• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.5
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• pp.652-659
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• 2009

To analyze and verify the performance of a pulse radar without the real target data, there is a need to make the simulated signal which is similar to the received signal of the real target. In this paper, a method of the received signal generation for the pulse radar is proposed to solve the above need. The user-made scenarios are used to model the fast and small target and the clutter data based on the ground environment. These data are transformed into the electric signal using the proposed method. The efficiency of the proposed method is proved by comparing the signal of a field test with the simulated signal.

• Tunnel and Underground Space
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• v.15 no.6 s.59
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• pp.411-424
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• 2005

Weathering is defined as a process by which surface rock, once formed in the deep ground, is broken down and altered to keep the equilibrium with the ambient environment. In this study granitic rock samples of different weathering grades were collected in the field and the microscopic observation, X-ray diffraction analysis, electron microscopic observation, chemical analysis, and rock property tests were carried out. Formation of secondary minerals, especially clay minerals, by weathering was identified and the mechanism for the change of engineering properties such as rock strength degradation was analyzed. Tunnel model test, Failure behaviour, Shallow tunnel, Unsupproted tunnel length.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.425-431
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• 1994

THe dynamic characteristics of car are determined by ride quality and control stability. These characteristics are maintained by suspension, which is composed of springs, dampers and links. The values of these parameters are very important factor to determine the dynamic characteristic. Until now, most of company depends on trial-and-error method and driving test to solve this problem. But these methods are consumed many costs and time in developing process. In this paper,to minimize these difficulties,the proper model will be developed and analyzed the sensitivity of suspension parameter in time domain. On this ground, find the design parameter that have a dominant infuence on system response and estimate the change of system response values.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.113-121
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• 2010

Granular Compaction Pile are commonly used to improve bearing capacity and reduce settlements of soft soil in coastal and lowland areas. In this paper, through the field load test results of straight granular compaction piles and taper granular compaction piles, material properties of ground and GCP for numerical analysis were drawn and numerical model was established. In the numerical analysis of taper granular compaction piles with 3 different sections, a optimum dimension of taper granular compaction pile was considered at the side of settlement.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.413-420
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• 1998

In this study, an expert system is developed to evaluate a safety of tunnel structures. Using a dynamic finite element analysis module, this expert system predicts dynamic responses of a concrete lining surface which a transient force is applied on and estimates the condition between the concrete lining and surrounding ground. The evaluation parameter values of the module are multi-reflected wave frequency and amplitude of the dynamic responses. The multi-reflected wave frequency represents the depth of concrete lining, and the other parameter, the amplitude of the frequency, is utilized for detecting the internal flaws. A comparison of the dynamic responses between numerical and experimental model test verifies an effectiveness of this system. By this expert system, the safety of tunnel structures and the detection of internal flaws of concrete linings are estimated quantitatively.

• Management & Information Systems Review
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• v.24
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• pp.25-44
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• 2008

Small business have very different characteristics from large business; notable, small business suffer from resource and capacity poverty. Without knowing the relative importance of limited resources and capacity in small business, it have limited practical contribution to e-business implementation success. This paper develops an exploratory resource-based model of e-business implementation for small business with 42 sample companies. The results show that three types of resource factors; IS/IT vender supports, the level of IS/IT knowledge, and financial support. The implication for research is that the resource-based view of the firm and the test an exploratory framework of resource factors are useful theories to ground future work on e-business implementation in small business.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.599-604
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• 2017

Nowadays reactance method is being used as a technique for fault location in parallel feeding AC traction power system. However, implementation of this method requires a large number of field tests(ground fault) which is a huge burden on the operators. This paper presents a new estimation technique using quadratic interpolation to reduce number of times for field test and improves the accuracy of fault location. To verify a new technique, we solve AT feeding circuit and model it using PSCAD/EMTDC. Finally this paper conducts a comparative analysis of usefulness between a new technique and real field data.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.225-229
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• 2012

This paper proposes a reduced-scale simulator that can replace numerical analytic methods for the estimation of potential distribution caused by ground faults in various grounding systems. The simulator consists of a hemispherical electrolytic tank, a three-dimensional potential probe, a grounding electrode, and a data acquisition module. The potential distribution is measured using a potentiometer with a position-tracing function when a test current flows to the grounding electrode. Using the simulator, we could clearly analyze the potential distribution for a reduced- scale model by one-eightieth of the buried depth and length of the grounding rod and grounding grid. Once both the shape of the grounding electrode and the fault current are known, the actual potential distribution can be estimated.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.153-155
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• 2003

Laser scanning has become a viable technique for the collection of a large amount of accurate 3D point data densely distributed on the scanned object surface. The inherent 3D nature of the sub-randomly distributed point cloud provides abundant spatial information. To explore valuable spatial information from laser scanned data becomes an active research topic, for instance extracting digital elevation model, building models, and vegetation volumes. The sub-randomly distributed point cloud should be segmented and classified before the extraction of spatial information. This paper investigates some exist segmentation methods, and then proposes an octree-based split-and-merge segmentation method to divide lidar data into clusters belonging to 3D planes. Therefore, the classification of lidar data can be performed based on the derived attributes of extracted 3D planes. The test results of both ground and airborne lidar data show the potential of applying this method to extract spatial features from lidar data.

• Journal of Auto-vehicle Safety Association
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• v.14 no.4
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• pp.60-69
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• 2022

Recently, the importance of simulation validation in a virtual environment for autonomous driving system validation is increasing. At the same time, interest in the advancement of the virtual driving environment is also increasing. To develop autonomous driving technology, a simulation environment similar to the real-world environment is needed. For this reason, not only the road model is configured in the virtual driving environment, but also the driving environment configuration that includes the surrounding environments -traffic, object, etc- is necessary. In this article, FMTC, which is a test bed for autonomous vehicles, is implemented in a virtual environment and advanced to form a virtual driving environment similar to that of real FMTC. In addition, the similarity of the virtual driving environment is verified through comparative analysis with the real FMTC.