• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.193-196
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• 2003

For a power source of usual electronic devices such as PDA, smart phone, UPS and electric vehicle, the battery made of serially connected multiple cells is generally used. In this case, if there are some unbalanced among cell voltages, the total lifetime and the total capacity of the battery are limited to a lower value. To maintain a balanced condition in cells, an effective method of regulating the cell voltage in indispensable. In this paper introduced a method for battery balancing system using dissipation in the resistance.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.485-486
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• 2010

FPS(Filament Power Supply), one of the KSTAR NBI (Neutral Beam Injections) is implemented by full-bridge DC/DC converter. NBI heating device for KSTAR(1.5MW) is developed for heating an ion source of plasma in KSTAR tokmak. The full-bridge DC/DC converter is applied to FPS for isolation with input and output. And FPS is operated with PWM control method which is the most usual method. In this paper, NBI FPS of 4.8kW is simulated by using the PSIM 6.0. And the full-bridge DC/DC converter using IGBTs is fabricated to demonstrate it. The processor DSP 28335 is implemented for digital control.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.3
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• pp.244-252
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• 1992

This paper describes a reactive power compensator using current-source delta modulation converter, which compensates the reactive power in the ac sides of 3-phase rectifier. In the conventional current control methods for the current-type reactive power compensators, it is usual to compare the reactive reference current signal with the triangular wave and hence to generate the ON-OFF signals for the reactive power compensator. To improve the response as well as the control capability, the delta modulated current control technique is used in this paper. As a result, the input power factor is improved close to unity and both simulation and experimental results show good compensating performances.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1145-1151
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• 2007

In this paper, vibration sources of an electric forklift are identified and the forklift vibrations are reduced by structural modification. For vibration identification, vibration signals are measured by an accelerometer when the forklift is moving. These signals are presented in a waterfall plot in order to find the dependency of frequency components on the forklift speed. It is found that main vibration source is tire pattern excitation. From some experiments and finite element analyses, it is also found that resonances occur because the natural frequencies of the forklift exist in usual driving speed range. To shift the natural frequencies outside the driving speed range, the connection parts between main body and loader are modified to increase stiffness. It is verified that considerable amount of vibration are reduced by the structural modification.

• Korean Journal of Health Education and Promotion
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• v.15 no.1
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• pp.165-178
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• 1998

The purpose of this explanatory study was to provide baseline information on the secondary prevention health behavior of cervical cancer in Korea which was related to the utilization of the Papanicolaou (Pap) smear screening test. The secondary data from the 1992 Korean Health Behavior Survey was used for analysis in order to determine sociodemographic profiles and the predictor variables. The sample analyzed for this study contained 1,489 Korean women residing in Korea aged 20-59 selected by multi-stage sampling method from the 1990 Korean census. Univariate, bivariate, and logistic regression analysis were performed to produce the findings of this study. Only 27.9% of the study sample had had a Pap test in 1992. It was found that the relative sociodemographic profiles of the Pap test between users and non-users were distinctive. The predictors variables were age, marital status, educational status, usual source of care, perceived household economic status, health check-up, and presence of chronic diseases

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.191-194
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• 2002

We analyzed radiation characteristics of dipole antenna in a lossy 9round with conducting object located above ground. Electric field integral equation is used to solve the problem. In this integral equation, GPOF(Generalized Pencil of Function) method is applied to derive the closed form of the electric field due to a current source. Surface current on a conductor is expanded with a well-known vector triangle basis function. The singular integration of a triangle patch is transformed to the non-singular integration by Duffy's method. This transformed non-singular integration is easily calculated by using one-dimensional Gaussian quadrature rule, instead of usual closed form evaluation.

• The Journal of Information Systems
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• v.14 no.3
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• pp.9-16
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• 2005

In this paper, the performance of the WebService architecture for QoS guaranteed connection provisioning in inter-AS domain networks has been measured and analyzed for service publish/inquiry, collection of NMSs ASBR details, source routing by ingress NMS in constraint based routing and connection establishment. From the analysis, it has been found that, the connection between inter-AS domain networks can be established within the usual time limits of 3 seconds by the Web Service architecture. Since no standard solutions have been implemented in Interdomain QoS provisioning, this performance analysis assures Web Service architecture as a promising solution and can be easily implemented in the early stages of MPLS network employment.

