• Advances in Computational Design
• /
• 제7권4호
• /
• pp.297-319
• /
• 2022

Due to their natural and social revelation, also their ease and flexibility, human collective behavior and teamwork sports are inspired to introduce optimization algorithms to solve various engineering and scientific problems. Nowadays, meta-heuristic algorithms are becoming some striking methods for solving complex real-world problems. In that respect in the present study, the authors propose a novel meta-innovative algorithm based on soccer teamwork sport, suitable for optimization problems. The method may be referred to as the Soccer League Optimization-based Championship Algorithm, inspired by the Soccer league. This method consists of two main steps, including: 1. Qualifying competitions and 2. Main competitions. To evaluate the robustness of the proposed method, six different benchmark mathematical functions, and two engineering design problem was performed for optimization to assess its efficiency in achieving optimal solutions to various problems. The results show that the proposed algorithm may well explore better performance than some well-known algorithms in various aspects such as consistency through runs and a fast and steep convergence in all problems towards the global optimal fitness value.

• 한국석유지질학회:학술대회논문집
• /
• 한국석유지질학회 2001년도 제8차 학술발표회 발표논문집
• /
• pp.28-46
• /
• 2001

천연가스는 탄화수소가스와 질소$(N_2)$, 황화수소$(H_2S)$ 및 이산화탄소$(CO_2)$ 등의 혼합체로서 연소 시 공해물질이 거의 발생하지 않는 무공해 청정연료이며(Beggs, 1984), 현재 환경 문제가 전 세계적으로 급격히 대두되는 시점에서 천연가스는 그 청정성으로 인하여 사용량이 급증하고 있는 실정이다. 과거 Hubbert의 연구(Hubbert, 1974)에 의하면 천연가스는 매우 급속히 고갈되는 자원으로 평가되었으며 이러한 평가는 1980년대에 가스 가격 인상과 사용량의 제한을 유도하였다. 그 후, 지질학적 기반을 바탕으로 한 천연가스 자원 연구에서 Hubbert의 평가에 포함되지 않았던 가스 자원이 규명되었는데 이러한 새로운 가스자원은 비재래 가스 (Unconventional Gas), 기존 저류층의 추가 매장량과 심부 지역에 존재하는 심부 천연가스 (Deep Natural Gas) 등이다. 이러한 새로운 매장량의 추가로 인하여 천연가스의 미래는 밝아졌으며, 저렴한 가격의 안정된 가스 공급을 보장받게 되었다. 심부 천연가스는 15,000 ft $(4,572{\cal}m)$ 이상의 지하에 존재하는 천연가스로서 미국 지질 조사소인 U.S. Geological Survey(USGS)의 1995년 연구 결과로 볼 때, 1,412조 입방피트의 기술적으로 회수 가능한 천연가스 가운데 114조 입방피트가 심부 퇴적 분지에 존재하는 천연가스인데 이러한 심부 가스는 광범위하게 분포되어 있고 다양한 지질학적 환경을 가짐을 알 수 있다 (Kuuskraa, 1998). 심부 가스는 1995년 미국의 전체 천연가스 공급량 가운데 $6.7\%를 차지하였으며 2015년까지 $18.7\%로 증가할 전망이다 (Cochener & Brandenburg, 1998). 그러나 심부가스 개발은 성공률이 낮은 사업인데 그 이유는 투자비가 비싸고 개발하더라도 높은 비율의 비 생산정 (dry hole)이 발생하기 때문이며 그 결과 이러한 심부가스를 경제적으로 개발하기 위하여는 많은 기술적 도전을 극복하여야 한다. 본 논문에서는 이러한 낮은 성공률을 가지는 심부 가스의 개발 성공률을 증가시키기 위하여 심부 가스가 존재하는 지역의 지질학적 부존 환경 및 조성상의 특성과 생산시 소요되는 생산비용을 심도에 따라 분석하고 생산에 수반되는 기술적 문제점들을 정리하였으며 마지막으로 향후 요구되는 연구 분야들을 제시하였다. 또한 참고로 현재 심부 가스의 경우 미국이 연구 개발 측면에서 가장 활발한 활동을 전개하고 있으며 그 결과 다수의 신뢰성 있는 자료들을 확보하고 있으므로 본 논문은 USGS와 Gas Research Institute(GRI)에서 제시한 자료에 근거하였다.

