• Journal of Korea Trade
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• 제25권6호
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• pp.57-77
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• 2021

Purpose - International strategic alliance has been regarded as a strategic decision made by firms' managerial problems and ensure performance growth. From the perspective of the proactive behavior for changing strategies in a global market, this study aims to identify whether performance feedback influences firms' decisions to pursue strategic alliances. This study examines the effects of performance feedback on performance when firms use strategic alliances. Design/methodology - To analyze the impact of performance feedback on forming an international strategic alliance, this study adopt the concept of performance feedback to develop a research model and our hypotheses. Thus, this study used a two-stage least squares unbalanced panel data analysis with random effects. This study is based on 24,543 observations from Korean manufacturing firms from 2007 to 2016. Findings - The results show that firms pursue the formation of strategic alliances more actively, if their past financial and R&D performance are lower than their aspiration level, based on the result of performance feedback. An in split sample analysis for examining the effect of a firm's technology sophistication based on the OECD's classification, negative innovation performance discrepancy has positive effects on the probability of international alliance in high-tech and medium-high-tech industries. Financial performance also improves when a firm decides to form a strategic alliance based on the results of performance feedback. Originality/value - This research extends recent efforts to better understand the effect of performance feedback on firms' performance when they use strategic alliances. These findings suggest that the CEOs and managers of firms should consider the performance feedback perspective when deciding to pursue a strategic alliance to improve performance. In other words, the decision-makers in a firm must analyze and consider various complex variables inside and outside the firm and expand such subjects of examination to more complex and dynamic factors.

• 한국통신학회논문지
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• 제31권12A호
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• pp.1182-1188
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• 2006

적응 변조 OFDM(Orthogonal Frequency Division Multiplexing) 전송 기법은 각 부반송파의 채널 상태에 따라 변조방식을 적절히 변화시켜 무선 채널의 다중 경로 페이딩에 의해 의한 영향을 최소화하여 시스템의 성능을 증가시키는 방식이다. 시스템이 적응적으로 전송하기위해서는 단말기에서 각 부반송파(subcarrier)별 채널 상태 정보 (Channel State Information : CSI)를 되먹임 채널을 통해 실시간으로 기지국으로 전송해 주어야한다. 하지만, 단말기에서 데이터를 처리할 때 걸리는 시간과, 단말기에서 기지국으로 CSI를 되먹임(feedback) 할 때 걸리는 시간으로 인한 되먹임 지연(feedback delay) d가 발생하게 된다. 이 되먹임 지연은 CSI 정보의 불일치를 발생시켜 적응 OFDM 시스템의 성능저하를 일으킨다. 본 논문에서는 CSI의 되먹임 지연 $d(\geq2)$를 적절히 보상하는 주파수 축 멀티 스탭 채널 예측기를 제안하고 이를 적응 전송 OFDM 시스템에 적용하고 모의실험을 통하여 기존의 OFDM 시스템, 기존의 채널 예측방식과의 성능을 MSE(mean square error), 비트오율(bit error rate : BER) 및 채널용량을 바탕으로 비교한다.

• 수산해양교육연구
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• 제27권3호
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• pp.791-803
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• 2015

This study aims to examine the influence of tennis instructors' coaching behaviors on the satisfaction with lessons and preference for instructors. In order to achieve this study objective, by using the quota sampling out of nonprobability sampling for tennis club members who are now(2015) actively involved in tennis courts located in Daejeon Metropolitan City and Chungcheongnam-do, and also receiving tennis lesson for more than six months or used to take lessons before, the 325 effective samples were used for data analysis. Using the SPSS Ver. 21.0 Window Program, the collected data went through frequency analysis, exploratory factor analysis, reliability analysis, t-test, one-way ANOVA, correlation analysis and multiple regression analysis, and the results are like below. Regarding differences of coaching behaviors depending on sex, first, there were significant differences in the factors like explanatory instruction, positive feedback and negative feedback. In case of differences in accordance with age, every factor showed significant differences. In regard of differences depending on academic background, there were differences in the factor of negative feedback while the factor of positive feedback showed differences in accordance with the experience of lesson. In case of differences depending on the level of athletic performance, there were statistically significant differences in the factors like explanatory instruction, questioning instruction and negative feedback. Second, the positive feedback, one of the sub-factors of coaching behaviors had positive influence on satisfaction with lesson while the explanatory instruction, one of the sub-factors of coaching behaviors had positive influence on preference for instructors. Lastly, the satisfaction with lesson had positive influence on preference for instructors.

