• Journal of Information Processing Systems
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• 제12권2호
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• pp.263-274
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• 2016

The exceptional development of electronic device technology, the miniaturization of mobile devices, and the development of telecommunication technology has made it possible to monitor human biometric data anywhere and anytime by using different types of wearable or embedded sensors. In daily life, mobile devices can collect wireless body area network (WBAN) data, and the co-collected location data is also important for disease analysis. In order to efficiently analyze WBAN data, including location information and support medical analysis services, we propose a geohash-based spatial index method for a location-aware WBAN data monitoring system on the NoSQL database system, which uses an R-tree-based global tree to organize the real-time location data of a patient and a B-tree-based local tree to manage historical data. This type of spatial index method is a support cloud-based location-aware WBAN data monitoring system. In order to evaluate the proposed method, we built a system that can support a JavaScript Object Notation (JSON) and Binary JSON (BSON) document data on mobile gateway devices. The proposed spatial index method can efficiently process location-based queries for medical signal monitoring. In order to evaluate our index method, we simulated a small system on MongoDB with our proposed index method, which is a document-based NoSQL database system, and evaluated its performance.

• Asia pacific journal of information systems
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• 제14권3호
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• pp.121-144
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• 2004

Developing a personalized system on a user's behalf which is working around the Internet-based marketplace is one of the challenging issues in intelligent e-business, especially mobile commenrce. It has been highly recommended that such a mobile personalized system has to perceive the user's needs a priori by tracking user's current context such as location with activity and then to identify the current needs dynamically and proactively. Automatically and unobtrusively getting user's context is an inevitable feature for the development of autonomous mobile commenrce. However, personalization methodologies and their feasible architectures for context-aware mobile commerce have been so far very rare. Hence, this paper aims to propose a context-aware mobile commerce development methodology by applying agent and semantic web technologies for personalized reminder system, which is one of the mobile commerce support system. We revisited associationism to understand a buyer's need identification process and adopt the process as 'purchase based on association' to implement a personalized reminder system. Based on this approach, we have showed how the agent-based semantic web service system can be used to realize need-aware reminder system. NAMA(Need-Aware Multi-Agent), a prototype system, has been implemented to show the feasibility of the methodology and framework under mobile setting proposed in this paper. NAMA embeds bluetooth-based location tracking module and identify what a user is currently looking at through her/his mobile device such as PDA. Based on these capabilities, NAMA considers the context, user profile with preferences, and information about currently available services, to aware user's current needs and then link her/him to a set of services, which are implemented as web services.

• Journal of Communications and Networks
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• 제7권2호
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• pp.207-221
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• 2005

The proliferation of wireless local area networks (WLANs) offering high data rate in hot spot area have spurred the demand for possible WLANs and third-generation (3G) cellular network integration solutions as the initiative step towards 4G systems. This paper provides a novel architecture for seamless location-aware integration of WLANs into 3G cellular networks and also an analysis for the efficient handover techniques. We introduce location as a key context in secure roaming mechanism for context-aware interworking in 4G systems. The fast secure roaming with location-aware authentication is implemented at an entity called location-aware service (LAS) broker that utilizes the concepts of direction of user and pre-warming zone. The location-ware interworking architecture supports seamless roaming services among heterogeneous wireless networks including WLANs, wireless metropolitan area networks (WMANs), and 3G cellular networks. This paper also includes a description of procedures needed to implement efficient mobility and location management. We show how the LAS broker with pre-warming and context transfer can obtain significant lower latency in the vertical handover.

• 정보처리학회논문지C
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• 제8C권6호
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• pp.831-838
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• 2001

이동정보서비스는 휴대단말을 소지한 사용자가 생활현장에서 정보를 처리할 때 유용성을 제공코자 하는 서비스 패러다임을 말한다. 여기서 사용자의 이동성, 현장성으로 인하여 정보를 요구하고 있는 현재 상황(context)에 적응적인 서비스 방법론은 매우 중요한 기술요소로 인식되고 있다. 본 논문은 이동정보서비스에서 고려될 수 있는 상황 중에서 사용자의 위치 변화에 따른 상황인식요소인 위치인식 이동정보서비스를 위한 프리패칭 방법론을 다룬다. 먼저 단말 혹은 사용자의 이동 패턴을 상황인식에 활용하기 위하여 속도기반 이동모델을 채택한다. 이동속도 및 이동방향을 근거로 하여 프리패칭의 대상정보를 선정하는 프리패칭 영역을 정의함으로써, 프리패칭되는 대상 정보의 수를 효과적으로 제한하는 반면에 현재 상황에 최적인 정보서비스를 적응적으로 처리하는 기반을 제공한다. 제안된 프리패칭 방법론은 시뮬레이터를 이용하여 효용성 관점에서 분석 평가하였다. 본 논문에서 제안된 방법론은 다른 이동정보서비스 상황인 서비스 요구시간, 단말 입출력장치, 네트워크 전송률 등의 활용에 개념적으로 확장될 수 있을 것으로 기대된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권1호
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• pp.135-158
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• 2018

High-Speed vehicles can be considered as multiple mobile nodes that move together in a large-scale mobile network. High-speed makes the time allowed for a mobile node to complete a handover procedure shorter and more frequently. Hence, several protocols are used to manage the mobility of mobile nodes such as Network Mobility (NEMO). However, there are still some problems such as high handover latency and packet loss. So efficient handover management is needed to meet Quality of Service (QoS) requirements for real-time applications. This paper utilizes the cross-layer seamless handover technique for network mobility presented in cellular networks. It extends this technique to propose QoS-aware NEMO protocol which considers QoS requirements for real-time applications. A novel analytical framework is developed to compare the performance of the proposed protocol with basic NEMO using cost functions for realistic city mobility model. The numerical results show that QoS-aware NEMO protocol improves the performance in terms of handover latency, packet delivery cost, location update cost, and total cost.

