• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.623-626
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• 2005

The technique of developing Digital Contents have still not be a standard, and it is cause some problems in the Digital Contents's creating, circulation and consumption, So solve the problem, MPEG suggest MPEG-21 framework. In the standard, The IPMP take charge of the Digital Contents's protection and management, and also it is the same as the rights expression language REL and the dictionary defining the word of REL. But. the study of the IPMP is later than the study of REL and RDD, such as the other study of the MPEG-21 standard. So, there is few system based REL and RDD. In this paper, in order to management and protect contents right. So facing the latest standard, we designed and implementation the Tool Server and the License Server based on REL/RDD.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.141-144
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• 2006

The deviations in the injection orbital parameters, resulting from launcher dispersions, need to be estimated and used for autonomous satellite operations. For the proposed small satellite mission of the university there will be two GPS receivers onboard the satellite to provide the instantaneous orbital state to the onboard data handling system. In order to meet the power requirements, the satellite will be sun-tracking whenever there is no imaging operation. For imaging activities, the satellite will be maneuvered to nadir-pointing mode. Due to such different modes of orientation the geometry for the GPS receivers will not be favorable at all times and there will be instances of poor geometry resulting in no output from the GPS receivers. Onboard the satellite, the orbital information should be continuously available for autonomous switching on/off of various subsystems. The paper presents the strategies to make use of small arcs of data from GPS receivers to compute the mean orbital parameters and use the updated orbital parameters to calculate the position and velocity whenever the same is not available from GPS receiver. Thus the navigation message from the GPS receiver, namely the position vector in Earth-Centered-Earth-Fixed (ECEF) frame, is used as measurements. As for estimation, two techniques - (1) batch least squares method, and (2) Kalman Filter method are used for orbit estimation (in real time). The performance of the onboard orbit estimation has been assessed based on hardware based multi-channel GPS Signal simulator. The results indicate good converge even with short arcs of data as the GPS navigation data are generally very accurate and the data rate is also fast (typically 1Hz).

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.3
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• pp.211-219
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• 2014

This paper proposes a low voltage high current LLC resonant converter for Green PC. Green PC is composed of a lot of blade PCs, and it is a centralized system to manage them in computer center. Green PC should require that its power supplies have several characteristics such as low output voltage, high output current, and high power conversion efficiency. Conventional PSFB (Phase Shift Full Bridge) converter is usually used as DC/DC converter for computer power supply because it has high power conversion efficiency thanks to ZVS (Zero Voltage Switching) operation under middle and high load conditions. However, this converter has some problems such as large switching noise and limitation of ZVS operation under light load condition. In order to improve the performance of power supply for Green PC, a new power supply using popular high efficiency LLC resonant converter for low voltage and high current application is proposed in this paper. The proposed power supply has ZVS capability over the entire load range, thus resulting in good efficiency and high switching frequency. Experimental results verify the performance of the proposed power supply for Green PC using 2[kW] (19[V], 105[A]) rated prototype converter.

• Journal of Information Management
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• v.25 no.2
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• pp.31-60
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• 1994

General branches of science and engineering now enjoy being substantially repleted in their databases. However, comparing the databases of such branches with chemistry or medical science and pharmacology, the strata do not seem to be fully equipped yet. As a matter of fact, the variety of such databases in practical application is still somewhat limited. Moreover, these databases are, with a few exceptions, prepared abroad. In this paper varieties and features of databases now available on the market for each database service system, as well as crucial points for practical use are introduced. At present, it is focussed more or less on the application of bibliographical information. Yet, it would be inevitable to equip them with factual data in order to increase the efficiency of research and development activities. Of course, it is still not easy to solve problems for better profitability and higher technical achievement. The author wishes to emphasize the necessity to fully equip the commercial factual database for said branches as quickly as possible.

• Journal of Elementary Mathematics Education in Korea
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• v.24 no.2
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• pp.207-229
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• 2020

The study examined on the general educational system, the structure of the document of mathematical curriculum, and the characteristics of the achievement standards written in the document of France in order to compare with Korean primary mathematics education. French pupils learn about 5% more hours than Korean sixth grade pupils, and French document of mathematical curriculum describes the contents included in the documents more concretely than us. There were a large differences in the subjects both of mixed calculations and division of fractions in the area of number and operations. The study proposed the necessity for researches on the concrete description of the document of mathematical curriculum, more concrete examples to use to teach pupils on the viewpoints of school mathematics, and the learning sequences and methods of the division of fractional numbers. At last we proposed to need rethink of the importances and teaching methods of calculations.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.369-378
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• 2000

