• International conference on construction engineering and project management
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• 2024.07a
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• pp.645-652
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• 2024

Building Information Modeling (BIM) involves the integration of equipment information and component parameters across various engineering disciplines. The complex processes during model construction can lead to human errors. Furthermore, design changes often occur at various stages of the building's lifecycle, requiring designers and modelers to make timely modifications, resulting in significant costs and time consumption. Mechanical, electrical, and plumbing (MEP) design is considerably more complex than architectural design. Therefore, this study focuses on the automatic generation of a heating, ventilation, and air conditioning (HVAC) ductwork model with MEP design through BIM. Dynamo, a visual programming language (VPL), offers features such as arrangement, connectivity, and scalability. Thus, this research applied Dynamo to develop the Automatic Ductwork BIM Model Generation System. The BIM model generated by the system facilitates collaborative efforts and enables the analysis of HVAC System Conflicts. The system extracts coordinates for air handling units, supply air, and exhaust air outlets. The equipment is automatically positioned based on these coordinates, and the corresponding duct paths are generated by reading CAD files. At each duct connection point, appropriate fittings are fabricated according to specifications and dimensions. The duct system is configured with distinct colors, and the results are visualized in Revit, facilitating HVAC system clash detection in the future. This study undertakes a real project to validate the proposed system and processes and assesses its impact on modeling efficiency, real-time responsiveness, and accuracy, realizing automated ductwork generation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.1
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• pp.82-86
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• 1989

A study has been conducted experimentally on heat transfer characteristics of the heat exchangers with louvered fins in air. The experimental results are as follows; 1. Mean heat transfer coefficient is decreased with increasing temperature difference and model III is the best at constant temperature difference. 2. Pressure drop is increased with increasing air velocity, but it is decreased as the heat transfer area increases. 3. $\bar{h}/^{\Delta}p$ is increased and then decreased as air velocity increases.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.11 s.254
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• pp.1093-1100
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• 2006

Combustion stability rating of jet injector is conducted numerically using air-injection technique in a model chamber, where air is supplied to oxidizer and fuel manifolds of the model five-element injector head. A sample F(fuel)-O(oxidizer)-O-F impinging-jet injector is adopted. In this technique, we can simulate mixing process of streams flowing through oxidizer and fuel orifices under cold-flow condition without chemical reaction. The model chamber was designed based on the methodologies proposed in the previous work regarding geometrical dimensions and operating conditions. From numerical data, unstable regions can be identified and they are compared with those from air-injection acoustic and hot-fire tests. The present stability boundaries are in a good agreement with experimental results. The proposed numerical method can be applied cost-effectively to stability rating of jet injectors when mixing of fuel and oxidizer jets is the dominant process in instability triggering.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.3
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• pp.75-85
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• 2024

Airpower is a crucial force for suppressing military threats and achieving victory in wars. This study evaluates newly introduced fighter forces, considering factors such as fighter performance and power index, operational environment, capacity of each airbase, survivability, and force sustainment capability to determine the optimal deployment plan that maximizes operational effectiveness and efficiency. Research methods include optimization techniques such as MIP(mixed integer programming), allocation problems, and experimental design. This optimal allocation mathematical model is constructed based on various constraints such as survivability, mission criticality, and aircraft's performance data. The scope of the study focuses the fighter force and their operational radius is limited to major Air Force and joint operations, such as air interdiction, defensive counter-air operations, close air support, maritime operations and so on. This study aims to maximize the operational efficiency and effectiveness of fighter aircraft operations. The results of proposed model through experiments showed that it was for superior to the existing deployment plan in terms of operation and sustainment aspects when considering both wartime and peacetime.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.129-134
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• 2003

본 논문에서는 지표면 산란에 대한 모델을 개발하였고 이를 JPL AirSAR 측정데이터와 비교하였다. 식물이 없는 토양에서의 레이더 산란에 대해 새로 개발된 polarimetric empirical model(PEM)을 바탕으로, radiative transfer 이론을 이용하여 숲, 논, 밭 등 식물이 있는 토양에서의 레이더 산란 모델을 개발하였다. 지표면에서의 산란에 대해 개발된 이 모델을 AirSAR PACRIM-2 실험에서 얻은 측정 데이터와 비교하였다. 논, 채소밭, 풀 없는 토양, 소나무 숲 등에 대해 그 지역에서 얻은 지표면 변수를 이용한 산란모델 계산 결과를 측정 데이터와의 비교함으로써 이 산란모델의 사용가능 범위에 대한 논의가 이루어졌다.

