• Spatial Information Research
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• v.16 no.2
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• pp.157-171
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• 2008

With emerging technologies on wireless networks and mobile computing environment, a number of researches have been carried out for ubiquitous computing. An important functional requirement of ubiquitous computing is to handle location data with ease. With the increase of accidents in large complex buildings. move attention is being paid to indoor spaces and evacuation. However, most currently used evacuation-related applications are simulation based on hypothetical data. Also, since they use non-georeferenced CAD data, it is not easy to integrate them with indoor positioning devices. With the recent progress of indoor positioning systems, the simulators can be enhanced to real-time evacuation systems. As a preliminary stage to make such systems possible, this study proposes using a georeferenced data and evacuation simulation. This study used GIS data and Cellular Automata theory an the algorithm for the movement of the evacuee.

• Journal of ILASS-Korea
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• v.23 no.2
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• pp.81-89
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• 2018

The objective of this study is to estimate the level of exposure of traffic-related air pollutants (TRAPs) on the pedestrians in Seoul area. The road network's link-based pollutant emission was calculated by using a set of mobile source emission factor package and associated activity information. The population information, which is the number of pedestrian, was analyzed in conjunction with the link-based traffic emissions in order to quantify exposure level by selected 23 spots. We proposed the Exposure Intensity, which is defined by the amount of traffic emission and the population, to quantify the probability of exposure of pedestrian. Link-based traffic NOx and PM emissions vary by up to four times depending on the location of each spot. The Hot-spots is estimated to be around 1.8 times higher Exposure Intensity than the average of the 23 selected spots. The information of Exposure Intensity of each spot allows us to develop localized policies for air quality and health. Even in the same area, the Exposure Intensity over time also shows a large fluctuation, which gives suggestions for establishing site-specific counter-measures.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.3
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• pp.83-89
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• 2010

Scalable routing is one of the key challenges in designing and operating large scale MANETs. Performance of routing protocols proposed so far is only guaranteed under various limitation, i.e., dependent of the number of nodes in the network or needs the location information of destination node. Due to the dependency to the number of nodes in the network, as the number of nodes increases the performance of previous routing protocols degrade dramatically. We propose Cluster Overlay Dynamic Source Routing (CODSR) protocol. We conduct performance analysis by means of computer simulation under various conditions - diameter scaling and density scaling. Developed algorithm outperforms the DSR algorithm, e.g., more than 90% improvement as for the normalized routing load. Operation of CODSR is very simple and we show that the message and time complexity of CODSR is independent of the number of nodes in the network which makes CODSR highly scalable.

• Journal of the Korean Data and Information Science Society
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• v.21 no.6
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• pp.1155-1169
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• 2010

This study considers movement-based registration (MBR). In MBR, a mobile station (MS) performs location registration whenever the number of entering cells reaches the specified movement threshold M. MBR is simple and its implementation is quite straightforward. However, it may result in more registrations than other similar schemes. An improved MBR scheme called MBIR (MBR with implicit registration) was proposed to reduce registration cost of MBR and its approximated performance was analyzed. In this study, we point out some problems of the previous analysis method and propose an exact analysis method of MBIR. Using the exact analysis method, we show that the previous analysis includes considerable errors and improvement of MBIR in our study seems to be larger than in the previous study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.733-739
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• 2011

Recently, a lots of research proposals and results on mobile sensor network are actively announced. The most of such works are based on general-purposed network simulators such as ns-2, mathlab, etc. But, It is not easy to model and simulate the detail activities of each sensor node, data deliveries between them, and its cost such as power consumption and resource utilization, so that the simulation results of those simulators show the limited aspects of overall networks features or performance metrics. In this paper proposed, power consumption of each node, performance, mobility, and location information in operation-level of the network that can simulate a wireless sensor network simulator platform. Because the network routing algorithm analysis of being developed in an existing becomes available, the proposed simulator can usability in the new network routing algorithm development.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.831-840
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• 2010

While Wireless Internet services were activated, many users got possible to use various Internet services without limitation in location. In particular, the demands to Wireless Internet Services are getting expanded because mobile devices that support high mobility are getting smarter. However, if a user uses various wireless networks, much limitation occurs in network setting when they move to another network. This is because there are few appropriate Handover Mechanisms to support Heterogeneous Network. So, this paper propose that Fast-Handover for Vertical Network Handover with MIH in PMIPv6 to support heterogeneous network and to reduce the handover latency time. Analysis result presented in this paper shows that by carefully selecting suitable system configuration model and parameters, suggestion has reduced latency time of 26% and packet losses of 90% (Avg.) at the maximum in comparison with original PMIPv6 handover.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.886-892
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• 2010

It is possible to use wireless communication any time in every place because of well-developed wireless networks and mobile devices. The AVL(Automatic Vehicle Location) system, therefore, has made practical use in situation control, distribution industry, home delivery service, and ITS(Intelligent Transportation System) area. In this paper, we design and implement an AVL system in order to use for fire fighting activities such as emergency rescue and relief. To do this, first, we investigate and analyze the existing researches and systems related to AVL system. In details, we develop an AVL server and clients to support stable communication each other using wireless networks. Using AVL system, calling cars find the position of accidents quickly and the fire defense headquarters control unforeseen accidents efficiently because the state of calling cars are confirmed in real time by their GPS data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2919-2925
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• 2014

Because of the rapid growth of mobile communication and wireless communication, Location-based services are handled in many applications. So, the management and analysis of spatio-temporal data are a hot issue in database research. Index structure and query processing of such contents are very important for these applications. This paper addressees algorithms that make index structure by using Douglas-Peucker Algorithm and process nearest neighbor search query efficiently on moving objects trajectories. We compare and analyze our algorithms by experiments. Our algorithms make small size of index structure and process the query more efficiently.

• Journal of Internet of Things and Convergence
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• v.6 no.2
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• pp.1-10
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• 2020

The mobile application based on the Android platform is simple to decompile, making it possible to create malicious applications similar to normal ones, and can easily distribute the created malicious apps through the Android third party app store. In this case, the Android malicious application in the smartphone causes several problems such as leakage of personal information in the device, transmission of premium SMS, and leakage of location information and call records. Therefore, it is necessary to select a optimal model that provides the best performance among the machine learning techniques that have published recently, and provide a technique to automatically identify malicious Android apps. Therefore, in this paper, after adopting the feature engineering to Android apps on official test set, a total of four performance evaluation experiments were conducted to select the machine learning model that provides the optimal performance for Android malicious app detection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9B
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• pp.1314-1321
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• 2010

This system configures a position Sensor as installing on the ship and a guidance system docking of ship what distinguish of the ship about the use and size. The maintain system is received the result of distinction via UWB reader. This system send a information of ship of docking position to user. Thus it suggests the safety to prevent from crash among ships and saves energy and stop waste. The proposed system periodically updates the information of docking position of the ship and monitors in real-time according to the user's request from personal mobile devices. In this paper, we implement of a guidance system Testbed for docking of the ship using position UWB sensor. And user is provided convenience to find easily user's ship in docking area through user interface with Java. Addedly it is possible to prevent ship theft.