• International conference on construction engineering and project management
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• 2013.01a
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• pp.181-187
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• 2013

The construction market condition is getting worse because of global constructions slow down, low profit, market contraction and so on. For these reason, most construction companies depend on public construction projects which possible to protect construction fee, known as progress payment, by laws. Despite this law, problems of progress payment are constantly occurring and it has been main factors that hinder the construction cost's cash-flow in construction project. To solve this problem, many researchers suggested various solutions but most of solutions were focused on specific target as owner, general contractor, and subcontractor. So, most of solutions were insufficient consider about interaction between contractors. Because of these reasons, it was hard to reflected policy. This research aimed to use system dynamics to develop the model for the application and payment based on the regulations and papers. Also, performed a developed model's verification based on progress payment regulation's basic objectives.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.407-409
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• 2001

상용주파 자계와 인체의 건강에 대해서 과학적인 해명 목적으로 Specific Pathegen Free Room을 제작하였다. 환경 실험실의 설치조건 중 자계 노출장 치간의 Stray Field의 영향이 중요하므로 SPF Room을 배치하는 데 있어 각 자계노출장치의 Stray Field로 인한 노출장치의 자계 균일도를 예측 계산하고 그 결과를 바탕으로 최적 배치를 구하였으며 실제 자계 균일도를 측정한 결과 목표한 바와 같이 2%이내임을 확인하였다.

• Journal of the Korean Professional Engineers Association
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• v.18 no.3
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• pp.1-20
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• 1985

The traffic congestion of Seoul city has been one of the most serious problems to be settled since the advent of 1970s. As a means to mitigate traffic mess, the authority concerned launched the construction of subway line 3 and 4 in 1980. The two Subway lines slated for completion by 1985 cross each other and run north-south direction, passing through the metropolitan area of Seoul city fraught with high-rise edifices and large-scale shopping centers, and, in order to reduce blasting vibration, NATM was executed for a distance of 10 Km, instead of ASSM previously employed when subway line 1 and 2 were constructed. Tunnel blastings were implemented, preceded by classifying the rocks at construction area into five categories, namely, hard rock, semi-hard rock, weak rock weathered rock and silt and by calculating their respective specific charges through standard test blastings, by employing the pre-splitting and smooth blasting with drilling patterns of burn cut type, so as not to cause damages to surface structures. Most of explosives used were the slurry of low specific gravity and low velocity, and the firings executed by the use of milli-second detonators. Empiric formula were also formulated to check blasting vibrations, based on the vibration allowable values of West Germany standard, for the application to vulnerable construction zones. Should the two lines be placed for public service in 1985, about 40% of the total traffic population of Seoul city amounting to 15 million as of 1984 is estimated to be carried by subway with no difficulties.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.331-337
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• 2009

This paper summarizes some of approaches that could be taken for data exchange in a non-interoperable work environment and reports lessons learned from the Dongdaemun Design Plaza and Park project. Today's widespread application of building information modeling (BIM) to the construction and architectural design industries requires a change in the cooperation between business organizations and their methods of communication. In particular, the interoperability of information between interdisciplinary organizations, which use specific programs for different purposes, has become a critical issue. More than just a technical problem, it is also highly related to an organization's collaboration culture and the particulars of a specific project. This paper describes the interoperability issue that occurred during the construction documentation phase of the irregularly shaped building project, Dongdaemun Design Plaza and Park, designed by Zaha Hadid Architects and Samoo Architects and Engineers, from the perspective of the technological problem and the collaborative organizations' communications. Although the perfect compatibility of information is not possible, this paper deals with a practical approach to the interoperability issue by examining the way the end-users of computer-aided design (CAD) resolved the interoperability problems in practice.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.606-615
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• 2009

