• Title/Summary/Keyword: five weakening

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Field Weakening Control for Five-Phase IPM Motor (Five-Phase IPM Motor의 약계자 제어)

  • Kim Nam-Hun;Kim Min-Huei;Baik Won-Sik;Hwang Don-Hwa;Kim Dong-Hee
    • Proceedings of the KIPE Conference
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    • 2006.06a
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    • pp.95-97
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    • 2006
  • This paper investigates the field weakening operation of a five-phase IPMSM(inner permanent magnet synchronous motor). The five-phase motor can supply sinusoidal voltage and third harmonic voltage because of more freedom of control. This paper present field weakening algorithm and experimental results for five-phase IPMSM which has trapzoidal back-EMF and concentrate winding to prove the validity of the proposed algorithm.

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Field Weakening Operation of a High Torque Density Five Phase Permanent Magnet Motor Drive (고밀도 토크를 가지는 5상 영구자석형 전동기의 약계자 제어)

  • Kim, Nam-Hun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.12 no.4
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    • pp.318-323
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    • 2007
  • This paper investigates the field weakening operation of a five-phase permanent magnet motor. The proposed motor has concentrated windings such that the produced back-EMF is almost trapezoidal and is supplied with the combined sinusoidal plus third harmonic of currents to produce trapezoidal current. Therefore this motor, while generating the same average torque as an equivalent permanent magnet brushless dc motor, overcomes its disadvantages. It is shown that torque producing and flux producing components of current for this motor can be decoupled by using multiple reference frame transformation. Therefore, Vector control is easily applicable to the motor. This motor has benefits such as high torque density of a BLDC motor below the rated speed and controllability of PMSM above the rated speed and during the field weakening region and simulation and experimental results are provided to prove the validity of the superior performance of this drive.

Influence of Taking Medicine for a Period of Time on the Liver Function and Improvement of the Developmental Disordered Children (한약 장기복용이 발달장애아동의 간기능과 건강증진에 미치는 영향)

  • Park, Jae-Hyung;Park, Jae-Hyun;Yoon, Young-Joo;Jeong, Seul-Ki;Lee, Hyun-Jung;Lim, Ja-Sung;Bahn, Geon-Ho;Moon, Jin-Soo;Paeck, Eun-Kyung
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.20 no.2
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    • pp.494-497
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    • 2006
  • A child with five delay, five ankylosis, five weakening needs to take herbal medicine for a long term. So safety, efficacy inspection for the long term usage of herbal medicine and mixed dose is needed because other medication or functional health foods, etc could be taken during this process. Operated liver function test before and after dosing herbal medicine to one hundred and sixty children who aided private oriental medicine located in Seoul, and measured the efficacy by comparing sleeping hours, morbidity, stamina, sanguineness, personality, digestion with the state before taking herbal medicine based on questionnaire done by the parents. Every children were under the limits, and there were no differences between boys and girls, and no notable differences according to family histories. There were positive results in efficacy inspection ordered as improvement in personality, stamina, sanguineness, decrease in morbidity, increase in appetite, digestion. No signs of disorder in liver function has been found during the dose of herbal medicine or simultaneous medicine, and shown promotion of health.

Comparative Analysis of Magnetic Slot Wedges Design for Increasing Performance of Railway Traction Motor

  • Liu, Huai-Cong;Cho, Sooyoung;Hong, Hyun-Seok;Joo, Kyoung-Jin;Ham, Sang-Hwan;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.12 no.6
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    • pp.2411-2418
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    • 2017
  • This study focuses on the effects of using open stator slots in an interior permanent magnet traction motor with a magnetic slot wedge design in order to increase the power density at its base speed. In addition, such a configuration reduces the torque ripple under field-weakening conditions. Five different wedge models were selected, each of which was evaluated using a finite element analysis (FEA). Based on the initial model, we designed magnetic slot wedges for maximum back-EMF and minimum cogging torque. In addition, the d-q axis inductance was slightly altered due to the magnetic slot wedges. Finally, we analyzed the performance of a traction machine under field weakening control. Moreover, we have outlined the requirements for an ideal magnetic slot wedge design.

