• 대한교통학회지
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• 제26권5호
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• pp.41-49
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• 2008

세계화를 통해 글로벌 공급사슬은 더욱 복잡해지고, 고객들은 모든 물류서비스를 통합적으로 제공받을 수 있는 기업에 대한 의존도가 높아짐에 따라 고객들은 물류 기업에 대해서 가격뿐만 아니라 운영적인 측면에서 높은 효율성을 요구하고 있다. 이에 본 연구에서는 자료포락분석(Data Envelopment Analysis)을 중심으로 전세계 물류산업의 효율성의 추이와 비효율성에 영향을 미치는 요소들에 대한 연구를 진행하였다. 그 결과를 요약하면, 5개년간 세계의 물류산업의 효율성은 높아지는 추세를 보이고 있었으며, 비효율성은 규모에 의한 비효율성보다는 순수기술효율성에 의해 나타난 비효율성에 의해서 나타나고 있었다. 비효율성에 영향을 미치는 외부적인 요소를 살펴보면, 우선 세계화는 비효율성에 영향을 주고 있다. 세계화의 요소 중에서는 경제적인 요소보다는 전반적인 세계화 정도가 더 영향을 미쳤으며, 인프라와 관련되어서는 인력, 금융적 지원, 기반 등 소프트웨어적 측면의 영향력이 더 유의했으며 법제도적인 측면에서는 집행의 투명성, 법제도의 효과가 유의하게 영향을 미치는 것을 밝혀냈다.

• 한국태양에너지학회 논문집
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• 제32권3호
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• pp.68-76
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• 2012

Since the solar energy resource is the main input for sizing any solar energy utilization system, it is essential to utilize the solar radiation data as an application and development of solar energy system increase. It will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at 16 different locations in Korea and for the more detailed analysis, images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. From the results, the measured data has been collected at 16 different stations and estimated using satellite at 44 different stations over the Korean peninsula from 1982 to 2010. The Result of analysis shows that the annual-average daily global radiation on the horizontal surface is 3.66 $kWh/m^2/day$ and estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.2 to +3.7 % from the measured values.

• 한국산학기술학회논문지
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• 제21권1호
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• pp.14-19
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• 2020

본 논문은 차등 위성항법 보정 시스템을 이용한 측위 오차 보정을 통해 소형 드론의 위치를 정밀하게 계측할 수 있는 시스템 구현에 대해 서술하고 있다. 본 시스템은 고정된 위치에 자리하는 기준국과 실시간으로 움직이는 이동국(드론)으로 이루어져 있다. 자체 기준국 위치 정보와 국가에서 제공하는 관측 정보를 함께 후처리하여 기준국의 정밀 좌표를 획득하는 과정에 대해 서술하고, 이동국을 정밀 추적하기 위한 차등 위성 항법 시스템의 하드웨어 및 소프트웨어 구성에 대해 설명한다. 기준국 및 이동국 구현에 있어 저가의 경량 위성 항법 수신기 및 오픈소스 소프트웨어 코드와 라이브러리를 활용하여 범용성과 경제성을 극대화 하였으며, 오차 보정 정보 송수신에는 비 면허 주파수 대역 무선통신인 지그비(Zigbee)를 사용하였다. 본 시스템을 이용하여 소형 드론 위치 추적 시험 결과, 평균 측위 오차가 0.8m 및 최대 측위 오차가 1.2m로, 단일 위성 항법 수신기를 사용했을 경우 대비 오차가 86% 개선됨을 확인할 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.76-82
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• 1998

Increase of greenhouse gas due to $CO_2$ and CH$_4$ gases would cause the global warming in the atmosphere. According to the global circulation model, it is pointed out in the Okhotsk Sea that the large increase of atmospheric temperature might be occurredin this region by global warming due to the doubling of greenhouse effectgases. Therefore, it is very important to monitor the sea ice extents in the Okhotsk Sea. To improve the sea ice extents and concentration with more highly accuracy, the field experiments have begun to comparewith Airborne Microwave Radiometer (AMR) and video images installed on the aircraft (Beach-200). The sea ice concentration is generally proportional to the brightness temperature and accurate retrieval of sea ice concentration from the brightness temperature is important because of the sensitivity of multi-channel data with the amount of open water in the sea ice pack. During the field experiments of airborned AMR the multi-frequency data suggest that the sea ice concentration is slightly dependending on the sea ice types since the brightness temperature is different between the thin and small piece of sea ice floes, and a large ice flow with different surface signatures. On the basis of classification of two sea ice types, it is cleary distinguished between the thin ice and the large ice floe in the scatter plot of 36.5 and 89.0GHz, but it does not become to make clear of the scatter plot of 18.7 and 36.5GHz Two algorithms that have been used for deriving sea ice concentrations from airbomed multi-channel data are compared. One is the NASA Team Algorithm and the other is the Bootstrap Algorithm. Intrercomparison on both algorithms with the airborned data and sea ice concentration derived from video images bas shown that the Bootstrap Algorithm is more consistent with the binary maps of video images.

