• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.33-43
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• 2019

Considerable efforts have been made to reduce greenhouse gas emission around the world to cope with climate change. The government is implementing G-SEED certification to promote energy efficient building design. This study aims to verify the effectiveness of the G-SEED certification system by analyzing the actual energy use of certified and non-certified office buildings. For this purpose, the energy consumption of 135 certified and 142 non-certified office buildings was analyzed according to the seasonal characteristics, building size and number of floors, approval year, and certification grade. The energy saving effects of certified buildings was about 50% higher than that of non-certified buildings. The seasonal energy consumption of buildings is closely related to the heating degree-days. The energy consumption of certified and non-certified buildings decreases with increasing approval year. On the other hand, the energy consumption according to building size and certification grade is not related. This study provides meaningful basic data of G-SEED certification system for future improvement. As the building energy performance standards are strengthened over the years, it is necessary to make the individual score of G-SEED certified projects open to the public to configure the factors of energy efficiency.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.153-158
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• 2007

사용자들의 특성에 맞게 개인화되고 세분화된 위치 기반 서비스를 제공하기 위해서는 방대한 이동 객체의 위치 이력 데이터 집합으로부터 유용한 패턴을 추출하여 의미 있는 지식을 탐사하기 위한 시공간 패턴 탐사가 필요하다. 현재까지 다양한 패턴 탐사 기법들이 제안되었으나 이동 패턴들 중 단순히 시공간 제약이 없는 빈발 패턴만을 추출하기 때문에 한정된 시간 범위와 제한적인 영역 범위 내에서의 빈발 패턴을 탐사하는 문제에는 적용하기 어렵다. 또한 패턴 탐사 수행 시 데이터베이스를 반복 스캔하여 탐사 수행시간이 많이 소요되는 문제를 포함하거나 메모리상에 탐사 대상인 후보 패턴 트리를 생성하는 방법을 통해 탐사 시간을 줄일 수는 있으나 이동 객체 수나 최소지지도 등에 따라 트리를 구성하고 유지하는데 드는 비용이 커질 수 있다. 따라서 이러한 문제를 해결하기 위한 효율적인 패턴 탐사 기법의 개발이 요구됨으로써 선행 작업으로 본 논문에서는 상세 수준의 객체 이력 데이터들의 시간 및 공간 속성을 의미 있는 시간영역과 공간영역 정보로 변환하는 시공간 데이터 일반화 방법을 제안한다. 제안된 방법은 공간 개념 계층에 대한 영역 정보들을 영역 Grid 해쉬 테이블(AGHT:Area Grid Hash Table)로 생성하여 공간 인덱스트리인 R*-Tree의 검색 방법을 이용해 이동 객체의 위치 속성을 2차원 공간영역으로 일반화하고, 시간 개념 계층을 생성하여 이동 객체의 시간적인 속성을 시간 영역으로 일반화함으로써 일반화된 데이터 집합을 형성하여 효율적인 이동 객체의 시간 패턴 마이닝을 유도할 수 있다.의 성능을 기대할 수 있을 것이다.onium sulfate첨가배지(添加培地)에서 가장 저조(低調)하였다. vitamin중(中)에서는 niacin과 thiamine첨가배지(添加培地)에서 근소(僅少)한 증가(增加)를 나타내었다.소시켜 항이뇨 및 Na 배설 감소를 초래하는 작용과, 둘째는 신경 경로를 통하지 않고, 아마도 humoral factor를 통하여 신세뇨관에서 Na 재흡수를 억제하는 작용이 복합적으로 나타내는 것을 알 수 있었다.으로 초래되는 복합적인 기전으로 추정되었다., 소형과와 기형과는 S-3에서 많이 나왔다. 이상 연구결과에서 입도분포가 1.2-5mm인 것이 바람직한 것으로 나타났다.omopolysaccharides로 확인되었다. EPS 생성량이 가장 좋은 Leu. kimchii GJ2의 평균 분자량은 360,606 Da이었으며, 나머지 두 균주에 대해서는 생성 EPS 형태와 점도의 차이로 미루어 보아 생성 EPS의 분자구조와 분자량이 서로 다른 것으로 판단하였다.TEX>개로 통계학적으로 유의한 차이가 없었다. Heat shock protein-70 (HSP70)과 neuronal nitric oxide synthase (nNOS)에 대한 면역조직화학검사에서 실험군 Cs2군의 신경세포가 대조군 12군에 비해 HSP70과 nNOS의 과발현을 보였으며, 이는 통계학적으로 유의한 차이를 보였다(p<0.05). nNOS와 HSP70의 발현은 강한 연관성을 보였고(상관계수 0.91, p=0.000), nNOS를 발현하는 세포가 동시에 HSP70도 발현함을 확인할 수 있었다. 결론: 우리는

