• 한국정밀공학회지
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• 제15권7호
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• pp.98-103
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• 1998

Recently, DVD/CD compatible driver is needed for DVD and CD is widely used as a new optical data restoring device. The optical systems of DVD and CD driver are different because they have different optical feature. If only one objective lens is used, the change of an aperture or a dual focal length of the lens is required. This method, however, increases the number of parts and results in loss of the power of laser light. Hence, we propose a dual lens actuator design that can read DVD and CD respectively. Albeit magnetic spring is important mechanism in the dual lens actuator design, there has not been the systematic approach to design the mechanism in the preceding researches. In this article. the guideway to design magnetic spring is presented by using the qualitative theoretical approach and the finite element analysis.

• 한국산학기술학회논문지
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• 제19권5호
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• pp.650-660
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• 2018

접속슬래브는 교량의 접속부의 주행성에 중요한 역할을 수행한다. 하지만, 고속도로 교량의 접속슬래브는 길이의 70%를 지간으로 하는 단순보로 설계하고 부재력만 산정하고 있다. 따라서, 접속슬래브의 거동과 지지점의 침하로 인한 영향을 고려하지 못한다. 본 연구에서는 토압분리형 교량의 접속슬래브에 대해 비지지길이와 지반 침하에 따른 거동을 평가하였다. 이 교량은 보강토옹벽으로 횡방향토압을 지지하므로 접속슬래브가 지면에 지지되지 않는 비지지구간이 발생되고 지지되는 지반에서도 침하가 발생될 수 있다. 이를 검토하기 위해, 접속슬래브의 길이에 따라, 토압분리형 교량 설계지침 (2016)에 제시된 접속슬래브 길이의 70%를 지간으로 하는 단순보로 설계하여, 단면력을 산정하였다. 그리고 비지지길이와 지반 침하에 따른 거동을 규명하기 위한 구조해석 모델을 생성하였다. 구조해석 결과, 비지지길이가 증가되면 휨모멘트는 감소되었고 침하량이 증가되면 휨모멘트는 증가되었다. 그리고 설계 단면력이 구조해석보다는 크게 산정되었으며, 설계지침에 따라 접속 슬래브를 설계하면, 안정성에는 문제가 없는 것으로 나타났다. 하지만, 수직변위는 비지지길이에 관계없이 침하량이 10mm 이상이 되면, 유지관리기준인 1/200 곡선을 넘어서는 것으로 나타났다. 토압분리형 교량의 접속슬래브는 비지지길이에는 큰 영향을 받지 않지만, 지반 침하에는 큰 영향을 받았다. 따라서, 접속슬래브를 지지하는 보강토옹벽에 과도한 침하가 발생되며, 설계 휨모멘트를 초과할 수 있으므로 이에 대한 엄격한 관리가 필요하다.

• Geomechanics and Engineering
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• 제11권2호
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• pp.309-323
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• 2016

As the forefront of structural design method, capacity spectrum method can be applied conveniently, and through this method, deformation demand of structure can be considered. However, there is no research for the seismic application in the structure of sheet pile retaining wall to report. Therefore, focusing on laterally loaded stabilizing sheet pile wall, which belongs to flexible cantilever retaining structure and meets the applying requirement of capacity spectrum method from seismic design of building structure, this paper studied an approach of seismic design of sheet pile wall based on capacity spectrum method. In the procedure, the interaction between soil and structure was simplified, and through Pushover analysis, seismic fortification standard was well associated with performance of retaining structure. In addition, by comparing the result of nonlinear time history analysis, it suggests that this approach is applicable.

• 화약ㆍ발파
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• 제23권3호
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• pp.75-82
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• 2005

여러 발파공학자들이 현지 암반의 지역적 특성을 고려한 발파를 위해 적용할 수 있는 나름대로의 방법론들을 개발하고 있는 실정이다. 그러나 대부분의 방법론들이 지역적인 암반 특성을 반영할 수 있도록 체계화되어 있지 못할 뿐만 아니라 발파자의 관찰과 경험에만 주로 의존한다는 단점이 있다. 본 연구에서는 현지암반의 고유한 공학적 특성을 고려할 수 있도록 Lilly가 제안한 발파지수(blastability index) 개념을 도입하여 발파설계 인자를 도출할 수 있도록 시도하였다. 발파지수 산정 시에는 암반 자체의 공학적 특성뿐만 아니라 절리분포 특성도 반영이 되므로 현지 여건에 부합될 수 있는 발파암 분류가 가능하고, 합리적인 발파설계를 수행하는 데에 도움이 될 것으로 기대된다.

• 품질경영학회지
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• 제37권3호
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• pp.39-53
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• 2009

This paper suggests a new process structuring method, which we call process modularization, for decomposing and grouping activities in a process. Above all, we propose the concept of a module that is a group of activities positioned on the same flow before and after control constructs. Since activities in a module are relatively strongly interrelated with one another, it is important to take into consideration of these together. A design structure matrix (DSM) is used to structure the process because it has a lot of advantages in process modeling and analysis. We developed two algorithms: the restricted topological sorting (RTS) algorithm for ordering activities and the module finding (MF) algorithm for detecting modules in a process, which utilize the DSM. The suggested approach enables a firm's manager to design and analyze the process effectively. We also developed a supporting tool to accelerate the progress of process modularization. The supporting tool aids the process manager in finding the module and understanding the process structure easily. An illustrative example is addressed to show operations of the suggested approach.

