Analysis Process (SPD-FEAP)
concentration was identified. In the case of the C-1 and C-2 models, the high stress concentration phenomenon was grasped in the Lpad and Lkey parts in the C model with improved cover type with slide shape. The results of the FEA of six models of the User Customized Smart Keyboard showed that considerable stress concentration phenomenon occurred between the keypad and keyboard. In order to improve this, FEA of the advanced design condition of the model was conducted for three design supplemented models. These improved models are shown in Table 3. We proposed three FEA s by deriving three 3D modeling reflecting the user requirements in the User Customized Smart Keyboard, which was complemented through user's evaluation. Fig. 11 shows the User Customized Smart Keyboard that joins the smartphones predicted the possibility of the thickness of the Lpad surface being damaged, depending on the amount of deformation of the product. We also confirmed that the back side of the User Customized Smart Keyboard has an influence on the deformation volume. During the user's evaluation, the User Customized Smart Keyboard A was chosen since it emphasized portability and convenience showed that horizontal stress distribution occurred, compared with the two models of the Lpad part. Through the secondary evaluation, we proceeded to FEA of three models of the User Customized Smart Keyboard reflecting user requirements, as shown in Fig. 12. Based on the von Mises stress of 2.5 × 106 pa, we confirmed that all models A, B and C have high stability as the von Mises stresses of each models were located far below the average that was assumed for the FEA.
Rapid Prototyping technology is applied to create a prototype of the smart product in order to revise and complement the design blueprint. Finite element analysis of the 3D modelled object enables to check any possible errors of the design in advance. 3 different mock-ups according to the users' requirements are created using RP. Taking UX into consideration, the internal mechanical structure of the product is reviewed and evaluated for possible improvements. As a result, a working mockup of User Customized Smart Keyboard reflecting user requirements and current trends are made in considering the products' reliability and convenience. 4.1. User customized smart keyboard verification for Rapid Prototyping (RP) Continuously reflecting the user requirements in a hyper-connected society, we develop prototypes that can modify and supplement design drawings by applying RP in the development smart products. By developing smart products of various types in small quantity production, they can be produced inexpensively and efficiently, while production efficiency can be secured by shortening the design time. Fig. 13 shows smart products A, B, and C types via RP, with a modified FEA reflecting the user requirements. Visualization and 3D modeling of the keyboard reflecting the users' requirements were determined from the shape analysis. Then, RP was 10
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Fig. 15. User customized smart keyboard rendering image.
Fig. 16. User customized smart keyboard Working Mock-up.
design, before making them into the actual product. In addition, we determined mass productivity, assembly, type synthesis, etc. through mock-up and working mock-up production of smart products that can reflect user requirements repeatedly in the design process to match
conducted to confirm the size, shape and grip feeling of the actual size. One major advantage of adopting RP technology is that it is possible to quickly reflect complementation in the correcting process, by checking the prototypes. This would minimize errors that can occur during 11
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Fig. 17. Operation test of user customized smart keyboard.
writing ‘Hunminjeongeum’. The keyboard was made in two models, which have red and blue color. According to the user requirements, the red model adds glossy color which emphasizes luxury, while the blue model considers refinement.
current trends. While still considering the UX, we designed an optimized design to ensure the wear resistance of the painted and printed parts. By checking and evaluating the internal mechanism, improvements were further made by increasing the performance by confirming the creation, interference, etc. by the combination of each part. Fig. 14 shows an ergonomic design of the User Customized Smart Keyboard based on FEA that was considered. Small type, slim type, folder type and flexible type were devised and designed with an emphasis on portability and detachability. Based on the user's evaluation, we designed the User Customized Smart Keyboard so that when the user grabs the keyboard with both hands, it provides comfort to the wrist. Moreover, convenience of the product was also taken into consideration by minimizing the difficulty of its operation, as it is immature and difficult to operate. We implemented a User Customized Smart Keyboard that minimizes the constraints of activities, without feeling discomfort at the time while using. The UX was applied to ergonomic design to protect the wrist with the same size as the actual product. Fig. 15 shows the consideration of the sensational aspects of the user in the rendered image of the finishing parts that have been confirmed with scale, volume and color of User Customized Smart Keyboard. Then the user's evaluation was conducted on user's perspective to the surface property, volume and texture in User Customized Smart Keyboard.
