• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.7-12
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• 2010

In this paper, we analyze and simulate the performance of a cooperative communication system adopting a maximum likelihood (ML) equalizer. In wireless communication systems, cooperative communication schemes employing several relays can be applied for extending the communication coverage. It is assumed that both relays and user terminals can move. Therefore, coverages of two or more relays can overlap each other. If wanted and interfering signals are transmitted through the same channel and there are one terminal in the overlapped region, its performance is degraded due to interference. Hence, we use a ML equalizer for rejecting the effect of interfering signal and enhancing the communication system performance. The cooperative system performance is evaluated in terms of bit error probability. From the simulation results, it is demonstrated that the ML receiver shows good interference cancellation performance although its complexity is high.

• Journal of Digital Contents Society
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• v.9 no.3
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• pp.471-481
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• 2008

Test scheduling considering power dissipation is an effective technique to reduce the testing time of complex SoCs and to enhance fault coverage under limitation of allowed maximum power dissipation. In this paper, a modeling technique of test resources and a test scheduling algorithm for efficient test procedures are proposed and confirmed. For test resources modeling, two methods are described. One is to use the maximum point and next maximum point of power dissipation in test resources, the other one is to model test resources by partitioning of them. A novel heuristic test scheduling algorithm, using the extended-tree-growing-graph for generation of maximum embedded cores usable simultaneously by using relations between test resources and cores and power-dissipation-changing-graph for power optimization, is presented and compared with conventional algorithms to verify its efficiency.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.728-736
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• 2009

We propose a method using the genetic algorithm to solve the maximum set cover problem. It is needed for scheduling the power of sensor nodes in extending the lifetime of the wireless sensor network with variable sensing range. The existing Greedy Heuristic method calculates the power scheduling of sensor nodes repeatedly in the process of operation, and so the communication traffic of sensor nodes is increased. The proposed method reduces the amount of communication traffic of sensor nodes, and so the energies of nodes are saved, and the lifetime of network can be extended. The effectiveness of this method was verified through computer simulation, and considering the energy losses of communication operations about 10% in the network lifetime is improved.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.10
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• pp.761-765
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• 2009

This research aims an optimal placement of Mobile Base Station (MBS) under HAP based network configurations with the restrictions of HAP capabilities. With clustering algorithm based on BIRCH, mobile ground nodes are clustered and the centroid of the clusters will be the location of MBS. The hierarchical structure of BIRCH enables mobile node management by CF tree and the restrictions of maximum nodes per MBS and maximum radio coverage are accomplished by splitting and merging clusters. Mobility models based on Jeju island are used for simulations and such restrictions are met with proper placement of MBS.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.4
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• pp.41-52
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• 2013

This study was carried out in order to analyze the succession characteristics of the slope of expressways and the results of analysis by collecting and analyzing various literatures and data from 2011 to 2012 and surveying 75 expressway slope, as follows : The construction methods applied to planting the slope of an expressway can be classified into 4 types including 3 Climber planting methods, 8 Vegetation thick-layer spray work methods, 4 Seed spray work methods, and 4 Stabilization work methods. The factors which affect the cover degree of the slope of an expressway were found to be development years, gradient, length, and azimuth. Like surrounding forest areas, the expressway slope was analyzed to begin the plant succession 20, 30, and 40 years after development, and plant succession was developed in diversity in a mixed stand forest according to surrounding forest floors. Species diversity, maximum species diversity, and the evenness of slope facing north were analyzed to be high comparing to those facing east, west, and south according to azimuth of slope. Species diversity, maximum species diversity, evenness of slope, and the plant succession of surroundings were analyzed to be high when the gradient of the slope was less than $40^{\circ}$. The dominant species which success on the slope of an expressway and its surrounding forest area included Miscanthus sinensis var. purpurascens, Zoysia japonica, Pinus thunbergii Parl, Rubus crataegifolius, Lespedeza cyrtobotrya, Amorpha fruticosa, Artemisia princeps var. orientalis, and Oenothera biennis.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.9
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• pp.29-37
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• 1998

In weighted random pattern testing it is an important issue to find the optimal weight sets for achieving a high fault coverage using a small number of weighted random patterns. In this paper, a new weight set optimization algorithm is developed, which can generate the optimal weight sets in an efficient way using the sampling probabilities of deterministic tests patterns. In addition, the simulation based method of finding the proper maximum Hamming distance is presented. Experimental results for ISCAS 85 benchmark circuits prove the effectiveness of the new weight set optimization algorithm and the method of finding the proper maximum Hamming distance.

