• Journal of the Korea Society of Computer and Information
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• v.20 no.9
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• pp.81-86
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• 2015

This paper suggests heuristic algorithm with linear time complexity to decide the normal and optimal point at minimum loss/maximum profit maximum shortest scheduling problem with additional loss cost and bonus profit cost. This algorithm computes only the earliest ending time for each node. Therefore, this algorithm can be get the critical path and project duration within O(n) time complexity and reduces the five steps of critical path method to one step. The proposed algorithm can be show the result more visually than linear programming and critical path method. For real experimental data, the proposed algorithm obtains the same solution as linear programming more quickly.

• Korean Journal of Hydrosciences
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• v.7
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• pp.61-75
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• 1996

The purpose of this study is to develop an efficient model for the least cost design of multi-site detention systems. The IDP (Incremental Dynamic Programming) model for optimal design is composed of two sub-models : hydrologic-hydraulic model and optimization model. The objective function of IDP is the sum of costs ; acquisition cost of the land, construction cost of detention basin and pumping system. Model inputs include channel characteristics, hydrologic parameters, design storm, and cost function. The model is applied to the Jung-Rang Cheon basin in Seoul, a watershed with cetention basins in multiple branching channels. The application results show that the detention system can be designed reasonably for various conditions and the model can be applied to multi-site detention system design.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.68-76
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• 2014

The accurate estimation of construction cost is important to a successful development in construction projects. In previous studies, the construction cost are estimated by statistical methods. Among the statistical methods, support vector regression (SVR) has attracted a lot of attentions because of the generalization ability in the field of cost estimation. However, despite the simplicity of the parameter to be adjusted, it is not easy to find optimal parameters. Therefore, to build an effective SVR model, SVR's parameters must be set properly without additional data handling loads. So this study proposes a novel approach, known as genetic algorithm (GA), which searches SVR's optimal parameters, then adopt the parameters to the SVR model for estimating cost in the early stage of apartment housing projects. The aim of this study is to propose a GA-SVR model and examine the feasibility in cost estimation by comparing with multiple regression analysis (MRA). The experimental results demonstrate the estimating performance based on the percentage of estimations within 25% and find it can effectively do the accurate estimation without through the trial and error process.

• Journal of Korea Spatial Information System Society
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• v.8 no.1 s.16
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• pp.107-118
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• 2006

In this paper, several network algorithms were tested to find an optimal one for telecommunication network design. Algorithms such as Dijkstra's shortest path algorithm, Ford-Bellman's shortest path algorithm, Prim's minimum spanning tree algorithm, and Kruscal's minimum spanning tree algorithm were reviewed and compared in terms of feasibility and resulted network construction cost. Then an optimal algorithm that is most suitable for telecommunication network design was selected. For more specific and quantitative analysis of the selected algorithm, it was implemented to a real telecommunication network construction site. The analyzed results showed that the suggested design method when compared with the conventional one, reduced the network construction cost considerably. The total network length estimated by the conventional method were 5267 meters while the suggested method resulted in 4807 meters. Thus the new method reduced the total network length by 8.7 percent which is equivalent to 97,469,000 Won of construction cost. Considering the frequent telecommunication network constructions, due to new urban developments in the nation, the economic benefit of the suggested telecommunication network design method will be significant. In addition to the construction cost savings, the suggested telecommunication network design procedure possesses several other economic benefits. Since the design procedure can be standardized and automatized, it can reduce the design cost itself and the skill acquirement periods required for new or inapt design crews. Further, due to the standardized and automatized design procedure, any telecommunication network design results can accessed more objectively.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.311-317
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• 2011

