• Title/Summary/Keyword: ACO

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Effects of Space Charge on Conduction Mechanism in Low density Polyethylene with Air Gap (공기층을 가진 저밀도 폴리에틸렌에서의 전도특성과 공간전하 효과)

  • Park, H.W.;Kwon, Y.H.;Jeon, S.I.;HwangBo, S.;Han, M.K.
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1438-1440
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    • 1998
  • In this work, simultaneous measur of space charge and conduction current was c out in LDPE with air gap by Pulsed-Electro-Aco Method. Also, effect of long time charging at con electric field on the formation of space charge conduction was investigated. From the experim results. we knew that the homo space charge formed near the dielectric surfaces and moving the bulk of dielectric as the electric field elevated. This was related with the deep traps b carriers and de trapping by Poole-field lowering conduction current was coincident with the Pool emission. From the long time charging experimen obtained the results that the negative space was moving into the dielectric bulk as the cha continued and the positive space charge accumulated at upper surface of LDPE.

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Adaptive k-means clustering for Flying Ad-hoc Networks

  • Raza, Ali;Khan, Muhammad Fahad;Maqsood, Muazzam;Haider, Bilal;Aadil, Farhan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.14 no.6
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    • pp.2670-2685
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    • 2020
  • Flying ad-hoc networks (FANETs) is a vibrant research area nowadays. This type of network ranges from various military and civilian applications. FANET is formed by micro and macro UAVs. Among many other problems, there are two main issues in FANET. Limited energy and high mobility of FANET nodes effect the flight time and routing directly. Clustering is a remedy to handle these types of problems. In this paper, an efficient clustering technique is proposed to handle routing and energy problems. Transmission range of FANET nodes is dynamically tuned accordingly as per their operational requirement. By optimizing the transmission range packet loss ratio (PLR) is minimized and link quality is improved which leads towards reduced energy consumption. To elect optimal cluster heads (CHs) based on their fitness we use k-means. Selection of optimal CHs reduce the routing overhead and improves energy consumption. Our proposed scheme outclasses the existing state-of-the-art techniques, ACO based CACONET and PSO based CLPSO, in terms of energy consumption and cluster building time.

Swarm Intelligence-based Power Allocation and Relay Selection Algorithm for wireless cooperative network

  • Xing, Yaxin;Chen, Yueyun;Lv, Chen;Gong, Zheng;Xu, Ling
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.3
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    • pp.1111-1130
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    • 2016
  • Cooperative communications can significantly improve the wireless transmission performance with the help of relay nodes. In cooperative communication networks, relay selection and power allocation are two key issues. In this paper, we propose a relay selection and power allocation scheme RS-PA-PSACO (Relay Selection-Power Allocation-Particle Swarm Ant Colony Optimization) based on PSACO (Particle Swarm Ant Colony Optimization) algorithm. This scheme can effectively reduce the computational complexity and select the optimal relay nodes. As one of the swarm intelligence algorithms, PSACO which combined both PSO (Particle Swarm Optimization) and ACO (Ant Colony Optimization) algorithms is effective to solve non-linear optimization problems through a fast global search at a low cost. The proposed RS-PA-PSACO algorithm can simultaneously obtain the optimal solutions of relay selection and power allocation to minimize the SER (Symbol Error Rate) with a fixed total power constraint both in AF (Amplify and Forward) and DF (Decode and Forward) modes. Simulation results show that the proposed scheme improves the system performance significantly both in reliability and power efficiency at a low complexity.

A Hybrid PAPR Reduction Scheme for Optical Wireless OFDM Communication Systems

  • Abdulkafi, Ayad Atiyah;Alias, Mohamad Yusoff;Hussein, Yaseein Soubhi;Omar, Nazaruddin;Salleh, Mohd Kamarulzamin Bin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.3
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    • pp.1136-1151
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    • 2018
  • This paper proposes a new hybrid scheme to decrease the high peak to average power ratio (PAPR) of optical orthogonal frequency division multiplexing (OFDM) signals in visible light communication (VLC) systems. The PAPR causes nonlinear signal distortions and high power requirements for the VLC transmitter (light emitting diode, LED). The proposed method is applicable for both direct current-biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM). In the proposed scheme, the PTS method is firstly modified to fit both optical OFDM approaches transmission and then combined with signal clipping method for further PAPR reduction and bit error rate (BER) improvement of the VLC system. The performance of hybrid scheme has been evaluated and compared with the original OFDM based VLC system, conventional PTS and clipping methods. The results show that the hybrid scheme outperforms other methods in terms of both the PAPR reduction and BER performance.

