• 제목/요약/키워드: Preliminary study

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컴퓨터 그래픽스를 이용한 케이블 구조의 초기형태 설계 (Preliminary Form Design of Cable Structure using Computer Graphics)

  • 김남희;고현무;홍성걸
    • 한국전산구조공학회논문집
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    • 제24권4호
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    • pp.375-382
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    • 2011
  • 최근 컴퓨터 그래픽 S/W는 변수화 모델링과 생성알고리즘을 제공함으로써 기하학적 표현의 다양성뿐만 아니라 설계자의 의도를 체계적으로 모듈화할 수 있는 여러 가지 가능성을 열어주고 있다. 이 연구에서는 이러한 가능성을 지닌 컴퓨터 그래픽 S/W기반으로 초기 구조형태를 생성하는 방법을 제시하고자 한다. 특히 변수화 모델링과 생성 알고리즘을 이용하여 다양한 설계대안을 생성한다. 더욱이 동적 그래픽스개념을 이용하여 설계자가 한편에서는 구조형태를 생성하는 동안에, 또 다른 한편에서는 상응하는 힘의 흐름도가 마련되도록 한다. 이는 궁극적으로 힘의 흐름에 근거한 합리적 초기 구조형태 설계를 지원하게 될 것이다.

이익 공시시점과 주가지연반응 (Timing of Earnings Announcement and Post-Earnings-Announcement-Drift(PEAD))

  • 김형순
    • 아태비즈니스연구
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    • 제9권4호
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    • pp.137-155
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    • 2018
  • It has been reported that there is a significant positive relationship between the unexpected earnings on the earnings announcement date and the cumulative abnormal returns following the earnings announcement date. This study investigates whether the results of prior studies are because the public announcement of shareholders' meeting date was selected as the event date instead of either the preliminary earnings disclosure date or the profit/loss change announcement date. The results of this study are as follows. First, post-earnings-announcement drift(PEAD) occurs when unexpected earnings were computed based on the prior period earnings and the public announcement of the shareholders' meeting date as the profit disclosure date. Second, when analyzing the PEAD with the unexpected earnings calculated using the financial analysts' forecasts, no PEAD has been found both on the date of the shareholders' meeting and the earlier date of the preliminary earnings disclosure, profit/loss change announcement, or the public announcement of the shareholders' meeting. Foster et al. (1984) analyze the PEAD using time series model and earnings forecasting model and suggest that the PEAD appears only in the time series model. In this study, too, in the case of using analysts' profit forecasts, the lack of the PEAD shows that the PEAD can be changed according to the method of measuring the unexpected earnings.

웨딩플래너 선택속성에 관한 척도 개발 (Development of a scale for the selection criteria of wedding planners)

  • 김하정;유지헌
    • 복식문화연구
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    • 제27권4호
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    • pp.323-335
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    • 2019
  • Identifying the selection criteria of wedding planners, who are the main human resource that contribute to the overall satisfaction level of a wedding's preparation, can produce important data for the wedding industry as it faces a transition period. To develop a scale for wedding planner selection criteria, preliminary items were prepared based on in-depth interviews with an experienced wedding planner group and a comprehensive review of previous studies, such as studies on selection criteria in the wedding industry and service work similar to wedding planners and wedding planner selection criteria. The preliminary items were tested for content validity using a focus group interview, comprising people in the wedding industry, and were refined accordingly. Then, the definitive quantitative questionnaire items were developed after conducting a preliminary survey. The main survey for this study was conducted using the responses of 295 consumers taking an Internet questionnaire. Exploratory factor analysis, Cronbach's alpha, and confirmatory factor analysis were adopted to develop the scale, which was tested for convergent validity and discriminant validity. This study is academically significant in that it developed a selection criteria scale tailored to wedding planners to address an area that has not been covered in previous studies. It is recommended that future studies conduct empirical analyses using the selection criteria developed in this study to compare influential variables that could affect behavior intention.

박용 터보챠저 원심압축기의 공력설계에 대한 해석적 연구 (A Study on the Analysis for Aerodynamic design of centrifugal Compressor of the Marine Turbocharger)

  • 오국택;김홍원;갈상학;하지수;유승찬
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집E
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    • pp.649-654
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    • 2001
  • This paper describes aerodynamic preliminary design performance prediction and flow analysis for centrifugal compressor of the marine middle engine turbocharger. The performance characteristics of turbocharger compressor are investigated at various operating conditions using mass flow rate and revolution speed, and computational flow analysis for impeller and diffuser at design point are performed. Preliminary design results correspond to actual compressor geometric values comparatively by applying modified slip factor. Performance prediction and flow analysis results show good agreement with experiments. Therefore, this will provide the performance prediction in preliminary design, and help to increase the design capability for optimized impeller.

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축류 송퐁기의 공력학적 설계 (Aerodynamic Design of the Axial Fan)

  • 손상범;주원구;조강래;남형백;윤인규;남임우
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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    • pp.64-69
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    • 1998
  • In this study, a preliminary design method of the axial fan was systematically established based on the two-dimensional cascade theory. Flow deviation, lift coefficient, distribution of velocity and pressure coefficient on blade surfaces were predicted by an inviscid theory of Martensen method, which was also applied to select an airfoil of required performance in the present design process. The aerodynamic performance of designed blades can be predicted quickly and reasonably by using the through-flow calculation method in the preliminary design process. It would be recommendable to adopt three-dimensional viscous flow calculation at the final design refinement stage.

