• Title/Summary/Keyword: Practical Equivalence

Search Result 41, Processing Time 0.03 seconds

Derivation and Implementation of Statistical Difference and Practical Equivalence Models in the Quality Improvement Processes (품질개선 프로세스에서 통계적 차이와 실제적 동등성 모형의 유도 및 적용방안)

  • Choi, Sung-Woon
    • Journal of the Korea Safety Management & Science
    • /
    • v.12 no.2
    • /
    • pp.217-223
    • /
    • 2010
  • The research proposes the complementary methodology using integrated hypothesis testing and confidence interval models that can be identified the statistical difference and practical equivalence. The models developed in this study can be used in the quality improvement processes such as QC story 15 steps. For the expressions of CI4LSD(Confidence Interval for Least Significant Difference) and CI4TOST(Confidence Interval for Two One-Sided Tests) are simple, quality practioners can efficiently handle them. CI4TOST models as a complement can be applied when CI4LSD models are influenced by sample size and precision.

Understanding and Misuse Type of Quality Improvement Tools According to the Kind of Data and the Number of Population in DMAIC Process of Six Sigma (식스시그마 DMAIC 프로세스에서 모집단의 수와 데이터 종류에 따른 품질개선 기법의 오적용 유형 및 이해)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
    • /
    • 2010.04a
    • /
    • pp.509-517
    • /
    • 2010
  • The paper proposes the misuse types of statistical quality tools according to the kind of data and the number of population in DMAIC process of six sigma. The result presented in this paper can be extended to the QC story 15 steps of QC circle. The study also provides the improvement methods about control chart, measurement system analysis, statistical difference, and practical equivalence.

  • PDF

A Study on Turbulent Characteristics in Swirling Coaxial Jets (선회 동축 분류의 난류특성에 관한 연구)

  • 이근오;김종현
    • Journal of the Korean Society of Safety
    • /
    • v.8 no.3
    • /
    • pp.19-25
    • /
    • 1993
  • This paper deals with the experimental study of the turbulent characteristics in the swirling coaxial Jets. In this research, the experimental study has been carried out to investigate the effects of swirl number and equivalence ratio on the flow characteristics in nonreacting flow field of the model combustor which symplifys the continuous type combustor for the practical use. Author particularly Intends to find out the fuel-air mixing In the recirculation zone In order to make sure the effects of swirl number and equivalence ratio on the stabilization of flame.

  • PDF

Extension of Backfire Limited Equivalence Ratio in Hydrogen Engine by Using Multi Point Ignition Method (다점점화에 의한 수소기관의 역화발생 억제효과에 관한 검토)

  • Kim, Y.Y.;Lee, C.W.;Lee, Jongtai
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.14 no.2
    • /
    • pp.131-137
    • /
    • 2003
  • Backfire occurrence must be controlled for the practical use of hydrogen fueled engine. It was found from preceeding studies that crevice volume around piston rings could effect a backfire occurrence. In this study, a possible countermeasure to backfire occurrence was evaluated by using multi point ignition method around piston ring. The results showed that backfire limited equivalence ratio was increased by a little due to a enhancing effect of mixture combustion around piston crevice volume.

Combustion Characteristics of HCCI Engine Fueled DME and Natural Gas(Unbalance of Cylinder-to-Cylinder and Effect of EGR) (DME/천연가스 HCCI 기관의 연소특성(기통 간 불균형과 EGR의 영향))

  • Jung, S.H.
    • Journal of Power System Engineering
    • /
    • v.14 no.3
    • /
    • pp.13-18
    • /
    • 2010
  • HCCI engines fueled DME and natural gas have been studied on single-cylinder engine due to availability of reducing on $NO_X$ and PM simultaneously without deteriorating into high thermal efficiency, and thus it is clarified that higher maximum engine load is achieved as DME equivalence is smaller. In this study, combustion tests were accomplished on multi-cylinder engine for practical use of it. When minimum DME equivalence achieved maximum engine load on single-cylinder engine was applied to 4-cylinders engine, there was in unstable running condition that engine revolution fluctuated greatly and cyclically. It is the reason what misfire occurred intermittently with one the same as minimum DME equivalence on single-cylinder due to increase in energy for ignition at No. 1 cylinder with lower cylinder liner temperature. Maximum engine load was achieved by adopting EGR, though it decreased because of knocking at smaller engine load than single-cylinder due to increase in minimum DME equivalence.

