• Asian Pacific Journal of Cancer Prevention
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• 제16권1호
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• pp.355-361
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• 2015

Background: Deletion types of genetic variants of glutathione S-transferase (GST) M1 and T1, the GSTM1 null and GSTT1 null which are risk factors for certain cancers, have been ubiquitously found in human populations but their worldwide distribution pattern is unclear. Materials and Methods: To perform a meta-analysis, a systematic search for the literature on GSTM1 and GSTT1 null genotypes was done to identify 63 reports for 81 human populations. Relationships between the GSTM1 and GSTT1 null genotype frequencies and the absolute latitude of 81 populations were tested by Spearman's rank correlation coefficient. Results: A significant positive correlation was detected between the GSTM1 null genotype frequency and the absolute latitude (r=0.28, p-value <0.05), whereas the GSTT1 null genotype frequency and absolute latitude showed a significant negative correlation (r= -0.41 p-value <0.01). There was no correlation between the frequencies of GSTM1 and GSTT1 null genotype in each population (r= -0.029, p-value=0.80). Conclusions: Latitudinal clines of the distribution of the GSTM1 and GSTT1 null genotypes may be attributed to the result of gene-environmental adaptation. No functional compensation between GSTM1 and GSTT1 was suggested by the lack of correlation between the null frequencies for GSTM1 and GSTT1.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권11호
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• pp.654-659
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• 2005

An improved power supply for APD(Avalanche Photo Diode) with a received optical power monitoring circuit allows the received optical power increase temporary without of the degradation of the electrical signal. For the cost reduction and simple fabrication, an improved power supply has been proposed that it was designed for driving a APD as a receiving device of a wireless optical transmission system. It was demonstrated that it was possible to improve a dynamic range by compensating the temperature coefficient of the APD up to 1.0 V/$^{\circ}C$ through the power supply. Also, for an efficient transmission at the receiver end, a simple structure of a single cylindrical micro-lens configuration was used in conjunction with the laser diode to partially compensate a laser beam ellipticity. For this purpose, an astigmatism introduced by the micro-lens is utilized for the additional compensation of the beam ellipticity at the receiver end. In this paper, it is demonstrated that an efficient beam shaping is realized by using the proposed configuration consisting of the single lens attached to the laser diode.

• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.389-396
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• 2016

The sealing robot must be able to calculate the slope of a contact surface for complete adherence of the sealing on different concrete shapes. After the slope is obtained, the robot will track on the surface of the concrete, but this process contains an error in the actual purpose of the force command. The reason this a phenomenon occurs, the non-linearity of the contact surface and the end-effector, is due to parasitic coupling. Errors like make it difficult to measure accurately the respective factors. Therefore, it is regarded as a disturbance that occurs when it follows the work surface it. In this paper, we selected the friction coefficient of the surface as a control factor and designed a compensator to reduce effects of disturbance. Finally, in view of the non-linearity of the end-effector of a robot to contact surfaces directly, we propose a robust force tracking controller in the finite range for managing disturbances that occur during the sealing.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권4호
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• pp.528-533
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• 2016

A low voltage high PSRR CMOS Bandgap circuit capable of generating a stable voltage of less than 1 V (0.8 V and 0.5 V) robust to Process, Voltage and Temperature (PVT) variations is proposed. The high PSRR of the circuit is guaranteed by a low-voltage current mode regulator at the central aspect of the bandgap circuitry, which isolates the bandgap voltage from power supply variations and noise. The isolating current mirrors create an internal regulated voltage $V_{reg}$ for the BG core and Op-Amp rather than the VDD. These current mirrors reduce the impact of supply voltage variations. The proposed circuit is implemented in a $0.35{\mu}m$ CMOS technology. The BGR circuit occupies $0.024mm^2$ of the die area and consumes $200{\mu}W$ from a 5 V supply voltage at room temperature. Experimental results demonstrate that the PSRR of the voltage reference achieved -118 dB at frequencies up to 1 kHz and -55 dB at 1 MHz without additional circuits for the curvature compensation. A temperature coefficient of $60 ppm/^{\circ}C$ is obtained in the range of -40 to $120^{\circ}C$.

