• Journal of National Security and Military Science
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• s.1
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• pp.345-360
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• 2003

To build an information oriented armed forces, the Korean military telecommunication networks adopt TCP/IP standard communication infrastructures based on ATM packet switched networks. Utilizing this network infrastructure, the Korean armed forces also applies to the areas of battleship management for efficient operation command controls and resource management for efficient resource allocations. In this military communication networks, it is essential to determine the least cost network topology under equal performance and reliability constraints. Basically, this type of communication network design problem is known in the literature as an NP Hard problem. As the number of network node increases, it is very hard to obtain an optimal solution in polynomial time. Therefore, it is reasonable to use a heuristic algorithm which provides a good solution with minimal computational efforts. In this study, we developed a simulated annealing based heuristic algorithm which can be utilized for the design of military communication networks. The developed algorithm provides a good packet switched network topology which satisfies a given set of performance and reliability constraints with reasonable computation times.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.264-267
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• 2003

Multiple sequence alignment is a useful tool to identify the relationships among protein sequences. Dynamic programming is the most widely used algorithm to obtain multiple sequence alignment with optimal cost. However dynamic programming cannot be applied to certain cost function due its drawback and to produce optimal multiple sequence alignment. We proposed sub-alignment refinement algorithm to overcome the problem of dynamic programming and impelmented this algorithm as a module of our MS Windows-based sequence alignment program.

• Journal of information and communication convergence engineering
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• v.10 no.1
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• pp.78-84
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• 2012

This paper presents a branch prediction algorithm and a 4-way set-associative cache for performance improvement of an embedded RISC core and a clock-gating algorithm with observability don’t care (ODC) operation to reduce the power consumption of the core. The branch prediction algorithm has a structure using a branch target buffer (BTB) and 4-way set associative cache that has a lower miss rate than a direct-mapped cache. Pseudo-least recently used (LRU) policy is used for reducing the number of LRU bits. The clock-gating algorithm reduces dynamic power consumption. As a result of estimation of the performance and the dynamic power, the performance of the OpenRISC core applied to the proposed architecture is improved about 29% and the dynamic power of the core with the Chartered 0.18 ${\mu}m$ technology library is reduced by 16%.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.137-138
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• 2006

In this paper, we study the algorithm for the multiport measurements using the 2port VNA(Vector network Analyzer). We explain the conversion algorithm which the open impedance to the matched impedance(50 ohm), and then we apply this algorithm to the 4 port VNA measurement. Finally, we discuss the reliability of this algorithm.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.27-33
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• 2012

In this paper, a new blind signal processing scheme for equalization in fading and impulsive-noise channel environments is introduced based on probability density functionmatching method and a set of Dirac-delta functions. Gaussian kernel of the proposed blind algorithm has the effect of cutting out the outliers on the difference between the desired level values and impulse-infected outputs. And also the proposed algorithm has relatively less sensitivity to channel eigenvalue ratio and has reduced computational complexity compared to the recently introduced correntropy algorithm. According to these characteristics, simulation results show that the proposed blind algorithm produces superior performance in multi-path communication channels corrupted with impulsive noise.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.277-278
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• 2017

Recently, many industrial instruments face the problem of protocol compatibility with the external monitoring and control system. This paper implemented a protocol conversion algorithm for industrial monitoring about communication Data. This algorithm is supported programmable method by user. we experimented the protocol conversion by communication gateway module using implemented algorithm, and obtained good results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.1075-1089
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• 2024

In this paper, the optimizations of multi-hop cooperative molecular communication (CMC) system in cylindrical anomalous-diffusive channel in three-dimensional enviroment are investigated. First, we derive the performance of bit error probability (BEP) of CMC system under decode-and-forward relay strategy. Then for achieving minimum average BEP, the optimization variables are detection thresholds at cooperative nodes and destination node, and the corresponding optimization problem is formulated. Furthermore, we use conjugate gradient (CG) algorithm to solve this optimization problem to search optimal detection thresholds. The numerical results show the optimal detection thresholds can be obtained by CG algorithm, which has good convergence behaviors with fewer iterations to achieve minimized average BEP compared with gradient decent algorithm and Bisection method which are used in molecular communication.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.560-565
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• 2018

The SPICE (Sparse Iterative Covariance-based Estimation) algorithm estimates the azimuth angle by applying a sparse recovery method to the covariance matrix in the time domain. In this paper, we show how the SPICE algorithm, which was originally formulated in the time domain, can be extended to the frequency domain. Furthermore, we demonstrate, through numerical results, that the performance of the proposed algorithm is superior to that of the conventional frequency domain algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4835-4855
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• 2018

In this paper, we study the sparse signal recovery that uses information of both support and amplitude of the sparse signal. A convergent iterative algorithm for sparse signal recovery is developed using Majorization-Minimization-based Non-convex Optimization (MM-NcO). Furthermore, it is shown that, typically, the sparse signals that are recovered using the proposed iterative algorithm are not globally optimal and the performance of the iterative algorithm depends on the initial point. Therefore, a modified MM-NcO-based iterative algorithm is developed that uses prior information of both support and amplitude of the sparse signal to enhance recovery performance. Finally, the modified MM-NcO-based iterative algorithm is used to estimate the time-varying sparse wireless channels with temporal correlation. The numerical results show that the new algorithm performs better than related algorithms.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.99-104
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• 2015

This paper proposes the RMMA (Region based Multiple Modulus Algorithm) algorithm that is possible to improving the performance of MMA adaptive equalization algorithm in order to the reduction of intersymbol interference occurs at the communication channel. In RMMA algorithm, the output constellation of equalizer are divided by 4 different regions in order to get the error signal for adapting the channel characteristic, and the small error signal is obtained by mapping each region to 4-QAM signal. The conversion effect of constant modulus from nonconstant modulus signal was obtained. In this paper, the adaptive equalization performance of proposed RMMA were evaluated comared to the present MMA. As a result of computer simulation, the convergence speed and residual quantity were improved in residual isi and MD. Especially the superiorities of robustness was confirm in SER performance compared to present MMA.