• 전자공학회논문지C
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• 제36C권4호
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• pp.1-16
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• 1999

본 논문에서는 테스트 생성 과정에서 자주 사용되는 임계의 확장 개념으로 임계-쌍을 정의한다. 그리고 임계의 특성을 나타내는 요소로서 임계성, 임계율, 임계설정율 등을 정의한다. 이 요소들을 이용하여 임계-쌍의 사용이 단일 임계의 사용보다 더 효율적이라는 것을 입증하고, FFR에서의 테스트 패턴 생성 시에 임계값에 대한 평가 회수, 경로선의 탐색 회수 및 생성 시간에서 더 효율적이라는 것을 보여준다. 시뮬레이션을 통해서 ISCAS85 벤치마크 테스트 회로에 대한 실험 결과를 비교 분석한다.

• 스마트미디어저널
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• 제4권1호
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• pp.25-32
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• 2015

Powering wireless sensors with energy harvested from the environment is coming of age due to the increasing power densities of both storage and harvesting devices and the electronics performing energy efficient energy conversion. In order to maximize the functionality of the wireless sensor network, minimize missing packets, minimize latency and prevent the waste of energy, problems like congestion and inefficient energy usage must be addressed. Many sleep-awake protocols and efficient message priority techniques have been developed to properly manage the energy of the nodes and to minimize congestion. For a WSN that is operating in a strictly energy constrained environment, an energy-efficient transmission strategy is necessary. In this paper, we present a novel transmission priority decision scheme for a heterogeneous body sensor network composed of normal nodes and an energy harvesting node that acts as a cluster head. The energy harvesting node's decision whether or not to clear a normal node for sending is based on a set of metrics which includes the energy harvesting node's remaining energy, the total harvested energy, the type of message in a normal node's queue and finally, the implementation context of the wireless sensor network.

• 한국CDE학회논문집
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• 제16권2호
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• pp.92-103
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• 2011

The construction industry consists of various and massive architectural information as an architectural process includes a variety of design stages with cooperation of many disciplines. A Building Information Modeling (BIM) serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle from inception onward. building SMART has developed Industry Foundation Classes (IFC) standard for interoperability of BIM based information. Several software tools are already IFC-compliant. However, there are a lot of problems related to efficient interoperability of software owing to the lack of guide regarding the software usage and insufficiency IFC interfaces of software. The purpose of this study is to suggest efficient IFC support interface development methodologies of existing IFC certified software. The scope of this study is interoperability test for open BIM based quality assurance. To achieve this purpose, the authors have classified subject of open BIM based quality assurance and investigated IFC certification process and certified software. In addition, the authors have exported and imported via IFC files using different IFC interfaces in the software for interoperability of architectural objects and their properties. Finally, the authors have suggested IFC support interface development methodologies and hereafter direction for efficient interoperability of IFC certified software based on open BIM.

• 상하수도학회지
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• 제29권3호
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• pp.415-425
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• 2015

Aging water pipe networks hinder efficient management of important water service indices such as revenue water and leakage ratio due to pipe breakage and malfunctioning of pipe appurtenance. In order to control leakage in water pipe networks, various methods such as the minimum night flow analysis and sound waves method have been used. However, the accuracy and efficiency of detecting water leak by these methods need to be improved due to the increase of water consumption at night. In this study the Principal Component Analysis (PCA) technique was applied to the night water flow data of 426 days collected from a water distribution system in the interval of one hour. Based on the PCA technique, computational algorithms were developed to narrow the time windows for efficient execution of leak detection job. The algorithms were programmed on computer using the MATLAB. The presented techniques are expected to contribute to the efficient management of water pipe networks by providing more effective time windows for the detection of the anomaly of pipe network such as leak or abnormal demand.

• 전기학회논문지
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• 제65권3호
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• pp.428-438
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• 2016

This paper shows the design of the 100 kW IPMSG for small hydraulic power generator. The high-efficient generator, method of the dual layer interior permanent magnet was studied to improve the method of the single layer interior permanent magnet, which is mostly used. Analysis of magnet arrangement and cogging torque was done by FEM. According to structure analysis of dual layer interior permanent magnet, the amount of usage of the permanent magnet was reduced and cogging torque was decreased as well. With these successful results, the high-efficient generator design was accomplished. Based on the results of the structure analysis, the test product was designed and manufactured. And the design values and performance outputs were compared and verified with success. Also, the economic feasibility was conducted based on the electric power generated from the test product installed at the site. By the B/C analysis, in case that only SMP was analyzed, B/C ratio was 1.24 at the discount ratio of 5.5%, which considered to be economically feasible. The study is expected to be used for the application of developing large scale high-efficient interior permanent magnet synchronous generator.

