Pin-efficient networks for cubic neighborhoods

We study the task of transforming a hard function f, with which any small circuit disagrees on (1 - /spl delta/)/2 fraction of the input, into a harder function f', with which any small circuit disagrees on (1 - /spl delta//sup k/)/2 fraction of the input, for /spl delta/ /spl isin/ (0,1) and k /spl isin/ /spl Nopf/. We show that this process cannot be carried out in a black-box way by a circuit of depth d and size 2/sup o(k2/d)/ or by a nondeterministic circuit of size o(k/log k) (and arbitrary depth). In particular, for k = 2/sup /spl Omega/(n)/, such hardness amplification cannot be done in ATIME(O(1), 2/sup o(n)/. Therefore, hardness amplification in general requires a high complexity. Furthermore, we show that even without any restriction on the complexity of the amplification procedure, such a black-box hardness amplification must be inherently non-uniform in the following sense. Given as an oracle any algorithm which agrees with f' on (1 - /spl delta//sup k/)/2 fraction of the input, we still need an additional advice of length /spl Omega/(k log(1//spl delta/)) in order to compute f correctly on (1 - /spl delta/)/2 fraction of the input. Therefore, to guarantee the hardness, even against uniform machines, of the function f', one has to start with a function f which is hard against non-uniform circuits. Finally, we derive similar lower bounds for any black-box construction of pseudorandom generators from hard functions.

An exact recursive formula is derived to describe the structure of an ideal first-order /spl Sigma/-/spl Delta/ output sequence as a function of its input. Specifically, it is shown that every /spl Sigma/-/spl Delta/ sequence generated by the constant input x/spl isin/[0, 1] can be decomposed into a shorter E-A subsequence whose input x'/spl isin/[0, 1) may be used to recover that of the original /spl Sigma/-/spl Delta/ sequence. This formula is applied to develop an O(N log N) algorithm for decoding an N-length sequence. Without knowledge of the modulator's initial state, it exhibits an average improvement, over all initial states, of 4.2 dB in output signal-to-noise ratio (SNR) compared with a near-optimal linear finite impulse response (FIR) filter. The regularity of the ideal first-order /spl Sigma/-/spl Delta/ structure with constant inputs permits the algorithm to be extended to bandlimited and noise-corrupted data. A simple error correction procedure is demonstrated, and it is shown that the recursive algorithm can outperform FIR filters on sequences of length N<64 having input SNRs as low as 30 dB.

Evidence for Amazonian mid-latitude glaciation on Mars from impact crater asymmetry

The proliferation of pervasive devices has stimulated the development of applications that support ubiquitous access via multiple modalities. Since the processing capabilities of pervasive devices differ vastly, device-specific application adaptation becomes essential. We address the problem of speech application adaptation by dialog call-flow reorganisation for pervasive devices with different memory constraints. Given an atomic dialog call-flow A and device memory size m, we present optimal deterministic algorithms, RESEQUENCE and BALANCE-TREE, which minimise the number of questions in the reorganised output call-flow A/sub m/. Algorithms MASQ and MATREE produce C/sub m/, minimally distant from input call-flow A/sub m/ while accommodating the memory constraint m. These two minimisation criteria are capable of capturing various usability requirements important in dialog call-flow design. The following observation forms the cornerstone of all the algorithms in this paper: Two grammars g/sub 1/ and g/sub 2/ comprising of |g/sub 1/| and |g/sub 2/| elements respectively can be merged into a single grammar g = g/sub 1/ /spl times/ g/sub 2/ having |g/sub 1/|/spl middot/|g/sub 2/| elements for the sequential case, and g = g/sub 1/ + g/sub 2/ having |g/sub 1/|+|g/sub 2/| elements for the tree case. Device-speciific considerations lead us to introduce the concept of an <m,q>-characterisation of a call-flow, defined as the set of pairs {(m/sub i/,q/sub i/)| /spl isin/ N}, where q/sub i/ is the minimum number of questions required for memory size m/sub i/. Each call-flow has a unique, device-independent signature in its <m,q>-characterisation - a measure of its adaptability. We present SAMVAAD, a system that implements these algorithms on call-flows authored in VXML containing SRGS grammars. The system was tested on an IBM voice browser using a sample airline reservation system call-flow reorganised for memories ranging from 64 MB to 210 KB. We ran an experiment with 14 users to obtain feedback on the usability of the adapted call-flows.

