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COMPUTERIZED SYSTEM FOR centralized processing AND DOCUMENTING RESULTS FROM CHECKING MEANS OF MEASUREMENT

MEASUREMENT TECHNIQUES USSR 1987年第6期30卷 501-503页

作者： GELASHVILI, NV NATKOVICH, YS PROKOFEVA, TV TSERELOV, RA

There are fairly many means of measurement (MM) whose checking cannot currently be automated. On the other hand, in manual checking for such MM, the checker often has to carry out complicated and laborious procedures, including processing the results, making records, and documentation, which can occupy up to 40-50% of the total time. Therefore, automating the operations improves labor productivity and checking performance, which represents a current task. One approach is to use computer interaction. As this article discusses, various types of interaction can be used in accordance with the purpose of the system and the documentation required.

关键词： Checking Economic Resources centralized processing Computerized

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EXPERIENCE GAINED IN APPLYING centralized processing OF TEST RESULTS IN AN ELECTROTECHNICAL MEASUREMENTS DEPARTMENT

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MEASUREMENT TECHNIQUES 1974年第11期17卷 1649-1650页

作者： KUTASEVICH, GP POGORELOV, SI

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Capacity per Unit Area of Distributed Antenna Systems with centralized processing

Capacity per Unit Area of Distributed Antenna Systems with C...

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IEEE Global Communications Conference (GLOBECOM)

作者： Cottatellucci, Laura EURECOM Mobile Commun Dept BP193 F-06560 Sophia Antipolis France

ISBN: (纸本)9781479935123

We consider an extended wireless network with transmit and receive nodes distributed according to Bernoulli lattice processes in 1D and 2D spaces. The received signals are jointly processed at a central unit. The channel is characterized by pathloss attenuation depending on distances between transmit and receive antennas. We introduce a new class of Euclidean random matrix (ERM) to characterize the distributed antenna system (DAS). By leveraging on a suitable decomposition of these ERMs, we propose an approximated analysis of their spectra and use it to provide an analytical approximation of the capacity per unit area of the DAS.

关键词： approximation theory matrix algebra radio networks receiving antennas signal processing transmitting antennas wireless channels 1D space 2D space Bernoulli lattice process DAS ERM Euclidean random matrix analytical approximation capacity per unit area centralized processing distributed antenna system pathloss attenuation receive antenna received signal processing transmit antenna wireless channel wireless network Approximation methods Eigenvalues and eigenfunctions Lattices Matrix decomposition Receiving antennas Vectors

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TRADE-OFFS OF SECURE processing IN centralized VERSUS DISTRIBUTED NETWORKS

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COMPUTER NETWORKS AND ISDN SYSTEMS 1978年第1期2卷 35-43页

作者： LIENTZ, BP WEISS, IR NYU GRAD SCH BUSINESS ADMNEW YORKNY 10003

Simulation was performed for specific network configurations to assess the effect of imposing security measures on a portion of the workload. The results provide a methodology for performing trade off analysis. The trade-offs are presented in terms of the measures of response time, workload, and cost. Network types included distributed, semicentralized, and centralized configurations. The analysis was conducted using a simulation model which is briefly summarized. The results of the simulation for the cases considered indicate that economies of scale shift from centralized to semicentralized configurations for a fixed I/O bound workload. This occurs when throughput degrades, due to the imposition of security measures, approximately 15% (10%) when 10% (20%) of the workload requires secure processing. Degradation is also examined when certain centers process only secure workload versus distributing both secure and non-secure jobs across the network.

关键词： Network simulation computer security centralized processing distributed processing network performance

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centralized and Decentralized IDD Schemes for Cell-Free Massive MIMO Systems: AP Selection and LLR Refinement

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IEEE ACCESS 2024年 12卷 62392-62406页

作者： Ssettumba, Tonny Shao, Zhichao Landau, Lukas T. N. Facina, Michelle Soares Pereira da Silva, Paulo Ricardo Branco de Lamare, Rodrigo C. Pontif Catholic Univ Rio De Janeiro PUC Rio Dept Elect Engn DEE BR-22451900 Rio De Janeiro Brazil Univ Elect Sci & Technol China Yangtze Delta Reg Inst Quzhou Quzhou 324003 Peoples R China Fdn Ctr Pesquisa & Desenvolvimento Telecomunicacoe BR-13086902 Campinas Brazil

