• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.370-377
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• 2002

Generally, the system of calculation for the multi-path ultrasonic flow meters can be divided into two methods by how to get the mean velocity, namely, weighting and direct method. Weighting-method derive the mean velocity through modeling in theoretical velocity profile. Direct-method derive the mean velocity though actual flow distribution. The system of calculation varies with maker's transducer configuration and integration method. Each system has merits and demerits. This paper describes the system of integration that calculates line velocity over cross-section of the circular pipe. Flow rate mr discussed in this paper is a difference between theoretical flow rate and integrated flow rate according to values of Reynolds number in symmetric flow field or theoretical flow rate and integrated flow rate according to rotated model in asymmetric flow field.

• 산업공학
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• 제13권4호
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• pp.717-724
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• 2000

In this paper, an integrated system of optimal design, performance evaluation, and die design and manufacturing of axial fans for cooling tower is presented. The design and performance evaluation are developed based on three dimensional flow analysis so as to ensure low noise and high efficiency. The methodologies are implemented on computer as a GUI system including 3-D surface modeling and 2-D drawing file output modules. The CAD/CAM system is engaged to design the die and generate NC tool path, but the processes are also automated and integrated into the system by means of a part program coded from the design data. It is shown that the newly developed fans have superior performance and shortened lead-time compared to the existing dead-copied fans.

• International Journal of Computer Science & Network Security
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• 제21권2호
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• pp.130-141
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• 2021

This paper is in the intersection of software engineering and system engineering, two intimately intertwined disciplines. A dominating theme in this paper is the integral conceptualization of systems at large, as well as an underlying concern with software systems. In the software development life cycle, challenges still exist in translating requirements into a design artifact and then into an implementation (e.g., coding), then validating the results. From our perspective, software engineering requires an integrating paradigm toward a unified modeling orientation. Many methodologies, languages, and tools exist for facilitating system development processes. This paper is a venture into project development. To focus the materials, we concentrate on Harel's novel (and classic) development environment, which integrates a scenario-based engineering object orientation and statecharts through developing a railcar system. The railcar system is used as a detailed sample of translating requirements into a design artifact and then into an implementation, then validating the result. The project is re-cased as a single integrated modeling endeavor to be contrasted with the scenario and statecharts' development. The result of this scheme is an enriched understanding through experimenting with and contrasting various development methods of software projects.

• Korean Chemical Engineering Research
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• 제47권2호
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• pp.248-257
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• 2009

본 연구에서는 배출량산정모델과 다중매질모델을 활용하여 환경오염물질의 노출도를 예측하였으며 위해도를 평가하였다. 연구대상 화학물질로써 8종(아세트알데히드(acetaldehyde), 아크릴로니트릴(acrylonitrile), 아닐린(aniline), 벤젠(benzene), 사염화탄소(carbon tetrachloride), 디클로로메탄(dichloromethane), 포름알데히드(formaldehyde), 염화비닐(vinyl chloride))의 물질을 선택하였으며, 대상지역은 공단지역을 포함하는 도심 지역을 선택하였다. 배출량은 지리지형정보를 활용하여 점배출원과 비점배출원을 동시에 고려하여 산정하였으며, 다중매질모델은 지역적 특성을 반영할 수 있는 모델을 선택하였다. 유해성 자료는 미국 환경청의 IRIS(Integrated Risk Information System) 유해성 데이터베이스를 활용하였다. 모델링 자료와 유해성 자료를 이용하여 위해성을 평가한 결과, 물질별로 위해도가 높은 지역을 발견할 수 있었으며 우선적으로 관리해야 할 물질을 선별할 수 있었다.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 1997년도 한국전자거래학회 종합학술대회지
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• pp.263-268
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• 1997

Functional Modeling methodology, IDEF0 is widely used for modeling, analysis and description of enterprise system. The limitation of modeling components restricts applicability and give rise to confusion about model. In this paper, we propose new method to extend IDEF0. The first is adding modeling components which are semantic representations. In addition to ICOMs, we add the time and cost component which is required to execute the function. The second is tracing mechanism. When we need some information, we drive the functions related with the information by reverse tracing of the function which produces the information as a output and input. Through the tracing, we find out the bottleneck process or high cost process. Finally, we suggest the final decomposition level. We call the final decomposed function into unit function which has only one output data. We can combine and reconstruct some of functions because an unit function is similar to ‘lego block’. To reach the integrated system, the main problem to be solved is the integration of information produced by different functional subsystem. This can be resolved when the creation of data must be dependent on only one function. Through view integration of function output, we can guarantee the integrity of data.

