• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.80-87
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• 2013

A novel instrumentation amplifier(IA) using positive polarity current-conveyor(CCII+) for electronic measurement systems with low cost, wideband, and gain control with wide range is designed. The IA consists of two CCII+, three resistor, and an operational amplifier(op-amp). The principal of the operating is that the difference of two input voltages applied into two CCII+ used voltage and current follower converts into same currents, and then these current drive resistor of (+) terminal and feedback resistor of op-amp to obtain output voltage. To verify operating principal of the IA, we designed the CCII+ and used commercial op-amp LF356. Simulation results show that voltage follower used CCII+ has offset voltage of 0.21mV at linear range of ${\pm}$4V. The IA had wide gain range from -20dB to 60dB by variation of only one resistor and -3dB frequency for the gain of 60dB was 400kHz. The IA also has merits without matching of external resistor and controllable offset voltage using the other resistor. The power dissipation of the IA is 130mW at supply voltage of ${\pm}$5V.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.1
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• pp.15-24
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• 2012

In this paper, we suggest the dynamic-response-free SMPS using a new high-resolution DPWM generator based on switched-capacitor delay technique. In the proposed system, duty ratio of DPWM is controlled by voltage slope of an internal capacitor using switched-capacitor delay technique. In the proposed circuit, it is possible to track output voltage by controlling current of the internal capacitor of the DPWM generator through comparison between the feedback voltage and the reference voltage. Therefore the proposed circuit is not restricted by the dynamic-response characteristic which is a problem in the existing SMPS using the closed-loop control method. In addition, it has great advantage that ringing phenomenon due to overshoot/undershoot does not appear on output voltage. The proposed circuit can operate at switching frequencies of 1MHz~10MHz using internal operating frequency of 100 MHz. The maximum current of the core circuit is 2.7 mA and the total current of the entire circuit including output buffer is 15 mA at the switching frequency of 10 MHz. The proposed circuit has DPWM duty ratio resolution of 0.125 %. It can accommodate load current up to 1 A. The maximum ripple of output voltage is 8 mV. To verify operation of the proposed circuit, we carried out simulation with Dongbu Hitek BCD $0.35{\mu}m$ technology parameter.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.6-14
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• 2011

The fast growing of the number of users requires the development of reliable communication systems able to provide higher data rates. In order to meet those requirements, techniques such as Multiple Input Multiple Out (MIMO) and Orthogonal Frequency Division multiplexing (OFDM) have been developed in the recent years. In order to combine the benefits of both techniques, the research activity is currently focused on MIMO-OFDM systems. In addition, for a fast wireless channel environment, the data rate and reliability can be optimized by setting the modulation and coding adaptively according to the channel conditions; and using sub-carrier frequency, and power allocation techniques. Depending on how accurate the feedback-based system obtain the channel state information (CSI) and feed it back to the transmitter without delay, the overall system performance would be poor or optimal. In this paper, we propose a Signal to Noise Ratio (SNR) estimation algorithm where the preamble is known for both sides of the transciever. Through simulations made over several channel environments, we prove that our proposed SNR estimation algorithm is more accurate compared with the traditional SNR estimation. Also, We applied AMC on several channel environments using the parameters of IEEE 802.11n, and compared the Throughput performance when using each of the different SNR Estimation Algorithms. The results obtained in the simulation confirm that the proposed algorithm produces the highest Throughput performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5541-5549
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• 2015

This paper introduces a safer and more power efficient heater by using induction heating, to apply to the semiconductor wafer fabrication exhaust gas cleaning system. The exhaust gas cleaning system is currently made with filament heater that generates an endothermic reaction of N2 gas for the removal of moisture. Induction theory, through the bases of theoretical optimization and electronic implementation, is applied in the design of the induction heater specifically for the semiconductor wafer exhaust system. The new induction heating design provides a solution to the issues with the current energy inefficient, unreliable, and unsafe design. A robust and calibrated design of the induction heater is used to optimize the energy consumption. Optimization is based on the calibrated ZVS induction circuit design specified by the resonant frequency of the exhaust pipe. The fail-safe energy limiter embedded in the system uses a voltage regulator through the feedback of the MOSFET control, which allows the system performance to operate within the specification of the N2 Heater unit. A specification and performance comparison from current conventional filament heater is made with the calibrated induction heater design for numerical analysis and the proof of a better design.