Energy utilization in a wireless sensor network (WSN) is a major concern. In WSN we cannot use rechargeable batteries, because sensor nodes are mostly deployed in areas which are not easily accessible. In this paper, we consider a one dimensional (1-D) network and look at reducing energy during routing of packets. To increase the network lifetime of a WSN, routing protocol should not unnecessarily use all the nodes in the network, instead use minimum number of nodes. So relay node selection plays an important role in energy reduction. In this paper, we use two major algorithms: energy saving via opportunistic routing algorithm (ENS_OR) and geographic random forwarding algorithm (GeRaF) for reducing energy consumption and along with these, we implement sleep mode. We show that use of sleep mode improves network lifetime by reducing energy consumption.

Aim: To determine the spectrum of different complications during tibial lengthening procedure using NA external fixator in our patients at GMC, Gujranwala, and KEMU, Lahore, Pakistan. In addition, this study will also find significant factors associated with occurence of complications in NA fixator-assisted lengthening surgery. Methods: This was a cross-sectional study. The patients who underwent tibial lengthening procedure using NA external fixator were categorized into two categories: fixator complications group and no complications group. Statistical analysis was done using SPSS version 25. Independent sample T test and Chi-square test for independence were used for quantitative and qualitative variables respectively to determine their significant association with the occurrence of complications during tibial lengthening procedure. The p-values were taken statistically significant if &lt; 0.05. Results: Out of a total of 100 patients, 26% suffered loosening of pin, 2% breaking of pin, 2% loosening of pin, 2% loosening of clamp, 2% breaking of clamp, while 66% had no complications. 52% got skin reaction to pins. The occurrence of complications of NA external fixator was significantly lower at younger age (p=0.022). It has positive association with the number of pins inserted during procedure (p=0.037) and negative association with the duration of hospitalization (p=0.003). The complications of NA external fixator occurred more after left leg surgery as compared to after right leg surgery (p=0.012) and were associated with post healing pain (p=0.042). Conclusion: Skin reaction to pins was the commonest complication of NA external fixator in our studied population. The risk of complications of NA fixator had positive correlation with increasing age and number of pins inserted during tibial lengthening procedure. The duration of hospitalization was less while post-healing pain was more among patients in which complications of NA fixator occurred. Complications occurred relatively more after left leg surgery in comparison to right leg surgery. Minimum number of pins should be inserted during lengthening procedure especially in aged people to reduce fixator related complications and post-healing discomfort Keywords: Tibial lengthening surgery, NA external fixator, Complications of fixator, SPSS

For an m × n matrix A over a field F we consider the following quantities: μ(A), the maximum multiplicity of a field element as a component of a nonzero vector in the range of A, and δ(A), the minimum number of distinct entries in a nonzero vector in the range of A. In terms of ramk(A), we describe the set of possible values of μand δ and discuss the possible relations between them. We also develop a general affine geometric structure in which the sets of values of μ and δ may be characterized linear algebraically.

A novel interface architecture allows slow-speed test equipment to control and access scan registers operating at the full clock rate of the chip or the system. The architecture requires simple on-chip hardware and works with a minimal number of chip pins.

The repertory grid is a psychological data collection technique that is used to elicit qualitative data in the form of attributes as well as quantitative ratings. A common approach for evaluating multiple repertory grid data is sorting the elicited bipolar attributes (so called constructs) into mutually exclusive categories by means of content analysis. An important question when planning this type of study is determining the sample size needed to a) discover all attribute categories relevant to the field and b) yield a predefined minimal number of attributes per category. For most applied researchers who collect multiple repertory grid data, programming a numeric simulation to answer these questions is not feasible. The gridsampler software facilitates determining the required sample size by providing a GUI for conducting the necessary numerical simulations. Researchers can supply a set of parameters suitable for the specific research situation, determine the required sample size, and easily explore the effects of changes in the parameter set.