• 한국환경과학회지
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• 제24권8호
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• pp.1075-1084
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• 2015

This study was conducted to investigated the changes in the nutrient components ($NO_3{^-}-N$, $NH_4{^+}-N$, $PO_4{^{3-}}P$, $K^+$, $Ca^{2+}$, and $Mg^{2+}$) and environmental parameters (electrical conductivity, total dissolved solids and pH) on the leaf lettuce (Lactuca sativa L.) grown with hydroponics. Recirculating hydroponic cultivation system was consisted of planting port, LED lamp, water tank, and circulating pump for hydroponic. Nutrient solution was used in the standard solution for Japan vegetables experimental station and commercial hydroponic. The result showed that electrical conductivity (EC), total dissolved solids (TDS) and pH, depending on the growth of lettuce decreased continuously. With the growth of the lettuce, nitrate nitrogen, ammonia nitrogen, phosphate phosphorus were required for periodic replacement. The number of pH compensation due to the growth of lettuce are the most high. The concentration of $Ca^{2+}$ and $Mg^{2+}$ during the lettuce growth showed no significant change. However, $K^+$ concentration increased due to the replacement with nitrogen and phosphorus. Electric conductivity and total dissolved solids with total nutrient concentration showed the linear relationship and the correlation coefficient $R^2$ were 0.8601 and the 0.827, respectively.

• 한국운동역학회지
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• 제31권3호
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• pp.168-175
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• 2021

Objective: To investigate the static and dynamic analysis of ankle joint complex between subjects with chronic ankle instability (CAI) and healthy controls. Method: A total of 38 subjects and CAI group (N=19) and healthy control (N=19) participated in this first study. Variables that were measured in this study were as follows: 1) Subtalar joint axis inclination and deviation 2) Rearfoot angle 3) Navicular drop test 4) Heel alignment view in alignment analysis. Intra Correlation Coefficient (ICC) is used for reliability. A secondary 17 subjects are recruited including 9 of CAI and healthy for gait analysis between group. Lower extremity sagittal, frontal, and transverse kinematics were measured. All data were analyzed to ensemble curve analysis. Results: 1) There were statistically significant differences in standing rearfoot, navicular drop, heel alignment view, subtalar joint (STJ) inclination and deviation. 2) Only in sagittal, meaningful difference is showed during walking in gait analysis. Conclusion: Morphological problem can affect ankle sprain in aspect of structure with no relation to compensation of neuromuscular.

• Smart Structures and Systems
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• 제33권1호
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• pp.41-53
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• 2024

Grouting sleeves are an essential connecting component of prefabricated components, and the quality of grouting has a significant influence on structural integrity and seismic performance. The embedded grouting sleeve (EGS)'s grouting defects are highly undetectable and random, and no effective monitoring method exists. This paper proposes an ultrasonic guided wave method and provides a set of guidelines for selecting the optimal frequency and suitable period for the EGS. The optimal frequency was determined by considering the group velocity, wave structure, and wave attenuation of the selected mode. Guided waves are prone to multi-modality, modal conversion, energy leakage, and dispersion in the EGS, which is a multi-layer structure. Therefore, a time-reversal (TR)-based multi-mode focusing and dispersion automatic compensation technology is introduced to eliminate the multi-mode phase difference in the EGS. First, the influence of defects on guided waves is analyzed according to the TR coefficient. Second, two major types of damage indicators, namely, the time domain and the wavelet packet energy, are constructed according to the influence method. The constructed wavelet packet energy indicator is more sensitive to the changes of defecting than the conventional time-domain similarity indicator. Both numerical and experimental results show that the proposed method is feasible and beneficial for the detection and quantitative estimation of the grouting defects of the EGS.

• 대한전자공학회논문지SP
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• 제45권3호
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• pp.80-92
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• 2008

기존의 영상 부호화 표준들보다 높은 압축 성능을 얻기 위해 부호화 효율 측면에서 우수한 기술들이 가장 최근에 완성된 영상 부호화 표준인 H.264/AVC에 채택되었다. 가변 블록 단위의 움직임 예측/보상과 다양한 방향성을 통한 화면 내 예측 방법 등의 영상 부호화 기술들의 발달에도 불구하고, 이산 여현 변환은 초기 영상 부호화 표준에서부터 계속적으로 사용되고 있다. 일반적으로 실제 영상 신호가 부호화될 때 생성되는 잔여 신호의 상관 계수 값은 0.5 미만이다. 하지만, 이러한 상관 계수 값의 범위는 이산 여현 변환이 최적의 성능을 나타내는 범위가 아니며, 상관 계수의 범위가 -0.5에서 0.5일 경우 차선의 변환인 이산 정현 변환이 이산 여현 변환과 함께 영상 호화에 사용될 수가 있다. 본 논문에서는 이산 정현 변환과 H.264/AVC에서의 정수 여현 변환 중 최적의 변환을 율-왜곡 최적화 과정을 이용하여 선택적으로 사용하는 선택 변환을 제안한다. 제안하는 방법을 통해 H.264/AVC의 JM 10.2와 비교하여 상대적으로 높은 비트율에서 최대 0.71 dB의 BD-PSNR 향상을 얻을 수가 있었다.