• 대기
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• 제33권1호
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• pp.33-47
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• 2023

In this study, for the application of observation errors to the Korean Integrated Model (KIM) to utilize the Constellation Observing System for Meteorology, Ionosphere & Climate-2 (COSMIC-2) new satellites, the observation errors were diagnosed based on the Desroziers method using the cost function in the process of variational data assimilation. We calculated observation errors for all observational species being utilized for KIM and compared with their relative values. The observation error of the calculated the Global Navigation Satellite System Radio Occultation (GNSS RO) was about six times smaller than that of other satellites. In order to balance with other satellites, we conducted two experiments in which the GNSS RO data expanded by about twice the observation error. The performance of the analysis field was significantly improved in the tropics, where the COSMIC-2 data are more available, and in the Southern Hemisphere, where the influence of GNSS RO data is significantly greater. In particular, the prediction performance of the Southern Hemisphere was improved by doubling the observation error in global region, rather than doubling the COSMIC-2 data only in areas with high density, which seems to have been balanced with other observations.

• 한국시뮬레이션학회논문지
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• 제28권2호
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• pp.107-117
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• 2019

조선업은 한정된 자원을 사용하는 single-product production방식이며, 리소스를 효율적으로 관리하여 선박 공정의 생산성을 극대화 시킬 수 있는 생산관리기술이 중요하다. 때문에 많은 조선사에서는 모델링 및 시뮬레이션을 적용함으로써 현장 내 다양한 제약 조건이 고려된 선박 생산계획 및 공정에 대한 연구를 수행하고 있다. 하지만 기존 연구들은 갑작스런 일정 및 공정변경 시 정확한 생산계획을 제공하기 어려우며, 블록을 생산하는 각 공정 간의 상호연관성 파악이 어렵다. 뿐만 아니라, 블록의 세부 공정 및 일량을 고려하지 못하였기 때문에 생산계획과 현장계획에 많은 차이가 발생한다. 본 연구에서는 조선 내업공정 내 스케줄 된 전체 블록의 공정작업 순서 및 설계정보, 그리고 자원 제약을 고려하는 모델링 방법인 통합 프로세스 기반 모델 설계 방법을 제시한다. 통합 프로세스 기반 모델을 통해 사용자는 내업공정 내 블록 간의 조립관계, 정반정보 및 조립공정의 선후관계 파악이 용이하다. 또한 조선 내업공정에서 공유하는 리소스의 일량을 고려하여 부하 평준화를 진행하기 때문에 별도의 시뮬레이션 및 리소스의 모델링 절차 없이 리소스 효율을 최대화 할 수 있는 전체 생산계획을 얻을 수 있다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1751-1754
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• 2003

Due to advances in information technology, even Engineering Simulations can now be performed in web-based JAVA through an integrated operating system called Virtual Machine and the use of byte code, which guarantees the compatibility of identical codes in every computing system and makes it suitable for web-based simulation system development. This paper introduces an implementation embodied in JAVA Applet that allows a block-diagram type GUI that runs in a web browser for use in the dynamics simulation modeling of powertrains of vehicles and multi-body systems. This system is not restrained by any of the H/W and S/W in the user's computer, so that it has the advantage of providing a GUI that allows web-based block-diagram type modeling.

• 한국CDE학회논문집
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• 제6권2호
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• pp.140-146
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• 2001

A nuclear Power Plant is composed of a number of mechanical components. Maintaining the integrity of these components is one of the most critical issues in nuclear industry. In order to evaluate the integrity of these mechanical components, a lot of data are required including inspection data, geometrical data, material properties, etc. Therefore, an effective database system is essential to manage the integrity of nuclear power plant. For this purpose, an internet based virtual reality environment and web database system was proposed. The developed virtual reality environment provides realistic geometrical configurations of mechanical components using VRML (Virtual Reality Modeling Language). The virtual reality environment was linked with the web database, which can manage the required data for the integrity evaluation. The proposed system is able to share the information regarding the integrity evaluation through internet, and thus, will be suitable for an integrated system for the maintenance of mechanical components.

• 전기학회논문지
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• 제61권3호
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• pp.491-496
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• 2012

There are several protective relays used to protect DC traction power supply system for DC railway. These relays, however, are made by different manufactures and they have different ways for their operations. Therefore, there are difficulties for cooperation between the devices or the devices and an upper system. In order to increase interoperability and stability of the system composed of devices made by different manufactures, IEC 61850 international standards are applied to design logical nodes for modeling protective elements used in protective relays.