• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.255-259
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• 2009

1997년 하수종말처리장의 민간위탁을 시작으로 국내 수도산업의 효율화에 대한 논의는 정부부처와 전문기관, 학계 등을 중심으로 제시되어 왔다. 수도산업 구조개편 논의는 지방상수도와 하수도산업의 규모의 영세성을 극복하기 위한 수직적 수평적 통합, 지방자치단체의 직영으로 인한 비효율성 제거를 위한 경영형태의 변화 등 크게 두 가지 흐름으로 정리할 수 있다. 상 하수도 사업의 수직적 수평적 통합은 주로 164개 수도사업자를 대략 9개 또는 12개 대규모 권역, 26개 또는 31개 중규모 권역으로 통합하는 방안들이 논의되고 있는데, 이와 같은 광역화 방안에 대해서는 정부부처, 연구기관, 전문가그룹 등에서 전반적인 합의가 형성되고 있다. 하지만 경영형태의 변화는 공사화와 민영화가 가장 큰 논의의 흐름으로, 이에 대해서는 집단과 지역 등 이해관계자간 상이한 견해들로 사회적인 합의를 이루지 못하고 있다. 한편 선진 수도사업을 구축하고 있는 프랑스, 네덜란드, 이스라엘 등지 에서는 수도산업의 효율성뿐만 아니라 공공성 제고 관점에서 구조적인 변화를 꾀하고 있다. 프랑스 파리시는 과거 150여 년 동안 유지되어 오던 수도사업의 민간운영을 전문공기업에 의한 위탁운영 방식으로 전환하는가 하면, 이스라엘은 정부와 민간기업간의 역할 분리를 통하여 물산업 수출국가로 발전하였다. 또한 네덜란드에서는 민영화 도입을 둘러싼 사회적 역량을 보다 발전적인 방향으로 유도하고자 법률로써 민영화를 금지하였다. 이에 본 연구는 글로벌 수도산업의 구조적인 변화 등을 살펴봄으로써 국내 수도산업이 효율성과 공공성을 제고하기 위한 경영 개선에 앞서 고려되어야 할 선결과제를 다음과 같이 제시한다. 첫째, 본 연구에서 살펴본 글로벌 수도산업의 구조적 변화(민영화에서 전문공기업화)는 수도사업의 정보의 비대칭성 및 투자저하가 효율적인 규제 메커니즘 부재에서 비롯되었다는 인식에서 추진되었다. 반면 국내시장은 산업 경제 전반이 정부주도로 이루어짐에 따라 적절한 규제의 틀과 문화가 정착되어 있지 않을 뿐만아니라 규제를 위한 전문인력도 상당히 부록한 실정이다. 따라서 효과적인 민영화의 도입을 위해서는 인적 제도적 인프라 형성이 선결과제이다. 둘째, 신규 또는 개량 투자에 대한 수요 발생, 생산원가에 미달하는 요금회수율 등은 민영화 도입 이후요금인상의 압박요인으로 작용할 것이다. 따라서 생산원가를 저감시키기 위한 광역화, 통합관리체계 등에 의한 원가절감 노력을 통하여 수도산업을 효율화하고 요금회수율을 현실화 등의 과제가 선결되어야 할 것이다.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.117-123
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• 2005

An in-hole seismic tests, which has been developed for measuring dynamic properties of soils and rock mass, is a bore hole seismic method that has cost effectiveness and practicality. The upgraded features include the motorized triggering system rather than the manual prototype version in the previous studies and a damper between source and receiver in the module. The performance of the probe has been verified through extensive cross-hole tests and in-hole tests at various sites. The dynamic stiffness of subsurface materials and rock mass have been evaluated and recently, the measurement of shear wave velocity was successfully adopted at horizontal holes of tunnel-face to install explosives. So the application of in-hole seismic test for various soil materials was certified.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.497-503
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• 2016

The cement grouting by vibration method (CGVM), a new construction technology developed in Korea, aims to efficiently reinforce a target ground area by injecting vibrated grout into it. The present study applies the CGVM to test sites and verifies its effect. Standard penetration tests (SPTs), field permeability tests, and geophysical surveys were conducted in two study areas, and the results were compared between before and after CGVM application. The SPT conducted before and after the CGVM application showed that the N value was increased by 33.57% point to 60.90% point. The field permeability test showed that the permeability coefficient decreased. These results indicate that CGVM may increase imperviousness and improve reservoir system stability. In addition, a resistivity survey found no low-resistivity zone, unlike before the CGVM application, thereby indicating the excellent grouting effect of the CGVM.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.381-388
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• 2016

Biopolishing using cellulases was introduced in the production of cotton fabric in order to improve the quality of fabric environmental friendly and is commonly used in the textile industry. In this study, the application of a crude cellulase from Acanthophysium sp. KMF001, which was excellent for the saccharification of cellulose, on biopolishing was evaluated. The optimum treatment biopolishing condition was at $50^{\circ}C$ and pH 4.5 for 60 minutes with 10% crude cellulase of fabric weight. After the optimized biopolishing, the crude cellulase of Acanthophysium sp. KMF001 reduced the tensile strength of the tested cotton fabric less than a commercial cellulase. The appearance of the cotton fabric after the treatment of the crude cellulase of Acanthophysium sp. KMF001 was similar to the fabric after a commercial cellulase treatment. All these results support that the crude cellulase of Acanthophysium sp. KMF001 was a good biopolishing cellulase.