Association between business switch or liquidation, and the demographics of Small and Medium Enterprises in South Korea

  • Jeong, Dong-Bin
    • The Journal of Industrial Distribution & Business
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    • v.9 no.9
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    • pp.25-33
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    • 2018
  • Purpose - In this study, we consider and examine relationships between reasons for business switch or liquidation (BSL), and the demographics of small and medium enterprises (SMEs) in South Korea. The related five variables are occupations, administrative districts, age of employer, firm age and foundation motivation. In addition, eleven levels in association with reasons for BSL visualize the corresponding demographics by measuring their similarity on the dimensional planes assuming that the association exists between variables under consideration. Research design, data, and methodology - This study is done by the Ministry of SMEs and Startups in 2016 and examines 20,307 small and medium enterprises. For examining the distinct relationships among variables under consideration, both chi-squared test and correspondence analysis as main statistical tools are used. Results - The results show that among levels of reasons for BSL the three levels -weakening profitability, poor sales and economic depression- are main ones for the five demographics variables mentioned above, and we can obtain the detailed associations between attributes of corresponding variables by inspecting the two dimensional plane. Conclusions - This study suggests reasons for BSL are closely associated with the five different demographics variables - Administrative districts, Firm age, Occupations, Age of employer and Foundation motivation-by looking over results.

Differential Effects of Recovery Efforts on Products Attitudes (제품태도에 대한 회복노력의 차별적 효과)

  • Kim, Cheon-GIl;Choi, Jung-Mi
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.1
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    • pp.33-58
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    • 2008
  • Previous research has presupposed that the evaluation of consumer who received any recovery after experiencing product failure should be better than the evaluation of consumer who did not receive any recovery. The major purposes of this article are to examine impacts of product defect failures rather than service failures, and to explore effects of recovery on postrecovery product attitudes. First, this article deals with the occurrence of severe and unsevere failure and corresponding service recovery toward tangible products rather than intangible services. Contrary to intangible services, purchase and usage are separable for tangible products. This difference makes it clear that executing an recovery strategy toward tangible products is not plausible right after consumers find out product failures. The consumers may think about backgrounds and causes for the unpleasant events during the time gap between product failure and recovery. The deliberation may dilutes positive effects of recovery efforts. The recovery strategies which are provided to consumers experiencing product failures can be classified into three types. A recovery strategy can be implemented to provide consumers with a new product replacing the old defective product, a complimentary product for free, a discount at the time of the failure incident, or a coupon that can be used on the next visit. This strategy is defined as "a rewarding effort." Meanwhile a product failure may arise in exchange for its benefit. Then the product provider can suggest a detail explanation that the defect is hard to escape since it relates highly to the specific advantage to the product. The strategy may be called as "a strengthening effort." Another possible strategy is to recover negative attitude toward own brand by giving prominence to the disadvantages of a competing brand rather than the advantages of its own brand. The strategy is reflected as "a weakening effort." This paper emphasizes that, in order to confirm its effectiveness, a recovery strategy should be compared to being nothing done in response to the product failure. So the three types of recovery efforts is discussed in comparison to the situation involving no recovery effort. The strengthening strategy is to claim high relatedness of the product failure with another advantage, and expects the two-sidedness to ease consumers' complaints. The weakening strategy is to emphasize non-aversiveness of product failure, even if consumers choose another competitive brand. The two strategies can be effective in restoring to the original state, by providing plausible motives to accept the condition of product failure or by informing consumers of non-responsibility in the failure case. However the two may be less effective strategies than the rewarding strategy, since it tries to take care of the rehabilitation needs of consumers. Especially, the relative effect between the strengthening effort and the weakening effort may differ in terms of the severity of the product failure. A consumer who realizes a highly severe failure is likely to attach importance to the property which caused the failure. This implies that the strengthening effort would be less effective under the condition of high product severity. Meanwhile, the failing property is not diagnostic information in the condition of low failure severity. Consumers would not pay attention to non-diagnostic information, and with which they are not likely to change their attitudes. This implies that the strengthening effort would be more effective under the condition of low product severity. A 2 (product failure severity: high or low) X 4 (recovery strategies: rewarding, strengthening, weakening, or doing nothing) between-subjects design was employed. The particular levels of product failure severity and the types of recovery strategies were determined after a series of expert interviews. The dependent variable was product attitude after the recovery effort was provided. Subjects were 284 consumers who had an experience of cosmetics. Subjects were first given a product failure scenario and were asked to rate the comprehensibility of the failure scenario, the probability of raising complaints against the failure, and the subjective severity of the failure. After a recovery scenario was presented, its comprehensibility and overall evaluation were measured. The subjects assigned to the condition of no recovery effort were exposed to a short news article on the cosmetic industry. Next, subjects answered filler questions: 42 items of the need for cognitive closure and 16 items of need-to-evaluate. In the succeeding page a subject's product attitude was measured on an five-item, six-point scale, and a subject's repurchase intention on an three-item, six-point scale. After demographic variables of age and sex were asked, ten items of the subject's objective knowledge was checked. The results showed that the subjects formed more favorable evaluations after receiving rewarding efforts than after receiving either strengthening or weakening efforts. This is consistent with Hoffman, Kelley, and Rotalsky (1995) in that a tangible service recovery could be more effective that intangible efforts. Strengthening and weakening efforts also were effective compared to no recovery effort. So we found that generally any recovery increased products attitudes. The results hint us that a recovery strategy such as strengthening or weakening efforts, although it does not contain a specific reward, may have an effect on consumers experiencing severe unsatisfaction and strong complaint. Meanwhile, strengthening and weakening efforts were not expected to increase product attitudes under the condition of low severity of product failure. We can conclude that only a physical recovery effort may be recognized favorably as a firm's willingness to recover its fault by consumers experiencing low involvements. Results of the present experiment are explained in terms of the attribution theory. This article has a limitation that it utilized fictitious scenarios. Future research deserves to test a realistic effect of recovery for actual consumers. Recovery involves a direct, firsthand experience of ex-users. Recovery does not apply to non-users. The experience of receiving recovery efforts can be relatively more salient and accessible for the ex-users than for non-users. A recovery effort might be more likely to improve product attitude for the ex-users than for non-users. Also the present experiment did not include consumers who did not have an experience of the products and who did not perceive the occurrence of product failure. For the non-users and the ignorant consumers, the recovery efforts might lead to decreased product attitude and purchase intention. This is because the recovery trials may give an opportunity for them to notice the product failure.