5. Conclusions In hyper-connected society, as lifestyle patterns based on smartphones have been spread globally, small input screens of smartphones became a hindrance for interaction. In order to tackle this problem, users are increasingly using smart products as converged products as a communication method. Smart products are converged products sensitive to current trends which makes reflecting of user requirements a vital element in development. In this paper, a User Customized Smart Keyboard that meets the underlying trend in hyper-connected society has been developed using SPD-FEAP. Functions that user requirements indicated were derived from SQFD using WebData. The prioritized user requirements that were then put down into various usage scenarios for qualitative analysis. Through this process, a User Customized Smart Keyboard was developed having functions that users actually require the most while associated problems were identified in advance. In order to pre-identify the feasible problems in advance after the user requirements were adopted, user's evaluation was made with 3D shape analysis by FEA. Strength, noise and vibration was taken into consideration during tests for actual usage environment with FEA. As a result, the joint between the smartphones and the User Customized Smart Keyboard showed greatest stress concentration. Strength evaluation was conducted to verify maximum stress, deformation, stress distribution, loading conditions and selection of material to figure out any structural problems from identified fault-causing factors. Three models of User Customized Smart Keyboard that adopted user requirements were conducted with FEA. As a result, it has been confirmed that all models A, B and C showed high stability with 2.5 × 106 pa of von mises stress, located below the average value. In order to visually confirm the FEA results, user's evaluation was conducted with smart products A, B and C by printing out in 3D shape according to the design blueprints. Also, by creating a mock-up, each parts' interference with the assembled shape and assembly tolerance was confirmed. Considering the actual working environment, a working mock-up is then created to verify the smart product's life size, quality and grip feelings. As a result of reflecting user requirements for portability and convenience, the User Customized Smart Keyboard model A
4.2. User customized smart keyboard working mock-up Using the results of the rendered image, we chose the appropriate material for the User Customized Smart Keyboard to ensure abrasion resistance. Fig. 16 shows that modeling for enhancing product reliability was selected. We developed the User Customized Smart Keyboard PCB through execution and development of coding of firmware for USB OTG operation. In terms of functionality, the model was designed to minimize the volume using smartphone batteries, as well as being removable from smartphones in combination with a USB type of User Customized Smart Keyboard. In addition, the optimum design keypad of a circuit that can be driven for a long time constitutes a 20 EA button. In place of the basic 12EA button, we placed an input assistance function key 8EA button that emphasized ease of use for languages, basic 12EA button. The button operation part was designed so that users can feel analog esthetic from digital equipment by implementing a vibration touch interface. We applied a design that can provide detailed operation and input feedback that had been impossible with touch. Fig. 17 shows the operation test of User Customized Smart Keyboard 12
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has been chosen. The user requirements were then visually presented to improve precision to user's evaluation result. User Customized Smart Keyboard was designed as ‘Cheonjiin’ styled 20EA keypad buttons. 12EA buttoned keypad was added for input languages without word spacing and 8EA function buttons for auxiliary inputs emphasizing convenience. At the operating button, vibrational tactile impression interface has been designed to enable users with analog esthetic from digital devices, detailed manipulation, feedbacks from inputs. Utilizing SPD-FEAP as a developing process, it is expected that the quality of the smart products, which are trend-sensitive, will be improved and will minimize the time and cost during the development. Also, the research not only alleviates difficulties in smartphone based communications in an IoT environment, but also to form a whole new market in the Age of Digital Civilization. The current study on SPDFEAP continuously applies converging technologies to react to fastchanging trends. Hereafter researches on the development of IoT-based smart products that can provide customized services are expected to be made.
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Acknowledgments This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B03031469). References [1] Rijsdijk Serge A, Hultink Erik Jan. How Today's consumers perceive Tomorrow's smart products. Prod Dev Manag Assoc 2009(26):24–42. [2] Aducci Romina, Bilderbeek Pim, Brown Holly, Dowling Seana, Freedman Nora, Gantz John, Germanow Abner, Manabe Takashi, Manfrediz Alex, Verma Shalini. The hyperconnected: here they come! IDC. 2008. p. 1–16. [3] Haase Anabel Q, Wellman B. How does the internet affect social capital. In: Huysman M, Volker W, editors. IT and social capital. 2002. p. 1–14. [4] Huang JD, Hsieh HC. Design of gateway for monitoring system in IoT networks. Proceedings of IEEE international conference on green computing and communications (GreenCom) and IEEE internet of things and IEEE cyber. Physical and social computing (iThings/CPSCom). 2013. p. 1876–80. [5] Hu Xiaosong, Wang Hong, Tang Xiaolin. Cyber-physical control for energy-saving Vehicle following with connectivity. IEEE Trans Ind Electron 2017;64(11):8578–87. [6] ETSI. Machine-to-Machine communications (M2M). Funct Arch 2013:1–332. ETSI TS 102 690. (2.1.1). [7] Lucero Sam. Maximizing mobile operator opportunities in M2M. CISCO; 2010. p. 1–19. [8] Raymond Juma W, Olwal Thomas O, Kurien Anish M. Cooperative communications in machine to machine (M2M): solutions. Challenges and future work. IEEE Access 2018;99:1–19. [9] Evans Dave. The internet of things how the next evolution of the internet is changing everything. CISCO; 2011. p. 1–11. [10] Hsieh HC. Design of gateway for monitoring system in IoT networks. Proceedings of IEEE interna. 2013. [11] Ashton Kevin. The internet of things how the next RFID journal 2009. [12] Atzori L, Iera A, Morabito G. The internet of things: a survey. Comput Network 2010;54(1):52787–805. [13] Sarwesh P, Shekar N, Shet V, Chandrasekaran K. Energy efficient and reliable network design to improve lifetime of low power IoT networks. 2017 international conference on wireless communications. Signal processing and networking (WiSPNET). 2017. p. 117–22. [14] Settle RB, Dillon TW, Alreck PL. Acceptance of the phone-based interface for automated call direction. Behav Inf Technol 1999;18(2):97–107. [15] Charles WR. Consumer demographics as antecedents in the animosity model of foreign product purchase. Int J Bus Soc Sci 2012;3(4):13–21. [16] Digitimes. Digitimes Research: global smartphone shipments to grow 7% in 2016 and 2017. 2016. [17] K. Agrawal & Co. Smartphone industry analysis. 2017. p. 1–9. [18] Klein JG, Ettenson R, Morris MD. The animosity model of foreign product purchase: an empirical test in the People's Republic of China. J Market 1998;62(1):89–100. [19] Tan Lu, Wang Neng. Future internet: the internet of things. 2010 3rd international conference on advanced computer theory and engineering (ICACTE). 2013. p. 376–80.
