• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.47-58
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• 2001

Evaluation of Freeway Congestion Management Using Mesoscopic Traffic Simulator A mesoscopic simulation study to measure the effects of trip generation caused by rampant expansion of residential area around the Kyungbu corridor has been conducted. Some alternatives, which seem to be judgememtally plausible and technically feasible to mitigate such congestion, have been carefully examined and evaluated by the simulation model called INTEGRATION. Alternatives are mostly network improvements. Banpo IC dedicated ramp construction (A1), Seocho IC TSM based weaving elimination (A2), dedicated local and express separation over Seocho-Yangjae segment (A3), Heonleung IC (A4) and Daewang If installations (A5), Pangyo IC improvement (A6), Baikhyun IC (A7) and Dongbaek IC installations (A8) along with Shingal-Pangyo segment capacity addition (A9). The most capital intensive ones are A9, A5, and A4 in that order. A1, A6, A7, and A8 are short in distance but they are also capital intensive and need some construction periods. The least capital driven alternatives are h2 and A3, the h2 is easier to do, but A3 needs traffic diversion scheme during construction. The A1, A7, and A8 have been identified cost effective in terms of speed increase and travel time saving. Along with these results, some limitations and future research agenda regarding simulation have also been presented.

• Journal of Computing Science and Engineering
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• v.9 no.2
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• pp.83-97
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• 2015

IEEE 802.15.4 is a global standard designed for emerging applications in low-rate wireless personal area networks (LR-WPANs). The standard provides beneficial features, such as a beacon-enabled mode and guaranteed time slots for realtime data delivery. However, how to optimally operate those features is still an open issue. For the optimal operation of the features, this paper proposes a holistic optimization method that jointly optimizes three cross-related problems: cluster-tree construction, nodes' power configuration, and duty-cycle scheduling. Our holistic optimization method provides a solution for those problems so that all the real-time packets can be delivered within their deadlines in the most energy-efficient way. Our simulation study shows that compared to existing methods, our holistic optimization can guarantee the on-time delivery of all real-time packets while significantly saving energy, consequently, significantly increasing the lifetime of the network. Furthermore, we show that our holistic optimization can be extended to take advantage of the spatial reuse of a radio frequency resource among long distance nodes and, hence, significantly increase the entire network capacity.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.63-71
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• 2014

As power consumption increases, more power utilities are required to satisfy the demand and consequently results in tremendous cost to build the utilities. Another issue in construction of power utilities to meet the peak demand is an inefficiency caused by surplus power during non-peak time. Therefore, most power company considers power demand management with time-based electricity rate policy which applies different rate over time. This paper considers an optimal machine operation problem under the time-based electricity rates. In TOC (Theory of Constraints), the production capacities of all machines are limited to one of the bottleneck machine to minimize the WIP (work in process). In the situation, other machines except the bottleneck are able to stop their operations without any throughput loss of the whole manufacturing line for saving power utility cost. To consider this problem three integer programming models are introduced. The three models include (1) line shutdown, (2) block shutdown, and (3) individual machine shutdown. We demonstrate the effectiveness of the proposed IP models through diverse experiments, by comparing with a TOC-based machine operation planning considered as a current model.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.515-520
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• 2004

Manufacturing Production System (MPS) has been widely accepted in construction area for the productivity improvement. However, the MPS does not always provide cost and time saving. It often caused more delays and increased project cost. Therefore the use of the MPS technique, systematic decision-making process is needed by reviewing various project parameters such as cost and time. This study includes extensive literature reviews and case studies on MPS. As a result, a decision-making model is proposed. The decision-making flowchart and decision-making model are developed in three steps: (1) identification and categorization of decision-making factors; (2) calculations of benefits, cost, and duration in accordance with the location and the production capacity of the factory; (3) comparisons of MPS and on-site assembly by varying the locations and sizes of the factory

• Korean Journal of Construction Engineering and Management
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• v.16 no.5
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• pp.54-64
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• 2015

The modular construction has several advantages such as high quality of product, safe work condition and short construction duration. The manufacturing planning of modular construction should consider time frame of manufacturing, transport and erection process with limited resources (e.g., modular units, transporter and workers). The manufacturing planning of multi modular construction project manages the modular construction's characteristics and diversity of projects, as a type of modular unit, modular unit quantities, and date for delivery. However, current modular manufacturing planning techniques are weak in dealing with resource interactions and each project requirement in multi modular construction project environments. Inefficient allocation of resources during multi modular construction project may cause delays and cost overruns to construction operation. In this circumstance, this research suggest a manufacturing planning model for schedule optimization of multi project of modular construction, using genetic algorithm as one of the powerful method for schedule optimization with multiple constrained resources. Comparing to the result of the existed schedule of case study, setting optimized scheduling for multi project decrease the total factory producing schedule. By using proposed optimization tool, efficient allocation of resource and saving project time is expected.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.331-335
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• 2020

