• Journal of KIISE
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• v.43 no.8
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• pp.841-847
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• 2016

As network technology advances, a larger number of devices are connected through the Internet. Recently, cloud storage services are gaining popularity, as they are convenient to access anytime and anywhere. Among cloud storage services, object storage is the representative one due to their characteristics of low cost, high availability, and high durability. One limitation of object storage services is that they can access data on the cloud only through the HTTP-based RESTful APIs. In our work, we resolve this limitation with the in-memory file system which provides a POSIX interface to the file system users and communicates with cloud object storages with RESTful APIs. In particular, our flush mechanism is compatible with existing file systems, as it is based on the swap mechanism of the Linux kernel. Our in-memory file system backed by cloud storage reduces the performance overheads and shows a better performance than S3QL by 57% in write operations. It also shows a comparable performance to tmpfs in read operations.

• The KIPS Transactions:PartC
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• v.18C no.3
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• pp.143-150
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• 2011

The adoption of VoIP is continuously increasing in public institutions, private enterprises and households due to cheaper cost and various supplementary services. Also, it is expected to spread widely the use of VoIP in mobile environment through the increasing use of smartphone. With the growing concern over the incidents of VoIP service while the VoIP service has become increasingly. Especially eavesdropping, it is possible to invade user privacy and drain the secret of company. So, it is important to adopt the protocols for VoIP secure communication. VoIP security protocols are already adopted in public institutions, but it is not adopted in private enterprises and households. In addition, it is necessary to verify whether the VoIP security protocol could be adopted or not in mobile VoIP due to its limited computing power. This paper compared the VoIP security protocol under fixed network and mobile network through performance evaluation. Finally, we found that it is possible to adopt the VoIP security protocols in mobile network.

• Korean Journal of Construction Engineering and Management
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• v.8 no.2
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• pp.75-83
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• 2007

Recently, the Design-Build (DB) delivery method in public sector makes some argument by reason of the initial cost which is more higher than those of Design-Bid-Build (DBB). According to the results of pervious researches related to the performance evaluation of delivery method, DB can lead the reduction of project cycle time and also is superior to the traditional DBB in terms of construction quality. The performance on each delivery method could be generally evaluated by a project cost and a project cycle time as one of quantitative analyses, and also by construction quality as one of qualitative analyses. In most researches, the evaluation of performance level based on delivery methods has been evaluated by the degree of their satisfaction through the interview with owners. Therefore, this paper analyzed the design documents of construction projects delivered by traditional DBB and DB in bridge construction projects in order to measure design quality, constructability, maintainability, and etc. As an above-mentioned analyses, finally, this research shown that how much the difference of performance level is by each delivery method.

• KIEAE Journal
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• v.17 no.5
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• pp.25-31
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• 2017

Purpose: Currently, there are many success stories coming out various energy-saving / production or eco-friendly buildings. However, these case and method didn't consider of application with existing housing and high-rise housings. In the case of Europe, the North America is gradually grew and settle through the voluntary, small, private development. But this method and system are not fit for the majority of developing countries including South Korea. Method: In this situation, this paper analyse, first arranged previous research and case study, second divided factors and re-organized factors, third analysed plan and elevation of apartment and selected main plan type and elevation type of apartment, finally analysed method of application with existing buildings and high-rise buildings by test and simulation. Result: In sum, this research finally analyzed the change of electricity and fuel consumption according to the change of insulation standard. This study has been expected to serve as a bridge of the energy housing system development and suggest new method applied to the existing housing and building.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.117-122
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• 2001

The shock test of shipboard equipments is performed for the evaluation of the shock-resistant. capability by analyzing the maximum acceleration, the effective time duration and the shock response spectrum, etc. But some measured signals have impulsive noise and gaussian white noise because of the ambient noise, the acquisition equipment error and the transient movement of cables during the shock test. The improved transient signal analysis method which removes the noise of measured signal using the threshold policy of the median filter and the orthogonal wavelet coefficients is proposed. It was verified that the signal-to-noise ratio was improved about 30dB by the numerical simulation. And the shock response spectrum was extracted using the denoised shock response signal which was applied by this proposed method.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.06a
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• pp.233-239
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• 2001

