• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.267-276
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• 2007

In OSPF, the larger and more unstable the area, the greater the likelihood for performance problems associated with routing protocol recalculation. Generally, an area should have no more than 50 routers. Areas with unstable links should be smaller. Military tactical data network is used for military operations during war-time. It consists of wireless network for mobility of node. Thus, it has low-bandwidth and unstable property. In addition, it is expected that many kinds of router-failure, Link-failure and recovery at emergency period. However, Military tactical data network is designed with about one and half times the number of recommendation. This paper proves that the traffic is limited by the increase of re-calculation of area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1963-1970
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• 1999

Researches in draft recommendation H.263 have been made in ITU-T LBC group to broaden its range of useful application and to improve its compression performance. The form of added and revised draft text of H.263 is informally known as “H.263+”. In this paper, we analyzed the characteristics of H.263+ negotiable option modes for four image classes. Based on the analysis results, we proposed the adaptive selection scheme of H.263+ option modes by using a scene change detector for a mixed image class. In case of using the proposed scheme, we obtained the 1.6dB improvement in PSNR compared to the basic mode of H.263, and the 0.4~1.0 dB improvement in PSNR compared to the fixed usage scheme of H.263+ negotiable option modes. In respect to used bits per frame, fewer bits are produced than the basic mode H.263 and the foxed usage scheme of H.263+ option modes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.7
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• pp.550-559
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• 2017

In order to maintain communication while the vehicle is moving, satellite azimuth angle and elevation angle correction are needed in real time. The elevation angle correction affects the system G/T according to the variation of the external noise temperature flowing into the antenna. G/T is expressed as a ratio of power gain G to noise temperature T and is an important performance function required for antenna gain design. This paper aims to G/T analysis considering elevation angle change and the establishment of an antenna design procedure. For this purpose, the relationship between elevation angle and brightness temperature including rain attenuation was analyzed according to recommendation ITU-R P.372 radio noise. Next, an antenna was designed based on the analysis results and design procedure was verified by G/T measurement. Through this experiment, G/T according to elevation angle was confirmed, and the minimum antenna gain analysis and design procedure required in the system could be established.

• Journal of KIISE
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• v.41 no.12
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• pp.1058-1065
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• 2014

In order to assist user's who are in the process of executing a search, a query expansion method suggests keywords that are related to an input query. Recently, several studies have suggested keywords that are identified by finding domains using a clustering method over the documents that are retrieved. However, the clustering method is not relevant when presenting various domains because the number of clusters should be fixed. This paper proposes a method that suggests keywords by finding various domains related to the input queries by using a community detection algorithm. The proposed method extracts words from the top-30 documents of those that are retrieved and builds communities according to the word graph. Then, keywords representing each community are derived, and the represented keywords are used for the query expansion method. In order to evaluate the proposed method, we compared our results to those of two baseline searches performed by the Google search engine and keyword recommendation using TF-IDF in the search results. The results of the evaluation indicate that the proposed method outperforms the baseline with respect to diversity.

• Journal of Intelligence and Information Systems
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• v.7 no.1
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• pp.149-159
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• 2001

There have been lots of researches for providing a personalized service to a customer using one-to-one marketing and collaborative filtering techniques in E-Commerce. However, there are technical difficulties for providing the recommendation of products far users, which often involve high complexity of computation. In this paper, we have presented an integrated method of classification problem solving method and constraint based configuration techniques. This method can reduce a complexity of computation by classifying a solution domain space that has a higher complexity of composition. Thereafter, we have modeled customers constraints and the components of products to configure a complete system by passing it to constraint processing module in Constraint Satisfaction Problems. Constraint-based configuration uses the constraint propagation using the constraints of buyers and the constraints among PC components to configure a proper product for a customer. We have transformed and applied vector space modeling method in the field of information retrieval to consider a customer satisfaction in addition to the CSP. Finally, we have applied our system to test data fur evaluating a customers satisfaction and performance of the proposed system.

