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Performance evaluation with DEVS formalism and implementation of active emergency call system for realtime location and monitoring
Simulation Modelling Practice and Theory 18 (2010) 416–430
Contents lists available at ScienceDirect
Simulation Modelling Practice and Theory journal homepage: www.elsevier.com/locate/simpat
Performance evaluation with DEVS formalism and implementation of active emergency call system for realtime location and monitoring Young-Sik Jeong a,*, Won-Hee Han a, Eun-Ha Song a, Sang-Soo Yeo b a b
Department of Computer Engineering, Wonkwang University, Republic of Korea Division of Computer Engineering, Mokwon University, Republic of Korea
a r t i c l e
i n f o
Article history: Available online 17 September 2009 Keywords: LBS (Location Based Services) GPS (Global Positioning System) Realtime monitoring DEVS (Discrete Event System Specification) Object location tracing
a b s t r a c t In this paper, we designed and implemented the active emergency call system for emergency call service actively. Active emergency call system has two physical components; E-Device (Emergency Mobile Device) and E-Server (Emergency Server). The role of EDevice is the mobile device in order to call emergency by using mild handicapped, the elderly and children who are able to communicate their intention to another. E-Server is the server for management E-Devices with realtime monitoring. E-Device will be developed to the portable size for easily mild handicapped, the elderly and children. When they need the service of emergency call, the button of E-Device can be used and the call signal is transmitted to the emergency office and the guardian through Internet and CDMA. E-Server should be developed the integrated control system for management of E-Devices basically. And it also supported to realtime monitoring of E-Devices with respect to high quality of emergency call service for rise the efficiency. And finally we describe the results of performance evaluation about the location error of E-Device between coordinate of GPS received signal and actual E-Device coordinate, when it has been called emergency, by using DEVS (Discrete Event System Specification) formalism. Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction Due to recent development in ubiquitous technology, location information technology service is being used in various fields in real life. u-Lifecare system, utilizes location information service technology to locate the handicapped, the elders, or missing children. Nevertheless, most of recent u-Healthcare location information services are established overly dependent on certain type of communication network environment; moreover, there are many services with similar characteristics that are not compatible with each other thus creating overlapping services. In establishing alarming system, existing uHealthcare system can only provide emergency call and the simplest information on the patient’s location, and cannot provide adequate treatment. In other words, current u-Healthcare location tracing system and emergency service system lack active service call mechanism that is proper for different patients. This paper develops active emergency call system, an emergency call service system for the minorities including the handicapped, elders, and children. Active emergency call system is composed of two components: E-Device and E-Server. E-Device, in emergency situations, actively sends signal to emergency institutions and guardians, and requests help through wire and/or wireless network. E-Device is designed in such way that it is portable and easy to use due to special characteristics of its primary consumers. And to conclude for efficient service, it should provide cheap and low-cost service for the handicapped and the elders. We manufacture low-priced E-Device and support eliminating unnecessary service fees so that * Corresponding author. Tel.: +82 63 850 6746; fax: +82 63 856 8009. E-mail addresses: [email protected] (Y.-S. Jeong), [email protected] (W.-H. Han), [email protected] (E.-H. Song), [email protected] (S.-S. Yeo). 1569-190X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.simpat.2009.09.006
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the primary consumers (the handicapped, the elders, and children) can easily access to emergency service and receive proper treatment through institutions and their guardians. It also supported realtime monitoring function by using GML standard map visualization and location tracing mechanism in order to manage E-Devices. And finally we show the results of performance evaluation for the location error of E-Device between coordinate of GPS received signal and actual E-Device coordinate, when it has been called emergency, by using DEVS (Discrete Event System Specification) formalism. E-Server is designed for comprehensive management of all the E-Devices and related emergency calls. E-Server locates and visualizes situated E-Device in realtime, and actively forwards emergency information to emergency institutions and patient’s guardian. When the emergency call button on the E-Device is pressed, location information of E-Device is collected by active emergency call system through GPS satellite, emergency calls are forwarded to E-Server through CDMA, and the specific information is sent to emergency institutions and guardians through SMS by E-Server. When active emergency call system receives emergency call signal, it traces location of the patient in realtime through realtime emergency situation monitoring. It also sends the realtime information to institutions and guardians through SMS.
2. Related works There are several existing location information services: myPol by KLIC Ltd., Emergency Help Service by icarefree Co., SOS Service by SK Telecom, E-Call Service by Europe and ACMA by Australia. It uses TDOA technique to locate mobile station by calculating the time difference between local trans-receiver and the mobile station [1,2]. In order to locate local trans-receiver in exact, one or more TDOA values are needed; therefore, in order to utilize myPol service, great number of trans-receiver must be installed in wide range of areas, thus resulting in expensive budget [3–5]. icarefree’s Emergency Help Service and SOS Service by SK Telecom both utilize GPS for location tracing. GPS operates on 24 NAVSTAR (Navigation System with Time and Ranging) satellites; each four satellites are allocated into six different circular orbital surfaces on 20,183 km altitude, acquiring information on latitude, longitude, altitude, even velocity and time information [6]. GPS uses trigonometry to calculate location [7]; therefore, it leaves wide error range when calculating location in urban areas. E-Call by Europe, which has GPS and mobile communication technology functions, is transferring circumstance of Car’s accident as message to each station. ACMA Service by Australia is providing local information and emergency situation by local telephone and mobile phone. Those systems use existing CDMA network, so it requires relatively small initial capital. There are various location information services other than suggested existing services; however, most of them require expensive equipments, and additional service fees are required as well. Active emergency call system provides cheap service using low-priced device and eliminating unnecessary service fees so that the primary consumers (the handicapped, the elders, and children) can easily access to emergency service and receive proper treatment through institutions and their guardians. Active emergency call system uses realtime monitoring technique using GML standard map visualization and location tracing mechanism in order to manage E-Devices.
3. Active emergency call system The Active emergency call system is composed of E-Device, E-Server, and software for emergency institutions. E-Device collects location information from GPS satellite, and sends the location information with its own data to E-Server through CDMA network when emergency call button is pressed. E-Server collects personal information, the user’s location information, and the user’s guardian information, and sends the information to emergency institutions and guardians while running realtime location trace monitoring on the device. The software displays received location information and medical history of the patient. Fig. 1 shows overall operation environment of active emergency call system [8]. 3.1. E-Device E-Device is active emergency call system’s portable device sending emergency signals. As shown in Fig. 2, E-Device is composed of three parts: CDMA Module for communicating with active emergency call system’s server, GPS Module for locating the device’s location, and Process Module which executes emergency call routine. Qualcomm’s MSM6025 is used for CDMA Module. It is a wireless CDMA200 1X internal modem in 800 MHz range that has voice/data transmitting feature connecting to CMDA wireless network. It receives transmitted data from Process Module through UART 1 running Atmega 128 HOST and RS-232 Serial Communication, and transmits the data to E-Server. GPS Module amplifies transmitted signal from GPS satellite through two steps and eliminates noises using SAW Filter and Line Filter. Amplified and processed signal is then transmitted from GPS RF Front END (GRF3i/LP) to GPS Engine Processor (GSP2e/LP). GPS Engine Processor then transmits the signal to Process Module through RS-232 Serial Communication in string form. Process Module is a MicroProcessor, responsible for actual calculations. It uses two UARTs and communicates between CDMA Module and GPS Module. UART 0 has 115,200 bps transmitting speed and operates CDMA Module and its communication; UART 1 receives RS-232 string data from GPS Module. Process Module’s External Interrupt is connected to emergency call button, so when the button is pressed External Interrupt runs emergency call routine. When emergency call routine is
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Fig. 1. Operation environment of active emergency call system.
Fig. 2. E-Device structure and components.
called upon, it is connected to designated gateway through CDMA, and transmitted coordinates from GPS Module and the device’s unique ID are transmitted in string form. 3.2. E-Server E-Server is active emergency call system’s main server for comprehensive management of E-Devices and adequate response for emergency situations. E-Server is composed of various components: CM (Communication Module) which enables two-way communication with E-Server, SP (Signal Processor) which extracts data from E-Device by analyzing signals transmitted through CDMA network, NM (Network Module) which manages devices’ location by analyzing extracted data from SP, MM (Monitoring Module) which is responsible for realtime location tracing and monitoring visualization, EM (Emergency Module) which notifies the emergency situation to emergency institutions and guardians, and Database that stores patient’s personal information and medical information. Fig. 3 shows detailed structure of E-Server.
