• 어항어장
• /
• s.2
• /
• pp.86-127
• /
• 1988

버트리스 푸팅 케슨(Buttress footing caisson) 및 상형 푸팅 케슨의 역학특성을 해명하고 구조설계법을 검토할 목적으로 재하실험을 실시했다. 재하실험에는 배근의 제약등을 고려해서 실구조물의 1/4정도의 대형모형공시체를 사용해서 푸팅부를 중심으로 해석하기위해 푸팅에 선분포하중을 재하했다. 유한요소법에 따른 선형구조해석을 실시하여 변위, 단면력과 한계상황설계법에서의 산정식에서 얻어진 단면내력과를 비교하여 동설계법의 케슨구조물에 대한 적용성에 관하여 고찰했다. 이 보고로써 얻어진 주요한 결론은 아래와 같다. (1) 재하실험에 의하면 버트리스 푸팅공시체의 파괴형식은 버트리스부의 철근에 연한 부착할열파괴였다. 또 상형푸팅공시체에서는 푸팅부의 내면전단파괴였다. 양구조물을 설계할 때는 종래의 면외력만의 검토뿐아니라 면내력도 적절히 평가할 필요가 있다. (2) 양공시체 함께 푸팅 케슨본체와의 접합부 및 푸팅과 상자옆쪽의 벽과의 접합부에 변형이 일어나 종래의 판구조설계에서 가정하고 있는 판주변의 고정조건이 만족되지 않았다. 따라서 케슨구조물의 구조해석에서 구조전체계를 취급할 필요가 있고 부재단위에서는 단면력을 과대 또는 과소로 산정할 우려가 있다. (3) 철근강복시정도까지는 구조전체계를 모델화한 유한요소법에 의한 선형구조해석결과와 실험결과가 잘 일치했다. (4) 한계상태설계법에서의 굽음내력, 전단내력 및 구열폭의 산정식은 실험결과와 비교해서 어느쪽이나 안전측의 치를 부여했다.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.6 no.6
• /
• pp.403-412
• /
• 2016

As transaction and investment using technology are vitalized, the need for objective standards for the technology is increasing. Current technology value evaluation system is limited lacking reliability and objectivity. Besides the traditional evaluation methodology which are market approach, income approach and cost approach other diverse evaluation methodology such as real option method and royalty calculation method are being studied; however currently there are no dominant evaluation methodology in the market. Same value evaluation system cannot be applied between similar technologies because value of technology is relatively decided based on the target. Approaching through collective intelligence and crowd sourcing, in meaning of majority participant's decision can make objective and better result than handful of experts, suggest alternative to problems of such matter above. By grafting the four types of crowd sourcing model which are Wisdom, Voting, Funding and Creation, this paper will discuss the ways to enhance the objectivity of technology evaluation through direct evaluation utilizing expert group and the public's indirect evaluation.

• Korean journal of applied entomology
• /
• v.61 no.4
• /
• pp.659-664
• /
• 2022

Putrescine generated by the action of microorganisms in the decay generally used as a measure of freshment in food. However, the analytical method of putrescine in freeze-dried royal jelly has not yet been established. In the present study, the UPLC method for putrescine in lyophilized royal jelly was established using C18 column. The newly established method was able to analyze putrescine accurately within 7 minutes and was validated by analytical parameters such as specificity, linearity, precision, accuracy, limit of detection, and limit of quantification. These results provide for the analytical method to evaluate the level of freshment in freeze-dried royal jelly, which will useful in further studies of safety verification.

• Proceedings of the KIPE Conference
• /
• 2015.11a
• /
• pp.101-102
• /
• 2015

이차전지의 수명 평가는 크게 Cycle life test 와 Calendar life test로 나뉘어져서 평가 되고 있다. Cycle life test로 수명 검증을 위해서는 일반적으로 3000 사이클 이상 테스트를 진행 하여야 하지만 이 방법은 시간이 장기화 되어 신뢰성 검증 및 새로운 부품 적용에 한계가 따른다. 따라서 본 논문에서는 고온 챔버 및 사이클 시험기를 사용하여 빠른 시간 내에 평가를 할 수 있는 가속시험법을 적용하여 수명을 평가 한 연구결과를 발표하고자 한다.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.6
• /
• pp.606-613
• /
• 2005

The badge-type diffusive sampler for the measurement of formaldehyde in indoor air using three types of colorimetric methods such as chromotrophic acid(CTA), 3-methyl-2-benzothiazolinone hydrazone(MBTH), and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole(AHMT) method. The washing of the collection filter with several cleaning solution was effected with satisfactory results, regardless of the types of cleaning solutions. The concentrations of absorbance solution in each colorimetric method were experimentally determined by considering the sampling rates. The variation blank values in each colorimetric method was below 15%. As compared with CTA and AHMT methods, the reproducibility of MBTH method was excellent and was below 10% relative standard deviation. The collected formaldehyde mass and time-weighted concentration had a good correlation (correlation coefficient > 0.93). The limit of detection and limit of quantitation, and minimum sampling time were closely correlated to the sampling rates for the measurement of formaldehyde in each method.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.25 no.5
• /
• pp.317-326
• /
• 2013

