IEICE Communications Express
Online ISSN : 2187-0136
ISSN-L : 2187-0136
Volume 4 , Issue 4
Showing 1-5 articles out of 5 articles from the selected issue
  • Yuta Endo, Yoshito Tezuka, Kazuyuki Saito, Koichi Ito
    Type: LETTER
    2015 Volume 4 Issue 4 Pages 105-110
    Published: 2015
    Released: April 03, 2015
    JOURNALS FREE ACCESS
    This study investigates the dielectric properties of coagulated biological tissues at 2.45 GHz in thermal treatments using microwave energy such as microwave coagulation therapy (MCT). These values are necessary to obtain accurate electromagnetic field or temperature distributions in numerical simulations of these treatments. This paper investigates the mechanism of changes in dielectric properties of biological tissues accompanying heat coagulation, by measuring the dielectric constants and water content ratios of tissues. Dielectric constants of heated biological tissues were observed to strongly depend on changes in their water content due to heat coagulation.
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  • Vorapong Suppakitpaisarn, Jean-François Baffier
    Type: LETTER
    2015 Volume 4 Issue 4 Pages 111-116
    Published: 2015
    Released: April 15, 2015
    JOURNALS FREE ACCESS
    In this paper, we propose an algorithm that outperforms an algorithm used for maximizing barrier coverage in battery harvesting sensor network proposed by DeWitt, Patt, and Shi. The previous work aims to maximize the robustness of the information transmission between two sensor nodes, while guarantee that the amount of energy harvested by each node is enough for its sufficient usage. The algorithm iteratively uses the maximum multiroute flow algorithm proposed by Kishimoto. When f is a max-flow value, it requires O(log f) iterations of Kishimoto’s algorithm to solve the problem. On the other hand, we propose an algorithm based on our previous method, called parametric multiroute flow. The running time of our algorithm asymptotically equals to one iteration of maximum multiroute flow. Our experimental results in random networks show that our algorithm can improve the computation time of the previous work by six times on average, when the number of nodes is 100 and the number of links is 1585.
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  • Sho Nakazawa, Shingo Matsuoka, Hiroyuki Otsuka
    Type: LETTER
    2015 Volume 4 Issue 4 Pages 117-122
    Published: 2015
    Released: April 15, 2015
    JOURNALS FREE ACCESS
    This paper proposes a state-of-the-art cell range expansion (CRE) technique that improves the user throughput performance for heterogeneous network (HetNet). The proposed adaptive control CRE provides different cell selection offsets (CSOs) for each piece of user equipment (UE). The proposed CRE’s aspects and algorithm are described in this paper through comparison with those of the conventional method that has a fixed CSO for operating all UEs. Computer simulation results such as average and 5-percentile user throughput based on LTE/LTE-Advanced standards are provided. We confirmed that the proposed adaptive control CRE can improve 5-percentile user throughput while maintaining the average user throughput. This will provide a remarkably effective solution for HetNet.
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  • Chin-Hao Liu, I-Fong Chen, Chia-Mei Peng, Zheng Hao, Ching-Wen Hsue
    Type: LETTER
    2015 Volume 4 Issue 4 Pages 123-129
    Published: 2015
    Released: April 28, 2015
    JOURNALS FREE ACCESS
    A novel patch antenna loaded with shorted-slots is proposed and analyzed in this article. The radiated patch antenna was chiseled two cross-slots, there are shorted-lines to be set at the middle- and cross-points of slots, which is designed to be operated at dual-ISM band (2.4 GHz and 5.8 GHz bands). A prototype of the proposed antenna with 63 mm in length, 7.6 mm in height and 72 mm in width is fabricated and experimentally investigated. The experimental results indicate that the VSWR ≦ 2.5 bandwidths achieved were 13.3% and 15.9% at 2.45 GHz and 5.5 GHz, respectively. There is good agreement between the simulated and measured results.
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  • Yoshiaki Maneyama, Masashi Tadokoro, Daisuke Murayama, Manabu Yoshino, ...
    Type: LETTER
    2015 Volume 4 Issue 4 Pages 130-135
    Published: 2015
    Released: April 28, 2015
    JOURNALS FREE ACCESS
    In recent years, with the popularization of factory automation and large-scale sensor-actuator networks, networked control systems (NCSs) over optical networks have been attracting considerable research interest. In NCSs, a delay compensator, which includes an average round-trip time (RTT) model, is implemented to improve stability and performance. However, energy-efficient networks based on cyclic sleep techniques can induce rate-dependent fluctuations in the average downstream queuing delay or the average RTT for periodically generated NCS traffic. The fluctuations result in a mismatch between the average RTT model and the actual RTT, which in turn results in destabilization and performance degradation. This letter proposes sleep period randomization methods for energy-efficient Ethernet passive optical networks (EPONs) to prevent rate-dependent fluctuations in the low-rate range. Simulation results are presented to verify the effectiveness of the proposed methods.
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