• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.66-67
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• 2016

Modular construction is attracting attention as the solution of recent problems in construction site. Such as lack of construction workforce, increasing labor costs, work delay due to extreme weather events and strengthening government regulations. However, despite the many advantages, Modular construction has not been activated dueto high construction costs compared to other construction methods. Accordingly, the object of this study is priority derivation of prefabricated house cost reduction factors and use as basic research data. For research performance, we have analyzed the blueprint and bill of quantities of a modular construction based public dormitory which was built in 2013. In result, the proportion of modular construction and on-site construction is 66% and 34%, and the construction cost proportion by activity was devided in to construction(79%), machinery(7%), electricity(5%) and civil(9%). Among these results in order to reduce costs, interior finishing(19.4) steel-frame(16.9%), metal works(13.5%), RC(11.8%), joinery(7.3%) is the order requires focused management.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.21-24
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• 2006

This study investigates field application of flowing concrete in order to improve workability, duality and economic evaluation of concrete. Test results showed that slump of fresh concrete satisfied the target value before and after flowing concrete, and setting time indicated 3 hours difference depending on the mixture proportion of ready-mixed-concrete company. As for the hardened concrete, compressive strength of standard curing specimens, both control and flowing concrete, presented designed value at 28 days elapse. However, the specimens curing at atmosphere decreased the value, due to the lower curing temperature, but also performed the designed value at 91 days. For the evaluation of construction fee by value engineering(V.E) concept, a flowing method declined 4.89% of concrete construction fee, which is 4.9% reduction for materials and 25% reduction for labor expenses, compared with previous construction methods.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.83-85
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• 2011

This study investigated the results of insulation heat curing method using double layer bubble sheet in concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that concrete was protected from early freezing by remaining between 7℃ and 3℃ even in case outside temperature drops -7℃ below zero until the 3d day from piling. 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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.25-28
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• 2009

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 5 and $l0^{\circ}C$ even in case outside temperature drops $-11^{\circ}C$ below zero until the 4nd day from piling. 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.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.313-323
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• 2020

Non-destructive tests are commonly used in construction industry to access the quality and strength of concrete. However, till date there is no non-destructive testing method that can be adopted to evaluate the bond condition of reinforced concrete beams. In this regard, the presented research work details the use of ultra-sonic pulse velocity test method to evaluate the bond condition of reinforced concrete beam. A detailed experimental research was conducted by testing four identical reinforced concrete beam samples. The samples were loaded in equal increments till failure and ultra-sonic pulse velocity readings were recorded along the length of the beam element. It was observed from experimentation that as the cracks developed in the sample, the ultra-sonic wave velocity reduced for the same path length. This reduction in wave velocity was used to identify the initiation, development and propagation of internal micro-cracks along the length of reinforcement. Using the developed experimental methodology, researchers were able to identify weak spots in bond along the length of the specimen. The proposed method can be adopted by engineers to access the quality of bond for steel reinforcement in beam members. This allows engineers to carryout localized repairs thereby resulting in reduction of time, cost and labor needed for strengthening. Furthermore, the methodology to apply the proposed technique in real-world along with various challenges associated with its application have also been highlighted.

• Journal of the Korea Safety Management & Science
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• v.24 no.2
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• pp.25-32
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• 2022

The rate of industrial accident reduction is slowing down as the attention of the Ministry of Employment and Labor and related agencies on risk assessment systems decreased. this paper focuses on weakness of legal system for the risk assessment in recent years. A survey was conducted to identify the status and condition of the risk assessment system applying on small and medium-sized manufacturing companies. A set of questionnaires is designed to reflect various perspectives of the companies regarding the problems and solutions of the system. The results refer that differentiated instructions and support systems in response to the actual conditions of the companies are mandatory to reinforce the efficiency of risk assessment system.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1608-1614
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• 2009