Systematic Studies on the Freshwater Goby, Rhinogobius Species (Perciformes, Geobiidae) III. Geographic Variation and Subspecific Differentiation in Rhinogobius giurinus, with a Comment on Genetic Relationships among Four Species of the Genus Rhinogobius in Korea

  • Kim, Jong-Bum;Kim, Jae-Heup;Yang, Suh-Yung
    • Animal cells and systems
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    • v.1 no.4
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    • pp.529-534
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    • 1997
  • Genetic and morphological variations of Rhinogobius giurinus were surveyed. Populations of R.giurinus were clearly divided into two forms (Form-A and Form-B). Starch gel variation of this species. Three loci (Aco, Mpi, aGpd) out of 27 showed fixed allelic differences between Form-A and Form-B and they are well differentiated from each other genetically (Rogers' S=0.871). These two forms, moreover, are found to be allopatric in distribution and morphologi cally different in body length and caudal fin color pattern. Therefore, they are considered as two distinct taxa of subspecific rank. In addition, the genetic relationships among 5 taxa within 4 species of the genus Rhinogobius were investigated. Three species of the Rhinogobius brunneus complex (R.sp. OR, R. sp. CB and R. sp. CO) are well differentiated from each other genetically and two taxa of R. giurinus are genetically divergent from three species of the Rhinosotius brunneus complex (average Nei's D=0.603, average Rogers'=0.534).

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A Hybrid Parallel Genetic Algorithm for Reliability Optimal Design of a Series System (직렬시스템의 신뢰도 최적 설계를 위한 Hybrid 병렬 유전자 알고리즘 해법)

  • Kim, Ki-Tae;Jeon, Geon-Wook
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.33 no.2
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    • pp.48-55
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    • 2010
  • Reliability has been considered as a one of the major design measures in various industrial and military systems. The main objective is to suggest a mathematical programming model and a hybrid parallel genetic algorithm(HPGA) for the problem that determines the optimal component reliability to maximize the system reliability under cost constraint in this study. Reliability optimization problem has been known as a NP-hard problem and normally formulated as a mixed binary integer programming model. Component structure, reliability, and cost were computed by using HPGA and compared with the results of existing meta-heuristic such as Ant Colony Optimization(ACO), Simulated Annealing(SA), Tabu Search(TS) and Reoptimization Procedure. The global optimal solutions of each problem are obtained by using CPLEX 11.1. The results of suggested algorithm give the same or better solutions than existing algorithms, because the suggested algorithm could paratactically evolved by operating several sub-populations and improving solution through swap and 2-opt processes.

Genetic Diversity and Speciation of Rana rugosa (Amphibia; Ranidae)

  • Yang, Suh-Yung;Min, Mi-Sook;Kim, Jong-Bum;Suh, Jae-Hwa;Kang, Young-Jin
    • Animal cells and systems
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    • v.4 no.1
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    • pp.23-30
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    • 2000
  • Horizontal starch gel electrophoresis for 29 populations (n=543) of the wrinkled frog, Rana rugosa, from Korea and Japan was peformed to assess the degree of genic variation and genetic diversity, and to understand the biogeographic pattern of distribution and speciation. A sum of 22 presumptive loci was screened from 17 enzymes and general proteins. Four loci, Aco, Est-3, Me-2, and Pgm, demonstrated high levels of polymorphism. The degree of average genetic variation of R. rugosa was P=22.7% (9.1-40.9%), Ho=0.086 (0.048-0.165) and He=0.090 (0.042-0.168). In the south-eastern region of the Korean peninsula (Chongsong, Yongchon, Ulsan, Kyongju, Pohang, yongdok and Ulchin), a few unique alleles in the Mpi locus were detected and their biogeographic implications were considered. The degree of genetic differentiation among the Korean populations was moderate (S=0.900), whereas the degree of genetic diversity between Korean and Japanese populations was notably high (S=0.687, D=0.293). This result corresponds with the data obtained by the mitochondrial cytochrome b gene sequence (Lee et al., 1999) suggesting that the Korean and Japanese R. rugosa might have evolved a specific level of genetic differentiation since their geographic isolation.

