• 전자공학회논문지B
• /
• 제33B권7호
• /
• pp.86-98
• /
• 1996

Modulation and demodualtion circuits of chaos frequency shift keying have been implemented using chua's circuits. The modulatin circuit, which is designed ot perform the frequency-doubling by coupled synchronization wihtout changing the intrinsic characteristics of its two chaos signals generated, modulates the digital input signals. The demodulation circuit detects the digital input signals form carrier by drive synchronization. these circuits, which are simplest until now and have no restriction to their digital input amplitudes, perform the aimed functions.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2007년도 하계학술대회 논문집
• /
• pp.19-21
• /
• 2007

This paper proposes an input waveform improvement using VIENNA Rectifier(three-phase/level/switch). VIENNA Rectifier is based on the combination of a three-phase diode bridge and dc/dc converter. It features low input current ripple and sinusoidal mains current form.

• ETRI Journal
• /
• 제29권1호
• /
• pp.89-94
• /
• 2007

A mathematical model for the input-output characteristic of an amplifier exhibiting gain expansion and weak and strong nonlinearities is presented. The model, basically a Fourier-series function, can yield closed-form series expressions for the amplitudes of the output components resulting from multisinusoidal input signals to the amplifier. The special case of an equal-amplitude two-tone input signal is considered in detail. The results show that unless the input signal can drive the amplifier into its nonlinear region, no gain expansion or minimum intermodulation performance can be achieved. For sufficiently large input amplitudes that can drive the amplifier into its nonlinear region, gain expansion and minimum intermodulation performance can be achieved. The input amplitudes at which these phenomena are observed are strongly dependent on the amplifier characteristics.

• 전자공학회논문지T
• /
• 제35T권3호
• /
• pp.53-60
• /
• 1998

본 논문에서는 키보드를 사용하지 않는 PDA 등 휴대형 컴퓨터에서 입력의 수단으로 사용하는 온-라인 문자 인식기를 위한 문자 필기글꼴을 제안하였다. 제안된 필기글꼴은 키보드를 통하여 입력 가능한 수준의 한글 자소와 영숫자이며, 필기글꼴의 정의를 위하여 한글의 풀어쓰기 글꼴과 영문자의 PDA용 필기 패턴인 그래피티 문자를 분석하여, 한글과 영숫자 입력 모드 전환이나 필기 영역의 구분 없이 연속 필기하여도 인식 가능하도록 중복되는 글꼴을 갖지 않도록 하면서 최대한 원형을 유지하도록 하였다. 본 논문에서 제안한 필기글꼴의 타당성을 고찰하기 위하여 그래피티 문자를 알고 있는 PDA 사용자 그룹과 일반인들을 대상으로 인지도와 만족도를 조사하였다. 두 피실험 그룹의 영숫자 및 한글의 자음의 인지도 및 만족도는 98% 이상이었고 한글 모음의 경우 95% 이상의 긍정적인 반응을 얻었다.

• 한국의학물리학회지:의학물리
• /
• 제29권1호
• /
• pp.23-28
• /
• 2018

The purpose of this study is to build a database of patient information for efficient radiotherapy management. Microsoft Office Access was used to build the database owing to its convenience and compatibility. The most important aspect when building the patient database is to make the input and management of patient information efficient at every step of radiotherapy process. The information input starts from the patient's first visit to the radiation therapy department and ends upon completion of the radiotherapy. The forms for each step of radiotherapy process include the patient information form, the radiotherapy schedule form, the radiotherapy information form, the simulation order form, and the patient history form. Every form is centrically connected to the radiation oncology department's patient information form. A test revealed that the database was found to be efficient in managing patient information at each step. An important benefit of this database is improved efficiency in radiotherapy management. Information on patients who received radiotherapy is stored in a database. This means that this clinical data can be found easily and used in future, which will be helpful in research studies on the radiation oncology department. Benefits such as these will potentially contribute to improved radiotherapy quality.