• Journal of Biosystems Engineering
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• v.28 no.1
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• pp.35-44
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• 2003

This study was conducted to develop proper model for cold storage facility that could of for uniform heat movement and air movement f3r green grocery and improve improper design of the existing container-type cold storage facility. For that reason, new model(dome-type) cold storage facility was developed using 3-D CFD(computational fluid dynamics) simulation. The size was 6m${\times}$6m${\times}$5m. Its size and configuration were same to simulation model. Unit cooler was designed to send cold air in 4 side ways. A dome-type cold storage facility showed uniform distributions of air temperature and velocity because cold air was forced to move down along the ceiling and the wall and then circulated to the unit cooler from the central part of the floor. Dome-type cold storage facility also showed by low wind velocity, below 1 m/s that could minimized cold damage and quality deterioration.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.2
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• pp.37-48
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• 2014

Fighter squadron flight scheduling is the integrated air operation plan that is an important role for improving pilot's flight skill and maintaining combat readiness by efficient using available all air resources including pilot, aircrafts, air-weapons, fuel and supporting facilities etc. Korea airforce, however, has a limit as to an effective flight operation due to manual flight scheduling with scheduler's own experience and intuition. Therefore, in our study, we propose the optimization model of flight scheduling based on mixed integer programming. This model includes several constraints of realistic and essential quantified data related with flight schedule and can assign appropriate pilots optimally which are distinctive three type's solutions : flight, alert and duty crew schedules. Proposed solution method can be improved pilot's capability and allocated further air resources systematically and efficiently. In addition, it can be reduced a workload of flight scheduler and minimized obstructed factors of flight safety. Finally, we demonstrate the experiment's results for the check of efficiency and validity of this model.

• Journal of IKEEE
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• v.24 no.4
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• pp.1136-1140
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• 2020

As air pollution caused by fine dust becomes serious, interest in the spread of fine dust and prediction of air quality is increasing. The causes of fine dust are very diverse, and some fine dust naturally occurs through forest fires and yellow dust, but most of them are known to be caused by air pollutants from burning fossil fuels such as petroleum and coal or from automobile exhaust gas. In this paper, the CALPUFF model recommended by the US EPA is used, and CALPUFF diffusion modeling is performed by generating a wind field through the CALMET model as a meteorological preprocessing program that generates a three-dimensional wind field, which is a meteorological element required by CALPUFF. Through this, we propose a fine dust diffusion modeling and air quality prediction system that reflects complex topography.

• Journal of Environmental Health Sciences
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• v.22 no.4
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• pp.122-128
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• 1996

Many computer programs have been developed for meteorological and air quality simulation. Many of the model the U.S. EPA recommends are available as. part of UNAMAP. HIWAY-II can be used to estimate the concentrations of nonreactive pollutants from highway traffic. As a result, It was found that distribution of concentration wind speed was 1 m/s to 5 m/s were diminished to about 1/2. In our study, we measured air pollutants(CO), temperature and humidity to evaluate. Meteorological parameter were influenced by not only wind direction but also vertical.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.9
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• pp.23-28
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• 2019

In this study, flow analysis results according to different air cleaner and resonator configurations were used to investigate flow and velocity. Among models A, B, and C, model B had the higher speed and pressure. Model B is therefore considered suitable as an air cleaner. This study aims to design optimal shapes of air cleaners and resonators without noise sources.