• 대한건축학회논문집:계획계
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• 제33권12호
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• pp.73-83
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• 2017

Due to the changes in the contemporary society, small-scale traditional markets have declined and lost their functions as the center of neighborhood commercial and cultural affairs. While most traditional markets are deteriorating, there exist rare cases of neighborhood small-scale traditional markets that continuously maintain their vitality and popularity. This paper examines urban spatial characteristics of those markets. As for the cases, this paper inventoried eighteen such markets in Gwanak-gu, Seoul. The research methods include literature reviews, on-site investigation of total 18 such markets, and participant observations. The findings of this paper are as follows: There are distinctive differences in the urban-spatial characteristics of physical environmental factors between the revitalized markets and declining markets. In terms of neighborhood and commercial environment, the franchised super-markets are not necessarily in competition with small-scale traditional markets. The former often has symbiotic relationship the latter, if the small scale traditional markets are strategically located in between residential areas and subway stations, providing active pedestrian networks. There are many outdoor display stands in the revitalized markets, while the declining markets rarely have them. The market improvement projects such as transforming the open space into arcade space, hardly have effects on revitalization of the small-scale traditional markets.

• 한국통신학회논문지
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• 제42권4호
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• pp.915-922
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• 2017

최근 지속적인 전력 수요 증가와 이에 따른 사회적 비용 및 갈등 해결을 위한 방안으로 수요자원 거래시장(Demand Response Market)의 활성화가 크게 대두되고 있다. 국내의 경우 2014년부터 수요자원 거래시장을 운영 중이나 대규모 수요자원 거래에 집중하고 있다. 하지만, 전력 소비 비중의 증가, 큰 감축 유동성, 항상 활용 가능, 사회 인식 개선 등의 면에서 소규모 전력 소비자의 시장 참여는 성공적인 수요자원 거래시장 운영의 핵심적 요소로 볼 수 있다. 이 논문은 2016년 여름 스마트폰 어플리케이션을 활용하여 5,000명 이상의 소규모 전력 소비자를 대상으로 한 인센티브 기반(incentive-based) 수요반응(Demand Response) 프로그램의 실제 시범운영 결과를 분석하고 그 효과를 검증하며, 이를 통하여 소규모 전력 소비자 대상 수요자원 거래시장의 가능성을 제시한다.

• 수산경영론집
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• 제40권1호
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• pp.1-26
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• 2009

The aquaculture management considers the maintenance of households lifehood more than profit maximization. As aquaculture industry has developed enterprise farms appeared, and the small and the large scale farms coexist. The features of coexistence could be summarized as followings. First of all, the large scale farms show the higher net profit while the small scale farms show the higher profit per 1ha and the earning rate. Secondly, in the case of over 2ha, the earning rate is stable in spite of the scale expansion. Moreover, in processing method, dried seaweed occupy the biggest proportion in the small scale farms while the raw seaweed occupy the biggest proportion in the large scale farms. Lastly, the scale of farms becomes larger, the participation rate of household labor rises. This thesis analyses the efficiency of Korean seaweed farms in the way of DEA model and suggests the improvements for the efficiency management. The mean technical, pure technical and scale efficiencies were measured to be 0.88, 0.96 and 0.91, respectively. Among the 20 farms included in the analysis, 10 were technically efficient and 12 were scale efficient. In conclusion, it is shown that the aquaculture farms has been becoming the form of coexistence. This appearance results in the effort for reducing the cost in the small scale farms and in profit maximization in the large scale farms. On the other hand, middle scale farms is inefficient compared with the small or large scale farms. Therefore, in order to achieve the efficiency, it is necessary to accomplish economy of scale by extending farm size or to cut expenses by reducing farm area. In other word, the efforts for achieving the efficiency is required in a different direction in spite of the same scale.

• 천문학회지
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• 제29권spc1호
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• pp.155-158
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• 1996

Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to the winding up of a primordial cosmological field or due to amplification of a small seed field by a turbulent galactic dynamo. Both options have difficulties: There is no known battery mechanism for producing the required primordial field. Equally the turbulent dynamo may self destruct before being able to produce the large scale field, due to excess generation of small scale power. The current status of these difficulties is discussed. The resolution could depend on the nature of the saturated field produced by the small scale dynamo. We argue that the small scale fields do not fill most of the volume of the fluid and instead concentrate into intermittent ropes, with their peak value of order equipartition fields, and radii much smaller than their lengths. In this case these fields neither drain significant energy from the turbulence nor convert eddy motion of the turbulence on the outer scale to wave like motion. This preserves the diffusive effects needed for the large scale dynamo operation.

• 한국지진공학회논문집
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• 제7권6호
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• pp.49-57
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• 2003

지진하중에 대한 구조물의 동적 거동과 내진성능을 평가하기 위하여 유사동적실험기법이 흔히 사용되고 있으나, 실험장비의 제약과 구조물의 규모 등으로 대부분 축소모형실험에 의존하고 있다. 그러나 일반적인 상사법칙은 탄성범위에서 유도된 것으로 지진거동과 같은 비탄성 거동을 예측하는 경우에는 한계가 있기 때문에 축소모형의 실험결과를 원형 구조물에 직접 적용하는 것은 많은 주의가 필요하다. 본 연구에서는 원형구조물과 축소모형에 대한 철골모형을 실험 대상으로 하여 실제 축소모형 실험결과로부터 원형구조물의 거동을 예측하는 경우의 문제점을 확인하고, 그 해결방법을 모색하고자 한다. 실제로 축소모형실험에서는 원형구조물의 경계조건을 정확히 재현하기 어려우며, 축소모형의 제작과정과 실험과정에서의 모든 오차가 강성의 변화로 반영되어 나타난다. 따라서 본 연구에서는 기하학적 상사율과 축소모형의 변화된 강성비를 함께 고려한 수정된 상사법칙을 제안하였으며, 수정된 상사법칙이 적용된 축소모형에 대하여 유사동적실험을 수행하여 지진응답결과를 원형구조물의 결과와 비교하였다. 축소모형에 대한 유사동적실험결과로부터 제안된 상사법칙을 적용함으로써 원형구조물의 지진응답 재현이 효과적임을 입증하였다.

