• The Journal of Engineering Geology
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• v.19 no.1
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• pp.63-70
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• 2009

The optical fiber cable acting as a sensor was embedded in the underground research tunnel and portal area in order to monitor their stability and the spatial temperature variation. This system includes two types of sensing function to monitor the distributed strain and temperature along the line, where sensor cable is installed, not a point sensing. According to the results of one year monitoring around the KURT, there is no significant displacement or movement at the tunnel wall and portal slope. However, it would be able to aware of some phenomena as an advance notice at the tunnel wall which indicates the fracturing in rockmass and shotcrete fragmentation before rock falls accidently as well as movement of earth slope. The measurement resolution for rock mass displacement is 1 mm per 1 m and it covers 30 km length with every 1m interval in minimum. In temperature, the cable measures the range of $-160{\sim}600^{\circ}C$ with $0.01^{\circ}C$ resolution according to the cable types. This means that it would be applicable to monitoring system for the safe operation of various kinds of facilities having static and/or dynamic characteristics, such as chemical plant, pipeline, rail, huge building, long and slim structures, bridge, subway and marine vessel. etc.

• Journal of Korean Society of Forest Science
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• v.82 no.2
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• pp.195-206
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• 1993

The purpose of this study is to provide a basis for establishing regional harvesting systems that ist the prerequisites for the forest mechanization. The factors restricting to the forest harvesting and logging methods from topographical aspects are studied for this purpose. Three main harvesting methods studied in this paper are : shortwood method, longwood method and full tree method. This study shows : the shortwood method is suitable for low, the longwood method for medium, the full tree method for high topographical conditions. For the logging methods, the focus of the study is on various ground based logging systems by animalpower, manpower, gravitation, wheeled & crawler vehicle and cable. The factors limiting the coverage of logging operation are slope and logging distance. The cable crane logging methods are classified by logging distance into short distance(to 300 or 400m), middle distance(to 700 or 800m) and long distance cable crane methods (over 700 or 800m). The wheeled vehicle method shows serious damages to forest resources, whereas the logging by log-line of the gravitation logging method and cable crane method tend to minimize such damages. The wheeled & crawler vehicle method also shows difficult to apply in the high slope conditions, whereas cable crane method can be applied to maximum 120% steep slope and uphill conditions.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.153-160
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• 2011

Recently there are many long span cable supported bridges like Cable Stayed Bridge and Suspension Bridge already constructed or planned. Reconsidering of proper design wind load of long span bridge is required since the meteorological value based on the data only from 1960s to 1995 has been used when we estimate the wind load for designing long span bridges. In this paper, the research area was confined to western and southern coasts where many long span bridges have constructed. The method of moment and the least-squares method were used to estimate the expected wind speeds of 100 year's return period for girder bridges and for 200 year's return period for long span bridges based on the Gumbel's distribution. As the return-period wind speed on the land face was revised because of recent high speed velocity, the revised return-period wind speed is increased by 17%. Compatibility of return-period wind speed was also evaluated using RMS (Root Mean Square) error method. Aa a result of this paper, the least-squares method is more compatible than the method of moment in the case of western and southern coasts in Korea.

• Journal of Korean Association for Spatial Structures
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• v.1 no.1 s.1
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• pp.34-42
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• 2001

The development of contemporary spatial structures for long-span roofs in China was initiated in the 19505. Space trusses, reticulated shells and cable suspended structures have been developing rapidly since 1980s. Recently there has been a growing interest in tensile membrane structures. Comprehensive theoretical study has been carried out parallel to the engineering application, which provided necessary theoretical support to the development of different types of spatial structures.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.119-126
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• 1999

In this paper, The program of design technique of Influence surface is presented for analysis of moving(live) load of long-span bridges such as suspension bridges. This program is verified by comparing with various numerical examples. The proposed program is calculated the design conditions for the initial equilibrium state of suspension bridges, hence it can be used to analysis of various 3-dimensional frame structure with cable system.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.1248-1253
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• 2005

The study is indispensable for the dynamic behaviors because this Cable-stayed long span bridge ; has a more flexible structure than normal bridge can have weaknesses which are impact factor, deflection and defectives etc. This study analyze the dynamic behavior by an analysis of the moving constant train force on railway with Midas/Civil that is a commercial finite element analysis tool about Extradosed PSC Bridge. Also it will be checked the dynamic behavior features and standard of the dynamic capability.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.9
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• pp.669-678
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• 2007

In this study, the ventilation characteristics is investigated numerically of the longitudinal ventilation method in the curved long road tunnel. Numerical work has been conducted for the jet fan location by utilizing the commercial finite-volume code, FLUENT. Configuration of the tunnel is three-lane, 1600 m long, $120m^2$ in area, 3000 m curvature radius. The velocity profile, distribution of mono-dioxide carbon and flow rate of air are examined in the tunnel. Through the analysis, it is found that the difference of ventilation flow rate Is a little by the jet fan location, but tunnel outlet setup (CASEIII) of jet fans is the most efficient concerned with CO concentration.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.94-102
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• 2015

The electronic ballast for HID lamps needs to ignite lamps even though the length from the ballast to lamp is far away. Therefore, it needs to do the research on a resonant ignition to turn on the HID lamps because the reduction of ignition voltage is not much depending on the distance. However, the parasitic capacitance is increased depending the length of the cable, and it affects the resonant frequency. The ignitor voltage can be increased drastically under the resonant ignition through frequency sweep, and it is the main reason of blowing up. Therefore, the clamping diode is proposed to suppress the voltage of the primary winding during resonant ignition.

• Explosives and Blasting
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• v.16 no.3
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• pp.25-34
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• 1998

This area is covered in Andesite of high compression strength and located in PUSAN SEO-KU. There are many old houses around shaft site. So, we must have a cautious blasting operation. A total of 40 blasts were test at DAE-SHIN Shaft site to study the magnitude and frequency characterization of blast-induced vibration. The effect of viblating frequency on structual damage and site-specific scaling to define th empirical equations were also discussed. The result can be summarized as follows: 1. Some empirical equations were obtained. $V=K\{{\frac{D}{W}}1/3\}^{-n}$ where the values for n and K are estimated to be -1.407 to -2.202 and 643.3489 to 7283.2104 respectively. 2. Dominant frequencies at short distance are in the range of about 75.0 to 91.8 Hz, with some exceptions of about 50Hz, Frequencies observed at long distance are in the range of 10 to 2Hz. It is apparent the shift of dominant frequency down to lower levels at long distance.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.655-662
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• 2011

For analyzing seismic performance of long-span bridge for multi-support excitation and preparing technically and efficiently for a variety of design demands, the new module on multiple excitation was built in a reliable non-linear analysis program(RCAHEST) by using Influence Line Method, and the study on structures was performed previously. Also, the result of the analysis through RCAHEST was compared and verified with commercial finite element analysis program SAP2000 by using the feature of Multi-Support Excitation. From these results, nonlinear time history analysis considering multi-support excitation was studied after designing FE model of Incheon cable-stayed bridge. It was proved that the maximum response of horizontal displacement decreased as the time delay was increasing at all nodes of bridge. And then the serviceability of analysis model was evaluated by performing ultimate analysis under changes in maximum acceleration of seismic load data.