Internet of Things (IoT) is developing rapidly with wider application fields. IoT’s main infrastructure is called a wireless sensor network (WSN). Hence, WSN must be able to operate on various network models. Multi-hop clustering is considered a solution for adapting to various network sizes. Multi-hop clustering must be designed to maintain the balance of energy consumption between nodes, and many algorithms have been proposed for this purpose. However, most clustering algorithms are designed with the assumption that the network is a two-dimensional plane. In many applications, WSN is more appropriately modeled as a three-dimensional (3D) network, for example, the WSN application for structural health monitoring or underwater wireless sensor networks. Here, a clustering algorithm for 3D-WSN is proposed. This algorithm is developed based on an analysis of the balance of energy consumption, such that the network lifetime is expected to be longer. The main novelty of our algorithm is the utilization of multi-hop layered transmission. From the simulation, the performance of the proposed algorithm exhibits a good energy balance compared to an un-balanced analysis.

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In wireless communication, it is hard to set the optimal route between a source and a destination through relays, since for optimal relaying, the system operator should know all channel conditions from a source to a destination through relays and determine the path with all channel conditions. In this letter, a multiple relay selection strategy is proposed for the reliability of transmission. The proposed strategy establishes a relaying route to a destination and provides an efficient relay selection process regardless of all channel conditions.

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To improve the BER performance of the conventional cooperative communication, this letter proposes an efficient method for the reliability, and it uses hierarchical modulation that has both the high priority (HP) layer and the low priority (LP) layer. To compensate more reliable transmission, the proposed method uses the error correction capability of Reed-Solomon (RS) codes additionally. The simulation results show that the proposed method can transmit data more reliably than the basic RS coded decode-and-forward (DF) method.

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The future wireless mobile communication networks are expected to provide seamless wireless access and data exchange to mobile users. In particular, it is expected that the demand for ubiquitous data exchange between mobile users will increase with the widespread use of various wireless applications of the intelligent transportation system (ITS) and intelligent vehicles. Mobile ad hoc networks (MANETs) are one of the representative research areas pursuing the technology needed to satisfy the increasing mobile communication requirements. However, most of the works on MANET systems do not take into account the continuous and dynamic changes of nodal mobility to accommodate system design and performance evaluation. The mobility of nodes limits the reliability of communication between the source and the destination node since a link between two continuously moving nodes is established only when one node enters the transmission range of the other. To alleviate this problem, mobile relay has been studied. In particular, it is shown that relay selection is an efficient way to support nodal mobility in MANET systems. In this paper, we propose a mobility-based relay selection algorithm for the MANET environment. Firstly, we define the lifetime as the maximum link duration for which the link between two nodes remains active. Therefore, the lifetime indicates the reliability of the relay link which measures its capability to successfully support relayed communication when requested by the source node. Furthermore, we consider a series of realistic scenarios according to the randomness of nodal mobility. Thus, the proposed algorithm can be easily applied in practical MANET systems by choosing the appropriate node mobility behavior. The numerical results show that the improved reliability of the proposed algorithm's relayed communication is achieved with a proper number of mobile relay nodes rather than with the conventional selection algorithm. Lastly, we show that random mobility of the individual nodes enhances reliability of the network in a sparse network environment.

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In classical routing protocols, geographical distances/locations are typically used as the metric to select the best route, under the assumption that shorter distances exhibit lower energy consumption and nodes within the communication range of the sender can receive packets with a certain success probability. However, in underwater acoustic sensor networks (UASNs), sound propagation in the ocean medium is more complex than that in the air due to many factors, including sound speed variations and the interaction of sound waves with the sea surface and floor, causing the sound rays to bend. Therefore, propagation of sound is anisotropic in water, and may cause a phenomenon called shadow zone where nodes in the communication range of the sender cannot hear any signal. This renders conventional routing protocols no longer energy-efficient. In this paper, we make use of the ray-model to account for the environment-dependent behavior of the underwater channel, re-define nodes' one-hop neighbors based on signal attenuation rather than geographical distance, and design a distributed energy-efficient routing protocol for UASNs. Results show that our ray-model-based routing policy consistently outperforms the shortest path policy, and performs very close to the optimal one in several scenarios.

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The group-level findings in classical experimental studies of communication networks may be considered the out come of some complex psychological mechanisms. Alternatively, they might ve mere reflections of the task structures of communication networks, and could be obtained even if human subjects reacted 'automatically.' In order to resolve such ambiguity, a computer simulation model was constructed, separating the task structures and the artificial subjects' response characteristics. This simulation model roughly reproducted the findings of communication network studies in terms of the following: (a) the increased efficiency of non-centralized networks relative to the Wheel network in the case of high task-difficulty; (b) role-structures in the respective networks; (c) the positions of 'leaders' in several networks research can be understood to be reflecting the task structures of the experimental situaitons to some degree. Implications and limitaions of this study are discussed.

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The cohesive, or softening-melting zone plays a critical role in determining blast furnace performance and stability. The effect of changes in the permeability of softening-melting ore and the subsequent distribution of gases and liquids around the anisotropic packing structure of coke and ore layers in this region must be understood before the blast furnace can be adequately modelled. This study aimed to address issues related to cohesive zone formation through low-temperature experimentation. Two investigations of meltdown behaviour were performed, classified according to geometrical characteristics. The first ‘flat layer meltdown’ investigation examined the softening-melting of flat cohesive layers extending across the furnace diameter. This configuration matched that used in high-temperature softening-melting tests. The second ‘single layer meltdown’ investigation concentrated on a single cohesive layer embedded in a permeable packing. This configuration can be likened to a single cohesive layer in a permeable cohesive zone, where gas is able to bypass ore through intermediate coke slits as permeability is lost. The meltdown of flat cohesive zones was characterised by variability and gas channelling, promoting furnace instability and preventing accurate modelling. The meltdown of single layers demonstrated the possibility of structural variation between the surface and core, and the change in contribution of convection and conduction to heating.

