Network Performance Characteristics

In this chapter we will consider issues pertaining to parallel performance modeling. We first introduce some network performance characteristics for parallel computers that must be considered when modeling parallel performance. We then present several performance measures for parallel programs, and we discuss how to develop a performance model for a parallel algorithm. Finally, we will discuss how to evaluate performance data and illustrate how reported performance data can be potentially misleading. 

The network performance characteristics for a parallel computer may greatly influence the performance that can be obtained with a parallel application. The latency and bandwidth are among the most important performance characteristics because their values determine the communication overhead for a parallel program. Let us consider how to determine these parameters and how to use them in performance modeling. To model the communication time required for a parallel program, one first needs a model for the time required to send a message between two processes. For most purposes, this time can 

Another network performance characteristic, related to the latency and bandwidth, is the effective bandwidth, which is defined as the message length divided by the total send time 

When evaluating parallel network performance, it is important to ascertain whether reported bandwidth data refer to unidirectional or bidirectional bandwidths. Most communication networks provide bidirectional communication channels, which are able to transmit messages in both directions 

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The difference in speedup curves for these two cases demonstrates that network performance characteristics can have significant impact on the parallel performance of an algorithm. 

In addition to the amount of filler content, the shape, size and size distribution, surface wettability, interface bonding, and compatibility with the matrix resin of the filler can all influence electrical conductivity, mechanical properties, and other performance characteristics of the composite plates. As mentioned previously, to achieve higher electrical conductivity, the conductive graphite or carbon fillers must form an interconnected or percolated network in the dielectrical matrix like that in GrafTech plates. The interface bonding and compatibility between... 

An artificial neural network is a parallel computational model comprised of densely interconnected adaptive processing elements called neurons or units. It is an information-processing system that has certain performance characteristics in common with the biological neural networks (Rumelhart McClelland, 1986). It resembles the... 

The ability to generalize on given data is one of the most important performance characteristics. With appropriate selection of training examples, an optimal network architecture, and appropriate training, the network can map a relationship between input and output that is complete but bounded by the coverage of the training data. 

CIE Publication 53-1982 (Methods of characterizing the performance of radiometers and photometers) and CIE Publication 69-1987 (Methods of characterizing illuminance meters and luminance meters Performance, characteristics and specifications) provide detailed information on this error source and much more. CIE Division 2 TC 2-40 is currently working on an updated revision of these publications. Presently no radiometric applications have reached this level of standardization. However, both the European Thematic Network for UV Measurements (6) and the CIE TC 2-47 (Characterization and calibration methods of UV radiometers), established around 1998, (To prepare a CIE recommendation on methods of... 

While these optimization-based approaches have yielded very useful results for reactor networks, they have a number of limitations. First, proper problem definition for reactor networks is difficult, given the uncertainties in the process and the need to consider the interaction of other process subsystems. Second, all of the above-mentioned studies formulated nonconvex optimization problems for the optimal network structure and relied on local optimization tools to solve them. As a result, only locally optimal solutions could be guaranteed. Given the likelihood of extreme nonlinear behavior, such as bifurcations and multiple steady states, even locally optimal solutions can be quite poor. In addition, superstructure approaches are usually plagued by the question of completeness of the network, as well as the possibility that a better network may have been overlooked by a limited superstructure. This problem is exacerbated by reaction systems with many networks that have identical performance characteristics. (For instance, a single PFR can be approximated by a large train of CSTRs.) In most cases, the simpler network is clearly more desirable. 

Several performance characteristics of rubber such as abrasion resistance, pendulum rebound, Mooney viscosity, modulus, Taber die swell, and rheological properties can be modeled by Eq 7.34. " A complex mathematical model, called links-nodes-blobs was also developed and experimentally tested to express the properties of a filled rubber network system. Blobs are the filler aggregates, nodes are crosslinks and links are interconnecting chains. The model not only allows for... 

Cadotte discovered that aromatic diamines, interfacially reacted with triacyl halides, gave membranes with dramatically different reverse osmosis performance characteristics than membranes based on aliphatic diamines. 56 Before that time, the area of aromatic amines in interfacial membrane formation had been neglected because of two factors (a) the emphasis on chlorine-resistant compositions, which favored use of secondary aliphatic amines such as piperazine, and (b) poor results that had been observed in early work on interfacial aromatic polyamides. The extensive patent network in aromatic polyamide (aramid) technology may also have been a limiting factor. 

The most common technique for improving the properties of a polymerized monomer is to allow it to copolymerize with another monomer. We distinguish between random, graft, block, and alternating copolymers as well as network structures in Figure 1. These copolymers differ in their performance characteristics. The effect of their structure on properties is discussed by S. Russo and B. M. Gallo using copolymers of styrene and methyl methacrylate as examples. 

Well-known network topologies and their performance characteristics. The network degree is the number of links supported by each simple switch, and p is the number of processors Whop is the maximum number of switches through which data must pass, and Be and nsw represent the bisection width and the number of simple switching elements, respectively... 

It has been shown in earlier chapters that in most cases vegetable oil-based polymers exhibit inferior properties compared to analogous petroleum-based polymers. Even though the performance characteristics can be improved by blending and interpenetrating network formation with other polymers and by the formation of conventional composites with natural and/or synthetic fibres, the improvements are not sufficient to meet the requirements of many advanced applications. In addition, the base polymers lost their characteristics of light weight, and transparency (in case of... 

M. L. Meistrell and K. A. Spackman, Proceedings of the 13 th Annual Symposium on Computer Applications in Medical Care, Washington, DC, 1989, pp. 295-301. Evaluation of Neural Network Performance by Receiver Operating Characteristic Analysis Examples from the Biotechnology Domain. 

Simulation carried out showed that performance accuracy is 92% [10]. Neural network exhibits unique characteristics. It is independent processing system, which means degradation of major network performance does not affect the other network s functions. Eurthermore, latest matlab version also provides multifunction of neural networks which facilitate faster in computerized diagnosis. 

Performance Characteristics of Manufacturer Storage with Direct Shipping Network... 

The performance characteristics of manufacturer or distributor storage with consumer pickup sites are summarized in Table 4-5. The main advantages of a network with consumer pickup sites are that it can lower the dehvery cost and expand the set of products sold and customers served online. The major hurdle is the increased handling cost and complexity at the pickup site. Such a network is likely to be most effective if existing retail locations are used as pickup sites, because this type of network improves the economies from existing infrastructure. In particular, such a network can be effective for firms like Seven-Eleven Japan, Walmart, and W.W. Grainger, which have both a network of stores and an online business. Unfortunately, such... 

Performance Characteristics of Network with Consumer Pickup Sites... 

The performance characteristics of a network with customer pickup sites and local retail storage are summarized in Table 4-6. The main advantage of a network with retail storage is that... 

The major objective of the tyre industry is to improve productivity and to extend tyre life. Tyre durability requires heat resistance, antiflex properties, antioxidation and antiozonation. A proper balance of network is important for flex and heat ageing properties. The use of binary system of accelerators such as sulphenamide and commonly used thiuram such as MTD improves cure efficiency but suffers from the adverse effect of scorch and flex properties. The possibility of an N-nitrosamine safe thiuram such as tetrabenzyl thiuram disulphide (TBzTD) is explored to obtain improvement in cure efficiency and a balanced network. The effect of lower amount of TBzTD is studied in sulphenamide cure to obtain better balance of performance characteristics. A crosslink study is done to correlate the properties to the fine structure of the network. 

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