Brun, TA, Hsieh, M-H & Perry, C 2013, 'Compatibility of state assignments and pooling of information', Phys. Rev. A, vol. 92, no. 1, p. 012107.
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We say that two (or more) state assignments for one and the same quantumsystem are compatible if they could represent the assignments of observers withdiffering information about the system. A criterion for compatibility wasproposed in [Phys. Rev. A 65, 032315 (2002)]; however, this leaves unansweredthe question of whether there are degrees of compatibility which could berepresented by some quantitative measure, and whether there is astraightforward procedure whereby the observers can pool their information toarrive at a unique joint state assignment. We argue that such measures are onlysensible given some assumption about what kind of information was used inmaking the state assignments in the first place, and that in general stateassignments do not represent all of the information possessed by the observers.However, we examine one particular measure, and show that it has astraightforward interpretation, assuming that the information was acquired froma particular type of measurement, and that in this case there is a natural rulefor pooling information. We extend this measure to compatibility of states fork observers, and show that the value is the solution to a semidefinite program.Similar compatibility measures can be defined for alternative notions of statecompatibility, including Post-Peierls (PP) and Equal Support (ES)compatibility.
Bu, GP, Son, JB, Lee, JH, Guan, H, Blumenstein, M & Loo, YC 2013, 'Typical deterministic and stochastic bridge deterioration modelling incorporating backward prediction model', Journal of Civil Structural Health Monitoring, vol. 3, no. 2, pp. 141-152.
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© Springer-Verlag Berlin Heidelberg 2013. A backward prediction model (BPM) has been developed to generate the missing bridge condition ratings in past years, thereby ensuring adequate condition data as required in long-term performance modelling. The BPM establishes a correlation between the known condition ratings and the non-bridge factors, including climate condition, traffic volume and population growth. The aim of this study is to confirm the ability of BPM in improving the prediction accuracy using the existing bridge deterioration models. The prediction accuracies of typical deterministic and stochastic bridge deterioration models are compared when different sets of BPM-generated historical condition ratings are used as input. Comparisons indicate that the prediction error decreases as more historical condition ratings are made available. Notwithstanding the above findings, several limitations of the current deterministic and stochastic bridge deterioration models are also worth noting and further research is essential to improve the prediction accuracy of bridge deterioration modelling.
Callow, D, Lee, J, Blumenstein, M, Guan, H & Loo, Y-C 2013, 'Development of hybrid optimisation method for Artificial Intelligence based bridge deterioration model — Feasibility study', Automation in Construction, vol. 31, pp. 83-91.
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Chen, J, Ji, Z, Kribs, D, Lütkenhaus, N & Zeng, B 2013, 'Symmetric Extension of Two-Qubit States', Phys. Rev. A, vol. 90, no. 3, pp. 032318-032318-10.
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Quantum key distribution uses public discussion protocols to establish sharedsecret keys. In the exploration of ultimate limits to such protocols, theproperty of symmetric extendibility of underlying bipartite states $\rho_{AB}$plays an important role. A bipartite state $\rho_{AB}$ is symmetric extendibleif there exits a tripartite state $\rho_{ABB'}$, such that the $AB$ marginalstate is identical to the $AB'$ marginal state, i.e. $\rho_{AB'}=\rho_{AB}$.For a symmetric extendible state $\rho_{AB}$, the first task of the publicdiscussion protocol is to break this symmetric extendibility. Therefore tocharacterize all bi-partite quantum states that possess symmetric extensions isof vital importance. We prove a simple analytical formula that a two-qubitstate $\rho_{AB}$ admits a symmetric extension if and only if$\tr(\rho_B^2)\geq \tr(\rho_{AB}^2)-4\sqrt{\det{\rho_{AB}}}$. Given theintimate relationship between the symmetric extension problem and the quantummarginal problem, our result also provides the first analytical necessary andsufficient condition for the quantum marginal problem with overlappingmarginals.
Chitambar, E & Hsieh, M-H 2013, 'Revisiting the optimal detection of quantum information', Physical Review A, vol. 88, no. 2.
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In 1991, Peres and Wootters wrote a seminal paper on the nonlocal processing of quantum information. We return to their classic problem and solve it in various contexts. Specifically, for discriminating the 'double trine' ensemble with minimum error, we prove that global operations are more powerful than local operations with classical communication (LOCC). Even stronger, there exists a finite gap between the optimal LOCC probability and that obtainable by separable operations (SEP). Additionally we prove that a two-way, adaptive LOCC strategy can always beat a one-way protocol. Our results demonstrate 'nonlocality without entanglement' in two-qubit pure states. © 2013 American Physical Society.
Chitambar, E, Duan, R & Hsieh, M-H 2013, 'When do Local Operations and Classical Communication Suffice for Two-Qubit State Discrimination?', IEEE Trans. Inform. Theory, vol. 60, no. 3, pp. 3-1561.
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In this paper we consider the conditions under which a given ensemble oftwo-qubit states can be optimally distinguished by local operations andclassical communication (LOCC). We begin by completing the \emph{perfect}distinguishability problem of two-qubit ensembles - both for separableoperations and LOCC - by providing necessary and sufficient conditions for theperfect discrimination of one pure and one mixed state. Then for the well-knowntask of minimum error discrimination, it is shown that \textit{almost all}two-qubit ensembles consisting of three pure states cannot be optimallydiscriminated using LOCC. This is surprising considering that \textit{any} twopure states can be distinguished optimally by LOCC. Special attention is givento ensembles that lack entanglement, and we prove an easy sufficient conditionfor when a set of three product states cannot be optimally distinguished byLOCC, thus providing new examples of the phenomenon known as 'non-localitywithout entanglement'. We next consider an example of $N$ parties who eachshare the same state but who are ignorant of its identity. The state is drawnfrom the rotationally invariant 'trine ensemble', and we establish a tightconnection between the $N$-copy ensemble and Shor's 'lifted' single-copyensemble. For any finite $N$, we prove that optimal identification of thestates cannot be achieved by LOCC; however as $N\to\infty$, LOCC can indeeddiscriminate the states optimally. This is the first result of its kind.Finally, we turn to the task of unambiguous discrimination and derive new lowerbounds on the LOCC inconclusive probability for symmetric states. When appliedto the double trine ensemble, this leads to a rather differentdistinguishability character than when the minimum-error probability isconsidered.
