• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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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.

• Journal of Korean Association for Spatial Structures
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• v.19 no.3
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• pp.93-100
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• 2019

In this study, the retractable-roof spatial structure was chosen as the analytical model and a tuned mass damper (TMD) was installed in the analytical model in order to control the seismic response. The analysis model is mainly consisted of runway trusses (RT) and transverse trusses (TT), and the displacement response was analyzed by installing TMD on those trusses. The mass of the single TMD which is installed in the analytical model was set to 1% of the total structure mass and the total TMD mass ratio was set to be 8% or 6%. In addition, the mass of a single TMD was varied depending on the number of installations. As a result of analyzing the optimal number of installations of TMD, the displacement response was reduced in all cases compared to the case without TMD. Above all, the case with 8 TMDs was the most effective in reducing he displacement response. However, in this case, as the load on the upper structure of the retractable-roof spatial structure increases, the total mass ratio of TMD was maintained and the number of TMDs was increased to reduce the mass ratio of one TMD.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.2
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• pp.103-108
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• 2009

Local exhaust system used in toilet and cooking place of low-rise public house installed roof ventilator at terminal of stack. There are many high riser public houses in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser public house depends on stack effect. But Neutral pressure level represents in a terminal of stack with air tightness for the best exhaust efficiency. Thereby, lower floors have the worst indoor air quality. This paper focuses mainly on the exhaust efficiency improved by roof fan with motor installed in high riser public house. It is observed there is higher exhaust efficiency than the existing natural roof ventilator.

• Journal of the Korean Institute of Rural Architecture
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• v.7 no.3
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• pp.27-35
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• 2005

This study is about finding out characteristic of recognition individual housing in seaside of Donghae. To accomplish this purpose, we survey the 150 houses related to the landscape. Thus the major analysis is to take basic data, such as image(modern, western, traditional, etc) about exterior form of housing corresponding to the landscape. The result summarized as follows First, the elements for the characteristic of recognition were exterior material finish, exterior color, roof type, roof material finish, window size, roof slope, area of wall vs roof. Second, the image of traditional housing was very insufficient to plan landscape of housing with design elements. This research suggests that landscape housing of future is to be environmental landscape design and the proper design is to be various considering not only user's preference but also control of landscape.

• Geomechanics and Engineering
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• v.19 no.3
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• pp.255-268
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• 2019

Taking top-coal caving mining face (TCCMF) as research object, this paper considers the combination of top-coal and immediate roof as cushion layer to build the solution model of support resistance based on the theory of elastic foundation beam. Meanwhile, the physical and mechanical properties of coal-rock combination influencing on strata behaviors is explored. The results illustrate that the subsidence of main roof in coal wall increases and the first weighting interval decreases with the increase of top-coal and immediate roof thicknesses as well as the decrease of top-coal and immediate roof elastic modulus. Moreover, the overlying strata reflecting on support has negative and positive relationship with top-coal thickness and immediate roof thickness, respectively. However, elastic modulus has limit influence on the dead weight of top-coal and immediate roof. As a result, it has similar roles on the increase of total support resistance and overlying strata reflecting on support in the limit range of roof control distance. In view of sensitive analysis causing the change of total support resistance, it can be regards as the rank of three components as immediate roof weight > overlying strata reflecting on support > top coal weight. Finally, combined with the monitoring data of support resistance in Qingdong 828, the validity of support resistance determined based on elastic foundation beam is demonstrated, and this method can be recommended to adopt for support type selecting in TCCMF.

• Geomechanics and Engineering
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• v.15 no.6
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• pp.1173-1182
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• 2018

The coal wall, gob-side backfill, and gangues in goaf, constitute the support system for Gob-side entry retaining (GER) in coal mines. Reasonably allocating and utilizing their bearing capacities are key scientific and technical issues for the safety and economic benefits of the GER technology. At first, a mechanical model of GER was established and a governing equation for coordinated bearing of the coal-backfill-gangue support system was derived to reveal the coordinated bearing mechanism. Then, considering the bearing characteristics of the coal wall, gob-side backfill and gangues in goaf, their quantitative design methods were proposed, respectively. Next, taking the No. 2201 haulage roadway serving the No. 7 coal seam in Jiangjiawan Mine, China, as an example, the design calculations showed that the strains of both the coal wall and gob-side backfill were larger than their allowable strains and the rotational angle of the lateral main roof was larger than its allowable rotational angle. Finally, flexible-rigid composite supporting technology and roof cutting technology were designed and used. In situ investigations showed that the deformation and failure of surrounding rocks were well controlled and both the coal wall and gob-side backfill remained stable. Taking the coal wall, gob-side backfill and gangues in goaf as a whole system, this research takes full consideration of their bearing properties and provides a quantitative basis for design of the support system.

