• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1119-1122
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• 1990

Presnted is a new optical transmission system to transmit the FM control signal (80 MHz) through an optical fiber by the use of an inexpensive LED having a cutoff frequency of as low as 30 MHz. Studies are carried out on the division of the FM signal frequency at 80 MHz by a factor of four. The FM signal frequency is, after the transmission through the optical fiber, then multiplied by a factor of four so as to obtain the normal FM control signal.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.5
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• pp.33-40
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• 1998

In this paper, a design of current-mode continuous-time filters for low voltage and low frequency applications using complementary bipolar current mirrors is presented. The proposed current-mode filters consist of simple bipolar current mirrors and capacitors and are quite suitable for monolithic integration. Since the design method of the proposed current-mode filters are based on the integrator type of realization, it can be used for a wide range of applications. Since the input impedance of simple bipolar current mirror is small, in this paper, negative feedback amplifier is used to realize is designed by cascade method. The cutoff frequency of the designed filter can be easily tunable by the DC controlling current from 60kHz to 120kHz. The characteristics of the designed current-mode filters are simulated and examined by SPICE using standard bipolar transistor parameters.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.19-28
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• 1999

In this study, a real-time simulation system and a washout algorithm for an excavator have been developed for a driving simulator with six degrees of freedom. The excavator model consisting of a boom. bucket, upper frame, lower frame and four wheels, has total 11 degrees of freedom. The suggested washout algorithm consists of high and low pass filters with second order. The high pass filters cut off low frequency of the motion cues limited by platform motion. The cut off frequency for the tilt coordination are suggested for a realistic regeneration of excavator motion.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2189-2196
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• 2009

Theoretical analysis is presented for expending of the usable frequency range of optoelectronic mixing detection in the radio over fiber network system. We define the normalized gain to evaluate the performance of the optical mixing detection, and conform the possibilities of detection for the high frequency signals beyond the cutoff frequency of a photodiode. Optical mixing detection mechanism is analyzed by solving the continuity equation for the carriers of a photodiode. The normalized gain is independent on the signal frequency and the frequency difference between the optical signal and the local signal. Also, the amplitude of the local signal and the bias voltage are needed to be optimized at the same time in order to maximize the normalized gain.

• Journal of Home Health Care Nursing
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• v.15 no.1
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• pp.5-13
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• 2008

Purpose: The purpose of this study was to evaluate for the presence of posttraumatic stress disorder (PTSD)-related symptoms, anxiety, and depression after stroke. Eighty-four patients were enrolled between 2 and 12 months after their first ischemic or hemorrhagic stroke. Methods: PTSD symptoms were evaluated using the Impact of Event Scale (IES). The IES is a 15-item scale measuring intrusion and avoidance symptoms. The authors assessed mood alterations using the Hospital Anxiety and Depression Scale (HAD). The HAD is a brief, 14-item, self-reported questionnaire used to detect symptoms of anxiety (HADA) and depression (HADD). The survey data were analyzed using the SPSS 10.0 program. Frequency, mean, standard deviation, percentage t-test, and Pearson correlation coefficient were determined. Results: Twenty nine of the 84 (34.5%) patients scored higher than the cutoff for PTSD on the IES (IES>26). With use of the HAD scale, 44% of the patients reached the cutoff for anxiety ($HADA\;{\geq}8$). On the HSD scale, 44.1% of the patients reached the cutoff for depression ($HADD\;{\geq}8$). PTSD symptoms and anxiety were more frequent in women under age 39, without spouses, who had operations. Depression was more frequent in patients without spouses. There was a statistically significant correlation among posttraumatic stress symptoms, anxiety, and depression. Conclusion: There was statistically significant correlation among PTSD symptoms, anxiety, and depression in stroke patients. Therefore, it is necessary to develop nursing intervention for stroke patients with these clinical manifestations.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.667-670
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• 1998

Novel bipolar transresistance amplifier(TRA) for high-accuracy current-mode signal processing is described. The TRA consists of two current follower for the current inputs, a current summer for curent-differential, and a voltage follower for the voltage output. The simulation results show that the impedence of the current input and the voltage output is 0.5 $\Omega$ and the 3-dB cutoff frequency when used as a current to voltage converter extends beyond 40 MHz.

• Journal of Biomedical Engineering Research
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• v.12 no.1
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• pp.43-48
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• 1991

As the computerized methods and equipments In nuclear medicine imaging increases, quantitative information is needed on the single photon emission computed tomographic Images as well as on the conventional nuclear medicine images. In this paper, the authors investigated the effect of several clinician - friendly reconstrution filters on the resultant transverse slices of backprojected Profiles of radioisotope distribution from the Quantitative point of view, and reduced the filter parameters such as cutoff frequency and order of filter which are neces mary to minimize the quantification error using computer-generated phantoms.

• Journal of Biomedical Engineering Research
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• v.3 no.1
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• pp.51-54
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• 1982

As the computerized methods and equipments in nuclear medicine imaging increases, quantitative information is needed on the single photon emission computed tomographic images as well as on the conventional nuclear medicine images. In this paper, the authors investigated the effect of several clinician - friendly reconstrution filters on the resultant transverse slices of backprojected profiles of radioisotope distribution from the quantitative point of view, and reduced the filter Parameters such as cutoff frequency and order of filter which are necessary to minimize the quantification error using computer -generated phantoms.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.7-10
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• 1998

일반적으로 매우 낮은 차단주파수를 가지는 FIR 저역통과 필터의 경우 그 과도영역의 폭이 상대적으로 매우 좁기 때문에 긴 임펄스 응답을 가지게 되며, 따라서 많은 계산량을 필요로 하게 된다. 본 논문에서는, FIR 필터의 계수를 서브샘플링(subsampling)하여 계산량의 현저한 감소를 도모하고, 그로 인하여 발생하는 주파수 영역의 이미지를 IIR 필터를 사용하여 제거하는 기법을 제안한다. IIR 필터로 인하여 발생하는 위상의 왜곡은 앞단의 FIR 필터의 계수를 조절함으로써 상쇄시킬 수 있다. 제안된 알고리듬을 채택할 경우, 동일한 성능의 일반 FIR 필터에 비하여 사용하는 메모리의 양은 거의 같으나, 계산량은 수십분의 일까지 감소시킬 수 있다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.59-62
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• 2002

In this paper, low-pass filters using DGS-CPW cell are suggested. The bandwidth of stopband is extended up to 3 times of cutoff frequency. The novel DGS-CPW cell reduces the size of the circuit. This structure can be used in microwave and milimeter-wave circuits.