• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.27 no.1
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• pp.13-20
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• 2021

Background: The serratus anterior and upper trapezius muscles act synergistically to allow for an appropriate scapulothoracic rhythm. However, a decrease in serratus anterior activation causes the upper trapezius to become overactivated, resulting in dysfunction. This study compared serratus anterior and upper trapezius muscle activity according to sling angle and compared serratus anterior strength between healthy adults and patients with shoulder instability. Methods: Twenty participants (10 healthy adults and 10 patients with shoulder instability) were included in this study. The participants had their arms extended at sling angles of 30°, 60°, and 90° in reach forward with shoulder flexion using goniometer. Serratus anterior strength was measured three times while the participants were supine. The outcome measures were surface electromyography amplitude of the upper trapezius and serratus anterior and serratus anterior strength. Results: The Wilcoxon signed-rank test indicated that the upper trapezius was significantly different between healthy group and shoulder instability group at a sling angle of 60°, and both the upper trapezius and serratus anterior exhibited significant differences at 90°. Moreover, a significant difference was noted in the muscle strength of the serratus anterior. Conclusion: Our results provide novel and promising clinical evidence that patients with shoulder instability have decreased serratus anterior activation and upper trapezius overactivation, resulting in muscle imbalance. In addition, there was a significant difference between the healthy group and shoulder instability group in the serratus anterior muscle strength

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.11
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• pp.94-100
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• 2014

In this paper, a design of low power Current-Reuse Voltage Controlled Oscillator (VCO) which has wide tuning range about 1.95 GHz ~ 3.15 GHz is presented. Class-C type is applied to improve phase noise and 2-Step Auto Amplitude Calibration (AAC) is used for minimizing the imbalance of differential VCO output voltage which is main issue of Current-Reuse VCO. The mismatch of differential VCO output voltage is presented about 1.5mV ~ 4.5mV. This mismatch is within 0.6 % compared with VCO output voltage. Proposed Current-Reuse VCO is designed using CMOS $0.13{\mu}m$ process. Supply voltage is 1.2 V and current consumption is 2.6 mA at center frequency. The phase noise is -116.267 dBc/Hz at 2.3GHz VCO frequency at 1MHz offset. The layout size is $720{\times}580{\mu}m^2$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.6
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• pp.573-582
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• 2010

In this paper, X-band transceiver for high resolution wideband SAR systems is designed and fabricated. Also as a technique for enhancing the performance, error compensation algorithm is presented. The transceiver for SAR system is composed of transmitter, receiver, switch matrix and frequency generator. The receiver especially has 2 channel mono-pulse structure for ground moving target indication. The transceiver is able to provide the deramping signal for high resolution mode and select the receive bandwidth for receiving according to the operation mode. The transceiver had over 300 MHz bandwidth in X-band and 13.3 dBm output power which is appropriate to drive the T/R module. The receiver gain and noise figure was 39 dB and 3.96 dB respectively. The receive dynamic range was 30 dB and amplitude imbalance and phase imbalance of I/Q channel was ${\pm}$0.38 dBm and ${\pm}$3.47 degree respectively. The transceiver meets the required electrical performances through the individual tests. This paper shows the pulse error term depending on SAR performance was analyzed and range IRF was enhanced by applying the compensation technique.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1097-1106
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• 2011

In this paper, we present design method of wideband single-sideband mixer(SSM) with excellent sideband suppression and carrier suppression. We proposed SSM with 4-band split structure for uniform output flatness. From circuit simulation of this structure using Microwave OfficeTM, we got satisfactory results. We realized a SSM based on this results, then we experimented. The measured results show excellent agreements with the simulated results. We compared with two SSM's(target SSM(M Co. SM0218LC1CDC SSM) and our SSM) as well. The presented SSM is 3.35 times bigger, but sideband suppression is 3 dBc better and carrier suppression is 8 dBc better than those of comparative SSM, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.335-342
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• 2012

A high-isolation Ka-band WR-28 waveguide power combiner is designed and implemented using a resistive septum. The waveguide power combiner developed here is an E-plane T-junction type with a TaN resistive septum inserted in a slit of waveguide junction. The fabricated waveguide power combiner shows a return loss better than -20 dB and an insertion loss less than 0.1 dB. Also the measurement shows isolation levels of 20 dB or more almost all over the band and in particular 25 dB or more below 37 GHz. The amplitude and phase imbalance are measured to be less than 0.1 dB and $2.5^{\circ}$, respectively.