• 한국컴퓨터산업학회논문지
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• 제7권3호
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• pp.217-226
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• 2006

멀티미디어 스트림은 일반적으로 용량이 크고, 서로 다른 미디어간의 동기화가 필요하며 실시간으로 재생되어져야 한다는 특징이 있다. 그러므로 N-VOD 서버에 관계된 연구는, 궁극적으로 디스크 대역폭이나 버퍼의 크기 등 서버의 주어진 자원 한계 아래에서 얼마만큼 사용자의 수를 최대화 하느냐에 주된 관심이 되고 있다. 본 논문에서는 효율적인 멀티미디어 서비스를 위하여 서버의 자원을 관리하여 효율적으로 서비스를 할 수 있는 VCR 조작이나 버퍼 및 디스크 관리정책을 제안한다. 시뮬레이션 해본 결과 전통적인 방식보다 버퍼의 활용과 서비스 처리시간에서 약 18% 정도 향상된 성능을 보였는데, 이는 서비스 사용자의 수를 증가 시키는 문제와 밀접한 관련이 있다.

• 한국컴퓨터산업학회논문지
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• 제6권3호
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• pp.379-390
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• 2005

멀티미디어 스트림은 일반적으로 용량이 크고, 서로 다른 미디어간의 동기화가 필요하며, 실시간으로 재생되어져야 한다는 특징이 있다. 그러므로 VOD 서버에 관계된 연구는, 궁극적으로 디스크 대역폭이나 버퍼의 크기 등 서버의 주어진 자원 한계 아래에서 얼마만큼 사용자의 수를 최대화 하느냐에 주된 관심이 되고 있다. 본 논문에서는 효율적인 멀티미디어 서비스를 위하여 서버의 자원을 동적으로 모니터하고 관리하여 효율적으로 서비스를 할 수 있는 선반입 관리정책을 제안한다. 시뮬레이션 해본 결과 전통적인 방식보다 버퍼의 활용과 서비스 처리시간에서 약 $20\%$ 정도 향상된 성능을 보였는데, 이는 서비스 사용자의 수를 증가시키는 문제와 밀접한 관련이 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.291-304
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• 2019

This paper proposes a dynamic-tiling-based bandwidth-efficient (DTBE) virtual reality (VR) streaming scheme. We consider 360-degree VR contents with multiple view points such as the front, back, upper, and bottom sides. At a given time, the focus of a client is always bound to a certain view among multiple view points. By utilizing this perspective, under our proposed scheme, tiles with high encoding rates are selectively assigned to the focused view where multiple view points consist of multiple tiles with different encoding rates. The other tiles with low encoding rates are assigned to the remaining view points. Furthermore, for reducing view adaptation delay, we design a novel rapid view adaptation mechanism that selectively delivers an I-frame during view point updates by using frame indexing. We implement the proposed scheme on a commercial VR test bed where we adopt the MPEG media transport (MMT) standard with high-efficiency video coding (HEVC) tile modes. The measurement-based experiments show that the proposed scheme achieves an average data usage reduction of almost 65.2% as well as average view adaptation delay reduction of almost 57.7%.

• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.45-49
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• 2022

The fourth industrial revolution, internet of things, and the expansion of online web services have increased an exponential growth and deployment in the number of cloud data centers (CDC). The cloud is emerging as new paradigm for delivering the Internet-based computing services. Due to the dynamic and non-linear workload and availability of the resources is a critical problem for efficient workload and resource management. In this paper, we propose the particle swarm optimization (PSO) based gated recurrent unit (GRU) neural network for efficient prediction the future value of the CPU and memory usage in the cloud data centers. We investigate the hyper-parameters of the GRU for better model to effectively predict the cloud resources. We use the Google Cluster traces to evaluate the aforementioned PSO-GRU prediction. The experimental shows the effectiveness of the proposed algorithm.

• 국제초고층학회논문집
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• 제12권2호
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• pp.107-120
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• 2023

Tall buildings are frequently decried as unsustainable due to their excessive energy usage. Early skyscrapers used natural light and ventilation to facilitate human comfort and applied organic materials such as stone, glass, wood, concrete, and terra cotta for cladding and finishes. With the advent of fluorescent lighting, modern heating, ventilation, air-conditioning (HVAC) systems, and thermally sealed curtain walls, tall office buildings no longer had to rely on natural light and ventilation to provide comfort. Energy efficiency was not a significant factor when the operational costs of buildings were relatively inexpensive. However, today's skyscrapers must become more energy-efficient and sustainable due to energy crises and climate change. This paper highlights vital energy-efficient design principles and demonstrates with illustrative case studies how they are applied to tall buildings in various parts of the world. It shows how sustainable environmental systems do not act alone but are integrated with advanced curtain wall systems, sky gardens, and atria, among others, to regulate and sustain thermal comfort and conserve energy.