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Research article
Development of user customized smart keyboard using Smart Product Design-Finite Element Analysis Process in the Internet of Things Jung Woo Kim, Sang Hun Sul, Jae Boong Choi∗ Department of Mechanical Engineering, SungKyunkwan University, Suwon-si, Gyeonggi-Do, Seobu, Ro2066, Republic of Korea
A R T I C LE I N FO
A B S T R A C T
Keywords: User customized smart keyboard Smart product design-finite element analysis process (SPD-FEAP) Smart quality function deployment (SQFD) using WebData 3D Shape analysis by finite element analysis (FEA)
In a hyper-connected society, IoT environment, markets are rapidly changing as smartphones penetrate global market. As smartphones are applied to various digital media, development of a novel smart product is required. In this paper, a Smart Product Design-Finite Element Analysis Process (SPD-FEAP) is developed to adopt fastchanging tends and user requirements that can be visually verified. The user requirements are derived and quantitatively evaluated from Smart Quality Function Deployment (SQFD) using WebData. Then the usage scenarios are created according to the priority of the functions derived from SQFD. 3D shape analysis by Finite Element Analysis (FEA) was conducted and printed out through Rapid Prototyping (RP) technology to identify any possible errors. Thus, a User Customized Smart Keyboard has been developed using SPD-FEAP.
1. Introduction Starting from 2009, smartphones have spread rapidly in the domestic market and its market share has been rising and accelerating [1]. Smartphone is experiencing a rapid growth due to its mobility, accessibility, expandability, convenience and multi-tasking. Due to the rapid expansion of Internets in 2010, high-end smartphones were developed, starting the era of Hyper-Connectivity [2]. Anabel Q. Haase and B. Wellman predicted the formation of networks in hyper-connected society would have significant impacts on the everyday lives of people [3]. New technologies were developed recently as various sensors and communication technologies are mounted on various things such as home appliances, mobile phones and wearable computers [4]. Xiaosong Hu et al. applied Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) technologies of Cyber Physical System to seek improvements in fuel efficiency by optimal control [5]. Therefore, a concrete plan and clarification of the environment on the implementation of Cyber Physical System and V2V, V2I communication must be explained in a detailed manner. It is Machine-to-Machine communication (M2M) [6–8] which controls the surrounding environment to enable each and every objects' intercommunication using sensors. M2M offers users with information that are autonomously generated from data which has been collected, shared, analyzed, and learned by internet-connected-objects [9]. Due to expeditious development in Information Technology (IT) the convenience-offering next-generation mobile communication service were highlighted. With this and the development of Internet of Things (IoT) [10,11] technology, various ∗
connection methods between people are being spread. Smartphones constructed groups that are connected via various methods such as messenger, email, and video connection [12]. As the newly connected networks [13] enabled the users with desired functions and characteristics, the purchase decision factors for smartphones have been modified [14,15]. As numerous functions were added to smartphones, recent user purchasing trends has also been shifted to shorter product life cycle and faster purchase rate. Digitime Research estimated worldwide smartphone shipments will grow 7.2% year-onyear to 1.22 billion dollars in 2016, and another 7.0% year-on-year growth to record 1.52 billion dollars in 2017 [16,17]. The keen and universal competition in smartphone industries experienced sharp increase in total sales as cutting-edge technologies such as quick charging, optical image stabilized (OIS) camera, Touch ID, etc. It is also expected that in 2019, more than 7.6 billion of the worldwide population will own smartphones due to the growth of smartphone market and production of various smartphones [18]. Users exhibited a new trend of improved utilization while connecting wireless networks regardless of time and space. The development was observed not only to smartphones where wireless networks were established all the time in IoT environment, but also to smart devices with same operating system (OS) as smartphones such as smart pads, tablet PCs, and smart TVs [19]. Smart devices [20] are now leading the global mobile market and the penetration and growth rate is on the sharp increase as they offer wide range of applications and share new information [21,22]. Recent trends show that users began to utilize converged products
Corresponding author. E-mail address: [email protected] (J.B. Choi).
https://doi.org/10.1016/j.isatra.2018.05.010 Received 12 January 2018; Received in revised form 30 April 2018; Accepted 14 May 2018 0019-0578/ © 2018 ISA. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Kim, J.W., ISA Transactions (2018), https://doi.org/10.1016/j.isatra.2018.05.010
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User requirements evaluation organizes the data quantitatively and qualitatively to be applied to the actual environment. This reduces the time taken during the designing process for smart products and analyzes any expected defects in advance using Computer Aided Design (CAD) [39–41] data for evaluation. When developing the smart product, actual usage environment of the product is taken into account to apply Finite Element Analysis (FEA) [42–46], where the morphology and boundary conditions are unlimited. During 3D shape analysis by Finite Element Analysis (FEA), additional process such as selection of appropriate thickness suitable for the designed structure, examination of formability and structural reliability to minimize problems that might occur due to external deforming factors. Simulation is done so that Users can be visually informed of the process to improve the reliability of the smart product and its developmental process. Mock-up output is printed and examined to obtain both quantitative and qualitative data for verifying accuracy and optimize morphology, and to apply Rapid Prototyping (RP) technology [47–50] for minimum modification. This process not only simplifies and complements the design by user's evaluation through RP technology, but also improves the reliability of the smart product by adopting appropriate material to ensure sufficient wear resistance. Also, by constructing a working mock-up, the internal cooling structure and the painting operation of the printing section are performed. By printing and using the smart product as a mock-up, user's evaluation is done to analyze performance error, faulty elements so that a prototype is derived similar to that of mass products at a developmental stage. Since it is possible to acquire reliability from designing to massmanufacturing, achieve shorter development period and reduce costs through these processes, it is expected that the process would gain a competitive edge within the smart product market.
