• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.148-154
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• 2005

Ground-source (Geothermal) heat pump (GSHP) systems can achieve a higher coefficient of performance than conventional air-source heat pump (ASHP) systems. However, GSHP systems are not widespread in Japan because of their expensive boring costs. The authors have developed a GSHP system that employs the cast-in-place concrete pile foundations of a building as heat exchangers in order to reduce the initial boring cost. In this system, eight U-tubes are arranged around the surface of a cast-in-place concrete pile foundation. The heat exchange capability of this system, subterranean temperature changes and heat pump performance were investigated in a foil-scale experiment. As a result, the average values for heat rejection were 186${\sim}$201 W/m (for pile, 25 W/m per Pair of tubes) while cooling. The average COP of this system was 4.6 while cooling; rendering this system more effective in energy saving terms than the typical ASHP systems. The initial cost of construction per unit for heat extraction and rejection is ${\yen}$72/W for this system, whereas it is f300/W for existing standard borehole systems.

• Journal of the Korean Institute of Rural Architecture
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• v.14 no.3
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• pp.101-108
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• 2012

The purpose of this study was to set and analyze the feasibility and survey of the Hanok(The traditional Korean style house) housing complex project within Seoul metropolitan area. The results of this study were as follows. First of all, a survey was carried out to find out the optimum Hanok style. The survey showed that many people chose a frond and back yard garden as a merit of Hanok and pointed out the weak crime prevention as a weakness of Hanok. The optimum size for a Hanok was from $264m^2$ to $330m^2$ and living space was from $100m^2$ to $132m^2$. And people considered about 120% of what the apartment sells for as the reasonable price of a Hanok. Based on the survey, this study planned a Hanok housing complex on a lot that has competitive price and analysed the feasibility of the housing plan. The result was that Hanok's construction cost per $3.3m^2$ to be a marketable product has to be below about 6 million Won. As a result, the construction cost-saving through the advanced technology and planning to meet the changing customers' needs are needed to vitalize Hanok's supply.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.4
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• pp.3170-3180
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• 1973

This study of the subject will review past and present irrigation development in Korea. Particular attention will be given to water pricing structure and a case study on the purpose of rational operation and management of irrigation water and organizations, and the optimum irrigation water and organizations, and the optimum irrigation water fee inorder to reduce farmers burden and to rationalize the farmland associations management so as to achieve development of the rural environment. In 1971, the reservoir of the Farmland Improvement A sociation (FIA) produced only 775 millison $m^3$ of irrigation water or 77% of planned capacity of 1,015 million $m^3$. It was caused by inefficient maintenance of irrigation facilities; for instance, about 21% of reservoirs, pumping stations and weirs in Korea have been silted by soil erosion which hinder to water production according to an ADC survey. The first Irritation Association was established in 1906, whcih was renamed the Farmland Assoeiation by the Rural Development Enouragement Law in 1970. By the end of 1971, 411,000 ha of rice paddies were under the control of 267 associations nationwide. The average water price assessed by Associations nationwide rose from 790 won per 0.1 ha. in 1966 to 1,886 won in 1971. The annual growth rate was 20%. The highest water price in 1971 was 4,773 won her 0.1 ha. and the lowest was 437 won. This range was caused by differences in debt burden, geographic conditions and management efficiency among the Associations. In 1971, the number of Associations which exceeded the average water price of 1,886 won per 0.1 ha. was 144, or 55.1% of all Association. In determination of water price, there are two principles; one is determined by production cost such as installation cost of irrigation facilities, maintenance cost, management cost and depreciation ect. For instance, the Yong San River Development project was required 33.7 billion won for total construction and maintenance cost is 3.1 billion won for repayment, maintenance and management cost per year. The project produces 590 million $m^3$ of irrigation water annually. Accordingly, the water price per $m^3$ is 5.25 won. The other principle is determined by water value in the crop products and in compared with production of irrigated paddy and non-irrigated paddy. By using this method, water value in compared with paddy rice vs. upland rice(Average of 1967-1971) was 14.15 won per $m^3$ and irrigated paddy vs. non-irrigated paddy was 2.98 won per $m^3$. In contrast the irrigation fee in average association of 1967-1971 was 1.54 won per $m^3$. Accordingly, the current national average irrigation fee(water price) is resonable compared with its water value. In this study, it is found that the ceiling of water price in terms of water value is 2.98 won per $m^3$ or 2,530 won per 0.1 ha. However, in 1971 55% of the associations were above the average of nationwide irrigation fees. which shows the need for rationalization of the Association's management. In connection with rationalization of the Association's management, this study recommends the following matters. (1) Irrigation fee must be assessed according to the amount of water consumption taking intoaccount the farmer's ability. (2) Irrigation fee should be graded according to behefits and crop patterns. (3) Training personnel in the operation and procedures of water management to save O&M costs. (4) Insolvent farmland association should be integrated into larger, sound associations in the same GUN in order to reduce farmers' water cost. (5) The maintenance and repair of existing irrigation facilities is as important as expansion of facilities. (6) Establishment of a new Union of Farmland Association is required to promoted proper maintenance and to protect the huge investment in irrigation facilities by means of technical supervision and guidance.