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3.3. Emergency Call Scenario and Emergency Call Protocol When emergency situation occurs, E-Device sends emergency call to E-Server, and when ACK Message is received from the server, E-Device sends its location information periodically to the server in order to reduce communication cost. When Emergency call is sent from the E-Device, E-Server then analyzes the device’s location information and its ID through Signal Processor. Emergency Module meanwhile connects to DB, downloads user’s personal information and medical history, and makes emergency call to Emergency Center. Monitoring Module monitors device’s location status and emergency response process from the beginning to end of the situation. Fig. 4 shows active emergency call system’s service scenario and communication protocol. 4. Realtime location and monitoring 4.1. Location management Network Module (NM) constantly manages E-Device’s location and sends emergency signals. It also manages E-Devices’ network. Fig. 5 shows detailed component structure of NM. NM is composed of three components: Data Management, VO (Virtual Organization) Information, and Location Contact. Data Management component analyzes, processes, and stores the data from SP. Event Dispatcher sends the data to related components, and Event Extraction extracts the data from Event Dispatcher and divides them into two categories: data to be stored in the DB, and events to be processed. Extracted data are stored in Data Repository/Query Repository through Query Processing. VO Information component analyzes network information to which E-Device is connected. When a network event is created by Event Extraction, Processing Filtering extracts network information from the storage. Extracted network data is then sent to VO Information component through Event Dispatcher, and VO Information visualizes the data onto the administrator system. Location Contact component receives extracted E-Device’s location information by Data Management from Event Dispatcher and stores them at Location DB. 4.1.1. Meta Information Component Meta Information Component requests hardware information on E-Device from administrator, and saves the creation information in meta information management DB. Fig. 6 shows the specific structure of Meta Information Component. Meta Information Component is consisted of several components: DCI (Data Communication Interface), CA (Command Analyzer), SE (Search Engine), MM (MetaInfo Maker), XG (XML Generator), XT (XML Transmitter), and MetaInfo DB. When client implements Meta info-related event, the event itself transmits a command event from Meta info scheme through DCI. The command event received by DCI analyzes the event, of which the administrator is to implement, through CA. Using the analysis result, the command event then searches meta info related data, and calls corresponding command by determining whether the search data is a new meta information input or not. When a command for new information input on meta information is requested, a administrator calls MM. MM analyzes meta information-related XML data transmitted from a administrator, and inputs the result in E-Device DB. When a client request meta information data, MM creates E-Device DB search query through SE, and searches E-Device DB based on the created query. XG creates XML document containing data search result through SE. XT then forwards created XML documents to the administrator that initially requested command implementation through DCI.
Fig. 3. E-Server structure.
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Fig. 4. Service scenario and communication protocol of active emergency call system.
Fig. 5. Network Module for location management of E-Device.
Fig. 6. Meta Information Component.
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4.1.2. Control-Query Component Control-Query Component controls E-Device and it request Database information such as E-Device control command, user information, E-Device installation information, and so on. Fig. 7 shows Control-Query Component’s specific architecture. Control-Query Component is composed of several components: DCI (Data Communication Interface), CQA (Control and Query Analyzer), DQG (Database Query Generator), DP (Databases Processor), XT (XML Transmitter), CP (Context Provider), RD (Rule Discriminator), RE (Reasoning Engine), QO (Query Operator), and Database. Its main task request by a client is query request and E-Device control. CQA receives a query request from an event containing commands transmitted from DCI and a control request, and calls function necessary to respond each request. When clients request query, CQA forwards basic information on the query request to DQG. DQG creates Database search query based on the basic information and sends it to DP. DP enhances performance by implementing query optimization when received query has no error. Query optimization contains following steps: 1. Query Sort, 2. Query Disintegration, 3. Common query extraction and implementation, and 4. Query result integration. DP then searches Databases using optimized search query, and saves the result in XML document. The XML document is then sent to a client by XT. CQA calls a function in response to client’s control request. CP then extracts control command and E-Device to be control from a administrator. Control request verifies validity of command through RD and Rule DB. Verified command is then forwarded to QO, and QO finally implements E-Device control command. 4.1.3. State component State Component acquires, integrates, and analyzes collected Emergency information, and it is implemented when certain event is called. Fig. 8 shows the structure of State Component. State Component is composed of DCI (Data Communication Interface), DR (Data Receiver), DF (Data Filter), MR (MetaInfo Requester), SD (State Delimiter), SK (Storage Keeper), SR (State Repository). When an Emergency occurs in certain E-Device, EM (Emergency Module) calls State component. DR extract ID of the specific E-Device from data transmitted from EM, and sends the ID to MR and transmitted data to DF. DF then analyzes transmitted data and extracts data that are to be stored in database. MR uses E-Device ID to request meta information. Extracted data from DF and meta information from MR are sent to SD. When SD transmits events, SD divides the event into E-Device unit. SD then integrates event data from E-Device and EDevice’s meta information, and sends the result to SK. SK then saves E-Device-unit-divided data into SR. 4.2. GML map visualization and monitoring 4.2.1. GML map visualization GIS has been developed with multiple methods and forms in order to display, analyze, process, store, gain geographic information data. There exist shortcomings on free usage, integration, application, and sharing due to limited format of GIS; therefore, common interchangeable format is necessary. OGC has suggested a GML specification in order to save and transfer geographic information containing a geographic aspect that has spatial or non-spatial attributes. To provide interoperability of GIS, GML gives a structure to data allowing flexibility of an access to information. This paper visualizes and creates common-format GML that covers heterogeneity of geographic information data, supporting its interoperability [9–11]. Due to massive volume of geographic information data, performance improvement for visualizing the data onto mobile device is required. File formats such as DXF, DWG, and SHP that are currently used widely are visualized onto specific application. This section constructs Map Preprocessor maker that is a part of preprocessing containing expandability of a file format that provides fast access to server and deals with its heterogeneity. Map Preprocessor categorizes Importer modules by layer according map format, extracts their core elements, and reduces their weight and give them attributes. DXF/DWG Importer extracts geographic information data property of six sections of DXF and DWG formats. BLOCKS and ENTITIES sections
Fig. 7. Control-Query Component.
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Fig. 8. Structure of State Component.
are used when extracting physical information and analyzing through ENTITY Parser. ENTITY Parser makes symbols or marks used in BLOCKS section into groups. Grouped information is used when indicating buildings, farmlands, roads, or rivers, and it is displayed as INSERT in ENTITIES section. INSERT information uses group code layers defined in BLOCKS sections, and save them into Temp Block Data distinguishing from ENTITIES section. INSERT property generates Final Object adding coordinates defined in BLOCKS section onto coordinated defined in ENTITIES section. SHP brings shape information though File Importer and property information through DBF Importer. Shape information extracts Bounding Box which is maximum and minimum value of coordinates of main header from *.shp file, and defines area of a shape. Shape File Handler approaches to record contents in size of Content Length of record header and opens the contents. Record contents extract the contents according to types of the shapes at Shape Type Importer, and waits in order to match the contents with property information that is to be extracted from *.dbf files. DBF Importer reads *.dbf files and stores its property value into Shape Attribute Table. Shape Attribute Table matches its values with extracted shape information from Shape Type Importer and generates Final Object. Fig. 9 shows structure of DXF/DWG and SHP Importer module. Light-Weighted Module categorizes Final Object generated by DXF/DWG and SHP Importer into specific layers, thus reducing its weight – it refers to national geographic standard code when categorizing. Extracted layer code is in 4000 s (4000–4637) indicating buildings, 3000 s (3000–3999) indicating roads, and 9000 s (9110–9233) indicating texts. Fig. 10 shows a file extracted from DXF file of ‘‘3 Ga, Han-Ok Village, Pungnam dong, Wansan gu, JeonJu, JeonBuk, 560-033 Korea” by Map Preprocessor. GML Maker reconstructs geometry property and property information extracted by Map Preprocessor into GML document. Specific structure of GML Maker is described by Fig. 11. GML is displayed in different ways according to its map format. Attribute Converter changes data structure of heterogeneous geographic information in order to parse them into common GML format, and matches properties of Final Object and
Fig. 9. Map Preprocessor for DXF, DWG, and SHP.