Feng, Y, Yu, N & Ying, M 2013, 'Model checking quantum Markov chains', JOURNAL OF COMPUTER AND SYSTEM SCIENCES, vol. 79, no. 7, pp. 1181-1198.
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Although security of quantum cryptography is provable based on principles of quantum mechanics, it can be compromised by flaws in the design of quantum protocols. So, it is indispensable to develop techniques for verifying and debugging quantum cryptographic systems. Model-checking has proved to be effective in the verification of classical cryptographic protocols, but an essential difficulty arises when it is applied to quantum systems: the state space of a quantum system is always a continuum even when its dimension is finite. To overcome this difficulty, we introduce a novel notion of quantum Markov chain, especially suited for modelling quantum cryptographic protocols, in which quantum effects are encoded as super-operators labelling transitions, leaving the location information (nodes) being classical. Then we define a quantum extension of probabilistic computation tree logic (PCTL) and develop a model-checking algorithm for quantum Markov chains. © 2013 Elsevier Inc. All rights reserved.
Ferrie, C 2013, 'High posterior density ellipsoids of quantum states', New J. Phys., vol. 16, p. 023006.
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Regions of quantum states generalize the classical notion of error bars. Highposterior density (HPD) credible regions are the most powerful of regionestimators. However, they are intractably hard to construct in general. Thispaper reports on a numerical approximation to HPD regions for the purpose oftesting a much more computationally and conceptually convenient class ofregions: posterior covariance ellipsoids (PCEs). The PCEs are defined via thecovariance matrix of the posterior probability distribution of states. Here itis shown that PCEs are near optimal for the example of Pauli measurements onmultiple qubits. Moreover, the algorithm is capable of producing accurate PCEregions even when there is uncertainty in the model.
Ferrie, C & Combes, J 2013, 'Weak value amplification is suboptimal for estimation and detection', Phys. Rev. Lett., vol. 112, no. 4, p. 040406.
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We show using statistically rigorous arguments that the technique of weakvalue amplification (WVA) does not perform better than standard statisticaltechniques for the tasks of single parameter estimation and signal detection.Specifically we prove that post-selection, a necessary ingredient for WVA,decreases estimation accuracy and, moreover, arranging for anomalously largeweak values is a suboptimal strategy. In doing so, we explicitly provide theoptimal estimator, which in turn allows us to identify the optimal experimentalarrangement to be the one in which all outcomes have equal weak values (all assmall as possible) and the initial state of the meter is the maximal eigenvalueof the square of the system observable. Finally, we give precise quantitativeconditions for when weak measurement (measurements without post-selection oranomalously large weak values) can mitigate the effect of uncharacterizedtechnical noise in estimation.
Ferrie, C & Granade, CE 2013, 'Likelihood-free methods for quantum parameter estimation', Phys. Rev. Lett., vol. 112, no. 13, pp. 130402-5.
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In this Letter, we strengthen and extend the connection between simulationand estimation to exploit simulation routines that do not exactly compute theprobability of experimental data, known as the likelihood function. Rather, weprovide an explicit algorithm for estimating parameters of physical modelsgiven access to a simulator which is only capable of producing sample outcomes.Since our algorithm does not require that a simulator be able to efficientlycompute exact probabilities, it is able to exponentially outperform standardalgorithms based on exact computation. In this way, our algorithm opens thedoor for the application of new insights and resources to the problem ofcharacterizing large quantum systems, which is exponentially intractable usingstandard simulation resources.
Fowler, AG, Devitt, SJ & Jones, C 2013, 'Surface code implementation of block code state distillation', Scientific Reports, vol. 3, no. 1.
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Frati, F, Gaspers, S, Gudmundsson, J & Mathieson, L 2013, 'Augmenting graphs to minimize the diameter', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), vol. 8283 LNCS, pp. 383-393.
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We study the problem of augmenting a weighted graph by inserting edges ofbounded total cost while minimizing the diameter of the augmented graph. Ourmain result is an FPT 4-approximation algorithm for the problem.
Furrer, F, Berta, M, Tomamichel, M, Scholz, VB & Christandl, M 2013, 'Position-Momentum Uncertainty Relations in the Presence of Quantum Memory', J. Math. Phys., vol. 55, no. 12, p. 122205.
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A prominent formulation of the uncertainty principle identifies thefundamental quantum feature that no particle may be prepared with certainoutcomes for both position and momentum measurements. Often the statisticaluncertainties are thereby measured in terms of entropies providing a clearoperational interpretation in information theory and cryptography. Recently,entropic uncertainty relations have been used to show that the uncertainty canbe reduced in the presence of entanglement and to prove security of quantumcryptographic tasks. However, much of this recent progress has been focused onobservables with only a finite number of outcomes not including Heisenberg'soriginal setting of position and momentum observables. Here we show entropicuncertainty relations for general observables with discrete but infinite orcontinuous spectrum that take into account the power of an entangled observer.As an illustration, we evaluate the uncertainty relations for position andmomentum measurements, which is operationally significant in that it impliessecurity of a quantum key distribution scheme based on homodyne detection ofsqueezed Gaussian states.
Hamed, A & Lee, T 2013, 'Rank and fooling set size'.
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Say that A is a Hadamard factorization of the identity I_n of size n if theentrywise product of A and the transpose of A is I_n. It can be easily seenthat the rank of any Hadamard factorization of the identity must be at leastsqrt{n}. Dietzfelbinger et al. raised the question if this bound can beachieved, and showed a boolean Hadamard factorization of the identity of rankn^{0.792}. More recently, Klauck and Wolf gave a construction of Hadamardfactorizations of the identity of rank n^{0.613}. Over finite fields, Friesenand Theis resolved the question, showing for a prime p and r=p^t+1 a Hadamardfactorization of the identity A of size r(r-1)+1 and rank r over F_p. Here we resolve the question for fields of zero characteristic, up to aconstant factor, giving a construction of Hadamard factorizations of theidentity of rank r and size (r+1)r/2. The matrices in our construction areblockwise Toeplitz, and have entries whose magnitudes are binomialcoefficients.