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.6
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• pp.79-89
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• 2014

The purpose of this study is to draw the implication for building domestic housing-related co-operatives by understanding activities of housing-related co-operatives from case study and by suggesting the start-up typology for possible domestic housing-related co-operatives and requisites for building them. According to their activities housing-related co-operatives are categorized into three types which are housing supply and operation type, maintain and improve the existing housing type, and design and performance improvement type. National housing policy should be connected to housing co-operatives indirectly. That is, the policy direction ought to be not toward controlling housing co-operatives, letting them supply more houses directly, but toward supporting voluntary co-operatives, showing them the overall housing policy blueprint. Co-operatives cannot be a panacea. Too much protection or support for co-operatives could lead to a reverse discrimination against private companies, and the co-operatives might overuse this kind of prominent position. We need to focus on the possibility of the role of co-operatives as a facilitator for local economy rather than a perfect substitute for the existing economy system.

• Journal of Technology Innovation
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• v.23 no.3
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• pp.169-199
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• 2015

Information and communication technologies (ICT) have been combined with products from other industries to provide new functionality, as recently shown in the cases of Internet of Things (IoT). Modularity assumes a crucial role in such technological convergence, and has impacts on the relationship between organizations as well as competition within an industry. Interface standards, which ensure the connectivity between modules, serve as a critical factor in the process by which modularity affects organization systems and industry structure. To understand the aforementioned phenomenon, we studied modularity and interface standards with a focus on the interaction between technology and organization systems and subsequent changes in industrial dynamics. This paper examines previous literature on modularity and interface standards in the aspects of product architecture, organization systems, and institutional factors. With this analytical framework, we conducted a comparative analysis of electronic and automotive industries to derive implications for standardization policy. This research has shown the significance of external open interface standards in shaping an industrial landscape where a variety of module producers horizontally compete. It also advises that policymakers take into account product characteristics, engagement of leading firms in an industry, and institutional factors such as WTO law in the design of standardization policy.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.28-28
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• 2001

