• Proceedings of the KSR Conference
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• 2010.06a
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• pp.947-953
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• 2010

The KTX-Sancheon has been commercially operating on the high-speed line since March. 2. In order to verify the performance of high-speed train and core equipments such as current collection system, sophisticated tests and evaluating procedures should have been considering. In this paper, the load cell with a built-in strain-gauge which developed to improve measuring method of contact force between the pantograph and catenary system is introduced. The static test results of the load cell shows that its design is very suitable and applicable for the dynamic test and on-line test. After the test and evaluation of load cell's dynamic calibration with pantograph, we will be applied to test interaction characteristics between the pantograph and catenary system on the high-speed line.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.295-296
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• 2011

The DRM+ is the newest digital radio standard for in-band environment. Although various state of the art technologies are adopted, the performance evaluation information is not sufficient. It is hard that many countries and stations considering the DRM+ as their digital radio standard check the performance of DRM+. To evaluate the performance of the DRM+ system, this paper depicts the laboratory trial results of DRM+ standard. In the laboratory trial, the rack type DRM+ test bed is built. To reflect the practical broadcasting environment, various tests are executed. Many countries and stations can efficiently use these test results, which are considering converting their analog radio broadcasting to digital broadcasting.

• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.301-312
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• 2016

In a concrete member under pure tension, the stress in concrete is uniformly distributed over the whole concrete section. It is supposed that a local bond failure occurs at each crack, and there is a relative slip between steel and surrounding concrete. The compatibility of deformation between the concrete and reinforcement is thus not maintained. The bond transfer length is a length of reinforcement adjacent to the crack where the compatibility of strain between the steel and concrete is not maintained because of partially bond breakdown and slip. It is an empirical measure of the bond characteristics of the reinforcement, incorporating bar diameter and surface characteristics such as texture. Based on results from a series of previously conducted long-term tests on eight restrained reinforced concrete slab specimens and material properties including creep and shrinkage of two concrete batches, the ratio of final bond transfer length after all shrinkage cracking, to THE initial bond transfer length is presented.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.65-73
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• 2001

This paper is a study on the fatigue analysis using BS5400 Part10(1980), code of practice for fatigue for a double link type level luffing jib crane which has been operated since the crane was built in 1985 at a domestic pier. South Korea. In addition, on the basis of the design lift due to fatigue analysis and the number of cracks detected from the nondestructive test the structural reliability and the residual life of the crane is predicted by evaluating the expected development of detectable fatigue oracle during the next five to ten years using Paris's Law for predicting fatigue crack growth and Gaussian probability density function to be reasonable for stress ranges below the mean values determined by laboratory tests. The statistical data used for the analysis of the structural reliability and life expectancy is given in the above referred code.

• Journal of the Korean Institute of Navigation
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• v.10 no.2
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• pp.11-29
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• 1986

As per the expanding needs of marine exploitation, many floating structures have been built. Among these, box-type vessel is considered as the most basic shape, to which plant barges and crane barges belong. Stability problem is very important for vessel. In order to increase transverse stability, this paper employs bulwarks along the upper deck sides of box-type vessels and the emphasis is laid upon the effect of bulwarks on transverse stability. In the present paper, the calculation method of heeling moment acting to the ship due to hydrostatic pressure is suggested, and actual procedures of the calculation for box-type vessels with bulwarks are shown. Furthermore corresponding model tests are carried out in small water tank. Through the comparison between calculated and measured values, it is confirmed that the preset calculation method is useful. And employing bulwarks on box-type vessels is very effective for increase of transverse stability at the heeling angles from about 15 degrees to about degrees.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.347-354
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• 2002

In this paper, when structures are constructed in the soft ground with poor bearing capacity at Incheon International Airport(railroad area), as for the grouting columns built In soft ground by high pressure jet grouting with Triple tube rod(super injection grouting), the effects on reinforcement and bearing capacity of ground are investigated. A unconfined compressive strength tests has been performed on the specimens sampled from the grouting columns and a mass plate bearing test has been performed on a grouting column. The test results show that super injection grouting has a sufficient effect on composite ground improved of foundation ground and reatraint of settlement of structure.

• Geomechanics and Engineering
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• v.14 no.1
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• pp.9-17
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• 2018

Brazilian splitting tests, uniaxial compression tests and triaxial compression tests are carried out on the coal samples cored from Shanxi group $II_1$ coal seam of Jiaozuo coal mine, Henan province, China, to obtain their property parameters. Considering the bedding has notable effect on the property parameter of coal, the samples with different bedding angles are prepared. The effects of bedding on the anisotropic characteristics of the coal seam are investigated. A geological geomechanical model is built based on the geology characteristics of the Jiaozuo coal mine target reservoir to study the effects of bedding on the fracture propagations during hydraulic fracturing. The effects of injection pressure, well completion method, in-situ stress difference coefficient, and fracturing fluid displacement on the fracture propagations are investigated. Results show bedding has notable effects on the property parameters of coal, which is the key factor affecting the anisotropy of coal. The hydraulic cracks trends to bifurcate and swerve at the bedding due to its low strength. Induced fractures are produced easily at the locations around the bedding. The bedding is beneficial to form a complicated fracture network. Experimental and numerical simulations can help to understand the effects of bedding on hydraulic fracturing in coalbed methane reservoirs.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.5
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• pp.147-158
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• 2008

Recently, Intelligent Transportation System (ITS) has been actively developed and built since the Transportation System Efficiency Promotion Act was enacted. However, since mutual connection among transportation information systems was not considered, the integration of transportation information services did not occur. Accordingly, the Ministry of Land Transport and Maritime Affairs established and announced the technical standard on ITS. In this study, the conformance testing of the transportation information and communication system interface standard on data exchange between the Transportation Information Center and terminals was researched The test items were categorized as data request tests and data providing tests by analyzing the communication procedures specified in the standard. A detail testing scenario was created for each item. The test assessment was established based on the conformance of data exchange procedures and the accuracy of data packet messages. Under the established technical standard, the number of times that tests should be performed was thought set to 30 and the success rate was set to 95%. The purpose of this study is to help the ITS of Korea perform the integrated management of transportation information by researching methods for conformance testing on the technical standard on ITS.

• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.59-65
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• 2006

A half-scaled large test model for the main components of the real annular structure was built and the thermal behaviors were experimented and obtained by thermal cyclic loads. The model design and the test conditions for the thermal loads were determined to take into consideration the thermal and mechanical loads acting on the real annular structure by finite element analyses. Temperature profiles and strains of the main components of the model were measured at an early stage of the test and periodically throughout the test in the given test conditions. After completion of the thermal cyclic tests, no evidence of crack initiation and propagation were identified by a dye penetration test. The measured strains at the critical parts were slightly increased proportionally with the increase in the number of the thermal cycles.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.367-368
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• 2002

The design of capsule body for self-propelled endoscope is important from the frictional resistance point of view. The capsule should be able to overcome the frictional resistance in order to move along the intestine. The motivation of this work was to gain a better understanding of the capsule body design on the frictional resistance of the capsule inside an intestine. A special experimental set-up was built to measure the frictional resistance as the capsule was being pulled inside the pig intestine specimen. Tests were performed with open and closed intestine specimens. Experimental data showed that smooth cylindrical capsule geometry resulted in the least frictional resistance. The resistance inside the closed intestine specimen was about four times higher than that of the open specimen. It is expected that the results of this work will be used to design the optimum propulsion system for the microendoscope.