• 한국운동역학회지
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• 제29권3호
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• pp.157-166
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• 2019

Objective: This study examined the effects of stimulating fingertip temperature on the patterns of force sharing and stability properties during multi-finger force production tasks. Method: 9 adult subjects (male: 3, female: 6, age: $26.11{\pm}4.01yrs$, height: $169.22{\pm}5.97cm$, weight: $61.44{\pm}11.27kg$) participated in this study. The experiment consisted of three blocks: 1) maximal voluntary contraction (MVC) task, 2) single-finger ramp task to quantify enslaving (i.e., unintended force production by non-task fingers), and 3) 12 trials of multi-finger steady-state force production task at 20% MVC. There were three temperature conditions including body-temperature (i.e., control condition), $40^{\circ}C$, and $43^{\circ}C$, and the stimulation was given to the index finger only for all experimental conditions. Results: There were no significant differences in the MVC forces, enslaving, and the accuracy of performance during the steady-state task between the conditions. However, the share of stimulated index finger force increased with the index fingertip temperature, while the share of middle finger force decreased. Also, the coefficient of variation of both index and middle finger forces over repetitive trials increased with the index fingertip temperature. Under the framework of the uncontrolled manifold (UCM) hypothesis used to quantify indices of multi-finger synergies (i.e., stability property) stabilizing total force during the steady-state task, the two variance components within the UCM analysis increased together with the fingertip temperature, while no changes in the synergy indices between the conditions. Conclusion: The current results showed that fingertip temperature stimulation only to index finger does not affect to muscle force production capability of multi-finger, independence of individual fingers, and force production accuracy by the involvement of all four fingers. The effect of fingertip temperature on the sharing pattern and force variation may be due to diffuse reflex effects of the induced afferent activity on alpha-motoneuronal pools. However, the unchanged stability properties may be the reflection of the active error compensation strategies by non-stimulated finger actions.

• 산업경영시스템학회지
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• 제46권3호
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• pp.15-22
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• 2023

BNKT Ceramics, one of the representative Pb free based piezoelectric ceramics, constitutes a perovskite(ABO3) structure. At this time, the perovskite structure (ABO3) is in the form where the corners of the octahedrons are connected, and in the unit cell, two ions, A and B, are cations, A ion is located at the body center, B ion is located at each corner, and an anion O is located at the center of each side. Since Bi, Na, and K sources constituting the A site are highly volatile at a sintering temperature of 1100℃ or higher, it is difficult to maintain uniformity of the composition. In order to solve this problem, there should be suppression of volatilization of the A site material or additional compensation of the volatilized. In this study, the basic composition of BNKT Ceramics was set to Bi_0.5(Na_0.78K_0.22)_0.5TiO₃ (= BNKT), and volatile site (Bi, Na, and K sources) were coated in the form of a shell to compensate additionally for the A site ions. In addition, the physical and electrical properties of BNKT and its coated with shell additives(= @BNK) were compared and analyzed, respectively. As a result of analyzing the crystal structure through XRD, both BNKT(Core) and @BNK(Shell) had perovskite phases, and the crystallinity was almost similar. Although the Curie temperature of the two sintered bodies was almost the same (TC = 290 ~ 300 ℃), it was confirmed that the d33 (piezoelectric coefficient) and Pr (residual polarization) values were different. The experimental results indicated that the additional compensation for a shell additive causes the coarsening, resulting in a decrease in sintering density and Pr(remanent polarization). However, coating shell additives to compensate for A site ion is an effective way to suppress volatilization. Based on these experimental results, it would be the biggest advantage to develop an eco-friendly material (Lead-free) that replaced lead (Pb), which is harmful to the human body. This lead-free piezoelectric material can be applied to a biomedical device or products(ex. earphones (hearing aids), heart rate monitors, ultrasonic vibrators, etc.) and skin beauty improvement products (mask packs for whitening and wrinkle improvement).