• Proceedings of the Korean Association for Survey Research Conference
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• 2006.06a
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• pp.131-159
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• 2006

This paper consider multinomial group testing which is concerned with classification each of N given units into one of k disjoint categories. In this paper, we propose exact Bayesian, approximate Bayesian, bootstrap methods for estimating individual category proportions using the multinomial group testing model proposed by Bar-Lev et al (2005). By the comparison of Mcan Squre Error (MSE), it is shown that the exact Bayesian method has a bettor efficiency and consistency than maximum likelihood method. We suggest an approximate Bayesian approach using Markov Chain Monte Carlo (MCMC) for posterior computation. We derive exact credible intervals based on the exact Bayesian estimators and present confidence intervals using the bootstrap and MCMC. These intervals arc shown to often have better coverage properties and similar mean lengths to maximum likelihood method already available. Furthermore the proposed models are illustrated using data from a HIV blooding test study throughout California, 2000.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.7
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• pp.2047-2066
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• 2024

In order to improve the coverage and achieve massive spectrum access, non-orthogonal multiple access (NOMA) technology is applied in millimeter wave massive multiple-input multiple-output (mMIMO) communication network. However, the power assumption of active sensors greatly limits its wide applications. Recently, Intelligent Reconfigurable Surface (IRS) technology has received wide attention due to its ability to reduce power consumption and achieve passive transmission. In this paper, spectral efficiency maximum problem in the millimeter wave mMIMO-NOMA system with IRS is considered. The sparse RF chain antenna structure is designed at the base station based on continuous phase modulation. Furthermore, a joint optimization problem for power allocation, power splitting, analog precoding and IRS reconfigurable matrices are constructed, which aim to achieve the maximum spectral efficiency of the system under the constraints of user's quality of service, minimum energy harvesting and total transmit power. A three-stage iterative algorithm is proposed to solve the above mentioned non-convex optimization problems. We obtain the local optimal solution by fixing some optimization parameters firstly, then introduce the relaxation variables to realize the global optimal solution. Simulation results show that the spectral efficiency of the proposed scheme is superior compared to the conventional system with phase shifter modulation. It is also demonstrated that IRS can effectively assist mmWave communication and improve the system spectral efficiency.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.91_92
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• 2009

As the increasing integrity of VLSI, the BIST(Built-In Self Test) is used as an effective method to test chips. Generally the pseudo-random test pattern generation is used for BIST. But it requires too many test patterns when there exist random resistant faults. Therefore we propose a mixed test scheme which applies to the circuit under test, a deterministic test sequence followed by a pseudo-random one. This scheme allows the maximum fault coverage detection to be achieved, furthermore the silicon area overhead of the mixed hardware generator can be reduced.

• Korean Chemical Engineering Research
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• v.53 no.6
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• pp.770-775
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• 2015

Adsorption of Congo Red (CR) from dye-containing effluents using modified bentonite (MB) has been investigated here. Isothermal studies were conducted to ascertain maximum adsorption capacity of the adsorbent. MB exhibited superior adsorption capacity compared to other low-cost adsorbents. Experimental data fitted the Langmuir isotherm better, indicating monolayer coverage of CR on MB. The feasibility of the process was measured in terms of separation factor $R_L$. The values of Gibbs free energy, entropy and enthalpy were calculated from the thermodynamics of the process. Adsorption was feasible and spontaneous, being endothermic. Analytical techniques including SEM, EDS, FTIR and XRD were applied to characterize MB and also to provide conclusive proof of the accumulation of CR on to MB.