• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.269-274
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• 2013

Fault-tolerant capability, wide speed range and overload capability are required in electric motors used in electric vehicles. In this paper, based on the analysis of the all poles wound and alternate poles wound flux-switching permanent-magnet machines, an optimization method is studied to reduce torque ripple. The method takes account of both flux-leakage and cogging torque. The simulation result shows that the method can reduce the torque ripple effectively. This study lays the foundation for the further application of FSPM in electric vehicles.

• Structural Engineering and Mechanics
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• v.59 no.2
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• pp.243-259
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• 2016

This research develops a finite element code for the transient dynamic analysis of tapered fiber reinforced polymer (FRP) poles with hollow circular cross-section and flexible joints used in power transmission lines. The FRP poles are modeled by tapered beam elements and their flexible joints by a rotational spring. To solve the time equations of transient dynamic analysis, precise time integration method is utilized. In order to verify the utilized formulations, a typical jointed FRP pole under step, triangular and sine pulses is analyzed by the developed finite element code and also ANSYS commercial finite element software for comparison. Thereafter, the effect of joint flexibility on its dynamic behavior is investigated. It is observed that by increasing the joint stiffness, the amplitude of the pole tip deflection history decreases, and the time of occurrence of the maximum deflection is earlier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.2
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• pp.107-113
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• 2008

This paper presents half wavelength partial H-plane filters with multiple attenuation poles using narrow H-plane slot of evanescent waveguide. The narrow H-plane slot operates as an admittance inverter o( the bandpass filter and, simultaneously, generates an attenuation pole at particular frequency. Therefore, proposed filters with attenuation poles are simply implemented without any additional coupling and extra modification of the structure. The number of attenuation poles of the filters equals to that of the H-plane slots. Moreover, proposed filters are compact waveguide filter since ones are embodied by partial H-plane waveguide which has 1/4 cross section of conventional waveguide. The third and fourth-order half wavelength filters having 4 and 5 attenuation poles, respectively, are designed in H-band and their frequency responses are confirmed by simulation and measurement.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.2
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• pp.61-67
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• 2003

This paper describes a development of magnetic tomography system using two poles perpendicular magnetic field. In the system, the relative permeabilities of the object are detected by Hall sensors located along with tube circumference. The signals according to the size and position of the object could be separated in case the relative permeability of the object are over 10. Moreover, the size and location of the object could be determined in real time.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.339-344
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• 1993

An H$_{\infty}$ control system design for a magnetic levitation system is presented. In the control system design, we consider the influence of both disturbances and uncertainties in the model. The main disturbances stem from the position sensors.The uncertainties are divided into electromagnetic and mechanical ones: the former are due to the gain change in the current amplifier, the influence of leakage flux and modelling error in the magnetic circuit and the latter are due to the changes of the mass and the moments of inertia of the vehicle. Therefore, the designed controller is indispensable to guarantee the robustness of this system for both stability and performance. The controller design is based on the standard H$_{\infty}$ optimal control problem. As the novel features in this paper :(1) there are two poles on j.omega.-axis in the control model;(2) an integrator is included in the controller so that equivalently there are three poles on j.omega.-axis in the model. Finally, several experiments and simulations are carried out to verify the high performance and robustness of the designed control system.m.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.634-639
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• 2020

In general, the stability and response characteristics of the system can be improved by changing the pole position because a nonlinear system can be linearized by the product of a 1st and 2nd order system. Therefore, a controller that moves the pole can be designed in various ways. Among the other methods, LQ control ensures the stability of the system. On the other hand, it is difficult to specify the location of the pole arbitrarily because the desired response characteristic is obtained by selecting the weighting matrix by trial and error. This paper evaluated a method of selecting a weighting matrix of LQ control that moves multiple double poles with Jordan blocks to real poles. The relational equation between the double poles and weighting matrices were derived from the characteristic equation of the Hamiltonian system with a diagonal control weighting matrix and a state weighting matrix represented by two variables (ρ_d, ϕ_d). The Moving-Range was obtained under the condition that the state-weighting matrix becomes a positive semi-definite matrix. This paper proposes a method of selecting poles in this range and calculating the weighting matrices by the relational equation. Numerical examples are presented to show the usefulness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.729-733
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• 1988