• The Journal of the Acoustical Society of Korea
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• v.13 no.4
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• pp.50-59
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• 1994

The pan-european paging system European Radio MEssage System (ERMES), a new system of digital information communication, has 16 channels with 25KHz channel spacing. The ERMES modulation format is 4-PAM/FM. The ERMES operates in the frequency range 169.4125MHz$\~$169.8125MHz. In this paper, an ERMES receiving system according to the European Telecommunication Standard Institute(ETSI) specfication with a double error correction capability is designed. The ERMES receiver system is designed with the conventional circuit and its error performance for muitiple signal modulated by the 4-PAM/FM method are analyzed. Since amplitude imbalance among the signal components can impair the system performance when several receivers are operated on the same RF channel simultaneously, the optimal parameters are obtained in designing the radio system. Performance of the proposed receiver system is verified via computer simulation for processing procedure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.558-565
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• 2013

In this paper, modeling and simulation for performance analysis of high resolution SAR system has been carried out in the time, frequency and numeric domain using ADS Ptolemy simulation tool of Agilent corporation. SAR system consists of antenna, controller and transceiver. Error parameters affecting SAR system performances have been defined, modeled and simulated such as phase noise of frequency synthesizer, amplitude and phase characteristic of TWTA, sampling frequency of waveform generator and I/Q imbalance. Finally, the development requirements of SAR system based on the impulse response function have been derived.

• Smart Structures and Systems
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• v.22 no.2
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• pp.185-192
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• 2018

Participants in the Asia Pacific Conference of the Prognostics and Health Management Society 2017 (PHMAP 2017) Data Challenge were given measured vibration signals from motor-driven gearboxes used in pulverizers. Using this information, participants were requested to predict failure dates and the faulty components. The measured signals were affected by significant noise and disturbance, as the pulverizers in the provided data worked under actual operating conditions. This paper thus presents a fault prediction method for a motor-driven gearbox in a pulverizer system that can perform under external noise and disturbance conditions. First, two fault features, an RMS value in the higher frequency zones (HRMS) and an amplitude of a period for high-speed shaft in the quefrency domain ($QA_{HSS}$), were extracted based on frequency analysis using the higher and lower sampling rate data. The two features were then applied to each pulverizer based on results of frequency responses to impact loadings. Then, a regression analysis was used to predict the failure date using the two extracted features. A weighted regression analysis was used to compensate for the imbalance of the features in the given period. In addition, the faulty components in the motor-driven gearboxes were predicted based on the modulated frequency components. The score predicted by the proposed approach was ranked first in the PHMAP 2017 Data Challenge.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.35-40
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• 2008

This paper proposes a dual-band balun which is based on Wilkinson power divider. By inserting $\lambda/2$ transmission line between port 2 and 3, this balun shows good matching at all ports and improved isolation. We use matamaterial(CRLH, D-CRLH) structure for a miniaturization of the circuit implementation and dual-band operation at TDMB frequency range(195MHz) and DVB-H frequency range(670MHz). The proposed balun is designed with return loss larger than -12.98dB at all port, and isolation larger than -12.4dB, the amplitude imbalance between output signals less than 0.08dB, also phase differences of outputs less than $2.8^{\circ}$.

• Korean Journal of Cognitive Science
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• v.35 no.1
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• pp.49-95
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• 2024

Polygraph examination, statement validity analysis and P300-based concealed information test are major three examination tools, which are use to determine a person's truthfulness and credibility in criminal procedure. Although polygraph examination is most common in criminal procedure, but it has little admissibility of evidence due to the weakness of scientific basis. In 1990s to support the weakness of scientific basis about polygraph, Farwell and Donchin proposed the P300-based concealed information test technique. The P300-based concealed information test has two strong points. First, the P300-based concealed information test is easy to conduct with polygraph. Second, the P300-based concealed information test has plentiful scientific basis. Nevertheless, the utilization of P300-based concealed information test is infrequent, because of the quantity of probe stimulus. The probe stimulus contains closed information that is relevant to the crime or other investigated situation. In tradition P300-based concealed information test protocol, three or more probe stimuli are necessarily needed. But it is hard to acquire three or more probe stimuli, because most of the crime relevant information is opened in investigative situation. In addition, P300-based concealed information test uses oddball paradigm, and oddball paradigm makes imbalance between the number of probe and irrelevant stimulus. Thus, there is a possibility that the unbalanced number of probe and irrelevant stimulus caused systematic underestimation of P300 amplitude of irrelevant stimuli. To overcome the these two limitation of P300-based concealed information test, one-probe P300-based concealed information test protocol is explored with various machine learning algorithms. According to this study, parameters of the modified one-probe protocol are as follows. In the condition of female and male face stimuli, the duration of stimuli are encouraged 400ms, the repetition of stimuli are encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. In the condition of two-syllable word stimulus, the duration of stimulus is encouraged 300ms, the repetition of stimulus is encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. It was also conformed that the logistic regression (LR), linear discriminant analysis (LDA), K Neighbors (KNN) algorithms were probable methods for analysis of P300 amplitude. The one-probe P300-based concealed information test with machine learning protocol is helpful to increase utilization of P300-based concealed information test, and supports to determine a person's truthfulness and credibility with the polygraph examination in criminal procedure.