• International Journal of Automotive Technology
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• 제7권1호
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• pp.25-34
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• 2006

For decades, simulation technique has been well validated in areas such as computer and communication systems. Recently, the technique has been much used in the area of transportation and traffic forecasting. Several methods have been proposed for investigating complex traffic flows. However, the dynamics of vehicles and diversities of driver characteristics have never been considered sufficiently in these methods, although they are considered important factors in traffic flow analysis. In this paper, we propose a traffic simulation tool called Multi-Agent for Traffic Simulation with Vehicle Dynamics Model (MATDYMO). Road transport consultants, traffic engineers and urban traffic control center managers are expected to use MATDYMO to efficiently simulate traffic flow. MATDYMO has four sub systems: the road management system, the vehicle motion control system, the driver management system, and the integration control system. The road management system simulates traffic flow for various traffic environments (e.g., multi-lane roads, nodes, virtual lanes, and signals); the vehicle motion control system constructs the vehicle agent by using various vehicle dynamic models; the driver management system constructs the driver agent capable of having different driving styles; and lastly, the integrated control system regulates the MATDYMO as a whole and observes the agents running in the system. The vehicle motion control system and driver management system are described in the companion paper. An interrupted and uninterrupted flow model were simulated, and the simulation results were verified by comparing them with the results from a commercial software, TRANSYT-7F. The simulation result of the uninterrupted flow model showed that the driver agent displayed human-like behavior ranging from slow and careful driving to fast and aggressive driving. The simulation of the interrupted flow model was implemented as two cases. The first case analyzed traffic flow as the traffic signals changed at different intervals and as the turning traffic volume changed. Second case analyzed the traffic flow as the traffic signals changed at different intervals and as the road length changed. The simulation results of the interrupted flow model showed that the close relationship between traffic state change and traffic signal interval.

• 한국염색가공학회지
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• 제8권5호
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• pp.7-16
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• 1996

The air-flow dyeing machine is a new type of dyeing machine. Which is an energy saving type to be able to dye the fabrics with the lowest liquor ratio and in shorter time. This machine is operated with an aerodynamic system rather than a hyd raulic system for traditional jet or overflow dyeing. An air-flow dyeing machine(Green-flow) by the use of aerodynamic technology was developed and compared with the Luft-roto machine made by Thies Company, Germany, in this study. Three samples were dyed with both machines under the same dyeing conditions and color fastness, dyeing levelness, drapability, and mechanical properties of these samples were compared. The results were as follows; Both machines have almost the same dyeability. The dyeability was good at liquor ratio of 1: 3.5 and the speed of 450yds/min. The order for drapability was Crepe de Chine > Cool Peach > Charmeuse. Except for the color fastness of sublimation being below class 4, most color fastness of samples dyed with Green-flow m/c were above class 4. The maximum speed was 510yds/min. for Crepe de Chine and the standard deviation of K/S value was lower for Charmeuse and Cool Peach when employed on the "Green-flow" machine and lower for Crepe de Chine when employed on the Luft-roto machine. Comparing with dyeing of the Green-flow machine and that of the Luft-roto machine, the RT of the Charmeuse was found to be higher with the Green-flow machine and thus the sample had an improved wrinkle recovery. LT and WT of Cool Peach were higher, and shear properties(G, 2HG, 2HGS) of Crepe de Chine were higher, both turning out as suitable for clothing. clothing.

• 전기학회논문지
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• 제65권8호
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• pp.1466-1477
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• 2016

This paper analyzes the electrical characteristic such as the impedance(Z), inductance(L), and cable resistance($R_p$) according to the change of cable length in order to move the electrical sorting device for distinguishing between AF non-insulated track circuits from the center of railway to outside railway. The simulation is performed to check the voltage difference between the voltage of sender and the voltage of receiver and determine the possibility of the voltage restoration availability in the frequency filter band through the capacitor compensation. It was applied to the results of the simulation to the sorting devices installed in the actual field. It is proved the availability by checking the measured voltage characteristic according to the capacitor compensating change of $10{\mu}F$ and $16{\mu}F$ before, and after the length of cable is increased with 6 meters. Through this, the prevention of breakdown and damage to facilities and the prevention the safety-related accidents of line workers from the train are expected according to moving the sorting devices of AR non-insulated track circuits to outside railway.