• 한국심리학회지 : 코칭
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• 제6권2호
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• pp.45-73
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• 2022

본 연구의 목적은 코칭리더십이 인사평가효과성에 미치는 영향과 코칭리더십이 인사평가효과성의 관계에서 부정피드백 추구행동의 매개효과와 코칭리더십이 부정피드백 추구행동에 영향을 미치는 데 있어서 심리적 안전감의 조절효과를 밝히는 데 있다. 이를 위해 국내 다양한 기업에서 종사하는 직장인 300명을 대상으로 온라인 설문조사를 통해 자료를 수집하였다. 본 연구의 결과는 다음과 같다. 첫째, 코칭리더십과 인사평가효과성의 관계에서 부정피드백 추구행동의 매개효과를 확인하였다. 둘째, 코칭리더십과 부정피드백 추구행동의 관계에서 심리적 안전감은 조절효과가 있는 것으로 검증되었다. 셋째, 조절된 매개효과는 유의미하지 않은 것으로 나타났다. 마지막으로, 본 연구에서는 연구결과를 토대로 학문적 의의와 시사점, 한계점 및 향후 미래 연구과제를 위한 제언을 논의하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.213-218
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• 2003

The equipment of industrial robot in manufacturing and assembly lines has rapidly increased. In order to achieve high productivity and flexibility, it becomes very important to develop the visual feedback control system with Off-Line Programming System(OLPS). We can save much efforts and time in adjusting robots to newly defined workcells by using OLPS. A proposed visual calibration scheme is based on position-based visual feedback. The calibration program firstly generates predicted images of objects in an assumed end-effector position. The process to generate predicted images consists of projection to screen-coordinates, visible range test and construction of simple silhouette figures. Then camera images acquired are compared with predicted ones for updating position and orientation data. Computation of error is very simple because the scheme is based on perspective projection which can be also expanded to experimental results. Computation time can be extremely reduced because the proposed method does not require the precise calculation of tree-dimensional object data and image Jacobian.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.864-869
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• 2004

A novel concept of feedback loop design for modal test and model updating is proposed. This method uses the closed -loop natural frequency information for parameter modification to overcome the problems associated with the conventional method employing the modal sensitivity matrix. To obtain new modal information from closed-loop system, controllers should be effective in changing modal data while guaranteeing the stability of closed-loop system. It is very hard to guarantee the stability of the closed-loop system with non-collocated sensor and actuator set. Ill this research, we proposed a controller called mode-decoupling controller that can change a target mode as much as the designer wants guaranteeing the stability of closed-loop system. This controller can be computed just using measured open-loop modeshape matrix. A simulation based on time domain input/output data is performed to check the feasibility of proposed control method.

• 유공압시스템학회논문집
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• 제1권3호
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• pp.14-19
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• 2004

The Direct Drive Valve used in this study contains a pressure-feedback-loop in itself, then it can eliminate nonlinearity such as the square-root-term in flow rate calculation and the change of bulk modulus of hydraulic oil. In this study, assuming that the dynamic characteristic of the DDV is modelled as a first order lag system, an parameter identification method using the input data and the output data is applied to obtain DDV's mathematical model. Then, a state feedback controller was designed to implement the force control of hydraulic system, and the control performance was evaluated.

• 한국소음진동공학회논문집
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• 제14권10호
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• pp.955-961
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• 2004

A novel concept of feedback loop design for modal test and model updating is proposed. This method uses the closed-loop natural frequency information for parameter modification to overcome the problems associated with the conventional method employing the modal sensitivity matrix. To obtain new modal information from closed-loop system, controllers should be effective in changing modal data while guaranteeing the stability of closed-loop system. But it is very hard to guarantee the stability of the closed-loop system with non-collocated sensor and actuator set. In this research, we proposed a controller called mode-decoupling controller that can change a target mode as much as the designer wants guaranteeing the stability of closed-loop system. This controller can be computed Just using measured open-loop modeshape matrix. A simulation based on time domain input/output data is performed to check the feasibility of proposed control method.

• 천문학회보
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• 제39권1호
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• pp.46.1-46.1
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• 2014

In understanding "cooling flow" problem and the galaxy-SMBH co-evolution, AGN feedback is considered as one of the most important phenomena. Among various AGN feedback phenomena, X-ray cavities are particularly useful for studying AGN feedback over 10 kpc scales, as the origin of X-ray cavities is believed to be related to radio jet from AGN. For a comprehensive study of X-ray cavities, we collect all available diffuse X-ray data of galaxies in various galaxy environments, ranging from field galaxies to galaxy clusters, using the Chandra X-ray data archive. As a result we build up a sample of 87 targets showing enough X-ray photons to perform the analysis. Using modeling and unsharp masking techniques, we detected X-ray cavities and measured their physical properties (i.e., cavity size) for the 49 targets. Here, we present X-ray cavity properties and discuss environmental effects.

• 전기학회논문지
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• 제64권4호
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• pp.586-591
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• 2015

This paper proposes a force feedback system of telepresence robot for remote operation. The ultrasonic sensors attached at the robot detect the obstacles, and generate the force to the operation joystick. In order to consider the network delay, we developed the fuzzy control system using ultrasonic data and robot speed. The method to calculate the force vector from the ultrasonic data is also presented to operate the robot more accurately. The simulation and experimental results are presented to verify the safe and accurate operation of the proposed system.