adopting digital system that links smartphones to smart devices. Smart products reflect developments of hardware and software platforms based on IoT, firmware planning and various core technologies related to IoT devices [23]. Although continuous revisions of smart products [24] based on the users' requirements are vital aspect of smart product development, existing products have difficulties in their immediate revisions due to their integrated manufacturing process. As revision process for products to adopt new ideas is diversifying, high cost of mold designing and long production period became a major hindrance in product development [25,26]. In mold design process in the fields, this manufacturing method relies mostly on experienced developers rather than reflecting the users' requirement in the mold design stage in the field. Thus, this causes dimensional errors, complicated design processes, and time-consuming operations for mass production. Thus, the manufacturing processes are experiencing a transition to modular manufacturing process in order to instantly reflect users' requirements. Subjects related to smart products, which are suitable for modular manufacturing, are being studied to systemize and modify 3D image output from 2D image, minimize residual stress, and optimize molding condition for maintain precision for performance. To develop a smart product that is suitable for modular manufacturing, intensive research efforts are underway, like systematizing the output, modification, and supplementation of 2D images into 3D shape, minimizing the residual stress formed in the product during design verification, and optimizing the molding condition [27,28]. Emerging trends show that the products' life cycle [29–32] is shortening. However, products' quality evaluation and verification for smart products are yet to be researched. Thus, a novel method of development for smart products is required so that User Experience Design (UX) [33–35] is taken into consideration. Goedkoop et al. introduced Product Service System (PSS) as a user-centric design process [36]. Although PSS is used to satisfy the users' requirements, there are limitations to develop appropriate products for ongoing trends. Joseph T. Emanuel and Dennis E. Kroll [37] proposed a systematic approach to product designing and processing that can be drawn simultaneously. In order to produce smart products that users want, emphasis must be put on the importance in design, reliability of performance and practicality during the manufacturing process [38]. Therefore, a simple, convenient, mass customized Smart Product Design-Finite Element Analysis Process (SPD-FEA) is developed. In this paper, a User Customized Smart Keyboard that meets the underlying trend in hyper-connected society has been developed using SPD-FEAP. This process quantitatively analyzes users' requirements from Smart Quality Function Deployment (SQFD) using WebData. Information such as preferences to products, usage patterns, and lifestyles are comprehensively considered to determine the concept. As a quantitative analysis method, Usage scenario with storytelling are adopted in order to enhance the degree of comprehensibility so that functions, figure, sizes would reflect the actual product usage environment to formulate product's specification.
2. Development of Smart Product Design-Finite Element Analysis Process (SPD-FEAP) In a hyper-connected society, IoT-based environment, the usage of smart products is changing rapidly due to varying lifestyles of the users and their activeness in sharing and competing online. Although the demand for smart products is experiencing a sharp increase according to current, fast-changing trend, there exist difficulties in developing a smart product with user requirements reflected. The trend for manufacturing products has also influenced method of manufacturing, thus experiencing a shift from mass production to mass customization. As converged technologies are applied to the products, the developmental period is shortening from simply developing hardware and software to developing high quality products for enhanced precision for performance. A novel design process that can continuously acquire users' requirements and analyze requisite of products and thus adopt to current fast-changing trends in hyper-connected society. To adopt a different view from technology-intensive manufacturing,
Fig. 1. Smart product design-finite element analysis process (SPD-FEAP). 2
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3. Verification of Smart Product Design-Finite Element Analysis Process (SPD-FEAP)
a User Customized Smart Keyboard has been developed with SPD-FEAP as shown in Fig. 1. In order to derive a desired quantitative analysis from big data, wide range of consumers' comments are collected to analyze their interests and trends per period. Keywords are derived from latest market trends and studied using Google Trend offered by Google and Amazon websites for international trends, Naver Trend and their blogs offered by Naver for domestic market. These users' requirements are extracted from non-structured data, which are rapidly increasing online in hyper-connected society, and applied SQFD to structuralize the data. In developing a smart product, SQFD using WebData is conducted on users' requirements that were extracted for quantitative evaluation. During this analysis, the information is classified into various categories such as products' preferences, usage patterns and lifestyles. In manufacturing a smart product, critical parts and components are identified and arranged as scoring system so that each parts can be analyzed in terms of importance and user satisfaction. Also, keywords that offers users with optimal UX have been extracted and analyzed their data patterns through quantitative evaluation so that the smart products can be actualized. When establishing basic concepts and design phases in developing smart products, all steps can be systematically connected to identify feasible problems, design considerations, thus reducing the change of design. Taking the users' purchasing patterns and lifestyles including information such as sex, age and occupation into account, smart products reflect users' emotional elements in usage scenario with storytelling for qualitative evaluation. Also the material property and their texture difference due to the existence of glossiness verified in terms of emotional aspects. As a result, reflecting fun elements, users' understanding of the product was improved while the core elements for the development that suits the trend were derived and applied to actual functions. 3D shape analysis by FEA was conducted in virtual space to analyze elements that cannot be done in real-life tests to visualize the user's evaluation results. Thus anticipating errors regarding precision of performance during the design process. Product's strength, stress analysis and material property has been chosen to meet the users' requirements. 3D shape analysis by FEA was conducted according to the users' requirements to visually confirm and discover any problems of the smart product at an early stage. Also the reliability of the prototype was improved by anticipating their performance and verifying safety and presence of defects. Adopting fast-changing and trend-sensitive users' requirements to smart products requires RP so that important elements such as accuracy of data, swift development and reliability are satisfied. By minimizing the required process in complicated product designing, RP enables the smart product to be verified not only in developmental stage but also in mass production. A life-size prototype has been made according to the design blueprint that has been modified with colors, shapes, impressions, etc. Also, a working mock-up where internal parts can be linked each other was printed out to examine any drawbacks to performance. From this, the unnecessary costs of time and resource for mold designing and mass production are reduced to minimum during the user's evaluation. Moreover, the users' requirements can be reflected instantly and conveniently in the evaluation, not only it can reduce the costs for mass production. A life-size prototype has been made according to the design blueprint that has been modified with colors, shapes, impressions, etc. Also, a working mock-up where internal parts can be linked each other was printed out to examine any drawbacks to performance. From this, the unnecessary costs of time and resource for mold designing and mass production are reduced to minimum during the user's evaluation. Moreover, the users' requirements can be reflected instantly and conveniently in the evaluation, not only it can reduce the costs for mass production.
