• 항공우주기술
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• 제4권2호
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• pp.117-125
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• 2005

관성항법유도장치는 관성센서 출력에 대한 측정 정밀도를 향상시키기 위해 자이로 및 가속도계의 아날로그 출력을 주파수로 변환해주는 AF(Analog to Frequency) 변환기를 사용한다. AF 변환기 측정 신뢰성을 보장하기 위해서는 신중한 교정절차가 결정되어야 하며, 교정절차에 의한 교정시험은 주기적으로 수행되어야 한다. 본 논문에서는 양ㆍ음의 입력에 대해 각각 양ㆍ음 리셋전류를 갖는 synchronous charge balance type의 AF 변환기 교정방법에 대해 다루었다. AF 변환기 교정은 AF 변환기 환산계수 오차 교정 시험과 바이어스 교정시험으로 나누어 수행되었으며, 교정 시험용 프로그램에 의해 자동으로 수행되었다.

• 한국농공학회논문집
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• 제54권4호
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• pp.65-71
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• 2012

The objective of this study was to estimate surface runoff from rice paddy plots using an artificial neural network (ANN). A field experiment with three treatment levels was conducted in the NICS saemangum experimental field located in Iksan, Korea. The ANN model with the optimal network architectures, named Paddy1901 with 19 input nodes, 1 hidden layer with 16 neurons nodes, and 1 output node, was adopted to predict surface runoff from the plots. The model consisted of 7 parameters of precipitation, irrigation rate, ponding depth, average temperature, relative humidity, wind speed, and solar radiation on the daily basis. Daily runoff, as the target simulation value, was computed using a water balance equation. The field data collected in 2011 were used for training and validation of the model. The model was trained based on the error back propagation algorithm with sigmoid activation function. Simulation results for the independent training and testing data series showed that the model can perform well in simulating surface runoff from the study plots. The developed model has a main advantage that there is no requirement for any prior assumptions regarding the processes involved. ANN model thus can be a good tool to predict surface runoff from rice paddy fields.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E3호
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• pp.75-85
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• 2005

A mathematical sensitivity analysis of the flow-through dynamic flux chamber technique, which has been utilized usually for various trace gas flux measurement from soil and water surface, was performed in an effort to provide physical and mathematical understandings of parameters essential for the NO flux calculation. The mass balance equation including chemical reactions was analytically solved for the soil NO flux under the steady state condition. The equilibrium concentration inside the chamber, $C_{eq}$, was found to be determined mainly by the balance between the soil flux and dilution of the gas concentration inside the chamber by introducing the ambient air. Surface deposition NO occurs inside the chamber when the $C_{eq}$ is greater than the ambient NO concentration ($C_{0}$) introducing to the chamber; NO emission from the soil occurs when the $C_{eq}$ is less than the ambient NO concentration. A sensitivity analysis of the significance of the chemical reactions of NO with the reactive species (i.e. $HO_{2},/CH_{3}O_{2},/O_{3}$) on the NO flux from soils was performed. The result of the analysis suggests that the NO flux calculated in the absence of chemical reactions and wall loss could be in error ranges from 40 to $85\%$ to the total flux.

• Journal of Power Electronics
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• 제14권6호
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• pp.1178-1188
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• 2014

This study proposes a finite-state model predictive controller to regulate the load current and balance the DC-link capacitor voltages of a four-leg neutral-point-clamped converter. The discrete-time model of the converter, DC-link, inductive filter, and load is used to predict the future behavior of the load currents and the DC-link capacitor voltages for all possible switching states. The switching state that minimizes the cost function is selected and directly applied to the converter. The cost function is defined to minimize the error between the predicted load currents and their references, as well as to balance the DC-link capacitor voltages. Moreover, the current regulation performance is improved by using a two-step prediction horizon. The feasibility of the proposed predictive control scheme for different references and loads is verified through real-time implementation on the basis of dSPACEDS1103.

• 한국식품영양과학회지
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• 제1권1호
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• pp.5-8
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• 1972

Ordinary biological methods of evaluating protein quality are subjected to various sources of error, such as preliminary feeding, body weight of the animals, length of feeding period, endogenous nitrogen metabolism, etc. (1). Wide variations in the reported data may be partly due to this fact. The author postulated that by applying labelled protein these shortcomings may be avoided and that a balance study using nitrogen-15 would give most reliable data, uninfluenced by other factors which are unavoidable in ordinary balance studies using unlabelled nitrogen (2). However, the most important prerequisite for testing this assumption is to obtain labelled protein. As it has been known long since that chlorella contains a large amount of protein and can be easily cultured in quantity (3, 4), it was thought that labelled protein might be obtained by adding $N^{15}$ into the culture media. In this study it has been tried to find out, therefore, whether it is possible to obtain labelled protein by incorporating $KN^{15}\;O_3$ into the culture fuid and at what stage of growth the incorporation of the label into chlorella occurs.

• 한국정밀공학회지
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• 제22권8호
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• pp.192-198
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• 2005

In this paper, we propose a new training system for the improvement of equilibrium sense using unstable platform. The equilibrium sense, which provides orientation with respect to gravity, is important to integrate the vision, somatosensory and vestibular function to maintain the equilibrium sense of the human body. In order to improve the equilibrium sense, we developed the software program such as a block game, pingpong game using Visual C++. These training system for the equilibrium sense consists of unstable platform, computer interface and software program. The unstable platform was a simple structure of elliptical-type which included tilt sensor, wireless RF module and the device of power supply. To evaluate the effect of balance training, we measured and evaluated the parameters as the moving time to the target, duration to maintain cursor in the target of screen and the error between sine curve and acquired data. As a results, the moving time to the target and duration to maintain cursor in the target was improved through the repeating training of equilibrium sense. It was concluded that this system was reliable in the evaluation of equilibrium sense. This system might be applied to clinical use as an effective balance training system.

