• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.8
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• pp.3201-3223
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• 2020

Wireless communication has become the promising technology in the recent times because of its applications in Internet of Things( IoT) devices. The IEEE 802.15.4e has become the key technology for IoT devices which utilizes the Time-Slotted Channel Hopping (TSCH) networks for the communication between the devices. In this paper, we develop a Two Level Scheduling Algorithm (TLSA) for scheduling multiple packets with different arrival rate at the source nodes in a TSCH networks based on the link activated by a centralized scheduler. TLSA is developed by considering three types of links in a network such as link i with packets arrival type 1, link j with packets arrival type 2, link k with packets arrival type 3. For the data packets arrival, two stages in a network is considered.At the first stage, the packets are considered to be of higher priority.At the second stage, the packets are considered to be of lower priority.We introduce level 1 schedule for the packets at stage 1 and level 2 schedule for the packets at stage 2 respectively. Finally, the TLSA is validated with the two different energy functions i.e., y = e^ax - 1 and y = 0.5x² using MATLAB 2017a software for the computation of average and worst ratios of the two levels.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.213-217
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• 2009

Weather factors affect cost increases and progress management under construction. Because progress schedule is delayed by weather factors, the construction costs are increased. It is an essential element to control the progress schedule applying weather factors to the progress management. This study applies monthly working-day percentages which is estimated by databases of past weather information to RTPM system. Through do progress management in construction projects exactly, will try to minimize risk of process control that do that is to weather factors. Also, will compare calamity in safety supervision side that do that is to weather factors beforehand. Based on the factors and the expected impact of factors together with the weather data during the last 50 years in Seoul region gathered from Korea. Through it, calculated number of month working day of RCA's structural steel work. Studied way that apply to RTPM system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.3
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• pp.375-383
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• 2024

The size of the construction industry is increasing, and its impact on the entire national industry is also significant. However, construction cost increases, construction period delays, safety accidents, and quality problems occur during the construction process. This paper analyzed the construction cost, construction period, and change order performance for civil infrastructures for which post evaluation was performed. The analysis was conducted by dividing civil engineering facilities by type, construction nature, construction cost, contract nature, and delivery method. Planned and actual construction cost and period were compared during the planning, design, and construction process of civil engineering facilities. There is a possibility of input errors in project performance data, this paper proposes to the post-evaluation center should perform post-evaluation. Also, post-evaluation implementation guidelines for change orders should be revised. Additionally, further analysis of each facility was proposed through continuous data collection.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1170-1177
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• 2006

We apply VRP(Vehicle Routing Problem) to sludge collection system in this study. Sewage stores of villages are located in each village around a multipurpose dam. Sludge which is produced in sewage store of village is transported from the sewage store of village to the sewage treatment plants by the special purpose vehicle such as the tank lorry. In this paper, we propose sludge collection strategies which allocate each sewage store of village to sewage treatment plants and decide the schedule of sludge collection in order to collect sludge efficiently. The strategies aim to decrease transportation cost with deciding proposed vehicle routing and scheduling the sludge collection. When we decide route of vehicles, we consider the collection time in sewage store of village, distance between sewage store of villages and vehicle information as average velocity of vehicle, operation time of vehicle driver. We also develop the SCMS(Sludge Collection Management System) based on windows system with real data which is used in certain circumstance. And we experiment to figure out vehicle route and transportation cost throughout changing input data.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.1
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• pp.105-114
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• 2007

In this paper, we propose sludge collection strategies which allocate each sewage store of village to sewage treatment plants and decide the schedule of sludge collection in order to collect sludge efficiently. The strategies aim to decrease transportation cost with deciding proposed vehicle routing and scheduling the sludge collection. When we decide route of vehicles, we consider the collection time in sewage store of village, distance between sewage store of villages and vehicle information as average velocity of vehicle, operation time of vehicle driver. We also develop the SCMS (Sludge Collection Management System) based on windows system with real data which is used in certain circumstance. And we experiment to figure out vehicle route and transportation cost throughout changing input data.