User requirements are critical aspect in analyzing the current trends of newly developed products and they are applied to SQFD with measured weights in the order of priority. The process thereby results in the improvements of the product. Data related with user requirements are used to derive necessary aspects of the products in a quantitative methodology. Also, usage scenario with storytelling for qualitative evaluation are made so that users can easily apply them during the actual usage. A user evaluation has been conducted to understand the critical functions and problems of the product. Based on this evaluation, an idea sketch, 2D sketch and 3D modeling were done. Through this series of evaluations, the convenience, usability and feasibility of the detachable design are verified. Lastly, a Finite Element Analysis (FEA) is applied to 3D modelled object to examine the mechanical reliability and safety of the product. 3.1. Quantitative evaluation method for smart product development Unstructured data is increasing with the spread in the use of Internet-based Social Network Service (SNS) that can confirm recent trends. In order to grasp the user requirements, passive data were extracted at the stage of WebData. We watched over the representative online sites, Google (www.google.com) and Naver (www.naver.com). Then the SQFD was applied which works as storage, management, and analysis of the user requirements through trend analysis and user comments, and reviews of products. The correlation between extracted WebData and functions that were prioritized were derived. These improvement points serves as methods for implementing new functions, and confirmed the problem. Fig. 2 shows that the user requirements extracted from online WebData of Google and Naver were derived through quantitative analysis by measuring their weights in the order of priority. The higher the word frequency, the more important the keywords that were extracted according to the frequency of similar words, and summarized. Frequency grasped specific words of user requirements were used to determine their importance. Weight is given to keywords according to the extent of analysis and the evaluation shown in sentences. As a result, SQFD organizes the horizontal axis as user requirements, and the vertical axis denotes desired functions according to user requirements. Fig. 3 shows that important elements of the product are derived according to the user requirements through SQFD, and the communication method, product shape, and product material are organized. The Bluetooth technology, which is a current dominating wireless communication technology, is on the steady rise. However, the reaction time increases as the communication range increases, and the fact that it consumes additional smartphone power source without batteries inside the smart product, a separate measure was to be applied. In order to solve this, USB standard functions USB On-The-Go (OTG) is adopted to be used as a communication method. With the increased development of various interface devices, it is effective to reduce weight and capacity by installing USB OTG into a very thin outer shape design. In addition, charging terminals of smartphones can be wired to be compatible with external I/O devices, and the inconveniences of battery replacement can be minimized. As a product form, we considered a method of simply placing a smartphone using a straight line-centered design. Considering the mobility to be used, we pursued a stable coupling system by designing a jaw that prevents the smartphone from detaching. Also, we used USB OTG to minimize the smart product weight burden, and to use the smartphone battery power. The pattern touch interface in which the user operates the smart product was considered, to enhance usability. The material of the product can express various colors, and liked the apparent material with plastic excellent in mold ability. On the top of the product, based on user requirements, we chose a removable 3
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Fig. 2. Quantitative analysis of Smart Quality Function Deployment (SQFD).
smartphone and floor to prevent shaking. Applying a rubber that can grip onto the top end of the smartphone prevented it from slipping. Considering the usage environment, we improved the reliability of the product by considering its durability, wear resistance design, and life waterproof design. We applied sensitive parts, such as communication method, product form, and product material, as necessary elements for developing smart products. Table 1 shows the result of deriving user requirements based
on the priority in correlation with smart quality function development applying big data, systematized for qualitative evaluation. 3.2. Qualitative evaluation method for the analysis of the actual functions We conducted qualitative evaluation to naturally induce the participation of users who are influenced by the trend of the hyper connected society. Using the data of user requirements derived with
Fig. 3. SQFD as essential function of User Customized Smart Keyboard. 4
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3.3. 3D modeling design visualization for user evaluation
Table 1 User requirement analysis to developing User Customized Smart Keyboard. User requirement
Result
1 2
If you can easily separate the smartphone and the keyboard If you have a sense of grip that makes it easy to pick up the keyboard design If the portability is good with a structure easy to use anytime and anywhere If the font of the keypad is printed cleanly and there is no difficulty finding characters If there is less input error than the touch keyboard and you increase the accuracy When the use time increases compared to the charging time
3 4 5 6
Three user requirements that summarize usage scenarios are proceeded at the design stage. We evaluated the user using idea sketch, 2D sketch, and 3D modeling, so that we could actually visualize the product. Design verification that emphasizes ease of use and convenience is necessary, so that smartphones can be attached and detached. Smart product design analyzes the problem expected when using it in an actual environment by FEA, and confirms its validity. RP was applied at the mock-up stage of the product and the working mock-up designed, after the user's evaluation of the final 3D design. We can visually express the problems that can exist, rather than simply describing the product as it is at the stage of idea design sketch. In order to develop the form of a new design, we emphasize the shape of the stereoscopic design according to the perspective technique, the pen sketch technique that exploits the relationship between shades and the line expressed by different thicknesses. In order to visualize the user requirements implemented in the usage scenario, we developed the design by adding colors to reflect smart product sketches. Application of the usage scenario to the UX and the environment expresses various post processing and text on materials for the required design. As a result, the user requirements was reflected, and idea sketches A, B, and C made it easy to understand not only for the unique design, but also to derive suitability for use. Fig. 5 shows an idea sketch of a type based on ergonomics that a user can adapt easily in everyday life. It is a concept design that can attach and detach various types of smartphones with adhesive pads, with a built-in silicone type keypad. The human-centered idea sketch B type provides users with a new experience. A single PCB and a keypad are built into a thin plate material, and the design under which the protruding face under the second half of the keyboard is connected with the smartphone to emphasize the grip feeling. The idea sketch C type can be customized according to the personality of the user. It is a concept design composed of a connection terminal and a cover that supports the back of the smartphone with a folding structure, considering the portability. The idea design sketch designs CAD data using 2D CAD, such as points, lines, planes and graphic symbols for the visual user requirements organized at the stage. It is possible to easily reflect the drawing by changing the precise dimensions. Design 3D modeling allows the interference of parts to be checked at the stage of modeling, problems with the assembly, and design elements with the silicon type keypad built using Inventor v.15.0, which is a 3D design program.
