• Journal of the Institute of Electronics Engineers of Korea TC
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• 제44권6호
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• pp.31-39
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• 2007

In this paper, a system for real-time or periodic measurement and analysis of RF parameters such as forward transmit power and pilot power in CDMA base station systems is proposed. Such RF characteristic parameter measurement can be prevented from system fault and used to achieve optimal service quality and maximum investment return through cell coverage expansion, subscriber capacity increase and so on. For forward power measurement, the local oscillator frequency for the detector is varied so that the transmit power for all channels can be measured. The channel power measurement can be used to analyze the variation in transmit power for changes in voice traffic. By comparing to forward $E_c/I_o$, the pilot channel power can be deducted, which can be used to determine uy degradation in transmit section modules such as the high dover amplifier. Since an accurate analysis of carefully measured data using the CDMA level detector must be made, the system is designed so that measurement errors due to changes in crest factor with modulation method can be overcome.

• The Bulletin of The Korean Astronomical Society
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• 제37권2호
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• pp.211.2-211.2
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• 2012

천리안위성은 통신, 해양, 기상 임무를 띤 우리나라 최초의 정지궤도복합위성으로 지난 2010년 6월 27일 성공적으로 발사된 후 동경 128.2도, 적도 상공 약 35,800 km 고도의 정지궤도에 안착되었다. 이 후 약 6개월 여의 궤도상시험 기간과 2개월의 안정화 기간을 거쳐 2011년 4월 1일, 기상청은 위성자료 서비스를 위한 정규운영을 시작하였다. 천리안위성의 기상탑재체인 기상영상기는 다중채널 복사계로 한반도 주변뿐만 아니라 전 지구적 기후 변화 및 대기 운동 그리고 급변하는 기상상황을 감시하기 위해 실시간 관측과 전송 시스템을 갖추고 있다. 이 기상영상기를 운용하는 기상청 국가기상위성센터 지상국에서는 자료수신 및 영상전처리시스템을 갖추고 수신된 위성신호로부터 영상 분리 후 복사보정 및 기하보정을 수행하며, 위성자료배포시스템을 통해 일정 시간 간격 내에 사용자들에게 처리 자료를 배포하고 있다. 영상 복사보정은 기상영상기 내의 각 채널별 디텍터가 감지한 지구복사휘도의 전기적 신호를 지상에서 복사휘도와 휘도온도 값으로 변환하는 작업이다. 절대검정체로서 흑체와 우주보기 값을 이용하는 적외채널과 달리, 가시채널 디텍터는 절대검정체가 탑재되어있지 않기 때문에 우주보기 값 외에 대리검정 방법을 이용한다. 이러한 가시채널 노화도 분석에 달 관측을 통한 비교 분석이 한 방법으로 제시되고 있다. 천리안위성 기상영상기의 정규운영 1년간의 가시채널 디텍터의 노화도는 6 % 이내로 측정되었고, 이는 일반적인 정지궤도위성 센서의 노화도인 6 % 내외 값 변화량에 견주어 잘 운용되고 있음을 시사한다. 본 논문에는 천리안위성 기상영상자료의 품질 및 매개변수의 변화 경향도 함께 제시하였으며, 달을 이용한 기상영상기 노화 분석과 보정에 관한 내용을 싣고 있다.

• The Transactions of the Korean Institute of Power Electronics
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• 제13권4호
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• pp.278-286
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• 2008

This paper investigates the fault generation type and the cause of output interruptionsin bulky with $30^{\sim}500[KVA]$ double conversion UPS, and proposes the fault detection method to improve the reliability of power supply used in the critical load in industry. Identifies its existing way of detecting a quality of inverter output it to bypass when exceeds its expectation. Under a UPS managing system, when an inner (Power device, Controller, CPU) fault occurs it disrupts the power supply and these occurrences has been verified by the results of experiments and application results. To overcome these problems, the proposed method constructs independently a fault-detection, a bypass-control device and a triple power supply apart from the conventional UPS operation. Also the detection point is changed to the preceding of a circuit breaker, a reference of fault detection is modified to avoid any clash and the breaking equipment is attached to intercept a spread of accident. As a result of applications of these developed systems to 242 UPS which was installed purposefully to the communication power supply, the service errors has not occurred in the UPS for two years since 2006.