• 한국컴퓨터정보학회논문지
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• 제26권12호
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• pp.323-330
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• 2021

본 논문에서는 독서에 대한 학생들의 태도와 성향이 코딩교육에 어떤 영향을 미치는지 파악하기 위한 연구를 진행하였다. 관련 데이터를 3가지 영역(독서, 코딩, 여가)으로 나누어 수집하고 분석하였다. 독서 영역에서는 선호도서, 선호 독서 방법 데이터 등을 수집하였고 코딩영역에서는 선행학습여부, 주요 컴퓨터 활용 작업, 코딩 학습에 주당 사용한 시간 등을 수집하였고, 여가 영역에서는 여가 활동과 주당 소비 시간을 수집하였다. 코딩교육에 어려움을 느끼는 비전공 학생들의 문제점을 확인하기 위해 선호 독서 방법을 기준으로 데이터를 분류 및 분석하였다. 발췌독하는 학생 그룹이 코딩교육에서 가장 좋은 성취도(평균60.1)를 나타내었고, 다독하는 학생 그룹이 가장 낮은 성취도(평균48.4)를 나타내었다. 다독하는 학생 그룹은 타 독서 방법을 선호하는 학생 그룹에 비해 코딩 학습에 더 많은 시간을 사용하였지만 가장 낮은 성취를 나타내고 있음을 확인할 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.388-391
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• 2005

The characteristics of the total ozone variations measured by the ground-based Brewer Ozone Spectrophotometer and the Total Ozone Mapping Spectrometer (TOMS) over Pohang are statistically examined from January 1994 to December 2004. First of all, in the correlation analysis of the total ozone measured from the Brewer Ozone Spectrophotometer and the TOMS, the correlation coefficient was 0.88 and the used data were 2190. The annual mean value of the total ozone is 311 DU with the standard deviation of 13 DU. The maximum and the minimum value were found in March (343 DU) and in September (282 DU), respectively. It was also revealed that the longest seasonal variation is in Spring (341 DU) and the smallest is in Autumn (283 DU). The time series data of the total ozone indicates that the annual variation is significant and the variations for three months and six months are relatively weak. Finally, the annual mean total ozones in Pohang (Brewer), Seoul (Brewer) and Busan (TOMS) are 312 DU, 324 DU and 304 DU, respectively.

• 대기
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• 제21권4호
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• pp.439-446
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• 2011

NCEP reanalysis data were analyzed in order to provide distribution of global wind resource and wind speed in the surface layer for the years 2000-2009. Wind speed at 10 m above ground level (AGL) was converted to wind speed at 80 m above the ground level using the power law. The global average 80 m wind speed shows a maximum value of $13ms^{-1}$ at the storm track region. High wind speed over the land exists in Tibet, Mongolia, Central North America, South Africa, Australia, and Argentina. Wind speed over the ocean increased with a large value in the South China Sea, Southeast Asia, East Sea of the Korea. Sea surface wind in Western Europe and Scandinavia are suitable for wind farm with a value of $7-8ms^{-1}$. Areas with great potential for wind farm are also found in Eastern and Western coastal region of North America. Sea surface wind in Southern Hemisphere shows larger values in the high latitude of South America, South Africa and Australia. The distribution of low-resolution reanalysis data represents general potential areas for wind power and can be used to provide information for high-resolution wind resource mapping.

• 대기
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• 제17권1호
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• pp.1-15
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• 2007

A constraint based on climatology is introduced to the cost function of the three-dimensional variational assimilation (3dVar) to correct the error of the zonal mean wind structure in the global data assimilation system at Korea Meteorological Administration (KMA). The revised cost function compels the analysis fit to the chosen climatology while keeping the balance between the variables in the course of analysis. The constraint varies selectively with the vertical level and the horizontal scale of the motion. The zonally averaged wind field from European Centre for Medium-Range Weather Forecasts Re-Analysis 40 (ERA-40) is used as a climatology field in the constraint. The constraint controls only the zonally averaged stratospheric long waves with total wave number less than 20 to fix the error of the large scale wind field in the stratosphere. The constrained 3dVar successfully suppresses the erroneous westerly in the stratospheric analysis promptly, and has been applied on the operational global 3dVar system at KMA.

• The Journal of Asian Finance, Economics and Business
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• 제3권4호
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• pp.43-56
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• 2016

The research aims to help merchant acquiring institutions gain a better insight on what merchant establishments in the Singapore market perceive of the costs they incur due to credit card acceptance. The research attempts to study the Singapore market and establish if increased credit card usage does increase costs for the merchant establishments that accept credit cards, this will help to acquire institutions in Singapore have a better understanding of merchant perceptions and what drives or deters credit card acceptance in the Singapore market. The survey was based on an interview of merchant establishments and the views of the merchants and was not based on their financial data. As a first step, the variables used in the survey were tested for interdependence using Chi-square tests; subsequently data reduction using factor analysis was performed and finally linear regression to establish a relation between dependent and independent variables. Merchant establishment believe accepting credit cards and increasing volume is costlier compared to another form of payment, but have mixed awareness about interchange fee. It also indicated that interchange fee and cardholder benefits are independent of the merchant establishments. The study only broadly attempts to gauge merchants view if increased credit card usage has increased costs for them.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.162-165
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• 2004

The authors' previous study found an interannual covariability between actual evapotranspiration (ET) and the Normalized Difference Vegetation Index (NDVI) over northern Asia. This result suggested that vegetation controls interannual variation in ET. In this prior study, NDVI data from the Pathfinder AVHRR Land (PAL) dataset were analyzed. However, studies of NDVI interannual change are subject to uncertainty, because NDVI data often contain errors associated with sensor- and atmosphere-related effects. This study is aimed toward reducing this uncertainty by employing NDVI dataset, from the Global Inventory Monitoring and Modeling Studies (GIMMS) group, in addition to PAL. The analysis was carried out for the northern Asia region from 1982 to 2000. 19-year interannual change in PAL-NDVI and GIMMS-NDVI were both compared with interannual change in model-assimilated ET. Although the correlation coefficient between GIMMS-NDVI and ET is slightly less than for PAL-NDVI and ET, for both NDVI datasets the annual maximum correlation with ET occurs in June, which is near the central period of the growing season. A significant positive correlation between GIMMS-NDVI and ET was observed over most of the vegetated land area in June as well as PAL-NDVI and ET. These results reinforce the authors' prior research that indicates the control of interannual change in ET is dominated by interannual change in vegetation activity.