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Preconditioned Compressible Navier- Stokes Algorithm for Low Mach Number Flows (예조건화 압축성 알고리즘에 의한 저마하수 유동장 해석기법)

  • Ko Hyun;Yoon Woong-Sup
    • 한국전산유체공학회:학술대회논문집
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    • 1998.05a
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    • pp.35-42
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    • 1998
  • Time marching algorithms applied to compressible Navier-Stokes equation have a convergence problem at low Mach number. It is mainly due to the eigenvalue stiffness and pressure singularity as Mach number approaches to zero. Among the several methods to overcome the shortcomings of time marching scheme, time derivative preconditioning method have been used successfully. In this numerical analysis, we adopted a preconditioner of K.H. Chen and developed a two-dimensional, axisymmetric Navier-Stokes program. The steady state driven cavity flow and backward facing step flow problems were computed to confirm the accuracy and the robustness of preconditioned algorithm for low Mach number flows. And the transonic and supersonic flows insice the JPL axisymmetric nozzle internal flow is exampled to investigate the effects of preconditioning at high Mach number flow regime. Test results showed excellent agreement with the experimental data.

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DEVELOPMENT OF OCCUPANT CLASSIFICATION SYSTEM BASED ON DISTRIBUTED SYSTEM INTERFACE

  • Chang, K.B.;Lee, C.K.;Park, G.T.
    • International Journal of Automotive Technology
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    • v.7 no.2
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    • pp.195-199
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    • 2006
  • According to the United States FMVSS 208, every passenger car on the market after September of 2006 must install a safety system, which can deploy the airbag with different intensity or suppression based on the passenger type, to reduce infant and child injuries from airbag deployments. The Weight Classification System, which has been developed by Hyundai Autonet, is a system that classifies the person occupying the passenger seat. To overcome sensing problems due to the weight sensors small voltage, the Distributed Systems Interface is adopted.

Development of Software for the Preventive Maintenance (설비 예방보전을 위한 소프트웨어 개발)

  • 이장원;김원중
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.21 no.46
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    • pp.229-240
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    • 1998
  • In these days, we are facing the needs of the times that the product have to be converted from quantity to quality. Most companys now pay more attention to maximize efficiency of facilities with introducing high priced equipments, those equipments are too automated and electronic that partial failure or short time stop leads to the stop of producing process in the whole factory. Consequently, effective maintenance management of production equipment becomes a only solution against problems. This thesis develops a preventive maintenance software that grasp a failure sign through daily inspection with management item, Machine-Capability index and estimate a trend, determine the time of preventive maintenance. The software is useful to the plant operator in analyzing information easily and controlling preventive maintenance operations efficiently.

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The Emission Characteristics on Blending Ratios of Biodiesel Fuel and Diesel Fuel in a Common Rail Type Diesel Engine (커먼레일방식 디젤기관의 경유와 바이오디젤유의 혼합율에 따른 배기배출물 특성)

  • Choi, S.H.;Oh, Y.T.;Byeon, J.W.
    • Journal of Biosystems Engineering
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    • v.34 no.2
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    • pp.77-81
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    • 2009
  • Our nature is facing with serious problems related to the air pollution from automobiles in these days. Specially, the exhaust emissions from the diesel engine are recognized as a main cause influencing the environment severly. In this study, the potential possibility of biodiesel fuel is investigated as an alternative fuel for a naturally aspirated CRDi type diesel engine. The smoke emission of biodiesel fuel 5 vol-% was reduced by approximately 40% at 3000 rpm and full load in comparison with diesel fuel. On the other hand, the power, torque and brake specific energy consumption didn't show significant differences. NOx emission of biodiesel fuel was, however, increased compared with commercial diesel fuel.

Pagoda Data Management and Metadata Requirements for Libraries in Myanmar

  • Tin Tin Pipe;Kulthida Tuamsuk
    • Journal of Information Science Theory and Practice
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    • v.11 no.3
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    • pp.79-91
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    • 2023
  • The storage of data documentation for Myanmar pagodas has various issues, and its retrieval method causes problems for users and libraries. This study utilized a mixed-methods approach, combining qualitative and quantitative methods to investigate pagoda data management in Myanmar libraries. The study aims to achieve the following objectives: to study the library collection management of pagodas in Myanmar, to investigate the management of pagoda data in Myanmar libraries, and to identify the pagoda data requirements for metadata development from the library professional perspective. The study findings revealed several challenges facing librarians and library users in accessing and managing Myanmar pagoda data, including limited stocks and retrieval tools, difficulty in accessing all available data online, and a lack of a centralized database or repository for storing and retrieving pagoda data. The study recommends the establishment of metadata criteria for managing a set of pagoda data and improving access to technology to address these challenges.

