• Journal of Fisheries and Marine Sciences Education
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• v.26 no.2
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• pp.444-454
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• 2014

The range of optimization problem in aquaculture is very wide, resulting from the range of species, mode of operation. Quite a few studies focus marine net-cages, but studies on land based culture farm are few or no. This paper considers a allocation problem to meet production planning in land based aquaculture system. A water pool allocation model in land based aquaculture system was developed. The solution finds the value of decision variable to minimize yearly production costs that sums up the water pool usage cost and sorting cost. The model inputs were (1) the fish growth rate (2) critical standing corp (3) number of water pool (4) number of fish. The model outputs were (5) number of water pool in growing phase (6) cost of cultivation (6) optimal facility allocation(number of water pool for each growing phase). To solve the problem, an efficient heuristic algorithm based on a greedy manner is developed. Branch and bound and heuristic is evaluated through numerical examples.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2338-2353
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• 2015

In this paper, the optimal power allocation algorithm that minimizes the aggregate bit error rate (BER) of the secondary user (SU) in a downlink orthogonal frequency division multiplexing (OFDM) based cognitive radio (CR) system, while subjecting to the interference power constraint and the transmit power constraint, is investigated under the assumption that the instantaneous channel state information (CSI) of the interference links between the secondary transmitter and the primary receiver, and between the primary transmitter and the secondary receiver is perfectly known. Besides, a suboptimal algorithm with less complexity is also proposed. In order to deal with more practical situations, we further assume that only the channel distribution information (CDI) of the interference links is available and propose heuristic power allocation algorithms based on bisection search method to minimize the aggregate BER under the interference outage constraint and the transmit power constraint. Simulation results are presented to verify the effectiveness of the proposed algorithms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.1-8
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• 2004

In this paper, we proposed ARAHE(Adaptive Resource Allocation algorithm for HIPERLAN/2 with Error channel). It uses EIB(Error Indication Bits) for efficient resource allocation. We evaluate the performance of ARAHE by simulation and the result shows ARAHE has better performance than current method in the case of delay, utilization and TSR(Transmission Success Rate).

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1404-1414
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• 2016

Cross-layer design is a concept, which captures the dependencies and interactions and enables information sharing among layers in order to improve the network performance and security. There are two key challenges in wireless networks, lossy features of links and power assumption of network nodes. Cross-layer design of congestion control and power allocation in wireless lossy networks has been studied in the existing literature; however, there has been no contribution proposed in the literature that exploits the path diversity. In this paper, we are motivated to develop a cross-layer design of congestion control and power allocation, which takes into account lossy features of wireless links and transmission powers of network nodes and can be implemented in a distributed manner. Numerical simulation is conducted to illustrate the performance of our proposed algorithm and the comparison with current alternative approaches.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4823-4843
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• 2017

In this paper, an improved utility-based cross-layer dynamic subcarrier allocation (DSA) algorithm is proposed for single carrier frequency division multiple access (SC-FDMA) system, which adopts adaptive service rate control (ASRC) to eliminate the service rate waste and improve the spectral efficiency in heterogeneous network including non-real-time traffic and real-time traffic. In this algorithm, furthermore, a first in first out (FIFO) queuing model with finite space is established on the cross-layer scheduling framework. Simulation results indicate that by taking the service rate constraint as the necessary condition for optimality, the ASRC algorithm can effectively eliminate the service rate waste without compromising the scheduling performance. Moreover, the ASRC algorithm is able to further improve the quality of service (QoS) performance and transmission throughput by contributing an attractive performance trade-off between real-time and non-real-time applications.

• Journal of Digital Contents Society
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• v.2 no.2
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• pp.129-138
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• 2001

With the explosive growth and pervasive of the Internet, dynamic bandwidth allocation is nessary for ATM streams that carry various traffic. In order to provide quality of service(QoS) guarantees and to give the minimum cell rate, new bandwidth allocation scheme requires to be implemented. DFBA(Differential Fair Buffer Allocation) scheme is one of the methods for ATM GFR(Guaranteed Frame Rate) services. DFBA scheme treats cells selectively in a region between low buffer occupancy threshold and high buffer occupancy threshold. A big unbalance is introduced when the value being selected by DFBA scheme is greater than minimum rate. In a try to reduce the unbalance modified DFBA scheme is proposed. Selecting parameter according to the situation of network, this scheme is very effective to control the bandwidth in the various network situation.

• ETRI Journal
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• v.37 no.6
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• pp.1242-1250
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• 2015

It is very important to provide a parameterized quality of service (QoS) using traffic specification (TSPEC), such as mean data rate, maximum burst size, and peak data rate, when packets from the application layer need to be transmitted with guaranteed services in a high-rate wireless personal area network (HR-WPAN). As medium resources are limited, the optimal medium time required for each device needs to be estimated to share the resources efficiently among devices. This paper proposes a variable-service interval-based resource allocation algorithm to efficiently make a reservation of medium resources based on a parameterized QoS. In other words, the proposed algorithm calculates the number of medium access slots (MASs) based on TSPEC, local resources, and local conditions and determines suitable locations for the MASs within a superframe to accommodate more devices. The simulation results show that the proposed algorithm can accommodate more devices and has greater than 10% resource allocation efficiency in an HR-WPAN compared to existing schemes.

• 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.34 no.3A
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• pp.281-289
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• 2009

Wireless relay attracts great attention as a core technology of next generation wireless communication systems since it enables reliable communications and extends cell coverage by supporting shadowed users. In this paper, we Propose transmit power and subcarrier allocation scheme for downlink OFDM systems with multiple decode and forward (DF) relays to increase data rate with fixed bit error rate (BER) and sum power constraint. In simulation results, average data rate based on the proposed schemes are evaluated and compared to that of the other schemes. It is also shown that the performance loss of the proposed scheme is negligible compared to the optimal scheme, while its computational complexity is reduced considerably.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.295-302
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• 2014

OFDM technique uses multiple sub-carriers for the data transmission. Therefore, inter carrier interference is generated because of nonlinear high power amplifier and carrier frequency offset. Wireless OFDM transmission over Doppler fading channels also causes inter carrier interference. The interference increases the bit error rate in receiver. Sub-carrier allocation methods in LTE and WiMAX standards are different. The performance of OFDM systems using different sub-carrier allocation, gauged by the bit error rate, is analyzed considering the nonlinear high power amplifier, carrier frequency offset and Doppler fading channels.