Currently available seed reconstruction algorithms are based on the assumption that accurate information about the imaging geometry is known. The assumption is valid for isocentric x-ray units such as radiotherapy simulators. However, the large majority of the clinics performing prostate brachytherapy today use C-arms for which imaging parameters such as source to axis distance, image acquisition angles, central axis of the image are not accurately known. We propose a seed reconstruction algorithm that requires no such knowledge of geometry. The new algorithm makes use of perspective projection matrix, which can be easily derived from a set of known reference points. The perspective matrix calculates the transformation of a point in 3D space to the imaging coordinate system. An accurate representation of the imaging geometry can be derived from the generalized projection matrix (GPM) with eleven degrees of freedom. In this paper we show how GPM can be derived given a theoretical minimum number of reference points. We propose an algorithm to compute the line equation that defines the backprojection operation given the GPM. The algorithm can be extended to any ray-tracing based seed reconstruction algorithms. Reconstruction using the GPM does not require calibration of C-arms and the images can be acquired at arbitrary angles. The reconstruction is performed in near real-time. Our simulations show that reconstruction using GPM is robust and accuracy is independent of the source to detector distance and location of the reference points used to generate the GPM. Seed reconstruction from C-arm images acquired at unknown geometry provides a useful tool for intra-operative dosimetry in prostate brachytherapy.

An effectiveness-based adaptive cache replacement policy

In this paper, we present a systematic approach to design hardware circuits for bit-dimension permutations. The proposed approach is based on decomposing any bit-dimension permutation into elementary bit-exchanges. Such decomposition is proven to achieve the theoretical minimum number of delays required for the permutation. This offers optimum solutions for multiple well-known problems in the literature that make use of bit-dimension permutations. This includes the design of permutation circuits for the fast Fourier transform, bit reversal, matrix transposition, stride permutations, and Viterbi decoders.

As intended by its name, Physically Unclonable Functions PUFs are considered as an ultimate solution to deal with insecure storage, hardware counterfeiting, and many other security problems. However, many different successful attacks have already revealed vulnerabilities of certain digital intrinsic PUFs. Although settling-state-based PUFs, such as SRAM PUFs, can be physically cloned by semi-invasive and fully-invasive attacks, successful attacks on timing-based PUFs were so far limited to modeling attacks. Such modeling requires a large subset of challenge-response-pairs CRP to successfully model the targeted PUF. In order to provide a final security answer, this paper proves that all arbiter-based i.e. controlled and XOR-enhanced PUFs can be completely and linearly characterized by means of photonic emission analysis. Our experimental setup is capable of measuring every PUF-internal delay with a resolution of 6 picoseconds. Due to this resolution we indeed require only the theoretical minimum number of linear independent equations i.e. physical measurements to directly solve the underlying inhomogeneous linear system. Moreover, we neither require to know the actual PUF challenges nor the corresponding PUF responses for our physical delay extraction. On top of that devastating result, we are also able to further simplify our setup for easier physical measurement handling. We present our practical results for a real arbiter PUF implementation on a Complex Programmable Logic Device CPLD from Altera manufactured in a 180 nanometer process.

A novel single-error-correction (SEC) code is proposed in order to test various fault models simultaneously in both data bit and check bit arrays for word-oriented memories (WOMs). Simultaneous testing of data bit and check bit arrays eliminates the test time and hardware overheads required for separate check bit array tests. The testable faults using the proposed SEC code are the most well-known memory fault models such as single-cell faults and interword and intraword coupling faults. The regularity in data backgrounds (DBs) corresponding to these fault models for WOM tests is investigated. Henceforth, the proposed SEC code is constructed to generate the identical DB patterns for data bit and check bit arrays. Simultaneous testing of data bit and check bit arrays using the proposed SEC codes brings a significant decrease of about 9.9%-33.3% in the time required for memory array tests for 8, 16, 32, and 64 data bits per word. In addition, the number of ones in the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> -matrix of the proposed SEC code is brought close to the theoretical minimum number, thereby reducing the complexity of the check bit generator. For various applications, the proposed SEC code can be represented by many forms of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> -matrices.

While deriving rectangular transforms Agarwal and cooley have used polynomial factors with real integer coefficients which resulted in real convolution matrices. In this paper, it is shown that the use of polynomial factors with complex integer coefficients yields new algorithms with complex convolution matrices, which require less number of multiplications than rectangular transforms. The paper outlines the derivation of the new algorithms and presents the convolution matrices for N = 4,5,7,8 and 9. The results show that the new approach yields smaller theoretical minimum number of multiplications for N = 4 and 8, and the corresponding algorithms are optimum. In view of the simplest factors used in deriving the algorithms for N = 5,7 and 9, it is believed that the corresponding algorithms are the best among those which achieve the theoretical minimum number of multiplications. The matrices have been verified to satisfy the necessary and sufficient condition derived by Agarwal and Cooley.