• Communications for Statistical Applications and Methods
• /
• 제15권5호
• /
• pp.737-752
• /
• 2008

오차에 대한 분석은 18세기 천문학과 측지학에서 시작된 뒤, 19세기 초 가우스와 라플라스에 의해 정규분포 및 최소제곱법과 결합되면서 오차이론이라고 불리기 시작하였다. 19세기 중엽 벨기에의 케틀레는 자연과학의 관측결과를 분석하는데 쓰이던 오차이론을 사회 데이터에 적용함으로써 사회 연구를 보다 더 과학적인 연구로 만들어보려 하였다. 그는 사회데이터에서 개인의 특수성을 배제하고 집단의 보편적인 사실만을 나타내는 '평균적인 사람'이라는 개념을 만들었다. 또 그는 비슷한 조건에 있는 여러 사람을 측정한 결과는 단일한 대상을 반복측정한 결과와 마찬가지라고 보고, 천문학의 오차이론을 사회데이터에 적용하였다. 이 논문에서는 오차와 정규분포가 사회 연구에 도입되면서 새로이 나타난 개인과 집단의 관계를 비롯하여 오차이론에 대한 반대 의견들, 오차를 대신하여 나타난 용어 등을 중심으로 19세기 중반에 통계학의 영역이 확대되는 과정을 살펴보았다.

• Journal of Biosystems Engineering
• /
• 제3권1호
• /
• pp.64-76
• /
• 1978

A dimensional supply of petroleum fuels and increased competition for petroleum products has made the conservation of energy in grain drying an important cost and management factor. Research on solar grain drying is directed toward utilization of a renewable energy source as an alternative to petroleum fuels for drying. There are many technical and economic problems in accepting and adopting solor energy as a new energy source for grain drying. The purpose of this study are to assess the state of the art of solar grain drying and to find out the problems by reviewing literatures available. The results obtained may be summarized as follows; 1.It may be considered that the weather conditions in October of Korea was satisfactory for the forced natural air and solar heated air drying. 2. Solar energy is considered more applicable to low-temperature, In-storage drying systems than to high-temperature, high-speed drying systems. In-storage drying systems require low levels of heat input. The costs of collector systems to provide low temperature are considerably cheaper than for high-temperature systems. 3. Tubular type collector made of polyvinyle film seems to be the most practical at this stage of development and black-painted bare-plate collectors mounted on the outside of a typical, round, low-temperature drying bin can supply an appreciable amount of the energy efficiently needed for low-temperature grain drying at a lower cost. 4. All of the grains in solar drying tests was successfully dried up to safe storaged moisture levels without significant spoilage. Drying rates with solar system were faster than natural air drying systems, and usually a little slower than similar low-temperature electric drying systems. 5. Final grain moisture levels were lower in solar tests than in natural air tests, and generally higher than in tests with continuous heated air. 6. Savings of energy by use of solar collectors ranged from 23% to 55%, compared to the natural and electric ileated air drying systems. However, total drying cost effectiteness tvas not significant. Therefore, it is desirable that solar grain dry-ing sIFstems tvhich could be suitable for multiple heating purposes on farms shouldbe developed. 7. Supplemental heat with solar radiation did little to reduce air flow requirementsbut refuced drying time and increased the p\ulcornerobability of successful drying duringdrying poriod.

• 한국학교수학회논문집
• /
• 제5권1호
• /
• pp.111-122
• /
• 2002

The purpose of this study was to examine high school second graders' understanding of the basic nature of logarithm, the major type of error they made about logarithmic function and the cause of such an error, and to seek ways to instruct it better. For that purpose, three research questions were posed: 1. Investigate how much high school students in their second year comprehend the nature of logarithm. 2. Analyze what type of error they make about logarithmic function. 3. Analyze the cause of their error according to the selected error models and how it could be taught more efficiently. The findings of this study were as below: First, the natural science students had a better understanding of the basic nature of logarithm than the academic students. What produced the widest gap between the two groups' understanding was applying the nature of logarithm to the given problems, and what caused the smallest gap was the definition of logarithm and the condition of base. Second, the academic students had a poorer understanding of the basic nature of logarithmic function graph and of applying the nature of logarithm to the given problems. Third, the natural science students didn't comprehend well the basic nature of logarithmic function graph, the nature of characteristics and mantissa. Fourth, for all the students from academic and natural science courses, the most common errors were caused by the poor understanding of theorem or nature of the ［E4] model. Fifth, the academic students made more frequent errors due to the unfamiliar signs of the ［El］ model, the imperfect understanding of theorem or nature of the ［E4］ model, and the technical part of the ［E6］ model. Sixth, the natural science students made more frequent errors because of the improper problem interpretation of the ［E2］ model and the logically improper inference of the ［E3］ model.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제58권1호
• /
• pp.1-20
• /
• 2019

