• 대한의생명과학회지
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• 제14권1호
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• pp.39-45
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• 2008

Inflammation is the complex biological response of injured tissues to harmful stimuli. A cascade of biochemical events propagates and matures the inflammatory response, involving the local vascular system, the immune system, and various cells within the injured tissue. The immune system is often involved with inflammatory disorders, demonstrated in both allergic reactions and some myopathies, with many immune system disorders resulting in abnormal inflammation. An Arbitrary Waveform Generator (AWG) is a piece of electronic test equipment used to generate electrical waveforms for the treatment of patients. The patients with gastritis and arthritis have been known to have a relatively favorable prognosis with AWG treatment. Accordingly, we examined the effects of AWG treatment in gastritis and arthritis animal model. The compound 48/80 was used to induce animal gastritis model. The tissue malone dialdehyde (MDA) and serum histamine levels, and the activity of superoxide dismutase (SOD) in stomach tissue were measured. The tissue MDA and serum histamine levels in AWG treated groups exhibited the decreased tendency compared with control group, whereas the tissue SOD activity was slightly increased. The Freund's complete adjuvant was used to induce animal arthritis model as well. The paw edema volume and the width of ankle joint were determined. The AWG treatment significantly decreased the paw edema volume after 5th day of treatment. Although further studies should be performed to confirm the effects of AWG treatment, present study suggest that AWG treatment might be used as a complementary treatment for the gastritis or arthritis treatment.

• 한국정밀공학회지
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• 제26권9호
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• pp.143-147
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• 2009

Inkjet printing makes use of ink droplets to form required patterns on a substrate. In order for the inkjet technology to produce reliable patterning tools, the jetting performance needs be controlled precisely. For controlling ink jetting performance, input waveform should be properly designed. In the past, the research was focused on designing dwell time of the input waveform for controlling jetting speed. However, the jetting performance is also closely related to rising and falling time. In this study, the effect of the rising and falling time on droplet speed will be investigated by measuring the droplet speed. In this study, the power OP amp (PA98A) was used in order to drive piezo inkjet head by amplifying the waveform generated from arbitrary function generator. The experimental results show that change of rising and falling time in the waveform not only affect the droplet speed but also optimal dwell time.

• 제어로봇시스템학회논문지
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• 제14권4호
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• pp.342-347
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• 2008

Bridge circuit was developed such that the pressure wave in the inkjet can be measured. In order to test the circuit, the microfab single ejector was used. For the experiment, the head was filled with nano silver ink (20wt%). In order to generate waveform voltage for jetting signal, the Agilent 33120 was used in order to generate arbitrary waveform. For the driver, PZD 350 from TREK was used in order to amplify the waveform. Experimental results show that the designed circuit can effectively detect the pressure wave in the inkjet head.

• 천문학회보
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• 제37권2호
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• pp.228.1-228.1
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• 2012

Digital waveform generation technology for SAR payload can be divided into DDS(Direct Digital Synthesizer) method and Memory Mapped(M/M) method. DDS is the single chip which consists of the Sine Table, NCO(Numerically Controlled Oscillator), DAC, and so on. DDS method is a very simple method because the circuit configuration is not complex but has a disadvantage that can not control phase and amplitude easily by using NCO. M/M method has the complexity of the circuit configuration because it requires the memories which stores the waveforms, the control circuits, and DAC. And this method should apply the high interface technology for being compatible with the wide bandwidth of the digital signal and has the difficulty for PCB design because the number of the signal lines should be increased according to the number of the data bits for DAC. Although it has several disadvantages, this method has the capability of pre-distortion function which can compensate the phase and amplitude characteristics of the system and also has an excellent advantage to make any arbitrary waveform, so this method is considered as an important technology with DDS method. This research describes the technological trends of the waveform generator for the SAR payload and analyzes the characteristics of the technology.

• 한국정밀공학회지
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• 제32권9호
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• pp.781-786
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• 2015

Recently, studies of 3D printing methods have been working in various applications. For example, the powder base method laminates the prints by using a binding or laser sintering method. However, the draw back of this method is that the post process is time consuming and does not allow for parts to be rapidly manufactured. The binding method requires the post process while the time required for the post process is longer than the manufacturing time. This paper proposes a UV curing binding method with an integrated piezo printing head system. The optimization of an arbitrary waveform generation for the control of a UV curable resin droplet was researched, in addition to developed optimized UV curing processes in multi nozzle ink jet heads.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.772-773
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• 2015

This paper presents a dynamic model of 2-D magnetostriction in electrical steel sheet (ESS) under rotating flux magnetization conditions and its implementation in finite element method (FEM). For an arbitrary waveform of magnetic flux density (B), the corresponding magnetostriction waveform can be predicted by the model. In order to apply the model to FEM easily, the model is based on trilinear interpolation method. As an example, the model is applied to a three-phase transformer constructed by highly grain-oriented electrical steel sheets and the numerical results by the magnetostriction model are discussed.

