• Title/Summary/Keyword: D-D Diagram

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Some Considerations of the Ignition Delay Period in D.I Diesel Engine (직접분사식 디젤기관의 착화지연기간에 대한 고찰)

  • Bang, Joong-Cheol
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.2
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    • pp.97-103
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    • 2010
  • The four combustion stages in a diesel engine have close correlation among them. Especially, the ignition delay period has significant effect on the following combustion stage. And the period is also one of inevitable combustion processes in the diesel engine. For example, the diesel knocking is a well-known phenomenon due to the long ignition delay period. The interval of the ignition delay period is affected by the mixture formation process in the cylinder. However, in the case of the D.I. diesel engine, the available duration to make the mixture formation of air-fuel is very short. In addition, the means of the mixture formation mainly depends on the injection characteristics and properties of the fuel. It is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this study, using the visible engine, we measured the ignition delay period by photo sensor which detect occurrence of flame and presented the factors of the injection characteristics such as kinds of injection system, the injection pressure and the injection timing. The relation between the ignition delay period and cylinder pressure diagram which was concurrently obtained was also estimated.

A Comparative Study of the Shapes of 3D Virtual Skirts and Actually Made Skirts (3차원 가상스커트와 실물제작 스커트의 명상 비교연구)

  • Lee, So-Young;Kang, In-Ae
    • Journal of the Korean Society of Costume
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    • v.59 no.8
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    • pp.26-36
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    • 2009
  • The aim of this study is to be the fundamental study for virtual clothing system of the future through a comparative analysis of the difference between a virtual frill skirt and a real frill skirt using a 3-dimensional Apparel cad system. Satin was selected as a comparative fabric of the real skirt and virtual skirt. And compared skirts are frilled 1.5widths, 2widths, and 2.5widths. In case of 1.5widths frilled, the real skirts and virtual skirts showed no significant difference except in shirring frill expression. However, in case of 2widths frilled, and 2.5widths frilled skirts, significant differences in the extent of frill flattening, the sectional diagram of the bottom hem, and the skirt shape. The virtual skirt showed that as its multiple proportion of frill increased, the sidelines of the skirt drooped and excessively extended, and collision detection that the belt was twisted and torn apart arose. Furthermore, not only the frill but also the shape of the skirt was transformed, and the bottom hems were widened back and forth, and the sectional diagram of the bottom hems were transformed into rounded shapes.

A Behavior Conformance Checker for Component Interfaces using UML State Machine Diagram (UML 상태기계 다이어그램을 이용한 컴포넌트 인터페이스의 행위 호환성 검증 도구)

  • Kim, Ho-Jun;Lee, Woo-Jin
    • The KIPS Transactions:PartD
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    • v.16D no.1
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    • pp.65-72
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    • 2009
  • Component based development has increasingly become important in the software industry. However, in the current component based development approach with UML, the absence of behavioral description of components brings about a cost problem which causes semantic errors on the testing phase. Accordingly we cannot grasp the usage pattern of component by its provided interfaces which refer to an abstraction of software component. And we cannot guarantee the behavioral conformance of the provided and required interfaces of components. In order to solve these problems, we describe the behaviors of component interfaces by state machine diagram and guarantee their behavior conformance at the modeling phase. We also propose a method to guarantee the behavior conformance of component interfaces with concept of observation equivalence and invocation consistency. And we provide an analyzing tool which checks interface behavior conformance.

Structure of Turbulent Premixed Opposed Impinging Jet Flame with Simultaneous PIV/OH PLIF Measurements (PIV/OH PLIF 동시측정을 이용한 난류 대향 분출 예혼합화염 구조 연구)

  • Cho, Yong-Jin;Kim, Ji-Ho;Cho, Tae-Young;Yoon, Young-Bin
    • Journal of the Korean Society of Combustion
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    • v.8 no.1
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    • pp.36-45
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    • 2003
  • The subject of turbulent premixed flames has been focused by many researchers for a number of decades. Especially, Borghi suggested a magnificent diagram classifying turbulent combustion areas and Lipatnikov and Chomiak modified this diagram. Recently, experimental techniques have been developed so that we can use PIV for measuring 2D velocity field and apply OH PLIF techniques for obtaining flame locations. In present study, a new diagram is proposed using strain rates and OH signal intensity. Thus, simultaneous PIV and OH PLIF measurements are used for shear strain rates and flame locations, respectively. It is believed that the shear strain rates represent flow characteristics such as turbulence intensity and the OH intensity indicates the flame characteristics such as burning velocities.

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A Study: UML for OOA and OOD

  • Rajagopal, D.;Thilakavalli, K.
    • International Journal of Knowledge Content Development & Technology
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    • v.7 no.2
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    • pp.5-20
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    • 2017
  • The notion of object oriented analysis and design in software engineering has many rewards that aid the programmer to have an understanding of and improve the program efficaciously. Object oriented metrics helps rather a lot to a programmer or developer to comprehend and unravel the thing-oriented trouble readily and exactly. Object oriented metrics helps in examining the usefulness of object oriented applied sciences or in simple phrases Object-oriented metrics depict characteristics of object-oriented programming. The intention of this paper is to have an understanding of concerning the UML, Object oriented evaluation and design and the way it plays in UML.

A Study on the Application of Scheduling & Planning for Nuclear R &D Projects : Cas of LMR Project (원자력연구개발사업의 공정관리 적용 사례 연구)

  • 한도희
    • Journal of Korea Technology Innovation Society
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    • v.2 no.3
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    • pp.118-128
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    • 1999
  • This study attempts to provide an efficient method for managing the Nuclear R&D projects. It should be noted that the technology and experiences to develop a well-balanced plan and mon-itoring for the R&D project are not yet well established when compared with the commercial con-structionand engineering projects. This study recommends that the R&D project manager utilize the scheduling techniques to establish an integral management system taking in to account the un-certainties in the research environment. Based upon the results of a case study for the Liquid Metal Reactor Design Technology Development Project which is led by the KAERI this study also con-firms that it is possible to run the national nuclear R&D projects with the Scheduling & Planning.

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