• 대한교통학회지
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• 제27권3호
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• pp.49-58
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• 2009

대전시를 사례로 위계수준을 달리한 4개의 노선망 대안(대안 1은 위계가 없는 노선망, 대안 2, 대안 3, 대안 4는 각각 초급, 중급, 상급 수준의 위계를 가진 노선망)을 작성하고, 평가지표(차내통행시간비용, 대기시간비용, 환승페널티비용)를 산출하여 대안간 비교를 통해 효율성을 분석하였다. 차내통행시간비용은 위계가 높은 대안일수록 감소하다가 위계가 매우 높아지면 다시 증가하는 것으로나타났다. 대기시간 비용은 위계가 높은 대안일수록 큰폭으로 감소하며, 환승페널티비용은 위계가 높은 대안일수록 증가하는 것으로 나타났다. 종합적으로 볼 때 총통행비용은 위계가 있는 노선망이 위계가 없는 노선망에 비하여 낮은 것으로 나타나 위계구조를 가진 노선망의 효율성이 높은 것으로 나타났다. 위계가 있는 노선망 중에서는 위계가 높을수록 총통행비용이 감소하다가 위계가 지나치게 높아지게 되면 오히려 증가하는 특성을 보임으로써 중급수준의 위계를 가진 노선망이 가장 효율성이 높은 것으로 분석되었다.

• 전기전자학회논문지
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• 제18권2호
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• pp.248-254
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• 2014

계층 회의는 회의에 참가한 단말기 간 교환되는 데이터가 계층 구조로 전달되기 때문에 정보 지연이 발생되게 된다. 본 논문에서, 단말기 사이의 평균 경로 거리를 최소화하고 단말기의 컴퓨터 자원을 고려하여 비점진적 계층 회의를 구성하는 새로운 방법을 제안하고자 한다. 참가를 원하는 단말기들을 현재 구성중인 계층 회의에 포함 시키고자 할 때, 제안한 알고리즘은 회의 내에서 컴퓨터 자원을 고려하여 참가한 단말기들을 가운데 연결 가능한 단말기들을 선택한다. 그 다음, 참가를 원하는 단말기들과 선택 단말기들 간의 거리를 계산하고 거리가 최소가 되는 단말기 쌍을 선택한 뒤, 이 단말기 쌍을 연결하여 계층 회의를 확장한다. 이러한 방법은 모든 단말기 들이 회의에 포함될 때까지 반복된다. 제안한 방법을 이용하여 모의실험 한 결과 비점진적 계층 회의 방법이 단말기 간의 평균 경로 거리 관점에서 점진적 계층회의 방법보다 24% 효율적으로 구성될 수 있음을 알 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.422-429
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• 2001

A two dimensional hierarchical elements are investigated for a use on the incompressible flow computation. The construction of hierarchical elements are explained through the tensor product of 1-D hierarchical functions, and a systematic treatment of essential boundary values has been developed for the degrees of freedom corresponding to higher order terms. The numerical study for the poisson problem showed that the present scheme can increase the convergence and accuracy of finite element solutions, and can be more efficient than the standard first order with many elements. Also, for Stokes and cavity flow cases, solutions from hierarchical elements showed better resolutions and future promises for higher order solutions.

• 한국전산유체공학회지
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• 제9권3호
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• pp.57-65
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• 2004

The incompressible Navier-Stokes equations in two dimensions are stabilized by a modified residual method, and then discretized by hierarchical elements. The stabilization is necessary to escape from the Ladyzhenskaya-Babuska-Brezzi(LBB) constraint and hence to achieve an equal order formulation. To expedite a standard iterative method such as the conjugate gradient squared(CGS) method, a preconditioning technique called the Hierarchical Iterative Procedure(HIP) has been applied. In this paper, we increased the order of interpolation within an element up to cubic. The hierarchical elements have been used to achieve a higher order accuracy in fluid flow analyses, but a proper efficient iterative procedure for higher order finite element formulation has not been available so far The numerical results by the present HIP for the lid driven cavity flow and others showed the present procedure to be stable, very efficient and useful in flow analyses in conjunction with hierarchical elements.

