• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2005년도 춘계학술대회
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• pp.131-138
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• 2005

Recommender systems have been widely advocated as a way of coping with the problem of information overload in e-business environment. Most of the existing recommender systems focused on what kind of items to recommend, although when to recommend to the target customer considering their context is an important issue. Even right item might be a spam advertisement or wrong recommendation for the customer if it can not be recommended at the right context. It is particularly important for recommendations where the user's context is changing rapidly, such as in both handheld and ubiquitous computing environment. Therefore, we propose CARS (Context-Aware Recommender System) based on CBR and context-awareness for ubiquitous computing environment. CBR is used to generate a target customer class and proper context. Context-awareness is used to gather suer context information from sensors, networks, device status, user profiles, and other sources. An illustrative case example is suggested to explain the procedure of CARS.

• 한국안전학회지
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• 제23권5호
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• pp.35-42
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• 2008

There are many efforts toward the development of next generation gas safety management systems to improve the assurance, availability, and efficiency of the extant systems. Among them, the application of ubiquitous technology, such as RFID and USN, to the system is regarded as a promising approach for enabling such an innovation. Recently the ubiquitous technology became much affordable and available than before thanks to the reduced production cost and wide proliferation of the ubiquitous devices. In this paper, we analyze the core requirements for the next generation gas safety management systems based on the ubiquitous technology, and present an architectural design of a middleware to facilitate the realization of the system. We formally define an event model and present how to specify various situations related to gas safety management using the proposed event model.

• 한국멀티미디어학회논문지
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• 제7권6호
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• pp.767-780
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• 2004

Interaction requires dynamic relationship between objects. In ubiquitous computing environment, interaction between human and the environment is implied. Tactile interaction has so far been less addressed, while tactile sensation should be an important topic in the field of multimedia study. This paper describes development of a novel PVDF (Polyvinylidene Fluoride) dynamic tactile sensor and associated experiments. PVDF dynamic tactile sensors detect touch events applied to the sensor skin by low frequency components of the signal. Rubber skin-covered sensing material was mounted on the bones. Robust performance with low noise was figured out in our robotic experiment. Whereas most conventional sensors are interested in measurement, our dynamic tactile sensor is sensitive to change of state, which could be a key for economic understanding of happenings in the dynamic world. We note that dynamic sensing uses motion as a part of sensing modality We suggest that dynamic sensing be understood in technological terms in the perspective of interactive media and ubiquitous computing.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.274-277
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• 2008

Rekeying is the process of changing the encryption key of an ongoing communication. The main objective is to limit the amount of data encrypted with the same key. The IEEE 802.11 standard defines the Wired Equivalent Privacy, or WEP, encapsulation of 802.11 data frames. MAC at sender encrypts the payload (frame body and CRC) of each 802.11 frame before transmission using RC4 stream cipher. MAC at receiver decrypts and passes data to higher level protocol. WEP uses symmetric key stream cipher (RC4) where same key will be used for data encryption and decryption at the sender and the receiver. WEP is not promising with the advancement of the wireless technology existing today. We propose to use the existing information to define the security attributes. This will eliminate the steps that regenerated keys have to be sent to each other over certain period. The rekeying scheme is according to the number of bytes transmitted. Therefore, even the attacker has recorded the packets, it will be insufficient information and time for the attacker to launch the attacks as the key is not deterministic. We develop a packet simulation software for packet transmission and simulate our propose scheme. From the simulation, our propose scheme will overcome the weak WEP key attack and provide an alternative solution to wireless packet transmission. Besides that, our solution appears to be a software approach where only driver updates are needed for the wireless client and server.

• 전자공학회논문지CI
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• 제46권2호
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• pp.27-35
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• 2009

고령화 사회로의 진입과 삶의 질 향상에 따라 의료산업의 패러다임이 u-헬스케어(Healthcare)로 빠르게 변화하고 있다. u-헬스케어로의 변화는, 질병의 진단과 치료와 같은 의료서비스의 사후(事後)처리적인 관점에서 예방과 관리라는 사전(事前)예방적인 관점으로의 변화라는 점에서 의미가 있다. 그러나 u-헬스케어에 대한 관심은 새로운 서비스 도출과 측정기기(센서류)의 개발, 의료정보 표준화와 통합에만 그 관심이 집중되고 있다. 따라서 본고에서는 유비쿼터스 지능공간을 구성하고 사용자에게 u-헬스케어 기술을 제공함에 있어 "사용자 중심의 u-헬스케어 기술"이라는 개념을 적용함으로써, u-헬스케어 기술을 유비쿼터스 구성의 기본철학인 사라지는 컴퓨팅(Disappear Computing), 보이지 않는 컴퓨팅(Invisible Computing), 조용한 컴퓨팅(Calm Computing)과 사용자 중심(User Centered)의 기술 개발을 통해 실현 가능하도록 하는 방법에 대하여 소개하고자 한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.257-260
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• 2008

We build middleware architecture with J2EE and LiveGraph to process different ubiquitous healthcare application's data and process that data into useful information, which can play a most important role in decision making in ubiquitous Healthcare System. Application developers mostly rely on third party middleware, tools and libraries (i.e., webservers, distributed middleware such as CORBA, etc.) to respond the emerging trends of their target domain. With this middleware we tried to enhance the efficiency of application by decrease their memory uses, data processing and decision making on another web module which is independent of each application. For middleware system, we proposed an algorithm by which we can find some important conclusion about different health status likewise ECG, Accelerometer. etc., which can be used in various data processing and determine the current health status. In this paper we also analyze some different low level and high level middleware technology which were used to build different kind middleware likewise CAMUS, MiLAN and try to find the best solution in the form of middleware for Ubiquitous Healthcare Information System.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2008년도 한국컴퓨터종합학술대회논문집 Vol.35 No.1 (A)
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• pp.231-232
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• 2008

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 한국컴퓨터종합학술대회논문집 Vol.34 No.1 (A)
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• pp.155-156
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• 2007

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 한국컴퓨터종합학술대회논문집 Vol.34 No.1 (A)
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• pp.252-253
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• 2007

• 한국산학기술학회논문지
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• 제7권3호
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• pp.365-372
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• 2006

본 논문에서는 차세대 교육을 Ubiquitous Learning (u-Learning)으로 전망하며, 서울 소재 C초등학교와 H초등학교의 학교 홈페이지를 활용하여 u-Learning의 운영 사례를 비교 연구하고, u-Learning의 학습효과 및 학습자의 만족도를 연구하였다. 또한 차세대 u-Learning 시스템 구조를 제안한다.