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Tangential motion on a finger pad is a promising method of transmitting directional tactile information to human users. This study examined the identification and discrimination of tangential force motion on an index finger pad. An experimental device was built to automatically and randomly move a small probe in eight radial directions (45° apart) and two distances (0.5 and 1.5 mm). Index fingers of 62 subjects were tested. The results showed that moving the probe at 1.5 mm was detected with more accuracy than the 0.5 mm one. And, the absolute direction was not a statistically significant variable affecting accuracy for 1.5 mm distance, but was a significant effect for 0.5 mm distance. Implications of these results are discussed and future developments are offered within the context of a proposed Braille design with tangential actuators.
This pearl is devoted to a problem posed by Don Knuth about how to justify a certain array-based algorithm for changing the way an undirected graph is represented. In order to set the scene, we delay describing the precise problem until Section 4. Knuth (2011) recorded three different solutions, though no proofs of correctness were provided, nor even much explanation of why they worked. Recently, he asked various computer scientists interested in formal program development whether any of the proposed solutions “could have been discovered in a disciplined manner.” In what follows we respond by developing a purely functional solution. The solution makes heavy use of the operations in the Haskell library Data.Array, and the whole exercise turns out to be a fascinating study of the arithmetic of graphs and arrays. One of the conditions of the problem is that the final algorithm has to be in situ, but we will get to that in due course.
Centered on three themes, this book explores the latest research in plasticity in sensory systems, focusing on visual and auditory systems. It covers a breadth of recent scientific study within the field including research on healthy systems and diseased models of sensory processing. Topics include visual and visuomotor learning, models of how the brain codes visual information, sensory adaptations in vision and hearing as a result of partial or complete visual loss in childhood, plasticity in the adult visual system, and plasticity across the senses, as well as new techniques in vision recovery, rehabilitation, and sensory substitution of other senses when one sense is lost. This unique edited volume, the fruit of an International Conference on Plastic Vision held at York University, Toronto, will provide students and scientists with an overview of the ongoing research related to sensory plasticity and perspectives on the direction of future work in the field.
A graph is called universal for a given graph class (or, equivalently, -universal) if it contains a copy of every graph in as a subgraph. The construction of sparse universal graphs for various classes has received a considerable amount of attention. There is particular interest in tight -universal graphs, that is, graphs whose number of vertices is equal to the largest number of vertices in a graph from . Arguably, the most studied case is that when is some class of trees. In this work, we are interested in (n,Δ), the class of all n-vertex trees with maximum degree at most Δ. We show that every n-vertex graph satisfying certain natural expansion properties is (n,Δ)-universal. Our methods also apply to the case when Δ is some function of n. Since random graphs are known to be good expanders, our result implies, in particular, that there exists a positive constant c such that the random graph G(n,cn−1/3log2n) is asymptotically almost surely (a.a.s.) universal for (n,O(1)). Moreover, a corresponding result holds for the random regular graph of degree cn2/3log2n. Another interesting consequence is the existence of locally sparse n-vertex (n,Δ)-universal graphs. For example, we show that one can (randomly) construct n-vertex (n,O(1))-universal graphs with clique number at most five. This complements the construction of Bhatt, Chung, Leighton and Rosenberg (1989), whose (n,Δ)-universal graphs with merely O(n) edges contain large cliques of size Ω(Δ). Finally, we show that random graphs are robustly (n,Δ)-universal in the context of the Maker–Breaker tree-universality game.
Content-aware image resizing (CAIR) is desired because it preserves prominent regions in a resized image. However, CAIR requires high computational complexity to perform in mobile devices, though it is desired for these displays. Moreover, transmitting the side information for CAIR from the encoder is a problem since it usually requires high bitrates compared with those for image data. In this paper, we present a rate-dependent CAIR method that produce various retargeting results based on the bitrates for side information. Furthermore, we apply the proposed technique to wavelet-based image coding. Our proposed content-aware image coding method provides good performances for both CAIR and image coding.
