• 대한교통학회지
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• 제29권4호
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• pp.7-15
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• 2011

도심 교통체증 감소와 물류의 신속한 이동을 위해 1990년대 초반 등장한 퀵서비스산업은 이륜자동차의 증가를 가속화 했으며, 경제발전에 따라 250CC 이상 대배기량의 이륜자동차들도 레저용으로 급증하고 있는 추세를 보이고 있다. 사고발생추세에서 전체교통사고대비 2005년 5.7%, 2008년 8.3%로 점차 증가추세를 보이며 사망률 또한 증가하고 있다. 본 연구에서는 이륜자동차의 자동차전용도로 통행에 대한 위험도를 알아보고자 서울시 연속류 도로를 대상으로 이륜자동차의 법규위반율과 차로변경 행태, 주행속도 행태를 분석하였으며 사고시의 차량충격량을 PCCRASH 시뮬레이션으로 산출하였다. 분석 결과, 차로변경시간과 평균통행속도가 일반차량과 상이하며 도로정체가 발생할 경우 부적절한 주행행태를 보이는 것으로 나타났다. 정부의 이륜자동차 자동차전용도로 허용 검토에 있어 본 연구는 허용여부를 판단하는데 도움이 되며 이륜자동차의 주행 행태를 연구하는데 기초자료로 활용할 수 있다.

• Steel and Composite Structures
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• 제35권5호
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• pp.627-634
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• 2020

The past years were marked by an increase in the use of wood waste in civil and mechanical constructions. Date palm waste remains also one of the most solicited renewable and recyclable natural resources in the composition of composite materials. In Algeria, a great amount of this type of plant wastes accumulates every year. In order to make use of this waste, a new wood-epoxy composite material based on date palm petiole particleboard is developed. It makes use of date palm petiole particleboard as reinforcement and epoxy resin as matrix. The size of the particles reinforcement are between 1~3 mm and proportion of reinforcement used is 37%. In this work, experimental and numerical studies are conducted in order to characterize the wood fibre-epoxy plates. Firstly, experimental modal analysis test was carried out to determine Young's modulus of the elaborated material. Then, in order to validate the results, compression test was conducted. Furthermore, additional information about the shear modulus of this material is obtained by performing an experimental modal analysis to extract the first torsional mode. Moreover, a finite element model is developed using ANSYS software to simulate the vibration behaviour of the plates. The results show a good agreement with the experimental modal analysis, which confirms the values of Young's modulus and shear modulus.

• 한국의류학회지
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• 제20권6호
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• pp.1048-1061
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• 1996

The most important practical feature that represents the performance of a washing machine is its ability to remove stains or soils from clothes. There are various tests to measure a washing machine's ability to remove stains or soils from clothes. The results of these tests are dependent upon the kind of soiled fabrics used. Moreover, these results may reflect some aspects of the effectiveness of a washing machine in cleaning clothes due to the paritcular compositions of chemicals which comprise soils in soiled fabrics and the particular conditions in which the results are evaluated. After selecting factors presumed to have a major effect on the cleaning ability of a washing machine and choosing most widely used soiled fabrics, we use experimetal statistics methods to screen real factors from them that influence the cleaning ability of a washing machine in a statistically significant manner for each soiled fabric. Using the least number of experimental rules required to extract the necessary information, we then proceed to present the study on the relations between the sets of selected factors and the soiled fabrics. We would then suggest which soiled fabrics is the best for evaluating the performance in cleaning clothes of a washing machine based on the above study.

• Journal of Communications and Networks
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• 제5권2호
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• pp.104-115
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• 2003

It is well known that Multiple Input Multiple Output (MIMO) systems offer the promise of achieving very high spectrum efficiencies (many tens of bit/s/Hz) in a mobile environment. The gains in MIMO capacity are sensitive to the presence of spatial and temporal correlation introduced by the radio environment. In this paper, we examine how MIMO capacity is influenced by a number of factors e.g., a) temporal correlation b) various combinations of low/high spatial correlations at either end, c) combined spatial and temporal correlations. In all cases, we compare the channel capacity that would be achievable under independent fading. We investigate the behaviour of "capacity fades," examine how often the capacity experiences the fades, develop a method to determine level crossing rates and average fade durations and relate these to antenna numbers. We also evaluate the influence of channel correlation on the capacity autocorrelation and assess the fit of a Gaussian random process to the temporal capacity sequence. Finally we note that the particular spatial correlation structure of the MIMO channel is influenced by a large number of factors. For simplicity, it is desirable to use a single overall correlation measure which parameterizes the effect of correlation on capacity. We verify this single parameter concept by simulating a large number of different spatially correlated channels.

