• Journal of the Korea Convergence Society
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• 제10권12호
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• pp.257-262
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• 2019

Recently, the number of people enjoying various leisure sports has increased. As a result, the vehicles with various items loaded onto the roof can be easily seen on the street. The device that enables loading on the vehicle roof is called by a rack, and each vehicle has its own different shape. There are various types of roof racks but they must have the strength and durability to load heavy loads. In this study, the structural analysis was performed according to the support method of the roof rack and the shape of the fixture. Of three models, it was shown that model C had the best durability. Therefore, this study result shows which shape of the roof rack is most stable among the models. By utilizing the design data about a convergence study through the structural analysis due to the shape of automotive roof rack obtained on the basis of this result, the esthetic feeling can be shown by being converged onto the part of automobile at actual life.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1406-1412
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• 2001

Roof racks have become a very popular feature of vehicles as the market demand for SUV's and RV's has increased drastically over the years. Aeolian tone from the cross bars however. could be a source of severe discomfort for the passengers. Both experimental and numerical steps are taken to enhance the understanding of the generation mechanism of the wind noise. A successful reduction of the noise is achieved by imposing asymmetry in the section geometry, which reduces the strength of Karmann vortices shed downstream.

• Journal of the Korean Society for Precision Engineering
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• 제27권5호
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• pp.56-62
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• 2010

This paper presents the development process of roof carrier assembly using a one side release system for a vehicle. An RV(Recreational Vehicle) or SUV(Sports Utility Vehicle) has a roof carrier system on an upper surface of a roof panel for loading large or long size baggage. Such a roof carrier system is comprised of a roof rack longitudinally mounted on a roof panel and cross bar perpendicularly installed in the horizontal direction. Several locking mechanisms used in most vehicle roof carrier systems are composed with both side releasable locking ones. The obvious drawback to this arrangement is that when the user desires to reposition the cross bar, first one of the locking members must be unlocked and then the user must walk around to the opposite side of the vehicle to unlock the other member. In this paper, we proposed a newly locking mechanism, which allows a user simultaneously place both locking members of the roof carrier in locked and unlocked positions. In order to estimate design compatibility, structural and modal analysis is performed. Furthermore, a prototype based on the proposed design has been made, and then durability test carried out. From the simulation and experimental results, the proposed roof carrier system is proved effective and safe.

• Journal of the Korean Solar Energy Society
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• 제32권3호
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• pp.11-18
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• 2012

To expect accurately the maximum power of solar cell module under various installation conditions, it is required to know the performance characteristics like temperature dependence. Today, the PV (photovoltaic) market in Korea has been growing. Also BIPV (building integrated photovoltaic) systems are diversified and become popular. But thermal dependence of PV module is little known to customers and system installers. In IEC 61215,a regulation for testing the crystalline silicon solar cell module, the testing method is specified for modules. However there is limitation for testing the module with diverse application examples. In extreme installation method, there is no air flow between rear side of module and ambient, and it can induce temperature increase. In this paper, we studied the roof type installation of PV module on the surface of one-axis tracker system. We measured temperature on every component of PV module and compared to open-rack structure. As a result, we provide the foundation that explains temperature characteristics and NOCT (nominal operation cell temperature) difference. The detail description will be specified as the following paper.

• Journal of Bio-Environment Control
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• 제23권4호
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• pp.269-280
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• 2014

To cope with increasing of vegetables and flowers consumptions, horticulture facilities have been modernized. Korea government recently announced construction plan of new greenhouse complex at reclaimed land. However wind characteristics of reclaimed land is totally different from those of inland, wind pressure on greenhouse built in reclaimed land should be carefully evaluated to secure structural safety on the greenhouse. In this study, as a first step, wind pressure coefficient and local wind pressure coefficient on even-span greenhouse were measured using wind tunnel test. ESDU was adopted to realize wind characteristics of reclaimed land such as wind and turbulence profiles. From the wind tunnel test, when wind direction was 0 degree, it was concluded that KBC2009 standard underestimated scale of wind pressure coefficients at roof area of greenhouse whereas NEN-EN2002 standard underestimated those at every surface of greenhouse. When wind direction was 90 degree, both standards did not well reflect the characteristics of wind pressure distribution. From the analysis of local wind pressure coefficients according to wind direction conditions, design of covering, glazing bar of greenhouse where large effects of the local wind pressure were estimated should be well established. Wind pressure coefficients and local wind pressure coefficients according to parts of the greenhouse were finally suggested and these results could be practically used for suggesting new design standards of greenhouse.

• Journal of Bio-Environment Control
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• 제21권4호
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• pp.428-436
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• 2012

This study aimed to develop the multi-span plastic greenhouse which is suitable for tomato cultivation and is safe against climatic disasters such as typhoon or heavy snow. The width and heights of eaves and ridge of newly developed tomato greenhouse are 7, 4.5 and 6.5 m, respectively. The width is the same but the eaves and ridge heights are 1.8 and 2 m higher than conventional 1-2 W greenhouses, respectively. Cross beam has been designed as a truss structure so it can sustain loads of tomato and equipment. Tomato greenhouse has been designed according to climatic disaster preventing design standard maintaining the high height. In other words, the material dimensions and interval of materials including column and rafter have been set to stand against $40m{\cdot}s^{-1}$ of wind and 40 cm of snow. Tomato greenhouse has been equipped with rack-pinion type roof vents which have been used in glass greenhouse in order to prevent excessive rise in air temperature. This vent type is different from that of 1-2 W type greenhouse which is made by rolling up and down the vinyl at upper part of column. Roof vents are installed at ridge, and thus external air inflow and natural ventilation are maximized. As the height increases, heating cost increase as well and, therefore, tomato greenhouse has been equipped with multi-layered thermal curtain, of which thermo-keeping is excellent, to prevent heat from escaping.