• 한국자동차공학회논문집
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• 제16권5호
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• pp.37-43
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• 2008

The durability test of turbo-blower for PEM fuel cell is very important process of BOP development. It is a major barrier to the commercialization of these systems for stationary and transportation power applications. Commercial viability depends on improving the durability of the air supply system to increase the reliability and to reduce the lifetime cost. In this study, turbo-blower supported by oil-free bearing is introduced as the air supply system used by 80kW proton exchange membrane fuel systems. The turbo-blower is a turbo machine which operates at high speed, so air foil bearings suit their purpose as bearing elements. The impeller of blower was adopted mixed type of centrifugal and axial. So, it has several advantages for variable operating condition. The turbo-blower test results show maximum parasitic power levels below 1.67kW with the 30,000 rpm rotating speed, the flow rate of air has maximum 163SCFM(@PR1.1). For proper application of FCV, these have to durability test. This paper describes the experiment for confirming endurance and stability of the turbo-blower for 500 hours.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4228-4247
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• 2018

Many methods have been developed for the vehicles to create clusters in vehicular ad hoc networks (VANETs). Usually, nodes are vehicles in the VANETs, and they are dynamic in nature. Clusters of vehicles are made for making the communication between the network nodes. Cluster Heads (CHs) are selected in each cluster for managing the whole cluster. This CH maintains the communication in the same cluster and with outside the other cluster. The lifetime of the cluster should be longer for increasing the performance of the network. Meanwhile, lesser the CH's in the network also lead to efficient communication in the VANETs. In this paper, a novel algorithm for clustering which is based on the social behavior of Gray Wolf Optimization (GWO) for VANET named as Intelligent Clustering using Gray Wolf Optimization (ICGWO) is proposed. This clustering based algorithm provides the optimized solution for smooth and robust communication in the VANETs. The key parameters of proposed algorithm are grid size, load balance factor (LBF), the speed of the nodes, directions and transmission range. The ICGWO is compared with the well-known meta-heuristics, Multi-Objective Particle Swarm Optimization (MOPSO) and Comprehensive Learning Particle Swarm Optimization (CLPSO) for clustering in VANETs. Experiments are performed by varying the key parameters of the ICGWO, for measuring the effectiveness of the proposed algorithm. These parameters include grid sizes, transmission ranges, and a number of nodes. The effectiveness of the proposed algorithm is evaluated in terms of optimization of number of cluster with respect to transmission range, grid size and number of nodes. ICGWO selects the 10% of the nodes as CHs where as CLPSO and MOPSO selects the 13% and 14% respectively.

• 한국환경교육학회지:환경교육
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• 제15권2호
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• pp.1-13
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• 2002

The progress of environmental science and technology in the developed countries has been rapid in recent years. Particularly remarkable has been the advancement of various pollutant control measures, which have brought the pollution of inorganic factors such as air and water under control. In contrast, diversity of the ecosphere, of which man is a part, is being steadily impoverished and the biological community is getting unvaryingly uniform. These phenomena were brought about by the expansion of artificial environment such as new industrial complexes, transportation facilities and urban development. Man has constructed uniform and artificial environment, believing in the premise of confrontation with nature, to such a scale that the natural environment and biological community have lost their balance. This will increasingly endanger the soundness of the biotic environment of nature, which constitutes the potential foundation both for the survival environment of man as biological entity and for the development of human civilization. In order to guarantee the soundness of man's body, intelligence and sensitivity as wholesome gene pool on the earth and for the future of man, primarily important environmental education is the understanding of how man can everlasting exist in and with the survival environment. In view of this reality, it is vitally important to create ecologically diverse and well-balanced environment with living materials, i.e., vegetation in order to secure lasting survival environment for man. This task is urgently required in highly artificial environment where non-biological materials have forced the impoverishment of the biological community. Therefore, environmental education for the future should not be totally oriented to technology as that in the past nor it is limited to the medical aspect where well-being of human is the sole object of concern. That is to say, environmental education for the future should be one that provides knowledge that human can understand his place based on the ecological concept and thereby make him to have ethical consciousness that he can control his behavior within the reasonable level for ecological niche who he is located.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.750-753
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• 2017

최근 스마트폰, SNS, 사물인터넷이 확산되면서 생겨나는 빅데이타의 처리와 활용이 ICT 분야의 새로운 성장 동력으로 부상하고 있다. 하지만 이러한 빅데이터의 활용을 위해서는 개인정보 비식별화가 이루어져야한다. 비식별화는 개인의 데이터가 특정인과 연결되지 않도록 데이터 셋으로부터 식별정보를 제거하는 것으로 정보를 수집, 처리, 보관 혹은 배포하는데 있어 발생할 수 있는 개인정보노출의 위험을 줄이며 그 정보를 활용하고 공유하는데 그 목적을 두고 있다. 비식별화된 정보는 또한 재식별화되어 개인정보보호의 논란이 되고 있지만 빅데이터등의 개인정보가 비식별 처리되어 활용되는 사례는 점차 증가하고 있다. 또한 많은 비식별화 가이드라인의 등장과 함께 개인정보 비식별화 방법이 제시되고 있다. 따라서 본 연구에서는 빅데이타 비식별화 과정과 사후관리를 서술, 비식별화 방법을 비교분석하고 비식별화와 개인정보보호 관련 이슈와 해결과제를 제시한다.