As the importance of algebraic thinking in elementary school has been emphasized, the links between fraction knowledge and algebraic thinking have been highlighted. In this study, we analyzed the solution methods and characteristics of thinking by fifth graders who have not yet learned fraction division when they solved 'reverse fraction problems' (Pearn & Stephens, 2018). In doing so, the contexts of problems were extended from the prior study to include the following cases: (a) the partial quantity with a natural number is discrete or continuous; (b) the partial quantity is a natural number or a fraction; (c) the equivalent fraction of partial quantity is a proper fraction or an improper fraction; and (d) the diagram is presented or not. The analytic framework was elaborated to look closely at students' solution methods according to the different contexts of problems. The most prevalent method students used was a multiplicative method by which students divided the partial quantity by the numerator of the given fraction and then multiplied it by the denominator. Some students were able to use a multiplicative method regardless of the given problem contexts. The results of this study showed that students were able to understand equivalence, transform using equivalence, and use generalizable methods. This study is expected to highlight the close connection between fraction and algebraic thinking, and to suggest implications for developing algebraic thinking when to deal with fraction operations.

• 한국염색가공학회지
• /
• 제33권4호
• /
• pp.202-209
• /
• 2021

Natural dyes are more expensive than synthetic dyes and the dyeing process, which is mainly immersion of dye, is complicated. For this reason, relatively small-scale production methods were predominant. However, awareness and interest in environmental sustainability is rising globally, and the use of synthetic dyes causes various environmental problems such as wastewater and CO₂ emission, so the consumption of natural dyes is increasing. In addition, interest in digital textile printing, an eco-friendly dyeing method that can produce products of various designs and uses less water, is growing. In this study, natural indigo dye (Indigofera tinctoria) was used as a raw material for Digital Textile Printing ink, and ¹⁴C (Biocarbon) present in it was measured to confirm whether it was derived from natural ingredients. The performance was confirmed by testing the pH, viscosity, electrical conductivity, surface tension, and particle size analysis of natural indigo ink. In addition, the performance of natural indigo DTP ink and printing fabric was evaluated by inspecting the change in color fastness and corresponding index substances before and after digital printing with natural indigo DTP ink on textiles. Through this, the possibility of commercialization of DTP ink and printing fabric using natural indigo was confirmed.

• Journal of Microbiology
• /
• 제37권2호
• /
• pp.66-72
• /
• 1999

Mycolic acid-containing actinomycetes associated with extensive foaming in the aeration basin of the activated sludge process were isolated and analyzed by phenotypical, chemotaxonomical and phylogenetic methods. Whole cell sugar patterns of two isolates were pattern A. The nearly complete sequences of the 16S rRNA genes (rDNAs) of the isolates were determined and compared by using several tree-making algorithms. With polyphasic methods, strain SCNU1 was identified as Gordona sputi, and strain SCNU5 assigned to the genus Tsukamurella. The presence of opportunistic pathogens of chronic lung infections within foams can cause public health problems and render waste-treatment processes inefficient.

• 한국실내디자인학회:학술대회논문집
• /
• 한국실내디자인학회 2004년도 춘계학술발표대회 논문집
• /
• pp.136-140
• /
• 2004

This study starts from the premise that future elementary school should be designed based on ecological approach. In order to restore the emotionality of children, school should provide and protect our natural environment by greening and energy saving. The research was conducted in Osaka and Busan to analyze the present condition of elementary schools in terms of ecology. The shared spaces such as halls, corridors, stairs and rest areas of fourteen schools were chosen and analyzed by the design analysis list. The list included the guidelines including greening, lighting, heating and cooling, ventilation and use of materials. The results showed that Korean schools require void space for more natural lighting, ventilation and insulation, while Japanese schools have problems in use of environmentally friendly materials, natural lighting and interior greening. This study reveals that ecological approach including greening and natural lighting should be considered in future elementary school design to make the school environment more agreeable and economical.

• Structural Engineering and Mechanics
• /
• 제17권3_4호
• /
• pp.467-482
• /
• 2004

One of the uncertain damage parameters to jeopardize the safety of existing PSC bridges is the loss of the prestress force. A substantial prestress-loss can lead to severe problems in the serviceability and safety of the PSC bridges. In this paper, a nondestructive method to detect prestress-loss in beam-type PSC bridges using a few natural frequencies is presented. An analytical model is formulated to estimate changes in natural frequencies of the PSC bridges under various prestress forces. Also, an inverse-solution algorithm is proposed to detect the prestress-loss by measuring the changes in natural frequencies. The feasibility of the proposed approach is evaluated using PSC beams for which a few natural frequencies were experimentally measured for a set of prestress-loss cases. Numerical models of two-span continuous PSC beams are also examined to verify that the proposed algorithm works on more complicated cases.