• 대기
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• 제19권2호
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• pp.155-168
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• 2009

Characteristics of seasonal mean diurnal temperature range (DTR) and their causes over South Korea are investigated using the 60 stations data of Korea Meteorological Administration from 1976 to 2005. In general, the seasonal mean DTR is greatest during spring (in inland area) and least during summer (urban and coastal area). The spatial and seasonal variations of DTR are closely linked with the land surface conditions (especially vegetation activity and soil moisture) and atmospheric conditions (cloud amount, precipitation, local circulation). The seasonal mean DTR shows a decreasing trend at the major urban areas and at the north-eastern part of South Korea. Whereas, it shows an increasing trend at the central area of the southern part. Decreasing and increasing trends of DTR are more significant during summer and fall, and during spring and winter. The decrease (increase) of DTR is mainly caused by the stronger increase of daily minimum (maximum) temperature than daily maximum (minimum) temperature. The negative effects of precipitation and cloud amount on the DTR are greater during spring and at the inland area than during winter and at the coastal area. And the effect of daytime precipitation on the DTR is greater than that of nighttime precipitation.

• 한국실내디자인학회논문집
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• 제29호
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• pp.153-162
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• 2001

This study suggests the basic data required in setting up the standard for the architectural planning of Korean senior center by analyzing the standard and current situation of a senior center in Japan that has the welfare facility system similar to that of Korea and understanding its architectural characteristics. 1) Basic spaces that constitute the senior center in Japan are meeting room, lecture room, library, multipurpose meeting room, conference room, game-recreation room, kitchen, lounge, locker room and office. ADL, kitchen, relaxing room, private bathroom, and special bathroom are needed for adult day care as establishments as an annex and work room is also required for Job training. 2) The area of a senior center is calculated in consideration of its space organization that are required as basic. For the type "A", minimum area of 1,256.42 $m^2$2 and maximum area of 2,050.56$m^2$ and for the type "B", minimum area of 812000$m^2$ and maximum area of 1,604.14$m^2$ are suggested as optimum areas. 3) The circulation planning is presented by the connected between the space organization as well as the circulation system in day care center.

• Fisheries and Aquatic Sciences
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• 제27권1호
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• pp.1-6
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• 2024

In this study, the swimming behavior of a small box jellyfish (Carybdea brevipedalia), which consists of inhaling external seawater and expelling it through its mouth to generate forward thrust, was characterized using particle image velocimetry (PIV). The flow rate and structure during the suction and discharge process were quantitatively analyzed. During swimming, there was a change in the ratio of the internal area during inhalation and expulsion. Specifically, there was a 1.10-fold difference between the maximum area after inhalation and the minimum area after discharge. The maximum distance traveled after discharge was inversely proportional to the size of the inner area, with a 2.48-fold difference in the minimum distance traveled after suction. Depending on the propulsion stage, the inner area decreased and then increased in proportion to the moving distance and speed. The moving distance of the small box jellyfish was measured for each period. The speed for each swimming stage increased and then decreased at intervals of 0.15 to 0.2 seconds, and the suction and discharge cycle period was measured at approximately 0.5 seconds. Collectively, our findings provide a methodological basis for studying the swimming behavior of small and highly active trailing jet jellyfish, as well as the biological mechanisms that determine this behavior.

• 한국농림기상학회지
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• 제24권4호
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• pp.244-255
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• 2022

본 연구는 국내의 ASOS 및 AWS와 AMOS 관측 값을 사용하여 1km 고해상도의 산악기상 격자 값을 추정하고 평가하였다. 해발고도 200m이상을 산악지역으로 정의하고 ASOS, AWS, AMOS 기상관측소를 산악기상이 반영된 기상데이터와 산악기상이 반영되지 않는 기상데이터로 나누었다. 2013년에서 2020년까지 산악기상 데이터를 적용하고 편의보정기법(bias correction method)방법을 통하여 산악기상 적용에 따른 보정계수를 산출하고 적용하여 보정계수 및 산악기상 데이터가 반영된 고해상도 산악기상기온 격자 데이터를 생성하였다. 추정된 산악기상기온 격자데이터는 검증지점의 기상 기온 실측 값과 비교하여 평가하였다. 산악기상 데이터 반영 및 보정계수가 반영된 산악기상 고해상도 격자 기온은 산악기상이 반영되지 않는 격자기온보다 RMSE가 34%(평균기온), 50%(최저기온), 31%(최고기온)가 감소하였다. 이는 산악기상 정보기반과 산악기상 보정계수를 적용이 국내 산악기상고해상도 격자 생성에 있어서 정확도를 크게 개선시킬 수 있음을 시사하였다. 이러한 1km 고해상도의 기온 격자데이터는 추후 기후변화에 대한 산림생태계 변화 및 산림재해 모델의 검증을 위한 데이터로 매우 유용하게 활용될 수 있을 것이라 사료된다.

