• Journal of the Korean Operations Research and Management Science Society
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• v.9 no.2
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• pp.46-55
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• 1984

The purpose of this parer is to provide a survey of the state of the art of routing methods in store-and-forward computer networks. The survey is carried out in line with a new taxonomy： heuristic methods, user-optimization methods, and system-optimization methods. This taxonomy on routing algorithms is based on two viewpoints： the level of optimization and the relative difficulty for the implementation in real computer networks. Some actual methods implemented in real computer networks are surveyed as well as the theoretical studies in the literature. This paper concludes with some points in need of further researches.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.126-127
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• 2018

Rebar work is important in terms of cost and process of reinforced concrete construction along with formwork and concrete construction, and the quality of reinforced concrete construction has a great influence on the safety and durability of the structure. Therefore it is important to thoroughly inspect the steel reinforcement after casting the concrete because it is difficult to confirm the actual condition of the reinforcement. The purpose of this study is to develop an augmented reality system to visualize the records of bar placing work, which is increasingly utilized in the construction field. In order to improve maintenance of reinforced concrete, this study suggests a plan to effectively manage the drawing information including the structural drawing, the placing drawing, and the photographed image at the construction and inspection stage, and develop a system that utilizes augmented reality technology that can display the state of the inside of a concrete structure by superimposing it on actual environment.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.3
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• pp.176-183
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• 2017

In recent years, studies about multitasking becomes more important. During multitasking, operators can feel frustration when they are interrupted during the task and frustration can affect operator's emotional state and performance. However there is no research on measuring the frustration quantitatively in multitasking environment. In this paper, we suggested quantitative measurement of frustration during multitasking. In order to measure the frustration, we made a mathematical representation with emotional decay model and the initial intensity of frustration based on cognitive closure theory. The amount of initial intensity could be represented as the ratio of actual remaining time to expected remaining time. By the experiment, we measured the frustration during the experiment and compared this values with values of frustration dimension of NASA-TLX. Finally we got the linear regression model with a good accuracy ($R^2=0.986$). This study contributes to measuring the emotion quantitatively by the relation of expected and actual remaining time in multitasking environment.

• Architectural research
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• v.20 no.4
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• pp.147-152
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• 2018

As construction projects become larger, process plans become more complex, and inadequate process management leads to waste of time and resources. Effective process management requires process management techniques that can identify problems inherent in the process, continuously improve, and reflect interdependent process characteristics. In the field, the day's details by work type and work status are to be entered in the work daily report. However, even when important information is written, it is not directly linked to the overall process management. This study aims to propose specific process management and decision-making plan based on actual worker by visualizing and quantifying the information described in the existing work daily report. It is expected efficient process management to increase reliability and productivity through process management, which can increase the utilization of work daily reports and facilitates organic communication among participants.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.2
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• pp.31-39
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• 1999

A new approximation method for finding the steady-state probabilities of the number of customers present in queueing systems with Poisson arrivals and two servers with different deterministic service times with infinite waiting room capacity is developed. The major assumption made for the approximation is that the residual service times of the servers have mutually independent uniform distributions with densities equal to the reciprocals of the respective service times. The method reflects the heterogeneity of the servers only through the ratio of their service times, irrespective of the actual magnitudes and difference. The transition probability matrix is established and the steady-state probabilities are found for a variety of traffic intensities and ratios of the two service times; also the mean number of customers present in the system and in the queue, and server utilizations are found and tabulated. The method was validated by simulation and turned out to be very sharp.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.2
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• pp.84-93
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• 2021

Airline schedule is the most basic data for flight operations and has significant importance to an airline's management. It is crucial to know the airline's current schedule status in order to effectively manage the company and to be prepared for abnormal situations. In this study, machine learning techniques were applied to actual schedule data to examine the possibility of whether the airline's fleet state could be artificially learned without prior information. Given that the schedule is in categorical form, One Hot Encoding was applied and t-SNE was used to reduce the dimension of the data and visualize them to gain insights into the airline's overall fleet status. Interesting results were discovered from the experiments where the initial findings are expected to contribute to the fields of airline schedule health monitoring, anomaly detection, and disruption management.

