• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.109-117
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• 2023

Schedule delays present a major risk factor, as they can adversely affect construction projects, such as through increasing construction costs, claims from a client, and/or a decrease in construction quality due to trims to stages to catch up on lost time. Risk management has been conducted according to the importance and priority of schedule delay risk, but quantification of risk on the depth of schedule delay tends to be inadequate due to limitations in data collection. Therefore, this research used the BERT (Bidirectional Encoder Representations from Transformers) language model to convert the contents of aconstruction log, which comprised unstructured data, into WBS (Work Breakdown Structure)-based structured data, and to form a model of classification and quantification of risk. A process was applied to eight highway construction sites, and 75 cases of rain schedule delay risk were obtained from 8 out of 39 detailed work kinds. Through a K-S test, a significant probability distribution was derived for fourkinds of work, and the risk impact was compared. The process presented in this study can be used to derive various schedule delay risks in construction projects and to quantify their depth.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.13-21
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• 2017

Airline schedules are highly dependent on various factors of uncertainties such as unfavorable weather conditions, mechanical problems, natural disaster, airport congestion, and strikes. If the schedules are not properly managed to cope with such disturbances, the operational cost and performance are severely affected by the delays, cancelations, and so forth. This is described as a disruption. When the disruption occurs, the airline requires the feasible recovery plan returning to the normal operations in a timely manner so as to minimize the cost and impact of disruptions. In this research, an Ant Colony Optimization (ACO) algorithm with re-timing strategy is developed to solve the recovery problem for both aircraft and passenger. The problem consists of creating new aircraft routes and passenger itineraries to produce a feasible schedule during a recovery period. The suggested algorithm is based on an existing ACO algorithm that aims to reflect all the downstream effects by considering the passenger recovery cost as a part of the objective function value. This algorithm is complemented by re-timing strategy to effectively manage the disrupted passengers by allowing delays even on some of undisrupted flights. The delays no more than 15 minutes are accepted, which does not influence on the on-time performance of the airlines. The suggested method is tested on the real data sets from 2009 ROADEF Challenge, and the computational results are compared with the existing ones on the same data sets. The method generates the solution for most of problem set in 10 minutes, and the result generated by re-timing strategy is discussed for its impact.

• Journal of the Korea Institute of Building Construction
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• v.21 no.4
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• pp.347-359
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• 2021

Recently, construction projects have emerged in the form of program management, which is complicated by the large-scale of construction, and requires astronomical construction costs. In particular, projects that absolutely require management at the program level, such as large-scale construction projects, require overall control of the planned schedule and cost as a set of various projects, including infrastructure. But in Korea, there is no specific management standard for delays in construction. In order to avoid the risk of cost increase and project delay in the program-level construction project, it is necessary to apply more systematic management standards to prevent delay and to take a more preemptive response in the construction process. Therefore, in this study, a delay management index (DMI) was developed to successfully carry out large-scale construction projects at the program level and prevent delays in advance. In addition, case studies were conducted for large-scale construction projects, and a delay prevention system was established for program-level construction projects.

• Korean Journal of Construction Engineering and Management
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• v.10 no.1
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• pp.36-44
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• 2009

The sum of each work duration are entire period in construction project. Each work occurs to be late, the total period of construction project will delays. Therefore, the total period of construction project will not be delayed if probability of work progress makes higher. Finding each work constraints performs constraints analysis in process of construction for checking probability of work progress. Grasp work constraints through the constraints analysis and removes. This research will show preventing delay of construction project, through work condition analysis process.

• Journal of Arbitration Studies
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• v.32 no.4
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• pp.103-141
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• 2022

Traditionally, schedule analysis in Korea has been used, mainly through the Critical Path Method, to evaluate the claim for extension of time and/or the amount of liquidated damages for delay. Critical path method, however, cannot identify the delay event and its impact occurred in non-critical path especially in multi facility projects. In multi facility projects that comprise several independent but related facilities or structures, each facility has its own facility critical path the duration of which will be impacted by facility specific critical delays. Thus, only through the non-critical delay analysis along with the critical delay analysis damages not attributable to contractors may be remedied in full. Because all the records and pictures can reveal what has actually happened in post contract review, only the retrospective analysis rather than the prospective analysis based on the assumptions can establish the cause and allocate the each parties' responsibilities appropriately.