Konyagin, SV, Luca, F, Mans, B, Mathieson, L, Sha, M & Shparlinski, IE 2013, 'Functional Graphs of Polynomials over Finite Fields', Journal of Combinatorial Theory. Series B, vol. 116, pp. 87-122.
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Given a function $f$ in a finite field ${\mathbb F}_q$ of $q$ elements, wedefine the functional graph of $f$ as a directed graph on $q$ nodes labelled bythe elements of ${\mathbb F}_q$ where there is an edge from $u$ to $v$ if andonly if $f(u) = v$. We obtain some theoretic estimates on the number ofnon-isomorphic graphs generated by all polynomials of a given degree. We thendevelop a simple and practical algorithm to test the isomorphism of quadraticpolynomials that has linear memory and time complexities. Furthermore, weextend this isomorphism testing algorithm to the general case of functionalgraphs, and prove that, while its time complexity increases only slightly, itsmemory complexity remains linear. We exploit this algorithm to provide an upperbound on the number of functional graphs corresponding to polynomials of degree$d$ over ${\mathbb F}_q$. Finally, we present some numerical results andcompare function graphs of quadratic polynomials with those generated by randommaps and pose interesting new problems.
Langford, NK 2013, 'Errors in quantum tomography: diagnosing systematic versus statistical errors', New Journal of Physics, vol. 15, no. 3, pp. 035003-035003.
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Lee, J, Blumenstein, M, Guan, H & Loo, Y 2013, 'Minimising uncertainty in long‐term prediction of bridge element', Engineering, Construction and Architectural Management, vol. 20, no. 2, pp. 127-142.
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PurposeSuccessful bridge management system (BMS) development requires a reliable bridge deterioration model, which is the most crucial component in a BMS. Historical condition ratings obtained from biennial bridge inspections are a major source for predicting future bridge deterioration in BMSs. However, historical condition ratings are very limited in most bridge agencies, thus posing a major barrier for predicting reliable future bridge performance. The purpose of this paper is to present a preliminary study as part of a long‐term research on the development of a reliable bridge deterioration model using advanced Artificial Intelligence (AI) techniques.Design/methodology/approachThis proposed study aims to develop a reliable deterioration model. The development work consists of two major Stages: stage 1 – generating unavailable bridge element condition rating records using the Backward Prediction Model (BPM). This helps to provide sufficient historical deterioration patterns for each element; and stage 2 – predicting long‐term condition ratings based on the outcome of Stage 1 using time delay neural networks (TDNNs).FindingsLong‐term prediction using proposed method can also be expressed in the same form of inspection records – element quantities of each bridge element can be predicted. The proposed AI‐based deterioration model does not ignore critical failure risks in small number of bridge elements in low condition states (CSs). This implies that the risk in long‐term predictions can be reduced.Originality/valueThe proposed methodology aims to utilise limited bridge inspection records over a short period t...
Lee, T & Roland, J 2013, 'A strong direct product theorem for quantum query complexity', computational complexity, vol. 22, no. 2, pp. 429-462.
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Lee, Y-C, Hsieh, M-H, Flammia, ST & Lee, R-K 2013, 'Local PT symmetry violates the no-signaling principle', Phys. Rev. Lett., vol. 112, no. 13, p. 130404.
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Bender et al. have developed PT-symmetric quantum theory as an extension ofquantum theory to non-Hermitian Hamiltonians. We show that when this model hasa local PT symmetry acting on composite systems it violates the non-signalingprinciple of relativity. Since the case of global PT symmetry is known toreduce to standard quantum mechanics, this shows that the PT-symmetric theoryis either a trivial extension or likely false as a fundamental theory.
Lunghi, T, Kaniewski, J, Bussieres, F, Houlmann, R, Tomamichel, M, Kent, A, Gisin, N, Wehner, S & Zbinden, H 2013, 'Experimental bit commitment based on quantum communication and special relativity', Phys. Rev. Lett., vol. 111, no. 18, p. 180504.
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Bit commitment is a fundamental cryptographic primitive in which Bob wishesto commit a secret bit to Alice. Perfectly secure bit commitment has beenproven impossible through asynchronous exchange of classical and quantuminformation. Perfect security is however possible by restraining the exchangeof classical and quantum information to suitably chosen relativisticconstraints. This requires Alice (and Bob) to split into two remote agentsperforming space-like separated classical communication, and in one agentexchanging quantum bits with the other party. The duration of the commitment isgiven by the distance between the two remote agents. The original protocolrequires the quantum communication to happen at a precise location and timewith respect to the classical communication. We show how the protocol can bemodified to relax this constraint such that the quantum part of the protocolcan be performed at any time before the actual commitment, making it much morepractical. Finally, we present an experimental demonstration of this protocolrealized with a commercial quantum key distribution system and withsynchronized classical agents located in Geneva and Singapore, yielding acommitment time of 15 ms. Our work includes a complete security analysis,accounting for experimental imperfections (multi-photon emission, transmissionloss, detector inefficiency and dark counts) and finite statistics.
Mahler, DH, Rozema, LA, Darabi, A, Ferrie, C, Blume-Kohout, R & Steinberg, AM 2013, 'Adaptive Quantum State Tomography Improves Accuracy Quadratically', Physical Review Letters, vol. 111, no. 18.
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Metcalf, BJ, Thomas-Peter, N, Spring, JB, Kundys, D, Broome, MA, Humphreys, PC, Jin, X-M, Barbieri, M, Steven Kolthammer, W, Gates, JC, Smith, BJ, Langford, NK, Smith, PGR & Walmsley, IA 2013, 'Multiphoton quantum interference in a multiport integrated photonic device', Nature Communications, vol. 4, no. 1.
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Müller-Lennert, M, Dupuis, F, Szehr, O, Fehr, S & Tomamichel, M 2013, 'On quantum Renyi entropies: a new generalization and some properties', J. Math. Phys., vol. 54, no. 12, p. 122203.
