• 농업과학연구
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• 제42권4호
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• pp.325-333
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• 2015

The ventilation systems composed three types of side vent (roll-up) 'SV', side vent+roof vent 'SV+RV', and side vent+roof fan 'SV+RF' with 7.5 m spacing, with specific set point temperatures for ventilation: SV ($35^{\circ}C$ open / $33^{\circ}C$ close), SV+RV or SV+RH ($35^{\circ}C$ open/$33^{\circ}C$ close for root ventilation and $37^{\circ}C$ open / $35^{\circ}C$ close for side vent). In the treatment of SV+RV, although the average daily maximum temperature inside the greenhouse temporarily increased by $38-40^{\circ}C$, thermal stress by high temperature did not occur and the disease incidence (%) of powdery mildew and downy mildew on the oriental melon were 25 - 75% lower than in the conventional SV treatment. In the SV treatment, the disease incidence (%) of powdery mildew and downy mildew were 1.4 - 7.7% and 4.2 - 15.9% for 'Deabakkul', and 20.3 - 22.8% and 2.8 - 11.3%, for 'Ildeungkkul'. The yield for one month was higher in the treatment of SV+RV than those in other treatments, with values of 2,105 kg/10a for 'Deabakkul' and 2,537 kg/10a for 'Ildeungkkul'. The simultaneous treatment with side vent and roof vent resulted in 16.2% higher yield (18.1% higher marketable yield) than that in the SV treatment for 'Deabakkul'.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2009년 춘계학술발표대회 논문집
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• pp.316-320
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• 2009

Recently, concerns about conserving proper size of urban green spaces and accessibility are increasing, regarding it as a solution to diverse urban environmental problems including pollution, ecosystem deterioration, urban climate change. Artificial ground greening such as green roofs is regarded as the only alternative that can conserve green spaces which are impossible to be secured on the ground. However, green roofs are not popularized yet and levels are very low in provincial cities despite of related technology development and support systems of related agencies. Based on the background, this study tries to present a theoretical basis of methods for green roofs, conducting green roof simulations and collecting ideas about problems and improving measures from green roof users. Finally, it aims to offer base data which help establish policy direction for activation of green roof technology. As a result of a simulation for verifying temperature reduction effect, it was possible to affirm effect of a plot that green roofs applied. Especially, it was revealed that a green roof method using ground covers such as mixed planting was the most effective way to reduce temperature. Activation methods for green roofs based on this study are as follows: First, it is a priority to readjust systems related to green roofs. Second, citizens' active and voluntary participation must be attained. Third, it is required to establish detailed promotion procedures which aim at actual conduct and to maintain an expert department which is able to manage and control the establishment. After conduct, continuous aftercare stages are also needed.

• 한국건축시공학회지
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• 제10권3호
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• pp.129-136
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• 2010

지붕 개폐형태의 대공간 막 구조물은 멀티미디어적인 요소 및 전천후 공간을 활용할 수 있지만, 다수의 연결 조인트에 의해 구조물이 형성되므로 누수에 취약한 문제점이 있다. 특히 개폐식 지붕 맞댐부위의 우수차단 시스템은 우수의 직접적인 유입을 차단하는 역할을 하고 있으므로 바람을 동반한 강우환경에서도 수밀성능이 요구된다. 따라서 상기의 환경 조건을 부여한 수밀성 실험을 통하여 우수차단 시스템의 디테일에 대한 수밀성능을 평가하고자 한다. 실험 결과, 모든 실험체에서 누수가 발생하였으며, 우수의 유입경로는 동일한 것으로 확인되었다. 특히, 바람에 의하여 물입자들이 구조물 내부로 들이치는 현상이 주원인이므로 이를 보완한 새로운 우수차단 시스템의 디테일이 요구된다. 이 연구를 통해 강우 환경과 바람 환경을 동시에 부여하였을 때 발생될 수 있는 우수 침입 경로를 확인하였으며, 수밀 성능 확보 유무가 사전에 검토되어 져야함을 알 수 있었다. 또한, 디테일을 사전에 작성하여 모형 수밀성 시험을 반드시 시행한 후 그 결과에 따라 설계 디테일의 변경, 개선, 보완시공을 하여야 할 것이다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1370-1373
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• 1993

In controlling a system having many variables to control and multi objectives to satisfy such as a roof crane system, it is often difficult to obtain fuzzy If-Then rules in usual ways. As an alternative, we can more easely obtain rules in such a manner that we obtain each independent group of rules using partial variables for a partial objective. In this case, obtained rules can be conflicting with each other and conventional inference methods cannot handle such rules effectively. In this paper, we propose a roof crane controller with optimal velocity profile generator and a fuzzy logic controller with an inference method suitable for such conflicting rules.

• Smart Structures and Systems
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• 제26권5호
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• pp.545-558
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• 2020

A design method of a Multiple Tuned Mass Damper (MTMD) system is presented for wind induced vibration control of a cable-supported roof structure. Modal contribution analysis is carried out to determine the dominating modes of the structure for the MTMD design. Two MTMD systems are developed for two most dominating modes. Each MTMD system is composed of multiple TMDs with small masses spread at multiple locations with large responses in the corresponding mode. Frequencies of TMDs are distributed uniformly within a range around the dominating frequencies of the roof structure to enhance the robustness of the MTMD system against uncertainties of structural frequencies. Parameter optimizations are carried out by minimizing objective functions regarding the structural responses, TMD strokes, robustness and mass cost. Two optimization approaches are used: Single Objective Approach (SOA) using Sequential Quadratic Programming (SQP) with multi-start method and Multi-Objective Approach (MOA) using Non-dominated Sorting Genetic Algorithm-II (NSGA-II). The computation efficiency of the MOA is found to be superior to the SOA with consistent optimization results. A Pareto optimal front is obtained regarding the control performance and the total weight of the TMDs, from which several specific design options are proposed. The final design may be selected based on the Pareto optimal front and other engineering factors.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.194-201
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• 2006