최근 대부분의 회사들은 업무를 수행하는데 필요한 지식과 노하우를 공유하고 재사용하기 위하여 지적 자산 관리의 중요성을 인식하고 있다. 특히 고도로 지식 집약적인 업종이라 할 수 있는 IT컨설팅 회사에서는 지적 자산의 관리가 다른 어떤 회사에서보다 큰 중요성을 가지게 된다. 컨설팅 회사에 있어서 검증이 완료된 지적 자산의 공유 및 지능적이면서도 신속한 검색은 컨설팅 서비스의 품질과 고객 만족에 직결되는 중요한 요소이다. 따라서 대부분의 컨설팅 회사들은 자사의 지식 자산을 관리하기 위하여 많은 노력을 기울이고 있다. 본 논문의 목적은 IT 컨설팅 회사예서 관리되는 다양한 형태의 지적 자산들을 중앙 관리하여 설친 고객 사이트에 흩어져 프로젝트를 수행하는 컨설턴트들이 공유할 수 있도록 함으로써 컨설팅 서비스의 생산성과 품질들 높이고자 하는데 있다 이를 위하여 건설팅 회사에서 관리되는 모든 지적 자산의 재고를 조사하여 모델링하고 이를 쉽게 저장하고 검색할 수 있는 시스템 아키텍처를 제안한다. 제안된 아키텍처를 NT 기반에서 Index server를 이용하여 시스템으로 구현하였다 (KMSCR: A Knowledge Management System for managing Consulting Resources). KMSCR에서는 컨설턴트가 찾고자 하는 검색어를 입력하면 다양한 포맷의 (.doc, .ppt, xls, .rtf, .txt, .html 등과 같은) 결과물을 관련성이 높은 순서대로 출력해 줌으로써 컨설팅 리소스를 효과적으로 재사용할 수 있도록 도와 준다. 또한 검색 시에는 미리 등록된 키워드 뿐 아니라 본문 내의 텍스트 검색까지 가능하게 함으로써 컨설팅 리소스에 대한 보다 효과적이고 효율적인 검색을 가능하게 한다.간을 성능 평가 인자로 하여 수행하였다. 논문에서 제한된 방법을 적용한 개선된 RICH-DP을 모의 실험을 통하여 분석한 결과 기존의 제한된 RICH-DP는 실시간 서비스에 대한 처리율이 낮아지며 서비스 시간이 보장되지 못했다. 따라서 실시간 서비스에 대한 새로운 제안된 기법을 제안하고 성능 평가한 결과 기존의 RICH-DP보다 성능이 향상됨을 확인 할 수 있었다.(actual world)에서 가상 관성 세계(possible inertia would)로 변화시켜서, 완수동사의 종결점(ending point)을 현실세계에서 가상의 미래 세계로 움직이는 역할을 한다. 결과적으로, IMP는 완수동사의 닫힌 완료 관점을 현실세계에서는 열린 미완료 관점으로 변환시키되, 가상 관성 세계에서는 그대로 닫힌 관점으로 유지 시키는 효과를 가진다. 한국어와 영어의 관점 변환 구문의 차이는 각 언어의 지속부사구의 어휘 목록의 전제(presupposition)의 차이로 설명된다. 본 논문은 영어의 지속부사구는 논항의 하위간격This paper will describe the application based on this approach developed by the authors in the FLEX EXPRIT IV n$^{\circ}$EP29158 in the Work-package "Knowledge Extraction & Data mining"where the information captured from digital newspapers is extracted and reused in tourist information context.terpolation performance of CNN was relatively

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.119-119
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• 2010