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Fig. 10. DXF file and attributes of extracted by Map Preprocessor.
GeoMetricData. Referring to Attribute Define that had defined GML property tags, GML Document Maker provides methods that generate GML schemes and property elements. The generator method is composed of a generator method that deals with basic schemes such as defining NameSpace, generating property, starting tag, ending tag, CDATA configuration, and an element generator method that deals with polygonal properties of Geometry Types such as Polygon, Polyline, or Circle. GML Maker sorts Geometry Types by GeoMetricData, and calls out an element generator method and inserts it to basic scheme. FeatureMember generates GML with Exporter. GML Parser induced GML parsing through XML Parser, which enhances memory usage and CPU resource usage by SAX method. Among standard library modules provided by SAX, GML Parser inherits XMLParser class and defines GMLParser class. GMLParser class defines individual elements based on GML Schema, and calls out a handler that is defined as event-type form in order to process the individual elements. GMLParser class processes a tag with key and value of an element. The key is name of the tag, and the value is the name of function that will carry on starting and ending tag and is composed of tuple. For example, if the tag is hvgml id = ‘‘2”type = ‘‘simple”i, GMLParser class calls out vgml_start_tag[{‘id’:‘2’, ‘type’ = ‘simple’}]. Function is called out in following method: in case of starting tag, handle_starttag function is called out, and in case of ending tag, handle_endtag function is redefined and altered. GML parsing process should be explained by Fig. 12. 4.2.2. Trace monitoring Monitoring Module (MM) analyzes E-Device’s current situation by tracing its location when emergency call is called upon by NM. Fig. 13 displays detailed structure of Monitoring Module. MM is responsible for map visualization and realtime monitoring on emergency E-Devices. Map visualization selects certain range of X and Y coordinates on Area Selector, taking Emergency Location as the point of origin. FeatureMember Extractor then extracts FeatureMembers within the selected range by comparing selected range with origins or FeatureMembers, which are GML file’s independent objects. Extracted FeatureMembers then extract necessary attribute information for FeatureMember visualization through Geometry Parser, and create them as Map Objects thus providing foundation for map visualization. Map Object stores map information into system’s internal memory in order to provide faster visualization of moving device and easier standard maneuver of the map includ-
Fig. 11. Structure of GML maker.
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Fig. 12. GML parsing process.
Fig. 13. Structure of Monitoring Module.
ing expand and sizing. Map information stored in Map Object is visualized onto Map Viewer as selected area of map around the emergency device through Map Visualization Component Module which contains Draw methods for each figure. Location Updater stores and updates Emergency Location which is a set of location coordinates of the device that shows movement of the device after the emergency. As the devices’ location coordinates are updated in Location Updater, Moving Trace sends new coordinates to Event Manager, and Event Manager visualizes the new coordinates onto Map Viewer. Event Manager is a module located in between map visualization and trace monitoring, and it is responsible for re-visualization of the map according to user events such as sizing or moving of the map. It also re-visualizes the latest location coordinates of the device onto Map Viewer. 4.3. Emergency transmission EM sends E-Device user’s diagnosis and medical record to emergency institutions and transmits the emergency situation of the user to his/her guardian through SMS. The institutions then use the received information to provide adequate medical service to each patient. Fig. 14 shows detailed architecture of Emergency Module. EM’s function can be divided into two categories: emergency situation transmission and personal medical visualization. When emergency call is called upon from EDevice, EM traces the device’s location and transmits the information to emergency institutions and paramedics. Data Receiver receives emergency situation, and Query Processing sends device’s unique ID to Reasoning Engine in order to find appropriate institution or person. Reasoning Engine uses the unique ID to find adequate institutions or person from Repository. Searched data by Reasoning Engine are then sent to Emergency Calling component and SMS component through Data Sender. Emergency Calling Component transmits the situation to connected emergency institutions and calls for ambulance to designated area. SMS Component transmits the situation to emergency caller’s guardians or relatives; moreover, it analyzes paramedics’ schedule information and notifies them. Personal Medical Visualization receives personal information
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Fig. 14. Architecture of Emergency Module.
through Data Receiver. Query Processing then sends the personal information input to Reasoning Engine. Reasoning Engine uses the received information to extract the patient’s medical history and the most adequate medical institution from Repository. Personal Medical Visualization then visualizes the information received from Reasoning Engine using Viewer Component. 5. Performance evaluation with DEVS This section presents analysis of GML map processing with respect to Map Object based on offset value. We have evaluated data size and execution time of data with Map Object to compare the performance of three schemes presented in this section as followed; (1) primitive GML, (2) simple filtered GML Map Object, and (3) GML Map Object with offset value. For considering this analysis environment, we used the Map Object structure as shown in Fig. 15. Fig. 15 includes the definitions of GML, Filtering and Offset, which were used by performance evaluation as factors in this paper. In our experiments, primitive GML map data should be divided into active area size, which viewed on screen area. And we evaluated the ratio of primitive GML map data size to filtered and offset GML map data size in Fig. 16a. It should be noted that Y axis represents Kbyte for Fig. 16a. As we can see, offset GML has more good efficiency than filtered Map Object and primitive GML map data. Also, Fig. 16b shows that the execution time for processing and transmission of GML map data with respect to the primitive GML, the filtered GML and offset GML. DEVS (Discrete Event systems Specification) was formalized by Zeigler [12,13] as a system specification for discrete event models. It provides a basis for specifying models that are expressible in discrete event simulation languages. In this paper, we adapted structural and modular DEVS formalism for the trajectory of E-Device as GPS coordinate X, Y value: [Definition of DEVS formalism] A DEVS basic model DEVSM is a structure, DEVSM = hX, S, Y, dint, dext, k, tai
Object ID Factor
Center Serialization
Map Object
sendByteStream
Boundary Offset
Definition
GML
Primitive GML Map data
Filtering
Simple filtered GML map object
Offset
GML map object with offset value
GML Feature
FeatureNM
Center Coordinate
Geometry Type
Fig. 15. Map Object structure and performance evaluation factors.
Coordinates
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Fig. 16. Performance evaluation for GML map object.
Where, X: input events set, S: sequential state set, Y: output events set, dint: S ? S: internal transition function, dext: Q S ? S: external transition function, k: S ? Y: output function, ta: S ? Rþ 0;1 : time advanced function. where Q is the total state of M given by Q ¼ fðs; eÞjs 2 S and 0 6 e 6 ta(s)}, and if the model is in state s at time ti, it will remain in s until ti + ta(s) where ta(s) = min{ri|ri P 0}. DEVSM is a component of the model, which is affected by events X produced in the environment and which in turn produces events Y that affects the environment. The state s of the DEVSM is computed by the appropriate transition function: internal dint or external dext. In a discrete event simulation, an event is scheduled to occur in ta(s) time units. If an external event arrives at elapsed time e which is less than or equal to the ta(s) time units, then a new state s0 is computed by means of the external transition function dext and a new ta(s0 ) is also determined. The elapsed time e is reset 0. If no external event arrives, then the elapsed time e must be equal to ta(s) time units and a new state s0 is computed by means of the internal transition function dint. However, at an internal event, an output produced by DEVSM is computed by the output function lambda based on the state s of the DEVSM. In order to construct the model of active call emergency system, we adapted to DEVS formalism for getting the location of E-Device as followed: 1. X={/, e} where, e: emergency event 2. s = hr1, n, r2, ri where, r1, r2: probability variables r: emergency time left variable
Fig. 17. Performance evaluation for E-device location.
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Fig. 18. Calibration with map matching.