applying the storytelling use scenario, it was complemented to develop smart products. Based on the UX, we can interact with each other at all development stages by user participation, use, and observation. We arrange in order of high evaluation among user requirements derived by correlation and extract contents of rank 1 to 3. In the early stages of development, we consider user profiles, preferred functions, and applicable product functions. From the user point-of-view, we set the purpose of use and duration of use of the product virtually, and describe it based on six principles to facilitate fundamental understanding of the product. Derivation of new functions for product design and product concept can be organized based on user requirements, and errors can be minimized. Fig. 4 shows that we derive qualitatively for User Customized Smart Keyboard development based on the creation of a usage scenarios. We determined priorities by considering the functions and problems actually required by the based on user requirements derived from important keywords through SQFD, we created a usage scenario to create empathy associated with lifestyle. By presenting the usage scenario in the form of a story in a qualitative way to easily convey the contents to the user with important keywords, it is possible to enhance the degree of understanding of the product. We applied the user requirements to the actual lifestyle to derive a simple attachment and detachment method, a design with excellent grip feeling, and portability and simple structure. By defining functions and specifications suitable for improving the ease of use necessary for the development of smart products in the use scenario based on the storytelling executed at the planning stage, we were able to design an ergonomic smart product.
Fig. 4. Test usage scenario applying storytelling for qualitative evaluation. 5
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Fig. 5. Idea sketches applying three functions of User Customized Smart Keyboard.
Fig. 6. User Customized Smart Keyboard of 3D modeling shape reflecting user requirement.
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Fig. 7. Design condition and boundary condition for the analysis of User Customized Smart Keyboard. Table 2 Design condition of User Customized Smart Keyboard for FEA. No
Case name
L (mm)
Lpad (mm)
Lkey (mm)
W (g)
Tpad (mm)
1 2 3 4 5 6
A-1 A-2 B-1 B-2 C-1 C-2
135 135 81 81 109.7 99.56
75 75 75 75 50.14 40
60 60 60 60 59.56 59.56
65 65 67 67 65.2 65.2
3.5 1.6 3.1 3.1 1.6 1.6
By evaluating the user requirements so that the PCB and the keypad are built in a thin plate material, the projected design below and the design of the folding structure considering portability can be visually confirmed. Fig. 6 shows the 3D modeling shape based on CAD data. This enables the appearance of the design to be examined and the function of the product to be considered. The synthesis of the type of design to be studied, the hardware design to be checked along with water mount ability considerations, etc. Also, design errors can be prevented, and correction work can be done in advance. This reflects the user
Fig. 9. Von mises visual results of finite element analysis for user's evaluation.
requirements at the User Customized Smart Keyboard 3D modeling design stage. In advance, we analyzed all problems expected in the mock-up, working mock-up, and final model production process and
Fig. 8. User customized Smart Keyboard models as Finite element analysis users Evaluation. 7
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Fig. 10. User Customized Smart Keyboard reflecting user requirements A, B, and C models.
suitable for the structure, consider the formability and influence factors of appearance deformation. We could evaluate users by using 3D shape analysis by FEA of the design and development of smart products. By reducing the process of repetition and correction of preview, it is possible to shorten the development period, improve quality and reduce costs. Fig. 7 shows that the loading conditions are shown in red for the conditions used for FEA, and certain conditions were displayed in black, so that the user could easily understand the design visually. The weight of the smartphone is 158 g on average, designating it as a boundary condition, handling of the back of the keyboard of the smartphone, and considering certain conditions. In order to check the overall stress of the product, the detailed mesh setting was set to Hex Dominant using automesh. As loading conditions, mechanical loading was considered. Generally, when the user uses a keyboard, the pressure required is about 50 g. Thus it is expected about 60 g force in touching each keypads and assumed so. With the same material as the 3D printed material in the actual usage environment, the User Customized Smartphone Keyboard material advanced analysis used polycarbonate EH-1050. Selected for analysis conditions, EH-1050 polycarbonate is a resin product with one kind of thermoplastic resin, resin layer in glass fiber layer. As a result, characteristics such as impact resistance, durability, heat resistance, weather resistance, self-miniaturization and transparency were taken into consideration. As a result, detailed design condition of the model made into the 3D shape of the six models of the User Customized Smart Keyboard, so that it can be combined with the smartphone presented as shown in Table 2. Where, L is the User Customized Smart Keyboard length and pad length, Lpad the User Customized Smart Keyboard pad length, Lkey the
Table 3 Improved design condition of User Customized Smart Keyboard for FEA. No
Case name
L (mm)
Lpad (mm)
Lkey (mm)
W (g)
Tpad (mm)
1 2 3
A B C
135 135 125.77
75.5 75 72.41
59.5 60 53.36
65 67 65
3.0 3.1 2
proceeded with user's evaluation to obtain the optimum design data. In accordance with the user requirements, we derived six models based on designs that marked the highest user ratings. Each models have different designs by built-in silicon type keypad, PCB on thin board material, extruded design under, and folding structure considering portability. By applying it to a series of several composite materials, we could apply FEA that can be utilized in all fields. The design was confirmed without restrictions, such as geometrical shape, load, and boundary conditions using 3D shape analysis by FEA. 3.4. 3D shape analysis of user customized smart keyboard by finite element analysis (FEA) 3D shape analysis by FEA the smart product design could be improved and modified according to user requirements for shape analysis. The accuracy could be increased by enlarging the mesh size of the smart product and the number of elements, and grasping the possibilities of actual products. In order to evaluate the strength, we could check the maximum stress and deformation amount, while applying the results to the user's evaluation of the smart product in a similar manner. Also, we could check the mechanical reliability through FEA and confirm it to improve product safety. We could determine the selection of thickness 8
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Fig. 11. Results of User Customized Smart Keyboard A, B, and C models via FEA.
