• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.721-725
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• 2014

In this paper, we propose a fast adaptive power allocation method for an orthogonal frequency division multiple access (OFDMA) system that employs an adaptive modulation and coding (AMC) scheme. The proposed scheme aims to reduce the calculation complexity of greedy adaptive power allocation (APA), which is known as the optimal algorithm for maximizing the utility argument of power. Unlike greedy APA, which starts power allocation from "0", the proposed algorithm initially allocates a certain level of power determined by the water-filling scheme. We theoretically demonstrate that the proposed algorithm has almost the same capability of maximizing the utility argument as the greedy APA while reducing the number of operations by 2M, where M is the number of AMC levels.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.500-504
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• 2008

The objective of this paper is to evaluate the feasibility of using an optimization model as a effective way to search conjunctive operation scheme to meet two conditions; one is to minimize the electric cost for pumping and another is to meet the water demand for satisfying customers. The feasibility is confirmed as comparing the best combinations of pumps between multi-regional water supply networks from multiple sources which are obtained through an optimization modeling and EPAnet modeling. KModsim model, a network optimization model, was used to determine conjunctive operation scheme in the pipe system. KModsim, based on Lagrangian Relaxation algorithm, is useful for modeling network system and obtaining simultaneously pump combination and water allocation with given input option such as energy unit cost supplying from a source into a consumer, operating pumping combination. This study develops the procedure of determining optimal conjunctive operation scheme with using KModsim model. As a study region, the water supplying systems of the Geojae-city in the Geongsang Namdo Province was selected and investigated. The EPAnet hydraulic simulation result(Ryu et al, 2007, KSWW) gave input data for optimization model; energy unit price(won/$m^3$), water service available area etc.. It was assured that the combination of pump operation through optimum conjunctive operation is to be optimum scheme to obtain the best economic water allocation with comparison to the hydraulic simulation result such as electric cost and pump combination cases. The results obtained through the study are as follows. First, It was found that a well-allocated water supply scheme, the best combination of pump operation through optimum joint operation, promises to save the electric cost and satisfy all operational goals such as stability and revenues during the period. Second, an application of KModSim, a network model, gave the amount of water allocation from each source to a consumer with consideration of economic supply. Finally, in a service area available to supply through conjunctive operation of existing inter-regional water supply networks within short distance, a conjunctive operation is useful for determining each transmission pipeline's service area and maximizing the effectiveness of optimizations in pumping operation time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.5
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• pp.311-318
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• 2009

In previous study, a new allocation methodology of common cost on multi-product have been suggested. The aim of this study is to suggest the methodology that allocates an environment pollution cost including carbon emission cost to each cost of multi-product. For this study, a supposed multi-energy system composed of twenty kinds of systems was made. The multi-energy system produces eighteen kinds of outputs that are electricity, steam, hot water, chilled water, ice, warm air, and cooling air from seven kinds of energy source that are LNG, coil, geothermal energy, sun heat, hydrogen, bio-mass, and waste. The new methodology was applied to the multi-energy system in order to allocate the environment pollution cost to each production cost, and twenty seven equations were induced. From this result, it is concluded that this methodology can estimate each unit cost and allocate each cost flow in any product of any energy system.

• Journal of environmental and Sanitary engineering
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• v.20 no.3 s.57
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• pp.51-56
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• 2005

Allocation of water pollution load from loading capacity can be much essential, controversial, and its standards can be applied case-by-case to the various situations. Allocation methods to point sources are generally 'Equal effluent concentration', 'Equal percent Treatment', Loading capacity at planning stage consists of basic pollution load, development pollution load, reserved pollution load and margin of safety. But at the implementing stage loading capacity can be consisted of allocatable load and margin of safety to give more flexibility in the total water pollution load management plan. In that case, we can re-adjust and altogether use the pollution load of point sources of series and non-point sources at the implementing stage.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.9
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• pp.629-640
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• 2014