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The Renyi entropies constitute a family of information measures thatgeneralizes the well-known Shannon entropy, inheriting many of its properties.They appear in the form of unconditional and conditional entropies, relativeentropies or mutual information, and have found many applications ininformation theory and beyond. Various generalizations of Renyi entropies tothe quantum setting have been proposed, most notably Petz's quasi-entropies andRenner's conditional min-, max- and collision entropy. Here, we argue thatprevious quantum extensions are incompatible and thus unsatisfactory. We propose a new quantum generalization of the family of Renyi entropies thatcontains the von Neumann entropy, min-entropy, collision entropy and themax-entropy as special cases, thus encompassing most quantum entropies in usetoday. We show several natural properties for this definition, includingdata-processing inequalities, a duality relation, and an entropic uncertaintyrelation.
Nunn, J, Langford, NK, Kolthammer, WS, Champion, TFM, Sprague, MR, Michelberger, PS, Jin, X-M, England, DG & Walmsley, IA 2013, 'Enhancing Multiphoton Rates with Quantum Memories', Physical Review Letters, vol. 110, no. 13.
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Pal, S, Pal, U & Blumenstein, M 2013, 'Off‐line verification technique for Hindi signatures', IET Biometrics, vol. 2, no. 4, pp. 182-190.
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Handwritten signature is one of the oldest biometric attributes used for authentication of an individual or a document. The purpose of this study is to present an empirical contribution towards the understanding of signature verification using a novel method involving off-line Hindi (Devnagari) signatures. Although research in the field of signature verification involving Western signatures has been well studied, there has been relatively little attention devoted to non-Western signatures such as Chinese, Japanese, Arabic, Persian etc. In this study, the performance of an off-line signature verification system involving Hindi signatures, whose style is distinct from Western scripts, was investigated. The gradient feature, Zernike moment features and SVMs were considered for verification. To the best of the authors' knowledge, Hindi signatures investigated as part of a large dataset have never been used for the task of signature verification, and this research work is only the second important report using Hindi signatures in this area. An encouraging accuracy of 90.69% was obtained using gradient feature. The Hindi signature database employed for experimentation consisted of 2400 (100 × 24) genuine signatures and 3000 (100 × 30) forgeries. The error rates of 11.50% FRR and 7.12% FAR were obtained through experimentation using gradient features. © The Institution of Engineering and Technology 2013.
Ross, P & Blumenstein, M 2013, 'Cloud computing: the nexus of strategy and technology', Journal of Business Strategy, vol. 34, no. 4, pp. 39-47.
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PurposeThe purpose of this paper is to analyse the impact of Cloud technologies on management practices and business strategies. It considers the role of human resource management (HRM) departments in supporting the organisational changes required for the introduction and integration of Cloud business strategies.Design/methodology/approachThe study uses a qualitative exploratory research approach. It utilises the resource view of the firm and transaction costs economics (TCE) to support the analysis. It synthesises the literature with the qualitative interview data.FindingsCloud business models require organisations to focus on the nexus of business strategies and information and communication technology (ICT) capabilities. HRM departments can play a positive role in this process by better integrating ICT sections into business decision‐making processes. Cloud technologies may further change ICT worker functions and roles.Research limitations/implicationsQualitative research approaches may limit the generality of the findings. However they allowed for an in‐depth analysis of complex Cloud related data that quantitative approaches may not have elicited.Practical implicationsThe paper outlines a strategic “holistic” approach for organisations shifting to Cloud‐based business models.Social implications
Spring, JB, Metcalf, BJ, Humphreys, PC, Kolthammer, WS, Jin, X-M, Barbieri, M, Datta, A, Thomas-Peter, N, Langford, NK, Kundys, D, Gates, JC, Smith, BJ, Smith, PGR & Walmsley, IA 2013, 'Boson Sampling on a Photonic Chip', Science, vol. 339, no. 6121, pp. 798-801.
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Computing Power of Quantum Mechanics There is much interest in developing quantum computers in order to perform certain tasks much faster than, or that are intractable for, a classical computer. A general quantum computer, however, requires the fabrication and operation a number of quantum logic devices (see the Perspective by Franson ). Broome et al. (p. 794 , published online 20 December) and Spring et al. (p. 798 , published online 20 December) describe experiments in which single photons and quantum interference were used to perform a calculation (the permanent of a matrix) that is very difficult on a classical computer. Similar to random walks, quantum walks on a graph describe the movement of a walker on a set of predetermined paths; instead of flipping a coin to decide which way to go at each point, a quantum walker can take several paths at once. Childs
Spring, JB, Salter, PS, Metcalf, BJ, Humphreys, PC, Moore, M, Thomas-Peter, N, Barbieri, M, Jin, X-M, Langford, NK, Kolthammer, WS, Booth, MJ & Walmsley, IA 2013, 'On-chip low loss heralded source of pure single photons', Optics Express, vol. 21, no. 11, pp. 13522-13522.
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Tan, VYF & Tomamichel, M 2013, 'The Third-Order Term in the Normal Approximation for the AWGN Channel', IEEE Trans. Inf. Theory, vol. 61, no. 5, pp. 2430-2438.
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This paper shows that, under the average error probability formalism, thethird-order term in the normal approximation for the additive white Gaussiannoise channel with a maximal or equal power constraint is at least $\frac{1}{2}\log n + O(1)$. This matches the upper bound derived byPolyanskiy-Poor-Verd\'{u} (2010).
Tomamichel, M & Tan, VYF 2013, 'Second-Order Asymptotics for the Classical Capacity of Image-Additive Quantum Channels', Communication in Mathematical Physics, vol. 338, no. 1, pp. 103-137.
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We study non-asymptotic fundamental limits for transmitting classicalinformation over memoryless quantum channels, i.e. we investigate the amount ofclassical information that can be transmitted when a quantum channel is used afinite number of times and a fixed, non-vanishing average error is permissible.We consider the classical capacity of quantum channels that are image-additive,including all classical to quantum channels, as well as the product statecapacity of arbitrary quantum channels. In both cases we show that thenon-asymptotic fundamental limit admits a second-order approximation thatillustrates the speed at which the rate of optimal codes converges to theHolevo capacity as the blocklength tends to infinity. The behavior is governedby a new channel parameter, called channel dispersion, for which we provide ageometrical interpretation.
Tomamichel, M & Tan, VYF 2013, 'Second-Order Coding Rates for Channels with State', IEEE Trans. Inf. Theory, vol. 60, no. 8, pp. 4427-4448.
