• Architectural research
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• v.20 no.4
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• pp.137-145
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• 2018

The nondestructive test is widely used in the field of diagnosis and maintenance to evaluate the degree of damaging of structures caused by aging, and the demand for this test method is expected to continue increasing. However, there is a lack of standards related to the nondestructive test, and South Korea is relying heavily on developed nations for original technologies related to diagnosis. It is an urgent task to establish a nondestructive test method appropriate for the circumstance of South Korea. The purpose of this study is to compare and analyze estimated error of compressive strength in single-story structures comprised of vertical and horizontal reinforced concrete members using the impact testing method and rebound hardness method, which are nondestructive test methods, and to review on-site applicability of these methods. Based on compressive strength of the structures estimated, overall mean error was 21.2% for the impact testing method and 15.6% for the rebound hardness method. The necessity of a reliable diagnostic method based on compound nondestructive test methods to increase accuracy of estimation was confirmed.

• Journal of the Korean Geosynthetics Society
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• v.20 no.1
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• pp.35-44
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• 2021

This research studies the stabilization method for improved soil sloped through the on-site application of Paper Flyash ground stabilizers. The target strength required for improved soil is 500 kPa, and the compressive strength for the slope surface needs to be less than 1,000 kPa after the improvement in order to plant vegetation. To meet this condition, we mixed soil from the site and the ground stabilization material, which is the main material for surface improvement material, performed mixing design and conducted various tests including strength test, permeability test and plantation test. After analyzing the results of the compression test on improved soil slope, we proposed soil constants for the improved soil. In order to evaluate the applicability of the improved soil on the slope, the site construction was carried out on the collapsed slope and the reinforcement evaluation of the surface of the improvement soil was conducted. The stability was not secured before the reinforcement, but the test shows after the reinforcement with improved soil, the safety rate is secured up to 48 hours during the raining period. In addition, the compressive strength of the improved soil at the site was secured at more than 200 kPa adhesion as planned, and the soil hardness test result was also found to be within the specified value of 18-23 mm, which increased the resistance to rainfall and ability to grow plant on the surface for improved soil.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.105-112
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• 1999

In recent the superior economic benefits and the convenience of installation increased the use of geosynthetics, especially geogrids with the effects of high tensile strength. In this study, various tests were conducted to determine the physical and chemical properties of geogrids which contains durability under various critical conditions, creep behavior and the stability for installation damage in fields. With analysis of test results, the partial and total safety factors were determined and presented the long term design strength of flexible geogrids.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2768-2774
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• 2011

In this paper, we investigate the methods to improve the position accuracy using DGNSS(Differential Global Navigation Satellite System). Then we configure the real-time DGNSS environment with use of GPS and MSAS as SBAS(Satellite Based Augmentation System) currently being in service by Japan. And we verify the improvement of position accuracy and the continuity of GPS correction data through the realtime DGNSS test in Joongang line, Kyungbu line, Honam line.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.93-100
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• 2002

In this paper, new simple model is developed to evaluate the variation of the magnitude and the phase contrast of force components with the development of excess pore pressure in backfill soil. Also, Newmark sliding block analysis is performed inputting the calculated total force from new model. The applicability of new simple model and Newmark sliding block model is verified from the analyses of 1g shaking table test results.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.651-653
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• 2003

As a result of the project 'Development of core technology for open LBS', we developed several solutions such as personal navigation system, mobile game, and emergency system. In this paper, we explain the approach and architecture of these solutions and consider their meaning on spatial information bases and expectation in the future computing environments. The final goal of this suggested solution is to test the efficiency of our open LBS system and verify the applicability and usability in real application environments. Our approaches will be headed to the future ubiquitous computing environments.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.117-120
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• 1991

Cracks of concrete structure must be analyzed and estimated synthetically in order to have a maintenance and to insure the safety and the durability of structure. Concrete cracks have to be surveyed with respect to depth, width, shape and direction etc, but crack depth among these items is not measured easily. Occasionally, it needs to measure the crack depth of concrete structure for the purpose of evaulating the safe capacity and the necessity of repair. Therefore, this research is performed to verify the applicability and the accuracy of Ultra-sonic Pulse Velocity Technique(Tester), in non-destructive testing methods of concrete crack depth.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.745-748
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• 1996

Korea Composite Stock Price Index (KOSPI) was predicted using Cascade Correlation Network (CCN) model. CCN was suggested, by Fahlman and Lebiere [1990], to overcome the limitations of backpropagation algorithm such as step size problem and moving target problem. To test the applicability of CCN as a function approximator to the stock price movements, CCN was used as a tool for univariate time series analysis. The fitting and forecasting performance fo CCN on the KOSPI was compared with those of Multi-Layer Perceptron (MLP).

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.111-114
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• 2001

This study is a fundamental research for recycling waste vinyl in asphalt concrete mixture for roadway pavement. The mixing method and proper content of waste polyethylene(PE) film were determined through preliminary mix design. This study used 2-type aggregate gradations and two-type waste PE films. The mixtures were applied for a test pavement on a rural road. Quality evaluation of the asphalt concrete confirmed that waste vinyl asphalt concrete was applicable to road pavement.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.6
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• pp.77-81
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• 2009

This study was performed to evaluate applicability of patching materials for underwater dam concrete structure. Two kinds of patching materials was investigated. Laboratory experimentals were conducted by workability, compressive strength, bond strength, chloride ion penetration, abrasion resistance. Test results showed that the most performances are relatively good except chloride ion penetration.