• Journal of the Korean Geotechnical Society
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• v.36 no.1
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• pp.17-28
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• 2020

This study presents the experimental results of ground improvement efficiency induced by enzyme-induced carbonate precipitation (EICP) in soils. First, the optimal mixture ratio of EICP solution was determined by comparing the amount of induced carbonate depending on the different ratio among urea, CaCl₂, and urease. Next, we evaluated the shear stiffness and strength of EICP-treated sandy soil by performing shear wave velocity measurement and triaxial shear test. Furthermore, induced carbonate in treated soil was visually investigated by X-ray CT and SEM analysis. The results showed that the maximum shear stiffness evolved 19~30 times after 6 hours of reaction time compared with non-treated sands. Also, the cohesion and the friction angle tended to increase and decrease, respectively, as the amount of induced carbonate increased.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.227-234
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• 2000

Soilcrete has been a traditional material for pavement and soft ground improvement techniques. However, since the durability is not excellent and the quality is not consistent, it has not been used for various purposes up to date. However, with the increase of naturally oriented needs for light traffic roads such as pedestrian roads of garden, golf courses and sidewalks, the cases of the high strength soilcrete paving have been increased lately. This study aims at making a reference table of mix design in accordance with the required design specifications fur the high strength soilcrete admixtured with the pozzolanic cement by using a statistical experimental method. The treated soil is the clay which is widely found in Korea. As the results of this study, we could derive an effective reference mix design table for the clay treated with the pozzolanic cement stabilizer in accordance with the compressive strength of $50~150kg/cm^2$ soilcrete.

• Journal of the Korean Geotechnical Society
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• v.27 no.6
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• pp.27-37
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• 2011

Recently, pressure grouting is widely being used in construction site for strength improvement of ground and water proof, reinforcement and so on. It is necessarily required to estimate an appropriate injection pressure and injection time for economical and reasonable construction in the site through the size and shape of the hardened grout measured according to ground condition. However, sampling for the hardened grout is time-consuming and needs high cost on preliminary test in the site. The system which could predict the size and shape of the hardened grout does not exist until now. Thus, numerical method based on VOF method and porous model was used for the calibration chamber injection test with injection pressure (50 kPa, 100 kPa, 150 kPa) in this study. The results indicate that the numerical technique based on VOF method and porous model among CFD analysis is expected to be a basic study for the prediction of the behavior and solidification of pressure grouting.

• Journal of the Korean Geotechnical Society
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• v.28 no.2
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• pp.43-55
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• 2012

In this study, the resistance bias factors are calculated to determine the resistance factor of Gravel Compaction Piles which is one of the soft ground improvement methods. In order to calculate resistance bias factors for gravel compaction piles, two ultimate bearing capacities were analyzed. One is the ultimate bearing capacity in 2.54 cm settlement measured using data of the field loading test on 41 piles and the other is the ultimate bearing capacity calculated using the seven equations concerning bulging failure. The results of analysis show that the probability density function of the calculated ultimate bearing capacities has a lognormal distribution. Resistance bias factor and the coefficient of variation for Greenwood equation are 0.91 and 0.38, respectively, and for those of Hughes & Withers are 1.19 and 0.39. The two equations are suitable for calculating resistance factors for LRFD of soil improvement using gravel compaction piles.

• KSBB Journal
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• v.16 no.6
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• pp.527-532
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• 2001

Trichlooethylene (TCE) has become a widespread contaminant in air, soil, and underground water due to extensive industrial used and improper disposals. Since TCE is a suspected carcinogen and constitutes public health concerns, many treatment systems have been investigated to remove this hazardous waste. One of the most premising reactor systems for the treatment of TCE is trickling biofilter (TBF), in which monooxygenase (MO), the corresponding enzyme for initiating primary substrate oxidation, fortuitously degrades TCE via cometabolism. TCE, however, is not easily treated by simple TBF. This is mainly due to the toxicities of TCE and its degradation products to microbial film in TBF. In this paper, recent progresses on the development of bioreactor system for the treatment of TCE, especially gas-phase TCE, are reviewed. The potentials of novel biofilm reactor systems were also discussed for the long-term continuous treatment of TCE.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.3
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• pp.12-17
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• 2011

In this paper, we report on the improved electrical and optical characteristics for decreasing current crowding effect and uniform current distribution by designing octagonal finger type electrode pattern in large-scale lateral GaN (Gallium Nitride) LED (Light-emitting diode) with numerical 3-D simulator. Compared with the conventional electrode pattern, proposed electrode pattern was investigated to confirm the improvement of characteristics. From the simulation results of 3-D SpeCLED/RATRO simulator, we found that the forward voltage was decreased by 0.34 V and the light output power was improved by 7.72 mW at the same injection current condition in the LED with proposed octagonal finger type electrode.