• Spatial Information Research
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• 제12권2호
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• pp.211-228
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• 2004

본 연구는 대전시를 사례로 하여 주유소의 입지적 특성과 판매권역을 분석하기 위해 설문과 면접 조사, 그리고 GIS의 그리드 분석을 활용하였다. 주유소의 입지적 특성을 분석해 본 결과 고수익 입지유형은 인구밀도와 1일 통행량이 일정수준 이상으로 배후 상주인구와 통행인구가 많아 고수익이 예상되었고, 반면에 저수익 입지유형은 토지이용상 녹지와 개발제한구역 등으로 통행량도 낮아서 높은 수익을 기대하기 어려웠다. 대전시 인구수에 기반하여 판매권역의 공간분포 패턴을 살펴본 결과, 주유소 판매권역의 크기는 인구밀도가 조밀한 중심지역에서 인구밀도가 낮은 외곽지역으로 갈수록 확대되었다. 또한 인구수에 대비하여 주유소가 과다한 주유소 과밀지역과 과소 지역이 분포하는 불균형적 주유소 분포패턴을 보여주었다. 입지-배분모델을 적용한 결과 주유소 과밀 지역에서는 주유소의 수가 줄어들었고, 과소한 지역에서는 신규로 주유소가 입지하여 보다 균형적인 분포패턴을 보여주었다. 이와 같은 연구결과는 석유제품 유통기관별로 최소 배후지 규모를 만족시키면서 균형적 공간 분포패턴을 가질 수 있도록 배치하는데 필요한 기초적인 자료로 활용될 수 있을 것으로 예상된다.

• 융복합기술연구소 논문집
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• 제2권1호
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• pp.24-30
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• 2012

In this study, the trucks(2.9-liter) have been developed to use DME as fuel, and performance test of the vehicle's DME engine, power, emissions, fuel economy and vehicle aspects was conducted. For experiments, the fuel system(common-rail injectors and high-pressure pump included) and the engine control logic was developed, and ECU mapping was performed. As a result, the rail pressure from 40MPa to approximately 65% increase compared to the base injector has been confirmed that. Also, the pump discharge flow is 15.5 kg/h when the fuel rail pressure is 400rpm(40 MPa), and the pump discharge flow is 92.1 kg/h when the fuel rail pressure is 2,000rpm(40MPa). The maximum value of full-load torque capability is 25.5kgfm(based on 2,000rpm), and more than 90% compared to the level of the diesel engine were obtained. The DME vehicle was developed in this study, 120 km/h can drive to the stable, and calculated in accordance with the carbon-balance method of fuel consumptions is 5.7 km/L.

• 한국환경교육학회지:환경교육
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• 제15권1호
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• pp.137-147
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• 2002

The progress of environmental science and technology in the developed countries has been rapid in recent years. Particularly remarkable has been the advancement of various pollutant control measures, which have brought the pollution of inorganic factors such as air and water under control. In contrast, diversity of the ecosphere, of which man is a part, is being steadily Impoverished and the biological community is getting unvaryingly uniform. These phenomena were brought about by the expansion of artificial environment such as new industrial complexes, transportation facilities and urban development. Man has constructed uniform and artificial environment, believing in the premise of confrontation with nature, to such a scale that the natural environment and biological community have lost their balance. This will increasingly endanger the soundness of the biotic environment of nature, which constitutes the potential foundation both for the survival environment of man as biological entity and for the development of human civilization. In order to guarantee the soundness of man's body, intelligence and sensitivity as wholesome gene Pool on the earth and for the future of man, primarily important environmental education is the understanding of how man can everlasting exist in and with the survival environment. In view of this reality, it is vitally important to create ecologically diverse and well-balanced environment with living materials, i.e., vegetation in order to secure lasting survival environment for man. This task is urgently required in highly artificial environment where non-biological materials have forced the impoverishment of the biological community. Therefore, environmental education for the future should not be totally oriented to technology as that in the past nor it is limited to the medical aspect where well-being of human is the sole object of concern. That is to say, environmental education for the future should be one that provides knowledge that human can understand his place based on the ecological concept and thereby make him to have ethical consciousness that he can control his behavior within the reasonable level for ecological niche who he is located.

