• Journal of Information Processing Systems
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• v.12 no.4
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• pp.577-590
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• 2016

We studied the current state-of-the-art of Smart TV, the challenges and the drawbacks. Mainly we discussed the lack of end-to-end solution. We then illustrated the differences between Smart TV and IPTV from network service provider point of view. Unlike IPTV, viewer of Smart TV's over-the-top (OTT) services could be global, such as foreign nationals in a country or viewers having special viewing preferences. Those viewers are sparsely distributed. The existing TV service deployment models over Internet are not suitable for such viewers as they are based on content popularity, hence we propose a community based service deployment methodology with proactive content caching on rendezvous points (RPs). In our proposal, RPs are intermediate nodes responsible for caching routing and decision making. The viewer's community formation is based on geographical locations and similarity of their interests. The idea of using context information to do proactive caching is itself not new, but we combined this with "in network caching" mechanism of content centric network (CCN) architecture. We gauge the performance improvement achieved by a community model. The result shows that when the total numbers of requests are same; our model can have significantly better performance, especially for sparsely distributed communities.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.1
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• pp.104-115
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• 2010

Development of the system which provides services using diverse sensors is expanding due to the widespread use of ubiquitous technology, and the research on the security technologies gaining attention to solve the vulnerability of ubiquitous environment's security. However, there are many instances in which flexible security services should be considered instead of strong only security function depending on the context. This paper used Fuzzy algorithm and MAUT to be aware of the diverse contexts and to propose context-aware security service which provides flexible security function according to the context.

• Journal of KIISE:Software and Applications
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• v.31 no.2
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• pp.111-125
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• 2004

In this paper, we applied user-centered context to Smart Home Applications. Current research activities on smart home have just focused on the infrastructure without considering user's contexts and implementation cost. We first realized the user-centered personalized services using ubi-UCAM (a Unified Context-aware Application Model), which exploited contexts from various kinds of smart sensors. We, then, verified its usefulness in the ubiquitous computing-enabled home environment. It can be extended to various application areas since it guarantees independence between sensors and services. Accordingly, it will play a key role in future smart home environment.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.801-808
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• 2009

According to development of internet and an increase in demand of multimedia contents, the contents industry is being developed. However, they are served same contents in the limited environment(user device environment, network environment) of the present contents industry. And users have difficulties in searching and finding contents since they are served contents they want and contents suitable to diverse context and affection. Therefore, it is necessary to make a system offering contents according to context and affection of users. The study proposes the system to offer contents suitable to context and affection of users whenever and wherever through diverse devices in a ubiquitous environment and designs/implementation a user device framework system that users can be offered contents suitable to their devices.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.6
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• pp.281-288
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• 2017

In Smart-cities, various types of integrated services must be linked to provide services to applications. Therefore, flexibility must be ensured between services so that various services can be efficiently provided. In order to secure the flexibility among services, it is very important to have a function to dynamically discover and invoke a desired service by searching for a semantic service by reflecting a recognized context through real-time context-aware in smart-cities. To date, quite a number of semantic service discovery techniques have been developed. However, they have not been verified as suitable for use in the smart-city domain. In this study, we tried to verify the existing ones to use a suitable one. We tested most of existing semantic service discovery techniques, but we found that none of them is suitable to our research. Therefore, we developed our own semantic service discovery technique. This paper introduces our work and presents the performance evaluation results that demonstrate that our developed works well and show good performance. For the performance evaluation, the experimental system was actually constructed and the real performance was measured. In the experiment, we implemented the semantic service discovery scenario that dynamically searches and calls the services needed to provide fire accident management services in smart cities.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.111-120
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• 2009

In this paper, we propose ubiWarehouse system which can efficiently manages mass and many kinds of parts such as automotive parts. First, user's work situation is defined systematically as context type of 5W1H, context-aware system is separated on function, and each module operates independently. An efficient route is selected and relevant parts frequently treated at the same time are gathered by calculating the suitability of parts and racks. If other users currently are on a visit or are supposed to visit soon, the hun of visit is changed making a concession for preventing collision. As a result, the proposed system with avoiding competition can provide users with routes for inbound or outbound parts, and can effectively use spaces of a warehouse by arranging racks to gather relevant parts to near location. Also, individual service can be offered by evaluating user propensity using history of the warehouse job, and the accuracy of stock information can be improved by processing of unexpected context and real-time renewing of warehousing and delivering.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1256-1264
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• 2009

When unapproved users access to healthcare system and use medical information for other malicious purposes, it could severely threaten important information related to patients' life, because in ubiquitous environment healthcare service makes patient's various examination results, medical records or most information of a patient into data. Therefore, to solve these problems, we design RBAC(Role Based Access Control) for U-healthcare that can access control with location, time and context-awareness information like status information of user and protect patient's privacy. With implementation of the proposed model, we verify effectiveness of the access control model for healthcare in ubiquitous environment.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06a
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• pp.39-40
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• 2007

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.3 no.1
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• pp.25-33
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• 2004

Open Services Gateway Initiative(OSGi)는 WAN에서 로컬 네트워크와 장치에 다양한 서비스를 적용하는 것이 가능하도록 하는 기본 구조를 만들고자 많은 기업들이 참여하여 활동하는 컨소시엄이다. 본 고에서는 OSGi에서 제시하는 시스템 구조를 살펴보고 이를 유비쿼터스 컴퓨터에 접목하기 위해 고려되는 사항과 다양한 환경에서 적용되기 위한 시스템 구조에 대하여 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.253-254
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• 2012

상황 인식 시스템에서, 핵심 요소 중의 하나가 서비스 명세이다. 지금까지 서비스 명세를 표현하기 위해서 생성 규칙, 마크업 기반 언어 및 온톨로지 기반 언어 등이 사용되었다. 이들과는 다르게, 본 논문에서는 병행 시스템 및 반응형 시스템의 속성 명세에 널리 사용되는 시제 논리를 이용하여 상황 인식 서비스를 명세하고자 한다.