• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.36-41
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• 1988

Analog and Digital Speed Control Systems have mutually complementary properties. Analog System has good dynamic characteristics and moderate steady-state accuracy and can be implemented economically with operational a ampliers. Digital System, on the contray, has good static accuracy, but relatively poor dynamic property. So, a hybrid system which uses both digital and analog control can have good static and dynamic characteristics. In this paper, it is shown that a simple digital controller can improve steady-state accuracy of existing analog control system satisfactorily, and some design criteria are presented also.

• Journal of Ship and Ocean Technology
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• 제8권4호
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• pp.45-55
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• 2004

How to achieve engineering collaboration among diverse engineering activities is one of the key topics in manufacturing fields nowadays. The infrastructure for collaborative engineering is essential, and it can be realized by information technologies and intelligent engineering applications in digital environments. Digital Manufacturing is a technology to facilitate effective product developments and agile productions by computer models representing the physical and logical schema and the behavior of real manufacturing systems including products, processes and factories. A digital factory as a well-designed and integrated digital environment is incorporated in it. In this paper, digital manufacturing is recommended as a good strategy for collaborative engineering, especially in product developments and productions. By business process analysis and some case studies, we suggested sophisticated digital models are very useful to concurrent and collaborative engineering. It is expected that digital manufacturing is a very good strategy for achieving dramatic time and cost savings in many engineering activities of many manufacturing industries, including machinery, automotive and shipbuilding.

• 디지털융복합연구
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• 제12권5호
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• pp.459-466
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• 2014

부모도 가정에서, 자녀에게 리더이기 때문에 부모의 리더십을 갖추어야 한다. 좋은 부모는 저절로 태어나는 것이 아니라 만들어 지는 것이기 때문에, 본 연구는 좋은 부모가 되기 위해서는 먼저 좋은 리더가 되어야 하고, 더 큰 부모의 역량이 무엇인지, 꼭 필요한 좋은 부모 리더십의 원칙들이 무엇인지를 알아보고자 한다.

• 한국정밀공학회지
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• 제13권8호
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• pp.112-119
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• 1996

Among the various type of accelerometer, the servo rebalancing type accelermoter can be suitable for Inertial Navigation System, because of its high sensitivity and good response in low frequency. In this paper, we proposed a new technology to control inductive tuype accelerometer utilizing digital PWM method. The new developed digital PWM control has special design scheme for transmitting measurement value to outer device in its servo ollp. So it has no quantized error of transforming outputs of sensors to digital domain. The quantized error may make serious problem in INS system, because outputs of sensor are integrated once or twice by digital computer and it happens every sensor reading times. Therefore, in order to get the accurate information such as displacement, it is necessary to measure accurately the input current. In addition, Digital Signal Processing needs digital data transmission, digital PWM method is adaptive for this purpose. We realized a practical circuit for digital PWM control, analyzed the stability of the circuit, and designed the controller etc. In this study, we solved many practical problem for this application, and got out good results.

• 디지털융복합연구
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• 제6권2호
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• pp.41-53
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• 2008

This research is to redefine the concept of Good School and to validate an effective Good Secondary School Scale in Kyung-gi Province and Seoul. As statistical methods, SPSS 13.0 and AMOS 5.0 were used. Item Analysis and Exploratory Factor Analysis(EFA) were conducted to test the reliability of items and the factor structure. And Confirmatory Factor Analysis(CFA) was conducted to test the validity and fitness of the Good School Scale. The outcomes are as follows: First, six factors(school environment, curriculum, teacher, school-based management system, director) will increase the good schooling effectiveness. Second, As a result of Confirmatory Factor Analysis(CFA), the goodness of fit indices(GFI AGFI, CFI, RMSEA) demonstrate statistically significance and fitness of the model. The final Good School Scale supports 6 Good School Factors obtained in main test. Therefore, we can say that this scale can be used as a valid instrument to measure a real Good Schooling Effectiveness at the secondary school situation in Korea.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 전문대학교육위원 P
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• pp.56-60
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• 1999

This paper presents the high performance real time control system of PWM inverter for uninterruptible power supply(UPS). This system is based on a digital control scheme which calculates the pulse widths of the inverter switches for the next sampling time in digital signal processor(DSP). A PI compensator is used to eliminate the voltage error caused by the difference between the actual values of LC filter and those designed. Double regulation loops which are the inner current loop and the outer voltage loop are used to make the transient response time reduce in load disturbance and nonlinear load. This method makes it possible to obtain better response in comparison to conventional digital control system. The proposed scheme provides good performance such as stable operation, low THD of the output voltage, and good dynamic response for load variations and nonlinear load.

• 한국컴퓨터정보학회논문지
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• 제24권7호
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• pp.71-78
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• 2019

This paper describes a design for a RF receiver to receive satellite digital audio service. The RF receiver designed in this study is a planar structure that is easy to install on the rooftop of a car and is compact in size. In addition, it can be applied to certain commercial models because it has low noise and high gain characteristics. The impedance bandwidth of antenna is 17.8%(415MHz), and the axial ratio is below 3dB as good properties for the bandwidth of 40MHz which is a satellite digital audio service band. Also, it had a broad radiation beamwidth of $95.41^{\circ}$ in H-plane and $117.45^{\circ}$ in E-plane. From the results of the field test of satellite digital audio service reception for the RF receiver, it demonstrated good C/N rate(10.2dB).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.724-727
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• 1993

This paper is presented real-time digital control techniques of the PWM inverter for UPS. This proposed system is based on instantaneous digital control scheme which is empolyed double dead beat control and prediction method. Especially, to supply the load current from the inverter without the computation delay, the predictive methods are used to generate the load current signal. From the simulation and experimental results, it is shown that presented scheme has good performance such as very low THD of the output voltage, and good dynamic response under the nonlinear load. The experimental implementation of the system is estabilished by using the TMS320C25 DSP.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2002년도 방송기술 국제워크샵
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• pp.3-16
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• 2002

.Service Industry good digital contents are few high cost of broadcasting right Satellite broadcasting will be dominant in many countries Interactive TV service will be an engine of digital broadcasting .DTVsets Industry Big Market is coming

• 한국정보기술학회 영문논문지
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• 제8권2호
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• pp.41-46
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• 2018

As evidenced through rapidly growing digital devices and information, digital authentication is becoming ever more critical, especially considering the complex and prevalent digital accounts we are using every day. Also, digital authentication is apt to consistent digital security application. In this sense, digital security quality and usability can be enhanced by developing a mechanism for efficient digital authentication. In this paper, a mechanism of efficient digital authentication called T-TIME is introduced in order to alleviate issues dealing with secure and user friendly authentication across ever- growing digital devices and information. Touch Signal generation time difference is utilized for T-TIME as a mediation mechanism that enhances the security quality by confusing others unlike other graphical password mechanisms which are using spatial information. Hence, digital authentication by using T-TIME can be a good way of enhancing security quality and usability.