• International Journal of Highway Engineering
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• v.13 no.2
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• pp.147-157
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• 2011

As a background study to apply the reliability-based resistance factors to the domestic concrete bridge design code, a comparative study is conducted for the design results and the reliability indexes obtained by adopting different resistance factor formats to yield the design strength of concrete structures. The design results which are calculated by applying the section resistance factors of the current domestic design code and the material resistance factors of Eurocode are compared for the concrete beam bridge. The reliability index is calculated by considering the uncertainties involved in material, dimension and strength equation during the design procedure to get the strength of concrete structure. Also, the sensitivity analysis is performed to figure out which design variables have great impact on the reliability index. The resistance factors of the current domestic bridge design code, AASHTO LRFD and Eurocode are applied to the bridge design for flexure and shear strength and the results show that the resistance factors of the domestic code give the largest reliability indexes. It is observed that the probabilistic distribution of the live load makes difference for the reliability index and the yield strength of reinforcing steel and the live load have great impact on the reliability of both flexural and shear strength of concrete beam through the sensitivity analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6427-6433
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• 2013

For trains to run safely and quickly, the train should always follow the preceding train at a proper spacing. For this purpose, a certain distance between the stations is set for each block section. For the safe operation of trains in one block section, only one train service for an automatic block system is needed. The existing block system is composed an ABS, which is a linked track circuit and line sideway system through the interlocking system. The interlocking system is being replaced with a domestic electronic interlocking system. On the other hand, the block system still uses the relay format of an analog system, and is independently installed of the line sideway systems. Therefore, the existing block system has many problems in terms of construction and maintenance. In addition, the existing domestic line is used for ABS and LEU , which is installed separately, despite the train being controlled by the information of the same signal at the same location. This is not efficient in terms of each product price and the maintenance costs. This paper introduces an integrated electronic block system and the field test results. The field test was carried out through a periodic inspection performed eight times from January to late August.

• Journal of Korean Society of Steel Construction
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• v.30 no.2
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• pp.115-126
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• 2018

Internationally representative steel design standards have forbidden or limited the application of high-strength steels to tubular joints, partly because of concerns about their unique material characteristics such as high yield ratio. Most of design standards stipulate that for steels whose yield strengths exceed 355 or 360 MPa, the strength equations cannot be utilized or strength reduction factor below 1.0 should be multiplied. However, the mechanical background behind these limitations is not clear. Experimental testing of high-strength steel CHS (circular hollow section) X-joints recently conducted by the authors also clearly indicated that the current limitations might be unduly conservative. As a continuing work, extensive, test-validated numerical analyses were made to investigate the behavior of high-strength steel CHS X-joint under axial compression. Three steel grades covering ordinary to very high strength steels were considered in the analysis. Again it was found that the high strength penalty to the joint strength in current standards is too severe and needs to be relaxed. The high-strength steel joints under the effects of chord stress generally showed higher strength than the ordinary steel joints and their strengths were conservatively predicted by current standards. It is also emphasized that current format of the CHS X-joint strength equation does not reflect observed behavior and needs to be recast.

• Korean Journal of Computational Design and Engineering
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• v.21 no.4
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• pp.417-425
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• 2016

Especially for resolving BIM data compatibility issue, as one of recently raised BIM technology issues, has also been improved by using open BIM, representatively using IFC (Industry Foundation Classes) format. As shown in many case studies, usefulness of BIM technology is increasing day by day, and the IFC-based open BIM technology is essential in recent AEC projects where the productive collaboration is of importance. One of current problems in actual projects is that there is a conflict between conventional ways and newly developed BIM ways. Using both conventional and new technologies leads construction workers to having more work loads, consequently the efficiency and productivity of on-site workers have been decreased. Thus, it is strongly necessary to facilitate 3D BIM models to extract and generate 2D precision drawings in automation, especially using open BIM technologies. Some native BIM authoring tools have limitations in there automatic generation of 2D drawings, and there is no standardized mechanism to generate 2D drawings from heterogeneous applications. For this reason, this paper aims to develop an automated stand-alone program to generate 2D drawings in automation using IFC file, totally independent from various BIM authoring tools. By using the application described in this paper, any type of general drawings such as plan, section and elevation can be extracted without additional efforts. The development approach described in this paper, based on the open BIM technologies, has a strong impact to the current process especially in the perspective of enhancing productivity when we need to find out a trade-off in-between conventional and new approaches.

