理化学研究所におけるコンピュータ・ネットワークの構成と利用について紹介した。始めに研究所内で利用している3種類のローカルエリア・ネットワークについて述べ,次に理化学研究所のネットワークが接続されている5種類の広域ネットワークについて概説した。さらに,ネットワーク・アプリケーションの中で最も利用者の多い電子メールについて述べた。

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The reduction of snow removal expenditures is a pressing need for governments in Japan. Reducing snow removal expenditures at the national government level requires the following: 1) analysis of the cost structure, 2) development of a method for comparing costs among regions, and 3) development of cost reduction standards. We studied methods for objectively determining the cost effectiveness of snow removal, toward inter-regional comparison that has been regarded as difficult. To this end, we developed a model uses a linear regression line of "unit cost of snow removal" (UCSR) that is based on the relationship between snow removal costs and cumulative snowfall. This study presents how the model has been developed and discusses its applicability by using actual snow removal records. We also examine applicability of the model when the data from which the model is derived include those for an extremely snowy year and an unusually less snowy year.

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The reduction of snow removal expenditures is a pressing need for governments in Japan. Reducing snow removal expenditures at the national government level requires the following:1) analysis of the cost structure,2) development of a method for comparing costs among regions,and 3) development of cost reduction standards. We studied methods for objectively determining the cost effectiveness of snow removal, toward inter-regional comparison that has been regarded as difficult. To this end, we developed a model uses a linear regression line of"unit cost of snow removal"(UCSR) that is based on the relationship between snow removal costs and cumulative snowfall. This study presents how the model has been developed and discusses its applicability by using actual snow removal records. We also examine applicability of the model when the data from which the model is derived include those for an extremely snowy year and an unusually less snowy year.

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札幌エリアの高速道路の一部区間においては、多様化する通勤形態への対応、および、高速道路の混雑緩和を目的として、ETC 車に限定した高速道路料金割引が導入された。そこで本研究では、ランダム効用理論に基づく Nested Logit モデルを行動理論の基礎とした統合均衡モデルを、札幌近郊の自動車－鉄道ネットワークに対して適用を行い、高速道路への通勤パス導入による利用者の行動の変化が引き起こす、他交通手段への影響を含めた評価を行った。その結果、本研究におけるモデルにおいて高速道路への定額の割引率の導入により、一般道及び鉄道利用者の高速道路への移動が表現することができた。また、一般道における混雑を緩和する際に、必要とされる高速道路の妥当な割引率を求めることが可能となったことから、本モデルの有効性が確かめられた。

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Near-Earth and deep space sources of in situ solar wind magnetic field and plasma data are reviewed, as well as the public accessibility of such data. Then the 1963-1989 multi-source hourly resolution compilation of near-Earth field and plasma parameters (the “?OMNItape”) is discussed. Finally, the variations in selected solar wind parameters over 2.5 solar cycles are presented and discussed. Variabilities among solar cycles are stressed. North-south asymmetries in the apparent rotation rate of the source of the solar wind and divergence of the solar wind flow away from the heliospheric current sheet are highlighted.

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科学技術庁では,本年10月に運用を開始すべくSTAネットワークの準備を進めており,本文では,ネットワーク及び機器の構成,提供されるサービス等の概要について述べた。また,現状の問題点,今後の課題についても簡単にふれた。さらに,我が国でも急速に発展しているインターネットについて,先進国である米国を中心にその概要を述べるとともに,国内の状況,政府の取り組み等にふれた。

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This study proposes a new index for estimating visibility under poor-visibility conditions by using digital images from a road monitoring camera. The method allows representation of the amount of visual information based on human spatial frequency characteristics. A laboratory experiment was performed in 2002 under artificial fog. We examined the weighted intensity of power spectra (WIPS) to determine its applicability as a visibility assessment value. The magnitude of WIPS represented the difference in spatial frequencies within the image based on human contrast sensitivity function. WIPS was calculated from the following image-processing procedure. As an initial step, a box measuring 128 × 128 pixels was cut from the original image. The spatial frequency of the cutout image was calculated using two-dimensional Fourier transform, and the power spectrum of the cutout image was calculated. We totaled the WIPS at five spatial frequencies (cycles per degree, cpd): 1.5 cpd, 3 cpd, 6 cpd, 12 cpd and 18 cpd. WIPS were compared with the subjective visibility assessment values (SVAV) given by test subjects. There was a clear relationship between WIPS and total SVAV: WIPS increased as total SVAV increased. These results suggest that WIPS might be an appropriate index for estimating visibility using digital images.

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Internet and World Wide Web have been introduced in business market these days and number of uses received some benefit from this communication system are increasing every day.
This paper introduces the use of Internet as a business tool in the E & P world from our experiences of using SINet; Schlumberger Information Network System. The paper introduces the use of Internet and WWW as a tool to exchange, transmit, and open information to company employee. In SINet world, Schlumberger employee use E-mail to exchange messages and to distribute information and also uses Web browser to access WWW site available world wide to extract products technical information internally. SINet system also allowed Employ to access external world using E-mail and WWW browser to receive information from public domain database. Computer environment infrastructure based on software and hardware standard. The benefits to the E & P business using this modern computer based technologies were also discussed through Schlumberger's past experiences of building this world biggest private network system.

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