3. Y = {(xi, yj} |xi, yj 2 R+}, if emergency state = yes 4. ta(s) = r 5. dext(hr1, n, r2, ri, e, x) = hC1 (r1), n, r2, r ei where, e: the emergency elapsed time hr1 ; n; r 2 ; 1i 6. dint ðhr1 ; n; r 2 ; riÞ ¼ hr1 ; n; C2 ðr 2 Þ; emergency timeðr 2 Þi
if n 1 if n 2
7. k1 (s) = emergency state k2 (s) = n(2R+) where, C1, C2, emergency time: exponential The location of E-Device, which it has been called emergency, should be shown in Fig. 17a. It should be noted that X axis represents the emergency call time and Y axis represents the altitude of E-Device included GPS coordinate value X, Y and height value. Fig. 17a shows location of E-Device based on speed of mobility and altitude after E-Device when it has been called and GPS location information with TM coordinate value was shown in Fig. 17b. Yellow rectangle means that E-Device has not received the signal from the base station and red rectangle shows the status of secession of GPS location about EDevice momentarily. We got the GPS coordinate values of E-Device’s location after be called emergency with respect to steady state. We should consider the secession status of E-Device transiently when it cannot use calibration formula with GPS coordinate in shown Fig. 18a. The average error distance is 8.08 m between coordinate of GPS received signal and actual EDevice coordinate In Fig. 18b shows the location of E-Device with calibration by using map matching method between coordinate of GPS received signal and actual E-Device coordinate. 6. Implementation and its application Section 6 illustrates application of suggested system. The system is implemented by Java JDK 1.6 and visualization of system is a case of ‘part of Han-Ok, JeonJu, JeonBuk, Korea’, Fig. 19a is an initial execution which is not registered by E-Device. It
Fig. 19. Active emergency call system process screen.
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Fig. 20. Location trace monitoring with calibration.
Fig. 21. Origination of emergency calling.
recognizes road and building with colors. Around the section of map visualization, the menu (r) is on the top and monitoring icon is visualized with map realization window (s). The out-put is on the right and the system log (u) which is able to output all type of conditions in system. The menu of the menu bar is composed context management, device management, statistical analysis, system log, device information, add on device. Context management is automatically saved with emergency situation information in the data base when emergency situation occurs, and it can monitor or input processing situation about being saved. Device management provides the monitoring, the modification and the deletion of the all information in the registered device. Statistical analysis provides emergency situation statistic with a graph as date, time and region. System log output all type of situation and processing result in system. Device information presents hierarchical information of the device registered in system. And it offers individual information and control information of each device. System log, if the program was initialized about the device information, will be output on a monitor in condition of ‘ON’. But the condition is ‘OFF’, it is impossible for the wide screen to visualize system log and device information. The event icons of map visualization window is composed with an zoom in/out icon, a movement icon for moving and the View All menu option icon for looking the whole map. E-Device could be registered in Fig. 19b. It is possible to add device when you click to the button of addition device. Get extra user when you input about basic information for example choose local constituencies, region, act on the input window of the device addition information Fig. 20.
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Fig. 22. Validation based on WIPI emulator.
Fig. 21 is about the situation of origination of emergency context, representation to system log information and ACE system goes to automatic sending SMS service to the guardian of emergency service target and a emergency center. In this paper realization to the E-Device’s movement takes advantage of GPS log information on the WIPI environment, that information goes to system by TCP/IP and UDP also takes advantage of that each E-Device movement tracing condition visualization is the same as Fig. 21. Fig. 22 become synchronization between used each E-Device WIPI emulator and active emergency call system for validation.
7. Conclusion and future research This paper realized active emergency call system for automatic emergency call service. The major contributions of this system as followed; (1) it provides cheap service for the handicapped and the elders (2) we manufactured low-priced E-Device and (3) eliminating unnecessary service fees so that the primary consumers (the handicapped, the elders, and children) can easily access to emergency service and receive proper treatment through institutions and their guardians. (4) It also supported realtime monitoring function by using GML standard map visualization and location tracing mechanism in order to manage E-Devices. In additional, for importing DXF, DWG, SHP file as a basic numerical map files easily in Map Preprocessor, in this paper we filter and exclude the unnecessary parts in the existing format visible according to the tag and the attributes. Then, to import the filtered file based on Map Preprocessor and GML visualization capable of composing the basic geographic information of location trace monitoring rapidly and easily, the scale and map sheet is stored as clear numbers and each file can be made to manage uniquely. Active emergency call system is composed of two parts: E-Device which is designed in a way to be accessible to its primary consumers including the minorities including the handicapped, the elders, and children, and E-Server which manages E-Devices and active emergency situation response. E-Device is designed light-weighted to be portable. It uses GPS transmitter and widely-used CDMA Module for location tracing and easy communication. Active emergency call communication protocol is also constructed so that the device will communicate with the server once in every certain amount of time in order to reduce communication cost. E-Server is to trace and monitor situated E-Devices, and to transmit user’s information actively to emergency institutions and the user’s guardian. Trace monitoring supports expand and reuse of a map by visualizing standard GML-based map. EServer actively processes emergency situation signal so that the system would respond to the situation as quickly as possible. It also sends user’s medical history along with his/her location information to emergency institutions so that the institution can provide most optimal response to the patient; moreover, using SMS it reports the current status of the device user to his/ her guardian. And finally, we described performance evaluation of the location error of E-Device, which it has been called emergency by using DEVS formalism. For future research, status display window for E-Device may be developed so that users can comprehend the realtime process better in one simple display window. In case of absence of administrator to the E-Server, remote emergency call con-
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trol system may also be constructed, realizing true human-oriented u-Healthcare service for both users and administrators. For better location tracing in urban areas and for quicker response, the service may be developed to support Location Based Service, of which many organizations are currently developing. Acknowledgment This work was supported by the IT R&D program of MKE/KEIT. [10033915, Adaptive fusion technology for large-scale sensor node based intelligent surveillance system]. References [1] I. Biton, M. Koifman, I.Y. Bar-Itzhack, Improved direct solution of the global positioning system equation, Journal of Guidance, Control, and Dynamics 21 (1) (1998). [2] Julius O. Smith, Jonathan S. Abel, Closed-form least square source location estimation from range difference measurements, IEEE Transactions on Acoustics, Speech, and Signal Processing ASSP-35 (12) (1987). [3] I. Ziskind, M. Wax, Maximun likelihood localization of multiple sources by alternation projection, IEEE Transactions on Acoustics, Speech, and Signal Processing 36 (10) (1998) 1553–1560. [4] W.A. Gradner, C.K. Chen, Signal-selective time-difference-of arrival estimation for passive location of man-made signal sources in highly corruptive environments, Part 1: theory and method, IEEE Transactions on Signal Processing 40 (5) (1992) 1168–1184. [5] L.A. Stilp, Time difference of arrival technology for locating narrow-band cellura signals, in: SPIE Conference on Voice, Data, and Video Communication, Philadelphia, PA, October 1995. [6] P. Enge, P. Misra, Special issue on global positioning system, Proceedings of the IEEE 87 (1) (1999) 3–15. [7] R. Bajaj, S. Ranaweera, D.P. Agrawal, GPS: location-tracking technology, IEEE Computer 35 (4) (2002) 92–94. [8] W.H. Han, E.H. Song, L.T. Yang, J.H. Park, Y.S. Jeong, ACE: active emergence call service system for u-Lifecare, in: International Conference on Multimedia and Ubiquitous Engineering, 2008, pp.126–131. [9] Shashi Shekhar, Ranga Raju Vatsavai, Namita Sahay, Thomas E. Burk, Stephen Lime, GML, interoperability, and standards: WMS and GML based interoperable web mapping system, in: Proceedings of the ninth ACM International Symposium on Advances in Geographic Information Systems, 2001. [10] G. Laganathan, GPS and GIS technology 14 (6) (2002) 0292–0294. [11] E.H. Song, L.T. Yang, Y.S. Jeong, Visualization of GML Map using 3-layer POI on mobile device, in: International Conference on Embedded Software and System, 2007, pp. 328–337. [12] B.P. Zeigler, System-theoretic representation of simulation models, IIE Transactions Industrial Engineering Research and Development 16 (1) (1984) 19–34. [13] B.P. Zeigler, Theory of Modelling and Simulation, A Wiley Interscience Publication, 1984.
