• 전기학회논문지
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• 제66권8호
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• pp.1257-1264
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• 2017

In video content watching service, when a user requests video content, the content server has to transmit the entire video to the client for watching. This transmission delay increases as the size of video content increases. In order to solve the transmission delay problem, a prefetching technique can be used in which a video content to be watched by a user is predicted and transmitted to a client before the user requests it. In this paper, we propose a prefetching system considering multiple indices for video content. In the proposed method, video content to be prefetched is selected by comprehensively analyzing the order relation index indicating the order of viewing the videos of the users, the similarity index between the video contents, and the popularity index reflecting the viewing frequency of the video content. Experimental results show that the maximum accuracy is achieved when prefetching uses only the order relation index for movie contents.

• International Journal of Internet, Broadcasting and Communication
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• 제8권1호
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• pp.33-41
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• 2016

Big data management is becoming an increasingly important issue in both industry and academia of information science community today. One of the important categories of big data generated from software systems is log data. Log data is generally used for better services in various service providers and can also be used to improve system reliability. In this paper, we propose a novel big data management architecture specialized for log data. The proposed architecture provides a scalable log management system that consists of client and server side modules for efficient handling of log data. To support large and simultaneous log data from multiple clients, we adopt the Hadoop infrastructure in the server-side file system for storing and managing log data efficiently. We implement the proposed architecture to support various client environments and validate the efficiency through measurement studies. The results show that the proposed architecture performs better than the existing logging architecture by 42.8% on average. All components of the proposed architecture are implemented based on open source software and the developed prototypes are now publicly available.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3856-3872
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• 2018

HTTP-based adaptive streaming (HAS) has recently been widely deployed on the Internet. In the HAS system, a video content is encoded at multiple bitrates and the encoded video content is segmented into small parts of fixed durations. The HAS client requests a video segment and stores it in the playout buffer. The rate adaptation algorithm employed in HAS clients dynamically determines the video bitrate depending on the time-varying bandwidth. Many studies have shown that an efficient rate adaptation algorithm is critical to ensuring quality-of-experience in HAS systems. However, existing algorithms have problems estimating the network bandwidth because bandwidth estimation is performed on the client-side application stack. Without the help of transport layer protocols, it is difficult to achieve accurate bandwidth estimation due to the inherent segment-based transmission of the HAS. In this paper, we propose an alternative approach that utilizes the playout buffer occupancy rather than using bandwidth estimates obtained from the application layer. We start with a queueing analysis of the playout buffer. Then, we present a buffer-aware rate adaptation algorithm that is solely based on the mean buffer occupancy. Our simulation results show that compared to conventional algorithms, the proposed algorithm achieves very smooth video quality while delivering a similar average video bitrate.

• 한국콘텐츠학회논문지
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• 제10권12호
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• pp.342-351
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• 2010

본 연구의 목적은 아웃소싱을 통한 정보시스템 개발에서 고객사와 벤더 간에 발생하는 갈등의 주요 원인을 규명하는 것이다. 정보시스템 아웃소싱과 시스템 개발, 갈등에 관한 선행연구를 기반으로 연구모형을 설정하였으며, 고객사-벤더 쌍으로 이루어진 프로젝트 팀 단위의 설문 214개를 대상으로 PASW 18.0 통계패키지를 이용하여 실증연구를 수행하였다. 다중회귀분석을 이용한 통계분석결과, 계약의 구체성, 요구사항 불변성, 목표간 일치, 고객사의 지식이 갈등을 감소시키는 것으로 나타났다. 본 연구결과는 아웃소싱 프로젝트의 성과 향상을 위한 다양한 시사점을 제공할 것이다.

• 디지털콘텐츠학회 논문지
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• 제8권4호
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• pp.579-586
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• 2007

온라인 3D 게임 엔진 개발은 엔진 세부설계와 개발, 알파테스트, 수정 및 보완, 베타테스트, 출시 등의 개발 공정과정을 거치며, 온라인 3D 게임 엔진은 서버 엔진과 클라이언트 엔진으로 나뉜다. 서버 엔진은 Linux 에서 개발되며 비대칭 다중 서버 구축을 위한 서버구축 파트, 분산처리 파트, DB 구축파트로 각각 구성하고 클라이언트 엔진은 윈도우즈에서 DirectX 를 이용하여 개발하며 그래픽 파트, 사운드 파트, AI 파트, 객체처리 파트 파트로 각각 구성하고 엔진 공통기술인 네트워크 기술을 분석하여 3D엔진기술을 기반으로 엔진구조 및 구성하는 방식을 제안하였다.

