• Wind and Structures
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• v.30 no.2
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• pp.119-131
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• 2020

A butterfly web girder is a box-shaped girder with discretely distributed side openings along the spanwise direction. Until now, there have been few studies related to the aerodynamic performance of the butterfly web bridge. The objective of the current study was to clarify the effects of the side openings on the aerodynamic performance of the girder. Two butterfly web girders with side ratios B/D = 3.24 and 5, where B is the girder width and D is the depth, were examined through a series of wind tunnel tests. A comparison of the results for butterfly web girders and conventional box girders of the same shape confirmed that the side openings stabilized the vortex-induced vibration and galloping when B/D = 3.24, whereas the vortex-induced vibration and torsional flutter were stabilized when B/D = 5. The change in the flow field due to the side openings contributed to the stabilization against the vibration. These findings not only confirmed the good aerodynamic performance of the butterfly web bridge but also provided a new method to stabilize the box girder against aerodynamic instabilities via discretely distributed side openings.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.147-150
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• 2001

In the present work, a linear static analysis is presented for thin-walled prismatic box-beams made of generally anisotropic materials. A mixed beam theory has been used to model and carry out the analysis. Three different constitutive relations are assessed into the beam formulation. Simple layup cases having symmetric or anti-symmetric configuration have been chosen and tested to clearly show the effects of elastic couplings of the beam. Both 2D and 3D finite element structural analysis using the MSC/NASTRAN has been performed to validate the current analytical results. Results show that appropriate assumptions for the constitutive equations are important and prerequisite for the accurate prediction of beam stiffness constants and also for the beam behavior.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.147-154
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• 1999

This study was performed to survey the exchange of frames on 83 persons. We investigated frame size, frame type, binocular prism effect etc. 80.4% among motives of frame-exchanges was a damage or corrosion. The type of frames was round-like 62.4% and 37.6% square-like. The size of frames was $49{\Box}18$ and vertical length 33mm on old-frames, $47{\Box}17$ and 31mm on new-frames. The scope of axis variation was average +3.20~3.80. According to estimation by the rule of RAL-RG 915, the inappropriate horizontal prism effect of new spectacles was 42.2%, more than 38.5% on old spectacles. The inappropriate vertical prism effect was 24.1% on old, 33.7% on new spectacles.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.337-345
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• 2007

Nowadays, it is convenient to use 3D modeling tools for general planning before construction. Normally, a 3D model is built with 3D CAD such as 3D Studio Max, Maya, etc. or simply with AutoCAD. All these software packages are effective in building 3D models but difficult to use, because many provided functions and tools require prior knowledge to build both 2D and 3D designs. Moreover, the traditional method of building 3D models is most time-consuming as experienced operators and manual input are required. Therefore, how to minimize the building time of 3D models and provide easy-to-use functions for users who are not familiar with 3D modeling becomes important. In this paper, the VisualLISP programming language is used to create a convenient tool for efficient generation of 3D components for the AutoCAD environment. This tool will be demonstrated with the generation of a 3D sluice, an artificial passage for water fitted with a valve or gate to stop or regulate water flow. With the tool, users only need to enter the parameters of a sluice in the edit box and the 3D model will be automatically generated in a few seconds. By changing parameters in the edit box and pressing the "OK" button, a new 3D sluice model will be generated in a short while.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.961-966
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• 2003

In recent, the design of diaphragm which is representative disturbed region in PSC box girder bridge have been performed according to the empirical method or beam theory. But, these methods couldn't be described the behavior of the end diaphragm, and placed reinforcements accurately. As the compressive stress transferred by the web concentrated on the lower parts of diaphragm, it was demonstrated that the basic assumption of 2-D strut-and-tie model for the diaphragm that the compressive stress acts on the upper parts of the diaphragm is wrong. Meanwhile, in this research, after analyzing the variables of end diaphragm, the 2-D strut-and-tie models appropriate to each cases are proposed. And, the problems of 2-D strut-and-tie model were analyzed, so 3-D strut-and-tie model is proposed as well. There is no codes which include the demonstration of safety of 3-D strut-and-tie model. Hence, for nodes, the stresses at the elements which included the singular node in strut-and-tie model were investigated using the finite element analysis. And, the stress states of strut has one direction, so effective stresses were considered at the stage, dimensioning of the model. From the results, 3-D strut-and-tie model could predict the behavior of end diaphragm accurately, and design of reinforcement could be performed economically.

