• Journal of Astronomy and Space Sciences
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• 제36권3호
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• pp.169-180
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• 2019

In this study, a batch least square estimator that utilizes optical observation data is developed and utilized to determine geostationary orbits (GEO). Through numerical simulations, the effects of error sources, such as clock errors, measurement noise, and the a priori state error, are analyzed. The actual optical tracking data of a GEO satellite, the Communication, Ocean and Meteorological Satellite (COMS), provided by the optical wide-field patrol network (OWL-Net) is used with the developed batch filter for orbit determination. The accuracy of the determined orbit is evaluated by comparison with two-line elements (TLE) and confirmed as proper for the continuous monitoring of GEO objects. Also, the measurement residuals are converged to several arcseconds, corresponding to the OWL-Net performance. Based on these analyses, it is verified that the independent operation of electro-optic space surveillance systems is possible, and the ephemerides of space objects can be obtained.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.203-206
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• 2009

기상 데이터는 측정 장소의 산재로 인하여 매우 성긴 형태의 값으로 수집된다. 따라서 특정 건물이나 지하철 등 제한된 도시 공간에서 정밀한 기상 정보를 수집하는 것은 별도의 측정 장비를 설치해야 하는 비용 문제를 야기한다. 이 논문에서는 최근 관심을 끌고 있는 센스 네트워크 기술을 활용하여 휴대폰을 센서로 기상 지도 생성 및 서비스 응용 기법에 대하여 고찰한다.

• 한국실내디자인학회논문집
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• 제19권2호
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• pp.15-23
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• 2010

First appeared in the 1970s, the underground shopping mall has been spreading across the country, and there reportedly exist 77 malls in the 2010. After over 30 decades operation, many underground shopping malls are now under the planning phase for renovation in many cities. This study considers the renovation issue of the underground shopping mall in the perspective of spatial re-configuration. A case is taken from Kangnam TerminalUnderground Shopping Mall in Seoul for detailed observation and suggestion. The monotonous and confusingspatial layout of the existing mall is investigated by observation methods. Based on the observation, a modifiedplan is suggested and evaluated by means of computer simulation program, Depth Map. The program mainly deals with visual network analysis in order to quantify the optical exposure in a given space. It is argued in this paper that the enhanced visual connectedness could affect the pedestrian performance positively in the shopping mall, and this leads to an easy and quick access to each shops in users' stand point. It is thought that this configurational solution for the remodelling of a specific case would be an effective reference for other malls in the country which are facing the similar problems.

• 한국항공운항학회지
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• 제23권1호
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• pp.85-95
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• 2015

A responsibility of superior management in an airline has become enormous due to rapid increase of airline's organization and its network. Even though a leadership of superior management is believed to be an important factor, it is almost impossible for management to be responsible for all the areas of an airline organization. This is why leadership should be go down to working level people. Self-leadership means that working level people possess leadership, delegated by their superior persons, and improve their work environment with the leadership as well as related right and responsibility. This paper has tried to find out the components of self-leadership perceived by foreign cabin crews and analyzed the impact of self leadership into airline's organizational effectiveness. Based on empirical research results, this paper would suggest administrative and operational implications of managing foreign cabin crews in K-airline. It was found out foreign cabin crews perceive that self reward and self evaluation have a positive impact on self observation factor. The self observation factor has a significant effect on self goal. The self goal is analyzed as a major factor which results in organizational effectiveness.

• 천문학회보
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• 제41권2호
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• pp.36.2-36.2
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• 2016

In mm-VLBI, the quality of observation data is largely affected by atmospheric effect. The most challenging matter is that the phase of correlator output fluctuates rapidly resulting from a variation of atmospheric propagation delay. Consequently, it is demanding to achieve high Signal-to-Noise ratio by integrating data in time domain before calibrating atmospheric delay. However, Korean VLBI Network (KVN) has a unique system to make a 4-frequency (22/43/86/129 GHz) simultaneous observation in mm-wavelength and Frequency Phase Transfer (FPT) calibration technique has effectively removed atmospheric delay in the simultaneous multi-frequency observation of the KVN. For astrometric and astrophysical studies, we evaluated the FPT performance of KVN in various observing conditions. Using the total 38 bright AGNs, we have compared atmospheric conditions such as ground-based weather information, system temperature, atmospheric delay with the calibration results of FPT at 22/43/86/129 GHz during the five experiments in 2013, and quantified its performance in terms of coherence function and Allan variance. We present the analysis result of the relation between the FPT performance and observing conditions.