Contents lists available at ScienceDirect
Simulation Modelling Practice and Theory journal homepage: www.elsevier.com/locate/simpat
Performance evaluation with DEVS formalism and implementation of active emergency call system for realtime location and monitoring Young-Sik Jeong a,*, Won-Hee Han a, Eun-Ha Song a, Sang-Soo Yeo b a b
Department of Computer Engineering, Wonkwang University, Republic of Korea Division of Computer Engineering, Mokwon University, Republic of Korea
a r t i c l e
i n f o
Article history: Available online 17 September 2009 Keywords: LBS (Location Based Services) GPS (Global Positioning System) Realtime monitoring DEVS (Discrete Event System Specification) Object location tracing
a b s t r a c t In this paper, we designed and implemented the active emergency call system for emergency call service actively. Active emergency call system has two physical components; E-Device (Emergency Mobile Device) and E-Server (Emergency Server). The role of EDevice is the mobile device in order to call emergency by using mild handicapped, the elderly and children who are able to communicate their intention to another. E-Server is the server for management E-Devices with realtime monitoring. E-Device will be developed to the portable size for easily mild handicapped, the elderly and children. When they need the service of emergency call, the button of E-Device can be used and the call signal is transmitted to the emergency office and the guardian through Internet and CDMA. E-Server should be developed the integrated control system for management of E-Devices basically. And it also supported to realtime monitoring of E-Devices with respect to high quality of emergency call service for rise the efficiency. And finally we describe the results of performance evaluation about the location error of E-Device between coordinate of GPS received signal and actual E-Device coordinate, when it has been called emergency, by using DEVS (Discrete Event System Specification) formalism. Ó 2009 Elsevier B.V. All rights reserved.
1. Introduction Due to recent development in ubiquitous technology, location information technology service is being used in various fields in real life. u-Lifecare system, utilizes location information service technology to locate the handicapped, the elders, or missing children. Nevertheless, most of recent u-Healthcare location information services are established overly dependent on certain type of communication network environment; moreover, there are many services with similar characteristics that are not compatible with each other thus creating overlapping services. In establishing alarming system, existing uHealthcare system can only provide emergency call and the simplest information on the patient’s location, and cannot provide adequate treatment. In other words, current u-Healthcare location tracing system and emergency service system lack active service call mechanism that is proper for different patients. This paper develops active emergency call system, an emergency call service system for the minorities including the handicapped, elders, and children. Active emergency call system is composed of two components: E-Device and E-Server. E-Device, in emergency situations, actively sends signal to emergency institutions and guardians, and requests help through wire and/or wireless network. E-Device is designed in such way that it is portable and easy to use due to special characteristics of its primary consumers. And to conclude for efficient service, it should provide cheap and low-cost service for the handicapped and the elders. We manufacture low-priced E-Device and support eliminating unnecessary service fees so that * Corresponding author. Tel.: +82 63 850 6746; fax: +82 63 856 8009. E-mail addresses: [email protected] (Y.-S. Jeong), [email protected] (W.-H. Han), [email protected] (E.-H. Song), [email protected] (S.-S. Yeo). 1569-190X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.simpat.2009.09.006
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the primary consumers (the handicapped, the elders, and children) can easily access to emergency service and receive proper treatment through institutions and their guardians. It also supported realtime monitoring function by using GML standard map visualization and location tracing mechanism in order to manage E-Devices. And finally we show the results of performance evaluation for the location error of E-Device between coordinate of GPS received signal and actual E-Device coordinate, when it has been called emergency, by using DEVS (Discrete Event System Specification) formalism. E-Server is designed for comprehensive management of all the E-Devices and related emergency calls. E-Server locates and visualizes situated E-Device in realtime, and actively forwards emergency information to emergency institutions and patient’s guardian. When the emergency call button on the E-Device is pressed, location information of E-Device is collected by active emergency call system through GPS satellite, emergency calls are forwarded to E-Server through CDMA, and the specific information is sent to emergency institutions and guardians through SMS by E-Server. When active emergency call system receives emergency call signal, it traces location of the patient in realtime through realtime emergency situation monitoring. It also sends the realtime information to institutions and guardians through SMS.
2. Related works There are several existing location information services: myPol by KLIC Ltd., Emergency Help Service by icarefree Co., SOS Service by SK Telecom, E-Call Service by Europe and ACMA by Australia. It uses TDOA technique to locate mobile station by calculating the time difference between local trans-receiver and the mobile station [1,2]. In order to locate local trans-receiver in exact, one or more TDOA values are needed; therefore, in order to utilize myPol service, great number of trans-receiver must be installed in wide range of areas, thus resulting in expensive budget [3–5]. icarefree’s Emergency Help Service and SOS Service by SK Telecom both utilize GPS for location tracing. GPS operates on 24 NAVSTAR (Navigation System with Time and Ranging) satellites; each four satellites are allocated into six different circular orbital surfaces on 20,183 km altitude, acquiring information on latitude, longitude, altitude, even velocity and time information [6]. GPS uses trigonometry to calculate location [7]; therefore, it leaves wide error range when calculating location in urban areas. E-Call by Europe, which has GPS and mobile communication technology functions, is transferring circumstance of Car’s accident as message to each station. ACMA Service by Australia is providing local information and emergency situation by local telephone and mobile phone. Those systems use existing CDMA network, so it requires relatively small initial capital. There are various location information services other than suggested existing services; however, most of them require expensive equipments, and additional service fees are required as well. Active emergency call system provides cheap service using low-priced device and eliminating unnecessary service fees so that the primary consumers (the handicapped, the elders, and children) can easily access to emergency service and receive proper treatment through institutions and their guardians. Active emergency call system uses realtime monitoring technique using GML standard map visualization and location tracing mechanism in order to manage E-Devices.
3. Active emergency call system The Active emergency call system is composed of E-Device, E-Server, and software for emergency institutions. E-Device collects location information from GPS satellite, and sends the location information with its own data to E-Server through CDMA network when emergency call button is pressed. E-Server collects personal information, the user’s location information, and the user’s guardian information, and sends the information to emergency institutions and guardians while running realtime location trace monitoring on the device. The software displays received location information and medical history of the patient. Fig. 1 shows overall operation environment of active emergency call system [8]. 3.1. E-Device E-Device is active emergency call system’s portable device sending emergency signals. As shown in Fig. 2, E-Device is composed of three parts: CDMA Module for communicating with active emergency call system’s server, GPS Module for locating the device’s location, and Process Module which executes emergency call routine. Qualcomm’s MSM6025 is used for CDMA Module. It is a wireless CDMA200 1X internal modem in 800 MHz range that has voice/data transmitting feature connecting to CMDA wireless network. It receives transmitted data from Process Module through UART 1 running Atmega 128 HOST and RS-232 Serial Communication, and transmits the data to E-Server. GPS Module amplifies transmitted signal from GPS satellite through two steps and eliminates noises using SAW Filter and Line Filter. Amplified and processed signal is then transmitted from GPS RF Front END (GRF3i/LP) to GPS Engine Processor (GSP2e/LP). GPS Engine Processor then transmits the signal to Process Module through RS-232 Serial Communication in string form. Process Module is a MicroProcessor, responsible for actual calculations. It uses two UARTs and communicates between CDMA Module and GPS Module. UART 0 has 115,200 bps transmitting speed and operates CDMA Module and its communication; UART 1 receives RS-232 string data from GPS Module. Process Module’s External Interrupt is connected to emergency call button, so when the button is pressed External Interrupt runs emergency call routine. When emergency call routine is
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Fig. 1. Operation environment of active emergency call system.
Fig. 2. E-Device structure and components.
called upon, it is connected to designated gateway through CDMA, and transmitted coordinates from GPS Module and the device’s unique ID are transmitted in string form. 3.2. E-Server E-Server is active emergency call system’s main server for comprehensive management of E-Devices and adequate response for emergency situations. E-Server is composed of various components: CM (Communication Module) which enables two-way communication with E-Server, SP (Signal Processor) which extracts data from E-Device by analyzing signals transmitted through CDMA network, NM (Network Module) which manages devices’ location by analyzing extracted data from SP, MM (Monitoring Module) which is responsible for realtime location tracing and monitoring visualization, EM (Emergency Module) which notifies the emergency situation to emergency institutions and guardians, and Database that stores patient’s personal information and medical information. Fig. 3 shows detailed structure of E-Server.