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日本における大学2年生のフランス語コミュニケーションのクラスは、特殊な諸問題を起こす。学生が自立的にまだ会話ができないことがその原因である。本稿では、どうやって、学生に「概要的」かつ「簡略的」に喋るように指導することで、その問題を解決ができるかを考える。外国語で話すとき、自分の言語とは異なり会話に戦略が必要となる。その戦略を「描写」の練習を使って学生に身をつけさせるのである。

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In this paper, we investigate the antenna and node selection issues for amplify-and-forward (AF) and decode-and-forward (DF) multi-antenna relay networks in correlated channels. Based on the channel statistics, optimal selection criteria for antenna and relay node are derived jointly, aiming to maximize the ergodic capacity. Instantaneous channel knowledge-based selection schemes, motivated by traditional antenna selection algorithms, are investigated as well. It is shown that the proposed node selection schemes derived from antenna selection on relay nodes are feasible and effective in relay systems. Statistical selection shows considerable capacity gain compared to full complexity scheme and random selection strategy in AF mode, while instantaneous selection performs better in DF relaying. Furthermore, the proposed schemes are shown to be robust to channel estimation errors due to their correlation-oriented nature.

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Mettant en question le mot <<partage>>, qui prend une place tres importante dans le lexique nancien, nous essayons d'ouvrir un nouvel horizon pour la pensee a propos de la <<communaute>>. Il s'agit de la <<communaute>> non pas au sen sociologique politique, ni anthropologique, mais au sens ontologique. C'est celle qui expose ou s'expose l'<<etre>> de nous-existants, c'est-a-dire le <<Mit-Dasein>>, le sens meme de notre existence telle qu'exprime par Heidegger. Cet <<etre>>, Nancy l'exprime toujours dans des locutions verbales telles qu'<<etre-en-commun>>, <<etre-ensemble>>, <<etre-les-uns-avec-les-autres>>. Notre existence devraitelle etre toujours verbale (transitive), c'est-a-dire sans arret en mouvement, et co-existante avec les autres existants? C'est le mot <<partage>> qui concoit et exprime en soi le rapport de l'<<etre>>, ou le rapport comme <<etre>>. Il s'expose dans ces deux sens strategiques, en relayant la deconstruction derridienne. D'abord, il deconstruit le monde meme, constitue par la pensee de <<division>> (un sens meme du <<partage>>) typiquement occidentale, dans ses deux mouvements reciproques et contraires, c'est-a-dire <<diviser>> toutes choses, et puis les reconstruire dans un systeme solide avec et sur des choses in-divisibles (entelechie, element, substance, etc...) Selon cette penseela, nous sommes censes etre <<in-dividus>>. Voila la pensee qui doit etre deconstruite par le mot de <<partage>>. Deuxiemement, Nancy doit deconstruire le sens meme du <<partage>> concu au sens orthodoxe du mot. Ce mot exprime en soi deux sortes de rapport (ou de role) des existants entre eux, c'est-a-dire en <<conserver (ou )>> tout ce qu'il y a ou tout ce qu'il y avait, et y <<participer>>. Nancy deconstruit ces rapports en (re-)interpretant la pensee platonicienne, telle qu'elle apparait dans l'Ion, et donc la pensee de l'Idee avant tout. Selon lui, le rapport des existants et de l'Idee, compris ordinairement, doit etre renverse, en ce sens meme que le rapport confie au mot de <<methexis>>, doit etre compris dans le mouvement de <<Descente>>, au lieu d'etre pris dans un mouvement qui nous amene jusqu'a l'au-dela, dans une ascension permanente vers l'Idee (le mouvement de <<Remontee>>). Somme toute, si la pensee platonicienne consiste dans le mouvement de <<Remontee>>, le <<methexis>> signifie necessairement comme suite: <<participer aux idees (a l'Idee)>>, en meme temps que <<participer des idees>>. Chaque existant n'est alors qu'un constituant (parmi d'autres) de l'ensemble (des idees). Mais, si le mouvement s'inverse, il nous faut le concevoir comme le fait de <<se situer dans l'ensemble des idees comme etant un constituant-l'ensemble>>, (en japonais <<与かる>>, et non comme un constituant de l'ensemble, prenant le relais des idees, (en japonais <<預かる>>). Nancy etablit ce rapport a travers le mot <<partage>>, semble-t-il. Voici la maniere dont nous existons ou co-existons dans le monde reel, ou de <<communaute>>, et le sens de l'existence exprime dans la locution verbale <<etre-en-commun>>.

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教育文化に関する研究とその知識は、学習者をその文化的帰属によってカテゴリー化する恐れがあるとして、言語文化教育における個人主義的アプローチの支持者から批判されている。本研究の目的は、多文化環境での教育実践における教師の文化的知識の役割についてのインタビュー調査を通して、この批判の妥当性を検討するものである。日本の大学で教えているネイティブFLE教師に対して行ったインタビュー結果の分析から、学習者の教育的習慣に関する文化的知識は、適応への慎重さと好意的理解に基づいた教師倫理の一部を形成しているということが明らかになった。この分析結果は、異文化間現象において文化的背景の理解よりも個人の理解を優先させることに対して、異論を唱え、メタ文化的アプローチの必要性を支持するものとなった。

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