• 대한인간공학회지
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• 제22권4호
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• pp.59-78
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• 2003

Most regression models of anthropometric variables use stature and/or weight as regressors; however, these 'flat' regression models result in large errors for anthropometric variables having low correlations with the regressors. To develop more accurate regression models for anthropometric variables, this study proposed a method to estimate anthropometric variables in a hierarchical manner based on the relationships among the variables and a process to develop and improve corresponding regression models. By applying the proposed approach, a hierarchical estimation structure was constructed for 59 anthropometric variables selected for the occupant package design of a passenger car and corresponding regression models were developed with the 1988 US Army anthropometric survey data. The hierarchical regression models were compared with the corresponding flat regression models in terms of accuracy. As results, the standard errors of the hierarchical regression models decreased by 28% (4.3mm) on average compared with those of the flat models.

• 한국시뮬레이션학회논문지
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• 제8권4호
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• pp.89-107
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• 1999

There are many issues in computer simulation such as verifying model code, validating models, understanding the dynamics of systems and training the personnel. The developers of simulation tool have been interested in the animation since it can help solve the problems related to the above listed issues. In practice, animation is one of the popular method for displaying the simulation output for solving these problems. Trying to display all the graphic objects representing the dynamics of the models being simulated, however, causes the distraction of focus, which results in solving the above listed problems difficult. The redundant graphic objects also Increase the computer computation overhead. This paper presents a hierarchical animation environment in which the users can have better focus on the dynamics of system components. In hierarchical animation environment the users can observe the dynamics of system by selectively choosing the hierarchical level and components with in a level of the hierarchically structured model. Especially when the model is large and complex the selection of observation level is needed. The design approach of the hierarchical animator is based on the DEVS(Discrete Event system Specification) formalism which is theoretically well grounded means of expressing modular and hierarchical models.

• 음성과학
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• 제8권4호
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• pp.75-86
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• 2001

This study explored the effectiveness of a hierarchical treatment of aphasic perseveration (TAP) program in a Korean client with transcortical sensory aphasia. The subject with 52% perserveration score (Korean version of Boston Naming Test : K-BNT) was 44 year-old female with MCA (Middle cerebral artery) infarction. The experimental design used was an alternating treatment design with the hierarchical TAP and conventional audio-visual stimulation. The frequency of occurrence of perseverative behaviors and correct response in naming performance were analyzed and compared. It was claimed that the hierarchical TAP was more effective in naming performance than conventional audio-visual stimulation in terms of correct naming response. The frequency of occurrence of perseverative behaviors was lower in hierarchical TAP but the difference was relatively small. Unlike in English, sentence completion task was no longer stimulable while unison speech was very stimulable among the specific strategies of TAP program in Korean. Therefore, it could be said that TAP is language-dependent.

• Journal of International Society for Simulation Surgery
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• 제3권1호
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• pp.9-11
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• 2016

Purpose In this paper we proposed bi-directional hierarchical regression for accurate human finger landmark detection with only using depth information.Materials and Methods Our algorithm consisted of two different step, initialization and landmark estimation. To detect initial landmark, we used difference of random pixel pair as the feature descriptor. After initialization, 16 landmarks were estimated using cascaded regression methods. To improve accuracy and stability, we proposed bi-directional hierarchical structure.Results In our experiments, the ICVL database were used for evaluation. According to our experimental results, accuracy and stability increased when applying bi-directional hierarchical regression more than typical method on the test set. Especially, errors of each finger tips of hierarchical case significantly decreased more than other methods.Conclusion Our results proved that our proposed method improved accuracy and stability and also could be applied to a large range of applications such as augmented reality and simulation surgery.

• 한국건축시공학회지
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• 제14권2호
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• pp.177-186
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• 2014

The gang-form widely used in apartment construction sites has advantages compared to scaffolding in preventing falling accidents. One problem, however, is that safety accidents associated with gang-form works repeatedly occur due to worker carelessness. In this study, hierarchical checking tables are provided to support safety management activities for the gang-form works at the sites. Through a survey of experts and analyses of case studies of construction accidents, 137 safety check items are classified by participant type based on a hierarchical safety check scheme. The applicability and effectiveness of the hierarchical checking tables was evaluated through interviews with experts. It was found that the hierarchical checking tables enabled each gang-form related participant to check his own safety management items, and provided a level-wise structure to site safety management systems.

• 정보보호학회논문지
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• 제13권3호
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• pp.129-134
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• 2003

C. Gentry와 A. Silverberg의 Hierarchical ID-based cryptograph $y^{［3］}$서는 계층에서 수신자의 단계가 깊어짐에 따라 암호문의 길이가 선형적으로 증가한다는 문제가 있었다. 본 논문에서는 HIDS(Hierarchical m-based Signature)의 서명값을 활용해 암호문의 길이를 줄이는 새로운 방법을 제안한다.