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3.3. Emergency Call Scenario and Emergency Call Protocol When emergency situation occurs, E-Device sends emergency call to E-Server, and when ACK Message is received from the server, E-Device sends its location information periodically to the server in order to reduce communication cost. When Emergency call is sent from the E-Device, E-Server then analyzes the device’s location information and its ID through Signal Processor. Emergency Module meanwhile connects to DB, downloads user’s personal information and medical history, and makes emergency call to Emergency Center. Monitoring Module monitors device’s location status and emergency response process from the beginning to end of the situation. Fig. 4 shows active emergency call system’s service scenario and communication protocol. 4. Realtime location and monitoring 4.1. Location management Network Module (NM) constantly manages E-Device’s location and sends emergency signals. It also manages E-Devices’ network. Fig. 5 shows detailed component structure of NM. NM is composed of three components: Data Management, VO (Virtual Organization) Information, and Location Contact. Data Management component analyzes, processes, and stores the data from SP. Event Dispatcher sends the data to related components, and Event Extraction extracts the data from Event Dispatcher and divides them into two categories: data to be stored in the DB, and events to be processed. Extracted data are stored in Data Repository/Query Repository through Query Processing. VO Information component analyzes network information to which E-Device is connected. When a network event is created by Event Extraction, Processing Filtering extracts network information from the storage. Extracted network data is then sent to VO Information component through Event Dispatcher, and VO Information visualizes the data onto the administrator system. Location Contact component receives extracted E-Device’s location information by Data Management from Event Dispatcher and stores them at Location DB. 4.1.1. Meta Information Component Meta Information Component requests hardware information on E-Device from administrator, and saves the creation information in meta information management DB. Fig. 6 shows the specific structure of Meta Information Component. Meta Information Component is consisted of several components: DCI (Data Communication Interface), CA (Command Analyzer), SE (Search Engine), MM (MetaInfo Maker), XG (XML Generator), XT (XML Transmitter), and MetaInfo DB. When client implements Meta info-related event, the event itself transmits a command event from Meta info scheme through DCI. The command event received by DCI analyzes the event, of which the administrator is to implement, through CA. Using the analysis result, the command event then searches meta info related data, and calls corresponding command by determining whether the search data is a new meta information input or not. When a command for new information input on meta information is requested, a administrator calls MM. MM analyzes meta information-related XML data transmitted from a administrator, and inputs the result in E-Device DB. When a client request meta information data, MM creates E-Device DB search query through SE, and searches E-Device DB based on the created query. XG creates XML document containing data search result through SE. XT then forwards created XML documents to the administrator that initially requested command implementation through DCI.
Fig. 3. E-Server structure.
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Fig. 4. Service scenario and communication protocol of active emergency call system.
Fig. 5. Network Module for location management of E-Device.
Fig. 6. Meta Information Component.
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4.1.2. Control-Query Component Control-Query Component controls E-Device and it request Database information such as E-Device control command, user information, E-Device installation information, and so on. Fig. 7 shows Control-Query Component’s specific architecture. Control-Query Component is composed of several components: DCI (Data Communication Interface), CQA (Control and Query Analyzer), DQG (Database Query Generator), DP (Databases Processor), XT (XML Transmitter), CP (Context Provider), RD (Rule Discriminator), RE (Reasoning Engine), QO (Query Operator), and Database. Its main task request by a client is query request and E-Device control. CQA receives a query request from an event containing commands transmitted from DCI and a control request, and calls function necessary to respond each request. When clients request query, CQA forwards basic information on the query request to DQG. DQG creates Database search query based on the basic information and sends it to DP. DP enhances performance by implementing query optimization when received query has no error. Query optimization contains following steps: 1. Query Sort, 2. Query Disintegration, 3. Common query extraction and implementation, and 4. Query result integration. DP then searches Databases using optimized search query, and saves the result in XML document. The XML document is then sent to a client by XT. CQA calls a function in response to client’s control request. CP then extracts control command and E-Device to be control from a administrator. Control request verifies validity of command through RD and Rule DB. Verified command is then forwarded to QO, and QO finally implements E-Device control command. 4.1.3. State component State Component acquires, integrates, and analyzes collected Emergency information, and it is implemented when certain event is called. Fig. 8 shows the structure of State Component. State Component is composed of DCI (Data Communication Interface), DR (Data Receiver), DF (Data Filter), MR (MetaInfo Requester), SD (State Delimiter), SK (Storage Keeper), SR (State Repository). When an Emergency occurs in certain E-Device, EM (Emergency Module) calls State component. DR extract ID of the specific E-Device from data transmitted from EM, and sends the ID to MR and transmitted data to DF. DF then analyzes transmitted data and extracts data that are to be stored in database. MR uses E-Device ID to request meta information. Extracted data from DF and meta information from MR are sent to SD. When SD transmits events, SD divides the event into E-Device unit. SD then integrates event data from E-Device and EDevice’s meta information, and sends the result to SK. SK then saves E-Device-unit-divided data into SR. 4.2. GML map visualization and monitoring 4.2.1. GML map visualization GIS has been developed with multiple methods and forms in order to display, analyze, process, store, gain geographic information data. There exist shortcomings on free usage, integration, application, and sharing due to limited format of GIS; therefore, common interchangeable format is necessary. OGC has suggested a GML specification in order to save and transfer geographic information containing a geographic aspect that has spatial or non-spatial attributes. To provide interoperability of GIS, GML gives a structure to data allowing flexibility of an access to information. This paper visualizes and creates common-format GML that covers heterogeneity of geographic information data, supporting its interoperability [9–11]. Due to massive volume of geographic information data, performance improvement for visualizing the data onto mobile device is required. File formats such as DXF, DWG, and SHP that are currently used widely are visualized onto specific application. This section constructs Map Preprocessor maker that is a part of preprocessing containing expandability of a file format that provides fast access to server and deals with its heterogeneity. Map Preprocessor categorizes Importer modules by layer according map format, extracts their core elements, and reduces their weight and give them attributes. DXF/DWG Importer extracts geographic information data property of six sections of DXF and DWG formats. BLOCKS and ENTITIES sections
Fig. 7. Control-Query Component.
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Fig. 8. Structure of State Component.
are used when extracting physical information and analyzing through ENTITY Parser. ENTITY Parser makes symbols or marks used in BLOCKS section into groups. Grouped information is used when indicating buildings, farmlands, roads, or rivers, and it is displayed as INSERT in ENTITIES section. INSERT information uses group code layers defined in BLOCKS sections, and save them into Temp Block Data distinguishing from ENTITIES section. INSERT property generates Final Object adding coordinates defined in BLOCKS section onto coordinated defined in ENTITIES section. SHP brings shape information though File Importer and property information through DBF Importer. Shape information extracts Bounding Box which is maximum and minimum value of coordinates of main header from *.shp file, and defines area of a shape. Shape File Handler approaches to record contents in size of Content Length of record header and opens the contents. Record contents extract the contents according to types of the shapes at Shape Type Importer, and waits in order to match the contents with property information that is to be extracted from *.dbf files. DBF Importer reads *.dbf files and stores its property value into Shape Attribute Table. Shape Attribute Table matches its values with extracted shape information from Shape Type Importer and generates Final Object. Fig. 9 shows structure of DXF/DWG and SHP Importer module. Light-Weighted Module categorizes Final Object generated by DXF/DWG and SHP Importer into specific layers, thus reducing its weight – it refers to national geographic standard code when categorizing. Extracted layer code is in 4000 s (4000–4637) indicating buildings, 3000 s (3000–3999) indicating roads, and 9000 s (9110–9233) indicating texts. Fig. 10 shows a file extracted from DXF file of ‘‘3 Ga, Han-Ok Village, Pungnam dong, Wansan gu, JeonJu, JeonBuk, 560-033 Korea” by Map Preprocessor. GML Maker reconstructs geometry property and property information extracted by Map Preprocessor into GML document. Specific structure of GML Maker is described by Fig. 11. GML is displayed in different ways according to its map format. Attribute Converter changes data structure of heterogeneous geographic information in order to parse them into common GML format, and matches properties of Final Object and
Fig. 9. Map Preprocessor for DXF, DWG, and SHP.