• Korean Journal of Organic Agriculture
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• v.4 no.1
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• pp.45-58
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• 1995

This paper studied production characteristics of organic farming products and analyzed management income and production cost of organic farming(rice). In order to analyze these points actually, this study was focused on pruduction activities of a producers' organization, Pulmoo Cooperatives in Hong-Dong Myun, Hong-Seong Region, Chung Nam Province. So the following results were obtained : In 1994, output level and an income rate of rice per unit area(10a) which was produced in organic farming method(O.F.M) was higher than those of general farming method(G.F.M) as about 5%, 7.4%. And management income size of the former was 1.8 times as large as that of the latter. But rice production cost of O.F.M was 1.93 times as much as that of G.F.M, particularily in labor cost and farming equipment cost, light and heat expenses, many other material costs. For the progress of organic farming O.F.M and equipmets should be developed much more, for example, the technics of prevetion against damages by blight and harmful insects and improvement of varieties, natural pesticides, agricultual application of microorganisim, construction of compost heat factory, etc. Since these technics and establishments have taken on the public goods, the development of those should be supported by government.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.2
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• pp.13-18
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• 2016

Energy saving has been main concern, thus government supporting policies which are based on Fundamentals of Low-carbon Green Growth Act', 'Green Building Support Act, have been prepared in Korea. The objective of this study is to estimate energy conservation effectiveness and economic advantage assuming that lighting equipments and heat source equipments would be retrofitted. Office building, which has total floor area of $30,000m^2$, was a subject of this study. From the estimations, electric rate will be decreased by 62,886,000 won per year due to lighting equipments retrofit, and gas rate will be decreased 11,141,000 won or 17,332,000 won per year due to heat source equipments retrofit (in case of COP 1.2 or 1.5). Payback period of each case that are calculated by energy saving cost and retrofit cost are estimated 27.9 year, 38.6 year and 29.2 year, thus economic supporting policies is necessary for effective energy saving in buildings. Meanwhile payback period of heat source equipment for new building is estimated 6.1 year and 8.3 year.

• Journal of the Korea Institute of Building Construction
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• v.15 no.2
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• pp.209-215
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• 2015

This study was conducted to analyze the actual utilization rate of the deposit for defect repair of apartment complexes and its influential factors. We analyzed the data on enforced defect deposit cases by using one-sample t-test, Pearson's correlation analysis, and simple linear regression analysis. The difference between the deposit amount specified and the enforcement amount actually disbursed was found to about 0.51%. The change rates for short-term costs amounted approximately to $839KRW/m^2$ and 130,000 KRW/household per year, and those for long-term costs were $647KRW/m^2$ and 123,207 KRW/household per year. The results warrant the need for further research on establishing a deposit amount based on actual statistical data.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.167-175
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• 2011