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Factors governing dynamic response of steel-foam ceramic protected RC slabs under blast loads

  • Hou, Xiaomeng;Liu, Kunyu;Cao, Shaojun;Rong, Qin
    • Steel and Composite Structures
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    • v.33 no.3
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    • pp.333-346
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    • 2019
  • Foam ceramic materials contribute to the explosion effect weakening on concrete structures, due to the corresponding excellent energy absorption ability. The blast resistance of concrete members could be improved through steel-foam ceramics as protective cladding layers. An approach for the modeling of dynamic response of steel-foam ceramic protected reinforced concrete (Steel-FC-RC) slabs under blast loading was presented with the LS-DYNA software. The orthogonal analysis (five factors with five levels) under three degrees of blast loads was conducted. The influence rankings and trend laws were further analyzed. The dynamic displacement of the slab bottom was significantly reduced by increasing the thickness of steel plate, foam ceramic and RC slab, while the displacement decreased slightly as the steel yield strength and the compressive strength of concrete increased. However, the optimized efficiency of blast resistance decreases with factors increase to higher level. Moreover, an efficient design method was reported based on the orthogonal analysis.

Problem on the Governing Body of National Federation of Fisheries Cooperatives (NFFC) - from the perspective of the Honorary Office of NFFC President - (수산업협동조합중앙회장의 명예직화에서 본 지배구조의 문제점)

  • Jeon, Hyeong-Soo
    • The Journal of Fisheries Business Administration
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    • v.40 no.1
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    • pp.97-112
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    • 2009
  • The amendment of regulation affecting the Governing Body of NFFC (National Federation of Fisheries Cooperatives) has been known to the public in May 2008. Its essential points are as follow: 1) the President of NFFC shall be a non-standing officer. 2) the Full-Time Directors shall have the authority to deal with all subjects except for those especially reserved for the General Meeting or Board of Directors, while minimizing the authority of NFFC President. By providing this amendment, the government seeks to make the Governing body becomes professionalized and the management functions carried out by full-time professional board members. However, the amendment seems to pay no attention to the co-operative's identity and principles. In this context, five issues will be discussed: 1) Strengthening the separation between ownership and control of NFFC. 2) Weakening the authority of General Meeting. 3) The bounds of Audit Committee. 4) Consolidating the management control of the Full-Time Directors. 5) The loss of NFFC's Identity, followed by a summary and conclusion.