• Journal of Radiation Protection and Research
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• v.38 no.1
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• pp.1-9
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• 2013

Education and training is an important means of promoting safety culture and enhancing the level of competence of radiation worker in radiation protection. The existing international nuclear education and training of short duration has been carried out on the high-level officials and focussed on the classroom based training. The developing countries has been asking for support to cultivate their own technical experts to Korea which is a donor country exporting nuclear power plants. This paper summarizes the results of developing and operating the international education and training course to froster technical experts in radiation protection that emphasized practical training sessions and technical visits using the excellent domestic radiation facilities and infrastructure of education and training. It mentions the procedures of assessment and feedback as well. In an effort to maximize teaching-learning effects and to maintain consistency of the learning objectives, methods and assessment, SAT methodology has been applied on the processes of developing and operating the course. In the comparative and final assessment which were conducted at the beginning or at the end of training course, participants' average score increased around 2 points. The questionnaire of participants showed a high level of satisfaction of 4.0 points or above for the most of the questions. These imply teaching-learning methods applied to it might be effective. The teaching-learning methodologies may provide the opportunity to develop the customized training course for bringing up international technical experts and to shift educational paradigm from theory-oriented to on-site practice-based education.

• Journal of Technologic Dentistry
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• v.35 no.2
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• pp.157-171
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• 2013

Purpose: This study aims to present a database for the development of a healthcare management program based on the survey and analysis of self reported psychosomatic symptoms among the current dental technology students. Methods: Subjects of our study are 480 dental technology major students enrolled in a third year college located Gyeonggi, Chungcheong, and Gangwon province. Using a random sampling, we conducted a self-report survey from August 30, 2011 to October 28, 2011 and 418 reports were collected as feedback and we put an analysis on them. Results: 1. The average physical self symptom was 20.49, which is higher than the average mental self symptom(18.54). Of the subcategories of psychosomatic self symptom, we observed multiple subjective symptoms as the highest one(37.77), and aggression as the lowest(13.77). 2. As to gender, both physical and mental self symptom were statistically significant with the scale score of(p<.001). The scale score of subcategories is as follows; multiple subjective symptoms(I, p<.001), eye and skin(B, p<.001), digestive(C, p<.001), impulsiveness(H, p<.001), lie scale(L, p<.001), mental instability(J, p<.001), depression(K, p<.001), aggression(F, p<.001), irregularity of life(G, p<.001), mouth and anal(D, p<.05), nervousness(E, p<.05). 3. As for obesity, statistical significance was shown with the scale scores of physical self symptom(p<.001), multiple subjective symptoms(I, p<.001), digestive(C, p<.001), aggression(F, p<.001), depression(K, p<.01), irregularity of life(G, p<.01), respiratory(A, p<.05), eye and skin(B, p<.05), impulsiveness(H, p<.05), mental instability(J, p<.05). The scale scores in the environmental quality and life satisfaction were shown as follows; depression(K, p<.001), lie scale(L, p<.01), and irregularity of life(G, p<.05). 4. We employed multiple regression analysis to take account of general factors affecting psychosomatic self symptoms, and drew that the explanatory power of the model was proved with the scales of physical self symptom(4.1%) and mental self-symptom(3.6%). Obesity was a factor that affects physical self symptom with the scale score of(p<.01), and environmental quality and life satisfaction(p<.01) and obesity(p<.05) affect mental self symptom. Conclusion: In this analysis we observed obesity of dental technology students can influence their psychosomatic self symptoms. In this sense, it would be reasonable to develop a healthcare management and education programs that help the students maintain a healthy weight and promote their health.