Evaluation of fuel consumption for the various road condition and vehicle type is necessary to perform the economic analysis of road construction which is important for the efficient design and management of road. Economic analysis of road should consider the social cost which can be divided into agency cost including initial construction expense, maintenance cost, and so on, and user cost consisting of vehicle operating cost, congestion cost, etc. Since vehicle operating cost depends on the traffic volume, fuel consumption that is a major part of vehicle operating cost will change by traffic volume as well. Fuel consumption is significantly affected by vehicle speed and road condition, especially the roughness. Thus, fuel consumption should be evaluated in terms of road condition, which is not currently considered. In this study, the estimation model of fuel consumption for the passenger cars in Korea has been developed by considering the road condition. First, the relationship between vehicle speed and fuel consumption that is used to calculate the vehicle operating cost for investment evaluation of transportation facility and the initial feasibility study of road construction was investigated. Second, with the consideration of road roughness, fuel consumption of the passenger car was measured. From the measurement, it was found that fuel consumption increased by $80m{\ell}$ per 100km driving as the roughness increased by 1m/km. Therefore, it is recommended that for the economic analysis of road design and management, the fuel consumption should be a function of road roughness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7204-7210
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• 2015

This paper has developed the system for supporting the approximate construction cost and the quantity estimation based on 3D model information in the pre-project planning phase of 3-span continuous cable-bridge with 2-pylons. First of all, we'd analyzed the design information (structural design report, blueprint and quantity) of the existing cable-stayed bridges and derived the design variables of cable-stayed bridges. We developed the BIM wizard that generates a cable-stayed bridge model parametrically based on derived design variables. The principle material quantities of cable-stayed bridge are calculated directly from 3-dimensional bridge model built by using the BIM wizard. Then, we can estimate the construction cost in relation to its quantities and unit cost of cable-stayed bridge. In a result, we have established the system that the construction cost can be estimated more specific than the conventional method (construction estimates per meter or square meter). We hereby will be able to review various alternatives as soon as possible in bidding process.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.2
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• pp.47-56
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• 2015

At the present, the mechanized form roads pavement was constructed with plain concrete. Mostly, it was used by welded wire mesh for preventing crack. Cellulose fibers for the reinforcement of concrete offer relatively high levels of elastic modulus, fiber count (per unit weight), specific surface, and bond strength to cement-based materials. The construction of concrete pavement confirmed that cellulose fiber reinforced concrete was applicable to mechanized form roads pavement. In the study, cellulose fibers were used here at 0.08 % volume fraction, which is equivalent to a fiber content of $1.2kg/m^3$. Cellulose fiber reinforced concrete were compared with plain concrete. Field test results indicated that cellulose fiber reinforced concrete showed slightly to increase of 28 days compressive strength and improved the initial strength. it tended to increase of splitting tensile strength. Test results showed that the slump and air content tend to decreased. but, the variation of air contends is very little. Also, construction cost of cellulose fiber reinforced concrete is less than about 25.7 % the case of welded wire mesh previously used. Therefore, The cost reduction is expected to be possible in construction site by mechanized form roads pavement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.791-800
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• 2013

Needs for developing a better way of cost estimating process for public construction projects have been widely recognized. Those needs are mainly from the early phases of the project through the construction life cycle due to the its importance to the control process. In contrast to the traditional estimating method based on unit-price references, this research utilized this following process. The first step is analyzing the real cost data from actual cost activities (2000~2010) about the statement of P.S.C(Prestressed Concrete) Box Girder Bridge. The collected data was broken into four categories based on technical construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). The second, actual design documents including the actual cost estimating documents, drawings and specifications were carefully reviewed to cluster the cost itemized statement from four categories. It was also attempted to seek the proper breakdown of standard works that are responsible for more than 95 percentage in each categories in terms of its cost. The third, this research comes up the index for standard unit materials and unit price of standard work and develops the approximate estimating model applying for the specification(length and breadth of bridges) per square area that the user takes as well as suggests the practical application plan within the original time alloted.