• 제목/요약/키워드: Symmetrical

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Design Rules of Hybrid Stepping Machine for Free Piston Engine

  • Jeong, Sung-In
    • Journal of Electrical Engineering and Technology
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    • 제12권3호
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    • pp.1219-1226
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    • 2017
  • This paper presents the hybrid stepping machine for linear oscillating generators. The focus of the work is the suggestion of the improved model through the comparison of proposed models ; new flux concentrating PMs mover of the hybrid stepping generator is proposed based on the symmetrical and non-symmetrical stator cores of the surface mounted PMs mover, and non-slanted PMs and slanted PMs of the flux concentrating PMs mover. It is achieved using equivalent magnetic circuit considering leakage elements. Finally, this study suggests new hybrid stepping structure of linear oscillating generator.

HANKEL DETERMINANTS FOR STARLIKE FUNCTIONS WITH RESPECT TO SYMMETRICAL POINTS

  • Nak Eun Cho;Young Jae Sim;Derek K. Thomas
    • 대한수학회보
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    • 제60권2호
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    • pp.389-404
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    • 2023
  • We prove sharp bounds for Hankel determinants for starlike functions f with respect to symmetrical points, i.e., f given by $f(z)=z+{\sum{_{n=2}^{\infty}}}\,{\alpha}_nz^n$ for z ∈ 𝔻 satisfying $$Re{\frac{zf^{\prime}(z)}{f(z)-f(-z)}}>0,\;z{\in}{\mathbb{D}}$$. We also give sharp upper and lower bounds when the coefficients of f are real.

DEGREE OF APPROXIMATION BY KANTOROVICH-CHOQUET QUASI-INTERPOLATION NEURAL NETWORK OPERATORS REVISITED

  • GEORGE A., ANASTASSIOU
    • Journal of Applied and Pure Mathematics
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    • 제4권5_6호
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    • pp.269-286
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    • 2022
  • In this article we exhibit univariate and multivariate quantitative approximation by Kantorovich-Choquet type quasi-interpolation neural network operators with respect to supremum norm. This is done with rates using the first univariate and multivariate moduli of continuity. We approximate continuous and bounded functions on ℝN , N ∈ ℕ. When they are also uniformly continuous we have pointwise and uniform convergences. Our activation functions are induced by the arctangent, algebraic, Gudermannian and generalized symmetrical sigmoid functions.

Sternocleidomastoid and Posterior Cervical Muscle Coordination in Response to Symmetrical and Asymmetrical Jaw Functions in Normal Adults

  • Im, Yeong-Gwan;Kim, Jae-Hyung;Kim, Byung-Gook
    • Journal of Oral Medicine and Pain
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    • 제40권3호
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    • pp.115-123
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    • 2015
  • Purpose: The aim of this study was to elucidate the coordination patterns of the sternocleidomastoid and posterior cervical muscles in response to symmetrical and asymmetrical jaw functions in normal adults. Methods: Twenty-seven healthy volunteers (8 females, 19 males; mean age, $30.4{\pm}2.5$ years) participated in this study. Surface electromyography (EMG) was used to record activities in the masseter, suprahyoid, sternocleidomastoid, and posterior cervical muscles at rest and during maximum tooth clenching, biting of a cotton roll with the anterior teeth, unilateral biting of a cotton roll with the posterior teeth, bilateral biting of cotton rolls with the posterior teeth, and jaw opening while seated. Normalized amplitude, activity indices, and asymmetry indices were compared between the muscles and the jaw tasks. Results: During symmetrical jaw functions (e.g., tooth clenching, biting with the anterior teeth, bilateral biting with the posterior teeth, jaw opening), the sternocleidomastoid and posterior cervical muscles showed elevated EMG amplitudes compared with the resting condition. The co-activation pattern of the sternocleidomastoid muscle was more pronounced than those of the posterior cervical muscles during these tasks. During asymmetrical jaw functions (e.g., unilateral biting with the posterior teeth), the ipsilateral sternocleidomastoid and masseter muscles showed higher contraction activity than did the contralateral muscles, but the contralateral posterior cervical muscles were more active than the ipsilateral muscles. Conclusions: The sternocleidomastoid and posterior cervical muscles were shown to be co-activated and coordinated anteroposteriorly or bilaterally according to symmetrical or asymmetrical jaw function. These results suggest an integrated neural control mechanism for the jaw and neck muscles, and provide further evidence supporting the intimate functional coupling between the trigeminal and cervical neuromuscular systems.