An Empirical Study on the Model of Controls Evaluations for LAN

  • 노규성
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 1998.10a
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    • pp.385-391
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    • 1998
  • As the increase in the use of computers and rapid development of information technology exacerbate auditors' judgmental process, achieving objectives(effectiveness) of control and auditing with limited resources requires auditors to identify relative importance and priority of controls. Consequently, auditors' review and evaluation of internal control is been highlighted in modrn auditing process. Especially, as more organizations adopted LAN(Local Area Network) systems. LAN environment is facing with problems arising from characteristics of theLAN and the evaluation of LAN controls. The modern in this study is LAN control evaluation model with information system auditing objectives. This study concludes that auditors' proper evalution of the importance of LAN controls contributes to the effective achievement of IS auditing objectives.

A Study on Customer Segmentation for CRM Analysis (CRM 분석을 위한 고객 세분화에 관한 연구)

  • 송관배;양광모;강경식
    • Journal of the Korea Safety Management & Science
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    • v.5 no.3
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    • pp.133-143
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    • 2003
  • Even in the present situation where any general criterion on CRM dose not exist, utilization of CRM is expected to be actively continued, which will cause many problems. In this regard, evaluating CRM counts. As the result, projects are being suspended and budgets cut, plans for introducing CRM suspended or cancelled and many CRM software vendors and technical consulting firms are facing serious management crisis. Yet, this phenomenon can be regarded as an interim one. In fact, some cases that successfully introduced CRM show that CRM is migrating from small scale which is typical when introduced to larger scale through various tests. Therefore, this study tries to segment customer for the sloving the problem. And it make efficient customer management. Using this model, SN ratio of taguchi method for each of subjective factors as well as values of weights are used in this comprehensive method for customer. A example is presented to illustrate the model and to show a rank reversal when compared to a model that does not eliminate extreme values and eliminates the highest and lowest experts' values allocating the weights and the subjective factors.

A Study on Concept Analysis of Loneliness

  • Jung, Yun-kung;Lee, Jeong-hwa
    • Journal of Korean Clinical Health Science
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    • v.6 no.2
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    • pp.1097-1105
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    • 2018
  • Purpose: Loneliness is an extremely subjective experience that is influenced by life experiences and circumstances. This study attempted to provide basic data for the development of nursing intervention strategies to understand the concept of loneliness and to reduce loneliness on various topics. Methods: The research analysis method is based on the framework of concept analysis proposed by Walker and Avant (1988). Results: The results of this study are as follows: 1) Self-alienation 2) Isolation of human beings 3) Psychological damage reaction 4) Pain 5) Loneliness is the loss of a comfortable "frame". The prerequisites can be divided into personal characteristics and situational characteristics. Empirical criteria include intimate others, lack of social relationships or problems, family and friendship, belonging, recognition or expression of loneliness, emotional state changes and changes in health behavior, and physical symptoms. Conclusions: Loneliness is an important indicator of well-being and a cause of physical and mental illnesses, so nurses facing various subjects should be able to recognize the signs and symptoms of loneliness. By promoting and sustaining their interest, they should be able to enjoy lonely people.

Success Factors for Partnering Implementation in Construction: a Survey from Vietnam

  • Kim, Soo Yong;Le-Hoai, Long;Dang, Chau Ngoc
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.568-572
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    • 2015
  • Traditional procurement methods have revealed many disadvantages in construction fields such as the adversarial relationships between stakeholders. After several decades of application, partnering has shown to be an innovative arrangement that helped to reduce many problems existing in the traditional arrangement. In Vietnam, partnering has been applied for construction projects since the construction industry was facing many new challenges emanated from the global integration and economic booming. Partnering is rather new, so it needs to gain a better understanding of the new concept. This paper has identified twenty eight success factors for partnering in the Vietnamese construction industry. Five factors are considered critical to partnering success including financial security, commitment from top management, mutual trust between parties, adequate resources and effective communication. The findings could help construction practitioners to deploy the innovative procurement type and would also contribute to the global knowledge.

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Sharing CAD Models Based on Feature Ontology of Commands History

  • Seo, Tae-Sul;Lee, Yoon-Sook;Cheon, Sang-Uk;Han, Soon-Hung;Patil, Lalit;Dutta, Debasish
    • International Journal of CAD/CAM
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    • v.5 no.1
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    • pp.39-47
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    • 2005
  • Different CAx systems are being utilized throughout the product lifecycle due to the practical reasons in the supply chain and design processes. One of the major problems facing enterprises of today is how to share and exchange data among heterogeneous applications. Since different software applications use different terminologies, it is difficult to share and exchange the product data with internal and external partners. This paper presents a method to enhance the CAD model interoperability based on feature ontology. The feature ontology has been constructed based on the feature definition of modeling commands of CAD systems. A method for integration of semantic data has been proposed, implemented, and tested with two commercial CAD systems.