• Journal of Korea Society of Industrial Information Systems
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• v.21 no.1
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• pp.61-70
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• 2016

This paper describes a new PMU(parametric measurement unit) design technique for automatic test equipment(ATE). Only one DDA(differential difference amplifier) is used to force the test signals to DUT(device under test), while conventional design uses two or more amplifiers to force test signals. Since the proposed technique does not need extra amplifiers in feedback path, the proposed PMU inherently guarantees stable operation. Moreover, to measure the response signals from DUT, proposed technique also adopted only one DDA amplifier as an IA(instrument amplifier), while conventional IA uses 3 amplifiers and several resistors. The DDA adopted two rail-to-rail differential input stages to handle full-range differential signals. Gain enhancement technique is used in folded-cascode type DDA to get open loop gain of 100 dB. Proposed PMU design enables accurate and stable operation with smaller hardware and lower power consumption. This PMU is implemented with 0.18 um CMOS process and supply voltage is 1.8 V. Input ranges for each force mode are 0.25~1.55 V at voltage force and 0.9~0.935 V at current force mode.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.59-67
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• 2016

A novel instrumentation amplifier (IA) using fully-differential linear operational transconductance amplifier (FLOTA) for electronic measurement systems with low cost, wideband, and gain control with wide range is designed. The IA consists of a FLOTA, two resistor, and an operational amplifier(op-amp). The principal of the operating is that the difference of two input voltages applied into FLOTA converts into two same difference currents, and then these current drive resistor of (+) terminal and feedback resistor of op-amp to obtain output voltage. To verify operating principal of the IA, we designed the FLOTA and realized the IA used commercial op-amp LF356. Simulation results show that the FLOTA has linearity error of 0.1% and offset current of 2.1uA at input dynamic range ${\pm}3.0V$. The IA had wide gain range from -20dB to 60dB by variation of only one resistor and -3dB frequency for the 60dB was 10MHz. The proposed IA also has merits without matching of external resistor and controllable offset voltage using the other resistor. The power dissipation of the IA is 105mW at supply voltage of ${\pm}5V$.

• The Journal of Korean society of community based occupational therapy
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• v.3 no.1
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• pp.33-42
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• 2013

Objective : The purpose of this study is to assess effects of Robot-assisted therapy on function of upper extremity in stroke patients. Method : A total of 11 patients suffered from stroke participated in this study. Inpatients of 4 people and outpatients of 7 people divided by 12 months conducted Robot-assisted therapy for 5~6 weeks. Therapists selected appropriate exercise mode to patients, and patients Patients performed the reaching exercise was repeated with looking monitor provided 3-dimensional feedback. Before and after treatment of upper extremity functions was compare by Wolf Motor Function(K-WMFT), Box & Block Test(BBT), Dynamometer, average execution time. Result : Grip power, K-WMFT, BBT, average performance times were promoting in all subjects, and only showed statistically significant changes in outpatients. But outpatients did not show statistically significant changes in inpatients. Conclusion : Robotic-assisted therapy in stroke patients have a positive impact on upper extremity function that could confirm that. In the future, Robots-assisted therapy is expected to be useful for stroke patients in the area of occupational therapy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.17-24
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• 2009

This paper deals with the cancellation performance of loop back interference signal in the case of multihop relay of 16-QAM received signal at the USN radio network. For this, it is necessary to the exchange of information with long distance located station by means of the relay function between the node in the USN environment. In the relay node, the loop-back interference signal which the retransmitting signal is feedback to the receiver side due to the antenna of transmitter and receiver are co-used or very colsely located or using the nonlinear device. Due to this signal, the performance of USN system are degraded which are using the limited resource of frequency and power. For improve this, it is necessary to applying the adaptive signal processing algorithm in order to cancellating the unwanted loop-back interference signal at the frontend of receiver in relaying node, we can get the better system and multi hop performance. In the adaptive signal processing, we considered the 16-QAM signal which has a good spectral efficiency, firstly, than, the QR-Array RLS algorithm was used that has a fairly good convergence property and the solving the finite length problem in the H/W implementation. Finaly, we confirmed that the good elimination performanc was confirmed by computer simulation in the learing cuved and received signal constellation compared to the conventional RLS.