• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.1001-1004
• /
• 2008

This study reviewed the results of utilization of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double layer bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and $10^{\circ}C$ even in case outside temperature drops $10^{\circ}C$ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than $6^{\circ}C$, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.30 no.1
• /
• pp.59-74
• /
• 2020

The web space where web applications run is the cyber information warfare of attackers and defenders due to the open HTML. In the cyber attack space, about 84% of worldwide attacks exploit vulnerabilities in web applications and software. It is very difficult to detect web vulnerability attacks with security products such as web firewalls, and high labor costs are required for security verification and assurance of web applications. Therefore, rapid vulnerability detection and response in web space by automated software is a key and effective cyber attack defense strategy. In this paper, we establish a security risk management model by intensively analyzing security threats against web applications and software, and propose a method to effectively diagnose web and application vulnerabilities. The testing results on the commercial service are analyzed to prove that our approach is more effective than the other existing methods.

• Resources Recycling
• /
• v.23 no.3
• /
• pp.3-12
• /
• 2014

This study aims at providing an economic assessment for incineration plants which recover heat during its incineration process. In this study, Life Cycle Cost(LCC) of incineration plants is performed based on each regression analysis formula for construction cost, operation cost, and heat generation in order to compare economic feasibility. The result shows that the incineration plant recovering waste heat while processing 80 tons of waste per day increases both initial investment and operation cost but this type of an incineration plant has economical predominance from the recovered waste heat over the one that does not recover heat when being operated for more than eleven years if the retrieved heat replaces the use of LNG. And its payback time reaches more than 19 years in case of selling heat and performing emission trading.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.1258-1262
• /
• 2010

현재 비점오염원의 정량화를 위하여 정부에서는 지목별 모니터링을 통하여 원단위를 산정하고 있으며, 이를 이용해 수질개선을 위한 수질오염총량관리제를 더욱 효과적으로 운영 평가하기 위한 노력을 하고 있다. 특히, 전 국토의 70% 이상을 차지하고 있는 산림에서 발생되는 유출수에 대한 특성을 파악하는 것이 중요하다. 보통 산림 유출 특성은 모니터링을 수행하여 파악하는 것이 가장 정확한 방법이지만, 지형 작물 시간 강우 패턴 등의 다양한 조건에서 모니터링을 수행하는 것이 어렵다. 또한 지점선정 장비구입 인건비 등 많은 비용이 요구되어 모델링을 통해 시 공간적으로 유출 특성을 평가하고자 하는 연구들이 활발히 진행 중이다. 본 연구는 GIS에서 WEPP 모형의 구동이 가능하게 된 GeoWEPP 모형을 이용하여 활엽수림 침엽수림 혼효림에서 강우시 발생하는 유출량을 모의하여 실측 유출량과의 비교 평가를 통해서 GeoWEPP 모형의 정확성을 평가하는데 있다. 모델 평가를 위해 $R^2$와 Nash-Sutcliffe model Efficiency (NSE)를 사용하였다. 활엽수림 지점은 2009년 총 10개의 강우 발생으로부터 유출량이 산정되었는데, $R^2$와 NSE는 각각 0.98와 0.87로 나타났다. 침엽수림 지점은 14개의 강우 발생시 산정된 유출을 이용하여 모델을 평가하였는데, $R^2$와 NSE가 각각 0.91와 0.90으로 나타났다. 혼효림 지점은 총 10개의 강우 발생시 산정된 유출을 이용하여 모델을 평가한 결과 $R^2$와 NSE가 각각 0.98와 0.94로 나타나 GeoWEPP 모델이 임상별 유출량을 잘 반영하는 것으로 나타났다. 본 연구 결과에서 보이는 바와 같이 GeoWEPP 모형이 임상별 유출특성을 매우 정확하게 예측할 수 있다고 판단된다.

