• The Journal of Korean Academy of Prosthodontics
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• v.26 no.1
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• pp.185-196
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• 1988

The purpose of this investigation was to analyze the color of natural teeth by means of the OFC-1001 DP colorimeter which could measure in Adams Coordinate System (L,a,b system). The subjects were the 164 persons (82 men and 82 women) ranged from the teen to the sixtieth who had come to infirmary of dental college, Chosun University. The colors of incisal third, middle third and cervical third of maxillary right incisor, maxillary right canine and maxillary right second premolar were examined after the teeth were cleaned, polished and dried. The data were analyzed statistically by means of SPSS (Statistical Package For the Social Science). The results were as follows. 1. The means of L(lightness), a (red chromaticity), b (yellow chromaticity) of all teeth were measured (Table 2,3,4). 2. The color of teeth was yellowish-gray or bluish-gray. 3. The L value and b value of the cervical third was greater than those of the incisal and middle third. 4. The L value of maxillary 2nd premolar was greater than those of maxillary incisor md maxillay canine. 5. The a & b values of maxillary canine were greater than those of maxillary incisor and maxillary 2nd premolar. 6. The average values of L,a,b of teeth between male and female were not significant. 7. The L values of teeth were decreasing and the b values of teeth were increasing as the age was increased, but there was no corelation between the a values and aging.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1581-1592
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• 2009

Recently, we can hear various kinds of music in everywhere and anytime. If a user wants to find the music which was heard before in a street or cafe, but he does not know the title of the music, it is difficult to find it. That is the limitation of previous retrieval system of music data. To overcome these problems, we research a method of content-based retrieval of music data based on the recorded humming, the part of recorded music and the played musical instrument. In this paper, we investigated previous content-based retrieval methods of papers, systems and patents. Based on that, we research a method of content-based retrieval of music data. That is, in case of using the recorded humming and music for query, we extract the frequency information from the recorded humming/music and the stored music data by using FFT. We use a MIDI file in case of query by the played musical instrument. And by using dynamic programming matching, the error caused by the disparity of length between the input source with the stored music data could be reduced.

• 연구논문집
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• s.27
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• pp.87-99
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• 1997

Present paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, relevant parameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. Compressor, combustor, turbine, and permanent-magnet generator will be mounted on a single high speed (82,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system's reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the given turbine inlet temperature, a rather conservative value of $1100^\circK$ was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at N/$N_{DP}$ = 0.53. Bleeding air for turbine stator cooling is omitted considering low TIT and for a simple geometric structure. Various engine performance simulations including, ambient temperature influence, surging at part load condition. Transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 80% approximately. Validation of present results are yet to be seen as the performance tests are scheduled by the end of 1998 for comparison.

• Journal of Fashion Business
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• v.17 no.6
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• pp.111-124
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• 2013

The purpose of this research was to conduct a comparison analysis of color in the characteristics and image of Korea/China/Japan airline uniforms. Research subjects for this research included 19 Korean, Chinese and Japanese airlines servicing the Incheon International Airport in South Korea. The analysis methods are based on the Munsell Color Order System and PCCS (Practical Color Coordinate System) tone classification in order to examine the color characteristics. For the color image analysis, the present research performed a positioning on Shigenobu Kobayashi's color images scale with adjectives in order to compare the resulting differences. As a result of the analysis, this research discovered the following; First, achromatic colors were found to be used most frequently in flight attendant uniforms of Korea/China/Japan. In Korean flight attendant uniforms, YR/Y, GY and B/PB/P; in Chinese, R/PB, RP, YR/Y/GY and BG/P; in Japanese, RP, R/P/PB and Y/BG were found in order. As for the main uniform colors, Korean flight attendant uniforms were found to be in the colors YR, and R/GY/B/P; Chinese flight attendant uniforms, R, PB, and P/B; and Japanese flight attendant uniforms, R, BG, B, RP and N. Second, Korean flight attendant uniforms used W and It most frequently; China flight attendant uniforms, W; and Japanese flight attendant uniforms, W and v. Regarding the main colors, Korean flight atteddant uniforms used lt/g and v/p; Chinese flight attendant uniforms, v, dp and s/d/dkg; and Japanese flight attendant uniforms, v/dkg and Bk. Third, after positioning each country's uniform color combination bars on the Kobayashi image scale, Korean flight attendant uniforms showed classic images along with casual/pretty/elegant/chic images; Chinese flight attendant uniforms displayed, casual images as well as, dynamic/gorgeous/chic/cool casual/dandy images; and finally, Japanese flight attendant uniforms converyed dandy images along with casual/gorgeous images. This research findings indicate that Korea/China/Japan airlines' flight attendant uniforms seek for differentiated image establishment by reflecting their own CIs and unique national cultures in the uniform color marketing.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3694-3701
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• 2000