무한 지속 가능한 지열 에너지를 활용한 공조시스템인 지열원 냉난방 시스템은 기존의 공조 시스템보다 열원이 안정적이기 때문에 높은 효율과 우수한 성능을 가지므로, 기후변화협약 대응의 주요수단으로서 기술개발과 보급이 증대되고 있다. 본 연구에서는 대수층 축열 지열원 열펌프 시스템에 대한 실증 연구를 통하여 대수층 축열 지열원 열펌프 시스템의 하절기 냉방 성능을 분석하였다. 대수층 축열 냉난방 시스템은 주입정과 양수정의 2개의 우물공이 설치되어 있으며, 겨울 난방 운전 중에 한 개의 우물공으로부터 지하수를 열펌프로 유입한 후 낮은 온도의 지하수를 타 우물공에 축열하고, 하절기에 겨울에 저온으로 축열된 우물공으로부터 지하수를 열펌프로 유입하여 온도가 증가된 지하수를 타 우물공에 주입한다. 즉, 계절별로 열펌프에서 생성된 냉수와 온수의 대수층 축열을 위하여 계절별로 주입정과 양수정이 바뀌게 된다. 본 연구의 대수층 축열 지열원 열펌프 시스템의 2009년 8월의 주요일자별 시스템 운전 중의 평균 냉방 열펌프 유닛 COP와 냉방 시스템 COP는 각각 4.7과 3.4이상의 우수한 성능을 나타냈다. 또한, 모든 일자에 대하여 외기온도가 $31.6^{\circ}C$서 $22^{\circ}C$까지 변화가 크게 나타났지만 열펌프 유닛 COP와 시스템 COP의 변화는 미소하였다. 이는 양수정으로부터의 지중 순환수가 운전기간 중에 $17.5^{\circ}C$로 일정하게 유지되었기 때문이다. 양수정과 주입정 사이에 5개의 관측공을 설치하였으며, 양수정 측에 인접한 관측공의 온도는 거의 변화가 없었으며, 단기간이지만 널리 사용되고 있는 수직밀폐형 시스템과 달리 지속적인 냉방운전 중의 양수 온도의 증가는 발생하지 않아 안정적인 성능을 나타냈다. 주입정에 인접한 모니터링 홀의 온도는 심도가 깊은 곳의 온도가 낮은 곳보다 높게 나타났다. 이는 냉방 운전 시 열펌프 유닛의 실외열교환기에서 지중 순환수가 냉매로부터 열을 취득하여 온도가 상승하면서 주입정측에 온열이 축열이 진행되었기 때문으로 분석되며, 하절기의 냉방 운전 시간이 증가할 경우 축열 효과는 더욱 증가할 것으로 예상된다. 양수정과 주입정 중간의 모니터링 홀의 온도는 2009년 8월 가동 중에 온도변화는 없었는데, 이는 양수정과 주입정 사이의 열간섭이 발생하지 않았기 때문으로 분석된다. 일자별로 운전 중의 열펌프 유닛 COP는 차이가 없었지만, 운전 및 정지 시간을 모두 포함한 시스템 소비전력과 냉방용량을 모두 합산하여 산정한 일일 평균 냉방 열펌프 유닛 COP와 냉방 시스템 COP는 일자별로 다소 차이가 발생하였는데, 이는 각 일자별로 열펌프 유닛 가동율의 차이로 인하여 열펌프 유닛 가동 전에 먼저 작동되는 지중순환펌프의 운전 소비전력의 차이와 열펌프의 단속운전 시의 열손실과 추거 소비전력의 차이 때문이다.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.5
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• pp.33-42
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• 2012

This study aims to establish the performance standard for natural type landscape stone GFRC. The required performance such as material performance, structural safety performance, durability performance, and landscape performance were selected through an examination of domestic and overseas performance related references and examples, and through the questionnaires obtained from 40 experts, and the verified items and performance standards were proposed. Among the required performances, the material performance(glass fiber content, air-dried gravity), structural safety performance(flexural strength, compressive strength), durability performance(crack, corrosion resistance), and landscape performance(texture, efflorescence) were selected through the questionnaires obtained from the experts. In the case of material performance and structural safety performance with the corresponding standards that existed, final performance evaluation standard was proposed by conducting a test and comparing it with the existing standard sample, and in the case of durability performance and landscape performance on which standard does not existed, they were verified by measuring directly through field examination of formative landscape items such as artificial waterfall etc. In this study, performance standard for the material on natural type landscaping rocks GFRC and items which can be evaluated after construction such as material performance, structural safety performance, durability performance, landscape performance, and so forth were proposed, however, follow up study for pro-environmental and ecological performance standard which were recently gaining force would be required through a continuous monitoring for the construction samples afterwards.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.10-18
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• 2022

Purpose: For smooth performance of flood analysis due to heavy rain disasters at energy storage facilities in the Incheon area, field surveys, observational surveys, and pre-established reports and drawings were analyzed. Through the field survey, the characteristics of pipelines and rivers that have not been identified so far were investigated, and based on this, the input data of the SWMM model selected for inundation analysis was constructed. Method: In order to determine the critical duration through the probability flood analysis according to the calculation of the probability rainfall intensity by recurrence period and duration, it is necessary to calculate the probability rainfall intensity for an arbitrary duration by frequency, so the research results of the Ministry of Land, Transport and Maritime Affairs were utilized. Result: Based on this, the probability of rainfall by frequency and duration was extracted, the critical duration was determined through flood analysis, and the rainfall amount suggested in the disaster prevention performance target was applied to enable site safety review. Conclusion: The critical duration of the base was found to be a relatively short duration of 30 minutes due to the very gentle slope of the watershed. In general, if the critical duration is less than 30 minutes, even if flooding occurs, the scale of inundation is not large.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.98-106
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• 2013

In this paper, we propose a moving object detection and tracking method for multi-view camera environment. Based on the similarity and characteristics of motion vectors and coding block modes extracted from compressed bitstreams, validation of moving blocks, labeling of the validated blocks, and merging of neighboring blobs are performed. To continuously track objects for temporary stop, crossing, and overlapping events, a window based object updating algorithm is proposed for single- and multi-view environments. Object detection and tracking could be performed with an acceptable level of performance without decoding of video bitstreams for normal, temporary stop, crossing, and overlapping cases. The rates of detection and tracking are over 89% and 84% in multi-view environment, respectively. The rates for multi-view environment are improved by 6% and 7% compared to those of single-view environment.