• Journal of Environmental Science International
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• v.9 no.4
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• pp.303-309
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• 2000

The relationship between air temperature and sea surface temperature and studied using the daily air temperature and sea surface temperature data for 25 years (1970~1994) at 9 coastal stations in Korea. Seasonal variations of air temperature have larger amplitudes than those of sea surface temperature. The seasonal variations of air temperature leads those of sea surface temperature by 2 to 3 weeks. The anomalies of sea surface temperature and air temperature with time scales more than 1 month are more ghighly correlated than those of short term, with time scales less than 1 month. Accumulated monthly anomalies of sea surface temperature and air temperature for 6 months shwoed higher correlation than the anomailes of each month. The magnitudes of sea surface temperature and air temperature anomalies are related with the duration of anomalies. Their magnitudes are large when the durations of anomalies are long.

• Journal of the Korean Chemical Society
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• v.52 no.5
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• pp.588-592
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• 2008

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.509-515
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• 2001

In a square cavity, the flow phenomena in the surrounding of the bubble attached at the upper cooled solid wall were studied by using a thermo-sensitive liquid-crystal tracer and image processing techniques. This method offers the advantage of measuring the entire flow field in a selected plane within the fluid at a given instant of time in contrast to point by point method like T/C. Quantitative data of the temperature were obtained by applying a colour-image-processing to the. visualized image. As the growing of a bubble, In a bubble size appears the flow phenomena which the direction of flow is reversed in the entire temperature and flow field. The observed phenomena are described with regard to thermocapillary convection.

• Asia pacific journal of information systems
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• v.15 no.4
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• pp.89-107
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• 2005

As new information technology(IT) adoption continues to produce many investment opportunities, imperfectly informed IT managers keep trying to acquire credible external signals to update their knowledge on new technologies. Such learning processes usually help them to reach better IT adoption decisions. In some cases, however, the opposite of the goal is achieved. Most IT managers quickly converge to the same adoption decision independent of their private information. Interestingly, such information cascade is the outcome of each individual decision maker's rational choice. A technology acceptance model(TAM) is adopted that has been widely used to predict the end-user's acceptance of a new technology. A model with individual charact-eristics and information cascade variables is constructed to explain user's intention in adopting blogging. The model is empirically tested with surveyed data. The results show that individual characteristics and information cascades have significant impacts in the case of blogging.

• International Commerce and Information Review
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• v.1 no.2
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• pp.97-122
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• 1999

인터넷, PC통신 등과 같은 전자적인 수단에 의한 상거래가 활성화되면서 효율적인 물류업계의 대용전략이 요구되고 있다. 전자상거래하에서는 상류부문 예를 들어 상품의 주문 및 결제가 전자적으로 이루어지기 때문에 고객들은 물류서비스에서도 신속한 배송을 원하게 되었다. 또한 물류활동은 상거래 관련 당사자간의 수많은 정보가 유통되게 되기 때문에 물류부문도 이러한 정보의 흐름에 신속한 접속이 요구된다. 본 연구는 전자상거래하에서 물류의 효율적 관리를 위하여 사이버 물류시스템의 구축을 모색하는 방안을 제시하는 데 있다. 사이버 물류시스템이 구축되면 물류관련 당사자간을 인터넷을 통한 연계성이 확보됨으로써 정보의 원활한 흐름이 가능해지며 이로 인해 전체 물류시스템의 효율화가 증진될 것이며, 이로 인해 국내외 전자상거래의 활성화에 크게 기여할 것으로 예상된다.

• 한국해양학회지
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• v.22 no.4
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• pp.228-235
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• 1987

Based on the hydrographic data for 19 years (1968-1984) at 65 stations in the West Sea of Korea, we investigate the relationships between the sea surface temperature (SST) in winter and the bottom water temperature (BWT) in summer. The spatially-averaged anomalies of BBT are highly correlated with those of SST during the preceding winter. However, due to advection of heat by ocean currents, the spatial pattern of BWT anomaly in summer does not closely resemble that of SST anomaly in the preceding winter.

• Journal of environmental and Sanitary engineering
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• v.15 no.1
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• pp.88-94
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• 2000

The purpose of this study was to analyze and compare the contents of minerals and ionic components in domestic commercial natural mineral waters, and to investigate the relationship between water quality and characteristics of suspended and rocks there of its source. All mineral waters tested in this study met the korean mineral water quality guideline, although chemical components varied widely depending upon the geological characteristics and degree of urbanization of the source area or physical water treatment method. The water quality of commercial bottled water was different from that of source water, especially in cationic components, and showed a tendency to become worse with time elapsed. The water quality on the bottle was also different from the measured quality.

• Explosives and Blasting
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• v.20 no.3
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• pp.49-58
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• 2002

발파공법이 소개된 이후로 계속해서 많은 우수한 발파이론이 발표되어 왔다. 그러한 이론들의 저변에 있는 궁극적인 목표는 효율의 증가와 경제성이다. 이에 본 연구는 Air-Tubes 발파공법을 소개하고 터널에서 일반발파와 비교하여 그 발파효율을 검토해 보았다 연구의 배경이 되는 곳은 산청군 시천면 내대리와 하동관 묵계리를 연결하는 2차선 국도 터널 공사 현장이며 전체 총연장은 2Km이다. 진동측정방법은 하나의 발파진동을 4개의 측정기로 측정하여 데이터분석에 사용하였다. 일반발파와 Air-Tubes의 진동측정을 4개소에서 각각 6회씩 실시하여 총 24개씩의 진동측정 데이타를 얻었고 회귀분석을 실시하여 95% 신뢰도의 발파진동 추정식을 얻었다. 시험발파 및 진동측정에 이어 매 발파마다 광파측량을 실시하여 진행장을 구하였으며 사용한 장약량은 Air-Tubes 발파시 25% 정도 적게 사용하였고 발파진동이 23% 감소하였다. 발파당 굴진장 및 Smooth blasting 발파시의 벽면의 상태는 동일하고 파쇄석의 크기는 Air-Tubes 발파시 더 작게 나타난다.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.157-159
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• 2008

This paper describes modeling and analysis of magnetic inrush for a 765kV transformer using EMTP-RV. EMTP-RV generates the core flux and thus helps show the behavior of the core, i.e. hysteresis characteristics. The results of three kinds of the magnetic inrush such as initial inrush, sympathetic inrush, and recovery inrush are included. This modelling can help the design of a protection relay for a transformer.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.18-20
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• 2007

A coupling capacitor voltage transformer (CCVT) is used in an extra high voltage power system to obtain the standard low voltage signal for protection and measurement. To suppress the effects of ferro-resonance more effectively, a three winding CCVT is used. This paper proposes an algorithm for compensating the secondary voltage of the three winding CCVT. With the secondary voltage of the three winding CCVT, the secondary and tertiary currents are obtained; the primary winding current is obtained by considering non-linear characteristics of the core; the voltage across the capacitor and the inductor are calculated and then added to the measured voltage to compensate the secondary voltage. Test results indicate that the algorithm can reduce the errors of the three winding CCVT significantly.