Internet purchase is increasing according to the activation of Electronic Commerce. Currently, the hardware is main purchase items in the Electronic Commerce. The on-line purchase of digital product, that is electronic file type of product, has many merits such as, does not cost in logistics, is ease of searching the product, and is possible of 'Try and Buy' system. But, actually digital products have not been major product and Cause of its piracy problem. Therefore, the tchnology of digital rights management is focused within EC. The piracy problem of digital products comes from the lack of safety in DP license control technology. Current EC has no method to identify the object that has the right to use the digital product. The protecting of object change is impossible and the protection of hacking is not enough and EC has many problems in efficient license control because of the incompletion of EC structure. In this paper, we propose the design and implementation of on-line circulation system, which can activate on-line circulation of MP3 digital data product in EC, by using the new license control technology, that is Dynamic License Control technology.

• Tribology and Lubricants
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• v.35 no.4
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• pp.206-214
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• 2019

This study investigates alternative refrigerants and refrigerant oils as well as the tendency of protecting the global environment in view of automobile air-conditioning systems. Since decades, the R12 refrigerant is not used in automobile air-conditioners because of the ozone depletion potential (ODP) problem, and for the last 20 years, the ODP-free R134a refrigerant is leading the new automotive air-conditioning market. However, owing to its high global warming potential (GWP), the R134a refrigerant use in automobile air-conditioning system is also prohibited by law, and alternative refrigerants with a low GWP need to be proposed. Therefore, recently, the application of R1234yf, R152a, or other alternative refrigerants has started worldwide. By contrast, natural refrigerant R744 was introduced in the market several years ago by VDA (Verband Der Automobilindustrie), which is a German association in the automotive industry. This study also deals with refrigerant oils. For a long time, polyalkylene glycol (PAG) oil has been traditionally used with automobile air-conditioners, and polyolester (POE) oil is suitable for HEV, PHEV, and EV air-conditioning systems, where it is used by the electrically driven compressor owing to its excellent electrical insulation properties. Finally, PAG is an excellent lubricant for all the R134a, R152a, R1234yf, and R744 refrigerants, and has the advantage that it can be applied rapidly to alternative refrigerant air-conditioning systems.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.96-103
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• 2022

This paper presents the analysis of increasing the resolution of True-Time-Delay (TTD) by 0.5-bit for phased-array antenna system which is one of the Multiple-Input and Multiple Output (MIMO) technologies. For the analysis, a 5.5-bit True-Time Delay (TTD) integrated circuit is designed and analyzed in terms of beam steering performance. In order to increase the number of effective bits, the designed 5.5-bit TTD uses Single Pole Triple Throw (SP3T) and Double Pole Triple Throw (DP3T) switches, and this method can minimize the circuit area by inserting the minimum time delay of 0.5-bit. Furthermore, the circuit mostly maintains the performance of the circuit with the fully added bits. The idea of adding 0.5-bit is verified by analyzing the relation between the number of bits and array elements. The 5.5-bit TTD is designed using 0.18 ㎛ RF CMOS process and the estimated size of the designed circuit excluding the pad is 0.57×1.53 mm². In contrast to the conventional phase shifter which has distortion of scanning angle known as beam squint phenomenon, the proposed TTD circuit has constant time delays for all states across a wide frequency range of 4 - 20 GHz with minimized power consumption. The minimum time delay is designed to have 1.1 ps and 2.2 ps for the 0.5-bit option and the normal 1-bit option, respectively. A simulation for beam patterns where the 10 phased-array antenna is assumed at 10 GHz confirms that the 0.5-bit concept suppresses the pointing error and the relative power error by up to 1.5 degrees and 80 mW, respectively, compared to the conventional 5-bit TTD circuit.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.129-137
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• 2016