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We study the performance limits of state-dependent discrete memorylesschannels with a discrete state available at both the encoder and the decoder.We establish the epsilon-capacity as well as necessary and sufficientconditions for the strong converse property for such channels when the sequenceof channel states is not necessarily stationary, memoryless or ergodic. We thenseek a finer characterization of these capacities in terms of second-ordercoding rates. The general results are supplemented by several examplesincluding i.i.d. and Markov states and mixed channels.
Tomamichel, M, Berta, M & Hayashi, M 2013, 'Relating different quantum generalizations of the conditional Renyi entropy', J. Math. Phys. 55 (8), 082206 (2014), vol. 55, no. 8.
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Recently a new quantum generalization of the Renyi divergence and thecorresponding conditional Renyi entropies was proposed. Here we report on asurprising relation between conditional Renyi entropies based on this newgeneralization and conditional Renyi entropies based on the quantum relativeRenyi entropy that was used in previous literature. Our result generalizes thewell-known duality relation H(A|B) + H(A|C) = 0 of the conditional von Neumannentropy for tripartite pure states to Renyi entropies of two different kinds. As a direct application, we prove a collection of inequalities that relatedifferent conditional Renyi entropies and derive a new entropic uncertaintyrelation.
Veitch, V, Ferrie, C, Gross, D & Emerson, J 2013, 'Corrigendum: Negative quasi-probability as a resource for quantum computation', New Journal of Physics, vol. 15, no. 3, pp. 039502-039502.
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Wi, HJ, Lee, JH, Blumenstein, M, Guan, H & Loo, YC 2013, 'Development of Methodology for Enhancing Visual Bridge Condition Assessment Using Image Processing Techniques', Applied Mechanics and Materials, vol. 256-259, no. PART 1, pp. 1563-1570.
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Many bridge authorities have implemented Bridge Information Systems (BISs) or Bridge Management Systems (BMSs) to effectively manage their routine inspection information. The success of a BMS is highly dependent on the quality of bridge inspection outcomes and accurate estimation of future bridge condition ratings. To ensure such successful outcomes, a BMS must (1) contain reliable, consistent and accurate condition data from routine bridge inspections; and (2) encompass reliable deterioration modelling that overcomes the shortcomings of a lack of historical bridge inspection records. However published literature demonstrates that several limitations exist particularly in terms of inconsistency of inspection outcomes due to subjective judgment. To minimise such limitations, this paper presents a feasibility study for the enhancement of the current visual bridge inspection method using optical image processing techniques. The development work consists of image processing and knowledge-based approaches. It is anticipated that the proposed method is capable of minimising the shortcomings of subjective judgment on condition rating assessment and providing cost effective solutions to bridge agencies. Ultimately, the proposed bridge inspection methodology can provide consistent and accurate evaluation on the condition states of bridge elements. This in turn will lead to more reliable predictions of long-term bridge performance.
Ying, M, Yu, N, Feng, Y & Duan, R 2013, 'Verification of quantum programs', SCIENCE OF COMPUTER PROGRAMMING, vol. 78, no. 9, pp. 1679-1700.
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This paper develops verification methodology for quantum programs, and the contribution of the paper is two-fold. Sharir, Pnueli and Hart [M. Sharir, A. Pnueli, S. Hart, Verification of probabilistic programs, SIAM Journal of Computing 13 (1984) 292-314] presented a general method for proving properties of probabilistic programs, in which a probabilistic program is modeled by a Markov chain and an assertion on the output distribution is extended to an invariant assertion on all intermediate distributions. Their method is essentially a probabilistic generalization of the classical Floyd inductive assertion method. In this paper, we consider quantum programs modeled by quantum Markov chains which are defined by super-operators. It is shown that the Sharir-Pnueli-Hart method can be elegantly generalized to quantum programs by exploiting the Schrödinger-Heisenberg duality between quantum states and observables. In particular, a completeness theorem for the Sharir-Pnueli-Hart verification method of quantum programs is established.As indicated by the completeness theorem, the Sharir-Pnueli-Hart method is in principle effective for verifying all properties of quantum programs that can be expressed in terms of Hermitian operators (observables). But it is not feasible for many practical applications because of the complicated calculation involved in the verification. For the case of finite-dimensional state spaces, we find a method for verification of quantum programs much simpler than the Sharir-Pnueli-Hart method by employing the matrix representation of super-operators and Jordan decomposition of matrices. In particular, this method enables us to compute easily the average running time and to analyze some interesting long-run behaviors of quantum programs in a finite-dimensional state space. © 2012 Elsevier B.V. All rights reserved.
Yu, N, Duan, R & Ying, M 2013, 'Five two-qubit gates are necessary for implementing the Toffoli gate', PHYSICAL REVIEW A, vol. 88, no. 1.
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In this Rapid Communication, we consider the open problem of the minimum cost of two-qubit gates for simulating the Toffoli gate and show that five two-qubit gates are necessary. Before our work, it was known that five two-qubit gates are sufficient to implement the Toffoli gate, and numerical evidence indicates that five two-qubit gates are also necessary. The idea introduced here can also be used to solve the problem of optimal simulation of Deutsch three-qubit gates. © 2013 American Physical Society.
Alon, N, Lee, T, Shraibman, A & Vempala, S 1970, 'The approximate rank of a matrix and its algorithmic applications', Proceedings of the forty-fifth annual ACM symposium on Theory of Computing, STOC'13: Symposium on Theory of Computing, ACM.
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Beigi, S, Chen, J, Grassl, M, Ji, Z, Wang, Q & Zeng, B 1970, 'Symmetries of Codeword Stabilized Quantum Codes', Leibniz International Proceedings in Informatics, LIPIcs, pp. 192-206.
