• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 가을 학술발표논문집 Vol.34 No.2 (D)
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• pp.494-499
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• 2007

애드 혹 유비쿼터스 컴퓨팅 환경의 가장 큰 특징은 연결의 역동성이다. 노드의 이동으로 인하여 두 노드를 연결하기 위한 경로를 지속적으로 재발견하여야 한다. 한편, 응용 계층에서도 사용자에게 현재의 상황에서 가장 적절한 서비스를 제공하기 위하여 연결된 서비스를 동적으로 재발견/재구성하게 된다. 이러한 환경에서는 이러한 재발견의 부담을 줄이는 것이 중요하다. 발견을 위한 비용이 응용 계층과 네트워크 계층에서 이중으로 발생하는 것을 회피하기 위하여 본 연구에서는 응용 계층의 레이블을 네트워크 계층에서 라우팅의 대상으로 사용하도록 제안한다. 물론 IP 주소에 기반한 라우팅도 동시에 지원한다. 본 연구에서는 IP 주소는 물론이고 응용 계층 레이블을 수용할 수 있는 공유된 라우팅 기법으로서 SGR(shared generic routing)을 제안한다. 시뮬레이션을 통하여 SGR이 발견의 비용을 효과적으로 줄 수 있음을 보였고 리눅스 운영 체제 환경에서 구현하여 실제 적용 가능성을 제시하였다.

• 한국언어정보학회:학술대회논문집
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• 한국언어정보학회 1995년도 Language, Information and Computation = Proceedings of the 10th Pacific Asia Conference, Hong Kong
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• pp.205-214
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• 1995

• 전자공학회논문지B
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• 제33B권5호
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• pp.41-51
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• 1996

In this paper, anew parallel processing system based on a cluster architecture which provides scalability of a parallel processing system while maintains shared memory multiprocessor characteristics is proposed. In recent days low cost, high performnce microprocessors have led to construction of large scale parallel processing systems. Such parallel processing systems provides large scalability but are mainly used for scientific applications which have large data parallelism. A shared memory multiprocessor system like TICOM is currently used as aserver for the commercial application, however, the shared memory multiprocessor system is known to have very limited scalability. The proposed architecture can support scalability and performance of the parallel processing system while it provides adaptability for the commerical application, hence it can overcome the limitation of the shared memory multiprocessor. The architecture and characteristics of the proposed system shall be described. A proprietary hierarchical crsossbar network is designed for this system, of which the protocol, routing and switching technique and the signal transfer technique are optimized for the proposed architecture. The design trade-offs for the network are described in this paper and with simulation usihng the SES/workbench, it is explored that the network fits to the proposed architecture.

• 한국경영과학회지
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• 제24권4호
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• pp.157-170
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• 1999

The web-based groupware systems hold many possibilities for system developers and users. Especially, web-based group collaborative systems are emerging as enterprise-wide information systems. Since data in group collaborative systems are apt to be shared among multiple concurrent users and modified simutaneously by them, the web-based group collaborative systems must support synchronous collaboration in order to provide users with synchronized and consistent views of shared data. However, current web technologies have limitations in supporting this, largely because the existing Hypertext Transfer Protocol(HTTP) is unidirectional and does not allow web servers to send messages to their web browsers without first receiving requests from them. This paper proposes an active web server that can overcome such limitations and facilitate synchronous collaboration in web-based group collaborative systems. To accomplish such goals, the active web server manages dependency relationships beween shared data and web browsers referencing them and actively propagates changing details of the shared data to all web browsers referencing them. And, this paper examines usefulness and effectiveness of the active web server to apply it to the ball-bearing design example of concurrent engineering design systems. The prototype system of the active web server is developed on a commercial Object-oriented Database Management System(0DBMS) called OBJECTSTERE using the C++ programming language.

• 산업공학
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• 제16권3호
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• pp.311-321
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• 2003

We propose the improved channel assignment and management methods for an efficient use of traffic channel resource for supporting 12.2 Kbps, 64 Kbps, and 384 Kbps traffic with the different quality of service(QoS) in the radio network controller(RNC) in asynchronous IMT-2000 system. We consider two types of traffic channel block assignments for utilizing the traffic channel efficiently; the Completely Shared(CS) channel assignment and the Partially Dedicated and Partially Shared(PDPS) channel assignment. The former is that all traffic channel blocks are completely shared with all traffic types. The latter is that some traffic channel block is independently assigned to each traffic type and the other blocks are completely shared with some traffic type. We also propose the traffic channel management method which consists of the block and task management step, for efficiently assigning, releasing, and managing the channel resource. Finally, we evaluate the performance through various numerical examples when applying our proposed channel block assignment and resource management methods.

