• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2007.11a
• /
• pp.109-113
• /
• 2007

This paper introduces a system, Simulation based Stochastic Markup Estimation System (S2ME), for estimating optimum markup for a project. The system was designed and implemented to better represent the real world system involved in construction bidding. The findings obtained from the analysis of existing assumptions used in the previous quantitative markup estimation methods were incorporated to improve the accuracy and predictability of the S2ME. The existing methods has four categories of assumption as follows; (1) The number of competitors and who is the competitors are known, (2) A typical competitor, who is fictitious, is assumed for easy computation, (3) the ratio of bid price against cost estimate (B/C) is assumed to follow normal distribution, (4) The deterministic output obtained from the probabilistic equation of existing models is assumed to be acceptable. However, these assumptions compromise the accuracy of prediction. In practice, the bidding patterns of the bidders are randomized in competitive bidding. To complement the lack of accuracy contributed by these assumptions, bidding project was randomly selected from the pool of bidding database in the simulation experiment. The probability to win the bid in the competitive bidding was computed using the profile of the competitors appeared in the selected bidding project record. The expected profit and probability to win the bid was calculated by selecting a bidding record randomly in an iteration of the simulation experiment under the assumption that the bidding pattern retained in historical bidding DB manifest revival. The existing computation, which is handled by means of deterministic procedure, were converted into stochastic model using simulation modeling and analysis technique as follows; (1) estimating the probability distribution functions of competitors' B/C which were obtained from historical bidding DB, (2) analyzing the sensitivity against the increment of markup using normal distribution and actual probability distribution estimated by distribution fitting, (3) estimating the maximum expected profit and optimum markup range. In the case study, the best fitted probability distribution function was estimated using the historical bidding DB retaining the competitors' bidding behavior so that the reliability was improved by estimating the output obtained from simulation experiment.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.3D
• /
• pp.457-468
• /
• 2011

Recently, the non-vibration mass excavation method is used on sewage pipes and road construction sites in Jeju. However, a construction cost estimation based on the unit quantity does not provide a proper unit price. In this study, a comparison of the productivity of the standard quantity-per-unit costing method and the one of the work crew combination method was made based on the site monitoring of the non-vibration mass excavation method that is used in construction sites near Jeju. For this, data of 35 sites were collected: a regression equation was derived from the 30 data, and verification was carried out through the remaining 5 data. The analysis concluded that a day's workload is $16.43m^3$. In addition, a combination of the equipment considering the site conditions and the amount of labor, which varies with the number of work crew was obtained in order to estimate the construction cost of the work crew combination method. The construction cost was calculated based on the one-day workload ($16.43m^3$) derived from the regression analysis. The cost then was analyzed and compared with the standard quantity-per-unit costing method.

• Korean Journal of Construction Engineering and Management
• /
• v.20 no.1
• /
• pp.141-150
• /
• 2019

In the overseas plant construction market, the domain construction firms' construction capability has been greatly improved, but the capability of project management is evaluated to be insufficient compared to the technical aspect. Project management capabilities from the initial planning stage of project execution are regarded as the core competence of advanced construction companies. Among them, it is urgent to improve the capacity of conceptual estimate for domestic companies. In this study, the researchers surveyed and analyzed the methodology of estimating project cost in the planning phase of the plant project and developed an estimation method by conducting a case study analysis. Based on the logic of the cost index and parametric estimation method among the existing estimation methodology, the estimation tool was developed by deriving the input and output variables tailored to the plant project. The validity of the proposed methodology was evaluated by comparing the accuracy between the project estimate amount of the case project and the actual project amount. In order to increase the utilization of the developed conceptual estimate methodology,for plant construction project, it is necessary to systematize the data of the historical project data. Increasing the accuracy of future project cost estimates is directly related to increasing project award and profitability of the domestic construction company.

• Korean Journal of Heritage: History & Science
• /
• v.50 no.4
• /
• pp.82-103
• /
• 2017

Systems operating construction expenses for preservation and repair of the architectural heritage may be divided into two in the Japanese colonial era. They are preservation cost nd preservation cost-aided constructions, according to the ownership of a building. Preservation cost construction refers to preservation and repair of government-owned buildings that Japanese Government General of Korea had the ownership and the right of management, and preservation cost-aided construction means preservation and repair of private buildings such as Buddhist temples. In the case of preservation and repair of buildings owned by the government, it was done by the Japanese Government General of Korea, so the same agent executed the budget and managed the properties. They included royal tombs and relics, old government offices, Hyanggyo and some Seowon. On the other hand, in the case of preservation and repair of private buildings, they were private properties, so Japanese Government General of Korea had rights only for permission of preservation and repair. If there was a request for .preservation and repair by an owner, the Japanese Government General of Korea decided on whether it would support its expenses or not and played a role of management and supervision. It applied to Buddhist shrines and pagodas owned by Buddhist temples and shrines and temples owned by individuals and families. Hence, in the case of government-owned buildings, because the preservation cost was spent from the Japanese Government General of Korea's budget for investigation expenses of historical remains or repair expenses of Jeolleung and ruins, they were classified into preservation cost constructions. As for private buildings, the cost was spent from their budget for aiding preservation expenses, so they were classified into preservation cost-aided constructions. Because preservation cost construction and preservation cost-aided construction were conducted by two different agents, there were a little difference in procedures for executing a construction. There was no big difference in the general progress of constructions but was an administrative difference in the kinds of documents submitted and the roles of field supervisors. Such dual systems remained unimproved throughout the Japanese colonial era. The Japanese Government General of Korea was the colonial government so much influenced by the Japanese Government. Most Japanese architectural heritage was owned by Buddhist temples and Shinto shrines and there was almost no building owned by the government, resulting in a unitary system unlike Korea. Heritage system by the Japanese Government General of Korea was established under the influence of Japan regardless of the situation in Korea. Accordingly, Japanese Government General of Korea could not present a definite solution in the bisected system of preservation and repair expenses for the heritage. It shows the limits of the Japanese Government General of Korea in the colonial era.

