• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.249-250
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• 2006

Nowadays adaptive technique allows arrays of any geometry to be used with fast direction-of-arrival (DOA) estimators designed for linear arrays. So the interpolation of data from a given antenna array onto the output of a virtual array is needed before the direction finding technique is applied to the outputs of a uniform linear virtual array (ULVA). In this paper some superresoluntion methods are used to estimate DOA by best-fit transformation matrix T under different nonuniformly spaced array.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.133-142
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• 2011

Overhead facility design problem(OFDP) is one of the shortest rectilinear flow network problem(SRFNP)[4]. Genetic algorithm(GA), artificial immune system(AIS), population management genetic algorithm (PM) and greedy randomized adaptive search procedures (GRASP) were introduced to solve OFDP. A path matrix formed individual was designed to represent rectilinear path between each facility. An exchange crossover operator and an exchange mutation operator were introduced for OFDP. Computer programs for each algorithm were constructed to evaluate the performance of algorithms. Computation experiments were performed on the quality of solution and calculations time by using randomly generated test problems. The average object value of PM was the best of among four algorithms. The quality of solutions of AIS for the big sized problem were better than those of GA and GRASP. The solution quality of GRASP was the worst among four algorithms. Experimental results showed that the calculations time of GRASP was faster than any other algorithm. GA and PM had shown similar performance on calculation time and the calculation time of AIS was the worst.

• Industrial Engineering and Management Systems
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• v.11 no.4
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• pp.339-345
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• 2012

This research aims to formulate a mathematical model and develop an algorithm for solving a location problem in emergency medical service vehicle parking. To find an optimal parking location which has the least risk score or risk priority number calculated from severity, occurrence, detection, and distance from parking location for emergency patients, data were collected from Pratoom sub-district Disaster Prevention and Mitigation Center from October 2010 to April 2011. The criteria of risk evaluation were modified from Automotive Industry Action Group's criteria. An adaptive simulated annealing algorithm with multiple cooling schedules called multi-agent simulated quenching (MASQ) is proposed for solving the problem in two schemes of algorithms including dual agent and triple agent quenching. The result showed that the solution obtained from both scheme of MASQ was better than the traditional solution. The best locations obtained from MASQ-dual agent quenching scheme was nodes #5 and #133. The risk score was reduced 61% from 6,022 to 2,371 points.

• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.9-15
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• 2016

In this paper, we propose a smart HLS(HTTP Live Stream) platform with dynamic single buffering for the best transmission of adaptive video bit-rates. This smart HLS can optimizes the channel transition zapping-time with the monitoring of bandwidth between HLS server and OTT(Over The Top) client. This platform is designed through the control of video stream due to proper multi-bitrates and bandwidths. This proposed OTT can decode the live and VOD(Video On Demand) videos with the buffering of optimumal bitrate. And, the HLS can be cooperated with a smart OTT, and segmented for the m3u8 files of H.265 MPEG-2 TS(Transport Stream) videos. As a resullt, this single buffer based smart OTT can transmit optimal videos with the maximum data buffering according to the adaptive bit-rate depending on the network bandwidth efficiency and the decoded VOD video, too.

• Journal of Advanced Navigation Technology
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• v.7 no.1
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• pp.59-71
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• 2003

The channel scheduler is suggested the radio resource management method in order to provide service with guaranteeing fairness and throughput to the users who use limited wireless channel. Proportional fairness scheduling algorithm is the channel scheduler used in the AMC(Adaptive Modulation and Coding)/TDM system, and this algorithm increases the throughput considering the user's time fairness. In this paper is suggested the channel scheduler combining CDM scheme available in AMC/TDM/CDM system. Unlike the system which only uses TDM which provide the only one user at the same slot, this scheduler can service a lot of users since this uses the CDM scheme with multi-cord channel. At every moment, allocation of transmission power to multi-channel users is problematic because of CDM scheme. In this paper, we propose a water-filling scheduling algorithm to solve the problem. Water-filling fairness(WF2) scheduling algorithm watches the average channel environment. So, this modified method guarantees fairness for each user in terms of power and service time.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.514-520
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• 2015