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Field Weakening Control for Five-Phase Induction Motor Drives considering the Effect of the 3rd Harmonic (3차 고조파의 영향을 고려한 5상 유도전동기의 약계자 운전)

  • Kang, Seong-Yun;Shin, Hye-Ung;Lee, Kyo-Beum
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.343-344
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    • 2015
  • 본 논문은 고속영역에서 3차 고조파의 영향을 고려한 5상 유도전동기의 약계자 운전을 제안한다. 5상 유도전동기는 집중권의 형태로 되어있어 공극 자속이 제 3차 공간 고조파 성분을 포함한다. 따라서 5상 유도전동기의 역기전력은 3차 고조파가 포함된 형태이므로, 5상 유도전동기의 약계자 운전은 3차 고조파 성분을 고려하여 수행해야 한다. 약계자 운전에 앞서 정격 이하의 속도에서는 간접벡터제어를 사용하고, 정격이상의 고속 영역에서는 최대 토크 발생과 전압 및 전류 제한 영역을 고려한 약계자 운전을 수행한다. 본 논문에서는 3차 고조파를 고려한 5상 유도전동기의 약계자 운전을 시뮬레이션으로 검증한다.

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The Medical Study on the Development of Pediatrics in Myeong(明) Dynasty (명대(明代)의 소아과학(小兒科學)에 관(關)한 연구(硏究))

  • Park, Hyun-Kuk;Kim, Ki-Wook;Yi, Yeong-Seok
    • Journal of Korean Medical classics
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    • v.21 no.3
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    • pp.1-25
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    • 2008
  • Myeong(明) Dynasty Period put together clinically various medical theory in Song(宋) Dynasty and Geum-Won(金元) age, organized medical system. They have been developed in theory, which thought of Byeonjeungronchi(辨證論治) more important, and clinical part which included diagnosis, therapy, prevention. In that age reactional medical thought was in fashion because of affect of Ihak(理學), therefore pediatrics have been affected from them. Especially, looking at the symptom of Byeonjeungronchi doctors, Manjeon(萬全), Nobaeksa(魯伯嗣), Wangdaeryun(王大綸), Wanggeungdang(王肯堂), Nuyeong(樓英) had succeed to Jeoneul(錢乙)' the five viscera Byeonjeung(辨證) system. Manjeon advocated Samyuyeosabujokron(三有餘四不足論) about Jangbu(臟腑) and organized the curative principle about Ojangheosil(五臟虛實). Gupyeong(寇平), commented on diagnosis of five viscera and classification of disease of five viscera. Wangdaeryun in the close of Myeong Dynasty Age explained main pulse, pulse of illness in detail according to weakness or strength of five viscera, pathological or physiological features of five viscera and Saenggeuk(生克) relation of Ohaeng(五行) in the book of "Yeongdongryuchwe(嬰童類萃)". Wanggeungdang and Nuyeong had organized system of argument which classified disease as a result of symptom of five viscera. "Yugwajeungchijunseung(幼科證治準繩)" and "Uihakgangmok(醫學綱目) Soabu(小兒部)" had been written by this principle. Nobaeksa had arranged the principle of cure about five viscera and explained method of common use about each organ's disease. Besides, Seolgi(薛己), Janggyeong-ak(張景岳), insisted about Myeongmun(命門) because he thought of Bisin(脾腎) of children and vigor by nature importance. Seolgi had applied and used very well Bojung-ikgitang(補中益氣湯) based on Idongwon(李東垣)'s Biwiseol(脾胃說) and controled and helped spleen and stomach. At the same time, he took a serious view about supplementing children's Sin-gi(腎氣) according to so many spleen and stomach disease was fallen because they couldn't make warm the spirit of Jungju(中州), result of weakening Hwa(火) of Myeongmun. Also Janggyeong-ak took a serious view strengthen of Bisin, so he assorted and used Insam(人蔘) and Buja(附子) to supplement children's weaken energy in kidney Jeonggi(精氣).

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