• Smart Structures and Systems
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• v.30 no.2
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• pp.209-219
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• 2022

The determination for bearing capacity of precast nodular piles is conventionally time-consuming and high-cost by using numerous experiments and empirical methods. This study proposes an intelligent method to evaluate the bearing capacity and shaft resistance of the nodular piles with high efficiency based on long short-term memory (LSTM) approach. A series of field tests are first designed to measure the axial force, shaft resistance and displacement of the combined nodular piles under different loadings, in comparison with the single pre-stressed high-strength concrete piles. The test results confirm that the combined nodular piles could provide larger ultimate bearing capacity (more than 100%) than the single pre-stressed high-strength concrete piles. Both the LSTM-based method and empirical methods are used to calculate the shift resistance of the combined nodular piles. The results show that the LSTM-based method has a high-precision estimation on shaft resistance, not only for the ultimate load but also for the working load.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.5
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• pp.81-91
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• 2016

The study shows solutions of long-term unexecuted urban park and activation plans to facilitate the business promotion of Private Park Developers. This study conducted a feasibility analysis to determine if the business of a special case is applicable. The result of this study is as follows about three long-term unexecuted urban parks in Gwangju Metropolitan City's City Park. First, the three long-term unexecuted urban parks in Gwangju Metropolitan City's City Park are the forest type Neighborhood Parks. Businesses of a special case's park developing cost(average 0.4%) have a relatively low percentage. It is most affected by Land Compensation(average 33.8%) and building construction expenses(average 59.1%). Second, long-term unexecuted urban parks' Land Compensation and building construction expenses seed capital are excessive. The Bongsan Park balance floor space index is 179 percent; a reasonable profit floor space index is 220 percent. The Mareuk Park balance floor space index is 351 percent; a reasonable profit floor space index is 420 percent. The Jungoe Park balance floor space index is 327 percent; a reasonable profit floor space index is 400 percent. Third, to facilitate the business of special cases in deliberating, Bongsan Park should change its second class general residential area. Jungoe Park must change the quasi-residential area and semi-residential area. Mareuk Park must change the general commercial area. In this way, the feasibility of promoting private park projects will be improved.

• Journal of Animal Environmental Science
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• v.17 no.sup
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• pp.61-68
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• 2011

To assess the total cost with all stages of facilities, the feasibility of Life Cycle Cost (LCC) analysis was examined in this study to estimate the livestock manure treatment system and optimal decision making process. For the economic evaluation, the plant/equipment investment and annual operation cost of four Public Livestock Recycling Facilities, whose treatment capacity is 100 ton piggery manure per day, was compared. The initial cost was in the range of 2,699 million won to 3,202 million won, where T and E methods were highest and lowest, respectively. The annual operation cost was in the level of 378 million to 498 million won, which decreased in the following order : T method > J method > E method > B method. For the LCC analysis, 4.7% of interest rate, 3.13% of inflation rate, and 1.52% of net discount rate was considered by the data received from Bank of Korea and Statics Korea in the period of 2000 to 2009. Also, for the calculation of present value factor, the durable years of civil engineering & construction, machinery and electric instrument was 30 years, 10 years and 15 years, respectively. Based on these consideration, operation cost was in the range of 17,570 won/ton to 20,661 won/ton, and E method (17,570 won/ton) was economical and B method (20,661 won/ton) was non-economical. Though initial cost of T method was higher than that of B method, LCC analysis of T method was lower than that of T method due to the lower operation cost. Therefore, LCC analysis, which considers both initial cost and operation cost, is more reasonable evaluation method than either initial cost or annual operation cost. For the change of LCC analysis according to the uncertainty, the sensitivity analysis was carried out using fluctuation magnitude of discount rate in the period of 2000 to 2009. As a result, LCC analysis evaluated by discount rate was stable for the uncertain factors since the cost leadership did not change even though the sensitivity analysis varied. In summary, the economic evaluation using LCC analysis could be an efficient reference to choose the suitable livestock manure treatment plants. Furthermore, standardization of statement calculation for the actual cost analysis should be conducted and more detailed study is necessary to validate this summary. Therefore, the application of comprehensive technology evaluation, which considers LCC analysis, should contribute in obtaining objectivity and enhancing reliability for the 'Evaluation of Livestock Manure Treatment System and its Technology'.

• Journal of Energy Engineering
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• v.22 no.4
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• pp.386-393
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• 2013

An feasibility analysis is performed for the tidal current power generation with the examination of the sea water speed distribution at Pungdo. In this analysis, the water speed distribution which is the key issue was obtained from the actual speed distribution data and results in "the annual current tidal power". Due to the lack of cost information, we applied EPRI data from the internet site instead of the actual information. The result could be used as a base data for the construction of current tidal power plant in the near future. And it is expected to provides good data for the Energy policy.

• Journal of Ocean Engineering and Technology
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• v.34 no.3
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• pp.208-216
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• 2020

The Integrated Offshore Standard Specification (IOSS) involves Korean shipyards, classification societies, research institutes, the Korean industrial society, engineering companies, and oil companies with the objective of reducing costs and risks without compromising safety in international offshore engineering procurement construction (EPC) projects using new standardized bulk components and qualification procedures. The activities of the IOSS include the analysis of the existing rules and regulations to achieve the best standardization, which is reflected in the best practices, and minimize the variables in regulations and rules. In addition, a standard inventory of shapes and dimensions, referred to as specifications, is proposed in the IOSS. In this paper, the aluminum tertiary standardization part (IOSS S102-1/2 S104: Specification for Structural Tertiary Design) is presented with the details of the procedures, background reviews, and cost-benefit analyses of the design and verification methods for standard designs in the IOSS standardization items. Based on the cost-benefit analysis, the application of standardized aluminum tertiary items to offshore projects has significant advantages in terms of maintenance and repair compared to the carbon steel tertiary items utilized in current industrial practices.