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Symmetry is at the heart of coding theory. Codes with symmetry, especiallycyclic codes, play an essential role in both theory and practical applicationsof classical error-correcting codes. Here we examine symmetry properties forcodeword stabilized (CWS) quantum codes, which is the most general frameworkfor constructing quantum error-correcting codes known to date. A CWS code Q canbe represented by a self-dual additive code S and a classical code C, i.,e.,Q=(S,C), however this representation is in general not unique. We show that forany CWS code Q with certain permutation symmetry, one can always find aself-dual additive code S with the same permutation symmetry as Q such thatQ=(S,C). As many good CWS codes have been found by starting from a chosen S,this ensures that when trying to find CWS codes with certain permutationsymmetry, the choice of S with the same symmetry will suffice. A key step forthis result is a new canonical representation for CWS codes, which is given interms of a unique decomposition as union stabilizer codes. For CWS codes, sofar mainly the standard form (G,C) has been considered, where G is a graphstate. We analyze the symmetry of the corresponding graph of G, which ingeneral cannot possess the same permutation symmetry as Q. We show that it isindeed the case for the toric code on a square lattice with translationalsymmetry, even if its encoding graph can be chosen to be translationalinvariant.
Chen, J, Cao, J, Abawajy, J, Mauri, JL, Bennamoun, M, Goscinski, A, Blumenstein, M, Wei, D & Yang, LT 1970, 'Message from CIT2013 Chairs', 2013 IEEE 16th International Conference on Computational Science and Engineering, 2013 IEEE 16th International Conference on Computational Science and Engineering (CSE), IEEE, p. 23.
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Das, A, Pal, U, Ballester, MAF & Blumenstein, M 1970, 'A New Method for Sclera Vessel Recognition Using OLBP', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Biometric Recognition, Springer International Publishing, Jinan, China, pp. 370-377.
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This paper proposes a new sclera vessel recognition technique. The vessel patterns of sclera are unique for each individual and this can be utilized to identify a person uniquely. In this research we have used a time adaptive active contour-based region growing technique for sclera segmentation. Prior to that, we have made some tonal and illumination correction to get a clearer sclera area without the distributing vessel structure. This is because the presence of complex vessel structures occasionally affects the region-growing process. The sclera vessels are not prominent in the images, so in order to make them clearly visible, a local image enhancement process using a Haar high pass filter is incorporated. To get the total orientation of the vessels, we have used Orientated Local Binary Pattern (OLBP). The OLBP images of each class are used for template matching for classification by calculating the minimum Hamming Distance. We have used the UBIRIS version 1 dataset for the experimentation of our research. The proposed approach has achieved high recognition accuracy employing the above-mentioned dataset. © Springer International Publishing 2013.
Das, A, Pal, U, Blumenstein, M & Ballester, MAF 1970, 'Sclera Recognition - A Survey', 2013 2nd IAPR Asian Conference on Pattern Recognition, 2013 2nd IAPR Asian Conference on Pattern Recognition (ACPR), IEEE, Naha, Japan, pp. 917-921.
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This paper presents a survey on sclera-based biometric recognition. Among the various biometric methods, sclera is one of the novel and promising biometric techniques. The sclera, a white region of connective tissue and blood vessels, surrounds the iris. A survey of the techniques available in the area of sclera biometrics will be of great assistance to researchers, and hence a comprehensive effort is made in this article to discuss the advancements reported in this regard during the past few decades. As a limited number of publications are found in the literature, an attempt is made in this paper to increase awareness of this area so that the topic gains popularity and interest among researchers. In this survey, a brief introduction is given initially about the sclera biometric, which is subsequently followed by background concepts, various pre-processing techniques, feature extraction and finally classification techniques associated with the sclera biometric. Benchmarking databases are very important for any pattern recognition related research, so the databases related with this work is also discussed. Finally, our observations, future scope and existing difficulties, which are unsolved in sclera biometrics, are discussed. We hope that this survey will serve to focus more researcher attention towards the emerging sclera biometric. © 2013 IEEE.
Das, A, Pal, U, Ferrer Ballester, MA & Blumenstein, M 1970, 'Sclera recognition using dense-SIFT', 2013 13th International Conference on Intellient Systems Design and Applications, 2013 13th International Conference on Intelligent Systems Design and Applications (ISDA), IEEE, Bangi, Malaysia, pp. 74-79.
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© 2013 IEEE. In this paper we propose a biometric sclera recognition and validation system. Here the sclera segmentation is performed bya time-adaptive active contour-based region growing technique. The sclera vessels are not prominent so image enhancement is required and hence a bank of 2D decomposition. A Haar wavelet multi-resolution filter is used to enhance the vessels pattern for better accuracy. For feature extraction, Dense Scale Invariant Feature Transform (D-SIFT) is used. D-SIFT patch descriptors of each training image are used to form bag of features by using k-means clustering and a spatial pyramid model, which is used to produce the training model. Support Vector Machines (SVMs) are used for classification. The UBIRIS version 1 dataset is used here for experimentation. Anencouraging Equal Error Rate (EER) of 0.66% is attained in the experiments presented.
Feng, Y, Yu, N & Ying, M 1970, 'Reachability Analysis of Recursive Quantum Markov Chains', MATHEMATICAL FOUNDATIONS OF COMPUTER SCIENCE 2013, International Symposium on Mathematical Foundations of Computer Science, Springer, IST Austria, pp. 385-396.
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We introduce the notion of recursive quantum Markov chain (RQMC) for analysing recursive quantum programs with procedure calls. RQMCs are natural extension of Etessami and Yannakakis's recursive Markov chains where the probabilities along transitions are replaced by completely positive and trace-nonincreasing super-operators on a state Hilbert space of a quantum system. We study the reachability problem for RQMCs and establish a reduction from it to computing the least solution of a system of polynomial equations in the semiring of super-operators. It is shown that for an important subclass of RQMCs, namely linear RQMCs, the reachability problem can be solved in polynomial time. For general case, technique of Newtonian program analysis recently developed by Esparza, Kiefer and Luttenberger is employed to approximate reachability super-operators. A polynomial time algorithm that computes the support subspaces of the reachability super-operators in general case is also proposed. © 2013 Springer-Verlag.
Gupta, A, Kayal, N & Qiao, Y 1970, 'Random Arithmetic Formulas Can Be Reconstructed Efficiently', 2013 IEEE Conference on Computational Complexity, 2013 IEEE Conference on Computational Complexity (CCC), IEEE, Palo Alto, CA, pp. 1-9.
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Kulkarni, R, Qiao, Y & Sun, X 1970, 'Any Monotone Property of 3-Uniform Hypergraphs Is Weakly Evasive', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Theory and Applications of Models of Computation, Springer Berlin Heidelberg, Hong Kong, pp. 224-235.
