• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.127-142
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• 2000

This study have been carried out to find out the mechnical effect of Multiloop Edgewise Arch Wire(MEAW) making use of the finite element method. The tip back bend of MEAW taken in this analysis is $5^{\circ},\;10{\circ}\;and\;15{\circ}$. In addition, Class II or up & down elastic is applied to find out stress distribution and their values in PDL. A adult male of normal occlusion was selected to create the models of teeth and PDL. And the model of MEAW was also created using commercial finite element code (ANSYS version 5.2). The MEAW is forcibly engaged with a class II or up & down elastic, to determine the initial stress generated in PDL. Comparing the compressive and tensile stress at each reference-planes, following results are obtained. 1. When a MEAW of $5^{\circ},\;10{\circ}\;15{\circ}$ tip back bend was engaged with Class II or up & down elastic, the distribution of compressive, tensile stress in entire PDL is similar in each case. 2. The values of compressive and tensile stress in PDL is higher in $15{\circ}$ tip back bend case than in $10{\circ}\;or\;15{\circ}$ tip back bend case. 3. In the distal PDL of 1st and 2nd molar, compressive stress appears. The compressive area is more wide and its values is higher in PDL of 2nd molar than those in 1st molar. The compressive area and its values become more wide and higher according to the increase of the tip back bend. 4. The values of compressive stress are comparatively smaIIer in PDL of molars than those in premolars. 5. Comparing class II and up & down elastic case, tensile stress values in anterior teeth PDL are smaller md their distribution is more wide in up & down elastic case than class If elastic case. On another hand, there is no difference in distribution and stress values in PDL of posterior teeth between two cases. 6. Comparing the tensile area in PDL of anterior teeth, tensile stress values are maximum in PDL of canine.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.229-234
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• 2005

A novel method to measure the interaction movement, focusing direction and tracking direction in an optical pick-up, is proposed and the decoupling control for it is discussed. First, the basic principle of the coupline analysis method using back electromotive farce is introduced. Second, the interaction analysis between focusing direction and tracking direction fur commercial slim type actuator is performed using the proposed method. Finally, the coupling analysis and decoupling control for the slim type optical pick-up are discussed. From the brief simulation, we shows that the effectiveness and validity of the proposed method.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2661-2663
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• 2005

To construct the stable back-up system between mini-hubs, we propose the plan of site diversity of asynchronous mini-hub by monitoring outlink carriers and error data. In this paper, we made hardware and software to control mini-hub system for site diversity back-up by switching SDBS equipment through communication between master mini-hub and slave mini-hub.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.603-606
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• 1987

A simulator is designed in order to evaluate the performance a f a lockup controller. The original analog controller and boiler plant are transformed into digital form model, in which the plant is modeled as a 2 input-2 output system connected to first order peripheral units. The experimented results show that the simulated system renders the same steady state characteristics as data and show usability of simulator.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.38-38
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• 2000

To fulfill recent requirements for high quality products in steel rolling process, fast responding and easily tunab control system is required and ILQ(Inverse Linear Quadratic) control system may be one of such alternatives. In this paper characteristics of ILQ control and its application to BUR(Back-Up-Roll) eccentricity in strip rolling mill is discussed and compared to polynomial control approaches. Also the rolling mill model and basic principle to control thickness of srip are introduced with control effect by polynomial methods.

• 한국기계연구소 소보
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• s.16
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• pp.3-16
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• 1986

The first specimens were sampled across the depth of roll products processed by rapid heating and cooling of the roll, namely, differential heat treatment. The second samples were taken from the non-heat treated roll at different depths. The samples were heat treated following the same temperature history as that at each corresponding location in the roll where the samples were taken. Consequently, both specimens showed the similar microstructure and mechanical properties (tensile, impact and fatigue strength etc.)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.729-734
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• 2017

A safety relief valve is a device that relieves excessive pressure in piping lines or tanks and maintains pressure at the appropriate pressure level for use. The (pressure in the) safety valve is directly influenced by the change in the back pressure, depending on whether the vents in the spring bonnet are vented to the atmosphere or to the outlet. The back pressure is divided into the built-up back pressure and the superimposed back pressure, and the back pressure characteristics vary according to the usage conditions. The safety valve used in this study is a Conventional Safety Relief Valve. The blowdown of the safety valve is predicted by establishing the equilibrium equation between the opening force and spring force considering the back pressure characteristics. Its reliability is secured by using CFX17.1. In addition, the safety of the safety valve trim was examined through fluid-structure interaction analysis.