models. Using the model of the User Customized Smart Keyboard, we analyzed any possible errors that can occur in the actual environment. Fig. 8 shows that the FEA was confirmed by six models according to user requirements. In the Lpad part of the A-1 model, a horizontal stress distribution occurred. The model of A-2 confirmed that the stress was intensively distributed on both sides of Lpad, with the curved surface Lpad shape supporting the smartphone. The types of stress concentration phenomena occurring of B-1 are almost the same and the stress concentration phenomenon displayed by the B-1 model appears more widely distributed than that of the B-2 model. In C type with Lpad length shorter than for A and B, model, we confirmed the overall stress distribution phenomenon in the Lpad part. In the C-1 model, the Lpad method was designed as a slide type, and a high stress concentration phenomenon occurred at the connection part. In the C-2 model, high stress concentration phenomenon was confirmed in the Lpad and Lkey parts. The FEA was used to develop smart products that reflect the user requirements for A, B and C models. For A, B, and C models, the Lpad part where smartphones and keyboards adjoin showed greatest stress concentration. Fig. 9 shows the visual results obtained by performing FEA on six models of the User Customized Smart Keyboard reflecting the user requirements, which are summarized in a graph for user's evaluation. For the A-2, C-1, and C-2 models located above the von mises stress of 2.5 × 106 pa, the structural features by user requirements were taken into consideration. In the case of the B-2 model, the positions A-1 and B1, which are below the average, have a low probability of failure and a stable structure. In the primary evaluation, the user has confirmed the necessary models. Fig. 10 shows the comparisons between A-1 and A-2 models, which are the designs that reflect user requirements, where small stress
Fig. 12. Visual result of improved von mises for finite element analysis for user evaluation.
User Customized Smart Keyboard length, W is the User Customized Smart Keyboard weight and Tpad is the thickness of the keyboard of the smartphone. We derive the visual results of the FEA from the user's evaluation and consider the User Customized Smart Keyboard. We investigate failure cause beforehand, to confirm mechanical problems in the design. As a result, by searching for a solution, errors in precision of performance are minimized in the course of additional improvement work. FEA confirmed the stress distribution and stress concentration of smart products using Ansys ver.18 workbench, a commercially available structural analysis program. We confirmed with 6 full models as 3D FEA 9
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Fig. 13. User customized smart keyboard mock-up extracted by Rapid Prototyping.
Fig. 14. Derived user customized smart keyboard A model.
4. Application of Smart Product Design-Finite Element Analysis Process (SPD-FEAP)
concentration was identified. In the case of the C-1 and C-2 models, the high stress concentration phenomenon was grasped in the Lpad and Lkey parts in the C model with improved cover type with slide shape. The results of the FEA of six models of the User Customized Smart Keyboard showed that considerable stress concentration phenomenon occurred between the keypad and keyboard. In order to improve this, FEA of the advanced design condition of the model was conducted for three design supplemented models. These improved models are shown in Table 3. We proposed three FEA s by deriving three 3D modeling reflecting the user requirements in the User Customized Smart Keyboard, which was complemented through user's evaluation. Fig. 11 shows the User Customized Smart Keyboard that joins the smartphones predicted the possibility of the thickness of the Lpad surface being damaged, depending on the amount of deformation of the product. We also confirmed that the back side of the User Customized Smart Keyboard has an influence on the deformation volume. During the user's evaluation, the User Customized Smart Keyboard A was chosen since it emphasized portability and convenience showed that horizontal stress distribution occurred, compared with the two models of the Lpad part. Through the secondary evaluation, we proceeded to FEA of three models of the User Customized Smart Keyboard reflecting user requirements, as shown in Fig. 12. Based on the von Mises stress of 2.5 × 106 pa, we confirmed that all models A, B and C have high stability as the von Mises stresses of each models were located far below the average that was assumed for the FEA.
Rapid Prototyping technology is applied to create a prototype of the smart product in order to revise and complement the design blueprint. Finite element analysis of the 3D modelled object enables to check any possible errors of the design in advance. 3 different mock-ups according to the users' requirements are created using RP. Taking UX into consideration, the internal mechanical structure of the product is reviewed and evaluated for possible improvements. As a result, a working mockup of User Customized Smart Keyboard reflecting user requirements and current trends are made in considering the products' reliability and convenience. 4.1. User customized smart keyboard verification for Rapid Prototyping (RP) Continuously reflecting the user requirements in a hyper-connected society, we develop prototypes that can modify and supplement design drawings by applying RP in the development smart products. By developing smart products of various types in small quantity production, they can be produced inexpensively and efficiently, while production efficiency can be secured by shortening the design time. Fig. 13 shows smart products A, B, and C types via RP, with a modified FEA reflecting the user requirements. Visualization and 3D modeling of the keyboard reflecting the users' requirements were determined from the shape analysis. Then, RP was 10
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Fig. 15. User customized smart keyboard rendering image.