• Korean Journal of Community Nutrition
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• v.7 no.6
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• pp.824-832
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• 2002

The present study was conducted to evaluate nutritional intake by lunch-box of middle school girls who live in Chonbuk area. Anthropometric measurements and food intake from lunch-box over a three day period were investigated in a total of 110 middle school girls from rural (n＝37) and urban (n＝73) areas. The results are summarized as follows : 1. Not all the steamed rice in the lunch-box had enough mixed-cereal. 2. In the survey of food intake by food groups, 70.5% of the food came from the cereal group. 3. The intake of protein, phosphate, Vitamins $B_1 and B_2$, niacine and Vitamin E were adequate, however, the intake of other nutrients was significantly lower than those of one-third of the Korean RDA.4. Protein, lipid, and zinc intakes of the students from the rural area were significantly lower than those of students from the urban area. however, the carbohydrate and dietary fiber intakes of those in the rural area were significantly higher than those of the students in the urban area. 5. The percentage of calories from carbohydrate : protein lipid ratio was 67.6 : 12.2 : 16.9 for students in the rural area and 59.2 : 14.9 : 22.5 respectively for those in the urban area. In Summary, the intake of calcium, iron, Vitamins A, $B_6$, and D, folate and zinc from lunch-box in middle school girls was much lower than that of one-third of the Korean RDA. The intake of carbohydrate and dietary fiber of the students in the rural area was significantly higher, but that of protein, lipids, and zinc was lower than that of the students in the urban area. Therefore, nutritional education programs for both students and their parents should be provided to improve the daily food intake from lunch-box.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.189-196
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• 1993

Nucleotide sequences of nodD and nodA from Bradyrhizobium sp. SNUOOI were determined. The open reading frame (ORF) of nodD was 942 bp in length and encoded 314 amino acids. while ORF of nodA, sequence of which is the first one among legume symbionts Bradyrhizobium, was 630 bp and encoded 210 amino acids. The nucleotide sequence of nodD showed 99.4% homology with nodDI of B. japonicum USDAllO. while that of nodA showed 81.5% with B. sp. (Parasponial. At the 5' of nodYAB operon and nodD, consensus nod box sequences composed of 9 bp unit repeated four times and two times respectively were found. Also an A.T-rich sequence was found at 5' of nodD.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.111-117
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• 2017

In this paper, a local deformation effect in thin-walled box beams is investigated via a finite element modal analysis. The analysis is carried out for single-cell and multi-cell box beam configurations. The single-cell box beam with and without a neck, which mimics a simple wind-turbine blade, is analyzed first. The results obtained by shell elements are compared to those of one-dimensional(1D) beam elements. It is observed that the wall thickness plays a crucial role in the natural frequencies of the beam. The 1D beam analysis deviates from the shell analysis when the wall thickness is either thin or thick. The shell modes(local deformations) are dominant as it becomes thin, whereas the shear deformation effects are significant as it does thick. The analysis is extended to the single-cell box beam with a neck, in which the shell modes are confined to near the neck. Finally the multi-cell box beam with a taper, which is quite similar to real wind-turbine blade configuration, is considered to investigate the local deformation effect. The results reveal that the 1D beam analysis cannot match with the shell analysis due to the local deformation, especially for the lagwise frequencies. There are approximately 5~7% errors even if the number of segments is increased.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.4
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• pp.39-46
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• 2004

This experiment was carried out to study on the effect of surface coating on thermal insulation of farm structures to improve thermal resistance and reflective effect of solar radiation. Nine different types of experimental specimen were compared in the temperature variations of inside and outside; A, B, C, D. E and F types are box container and G, H and I types are drum container. The size of these containers is $1,500{\times}2,000{\times}2,500$ mm and ${\varphi}$ $280{\times}330$ mm, respectively. Specimen of 3-type box(A, B, C) is galvanized steel sheet of thickness 0.45 mm. D, E and F types are sandwich panel of the thickness 50 mm inserted with urethane, glass wool and polystyrene form, respectively. G, H and I types are paint pot using in general. The surface of A. D, E, F and I types didn't any treatment, B, C and G types were treated with thermal insulation coating on the outside surface(B, G) or the inside and outside surface(C). And H type was treated with water paint coating on the only outside surface. In general, the experimental results showed the following tendencies; In case of A, B and C types. it was found that the thermal insulation effect of types coated with thermal insulation coating was improved remarkably than that of no treatment. And the thermal insulation effect between steel sheet and sandwich panel type was nearly similar There was not a significant difference of thermal insulation effect between thermal insulation coating and water paint coating. In time of drum container filled with rough rice, The difference of heat transfer tendency and temperature variation among surface treatments was nearly similar that of box types of galvanized steel sheet. And there was time lag about 6 hours between the temperature of middle part of rice and that of inside or outside surface.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.199-203
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• 1999

This paper is on the DSP system design and implementation for real time MPEG-2 AAC multichannel audio, and MPEG-4 object oriented audio coding. This DSP system employs two DSPs of the state of the art TMS320C6701, developed by TI semiconductor. DSP board has PCI interface for downloading application program and control the system. DSP board was designed to use for both encoder and decoder, by setting several switches. The system contains external input and output box also, for A/D and D/A conversion for eight channel audio. The input box converts multi channel digital audio to ADI format, that provides serial interface for eight channel digital audio. And the output box converts ADI format signal to multi channel audio. Through this ADI interface, DSP boards can be connected to input, output box. Implemented DSP system was tested for integration with MPEG-2 AAC encoder and decoder S/W. Currently the DSP system performs realtime AAC 4-channel audio encoding with two DSPs, and 8-channel decoding with one DSP.