• Culinary science and hospitality research
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• v.18 no.4
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• pp.183-198
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• 2012

The purpose of this study is to determine potential effectiveness of sourdough starter powder (made of Korean wheat flour) in the quality characteristics of bread and in the substitution effect of a dough improver in bread baking. The bread containing sourdough starter powder was considered to be most suitable for making sourdough bread. As a result, SP 10 showed the best fermentation rate and the highest volume and specific volume. In sensory testing, SP 10 was most preferable among others. According to experimental comparison between optimal addition ratio of SP 10 and other sourdough starter powder products available in Korean domestic market, SI had the highest fermentation rate, highest volume and specific volume. Analysis of texture showed that SI was soft with the lowest hardness and the highest elasticity. Sensory test showed that SI was most preferable of all, and SP 10 was more preferable than BP. It was concluded that SP 10 was not less preferable in the aspect of preference at sensory test than other products. Hence, it is expected that sourdough starter powder made of Korean wheat flour will be possibly more popular and effective in replacing some portion of dough improver of baking.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.543-551
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• 2015

Quick-hardening track (QHT) is a construction method which is used to change from old ballast track to concrete track. Sufficient time for construction is important, as the construction should be done during operational breaks at night. Most of the time is spent on exchanging the ballast layer. If it is possible to apply the ballast non-exchange type of quick-hardening track, it would be more effective to reduce the construction time and costs. In this paper, pouring materials with high permeability are suggested and a construction method involving a layer separation pouring process considering the void condition is introduced in order to develop ballast non-exchange type of QHT. The separate pouring method can secure the required strength because optimized materials are poured into the upper layer and the lower layer for each void ratio condition. To ensure this process, a rheology analysis was conducted on the design of the pouring materials according to aggregate size, the aggregate distribution, the void ratio, the void size, the tortuosity and the permeability. A polymer series was used as the pouring material of the lower layer to secure the void filling capacity and for adhesion to the fine-grained layer. In addition, magnesium-phosphate ceramic (MPC) was used as the pouring material of the upper layer to secure the void-filling capacity and for adhesion of the coarse-grained layer. As a result of a mechanics test of the materials, satisfactory performance corresponding to existing quick-hardening track was noted.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.31-37
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• 2011

Only a few studies have been conducted using reduced slag as recycled material. The reduced slag in electric furnace is produced as a by-product in making a steel and a few applications of the reduced slag as expensive additives and bonding materials or as the stabilized soils was reported. The purpose of this study is to present the feasibility of the reduced slag as recycled material, especially, in a field of civil engineering. In order to achieve the purpose experiments such as SEM and XRF analysis was conducted for the reduced slag in electric furnace. Based on the results various geotechnical experiments were conducted to know engineering properties of slag-soil mixtures. Weathered soils and clay are mixed with reduced slag for various ratios. As the ratio of reduced slag to weathered soil increases, the maximum dry unit weight of the mixture decreased with increasing optimum moisture content. The results indicates that there is no effect on a reduced slag by compaction efforts. The shear strengths of the weathered soil-slag mixtures are slightly higher or similar to those of weathered soils. The permeability of the weathered soil-slag mixtures is similar to that of silty or sandy soils. Therefore, it is possible to use the mixtures as embankment or backfill materials in the fields. The unconfined strength of the mixtures of reduced slag and clay is higher than that of clay and it tends to increase with the curing time. Therefore it can be used to improve the soft ground.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2C
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• pp.99-108
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• 2006

In this study a series of bench scale test are conducted to increase the undrained shear strength of clayey soils using by Electro-kinetic injection stabilization method. The sodium silicate was injected in anode reservoir and its concentration was changed with 500, 1000, 1500, 2000, 2500mM for configuration of applicability of Electro-kinetic injection stabilization method. Also, the treatment time and electric gradient was changed to acquire the optical influence factors. For increasing the shear strength to maximum values, the calcium chloride and aluminium hydroxide, which concentration was changed with 50, 250, 500, 750, 1000mM, were added at anode reservoir for 5 days after the treatment of sodium silicate in 5 days as the 2nd additives. The test of results in determination of sodium silicate concentration show that the undrained shear strength at each point had a tendency to converge into a constant value when the concentration of sodium silicate came to 1000mM and above. The maximum shear strength increasement was 800% compared with initial value. After a series of test, the electric gradient and treatment time for application of electric fielld were 1V/cm and 6 days. In case of 2nd additives test, the concentration for maximum shear strength is 250mM in all additives and the effects of shear strength improvement was developed approximately 20~30% in comparison to addition of single injection material.