• Nuclear Engineering and Technology
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• 제39권5호
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• pp.627-636
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• 2007

The present work is aimed at further discussing the effectiveness of dimensionless parameters recently proposed for the analysis of flow stability in heated channels with supercritical fluids. In this purpose, after presenting the main motivations for the introduction of these parameters in place of previously proposed ones, additional information on the theoretical bases and on the consequences of this development is provided. Stability maps, generated by an in-house program adapted from a previous application to boiling channels, are also shown for different combinations of the operating parameters. The maps are obtained as contour plots of an amplification parameter obtained from numerical discretization and subsequent linearization of governing equations; as such, they provide a quantitatively clear perspective of the effect of different boundary conditions on the stability of heated channels with supercritical fluids. In order to assess the validity of the assumptions at the basis of the in-house model, supporting calculations have been performed making use of the RELAP5/MOD3.3 computer code, detecting the values of the dimensionless parameters at the threshold for the occurrence of instability for a heated channel representative of SCWR proposed core configurations. The obtained results show reasonable agreement with the maps, supporting the applicability of the proposed scaling parameters for describing the dynamic behaviour of heated channels with supercritical fluids.

• 한국BIM학회 논문집
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• 제8권4호
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• pp.72-79
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• 2018

Rapid developments around the world have resulted in urban expansion, habitat destruction, habitat fragmentation, and pollution problems, which are the main reasons for the decline in biological diversity. The United Nations warns that many animals and plants will die out in the near future if this continues. This study was performed to propose a map of eco-corridor suitability analysis of Korean water deer(Hydropotes Inermis) to enhance biodiversity in Chuncheon city. Eight factors affecting habitat suitability were elevation, aspect, slope, forest type, distance to the road, distance to the stream, land use and green connectivity. Previous study analysis on the mobility behaviour of the Korean water deer(Hydropotes Inermis) produced a habitat suitability map by determining the threshold and assigning a value between 0 and 1 depending on the habitat suitability using the fuzzy function. A method of analysis was proposed for a number of eco-corridor through comparative analysis of the data from the produced habitat suitability map and the road-kill point. The previous studies were focused on Backdudaegan region and national parks except for urban cities. The potential habitat map of Korean water deer could be helpful as a way to prevent habitat disconnection and increase species diversity in urban areas.

• 한국재난정보학회 논문집
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• 제13권1호
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• pp.81-88
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• 2017

이 논문에서는 강재 보와 보강을 위하여 부착한 탄소섬유판의 동일거동을 분석하기 위하여 시험과 유한요소해석을 수행하고, 시험 및 해석 결과를 이용한 분석을 실시하였다. 현재 국내외의 연구에서는 복합재료를 사용한 보수 보강 복구에 대한 사용검토가 많이 연구되어지는 실정에서 섬유보강 복합재료는 얇고 강도가 좋으며 가벼워 구조물의 보강 시에 사하중의 증가를 발생시키지 않고 부재의 치수 증가에도 영향이 없어 매우 유용한 재료로 부각된다. 그러나 노후화에 따른 부착력 저하 등의 문제와 경제성 및 설계상의 어려움으로 사용이 극히 제한적인 부분이다. 이 연구에서는 탄소섬유판이 부착된 단순한 강재보의 성능을 평가하였으며, 부착성능 측면에서는 양호한 사용성능을 가지는 것으로 나타났다. 향후 노후화에 대한 검토가 수행된다면 실제 구조물에 대한 적용에도 문제가 없을 것으로 판단된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6214-6242
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• 2019