• 대한간호학회지
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• 제42권4호
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• pp.453-465
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• 2012

Purpose: The study was done to develop a shared decision-making scale for end-of-life patients in Korea. Methods: The process included construction of a conceptual framework, generation of initial items, verification of content validity, selection of secondary items, preliminary study, and extraction of final items. The participants were 388 adults who lived in one of 3 Korean metropolitan cities: Seoul, Daegu, or Busan. Item analysis, factor analysis, criterion related validity, and internal consistency were used to analyze the data. Data collection was done from July to October 2011. Results: Thirty-four items were selected for the final scale, and categorized into 7 factors explaining 61.9% of the total variance. The factors were labeled as sharing information (9 items), constructing system (7 items), explanation as a duty (5 items), autonomy (4 items), capturing time (3 items), participation of family (3 items), and human respect (3 items). The scores for the scale were significantly correlated among shared decision-making scale, terminating life support scale, and dignified dying scale. Cronbach's alpha coefficient for the 34 items was .94. Conclusion: The above findings indicate that the shared decision-making scale has a good validity and reliability when used for end-of-life patients in Korea.

• 정보처리학회논문지B
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• 제12B권5호
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• pp.535-542
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• 2005

증강 협업 환경은 지리적으로 떨어진 그룹과 그룹간의 사용자들이 함께 어려운 문제를 풀 수 있도록 도와주는 다수의 디스플레이를 활용하는 작업 환경이다. 본 논문은 실시간 협력 작업 환경의 특징적인 공유 작업 공간 모델을 살펴본다 그리고 과학적 가시화를 위한 증강 협업 환경의 공유 작업 공간 모델을 검증하는 반복적인 디자인 실험연구를 설명하고 있다 이 연구에서 원거리 사용자들의 협업을 향상시키기 위한 증강 협업 환경의 디스플레이 기술 설정을 바꿔가며 사용자 평가 실험이 진행되었다. 각 실험에서 두 개의 방에 두 명씩 분산된 그룹들에게 협업 가시화를 이용한 집중적인 분석 작업을 시켰다. 그 결과 다른 사람들의 작업 내용을 쉽게 볼 수 있는 고화질 작업환경의 항시 가시성이 분산된 구성원들 간의 상호 인지도와 협력에 도움이 되어 협업 능률을 향상시켰다.

• Journal of Computing Science and Engineering
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• 제6권1호
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• pp.12-25
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• 2012

For real-time systems it is important to obtain the accurate worst-case execution time (WCET). Furthermore, how to improve the WCET of applications that run on multicore processors is both significant and challenging as the WCET can be largely affected by the possible inter-core interferences in shared resources such as the shared L2 cache. In order to solve this problem, we propose an innovative approach that adopts a code positioning method to reduce the inter-core L2 cache interferences between the different real-time threads that adaptively run in a multi-core processor by using different strategies. The worst-case-oriented strategy is designed to decrease the worst-case WCET among these threads to as low as possible. The other two strategies aim at reducing the WCET of each thread to almost equal percentage or amount. Our experiments indicate that the proposed multicore-aware code positioning approaches, not only improve the worst-case performance of the real-time threads but also make good tradeoffs between efficiency and fairness for threads that run on multicore platforms.

• ETRI Journal
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• 제31권6호
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• pp.784-794
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• 2009

We present a full HD (1080p) H.264/AVC High Profile hardware encoder based on fast motion estimation (ME). Most processing cycles are occupied with ME and use external memory access to fetch samples, which degrades the performance of the encoder. A novel approach to fast ME which uses shared multibank memory can solve these problems. The proposed pixel subsampling ME algorithm is suitable for fast motion vector searches for high-quality resolution images. The proposed algorithm achieves an 87.5% reduction of computational complexity compared with the full search algorithm in the JM reference software, while sustaining the video quality without any conspicuous PSNR loss. The usage amount of shared multibank memory between the coarse ME and fine ME blocks is 93.6%, which saves external memory access cycles and speeds up ME. It is feasible to perform the algorithm at a 270 MHz clock speed for 30 frame/s real-time full HD encoding. Its total gate count is 872k, and internal SRAM size is 41.8 kB.

• 전자공학회논문지CI
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• 제42권6호
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• pp.19-28
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• 2005

다중 프로세서 구조는 컴퓨터 성능을 향상시키기 위한 좋은 방법이다. 물리적으로 분산된 메모리를 단일 공유 메모리 공간으로 제공하는 CC-NUMA(Cache Coherent Non-Uniform Memory Access) 시스템은 다중 프로세서 컴퓨터 시스템으로 널리 사용된다. CC-NUMA는 공유 메모리 지원을 위해 풀맵 디렉토리를 가지며, 빠른 원격 메모리 접근을 위해 원격 캐시 메모리를 사용한다. 본 논문은 CC-NUMA 시스템을 구성할 수 있는 프로세싱 노드 구조와 이러한 구조에 적합한 캐시 일관성 유지 프로토콜을 제안하여, 대량의 프로세서를 이용한 다중 프로세서 시스템의 구성을 용이하게 한다. 끝으로 제안된 프로토콜에 따른 시스템 구현 결과도 제시한다.