In this paper, we propose iterative interference cancellation schemes with access points selection (APs-Sel) for cell-free massive multiple-input multiple-output (CF-mMIMO) systems. Closed-form expressions for centralized and decentralized linear minimum mean square error (LMMSE) receive filters with APs-Sel are derived assuming imperfect channel state information (CSI). Based on the derived expressions, insights are drawn and general expressions are devised for several cases, namely: firstly, MMSE-SIC filter for the non-scalable CF-mMIMO that uses all APs. Secondly, an MMSE-SIC filter assuming perfect channel state information. Thirdly, in this case we assume no interference cancellation and the linear MMSE filter is obtained. Additionally, we formulate a new Gaussian approximation of the likelihood function by deriving new closed-form expressions for the second order statistics (mean and variance) of the detected signal parameters in presence of channel estimation errors, APs-Sel matrix and multi-user interference (MUI). Since the MMSE-SIC filter experiences error propagation due to erroneous decisions from the previous stages, we develop a list-based detector based on LMMSE receive filters for CF-mMIMO systems that exploits interference cancellation and the constellation points to mitigate the error propagation that occurs in conventional MMSE-SIC receivers. An iterative detection and decoding (IDD) scheme that employs low-density parity-check codes is then developed. Moreover, log-likelihood ratio (LLR) refinement strategies based on censoring and a linear combination of local LLRs are proposed to improve the network performance. We assess the proposed centralized and decentralized IDD schemes against existing approaches in terms of bit error rate performance, complexity, and signaling under perfect CSI and imperfect CSI and verify the superiority of the distributed IDD architecture with LLR refinements.

关键词： Detectors Filters Channel estimation Symbols Uplink MIMO communication Decentralized applications Cell-free massive MIMO systems centralized processing decentralized processing iterative detection and decoding list-based detectors

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Excess-Risk of Distributed Stochastic Learners

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IEEE TRANSACTIONS ON INFORMATION THEORY 2016年第10期62卷 5753-5785页

作者： Towfic, Zaid J. Chen, Jianshu Sayed, Ali H. Univ Calif Los Angeles Dept Elect Engn Los Angeles CA 90095 USA MIT Lincoln Lab Lexington MA 02421 USA Microsoft Res Redmond WA 98052 USA

This paper studies the learning ability of consensus and diffusion distributed learners from continuous streams of data arising from different but related statistical distributions. Four distinctive features for diffusion learners are revealed in relation to other decentralized schemes even under left-stochastic combination policies. First, closed-form expressions for the evolution of their excess-risk are derived for strongly convex risk functions under a diminishing step-size rule. Second, using these results, it is shown that the diffusion strategy improves the asymptotic convergence rate of the excess-risk relative to non-cooperative schemes. Third, it is shown that when the in-network cooperation rules are designed optimally, the performance of the diffusion implementation can outperform that of naive centralized processing. Finally, the arguments further show that diffusion outperforms consensus strategies asymptotically and that the asymptotic excess-risk expression is invariant to the particular network topology. The framework adopted in this paper studies convergence in the stronger mean-square-error sense, rather than in distribution, and develops tools that enable a close examination of the differences between distributed strategies in terms of asymptotic behavior, as well as in terms of convergence rates.

关键词： Distributed stochastic optimization diffusion strategies consensus strategies centralized processing excess-risk asymptotic behavior convergence rate combination policy

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EFFICIENT MANAGEMENT OF MATERIALIZED GENERALIZED TRANSITIVE CLOSURE IN centralized AND PARALLEL ENVIRONMENTS

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 1992年第4期4卷 371-381页

作者： GUH, KC YU, C UNIV ILLINOIS DEPT ELECT ENGN & COMP SCICHICAGOIL 60680

A data structure is used to store materialized generalized transitive closure such that the evaluation of generalized transitive closure queries, deletions, and insertions of tuples can be performed efficiently in centralized and parallel environments. For transitive closure of a binary relation, in a single processor environment, it takes on the average O(m") to retrieve the ancestors/descendants of a given node, where m" is the number of ancestors/descendants of the given node, and it takes on the average O(m x m') to perform an insertion or a deletion of a tuple (a, b), where m is the number of ancestors of a plus 1 and m' is the number of descendants of b plus 1. The number of directed paths between two nodes can be determined in O(1) time. In multiprocessor/distributed environments, the time for retrieving the ancestors/descendants of a given node is O(m") plus two rounds of communications between the query processor and the other processors, and the times for insertion and deletion are O(m x d) plus two rounds of communications, where d is the smaller of m' or n/s, where n is the number of distinct attribute values, and s is the number of processors. The technique is generalized to mixed left and right linear recursive queries. The same performance results in terms of retrieval, deletions, and insertions in both centralized and parallel environments are obtained.

关键词： centralized processing DEDUCTIVE DATABASE SYSTEMS DISTRIBUTED AND PARALLEL processing FILE STRUCTURES MATERIALIZED TRANSITIVE CLOSURE MATERIALIZED MULTIPLE LINEAR RECURSIONS

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Potential advantages in heat and power production when biogas is collected from several digesters using dedicated pipelines - A case study in the "Province of West-Flanders" (Belgium)

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RENEWABLE ENERGY 2020年第0期149卷 549-564页

作者： Hengeveld, E. J. Bekkering, J. Van Dael, M. van Gemert, W. J. T. Broekhuis, A. A. Univ Groningen Dept Chem Engn Prod Technol Nijenborgh 4 NL-9747 AG Groningen Netherlands Hanze Res Ctr Energy Zernikepl 11 NL-7947 AS Groningen Netherlands Hasselt Univ Ctr Environm Sci Martelarenlaan 42 B-3500 Hasselt Belgium VITO Boeretang 200 B-2400 Mol Belgium

