• 대한기계학회논문집A
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• 제29권1호
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• pp.45-52
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• 2005

A general approximate optimization technique by sequential design domain(SDD) did not save response values for getting an approximate function in each step. It has a disadvantage at aspect of an expense. In this paper, previous response values are recycled for constructing an approximate function. For this reason, approximation function is more accurate. Accordingly, even if we did not determine move limit, a system is converged to the optimal design. Size and shape optimization using approximate optimization technique is carried out with SDD. Algorithm executing Pro/Engineer and ANSYS are automatically adopted in the approximate optimization program by SDD. Convergence criterion is defined such that optimal point must be located within SDD during the three steps. The PLBA(Pshenichny-Lim-Belegundu-Arora) algorithm is used to solve approximate optimization problems. This algorithm uses the second-order information in the direction finding problem and uses the active set strategy.

• 디자인학연구
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• 제2권1호
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• pp.117-130
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• 1989

Evaluation is to be seen a~ a central component of design activity. It is an attempt to ensure that the proposal which arises is accepted and that the resulting artefact itself suited to its purposes in practice. Recent surveys of Evaluation show that most methods require quantitative and explicit attributes. Always a significant part of the attributes of design proposals is qualitative. Therefore we need some study that convert qualitative attributes into quantitative scale values, because in many cases con\ulcornerclusions can be drawn about the order of the overall value of the design proposals. Following to Thurstone's psychological scaling methods, attributive values are assigned by ruting scale methods, met, hod of rank-order and method of paired comparisons. The problem of psycho\ulcornerlogical scaling is then to determine whether the stimuli can be ordered on a psychological continuum with respect to the degree of the attributes each possesses. The law of comparative judgement assumes that for a given stimulus there is associated a most frequently aroused or modal discriminal process on a psychological continuum. This paper is based upon the premise that the modal discriminul process will also be the same as the mean or median of the distribution.The objective of this paper is to argue for an acceptance of qualitative approaches to the evalua\ulcornertion of Design as a complement to the existing quantitative techniques. The scale values of 10 attri\ulcornerbutes \ulcorner(1) originality, (2) aesthetics, (3) satisfaction, (4) effeciency, (5) function, (6) size, (7) texture, (8) simplicity, (9) symbol, and (10) facility) in case of TV sets are obtained and their interactions are examined.

• Earthquakes and Structures
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• 제2권1호
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• pp.65-88
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• 2011

A new method for the seismic design of plane steel moment resisting frames is developed. This method determines the design base shear of a plane steel frame through modal synthesis and spectrum analysis utilizing different values of the strength reduction (behavior) factor for the modes considered instead of a single common value of that factor for all these modes as it is the case with current seismic codes. The values of these modal strength reduction factors are derived with the aid of a) design equations that provide equivalent linear modal damping ratios for steel moment resisting frames as functions of period, allowable interstorey drift and damage levels and b) the damping reduction factor that modifies elastic acceleration spectra for high levels of damping. Thus, a new performance-based design method is established. The direct dependence of the modal strength reduction factor on desired interstorey drift and damage levels permits the control of deformations without their determination and secures that deformations will not exceed these levels. By means of certain seismic design examples presented herein, it is demonstrated that the use of different values for the strength reduction factor per mode instead of a single common value for all modes, leads to more accurate results in a more rational way than the code-based ones.

• 한국지반신소재학회논문집
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• 제23권2호
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• pp.9-17
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• 2024

연약지반의 성토나 구조물 축조할 때, 지반의 침하와 안전에 대한 관리가 중요하다. 하지만 실제 지반의 거동과 설계 계획과는 현저한 차이를 보일때가 많다. 본 연구에서는 연약지반 설계시 이론식에 의해 추정되는 설계침하량과 시공시 게측되는 계측침하량의 차이를 통한 침하량 예측을 통하여 그 결과를 비교,분석하고자 하였다. 집중공 18개소에 대한 침하량 분석결과, 역해석 침하량은 계측침하량과 유사한 결괏값을 확인하였으나, 설계침하량의 경우 계측침하량 대비 높은 침하량 값을 확인하였다. 설계침하량의 경우 계측값을 통해 도출된 역해석 침하량과 실내침하량 보다 1.2~1.4배 이상 높은 값을 보였다. RMSE 분석결과, 설계침하량의 경우 0.6212m, 역해석침하량의 경우 0.1697m로 확인되었다. 역해석침하량과 계측침하량의 차이가 설계침하량과 계측침하량의 차이보다 70%이상 낮은 결과를 보였으며, 이는 역해석침하량 값이 설계침하량보다 더 낮은 오차율을 보인다는 것을 확인할 수 있다.

• 생물환경조절학회지
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• 제27권4호
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• pp.277-284
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• 2018