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노즐목 가변 추력기의 압력제어 기법에 관한 예비실험 결과 (Preliminary Experimental Results of Pressure Control for Modulatable Thruster Applications)

  • 최재성;허환일
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2011년도 제37회 추계학술대회논문집
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    • pp.18-21
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    • 2011
  • 본 연구에서는 노즐목 가변 추력기의 핀틀 구동에 따른 압력제어에 대한 기초 연구를 진행하였다. 실험을 위해 핀틀 추력기 및 핀틀 형상을 설계, 제작하였다. Fluent 유동해석을 통해 핀틀에 걸리는 하중을 분석하였고 이를 통해 구동기 모델을 선정하였다. 공압 시험 결과 핀틀이 전진함에 따라 추력기 내부 유동에 영향을 주어 압력에서 큰 오실레이션 현상이 발생하였다. 또한 핀틀의 위치가 노즐 수축부의 특정 위치에 전진하면서 추력기 성능에 영향을 끼치고 있음을 발견하였으며 공압시험을 통해 압력 제어의 가능성을 확인하였다.

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가스터빈 연소기 기본 설계 프로그램 개발 (Preliminary Design Program Development for Gas Turbine Combustor)

  • 김대식;김진아;진유인
    • 한국연소학회지
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    • 제20권3호
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    • pp.27-34
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    • 2015
  • The objective of the current study is to introduce detailed process for a preliminary combustor design, and to develop a computer code for it. The program includes various empirical and semi-empirical methodologies for diffuser deign, combustor sizing, air distribution, and sub-component design such as primary and secondary zones. Using the developed program, the combustor sizing results are shown from an assumption of simple annual combustor cycle analysis. Two options are employed, 1) pressure loss approach, and 2) velocity assumption approach. Design results show that there are no significant differences in combustor sizing between two design options. Further code improvement is required for performance and emission evaluations of the designed combustor.

COMPUTERIZED T-SCAN SYSTEM을 이용한 정량적 교합분석방법에 관한 연구 (A PRELIMINARY STUDY ON QUANTITATIVE ANALYSIS USING THE COMPUTERIZED T-SCAN SYSTEM)

  • 양재호
    • 대한치과보철학회지
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    • 제27권2호
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    • pp.271-277
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    • 1989
  • The purpose of this preliminary report was to describe the operating procedure of T-scan system and to identify the location, timing and force of occlusal contact in patient with normal occlusion using computerized T-scan system. From the preliminary observation , the author obtained the following results. 1. T-scan system displayed 2 dimensional and 3 dimensional description of occlusion: contact locations, timing (sequence) and forces of occlusal contacts. 2. The T-scan sensor was the most important part of the T-scan system. 3. The data of T-scan system cannot be stored in computer diskett. 4. The T-scan system is thought to be the most effective system to detect occlusal contacts and can be applied to the followings : occlusal diagnosis, occlusal equilibration, crown and bridge restorative procedures, denture adjustment, implant procedures, splint adjustment, laboratory procedures, periodontal treatment, orthodontics, TMJ treatment and patient education etc.

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초기설계 단계에서의 잠수함 수평발사 모델링 연구 (A Study on the modeling of horizontal launch at submarine in the preliminary design phase)

  • 김동훈
    • 한국군사과학기술학회지
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    • 제7권3호
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    • pp.38-46
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    • 2004
  • This paper deals with the development of simulation model for the horizontal launch at submarines in the preliminary design phase. The simulation model is composed of submarine motion model, cross flow force model in the bow of submarine, and weapon motion model In launch through torpedo tubes. Using submarine and weapon characteristics and simulation condition, it can simulate the exit velocity of weapon through torpedo tubes and reaction forces. It should be helpful for the analysis of the safe launch and design requirements in the preliminary design phase of a submarine or a weapon launched through torpedo tubes.

UNCITRAL의 해상화물운송협약의 예비초안에 관한 연구 (A Study on the UNCITRAL's Preliminary Draft Instrument on the Carriage of Goods by Sea)

  • 최명국
    • 무역상무연구
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    • 제20권
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    • pp.267-292
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    • 2003
  • UNCITRAL considered a proposal to include in its work program a review of current practices and laws in the area of the international carriage of goods by sea, with a view to establishing the need for uniform rules where no such rules existed and with a view to achieving greater uniformity of laws. And UNCITRAL Working Party, as of April, 2003, is reviewing the UNCITRAL's Preliminary Draft Instrument which was originally prepared by CMI. As said above, the Preliminary Draft Instrument has a lot of improved provisions in relation to the scope of application, period of responsibility, obligations and liability of carrier, obligations of shipper and so on, but it has also some provisions which should be reconsidered in light of changed environments. Therefore, UNCITRAL Working Party has to prepare more complete and widely adoptable new uniform rules under the sufficient discussion.

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