• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.101-109
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• 2011

The purpose of this study was to establish the methodology for providing the environmental flows from irrigation reservoir. Reservoir water budget for study area was analyzed to simulate the water supply scenarios for environmental flows. Bonghyun and Hi reservoirs area, located in Gyeongnam, Gosung-gun, Hi-myeon, were selected for study watersheds and streams for this study. Reservoir operation was simulated to determine the envionmental flows supply amount from March to October with the constraint that environmental flow supply was restrained when the storage of reservoir were below the half or one-third of effective storage. The simulated results indicated that the supply of environmental flows with the amount of 200 ton/day and 600 ton/day resulted in up to 15 mm and 29 mm of runoff depth increase in the downstream, respectively. The effect of environmental flows supply from existing irrigation reservoir was not significant because the irrigation reservoir was not designed to supply the environmental flows. It is necessary to remodel the irrigation reservoir and develop the reservoir operation technique, to meet the need for the environmental flows.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.3
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• pp.101-109
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• 2008

This paper considers an integrated decision for scheduling and outsourcing(or, subcontracting) of a finite number of jobs(or, orders) in a time-sensitive make-to-order manufacturing environment. The jobs can be either processed in a parallel in-house facilities or outsourced to subcontractors. We should determine which jobs should be processed in-house and which jobs should be outsourced. And, we should determine the schedule for the jobs to be processed in-house. If a job is determined to be processed in-house, then the scheduling cost(the completion time of the Job) is imposed. Otherwise(if the job should be outsourced), then an additional outsourcing cost is imposed. The objective is to minimize the linear combination of scheduling and outsourcing costs under a budget constraint for the total available outsourcing cost. In the problem analysis, we first characterize some solution properties and then derive dynamic programming and branch-and- bound algorithms. An efficient heuristic is also developed. The performances of the proposed algorithms are evaluated through various numerical experiments.

• Journal of the military operations research society of Korea
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• v.36 no.2
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• pp.1-10
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• 2010

Learning rate is generally applied to estimate an appropriate production labor cost. Learning effect is obtained from repetitive work during the production period under 3 assumptions ; homogeneous production, same producer, quantity measure in continuous unit. However, production breaks occur frequently in Korean defense industry environment because of budget constraint and annual requirements. In this case previous learning effect can not be applied due to learning loss. This paper proposed the application of learning rate when a production break occurs in Korea defense industry. To obtain a learning loss, we surveyed various learning loss factors for different production breaks(6, 12, 18 months) from 4 defense industry companies. Then, we estimate the first unit labor hours in re-production phase after production break using Anderlohr method and Retrograde method with the result of the survey. This work is the first attempt to show a method which defines and evaluates the learning loss factors in Korean defense industry environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1461-1470
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• 1998

Bit allocation or quantizer assigning problem is a basic and essential issue in lossy picture coding. It could be represented as minimizing overall distortion with the given constraint that total bits should not exceed allowed bit-budget. Optimal solution can be found by Lagrangian method. However this method needs much computational time and memory. This paper presents an approximation method that uses the activity measure. The comparison between the existing activity measuring techniques are made, and mapping function from activity value to the quantizer is proposed. Under MPEG-1 Intra coding situation, simulations show almost identical results compared to the optimal ones obtained by Lagrangian method with reduced computational time.

• Journal of Information Technology Services
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• v.14 no.3
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• pp.85-97
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• 2015

The information and communications construction business has the characteristics of an infrastructure industry and responsibility for the construction and maintenance of all ICT infrastructures. With the recent proliferation of the smart convergence of various industries based on ICT infrastructure, the role of the information and communications construction business has been highlighted to accommodate the convergence and implementation environment in construction and medical industries. Therefore, this paper seeks policy measures to establish the new role of the information and communications business under the rapidly developing smart convergence environment and the priorities of policy measures to strengthen the capability of the information and communications business using a quantitative model. The analysis result suggests that the difference in importance of each policy measure should be considered in order to execute effectively the policy of promoting the information and communications construction business. Given the constraint of limited budget, policy priorities include the development of new markets, and establishment of incentive for new technology. This study is significant for its theoretical contribution, being the first quantitative approach to policy priorities for the promotion of information and communications construction business under the smart convertgence environment.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.297-300
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• 2004

This paper proposes a method for choosing the best composite power system expansion plan considering probabilistic reliability criterion. The proposed method was modeled as the minimization of the investment budget (economics) for constructing new transmission lines subject to not only deterministic(demand constraint) but also probabilistic reliability criterion(LOLE) with considering the uncertainties of the system elements. This is achieved by modeling the power system expansion problem as an integer programming one. The method solves for the optimal strategy using a probabilistic theory based branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Although the proposed method is applied to a simple sample study, the test results demonstrate a fact that the proposed method is suitable for solving the power system expansion planning problem subject to practical uncertainties for future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.3887-3907
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• 2015