• 한국전산구조공학회논문집
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• 제32권5호
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• pp.297-304
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• 2019

본 논문에서는 접착영역 모델을 이용하여 2상 리튬이온 충전 시 실리콘 음극 전극의 균열진전 해석을 수행하였다. 리튬화 실리콘은 결정질 실리콘에 비해 부피가 약 3배 이상 크므로 리튬이온 충전 시 외각의 리튬화 실리콘에 매우 큰 압축력이 작용하여 압축항복이 발생한다. 리튬이온 충전 시 외각의 리튬화 실리콘은 압축항복 후에 내부의 결정질 실리콘이 리튬화 실리콘으로 상 변이하면서 발생하는 부피 팽창으로 인해 인장력이 작용한다. 이러한 인장력으로 인해 발생하는 균열진전을 접착영역 모델을 이용하여 모사하였다. 사용한 접착영역 모델은 PPR 포텐셜 기반 접착영역 모델로 하나의 포텐셜을 사용하여 복합모드에 대해서도 에너지 소산에 일관성을 지니고 있다. 유한요소 수치해석 모델로 2상 리튬이온 충전 시 모서리 균열진전을 모사한 결과가 실제 실험결과와 일치함을 확인하였고, 균열 팁에서의 최대 인장응력의 각도를 분석하여 실제 실험처럼 균열진전 방향이 회전할 것을 예측할 수 있었다.

• 한국추진공학회지
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• 제23권5호
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• pp.27-35
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• 2019

스텔스 기술은 레이더 및 적외선 시커와 같은 탐지기로부터의 탐지를 피하는 기술이다. 특히 IR 미사일은 항공기 자체의 열을 감지하기 때문에 적외선 신호에 의한 탐지는 더욱 위협적이며 적외선 스텔스 기술은 항공기 및 UCAV(Unmanned Combat Aerial Vehicle)의 생존을 보장하는데 필수적이다. 본 연구에서는 UCAV 노즐 설계에 따른 공력 및 적외선 스텔스 성능 분석이 수행되었다. 수치해석 결과에 따르면 Double S형 노즐은 엔진의 고온부를 차폐할 수 있기 때문에 적외선 신호를 줄이는 데 효과적이다. 또한, Double S형 노즐에서 회전부 위치가 뒤쪽에 위치할수록 적외선 신호가 감소함을 확인하였다.

• 대한조선학회논문집
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• 제32권4호
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• pp.19-26
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• 1995

선박의 조종성능 평가는 유체역학적으로 매우 복잡한 문제로, 정화한 조종성능 평가를 위해서는 구속모형시험에 의한 유체력의 계측과 수학모델에 의한 수치시뮬레이션, 또는 자유항주시험 등이 필수적이다. 한편 최근 IMO의 "조종성 기준"이 발효되고 나서 각 조선현장에서는 이 기준에 부합되는 우수한 조종성능을 갖춘 선박을 설계초기 단계에서부터 계획할 필요성을 느끼게 되었다. 그러나, 초기설계단계에는 아직 선도가 정해지지 않아, 모형선을 만들수 없고, 따라서 선박의 주요목(예를 들어 L, B, d, $C_b$, Trim $\cdot\;cdot\;cdot$) 및 프로펠러 제원, 타(舵)형상과 같은 극히 제한된 자료를 입력(入力)으로 하여 조종성능을 어느정도 평가할 수 있어야 한다. 본 논문은 이러한 관점에서, 종래의 각종 구속모형시험 결과를 종합하고, 제안된 경험식등을 이용하여 선박의 조종성능을 추정하는 전산 프로그램을 개발하였다.

• 대한치과교정학회지
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• 제49권4호
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• pp.254-264
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• 2019

Objective: To evaluate the short-term changes in masticatory muscle activity and mandibular movement patterns after orthognathic surgery in skeletal Class III patients with facial asymmetry. Methods: Twenty-seven skeletal Class III adult patients were divided into two groups based on the degree of facial asymmetry: the experimental group (n = 17 [11 male and 6 female]; menton deviation ${\geq}4mm$) and control group (n = 10 [4 male and 6 female]; menton deviation < 1.6 mm). Cephalography, electromyography (EMG) for the anterior temporalis (TA) and masseter muscles (MM), and mandibular movement (range of motion [ROM] and average chewing pattern [ACP]) were evaluated before (T0) and 7 to 8 months (T1) after the surgery. Results: There were no significant postoperative changes in the EMG potentials of the TA and MM in both groups, except in the anterior cotton roll biting test, in which the masticatory muscle activity had changed into an MM-dominant pattern postoperatively in both groups. In the experimental group, the amount of maximum opening, protrusion, and lateral excursion to the non-deviated side were significantly decreased. The turning point tended to be shorter and significantly moved medially during chewing in the non-deviated side in the experimental group. Conclusions: In skeletal Class III patients with facial asymmetry, the EMG activity characteristics recovered to presurgical levels within 7 to 8 months after the surgery. Correction of the asymmetry caused limitation in jaw movement in terms of both ROM and ACP on the non-deviated side.