• International Area Studies Review
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• v.20 no.2
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• pp.85-111
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• 2016

Global semiconductor companies is investing enormous capital worldwide. And direct investment in China is increasing greatly these days, Especially, global semiconductor companies are setting up a factory in China due to expanding market rather than utilizing low labor cost. Therefore, this study is trying to analyze the background and process of direct investment from global Korean and Taiwanese semiconductor companies in China. Firstly, In 1996, Samsung semiconductor established a back end process factory in Suzhou. And in 2014, Samsung semiconductor set up a front and back end factory in Xian. Secondly, In 2006, SK Hynix built a front and back end factory in Wuxi. and SK Hynix set up a back end factory named Hitech semiconductor with Chinese company in 2009. Later in 2015, SK Hynix established a back end factory in Chongqing. Thirdly, In 2004, TSMC started to operate a factory in Shanghai, and in 2018, TSMC is going to establish a factory in Nanjing. Lastly, UMC bought a stock to produce product in Chinese local company named HJT, and at the end of 2016, UMC is going to finish building a factory in Xiamen. As a result, it was proved that most companies hoped to expand the chinese market by setting up a factory in china. In addition, Samsung expected to avoid a risk by setting up a factory in china, and SK Hynix wanted to avoid a countervailing duty by setting up a factory in china. Based on the result of this study, this study indicates some implications for other semiconductor companies which are very helpful for their future foreign direct investment.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.253-263
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• 2011

Objectives : To analyze the therapeutic outcomes of back pain modalities in patients with disc herniation according to the change of magnetic imaging(MRI) at one year after conservative treatment. Methods : Clinical outcomes of 35 patients diagnosed with lumbar disc herniation by MRI examination, treated conservatively, were analyzed according to MRI follow-up change; improved, unchanged, worsened. Patients underwent MRI examination at baseline and after 24 week of treatment. After 1 year, we followed up 30 patients. The patients' clinical outcomes were assessed at baseline, 24 week, 1 year by visual analogue scale(VAS), oswestry disability index (ODI), and analyzed by each of it's correlation. Results : 1. VAS of sciatica and ODI of disability of daily activities showed significant decrease in patients after 1 year follow up(p<0.05). 2. VAS(low back pain and sciatica) and ODI of disability of daily activities showed significant decrease in "improved" group and VAS(sciatica) and ODI showed significant decrease in "unchanged" group. "worsened" group showed no statistic significance(p<0.05). 3. The 1 year follow-up of VAS(low back pain and sciatica) and ODI change showed relationship with MRI follow-up change(p<0.05). Conclusions : This study suggests that "improved" groups compared to "unchanged" and "worsened" group on MRI follow-up in patients with lumbar disc herniation were more effective at 1 year after conservative treatment. MRI follow-up change affect clinical changes in patients with lumbar disc herniation after 1 year.

• Journal of the Korean Society for Railway
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• v.12 no.3
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• pp.437-442
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• 2009

In the case of a Linear Induction Motor (LIM), numerical analysis method like Finite Element Method (FEM) has been mainly used to analyze the travelling magnetic field problem which includes the velocity-induced electromotive force. If the problem including the velocity-induced electromotive force is analyzed by FEM using the Galerkin method, the solution can be oscillated according to the Peclet Number, which is determined by conductivity, permeability, moving velocity and size of mesh. Consequently, the accuracy of the solution can be low and the vortexes of flux can be occurred at the secondary back-iron. These vortexes of the flux occurred at the secondary back-iron does not exist physically, but it can be occurred in the analysis. In this case, the vortexes of the flux can be generally removed by using Up-Wind method which is impossible to apply a conventional S/W tool (Maxwell 2D). Therefore, in this paper, authors examined the vortexes of the flux occurred at the secondary back-iron of the LIM according to variations of the Peclet Number, and analyzed whether these vortexes of the flux affect on the dynamic force characteristics of the LIM or not.