• Korea Journal of Hospital Management
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• v.7 no.3
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• pp.44-62
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• 2002

Advanced surgical technology demands more precise, meticulous, and time-consuming procedures. In addition, the patient's preference of tertiary health providers makes over crowding of the University Hospitals. Therefore, it has been necessary to maximize utilization of the operating room of such hospitals to accommodate these requirements. This study, targeting 1,302 surgical cases performed in 22 operating rooms at a university hospital in Seoul from October 8 to November 1, 2001, analyzed reasons for delay, and factors that caused delayed use of operating rooms. This study also assessed that the rate of operating room use would increase if the sources for possible reform were improved. 1. Among total of 1,302 cases of surgery, the incidence of surgeries in which there were no time delays and no factors for delay were discovered is 71.4% or 930 cases: the incidence in which surgeries were delayed was 28.6% or 372 cases. 2. As results of logistic regression for delay, procedures involving women were delayed 1.4 times more frequently than those of men. Compared to Department A, Department B was 1.8 times more likely to be delayed, and Department H was 0.4 times less likely to be delayed. Regional anesthesia was 2.4 times more likely to be delayed than general anesthesia, and surgeries that PCA was applied were 0.6 times less likely to be delayed than those when it was not. Surgeries performed on the Thursday were 1.7 times more likely to be delayed than those performed on the Monday. Compared to surgeries performed between 07:00-07:59, those performed between 08:00-08:29 were 4.3 times higher. 3. The reasons for delay were related to surgeon, surgical department, patient, anesthesia, administrative system, sick ward, and support services. Among these, 5,755 minutes for 276 delayed cases could be resolved easily, and resolving delays of 3,320 minutes for 131 cases would be more difficult. Among the causes for delay that could be improved, delays due to patient's transfer and surgeon's factor were the most common, 21.6% and 17.4% respectively. 4. If resolvable delays are improved, pre-anesthesia room is administered, and regional anesthesia and PCA are done ahead of time, use of emergency operating rooms will increase, we can increase overall utilization by 4.09%, we will save 744 minutes a day, we can reduce the time the operation room is used after 4 PM by 35%, and we can resolve the operation cancellations due to insufficient operating rooms. For the increase in the use of operating rooms, we need to maximally decrease the delays that could be improved, by allocating block time based on used totals hours of elective cases, giving accurate information on surgery schedule, voluntary cooperation by staff participating in surgeries in reducing delay time, and the hospital management's will to improve delay.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.298-306
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• 2013

Nowadays, a transporter manager plans the schedule of the block transportation by considering the experience of the manager, the production process of the blocks and the priority of the block transportation in shipyard. The schedule planning of the block transportation should be rearranged for the reflection of the path blocking cases occurred by unexpected obstacles or delays in transportation. In this paper, the optimal block transportation path planning system is developed for rearranging the schedule of the block transportation by considering the damaged path. $A^*$ algorithm is applied to calculate the new shortest path between the departure and arrival of the blocks transported through the damaged path. In this algorithm, the first node of the damaged path is considered as the starting position of the new shortest path, and then the shortest path calculation is completed if the new shortest path is connected to the one of nodes in the original path. In addition, the data structure for the algorithm is designed. This optimal block transportation path planning system is applied to the Philippine Subic shipyard and the ability of the rapid path modification is verified.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.193-194
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• 2012

Construction work is affected by the weather; e.g. snowfall, rainfall and low-high ambient temperature, especially at a site in a severe climate. The influence of the weather is one of the possible reasons for delays in a construction schedule and quality deterioration. To protect the worksite from severe weather conditions, the temporary roof and wall could be installed on the outside of main structures designed in advance and the temporary structures could be took down after a period use. The greater coverage all-weather construction method is applied, the larger the effect. so, it is important and needs that the temporary roof and wall can be widely applied, designed to effectively about structure and layout.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.10a
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• pp.161-164
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• 2000

A cyclic shop is a production system that repeatedly produces identical sets of jobs, called minimal part sets, in the same loading and processing sequence. We consider a version of cyclic shop where the operations are processed and unloaded within time limits, so called a time window. We model the shop using an event graph model, a class of Petri nets. To represent the time window constraint, we introduce places with negative time delays. From the shop modeling graph, we develop a linear system model based on the max- plus algebra and characterize the conditions on the existence of a stable schedule.

• Journal of the Korean Professional Engineers Association
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• v.33 no.4
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• pp.44-47
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• 2000

Recently number of reinstrumentation projects in the process plants has grown to meet the needs to modernize or upgrade the exsisting control systems in a bid to boost productivity and quality. Design, installation and start-up of these process automation systems can be successful and trouble-free only if decision points are addressed properly. The critical decision points are encountered from tile design through the start-up phases of implementing a modernization project and discussed extensively here on a practical basis. Key points are ;to assign a project manager out of the plant instrument engineers for him to organize and lead a project team. ;to follow three critical steps in designing and implementing. :to think ahead of the critical steps and to induce a positive cooperation from all level of participants in the effort to prevent possible schedule delays.