• 동력기계공학회지
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• 제11권3호
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• pp.29-34
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• 2007

Existent researches about indoor thermal environment have been focused on to seek human's comfort in daytime. Also researches about thermal comfort during the sleeping time that is important for resting and recharging to modern people have been seldom existed. At present, as global warming phenomenon is being continued, most people are going through inconvenience by sultriness during the sleeping hours in sweltering summer night. Therefore we need another control method of an air conditioner to keep human's thermal comfort. Ambient temperature is a common factor of the environment, but analysis of its effect on human body physiology is still unknown. The effect of ambient temperature on human sleep has been increasingly studied in the last decade. This research investigated about optimal indoor temperature to maintain proper skin temperature and comfortable sleep when indoor air is cooled by an air conditioner in sweltering summer night.

• 한국양식학회지
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• 제9권1호
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• pp.65-71
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• 1996

PVC 파판에서 초기전복치패의 먹이생물인 저서미소조류의 변화를 추정하기 위해 1984년 1월부터 12월까지 France Bourneuf만의 굴 양성지에 파판을 수하하여 파판에 부착 발생된 저소미소조류의 엽록소 a와 갈색소를 분석하였다. 저서미소조류의 생체량을 엽록소의 양으로 추정하고, 생리상태를 갈색소의 백분율로 나타낼때 생체량은 제절에따라 겨울에는 파판의 수하시간에 따라 비례하여 증가하였으나, 고수온기인 여름에는 저서미소조류의 군집이 빠르게 노쇠되어 매 2주마다 최대치를 나타내는 양상을 보였다. 갈색소의 백분율은 봄과 가을에 낮은 비율을 나타내었으나, 여름 고수온기에는 군집의 빠른 노쇠로 인하여 백분율은 최대치를 나타내어 군집의 활성이 저하되었으며, 생체량과 갈색소의 백분율을 고려할 때 5, 6월과 9, 10월에 전복의 산란이 이루어지는 것은 저서미소조류를 먹이로 하는 초기부착치패에게 영양적으로 종은 균형을 이루게 한다.

• Ocean and Polar Research
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• 제29권2호
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• pp.113-121
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• 2007

The sound wave in the sea propagates under the effect of water depth, sound speed structure, sea surface roughness, bottom roughness, and acoustic properties of bottom sediment. In shallow water, the bottom sediments are distributed very variously with place and the sound speed structure varying with time and space. In order to investigate the seasonal propagation characteristics of low-frequency sound wave in the Yellow Sea, propagation experiments were conducted along a track in the middle part of the Yellow Sea in spring, summer, and autumn. In this paper we consider seasonal variations of the sound speed profile and propagation loss based on the measurement results. Also we quantitatively investigate variation of bottom loss by dividing the propagation loss into three components: spreading loss, absorption loss, and bottom loss. As a result, the propagation losses measured in summer were larger than the losses in spring and autumn, and the propagation losses measured in autumn were smaller than the losses in spring. The spreading loss and the absorption loss did not show seasonal variations, but the bottom loss showed seasonal variations. So it was thought that the seasonal variation of the propagation loss was due to the seasonal change of the bottom loss and the seasonal variation of the bottom loss was due to the change of the sound speed profile by season.

• 한국대기환경학회지
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• 제10권4호
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• pp.224-232
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• 1994

A new neural network model has been developed to predict short-term air pollution concentration. In addition, a multiple regression model widely used in statistical analysis was tested. These models were applied for prediction of daily maximum ozone concentration in Seoul during the summer season of 1991. The time periods between May and September 1989 and 1990 were utilized to train set of learning patterns in neural network model, and to estimate multiple regression model. To evaluate the results of the different models, several Performance indices were used. The results indicated that the multiple regression model tended to underpredict the daily maximum ozone concentration with small r$^{2}$(0.38). Also, large errors were found in this model; 21.1 ppb for RMSE, 0.324 for NMSE, and -0.164 for MRE. On the other hand, the results obtained from the neural network model were very promising. Thus, we can know that this model has a prominent efficiency in the adaptive control for the non-linear multi- variable systems such as photochemical oxidants. Also, when the recent new information was added in the neural network model, prediction accuracy was increased. From the new model, the values of RMSE, NMSE and r$^{2}$ were 13.2ppb, 0.089, 0.003 and 0.55 respectively.

• 한국생활과학회지
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• 제15권2호
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• pp.275-281
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• 2006

The purpose of this study is to investigate hand and sensibility of PET treated by Ultra-Violet (UV). The 4-channel PET knit fabric was treated by a self-made UV instrument in 5cm distance with different time frames-0min, 30min, and 90min. For hand evaluation, mechanical properties were measured by the KES-FB system. The environmental condition was controlled at 29$^{\circ}C$, 75% (R.H.)-summer standard climate. Twenty female students evaluated 'roughness', 'smoothness', 'wetness', 'stiffness', 'coolness', 'touch', 'preference', and 'comfort'. The outcomes of the experiment are as follows: The surface roughness of mechanical properties showed significant differences and the value of PET irradiated by UV for 90min was highest. The order of primary hand value such as NUMERI and FUKURAMI was in a following order-Untreated > 30min treated > 90min treated. Total hand value showed that PET irradiated by UV for 90min was appropriate for using summer fabric. The results of subjective sensibility were that the untreated and 30min treated PET were recognized as similar and had a good evaluation on 'comfort', 'preference' and 'the sense of touch'. This consequence disagreed with total hand value, because it was considered that subjects' hand sensibility was dependent on the feel of smoothness.