A standard bridge between automata theory and logic is provided by the notion ofcharacteristic formula. This paper investigates this problem for the class ofevent-recording automata (ERA), a subclass of timed automata in which clocks areassociated with actions and that enjoys very good closure properties. We first study theproblem of expressing characteristic formulae for ERA in Event-Recording Logic (ERL ), alogic introduced by Sorea to express event-based timed specifications. We prove that theconstruction proposed by Sorea for ERA without invariants is incorrect. More generally, weprove that timed bisimilarity cannot in general be expressed in ERL for the class of ERA ,and study under which conditions on ERA it can be. Then, we introduce the logicWTμ , a new logic for event-based timed specificationscloser to the timed logic ℒν that was introduced byLaroussinie, Larsen and Weise. We prove that it is strictly more expressive than ERL , andthat its model-checking problem against ERA is EXPTIME -complete. Finally, we providecharacteristic formulae constructions in WTμ forcharacterizing the general class of ERA up to timed (bi)similarity and study thecomplexity issues.
A frame quality control mechanism for H.264/AVC is proposed in this research. The research objective is to ensure that a suitable quantization parameter (QP) can be assigned to each frame so that the target quality of each frame will be achieved. One of the potential application is consistently maintaining frame quality during the encoding process to facilitate video archiving and/or video surveillance. A single-parameter distortion to quantization (D–Q) model is derived by training a large number of frame blocks. The model parameter can be determined from the frame content before the exact encoding process. Given the target quality for a video frame, we can then select an appropriate QP according to the proposed D–Q model. Model refinement and QP adjustment of subsequent frames can be applied by examining the coding results of previous data. Such quality measurements as peak signal to noise ratio (PSNR) and structural similarity (SSIM) can be employed. The experimental results verify the feasibility of the proposed constant quality video coding framework.
We consider μ-calculus formulas in a normal form: after a prefix offixed-point quantifiers follows a quantifier-free expression. We are interested in theproblem of evaluating (model checking) such formulas in a powerset lattice. We assume thatthe quantifier-free part of the expression can be any monotone function given by ablack-box – we may only ask for its value for given arguments. As a first result we provethat when the lattice is fixed, the problem becomes polynomial (the assumption about thequantifier-free part strengthens this result). As a second result we show that anyalgorithm solving the problem has to ask at least about n2(namely Ω(n2/log n)) queries to the function, even when the expressionconsists of one μ and one ν (the assumption about thequantifier-free part weakens this result).
We describe a sequent calculus μLJ with primitives for inductive andcoinductive datatypes and equip it with reduction rules allowing a sound translation ofGödel’s system T. We introduce the notion of a μ-closedcategory, relying on a uniform interpretation of open μLJformulas as strong functors. We show that any μ-closed category is asound model for μLJ. We then turn to the construction of a concreteμ-closed category based on Hyland-Ong game semantics. The model relieson three main ingredients: the construction of a general class of strong functors calledopen functors acting on the category of games and strategies, thesolution of recursive arena equations by exploiting cycles in arenas, andthe adaptation of the winning conditions of parity games to build initial algebras andterminal coalgebras for many open functors. We also prove a weak completeness result forthis model, yielding a normalisation proof for μLJ.
Research on visual quality assessment has been active during the last decade. In this work, we provide an in-depth review of recent developments in the field. As compared with existing survey papers, our current work has several unique contributions. First, besides image quality databases and metrics, we put equal emphasis on video quality databases and metrics as this is a less investigated area. Second, we discuss the application of visual quality evaluation to perceptual coding as an example for applications. Third, we benchmark the performance of state-of-the-art visual quality metrics with experiments. Finally, future trends in visual quality assessment are discussed.
In this paper, we propose a reversible color transform (RCT) for color images acquired through a Bayer pattern color filter array. One existing RCT with fixed coefficients is simple to implement. However, it is not adaptive to each of input images. Another existing RCT based on eigenvector of covariance matrix of color components, which is equivalent to Karhunen–Loève transform (KLT), is adaptive. However, it requires heavy computational load. We remove a redundant part of this existing method, utilizing fixed statistical relation between two green components at different locations. Comparing to the KLT-based existing RCT, it was observed that the proposed RCT keeps adaptability and has better coding performance, even though its computational load is reduced.