Evaluation on the Impact of the Rotterdam Rules on Facilitating the Use of Electronic Transport Reocrds (로테르담 규칙의 운송서류 전자화에 대한 영향 평가)

  • SUH, Paik-Hyun
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
    • /
    • v.75
    • /
    • pp.71-94
    • /
    • 2017
  • The Rotterdam Rules is the first international maritime carriage of goods Convention that acknowledge electronic records of contracts of carriage. The Rules have developed separate chapter in relation to electronic transport records' issuing, transfer, etc. This paper aims to evaluate Rotterdam Rules' contribution to the use of electronic transport records. To achieve the aims firstly this paper have examined the related articles of Rotterdam Rules, Secondly in practical aspects, this paper explores the opportunities and obstacles which could be happened in practical procedures, applicable to transport industry, shipper and holder of electronic transport records. Findings could be summarized as follows, first the Rules shows high acceptability to whom it may involved in transport industry by simplify the contents of the Rules to avoid conflict with each countries' national laws. The Rules acknowledge the functional equivalence between paper and electronic transport records in specific provisions. This could be important development to facilitate the use of electronic transport records. But the Rules have not mentioned liability limit of transport industry when the problems arise from issuing, tele-transmission, transfer of the records. And the secure of the functional equivalence between paper and electronic transport records also could be remained in uncertain regime due to different stance of each national laws.

  • PDF

A Study on the Stability of Rich/Lean Methane Premixed Flame (과농/희박 메탄 예혼합화염의 안정성에 관한 연구)

  • Lee, Won-Nam;Seo, Dong-Kyu
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.2
    • /
    • pp.170-177
    • /
    • 2005
  • The fuel-lean premixed flame has been considered one of the most efficient ways to reduce $NO_X$ emission during a combustion process. However, it is difficult to achieve stable fuel-lean premixed flames over the wide range of equivalence ratios: therefore, the application of fuel-lean flames to a practical combustion system is rather limited. In this study, the stability characteristics of fuel-lean flames stabilized by fuel-rich flames are investigated experimentally using a slot burner as a part of the basic research for practical application such as lean burn engines. Spontaneous emission of radical species were examined to understand the stability mechanisms of rich-lean premixed flames. The presence of fuel-rich flames could significantly lower the lean limit of fuel-lean flames. The stability of a fuel-lean flame is enhanced with the increase of fuel flow rate in a fuel-rich flame; how ever, it is not sensitive to the equivalence ratio of fuel-rich flames in the range of 1.2-2.4. The mechanisms of stable rich-lean premixed flames could be understood based on the characteristics of triple flame.

Experimental Investigation of Flame Stability in Continuous Flow Type Combustion Equipment (연속(連續) 연소장치(燃燒裝置)에 있어서 화염(火焰)의 안전성(安全性)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Lee, Keun-Oh;Kim, Yong-Soo;Yang, Ok-Yong
    • Journal of the Korean Society of Safety
    • /
    • v.2 no.1
    • /
    • pp.51-57
    • /
    • 1987
  • An experimental study was made of flame stabilization in unconfined turbulent swirling propane gas flames using various degrees of swirl and equivalence ratios. This study was carried out to investigate the effects of swirl number and equivalence ratio on the flow characteristics and the combustion characteristics in both nonreacting and reacting flow field of the model combustor which symplifys the continuous type combustor for the practical use.

  • PDF

Spectral Model of Turbulent Burning Velocity Taking Account of the Diffusivity of Deficient Reactant (부족성분 확산계수의 영향을 고려한 난류연소속도의 스펙트럼 모델)

  • 김준효
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.33 no.3
    • /
    • pp.218-225
    • /
    • 1997
  • The formerly proposed spectral model of turbulent burning velocity is refined for nonstoichiometric hydrocarbon mixtures. Refinements are made in regard to the following two points : (1) an effect of the diffusivity of deficient reactant on the turbulent burning velocity and (2) consideration of increasing laminar name thickness with a decrease in the laminar burning velocity A comparison between the predicted turbulent velocities and the measured ones is made. The predictions by the refined spectral model agree quantatively well with the experimental results in the regime of practical equivalence ratio, but not in the high and low equivalence ratio regime.

  • PDF

Nonlinear Optimal Control of an Input-Constrained and Enclosed Thermal Processing System

  • Gwak, Kwan-Woong;Masada, Glenn Y.
    • International Journal of Control, Automation, and Systems
    • /
    • v.6 no.2
    • /
    • pp.160-170
    • /
    • 2008
  • Temperature control of an enclosed thermal system which has many applications including Rapid Thermal Processing (RTP) of semiconductor wafers showed an input-constraint violation for nonlinear controllers due to inherent strong coupling between the elements [1]. In this paper, a constrained nonlinear optimal control design is developed, which accommodates input constraints using the linear algebraic equivalence of the nonlinear controllers, for the temperature control of an enclosed thermal process. First, it will be shown that design of nonlinear controllers is equivalent to solving a set of linear algebraic equations-the linear algebraic equivalence of nonlinear controllers (LAENC). Then an input-constrained nonlinear optimal controller is designed based on that LAENC using the constrained linear least squares method. Through numerical simulations, it is demonstrated that the proposed controller achieves the equivalent performances to the classical nonlinear controllers with less total energy consumption. Moreover, it generates the practical control solution, in other words, control solutions do not violate the input-constraints.