• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.70-77
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• 2010

This paper presents the current and speed controller design procedure and their performance for the IPMSM based next generation high speed railway traction system. The next generation high speed railway system is a power distributed type and uses vector control method for a motor speed control. Since the speed and current controller gains of the vector control system directly affects to the transient characteristics and speed control capability, the systematic design of the controllers are required. In this paper the controllers are designed using the IPMSM based next generation high speed railway system parameters. Simulation programs based on Matlab/Simulink is developed. Finally the controller characteristics are analyzed by the simulation results.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.371-380
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• 2005

The purpose of this experimental study was to evaluate aㅜd compare maxillary arch dimensional and positional changes between first and second premolar extraction groups. The Calorific Machine was used to illustrate tooth movement in three dimensions. The experimental teeth except the first or second premolars were embedded in artifical alveolar bone. The extraction space was closed using arch wires with bull loops into which 15 degree gable bends were placed. Before and after space closure, radiographs were taken in the sagittal and occlusal directions using occlusal films. The results showed greater mean maxillary incisor retraction and less anchorage loss in the maxillary first premolar extraction group than in the maxillary second premolar extraction group. Mesiopalatal rotation of anchor teeth was greater after extraction of a maxillary second premolar than a maxillary first premolar (P<.001).

• Journal of Digital Convergence
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• v.20 no.5
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• pp.211-220
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• 2022

This paper proposes a green closed-loop supply chain network (GCSN) for optimizing closed-loop supply chains. The GCSN focuses on the application of the recycling express box in logistics circulation, accelerates the standardization of logistics operations and the use of express packaging in e-commerce companies, and promotes the reduction and greening of recycling express box in the e-commerce industry. The GCSN is represented as a mathematical formulation and implemented using LINGO. Greening, environmental protection, and wisdom are the general trends for promoting the growth of the e-commerce industry. Meanwhile, the price of raw materials has increased owing to a shortage of resources, which emphasizes the need for e-commerce enterprises to develop green packaging. Therefore, this study considers the shared circular packaging launched by e-commerce enterprises as the research object, and integrates the problem of facility positioning and path planning in the logistics system. The conclusion summarizes the significance of this study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1092-1099
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• 2006

Displayed system equationally using accurate dynamic modeling of whole system including induction motor and load to analyze induction motor to normal condiction's action characteristic as well as transient characteristic using power converter device such as inverter in this paper. Also, presume adhesive power calculation through speed sensorless vector control and load torque disturbance observer for maximum tractive force control. Confirmed proposed algorithm through simulation and an experiment using railroad experiment equipment to embody control algorithm of such system. With relation of adhesive power about the wage speed by speed addition and subtraction of railway vehicle, embodied all sorts item by experiment equipment.

• 재활복지
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• v.20 no.3
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• pp.141-161
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• 2016

This research is to anticipate problems of Ray's disabled experiment welfare vehicles for 17 drivers with disability, improving them. In addition it is to provide the criteria for ergonomic design based on perspective of drivers with disability by investigating 18 items of usability test. The results are as follows. First, satisfaction degree of Ray, disabled experiment welfare vehicle, was shown to be 3.88 which is higher than normal vehicles whose degree is 3.20. This showed that the disabled experiment welfare vehicle is the one with much improvement. Second, so as to develop a welfare vehicle it needs to take into account some factors including rear slope, wheelchair locker, seat belt, safety grip, and high roof. Third, in case of rear slope, high roof and width of manual or automatic wheel chairs should be considered and motor-operated device should also be taken into account for safety lockers, which make a wheelchair firmly fixed. Moreover, motor-operated seat and rear slope can be chosen for either of the disabled and the elderly.

• The korean journal of orthodontics
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• v.25 no.2 s.49
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• pp.143-152
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• 1995

This study was performed, by Finite Element Method, to evaluate the stress distribution on the periodontal tissue according to activation of the various closing loops and to predict the pattern of movement of maxillary incisors. At the same time, bull loop, key-hole loop, T-loop, combination loop and asymmetrical T-loop which were used for retraction of maxillary incisors was analysed by Finite Element Method. The following results were obtained 1. Horizontal force was the greatest in bull loop, the followed by key-hole loop, combination loop, T-loop and initial tooth movement exhibited uncontrolled tipping. 2. Horizontal force in asymmetrical T-loop compared to other closing loops was remarkably decreased, and the intrusive force on the incisors occurred. 3. As torque was increased, the moment was increased as a linear increment. 4. As moment was increased, initial movement of tooth changed to root movement from uncontrolled tipping.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1373-1379
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• 2012

The interaction of magnetic field in the frequency range of 9~150 kHz radiating from a railway system with wireless systems has been the cause of radio frequency interference. In this paper, the equivalent circuit model of the RFI noise is proposed through source and transfer path analysis, and it is confirmed that the switching noise of several kHz that occurs a vehicle traction drive system and a substation is radiated by forming the loop circuit with a feeder line by a rolling stock. And the validity of the proposed equivalent circuit model is verified by analyzing the effects of RC banks installed in the real railway between Guri and Guksu stations, the RFI noise can be effectively mitigated by loading suitable capacitance between rail and feeding line.

• The korean journal of orthodontics
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• v.32 no.1 s.90
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• pp.9-18
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• 2002

The present study hypothesized that the double keyhole looped archwire plays a positive role for the sake of translatory movement and/or controlled tipping of upper 6 anteriors, and secures anchorage control as well. The purposes of the study were to evaluate the changes in lateral cephalograms during orthodontic treatment with DKHLs and to compare the skeletal & dental changes before- & after-treatment. The materials of this study were lateral cephalograms of 20 adult patients with upper dentoalveolar protrusion both in class I and in class II Division1 malocclusion. Lateral cephalograms were taken before and after orthodontic treatment with upper 1st bicuspid extraction and DKHLs. The results were obtained as follows : 1. There were no statistically significant differences in skeletal measurement except SNB and PTFH between before- & after-treatment. The major changes were in dentoalveolar region. 2. After treatment, there were statistically significant decrease in dental measurement except interincisal angle. 3. Both upper & lower lip protrusion was decreased. 4. There were statistically differences in upper anterior crown horizontal & root vertical dimension(7.08 ${\pm}$ 2.14 mm, 2.38 ${\pm}$ 1.15 mm, p<0.01). 5. There were statistically differences in upper posterior dental(both crown & root) horizontal dimension(2.48 ${\pm}$ 0.99 mm, 2.05 ${\pm}$ 0.91 mm, p<0.01).