• The Korean Journal of Ceramics
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• v.6 no.4
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• pp.370-379
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• 2000

Simple ways to build up mixed-metal molecules which can act as potential single-source precursors to multimetallic oxides are reviewed. Emphasis is given to Lewis acid-base reactions between metal alkoxides M(OR)/sub n/, and between metal alkoxides and more accessible oxide precursors, carboxylates M(O₂CR)/sub n/ and β-diketonates M(β-dik)/sub n/. Characterization of the precursors is achieved in the solid state (single crystal X-ray diffraction, FT-IR) and by multinuclear NMR in solution. The reactions proceed toward the formation of aggregates in which the different metals display their usual coordinations numbers, often six for transition metals, as shown. Strategies for fixing the stoichiometry between the metals are developed. The reactivity of the MM species (dissociation, effects of chemical modifiers, of other metallic species, hydrolytic or non-hydrolytic condensation, etc.) will be indicated. Transformations into oxides are illustrated on precursors for titanates or niobates.

• Journal of Nutrition and Health
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• v.36 no.9
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• pp.950-959
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• 2003

To assess zinc status by dietary intake and urinary excretion of preschool children in Busan and to evaluate the relationship of intakes of food and nutrient with urinary zinc excretion, zinc food frequencies of 40 common foods affecting intakes of zinc by food fequency method, nutrient intake by 24hr recall and 24hr urinary zinc excretion were measured with 97 preschool children. The mean zinc intake was 4.29 mg and 43.0% of RDA. The mean zinc intake per 1,000 kcal was 3.09 mg.97.9％ of subjects had zinc intake less than 75％ of RDA. Grains food group was the primary source of zinc intake and supplied 38.9% of the total daily zinc intake. Altogether, plant food products supplied 49.7% of zinc intake. The mean urinary zinc excretion and zinc excretion per gram of creatinine were 0.19 mg and 1.00 mg respectively. The urinary zinc excretion showed positive significant correlations with height and weight (p < 0.05, p < 0.05) , urine volume and urinary creatinine excretion (p < 0.05, p < 0.001) , urinary zinc excretion per creatinine (p < 0.001) , urinary zinc excretion per weight (p < 0.001) , intakes of energy and carbohydrate (p < 0.05, p < 0.01) and usual intake of zinc from eggs food group (p < 0.05) . In conclusion, these results show that the zinc intake of preschool children is low and that sources of dietary zinc are mainly plant foods, suggesting low bioavailability. So nutritional education is needed in order to inc-rease usual intake of animal food group. Interpretation of urinary zinc excretion data is complicated by current uncertainty about "normal" zinc level at this age group. Further studies are needed to obtain extensive data on urinary zinc excretion for this age group.age group.

• Journal of Nutrition and Health
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• v.35 no.9
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• pp.970-981
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• 2002

To assess riboflavin status by dietary intake and urinary excretion of preschool children in Busan and to evaluate the relationship of intakes of food and nutrient with urinary riboflavin excretion, riboflavin food frequencies of 40 common foods affecting intakes of riboflavin by food fequency method, nutrient intake by 24hr recall and 24hr urinary riboflavin excretion were measured with 97 preschool children. The mean riboflavin intake was 0.90 mg and above RDA. Dairy group was the primary source of riboflavin intake and provided 44.8% of the total daily riboflavin intake. The mean urinary riboflavin excretion and riboflavin excretion per gram of creatinine were 395.21$\mu\textrm{g}$ and 2110.41$\mu\textrm{g}$ respectively, The mean riboflavin intake (p<0.01, p<0.01), riboflavin density (p <0.001, p<0.001) and urinary riboflavin excretion per gram of creatinine (p<0.05, p<0.05) were significantly low with the two patterns of food group intake where dairy group was omitted (GMVFDS = 111101, consuming no dairy group and GMVFDS=l11001, consuming no fruit and dairy groups). On the basis of urinary riboflavin excretion per gram of creatinine, 14.3% of subjects in the group aged 1 to 3 and 18.2% of subjects in the group aged 4 to 6 were at risk of deficiency respectively. The urinary riboflavin excretion per gram of creatinine showed positive significant correlations with usual intakes of riboflavin from food groups of dairy (p<0.05), meat (p<0.05) and animal (p<0.05). So nutritional education is needed in order to consume dairy food group daily and to increase usual intake of animal food group including meat.(Korean J Nutrition 35(9) : 970~981, 2002)