• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.2
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• pp.97-105
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• 1984

We have, at present, found some studies on the optimum design of reinforced concrete about the simple slab but very few about the multi-story and multi-span slab. The aim of this study is to make a optimum design of coalesced beam and column slab constructure. Some results of the evaluation by using the optimalized algorithm that was developed in this study are as follows. 1. Slab was mainly restricted by the constraint of effective depth, bending moment, and minimum steel ratio; especially the effective depth was the preceding crifical constraint. In the optimum design of slab, therefore, the constraint about the minimum thickness should be surely considered. 2. This optimum design is good economy as much as some 3.4&~6.2% compared with the conventional design method. 3. In most case, it was converged by 3 to 6 iteratin regardless of the highest or lowest value and only in case of N=1 and case 1, there is a little oscillation after the 3rd iteration but it makes no difference in taking either the highest or lowest value because the range of oscillation is low as much as about 1.2% of the total construction cost. 4. In this study the result seeking for constraints that make no difference in the least cost design shows that shear stress and maximum steel ration may not be considered in it. 5. Bending moment was converged by one time iteration regardless of the initial value, while steel ratio, in most case, by two times because both bending moment and steel ratio are the fuction of effective depth.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.6
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• pp.67-72
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• 2019

This study compared the theory of a culvert spacing and analytical results of the seepage flow for the subsurface drainage. i) If culvert spacing (Sc) is within 5 m, the unit drainage (q) is very larger; in contrast, if Sc is 5 m or more, there is very little drainage in the middle between drains. Therefore, the drain spacing should be within 5 m to ensure high drainage efficiency. ii) Since the planned culvert drainage increases linearly with the soil's permeability coefficient (k), k must be taken into account when determining the drain diameter by the planned culvert drainage. iii) As a result of analyzing the drainage performance of the absorbing culvert, the drainage performance is sufficient with the diameter of the corrugated drain pipe Dc = 50 mm at the length of the drain Lc = 100 m. iv) Therefore, if the drain spacing (Sc) is less than 5 m using the low-cost non-excavated drainage pipe method (${\Phi}50mm$ the corrugated drain pipe and fiber mat) rather than the conventional trench drain method (Sc > 10 m, Dc > 100 mm), uniform and high drainage efficiency can be ensured as well as low construction cost. v) The sub-irrigation+drainage culvert requires narrower drain spacing (Sc < 2-3 m) for irrigation. As a result of examining the condition of 35 mm in diameter (Dc) and 2~3 m in drain spacing, it is possible to apply the non-excavated drainage pipe method to the sub-irrigation+drainage culvert because drainage performance is sufficient at the drain length Lc = 50 m.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.4
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• pp.15-26
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• 2019

In recent years, researchers are increasingly trying to use BIM-based 3D models for BIM nD design such as 4D (3D + Time) and 5D (4D + Cost). However, there are still many problems in efficiently using process management based on the BIM information created at each design stage. Therefore, this study proposes a method to automate 4D and 5D design support in each design stage by using BIM-based Dynamo algorithm. To do this, I implemented an algorithm that can automatically input the process information needed for 4D and 5D by using Revit's Add-in program, Dynamo. In order to support the 4D design, the algorithm was created to enable automatic process simulation by synchronizing process simulation information (Excel file) through the Navisworks program, BIM software. The algorithm was created to automatically enable process simulation. And to support the 5D design, the algorithm was developed to enable automatic extraction of the information needed for mass production from the BIM model by utilizing the dynamo algorithm. Therefore, in order to verify the 4D and 5D design support algorithms, we verified the applicability through consultation with related workers and experts. As a result, it has been demonstrated that it is possible to manage information about process information and to quickly extract information from design and design changes. In addition, BIM data can be used to manage and input the necessary process information in 4D and 5D, which is advantageous for shortening construction time and cost. This study will make it easy to improve design quality and manage design information, and will be the foundation for future building automation research.

• Journal of the Korea Organic Resources Recycling Association
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• v.7 no.1
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• pp.53-66
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• 1999

Limited landfill area and finance as well as a large generation of food wastes, have called for systematic approaches towards potential cost savings. In this study, the regional management system of food wastes generated from the residential and commercial sources was considered in three cities bounded each other; Changwon, Masan, and Jinhae city. Total thirteen alternatives were established and compared by applying the WRAP (Waste Resource Allocation Program). The following results were obtained: 1. While relatively small amounts were generated from the commercial sources such as cafeteria, restaurants, and market facilities, almost 80% of food wastes were generated from the residential sources. 2. Unit costs for food waste management in three cities were different according to their present situation such as the type and location of major generation sources and treatment facilities. Especially, the highest cost appeared in Jinhae city due to the most expensive construction of coastal landfill site. 3. Considering proper revenue, the whole conversion of food waste into animal feed was selected as the optimal alternative and represented 60% to 74% of the management cost of the whole landfill alternative in all cities. Comparing the other alternatives, composting of food waste was more economical than landfill alternative and the incineration was the most expensive alternative. 4. Some of the regional management systems using common food waste processing facilities together in three cities showed to be more economical than the single management system. Therefore, more detailed research for the regional management systems of food waste was recommended.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.7
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• pp.377-384
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• 2017