In recent days, the study of urban regeneration has been conducting with purposeful and sincere intent starting out with the residential environment improvement works. Within the range of urban regeneration, the low-cost housing technology means development of totally-integrated housing technology that may be applied to the regeneration project, especially for the rundown areas where infrastructure facilities in the urban zone have been degraded and obsoleted. In line with this, among many and varied methods in order for realization of the low-cost housing as a part of urban regeneration project, this study should like to propose an improvement methods of the key technologies in relation to the construction works by type of work with which construction costs (directing cost) would be reduced. And, in order to elicit the method for element technology that has been developed and improved in the most optimal manner centering on the selected construction work by the type of work, the researcher conducted comparative review of summary of element technologies related to the construction works concerned, characteristics, and construction method thereof. In particular, the researcher investigated the expenses (construction cost and labor cost), constructions (contractibility and productivity), safety, quality of works, and the technical status in environmental aspects, and the researcher also conducted analyses and evaluations thereof.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.79-94
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• 2009

The research project was conducted to develop a paper bagging machine for grape. This technology was aimed to highly reduce a labor for paper bagging in grape and bakery. In agriculture labor and farm population has rapidly decreased since 1980 in Korea so there was so limit in labor. In particular there is highly population in women and old age at rural area and thus labor cost is so high. Therefore a labor saving technology in agricultural sector might be needed to be replaced these old age with mechanical and labor saving tool in agriculture. The following was summarized of the research results for development of a paper bagging machine for grape. 1. Development of a new paper bagging machine for grape - This machine was designed by CATIA VI2/AUTO CAD2000 programme. - A paper bagging machine was mechanically binded a paper bag of grape which should be light and small size. This machine would be designed for women and old age with convenience during bagging work at the field site. - This machine was manufactured with total weight of less than 350g. - An overage bagging operation was more than 99% at the actual field process. - A paper bagging machine was designed with cartridge type which would be easily operated between rows and grape branches under field condition. - The type of cartridge pin was designed as a C-ring type with the length of 500mm which was good for bagging both grape and bakery. - In particular this machine was developed to easily operated among vines of the grape trees. 2. Field trials of a paper bagging machine in grape - There was high in grape quality as compared to the untreated control at the application of paper bagging machine. - The efficiency of paper bagging machine was 102% which was alternative tool for the conventional. - The roll pin of paper bagging machine was good with 5.3cm in terms of bagging precision. - There was no in grape quality between the paper bagging machine and the conventional method. - Disease infection and grape break was not in difference both treatments.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.307-312
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• 1998

Recently the study on high flowing concrete which has high workability and Self-compacting is being proceeded actively in the university and corporative laboratory. There are some cases that has been applied to the field. This high flowing concrete has higher fluidity and segregation resistance than Plain of flowing concrete. And it is being focused as a remarkable know-how which can make high-quality concrete and reduction effect of labor force. This properties of high flowing concrete are influenced by the relationship of several factors; binder content, water binder ratio and unit water content. It is the aim of this study to propose reference data at mix design of high flowing concrete, after comparing and analyzing the fluidity and strength properties of high flowing concrete according to water binder content ratio and unit water content.

• International Journal of Contents
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• v.13 no.2
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• pp.14-20
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• 2017

The purpose of this study was to investigate the association of obesity with medical care use and costs according to overall diseases, cerebrovascular diseases (CVD), ischemic heart disease (IHD), hypertension (HTN) and diabetes mellitus (DM). The final sample was a group of persons who were free of diseases mentioned above and were not underweight. Their baseline screening program data and health insurance contribution data were connected with a 7-year medical claim database. The participants were classified according to their baseline BMI into normal, overweight, obese, and severely obese groups. Given the disease type, the total costs of DM showed the largest difference in each obesity group in both males and females. Also, the pharmacy costs for DM were more relevant than any other type of service to the obesity level. Considering the high prevalence of obesity and the relevantly increased medical care use and costs, there is a need for reduction in medical costs through obesity prevention efforts.