• Journal of Korea Multimedia Society
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• v.21 no.5
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• pp.583-591
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• 2018

With the development of ICT(Information and Communication Technology), the number of smart devices is rapidly increasing. LBS(Location Based Service) applications that provide user's location based service are used in various fields. There is also a growing demand for indoor precision positioning technology to provide seamless services. In this paper, we propose an indoor positioning system that estimates the location of a smartphone user. The proposed algorithm determines whether the received signal is LOS(Line-of-Sight) or NLOS(Non-Line of-Sight) in order to decrease multipath effect by the indoor environment. The proposed positioning algorithm is very simple and requires only the AP(Access Point) coordinates. In addition, it requires only two APs for estimating the location of a smartphone user. The proposed algorithm is a practically applicable technology without any additional hardware and kernel modification in the smartphone. In the experiment results, the reliability of the positioning system was found to be within 0.83 m.

• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.91-97
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• 2014

In this paper, we propose weighted detection probability with distance between primary user and secondary users by using cooperative spectrum sensing based on energy detection. And we analysis and simulate the result. We suggest different distance between primary user and secondary users and the wireless channel between primary user and secondary users is modeled as Gaussian channel. From the simulation results of the cooperative spectrum sensing with weighted method make coverage bigger compared with non-weight, and We show higher sensing efficiency when we put weight detection probability than before method.

• The Journal of Korean Physical Therapy
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• v.30 no.4
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• pp.151-157
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• 2018

Purpose: This study was conducted to identify the characteristics of physical therapy service utilization and user satisfaction depending on the experience with therapeutic exercise or ultrasound intervention among elderly persons using senior centers. Methods: The subjects were adults aged over 60 years (total 215) recruited in 40 senior centers located in each province in South Korea. Subjects responded to questions concerning overall demographics factors, utilized characteristics of physical therapy service and 12 variety user satisfactions with effectiveness, facilities, and therapist using a survey instrument. The collected data were analyzed by Fishers' exact tests and t-tests using the SPSS 21.0 program to compare the results of elderly persons who had or had not experienced exercise therapy or ultrasound therapy. Results: The participants that experienced ultrasound therapy or therapeutic exercise reported significantly higher overall results pertaining to effectiveness of physical therapy and a clear explanation from physical therapist's satisfaction than those who were non-experienced. Satisfaction with pain relief was significantly higher among elderly who experienced therapeutic exercise than those who did not. Those who underwent ultrasound therapy showed significantly higher satisfaction with facilities and location than those who did not. Conclusion: The results of this study suggest that satisfaction among users differs by type of physical therapy. In the future, physiotherapy services provided in senior centers needs to be designed to improve the effectiveness of physical therapy, professionalism of physical therapists and comfort of facility.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.455-458
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• 2003

The variety of document ranking algorithms have developed to provide efficient mining results for user's query on the web environment. The typical ranking algorithms are the Vector-Space Model based on the text, PsgeRank and HITS algorithms based on the hyperlink structures and other several improvement algorithms. All these are for the user's convenience and preference. However, these algorithms are usually developed on then Horizontal and non-hierarchial web environments and are not suitable for the hierarchial web environments such as enterprise and defense networks. Thus, we must consider the special environment factors in order to improve the ranking algorithms. In this paper, we analyze the several typical algorithms used by hyperlink structures on the web environment. We, then suggest a configuration of the hierarchical web environment and also give the relations between agents of the web mining system. Next, we propose an improved ranking algorithm suitable to this kind of special environments. The proposed algorithm is considered both the hyperlink structures of the documents and the location of the user of the hierarchical web.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.677-687
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• 2016

Multi-way relay networks (MWRNs) allow multiple users to exchange information with each other through a single relay terminal. MWRNs are often incorporated with capacity achieving lattice codes to enable the benefits of high-rate signal constellations to be extracted. In this paper, we analytically characterize the symbol error rate (SER) performance of a functional decode and forward (FDF) MWRN in the presence of channel estimation errors. Considering M-ary quadrature amplitude modulation (QAM) with square constellations as an important special case of lattice codes, we obtain asymptotic expressions for the average SER for a user in FDF MWRN. The accuracy of the analysis at high signal-to-noise ratio is validated by comparison with the simulation results. The analysis shows that when a user decodes other users with better channel conditions than itself, the decoding user experiences better error performance. The analytical results allow system designers to accurately assess the non-trivial impact of channel estimation errors and the users' channel conditions on the SER performance of a FDF MWRN with M-QAM modulation.