• Journal of the Korean GEO-environmental Society
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• v.13 no.7
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• pp.31-38
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• 2012

Water glass chemical grouts are primarily used in ground injection projects. Natural and Durable Stabilizer (NDS), Space Grout Rocket (SGR), and other similar materials composing of inorganic accelerating agents with ultra fine cement have been gaining popularity as ground improvement material in South Korea. However, there are questions as to grouting results and environmental issues caused by NDS grout. This study uses the injection method in mudstone embarkment to evaluate the differences in strength, permeability, and optimum injection volume through the use of uniaxial and triaxial compression tests and fish poison tests for NDS and SGR materials. After 28 days, results showed SGR and NDS to have a 50% increase in strength and 50% decrease in permeability with the proper injection rate at 50%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.955-963
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• 2019

Currently, the establishment and management of civil defense shelters are under the initiative of the government and local governments to protect the lives of citizens. In the future, there is a need for efficient civil defense shelters operation through the expansion of general shelters, including designated dedicated shelters. Therefore, it is more efficient to consider the distribution of residents and the location of access to shelters, not the quantitative operation considering only the number of residents. This study uses genetic algorithms and Huff gravity model based on census output data, building data, and road network information to understand the distribution of inhabitants more precisely than existing administrative district data. In addition, the spatial- database was used for efficient data management and fast processing, and if this study is improved, it can be used as a basis for the selection and improvement of general shelters positioning for a wider area.

• Journal of the Korean Geosynthetics Society
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• v.14 no.4
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• pp.97-104
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• 2015

When carrying out design for soft ground improvement before reclamation of dredged soil, it is very important to appropriately evaluate design parameters such as compression index and undrained strength in order to estimate optimum construction cost. In this study, consolidation and strength parameters were estimated by the samples obtained from the similar reclaimed land. Water content and compression index of dredged soil reclaimed by hydraulic fill method were quite decreased in comparison with those of in-situ conditions at Incheon site. Relationships between compression index(Cc) and water content (wn), and between undrained strength (su) and water content (wn) for dredged soil were obtained by field vane test and oedometer test, respectively. Applicability of Schmertmann correction method (compression index) for low plasticity silty soil was discussed according to comparison with designed and measured settlements.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.05a
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• pp.243-248
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• 2005

우리나라의 농업은 주곡의 지속적인 자급기반을 마련하고 이제 단순한 농사형태에서 벗어나 새로운 소득작목을 개발하고 합리적인 경영개선을 통하여 소득을 높이는 상업농시대에 접어들게 되었다. 따라서 상업농시대에는 농업도 새로운 기술을 바탕으로 질 높은 농산물을 안정적으로 생산공급할 수 있는 기술의 확보가 더욱 요구되고 있다. 최근 농산물수입개방 시대에 접어들게 되면서 우리 농산물도 국제경쟁력향상을 위한 품질향상 및 새로운 소득작물의 개발이 절실히 요구되는 시점에 와있다. 여러 지방지치단체에서 그 지방에 알맞은 소득작물을 개발하여 많은 소득을 올리고 있는 사례를 많이 볼 수 있다. 예로서 보성의 녹차, 무안의 무화과, 구례의 오이 등이 대표적인 예라고 할 수 있다. 여러 농업연구기관에서도 과학적인 토양연구로 세부정밀토양조사를 실시하고 작물재배의 부적지에 대해서는 토양개량방법을 연구하고 있으며 그에 따른 시비추천과 소득작물의 적지적작추천을 하고 있다. 국내에서도 GIS의 발전 및 RS의 발전과 더불어 친환경농업의 일환으로 정밀농업분야에 많은 관심이 집중되고 있다. 정밀농업은 농업생산기술 분야에서 아직 생소한 접근방법으로서 여기에서는 지구측위시스템(GPS)와 지리정보시스템(GIS), 원격탐사(RS)기법들이 많이 응용되고 있다. 또한 농업의 1차(식량생산)적인 목적에서 2차, 3차(소득증대 및 부가가치 증대)적인 목적으로 변화되고 있다. 각 지자체에서 그 지역에 적합한 농산물 재배를 위한 재배단지 확산방안 연구가 진행중에 있으며, 과거 토양속성인자를 가지고 재배적지 선정을 해왔으나, 본 연구에서는 GIS와 RS을 중첩하여 적지선정에 관한 최적의 시스템을 구현하였다. 이런 적지 선정을 통하여 유기농업의 실현을 도모하여 소비자의 욕구에 맞는 작물 생산 및 농촌관광단지 조성을 통해 부가가치증대 및 소득증대를 꾀함으로 농촌문제 해결에 도움이 될 것으로 기대된다. 본 연구를 통해 GIS 와 RS의 기술이 농촌분야에 더 효율적으로 적용될 것으로 기대되며, 농업기술센터를 통한 정보제공을 함으로써 대농민 서비스 및 농업기관의 위상이 제고 될 것으로 기대된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2375-2382
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• 2011

The user clustering for web navigation pattern discovery is very useful to get preference and behavior pattern of users for web pages. In addition, the information by the user clustering is very essential for web personalization or customer grouping. In this paper, an algorithm for clustering the web navigation path of users is proposed and then some special navigation patterns can be recognized by the algorithm. The proposed algorithm has two clustering phases. In the first phase, all paths are classified into k-groups on the bases of the their similarities. The initial solution obtained in the first phase is not global optimum but it gives a good and feasible initial solution for the second phase. In the second phase, the first phase solution is improved by revising the k-means algorithm. In the revised K-means algorithm, grouping the paths is performed by the hyperplane instead of the distance between a path and a group center. Experimental results show that the proposed method is more efficient.

• 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.