Estimating the reasonable construction-cost according to the construction phase in public construction is an important element for securing and executing a national budget efficiently. As a general rule, the predetermined cost of construction is estimated at the end of the design of the target structure. Therefore, it seems to be a considerably difficult problem to estimate the approximate cost of construction, only with its basic information of the bridge in the design planning phase and the early design stage where we can not have specific detailed-section of the target structure. In this paper, we present the calculation of construction-cost in the planning phase based on the analysis of factors affecting the cost of construction conducted in the previous study. Beside, to estimate the cost of construction in early design phase, we would like to present the calculation of construction-cost in the early design phase by executing the analysis of data collected from 61 steel box bridges. It was found from the result of study that the estimated cost of construction gained by the calculation of construction-cost in this paper reduces the error between the real cost of construction and that by the existing method of using.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2277-2284
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• 2013

In this study, a groundwater table fluctuation method is suggested to predict groundwater level by means of groundwater table fluctuation due to recharge and discharge under unsteady condition. This model analyzes groundwater variation characteristics by using reaction factor related with groundwater flow and specific yield related with recharge. For the test of this model, measured groundwater level at JD Yongdam 1 and JW Konghang for 5 years (2006-2010) were used. At JD Yongdam 1, the estimated specific yield was 0.023, and the estimated reaction factor was 0.039. At JW Konghang, the estimated specific yield was 0.009 and the estimated reaction factor was 0.028, respectively. This model can estimate recharge and saturated parameters, thus it is expected that this model would be the proper tool for checking the parameter of hydrologic model and percolation features.

• Journal of Drive and Control
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• v.20 no.4
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• pp.1-8
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• 2023

In recent years, robots have been utilized in various industries to reduce workload and enhance work efficiency. The following mobility offers users convenience by autonomously tracking specific locations and targets without the need for additional equipment such as forklifts or carts. In this paper, deep learning techniques were employed to recognize individuals and assign each of them a unique identifier to enable the recognition of a specific person even among multiple individuals. To achieve this, the distance and angle between the robot and the targeted individual are transmitted to respective controllers. Furthermore, this study explored the control methodology for mobility that tracks a specific person, utilizing Simultaneous Localization and Mapping (SLAM) and Proportional-Integral-Derivative (PID) control techniques. In the PID control method, a genetic algorithm is employed to extract the optimal gain value, subsequently evaluating PID performance through simulation. The SLAM method involves generating a map by synchronizing data from a 2D LiDAR and a depth camera using Real-Time Appearance-Based Mapping (RTAB-MAP). Experiments are conducted to compare and analyze the performance of the two control methods, visualizing the paths of both the human and the following mobility.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7340-7349
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• 2014

BIM (Building Information Model) and GIS (Geographic Information System) are applied widely to all stages (Planning - Design - Building - Maintenance) of construction. Recently, research for designing an integrated BIM/GIS platform has been conducted to determine the synergy effects. This paper reports the derivation of BIM/GIS platform application scenarios and definition of specific functions in construction planning and design phases. First, BIM/GIS application scenarios and platform functions are derived for each phase based on an analysis of business affairs. Second, SW functions, which compose platform function, are defined. In the construction planning phase, location selection and route location business affairs were analyzed. Preliminary design and detailed design business affairs were analyzed in the construction design phase. The result of this research can be used for BIM/GIS integrated platform design in the future.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.271-275
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• 2011

According to governmental policies for green growth, the increase in the traffic volume of railroad is a representative method to reduce total greenhouse gas (GHG) emitted from transport. Comprehensive assessment for the GHG emission of railroad has been studied to compare the difference of transport modes just in the operating step excluded the construction step. The purpose of this study was to evaluate GHG emissions in railroad construction sector. The targets were some construction works for civil, track, building, and electric system in A line. The GHG emission source of constructing railroad infrastructure was mainly the energy consumption of heavy equipments. As a result, the civil construction sector showed more than 96% of total GHG emissions and its specific GHG emission was 2.191 ton $CO_2e/m$. Also, the specific GHG emissions of civil construction works were of the order: earthworks > tunnels > bridges > station. In future, it will be required to calculate the overall GHG emission of railroad through life cycle approaches including operation, maintenance and disposal step.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.507-511
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• 2009

This paper describes the performance design requirements of the slope and soft clay structures to confirm several contents of foundations systems to change existing design code to new one in the construction market. The concepts of performance design explain systematical needs for specific performance guidelines.