• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1183-1188
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• 2009

Estimating project costs during the early stage of conceptual planning is very important when deciding whether to approve the project and allocate an appropriate budget. However, due to greater uncertainties involved in a project, it is challenging to estimate costs during this initial stage within a reasonable tolerance. This paper attempts to develop a cost-estimate model for public road projects under these circumstances and limitations. In the conceptual planning stage of a road project, there is only limited information for cost estimation, for example, such input data as total length of the route, origin and destination, number of lanes, general geographic characteristics of the route, and other basic attributes. This implies that the model should individuate suitable but restricted information without considering detailed features such as quantity of earthwork and a detailed route of a given condition. With these limited facts, this paper applies a case-based reasoning (CBR) method to solve a new problem by deriving similar past problems, which in turn is used to estimate the cost of a given project based on best-fitted previous cases. To develop a CBR cost-estimate model, the authors classified 8 representative variables, including project type, the number of lanes, total length, road design grades, etc. Then, we developed the CBR model, primarily by using 180 actual cases of public road projects, procured over the last decade. With the CBR model, it was found that the degree of error in estimation can be reasonably reduced, to below approximately 30% compared to the final costs estimated upon the completion of detailed design.

• 한국통신학회논문지
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• 제37권7C호
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• pp.584-591
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• 2012

Distributing a Certificate Revocation List (CRL) quickly to all vehicles in the system requires a very large number of road side units (RSUs) to be deployed. In reality, initial deployment stage of vehicle networks would be characterized by limited infrastructure as a result in very limited vehicle to infrastructure communication. However, every vehicle wants the most recent CRLs to protect itself from malicious users and malfunctioning equipments, as well as to increase the overall security of the vehicle networks. To address this challenge, we design and implement a nomadic device based CRL acquisition method using nomadic device's communication capability with cellular networks. When a vehicle could not directly communicate with nearby RSUs, the nomadic device acts as a security mediator to perform vehicle's security functions continuously through cellular networks. Therefore, even if RSUs are not deployed or sparsely deployed, vehicle's security threats could be minimized by receiving the most recent CRLs in a reasonable time.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.606-615
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• 2009

Estimating the reasonable construction-cost according to the construction phase in public construction is an important element for securing and executing a national budget efficiently. As a general rule, the predetermined cost of construction is estimated at the end of the design of the target structure. Therefore, it seems to be a considerably difficult problem to estimate the approximate cost of construction, only with its basic information of the bridge in the design planning phase and the early design stage where we can not have specific detailed-section of the target structure. In this paper, we present the calculation of construction-cost in the planning phase based on the analysis of factors affecting the cost of construction conducted in the previous study. Beside, to estimate the cost of construction in early design phase, we would like to present the calculation of construction-cost in the early design phase by executing the analysis of data collected from 61 steel box bridges. It was found from the result of study that the estimated cost of construction gained by the calculation of construction-cost in this paper reduces the error between the real cost of construction and that by the existing method of using.

• 대한기계학회논문집
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• 제14권3호
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• pp.656-663
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• 1990

본 연구에서는 이러한 해석적 근사해를 이용한 스터링기관의 최적설계조건에 관하여 취급하고자 한다. 단열해석의 결과를 대응하는 등온해석과 비교, 고찰함으로 써 방법에 따른 조건의 차이를 보이고 주요 설계인자의 성능에 미치는 영향을 규명한 다. 또한, 제인자에 따른 기관성능의 변화추이가 편리하게 표시될 수 이씨는 일종의 성능선도(performance map)를 작성하고자 한다.

• 한국전산구조공학회논문집
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• 제14권3호
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• pp.317-327
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• 2001

이 논문에서는 이동식 지보를 이용한 MSS공법에 의해 건설되는 콘크리트 교량의 설계 모멘트를 산정하기 위한 관계식을 제안하고 있다. 각 시공 단계에 따른 시간 의존적 거동해석을 통해 교량의 부재력 변화와 처짐 변화를 고찰하였으며 변위와 하중조건을 토대로 한 지배방정식을 구성한 후 복잡한 장기 거동 해석 없이 탄성 해석 결과를 토대로 설계 부재력과 임의의 시간 경과 후 모멘트 변화를 예측할 수 있는 관계식을 구성하였다. 나아가 다양한 예제 해석을 통해 제안한 관계식의 적용성을 검증하였으며 모멘트 포락선을 토대로 보다 합리석인 설계 부재력의 산정 방안을 소개하였다.

