• KIEAE Journal
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• v.11 no.2
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• pp.3-8
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• 2011

This study was carried out for analysing the relationship of environmental factors and the reduction rate of land compensation of six urban development projects near waste landfill sites located in the Seoul metropolitan area. For a close investigation, 24 variables were selected but only 4 environmental variables were identified to have high correlation to the reduction rate of compensation. These are fine particles(PM10), bad smell, the ratio of a greening zone of land and park, and the distance in straight line from the landfill site. Two variables-PM10 and bad smell-were found to have an effect on the average reduction rate of land compensation by correlation analysis. On the other hand, the ratio of a greening zone and the distance in straight line from the landfill site have been rejected for the significance test. The result of regression analysis of six models for the search of affecting variables on the reduction rate of compensation is that PM10 and bad smell have the impact ratio of more than 0.5. But the ratio of greening zone and the distance from the landfill are not significant factors, having the impact ratio of 0.025~0.045 except one model.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.529-540
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• 2018

Sand dam is a flow barrier commonly built on small or medium size sandy rivers to accumulate sand and store excess water for later use or increase the water table. The effectiveness of sand dam in increasing the water table and the amount of extractable groundwater is tested using numerical models. Two models are developed to test the hypothesis. The first model is to simulate the groundwater flow in a pseudo-natural aquifer system with the hydraulically connected river. The second model, a modified version of the first model, is constructed with a sand dam, which raises the riverbed by 2 m. In both models, the effect of groundwater abstraction is tested by varying the pumping rate. As the model results show the groundwater after the construction of the sand dam has increased significantly and the amount of extractable groundwater is also increased by many folds. Most importantly, in the second model, unlike the pseudo-natural aquifer system, the groundwater abstraction does not have a significant effect on the water table.

• Geotechnical Engineering
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• v.14 no.5
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• pp.235-247
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• 1998

The IIA(Inchon International Airport) which will function as the HUB airport in the northeast Asian region in the upcoming 21th century will be located in the reclaimed land with sand dredged in the vicinity of project area between Youngjong and Yongyu islands. The original ground is composed of soft clayey silt (ML) or silty clay (CL). The reclaimed land is classified as being SP-SM and having poor gradation of Cu<3 which resulted in the anticipation for difficulty in compaction (compaction index = 0.6~0.7). This anticipation shedded light on the necessity of performing test compactions for the thickness of 3~5meters of reclaimed land, aiming at the discovery of effective and economical compaction method. Upon the call for the test compaction performance 4 different compaction methods have been selected for trial from the research done on the international and local academic papers, past experience with compaction works, and their written materials. For the precise interparetation of test results, the ground survey and measurements have been performed. The Hydraulic Hammer Compaction has been chosen as the most optimum in accordance withe the test results.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.640-648
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• 2009

Recently the truction of coastal reclaimation work has been extensively implemented in Korea. The Sondo New City is being established on the reclaimed land from the sea, construction companies of metro construction are planing to pull-out the sheet pile for saving the construction cost. In the case of soft marine clay, it is very difficult to pull-out the sheet pile by using the hydraulic hammer difficult. Therefore, the man of the field must be aware of vibration effect to the ground and the structure. For understanding the vibration effect to the ground during subway construction, the model was formulated with 1/25 braced-cut for subway construction. Scott and Iai(1989) proposed the law of the similarity for other experimental conditions. The laboratory model test was conducted under the vibration condition of sheet pile pulling out. The settlement on the ground surface was measured during the shaking table test. The pore water pressure was also monitored in the upper, middle, and lower layers of soil. The field settlement level and the pore water pressure can be predicted by using the results of the laboratory shaking table test.

• Geomechanics and Engineering
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• v.29 no.4
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• pp.407-420
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• 2022

Embedded piles, which are typically used in Korea, are precast piles inserted into prebored ground with cement paste. Dynamic pile tests tend to underestimate the bearing capacity of embedded piles because of the undeveloped shaft resistance prior to the curing of the cement paste and the insufficient energy transferred after the curing. In this study, a resistance combination method using the base resistance before the cement paste is cured and the shaft resistance after the cement paste is cured is proposed to obtain a combined load-settlement curve from dynamic pile tests. Two pairs of embedded piles with diameters of 600 and 500 mm are installed. Each pair comprises one pile for the dynamic pile test and another pile for the static load test. The shape of the load-settlement curve obtained using the proposed method is similar to that obtained from the static load test. Thus, the resistances evaluated using the proposed method at selected settlements are similar to those obtained from the static load test. This study shows that the resistance combination method may be used effectively in dynamic pile tests to accurately evaluate the bearing capacity of embedded piles.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.6
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• pp.754-762
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• 2019

