• The Journal of Korean Physical Therapy
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• 제30권1호
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• pp.1-7
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• 2018

Objective: This study aimed to determine the efficacy of flexible pole training combined with lumbar stabilization in improving trunk muscle activities and to investigate the difference according to posture in young adults. Methods: Twenty-five participants were enrolled in this study. The subjects were randomly allocated into either the flexible pole group or the rigid pole group. Participants performed lumbar stabilization exercises on quadruped and curl-up, with the flexible pole or rigid pole. Electromyography was used to assess the percent maximal voluntary isometric contracion (%MVIC) of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spine (ES) muscles. All participants completed one 30-minute session per day, 3 days per week, for 6 weeks. The evaluation was performed before and 6 weeks after the training, and follow-up. The data were analyzed using independent t-test and two-way repeated measure analysis of variance to determine the statistical significance. Results: The flexible pole in curl-up showed significant differences in EO and IO muscle activities compared with the rigid pole. The flexible pole in quadruped showed significant differences in IO and ES muscle activities compared with the rigid pole. The RA, EO, IO, and ES muscle activities of both groups were significantly higher after 6 weeks training. Conclusion: The flexible pole in curl-up and quadruped showed an improvement in trunk muscle activation. The flexible pole combined with lumbar stabilization will be useful as an exercise tool to improve activity of trunk muscles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.433-435
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• 2003

As the nation's standard of living rises lately, the common interest in the environmental issue is raised and the environmental design of a transmission line is needed. When the environmental design is needed, KEPCO used a steel pole instead of a rectangular tower. A steel pole has many advantages such as simplification of a tower and less damage to the forest according to less demand of site. But the weak withstand weight of a mono type steel pole is a problem. This paper introduces an H type steel pole which improves its withstand weight, reduces a diameter of a pole from 2.6m to 1.3m and decreases joining points according to the increase of unit length of a pole from 6m to 9m.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제50권6호
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• pp.273-281
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• 2001

In order to overcome the demerit and to improve the operation characteristics of Moving Coil type Linear Oscillatory Actuator(MC-LOA) with single-pole permanent magnet, this paper presents two models having the balanced magnetic circuit by multi-pole permanent magnet. They are short coil type with two-pole single-sided and two-ple double-sided permanent magnet. The characteristics between single-pole and multi-pole permanent magnet type MC-LOA are compared. As a result, multi-pole type MC-LOA has more merits than single-pole type about operation characteristics improvement and machine volume. The characteristics analysis is performed by their dynamic analysis composed of kinetic and electric equations and Finite Element Method(FEM). The propriety of multi-pole type MC-LOA model is verified with analysis results.

• 전력전자학회논문지
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• 제25권6호
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• pp.459-468
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• 2020

The pole interaction of the line-commutated converter high-voltage direct current (HVDC) is analyzed, and a practical solution that uses a surge arrester is proposed. Jeju HVDC No. 2 is a double-monopole HVDC link that has a rated power capacity of 2 × 200 MW and was commissioned in 2012. During normal operation, Jeju HVDC No. 2 is operated in the bipolar mode to minimize the loss caused by the dedicated metallic return. However, when one pole of the inverter valve is bypassed, a commutation failure can occur in the other pole. This phenomenon is called pole interaction in this work. This pole interaction interrupts the HVDC power transfer for almost 2 s and may affect the stability of the power system. This research proposes the installation of a surge arrester at the inverter neutral, which can be an effective and practical solution for pole interaction. The HVDC system is analyzed, and the residual voltage of the surge arrester is determined. Detailed simulation using PSCAD/EMTDC demonstrates that the proposed method eliminates the pole interaction of the bipolar-operated HVDC.

• 조명전기설비학회논문지
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• 제23권10호
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• pp.128-133
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• 2009

본 논문에서는 전류보조전극 및 전위보조전극의 접지저항 측정위치에 따른 접지저항 측정결과를 비교 분석하였다. 국내의 경우 접지전극의 대각선 길이의 6.5배 이상에서 접지저항을 측정하고 있으나 도심지역에서는 이와 같은 방법은 한계를 나타내고 있다. 이를 해결하기 위해 본 논문에서는 접지저항 측정시 접지전극, 전류보조전극과 전위 보조전극간의 거리, 각도를 변경하여 접지저항을 측정하였다. 측정결과 접지전극과 전류보조전극간의 거리를 50[m] 이상, 전위보조전극을 30[m] 이상 이격을 하고 전류보조전극과 전위보조전극을 45도 이상 각도를 유지할 경우 안정적인 접지저항이 측정되었다.

• International Journal of Control, Automation, and Systems
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• 제6권6호
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• pp.939-947
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• 2008

The paper proposes a new formulation of the output feedback pole assignment problem. In this formulation, a unified approach is presented for solving the pole assignment problem with various additional objectives. These objectives include optimizing a variety of performance indices, and imposing constraints on the output feedback matrix structure, e.g. decentralized structure. Conditions for the existence of the output feedback are discussed. However, the thrust of the paper is on the development of a convergent pole assignment algorithm. It is shown that when exact pole assignment is not possible, the method can be used to place the poles close to the desired locations. Examples are provided to illustrate the method.

• Journal of Mechanical Science and Technology
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• 제14권6호
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• pp.590-596
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• 2000

Cause of excessive vibration with twice the rotational speed of a two-pole generator rotor for the fossil power plants was investigated. The two-pole generator rotor, treated as a typically asymmetric rotor in vibration analysis, produces asynchronous vibration with twice the rotational speed, sub-harmonic critical speeds, and potentially unstable operating zones due to its own inertia and/or stiffness asymmetry. This paper introduces a practical balancing procedure, and presents the results of the investigation on sources of the excessive vibration based on the experimental vibration data of the asymmetric two-pole rotor in balancing.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.44-46
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• 2008

This paper presented the notch effect of interior permanent magnet motor(IPM) with compound variable number of pole and slot. The selection of proper pole and slot which makes characteristic and efficiency of motor is very important on motor design. The motor which has 6pole and 9slot is at base. This paper is choose the 4pole 6slot motor which has 2:3 ratio then analyzed the characteristic.

• 한국안전학회지
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• 제26권6호
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• pp.7-12
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• 2011

In recent years, environmental concerns have been raised on the use of poorly biodegradable fluids in electrical apparatus in regions where spills from leaks and equipment failure could contaminate the surroundings. The newly invented vegetable insulating oil is highly biodegradable and have negligible impact on the environment, human health and the ecosystem. For development of the environmental-friendly pole transformer using vegetable insulating oil, the dielectric constructions of the pole transformer were discussed in this paper. Depending on the dielectric constructions, the AC breakdown characteristics of the Nomex insulating papers and the vegetable insulating oil were studied by simulated electrode systems. Based on the experimental results, the maximum design stress($E_{max}$) for insulation design of the environmental-friendly pole transformer were suggested.

• 제어로봇시스템학회논문지
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• 제13권6호
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• pp.574-580
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• 2007

This paper deals with LQR controller design method tor system having complex poles. The proposed method is capable of systematically calculating weighting matrices based on the pole's moving-range and the relational equation between closed-loop pole(s) and weighting matrices. The method moves complex poles to complex poles or two distinct real poles. This will provide much-needed functionality to apply LQR controller. The example shows the feasibility of the proposed method.