• 한국산업융합학회 논문집
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• 제23권2_2호
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• pp.289-299
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• 2020

The composition of convergence cross-section of the material is a technique that provides reasonable design and construction of structures. It is frequently used in medium-sized bridges and architectural structures. However, the structural behavioral spare capacity enhancement of the structure by the application of the convergence cross-section is still limited by the expandability due to the limiting state of each material. In order to overcome these limitations, this study reasonably analyzed the construction stages before and after the convergence cross-section constructed and developed a technique for forming multi-point boundary conditions using struts, which are compression members. Based on the existing cases, a reasonable construction step for forming the material composite section of the entire structural system of the structure was derived, and a numerical analysis model for a specific part was constructed to analyze the behavior of the strut application. As a result of this study, the effect of reducing the sectional force of 7.40% in beam-column joint and 6.31% in the center of girder was derived, and the deflection, which is a measure of the serviceability of the structure, improved by 54.41% from the installation and dismantling of strut members at each construction stage.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.105-108
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• 2005

The radiated noise from the automotive intake system should be predicted at the design stage. To this end, the precise measurement of in-duct acoustic source parameters of the intake system, i.e., the source strength and source impedance, is essential. Most of previous works on the measurement of acoustic source parameters were performed under a fixed engine speed condition. However, the requirement of vehicle manufacturer is the noise radiation pattern as a function of engine speed. In this study, the direct method was employed to measure the source parameters of engine intake system under a fixed engine speed and engine run-up condition. It was noted that the frequency spectra of source impedance hardly changes with varying the engine speed. Thus, it is reasonable to calculate the source strength under the engine run-up condition by assuming that source impedance is invariant with engine speed. Measured and conventional source models, i.e., constant pressure source, constant velocity source, and non-reflective source, were utilized to predict insertion loss and radiated sound pressure level. A reasonable prediction accuracy of radiated sound pressure level spectra from the intake system was given in the test vehicle when using the measured source characteristics which were acquired under the operating condition.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.504-509
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• 2011

Recently, construction projects are very complicated and diverse such as high-rise buildings and big bridges, etc. These complicated projects call for a system which can effectively generate productive ideas and activities. Value Engineering (V.E.) activity within construction projects is a necessity for systematic design management and to improve construction ability. This need in the construction industry has required a regular implementation of VE into construction projects. For this reason; America, South Korea, and some other nations have adopted VE applications which control the baseline investments of the construction projects. The process of VE activity is a preferred system and a reasonable alternative. In particular, idea generation within these projects is an important stage in the VE job plan. In this study, VE idea patterns are extracted through best practice analysis from VE cases of road construction projects. Next, we suggest an idea hierarchy model to be used in conjunction with VE idea patterns. This model is supported by reasonable idea generation in VE activity of construction projects. Finally, this model could possibly be the outcome of successful VE results.

• 한국지반공학회지:지반
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• 제14권5호
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• pp.173-180
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• 1998

본 논문은 연약한 기초지반위의 토목섬유 보강제방의 2차원 안정해석을 위한 설계도표를 제시한다. 반복계산을 수행하기 위하여 보강제방의 요구되어지는 안전율에 필요한 보강재의 인장력을 산정하는 프로그램이 개발되었으며, 이 프로그램은 여러개의 토층과 토질로 이루어진 상황에도 사용될 수 있다. 도식화된 단면에 대하여 많은 계산결과들이 만들어 졌으며, 그 결과들로서 설계도 I를 만들었으며, 정적인 경우와 지진하중을 고려할 경우에도 적용시킬 수 있다. 예비설계단계에서 이러한 도표들을 이용하여 보강제방에 대한 비교적 정확한 보강재의 인장력을 근사적으로 구할 수 있으며, 실시설계단계에서는 개발된 프로그램에 의하여 정확한 결과를 산정할 수 있다.

• 벤처창업연구
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• 제9권4호
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• pp.155-161
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• 2014

본 연구에서는 신제품개발의 실시에 있어서 가장 중요한 기능분석의 단계를 제품의 설계 단계에서부터 소비자의 만족도를 조사하여 반영하였다. 품질기능전개를 이용하여 전개함으로서 원가절감과 품질개선의 합리적인 기능분석을 실시하고자 하는데 그 목적이 있다. 가치공학과 품질기능전개(QFD: Quality Function Deployment) 의 상호연계에 대한 필요성과 적합성을 분석하였다. 사례연구에서는 이러한 이론적인 배경 하에 품질기능전개를 이용하여 VE 기능 분석을 의료기기 제품에 적용하였다. 본 연구결과 소비자의 만족도와 품질기능전개를 이용하여 나타난 제품의 가치가 연구결과와 일치하고 있음을 파악하였다.