• The korean journal of orthodontics
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• v.15 no.2
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• pp.313-325
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• 1985

This study was performed to establish the cephalometric standards and growth change of Korean teen-age group by Ricketts analysis. A roentgenocephalometric study was made from 365 subjects, that consist of 159 males, 206 females with normal occlusion, acceptable profile and no history of orthodontic and prosthodontic treatment. The results were as follows: 1. The tables of means, standard deviation from measured values were made. (male, female, both sex). 2. The tables of regression equations from measured values were made to establish the relationship between age and each item. (male, female, both sex). 3. All linear measurements of each item in male were greater than in females. 4. Items which show more linear than any other items were condyle axis, facial axis length, corpus length and upper molar position.

• Publications of The Korean Astronomical Society
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• v.14 no.2
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• pp.129-137
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• 1999

We arranged ancient Korean calendar during Koryo dynasty (A.D. 918-1392) according to Julian calendar. We used two representative history books, Koryo-sa (高麗史) and Koryo-sa Jeolyo (高麗史節要), which contain thea stronomical and the historical records chronologically. We found all 19,727 ganji dates(日辰) and 102 misrecoreded ganji dates in two books. Most of the data are arranged based on those two books, and doubtful data are identified using the eclipse, historical events and lunar phase calculations etc. Although Korea, China, and Japan were using basically the same calendar since ancient times, their calendars show some significant disagreement. We found that arranged chronological tables during Koryo dynasty were, in some cases, different from those of China and Japan.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.163-172
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• 1998

The design fundamentals of the shaking tables are briefly discussed. In order to understand the recent trends in development of the shaking tables, the characteristics and performances of the major seismic testing facilities are investigated. The international standards related to the vibration tests using shaking table are also overviewed. The newly designed multipurpose biaxial shaking table of Hyundai Heavy Industries, Co., Ltd. is introduced. It has the capabilities to perform the vibration, shock and seismic qualification tests in two simultaneous and independent directions (vertical and horizontal directions). Since the shaking table adapts four extremely stiff torque instead of much more expensive hydraulic actuators, these tubes can restrain two undesired rotational motions. Regarding the manufacturing and maintenance costs, two system is more economical since it has only two hydraulic actuators unlike others.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.103-104
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• 2013

As a result of experimenting 6 loading combustibles in domestic residential facilities by using Furniture Calorimeter, values of 2,391.26kW were appeared from sofas, 1,891.80kW from drawers, 1,778.95kW from mattress, 1,104kW from chairs, 291kW from tables, and 135.09kW from TV. Also, if applying α value of fire growing rate by classifying fire- growing speeds at NFPA 72 (National Fire Alarm Code 2007, Annex B), mattress can be defined as Ultra-Fast, sofa and drawers Fast, TV Slow, tables Slow, and chairs Medium.

• Journal of the Korean Data and Information Science Society
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• v.17 no.3
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• pp.919-925
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• 2006

Maximum likelihood estimate(MLE) is obtained from the partial log-likelihood function for the cell probabilities of two way incomplete contingency tables proposed by Chen and Fienberg(1974). The partial log-likelihood function is modified by adding lagrangian multiplier that constraints can be incorporated with. Variances of MLE estimators of population proportions are derived from the matrix of second derivatives of the loglikelihood with respect to cell probabilities. Simulation results, when data are missing at random, reveal that Complete-case(CC) analysis produces biased estimates of joint probabilities under MAR and less efficient than either MLE or MI. MLE and MI provides consistent results under either the MAR situation. MLE provides more efficient estimates of population proportions than either multiple imputation(MI) based on data augmentation or complete case analysis. The standard errors of MLE from the proposed method using lagrangian multiplier are valid and have less variation than the standard errors from MI and CC.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.6
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• pp.453-456
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• 2004

Due to the bandwidth and storage limitations medical images are needed to be compressed before transmission and storage. DICOM (Digital Imaging and Communications in Medicine) specification, which is the medical images standard, provides a mechanism for supporting the use of JPEG still image compression standard. In this paper, we explain a method for compressing medical images by PEG standard and propose two methods for JPEG compression. First, because medical images differ from natural images in optical feature, we propose a method to design adaptively the quantization table using spectrum analysis. Second, because medical images have higher pixel depth than natural images do, we propose a method to design Huffman table which considers the probability distribution feature of symbols. Simulation results show the improved performance compared to the quantization table and the adjusted Huffman table of JPEG standard.

• Journal of Power Electronics
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• v.15 no.1
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• pp.106-115
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• 2015

This paper proposes a novel direct power control (DPC) strategy for neutral-point-clamped (NPC) three-level rectifiers, to directly control the active power, the reactive power and the neutral point potential of the rectifiers by referring to three pre-calculated vector influence tables and minimizing an objective function. In the three vector influence tables, the influences of different voltage vectors on the active power, the reactive power and the neutral-point potential are shown explicitly. A conceptual description and control algorithm of the proposed controller are presented in this paper. Then, numerical simulations and experiments are carried out to validate the proposed method. Both the simulation and experimental results show that good performances during both the steady-state and transient operating conditions are achieved. As a result, the proposed strategy has been proven to be effective for NPC three-level rectifiers.

• Journal of Korean Institute of Industrial Engineers
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• v.16 no.1
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• pp.1-15
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• 1990

An AQL type variables sampling system with switching rules is proposed. Comparative studies of existing variables sampling standards - MIL-STD-414, ANSI Z1.9, ISO 3951, and BS 6002 - are made, and simulation studies on switching procedures are conducted. Based on comparative and simulation studies, a variables sampling standard for Korean industry is proposed. The master sampling tables of the proposed standard are taken from the variables standard ANSI Z 1. 9 and the switching rules are matched to the attributes standard KS A 3109 to enable us to move between the proposed variables standard and KS A 3109. Composite OC and ASN curves of the proposed standard are calculated for selected combinations of lot sizes and AQL's and they are compared with those of ANSI Z1.9.

• IE interfaces
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• v.24 no.1
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• pp.71-77
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• 2011

Design works consist of essential works and subsidiary works. Essential design works means designing creative ideas and productive ideas, while subsidiary design works means helping essential works those are making data tables and specification sheets, checking CAD data's integrity. Subsidiary design works forms the bulk of the whole design process and affects the time limit of delivery. Therefore we propose the automatic data matching system for CAD data's integrity. Proposed system is automatic system supporting subsidiary design works. The data matching system consists of three parts; 1) automatic generation of data tables 2) supporting module for checking CAD data's integrity between Drawings 3) automatic generation of spec. sheets. Developed system was tested in LCD equipment manufacture company and was found to be useful system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.120-124
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• 2006

We present two techniques based on lookup tables to reduce complexity of the well-known Schnorr-Euchner (SE) sphere decoder (SD) without introducing performance degradation. By the aid of lookup tables, the computational loads caused by the SE enumeration and decision feedback are reduced at the cost of higher storage capacity. Simulation results are provided to verify performance and complexity of the proposed decoders.