• 한국멀티미디어학회논문지
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• 제17권6호
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• pp.759-768
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• 2014

Recently crime against children is emerged as a serious social problem. Children should be protected in social. However, they have become major targets of the crime, as sexual abuse, abduction, abuse, domestic violence, school violence and so on. To solve these problems, it is important to educate crime prevention for children all above. Entertainment is one of the edutainment's elements. It attracts voluntary participation, immersion, and continuous learning from children. Edutainment contents for prevention of crime against children are far less fully studied than that of school subject as Mathematics, English, and so on. There is no serious study on edutainment contents for prevention of crime against children, as well as base study and approach way. Now more than ever, safety needs are strongly demanded in society. Accordingly, study on edutainment contents for prevention of crime against children have been demanded more than ever. In this paper we shall see basic approach principles and planning process of web-based edutainment contents for prevention of crime against children. This study lays the foundation for future work on edutainment contents for prevention of crime against children.

• Steel and Composite Structures
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• 제14권3호
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• pp.295-312
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• 2013

In this paper, a simplified approach based on critical temperature for fire resistance design of steel-concrete composite beams is proposed. The method for determining the critical temperature and fire protection of the composite beams is developed on the basis of load-bearing limit state method employed in current Chinese Technical Code for Fire safety of Steel Structure in Buildings. Parameters affecting the critical temperature of the composite beams are analysed. The results show that at a definite load level, section shape of steel beams, material properties, effective width of concrete slab and concrete property model have little influence on the critical temperature of composite beams. However, the fire duration and depth of concrete slab have significant influence on the critical temperature. The critical temperatures for commonly used composite beams, at various depth of concrete and fire duration, are given to provide a reference for engineers. The validity of the practical approach for predicting the critical temperature of the composite beams is conducted by comparing the prediction of a composite beam with the results from some fire design codes and full scale fire resistance tests on the composite beam.

• Computers and Concrete
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• 제17권5호
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• pp.579-596
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• 2016

This paper describes a method of the refined plastic hinge approach in the framework of the higher-order element formulation that can efficaciously evaluate the limit state capacity of a whole reinforced concrete structural system using least number of element(s), whereas the traditional design of a reinforced concrete structure (i.e. AS3600; Eurocode 2) is member-based approach. Hence, in regard to the material nonlinearities, the efficient and economical cross-section analysis is provided to evaluate the element section capacity of non-uniform and arbitrary concrete section subjected to the interaction effects, which is helpful to formulate the refined plastic hinge method. In regard to the geometric nonlinearities, this paper relies on the higher-order element formulation with element load effect. Eventually, the load redistribution can be considered and make full use of the strength reserved owing to the redundancy of an indeterminate structure. And it is particularly true for the performance-based design of a structure under the extreme loads, while the uncertainty of the extreme load is great that the true behaviour of a whole structural system is important for the economical design approach, which is great superiority over the conservative optimal strength of an individual and isolated member based on traditional design (i.e. AS3600; Eurocode 2).

• 한국강구조학회 논문집
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• 제12권1호통권44호
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• pp.93-102
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• 2000

본 연구는 부구조화에 기초한 계층적 접근방법을 이용하여 프레임구조에 대한 설계민감도해석과 최적화를 수행한다. 이 방법의 개념적 틀은 유형의 구조계와 무형의 설계과정을 계층적으로 모델링하고 부구조화해석과 다단계최적화를 결합하는데 있다. 여기서 해석과 총합을 위한 수학적 모델은 공통의 부구조화체계와 기반위에서 설정된다. 이러한 수학적 구조적 기반위에서 모듈화된 거동해석과 민감도해석 및 최적화과정이 서로 연계되고 통합된다. 여기서 설계민감도정보는 상태공간방법으로 계산되고, 시스템단계의 활성조건과 중량비 규준을 통해 부구조들의 조율이 이루어진다. 대형프레임구조에 대한 수치 예제들을 통해 본 연구의 타당성 및 효율성과 유용성을 검증한다.

• 대한조선학회논문집
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• 제48권5호
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• pp.426-434
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• 2011

Accurate weight prediction methods are an essential of the ship design in both ship cost managements and performance satisfactions. When no parent or similar ships are available, an adequate method of the ship weight estimating is required. In this study, there was carried out to develop the ship weight estimating method for the preliminary design phase. The weight estimating methods were first surveyed by the references and summarized their characteristics. The weight estimation method by statistical approach was developed for the container ship because the containerized transportation markets is gradually growing and ship's size and loading capacity are rapidly enlarged. The correlation analysis and the multiple regression analysis were used for developing the weight estimating method. As a results of evaluating the developed method, the error ratio of the variation between estimated weight and ship's data was about 5%. And it was only 1% difference with the calculating weight of conceptual design results by shipyard design team that the estimating weight of ultra-large container ship was predicted by the developed method.