• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.485-497
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• 1998

To estimate the availability of the MCE for KOMPSAT I, mathematical models of H/W and S/W availability, the availability estimating methods for parallel and redundant system were presented. Furthermore, to improve and estimate the MCE system availability, we analyzed the computational procedure of redundant methods, and we also included effective switch choosing methods in this paper. The analytical results of the MCE system availability were estimated as follows: - 0.995216 not considering system redundancy, - 0.9955165 considering system redundancy, and -0.9963991 for the time of system real time operation.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.266-269
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• 2004

A satellite ground control system (SGCS) which monitors and controls a geostationary satellite 24 hours a day has to achieve the system architecture assuring high-level availability and redundancy scheme. The SGCS for Communication, Ocean, and Meteorological Satellite (COMS) is currently being developed in Korea, which will be implemented to satisfy high availability (HA), expansibility, and compatibility in design. In order to implement the system architecture to meet these characteristics, the SGCS for COMS introduces the concept of the real-time distributed system structure based on redundancy scheme for high availability, data replication and sharing, and CORBA middleware.

• The Korean Journal of Air & Space Law and Policy
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• v.14
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• pp.331-379
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• 2001

The purpose of this study is provide better suggestions to utilize the small aircraft by examining current situations of those airports. Then, the results of this study should help explain about the Availability of the airports for small aircraft in view of airplane exhibition, air-sports activity fields for aviation sports population, aviation theme park, and aviation-related education facility. This study examines current situations of the small airports for small aircraft which have been limited in their utility and compares the airports at the same level abroad. By examining these airports, this paper can make suggestions for the Availability of the small airports. Significance of the study lies in providing businessmen planning to invest the small airports and owners of airports with profitable consequences. At the macro level, it is expected to have a more effective development of land and an increase of aviation market value.

• Journal of The Korean Digital Architecture Interior Association
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• v.9 no.2
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• pp.5-16
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• 2009

The importance of playground, which is a central place in the outdoor space scheme for apartment and in children's outdoor activity, is increasing. The stature and availability in playground may be varied according to connection between playground and outdoor space and to characteristics of outdoor space. The purpose of this study is to arrange basic data in guidelines of a planning for supporting children's development and for activating its use in the apartment housing. This study conducted the field survey and questionnaire research after selecting 4-case apartment complexes based on the relevant preceding research. The survey results are as follows. Children were recognizing and preferring the playground as the central space in outdoor play activity. Mothers were preferring outdoor space adjacent to playground. There were the most responses with saying that a mother takes to play with a child. Children responded that the use of playground and the rides are the outdoor activity that they do the most. And, it was surveyed that there is difference in dweller's using playground by apartment complex according to characteristics of a planning for outdoor space. Given being connected with square with segregation of pedestrian and vehicle and with the resting space, the availability in playground was the highest. The availability in playground, which has high connection with diversely outdoor space elements while having good accessibility to the apartment building, was surveyed to be high. Playground had high preference in case of being connected with waterfront and resting space, rather than green zone. Diverse environmental artifacts and decorative fence may become a visually stimulus source that can activate the use of playground.

• Bulletin of the Korean Space Science Society
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• 2006.04a
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• pp.89-89
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• 2006

• Korean Journal of Optics and Photonics
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• v.33 no.3
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• pp.113-121
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• 2022

We analyze the link availability of satellite-to-ground free-space optical (FSO) communication systems in South Korea. Using ten-year meteorological data for five major cities (Seoul, Busan, Daegu, Daejeon, and Gwangju), we theoretically predict the link availability from the power losses induced by absorption, scattering, aerosols, and scintillation in the atmospheric channel. For accurate but conservative estimation of the link availability determined by cloud cover, we propose a loss model based on the maximum value of cloud droplet concentration. The results show that the link availability ranges from 45% to 70% when a single ground station is placed in a major city in South Korea and a 20-dB link budget is allocated for atmospheric loss. However, the availabilities improve to 90% and 97% when 3- and 5-site diversities are employed, respectively.