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Fig. 10. DXF file and attributes of extracted by Map Preprocessor.
GeoMetricData. Referring to Attribute Define that had defined GML property tags, GML Document Maker provides methods that generate GML schemes and property elements. The generator method is composed of a generator method that deals with basic schemes such as defining NameSpace, generating property, starting tag, ending tag, CDATA configuration, and an element generator method that deals with polygonal properties of Geometry Types such as Polygon, Polyline, or Circle. GML Maker sorts Geometry Types by GeoMetricData, and calls out an element generator method and inserts it to basic scheme. FeatureMember generates GML with Exporter. GML Parser induced GML parsing through XML Parser, which enhances memory usage and CPU resource usage by SAX method. Among standard library modules provided by SAX, GML Parser inherits XMLParser class and defines GMLParser class. GMLParser class defines individual elements based on GML Schema, and calls out a handler that is defined as event-type form in order to process the individual elements. GMLParser class processes a tag with key and value of an element. The key is name of the tag, and the value is the name of function that will carry on starting and ending tag and is composed of tuple. For example, if the tag is hvgml id = ‘‘2”type = ‘‘simple”i, GMLParser class calls out vgml_start_tag[{‘id’:‘2’, ‘type’ = ‘simple’}]. Function is called out in following method: in case of starting tag, handle_starttag function is called out, and in case of ending tag, handle_endtag function is redefined and altered. GML parsing process should be explained by Fig. 12. 4.2.2. Trace monitoring Monitoring Module (MM) analyzes E-Device’s current situation by tracing its location when emergency call is called upon by NM. Fig. 13 displays detailed structure of Monitoring Module. MM is responsible for map visualization and realtime monitoring on emergency E-Devices. Map visualization selects certain range of X and Y coordinates on Area Selector, taking Emergency Location as the point of origin. FeatureMember Extractor then extracts FeatureMembers within the selected range by comparing selected range with origins or FeatureMembers, which are GML file’s independent objects. Extracted FeatureMembers then extract necessary attribute information for FeatureMember visualization through Geometry Parser, and create them as Map Objects thus providing foundation for map visualization. Map Object stores map information into system’s internal memory in order to provide faster visualization of moving device and easier standard maneuver of the map includ-
Fig. 11. Structure of GML maker.
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Fig. 12. GML parsing process.
Fig. 13. Structure of Monitoring Module.
ing expand and sizing. Map information stored in Map Object is visualized onto Map Viewer as selected area of map around the emergency device through Map Visualization Component Module which contains Draw methods for each figure. Location Updater stores and updates Emergency Location which is a set of location coordinates of the device that shows movement of the device after the emergency. As the devices’ location coordinates are updated in Location Updater, Moving Trace sends new coordinates to Event Manager, and Event Manager visualizes the new coordinates onto Map Viewer. Event Manager is a module located in between map visualization and trace monitoring, and it is responsible for re-visualization of the map according to user events such as sizing or moving of the map. It also re-visualizes the latest location coordinates of the device onto Map Viewer. 4.3. Emergency transmission EM sends E-Device user’s diagnosis and medical record to emergency institutions and transmits the emergency situation of the user to his/her guardian through SMS. The institutions then use the received information to provide adequate medical service to each patient. Fig. 14 shows detailed architecture of Emergency Module. EM’s function can be divided into two categories: emergency situation transmission and personal medical visualization. When emergency call is called upon from EDevice, EM traces the device’s location and transmits the information to emergency institutions and paramedics. Data Receiver receives emergency situation, and Query Processing sends device’s unique ID to Reasoning Engine in order to find appropriate institution or person. Reasoning Engine uses the unique ID to find adequate institutions or person from Repository. Searched data by Reasoning Engine are then sent to Emergency Calling component and SMS component through Data Sender. Emergency Calling Component transmits the situation to connected emergency institutions and calls for ambulance to designated area. SMS Component transmits the situation to emergency caller’s guardians or relatives; moreover, it analyzes paramedics’ schedule information and notifies them. Personal Medical Visualization receives personal information
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Fig. 14. Architecture of Emergency Module.
through Data Receiver. Query Processing then sends the personal information input to Reasoning Engine. Reasoning Engine uses the received information to extract the patient’s medical history and the most adequate medical institution from Repository. Personal Medical Visualization then visualizes the information received from Reasoning Engine using Viewer Component. 5. Performance evaluation with DEVS This section presents analysis of GML map processing with respect to Map Object based on offset value. We have evaluated data size and execution time of data with Map Object to compare the performance of three schemes presented in this section as followed; (1) primitive GML, (2) simple filtered GML Map Object, and (3) GML Map Object with offset value. For considering this analysis environment, we used the Map Object structure as shown in Fig. 15. Fig. 15 includes the definitions of GML, Filtering and Offset, which were used by performance evaluation as factors in this paper. In our experiments, primitive GML map data should be divided into active area size, which viewed on screen area. And we evaluated the ratio of primitive GML map data size to filtered and offset GML map data size in Fig. 16a. It should be noted that Y axis represents Kbyte for Fig. 16a. As we can see, offset GML has more good efficiency than filtered Map Object and primitive GML map data. Also, Fig. 16b shows that the execution time for processing and transmission of GML map data with respect to the primitive GML, the filtered GML and offset GML. DEVS (Discrete Event systems Specification) was formalized by Zeigler [12,13] as a system specification for discrete event models. It provides a basis for specifying models that are expressible in discrete event simulation languages. In this paper, we adapted structural and modular DEVS formalism for the trajectory of E-Device as GPS coordinate X, Y value: [Definition of DEVS formalism] A DEVS basic model DEVSM is a structure, DEVSM = hX, S, Y, dint, dext, k, tai
Object ID Factor
Center Serialization
Map Object
sendByteStream
Boundary Offset
Definition
GML
Primitive GML Map data
Filtering
Simple filtered GML map object
Offset
GML map object with offset value
GML Feature
FeatureNM
Center Coordinate
Geometry Type
Fig. 15. Map Object structure and performance evaluation factors.
Coordinates
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Fig. 16. Performance evaluation for GML map object.
Where, X: input events set, S: sequential state set, Y: output events set, dint: S ? S: internal transition function, dext: Q S ? S: external transition function, k: S ? Y: output function, ta: S ? Rþ 0;1 : time advanced function. where Q is the total state of M given by Q ¼ fðs; eÞjs 2 S and 0 6 e 6 ta(s)}, and if the model is in state s at time ti, it will remain in s until ti + ta(s) where ta(s) = min{ri|ri P 0}. DEVSM is a component of the model, which is affected by events X produced in the environment and which in turn produces events Y that affects the environment. The state s of the DEVSM is computed by the appropriate transition function: internal dint or external dext. In a discrete event simulation, an event is scheduled to occur in ta(s) time units. If an external event arrives at elapsed time e which is less than or equal to the ta(s) time units, then a new state s0 is computed by means of the external transition function dext and a new ta(s0 ) is also determined. The elapsed time e is reset 0. If no external event arrives, then the elapsed time e must be equal to ta(s) time units and a new state s0 is computed by means of the internal transition function dint. However, at an internal event, an output produced by DEVSM is computed by the output function lambda based on the state s of the DEVSM. In order to construct the model of active call emergency system, we adapted to DEVS formalism for getting the location of E-Device as followed: 1. X={/, e} where, e: emergency event 2. s = hr1, n, r2, ri where, r1, r2: probability variables r: emergency time left variable
Fig. 17. Performance evaluation for E-device location.
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Fig. 18. Calibration with map matching.