• 로봇학회논문지
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• 제7권2호
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• pp.150-159
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• 2012

In this paper, we propose a cost-aware Rapidly-exploring Random Tree (RRT) path planning algorithm for mobile robots. A mobile robot is presented with a cost map of the field of interest and assigned to move from one location to another. As a robot moves, the robot is penalized by the cost at its current location according to the cost map. The overall cost of the robot is determined by the trajectory of the robot. The goal of the proposed cost-aware RRT algorithm is to find a trajectory with the minimal cost. The cost map of the field can represent environmental parameters, such as temperature, humidity, chemical concentration, wireless signal strength, and stealthiness. For example, if the cost map represents packet drop rates at different locations, the minimum cost path between two locations is the path with the best possible communication, which is desirable when a robot operates under the environment with weak wireless signals. The proposed cost-aware RRT algorithm extends the basic RRT algorithm by considering the cost map when extending a motion segment. We show that the proposed algorithm gives an outstanding performance compared to the basic RRT method. We also demonstrate that the use of rejection sampling can give better results through extensive simulation.

• 정보처리학회논문지A
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• 제12A권4호
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• pp.273-280
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• 2005

유비쿼터스 환경에서 사용자 혹은 장비들의 위치 이동은 QoS와 밀접한 관계를 가진다. 그러므로 이동 객체의 위치를 정확히 감지하고, 높은 품질의 서비스를 제공할 수 있도록 돕는 위치 감지 시스템은 매우 중요한 역할을 한다. 하지만, 위치 감지 시스템은 적용되는 감지 범위에 따라 프로세스 전략이 다르고 사용이 제한적이기 때문에 사용자에게 신뢰성있는 QoS를 보장하기 힘든 실정이다. 본 연구에서는 지능적인 모니터링 기법을 사용하여 시스템 상황을 분석하고 자동으로 최적의 감지 프로세스 전략을 선택하는 자동화 구조를 설계하였고, 시뮬레이션을 통해 제안한 자동화 구조의 성능을 평가하였다. 실험을 통해 자가 최적화 기법을 이용한 본 구조는 동적인 네트워크 상황에서도 사용자에게 변함 없이 높은 QoS를 보장하는 것을 확인하였다.

• Journal of Information Technology Applications and Management
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• 제12권3호
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• pp.97-109
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• 2005

The internet and wireless communication technologies are creating ubiquitous environments in which various services are expected anytime and anywhere. Many hardware facilities have been developed and system structures are suggested for mobile services to realize a ubiquitous computing environment with appropriate quality. But these applications are not designed in the consideration of the general capabilities to perform user's wireless and mobile communication/transaction. Consequently, different needs from users are not sufficiently satisfied yet. In this study, we suggest structure of the emerging network system for mobile commerce that provides users with seamless and ubiquitous environments using location information which exploit context-aware technology.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권6호
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• pp.1152-1168
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• 2010

Recently, due to the prevalence of various mobile devices and wireless broadband networks, there has been a significant increase in interest and demand for multimedia streaming services such as the mobile IPTV. In such a wireless broadband network, transmitting a continuous stream of multimedia data is difficult to achieve due to mobile stations (MSs) movement. Providing Quality of Service (QoS) for multimedia video streaming applications requires the server and/or client to be network-aware and adaptive. Therefore, in order to deploy a mobile IPTV service in wireless broadband networks, offering users efficient wireless resource utilization and seamlessly offering user perceived QoS are important issues. In this paper, we propose a new adaptive streaming scheme, called MARC (Mobile-aware Adaptive Rate Control), which adjusts the quality of bit-stream and transmission rate of video streaming based on the wireless channel status and network status. The proposed scheme can control the rate of multimedia streaming to be suitable for the wireless channel status by using awareness information of the wireless channel quality and the mobile station location. The proposed scheme can provide a seamless multimedia playback service in wireless broadband networks in addition to improving the QoS of multimedia streaming services. The proposed MARC scheme alleviates the discontinuity of multimedia playback and allocates a suitable client buffer to the wireless broadband network. The simulation results demonstrate the effectiveness of our proposed scheme.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.138-143
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• 2002

This paper describes a framework for extending GIS databases to support moving object data type and query language. The rapid progress of wireless communications, positioning systems, and mobile computing devices have led location-aware applications to be essential components for commercial and industrial systems. Location-aware applications require GIS databases system to represent moving objects and to support querying on the motion properties of objects. For example, fleet management applications may require storage of information about moving vehicles. Also, advanced CRM(Customer Relationship Management) applications may require to store and query the trajectories of mobile phone users. In this trend, maintaining consistent information about the location of continuously moving objects and processing motion-specific queries is challenging problem. We formally define a data model and query language for mobile objects that includes complex evolving spatial structure, and propose core algebra to process the moving object query language. Main profit of proposed moving objects query language and algebra is that proposed model can be constructed on the top of GIS databases.