• KIEAE Journal
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• v.9 no.3
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• pp.21-27
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• 2009

The goal of this paper is to determine the suitability evaluation indices of a riverside reservoir space planning by classifying major indicators and calculating AHP(Analytical Hierarchy Process) based weights of them. The major indicators were set up based on literature review and questionnaire survey to experts. Four indicator categories were developed: location, environment, resource availability and economical efficiency. And they were divided into 12 sub-categories for calculating AHP-based weights. First, as for the major indicator categories, the calculation shows that the weighted index of environment is the most important at 0.458, followed by location at 0.128, economical efficiency at 0.170 and resource availability at 0.154. This suggests that environment is getting more public attention and the reservoir is regarded as a facility that is connected to a river. Those weight values were considered in calculating final weights for each of 12 sub-categories. Among them water quality and ecological environment take top ranks at 0.190 and 0.186, respectively. The lower ranks include access 0.112, resource availability of site 0.082, tourism resource 0.078, users 0.076, available land 0.052, area of site 0.031, shape of site and deterioration level 0.030 and percentage of private land 0.030 - which represents general considerations in other space planning. The difference of the top rank (water quality, 0.190) and the last one (percentage of private land, 0.027) is 0.163. The above result shows that users regard environmental aspect and resource availability more important than easiness of construction.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.489-498
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• 2003

Recently to introduce new services of ultra-high speed wireless access and systems beyond the 3rd generation mobile communication, 5 GHz band has been highly interested. As a way of getting the required frequency, it is considered that microwave relay bands below 6 GHz, which shows a slow decrease in demand and less cost-effectiveness, should be moved to other bands above 6 GHz. In this paper, as a tool for analyzing microwave link design and its service quality, the outage prediction based upon Vigants & Barnett＇s model is reviewed. To show outage and availability calculation, simulations are performed for the operating 4 GHz radio sites, and some results and features regarding frequency movement to 6.7 as well as 8 GHz are also discussed in terms of diversity techniques, bit error rate, and availability As the results, it is confirmed that only the diversity techniques of space or space and frequency can satisfy the annual objective of availability irrespective of frequency movement.

• Korean Journal of Optics and Photonics
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• v.29 no.2
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• pp.77-84
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• 2018

We analyze the link availability of terrestrial free-space optical (FSO) communication systems in Korea. For this purpose, we utilize several theoretical models to calculate the power losses induced by absorption and scattering in the atmospheric channel, using five-year meteorological data for three major cities in Korea (Seoul, Busan, and Daejeon). Also, we estimate the power variations at the receiver caused by scintillation in the data. Those power losses and variations are used to estimate the availability of FSO links in the three cities. The results show that link availability is estimated to be over 95% in Daejeon for a 3.5-km FSO link, when the transmitter power and receiver diameter are greater than 10 dBm and 7 cm respectively. Slightly worse link availabilities are obtained for Busan and Seoul.

• Journal of Broadcast Engineering
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• v.27 no.7
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• pp.999-1010
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• 2022

The increase in vehicle purchases worldwide is having a very significant impact on the availability of parking spaces. In particular, since it is difficult to secure a parking space in an urban area, it may be of great help to the driver to check vehicle parking information in advance. However, the current parking lot information is still operated semi-manually, such as notifications. Therefore, in this study, we propose a system for detecting a parking space using a relatively simple image processing method based on an image taken from the sky and evaluate its performance. The proposed method first converts the captured RGB image into a black-and-white binary image. This is to simplify the calculation for detection using discrete information. Next, a morphological operation is applied to increase the clarity of the binary image, and a template mask in the form of a bounding box indicating a parking space is applied to check the parking state. Twelve image samples and 2181 total of test, were used for the experiment, and a threshold of 40% was used to detect each parking space. The experimental results showed that information on the availability of parking spaces for parking users was provided with an accuracy of 95%. Although the number of experimental images is somewhat insufficient to address the generality of accuracy, it is possible to confirm the possibility of parking space detection with a simple image processing method.