• KIEAE Journal
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• v.16 no.1
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• pp.47-55
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• 2016

Purpose: Long-life housing causes unavoidable cost increase while providing higher durability, flexibility, and repair easiness compare to those of normal apartment. The effectiveness should be evaluated considering the level of passing mandatory Long-life housing Certification System when supplying specific size of apartment complex. Thus, it is essential to identify the estimated costs and the obtainable grade by applying the optional element technologies selectively during the design phase. This study aimed to suggest the technology influence matrix(TIM) to support decision-making of element technologies in planning stage of long-life housing. Method: The technology influence matrix was established based on the property information about applicable element technologies for long-life housing such as construction methods, interface types, cost data, and certification-related characteristics. The usefulness of TIM was verified through case study, in which TIM was applied to the exclusive housing unit and the influences from four areas of quantity, cost, certification, and schedule were identified and calculated. Result: TIMs covering four areas representing the essential planning factors were developed, and are expected to contribute to sound decision-making in planning long-life housing.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.4
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• pp.82-90
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• 2003

The Systems Engineering, as a methodology for engineering and management of today's ever-growing complex system, is a comprehensive and iterative problem-solving process. The process centers on the analysis and management of the stakeholders' needs throughout the entire life-cycle of a system and searches for an optimized system architecture. There are many essential needs and requirements to be met when a system development task is carried out. Systems Engineering Management Plan(SEMP), as a specification for system development process, must be established to satisfy constraints and requirements of stakeholders successfully and to prevent cost overrun and schedule delay. SEMP defines technical management functions and comprehensive plans for managing and controlling the entire system development process, specialty engineering processes, etc. Especially. in the case of a large-scale complex system development program where various disciplinary engineering such as mechanical; electrical; electronics; control; telecommunication; material; civil engineering etc. must be synthesized, it Is essential to develop SEMP to ensure systematic and continuous process improvements for quality and to prevent cost/schedule overruns. This study will enable the process knowledge management on the subject of SEMP as a core systems engineering management effort, that is, definitely defining and continuously managing specification of development process about requirements, functions, and process realization of it using a computer-aided systems engineering software. The paper suggests a systematic SEMP development process and demonstrates a data model and schema for computer-aided systems engineering software, RDD-100, for use in the development and management of SEMP. These are being applied to the systems engineering technology development task for the next-generation high-speed railway systems in progress.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.209-220
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• 2023

Recently, defects that occurred during the construction of apartment houses have become a social issue. Defects in apartment houses lead to waste of resources and economic loss, causing psychological and physical damage to customers, and a decrease in reliability and financial loss to construction companies. The purpose of this study was to analyze the impact of defect occurrence according to the difference in project management level in the apartment housing construction stage, and to investigate the extent to which the project manager's experience affects the defect occurrence rate. For the empirical analysis of the study, statistical analysis was conducted using data collected from 130 actual projects. The results of the analysis showed that schedule management, cost management, and quality management had a positive effect on reducing the defect occurrence rate in the execution stage of apartment housing construction, while human resource management productivity had a negative effect. This study theoretically demonstrated the importance of project management, and in practice, showed that schedule management, cost management, and quality management should be faithfully performed in the execution stage to reduce the rate of defects after project completion. It was also suggested that hiring an experienced project manager would help reduce project defects.

• Journal of the Korean Solar Energy Society
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• v.38 no.2
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• pp.15-31
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• 2018

A program to design a small capacity wind turbine blade is proposed in this study. The program is based on a matlab GUI environment and designed to perform blade design based on the blade element momentum theory. The program is different from other simulation tools available in a point that it can analyze the side-furling power regulation mechanism and also has an algorithm to find out optimal torque schedule above the rated wind speed region. The side-furling power regulation is used for small-capacity horizontal axis wind turbines because they cannot use active pitch control due to high cost which is commonly used for large-capacity wind turbine. Also, the torque schedule above the rated wind speed region should be different from that of the large capacity wind turbines because active pitching is not used. The program developed in this study was validated with the results with FAST which is the only program that can analyze the performance of side-furled wind turbines. For the validation a commercial 10 kW wind turbine data which is available in the literature was used. From the validation, it was found that the performance prediction from the proposed simple program is close to those from FAST. It was also found that the optimal torque scheduling from the proposed program was found to increase the turbine power substantially. Further experimental validation will be performed as a future work.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.160-161
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• 2013

Progress measurement is one of key tasks for cost and schedule management in construction management. However, there has been shortage of effort to implement for automated progress measurement. This paper proposes to use a face recognition (FR) technology for automated progress measurement and management in construction sites. The FR technology can acquire detailed progress data that includes the in and out information of labors by location. The expected effectiveness of the proposed system is to provide accurate labor information for progress measurement by utilizing automated data acquisition technology (DAT) with high-speed reading face. In addition, it could be applied to real-time safety and quality management by using the camera images.