• Title/Summary/Keyword: Form of current

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An Efficient Method to Determine the Phase Current Commands of SR Motors for Minimum Torque Ripples (SR 모터의 토크리플을 최소화하는 상전류명령 결정 방법)

  • Kim, Chang-Hwan
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.49 no.4
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    • pp.78-89
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    • 2012
  • The generated torque of a switched reluctance(SR) motor is highly nonlinear, which makes it difficult to determine the reference current commands for minimum torque ripples. In this paper, we present a computationally simple and efficient method to minimize torque ripples of SR motors based on iterative learning control. The reference current command of each phase minimizing torque ripples is identified in 2-dimensional look-up table form. Our learning control algorithm does not require the torque model, so our method is not affected by model errors and hence is very accurate. In order to justify our work, we present some computer simulation results.

The Effect of Gap Size on Counter Current Flow Limitation Phenomena in Narrow Annular Gaps with Large Diameter

  • Jeong, Ji-Hwan;Lee, Seung-Jin;Park, Rae-Joon;Kim, Sang-Baek
    • Nuclear Engineering and Technology
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    • v.34 no.4
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    • pp.396-405
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    • 2002
  • An experimental study on counter-current flow limitation phenomena in narrow annular passages was carried out The gap sizes tested were 1, 2 and 3 mm. This is very small compared with the outer diameter of the annular passage, 500 mm. It was visually observed that a CCFL might occur in some part of the periphery while the other part is remained in a counter current flow pattern. That is, non-uniform behaviour of fluids due 4o a 2-dimensional effect appear in a large diameter facility. Because of this non-uniformity, a CCFL is defined in the present work as the situation where net water accumulation is sustained. That is, some amount of water should not be allowed to penetrate the gap and accumulate over the gap at CCFL criterion. The measured data are presented in the form of Wallis'type correlation with characteristic length of gap size. It was found that the present correlation is in good agreement with other empirical correlation based on measurements whose test section diameter is close and the gap size is much larger than that of the present test section.

A Study on the Expression of Traditionality in Korean Architecture (한국 근현대건축에 나타난 전통성 표현에 관한 연구)

  • Chung, Soon-Young;Yoon, In-Suk
    • Journal of architectural history
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    • v.8 no.3 s.20
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    • pp.53-64
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    • 1999
  • The subjects of the research is the architecture expressed traditionality from the time of the Open Port on, including North Korea region. The scope is divided into three periods; the first is from the Open Port to the Rehabilitation (光復),1945, the second is from then to 1960, and the last is from 1960 to the present. The expression of Koreanity(韓國性) should be concerned with the states at the time. In the beginning of the first period the alienate culture and the new modern facilities, like electricity, telecommunication system, train service, etc., rushes to Korea and the traditional architecture accepted the most of the new-comings; therefore, the original form was transformed. That seems to be the beginning of the discourse on traditionality in Korea architecture. The expression was showed up in four parts: ${\bullet}$ Korea traditional architecture accepting the foreign culture and the modern facilities ${\bullet}$ the compromise between foreign and traditional architectural form ${\bullet}$ the compromise between the Modem and traditional architecture ${\bullet}$ the Imperial Crown Style(帝冠樣式) which is the eclectic architecture with transformed roof. The figurative expression in the present architecture was showed up in roughly two parts: ${\bullet}$ the traditional form directly depicted wholly / partially ${\bullet}$ the abstract traditional form wholly / partially Moreover the results on the research traditional architecture have been collected, the principles have been drawn out. Especially the first beauty is not on form or figure of a building but on the composition of architectures and the harmony of the natural circumstances and architectures. So many contemporary architects make efforts to apply the principles to the composition and formation of current architecture.

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A Study on Tidal Current Energy in the Sea near Wando (완도해역의 조류에너지 자원에 관한 연구)

  • Yang, Chang-Jo
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.1
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    • pp.126-132
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    • 2011
  • With the worldwide trend of controlling the utilization fossil fuels inducing global climate change, many efforts will have to be made on securing stable supply of the energy due to UNFCCC. Tidal currents are a concentrated form of gravitational energy. Tidal current resource is significant, but limited locations. Technical and economic feasibility demonstration is the next needed step in the technology development process. So, we investigated overview of tidal in-stream energy in the sea near Wando, and then analytically estimated tidal energy resources and annual energy output of TECS arrays.

A Study on the Elements of Current Electronic Records (현용전자기록물의 메타데이터 요소에 관한 연구)

  • Choi, Sang-Mi;Lee, Sang-Yong
    • Journal of Korean Society of Archives and Records Management
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    • v.7 no.1
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    • pp.39-60
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    • 2007
  • This is a study based on the discussion of current electronic recordkeeping Metadata Standards. These standards form the basis for the International Standards. By analyzing ISO 23081, as well as the Metadata Standards used in Australia, England, and in the public records of Korea, the following were observed. This study puts forward the Metadata elements that apply to current electronic records and recognize their relevance and importance. Those elements can be used as the basis for establishing a future Korean Electronic Records Metadata Standard.

A Process Improvement in Building Constructions using Value Stream Analysis - Focused on slab works - (가치흐름 분석을 통한 건설공사의 공정개선방안 - 슬래브 공사를 중심으로 -)

  • Lee Hyung-Soo;Yoon You-Sang;Suh Sang-Wook;Jang Chan-Hee
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • autumn
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    • pp.527-530
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    • 2002
  • The purpose of this study is to present an improvement of the form work process. The current slab form work has waste factor by unnecessary process and not complete integration with the finishing process. Therefore the study used value stream analysis methodology for effective improvement of slab form work process. The main contents of the study are as follows; 1) Understanding of non-value adding activities in existing slab form work process 2) Process integration by value stream mapping 3) Effect analysis of time-cost reduction. The study recommends that, as a future research, development of tool and technique for the non-value adding activities are eliminated in building construction.

