• Journal of the Ergonomics Society of Korea
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• v.28 no.2
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• pp.35-55
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• 2009

The purpose of this study was to analyze the somatotypes of women in the early 20's, which were likely to deform due to bad posture in growth period. Accordingly, bodies of women aged 20 to 24, whose growth stopped, were measured directly and indirectly, and factors related to body shapes were extracted, body shapes were categorized based on the data, and the characteristics of each body shape were analyzed. As a result, 10 factors related to body shapes were extracted in the factor analysis, and body shapes were categorized into 6 types. Type 1 was the volume of body that was big and the longest; and the general frame was large. The straight body shape with small back protrusion; the shoulder is relatively thick and the width of the shoulder was normal. Type 2 was the volume of body that was the biggest and the upper body was the longest; the general frame was of average height. The forward body shape with the back flat; the shoulder was very thick, wide, and serious leaning forward. Type 3 was a body that was thin and the shortest. The sway-back body shape with big curvature at the back; the shoulder was thin, narrow, and straight. Type 4 was a body that was short stature, and the general frame was of average build. The forward body shape with the most serious back protrusion; the shoulder was normally thick, narrow, and straight. Type 5 was a group with small body, and the lower body and general frame are long. The sway-back body shape with protrusion at the upper shoulder and the sides leaning backward; the shoulder was thin, wide, and leaning forward. Type 6 was a thin and short body; and the general frame was small. The lean-back body shape with the smallest back protrusion and leaning backward; the shoulder was thin, narrow, and leaning backward. Characteristics of the classified body shapes can be used in producing ready-made clothes, and it is hoped that there will be follow-up studies on clothing pattern design and production based on this result.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.559-562
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• 2000

The problem of noise generation due to PWM switched-mode power converter has been widely noticed from the viewpoint of Electromagnetic Interference(EMI). Many kings of topologies for resonant converters have been developed both to overcome this noise problem and to attain high power efficiency. It is reported in references that resonant converters which are derived from PWM converter using resonant switch show much lower noise characteristics than PWM converter, and that current-mode resonant converter is more sensitive to stored charge in rectifying diode than voltage-mode counterpart concerning surge generation at diode’s turn-off. On the other hand, above mentioned resonant converters have defect of high-voltage stress on semiconductor switch and complicated circuit configuration. Hence, the simplified Forward-type resonant converter has been proposed and investigated due to its prominent features of simplicity of circuit configuration, low voltage stress and high stability. However, its noise characteristics still remain unknown. The purpose of this paper is to study quantitatively the noise characteristics of this simplified Forward-type resonant converter by experiment and analysis. The influence of parasitic elements and stored charge in rectifying diode on noise generation has been clarified.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.8
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• pp.1468-1484
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• 1992

In the present paper forward projection is proposed as a new approach to determine the preform shape in rib-web type forging. In the forward projection technique an optimal billet is determined by applying some mathematical relationship between geometrical trials in the initial billet shape and the final products. In forward projection a volume difference between the desired product shape and the final computed shape obtained by the rigid-plastic finite element method is used as a measure of incomplete filling of working material in the die. At first linear inter-/extrapolation is employed to find a proper trial shape for the initial billet and the method is successfully applied to some cases of different aspect ratios of the initial billet. However, when the initial guesses are not sufficiently near the optimal value linear inter-/extrapolation does not render complete die filling. For more general application, a fuzzy system is used in the forward projection technique in order to determine the initial billet shape for rib-web type forging. It has been thus shown that the fuzzy system is more reliable for the preform design in the rib-web type forging process.

• The Journal of Korean Physical Therapy
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• v.21 no.4
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• pp.9-16
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• 2009

Purpose: This study was done to assess the effect of changes in forward head posture (FHP), neck mobility and headache clinical parameters on episodic tension-type headache (ETTH) and chronic tension-type headache (CTTH) who did craniocervial exercises. Methods: Twelve CTTH subjects and twelve ETTH subjects were studied. Side-view pictures of subjects were taken in both sitting and standing positions, in order to assess FHP by measuring the craniovertebral angle. Cervical range of motion (CROM) was employed to measure cervical mobility. A headache diary was kept to assess headache intensity, frequency, and duration. All subjects did three types of craniocervical exercise over 8 weeks. Measurements were done at pre-treatment, and at 4 and 8 weeks post-treatment. Results: Forward head posture and headache-related clinical parameters showed a significant improvement after craniocervical exercise (p<0.05). Flexion/extension and left/right rotation of CROM was significantly increased after the intervention (p<0.05), whereas changes in left/right bending did not reach statistical significance. Conclusion: This study indicates that craniocervical exercise may be effective in the management of tension-type headache.

