• Journal of international Conference on Electrical Machines and Systems
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• 제2권1호
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• pp.111-119
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• 2013

This paper present stabilization control of fixed speed wind generator by using variable speed permanent magnet wind generator in a wind farm connected with multi-machine power system. A novel direct-current based d-q vector control technique of back to back converter integrated with Fuzzy Logic Controller for optimal control configuration is proposed, in which both active and reactive powers delivered to a power grid system are controlled effectively. Simulation analyses have been performed using PSCAD/EMTDC. Simulation results show that the proposed control scheme is very effective to enhance the voltage stability of the wind farm during fault condition.

• 한국철도학회논문집
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• 제8권5호
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• pp.490-494
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• 2005

The geometric parameters between wheel and rail change wheel/rail contact geometry characteristics, and this influence dynamic behavior of rolling stock. So, the selections of optimum geometric parameters between wheel and rail is important for planning of railway system. In this study, we have analyzed the influence of geometric parameters like wheel flange-back distance, gage, and rail inclination on the equivalent conicity relating to dynamic behavior. The analyses show the following results. The widening of wheel flange-back distanc, the decrement of gage increase the equivalent conicity and the increment of rail inclination show the sharp change of the equivalent conicity.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.430-434
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• 2004

The geometric parameters between wheel and rail change wheel/rail contact geometry characteristics, and this influence dynamic behavior of rolling stock. So, the selections of optimum geometric parameters between wheel and rail is important for planning of railway system. In this study, we have analyzed the influence of geometric parameters like wheel flange-back distance, gage, and rail inclination to the equivalent conicity relating dynamic behavior. The analyses show the following results. The widening of wheel flange-back distance increase the equivalent conicity, the widening of gage, rail inclination 1/20 compared with rail inclination 1/40 decrease the equivalent conicity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1064-1066
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• 2004

This paper deals with analysis of a 3-phase high speed machine with diametrically magnetized rotor. The field equations due to magnet and stator windings are established in terms of vector potential and 2-d polar coordinate systems and then, characteristic equation of torque and back emf are derived by using field equations. Finally, this paper predicts open-circuit field, armature reaction field distributions, field distributions on load, torque and back emf distributions from those of equations. Results are compared with predictions from corresponding finite element analyses.

• 한국지구과학회지
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• 제40권5호
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• pp.476-486
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• 2019

This study examines the controlling role of synoptic disturbances on $PM_{10}$ spring variability in the Korean Peninsula by using empirical orthogonal function (EOF) and back trajectory analyses. Three leading EOF modes are identified, and a lead-lag analysis suggests that $PM_{10}$ variabilities be closely related to the synoptic weather systems. The first EOF shows the spatially homogeneous distribution of $PM_{10}$, which is influenced by travelling anticyclonic disturbance with negative precipitation and descending motion. The second and third modes exhibit the dipole structures of $PM_{10}$, being associated with propagating cyclones. Furthermore, the back-trajectory analysis suggests that the transport of pollutants by anomalous winds associated with synoptic disturbances also contribute to the altered $PM_{10}$ concentration. Hence, a substantial synoptic control should be considered in order to fully understand the $PM_{10}$ spatiotemporal variability.

• 대한인간공학회지
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• 제1권2호
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• pp.3-9
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• 1982

This study demonstrates that certain personal and task factors can be modelled to predict slip potential as well as back loadings durings dynamic pushing and pulling tasks. Such tasks are com- mon to many manual material handling jobs in industry and the results of this work will hopefully be of use in improved job design. The objective of this research is to formulate and validate a dynamic biomechanical model of pushing and pulling a cart. For pushing and pulling tasks, the model can : (1) estimate foot forces for given hand forces, and (2) estimate tors muscle and vertabral column loadings. In order to formulate and validate the model, experiments involving pushing and pulling of a cart were performed. These experiments produced data of the following type : (1) dynamic forces on the feet, (2) hand forces required to move the cart, (3) body motions as functions of various cart motion and (4) back muscle actions. The model was validated using three different methods; precision was tested using correlation between predicted and measured results, accuracy using standard error between of predicted and measured results, and intuitive comparison of predicted results using sensitivity analyses.

