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FFTと連続ウェーブレット変換法を用いた同期位相計測に基づく電力システムのモード検出とダンピング推定
Full text link九州工業大学博士学位論文（要旨）学位記番号：工博甲第413号 学位授与年月日平成28年3月25
The Online Publication of the Doctoral Thesis and Copyright
Full text link平成28年度博士論文インターネット公表と著作権, 日時・場所：平成28年7月4日（月）九州工業大学附属図書館AVホール,7月15日（金）九州工業大学若松キャンパス大講義
マルチホップ無線ネットワークの特性解析に関する研究
Full text link九州工業大学博士学位論文 学位記番号:情工博甲第309号 学位授与年月日:平成28年3月25日1 Introduction||2 Impact of Transceiver Hardware Impairments on Cognitive Network||3 Case study: Two-Way Cognitive Relay in RF Energy HarvestingWireless Sensor Network||4 Soft Information Relaying Protocol||5 Overall Conclusion and FutureWorkWireless communication has been considered as the most efficient mean of data
transmission. We have been witnessed the breakthrough of wireless communication
era in many manifolds, such as speech, coverage area, and stability. However,
frequency bands, the resource to convey information wirelessly, are limited and expensive
to be granted usage licenses.
Attaining the goals of ubiquitous wireless devices will require the future wireless
networks stepping forward to overcome the scarcity and expensiveness of wireless
frequency bands. Thus, the future wireless networks should evolve to utilize wireless
frequencies more efficiently, such as cognitive relay network where non-license
users are able to transmit data in the same frequency band that officially allocated to
primary users. Subsequently, the transmit power of users in a cognitive network is
limited and the performance is vulnerable to impairments of transceiver hardware.
This dissertation aims to analyze the performance of the cognitive relay network
under the impact of transceiver hardware impairments. A case study of two-way
cognitive relay network is given for further investigate the impact of transceiver
hardware impairments on end-to-end outage performance and throughput. Furthermore,
we provide a new relaying scheme in order to lessen the impact of transceiver
hardware impairment and further boost the system performance. For the purposes,
this dissertation is organized into five (5) chapters.
Chapter 1: Introduction. In this chapter, multihop wireless networks and the performance
metrics are overviewed. In particular, the relay networks and cognitive relay
networks are presented. Moreover, the general model of the practical transceiver
hardware impairment is detailed for further analysis.
Chapter 2: The impact of transceiver hardware impairments on cognitive relay networks.
By using the general hardware impairment model for the received signal, the
closed forms of outage probability of the relay network with decode-and-forward
(DF) and amplify-and-forward (AF) under the impact of transceiver hardware imperfection
are derived. Based on these results, we provide further discussion on
transceiver hardware selection guideline.
Chapter 3: Case study: two-way cognitive relaying in energy harvesting wireless
sensor networks. A two-way relay wireless sensor network equipped with
RF energy harvesting node is introduced. This network is aimed to be implemented
in hazardous or remote areas where power supply for the relay node is
difficult to maintain. In this chapter, we consider four configurations of the network
with formed by combining two bidirectional relaying protocols and two wireless
power transfer policies. The detailed performance analysis of outage probability
and throughput of the case-study network with four configurations are presented.
Based on the analysis, we provide performance comparison between the four and
suggest the network configuration with the best performance.
Chapter 4: Soft information relaying protocol. The soft information relaying protocol
is proposed and analyzed. The analysis shows that this relaying protocol can
gradually reduce the impact of transceiver hardware impairment on cognitive relay
networks. Hence, soft relaying protocol is considered as a solution for cognitive
relay network with cost-effective wireless transceiver devices.
Chapter 5: Overall conclusion. An overall summary of the works presented in
the above is provided in this chapter. Moreover, the future related work is also
discussed.
The results in this dissertation acknowledge the impact of transceiver hardware impairment
by presenting the reduction of outage probability and throughput of the
cognitive relay network. It puts forward the consideration of including the impact
of transceiver hardware impairments on wireless network performance analysis, especially
for the cognitive networks of which the transmit power is limited.
Furthermore, a new relaying protocol, namely soft information relaying protocol,
is proposed as a solution to lessen the impact of transceiver hardware impairment.
The analysis shows that the impact of transceiver hardware impairment in cognitive
relay network is reduced in compared to conventional relaying schemes.
As a final point, we have provided a full picture of performance analysis for the
cognitive relay network under the impact of transceiver hardware imperfection and
the solution to reduce the performance loss by applying soft information relaying
scheme. This research would contribute to boost the development of cognitive relay
networks where frequency bands are used more efficiently
Changes in Diad Sequence Distribution by Preferential Chain Scission during Thermal Hydrolysis of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)
Full text linkA Text Selection Method for Tablet Devices using Japanese Morphological Analysis
No full textタブレット端末やスマートフォンにおけるソフトウェアキーボードによる文字入力は，物理的なキーボードによる文字入力に比べて負荷が高い．そのため，画面に表示されている文字列を選択し，コピー&ペーストして再利用することが頻繁に行われる．しかし従来のタブレット/スマートフォン用 OS における文字列範囲選択手法は選択対象文の文法や文脈を考慮して設計されていない．本研究では，日本語文字列をタブレット端末やスマートフォンで効率良く選択するための，日本語形態素を考慮した文字列範囲選択手法を提案し，その有効性を確認する．文字単位，単語単位，およびひらがな１文字の助詞を直前の単語と連結する方式（単語＋助詞単位）3 条件での被験者実験を行い，一元配置の分散分析を行った結果，上記 3 手法の作業時間の平均値に有意差が認められた．また文字単位と単語単位を動的に切り替える手法について被験者実験を行い，分散分析を行った結果，選択範囲が単語区切りのタスクにおいては作業時間を減少する傾向がみられた．
Conventional copy-and-paste technique for touch screen devices utilizes region handles to specify text snippet. The region handles appear so as to select the initially tapped word, and the user controls the region handles. Most of the text-selection task is performed at the boundary of words, however, the minimum movement unit of the region handle is still a character. We propose a context-sensitive text-selection method for the tablet OSs using Japanese morphological analysis. For the initial consideration, we investigated a word grouping method that meant a word as a minimum movement unit. From our experiment, we confirmed that the word grouping method can significantly reduce the text-selection time, and the word grouping size significantly affects the time. Also we tested a flexible word grouping method that changes the minimum movement unit by considering the movement speed of the region handles. The result showed a tendency of reducing the text-selection time, if target regions ended with the boundary of words
