• Resources Recycling
• /
• v.29 no.6
• /
• pp.35-40
• /
• 2020

In this study were carried out basic experiments mainly to investigate important reaction mechanism, the reaction temperature, time and the addition amount of Zn in recycling of waste cemented carbide by the zinc bath process. As a result, it was required that the Zn bath reaction was heated more than at 800℃ to accelerate reaction of melted Zn and Co inside of wasted cemented carbide. Furthermore, thickness of the waste cemented carbide was reduced linearly according to increase of reaction time at 700℃ for 0.5~2h in the zinc bath reaction. Also the zinc bath reaction was examined that heating in lower than at 800℃ for 3h and then heated more than at 900℃ for 1h(above 3.0×10 torr-2 vaccum) was suitable to reduce vapour loss amount of Zn in the zinc bath process.

• Journal of the Korean GEO-environmental Society
• /
• v.12 no.8
• /
• pp.33-38
• /
• 2011

Presently, domestic SCP method with low replacement ratio is required as alternative in order to overcome the profitability of the sand resource because of the deficiency phenomenon of the sand resource by the actual condition design and construction is made by SCP method with low replacement ratio more than 70% for the port construction in the safe side. Sand compaction pile(SCP) method has been mainly used to improve the properties of soft clay or loose sandy ground. In design of SCP at soft clay ground, it is very important to determine the stress concentration ratio of composite ground relevant to the area replacement ratio. In this study, 2-dimensional FEM analyses were carried out to evaluate the stress concentration ratio of composite ground depending upon the area replacement ratio. When the interpretation result replacement ratio was 30%, the stress assigned rate showed and as the replacement ratio was high, the stress assigned rate according to the sinkage showed the low stress assigned rate.

• Journal of Korea Water Resources Association
• /
• v.45 no.8
• /
• pp.805-814
• /
• 2012

Most hydrologic data are obtained by ground observations. New observation methods are needed for some regions to overcome difficulties in accessibility and durability of long-term observation. In 2002, NASA launched twin satellites named GRACE which were designed to measure the gravitational field of the earth. Using the GRACE monthly gravity level-2 data, we calculated terrestrial water storage change (TWSC) of the Korean peninsula in various spatial smoothing radii (0 km, 300 km, 500 km). For the validation of GRACE-based TWSC, we compared it with land-based TWSC which was obtained using the ground observation data: precipitation and evaporation from WAMIS, and runoff from GLDAS. According to the mean square-error test, GRACE-based TWSC best fits the land-based one at 500 km smoothing radius. The variation of the terrestrial water storage in the Korean peninsula turned out to be 0.986 cm/month, which means that appropriate measures should be prepared for sustainable water resources management.

• Korean Journal of Construction Engineering and Management
• /
• v.9 no.5
• /
• pp.159-167
• /
• 2008

This study provides a effective approach to the construction management problem with the limited number or amount of available resources using the analytic hierarchy process. Construction management is a series of decision making processes for planning and controling of cost, time and quality as main objectives in construction works. When several activities need the limited same resource at the same time, it is very hard to decide the priority of the activities in the real situations. For that the scientific decision making method and procedure for resource allocation are required. This study solves the resource allocation problem by dealing with the decision making problem which the activities are distributed to multiple projects and under multiple criteria. The analytic hierarchy process is a method devised to solve complex multi-criteria decision problems. The result shows that this study can be effectively used to make decisions in situations involving multiple objectives by evaluating the prioritized ranking and degree of the activity alternatives based on the overall preferences.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11a
• /
• pp.508-510
• /
• 2005

동영상 압축 표준인 H.264/AVC는 압축 효율을 높이기 위해 기존의 표준과는 다른 기법들을 사용함으로 압축률은 높였지만 보다 많은 계산량을 요구한다. 제한된 자원을 가진 임베디드 환경에서는 많은 계산량은 큰 문제점이 된다. DMB를 포함한 대부분의 경우는 이를 하드웨어적으로 구현을 하고 있지만 구현비용과 업데이트의 용의를 위해서 앞으로는 소프트웨어적으로도 구현이 가능해야 할 것이다. 본 논문에서는 H.264/AVC가 임베디드 환경에서 소프트웨어로 구현을 할 경우 그에 대한 성능 명가를 수행하기 위해 실제 임베디드 장비에서 H.264/AVC 복호기와 임베디드 그래픽 라이브러리를 사용해서 재생기를 구현하였고 다양한 종류의 영상을 재생시키는 실험을 하였다. 이러한 실험을 통해 임베디드 상에서 H.264/AVC 재생기는 QCIF 화면을 초당 3프레임 정도를 재생시키는 능력을 보였다. 이는 사용자측면에서는 동영상이라고 느낄 수 없을 정도의 성능이었다. 그러므로 임베디드 환경에서 H.264로 압축된 영상을 사용할 경우에는 H.264의 프로파일이나 레벨 조정 및 프레임 넘김 기법이 필요 할 것으로 추정한다.