• Journal of Society of Preventive Korean Medicine
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• v.3 no.2
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• pp.1-23
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• 1999

The purpose of this paper is to survey the current status of service utilization in oriental medicine, to identify the determinants of consumers' decision in the service utilization, and then suggest policy implications for promoting the consumers' utilization. A multiple regression model was adopted to analyze the factors that influence consumer's decision in purchasing the oriental medical services. Data used in this research relied on National Survey Data conducted by Korea Institute of Health and Social Affairs, and sampling survey. The results could be summarized as follows.: 1. the number of visits to oriental medical institutions has shown an overall increase during the last decade since the inception of health insurance for oriental medical services. It still, however, revealed a relatively iow figure to western medical services. 2. the main factors, after controlling demographic variables, that determine consumers' selection between oriental medical services and western medical services are considered to be price, belief in effectiveness of services, waiting time for service. Implications for policy recommendation include 1. to reduce a barrier to service utilization by discounting dramatically the price of herb medicine, which is believed to be crucial in expanding market share, 2. to encourage consumer's belief in clinical effectiveness through a specialization in competitive services compared with wertern medicine, 3. to keep the affirmative image among consumers alive through an active participation of oriental medical doctors in community activities, 4 to change the health care system in favor of oriental medicine in the long run.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.25-31
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• 2006

The COMS (Communication, Ocean, and Meteorological Satellite) performing meteorological and ocean monitoring and providing communication service with meteorological, ocean and Ka-band payload in the geostationary orbit includes MODCS (Meteorological and Ocean Data Communication Subsystem) which provides transmitting the raw data collected by meteorological payload called MI (Meteorological Imager) and ocean payload named GOCI (Geostationary Ocean Color Imager) to the ground station and relaying the meteorological data processed on the ground to the end-user stations. MODCS comprises of two channels: SD channel which formats the raw data according to CCSDS recommendation, amplifies and transmits its signal to the ground station; MPDR channel which relays to the end-user stations the ground-processed meteorological data in the data format of LRIT/HRIT recommended by CGMS. This paper constructs the architecture of MODCS for transmitting and relating the observed data, and investigates that the key performance parameters have the required margin through the preliminary performance analyses.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.72-77
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• 2017

The Satellite Based Augmentation System (SBAS) broadcasts to users integrity and correction information for Global Navigation Satellite System (GNSS) such as GPS and GLONASS using geostationary orbit (GEO) satellites. In accordance with the recommendation of the International Civilian Aeronautical Organization (ICAO) to introduce SBAS until 2025, a Korean SBAS system development / construction project is underway with the Ministry of Land, Transport and Maritime Affairs. Korea Augmentation Satellite System (KASS) is a high precision GPS correction system which is composed of KASS Reference Station (KRS), KASS Processing Station (KPS), KASS Uplink Station (KUS), KASS Control Station (KCS) and GEO satellites. In this paper, we provided the conceptual design of the KASS uplink station, which is composed of the Signal Generator Section (SGS) and the Radio-Frequency Section (RFS), and interface between the KASS ground sector and the GEO satellite.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.243-252
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• 2012

This paper reviews the implementation of the STCW 78/95 in the Philippine MET including the effects of the revised 2010 Manila Amendments. It discusses the country's maritime environment and the structures, quality of maritime education in the country and the effects on the maritime human resource. Among the various resolutions adopted at the conference, the standards of training and certifications, and promoting skills and competency will be more emphasized in this report. These will be compared with the existing curriculum mandated by CHED and upgrade STCW trainings advised by MTC for maritime institutions. A brief comparison and analysis with other Asian countries' maritime training shall be offered. The recommendation pinpoints to the weaknesses of the present maritime regimes in certification and evaluation of maritime institutions. It concludes with the need to have mutually acceptable evaluation standards in view of developing a competent human resource for the future.

• The Journal of the Korea Contents Association
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• v.7 no.5
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• pp.138-145
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• 2007

Mobile network evolution and development of USN technologies introduce new business model based on context awareness. Cellular operators provide friend finding service using cell based location information and telematics service using GPS location information. Recently cellular operators provide yellow page service based cell based location information. In this paper, we develop mobile tour application on WIPI platform based on location information. Mobile tour information services provide the best information based on context awareness using user location information from LBS(Location Based Service) Platform, season, weather conditions, time from Web server, and personal preference information stored in database. Mobile tour information service application is developed on WIPI platform.