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Improved Heterogeneous-Ants-Based Path Planner using RRT* (RRT*를 활용하여 향상된 이종의 개미군집 기반 경로 계획 알고리즘)

  • Lee, Joonwoo
    • The Journal of Korea Robotics Society
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    • v.14 no.4
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    • pp.285-292
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    • 2019
  • Path planning is an important problem to solve in robotics and there has been many related studies so far. In the previous research, we proposed the Heterogeneous-Ants-Based Path Planner (HAB-PP) for the global path planning of mobile robots. The conventional path planners using grid map had discrete state transitions that constrain the only movement of an agent to multiples of 45 degrees. The HAB-PP provided the smoother path using the heterogeneous ants unlike the conventional path planners based on Ant Colony Optimization (ACO) algorithm. The planner, however, has the problem that the optimization of the path once found is fast but it takes a lot of time to find the first path to the goal point. Also, the HAB-PP often falls into a local optimum solution. To solve these problems, this paper proposes an improved ant-inspired path planner using the Rapidly-exploring Random Tree-star ($RRT^*$). The key ideas are to use $RRT^*$ as the characteristic of another heterogeneous ant and to share the information for the found path through the pheromone field. The comparative simulations with several scenarios verify the performance of the improved HAB-PP.

DEVELOPMENT OF AUTONOMOUS QoS BASED MULTICAST COMMUNICATION SYSTEM IN MANETS

  • Sarangi, Sanjaya Kumar;Panda, Mrutyunjaya
    • International Journal of Computer Science & Network Security
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    • v.21 no.8
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    • pp.342-352
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    • 2021
  • Multicast Routings is a big challenge due to limitations such as node power and bandwidth Mobile Ad-hoc Network (MANET). The path to be chosen from the source to the destination node requires protocols. Multicast protocols support group-oriented operations in a bandwidth-efficient way. While several protocols for multi-cast MANETs have been evolved, security remains a challenging problem. Consequently, MANET is required for high quality of service measures (QoS) such infrastructure and application to be identified. The goal of a MANETs QoS-aware protocol is to discover more optimal pathways between the network source/destination nodes and hence the QoS demands. It works by employing the optimization method to pick the route path with the emphasis on several QoS metrics. In this paper safe routing is guaranteed using the Secured Multicast Routing offered in MANET by utilizing the Ant Colony Optimization (ACO) technique to integrate the QOS-conscious route setup into the route selection. This implies that only the data transmission may select the way to meet the QoS limitations from source to destination. Furthermore, the track reliability is considered when selecting the best path between the source and destination nodes. For the optimization of the best path and its performance, the optimized algorithm called the micro artificial bee colony approach is chosen about the probabilistic ant routing technique.

A Metaheuristic Approach Towards Enhancement of Network Lifetime in Wireless Sensor Networks

  • J. Samuel Manoharan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.17 no.4
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    • pp.1276-1295
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    • 2023
  • Sensor networks are now an essential aspect of wireless communication, especially with the introduction of new gadgets and protocols. Their ability to be deployed anywhere, especially where human presence is undesirable, makes them perfect choices for remote observation and control. Despite their vast range of applications from home to hostile territory monitoring, limited battery power remains a limiting factor in their efficacy. To analyze and transmit data, it requires intelligent use of available battery power. Several studies have established effective routing algorithms based on clustering. However, choosing optimal cluster heads and similarity measures for clustering significantly increases computing time and cost. This work proposes and implements a simple two-phase technique of route creation and maintenance to ensure route reliability by employing nature-inspired ant colony optimization followed by the fuzzy decision engine (FDE). Benchmark methods such as PSO, ACO and GWO are compared with the proposed HRCM's performance. The objective has been focused towards establishing the superiority of proposed work amongst existing optimization methods in a standalone configuration. An average of 15% improvement in energy consumption followed by 12% improvement in latency reduction is observed in proposed hybrid model over standalone optimization methods.