• 가정간호학회지
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• 제23권2호
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• pp.243-252
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• 2016

Purpose: This study aims to classify multiple forms of home care services from a service user's perspective. By comparing the German system to the Korean one, this study seeks to find better ways of enhancing client-centered care. Methods: The data of 121 home care users were collected from six home care centers that had under the management of nursing managers for more than five years. The researcher used a German instrument to estimate the level of care. Results: High correlation was found between German and Korean assessment criteria (r=0.81, p<.001). However, compared to their German counterparts, Korean home care providers allocated more time towards provision of domestic help per daily visit. German home care providers allocated more time towards services relating to provision of support for physical activities, including personal hygiene. It was confirmed that the level of care in Korea does not correlate with either the categories of home care services and duration. Conclusion: Therefore, care services should be offered according to long-term care needs. This study suggests a need for systematic care aimed at strengthening the client's autonomy which should be properly planned, implemented, and managed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권3호
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• pp.886-905
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• 2012

Set-top Box (STB) has evolved from being a device just sitting on top of a TV shelf to a device providing a gateway to the Internet for a home network, receiving services from multiple content providers, and enabling and ensuring Quality of Service (QoS) for the streaming media. IP Multimedia Subsystem (IMS), with its promise to provide a converged access network for multimedia service delivery (such as Triple play & Quadruple play services), has to guarantee QoS support. To enable QoS in IMS-based networks, we have designed a set-top box which provides feedback to the service provider to ensure end-to-end QoS. Our set-top box is designed to provide virtual platforms such that it can support multiple service providers. Each service provider is able to manage its own multimedia streams and ensures the desired network performance for each flow. The set-top box also works as a Home Gateway and provides end-to-end QoS support to the client nodes.

• 한국IT서비스학회지
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• 제7권1호
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• pp.167-193
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• 2008

Clients' outsourcing strategies noted in the IT outsourcing literature generate varying levels of client dependence on vendors. This study investigates clients' efforts to mitigate such dependence by utilizing multiple vendors. We use the theoretical lenses of resource dependency and opportunism to study this phenomenon. Specifically. we consider degree of outsourcing, duration of contract, and externalization of control as strategic choices that engender vulnerabilities that clients seek to offset by using multiple vendors. This study then considers the basis of the outsourcing relationships, clients' satisfaction with the relationships. and clients' IT workforce size as conditions that induce clients' concerns about vendor opportunism. This study argues that these conditions can exacerbate clients' experience of vulnerability. further encouraging clients' use of multiple vendors. The research model developed is tested in a survey of firms in South Korea. Results suggest a strong impact of outsourcing strategic choices on the number of vendors used by clients. The anticipated moderating effects of opportunism were only weakly supported by the data though. Theoretical and practical implications of the results are considered and suggestions for future research are offered.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2023년도 춘계학술발표대회
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• pp.339-341
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• 2023

This paper presents a multithread and efficient cryptographic hardware access (MECHA) for efficient and fast cryptographic operations that eliminates the need for context switching. Utilizing a UNIX domain socket, MECHA manages multiple requests from multiple applications simultaneously, resulting in faster processing and improved efficiency. We comprise several key components, including the Server thread, Client thread, Transceiver thread, and a pair of Sender and Receiver queues. MECHA design is portable and can be used with any communication protocol, with experimental results demonstrating a 83% increase in the speed of concurrent cryptographic requests compared to conventional interface design. MECHA architecture has significant potential in the field of secure communication applications ranging from cloud computing to the IoT, offering a faster and more efficient solution for managing multiple cryptographic operation requests concurrently.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 춘계학술대회
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• pp.463-466
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• 2010

본 논문에서는 CCTV를 기반으로 한 화재 감시 시스템 개발을 위하여 기존 센서를 기반으로 하는 화재 탐지 시스템과 영상을 기반으로 하는 시스템들의 장단점을 분석하고 국가적으로 지원하고 있는 U-City, U-Home, U-Campus 등 확산되는 유비쿼터스 환경에 적합한 화재 감시 시스템 모델과 화재를 판별하기위한 기술을 제안한다. 본 연구를 위해 영상을 촬영할 카메라로는 Microsoft LifeCam VX-1000을 사용하였으며, 영상을 촬영하는 코덱으로는 H.264를 사용하였다. 카메라로부터 촬영된 영상 데이터를 가공하여 서버에 전달하는 클라이언트는 Linux OS를 사용하는 ARM9 S3C2440 보드로 제작하였다. 클라이언트와 서버의 영상 데이터 송/수신은 기본적으로 1:1 방식으로 되어있다. 그리하여 카메라의 데이터를 다중으로 수신하기 위한 멀티캐스트 1:N이 가능하게 명세하여, 화재 감시를 위한 다각적 영상 수신 시스템을 설계하였다. 영상 데이터는 RGB 형식을 YUV로 변환하여 전송하며, 화재를 감지하기위한 모션 추출을 위해 Y값을 이용한다. 화재 판별은 붉은 색상을 감지하고 Y값의 움직임을 계산해 화재시 지속적으로 타오르는 불꽃의 모션을 감지하여 판단하는 판별법을 적용한 시스템을 최종적으로 제안한다.