• The Research Journal of the Costume Culture
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• v.1 no.2
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• pp.131-144
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• 1993

Even though it has been to research on the variance of clothing pressure and on its effect of human body, it has not been available to evaluate the clothing pressure as an objective standard ta for the determination of an extra quantity of bodice' basic pattern. In this paper the basic pattern(the close adherence original shape) is determined by a drawing of plane figure after detaching an unweaving clothing from the inside of the gypsum, and the extra quantity is figured by a extension quantity when is formatted with 0.5, 1.0, 1.5 cm extra quantity longitudinal-cross section figures. With our experimental method, review the variance of clothing pressure according to difference of the extra quantity which was figured with subjects wearing experimental clothing including the extra quantity. The difference of the extra quantity was able to calculate with data form the subjects when anatomical position and five movements, then compare with subjects wearing non-extra quantity experimental clothing. The results of experiment as the follows : 1. There is only few body portions with the significant variance according to the increasing of he extra quantity at he body portion and the sleeve portion. 2. The clothing pressure of the sleeve portion was higher than the clothing pressure of the body portion. The difference of clothing pressure according to the variance of the extra quantity at the sleeve portion is more significant than the body portion. 3. Consider several important pressure points which wil be the No. 1 at the front of body portion. No. 17, 18 at the back of body portion and No. 21 at the sleeve portion. 4. It is important to have plane figure of gypsum when format an basis pattern.

• The Korea Journal of Herbology
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• v.20 no.4
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• pp.95-101
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• 2005

Objectives : In order to distinguish Cnidii Rhizoma and Ligustici Chuanxiong Rhizoma (cultivated in Korea and China), their external and internal states were observed via microscopic examination. Methods : The slice of the tested material made by paraffin section technique was colored with Safranine Malachite Green contrast methods, and then observed and photographed by olymphus-BHT. Results : Cnidii Rhizoma, Ligustici Chuanxiong Rhizoma (from Korea), and Ligustici Chuanxiong Rhizoma (from China) all demonstrated similar patterns as following : 1. external form 1) showing irregular nodular form with $2{\sim}7cm$ diameter. 2) having several trochites in parallel, and nodulose root trace on surface. 3) in addition to yellow-white or yellow-gray intersections, yellow-brown oil sacs were distributed, with cambium resembling a form of annulus. 2. internal form 1) its root and rhizome is composed of 10 layers of cork, with narrow cortical layers. 2) its phloem is wide, and oval light yellow-brown oil sacs are distributed around. The closer to the cambium, the smaller it is. 3) cambium is a form of a wave-like ring or an irregular polygon. 4) xylem and vessel are rare, most of which are arranged in a 'V' format, and sometimes xylem fiber is found. 5) pith is composed of parenchymatous cell, and parenchyma is full of starch grains. Conclusions : In conclusion, C officinale, L. chuanxiong (from Korea), and L. chuanxiong (from China) have rhizomes in a similar form with no special difference. Therefore, it is concluded that C. officinale, L. chuanxiong (from Korea), and L. chuanxiong (from China) are categorized into the same species.

• Journal of KIISE:Software and Applications
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• v.34 no.12
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• pp.1037-1044
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• 2007

Recently, we extract the representative melody of the music and index the music to reduce searching time at the content-based music retrieval system. The existing study has used MIDI data to extract a representative melody but it has a weak point that can use only MIDI data. Therefore, this paper proposes a representative melody retrieval method that can be use at all audio file format and uses digital signal processing. First, we use Fast Fourier Transform (FFT) and find the tempo and node for the representative melody retrieval. And we measure the frequency of high value that appears from PCM Data of each node. The point which the high value is gathering most is the starting point of a representative melody and an eight node from the starting point is a representative melody section of the audio data. To verity the performance of the method, we chose a thousand of the song and did the experiment to extract a representative melody from the song. In result, the accuracy of the extractive representative melody was 79.5% among the 737 songs which was found tempo.