Fig. 16. User customized smart keyboard Working Mock-up.
design, before making them into the actual product. In addition, we determined mass productivity, assembly, type synthesis, etc. through mock-up and working mock-up production of smart products that can reflect user requirements repeatedly in the design process to match
conducted to confirm the size, shape and grip feeling of the actual size. One major advantage of adopting RP technology is that it is possible to quickly reflect complementation in the correcting process, by checking the prototypes. This would minimize errors that can occur during 11
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Fig. 17. Operation test of user customized smart keyboard.
writing ‘Hunminjeongeum’. The keyboard was made in two models, which have red and blue color. According to the user requirements, the red model adds glossy color which emphasizes luxury, while the blue model considers refinement.
current trends. While still considering the UX, we designed an optimized design to ensure the wear resistance of the painted and printed parts. By checking and evaluating the internal mechanism, improvements were further made by increasing the performance by confirming the creation, interference, etc. by the combination of each part. Fig. 14 shows an ergonomic design of the User Customized Smart Keyboard based on FEA that was considered. Small type, slim type, folder type and flexible type were devised and designed with an emphasis on portability and detachability. Based on the user's evaluation, we designed the User Customized Smart Keyboard so that when the user grabs the keyboard with both hands, it provides comfort to the wrist. Moreover, convenience of the product was also taken into consideration by minimizing the difficulty of its operation, as it is immature and difficult to operate. We implemented a User Customized Smart Keyboard that minimizes the constraints of activities, without feeling discomfort at the time while using. The UX was applied to ergonomic design to protect the wrist with the same size as the actual product. Fig. 15 shows the consideration of the sensational aspects of the user in the rendered image of the finishing parts that have been confirmed with scale, volume and color of User Customized Smart Keyboard. Then the user's evaluation was conducted on user's perspective to the surface property, volume and texture in User Customized Smart Keyboard.
5. Conclusions In hyper-connected society, as lifestyle patterns based on smartphones have been spread globally, small input screens of smartphones became a hindrance for interaction. In order to tackle this problem, users are increasingly using smart products as converged products as a communication method. Smart products are converged products sensitive to current trends which makes reflecting of user requirements a vital element in development. In this paper, a User Customized Smart Keyboard that meets the underlying trend in hyper-connected society has been developed using SPD-FEAP. Functions that user requirements indicated were derived from SQFD using WebData. The prioritized user requirements that were then put down into various usage scenarios for qualitative analysis. Through this process, a User Customized Smart Keyboard was developed having functions that users actually require the most while associated problems were identified in advance. In order to pre-identify the feasible problems in advance after the user requirements were adopted, user's evaluation was made with 3D shape analysis by FEA. Strength, noise and vibration was taken into consideration during tests for actual usage environment with FEA. As a result, the joint between the smartphones and the User Customized Smart Keyboard showed greatest stress concentration. Strength evaluation was conducted to verify maximum stress, deformation, stress distribution, loading conditions and selection of material to figure out any structural problems from identified fault-causing factors. Three models of User Customized Smart Keyboard that adopted user requirements were conducted with FEA. As a result, it has been confirmed that all models A, B and C showed high stability with 2.5 × 106 pa of von mises stress, located below the average value. In order to visually confirm the FEA results, user's evaluation was conducted with smart products A, B and C by printing out in 3D shape according to the design blueprints. Also, by creating a mock-up, each parts' interference with the assembled shape and assembly tolerance was confirmed. Considering the actual working environment, a working mock-up is then created to verify the smart product's life size, quality and grip feelings. As a result of reflecting user requirements for portability and convenience, the User Customized Smart Keyboard model A
4.2. User customized smart keyboard working mock-up Using the results of the rendered image, we chose the appropriate material for the User Customized Smart Keyboard to ensure abrasion resistance. Fig. 16 shows that modeling for enhancing product reliability was selected. We developed the User Customized Smart Keyboard PCB through execution and development of coding of firmware for USB OTG operation. In terms of functionality, the model was designed to minimize the volume using smartphone batteries, as well as being removable from smartphones in combination with a USB type of User Customized Smart Keyboard. In addition, the optimum design keypad of a circuit that can be driven for a long time constitutes a 20 EA button. In place of the basic 12EA button, we placed an input assistance function key 8EA button that emphasized ease of use for languages, basic 12EA button. The button operation part was designed so that users can feel analog esthetic from digital equipment by implementing a vibration touch interface. We applied a design that can provide detailed operation and input feedback that had been impossible with touch. Fig. 17 shows the operation test of User Customized Smart Keyboard 12
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has been chosen. The user requirements were then visually presented to improve precision to user's evaluation result. User Customized Smart Keyboard was designed as ‘Cheonjiin’ styled 20EA keypad buttons. 12EA buttoned keypad was added for input languages without word spacing and 8EA function buttons for auxiliary inputs emphasizing convenience. At the operating button, vibrational tactile impression interface has been designed to enable users with analog esthetic from digital devices, detailed manipulation, feedbacks from inputs. Utilizing SPD-FEAP as a developing process, it is expected that the quality of the smart products, which are trend-sensitive, will be improved and will minimize the time and cost during the development. Also, the research not only alleviates difficulties in smartphone based communications in an IoT environment, but also to form a whole new market in the Age of Digital Civilization. The current study on SPDFEAP continuously applies converging technologies to react to fastchanging trends. Hereafter researches on the development of IoT-based smart products that can provide customized services are expected to be made.
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