A novel technique based on dynamic stochastic resonance (DSR) in discrete cosine transform (DCT) domain has been proposed in this paper for the enhancement of dark as well as low-contrast images. In conventional DSR-based techniques, the performance of a system can be improved by addition of external noise. However, in the proposed DSR-based work, the intrinsic noise of an image has been utilized to create a noise-induced transition of a dark image to a state of good contrast. The proposed technique significantly enhances the image contrast and color information without losing any image or color data by optimization of bistable system parameters. The performance of the proposed methodology has been measured in terms of relative contrast enhancement factor, perceptual quality measure, and color enhancement factor. When compared with the existing enhancement techniques, such as adaptive histogram equalization, gamma correction, single-scale retinex, multi-scale retinex, modified high-pass filtering, multicontrast enhancement with dynamic range compression, color enhancement by scaling, edge-preserving multi-scale decomposition, automatic control of imaging tool, and various spatial/frequency-domain SR-based techniques, the proposed technique gives remarkable performance in terms of contrast and color enhancement while ascertaining good perceptual quality.
We exhibit seven linear codes exceeding the current best known minimum distance $d$ for their dimension $k$ and block length $n$. Each code is defined over ${ \mathbb{F} }_{8} $, and their invariants $[n, k, d] $ are given by $[49, 13, 27] $, $[49, 14, 26] $, $[49, 16, 24] $, $[49, 17, 23] $, $[49, 19, 21] $, $[49, 25, 16] $ and $[49, 26, 15] $. Our method includes an exhaustive search of all monomial evaluation codes generated by points in the $[0, 5] \times [0, 5] $ lattice square.
Within the past decade, analyzing and modeling human behavior by processing large amounts of collected data has become an active research field in the area of human–machine interaction. The research community is striving to find principled ways to explain and represent important behavioral characteristics of humans, with the goal of developing more efficient and more effective cooperative interactions between humans, machines, and environment. This paper provides a summary of the progress we have achieved to date in our study, which has focused specifically on interactions between driver, vehicle, and driving environment. First, we describe the method of data collection used to develop our on-the-road driving data corpus. We then provide an overview of the data-driven, signal processing approaches we used to analyze and model driver behavior for a wide range of practical vehicle applications. Next, we perform experimental validation by observing the actual driving behavior of groups of real drivers. In particular, the vehicle applications of our research include driver identification, behavior prediction related to car following and lane changing, detection of emotional frustration, and improving driving safety through driver coaching. We hope this paper will provide some insight to researchers with an interest in this field, and help identify areas and applications where further research is needed.
We study iteration and recursion operators in the denotational semantics of typedλ-calculi derived from the multiset relational model of linear logic.Although these operators are defined as fixpoints of typed functionals, we prove themfinitary in the sense of Ehrhard’s finiteness spaces.
We prove that there is a constant c such that, for each positive integer k, every (2k + 1) × (2k + 1) array A on the symbols (1,. . .,2k+1) with at most c(2k+1) symbols in every cell, and each symbol repeated at most c(2k+1) times in every row and column is avoidable; that is, there is a (2k+1) × (2k+1) Latin square S on the symbols 1,. . .,2k+1 such that, for each i,j ∈ {1,. . .,2k+1}, the symbol in position (i,j) of S does not appear in the corresponding cell in A. This settles the last open case of a conjecture by Häggkvist. Using this result, we also show that there is a constant ρ, such that, for any positive integer n, if each cell in an n × n array B is assigned a set of m ≤ ρ n symbols, where each set is chosen independently and uniformly at random from {1,. . .,n}, then the probability that B is avoidable tends to 1 as n → ∞.
In the paper we develop an approach to asymptotic normality through factorial cumulants. Factorial cumulants arise in the same manner from factorial moments as do (ordinary) cumulants from (ordinary) moments. Another tool we exploit is a new identity for ‘moments’ of partitions of numbers. The general limiting result is then used to (re-)derive asymptotic normality for several models including classical discrete distributions, occupancy problems in some generalized allocation schemes and two models related to negative multinomial distribution.
There are advantages in the use of quantum computing in the elaboration of attacks on certain pseudorandom generators when compared with analogous attacks using classical computing. This paper presents a polynomial time quantum attack on the Blum–Micali generator, which is considered secure against threats from classical computers. The proposed attack uses a Grover inspired procedure together with the quantum discrete logarithm, and is able to recover previous and future outputs of the generator under attack, thereby completely compromising its unpredictability. The attack can also be adapted to other generators, such as Blum–Micali generators with multiple hard-core predicates and generators from the Blum–Micali construction, and also to scenarios where the requirements on the bits are relaxed. Such attacks represent a threat to the security of the pseudorandom generators adopted in many real-world cryptosystems.