• 한국의학물리학회지:의학물리
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• 제26권2호
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• pp.72-78
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• 2015

유기용제는 현기증, 행동장애, 주의산만, 말초신경증과 같은 신경 독성을 일으키는 물질로 잘 알려져 있다. 그러나, 이러한 신경 독성물질인 유기 용제에 노출된 근로자들이 작업 기억 기능을 수행할 때 인지 부하에 어떻게 영향을 받는지에 관해서 많이 연구가 되어오지 않았다. 따라서, 본 연구에서는 기능적인 자기공명영상을 이용하여 만성적으로 유기용제에 노출된 근로자들이 인지 부하에 따른 작업 기억 기능을 수행할 때 보여지는 신경 변화의 관계를 살펴보았다. 29명의 유기용제에 노출된 근로자들을 대상으로 언어적 작업 기억 기능(1-back and 2-back)을 수행시켰으며 낮은 인지 부하와 높은 인지 부하의 작업 기억 기능을 수행할 때, 인지 부하의 차이에 따라 활성화 되는 뇌 영역의 차이를 구하였다. 1-back의 반응속도가 증가함에 따라 좌측 하위 두정 피질에서의 뇌 활성화가 점점 증가하는 관계를 보였는데, 이러한 증가되는 양상이 더 높은 인지 부하인 2-back에서는 보여지지 않았다. 이를 통해, 인지 부하가 많이 걸릴수록 활성화 되는 뇌 영역이 많아지며, 유기용제에 노출된 근로자들은 어느 정도 낮은 인지 부하가 걸렸을 때는 그만큼의 뇌 활성화가 증가되는데, 높은 인지 부하가 걸리게 되면 더 이상 뇌 활성화가 증가되지 않고 한계에 다다르는 것을 알 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.336-339
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• 2006

In this paper, the preliminary transfer orbit analysis results for the COMS mission were presented. As the first step of transfer orbit analysis, the preliminary analyses of LAE burn strategy, geometrical visibility, and launch window were performed. For the analysis process, all launcher nominates were divided into three groups according to the declination of LAE thrust angle. So, the three launch cases were assigned as the representative launcher of each group, respectively. They are Ariane-5, Atlas summer and winter launch cases. And all analyses were performed at the representative launcher of each group. One nominal and three back-up plans were considered for the establishment of LAE burn strategy. And for geometrical visibility analysis, four TT&C ground stations were considered. Finally, the preliminary launch window analysis was performed about the duration of one year from the first day of September 2008. The analysis results show that the all launch cases comply with the transfer orbit operation requirements.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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• pp.171-177
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• 1995

Fracture mechanics does work for concrete, provided that one uses a proper, nonlinear form of fracture mechanics in which a finite nonlinear zone at fracture front is being considered. The fracture process zone is a region ahead of a traction-free crack, and the development of model of fracture process zone is most important to describe fracture phenomena in concrete. This paper is about fracture behavior of concrete cylinder under lateral pressure. Concrete cylinders were made of high strength normal connote, steel fiber reinforced concrete and steel fiber reinforced polymer-impregnated concrete and concrete and the fracture behavior such as cracking propagation and ultimate load are observed. The fracture process zone is modelled by a Dugdale-Barenblatt type model with linear tension-softening curve and are implemented to the boundary element technique for the fracture analyses of the cylinders. The experimental results are compared with analysis results and tension-softening curves for the steel fiber reinforced concrete and steel fiber reinforced polymer-impregnated concrete are obtained by back analyses.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 사면안정 설계 및 시공 특별강연회
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• pp.19-30
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• 2001

This paper represents a case study to determine optimal rock properties and to analyse the safety of slopes excavated in faulted and severly weathered ground. The study site consists of two slopes with a length of 240m and a height of 30m in contact with a tunnel. Significant efforts have been exerted for determining the proper strength parameters such as cohesion and internal friction of rockmass by back analyses as well as laboratory and in-situ tests. Limit equilibrium analyses have also been conducted using these properties.