This paper introduces a full duplex single secondary user multiple-input multiple-output (FD-SSU-MIMO) cognitive radio network, where secondary user (SU) opportunistically accesses the authorized spectrum unoccupied by primary user (PU) and transmits data based on FD-MIMO mode. Then we study the network achievable average sum-rate maximization problem under sum transmit power budget constraint at SU communication nodes. In order to solve the trade-off problem between SU's sensing time and data transmission time based on opportunistic spectrum access (OSA) and the power allocation problem based on FD-MIMO transmit mode, we propose a simple trisection algorithm to obtain the optimal sensing time and apply an alternating optimization (AO) algorithm to tackle the FD-MIMO based network achievable sum-rate maximization problem. Simulation results show that our proposed sensing time optimization and AO-based optimal power allocation strategies obtain a higher achievable average sum-rate than sequential convex approximations for matrix-variable programming (SCAMP)-based power allocation for the FD transmission mode, as well as equal power allocation for the half duplex (HD) transmission mode.

• KDI Journal of Economic Policy
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• v.30 no.1
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• pp.131-170
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• 2008

Korea's public assistance system, represented by NBLS(National Basic livelihood Security), has disclosed critical problems despite the rapid increase in its budget, such as decreasing work incentive and deepening welfare trap. These typical problems of classical welfare system have been commonly witnessed in many other advanced countries. Therefore a number of efforts have been exerted to correct these problems by transferring the existing welfare system into a welfare-to-work(or workfare) system, and the most common one of such efforts is introducing the EITC(Earned Income Tax Credit)-type programs. They have already been implemented in many countries such as the USA, the UK and France, also Korean government decided to launch EITC program in 2009. This paper aims to propose some measures to improve Korean EITC program. For this, an optimization problem is constructed from the government's viewpoint. Optimal EITC program is defined to be a solution to the problem - a combination of phase-in rate, phase-out rate, and maximum credit that maximizes labor supply increase under a exogenously given budget constraint. Using a mechanism design analysis, we derive and characterize the optimal EITC program. Analysis results implies that Korean EITC structure needs to be modified so that phase-in rate is larger than phase-out rate and the upper limit of phase-out range becomes larger. Comparative static analysis results show that the feature of the optimal EITC program is sensitive to the change of income distribution, suggesting that if beneficiaries are categorized into different income groups, then it is desirable to apply distinctive EITC programs to each group.

• KDI Journal of Economic Policy
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• v.33 no.2
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• pp.111-143
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• 2011

As the 'jobless growth' is developing into a worldwide phenomenon, many countries try to recover a virtuous relationship between the growth and employment using various wage subsidy programs. This study focuses on wage subsidy to employers, labor demand-side wage subsidy for which one can think of two types-a tax credit(a flat wage subsidy) and a social insurance premium exemption(a proportional wage subsidy). For job creation, Korean government reintroduced a tax credit to small and medium-sized enterprises(SMEs) which have increased their employment level in 2010. But many experts has continuously insisted that it should be replaced with a social insurance premium exemption arguing only a few SMEs benefit from the tax credit as most of them are actually not paying any corporate or general income tax bills. However, as the insurance premium exemption accompanies an increase in the amount of budget with the coverage widen, one cannot confirm its cost effectiveness over the tax credit. This paper aims to provide a theoretical analysis to derive some formal conditions under which a social insurance premium exemption creates more jobs than a tax credit does given a budget constraint. We show that the former's dominance over the latter depends on whether there exists a dead zone of social insurance or not. If there does not exist a dead zone, a social insurance premium exemption is more desirable in many cases, whereas one cannot guarantees its dominance over a tax credit if there exists a dead zone. Therefore in order to realize its dominance, the government should minimize a dead zone so that most SMEs effectively benefit from the insurance premium exemption. In addition, applying discriminative exemption rates which reflect each firm's job conditions such as wage level and labor demand/supply sensitivity, the government try to enhance job creation effect.

• Korea Real Estate Review
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• v.28 no.1
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• pp.23-37
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• 2018

The genetic algorithm (GA) and branch and bound (B&B) methods are the useful methods of searching the optimal project combination (combinatorial optimization) to maximize the project effect considering the budget constraint and the balance of regional development with regard to the Urban Regeneration New Deal policy, the core real estate policy of the Moon Jae-in government. The Ministry of Land, Infrastructure, and Transport (MOLIT) will choose 13 central-city-area-type projects, 2 economic-base-type projects, and 10 public-company-proposal-type projects among the numerous projects from 16 local governments while each government can apply only 4 projects, respectively, for the 2017 Urban Regeneration New Deal project. If MOLIT selects only those projects with a project effect maximization purpose, there will be unselected regions, which will harm the balance of regional development. For this reason, an optimization model is proposed herein, and a combinatorial optimization method using the GA and B&B methods should be sought to satisfy the various constraints with the object function. Going forward, it is expected that both these methods will present rational decision-making criteria if the central government allocates a special-purpose-limited budget to many local governments.