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Reliability Analysis of Mux - Demux Replicated Multistage Interconnection Networks
No full textThe performance of most digital systems today is limited by their communication or interconnection, not by their logic or memory. The pin density and wiring density that govern interconnections between system components are scaling at a slower rate than the components themselves. Also, the frequency of communication between components is lagging far beyond the clock rates of modern processors. These factors combine to make interconnection the key factor in the success of future digital systems.
The basic function of an interconnection network is to transfer information from the input nodes of the network to the output nodes by setting up communication paths for routing through the network, in an efficient manner. Because the cost of a crossbar network is too high to be practical for building large multiprocessor systems, an alternative to the crossbar network is multistage interconnection network (MIN).1,2 Multiple buses may be a choice, although throughput is a bottleneck.
The interconnection network topologies can be broadly classified as static and dynamic. In a static network, point-to-point links interconnect the network nodes in some fixed topology, like mesh or hypercube. These networks are also referred to as direct networks. Such networks have the advantage of being simple to build and expand, requiring a simple routing algorithm. But such a network fails even in the presence of a single fault, without overheads. Many static networks have been proposed; examples include the Omega Network and the Baseline Network. A dynamic network allows the interconnection pattern among the network nodes to be varied dynamically, being accomplished by some form of switching. Examples of dynamic networks include ASEN, ABN, and so forth, and many bus-based networks. The routing path is fixed in a static MIN, while in a dynamic MIN it is adaptable according to faults/traffic present.
To design MINs, small crossbar switches organized in stages are used. A large number of network designs based on Clos3 and Benes4 networks have been proposed and used in the past three decades. Clos Network was first outlined by Charles Clos in 1953. The first stage of the network consists of r switches, each of size n×m; middle stage has m switches of size r×r each; and the last stage is the mirror image of the first. Thus, the network has N=rn input terminals and output terminals.
Most of the MINs proposed in the literature are usually constructed using 2 × 2 crossbar switches and have n= log2N stages, every stage consisting of N/2 switching elements (SEs). Total number of switches in the network is N/2 (log2N) for N×N network, as compared to O(N2) for a crossbar network. Omega Network5 maintains a uniform connection pattern between stages. Every input terminal has a unique path to every output terminal and exhibits the property of self-routing, that is, routing is performed in a distributed manner using destination address as the “routing tag.” If the stages of Omega Network are traversed backward, inverse path from destination to source is accomplished between stages, to get the inverse Omega Network, which is also a useful MIN in parallel processing environment as it sufficiently supports the communication patterns in several parallel algorithms such as Fast Fourier Transforms and matrix operations.
A wide range of proposed topologies may have a uniform or nonuniform connection pattern between stages. If the number of SEs is the same in each stage, then the MIN is specified as regular, otherwise it is irregular. Applications of regular topologies include such usage where latency provided by all paths is the same. Cube Network is an example of a regular MIN wherein which the SEs are interconnected as the corners of an m-dimensional cube.6 Irregular topologies provide paths of varying lengths, thus reducing the average latency considerably. The irregular Double Tree Network, originally proposed by Levitt et al.,7 has found application in the design of MIT data flow processor.8 Many paths of diverse length are available between any input and output.
Other examples of static MINs include the Shuffle-Exchange Network (SEN),9 the Delta Network,10 Generalized Shuffle-Exchange Network (GSN),11 Data Manipulator Network,1 and Indirect Binary n-cube Network.12 Topological equivalence of several of these networks has been established.13 These networks can also be constructed by using larger sized SEs with corresponding reduction in the number of stages and hence in the latency offered by the network. Unique-path M×N SEN,9 where M=m1m2…mm inputs and N=n1n2…nn. outputs, is composed of r identical stages of SEs sized mi×ni, the ith stage (1 < i < r) incorporating M (n1n2…Nn−1)/(m1m2…mi) crossbar switches.
Delta Networks introduced by Patel10 have the property of digit-controlled routing, which means that a path can be set up through the network in a distributed manner by using individual bits of the destination address. The radix may be 2 or higher. This network has m stages of switches sized a×b, having am input terminals and bm output terminals.