• Journal of the Korea Institute of Military Science and Technology
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• 제13권5호
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• pp.903-909
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• 2010

ADAS is the air defense control system performing air surveillance and identification of ROK and near air. This system is self-developed by Air Force, currently operated successfully as the alternative system of MCRC. ADAS processes converting and combining transferred the real time radar data detected by radars. additionally, it displays significant radar data as producing in tracks. Then, it uses the message queue for IPC(Inter Process Communication). the various tactical data processed in the server is ultimately send to the network management process through the message queue for transmitting to the weapon director console. the weapon director receives this transmitted tactical data through the console to execute air defense operations. However, there is a problem that data packet is delayed or lost since the weapon Director does not receive as the amount of tactical data from the server overflowed with air tracks and missions increased. This paper improved the algorism to display and transmit the various tactical data processed from ADAS server to numbers of the weapon director console in the real time without any delay or lost. Improved the algorism, established at exercise, the development server in the real operation network and the weapon director console, is proved by comparing the number of sending tactical data packets in the server and receiving packets in the weapon director.

• Journal of the Korea Society of Computer and Information
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• 제17권2호
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• pp.13-21
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• 2012

Mobile data caching is usually used as an effective way to improve the speed of local transaction processing and reduce server load. In mobile database environment, due to its characters - low bandwidth, excessive latency and intermittent network, caching is especially crucial. A lot of mobile data caching strategies have been proposed to handle these problems over the last few years. However, with smart phone widely application these approaches cannot support vast data requirements efficiently. In this paper, to make full use of cache data, lower wireless transmission quantity and raise transaction success rate, we design a new mobile data caching synchronization strategy based on in-demand and replacement priority. We experimentally verify that our techniques significantly reduce quantity of wireless transmission and improve transaction success rate, especially when mobile client request a large amount of data.

• Journal of the Korean Society of Food Culture
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• 제37권5호
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• pp.429-437
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• 2022

This study evaluated the quality of school milk programs and analyzed the relative importance of school milk program selection attributes using conjoint analysis. The survey was conducted on students from middle and high schools in metropolitan cities that provide school milk programs. Responses were received from 414 students and the data was subjected to frequency analysis, t-test, and conjoint analysis using the SPSS Statistics Package. While evaluating white milk in the school milk program, middle school students rated 'packaging condition' (4.23) the highest, high school students rated 'nutrition' (4.64) the highest, and their evaluation of all the quality attributes was significantly different from that of middle school students (p<0.001). Overall satisfaction scores too, showed a significant difference between high school (4.46) and middle school students (4.01) (p<0.001). Processed milk & dairy products had the highest satisfaction score in the attribute of 'serving time' (4.57). The relative importance of the choice attributes of the school milk program was in the order of 'number per item' (62.260%), 'temperature' (25.708%), and 'serving method' (12.032%) for all students. The school milk program most preferred by all students and middle school students was to provide milk at a refrigerated temperature, select white milk three times a week, processed milk, fermented milk, and cheese twice a week, and provide it at the desired time.

• The Transactions of the Korea Information Processing Society
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• 제4권1호
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• pp.215-223
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• 1997

The advantages of service in satellite links are representatively a long distance and large capacity transfer and simultaneous communication. And terrestrial links are of high speed and high quality data transfer Therefore a combined form of characteristics of satellite and terrestrial links is desirable to furnish a good quality service to subscribers. And in satellite links an analysis method and a simulation method of file transfer are conducted to evaluate the efficiency of file transfer. The parameters are used the message length and transmission time, and the number of chain record and transmission time. From the results of evaluation, in satellite links, it is found that when the message length is shorter than 512 bytes, the file transmission time becomes extremely long and when the message length is set at 1024 bytes, the file transmission time abruptly increase from 2048 bytes. Also it is confirmed that when the number of chain record is under 15, the file transmission time becomes extremely long and if the number increase up to 90,the time becomes gradually short and over 90,it becomes constant.Therefore,from the result of file transmission in th case of utilizing satelite links,it is confirmed that the optimum message length in the minmum transmission time is present closely at 1024 bytes.Also it is confirmed that when the satelite transmission sped becoms smaller from 24kbps to2400bps,the optimum message length also becomes smaller from 640 bytes to 256bytes.