• Journal of Ocean Engineering and Technology
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• v.20 no.6 s.73
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• pp.108-113
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• 2006

For the past scores of years, our country has driven its land development toward economic growth as its top priority. ut, as a result that almost all developments been promoted excepting environmental values, in fact, they've incurred some bad environmental effects desirable. Especially, as representative examples, we can raise some issues such as damages of the foreshore or coast wet lands by seas reclamation, and coast corrosion by building up of rivers or coast constructions. Recently, many people started to have great interests in businesses of environment preservation or recycling to minimize effects of these environmental matters. However, before beginning public businesses of non-commercial goods relevant to the seas environments, there seemed to be some limitations that can not accomplish under consideration of environmental sides at the same time while performing economic validities and efficiencies with environmental economic analysis, which is already effective in countries advanced in environment, it's a very meaningful course in that citizens' opinions are being influenced in seas environmental policies for their efficient execution. In this research, after modeling coast corrosion preventives with Jeong-am coast of Gangwon Province, and using Contingent Valuation Method being widely used of value measuring methods on Non-commercial goods, we've appreciated environmental economy's validity of construction works and the scale of environmental economic value of beach restoration work.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.229-238
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• 2013

This study was conducted to analyze on the operational cost of logging operations in the whole-tree logging operation system by tower-yarder and swing-yarder, and in the cut-to-length logging operation system by excavator with grapple in order to spread efficient logging operation technique and to establish the logging operation system. In the results of the analysis of operation cost, in case of the whole-tree logging operation system, the operation cost was 2,099 won/$m^3$ in felling by chain saw, 28,286 won/$m^3$ in yarding by tower-yarder, 18,265 won/$m^3$ in yarding by swing-yarder, 18,939 won/$m^3$ in bucking by excavator with grapple and chain saw, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle. In case of the cut-to-length logging operation system, the operation cost was 10,160 won/$m^3$ in felling and bucking by chain saw, 7,567 won/$m^3$ in cut-to-length extraction by excavator with grapple, 6,982 won/$m^3$ in branches and leaves extraction by excavator with grapple, 3,040 won/$m^3$ in the operation road construction by excavator with grapple, 20,484 won/$m^3$ in forwarding and accumulation by wheel type mini-forwarder, 12,701 won/$m^3$ in forwarding and accumulation by excavator with grapple and small forwarding vehicle.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.285-295
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• 2016

The post-evaluation system after construction projects can evaluate estimates of use demand, project cost, and project schedule estimated in the planning phase of construction projects in public sector. Thus, it was introduced in 2000 for the purpose of reduction in future errors during similar constructions by project orderer by referring the post-evaluation results. However, many barriers to the post-evaluation system after construction projects have been reported due to evaluation systems that lack objectivity and reliability and lack of main bodies that utilize the system. Thus, this study derived implications for improvements of the post-evaluation system in Korea by benchmarking building project evaluation system and management as well as utilization systems of developed nations. Then this study conducted a survey with experts who have experienced activities in the post-evaluation committee and members of post-evaluation for public project owners. Therefore it identified the need of installation of specialized post-evaluation institutions as well as functions and work tasks to be taken by specialized institutions. Based on the analysis results, this paper provided revision drafts of related legislations and guidelines to be effective in post-evaluation. Through the study results, many trial and errors can be reduced in similar projects in the future by performing in-depth analysis on large-scale construction projects and repeatedly applied building project practices can be improved to raise technical competitiveness if the specialized institution is installed.

• Journal of the Korea Institute of Building Construction
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• v.13 no.3
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• pp.272-281
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• 2013

Concrete filled tube (CFT) columns, which consist of a steel tube filled with concrete, combine the benefits of the two materials. The steel tube provides a confining pressure to the concrete, while the local buckling of steel plate can be prevented by the concrete core. CFT columns also have a high fire resistance due to the heat storage effect of concrete under fire. For this reason, it is possible to develop CFT columns without fire protection measures. CFT columns without fire protection have many advantages, including quality control, cost reduction, better space efficiency and a shorter construction period. Due to these advantages, studies on the development of CFT columns without fire protection measures have been performed. However, CFT columns lose their bearing capacity under fire because the steel tube is exposed to the outside. As a result, the structure is collapsed, causing significant damage. In this research, we made a CFT column using high strength concrete (100 MPa) and high strength steel (800 MPa). We use steel fiber and nylon fiber with concrete to provide fire resistance. We perform the fresh concrete experiment and investigate the fire resistance of the CFT column (${\Box}400{\times}400{\times}15{\times}3000mm$) under loading. To investigate the effect of steel fiber on increasing fire resistance, we compare the fire resistance time according to the steel fiber. Through the test, it was found that the CFT specimen with steel fiber had better fire resistance performance than other cases.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.323-329
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• 2011

This study is to determine an optimal yacht mooring location candidate among many alternative candidates in order to obtain the maximized efficiency under the natural conditions using integer programming. To deal with marina's construction location, the optimal construction location is selected using 21 important factors analysis for 4 candidates in the Mokpo city. The development period and the initial investment cost weight are one and half times more than the others among 21 factors. The optimal spiral analysis of weighted linear model shows that the Peace Square sea area is selected as the most optimal place among 4 candidates. This proposed model has not been applied in the optimal marina's facility candidate selection problem yet. This paper will contribute to determine the most reasonable alternative. Also, this proposal model can be applied to other marina's facility candidate selection problem in other regions.