In the present study we verified performance of feed-forward control algorithm using short term prediction of ship motion information by taking advantage of developed numerical simulation model of FPSO motion. Up until now, various studies have been conducted about thrust control and allocation for dynamic positioning systems maintaining positions of ships or marine structures in diverse sea environmental conditions. In the existing studies, however, the dynamic positioning systems consist of only feedback control gains using a motion of vessel derived from environmental loads such as current, wind and wave. This study addresses dynamic positioning systems which have feedforward control gain derived from forecasted value of a motion of vessel occurred by current, wind and wave force. In this study, the future motion of vessel is forecasted via Brown's Exponential Smoothing after calculating the vessel motion via a selected mathematical model, and the control force for maintaining the position and heading angle of a vessel is decided by the feedback controller and the feedforward controller using PID theory and forecasted vessel motion respectively. For the allocation of thrusts, the Lagrange Multiplier Method is exploited. By constructing a simulation code for a dynamic positioning system of FPSO, the performance of feedforward control system which has feedback controller and feedforward controller was assessed. According to the result of this study, in case of using feedforward control system, it shows smaller maximum thrust power than using conventional feedback control system.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.419-424
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• 2004

Various radiation counters have been using to determine radioactivity of radwastes for disposal. A radiation counting system was set up using a radiation detector chosen in this study and its stability was investigated through the periodic determination of background and counting efficiencies in accordance with a quality control program to increase the confidence level. The average background level for the $\gamma$-spectrometer was 1.59 cps and the average counting level for the standard sample was 45248 Ops within $2{\sigma}$ confidence levels. The average alpha background level for the low background ${\alpha}{\beta}$ counting system was 0.31 cpm and the efficiency for alpha counting was 34.38%. The average beta background level for the ${\alpha}{\beta}$ counting system was 1,30 cpm and the efficiency for beta counting was 46.5%, The background level in the region of 3H and 14C for the liquid scintillation counting system was 2.52 and 3.31 cpm and the efficiency for alpha counting was 58.5 and 95.6%, respectively. The minimum detectable activity for the$\gamma$-spectrometer was found to be 3.2 Bq/$m\ell$ and 3.8 Bq/$m\ell$ for the liquid scintillation counter, and 20.5 and 23.0 Bq/$m\ell$, respectively for the $\alpha$ and $\beta$ counting system.

• Maritime Security
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• v.4 no.1
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• pp.115-138
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• 2022

The Korean military is preparing for successful manpower reduction using advanced science and technology, in addition to carrying out the initiative of the Defense Innovation 4.0. Accordingly, studies on core technologies related to defense reform have been conducted both internally and externally in the military, and the corresponding results have also been applied. Nevertheless, compared to the development of such technologies, it is considered necessary to have more preparation for the policies related to the operation of the newly introduced equipment. As for the placement of personnel and the organization of time in service (TIS) with respect to the operation of surveillance equipment, there has been a tendency to sustain the conventional practice. Therefore, this study intends to suggest the schemes for facilitating policy improvements in the operation of manpower and security regulations in the field of information for the purpose of introducing a successful next-generation coastal guard system. To do this, the approach of this study was focused on the policies for the operation of the guard system. This is in contrast to previous studies that centered on its equipment and technologies. In addition, how to efficiently operate the guard system was also studied in view of cognitive science by deriving the most efficient time for a person to execute surveillance through the monitor based on the previous studies.