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A Study on the Status and Problem Concerning Overseas Shopping Service (중국의 해외구매대행 현황과 문제점에 관한 연구)

  • OH, Won-Suk;LI, Jing-Hua
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.65
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    • pp.141-160
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    • 2015
  • With the steady growth of our nation's economy, the purchase power of our domestic citizens has continuously enhanced. In recent years, online overseas shopping has rapidly warmed up, increasing number of Chinese people have started to purchase overseas products via internet. According to China's current legislation, the imported goods are divided into goods and items based on "profitability standard", and regulated by different rules of clearance supervision and import duties. Goods can't pass through custom and pay duties in the form of items, and the import duties burden of goods is generally much heavier than that of items. Goods of entrusted overseas shopping pass through custom and pay duties in the form of items, but goods of profitable purchasing are goods, not items. Therefore, the profitable-purchasing behavior is smuggling. Although goods of unprofitable purchasing are items, unprofitable-purchasing behavior may also constitute smuggling. The author concludes that causes of smuggling crime are: huge market demand for overseas goods, lack of customs supervision, law blank of petty foreign trade, and public's misconception of entrusted overseas purchasing are the major factors. The author proposes the corresponding preventive measures against the crime, such as to establish an one-stop service system in online Shopping Mall, to modify the Passengers' Baggage Declaration Form, to establish a relatively simplified clearance system of small cargo, to establish a relatively reasonable import duties of petty trade.

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A Study on the Prescriptions in the Five Viscera Section (五臟門) of Euibangyuchui (醫方類聚) - Focusing on the Form of Delivery for Medicinal Prescriptions - (『의방유취(醫方類聚)·오장문(五臟門)』의 처방 분석 -처방 제형을 중심으로 -)

  • Jung, Ji-Hun
    • The Journal of Korean Medical History
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    • v.31 no.1
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    • pp.105-122
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    • 2018
  • Most of the prescriptions currently used by Korean medicine institutions to treat patients are delivered in the form of decoctions. The author reviewed the five-viscera section (五臟門) of Euibangyoochui (醫方類聚), which is composed of theory, medicinals, diet, taboo, acupuncture and moxibustion, and exercises. The medicinals cover a total of 1,144 prescriptions cited from 14 medical books, and provides a wide range of prescriptions and delivery options, including decoctions, powders and pills. Of the 1,144 prescriptions, the author notes that among them, 577 prescriptions which use powders (41%) are the most popular; 444 are pills (31%) and are the second most popular; 329 decoctions (23%) are the third most popular, and 64 other prescriptions are 5 percent. Expanding treatment options and delivery of medicinal prescriptions presented in the five-viscera section (五臟門) of Euibangyoochui (醫方類聚), is beneficial to both patients and doctors. The author suggests that expansion of herbal treatment options will provide opportunities to overcome current treatment limitations in the Korean medical service industry.

Analysis of Surface Muscle Activity of Lower and Upper Musculus Erector Spinae According to Walkers form (보행기 형태에 따른 하지와 상지의 척추기립근의 표면 근활성도 분석)

  • Heo, Bo-Seob;Kim, Yong-Jae;Mun, Chae-Hwan;Son, Jae-Won;Hong, Seok-Jin
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.2
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    • pp.308-315
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    • 2014
  • The aims of this study are to analysis about surface muscle activity of lower and upper musculus erector spinae according to walkers form. The subjects of the current step is inconvenient to use a walker and five people over the age of 65 valid samples were selected as final. All the subjects were measured in three forms. Wireless EMG muscle activity is a measure of surface measurements were measured using a system, both musculus vastus lateralis, outside the erector spinae muscle, musculus biceps femoris, gastrocnemius muscle was attached to the channel electrodes. According to the results, First, gastrocnemius muscle activity showed significant differences by type of gait. Second, the muscle activity of the erector spinae muscle walking showed significant differences by type, side grip type showed the lowest muscle activity. Consequently, the present study is the efficient use of the four-wheel walker will provide the baseline data.

Case Study of Spatial Planning for the Efficient Use of Small Dwelling Space (소규모 주거공간의 효율적 활용을 위한 공간계획 사례연구)

  • Park, Si-Yoon;Kim, Jeong-Ah
    • Journal of the Korean housing association
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    • v.25 no.1
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    • pp.15-22
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    • 2014
  • In the domestic housing market, uncompleted lot-solid apartments and unoccupied residences are increasing in the medium-large scale area whose rents and transactions have been unstable, as going through the financial crisis and economical recession. Demands for small-scale housings are steadily increasing by practical consumer group who don't need large places, which are often not needed for the current people who are spending most of their time outside of their houses. Therefore, this study proposes the useful methods for spatial planning for small-scale houses for multiple households, including variable form, levels form, multi-level form, and smart-sizing. For efficient spatial planning for that purpose, here, small-scale housings are not limited to places for families with 1-2 members, but considered as one of broader approaches to graft various households and families. In addition, we examined the existed trends of researches about spatial utility of small-scale places, and did the research about the status of small-scale housing developments, and then proposed the direction for future small-scale housings by analyzing the advanced examples.