• The Journal of Korean Physical Therapy
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• 제31권2호
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• pp.67-75
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• 2019

Purpose: Patients with brain damage suffer from limitations in performing the activities of daily living (ADL) because of their motor function and visual perception impairment. The aim of this study was to help improve the motor function and visual perception ability of patients with brain damage by providing them with virtual reality-based contents. The usability results of the patients and specialists group were also evaluated. Methods: The ADL contents consisted of living room, kitchen, veranda, and convenience store, similar to a real home environment, and these were organized by a rehabilitation specialist (e.g., neurologist, physiotherapist, and occupational therapist). The contents consisted of tasks, such as turning on the living room lights, organizing the drawers, organizing the kitchen, watering the plants on the veranda, and buying products at convenience stores. To evaluate the usability of the virtual reality-based visual cognitive rehabilitation service, general elderly subjects (n=11), stroke patients (n=7), stroke patients with visual impairment (n=4), and rehabilitation specialists (n=11) were selected. The questionnaires were distributed to the subjects who were using the service, and the subjective satisfaction of individual users was obtained as data. The data were analyzed using SPSS 21.0 software. The general characteristics of the users and the evaluation scores of the experts were analyzed using descriptive statistics. Results: The usability test result of this study showed that the mean value of the questionnaire related to content understanding and difficulty was high, between 4-5 points. Conclusion: The virtual reality rehabilitation service of this study is an efficient service that can improve the function, interest, and motivation of stroke patients.

• Journal of Animal Science and Technology
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• 제63권2호
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• pp.440-452
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• 2021

The purpose of this study was to determine if an 8-week therapeutic riding (TR) program was effective in improving the walking ability of students with intellectual disabilities. Thirteen students diagnosed with intellectual disabilities participated in the TR program. TR sessions were conducted twice a week (30 min per session), with a total of 16 rides taking place over an 8-week period. A gait measurement analyzer was used to measure progress based on a turn test (6-m walking and turning test), walk test (10-m walking), and timed up and go (TUG) test. Measurements were made three times: before horse-riding (P0), after 4 weeks (8 rides) of horse-riding (P1), and after 8 weeks (16 rides) of horse-riding (P2). Data analysis was conducted using SPSS software (ver. 22.0). Descriptive statistics were generated on the general characteristics of the subjects, and the Kolmogorov-Smirnov test was used to verify the normality of the data. Because of the lack of normality, the data were analyzed using a nonparametric method and the significance level was set to 0.05. Measurements of the duration of the forward gait cycle (s) in the turn test and the forward gait speed (m/s) in the walk test indicated improved walking ability after the TR program (p < 0.001); the stride length (% height) also increased significantly (p < 0.05). The walk test revealed a significant effect of the program on the duration of the forward gait cycle (p < 0.05), while there were significant improvements on the left and right of the elaborated strides (p < 0.001). No significant improvement in TUG test performance was observed after the TR program. In this study, an 8-week TR program had positive results on gait. Therefore, further research is merited, where TR programs are likely to improve the walking ability of individuals with intellectual disabilities.

• Geomechanics and Engineering
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• 제28권5호
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• pp.531-546
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• 2022

Ground displacements caused by the construction of overlapping twin shield tunnels with small turning radius are complex, especially under special geological conditions of construction. To investigate the ground displacements caused due to shield machines in the unique calcareous sand layers in Israel for the first time and determine the main factors affecting the ground displacements, field monitoring, laboratory geological analysis, theoretical calculations, and parameter studies were adopted. By using rod extensometers, inclinometers, total stations, and automatic segment-displacement monitors, subsurface tunneling-induced displacement, surface settlement, and displacement of the down-track tunnel segments caused by the construction of an up-track tunnel were analyzed. The up-track tunnel and the down-track tunnel pass through different stratum, resulting in different construction parameters and ground displacements. The laws of variation of thrust and torque, soil pressure in the chamber, excavated soil quantity, synchronous grouting pressure, and grout volume of the two tunnels from parallel to fully overlapping orientations were compared. The thrust and torque of the shield in the fine sand are larger than those in the Kurkar layer, and the grouting amount in fine sand is unstable. According to fuzzy statistics and Gaussian curve fitting of the shield tunneling speed, the tunneling speed in the Kurkar stratum is twice that in the fine-sand stratum.