• Korean Journal of Construction Engineering and Management
• /
• v.1 no.1 s.1
• /
• pp.80-86
• /
• 2000

The future costs of energy and the cost of the repair of apartment buildings are expected to rise continuously in proportion to the initial costs. Therefore it has become important for these increasing costs to be incorporated and reflected in the design of the building. Systems such as structure and services for the buildings remain constant, but a number of the walls and windows can vary and thus have a major influence on the total construction and running costs of a building. The critical factor in the apartment unit design for the optimization of life cycle cost (LCC) is the ratio of the x and y axis of the walls in the unit plan. This paper demonstrates how to achieve the optimal size and thus optimize the LCC of the building.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.1
• /
• pp.389-398
• /
• 2016

Previous domestic studies on silos have been carried out in many ways in various fields. On the other hand, research on the design and construction of the silo itself have not be conducted actively and an economical approach is rare. The present study provides basic information to determine the scale of the most economical silo, while satisfying the necessary conditions required by construction companies or design firms. The analysis was carried out with various parameters for reinforced concrete structures, including four kinds of storage material (flour, granulated quicklime, sand, and iron ore), five capacity sizes (10,000, 30,000, 50,000, 70,000, 90,000 ton), eight variants of H/D (0.5~4), and three types of concrete compressive strengths (30, 35, 40 MPa). The findings established a general rule in that a silo designed between 1 and 3 H/D with a greater concrete strength (40MPa and over) depending on the type of storage material would be the most cost-effective (more than 50% of quantity and labor savings).

• Journal of Korean Society for Geospatial Information Science
• /
• v.12 no.1 s.28
• /
• pp.79-85
• /
• 2004

The GIS(Geographic Information System) projects require big initial investment and cost of maintenance. Decision makers would not launch GIS projects unless they are convinced of the benefits of the projects. Therefore the purpose of this paper is to develop an appropriate model for GIS project evaluation. We proposed a GIS project evaluation model and summarize the steps involved in Cost-Benefit Analysis(CBA). The costs of a GIS implementation include hardware and software cost, costs of database development, training expenses, annual maintenance expenses, and other annual expenses. The benefit by using GIS has been assessed into Type I(direct benefits), Type II(indirect benefits), Type III(benefits that result from the sale of information services), Type IV(intangible benefits).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.3
• /
• pp.1109-1115
• /
• 2013

The present study attempts to build a decision making model for social enterprise investment. The proposed model includes four factors; social compatibility, growth, profitability, stability, and organizational suitability. Thirteen social enterprise investors were requested to rate the importance of each of the four factors when they make investment decisions. Financial stability (25.8%) and social compatibility(25.7%) turned out to be most important followed by profitability(17.5%) and growth(17.1%). Organizational suitability(13.9%) was least important. This study uncovered the first empirical factors for social enterprise investment decision making in the early stage of exploratory research. In practice, also provided several implications to social entrepreneurs, investors and policy makers.

• Journal of the Korean Institute of Gas
• /
• v.12 no.2
• /
• pp.110-117
• /
• 2008

The risks of the chemical facilities were estimated by the KS-RBI(Ver. 3.0) program supporting the quantitative cause analysis, and reduction method for the risks of the facilities was investigated. As a result, we could find that the risks of the facilities decrease with reducing the likelihood of failure (LOF) affected by demage mechanism, inspection number and effectiveness of inspection, and with reducing the consequence of failure (COF) affected by the ratings of the detection, isolation, and mitigation systems. Furthermore, high risks of the facilities would be decreased by reduction of the LOF and the COF simultaneously. Accordingly, the applied plant would be able to achieve the decrease of inspection and labor costs because of the decrease of consequences and inspection intervals through the reduction of risks.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.4
• /
• pp.571-581
• /
• 2008

The steel plate reinforced concrete structure(SC structure) is suggested for the reasons of the saving of construction period, the saving of manpower and the advantage of quality control. The objective of this study is to evaluate basic structural behavior of SC structure under pure shear load, and shear with axial load condition and to suggest the method of in-plane pure shear loading. From the test results, structural behaviors of SC structure under pure shear load and shear with axial load were investigated the combination of validity of pure shear loading method by using 4 hinge frames was verified.