• 대한전자공학회논문지
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• 제25권5호
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• pp.509-521
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• 1988

In the designs of integrated circuits, the buffer circuits used for driving a large capacitive load from minimum-structured logic circuit outputs have important effects upon system throughputs. Therefore it is important to optimize the buffer circuits. In this paper, the principle of designing CMOS buffer circuits which have the minimum delay and drive the given capacitive load is discussed. That is, the effects of load capacitance upon rise time, fall time, and delay of the CMOS inverter and the effects of parasitic capacitances are finely analysed to calculate the requested minimum-delay CMOS buffer condition. This is different from the method by C.A. Mead et. al.[2.3.4.]which deals with passive-load-nMOS buffers. Large channel width MOS transistor stages are necessary to drive a large capacitive load. The effects of polysilicon gate resistances of such large stages upon delay are also analysed.And, the area of buffer circuits designed by the proposed method is smaller than that of buffer circuits designed by C.A. Mead's method.

• 한국자동차공학회논문집
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• 제1권1호
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• pp.59-65
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• 1993

In a spark ignition engine, in order to make research on flame propagation, attentive concentration should be paid on initial combustion stage about the formation and development of flame. In addition, the initial stage of combustion governs overall combustion period in a spark ignition engine. With the increase of the size of flame kernel, it could reach initial flame stage easily, and the mixture could proceed to the combustion of stabilized state. Therefore, we must study the theoretical calculation of minimum flame kernel radius which effects on the formation and development of kernel. To calculate the minimum flame kernel radius, we must know the thermal conductivity, flame temperature, laminar burning velocity and etc. The thermal conductivity is derived from the molecular kinetic theory, the flame temperature from the chemical reaction equations and the laminar burning velocity from the D.K.Kuehl's formula. In order to estimate the correctness of the theoretically calculated minimum flame kernel radius, the researcheres compared it with the RMaly's experimental values.

• 대한전자공학회논문지TC
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• 제44권8호
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• pp.62-67
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• 2007

센서네트워크 중에는 센서노드들이 넓은 지역에 걸쳐 정해진 위치에 산재되어야 하는 경우가 있다. 이런 경우 센서노드들을 interconnect하기 위한 최소개수의 연결노드들을 추가하는 문제가 대두되며, 이는 The Minimum number of Steiner Points라는 추상화된 문제로 귀결된다. 이 문제는 NP-hard 문제이므로, 본 논문에서는 문제가 내포하는 기하학적인 성질을 이용하여 연결노드의 최소개수에 근접하는 방안을 제시한다. 센서네트워크에서 노드의 개수를 줄임으로써 네트워크 내부에서 오가는 메시지의 교환량이 대폭 감소하게 된다.

• 정보처리학회논문지A
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• 제18A권2호
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• pp.69-74
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• 2011

그래프 G의 최소 dominating set 문제는 G의 dominating set들 중 가장 작은 크기의 dominating set을 찾는 문제이며, NP-complete class에 속해 polynomial time안에 해결할 수 없는 문제로 잘 알려져 있다. 그러나, heuristic한 방법 혹은 approximation 방법을 이용해 특정한 분야에 적용이 가능하다. 본 논문에서는 세 개의 서로 다른 simulated annealing 알고리즘을 제시하여, 이들 알고리즘을 DIMACS에서 제시한 그래프들에 적용한 경우 효율성 증가가 이루어지는 것을 실험적으로 보이고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.819-824
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• 1989

This paper proposes a new method for the discovery and design of an optimal heat exchanger network. The method is based upon the concept of pinch, a problem reduction technique and the heuristics developed in this work. It generates subproblems in a logical way and solves the subproblems by the heuristics to synthesize an optimal network structure. It is thought that the heuristics can preserve the minimum utility consumption, the minimum number of heat exchanger units, and the minimum number of stream splittings needed for a given problem. The minimum heat exchanger area for the optimal network can then be obtained by adjusting the temperatures associate with the heat exchanger in the optimal network structure. The method is applied to the problems appeared in the literatures. The results show the reductions in the number of heat exchanger units for some problems.

• 한국ITS학회 논문지
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• 제12권5호
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• pp.36-45
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• 2013

본 연구에서는 최단경로를 반드시 찾아내는 Dijkstra 알고리즘의 장점과 최단경로 탐색 소요시간을 단축시키는 $A^*$알고리즘의 장점을 결합시킨 새로운 최단경로 탐색 알고리즘을 개발하였다. 개발한 알고리즘은 탐색노드에서 목적노드까지의 최소 기대 부하량을 산출하고 이 값을 이용하여 계속 탐색 또는 이전 탐색노드로의 후퇴를 결정한다. 최소 기대 부하량은 목적노드가지의 직선거리에 최소 가로 부하량 원단위를 곱하여 산출하는데, 적용하는 네트워크에서는 그 값 이하의 부하량이 존재할 수 없는 값이다. 개발한 알고리즘을 실제 네트워크에 적용하여 최단경로를 탐색해 본 결과, 어느 정도의 탐색 소요시간은 필요로 하나, 완벽하게 최단경로를 구축하는 것으로 나타났다. 개발한 알고리즘은 광역의 네트워크를 이용하는 차량 경로 안내시스템 등에서 효과를 가질 것으로 판단한다.