• Title/Summary/Keyword: Gap Theory

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An Overview of Inventory Management with Some Suggested Research Topics

  • Silver, Edward A.
    • Journal of Korean Institute of Industrial Engineers
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    • v.34 no.4
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    • pp.373-385
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    • 2008
  • This paper presents an overview of inventory management. This includes a categorization, by a number of dimensions, of inventory problems and associated models. Relevant literature references are provided within the dimensions. The paper points out the continuing gap between theory and practice, followed by a number of suggested research topics to help bridge the gap.

The analysis of performance characteristics of a L.I.M with taken into consideration of end effect(II) -eddy current & air-gap flux density- (단부교리를 고려한 L.I.M의 동작특성 해석(II))

  • 임달호;장석명
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.36 no.4
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    • pp.240-251
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    • 1987
  • In this paper, with the end effect taken into consideration, the fundamental characteristics of a linear induction motor-the eddy currents of the secondary conducting sheet (traveller), the flux density in the air gap-are analysed by means of electromagnetic field theory. Accordingly, the derived governing eqations of the chatacteristics with goodness factor, presents that it was possible not only to predict the performance characteristics, but to obtain the data that needs to optimize a design of a motor with the reduction of the end effect.

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Band gap of Single-Layer Metal Monochalcogenides

  • Kim, Da-Jeong;;Hyeon, Jeong-Min
    • Proceeding of EDISON Challenge
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    • 2015.03a
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    • pp.392-395
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    • 2015
  • Metal Mono Chalcogenides(MMC)는 각각의 III족 metal 원자당한개의 chalchogen 원자를 갖고 있는(MX, M=Ga and In, X=S, Se, and Te)층상구조 화합물이다. MMC가 주목받는 가장 큰 이유는 single tetralayer MMC(SL-MMC)라는 2차원 구조를 갖기 때문이다. 2차원 물질은 다양한 물리적 현상을 증명하기 용이하다는 특징을 갖는다. 이 논문에서 우리는 SL-MMC중 Ga-MMC에서 chalchogen 원자가 변화함에 따라 바뀌는 실험 lattice constant를 조사하여 band gap과 formation energy를 Density Function Theory(DFT)로 계산했다.

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Ab initio study of MoS2 nanostructures

  • Cha, Janghwan
    • Proceeding of EDISON Challenge
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    • 2013.04a
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    • pp.214-216
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    • 2013
  • The atomic and electronic properties of molybdenum disurfide ($MoS_2$) nanostructures are investigated through density functional theory (DFT) calculations. We find that the band gap is indirect (about 1.79 eV) and direct (about 1.84 eV) in GGA for 2-dimensional $MoS_2$ in our calculations. On the other hand, 1-dimensional armchair nanoribbons have semiconductor properties (band gap is about 0.11~0.28 eV), while 1-dimensional zigzag nanoribbons are metallic.

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Dental Occlusion and Its Relationship to TMD and Systemic Symptoms (IV) - Myodontics Theory (교합이 악구강계 및 전신에 미치는 영향 (IV) - Myodontics Theory와 전신과 교합의 관계에 관하여 -)

  • Bae, Hanna Eun-Kyong;Park, Eun-Jin;Choi, Byeong-Gap
    • Journal of Dental Rehabilitation and Applied Science
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    • v.27 no.1
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    • pp.15-23
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    • 2011
  • This is the fourth series of article on dental occlusal relationship to TMD and systemic symptoms. In this part of the series, Myodontics theory is overviewed and its theoretical background, treatment sequence and methods are presented.

A Study on Engine Durability Considering Oil Consumption and Wear of Piston-Ring Pack and Cylinder Bore (피스톤 링 팩 및 실린더 보아 마모와 오일소모를 고려한 엔진 내구수명 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.155-163
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    • 2006
  • Ring, groove and cylinder bore wear may not be a problem in most current automotive engines. However, a small change in ring face, groove geometry and cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blowby and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings, grooves and cylinder bore are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be around the band of averaged test values or a little below.

A Study on Cylinder Bore Wear during Engine Durability Test (엔진 내구시험 시 실린더 보아의 마모에 관한 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.131-136
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    • 2006
  • Cylinder bore wear may not be a problem in most current automotive engines. However, a small change in cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each pare0s wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of cylinder bore diameter are obtained from three engines before and after engine durability test. The calculated wear data of cylinder bore diameter are turn out to be twice of the lower bound of averaged test values at TDC and the lower bound at BDC.

A Study on Ring Face and Groove Wear during Engine Durability Test (엔진 내구시험 시 링 외주면 및 그루브 마모에 관한 연구)

  • Chun Sang-Myung
    • Tribology and Lubricants
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    • v.22 no.4
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    • pp.211-217
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    • 2006
  • Ring and groove wear may not be a problem in most current automotive engines. However, a small change in ring face and groove geometry can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face, ring groove and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Being based on the calculation of gas flow amount by the theory of piston ring dynamics and gas flow, and the calculation of oil film thickness and friction force by the analysis of piston ring lubrication, the calculation theory of oil amount through top ring gap into combustion chamber will be set. This is estimated as engine oil consumption. Furthermore, the wear theories of ring, groove and cylinder bore are included. Then the each amount of wear is to be obtained. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. Next, the calculated amount of oil consumption and wear are compared with the guideline of each part's wear and oil consumption. So, the timing of part repair and engine life cycle can be predicted in advance without performing engine durability test. The wear data of rings and grooves are obtained from three engines before and after engine durability test. The calculated wear data of each part are turn out to be at the lower bound of aver-aged test values or a little below.

The Short-run and Long-run Dynamics Between Liquidity and Real Output Growth: An Empirical Study in Indonesia

  • JUMONO, Sapto;SOFYAN, Joel Faruk;SUGIYANTO, Sugiyanto;MALA, Chajar Matari Fath
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.5
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    • pp.595-605
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    • 2021
  • The objectives of this research are to see if the phenomena of "demand following" and "supply leading" exist in the business cycle, as well as to look at how liquidity and output react to changes in credit risk, investment-saving gap, inflation, exchange rate, and growth rate of real national output. Employing quarterly data of Maluku and North Maluku (2008-2019), this study utilizes VAR/VECM for inferential analysis. This research found three important findings. First, liquidity and output growth influenced each other in the long run. Second, the determinants of output growth for Maluku are liquidity, investment-saving gap, and inflation, while the determinants of liquidity are output-growth, the gap of investment-saving, and inflation. Third, the determinants of output growth for North Maluku are liquidity, credit risk, investment-saving gap, inflation, exchange rate, and the national output-growth, while the determinants of liquidity are output-growth, credit risk, investment-saving gap, inflation, exchange rate, and national output-growth. The findings of this study supported the hypothesis of demand following and supply leading theory in the Maluku and North Maluku business cycles. This study concludes that economic development would improve if supported by liquidity adequacy through increased deposit growth.

A Study on the Selection of Parameter for the Optimal Inductor Design using Fuzzy Theory (퍼지이론을 적용한 최적 인덕터 설계 파라미터 선정에 관한 연구)

  • 윤창선;배동관;김광헌;이재신;김병철
    • Proceedings of the KIPE Conference
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    • 1999.07a
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    • pp.58-61
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    • 1999
  • This paper describes the program of optimally choosing parameter in designing inductor, which applied by fuzzy theory, and verifies the reliability of program to use in design of power supply of electronic machine and information communication. It is available to find optimal value of complex and various parameter, such as core, winding, winding number, and air-gap, etc., needed on designing inductor. We expects to minimize time and cost of inductor design.

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