• Journal of Broadcast Engineering
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• 제9권4호
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• pp.411-423
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• 2004

In Korea, Eureka-147 DAB (Digital Audio Broadcasting) temporarily decided as the standard system for digital audio broadcasting was evolved into DMB (Digital Multimedia Broadcasting) to complement the technical vulnerability in mobile reception of terrestrial DTV. According to introducing video service in T-DMB (Terrestrial DMB), 'Terrestrial DMB Experimental Broadcasting for Video Service', a national project of the MIC (Ministry of Information and Communication), was done for verifying the possibility of video service via T-DMB. The main objective of the project is computing the effective field strength and coverage for making a plan to build T-DMB broadcasting network and developing transmitting and receiving equipment. In case of digital broadcasting, it is absolutely essential to measure BER (Bit Error Rate) and electric field strength in order to evaluate coverage and quality of received signal. In this paper, we implement an integrated mobile measurement system for T-DMB. For this purpose, we propose efficient data structure and algorithm for BER measurement. By adding GPS (Global Positioning System) and electric field strength measurement parts into BER measurement part, we complete the integrated mobile measurement system, and then verify it by experiments and field tests. The developed system was used in a national project, 'Terrestrial DMB Experimental Broadcasting for Video Service' and measurement results will be used as fundamental data for building T-DMB broadcasting network.

• KIPS Transactions on Computer and Communication Systems
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• 제11권11호
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• pp.381-394
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• 2022

Recently, due to the personalization and customization of data, Internet-based services have increased requirements for real-time processing, such as real-time AI inference and data analysis, which must be handled immediately according to the user's situation or requirement. Real-time tasks have a set deadline from the start of each task to the return of the results, and the guarantee of the deadline is directly linked to the quality of the services. However, traditional container systems are limited in operating real-time tasks because they do not provide the ability to allocate and manage deadlines for tasks executed in containers. In addition, tasks such as AI inference and data analysis basically utilize graphical processing units (GPU), which typically have performance impacts on each other because performance isolation is not provided between containers. And the resource usage of the node alone cannot determine the deadline guarantee rate of each container or whether to deploy a new real-time container. In this paper, we propose a monitoring technique for tracking and managing the execution status of deadlines and real-time GPU tasks in containers to support real-time processing of GPU tasks running on containers, and a node list management technique for container placement on appropriate nodes to ensure deadlines. Furthermore, we demonstrate from experiments that the proposed technique has a very small impact on the system.

• Journal of the Korean Society for information Management
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• 제39권4호
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• pp.191-213
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• 2022

With a view to providing a high-quality policy information service beyond the existing national task service of the national policy information portal (POINT) of the National Library of Korea Sejong, it would be necessary to effectively provide the policy data needed for the implementation of the new national tasks. Accordingly, in this study, an attempt has been made to find a way to connect and develop the BRM-based national tasks and the policy information contents. Towards this end, first, the types of national tasks and the contents of each field and area of the government function's classification system were analyzed, with a focus placed on the 120 national tasks of the new administration. Furthermore, by comparing and analyzing the national tasks of the previous administration and the current information, the contents ought to be reflected for the development of contents related to the national tasks identified. Second, the method for linking and collecting the policy information was sought based on the analysis of the current status of policy information and the national information portal. As a result of the study, first, examining the 1st stage BRM of the national tasks, it turned out that there were 21 tasks for social welfare, 14 for unification and diplomacy, 17 for small and medium-sized businesses in industry and trade, 12 for general public administration, 8 for the economy, taxation and finance, 6 for culture, sports and tourism, science and technology, and education each, 5 for communication, public order and safety each, 4 for health, transportation and logistics, and environment each, 3 for agriculture and forestry, 2 for national defense and regional development each, and 1 for maritime and fisheries each, among others. As for the new administration, it is apparent that science technology and IT are important, and hence, it is necessary to consider such when developing the information services for the core national tasks. Second, to link the database with external organizations, it would be necessary to form a linked operation council, link and collect the information on the national tasks, and link and provide the national task-related information for the POINTs.