In this paper, a new procedure for selecting weighting matrices in linear discrete time quadratic optimal control problems (LQ-problem) is proposed. In LQ problems, the quadratic weighting matrices are usually decided on trial and error in order to get a good response. But using the proposed method, the quadratic weights are decided in such a way that all poles of the closed loop system are located in a desired area for good responses as well as for stability and values of the quadratic cost functional are kept less then a specified value. The closed loop systems constructed by this method have merits of LQ problems as well as those of pole assignment problems. Taking into consideration that little is known about the relationship among the quadratic weights, the poles and the values of cost functional, this procedure is also interesting from the theoretical point of view.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.377-382
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• 1987

To obtain a high resolution microwave images, back scattering microwave fields from one, two, four poles on a rotating object is measured. A computation algorithm to reconstruct these poles images from measured data is programed. The program is tested for these poles on a rotating object for different frequency intervals in the X-Band. The more frequency data yield the reduction of side lobe level. The reconstructed image for the two pole objects having the diameter of 1cm and separated by 1 lamda, 2 lamda (lamda-3.75 cm) from the measured data is shown. And, the image of two objects having the different reflectivity coefficient from the measured data is also shown and it assumes that this reconstructing algorithm from the measured angular spectrum provides quite accurate images.

• Nutrition Research and Practice
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• v.9 no.3
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• pp.319-327
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• 2015

BACKGROUND/OBJECTIVES: In nutritional epidemiology, collecting self-reported respondent height and weight is a simpler procedure of data collection than taking measurements. The aim of this study was to compare self-reported and measured height and weight and to evaluate the possibility of using self-reported estimates in the assessment of nutritional status of elderly Poles aged 65 + years. SUBJECTS/METHODS: The research was carried out in elderly Poles aged 65 + years. Respondents were chosen using a quota sampling. The total sample numbered 394 participants and the sub-sample involved 102 participants. Self-reported weight (non-corrected self-reported weight; non-cSrW) and height estimates (non-corrected self-reported height; non-cSrH) were collected. The measurements of weight (measured weight; mW) and height (measured height; mH) were taken. Using multiple regression equations, the corrected self-reported weight (cSrW) and height (cSrH) estimates were calculated. RESULTS: Non-cSrH was higher than mH in men on average by 2.4 cm and in women on average by 2.3 cm. In comparison to mW, non-cSrW was higher in men on average by 0.7 kg, while in women no significant difference was found (mean difference of 0.4 kg). In comparison to mBMI, non-cSrBMI was lower on average by $0.6kg/m^2$ in men and $0.7kg/m^2$ in women. No differences were observed in overweight and obesity incidence when determined by mBMI (68% and 19%, respectively), non-cSrBMI (62% and 14%, respectively), cSrBMI (70% and 22%, respectively) and pcSrBMI (67% and 18%, respectively). CONCLUSIONS: Since the results showed that the estimated self-reported heights, weights and BMI were accurate, the assessment of overweight and obesity incidence was accurate as well. The use of self-reported height and weight in the nutritional status assessment of elderly Poles on a population level is therefore recommended. On an individual level, the use of regression equations is recommended to correct self-reported height, particularly in women.

• Korean Journal of Ornithology
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• v.25 no.2
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• pp.112-116
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• 2018

Electrocution is one of the key components affecting the mortality of birds. Various electrocution-decreasing methods refer to two directions: safe perching with insulation versus perching restriction. In Yesan County, we have reintroduced 30 oriental storks (Ciconia boyciana) since 2015. Two female storks died due to electrocution while perching in a utility pole in 2016. To reduce such electrocution mortality in storks, a branch of Korea Electric Power Corporation partly installed insulators in 630 utility poles located in the major habitats of Yesan in 2016-2017. Simultaneously, we conducted an experiment to reduce the perching events using 8 captive storks and the two types of common utility poles along with/without the installation of bird-spikes and/or wires in Mar-Jun of 2017. Our results indicated the installation of additional wires alone exhibited a lack of reduction in perching, while those of bird-spikes or both significantly decreased their perching frequencies. Therefore, the present study highlights the installation of bird spikes on top of utility poles may elicit a better effect so that storks avoid perching in utility poles, presumably resulting in lowering potential electrocution in the wild.