Routing in mobile ad hoc networks is performed in a distributed fashion where each node acts as host and router, such that it forwards incoming packets for others without relying on a dedicated router. Nodes are mostly resource constraint and the users are usually inclined to conserve their resources and exhibit selfish behaviour by not contributing in the routing process. The trust and reputation models have been proposed to motivate selfish nodes for cooperation in the packet forwarding process. Nodes having bad trust or reputation are detected and secluded from the network, eventually. However, due to the lack of proper identity management and use of non-persistent identities in ad hoc networks, malicious nodes can pose various threats to these methods. For example, a malicious node can discard the bad reputed identity and enter into the system with another identity afresh, called whitewashing. Similarly, a malicious node may create more than one identity, called Sybil attack, for self-promotion, defame other nodes, and broadcast fake recommendations in the network. These identity-based attacks disrupt the overall detection of the reputation systems. In this paper, we propose a reputation-based scheme that detects selfish nodes and deters identity attacks. We address the issue in such a way that, for normal selfish nodes, it will become no longer advantageous to carry out a whitewash. Sybil attackers are also discouraged (i.e., on a single battery, they may create fewer identities). We design and analyse our rationale via game theory and evaluate our proposed reputation system using NS-2 simulator. The results obtained from the simulation demonstrate that our proposed technique considerably diminishes the throughput and utility of selfish nodes with a single identity and selfish nodes with multiple identities when compared to the benchmark scheme.

• 한국재난정보학회 논문집
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• 제19권2호
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• pp.262-269
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• 2023

연구목적: 터널에서 발생되는 화재로 인하여 구조물의 피해를 보호하기 위해 적용되는 PSC 슬래브에 부착된 내화패널의 성능을 평가할 목적으로 내화실험을 수행하였다. 연구방법: 내화실험은 RWS 화재 이력곡선 화재시간-온도곡선을 적용하였으며, 한국건설기술연구원(KICT)의 가열로를 이용하여 내화 성능을 평가하였다. 연구결과:국제터널학회(2004)에서 제시하는 기준으로 내화성능 실험을 실시한 결과, 내화패널과 콘크리트의 접촉면에서의 최대온도는 콘크리트에 손상을 주는 한계온도(380℃) 이하였으며, 접촉면과 25mm 이격된 지점에서의 최대온도는 철근에 손상을 주는 한계온도(250℃) 이하로 측정되었다. 실험결과로부터, 내화패널이 30mm두께로 부착된 PSC 슬래브 시험체는 내화성능을 가진 것으로 평가되었다. 결론: 터널이나 지하차도에서의 화재발생시 내화패널을 부착하는 보강방법은 화재로부터 구조물을 보호할 수 있으며 향후, 내화패널이 부착된 슬래브의 정적 성능시험을 수행하고, Pull-off test와 피로실험을 실시하여 내화패널의 부착성능을 확인하는 것이 필요하다.

• 한국지리정보학회지
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• 제11권3호
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• pp.80-91
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• 2008

UIS사업의 결과로 나온 공간데이터의 경우 막대한 비용투자에 비하여 활용의 정도는 기대에 미치지 못하고 있으며 공간데이터의 활용확대를 위하여 데이터의 효율적 관리 및 공유체계의 확립을 위한 노력은 반드시 필요하다. 본 연구는 지방자치단체내에서 공간 데이터의 효율적인 관리 및 공유체계확립과 공간데이터의 활용 확대를 위하여 사회연결망 분석 및 계획행동이론을 적용하였으며 부산광역시 공간데이터 사용 공무원을 대상으로 분석결과 공간데이터의 공유에 영향을 미치는 장애요인에는 데이터 사용자들간의 태도 및 주변과의 관계에서 발생하는 비기술적 장애요인의 비중이 높게 나타났다. 또한 데이터의 제공위치에 따라 공간데이터 공유의 장애요인에 대하여 다르게 인식하고 있는 것으로 나타났으며 이러한 사회적 신념이 행동의도에 영향을 미쳐서 또 다른 비기술적 장애요인이 발생하였다. 본 연구는 공간데이터의 활용확대를 위하여 인간의 행동예측을 위한 계획행동이론의 적용 및 공간데이터의 흐름을 파악하기 위한 사회연결망분석을 실시하여 부서에 속한 담당자들의 인식 및 공유장애요인을 규명하고 데이터 활용 확대로 접근할 수 있는 윤곽을 제시하였다.