• 한국환경과학회지
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• 제26권9호
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• pp.1023-1029
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• 2017

We studied the distribution of air temperature using the high density urban climate observation network data of Daegu. The observation system was established in February 2013. We used a total of 38 air temperature observation points (23 thermometers and 18 AWSs). From the distribution of monthly averaged air temperatures, air temperatures at the center of Daegu were higher than in the suburbs. The daily minimum air temperature was more than or equal to $25^{\circ}C$ and the daily maximum air temperature was more than or equal to $35^{\circ}C$ at the elementary school near the center of Daegu. Also, we compared the time elements, which are characterized by the diurnal variation of surface air temperature. The warming and cooling rates in rural areas were faster than in urban areas. This is mainly due to the difference in surface heat capacity. These results indicate the influence of urbanization on the formation of the daily minimum temperature in Daegu.

• 천문학논총
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• 제20권1호
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• pp.125-134
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• 2005

In this paper, we propose a small-scale Gigabit VLBI observing system for the Korean VLBI Network (KVN) under construction. The system consists of high-speed sampler, IP-VLBI board, PC-VSI board, and software correlator. Radio signal received by receiver is sampled by high-speed sample. at 1 Gsps (Gigabit sample per second) rate with 2 bits quantization. The digitized signal is recorded in PC and the software correlator does the cross correlation. IP-VLBI board will be used for the geodesy VLBI observation, while PC-VSI board is for the astronomical VLBI observation. The PC-VSI board adopts the VSI-H (VLBI Standard Interface Hardware). The proposed system is based on commercial PCs and therefore can be built inexpensively.

• 천문학논총
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• 제19권1호
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• pp.101-107
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• 2004

This paper describes the digital back-end system for getting the data to analyze the user observation mode by digitalize the analog data after receiving the space radio using the radio telescope, The received analog data will be digitalized by high-speed sampler with 1 Gsps for 4 channel frequency band of millimeter wave, and the digital data will be transported through the fiber-optic digital transmission system and WDM(wavelength division multiplex) to observation building, The wideband digital FIR(Finite Impulse Response) filters analyze the data for user observation mode to record the data in high-speed recorder with 1 Gbps. In this paper, we introduce the overall system configuration and features combined by various information and communication technology in radio astronomy briefly, which will be adopted by KVN(Korean VLBI Network).

• 한국환경과학회지
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• 제26권12호
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• pp.1399-1405
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• 2017

We compared the spatial distribution of several heat stress indices (the Wet-Bulb Globe Temperature(WBGT) index, Environmental Stress Index (ESI), and Modified Discomfort Index(MDI)) for the heat wave of June 6~August 26, 2016, in Daegu. We calculated the heat stress indices using data from the high density urban climate observation network in Daegu. The observation system was established in February. 2013. We used data from a total of 38 air temperature observation points (23 thermometers and 18 automatic weather stations). The values of the heat stress indices indicated that the danger level was very high from 0900-2000h in downtown Daegu. The daily maximum value of the WBGT was greater than or equal to $35^{\circ}C$. The differences in the heat stress indices from downtown and rural areas were higher in the daytime than at nighttime. The maximum difference was about 4 before and after 1400h, and the time variations of the heat stress indices corresponded well. Thus, we were able to confirm that the ESI and MDI can be substituted with the WBGT index.

• 천문학회보
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• 제36권2호
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• pp.90.2-90.2
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• 2011

At Kyoto University, a continuous solar full-disk observation in CaII K line had been done during 44 years of 1926 - 1969. The observation was done with a Askania spectroheliograph on daily base. The images were taken on photographic plates. We started a project to archive these image data into a digital database which will be open to the public for scientific researches. One of the scientific usage of the database is to study the long term variation of the solar chromospheres. Since the area of CaII K plage area is a measure of solar chromospheric heating, we can do comparative study of the sunspot cycle and the chromospheric heating cycle of the sun. Another interesting field of scientific utilization of the database is the long term variation of the heating of terrestrial upper atmosphere. As was shown by Yokoyama, Masuda and Sato (2005), the area of the CaII K plage is a good proxy measure of solar EUV irradiation onto the upper atmosphere of the earth. Thus the completion of our database will serve to supply a basic and long-span data for upper atmospheric heating issues by the cooperative study with the Inter-university Upper atmosphere Global Observation NETwork (IUGONET) developed in Japan.