$Bi_2Te_3$계 열전반도체 재료는 200 ~ 400K 정도의 저온에서 에너지 변환 효율이 가장 높은 재료로서 열전냉각 및 발전재료로 제조볍 및 특성에 관한 많은 연구가 진행되어 왔다. 전자냉각 모듈의 제조에는 P형 및 N형 $Bi_2Te_3$계 단결정이 주로 사용되고 있으나. $Bi_2Te_3$ 단결정은 C축에 수직한 벽개면을 따라 균열이 쉽게 전파하기 때문에 소자 가공사 수윤 저하가 가장 큰 문제점으로 지적되고 있다. 이에 따라 최근 열전재료의 가공방법에 따른 회수율 증가 및 열전특성 향상에 관한 열간압출, 단조와 같은 연구가 활발히 이루어지고 있다. 본 연구는 가스분사법(gas atomizer)을 이용하여 용질원자 편석의 감소, 고용도의 증가,균일고용체 형성, 결정립미세화 둥 급속응고의 장점을 이용하여 화학적으로 균질한$Bi_2Te_3$계 열전재료 분말을 제조하고, 제조된 분발을 압출가공하여 기계적성질, 소자의 가공성 및 열전 성능 지수율 향상시키는데 연구 목적이 있다. 본 설험에서는 99.9%이상의 고순도 Bi. Te. Se. Sb를 이용하여, 고주파 유도로에서 Ar 분위기로 용융하고, 가스분사법를 이용하여 균질한 $Bi_2Te_3$계 열전재료 분만을 제조하였다. 분말표면의 산화막을 제거하기 위하여 수소분위기에서 환원처리를 행하였고, 된 분말을 Al 캔 주입하여 냉간성형 한 후 진공중에서 압출온도를 변화시켜 열간압출 가공을 행하였다. 압출 온도변화에 따른 압출재의 미세조직 및 열전특성에 중요한 영향을 미치는 C면 배향에 대한 결정방위 해석, 압출재의 압축강도 등을 분석하였으며, 압출온도에 따삼 미세조직 변화와 결정방위의 변화에 따른 열전특성의 관계를 해석하였다성시켰고 이들이 산인 HNO3에서 녹았기 때문이다. 본 연구에서 개발된 새로운 에칭 용액인 90H2O2 - 10HNO3 (vol%)의 에칭 원리가 똑같이 적용 가능한 다른 종류의 초경 합금에서도 사용이 가능할 것으로 판단된다.로 판단된다.멸과정은 다음과 같다. 출발물질인 123 분말이 211과 액상으로 분해될 때 산소가스가 배출되며, 이로 인해 액상에서 구형의 기공이 생성된다. 이들 중 일부는 액상으로 채워져 소멸되나, 나머지는 그대로 남는다. 특히, 시편 중앙에 서는 수십-수백 마이크론 크기의 커다란 기공이 다수 관찰된는데, 이는 기공의 합체로 만들어진 것이다. 포정반응 열처리 시 기공 소멸로 만들어진 액상포켓들은 주변 211 입자와 반응하여 123 영역으로 변한다. 이곳은 다른 지역과 비교하여 211 밀도 가 낮기 때문에, 미반응 액상이 남거나 211 밀도가 낮은 123 영역이 된다. 액상으로 채워지지 못한 구형의 기공들 중 다수가 123 결정 내로 포획되며, 그 형상은 액상/ 기공/고상 계면에너지에 의해 결정된다.단의 경우, 파단면이 매끄럽고 파변상의 결정립도 매우 미세하였으며, 산확물 의 용집도 찾아보기 어려웠 나, 접합부 파단의 경우에는 파변의 굴곡이 비교척 심하고 연성 입계파괴의 형태를 보였￡며, 결정립도 모채부 파단의 경우에 비해 조대하였다. 조대하였다. 셋째, 주상기간 중 총 에너지 유입률 지수와 $Dst_{min}$ 사이에 높은 상관관계가 확인되었다. 특히 환전류를 구성하는 주요 입자의 에너지 영역(75~l13keV)에서 가장 높은(0.80) 상관계수를 기록했다. 넷째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의

• Journal of Energy Engineering
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• v.22 no.2
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• pp.96-104
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• 2013

Coal gasification is considered as one of the best alternatives among clean coal technology and new concept next generation technologies are under being developed to achieve low cost as well as high efficiency. In this study we have developed double swirl multi-burner as part of the development of low cost compact gasifier. We installed new concept multi-burner with pulverized coal distributor to the body of existing gasifier for burner test. Gasification test was performed under the condition of $6.4{\sim}7.2kg/cm^2$ and $1170{\sim}1300^{\circ}C$ by using Indonesian ABK (sub-bituminous) coal to get operation condition of new concept multi-burner. Our interest was focused to ensure a stable operating condition rather than the gasifier performance evaluation. As a result, we were able to achieve the carbon conversion of 84% and the cold gas efficiency of 52.1% at the stable operating conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.619-626
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• 2020

The development of new antifreeze mixtures containing non-amine-type corrosion inhibitors, which considers environmental protection, has become a major issue. In this study, four non-amine-type corrosion inhibitors were synthesized and used to produce five kinds of new antifreeze for automobiles to evaluate the rate of copper corrosion. The effects were evaluated by the weight change, surface observation, roughness measurement, and measurement of copper elution in the solution. The amount of copper eluted measured by ICP from Sample 4 was small, and the elution rate was prolonged. Sample 4 showed the best anti-corrosion performance owing to a corrosion suppression effect by passivating copper because the metal surface was smooth after the test, and the corrosion product layer was formed evenly on the surface as small local corrosion was observed. The major corrosion inhibitor added to Sample 4 was 1-aminomethyl(N',N'-di(2-hydroxyethyl)benzotrazole, which contained a certain amount in Sample 5 to show relatively high local corrosion but passivation in progress. Therefore, among the four corrosion inhibitors, 1-aminomethyl(N',N'-di(2-hydroxyethyl)benzotrazole had the highest corrosion inhibitory effect. This corrosion inhibitor prevents corrosion by promoting the passivation of copper on the antifreeze.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.242-248
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• 2016