Probabilistic design methods can consider uncertainties of design variables and are widely used in the design of vertical breakwaters. The probabilistic design methods include a partial safety factor method, reliabilitybased design method, and performance-based design method. Especially the performance-based design method calculates the accumulated sliding distance during the lifetime of the breakwater or during a design storm. Recently a time-dependent performance-based design method has been developed based on the first-passage probability of individual sliding distance during a design storm. However, because the allowable criteria in the first-passage probability method are not established, the stability of structures cannot be quantitatively evaluated. In this study, the allowable first-passage probabilities for two limit states are proposed by calculating the first-passage probabilities for the cross-sections designed with various water depths and characteristics of extreme wave height distributions. The allowable first-passage probabilities are proposed as 5% and 1%, respectively, for the repairable limit state (allowable individual sliding distance of 0.03 m) and ultimate limit state (allowable individual sliding distance of 0.1 m). The proposed criteria are applied to the evaluation of the effect of wave-height increase due to climate change on the stability of the breakwater.

• Journal of Soil and Groundwater Environment
• /
• v.12 no.5
• /
• pp.1-6
• /
• 2007

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1993.10a
• /
• pp.10-10
• /
• 1993

본 연구에서는 다품종(multiple products) 다단계(multi-stage) 흐름 생산시스템에서의 제품별 로트 투입순서결정무제를 다루었다. 다단계 흐름 생산시스템의 투입순서 결정문제에 대한 기존연구는 각 단계의 기계대수가 1대인 경우에 관한 것이 대부분이지만, 본 연구에서는 각 단계의 기계대수가 복수이고 각 제품의 생산량이 로트로 주어지며, 또한 각 단계마다의 이송이 로트로 이루어지는 것이 아니라 1단위로 이루어지는 생산시스템을 대상으로 하였다. 그리고 각 제품의 생산준비기간은 투입순서와 관계 없이 일정하며 앞 단계에서 제품이 도착하지 않더라도 생산준비는 먼저 수행될 수 있다고 가정하였다. 제품별 로트 투입순서 결정문제에서 사용된 성능평가기준(performance measure)은 총작업소요시간(makespan)이며 순열투입순서(permutation schedule)만을 대상으로 하였다. 결정기법으로는 투입순서 결정문제에서 효율적인 것으로 알려져 있는 분지한계법(Branch & Bound)이 사용되었으며 분지한계법에서 이용되는 부분투입순서(partial sequence)에 대한 하한값(lower bound)을 제시하였다. 제시된 기법을 사용하면 현실적인 크기의 제품별 로트 투입순서 결정문제를 적당한 시간내에 충분히 해결할 수 있을 것으로 보인다. 제시된 해법으로 해결된 수치예제가 주어져 있다.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.36 no.1
• /
• pp.39-53
• /
• 1994

To investigate the behaviour of the embankment on very soft foundation reinforced geotex- files,the laboratory model test in order to analyze the elementary effects of geotextile reinfor- cement and the finite element program analyzing the stresses and deformations characteristics was carried out. A two-dimensional nonlinear finite element program called GEOTEXT(a modification of ISBILD) for the static analysis of embankment on very soft foundation reinforced geotextiles has been developed. Both linear and nonlinear hyperbolic stress-strain soil models are inclu- ded, and incremental and stage construction can be simulated. However, the program GEO- TEXT is not developed herein as an adaptable design tool for practicing engineer. It was found that the geotextile reinforcement significantly reduced the shear stresses in the foundation and decreased the vertical differential settlements at the top of the embank- ment. This influence was more pronounced as the tensile strength of the geotextile was increased.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.4A
• /
• pp.647-657
• /
• 2006

Probabilistic Risk Assessment considering statistically random variables is performed for the preliminary design of a Cable Stayed Bridge, which is Prestressed Concrete Bridge consisted of cable and plate girders, based on the method of Working Stress Design and Strength Design. Component reliabilities of cables and girders have been evaluated using the response surface of the design variables at the selected critical sections based on the maximum shear, positive and negative moment locations. Response Surface Method (RSM) is successfully applied for reliability analyses for this relatively small probability of failure of the complex structure, which is hard to obtain through Monte-Carlo Simulations. or through First Order Second Moment Method that can not easily calculate the derivative terms of implicit limit state functions. For the analysis of system reliability, parallel resistance system consisting of cables and plate girder is changed into series connection system and the result of system reliability of total structure is presented. As a system reliability, the upper and lower probabilities of failure for the structural system have been evaluated and compared with the suggested prediction method for the combination of failure modes. The suggested prediction method for the combination of failure modes reveals the unexpected combinations of element failures in significantly reduced time and efforts compared with the previous permutation method or system reliability analysis method, which calculates upper and lower bound failure probabilities.