The purpose of this study is to developed high-efficient rotary tillage system for a power tiller by improving the rotary blade. A kind of the rotary blade with single-edged blade(DS) was developed that requires lower tillage energy than conventional double-edged blade(CD) on the design theory for Japanese rotary blade. In order to find out the tillage characteristics between the single-edged blade and the double-edged blade for power tiller, experiments were performed in soil-bins which were filled up clay loam, loam and sandy loam, and then analyzed the effects of the factors such as soil texture, travelling speed, rotational speed, and tillage depth to each of the blades. And field tests were carried out to compare tillage performances of the two blades using rotary cultivator driven by conventional power tiller. The results of this study were summarized as follows; 1) On the soil bin experiment, it was found that tillage torque of the single-edged blade was less than the ones of the double-edged blade. The decreasing ratios of maximum tillage torque of the single-edged blade to the ones of the double-edged blade were 1 to 8% at clay loam, 5 to 20% at loam and 9 to 31% at sandy loam, respectively. 2) By the field tests, that the tillage performances with the single-edged blade compared with the double-edged blade was improved about 19% in field capacity, about 34% in fuel consumption, and 12.5% in soil breaking ratio. Furthermore, the fluctuation of engine speed, the variation of exhaust gas temperature, and the amount of soil clogging on the blade and straw wound on the rotary shaft showed lower values with the developed blade than the conventional blade. So, it may be concluded that tillage performance by the developed single-edged blade was improved compared with the one by the conventional double-edged blade.

• Journal of Biosystems Engineering
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• v.27 no.1
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• pp.11-18
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• 2002

One of the major obstructing factors against managing dairy farm in Korea has been a shortage of roughage supply, which resulted in excessive abuse of concentrate feed. In order to solve this problem, production of the wrap silage by the winter cereal forages raised in the fallow paddy field is strongly recommended in Korea. The main objective is to develop a tractor attached round bale wrapper which can process the silage by wrapping the round bales with thin plastic films. This is the first half of the study which is divided by two parts. In this first part, bale wrapping process was analyzed, and based on this results the followings were designed, developed and tested. 1. Bale wrapper which haying the maximum capacity of 1 ton bale with various functions such as loading, wrapping, discharging the round bales and supplying and cutting wrap films was designed. 2. An actuator and its hydraulic circuit of each process were developed and tested. 3. Also, the variations of hydraulic pressure and engine speed were investigated by operating bale wrapper developed. In this test, maximum pressure of the hydraulic circuit for the bale wrapping was 130 kg/㎠ when it raised the bale, which was quite below the relief pressure of 170 kg/㎠ of hydraulic circuit. In the engine speed test, speed drop was 20∼67 rpm, which meant that there was no over-load operation. Therefore, the experiment proved that developed hydraulic circuit and mechanism is stable in bale wrapping operation

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.205-211
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• 2013

The swine is one of the most widespread mammalian throughout the whole world. Presently, many studies concerning microsatellites in swine, especially domestic pigs, have been carried out in order to investigate general diversity patterns among either populations or breeds. Until now, a lot of time and effort spend into a single PCR method. But simple and more rapid multiplex PCR methods have been developed. The purpose of this study is to develop a robust set of microsatellites markers (MS marker) for traceability and individual identification. Using multiplex-PCR method with 23 MS marker divided 2 set, various alleles occurring to 5 swine breed (Berkshire, Landrace, Yorkshire, Duroc and Korea native pig) used markers to determine allele frequency and heterozygosity. MS marker found 4 alleles at SW403, S0227, SWR414, SW1041 and SW1377. The most were found 10 alleles at SW1920. Heterozygosity represented the lowest value of 0.102 at SWR414 and highest value of 0.861 at SW1920. So, it was recognized appropriate allele frequency for individual identification in swine. Using multiplex-PCR method, MS markers used to determine individual identification biomarker and breed-specific marker for faster, more accurate and lower analysis cost. Based on this result, a scientific basis was established to the existing pedigree data by applying genetics additionally. Swine traceability is expected to be very useful system and be conducted nationwide in future.

• Journal of Satellite, Information and Communications
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• v.6 no.2
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• pp.15-19
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• 2011

The T-DMB(Terrestrial Digital Multimedia Broadcasting) which was developed by the convergence of digital broadcasting technology and communication technology provides us with very good quality of music like CD, and provides TV services in a super express train like the KTX whose velocity is over 300 Km per hour. The T-DMB is diffusing toward the world as a technology which is be able to provide the various convergent services of broadcasting and communication through mobile phone, PDA, dedicated terminal, and so on. A business model needed for the diffusion of the T-DMB toward the world was established and utilized to expand the T-DMB into Vietnam in the paper. In addition, this paper describes not only some predicting methods for the technological valuation of the T-DMB Total Solution, but also a case study on the marketing related to establishing the T-DMB system in order to provide the paid services in Vietnam. Finally, A couple of business models needed to globally expand the T-DMB have been provided.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.2
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• pp.87-92
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• 2009

Remote detecting system for a radiation contamination using a plastic scintillator and an optical fiber was developed. Using a commercially available silica optical fiber and a plastic scintillator, we tested then for a real possibility as a remote monitoring detector. Also, a plastic scintillator was developed by itself, and evaluated as a radiation sensor. The plastic scintillator was made of epoxy resin, a hardener and an organic scintillation material. The mixture rate of the epoxy resin, hardener and organic scintillator was fixed by using their emission spectrum, transmittance, intensity etc. In this study, in order to decrease the light loss of an incomplete connection between an optical fiber and a scintillator, the optical fiber was inserted into the scintillator during the fabrication process. The senor used a plastic optical fiber and was estimated for its detection efficiency by an optic fiber's geometric factor.