온실의 냉난방부하 산정을 위해 설계자가 선택해야할 주요 변수들에 대하여, 이들 설계 변수가 냉난방부하에 미치는 영향을 평가하기 위해서 각각의 설계 변수값을 변화시키면서 시뮬레이션을 실시하였으며, 이를 바탕으로 특별히 선택에 주의를 기울여야 할 설계 변수를 제안하였다. 난방부하에 가장 큰 영향을 미치는 설계 변수는 피복재의 열관류율이고, 다음으로 설계외기온인 것으로 나타났다. 연동수에 따른 설계 변수의 영향은 차이가 거의 없는 것으로 나타났다. 단동 온실의 경우에는 지중전열 관련 설계 변수의 영향을 무시할 수 없을 것으로 생각되지만, 연동 온실의 경우에는 지중전열 관련 변수 및 틈새환기율의 영향이 미미한 것으로 판단되었다. 냉방부하에 가장 큰 영향을 미치는 설계 변수는 온실내로 유입되는 일사량과 증발산계수이고, 다음으로 실내외 기온차, 환기율인 것으로 나타났다. 설계 변수의 영향은 단동 온실과 연동 온실에서 큰 차이를 보였으나, 연동수에 따른 차이는 거의 없는 것으로 나타났다. 피복재의 열관류율은 단동 온실이나 연동 온실 모두 영향이 미미한 것으로 나타났지만, 실내외 기온차 및 환기율의 경우에는 냉방부하에 미치는 영향을 무시할 수 없을 것으로 생각되며, 특히 연동 온실에서 그 영향이 더 큰 것으로 판단되었다. 냉방부하를 산정할 때 실내 목표온도를 낮게 설정할수록 설계 변수의 선택에 신중해야 한다. 특히, 실내 목표온도를 외기온 보다 낮게 설정하면 환기율 및 열관류율 값이 냉방부하를 증가시키는 방향으로 바뀌므로 더욱 주의해야 한다. 환기율이 낮을 때는 설계 변수 중 설계일사량과 증발산계수의 선택에 주의해야 하고, 환기율이 높을 때는 실내 설정온도와 설계외기온의 선택에 신중을 기해야 한다.

• 한국구조물진단유지관리공학회 논문집
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• 제4권4호
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• pp.171-180
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• 2000

This study aims to present a more reasonable control value than the exiting one by comparing and analyzing control values and field instrumentation values of the whole excavation depth of the four case sites using geometric averaging as a statistical method. The range of the study is confined to three things: (1) the axial force of the braced excavation walls among a variety of items prescribed in the control values by stress deformation of walls and adjacent structures; (2) by approximation of the allowable and design value; (3) and by safety factor. As a res it is desirable to revise "(Long term allowable stress + Short term allowable stress)/2 ~ Short term allowable stress," presented in the present control values by stress deformation of walls and adjacent structures, to "(Long term allowable stress + Short term allowable stress)/5 ~ (Short term allowable stress)/3." The result also shows that since there is a difference of about 3.5%, it is not necessary to revise 70, 90, and 100 percent of LEVEL I, II, and III, prescribed in the control values by the allowable and design value approximation. In addition, modifying the control value by the safety factor, now 1.07, is unnecessary, although it varies little difference from the present value.

• Earthquakes and Structures
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• 제20권4호
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• pp.389-403
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• 2021

Skewed bridges, being irregular structures with complicated dynamic behavior, are more susceptible to earthquake damage. Reliable seismic-resistant design of skewed bridges can be achieved by accurate determination of nonlinear seismic demands. However, the effect of geometric characteristics on the response modification factor (R-factor) is not accounted for in bridge design practices. This study attempts to investigate the effects of changes in the number of spans, skew angle and bearing stiffness on R-factor values and to assess the seismic fragility of skewed bridges. Results indicated that changes in the skew angle had no significant effect on R-factor values which were in consonance with code-prescribed R values. Also, unlike the increase in the number of spans that resulted in a decrease in the R-factor, the increase in bearing stiffness led to higher R-factor values. Findings of the fragility analysis implied that although the increase in the number of spans, as well as the increase in the skew angle, led to a higher failure probability, greater values of bearing stiffness reduced the collapse probability. For practicing design engineers, it is recommended that maximum demands on substructure elements to be calculated when the excitation angle is applied along the principal axes of skewed bridges.

• Journal of the Korean Wood Science and Technology
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• 제49권1호
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• pp.93-102
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• 2021

In this article, withdrawal resistances of axially loaded self-tapping screws on wood products made by Korean Larch were predicted with existing estimation equation, and compared with experimental test data. The research was required because no design methodology for the withdrawal resistance of self-tapping screw is present in Korean building code (KBC). First, the withdrawal resistance of wood screw was predicted to use the withdrawal design value estimation equation in National Design Specification for Wood Construction (NDS). Second, three types of wood products, solid wood, cross-laminated timber (CLT) and plywood, were utilized for withdrawal test. For decades, various engineered wood products have been developed, especially cross-laminated timber (CLT) and hybrid timber composites such as timber composites of solid wood and plywood. Therefore, CLT and plywood were also investigated in this study as well as solid wood. Finally, the predicted values were compared with experimentally tested values. As the results, the tested values of solid wood and CLT were higher than the predicted values. In contrast, it is inaccurate to predict withdrawal resistance of plywood since prediction was higher than tested values.

• 한국생활과학회지
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• 제13권2호
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• pp.291-300
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• 2004

The purposes of this study were to research the clothing shopping orientations and the utilizations of information sources according to values of male consumer aged between the 20's and the 30's. The data were analyzed by factor analysis, one-way ANOVA, Duncan's multiple range test, x2- test, Pearson's correlation. The results of the study were as follows: 1. Male consumer's values were classified into 2 factors, and consisted of three groups. 2. There were significant differences among groups according to demographics variables. 3. Clothing shopping orientations were classified into 6 factors and information sources were classified into 3 factors. 4. There were relationships between male consumer's values, clothing shopping orientation, and utilization of information sources.

• Wind and Structures
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• 제8권4호
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• pp.295-307
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• 2005

The paper describes the work of the IAWE Working Group WBG - Reliability and Code Level, one of the International Codification Working Groups set up at ICWE10 in Copenhagen. The following topics are covered: sources of uncertainties in the design wind load, appropriate design target values for the exceedance probability of the design wind load for different structural classes with different consequences of a failure, yearly exceedance probability of the design wind speed and specification of the design aerodynamic coefficient for different design purposes. The recommendations from the working group are summarized at the end of the paper.