The overall reaction rate of fuel cell is governed by oxygen reduction reaction (ORR) in the cathode due to its slowest reaction compared to the oxidation of hydrogen in the anode. The ORR efficiency can be readily evaluated by examining the adsorption strength of atomic oxygen on the surface of catalysts (i.e., known as a descriptor) and the adsorption energy can be controlled by transforming the surface geometry of catalysts. In the current study, the effect of the surface geometry of catalysts (i.e., strain effect) on the adsorption strength of atomic oxygen on platinum catalysts was analyzed by using density functional theory (DFT). The optimized lattice constant of Pt ($3.977{\AA}$) was increased and decreased by 1% to apply tensile and compressive strain to the Pt surface. Then the oxygen adsorption strengths on the modified Pt surfaces were compared and the electron charge density of the O-adsorbed Pt surfaces was analyzed. As the interatomic distance increased, the oxygen adsorption strength became stronger and the d-band center of the Pt surface atoms was shifted toward the Fermi level, implying that anti-bonding orbitals were shifted to the conduction band from the valence band (i.e., the anti-bonding between O and Pt was less likely formed). Consequently, enhanced ORR efficiency may be expected if the surface Pt-Pt distance can be reduced by approximately 2~4% compared to the pure Pt owing to the moderately controlled oxygen binding strength for improved ORR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.608-616
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• 2018

If a general nonlinear system is linearized by the successive multiplication of the 1st and 2nd order systems, then there are four types of poles in this linearized system: the pole of the 1st order system and the equal poles, two distinct real poles, and complex conjugate pair of poles of the 2nd order system. Linear Quadratic (LQ) control is a method of designing a control law that minimizes the quadratic performance index. It has the advantage of ensuring the stability of the system and the pole placement of the root of the system by weighted matrix adjustment. LQ control by the weighted matrix can move the position of the pole of the system arbitrarily, but it is difficult to set the weighting matrix by the trial and error method. This problem can be solved using the characteristic equations of the Hamiltonian system, and if the control weighting matrix is a symmetric matrix of constants, it is possible to move several poles of the system to the desired closed loop poles by applying the control law repeatedly. The paper presents a method of calculating the state weighting matrix and the control law for moving the equal poles with Jordan blocks to two real poles using the characteristic equation of the Hamiltonian system. We express this characteristic equation with a state weighting matrix by means of a trigonometric function, and we derive the relation function (${\rho},\;{\theta}$) between the equal poles and the state weighting matrix under the condition that the two real poles are the roots of the characteristic equation. Then, we obtain the moving-range of the two real poles under the condition that the state weighting matrix becomes a positive semi-finite matrix. We calculate the state weighting matrix and the control law by substituting the two real roots selected in the moving-range into the relational function. As an example, we apply the proposed method to a simple example 3rd order system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.77-83
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• 2020

4WD technology is being actively applied to passenger cars. Therefore, dry multi-plate clutches are used for transfer cases. On the other hand, dry clutches have problems related to large vibrations and poor ride quality. To solve this problem, this paper proposes a multi-plate clutch with an MR fluid. When fastening the multi-plate clutch in the transfer case, the proposed MR clutch was applied to reduce the shock and friction, which is a key component in a four-wheel-drive system. MR multi-plate clutch has a fluid coupling mode and a compression mode. A torque model equation was derived for the optimal design. The analysis was performed using Ansys Maxwell to optimize the design parameters of the multi-plate clutch. Electromagnetic field analysis confirmed the strength of the magnetic field when the number of disks and plates were changed, and the maximum strength of the magnetic field was 0.45 Tesla. By applying this to the torque equation, the spacing between the plates was 2 mm, and the inner and outer diameters of the plates were selected to be 45 mm and 55 mm, respectively. Overall, this paper proposes an optimal design technique to maximize the performance of an MR multi-plate clutch.