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For a Boolean function f, let D(f) denote its deterministic decision tree complexity, i.e., minimum number of (adaptive) queries required in worst case in order to determine f. In a classic paper, Rivest and Vuillemin [18] show that any non-constant monotone property P: {0,1} (2n) → {0,1} of n-vertex graphs has D(P) = Ω (n). We extend their result to 3-uniform hypergraphs. In particular, we show that any non-constant monotone property P: {0,1} (3n) → {0,1} of n-vertex 3-uniform hypergraphs has D(P) = Ω (n). Our proof combines the combinatorial approach of Rivest and Vuillemin with the topological approach of Kahn, Saks, and Sturtevant. Interestingly, our proof makes use of Vinogradov's Theorem (weak Gold-bach Conjecture), inspired by its recent use by Babai et. al. [1] in the context of the topological approach. Our work leaves the generalization to k-uniform hypergraphs as an intriguing open question. © Springer-Verlag Berlin Heidelberg 2013.
Kunwar, R, Pal, U & Blumenstein, M 1970, 'Semi-supervised Online Learning of Handwritten Characters Using a Bayesian Classifier', 2013 2nd IAPR Asian Conference on Pattern Recognition, 2013 2nd IAPR Asian Conference on Pattern Recognition (ACPR), IEEE, Naha, Japan, pp. 717-721.
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This paper addresses the problem of creating a handwritten character recognizer, which makes use of both labelled and unlabelled data to learn continuously over time to make the recognisor adaptable. The proposed method makes learning possible from a continuous inflow of a potentially unlimited amount of data without the requirement for storage. It highlights the use of unlabelled data for better parameter estimation, especially when labelled data is scarce and expensive unlike unlabelled data. We introduce an algorithm for learning from labelled and unlabelled samples based on the combination of novel online ensemble of the Randomized Naive Bayes classifiers and a novel incremental variant of the Expectation Maximization (EM) algorithm. We make use of a weighting factor to modulate the contribution of unlabelled data. An empirical evaluation of the proposed method on Tamil handwritten base character recognition proves efficacy of the proposed method to carry out incremental semi-supervised learning and producing accuracy comparable to state-of-the-art batch learning method. Online handwritten Tamil characters from the IWFHR 2006 competition dataset was used for evaluating the proposed method. © 2013 IEEE.
Lee, T & Shraibman, A 1970, 'Matrix completion from any given set of observations', Advances in Neural Information Processing Systems.
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In the matrix completion problem the aim is to recover an unknown real matrix from a subset of its entries. This problem comes up in many application areas, and has received a great deal of attention in the context of the netflix prize. A central approach to this problem is to output a matrix of lowest possible complexity (e.g. rank or trace norm) that agrees with the partially specified matrix. The performance of this approach under the assumption that the revealed entries are sampled randomly has received considerable attention (e.g. [1, 2, 3, 4, 5, 6, 7, 8]). In practice, often the set of revealed entries is not chosen at random and these results do not apply. We are therefore left with no guarantees on the performance of the algorithm we are using. We present a means to obtain performance guarantees with respect to any set of initial observations. The first step remains the same: find a matrix of lowest possible complexity that agrees with the partially specified matrix. We give a new way to interpret the output of this algorithm by next finding a probability distribution over the non-revealed entries with respect to which a bound on the generalization error can be proven. The more complex the set of revealed entries according to a certain measure, the better the bound on the generalization error.
Malik, MI, Liwicki, M, Alewijnse, L, Ohyama, W, Blumenstein, M & Found, B 1970, 'ICDAR 2013 Competitions on Signature Verification and Writer Identification for On- and Offline Skilled Forgeries (SigWiComp 2013)', 2013 12th International Conference on Document Analysis and Recognition, 2013 12th International Conference on Document Analysis and Recognition (ICDAR), IEEE, Washington, DC, USA, pp. 1477-1483.
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This paper presents the results of the ICDAR2013 competitions on signature verification and writer identification for on- and offline skilled forgeries jointly organized by PR researchers and Forensic Handwriting Examiners (FHEs). The aim is to bridge the gap between recent technological developments and forensic casework. Two modalities (signatures, and handwritten text) are considered where training and evaluation data (in Dutch and Japanese) were collected and provided by FHEs and PR-researchers. Four tasks were defined where the systems had to perform Dutch offline signature verification, Japanese offline signature verification, Japanese online signature verification, and Dutch writer identification. The participants of the signatures modality were motivated to report their results in Likelihood Ratios (LR). This has made the systems even more interesting for application in forensic casework. For evaluation of signatures modality, we used both the traditional Equal Error Rate (EER) and forensically substantial Cost of Log Likelihood Ratios (Cllr). The system having the smallest value of the Minimum Cost of Log Likelihood Ratio (Cllrmin) is declared winner. For evaluation of the handwritten text modality, we used the precision and accuracy measures and winners are announced on the basis of best F-measure value. © 2013 IEEE.
Mandal, R, Roy, PP, Pal, U & Blumenstein, M 1970, 'Signature segmentation and recognition from scanned documents', 2013 13th International Conference on Intellient Systems Design and Applications, 2013 13th International Conference on Intelligent Systems Design and Applications (ISDA), IEEE, Bangi, Malaysia, pp. 80-85.
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© 2013 IEEE. Signature as a query is important for content-based document image retrieval from a scanned document repository. This paper presents a two-stage approach towards automatic signature segmentation and recognition from scanned document images. In the first stage, signature blocks are segmented from the document using word-wise component extraction and classification. Gradient based features are extracted from each component at the word level to perform the classification task. In the 2nd stage, SIFT (Scale-Invariant Feature Transform) descriptors and Spatial Pyramid Matching (SPM)-based approaches are used for signature recognition. Support Vector Machines (SVMs) are employed as the classifier for both levels in this experiment. The experiments are performed on the publicly available 'Tobacco-800' and GPDS [1] datasets and the results obtained from the experiments are promising.
Mans, B & Mathieson, L 1970, 'On the Treewidth of Dynamic Graphs', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Springer Berlin Heidelberg, pp. 349-360.