• Geomechanics and Engineering
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• v.24 no.5
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• pp.479-490
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• 2021

Pre-drainage of groundwater in the roof aquifer by boreholes is the main method for prevention of roof water disaster, and the drop in the water level during the drainage leads to the variation of the local stress in the overlying strata. Based on a multitude of boreholes for groundwater drainage from aquifer above the 1303 mining face of Longyun Coal Mine, theoretical analysis and numerical simulation are used to investigate the local stress variation in the process of borehole drainage. The results show that due to the drop in the water level of the roof aquifer during the drainage, the stress around the borehole gradually evolved. From the center of the borehole to the outside, a stress-relaxed zone, a stress-elevated zone, and a stress-recovered zone are sequentially formed. Along with the expansion of drainage influence, the stress peak in the stress-elevated zone also moves to the outside. When the radius of influence develops to the maximum, the stress peak position no longer moves outward. When the coal mining face advances to the drainage influence range, the abutment pressure in front of the mining face is superimposed with the high local stress around the borehole, which increases the risk of stress concentration. The present study provides a reference for the stress concentration caused by borehole drainage, which can be potentially utilized in the optimal arrangement of drainage boreholes in underground mining.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.334-342
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• 2016

In order to evaluate the modified installation methods of roof ventilation devices, derived from the previous experiment ('investigation into the optimum capacity of roof ventilation devices and their deployment'), the conventional and modified (improved) roof ventilation systems were installed in the single-span plastic greenhouse for growing oriental melons. The roof vents ($60{\varphi}$) and roof fans (maximum air capacity of $38m^3/min$) were installed in the spacing of 15m (FT, modified 'side vent+roof fan' ventilation) and 6m (TT, modified 'side vent+roof vent' ventilation) respectively on the roof of greenhouses for the modified roof ventilation treatments, and 20m (FC, conventional 'side vent+roof fan' ventilation) and 8m (TC, conventional 'side vent+roof vent' ventilation) for the conventional ones. The stem diameter, leaf blade lengh, petiole length, and leaf width were lower in the FT and TT treatments than those in the conventional treatments, FC and TC. Although the fruit weight and total yields were slightly lower in the FT and TT treatments, the marketable fruit ratio (%) were higher, as a result of increased fruiting ratio (%) in these treatments, than those of FC and TC. The marketable yields (kg/10a) in the FT and TT treatments were 8,391 kg/10a and 7,283 kg/10a, which were respectively 661 kg/10a and 487 kg/10a higher than those in the treatments of FC and TC. The modified installation methods of roof fan resulted in production of more female flowers and lower fruit drop ratio (%) compared to conventional meathods. In the treatment of the conventional ventilation with roof vent, the fruit weight, fruit length & width, and flesh thickness were higher than in other treatments, but there were no significant differences in the fruit width and flesh thickness among the treatments.

• Korean Journal of Agricultural Science
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• v.39 no.2
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• pp.271-277
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• 2012

Dimensions, operation conditions and improvement items for round roof windows were investigated in arch shape single-span plastic greenhouse with roof vents, and natural ventilation performance was analyzed based on the ventilation theory. Diameter of round roof windows was mostly 60 cm, and chimney height projected on roof was average 30 cm. Installation space was mostly 5 to 6 m but farmhouse of 10 m and over was 16.7% also. A round roof window which has 60 cm diameter was installed to 6 m space generally and 80 cm diameter was installed to 10 m space, but correct standards did not exist. There were a lot of opinions that ventilation effect of round roof windows is fairly good and user satisfaction is generally excellent. It is problem that there is few effects in summer and that vinyl around each vent tears well and rainwater leaks, and improvement hope item required development of automatic control system. In the wind speed of 0.3 m/s, it was estimated that natural ventilation rates were 0.69, 0.55, 0.50 and 0.48 volumes per minute in case of 2, 4, 6 and 8 m installation space for round roof windows, respectively. It was analyzed that the ratio of ventilation due to buoyancy out of total ventilation were 65.2, 41.9, 29.9 and 22.8% in case of 2, 4, 6 and 8m installation space, respectively. By the round roof windows installed at space of 6 m, ventilation rate was estimated to 0.5 volumes per minute, and we can expect the increase in ventilation rate of 30%. In order to meet the recommended ventilation rate for summer season, we have to install the round roof windows at space of 1 to 2 m. However, it is difficult to apply those installation space because of falling productivity due to lower light transmittance as well as rising costs. It is estimated that the installation space of 6m is appropriate for spring or fall season. Therefore it is necessary to encourage installing the roof windows in single-span plastic greenhouses.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.613-617
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• 2004

This paper presents an experimental study on vibration characteristics of an automotive roof with viscoelastic material. The goal of the study is to extract modal parameters (natural frequency, loss factor, and mode shape) of automotive roof with unconstrained and constrained layer damping treatment. To determine the effective position of the viscoelastic patch on a roof, vibration tests have been carried out for two cases; Aluminum plate with viscoelastic patch on maximum strain energy, and aluminum plate with viscoelastic patch on nodal line. From the result of aluminum plate, it is found that the viscoelastic patch should be attached on the Place with maximum strain energy Part. For the automotive root five Patches of unconstrained or constrained viscoelastic material have been attached on the position of maximum strain energy. This paper addresses that the proper position of viscoelastic patch is very important and the concept of maximum strain energy may be a good criterion f3r the placement of viscoelastic patch.