• KDI Journal of Economic Policy
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• v.13 no.4
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• pp.59-90
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• 1991

The purpose of this paper is to determine whether the rate schedule of the Korean income tax system embodies the theoretically desirable distribution of the tax burden by income classes. The paper follows the approach of Young (1990) who has estimated the utility function and calculated the magnitude of sacrifice, i.e., the tax burden. The main point of the study is to estimate the utility function. The estimation results may differ if different data sets are used. Therefore, this paper employs the effective as well as the nominal tax rate schedule. The findings derived in this paper are 1) that the effective rate schedule is more appropriate in estimating the utility function; 2) that the middle class has born the relatively heavier burden over time; 3) that the current income tax credit scheme curtails the tax burden on the middle class while intensifying the tax burden of the lower and upper income classes; 4) that reducing the amount of deduction moves the distribution of tax burdens by income classes closer to the theoretically desirable model; 5) that the rate schedule of the Korean income tax system, particularly in 1991, did not conform to the desired model as did the tax systems of developed countries such as the United States, Italy, Japan, and Germany.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.199-212
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• 2010

To establish an infrastructure for technology and information in the domestic construction industry, several construction regulations pertaining to construction information have been institutionalized. However, there are major problems with the domestic information classification system, earned value management (EVM) and project management information system (PMIS). In particular, the functions of the current PMIS have consisted of a builder-oriented system, and as EVM is not applied to PMIS, the functions of reporting, analysis and forecast for owners are lacking. Moreover, owners cannot confirm information on construction schedule and cost in real time due to the differences between the EVM and PMIS operation systems. The purpose of this study is to provide a framework that is capable of operating PMIS efficiently under an e-business environment, by providing a proposal on how to establish a work breakdown structure (WBS) and an EVM - PMIS integration model, so that PMIS may provide the function of EVM, and stakeholders may have all information in common. At the core of EVM - PMIS integration is the idea that EVM and PMIS have the same operation system, in order to be an activity-based system. The principle of the integration is data integration, in which the information field of an activity is connected with the field of a relational database table consisting of sub-modules for the schedule and cost management function of PMIS using a relational database management system. Therefore, the planned value (PV), cost value (CV), actual cost (AC), schedule variance (SV), schedule performance index (SPI), cost variance (CV) and cost performance index (CPI) of an activity are connected with the field of the relational database table for the schedule and cost sub-modules of PMIS.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.298-301
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• 1996

This paper addresses the effects of an imperfect production process on the optimal production quantity and quality inspection policies. The system is assumed to deteriorate during the production process. The results are either defective products or machine breakdown whether multiple quality inspection is worth or not. Furthermore, when multiple inspection policy is adopted, the optimal inspection schedule is shown to be equally spaced throughout the production cycle. Exact solution and approximation of the optimal production quantity and approximation of the optimal number of inspection are provided. Finally, to better understand the model of this paper, comparisons between this model and classical EMQ model are provided.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.504-508
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• 2003

Cost and schedule are the major concerns for the successful construction project management. The four dimensional CAD (4D CAD) integrating graphical data and scheduling data has also been an area of research interests for improving construction controls. In order to achieve the benefits from these areas in an integrated way, this study proposes a 4D-EVMS system for the owners. Managerial requirements for cost and schedule control for the owners are identified first. A 4D-EVMS model is then proposed which provides functional flexibility in order to enhance the efficiency of the system. Lessons learned and practical implications are briefly summarize.

• The Journal of the Korea Contents Association
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• v.2 no.1
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• pp.7-15
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• 2002

In this paper, 1 design a mode of educational contents for Problem Based Learning(PBL) fitted education using ICT. I design a teaching and loaming schedule for PBL using ICT. I search pertinent items of educational contents to provide to student in PBL and design a mood fitted them. ,also, 1 design a pertinent mode of system to carry out a teaching and teaming schedule. Therefor, a teaching and learning schedule designed in this paper will apply easily. Because PBL manages ill-structured problem reflected the actuality and is high ratio which student participate in instruction, 1 expect that we take the effect of instruction using ICT in PBL.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.2
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• pp.131-144
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• 2010

