• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.567-572
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• 2008

This paper's purpose is to improve determining of the critical response of curved bridge to multi-component seismic motion. There are several methods to combine responses by multi-component excitation response, 30%, 40% rules and square-root-of-sum (SRSS). These combination rules determine same value of critical response in straight bridges. However, each method has critical response value of different magnitude in curved bridges. Thus a study about critical response of curved bridges is required. This paper presents comparison critical responses value as each combination rule, 30%, 40% rules and SRSS on curved bridges with the different radiuses of curvature. This study was carried out by response spectrum analysis of OO IC steel box girder bridge using SAP2000. It is concluded as follows: 1) In curved bridges, 30% and 40% rules tend to underestimate the critical response relatively to SRSS. 2) When bridges have smaller radiuses than 100m, difference between SRSS and 30% or 40% rules let run errors up as radiuses of curvature decreased.

• Journal of Advanced Marine Engineering and Technology
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• 제12권3호
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• pp.57-67
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• 1988

Although handicapped by the inability to bridge the size gap between small laboratory sample and large engineering component, the V charpy test sample method does possess certain advantages, such as each of preparation, simplicity of test method, speed, low cost in test machinery, and low cost per test. On the other hand, the COD test method does posses advantages, which reduce the size gap between the laboratory sample and actual engineering component. Consequently, the correlation between V charpy absorbed energy and the critical COD value is required for estimating critical COD value from the simple V charpy test results. In this paper, the high tensile strength steel AH36 plate specimens having a single edge cracked notch were investigated to find out the correlation between V charpy absorbed energy and critical COD value in the welded parts under such various welding methods as shielded metal arc welding, the submerged arc welding and the electro gas welding by means of V charpy impact test and static 3-point bending test. Main results obtained are as follow ; 1. The relationships between V charpy absorbed energy Wc' and critical COD value ($\delta_c$)show; $\delta_c$=0.0065 Wc'+0.1906. 2. Ductile- brittle transition behaviours can be estimated by means of fracture appearance and general yielding behaviours. 3. The V charpy absorbed energy of SMAW is higher than that of SAW, EGW and similar relationships are obtained in the COD tests.

• 전기학회논문지P
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• 제58권1호
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• pp.27-32
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• 2009

A technical system generally comprise a number of subsystems and components that are interconnected in such a way that the system is able to perform a set of required function. Because of the complex system structure with serial, parallel and bridged connections, some certain subsystems or components are more critical than the others. The main concern of a reliability engineer is to identify potential failures and to prevent these failures from occurring. In order to prevent fatal failures, proper inspections and maintenance actions for each component are required Considering above objectives of reliability engineers and characteristics of a practical system, several practical method for evaluating system and component reliabilities have developed namely Birnbaum's and Fussell & Vesely's measures. However there are several critical weaknesses in traditional calculation process as the target system gets larger. In this paper, a new technique for calculating component's structural importance is proposed and compared to Birnbaum's with representative system examples (serial, parallel. k out of n, and bridge type).

• 한국자동차공학회논문집
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• 제13권6호
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• pp.56-62
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• 2005

The fatigue analysis and lifetime evaluation are very important in design procedure to assure the safety and reliability of the rubber components. Fatigue lifetime prediction methodology of the rubber component was proposed by incorporating the finite element analysis and fatigue damage parameter from fatigue test. Finite element analysis of 3D dumbbell specimen and rubber component were performed based on a hyper-elastic material model determined from material test. The Green-Lagrange strain at the critical location determined from the FEM was used for evaluating the fatigue damaged parameter of the natural rubber. Fatigue life of the rubber component are predicted by using the fatigue damage parameter at the critical location. Predicted fatigue lifes of the rubber component agreed fairly well the experimental fatigue lives.

• Earthquakes and Structures
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• 제15권5호
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• pp.453-462
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• 2018

Damages to buildings affected by a near-fault strong ground motion are largely attributed to the vertical component of the earthquake resulting in column failures, which could lead to disproportionate building catastrophic collapse in a progressive fashion. Recently, considerable interests are awakening to study effects of earthquake vertical components on structural responses. In this study, detailed modeling and time-history analyses of a 12-story code-conforming reinforced concrete moment frame building carrying the gravity loads, and exposed to once only the horizontal component of, and second time simultaneously the horizontal and vertical components of an ensemble of far-field and near-field earthquakes are conducted. Structural responses inclusive of tension, compression and its fluctuations in columns, the ratio of shear demand to capacity in columns and peak mid-span moment demand in beams are compared with and without the presence of the vertical component of earthquake records. The influences of the existence of earthquake vertical component in both exterior and interior spans are separately studied. Thereafter, the correlation between the increase of demands induced by the vertical component of the earthquake and the ratio of a set of earthquake record characteristic parameters is investigated. It is shown that uplift initiation and the magnitude of tensile forces developed in corner columns are relatively more critical. Presence of vertical component of earthquake leads to a drop in minimum compressive force and initiation of tension in columns. The magnitude of this reduction in the most critical case is recorded on average 84% under near-fault ground motions. Besides, the presence of earthquake vertical components increases the shear capacity required in columns, which is at most 31%. In the best case, a direct correlation of 95% between the increase of the maximum compressive force and the ratio of vertical to horizontal 'effective peak acceleration (EPA)' is observed.