• 한국멀티미디어학회논문지
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• 제23권2호
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• pp.155-165
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• 2020

In this paper, we propose a smart thermostat temperature set-point control method based on machine learning and rule engine, which controls thermostat's temperature set-point so that it can achieve energy savings as much as possible without sacrifice of occupants' comfort while users' preference usage pattern is respected. First, the proposed method periodically mines data about how user likes for heating (winter)/cooling (summer) his or her home by learning his or her usage pattern of setting temperature set-point of the thermostat during the past several weeks. Then, from this learning, the proposed method establishes a weekly schedule about temperature setting. Next, by referring to thermal comfort chart by ASHRAE, it makes rules about how to adjust temperature set-points as much as low (winter) or high (summer) while the newly adjusted temperature set-point satisfies thermal comfort zone for predicted humidity. In order to make rules work on time or events, we adopt rule engine so that it can achieve energy savings properly without sacrifice of occupants' comfort. Through experiments, it is shown that the proposed smart thermostat temperature set-point control method can achieve better energy savings while keeping human comfort compared to other conventional thermostat.

• 생태와환경
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• 제38권spc호
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• pp.39-43
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• 2005

The dynamics of water quality with the storm events were analyzed in a small reservoir for irrigation, Lake Wangkung. Water quality of the inflowing stream fluctuated seasonally with the variation of flow rate. Thermal stratification was consistent from April to October below 2 m depths and anoxic layer was developed below 2 m depth in summer. The unique feature of temperature showed that thermal stratification was disrupted by a heavy rain event during monsoon, but hypolimnetic hypoxia were reestablished after a few days. Phosphorus and nitrogen increased immediately following storm events. The marked increase may be due to the input of P-rich storm runoff from the watershed. Internal phosphorus loading can be one of the explanations for TP increases in summer. When there was a storm, total populations of phytoplankton and zooplankton was reduced immediately following the storm, indicating possible flushing of algae and zooplankton. After a lag period of low-density the plankton population bloomed to a peak again within five days after the storm. Turbid water in lake became clear again which coincided with the time of the phytoplankton buildup. The results demonstrate that water quality is regulated greatly by rainfall intensity in Lake Wangkung.

• 한국해양학회지
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• 제17권2호
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• pp.74-82
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• 1982

1968-1980年의 韓.日共同海洋調査點中 韓國側 63個定點의 海洋調査資料를 使用하여 月別 水溫 및 분의 變動係數를 分析 硏究한 缺課의 要約은 다음과 같다. 變動係數는 水溫과 분의 前線域이나 혹은 躍層形成海域에서 크게 나타났다. 水溫의 變動係數는 각 水塊의 勞力이 가장 强한 時期에 最大値를 나타냈다(對馬 暖流와 黃海暖流域의 夏季 中層에서, 南海岸沿岸水 및 西海南部域의 冬季의 全層 에서 最大). 鹽分의 變動係數는 東支那海 低鹽水의 影響을 많이 받는 夏季에 暖流系水의 表層水에서 크게 나타나며, 沿岸水 및 西海南部域에서는 暖流系水値의 1/2정도였다.

• 한국국방경영분석학회지
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• 제30권2호
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• pp.50-62
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• 2004

Every year, about 250,000 new recruits enter the military under the R.O.K military draft system. When the fresh soldier groups arrived at the Recruit Training Center, their supplies are distributed before they get basic military training. The supplies are divided by season, summer and winter. There are 14 class of summer items and 20 class of winter items, and the each class has about a few kinds of items. Totally, there are the hundreds kinds of supplies and the supplies distribution system is manually operated. However, in the current system, many problems such as spending a lot of time, manpower and high change rate due to the inaccurate distribution have been raised. This paper suggests the automated supplies distribution system to solve the above problems. We choose the appropriate facilities in the system by using the AHP(Analytic Hierarchy Process) and analyse the operating efficiency of the new system by simulation. The new suggested system shows about $39.25\%$ improvement in throughput and 3.75 times reduction of manpower compared to the current system.

• 한국대기환경학회지
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• 제9권4호
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• pp.329-339
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• 1993

Due to the global-convection currents, transboundary transport of air pollutants is widely observed in many regions of the world. This study was carried out to investigate the pattern of long-range transport of air pollutants in North East Asia, especially the impact of air pollutants originated in China and Japan on the air quality in Korea. From the meteorological data at the 850 mb surface from May 1986 through April 1987 at 54 obsevation stations in the North East Asia region, the backward and forward trajectories were calculated using interpolation method. And the contributions of pollution sources in neighbor countries to the air quality in Korea were analyzed. It was concluded that air pollution in China had a great influence on the air quality in Korea throughout the year : it could be transported to Korea just within 2 or 3 days most of the time. The trajectory analysis showed that pollution sources in Beijing. Liaoning Province, and Shandong Province, the most heavily industrialized areas in China., were the most influential for the air quality in Korea except for summer season. Durnig summer season, the air pollution in Shanhai and Japan could have moer influence on Korea. Such transboundary transport of air pollutants necessitate international cowork and cooperation in the region of North East Asia.