• Journal of Korea Trade
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• v.24 no.1
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• pp.82-98
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• 2020

Purpose - This study aims to overcome the limitations of existing studies, which linearly determine the precedence factors of competency in overseas subsidiaries. The research objectives are as follows. First, what kind of nonlinear effects does the level of control held by Korean headquarters over foreign subsidiaries have in terms of competency in the subsidiaries? Second, what kind of nonlinear effects do the local experiences of overseas subsidiaries have on their competency? Design/methodology - With data on Korean multinational corporations (MNCs), this paper analyzes the effects of control levels of headquarters (HQs) and host-country experiences of foreign subsidiaries regarding competency in overseas subsidiaries. In particular, this study focuses on nonlinear models, differentiating it from previous studies. In order to examine research hypotheses, this study conducted a survey of overseas subsidiaries of Korean corporations. Surveys were conducted through various methods including e-mail, online questionnaires, fax, and telephone calls. Copies of the questionnaire were distributed to a total of 2,246 overseas subsidiaries, and 409 completed responses were collected. Excluding 15 copies that were insufficiently answered, responses from a total of 394 copies were used for analysis. Findings - This study presents the following results. First, there is a U-shaped relationship between levels of HQ control and competency in foreign subsidiaries. This means that higher levels of HQ control negatively impact the competency levels of subsidiaries because strict control undermines autonomy in subsidiaries. However, if the level of HQ control exceeds a certain point, then the transfer of knowledge between HQs and subsidiaries is facilitated. Knowledge transferred from HQs can be used as prior knowledge by foreign subsidiaries to the benefit of all parties. Accordingly, knowledge transfer negates the negative effects of excessive HQ control and positively affects competency in subsidiaries. Second, there is an inverted U-shaped relationship between the local (host-country) experiences of subsidiaries and competency in foreign subsidiaries. This means that foreign subsidiaries can overcome the liabilities of foreignness and contribute to capability building by accumulating unique knowledge about their host countries. However, if local experiences accumulate excessively beyond a certain point, then the host country-specific experiences of foreign subsidiaries will offset the benefits discussed above. Excessive local experiences not only increase organizational inertia, but also create a problem of goal incongruence due to information asymmetry between HQs and subsidiaries. Therefore, excessive local experiences have negative effects on competency in foreign subsidiaries. Originality/value - This study suggests the following implications. First, unlike existing studies based mainly on linear models, this study presents important theoretical implications in its focus on nonlinear models and its analysis of the effects of HQ control and local experiences on competency in foreign subsidiaries from perspectives of organizational learning theory and agency theory. Second, in terms of practical implications, the results of this study suggest that optimally raising levels of HQ control and managing the local experiences of subsidiaries without increasing organizational inertia is important for enhancing competency in foreign subsidiaries.

• Toxicological Research
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• v.22 no.4
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• pp.417-422
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• 2006

Cytogenetic and hematological analysis was performed in peripheral blood obtained from cattle bred in the high background radiation areas (HBRA, Goesan-gun, Cheongwon-gun, Boeun-gun) and a control area. The frequencies of gamma-ray induced micronuclei (MN) in the cytokinesis-blocked (CB) lymphocytes at several doses were measured in 3 cattle. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the bovine lymphocytes exposed in vitro to radiation over the range from 0 mGy to 1,969 mGy. The measurements performed after irradiation showed dose-related increases in the MN frequency in each donors. The results were analyzed using a linear-quadratic model with a line of best fit of $y=(0.0583{\pm}0.0137)D+(0.0366{\pm}0.0081)D^2+(0.0093{\pm}0.0015)$ (y=number of MN/CB cells and D=irradiation dose in Gy). MN rates per 1,000 CB lymphocytes of cattle from the Goesan-gun, Cheongwon-gun, Boeun-gun and the control area were $6.50{\pm}2.72,\;9.00{\pm}4.50,\;10.89{\pm}4.23\;and\;9.60{\pm}4.70$, respectively. The MN frequencies of CB lymphocytes from cattle bred in 4 areas mean that the values are within the background variation in this experiment. The MN frequencies and hematological values were similar regardless of whether the cattle were bred in the HBRA or the control area.

• Korean Journal of Veterinary Research
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• v.45 no.4
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• pp.469-475
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• 2005

Cytogenetic and hematological analysis was performed in peripheral blood obtained from pigs bred in the high background radiation areas (HBRA) (Cheongwon-gun and Boeun-gun) and a control area. The frequencies of gamma-ray induced micronuclei (MN) in the cytokinesis-blocked (CB) lymphocytes at several doses were measured in three pigs. An estimated dose of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the swine lymphocytes exposed in vitro to radiation over the range from 0 mGy to 1,969 mGy. The measurements performed after irradiation showed dose-related increases in the MN frequency in each donors. The results were analyzed using a linear-quadratic model with a line of best fit of $y=0.0005404D^2+0.04237D+0.00833$ [y = number of MN/cytokinesis-blocked (CB) cells and D = irradiation dose in Gy]. MN rates per 1,000 CB lymphocytes of pig from the HBRA (Cheongwon-gun, Boeun-gun) and the control area were $6.70{\pm}2.36$, $9.00{\pm}3.50$ and $11.00{\pm}2.98$, respectively. The MN frequencies of CB lymphocytes from pigs bred in three areas means that the values are within the background variation in this experiment. The MN frequencies and hematological values were similar regardless of whether the pigs were bred in the HBRA or the control area.