In this study, through the accumulated technologies such as real-time monitoring of power consumption using power line communication (PLC) method, power control, and automatic blocking of standby power, to commercialize them, we developed the hardware design, algorithm, protocol and module along with data transmission using PLC. We conducted the study to develop advanced products. We also proposed cloud-based smart outlet products with a novel type of outlet. These products can measure the internal power consumption through the H/W modules and the modules that control the power of household appliances connected to the smart outlets and smart plugs. Subsequently, they transmit the measurements to the energy saving system server via a communication module. This system can control the terminal device connected to the Gateway (G/W) server through a mobile phone. This will allow the customer to check the power consumption of the building at any given time, to turn the terminal on/off, and to maximize the energy efficiency during the construction of new apartments or multi-family housing in an area.

• Tunnel and Underground Space
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• v.9 no.1
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• pp.20-26
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• 1999

The completion of the Bakun Diversion Tunnel is subsequently to the Main Dam construction. Therefore, the completion date is very important for the Bakun Hydroelectric Project. Generally, the tunnel lining work as a finishing phase of the tunnelling project occupies a important portion as well as an excavation and a support work of the tunnels in respect to the construction cost and period. Internal section of Bakun Diversion Tunnel is designed circular shape to reduce the roughness of the water flow with 12 meters in diameter of total length 4314.6 meters of 3 tunnels. The lining thickness is varied between 500 mm and 700 mm depending on the structural condition. From the original Tender design of the Bakun tunnels, the required quantity of steel bars was 5,985 ton designed by Reinforced Concrete (RC) through the entire tunnel linings. During the detail design stage by the consideration of the rock conditions and various load conditions, we could suggest five kinds of RC lining type including plain concrete lining type. Through the detail design modification, we could reduce the required amount of steel bars to 2,178 ton, as a half of original Bill of Quantity. Finally, this design modification give us the time and cost saving effect to catch up the construction progress in time.

• Journal of the Korea Institute of Building Construction
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• v.9 no.6
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• pp.121-129
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• 2009

The construction sites of small and medium buildings have small scale groundwork and the depth of excavation is often shallow. In this case, if the groundwork, girders, and ground slabs are built simultaneously by embedded assisting form rather than the existing conventional method to place concrete twice using the general form, we can expect to reduce the frame duration of the basement, resulting in cost savings. The existing embedded assisting form is restricted from use because there are cost problems with materials, labor costs,and with quality depending on the form's type. Therefore, this study is to provide an improved suggestion of building the groundwork, girders, and ground slabs simultaneously with Polystyrene by using the embedded assisting form. It also will compare the technique with existing methods of construction, and will verify its usefulness by evaluating each method of construction.

• Korean Journal of Construction Engineering and Management
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• v.9 no.5
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• pp.186-193
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• 2008

The SPS, Strut as a Permanent System, method is widely adopted for the main structural member in addition to temporary strut function for the shuttering of excavation work. Although the SPS method has contributed to cost saving, time reduction, enhancement of structural stability, improvement of construction environment and so on at the building construction site, it caused the problems of increase of basement height and additional work for fire protection of steel structure. The increase of basement height caused the increase of shuttering depth and excavation, and the fire protection caused the additional cost as well as the deterioration of construction environment. In order to improve the problems, this paper is to propose a modularized hybrid structural system(HSD). The detail of the system is introduced and the structural performance and constructibility are proved through the experiment and site application.

• Journal of Korean Society of Steel Construction
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• v.15 no.4 s.65
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• pp.413-422
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• 2003

Most engineers tend to rely on their intuition or existing data in formulating structural design or preliminary estimate of various conditions. Because of these variations, the artificial neural network is used as an alternative design model of the warren truss since it can handle uncertainty through the probability method. This research validated the approximate structural design model of the warren truss, with its proper parameter values of the neural network and design process falling within 10 percent torrence of the different designs that resulted between this model and the MIDAS program. The suggested model for the process was adapted for the truss design using the member section table, while time saving and efficiency are based on the allowed range of torrence.