Sidelobe canceller(SLC) requires main beam pattern(SUM beam) and auxiliary beam patterns for rejection of sidelobe noise jammer. For best performance of sidelobe noise jamming cancellation of adaptive SLC, gain dominant region of each auxiliary beam pattern shall not be overlapped one another in elevation/azimuth regions of sidelobe of main beam, and beam patterns of auxiliary channels should have low gains in regions of mainlobe of main beam. In the monopulse radar, the difference beam patterns for monopulse processing have these properties. This paper proposes the method using data from the difference channel for monopulse processing as data from auxiliary channel for sidelobe cancellation. For the proposed SLC, the results of simulation and performance analysis was presented. If the proposed method is used in the monopulse radar, SLC can be constructed by using basic SUM and difference channels without extra channel composition.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.157-162
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• 2010

In this paper, We propose that the adaptive cooperative relay transmission technique using closed-loop MIMO scheme for duplex communication system. As the mobility between relay and base station is little, closed-loop MIMO is better diversity gain than open-loop MIMO. At this time, more than one relaying terminals are included in one cooperative group to share their transmission and take precoding weight feedback. For minimization of throughput reduction caused by increasing feedback bits, we use codebook-based MRT that limit the number of feedback bits. Among the cooperative relay group, the best relays are selected from the base stataion and get the feedback. A protocol senarios are also proposed for this relay system.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.374-381
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• 2017

Concrete sleepers, installed on majority of railroad track in this nation can, if not maintained properly, threaten the safety of running trains. In this paper, an algorithm for automatically identifying cracks in a sleeper image, taken by high-resolution camera, is developed based on Adaboost, known as the strongest adaptive algorithm and most actively utilized algorithm of current days. The developed algorithm is trained using crack characteristics drawn from the analysis results of crack and non-crack images of field-installed sleepers. The applicability of the developed algorithm is verified using 48 images utilized in the training process and 11 images not used in the process. The verification results show that cracks in all the sleeper images can be successfully identified with an identification rate greater than 90%, and that the developed automatic crack identification algorithm therefore has sufficient applicability.

• ETRI Journal
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• v.30 no.5
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• pp.653-662
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• 2008

Arbitration of tag collision is a significant issue for fast tag identification in RFID systems. A good tag anti-collision algorithm can reduce collisions and increase the efficiency of tag identification. EPCglobal Generation-2 (Gen2) for passive RFID systems uses probabilistic slotted ALOHA with a Q algorithm, which is a kind of dynamic framed slotted ALOHA (DFSA), as the tag anti-collision algorithm. In this paper, we analyze the performance of the Q algorithm used in Gen2, and analyze the methods for estimating the number of slots and tags for DFSA. To increase the efficiency of tag identification, we propose new tag anti-collision algorithms, namely, Chebyshev's inequality, fixed adjustable framed Q, adaptive adjustable framed Q, and hybrid Q. The simulation results show that all the proposed algorithms outperform the conventional Q algorithm used in Gen2. Of all the proposed algorithms, AAFQ provides the best performance in terms of identification time and collision ratio and maximizes throughput and system efficiency. However, there is a tradeoff of complexity and performance between the CHI and AAFQ algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.3
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• pp.67-75
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• 2016

This paper investigates how artificial individuals with behavioral memory circuits adaptively evolve with respect to given environments on a cell-level simulation framework simulating artificial individuals. This makes it possible for us to analyse the advantages of artificial individuals with behavioral memory circuits against the simple artificial individuals that can do only simple reactions with respect to the environments and to know which advanced reactions are possible. In order to do this analysis, we experimented various tests on a specific prey pattern and examined the results. As a first experiment, we tested that artificial individuals with four memory steps competed against from those without memory step to those with three memory steps. Experimental results showed that the artificial individuals with four memory steps were superior to most others. However, artificial individuals with two memory steps were better than those with four memory steps. This was caused that the artificial individuals with two memory steps could evolve faster than those of four memory steps. In a second experiment that all types of artificial individuals are simultaneously evolved, the artificial individuals with two memory steps also showed the best result in the experiment. We could conclude that the artificial individuals with memory was better than those without memory and the best memory steps of artificial individuals were depended on the complexity of prey patterns.