This study examined the possibility of solving the water shortage problem through the water reuse of buildings through the Suwon water reuse (greywater) facility installation project conducted as a pilot project of Ministry of Environment. Water reuse of individual building units can reduce city water demand by up to 25%. This is a level that can solve the water shortage problem in Korea. However, in order to revitalize the water reuse facilities of individual buildings, it is necessary to solve the problem of the user's rejection of the greywater and the economical problems. The resolution of the user's rejection can be solved by linking the MBR process with the AOP process. When the MBR process and the AOP process are operated in conjunction with each other, it is found that the users do not feel the water quality difference with the tap water. Economical problems can be solved at the water rate levels when the facility capacity is over 100 ton/day considering the construction cost and the operation cost, and when the operation cost alone is over 15 ton/day. Furthermore, when considering the social benefit cost, it is found that profit is generated from 150 ton/day.

• Korean small business review
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• v.42 no.3
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• pp.145-172
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• 2020

This study shows that it is favorable for Korean companies to maintain fairness and authenticity trading relationship with trading companies. It suggests that a positive reputation can be secured, trust relationships can be built, and transaction costs can be reduced. For this purpose, research hypothesis was established, questionnaires were collected for domestic companies, and a hypothesis test was conducted. As a result of the research hypothesis test, the perception of transaction fairness and the perception of transaction authenticity have a positive effect on reputation, and the reputation has a positive effect on trust. Trust has a positive effect on the reduction of transaction costs, and reputation and trust play a role in the perception of transaction fairness and transaction authenticity and the reduction of transaction cost, and trust is a parameter between reputation and reduction in transaction cost. Do it. In order for sustainable management activities to be carried out for Korean companies, it is necessary to improve fairness and authenticity in business relations. It is important to have a positive reputation. It has been demonstrated that securing a positive reputation can develop into a trust relationship and ultimately lead to a decrease in transaction costs.

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.101-111
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• 2006

The SCP girder, which compensates for the shortcomings of conventional girders through the effective composition of concrete, steel, and PS tendon, has recently been developed and applied on real bridges. Developed as a simple-support type, it may be applied on simple-support and continuous bridges by connecting the simple-support SCP girders to the interior supports. A continuous SCP girder, which has structural and cost advantages over the simple-support SCP girder, is proposed in this study. Likewise proposed herein is a new method of constructing a continuous SCP girder, using segments of the girder sequentially. A two-span, half-scale specimen was designed and constructed to verify the propriety of the continuous SCP girder bridge. A static load test was also carried out, using this specimen, to examine the behavior of the continuous SCP girder. Based on the results of the study, it is expected that the continuous bridge that uses the continuous SCP girder can guarantee the structural safety of the simple-support SCP girder.

• Korean Journal of Construction Engineering and Management
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• v.15 no.5
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• pp.147-159
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• 2014

After 2008 global financial crisis, Korean housing market has experienced stagnation. So it caused housing market problems like housing price reduction, rising rent cost and so on. For housing market normalization government announced policies but Korean housing market didn't recover from stagnation. So, to understand why Korean housing market couldn't overcome the recession and why the policies didn't be effective, this research analyzed housing market participants (home owner, housing demand) based on the law of supply and demand and the psychological effect on their transaction intention based on behavioral economics(behavioral finance). Based on the analysis this research tested the effectiveness of announced policies using System Dynamics. The result showed that the amount of transaction and mortgage loan was influenced by the length of time to draft policies.

• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.402-409
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• 2013

In metropolitan railway systems, the average commuting time keeps increasing as the scheduled speed increases, and this leads to a decline of rail service usage and competitiveness. Therefore, effective express operation for urban trains is required to improve the scheduled speed. In this study, based on the obtainable time shortening efficiency and economic viability, several express operations are suggested for urban railways and these suggestions are compared by considering high performance trains with acceleration/deceleration and maximum speed improvement. As a result, the optimum express system, which can minimize the cost for sidetrack construction, is suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1109-1117
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• 2017

Recently, 3D printer technology has been attracting attention in various industrial fields, and research papers are being conducted to utilize 3D printers in the construction industry. Actual structures such as bridges and buildings are being printed to 3D printers, and various applications such as mock-up structures using 3D printers are being proposed. In order to utilize 3D printer technology in the construction field, a 3D model is required, and the 3D BIM data produced at the design stage can be printed by a 3D printers, saving the cost and time of 3D model generation. However, 3D BIM data often does not satisfy the conditions for 3D printer output, causing many errors on output. In this paper, authors propose a problem analysis for 3D BIM model output to 3D printer and a method for reducing errors in 3D printing process of 3D BIM model. In addition, this paper presents a practical application of 3D model output from 3D printer.