• 한국습지학회지
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• 제18권3호
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• pp.267-274
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• 2016

농촌 지역 하수도 보급은 하천, 호소 및 습지와 같은 수계 수질 보호를 위해서 반드시 필요하다. 또한 안정적인 소규모 하수처리장 운영을 위해서는 유입 유량과 농도의 변화가 큰 소규모 하수도 특성을 고려해야 한다. 본 연구에서는 봉화군 18개의 소규모 하수처리장 운전 결과를 통해 유입유량비 (유입 유량 / 설계 유량) 특성, 소규모 하수처리장 처리 효율에 미치는 영향과 적정 유입유량비 산정에 관한 연구를 수행하였다. 분석 결과 유입유량비는 여름철에 가장 높은 것으로 나타난 반면, 유입 하수 농도는 가을철과 겨울철에 높은 것으로 나타났다. 유입유량비가 증가할수록 처리 효율이 증가하는 경향을 보였으며, 영양염류 처리 효율이 유기물과 부유물질 처리 효율에 비해 민감한 영향을 받는 것으로 나타났다. 안정적인 소규모 하수처리장 처리 효율을 위해서는 유입유량비 0.8 이상을 유지해야 할 것으로 판단된다.

• Smart Structures and Systems
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• 제21권3호
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• pp.279-286
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• 2018

The free longitudinal vibration of a circular truncated nanocone is investigated based on the nonlocal elasticity theory. Exact analytical formulations for tapered nanostructures are derived and the nonlinear differential governing equation of motion is developed. The nonlocal small scale effect unavailable in classical continuum theory is addressed to reveal the long-range interaction of atoms implicated in nonlocal constitutive relation. Unlike most previous studies applying the truncation method to the infinite higher-order differential equation, this paper aims to consider all higher-order terms to show the overall nonlocality. The explicit solution of nonlocal stress for longitudinal deformation is determined and it is an infinite series incorporating the classical stress derived in classical mechanics of materials and the infinite higher-order derivative of longitudinal displacement. Subsequently, the first three modes natural frequencies are calculated numerically and the significant effects of nonlocal small scale and vertex angle on natural frequencies are examined. The coupling phenomenon of natural frequency is observed and it is induced by the combined effects of nonlocal small scale and vertex angle. The critical value of nonlocal small scale is defined, and after that a new proposal for determining the range of nonlocal small scale is put forward since the principle of choosing the nonlocal small scale is still unclear at present. Additionally, two different types of nonlocal effects, namely the nonlocal stiffness weakening and strengthening, reversed phenomena existing in nanostructures are observed and verified. Hence the opposite nonlocal effects are resolved again clearly. The nano-engineers dealing with a circular truncated nanocone-based sensors and oscillators may benefit from the present work.

• 대한건축학회논문집:구조계
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• 제35권10호
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• pp.217-223
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• 2019

The purpose of this study was to measure the indoor air quality of small-scale apartments and then proposed a method to improve the indoor air quality of the small-scale apartments by comparing with the result of indoor air quality in the Clean-Healthy House. In case of formaldehyde, a highly volatile organic compound, the concentrations of indoor measured both in small-scale apartments and the Clean Healthy houses did not exceed- the guideline of Korea. The guideline of Korea for acetaldehyde was not available, so the guidelines of Japan and the World Health Organization were used to measure the concentration of acetaldehyde. The study results demonstrated that three out of seven small-scale apartments investigated exceeded the guideline of Japan; and the preliminary research on the Clean-Health Houses was low at about 30-60% of the guideline of Japan. The result of the VOCs measurement showed that toluene, ethylbenzene, and styrene in some small-scale apartments exceeded the guideline of Korea. However, the Clean-Healthy Houses in the previous studies did not exceed the guideline of Korea with regard to all the pollutants. Therefore, this study suggests the application of the construction standards of the Clean-Healthy house in order to improve the indoor air quality of small-scale apartments. In addition, the current study anticipates that improvement of the indoor air quality in the residential environments should be universally applied, not limited to the type and size of the residence.

• International Journal of Railway
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• 제4권2호
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• pp.50-55
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• 2011

The dynamic stability of railway vehicle has long been one of the important issues in railway safety. The dynamic simulator has been used as a tool for investigating the dynamic stability of railway vehicles and wheel/rail interfaces. In particular, small scale simulators have been widely used in laboratory studies instead of full scale roller rigs which can be quite costly and rather inconvenient for testing out the effect of diverse design parameters. But techniques for design of a small scale simulator for the fundamental study about the dynamic characteristics of the wheel-rail systems and the bogie systems have not been well developed in Korea. Therefore, a research on the development of a small scale simulator for investigating bogie dynamics needs to be undertaken. The present paper investigates design of a small-scaled derailment simulator and the design of a small scale bogie. The simulator developed can be used to investigate the effect of diverse parameters such as attack angle, wheelbase and cant on dynamic behavior of the bogie and key dynamic performance parameters such as derailment coefficient and critical speed.

• 대한화학회지
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• 제49권2호
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• pp.208-214
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• 2005