In the case study "West-Flanders" costs of electricity and heat production are estimated if a dedicated biogas grid using pipelines would be implemented to centralize energy production in a region. Heat may not be used effectively at digester sites, e.g. because of a change in treatment of digestate. A large scale centralized combined heat and power (CHP) engine can produce additional electrical power at a hub, i.e. central collection point, and has lower specific costs compared to decentralized CHPs at digester sites. A biogas transport model is used to calculate transport costs in a grid. These costs, partly balanced by a scale advantage in CHP costs, are attributed to the additional electrical energy (80%) and heat (20%) produced. If the hub is at a digester site, costs of additional electricity can be as low as 4.0 (sic)ct kWh(e)(-1) and are in many cases below 12 (sic)ct kWh(e)(-1), i.e. in the same order of magnitude or lower than costs of electricity from biogas produced using separate CHPs at the different digester sites;costs of heat at the hub show to be lower than 1 (sic)ct kWh(th)(-1) assuming an effective heat use of 50%. In case a hub is situated at a location with high potential heat demand, i.e. a heat sink, transport of biogas from one digester only to a central located hub can provide 3.4 MWth of heat at 1.95 (sic)ct kWh(th)(-1). For such a centrally located hub additional electrical energy costs show to be slightly higher, but with three or more digesters these costs are lower than 20 (sic)ct kWh(e)(-1) and heat costs are around 0.5 (sic)ct kWh(th)(-1). With a centralized hub more renewable energy is produced, i.e. a more efficient use of biomass feedstock. It is concluded that costs for additional electricity and heat can be at a competing level and scale advantages in a CHP can be a driver to collect biogas at a hub using a biogas grid. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Biogas CHP Scale dependency Electrical efficiency Biogas transport Biogas grid centralized processing

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K-User Interference Channels With Backhaul Cooperation: DoF vs. Backhaul Load Trade-Off

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IEEE TRANSACTIONS ON INFORMATION THEORY 2019年第11期65卷 7253-7267页

作者： Kananian, Borna Maddah-Ali, Mohammad Ali Khalaj, Babak Hossein Sharif Univ Technol Elect Engn Dept Tehran *** Iran Inst Res Fundamental Sci Sch Comp Sci Tehran 193955746 Iran

In this paper, we consider K-user interference channels with M antennas per node and with backhaul collaboration in one side (among the transmitters or among the receivers), for M, K epsilon N, and investigate the tradeoff between the rate in the channel versus the communication load in the backhaul. In this investigation, each node is equipped with M antennas and we focus on a first order approximation result, where the rate of the wireless channel is measured by the degrees of freedom (DoF) per user, and the load of the backhaul is measured by the entropy of backhaul messages per user normalized by log of transmit power, at high power regimes. This tradeoff is fully characterized for the case of even values of K and approximately characterized for the case of odd values of K, with vanishing approximation gap as K grows. To achieve DoF of M per user, this result establishes the asymptotic optimality of the most straightforward scheme, called central processing, in which the messages are collected at one of the nodes, centrally processed, and forwarded back to each node. In addition, this result shows that the gain of the schemes, relying on distributed processing, through pairwise communication among the nodes (e.g., cooperative alignment) does not scale with the size of the network. For the converse, we develop a new outer-bound on the tradeoff based on splitting the set of collaborative nodes (transmitters or receivers) into two subsets and assuming full cooperation within each group. We further present a sufficient condition on the wireless channel connectivity, which although more relaxed, guarantees the validity of the above tradeoff. Finally, we show that verifying this condition takes a polynomial time in the network size.

关键词： Interference alignment cooperation alignment degrees of freedom centralized processing

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Radio-Over-Radio: I/Q-Stream Backhauling for Cloud-Based Networks via Millimeter Wave Links

Radio-Over-Radio: I/Q-Stream Backhauling for Cloud-Based Net...

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IEEE Globecom Workshops (GC Wkshps)

作者： Bartelt, Jens Fettweis, Gerhard Tech Univ Dresden Vodafone Chair Mobile Commun Syst Dresden Germany

ISBN: (纸本)9781479928514

Cloud-based centralized processing is one approach to improve mobile networks in terms of capacity, energy consumption, utilization, and cost. However, some joint processing techniques envisioned for such cloud-based networks require the backhauling of received symbols, usually in the form of an I/Q-stream, which requires a drastically higher data rate on the backhaul link than the backhauling of decoded user data. Until recently, the required data rate could only be provided by fiber and not by wireless links, which could be deployed easier and at lower cost. In this paper, we propose the concept of Radio-over-Radio by extending the popular Radio-over-Fiber approach to wireless millimeter wave links. We analyze the characteristics of the new concept and give first results on a joint optimization of the wireless access and backhaul links by means of joint coding under a data rate constraint on the backhaul.

关键词： millimeter wave communications wireless backhaul centralized processing C-RAN

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