• Journal of Digital Contents Society
• /
• v.13 no.1
• /
• pp.111-118
• /
• 2012

The burst is to require abruptly high transmission rate in case of transmitting pre-stored variable bit rate video data, and it causes to be inefficient use of network resource, resource reservation. To avoid these problems, smoothing is transmission plan where variable rate video data is converted to a constant bit rate stream. These smoothing algorithms include CBA, MCBA, MVBA and others. To evaluate amount of burst reduction in the existing CBA, MCBA, MVBA algorithm, this paper compares the burst-related-factors of transmission plan in smoothing algorithms with original video sources which were stored Variable Bit Rate. There are maximum frame bytes, maximum GOP bytes, transmission rate variability per frame, transmission rate variability per GOP in burst-related evaluation factors. Experimental result shows burst-related factors of smoothing algorithms which were used for experiment lower than that of pre-stored video data, except special case.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2015.07a
• /
• pp.444-446
• /
• 2015

컴퓨터 생성 홀로그램(CGH: computer generated hologram) 기법은 기존의 홀로그램의 광학적 장치의 단점을 보완하여 범용 컴퓨터에서 홀로그램을 생성할 수 있도록 하는 기술이다. CGH는 입력으로 주어지는 물체의 3차원 정보와 출력으로 나오는 디지털 홀로그램의 해상도에 따라 그 연산량이 결정 된다. CGH는 단순하고 반복적인 수학적 계산을 통하여 디지털 홀로그램을 생성하게 되는데, 기존의 연구들에서는 GPU(graphic processing unit)를 이용하여 알고리즘들을 병렬적으로 처리한다. 본 논문에서는 기존연구에서 쓰인 GPU를 이용한 CGH을 개선하여 GPU가 장착되지 않은 상용 컴퓨터에서 GPU가 장착된 다른 컴퓨터들의 연산 자원을 활용하여 CGH를 수행 할 수 있는 프로그램의 개발 방법을 제안 한다. 본 시스템은 GPU가 요구되지 않는 한 개의 서버 컴퓨터와 GPU가 장착된 다수의 클라이언트들로 구성되어 있다. 서버 측에서 물체의 3차원 정보를 입력 받아 각각의 클라이언트들에게 적절한 연산량을 분배하고, 각 클라이언트들은 이미 알려진 GPU 기반 CGH를 통하여 연산을 수행 한 뒤, 그 결과를 서버로 다시 전송하게 된다. 서버는 수신한 각 결과들을 누적하여 입력 받은 물체에 대한 하나의 온전한 홀로그램을 생성할 수 있게 된다.

• Journal of the Korea Society of Computer and Information
• /
• v.8 no.3
• /
• pp.156-162
• /
• 2003

With the network environment and user's application service increasing information protection and private information protection fields are very important fields. But it is necessary detection methodology to unspecified unknown signal, information increasing and various information media. Therefore in this thesis, we design NIDS that classify others information for detection of the unknown signal as the unauthenticated signal or illegal outer access, etc. proposed NIDS design used Synopsys Ver. 1999 and VHDL. The proposed NIDS system is practical in the system performance and cost for the individually existed NIDS, and utilized a part of system resources.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2011.06a
• /
• pp.67-70
• /
• 2011

본 논문에서는 고성능 컴퓨팅 시스템의 성능 향상을 위한 효율적인 동적 작업부하 균등화 정책을 제안한다. 이 정책은 시스템 자원인 CPU와 메모리를 효율적으로 사용하여 고성능 컴퓨팅 시스템의 처리량을 최대화하고, 각 작업의 수행시간을 최소화한다. 또한 이 정책은 수행중인 작업의 메모리 요구량과 각 노드의 부하 상태를 파악하여 작업을 동적으로 할당한다. 이때 작업을 할당 받은 노드가 과부하 상태가 되면 다른 노드로 작업을 이주시켜 각 노드의 작업부하를 균등하게 유지함으로써 작업의 대기시간을 줄이고, 각 작업의 수행시간을 단축한다. 본 논문에서는 시뮬레이션을 통하여 제안하는 동적 작업부하 균등화 정책이 기존의 메모리 기반의 작업부하 균등화 정책에 비해 고성능 컴퓨팅 시스템의 성능 향상 면에서 우수함을 보인다.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.5
• /
• pp.45-52
• /
• 2008

In this paper, we propose an efficient dynamic workload balancing strategy which improves the performance of high-Performance computing system. The key idea of this dynamic workload balancing strategy is to minimize execution time of each job and to maximize the system throughput by effectively using system resource such as CPU, memory. Also, this strategy dynamically allocates job by considering demanded memory size of executing job and workload status of each node. If an overload node occurs due to allocated job, the proposed scheme migrates job, executing in overload nodes, to another free nodes and reduces the waiting time and execution time of job by balancing workload of each node. Through simulation, we show that the proposed dynamic workload balancing strategy based on CPU, memory improves the performance of high-performance computing system compared to previous strategies.