Roof-fairing and deflector system have been used on heavy-duty trucks to minimize aerodynamic drag force not only for driving stability of the truck but also for energy saving by reducing the required driving power of the vehicle. In this study, a numerical simulation was carried out to see aerodynamic effect of the drag reducing device on the model vehicle. Drag and lift force generated on the five different models of the drag reducing system were calculated and compared them each other to see which type of device is efficient on the reduction of driving power of the vehicles quantitatively. An experiment has been done to see airflow characteristics on the model vehicles. Airflow patterns around the model vehicles were visualized by smoke generation method to compare the complexity of airflow around drag reducing device. From the results, the deflector systems(Model 5,6) were revealed as a better device for reduction of aerodynamic drag than the roof-fairing systems(Model 2,3,4) on the heavy-duty truck and it can be expected that over 10% of brake power of an engine can be saved on a tractor-trailer by the aerodynamic drag reducing device at normal speed range($80km/h{\sim}$).

• Structural Engineering and Mechanics
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• 제47권3호
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• pp.401-419
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• 2013

In this study, the efficiency of adaptive neuro-fuzzy inference system (ANFIS) and genetic expression programming (GEP) in predicting the effects of infill walls on base reactions and roof drift of reinforced concrete frames were investigated. Current standards generally consider weight and fundamental period of structures in predicting base reactions and roof drift of structures by neglecting numbers of floors, bays, shear walls and infilled bays. Number of stories, number of bays in x and y directions, ratio of shear wall areas to the floor area, ratio of bays with infilled walls to total number bays and existence of open story were selected as parameters in GEP and ANFIS modeling. GEP and ANFIS have been widely used as alternative approaches to model complex systems. The effects of these parameters on base reactions and roof drift of RC frames were studied using 3D finite element method on 216 building models. Results obtained from 3D FEM models were used to in training and testing ANFIS and GEP models. In ANFIS and GEP models, number of floors, number of bays, ratio of shear walls and ratio of infilled bays were selected as input parameters, and base reactions and roof drifts were selected as output parameters. Results showed that the ANFIS and GEP models are capable of accurately predicting the base reactions and roof drifts of RC frames used in the training and testing phase of the study. The GEP model results better prediction compared to ANFIS model.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.553-557
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• 2013

Roof and exterior wall are designed and constructed in a manner that prevents the accumulation of water within the wall and roof assembly in the formal building. However, in a freeform building there is no clear distinction between exterior wall and roof. In other words, the exterior walls and roof systems of the freeform building are integrated as a surface, unlike the formal building envelope. Therefore, freeform architecture needs a systemized envelope design method to perform functions of exterior wall and roof. However, in many cases, construction methods for roof and exterior wall are applied to freeform buildings without necessary alterations, which lead to incomplete design, leakage, cracks and other problems. Freeform architecture is thus designed and constructed differently from formal buildings. In order to more easily and inexpensively actualize freeform architecture, Building Information Modeling (hereinafter referred to as BIM) has recently been applied in the construction industry. The studies and case analysis are not sufficient to identify the implications and contributions of freeform buildings in future similar projects. Therefore, this research will study design and construction methods for freeform surfaces. This study attempts to analyze the pros and cons of each method for the concrete surface frame, and then presents the panel options for envelope system of the freeform architecture.

• Wind and Structures
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• 제32권1호
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• pp.55-69
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• 2021

Ultrapure ferritic stainless steel provides a new generation of long-span metal roof systems with continuous welding technology, which exhibits many unknown behaviors during wind excitation. This study focuses on the wind-resistant capacity of a new continuous welding stainless steel roof (CWSSR) system. Full-scale testing on the welding joints and the CWSSR system is performed under uniaxial tension and static ultimate wind uplift loadings, respectively. A finite element model is developed with mesh refinement optimization and is further validated with the testing results, which provides a reliable way of investigating the parameter effect on the wind-induced structural responses, namely, the width and thickness of the roof sheeting and welding height. Research results show that the CWSSR system has predominant wind-resistant performance and can bear an ultimate wind uplift loading of 10.4 kPa without observable failures. The welding joints achieve equivalent mechanical behaviors as those of base material is produced with the current of 65 A. Independent structural responses can be found for the roof sheeting of the CWSSR system, and the maximum displacement appears at the middle of the roof sheeting, while the maximum stress appears at the connection supports between the roof sheeting with a significant stress concentration effect. The responses of the CWSSR system are greatly influenced by the width and thickness of the roof sheeting but are less influenced by the welding height.

• Wind and Structures
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• 제19권6호
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• pp.603-621
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• 2014

Past high speed wind events have exposed the vulnerability of the roof systems of existing light-framed wood structures to uplift loading, contributing greatly to economic and human loss. This paper further investigates the behaviour of light-framed wood structures under the uplift loading of a realistic pressure distribution. A three-dimensional finite-element model is first developed to capture the behaviour of a recently completed full-scale experiment. After describing the components used to develop the numerical model, a comparison between the numerical prediction and experimental results in terms of the deflected shape at the roof-to-wall connections is presented to gain confidence in the numerical model. The model is then used to analyze the behaviour of the truss system under realistic and equivalent uniform pressure distributions and to perform an assessment of the use of the tributary area method to calculate the withdrawal force acting on the roof-to-wall connections.