• Journal of Forest and Environmental Science
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• v.9 no.1
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• pp.33-43
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• 1993

About 67% of all forest area in Korea belong to young age stands under II age class, including III age class which can be thinned under DBH 16cm, it comes up more than 90%. Therefore, thinking of the pressing necessity of thinning in our country this study describes the actual conditions analysis of the production of thinned small logs, points at issue and improvement measures of thinned timber production.

• Journal of the Korea Institute of Building Construction
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• v.12 no.3
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• pp.257-265
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• 2012

Many construction companies are simultaneously carrying out numerous projects in the housing construction industry. It is essential to accurately forecast the cash flow of a project through optimal process management and resource input in order to manage funds rationally and enhance the competitiveness of a company. Current cash flow forecasting methods offer lower accuracy due to a large gap between the revenue and expenditure element. Expenditure elements depends on the real-time changing actual cost for work performed. This research survey was conducted on the actual state of construction management of K company to investigate the problems of cash flow forecasting. To achieve this, the work process and construction management system were integrated to improve the cost management system of K company. To accurately forecast the cash flow of a project, revenue and expenditure elements were displayed in the total cash flow forecast window. This research is expected to assist in the implementation of a system of cash flow forecasting on housing construction by excluding negative elements of revenue and expenditure.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.74-82
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• 2022

Improving long-term performance in highway projects is an imperative goal for public administrations. Project delivery and procurement methods might provide an opportunity to align design and construction processes with this goal. Previous studies have explored whether project delivery methods impact the long-term performance of highway projects. However, these studies did not focus specifically on how core elements within the procurement might relate to long-term performance. Thus, this research aims to fill this gap by exploring to what extent and how long-term evaluation criteria are considered in design-build best-value procurement of highway projects. To this end, content analysis was conducted on 100 projects procured between 2009 and 2019 by 19 DOTs across the U.S. The analysis of 365 evaluation criteria found that (1) roughly 11% of them related to long-term performance. (2) The weight given to these criteria in the overall technical proposal was lower than 30%. (3) Sixty-five percent (65%) of long-term evaluation criteria focused on design while 15% related to materials and technology, respectively. The results of this study are a first steppingstone to initiate a deep exploration of the relationship between procurement practices and actual project performance. Currently, with sustainability and life cycle assessments being top concerns in infrastructure projects, this line of research might be of particular interest to DOTs and highway agencies across the U.S. and worldwide.

• Journal of Families and Better Life
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• v.24 no.5 s.83
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• pp.223-237
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• 2006

This study explores how well parents and their children recognize the social attitudes of one another. Mothers, fathers and youths were asked to state their own opinion on various social issues then predict their children's, fathers' and mothers' responses(attributed attitudes). Empirical evaluation of the possible socialization consequences of actual versus attributed attitudes leads to a series of hypotheses. The data were collected from single students at a university in Seoul and their parents. Included in the seven social attitude were sexuality, educational, economic, political, ecological, religious and family issues. Analysis of the responses 98-110 triads, each consisting a mother, a father and a young adult child showed that both mothers and fathers were limited in their ability to gauge the attitudes of their children. Guided by attribution theory, this study tested several hypothesized relationships between the actual response of mother, the actual response of the father, the perceived response of the mother, the perceived response of the father and the actual response of the child. The theoretical model was tested with AMOS 5.0, utilizing path analysis, which is a form of structural equation modeling with manifest variables. Overall model fit was assessed by examining GFI, NFI, TLI, CFI and RMR. Results of the data analysis can be summarized as follows. First, the children perceived their mothers and fathers to be highly similar in their opinions and the actual responses of the mothers and the fathers were considerably correlated. Second, the fathers' responses whether attributed or actual were more predictive than the mothers' responses to their children's opinions. The alternative model suggests considerable support for the attribution theory. Indeed, within a family, the actual opinions of parents appear to have little direct bearing on the child's orientations, except when the actual orientations are perceived and reinterpreted by the children. It is not what parents think, but what their children think they think that predicts their offsprings' attitudes.