IT developed countries since the late 1980s are used to develop IT security evaluation criteria to ensure safety and reliability of information protection products. Currently a variety of products used for the evaluation based on CC and it takes a long period of product evaluation is required to reduce the developers and users. In this paper refer to the published standard evaluation schedule for the EAL4 calculation model offers a trial period. In addition, based on this commitment by adjusting the number of evaluaters to evaluate the applicant in the evaluation period to minimize the position offers.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.596-601
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• 2013

In the current pavement construction practice, the state agencies traditionally determine the quality of the as-constructed pavement mix based on individual mixture material parameters (e.g., air voids, cement or asphalt content, aggregate gradation, etc.) and consider these parameters as key variables to influence payment schedule to the contractors and the present and future quality of the as-constructed mixture. A set of empirically pre-determined pay adjustment schedule for each parameter that was differently developed and being used by the individual agencies is then applied to a given project, in order to judge whether each parameter conforms to the designated specifications and consequently the contractor may either be rewarded or penalized in accordance with the payment schedule. With an improved quality assurance system, the Performance Related Specification, the individual parameters are not utilized as a direct judgment factor; rather, they become independent variables within a performance prediction function which is directly used to predict the performance. The quantified performance based on the prediction model is then applied to evaluate the pavement quality. This paper presents the brief history of the quality assurance in asphalt pavement construction including the Performance Related Specifications, statistical performance models in terms of fatigue and rutting distresses, as an example of the performance prediction models, and envisions the possibilities as to how this Performance Related Specification could be utilized in other infrastructures construction quality assurance.

• Journal of Korea Multimedia Society
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• v.23 no.10
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• pp.1270-1285
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• 2020

As a representative concept of the fourth industrial revolution era where everything is digitized, digital twin means analyzing and optimizing a complex system using a simulation model synchronized with the system. In this paper, we propose a digital twin simulation model for the efficient operation of urban railways in Busan. Due to the geopolitical nature of Busan, where there are many mountains and narrow roads, the railways are more useful than other public transportation. However, this inversely results in a high level of congestion, which is an inconvenience to citizens and may be fatal to the spread of the virus, such as COVID19. Considering these characteristics, the proposed model analyzes the congestion level of the railways in Busan. The model is developed based on a mathematical formalism called discrete-event system specification and deduces the congestion level and the average waiting time of passengers depending on the train schedule. In addition, a new schedule to reduce the congestion level is derived through particle swarm optimization, which helps the efficient operation of the railways. Although the model is developed for the railways in Busan, it can also be used for railways in other cities where a high level of congestion is a problem.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.4
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• pp.116-122
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• 2013

This study develops a dynamic scheduling model for parallel machine scheduling problem based on genetic algorithm (GA). GA combined with discrete event simulation to minimize the makespan and verifies the effectiveness of the developed model. This research consists of two stages. In the first stage, work sequence will be generated using GA, and the second stage developed work schedule applied to a real work area to verify that it could be executed in real work environment and remove the overlapping work, which causes bottleneck and long lead time. If not, go back to the first stage and develop another schedule until satisfied. Small size problem was experimented and suggested a reasonable schedule within limited resources. As a result of this research, work efficiency is increased, cycle time is decreased, and due date is satisfied within existed resources.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.195-207
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• 2007

The urban railways connecting between the inner city and suburb of Seoul metropolitan area, has lost the competitiveness against cars because too many stops deteriorated operating speed and passenger's level of service. This paper suggests that an express train should be introduced into the urban railway system in order to sort out such a complication. There are two considerations in the present study. Firstly, train schedule problem should be taken into account. In this regard, a new model for urban railway system was developed by revising the existing models dealing with single line freight railway. Approximate branch and bound algorithm based on conflict group rather than a single conflict was adopted. Consequently, it was found that the time saving in calculating the optimal schedule is the most meaningful contribution of the algorithm. The second consideration is associated with the application of the model. A case study was carried out using the actual operation data from Ansan line. In conclusion, the operation speed of the line can increase considerably with minimal number of new sidings.