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.71-77
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• 2009

Purpose: This study assessed the differences in the forward head posture (FHP), cervical range of motion, and headache clinical parameters in episodic tension-type headache (ETTH) subjects, chronic tension-type headache (CTTH) subjects, and healthy controls (university students). Methods: Fifteen CTTH subjects, 15 ETTH subjects and 15 controls without headache were examined. Side-view images of each group were taken in both the sitting and standing positions, in order to assess the FHP by measuring the craniovertebral angle. The CROM was used to measure the cervical range of motion. A headache diary was kept for 4 weeks to assess the headache intensity, frequency, and duration. Results: The craniovertebral angle was smaller, ie, there was a greater FHP, in the CTTH and ETTH subjects than in the healthy controls in both the sitting and standing positions (p<0.05). The CTTH and ETTH subjects showed a lower cervical range of motion than the healthy controls in the total range of motion as well as in the half-cycles (p<0.05). Conclusion: The increased FHP and decreased cervical range of motion might be a contributing factor in the initiation of tension-type headache.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.7
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• pp.335-342
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• 2003

This paper presents a forward type high voltage pulse power supply for high voltage small current, which can be designed as a simple circuit configuration and managed easily using Power-MOSFET in the view of commercialization. According to the switching frequency, coupling factor(k) and duty ratio(D), the Principle of basic operation and the characteristics of the proposed pulse power supply are estimated. Simulation results have demonstrated the feasibility of the proposed pulse power supply. Also experimental results are presented to verify theoretical discussion with a lamp type ozonizer as a load. For studying the application at the part of environment of water, When ozonizer gas reacts with a colon bacillus, the sterilization characteristics of a colon bacillus according to the ozone concentration and response time have been investigated. This proposed pulse power supply will be able to be practically used as a pulse power supply in various environment improvement facilities like sterilization of colon bacillus, deodorization, and Nox gas elimination.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2792-2810
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• 2017

Forward-secure signature is a specific type of signature, which can mitigate the damage caused by the signing key exposure. Most of the existing forward-secure (identity-based) signature schemes can update users' secret keys at each time period, achieve the existential unforgeability, and resist against classical computer attacks. In this paper, we first revisit the framework of forward-secure identity-based signatures, and aim at supporting flexible key update at multi time period. Then we propose a post-quantum forward-secure identity-based signature scheme from lattices and use the basis delegation technique to provide flexible key update. Finally, we prove that the proposed scheme is strongly unforgeable under the short integer solution (SIS) hardness assumption in the random oracle model.

• Journal of Wind Energy
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• v.2 no.1
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• pp.82-89
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• 2011

his dissertation is on power control system for MW-class wind turbine. Especially, the control purpose is reduction in electrical power and rotor speed. The base control structure is power curve tracking control using variable speed variable pitch operational type. For the reduction of fluctuations, more control algorithm is needed in above rated wind conditions. Because general pitch control system is low dynamic response as compared with the wind speed change. So, this paper introduces about the pitch feed forward control to minimize fluctuations of the electrical power and rotor speed. To maintain rated electrical power, the algorithm of feed forward control adds feed forward pitch amount to the pitch command of power curve tracking control. The effectiveness of the feed forward control is verified through the simulation.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1461-1468
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• 2000

Objective : The aim of this study is to evaluate clinical outcome of anterior screw fixation for type II odontoid fractures for the prliematim of atlanatoaxial mobility. Methods : Between 1995 and 1999, we treated 15 cases of type II odontoid fractures by anterior screw fixation among 44 cases of odontoid fractures. Thece included 14 males and 1 female aged from 23 to 63 years, with a mean age of 39.7 years. The causes of trauma were traffic accident in 13 cases, slip down in 1 and fall down in 1. The fracture type was type II-P in 7 cases, type II-A in 3, type II-N in 2 and type II-A and P in 3. The fracture line was oblique downward and backward in 6 cases, oblique downward and forward in 3 and horizontally in 6. The range of follow up was 4 to 47 months(mean 26.5 months). Results : Adequate reduction and fixation were obtained in 12 cases. Three cases in which fracture type and line were type II-A and oblique downward forward were failed, so posterior transarticular screw fixation was performed. All except 3 failed cases had adequate cervical movement and stability. There were no operative mortality nor morbidity. Conclusion : Anterior screw fixation provides the best anatomical and functional results for type II odontoid fracture with intact transverse ligament when fracture line is horizontal or oblique downward and backward. But it is limited when fracture line is oblique downward and forward.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.329-330
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• 2016

This paper deals with stability of active EMI filter. Feed-forward type voltage-sensing voltage-injection (VSVI) AEF is best topology when considering the filter size and leakage current. But it is not studied in stability. Therefore, the detailed and simplified transfer function is derived and it is used to analyze stability. The experimental results are provided to verify the effectiveness of the analysis.