• 대한조선학회논문집
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• 제55권3호
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• pp.274-280
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• 2018

This paper deals with the calculation of vulnerable areas of critical components required for the assessment of naval ship's vulnerability. Taking into account the effectiveness of threatening weapons, the probability density function of damage was used to assess vulnerable areas or vulnerabilities of critical components. It is shown that the vulnerable area of critical component can be simply computed from the damage function. Considering the weapon effectiveness of fragmentation and explosion on the target, both Carleton Damage Function and Rectangular Cookie Cutter Function representing the probability of damage are applied to the vulnerable area assessment. Carleton damage function is utilized to describe the weapon-target interaction in the vulnerability analyses. A problem of blast effect against an assumed naval ship is chosen as a case study. Vulnerability is evaluated by applying the suggested method to the equipments arranged in the engine room of the virtual ship.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.114-121
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• 2004

Frictional heating in brakes causes thermoelastic distortion of the contacting bodies and hence affects the contact pressure distribution. The resulting thermo-mechanical coupling can cause thermoelastic instability (TEI) if the sliding speed is sufficiently high, leading to non-uniform heating called hot spots and low frequency vibration known as hot judder. The vibration of brakes to the known phenomenon of frictionally-excited thermoelastic instability is estimated studying the interface temperature and pressure evolution with time. A simple model has been considered where a layer with half-thickness$\alpha$slides with speed V between two half-planes which are rigid and non-conducting. The advantage of this properlysimple model permits us to deduce analytically the critical conditions for the onset of instability, which is the relation between the critical speed and the growth rate of the interface temperature and pressure. Symmetrical component of pressure and temperature distribution at the layer interfaces can be more unstable than antisymmetrical component. As the thickness $\alpha$ reduces, the system becomes more apt to thermoelastic instability. For perturbations with wave number smaller than the critical$m_{cr}$ the temperature increases with m vice versa for perturbations with wave number larges than $m_{cr}$ , the temperature decreases with m.

• Tuberculosis and Respiratory Diseases
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• 제81권3호
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• pp.228-232
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• 2018

Background: Chronic bronchitis (CB) is an important phenotype in chronic obstructive pulmonary disease (COPD). The purpose of this study is to evaluate different pattern of COPD assessment test (CAT) score between CB and non-CB patients. Methods: Patients were recruited from 45 centers in Korea, as part of the Korean COPD Subgroup Study cohort. CB was defined when sputum continued for at least 3 months. Results: Total 958 patients with COPD were eligible for analysis. Among enrolled patients, 328 (34.2%) were compatible with CB. The CAT score was significantly higher in patients with CB than non-CB, and each component of CAT score showed a similar result. CB was significantly associated with CAT score when adjusted with age, sex, modified Medical Research Council, and post-bronchodilator forced expiratory volume in 1 second. Each component of CAT score between patients with CB and non-CB showed different pattern according to Global Initiative for Chronic Obstructive Lung Disease grade. Conclusion: CAT score is significantly higher in patients with CB than non-CB. Each component of CAT score was significantly different between two groups.

• 한국지역지리학회지
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• 제7권2호
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• pp.55-70
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• 2001

본 연구는 부산 신발산업 노동과정의 공간적 특성을 분석한 것이다. 신발산업의 생산체계는 제품 및 디자인 개발, 부품 및 소재 개발 생산, 완제품 조립 마케팅으로 구성되며, 생산과정별 노동과정의 성격도 상이하다. 전문적인 다기능 인력에 의존하는 제품 및 디자인 개발, 핵심 부품 및 소재 개발 생산, 마케팅 등의 핵심 기능은 자사상표의 제품생산 기업에서만 수행되며, 주로 선진국과 국내의 서울과 부산지역에 입지 한다. 중요 부품 및 소재 개발 생산의 준핵심 기능은 고기능 고숙련의 노동력을 요구하며 전통적인 신발생산지역에서 주로 이루어지고 있다. 또한 숙련 미숙련의 여성노동력에 대한 의존도가 높은 완제품 조립생산과정은 핵심 기능 흑은 준핵심 기능과 함께 이루어지거나 의무화되기도 한다. 공간적으로는 국내의 전통적인 신발생산지역을 중심으로 이루어지고 있으나 최근 후발 개발도상국으로 확대되고 있다. 반면에 남성 노동력에 대한 의존도가 높은 부품 및 소재의 개발 생산의 경우, 핵심 부품 및 소재는 선진국에서, 중요 부픔 및 소재는 부산의 완제품 생산업체나 혁신적인 부품 및 소재 생산업체에서, 그리고 표준화된 부품 및 소재의 생산은 주로 후발 개발도상국에서 이루어지고 있다.

• 한국디지털정책학회:학술대회논문집
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• 한국디지털정책학회 2004년도 International Conference on Digital Policy & Management
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• pp.299-310
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• 2004

Business process in e-government mostly embody as the flow of documents. Constructing a web-based document flow system becomes an critical task for today s digital government. But few of them use an off-the-shelf workflow product. Why? One of the reasons is that most of the workflow system are heavyweight, monolithic, and package a comprehensive set of features in an all-or-nothing manner. Another reason is that workflow technology lacks the constructs and modeling capability as programming language. It is incumbent on government IT organizations to transform their solution development to component-based computing model. Component technology isolates the computation and communication parts, but how to compose different software components is still a hard nut. An integrated development environment is necessary for CBSD. In this paper we propose a XML and component-based document flow-oriented integrated development environment (DFoIDE) for software developers. By writing some xml configure file, and operate on DFoIDE, developer can construct a workflow application quickly. This method divides system to several components and the activities in process are implemented as business component. Different components are discribed detailedly in this paper, especially one of the core component. Component Integrating Tool. Different perspectives in workflow application are seperated and depicted as different XML files. Correspondly, A component composition method for developing workflow application instead of workflow itself is proposed.