• Geomechanics and Engineering
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• 제16권6호
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• pp.643-654
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• 2018

Tunnel excavation leads to a disturbance on the initial stress balance of surrounding soils, which causes convergences around the tunnel and settlements at the ground surface. Considering the effective impact of settlements on the structures at the surface, it is necessary to estimate them, especially in urban areas. In the present study, ground settlements due to the excavation of East-West Line 7 of the Tehran Metro (EWL7) and the Abuzar tunnels are evaluated and the effect of the lateral earth pressure coefficient ($K_0$) on their extension is investigated. The excavation of the tunnels was performed by TBMs (Tunnel Boring Machines). The coefficient of lateral earth pressure ($K_0$) is one of the most important geotechnical parameters for tunnel design and is greatly influenced by the geological characteristics of the surrounding soil mass along the tunnel route. The real (in-situ) settlements of the ground surface were measured experimentally using leveling methods along the studied tunnels and the results were compared with evaluated settlements obtained from both semi-empirical and numerical methods (using the finite difference software FLAC3D). The comparisons permitted to show that the adopted numerical models can effectively be used to predict settlements induced by a tunnel excavation. Then a numerical parametric study was conducted to show the influence of the $K_0$ values on the ground settlements. Numerical investigations also showed that the shapes of settlement trough of the studied tunnels, in a transverse section, are not similar because of their different diameters and depths of the tunnels.

• 한국중재학회지:중재연구
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• 제29권2호
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• pp.35-63
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• 2019

Since imposing Performance Requirements (PRs) on investors have been conducted as a means to protect a host state's domestic industry in the short run, with its effect on improving the international balance of payments, it has been implemented mostly in developing countries. From the viewpoint of investors, however, PRs hinder free competition and investment activities and have the effect of distorting international trade activities; therefore, they are expected to bring detrimental effects on the host state's economic development in the long run. PRs provided by International Investment Agreements (IIAs) and WTO-TRIMs, too, included many abstract regulations which are grounded on the host state's economic efficiency in the past; however, those PRs are gradually being more concretely specified, shifting to a form of prohibition with the goals of increasing the protection on investors and realizing investment liberalization. Accordingly, when Korea freshly concludes IIAs or revises them afterwards, one should focus more on following the points regarding PRs. First, to protect Korean companies' investment activities, it is advantageous to list the contents of prohibited PRs extensively and concretely and create a stipulation. Second, it is necessary to list the contents of the PRs prohibited and add the phrases for prohibiting "any other similar requirements" explicitly, as well so as to cover the PRs that can appear newly. Third, as in the cases associated with PRs, issuable matters are mostly either the range of applying PRs or the conditions of applying them (relevance or detrimental effects); therefore, it is necessary to classify the cases accumulated by issues and analyze them thoroughly. In conclusion, as this study has analyzed the theoretical characteristics of PRs provided in IIAs and related cases and suggests exquisite theory regarding PRs, it not only lays fundamental grounds for follow-up research but also gives useful and practical guidelines for the parties concerned and the arbitrators according to the ISDS procedure.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.211-247
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• 2021

Livestock species experience several stresses, particularly weaning, transportation, overproduction, crowding, temperature, and diseases in their life. Heat stress (HS) is one of the most stressors, which is encountered in livestock production systems throughout the world, especially in the tropical regions and is likely to be intensified due to global rise in environmental temperature. The gut has emerged as one of the major target organs affected by HS. The alpha- and beta-diversity of gut microbiota composition are altered due to heat exposure to animals with greater colonization of pathogenic microbiota groups. HS also induces several changes in the gut including damages of microstructures of the mucosal epithelia, increased oxidative insults, reduced immunity, and increased permeability of the gut to toxins and pathogens. Vulnerability of the intestinal barrier integrity leads to invasion of pathogenic microbes and translocation of antigens to the blood circulations, which ultimately may cause systematic inflammations and immune responses. Moreover, digestion of nutrients in the guts may be impaired due to reduced enzymatic activity in the digesta, reduced surface areas for absorption and injury to the mucosal structure and altered expressions of the nutrient transport proteins and genes. The systematic hormonal changes due to HS along with alterations in immune and inflammatory responses often cause reduced feed intake and production performance in livestock and poultry. The altered microbiome likely orchestrates to the hosts for various relevant biological phenomena occurring in the body, but the exact mechanisms how functional communications occur between the microbiota and HS responses are yet to be elucidated. This review aims to discuss the effects of HS on microbiota composition, mucosal structure, oxidant-antioxidant balance mechanism, immunity, and barrier integrity in the gut, and production performance of farm animals along with the dietary ameliorations of HS. Also, this review attempts to explain the mechanisms how these biological responses are affected by HS.