• Computers and Concrete
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• 제21권5호
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• pp.593-605
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• 2018

A nonlinear finite element modeling approach is developed to assess the behavior of a dowel bar embedded on a single concrete block substrate, subjected to monotonic loading. In this approach, a discrete representation of the steel reinforcing bar is considered, using beam finite elements with nonlinear material behavior. The bar is connected to the concrete embedment through nonlinear Winkler spring elements. This modeling approach can only be used if a new constitutive model is developed for the spring elements, to simulate the deformability and strength of the concrete substrate. To define this constitutive model, an extensive literature review was conducted, as well as 3 experimental tests, in order to select the experimental data which can be used in the calibration of the model. Based on this data, an empirical model was established to predict the global dowel response, for a wide range of bar diameters and concrete strengths. This empirical model provided the information needed for calibration of the nonlinear Winkler spring model, valid for dowel displacements up to 4 mm. This new constitutive model is composed by 5 stages, in order to reproduce the concrete substrate response.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.2072-2078
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• 2012

본 논문은 직무분석에 대한 제 이론을 상황론적 관점으로 접근함으로써 각기 다른 특징을 가진 직무분석 기법을 통합할 수 있는 가능성을 모색하였다. 상황론적 관점에서는 최상의 방법이 한 개만 있는 것이 아니라 다양하게 공존할 수 있다고 보기 때문에, 직무분석의 대표적인 기법(작업중심 vs. 사람중심)을 양자택일이 아닌 통합적 접근으로 시도하였다. 그 결과, 직무특수적인 정보가 필요한 상황에서는 작업분석기법을 사용하고, 우수인재의 노하우가 필요한 상황에서는 사람중심 분석기법을 사용하여 두 가지 기법의 장점을 모두 살릴 수 있는 통합적 직무분석 프로세스를 설계하였다. 통합형 직무분석기법이 실제로 어떻게 적용될 수 있는지를 구체적으로 보여주기 위해 국가직업능력표준개발사례를 분석하여 이론적 실무적 시사점과 함께 제시하였다.

• Structural Engineering and Mechanics
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• 제26권3호
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• pp.315-341
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• 2007

A sudden change of stiffness in a structure, associated with the events such as weld fracture and brace breakage, will cause a discontinuity in acceleration response time histories recorded in the vicinity of damage location at damage time instant. A new damage index is proposed and implemented in this paper to detect the damage time instant, location, and severity of a structure due to a sudden change of structural stiffness. The proposed damage index is suitable for online structural health monitoring applications. It can also be used in conjunction with the empirical mode decomposition (EMD) for damage detection without using the intermittency check. Numerical simulation using a five-story shear building under different types of excitation is executed to assess the effectiveness and reliability of the proposed damage index and damage detection approach for the building at different damage levels. The sensitivity of the damage index to the intensity and frequency range of measurement noise is also examined. The results from this study demonstrate that the damage index and damage detection approach proposed can accurately identify the damage time instant and location in the building due to a sudden loss of stiffness if measurement noise is below a certain level. The relation between the damage severity and the proposed damage index is linear. The wavelet-transform (WT) and the EMD with intermittency check are also applied to the same building for the comparison of detection efficiency between the proposed approach, the WT and the EMD.

• 자원ㆍ환경경제연구
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• 제11권1호
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• pp.99-119
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• 2002

As an alternative to classical maximum likelihood approach for analyzing dichotomous choice contingent valuation (DCCV) data, this paper develops a Bayesian approach. By using the idea of Gibbs sampling and data augmentation, the approach enables one to perform exact inference for DCCV models. A by-product from the approach is welfare measure, such as the mean willingness to pay, and its confidence interval, which can be used for policy analysis. The efficacy of the approach relative to the classical approach is discussed in the context of empirical DCCV studies. It is concluded that there appears to be considerable scope for the use of the Bayesian analysis in dealing with DCCV data.