• Steel and Composite Structures
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• v.23 no.3
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• pp.273-283
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• 2017

In this paper, it is aimed to present a detail investigation related to structural behavior of laterally unrestrained steel cantilever roof of tribune with slender cross section. The structure is located in Tutak town in $A{\breve{g}}r{{\i}}$ and collapsed on October 25, 2015 at eastern part of Turkey is considered as a case study. This mild sloped roof structure was built from a variable I beam, and supported on steel columns of 5.5 m height covering totally $240m^2$ closed area in plan. The roof of tribune collapsed completely without any indication during first snowfall after construction at midnight a winter day, fortunately before the opening hours. The meteorological records and observations of local persons are combined together to estimate the intensity of snow load in the region and it is compared with the code specified values. Also, the wide/thickness and height/thickness ratios for flange and web are evaluated according to the design codes. Three dimensional finite element model of the existing steel tribune roof is generated considering project drawings and site investigations using commercially available software ANSYS. The displacements, principal stresses and strains along to the cantilever length and column height are given as contour diagrams and graph format. In addition to site investigation, the numerical and analytical works conducted in this study indicate that the unequivocal reasons of the collapse are overloading action of snow load intensity, some mistakes made in the design of steel cantilever beams, insufficient strength and rigidity of the main structural elements, and construction workmanship errors.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1303-1308
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• 2007

Recently, precast concrete tracks are replacing ballast track for efficient and economic maintenance of track. Precast concrete railroad tracks are manufactured in factory, and transported to railroad construction site for installation. Therefore, quality of precast concrete track itself should be sufficiently good. On the contrary to the convenient manufacturing of precast concrete track, the installation of a precast concrete track requires careful steps. Typically, a precast concrete track is placed on an approximately 15-cm thick lean concrete layer. A mortar is filled between lean concrete layer and precast concrete track to adjust the sloping angle of a precast concrete track for a safe train operation at a curvy section. Then, the use of filled mortarproduces a void underneath a precast concrete track, which is harmful to structural safety of a precast concrete track undercyclic loading. Therefore, it is essential to make sure that there is no void left beneath a precast concrete track after mortar filling. In the continuous resonance method, the amplitude of frequency response measured using an instrumented hammer and an accelerometer is plotted against a pseudo-depth, which is half of the wave velocity divided by frequency. The frequency response functions are measured at consecutive measurement locations, 6-cm interval between measurement points, and then combined together to generate a 2-D plot of frequency response. The sections with strong reflections or large amplitude of frequency response are suspicious areas with internal voids and unfilled areas. The 2-D frequency response plot was efficient in locating problematic sections just by examining the color shade of a visualized plot in 2-D format. Some of the problematic sections were drilled to make a visual inspection of mortar filling. The visual image of interface between mortar and precast concrete track was verified using the validity of the continuous resonance technique adopted in this research.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.4
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• pp.312-320
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• 2017

This paper deals with the development of structural test facility for the strength assessment of marine leisure boat built from carbon fiber reinforced plastics (CFRP) materials. The structural test facility consists of test jig, load application and control system, and data acquisition system. Test jig, and load application and control system are designed to accommodate various size and short span to depth ratios of single skin, top-hat stiffened and sandwich constructions in plated structural format such as square and rectangular shapes. A lateral pressure load, typical and important applied load condition to the plates of the hull structure for marine leisure boat, is simulated by employing a number of hydraulic cylinders operated automatically and manually. To examine and operate the structural test facility, five carbon/epoxy based FRP square plates having the test section area of $1m^2$, which are part of CFRP marine leisure boat hull, are prepared and they are subjected to monotonically increasing lateral pressure loads. In the test preparation, considering the symmetry of the plates geometry, various strain gauges and linear variable displacement transformer are used in conjunction with data acquisition system utilizing LabVIEW. From the test observation, the responses of the CFRP hull structure of marine leisure boat are understood by obtaining load to deflection and strain to load curves.