• ETRI Journal
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• 제43권4호
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• pp.640-649
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• 2021

In this paper, an additional degree of freedom in phased multi-input multi-output (phased-MIMO) radar with any arbitrary desired covariance matrix is proposed using space-time codes. By using the proposed method, any desired transmit covariance matrix in MIMO radar (phased-MIMO radars) can be realized by employing fully correlated base waveforms such as phased-array radars and simply extending them to different time slots with predesigned phases and amplitudes. In the proposed method, the transmit covariance matrix depends on the base waveform and space-time codes. For simplicity, a base waveform can be selected arbitrarily (ie, all base waveforms can be fully correlated, similar to phased-array radars). Therefore, any desired covariance matrix can be achieved by using a very simple phased-array structure and space-time code in the transmitter. The main advantage of the proposed scheme is that it does not require diverse uncorrelated waveforms. This considerably reduces transmitter hardware and software complexity and cost. One the receiver side, multiple signals can be analyzed jointly in the time and space domains to improve the signal-to-interference-plus-noise ratio.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제11B권4호
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• pp.164-168
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• 2001

In this paper voltage source FEA for hysteresis motor considering magnetic hysteresis characteristics is presented. The Preisach model is used as a hysteresis model. System matrix whose unknown variables are vector potentials and currents is formulated for voltage source. The stiffness matrix is maintained constant by using M-iteration method. Therefore the calculation time and efforts are reduced with Choleski direct method. Current waveform can be calculated for arbitrary voltage vaveform considering hysteresis effects.

• 한국전자파학회논문지
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• 제20권8호
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• pp.784-790
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• 2009

전방 감시 차량용 레이다에서 표적 거리와 속도 정보를 얻기 위해서는 일반적으로 주파수 변조된 연속파형(FMCW)이나 펄스 도플러(PD) 파형을 사용하고 있다. 그러나 고해상도의 표적 정보를 얻기 위해서는 펄스 폭이 매우 좁고 넓은 대역폭을 사용하여야 하므로 상대적으로 높은 첨두 전력이 필요하고 고속의 디지털 변환 처리속도가 요구된다. 본 논문에서는 계단 주파수 변조된 펄스 도들러 파형을 이용하여 고해상도의 표적 정보를 획득할 수 있는 SFPD(Stepped-frequency Pulsed-Doppler) 처리 기법을 제시한다. 제안된 SFPD 기법은 시뮬레이션을 통하여 기존의 FMCW 및 펄스 도플러 파형 방식과 비교 분석하였다. 본 기법은 필요에 따라서 거리 및 도플러 해상도를 가변할 수 있는 장점이 있기 때문에 이론적으로 고해상도의 표적 영상 형성이 가능하여 향후 정밀한 차량 충돌 방지를 위한 표적 식별에 활용할 수 있을 것으로 기대한다.

• 전자공학회논문지
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• 제50권2호
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• pp.174-184
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• 2013

LED 기반 그린에너지 조명 시스템의 성공적인 연구 개발과 원만한 설치 운영을 위해서는 펄스 파, 스파이크 파를 비롯한 비선형신호와 고조파, sag, swell 등을 포함한 불요신호에 대한 실시간 전력품질측정이 요구된다. 본 논문에서는 그린에너지 조명시스템 응용을 타깃으로 기존 저주파수 대 (60Hz~수KHz)는 물론 수십 KHz 이상의 고주파수 대에 발생하는 각종 전원 신호 분석이 가능한 저가형 전력품질측정 (power quality measurement: PQM) 방안을 제안하고, 이를 TI 320F28335 MCU(micro-controller unit) 기반 PQM 테스트 베드로 구현한다. 제안된 알고리즘은 CCS (Code Composer Studio) 3.3 환경에서 C언어로 작성하였으며, 임의 신호 발생기(NF-WF1974)로부터 발생된 모의 신호를 활용하여 구현된 알고리즘을 검증한다. 테스트 베드를 이용하여 LED SMPS로부터 발생되는 각종 비선형 전류 신호 측정, FFT를 이용한 고조파 신호의 분석이 가능할 뿐 아니라 이산 웨이블렛 변환을 이용한 sag, swell, interruption 등의 고품질 전력신호 측정도 가능하다.