• 한국조경학회지
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• 제27권4호
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• pp.108-121
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• 1999

Creative spatial production in Environmental design relies, in large part, on the artistic talent of the designer(s) that is applied to the design solutions or schematic plans. This study proposes the importance and necessity of the use of 'Plastic Arts" or the technique of artistic manipulation and definition of space in Environmental Design studio programs. This fundamental design approach is currently lacking in Korean design studio programs. Moreover, the current trend of interdisciplinary design (that is, between landscape architecture, architecture, urban and environmental planning) emphasizes the importance of such techniques. "plastic Arts" techniques can serve as a basic code of communication between design disciplines and can in itself be a common approach. The method of this study is based on the empirical datas, that is, the educational performances which are executed in Landscape studio programs of some Korean Universities. The results are summarized as follows; 1. The program, "Plastic Arts" Should be included in the basic organization of Landscape design studio programs. 2. Unlike France where "Plastic Arts" program is implemented through out Landscape Architecture programs in Korea, "Plastic Arts" should be intensified and continued for longer period of time for students in the initial years. 3. In creation of "Plastic Arts" programs for Korean Landscape Design studios, the traditional and contemporary values of aesthetic of the Nature should be taken in consideration. 4. In order to confirm the necessity of "Plastic arts" program in the organization of landscape curriculum, more studies should be done, with empirical datas.pe curriculum, more studies should be done, with empirical datas.

• 한국조사연구학회:학술대회논문집
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• 한국조사연구학회 2001년도 춘계학술논문발표대회 발표논문집
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• pp.45-56
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• 2001

복합표본조사 데이터 분석에서 회귀모형 접근법은 크게 표본설계 기반 접근법(design-based approach)과 일반화 추정 방정식 접근법(generalized estimating equations approach)으로 구분된다. 본 논문은 이들 접근법과 모형기반 접근법을 비교하여 설명하고, 각 접근법에서 표본설계가 모수 추정에 미치는 영향을 설계 효과와 가중치 효과 분석을 통해서 살펴보았다.

• 산업경영시스템학회지
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• 제28권4호
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• pp.124-133
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• 2005

The purpose of this study is to analyze the effectiveness of process approach for business performance of a company certified with ISO 9000 : 2000 quality management system. The result of this empirical research were identified as follows. Documentation and an intelligence process appeared with a preference matter in an influence to reach to a business performance of a company through the organization which established a process approach. It reveals that the process approach of quality management system might affect positively for customer satisfaction, product qualify, financial results and cost reduction.

• 한국항만경제학회지
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• 제19권2호
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• pp.33-53
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• 2003

The purpose of this paper is to investigate the effectiveness of port investemnt which is one of the important elements for measuring the port efficiency by using congestion approach of DEA(Data Envelopment Analysis). Congestion is said to be present when increases in inputs result in input reductions. Congestion approach takes the forms of weak input disposability and strong input disposability. Empirical analysis by using congestion approach in this paper identified inefficiencies in the inputs including port investment, and indicated inefficient ports like the ports of Sokcho, Gunsan, Pohang, and Seoguipo which shows the large amount of slacks with congestion especially in terms of port investment. Therefore these ports should examine the reason about the inefficiency of port investment. The main policy implication based on the findings of this study is that The Ministry of Maritime Affairs & fisheries in Korea should introduce congestion approach when the amount of port investment to each port is decided.

• Structural Engineering and Mechanics
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• 제14권1호
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• pp.57-70
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• 2002

This work presents an iterative mesh partitioning approach to improve the efficiency of parallel substructure finite element computations. The proposed approach employs an iterative strategy with a set of empirical rules derived from the results of numerical experiments on a number of different finite element meshes. The proposed approach also utilizes state-of-the-art partitioning techniques in its iterative partitioning kernel, a cost function to estimate the computational cost of each submesh, and a mechanism that adjusts element weights to redistribute elements among submeshes during iterative partitioning to partition a mesh into submeshes (or substructures) with balanced computational workloads. In addition, actual parallel finite element structural analyses on several test examples are presented to demonstrate the effectiveness of the approach proposed herein. The results show that the proposed approach can effectively improve the efficiency of parallel substructure finite element computations.

• 한국항만경제학회:학술대회논문집
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• 한국항만경제학회 2003년도 정기학술대회지
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• pp.221-242
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• 2003

The purpose of this paper is to investigate the effectiveness of port investment which is one of the important elements for measuring the port efficiency by using congestion approach of DEA(Data Envelopment Analysis). Congestion is said to be present when increases in inputs result in ouput reductions. Congestion approach takes the forms of weak input disposability and strong input disposability. Empirical analysis by using congestion approach in this paper identified inefficiencies in the inputs including port investment, and indicated inefficient ports like the ports of Sokcho, Gunsan, Pohang, and Seoguipo which shows the large amount of slacks with congestion especially in terms of port investment. Therefore these ports should examine the reason about the inefficiency of port investment. The main policy implication based on the findings of this study is that The Ministry of Maritime Affairs & Fisheries in Korea should introduce congestion approach when the amount of port investment to each port is decided.