• Journal of Korea Planning Association
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• v.54 no.3
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• pp.15-26
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• 2019

The development of science and transportation technology leads to the increase of inter - city networks that play an important role in urban growth. Overall, numerous studies based on network theory pay attention to positive effects of urban network on urban growth. However, some studies have pointed out the negative effects of inter-city interactions such as straw effects. This implies that the network between cities may not be positively correlated with urban growth, and that the direction of the influence may vary from a certain threshold, such as the marginal utility curve. In this context, the purpose of this study is to measure the impacts of network with central city on urban growth in the capital region and examine the relationship between urban network and growth. Two multiple regression models are employed with changes in population and employment as dependent variables. The urban network index and other control variables are used as independent variables. Especially, the urban network indexes are used in quadratic forms to examine non linear relations with urban growth such U-shape or an inverted U-shape. The results show that the relationships between networks with the central city and urban growth are not a simple linear, and the influence can be changed from the critical point.

• Journal of Power Electronics
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• v.12 no.1
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• pp.145-156
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• 2012

These days, the application of electronic power transformers (EPTs) is expanding in place of ordinary power transformers. These transformers can transmit power via three or four wire converters. Their dynamic performance is extremely important, due to their complex structure. In this paper, a new method is proposed for improving the dynamic performance of distribution electronic power transformers (DEPT) by using sliding mode control (SMC). Hence, to express the dynamic characteristics of a system, different factors such as the voltage unbalance, voltage sag, voltage harmonics and voltage flicker in the system primary side are considered. The four controlling aims of the improvement in dynamic performance include: 1) maintaining the input currents so that they are in sinusoidal form and in phase with the input voltages so they have a unity power factor, 2) keeping the dc-link voltage within the reference amount, 3) keeping the output voltages at a fixed amount and 4) keeping the output voltages in sinusoidal and symmetrical forms. Simulation results indicate the potential and capability of the proposed method in improving DEPT behavior.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.324-327
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• 1996

This paper describes the robust controller design methods applied to the problem of an automatic system for tow-vehicle/trailer combinations. This study followed an inverse Linear Quadratic Regulator(LQR) approach which combines pole assignment methods with conventional LOR methods. It overcomes two concerns associated with these separate methods. It overcomes the robustness problems associated with pole placement methods and trial and error required in the application of the LQR problem. Moreover, a Kalman filter is used as the observer, but is modified by using the loop transfer recovery (LTR) technique with modified transmission zero assignment. The proposed inverse LQG,/LTR controllers enhances the forward motion stability and maneuverability of the combination vehicles. At high speeds, where the inherent yaw damping of the vehicle system decreases, the controller operates to maintain an adequate level of yaw damping. At backward moton, both 4WS (2WS tow-vehicle, 2WS trailer) and 6WS (4WS tow-vehicle, 2WS trailer) control laws are proposed by using inverse LQG/LTR method. To evaluate the stability and robustness of the proposed controllers, simulations for both forward and backward motion were conducted using a detailed nonlinear model. The proposed controllers are significantly more robust than the previous controllers and continues to operate effectively in spite of parameter perturbations that would cause previous controllers to enters limit cycles or to loose stability.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.3
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• pp.37-53
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• 2016

This paper deals with an optimal output control for Space Shuttle Main Engine (SSME), a liquid propellant rocket engine using a staged-combustion cycle. For this purpose, we modeled simplified mathematical model of SSME using each SSME component divided into 7 major categories and found trim points called Rated Propulsion Level (RPL). For design the closed-loop system of SSME, we designed optimal output feedback Linear Quadratic Regulation (LQR) control system using SSME linearized model under RPL 104% and demonstrated the performance of the controller through numerical simulation.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.333-338
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• 2003

Cytogenetic and hematological analysis was performed in bovine peripheral blood from the regions around Wolsong nuclear power plant and control area. The frequency of micronuclei (MN) in peripheral blood lymphocytes from cattle was used as a biomarker of radiobiological effects resulting from exposure to environmental radiation. An estimated dare of radiation was calculated by a best fitting linear-quadratic model based on the radiation-induced MN formation from the bovine lymphocytes exposed in vitro to radiation over the range from 0 Gy to 4 Gy. MN rates in lymphocytes of cattle from Wolsong nuclear power plant and control area were 9.87/1,000 and 9.60/1,000, respectively. There were no significant differences in MN frequencies and hematological values in cattle between Wolsong and control area. The study indicates that the MN assay is a rapid, sensitive and accurate method that can be used to monitor a large population exposed to radiation.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.6
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• pp.57-66
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• 1999

In this paper, we propose design methods of suspension controller for magnetically levitated system(MAGLEV). In this interior, the study of Electromagnetic Suspension(EMS) which has several advantages is chiefly achieved but, because the EMS has highly nonlinear and unstable property it is difficult to design the suspension controller maintaining stability and high performance. Here a Gain Scheduling Control(GSC) based on pole-placement scheme and on linear quadratic gaussian(LQG) design is separately presented. The several control performance is shown by simulation.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.433-436
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• 1990

An optimal Stabilization technique for a bilinear in duction model is introduced. This technique includes to o parts; the one is an stabilization control using Lyap unov Function which has the form of a sum of linear and quadratic function of the state variables, and the other is an optimal control using the performance index which depends on the choice of the elements of the Ly apunov matrices concerning both the state variables and the input variables. Therefore, induction motor is drived with the shorter transient time of the state variables and with the smaller overshoot of the ones, simulation results are obtained from a digital computer. Experimental ones are obtained from implementation of the optimizing controller using 8086 microprocessor kits and analog circuits are compared.