• Journal of Korean Society for Quality Management
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• v.30 no.3
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• pp.20-37
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• 2002

In this paper, we studied the purpose of this paper is like that; the first one is to find the factors associated with operational strategy by variable website types classified into information-providing type, product-providing type and service- providing type by user approach purposes. The second one is to propose the successful operational strategy through analyzing the factors affecting the financial and non-financial performance of websites. A framework of research model including above factors is developed and tested statistically. The data are collected from Internet website experts of 80 Korean firms through survey. The main results of this research are as follows. First, in information-providing websites, the community factor is regarded as the most important factor But for the Improvement of the performance, not only community factor but also user interface, customization, total quality and playfulness factors should be regarded as important factors equally. Second, in product-providing websites, customization, total quality and visual design factors are regarded as important factors. But for the improvement of the performance, community and visual design factors should be regarded as important factors. Third, in service-providing websites, user interface, customization and community factors should be regarded as important factors in order to improve the performance.

• Journal of KIISE:Software and Applications
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• v.36 no.2
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• pp.144-152
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• 2009

To provide intelligent service in mobile environment, it needs to estimate user's intention or requirement, through analyzing context information of end-users such as preference or behavior patterns. In this paper, we infer context information from uncertain log stored in mobile device. And we propose the inference method of end-user's behavior to match context information with service, and the proposed method is based on context-tree. We adopt bayesian probabilistic method to infer uncertain context information effectively, and the context-tree is constructed to utilize non-numerical context which is hard to handled with mathematical method. And we verify utility of proposed method by appling the method to intelligent phone book service.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.362-367
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• 2005

Control network adopted in the national power-plant or manufactory are mostly vendor-dependent products, which have their own special specification, components and individual communication methods. These systems not only raise installation cost, but also bring many difficulties to maintenance and extension. To overcome these problems, this paper introduces a development and application case of a new "PC/Ethernet-based fieldbus" architecture and protocol to be used in mid-level fieldbus. The designed system has a basic idea of "3 Layers fieldbus over Standard-LAN" and implemented on PCs. PC gives user friendly environment. By using an open standard Ethernet in layer 1,2, the system has low cost, wide communication bandwidth and high compatibility. Layer 3 protocol designed for large realtime data communication makes user bypass TCP/IP layer and gives user direct access to the Ethernet. This new protocol eliminates potential collision of Ethernet, and transmits large periodic/non-periodic control data by using long-frame/wide-bandwidth of Ethernet effectively, and offers simple API-Services to the upper layer. Since the system have installed in H-power plant simulator and U-nuclear power plant simulator in Korea, it have been proved to be efficient and stable without any trouble in realtime communication service for full-scope plant simulator that has a lot of control elements.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.317-321
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• 2006

게임의 재미요소를 증대 시키고, 게임 생명주기(Life-Cycle)를 늘어나게 하기 위해 다양한 방법이 연구 중이다. 현실감 있는 그래픽 효과와 뛰어난 음향 효과 등과 함께 게임 플레이어의 게임 스타일이 반영된 게임을 만들기 위한 방법이 대표적이 예라 할 수 있다. 그 중 게임 플레이어의 스타일을 게임에 다시 이용하기 위해서는 플레이어의 인지과정이 요구되며, 인지된 결과를 이용하여 플레이어를 모델링(User Modeling)한다. 하지만, 게임의 종류와 특성에 따라 다양한 게임이 존재하기 때문에 플레이어를 모델링하기 어렵다는 문제를 가지고 있다. 본 논문에서는 게임에서 정의된 FSM(Finite State machine)을 이용하여 플레이어가 선택한 행동 패턴을 분석하고 적용하는 방법과 다양한 게임에서 이용 할 수 있는 스크립트 형태의 NPC 행동 패턴 변경 방법을 제안한다. 플레이어의 데이터를 분석하여 얻은 결과는 FSM을 변경하여 새로운 행동을 보이는 NPC(Non-Player Characters)를 생성하는데 사용되며, 이 캐릭터는 게임의 특성과 플레이어의 최신 행동 패턴 경향을 학습한 적용형 NPC라 할 수 있다. 실험을 통하여 사용자의 행동과 유사한 패턴을 보이는 NPC의 생성을 확인할 수 있었으며, 게임에서 상대적인 또는 적대적인 캐릭터로 유용하게 사용 될 수 있다.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.7
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• pp.659-665
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• 2001

Relevance feedback is the most popular query reformulation strategy in a relevance feedback cycle, the user is presented with a list of the retrieved documents and, after examining them, marks those which are relevant. In practice, only the top 10(or 20) ranked documents need to be examined. The main idea consists of selecting important terms, or expressions, attached to the documents that have been identified as relevant by the user, and of enhancing the importance of these terms in a new query formulation. The expected effect is that the new query will be moved towards the relevant documents and away from the non-relevant ones. Local analysis techniques are interesting because they take advantage of the local context provided with the query. In this regard, they seem more appropriate than global analysis techniques. In a local strategy, the documents retrieved for a given query q are examined at query time to determine terms for query expansion. This is similar to a relevance feedback cycle but might be done without assistance from the user.