• Journal of Applied Biological Chemistry
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• 제43권1호
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• pp.18-24
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• 2000

A one-dimensional transport of displacing monovalent ion, $A^+$, and a trivalent ion being displaced, $B^{3+}^ in a porous exchange system such as soil was approximated using the Crank-Nicolson implicit finite difference technique and the Thomas algorithm in tandem. The variations in the concentration profile were investigated by varying the ion-exchange equilibrium constant (k) of ion-exchange reactions, the influent concentrations, and the cation exchange capacity (CEC) of the exchanger, under constant flux condition of pore water and dispersion coefficient. A higher value of k resulted in a greater removal of the native ion, behind the sharper advancing front of displacing ion, while the magnitude of the penetration distance of $A^+$ was not great. As the CEC increased, the equivalent fraction of $B^{3+}^ initially in the soil was greater, thus indicating that a higher CEC adsorbed trivalent cations preferentially over monovalent ions. Mass balance error from simulation results was less than 1%, indicating this model accounted for instantaneous charge balance fairly well.

• Physical Therapy Rehabilitation Science
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• 제10권1호
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• pp.69-75
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• 2021

Objective: This study was aimed at investigating the effects of lumbar stabilization exercise according to correct verbal instructions in pain and muscle strengthening of the low back pain patients. Design: A randomized controlled trial. Methods: Twenty subjects with low back pain were selected. They were randomly assigned to one of two groups (10 in each group): namely the lumbar stabilization exercise and lumbar stabilization exercise according to the correct verbal instructions group. The lumbar stabilization exercise group performed lumbar stabilization exercises for 6 weeks (5 times a week). The lumbar stabilization exercise according to correct verbal instructions group performed lumbar stabilization exercise according to correct verbal instructions for 6 weeks (5 times a week). We measured pain, muscle power, proprioception, and body balance before and after exercise by using visual analog scale (VAS), digital handheld dynanometer, Joint repositioning error, time up and go test respectively. Results: We found statistically significant differences in pain, muscle power, proprioception, and body balance in lumbar stabilization exercise and lumbar stabilization exercise according to correct verbal instructions group, before and after (p<0.05). Conclusions: We confirmed the effect of lumbar stabilization exercise according to correct verbal instructions. Thus we thought these results could be used as basic data and reference for low back pain. But we need more study effect of correct verbal instructions on other exercises.

• PNF and Movement
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• 제20권3호
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• pp.399-408
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• 2022

Purpose: This study investigated the differences in winged scapula between the symptomatic side and asymptomatic side, the reliability of the winged scapula test, and the correlation between winged scapula and the stability of the scapula in patients with subacromial impingement syndrome. Methods: Twenty-four patients with unilateral subacromial impingement syndrome participated in this study. Winged scapula was compared between the symptomatic and asymptomatic sides using a scapulometer. The reliability of the scapulometer was assessed by calculating the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal clinically important difference (MCID). The correlation between winged scapula and the results of the upper quarter Y-balance test were also obtained. Conclusion: Winged scapula was significantly greater on the symptomatic side compared with the asymptomatic side (p < 0.05). High to excellent ICCs were obtained for the winged scapula test, and SEM and MCID values were obtained for winged scapula (SEM: 0.2-0.3 cm, MCID: 0.6-0.8 cm); however, winged scapula and the results of the upper quarter Y-balance test were not correlated. Conclusion: The scapulometer is useful for measuring winged scapula in patients with subacromial impingement syndrome.

• 대한교통학회지
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• 제26권2호
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• pp.147-156
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• 2008

교통수요분석시 기종점(O/D) 존의 집계수준과 네트워크의 구축수준이 어느 정도 균형(balance)이 이루어져야 하는데, 실제로는 불균형을 이루고 있는 경우가 있어 실제교통량과 예측교통량간의 차이가 발생하는 원인중의 하나로 간주되고 있다. 본 연구에서는 소규모 네트워크를 대상으로 O/D존 수와 네트워크의 구축수준에 따른 통행수요의 변화를 살펴보고, 이를 통하여 O/D존수와 네트워크간의 균형(balance)문제를 검토해 보았다. 분석방법은 Sioux-Falls network를 대상으로 네트워크를 추가/삭제시키고, 그에 따라 O/D존의 수도 일정비율로 변화시켜 분석하였다. 분석된 자료를 검증척도인 RMSE와 F-검정을 통해 비교 분석한 결과, 네트워크 증가시에는 예상과는 달리, 네트워크 상세화에 대하여 O/D존수의 증가/감소가 민감하게 반응하지 않는 것으로 나타났으나, 네트워크 집계(삭제)시에는 O/D존의 수도 역시 함께 감소시켜야 오차를 줄일 수 있는 것으로 나타나 이들 간에는 밀접한 관계가 있음을 보여주었다. 이는 교통수요분석을 위하여 네트워크를 구축할 때, O/D존수(존의 크기)도 함께 고려해야 하며, 이들간에 균형(balance)이 이루어지도록 설계해야 함을 의미한다.