There is a growing concern in reducing greenhouse gas emissions all over the world. The U.K. has set 34% target reduction of emission before 2020 and 80% before 2050 compared to 1990 recently in Post Copenhagen Report on Climate Change. In practise, Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) tools have been introduced to construction industry in order to achieve this such as. However, there is clear a disconnection between costs and environmental impacts over the life cycle of a built asset when using these two tools. Besides, the changes in Information and Communication Technologies (ICTs) lead to a change in the way information is represented, in particular, information is being fed more easily and distributed more quickly to different stakeholders by the use of tool such as the Building Information Modelling (BIM), with little consideration on incorporating LCC and LCA and their maximised usage within the BIM environment. The aim of this paper is to propose the development of a model-based LCC and LCA tool in order to provide sustainable building design decisions for clients, architects and quantity surveyors, by then an optimal investment decision can be made by studying the trade-off between costs and environmental impacts. An application framework is also proposed finally as the future work that shows how the proposed model can be incorporated into the BIM environment in practise.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.809-812
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• 2007

This study suggests a methodology for organizing functions of nD CAD model which 4D object is linked with cost and resource information. And the suggested model is composed of process analysis function of plant project based on visualized scenario analysis. That is, it is possible to manage effectively not only construction schedule plan, but also resource and cost information by integrating construction management information into nD CAD object. And the suggested model can be utilized as information of a effective decision-making tool through analyzing of optimal process scenario and sharing of an analyzed information.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.494-496
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• 2013

Cost-Benefit Analysis (CBA) is a systematic optimization process that allows users to compare different alternatives and to determine if a project is a solid investment. Many state DOTs have included CBA in their pavement management systems (PMSs) to help allocate state funds for maintenance, rehabilitation, resurfacing, and reconstruction of pavements. In a typical CBA, each pavement type has an assigned weight factor which represents the level of importance of this pavement type. To conduct an accurate CBA, it is essential to select appropriate weight factors. Arbitrarily assigning weights factors to pavements can lead to biased and inaccurate funding allocation decisions. The purpose for this paper is to outline a method to develop an ideal set of weight factors that can be utilized to conduct more accurate CBA. To this end, a matrix of all possible weight factors sets was developed. CBA was conducted for each set of weight factors to obtain a population of possible optimization solutions. Then a regression analysis was performed to establish the relationship between benefit and weight factors. Finally, a multi-objective genetic algorithm was applied to select the optimal set of weight factors. The findings from this study can be used by state DOTs to strategically manage their roadway systems in a cost effective manner.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1861-1867
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• 2000

Granular activated carbon(GAC) adsorption is one of the best available technology to remove synthetic organic chemicals(SOCs) from water supplies and wastewater. In order to satisfy enviromental criteria and reduce GAC treatment cost, optimal study of reverse stratified tapered adsorber(RSTA) has been conducted. The RSTA was found to provide on increase in breakthrough time when compared to a conventional cylindrical adsorber(CA). Through the RSTA optimal experiment, optimal mean bed velocity was decided 19.10cm/min and optimal angle was decided RSTA($3.0^{\circ}$). Adsorption efficiency was increased with increasing activated carbon doses and the number of activated carbon layers.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.212-213
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• 2013

The constructability of Formwork has a importantly influence on the duration and cost in a construction project. However, the existing studies on the formwork are mainly focused on a method of construction. Although a layout planning of forms, especially, is an important factors affecting the constructability and cost, it is done by engineers empirically and intuitionally after completion of structure design. Therefore this study suggest a decision support model for optimal formwork layout model based on the rearrangement of structural members by using Genetic Algorithm to improve constructability of formwork.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1060-1067
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• 2009

The selection and operation of tower cranes at construction sites are dependent on the personal experience of engineers in charge of lifting work. It often causes to overestimate the safety factor resulting in increase of construction cost, or underestimate it resulting in disastrous accident. Therefore, selection of tower cranes needs to consider cost, safety and maximum lifting condition. This study, for resolving such problems, was intended to propose the algorithm designed for even the inexperienced person to select the optimal lifting equipment in timely manner. The algorithm presented herein is an optimization algorithm that enables automatic arrangement of tower crane and minimization of costs by analyzing such conditions as vertical height and lifting load, etc.