The transfer case for special truck are usually produced by only a few specialized companies. The special technical data are not unveiled. In order to complete the development successfully, it is necessary to carry out the compatibility tests such as the running test on the vehicle, which is the test condition of the military vehicle. In this research, transfer case the core-component of the '230 mm K-MLRS' has been developed with the reverse engineering and the prototype is developed through structural analysis. The transfer case developed through this research is currently used in the '230 mm K-MLRS'. The development process In this research are useful in the development of similar products.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.10
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• pp.4689-4692
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• 2016

Purpose: To study the clinical application value of ultrasound guided thyroid fine needle aspiration biopsy and thinprep cytology testing in diagnosis of thyroid disease. Methods: A total of 78 patients with thyroid nodules were enrolled, 34 males and 44 females, aged 33-64 years old with mean age of 47.6 years. All underwent thyroid module fine needle puncture after surgery to assess cell pathology and histopathological features. Results: Sufficient specimens were obtained from all of 78 patients, the cytological results of 73 cases (93.6 %) being consistent with pathological results. While 20 cases (25.6 %) were malignant tumors, 44 (56.4 %) were benign and 9 (11.5 %) were non-tumor lesions. The sensitivity of benign and malignant thyroid nodule by thyroid fine needle puncture was 90.9 %, specificity was 98.1 % and the positive predictive value was 96.3 %. Conclusions: It is demonstrated that ultrasound-guided thyroid fine needle aspiration biopsy and thinprep cytology testing have diagnostic value in clinical application for thyroid disease,showing good diagnostic coincidence rates with histopathological examination. They can thus be regarded as safe and effective for preoperative diagnosis and providing an appropriate basis for selection of surgery.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.2
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• pp.149-159
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• 2020

Cured-in-place-pipe(CIPP) is the most adopted trenchless application for sewer rehabilitation to extend the life of the existing sewer without compromising both direct construction and indirect social costs especially applied in the congested urban area. This technology is globally and domestically known to be the most suitable for partial and full deteriorated pipe structure rehabilitation in a sewer system. The typical design of CIPP requires a significant thickness of lining to support loading causing sewage flow interruption and increasing material cost. This paper presents development of a high strength glass fiber composite lining material for the CIPP application and structural test results. The test results exhibit that the new glass fiber composite lining material has 12 times of flexural strength, 6.2 times of flexural modulus, and 0.5 Creep Retention Factor. These test results can reduce lining design thickness 35% at minimum. Even though taking into consideration extra materials such as outer and inner films for actual field applications, the structural capacity of the composite material significantly increases and it reduces 20 percent or more line thickness as compared to the conventional CIPP. We expect that the newly developed CIPP lining material lowers material costs and minimizes flow capacity reduction, and fully replaceable to the conventional CIPP lining materials.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.113.4-113
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• 2001

A 24 channel L1 C/A-code GPS attitude-finding receiver is designed and implemented. The performance of developed receiver is evaluated under the various environments. The results show that the performances from land and maritime test are almost same in the calm lake. And it follows the expected performance derived from an analysis. It is expected that the developed receiver can be used in not only maritime applications but also land and air applications where the heading is required.

• Korean Journal of Remote Sensing
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• v.15 no.4
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• pp.357-365
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• 1999

The optical sensors of Electro-Optical Camera (EOC) and Ocean Scanning Multi-spectral Imager (OSMI) aboard the KOrea Multi-Purpose SATellite (KOMPSAT) will be placed in a sun synchronous orbit in late 1999. The EOC and OSMI sensors are expected to produce the land mapping imagery of Korean territory and the ocean color imagery of world oceans, respectively. Utilization of the EOC and OSMI data would encompass the various fields of science and technology such as land mapping, land use and development, flood monitoring, biological oceanography, fishery, and environmental monitoring. Readiness of data support for user community is thus essential to the success of the KOMPSAT program. As a part of testing such readiness prior to the KOMPSAT launch, we have performed the preliminary acceptance test for the KOMPSAT data processing system using the simulated EOC and OSMI data sets. The purpose of this paper is to demonstrate the readiness of the KOMPSAT data processing system, and to help data users understand how the KOMPSAT EOC and OSMI data are processed, archived, and provided. Test results demonstrate that all requirements described in the data processing specification have been met, and that the image integrity is maintained for all products. It is however noted that since the product accuracy is limited by the simulated sensor data, any quantitative assessment of image products can not be made until actual KOMPSAT images will be acquired.