• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.285-290
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• 2007

본 논문에서 구현하고자 하는 유비쿼터스 컴퓨팅 응용에 필요한 위치 인식 시스템의 주 요소는 블루투스 프로토콜 스택(BlueZ)에서 제공하는 RSSI(Received Signal Strength Indicator) 값을 측정하는 블루투스 AP, 측정된 RSSI 값을 위치 인식 서버에 전달하기 위한 무선 AP 공유기 그리고, 받은 데이터로 위치 값을 측정하는 위치 인식 서버 및 Context Broker(고 수준의 상황 정보를 추론하는 서버 역할)로 이루어져있다. 전체적인 동작 시스템은 위치 값을 측정하고자 하는 이동 매제(마스터)를 중심으로 최대 여덟 개까지 네트워크가 가능한 블루투스 AP(슬레이브)장치로 구성된 피코넷(Piconet) 영역에서 삼각측량 필요에 적절한 세 개의 블루투스 AP를 RSSI값을 이용하여 분류 한 후 이동 매체의 위치를 측정한다. 그 결과로 나온 데이터는 피코넷 영역에서 가장 가까운 무선 AP 공유기를 거쳐서 위치 값을 측정하는 위치 인식 서버에 전달한 후, 그 결과 값으로 Context Broker에서 상황 정보를 추론해서 Community Manager에서 유비쿼터스 컴퓨팅 응용에 맞게 서비스를 구현한다. 또한, 위와 같은 시스템 내부 구조 된 데이터처리는 리눅스 운영체제 내에서 디바이스 드라이버와 사용자 프로그램으로 구현된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1120-1127
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• 2008

This paper presents implementation of localization system using UWB (Ultra-Wide Band) sensors and its experimental results along with development of context-aware services. In order for precise measurement of position, we experimented various conditions of pitch angles, yaw angles, number of sensors, height of tags along with measuring errors at each installation. As an application examples of the location tracking system, we developed an intelligent health training management system based on context-aware technology. The system provides appropriate training schedule to a trainee by recognizing position of the trainee and current status of gymnastic equipments and note the usage of the equipment through a personal digital assistant (PDA). Error compensation on position data and moving direction of the trainee was necessary for context-aware service. Hence, we proposed an error compensation algorithm using velocity of the trainee. Experimental results showed that proposed algorithm had made error data reduce by 30% comparing with the data without applying the algorithm.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.7
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• pp.738-742
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• 2008

The user model is an indispensable factor for providing users with personalized. services in the ubiquitous computing environment. In general user models, services which users prefer should be described in advance so that the system can recognize and interpret them automatically. Also, user's preferences as to the change of situation are not reflected in general user models due to their ignoring the situation. In this paper, we propose the self-growing user model which learns user experience and the system which automatically provides personalized community services through extracting user preferring services by situation.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.55-60
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• 2005

Ubiquitous computing environment means the computing environment that has taken its position so closely with the ordinary living so much like air or water. In building up the U-Korea, one of the important issues is the social issue from the drastic increase of senior population. The contemporary society has its distinct trend in increase of senior household following the nuclear family orientation, increase of working parents with the advancement of women in society, unable to support seniors for long distance or short distance of business trip and other reasons that the need of senior welfare has been ever more felt. Accordingly, the Ministry of Government Affairs and Home Administration has developed the wireless paging system to make prompt response system for 119 Rescue when the single senior is encountered with emergency situation that is has been widely provided for the socially neglected people such as single senior, the disabled persons and others. Currently, the wireless paging system is operated as the sub-system for emergency rescue information system, but due to the lack of reliability of product, problems of terminal portable transmitter, receptor and others, rejection of beneficiary and lack of knowledge in use, insufficient management and supervision of managing officers, the efficiency has been declined that there is a need of development for the system. Therefore, this study proposes the context aware information structure of the subject of ubiquitous wireless paging system required for the development of the wireless paging system model of ubiquitous environment that improved the problems of currently operated wireless paging system.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.542-546
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• 2007