3. Y = {(xi, yj} |xi, yj 2 R+}, if emergency state = yes 4. ta(s) = r 5. dext(hr1, n, r2, ri, e, x) = hC1 (r1), n, r2, r ei where, e: the emergency elapsed time hr1 ; n; r 2 ; 1i 6. dint ðhr1 ; n; r 2 ; riÞ ¼ hr1 ; n; C2 ðr 2 Þ; emergency timeðr 2 Þi
if n 1 if n 2
7. k1 (s) = emergency state k2 (s) = n(2R+) where, C1, C2, emergency time: exponential The location of E-Device, which it has been called emergency, should be shown in Fig. 17a. It should be noted that X axis represents the emergency call time and Y axis represents the altitude of E-Device included GPS coordinate value X, Y and height value. Fig. 17a shows location of E-Device based on speed of mobility and altitude after E-Device when it has been called and GPS location information with TM coordinate value was shown in Fig. 17b. Yellow rectangle means that E-Device has not received the signal from the base station and red rectangle shows the status of secession of GPS location about EDevice momentarily. We got the GPS coordinate values of E-Device’s location after be called emergency with respect to steady state. We should consider the secession status of E-Device transiently when it cannot use calibration formula with GPS coordinate in shown Fig. 18a. The average error distance is 8.08 m between coordinate of GPS received signal and actual EDevice coordinate In Fig. 18b shows the location of E-Device with calibration by using map matching method between coordinate of GPS received signal and actual E-Device coordinate. 6. Implementation and its application Section 6 illustrates application of suggested system. The system is implemented by Java JDK 1.6 and visualization of system is a case of ‘part of Han-Ok, JeonJu, JeonBuk, Korea’, Fig. 19a is an initial execution which is not registered by E-Device. It
Fig. 19. Active emergency call system process screen.
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Fig. 20. Location trace monitoring with calibration.
Fig. 21. Origination of emergency calling.
recognizes road and building with colors. Around the section of map visualization, the menu (r) is on the top and monitoring icon is visualized with map realization window (s). The out-put is on the right and the system log (u) which is able to output all type of conditions in system. The menu of the menu bar is composed context management, device management, statistical analysis, system log, device information, add on device. Context management is automatically saved with emergency situation information in the data base when emergency situation occurs, and it can monitor or input processing situation about being saved. Device management provides the monitoring, the modification and the deletion of the all information in the registered device. Statistical analysis provides emergency situation statistic with a graph as date, time and region. System log output all type of situation and processing result in system. Device information presents hierarchical information of the device registered in system. And it offers individual information and control information of each device. System log, if the program was initialized about the device information, will be output on a monitor in condition of ‘ON’. But the condition is ‘OFF’, it is impossible for the wide screen to visualize system log and device information. The event icons of map visualization window is composed with an zoom in/out icon, a movement icon for moving and the View All menu option icon for looking the whole map. E-Device could be registered in Fig. 19b. It is possible to add device when you click to the button of addition device. Get extra user when you input about basic information for example choose local constituencies, region, act on the input window of the device addition information Fig. 20.
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Fig. 22. Validation based on WIPI emulator.
Fig. 21 is about the situation of origination of emergency context, representation to system log information and ACE system goes to automatic sending SMS service to the guardian of emergency service target and a emergency center. In this paper realization to the E-Device’s movement takes advantage of GPS log information on the WIPI environment, that information goes to system by TCP/IP and UDP also takes advantage of that each E-Device movement tracing condition visualization is the same as Fig. 21. Fig. 22 become synchronization between used each E-Device WIPI emulator and active emergency call system for validation.
7. Conclusion and future research This paper realized active emergency call system for automatic emergency call service. The major contributions of this system as followed; (1) it provides cheap service for the handicapped and the elders (2) we manufactured low-priced E-Device and (3) eliminating unnecessary service fees so that the primary consumers (the handicapped, the elders, and children) can easily access to emergency service and receive proper treatment through institutions and their guardians. (4) It also supported realtime monitoring function by using GML standard map visualization and location tracing mechanism in order to manage E-Devices. In additional, for importing DXF, DWG, SHP file as a basic numerical map files easily in Map Preprocessor, in this paper we filter and exclude the unnecessary parts in the existing format visible according to the tag and the attributes. Then, to import the filtered file based on Map Preprocessor and GML visualization capable of composing the basic geographic information of location trace monitoring rapidly and easily, the scale and map sheet is stored as clear numbers and each file can be made to manage uniquely. Active emergency call system is composed of two parts: E-Device which is designed in a way to be accessible to its primary consumers including the minorities including the handicapped, the elders, and children, and E-Server which manages E-Devices and active emergency situation response. E-Device is designed light-weighted to be portable. It uses GPS transmitter and widely-used CDMA Module for location tracing and easy communication. Active emergency call communication protocol is also constructed so that the device will communicate with the server once in every certain amount of time in order to reduce communication cost. E-Server is to trace and monitor situated E-Devices, and to transmit user’s information actively to emergency institutions and the user’s guardian. Trace monitoring supports expand and reuse of a map by visualizing standard GML-based map. EServer actively processes emergency situation signal so that the system would respond to the situation as quickly as possible. It also sends user’s medical history along with his/her location information to emergency institutions so that the institution can provide most optimal response to the patient; moreover, using SMS it reports the current status of the device user to his/ her guardian. And finally, we described performance evaluation of the location error of E-Device, which it has been called emergency by using DEVS formalism. For future research, status display window for E-Device may be developed so that users can comprehend the realtime process better in one simple display window. In case of absence of administrator to the E-Server, remote emergency call con-
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trol system may also be constructed, realizing true human-oriented u-Healthcare service for both users and administrators. For better location tracing in urban areas and for quicker response, the service may be developed to support Location Based Service, of which many organizations are currently developing. Acknowledgment This work was supported by the IT R&D program of MKE/KEIT. [10033915, Adaptive fusion technology for large-scale sensor node based intelligent surveillance system]. References [1] I. Biton, M. Koifman, I.Y. Bar-Itzhack, Improved direct solution of the global positioning system equation, Journal of Guidance, Control, and Dynamics 21 (1) (1998). [2] Julius O. Smith, Jonathan S. Abel, Closed-form least square source location estimation from range difference measurements, IEEE Transactions on Acoustics, Speech, and Signal Processing ASSP-35 (12) (1987). [3] I. Ziskind, M. Wax, Maximun likelihood localization of multiple sources by alternation projection, IEEE Transactions on Acoustics, Speech, and Signal Processing 36 (10) (1998) 1553–1560. [4] W.A. Gradner, C.K. Chen, Signal-selective time-difference-of arrival estimation for passive location of man-made signal sources in highly corruptive environments, Part 1: theory and method, IEEE Transactions on Signal Processing 40 (5) (1992) 1168–1184. [5] L.A. Stilp, Time difference of arrival technology for locating narrow-band cellura signals, in: SPIE Conference on Voice, Data, and Video Communication, Philadelphia, PA, October 1995. [6] P. Enge, P. Misra, Special issue on global positioning system, Proceedings of the IEEE 87 (1) (1999) 3–15. [7] R. Bajaj, S. Ranaweera, D.P. Agrawal, GPS: location-tracking technology, IEEE Computer 35 (4) (2002) 92–94. [8] W.H. Han, E.H. Song, L.T. Yang, J.H. Park, Y.S. Jeong, ACE: active emergence call service system for u-Lifecare, in: International Conference on Multimedia and Ubiquitous Engineering, 2008, pp.126–131. [9] Shashi Shekhar, Ranga Raju Vatsavai, Namita Sahay, Thomas E. Burk, Stephen Lime, GML, interoperability, and standards: WMS and GML based interoperable web mapping system, in: Proceedings of the ninth ACM International Symposium on Advances in Geographic Information Systems, 2001. [10] G. Laganathan, GPS and GIS technology 14 (6) (2002) 0292–0294. [11] E.H. Song, L.T. Yang, Y.S. Jeong, Visualization of GML Map using 3-layer POI on mobile device, in: International Conference on Embedded Software and System, 2007, pp. 328–337. [12] B.P. Zeigler, System-theoretic representation of simulation models, IIE Transactions Industrial Engineering Research and Development 16 (1) (1984) 19–34. [13] B.P. Zeigler, Theory of Modelling and Simulation, A Wiley Interscience Publication, 1984.