• Earthquakes and Structures
• /
• v.1 no.1
• /
• pp.109-127
• /
• 2010

This work aims at introducing structural sensitivity analysis capabilities into existing commercial finite element software codes for the purpose of mapping retrofit strategies for a broad group of structures including heritage-type buildings. More specifically, the first stage sensitivity analysis is implemented for the standard deterministic environment, followed by stochastic structural sensitivity analysis defined for the probabilistic environment in a subsequent, second phase. It is believed that this new generation of software that will be released by the industrial partner will address the needs of a rapidly developing specialty within the engineering design profession, namely commercial retrofit and rehabilitation activities. In congested urban areas, these activities are carried out in reference to a certain percentage of the contemporary building stock that can no longer be demolished to give room for new construction because of economical, historical or cultural reasons. Furthermore, such analysis tools are becoming essential in reference to a new generation of national codes that spell out in detail how retrofit strategies ought to be implemented. More specifically, our work focuses on identifying the minimum-cost intervention on a given structure undergoing retrofit. Finally, an additional factor that arises in earthquake-prone regions across the world is the random nature of seismic activity that further complicates the task of determining the dynamic overstress that is being induced in the building stock and the additional demands placed on the supporting structural system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.123-130
• /
• 2002

Project plan and control is a highly skilled task which is vital for business success, and Project control systems are important for successful project execution. To support construction process management effectively, an integrated cost and schedule control function is required to collect quality data in a timely manner and to provide quality historical data for future planning of new projects. In Korea construction industry, the development and implementation cases of a project control system which to efficiently support construction project planning and controlling processes, have been increased to ensure a project success and the profitability of a construction company. To contribute to improving practical effectiveness of a project control system, the paper reviewed and analyzed the current trends and functional features of current project control systems. And it also described the pending issues and their solutions faced on previous project control systems.

• Korean Journal of Construction Engineering and Management
• /
• v.5 no.1 s.17
• /
• pp.168-174
• /
• 2004

Project plan and control is a highly skilled task which is vital for business success, and Project control systems are important for successful project execution. To support construction process management effectively, an integrated cost and schedule control function is required to collect quality data in a timely manner and to provide quality historical data for future planning of new projects. In Korea construction industry, the development and implementation cases of a project control system which to efficiently support construction project planning and controlling processes, have been increased to ensure a project success and the profitability of a construction company. To contribute to improving practical effectiveness of a project control system, the paper reviewed and analyzed the current trends and functional features of current project control systems. And it also described the pending issues and their solutions faced on previous project control systems.

• Journal of the military operations research society of Korea
• /
• v.32 no.2
• /
• pp.78-91
• /
• 2006

Recently mass customization has become a new paradigm in the global market to satisfy both the diversified demands of customers but also the efficiency of the mass production system. In this paper, mass customization is embodied by a new product development method with which various product families are produced from standard "product platform" developed from historical data. The product platform, the key concept of this proposed method, is significantly efficient as a solution to the customer demand of high variety and small quantity products. The proposed method is applied to build the platform family of naval ships, utilizing the concept of "Group Technology". In addition, cost effectiveness of the proposed method is analyzed and the applicable range of requirement conditions are presented. In conclusion, some remarkable effects such as reduction in production cost and development time are expected by employing this method to the procurement process of the naval ships.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2004.11a
• /
• pp.317-322
• /
• 2004

As a construction project in urban area tends to be high-rise and huge, the importance of the project's underground work, in terms of the cost and the schedule, is gradually increasing. It's extremely significant to choose a proper filing method, at the stage of underground work. However, in piling work many change orders have been occurred since a piling method is experientially selected based on uncertain information and many earth factors to consider. It has effects on the cost and the schedule of the project. In this study, we have suggested a decision model for piling method that can be used to determine and verify the suitable piling method in design and pre-construction phase of a project. Based on historical data, a neural network model has already proven to be efficient. The tests of the model for selecting a suitable piling method have progressed exactly with the data of 150 piling works which were done room 2000 to 2004 in Korea. The optimization or the developed neural network model has progressed with the data for teaming. The validity of the neural network model has been verified.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.12
• /
• pp.209-216
• /
• 2010

Optical Temperature Distribution Sensor Measurement System uses fiber optic sensors itself for temperature measurement is a system which can be measured the Installed surrounding entire temperature as a thousand points by laying a single strand of fiber optic. If there are a lot of measuring points in the distribution Measurement, the cost of each measuring point can be reduced the cost level of existing sensors and at the same time this has the advantage of connecting all sensors as one or two strands of fiber. Generally Optical Fiber is used for communication but Optical Fiber itself can be used for sensor and it has the characteristic of sensor function which can be measured Temperature in the at least each one meter distance. By using these characteristics each sensor and the number of Connection Lines can be reduced. In this paper, we implement a real time temperature monitoring system, which is easy to manage and control for data storage, data management, data storage using a computer and which has the functions of monitoring and correction according to Real-time temperature changes using historical temperature data.