In the vision of ubiquitous computing environment, smart objects would communicate each other and provide many kinds of information about user and their surroundings in the home. This information enables smart objects to recognize context and to provide active and convenient services to the customers. However in most cases, context-aware services are available only with expert systems. In this paper, we present generalized activity recognition application in the smart home based on a naive Bayesian network(BN) and fuzzy clustering. We quantize continuous sensor data with fuzzy c-means clustering to simplify and reduce BN's conditional probability table size. And we apply mutual information to learn the BN structure efficiently. We show that this system can recognize user activities about 80% accuracy in the web based virtual smart home.

• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.1-16
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• 2011

The real-time ubiquitous environment is required to be able to process a series of sensor data within limited time. The whole sensor data processing consists of several phases : getting data out of sensor, acquiring context and responding to users. The ubiquitous computing middleware is aware of the context using the input sensor data and a series of data from database or knowledge-base, makes a decision suitable for the context and shows a response according to the decision. When the real-time ubiquitous environment gets a set of sensor data as its input, it needs to be able to estimate the delay-time of the sensor data considering the available resource and the priority of it for scheduling a series of sensor data. Also the sensor data of higher priority can stop the processing of proceeding sensor data. The research field for such a decision making is not yet vibrant. In this paper, we propose a queuing time computation algorithm for sensor data processing in real-time ubiquitous environment.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.286-291
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• 2008

Intelligence of collaborative environments starts from a trial to provide optimal services to with users based on real-time information about participants and environments of the collaboration itself. Up to now, we can collect information such as temperature, light, time, each participant's gestures, faces, voices, and locations by adopting ubiquitous computing technologies. However, since social relationship is intrinsic to collaborative activities, the relationships and roles among participants should be fully considered to provide optimal services. To do so, we have to integrate collected data from various sensors and extracted data about relationships and roles among participants as unified one context. Thus, this paper designs collaborative services filtered, by using the integrated data as a context, and introduces an implemented example, context-aware based interactive display service, called as smart meeting system (SMeet system).

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.486-494
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• 2014

Intelligent homes consist of ubiquitous sensors, home networks, and a context-aware computing system. These homes are expected to offer many services such as intelligent air-conditioning, lighting control, health monitoring, and home security. In order to realize these services, many researchers have worked on various research topics including smart sensors with low power consumption, home network protocols, resident and location detection, context-awareness, and scenario and service control. This paper presents the real-time metabolic rate estimation method that is based on measured heart rate for human adaptive appliance (air-conditioner, lighting etc.). This estimation results can provide valuable information to control smart appliances so that they can adjust themselves according to the status of residents. The heart rate based method has been experimentally compared with the location-based method on a test bed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.734-741
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• 2008

The modern people effort to lead good life. Specially, the patients which prevention of a disease only is cure from this diabetes patient, the old and weak, the hospitals needing a treatment through exercises, and receive medical treatment in houses cure exercise according to exercise prescription. These papers developed a Ubiquitous Care Management system based on Zigbee. This is a system supporting so as accumulation manages the exercise history information that occurred when get exercises prescription, and exercise systematically, and to do preventive of a disease. Can confirm own exercise history and health information through web pages, and this system notifies contents about an exercise treatment to patients as use a cellular phone.

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.73-83
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• 2008

This paper proposes an implementation of an orchestration service of web services, which work as context aware applications in Ubiquitous Computing. The proposed method alms to decrease the cost of adapting to the context changes. UC requires the context adaptation more than any other computing environments, and it works based on networks of various heterogeneous platforms. Web services on SOA could be one of the solutions for the requirements. This paper proposes the way how to implement an orchestration service of SOA to handle the context adaptation while keeping the performance high. We develops an implementation model of orchestration services of web services, and the model decreases the number of code lines of the orchestration service. This paper also shows a simple empirical study, and it also analyzes two different method implementing the polymorphism, overloading and overriding.