In this study, the applicability of dynamic water quality model to TMDL system was examined, methods for setting of water quality goal and estimation of allocation loads were suggested and results of applying these methods were analyzed. HSPF model was applied for Miho stream basin as a dynamic water quality model. The model was calibrated using measurement data obtained in 2009~2010 and showed satisfactory performance in predicting daily variations of flow rate and BOD concentration. Methods for TMDL application were categorized into 3 cases; water quality management (1) considering low flow condition(Case I), (2) considering entire period of the year (Case II) and (3) considering the worst water quality condition (Case III). BOD water quality goals at the end of Miho stream watershed increased in the order of Case IICase I>Case III. If further researches on base precipitation and method for model input of nonpoint source pollutant were carried out, water quality could be managed more reasonably and scientifically by applying dynamic water quality model to TMDL. The result of this study is expected to be used as primary data for TMDL using dynamic water quality model.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.82-90
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• 2010

New Zealand appears to be a water rich country; however there are considerable water allocation issues. Mostly these revolve around balancing environmental concerns with economic development. The largest economic sector is agriculture which currently utilizes around 80% of the allocated water and has considerable potential to increase in size. The resource management framework that New Zealand has developed over the past twenty years revolves around local decision-making and sustainable management principles. As the demands for water have grown there has been growing concern that this framework is inadequate to deal with the issues of declining water quantity and quality through agricultural intensification. In Canterbury, the region with the highest water allocation and demand, a new approach is being trialed. The Canterbury Water Management Strategy (CWMS) recognizes the need for: ecological restoration for past damage; infrastructure development for increased irrigation; and the need to link infrastructure with more efficient use of water by both existing and new water users. These three elements are recognized as having equal value. The CWMS builds on the local decision-making concept but is deliberately aimed at consensus building in order to remove expensive and adversarial resource management hearings. It is practical enough to recognize that economic development is needed but that it need not proceed in conflict with the environment, but rather can be a means towards environmental improvement.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.63-72
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• 2007

The main purpose of this study is that financial resources allocation criteria are examined closely between central government and local government as well as among local government in a river basin. Financial resources allocation principles reflecting water use, flood control, and water quality improvement are reviewed and derived two categories such as common factors and individual factors. The weights of each factor are assigned by analytical hierarchy process. The results of applying four river basins (Han river, Geum river, Nakdong river, Yeongsan-seumjin river) show that rational raising of financial resources are different according to the characteristics of each river basin. Findings are as follows: In case of Han river and Yeongsan Seumjin river, benefit principle and polluter pay principle by individual factors are more attractive than other Principles. Solvency principle by common factor is more acceptable than the other principles in Nakdong-river and Geum-river.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.19-27
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• 2011

In this paper, we propose the data stream allocation algorithms for maximizing sum capacity of downlink multiuser MIMO (Multiple-input Multiple-output) systems with BD (Block Diagonalization). The conventional BD precoding algorithms maximize the capacity by controlling power against channel gain of each user. In multiuser MIMO systems, however, the number of data streams for each user can be used to as another control parameter, which determines the capacity. This paper proposes the data stream allocation algorithm of BD for increasing capacity in multiuser MIMO systems. The proposed algorithm allocates unequal bit stream to each user based on channel matrix of each user for maximizing sum capacity. It is proved that proposed algorithm can achieve the significantly improved sum capacity by computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.9
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• pp.753-761
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• 2012

In this paper, we study a power allocation technique for Tomlinson-Harashima precoding (THP) in multi-user multiple input single output (MISO) downlink systems. In contrast to previous approaches, a mutual information based method is exploited for maximizing the sum rate of zero-forcing THP systems. Then, we propose a simple power allocation algorithm which assigns proper power level for modulo operated users. Simulation results show that the proposed scheme outperforms a conventional water-filling method, and it provides similar performance with near optimal method with much reduced complexity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.998-1004
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• 2004

In this paper we propose a discrete bit-loading algorithm that maximizes the transmit bit rate using the channel information. to optimize the performance of the very high-speed digital subscriber line(VDSL) system under the constraint of a maximum transmit power for each user. When the power level of crosstalk is high, the power allocation of a user changes the crosstalk experienced by the other users in the same binder. In this case, the performance of DSL modems can be improved by jointly considering the bit and power allocation of all users Simulation results shows that the proposed method improves the performance compared With that of iterative water-filling method.