A further generalization of Delta Networks called Generalized Shuffle-Exchange Network was introduced by Bhuyan and Agrawal.11 A GSN with N inputs, M outputs, and r switching stages can be constructed if both N and M are expressible as products of r integers. The integer in such a factorization determines the size of SEs in the r stages. A generalization of the perfect shuffle is used as the interconnection pattern between stages. Thus, these networks belong to the class of irregular banyan networks with r levels
EEG Signal Processing for Monitoring Depth of Anesthesia
No full textAmong the various functional organ systems within the human body, the central nervous system (CNS) is affected maximum by anesthetic drug. Since electroencephalography (EEG) is a phenomenon of cerebral cortex, this signal is the best indicator of anesthesia. The raw EEG signal recorded from the patient in the operation theatre has many undesirable constituents or artifacts which don't allow it to be used directly for predicting the depth of anesthesia. These artifacts include scalp muscle interferences, presence of power line frequency carrier, electrocardiographic (ECG) and eye-blinking effects. This paper describes the methods used to remove these artifacts and enumerates various parameters of EEG signal which undergo significant changes with anesthetic dose. Data processing of 'clean' EEG signal may be carried out using statistical methods to extract those EEG parameters which discriminate maximum between awake and anesthetized states of human patients
Development of Four Channel Programmable FES System using Multi-tap Transformers
Get PDFSpinal cord injuries are predominantly prevalent among younger individuals (> 55% in 16-30 age group). Functional electrical stimulation (FES) is electrical stimulation of muscle deprived of nerves control, with a view of providing muscular contraction and providing a functionally useful movement. The paper reports on the development of a FES system using multi-tap transformers, and also usefulness of the system on a complete paraplegic patient with injury level T-4 to T-12
A Depth of Anaesthesia Index from Linear Regression of EEG Parameters. Journal of Clinical Monitoring and Computing
No full textObjective. The field of Anaesthesia has recently witnessed numerous advances both in the drug administration and monitoring of anaesthetic state. This development has further boosted the efforts and interest of researchers in the automation of clinical Anaesthesia. The success in this direction is possible only when assessment of the depth of hypnotic component of anaesthesia is achieved accurately. This paper describes a technique to arrive at a reliable Depth of Hypnosis (DoH) index using electroencephalographic (EEG) parameters. Methods. EEG data from nine patients was recorded and processed to obtain a total of 21 EEG parameters. They were reduced to a set of best five parameters after applying graphical variance analysis which evaluates their power to discriminate between awake and unresponsive states. These five parameters were normalized with respect to awake state and used in a first order equation to give DoH index. Results. The value of computed DoH index varied from 0.37 to 0.58 for different patients during anesthetized state (awake value 1). For a single patient, the maximum variation in the index was observed as ±5% for different epochs at constant dose. Conclusions. A combination of irregularity of EEG waveform in time-domain and band powers in frequency domain best describes the difference between awake and anesthetized states. To characterize these states, a set of optimum EEG parameters exists. These parameters must be normalized to reduce interpatient variability. The calculated graded index may be used to assist the anaesthetist in the operating theatre
Fuzzy Model for Estimating Induction Dose for General Anesthesia
Get PDFAt present, anesthetist estimates initial anesthetic dose required to produce induction in general anesthesia. This paper proposes a fuzzy model for deciding this dose based on patient data (age, gender, height and weight) and computes the dose by defining IF-THEN rules between age and body surface area. Deviation of predicted initial anesthetic dose from the actual dose given by the anesthetist to patients (9) was found to be within ± 7%
Retrieval of infinite-fringe mode information from beam folding interferometer for direct phase visualization
No full textA recently reported one-beam interferometer using beam folding is quite suitable for carrying out studies on phase objects in finite-fringe mode, but in its present form it is difficult to work with this interferometer in infinite-fringe mode for direct and quick phase visualization, which may be required for certain problems of physical interest. The present paper describes a modification to the beam folding interferometer, where interferometric fringes are superimposed onto a grating to get both finite- as well as infinite-fringe mode information of the test object
An efficient algorithm after ungapped analysis in BLAST
No full textBasic Local Alignment Search Tool (BLAST) is a popular tool used for determining the patterns in
genomic sequences. The algorithm of BLAST has gone for various changes from time to time. One
third of the time is taken by BLAST to perform the gapped analysis on the sequences. An efficient
algorithm has been presented that employs a new approach for curtailing the amount of sequences
that proceed for gapped alignment. So this method will work after the ungapped alignment process is
over. This works because of the fact that it is not necessary to perform gapped alignment for all the
sequences that are coming from ungapped analysis. There is a significant increase in speed of the
alignment process without compromising on the sensitivity of the result
Characteristic evolution of indigenously designed and developed tri-axial force balanced accelerometer
Get PDFThis paper describes indigenously designed and developed tri-axial Force Balanced Accelerometer (FBA) using variable capacitance transduction and electromagnetic feedback. Accelerometer is a highly sensitive, low frequency seismic sensor characterized by rugged construction and proven reliability. It has been designed and developed for ±1g full-scale range with 50 Hz natural frequency mainly for seismic, structural, aerospace and some commercial applications. In a single unit, three accelerometers are orthogonally mounted on a plate and housed in a case for recording all the three components of motion. Characteristics evolution of a natural frequency, damping and noise level, have been done, tested and explained. During designing, most of the technical specifications have been considered for low frequency band from DC to 200Hz applications. Accelerometer is suitable for strong motion recording purpose
Review of Quantum Dot Technologies for Cancer Detection and Treatment
No full textSemiconductor quantum dots (QDs) are nanoparticles that have attracted widespread interest in biology and medicine due to their unique optical and electronic properties. These properties, especially their reduced tendency to photobleach and the dependence of their fluorescence wavelength on their size, make them suitable for fluorescent probing applications to detect cancer biomarkers in vitro and in vivo in cells/tissues/whole body. There is considerable interest among researchers due to the recent developments in QD technology. QDs have been encapsulated in amphiphilic polymers and bound to tumor-targeting ligands and drug delivery vesicles for targeting, imaging and treating tumor cells. Present efforts are focussed on exploring the massive multiplexing capabilities of the QDs for the simultaneous detection of multiple cancer biomarkers in blood assays and cancer tissue biopsies. These advances in the QD technology have unravelled a great deal of information about the molecular events in tumor cells and early diagnosis of cancer
Holographic optical elements encoded security holograms with enhanced features
No full textA simple and cost-effective two-step method for forming encoded security holograms with enhanced features is described in this paper. These security holograms contain enhanced encoded/concealed anti-counterfeit security features, which can only be decoded using a key hologram in the final reading process. The encoded key hologram and the security hologram are in the form of special encoded complex holographic optical elements. When the security hologram is illuminated with the decoding beam, specific moiré-like fringe patterns are formed on the security hologram and in addition several spatially separated bright focused spots are also generated from the security hologram. A careful spatial filtering of these bright spots results in specific moiré patterns at different locations in the observation plane and moreover these patterns contain variable interferometric features. Further, these moilé patterns disappear when the security hologram is perfectly repositioned and only the variable interferometric features are formed. Since these security holograms contain variable interferometric features in addition to the specific moiré patterns and bright focused spots, thus making these holograms suitable for both visual and as well as machine inspection