A Novel Co-operative Channel Assignment Scheme for Indoor Base Stations

This paper presents a co-operation technique ofchannel assignment (CA) for indoor base stations (BSs). IndoorBSs are most of the time deployed by users in an ad-hoc mannerwhich makes prior network planning by network operatorsimpossible. If the same pool of radio resources (e.g channels) isused by close BSs, co-operation between these BSs is vital forresolving problems such as interference. In the proposed scheme,femtocell base station (FBS), which is a typical example of indoorBS, is considered. FBSs in close proximity exchange UE-assisted(User Equipment) measured reference power information, andbased on individual position of each FBS, inter-BS interaction isused to form clusters. In each cluster, the cluster-head (CH) useschannel assignment tables to assign channel resources to clustermembers(CMs) in a distributed manner. This scheme helps toensure that the interest of neighbor BSs is always consideredwhenever a BS makes use of the available network resources.Our simulation results show that co-operative CA using a clusterbasedapproach yields higher average user throughput thanautonomous channel selection by individual BSs

Supercharging the APGAS Programming Model with Relocatable Distributed Collections

In this article we present our relocatable distributed collections library. Building on top of the AGPAS for Java library, we provide a number of useful intra-node parallel patterns as well as the features necessary to support the distributed nature of the computation through clearly identified methods. In particular, the transfer of distributed collections' entries between processes is supported via an integrated relocation system. This enables dynamic load-balancing capabilities, making it possible for programs to adapt to uneven or evolving cluster performance. The system we developed makes it possible to dynamically control the distribution and the data-flow of distributed programs through high-level abstractions. Programmers using our library can therefore write complex distributed programs combining computation and communication phases through a consistent API. We evaluate the performance of our library against two programs taken from well-known Java benchmark suites, demonstrating superior programmability, and obtaining better performance on one benchmark and reasonable overhead on the second. Finally, we demonstrate the ease and benefits of load-balancing and on a more complex application which uses the various features of our library extensively.Comment: 23 pages 8 figures Consult the source code in the GitHub repository at https://github.com/handist/collection

An Efficiency Degradation Model of Power Amplifier and the Impact against Transmission Power Control for Wireless Sensor Networks

Abstract—To extend an available period of wireless sensor networks, transmission power control is regarded as one of the promising schemes. In most of the previous studies on the transmission power control, it is assumed that a transmitter has power consumption of O(dn), where d and n denote a maximum communication distance and a pass loss factor. This assumption would substantially hold under the condition that the transmission efficiency is always constant at any transmission power (efficiency-fixed model). In practice, however, the trans-mission efficiency degrades as the transmission power is reduced. We analytically verify that an actual power amplifier with the efficiency degradation has a power consumption of O(dr), where n/2.8 ≤ r ≤ n/2 (efficiency-degradation model). The efficiency-degradation model gives the negative impact against the transmission power control. Index Terms—Wireless sensor network, transmission power control, transmission efficiency, pass loss factor. I

Important comments on KERMA factors and DPA cross-section data in ACE files of JENDL-4.0, JEFF-3.2 and ENDF/B-VII.1

We have studied reasons of differences of KERMA factors and DPA cross-section data among nuclear data libraries. Here the KERMA factors and DPA cross-section data included in the official ACE files of JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 are examined in more detail. As a result, it is newly found out that the KERMA factors and DPA cross-section data of a lot of nuclei are different among JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 and reasons of the differences are the followings: 1) large secondary particle production yield, 2) no secondary gamma data, 3) secondary gamma data in files12–15 mt = 3, 4) mt = 103–107 data without mt = 600 s–800 s data in file6. The issue 1) is considered to be due to nuclear data, while the issues 2)-4) seem to be due to NJOY. The ACE files of JENDL-4.0, ENDF/B-VII.1 and JEFF-3.2 with these problems should be revised after correcting wrong nuclear data and NJOY problems

コウトウ キョウイク カイカク ノ ソウゴ コウイ ブンセキ : ビデオ エスノグラフィー ケンキュウ ノ ネライ ト コウガクブ トシ コウガク エンシュウ ノ ジッサイ

ビデオエスノグラフィーは、当事者的知識を十分に摂取しながら行うビデオ分析であり、我々は この方法で、高等教育改革の現場を研究した。生涯学習社会の到来を受けて、日本の高等教育は現在第 2 次世界大戦直後以来の改革期にある。すなわち、「知識」より「生涯学習能力」の獲得を志向した、 自発性を尊重するような様々な取り組みがなされ始めている。この高等教育の現場に対し、ワークプレ ース研究を行った。Ｂ大学工学部都市工学演習α班を分析対象とした調査の結果、①演習の課題解釈に は「従来の指標の相対化の要求の程度」を巡って２つの解釈があり得たこと、②班内にはその２種類の 解釈に対応した葛藤・対立的相互行為が存在したこと、③にもかかわらず、班内葛藤を生きる当事者が ともに専門性（「都市工学」）を志向していたこと、④したがって、課題理解のいかんにかかわらず、 班活動の全体が「都市工学演習」と呼び得るものになっていたこと、⑤その一方で、最終審査会場（ジ ュリー）ではこの２重性が十分レリバントなものとして浮かび上がって来ていなかったこと、これらの ことがわかった。諸結果を総合すると、学生の自主的活動を尊重するタイプの、新しい学習方法の吟味・ 評価のためには、学生によるその方法の実践状況の分析が有意義であるだろうこと、また、それは、場 合によっては教員の評価のパラダイムを変える力を持つだろうことなどが予測された。なお、本報告は、 文科省科学研究費補助金「高等教育改革のコミュニケーション分析－現場における文化変容の質的検討 －」（基盤研究（Ｂ）、 課題番号 １８３３０１０５、研究代表者：樫田美雄）ほかによる研究成果 の一部である

The ASTRO-H X-ray Observatory

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

Analysis of the Statistical Time-Access Fairness Index under a Scheduler Exploiting Multiuser Diversity

Recent studies report that in wireless networks, schedulers exploiting multiuser diversity can substantially enhance the maximum throughput of the overall system. In this paper, we focus on a scheduler which maximizes the throughput of the overall system by exploiting multiuser diversity and is combined with adaptive modulation and coding. We numerically study the statistical time-access fairness of the scheduler. The transient statistical fairness properties of schedulers exploiting multiuser diversity have not been sufficiently explored yet, although they are important in practice. We develop two numerical methods to understand the transient statistical fairness properties of the scheduler. Numerical results exhibit that under the scheduler, serious unfairness between users can remain for a relatively long period even if the users have the same average SNR. 1