A New Photovoltaic System Architecture of Module-Integrated Converter with a Single-sourced Asymmetric Multilevel Inverter Using a Cost-effective Single-ended Pre-regulator

  • Manoharan, Mohana Sundar;Ahmed, Ashraf;Park, Joung-Hu
    • Journal of Power Electronics
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    • 제17권1호
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    • pp.222-231
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    • 2017
  • In this paper, a new architecture for a cost-effective power conditioning systems (PCS) using a single-sourced asymmetric cascaded H-bridge multilevel inverter (MLI) for photovoltaic (PV) applications is proposed. The asymmetric MLI topology has a reduced number of parts compared to the symmetrical type for the same number of voltage level. However, the modulation index threshold related to the drop in the number of levels of the inverter output is higher than that of the symmetrical MLI. This problem results in a modulation index limitation which is relatively higher than that of the symmetrical MLI. Hence, an extra voltage pre-regulator becomes a necessary component in the PCS under a wide operating bias variation. In addition to pre-stage voltage regulation for the constant MLI dc-links, another auxiliary pre-regulator should provide isolation and voltage balance among the multiple H-bridge cells in the asymmetrical MLI as well as the symmetrical ones. The proposed PCS uses a single-ended DC-DC converter topology with a coupled inductor and charge-pump circuit to satisfy all of the aforementioned requirements. Since the proposed integrated-type voltage pre-regulator circuit uses only a single MOSFET switch and a single magnetic component, the size and cost of the PCS is an optimal trade-off. In addition, the voltage balance between the separate H-bridge cells is automatically maintained by the number of turns in the coupled inductor transformer regardless of the duty cycle, which eliminates the need for an extra voltage regulator for the auxiliary H-bridge in MLIs. The voltage balance is also maintained under the discontinuous conduction mode (DCM). Thus, the PCS is also operational during light load conditions. The proposed architecture can apply the module-integrated converter (MIC) concept to perform distributed MPPT. The proposed architecture is analyzed and verified for a 7-level asymmetric MLI, using simulation results and a hardware implementation.

30대에서 80대까지의 똑바로 누운 자세에서 일어서기 운동형태 (Movement Patterns for Rising from Supine to Erect Stance in the Third through Eighth Decades)

  • 배성수;박상옥;윤창구;권미지
    • The Journal of Korean Physical Therapy
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    • 제8권1호
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    • pp.65-78
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    • 1996
  • This study wan described the movement patterns when rising from supine to erect stance in the third through eighth decades. Two hundred fifty six subjects, ranging in age from 30 year to 89 were filmed while rising from a supine position. Movement patterns were classified using categorical descriptions of the action of the upper and lower extremity, head-trunk region. This study was designed to determine whether within the rising task the movement patterns of different regions of the body vary with age level and sex, to describe time by subjects to perform this task. The incidence of each movement pattern was calculated and graphed wi th respect to age level and sex. Erect standing time was increased by age increasing in beth sex group. The most common form of rising for subject in the third through fifth decades both sex usually involved symmeytrical push with upper extremity, symmetrical squat pattern with lower extremity, partial rotation pattern wi th head-trunk and symmetrical push to push and reach pattern with upper extremity, symmetri cal squat pattern with lower extremity. partial rotation with head-trunk. In the sixth through eighth decades usually involved symmetrical push to push and reach pattern with upper extremity, symmetrical squat pattern with lower extremity, partial rotation pattern with head-trunk in both sex group.

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태양광발전이 연계된 배전계통의 보호기기 오동작에 대한 최적 운용방안에 관한 연구 (A Study on the Optimal Method for Mal-function of Re-closer at the Distribution Feeders Interconnected with PV Systems)

  • 김찬혁;박현석;노대석;신창훈;윤기갑
    • 전기학회논문지
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    • 제58권8호
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    • pp.1512-1518
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    • 2009
  • Recently, new dispersed power sources such as photovoltaics, wind power, fuel cell etc. are energetically interconnected and operated in the distribution systems, as one of the national projects for alternative energy. This paper deals with the optimal countermeasures for the mal-function of protective devices at primary feeder in distribution systems when new power sources like photovoltaic (PV) systems are interconnected, based on the symmetrical components of short circuit studies. When new power sources are considered to be interconnected to distribution systems, bi-directional power flow and interconnection transformer connection of new power sources may cause the operation problems of protective devices (mainly re-closer), since new power sources can change typical characteristics of distribution systems. Therefore, this paper shows an analysis skill of the mal-functional mechanism of protective relay and proposes the optimal solution for the mal-function problem using the symmetrical components of fault analysis. And, this paper also shows the effectiveness of proposed method by the simulation at the field distribution systems.

플라나 마이크로스트립 전송선의 효율적 해석 방법 (An Efficient Analysis Method for Planar Microstrip Transmission Line)

  • 김태원
    • 전자공학회논문지 IE
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    • 제45권2호
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    • pp.13-19
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    • 2008
  • TLM 수치 해석법의 주요한 장점은 가장 복잡한 전송선 구조에 있어서도 해석이 용이하다는 것이다. 본 논문에서는 대칭압축노드를 이용한 TLM법을 마이크로스트립 meander 라인에 성공적으로 적용하였다. 플라나 마이크로스트립 전송선을 모델화하기 위한 대칭압축노드에 대한 상세한 기술이 제시되었고 또한 2종류의 마이크로스트립 meander 라인의 산란 파라메터 $S_{11}$$S_{21}$을 계산하였다. 구해진 결과로부터 TLM 해석법이 복잡한 플라나 마이크로웨이브 전송선 구조를 모델링하는데 유용한 해석법임을 보였다. 제시된 TLM 해석 결과는 고주파 영역에서 마이크로웨이브 집적 회로를 설계하는데 유용하게 사용될 수 있다.