• 디지털융복합연구
• /
• 제13권11호
• /
• pp.337-348
• /
• 2015

터치 인터페이스 입력방식에서 메뉴를 마우스를 이용하여 입력하는 것 보다 터치입력 방식이 의도하지 않는 터치와 입력의 어려움이 증가하고 있다. 본 연구에서는 버튼메뉴의 최소 형상버튼을 기준으로 형태와 크기변화에 따라서 사용성 평가를 분석하고자 한다. 적용방법으로는 터치 입력방식의 인터페이스 디자인에서 활용 할 수 있도록 회귀 모형식과 인터페이스 인간 수행 평가방법의 대표적인 모형인 피츠의 법칙(Fitts' Law)의 비교분석을 통해서 더욱 효과적인 정량적 수행예측 평가 모형식 적용을 통해서 가능성을 확인하고자 했다. 따라서 터치 환경에서 적용할 수 있는 버튼의 형상과 크기변화에 따른 사용자의 사용시간을 고려한 수행예측시간을 디자인에 반영할 수 있다.

• 대한전기학회논문지
• /
• 제41권8호
• /
• pp.902-913
• /
• 1992

There have been several control schemes for the single input systems with unmeasurable state variables using variable structure control(VSC) theory. In the previous VSC, the systems must be represented in phase canonical form and the complete measurements for each state variable must be assumed. In order to eliminate these restrictions several VSC methods were proposed. And especially for the systems in phase canonical form with unmeasurable state variables, the reduced order switching function algorithm was proposed. But this method has many drawbacks and can not be used in the case of general form (not phase canonical form) dynamic system. Therefore this paper propose new construction method of switching fuction for the systems in phase canonical form, which reduce the restriction of reduced order switching function algorithm. And this algorithm can be realized for any state representation and adopted in the systems where not all states are available for switching function synthesis or control.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2008년도 하계학술대회 논문집
• /
• pp.34-36
• /
• 2008

This paper is given a full detail of mathematical analyses of input current for novel active type power factor correction(PFC) AC-DC converter of step up-down added electric isolation. These are compared with harmonics components of input current for a conventional PFC converter of electric isolation type. The proposed PFC converter is constructed in using a new loss-less snubber circuit to achieve a soft switching of control device. Also the proposed converter for discontinuous conduction mode(DCM) eliminates the complicated circuit control requirement and reduces the size of components. The input current waveform in the proposed converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, input power factor is nearly unity and the control method is simple. Particularly, the stored energy of loss-less snubber capacitor is recovered with input side and increases input current from resonant operation. The result is that input power factor of the proposed converter is higher than that of a conventional PFC converter. Some simulative results on computer and experimental results are included to confirm the validity of the analytical results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제54권12호
• /
• pp.622-628
• /
• 2005

This paper is given a full detail of mathematical analyses of input current and output voltage for a novel active type power factor correction (PFC) converter. These are compared with harmonics components of input current for a conventional PFC converter. The proposed PFC converter is constructed in using a new loss-less snubber circuit to achieve a soft switching of control device. Also the proposed converter for discontinuous conduction mode (DCM) eliminates the complicated circuit control requirement and reduces the size of components. The input current waveform in the proposed converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of ac input voltage under the constant duty cycle switching. Therefore, input power factor is nearly unity and the control method is simple. Particularly, the stored energy of loss-less snubber capacitor is recovered with input side and increases input current from resonant operation. The result is that input power factor of the proposed converter is higher than that of conventional PFC converter. Some simulative results on computer and experimental results are included to confirm the validity of the analytical results.

• 제어로봇시스템학회논문지
• /
• 제17권11호
• /
• pp.1138-1144
• /
• 2011

This article deals with the problem of fault detection of a spacecraft's actuators. The authors introduce an extended unknown input observer for nonlinear systems. This is an extended form of unknown input observers which are used for linear systems. Since faults are not available, those are considered as unknown inputs. Unknown input observers can estimate states without full information of inputs if some conditions are satisfied. The authors suggest a continuous-time extended UIO (eUIO) and prove the convergence of state estimation errors. Since the dynamic equation of a spacecraft is nonlinear, an extended UIO can be applied. Three eUIOs are designed to monitor three reaction wheels. The moving averages of each eUIO's residuals are selected for decision logic. The proposed method is verified by numerical simulations.