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Dynamic graph theory is a novel, growing area that deals with graphs that change over time and is of great utility in modelling modern wireless, mobile and dynamic environments. As a graph evolves, possibly arbitrarily, it is challenging to identify the graph properties that can be preserved over time and understand their respective computability. In this paper we are concerned with the treewidth of dynamic graphs. We focus on metatheorems, which allow the generation of a series of results based on general properties of classes of structures. In graph theory two major metatheorems on treewidth provide complexity classifications by employing structural graph measures and finite model theory. Courcelle's Theorem gives a general tractability result for problems expressible in monadic second order logic on graphs of bounded treewidth, and Frick & Grohe demonstrate a similar result for first order logic and graphs of bounded local treewidth. We extend these theorems by showing that dynamic graphs of bounded (local) treewidth where the length of time over which the graph evolves and is observed is finite and bounded can be modelled in such a way that the (local) treewidth of the underlying graph is maintained. We show the application of these results to problems in dynamic graph theory and dynamic extensions to static problems. In addition we demonstrate that certain widely used dynamic graph classes naturally have bounded local treewidth. © 2013 Springer-Verlag Berlin Heidelberg.
Nemoto, K, Devitt, SJ, Trupke, M, Stephens, AM, Everitt, MS, Buczak, K, Noebauer, T, Schmiedmayer, J & Munro, WJ 1970, 'Quantum Device and Architecture based on NV Centers for Quantum Networks', CLEO: 2013, CLEO: QELS_Fundamental Science, OSA.
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In recent years, NV centers in diamond has attracted significant attention as a candidate for quantum information devices. The negatively charged NV center, in particular, has been intensely investigated [1-3]. NV- centers host both an electron spin qubit and a nitrogen nuclear spin, in our case a nuclear spin-1/2 of 15N is imbedded. The ground state of the electron spin qubit has a long coherence time and an optical transition at 637nm. The nuclear spins may be considered as a long-lived quantum memory, which has been experimentally demonstrated [2]. Because of these preferable quantum properties, NV centers have been considered as a good candidate for implementation of quantum information processing and there has been a number of theoretically propose designs for quantum information processing [3]. © 2013 The Optical Society.
Nemoto, K, Stephens, A, Devitt, S, Everitt, M, Schmiedmayer, J, Trupke, M, Saito, S, Matsuzaki, Y, SaiToh, A, Harrison, K & Munro, WJ 1970, 'Quantum communication utilizing cavity-based quantum devices', 2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR), 2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR), IEEE, Kyoto, JAPAN.
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Nemoto, K, Stephens, AM, Devitt, SJ, Harrison, KA & Munro, WJ 1970, 'The role of quantum memory in quantum information processing', SPIE Proceedings, SPIE Optical Engineering + Applications, SPIE, San Diego, CA.
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PAL, S, ALAEI, A, PAL, U & BLUMENSTEIN, M 1970, 'SVM AND NN BASED OFFLINE SIGNATURE VERIFICATION', International Journal of Computational Intelligence and Applications, World Scientific Pub Co Pte Lt, pp. 1340004-1340004.
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Among all of the biometric authentication systems, handwritten signatures are considered as the most legally and socially accepted attributes for personal verification. The objective of this paper is to present an empirical contribution toward the understanding of a threshold-based signature verification technique involving off-line Bangla (Bengali) signatures. Experiments on signature verification concerning non-English signatures are an important consideration in the signature verification area. Only very few research works employing signatures of Indian script have been considered in the field of non-English based signature verification. To fill this gap, a threshold-based scheme for the verification of off-line Bangla signatures is proposed. Some techniques such as under-sampled bitmap, intersection/end point and directional chain code are employed for feature extraction. The thresholds are computed based on the similarity measures obtained employing the nearest neighbor classifier. The SVM classifier has also been considered for mainly comparative experimental result generation. Furthermore, a Bangla signature database, which consists of 2400 (100 × 24) genuine signatures and 3000 (100 × 30) forgeries, has been created and is employed for experimentation. An average error rate (AER) of 12.33% was obtained as the best verification result using directional chain code features in this research work. As a comparative study, a different dataset (GPDS-160) has also been considered.
Pal, S, Pal, U & Blumenstein, M 1970, 'A Two-Stage Approach for English and Hindi Off-line Signature Verification', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on Image Analysis and Processing, Springer Berlin Heidelberg, Naples, Italy, pp. 140-148.
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The purpose of this paper is to present an empirical contribution towards the understanding of multi-script off-line signature identification and verification using a novel method involving off-line Hindi (Devnagari) and English signatures. The main aim of this approach is to demonstrate the significant advantage of the use of signature script identification in a multi-script signature verification environment. In the 1 st stage of the proposed signature verification technique a script identification technique is employed to know whether a signature is written in Hindi or English. In the second stage, a verification approach was explored separately for English signatures and Hindi signatures based on the script identification result. Different features like gradient feature, water reservoir feature, loop feature, aspect ratio etc. were employed, and Support Vector Machines (SVMs) were considered in our scheme. To get the comparative idea, multi-script signature verification results on the joint Hindi and English dataset without using any script identification technique is also computed. From the experiment results it is noted that we are able to reduce average error rate 4.81% more when script identification method is employed. © 2013 Springer-Verlag.
Pal, S, Pal, U & Blumenstein, M 1970, 'Hindi and English Off-line Signature Identification and Verification', Advances in Intelligent Systems and Computing, International Conference on Advances in Computing, Springer India, Bengaluru, Karnataka, India, pp. 905-910.
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Biometric systems play a significant role in the field of information security as they are extremely required for user authentication. Signature identification and verification have a great importance for authentication intention. The purpose of this paper is to present an empirical contribution towards the understanding of multi-script (Hindi and English) signature verification. This system will identify whether a claimed signature belongs to the group of English signatures or Hindi signatures from a combined Hindi and English signature datasets and then it will verify signatures using these two resultant signature datasets (Hindi script signature and English script signatures) separately. The modified gradient feature and SVM classifier were employed for identification and verification purposes. To the best of authors' knowledge, the multi-script signature identification and verification has never been used for the task of signature verification and this is the first report of using Hindi and English signatures in this area. Two different results for identification and verification are calculated and analysed. The accuracy of 98.05% is obtained for the identification of signature script using 2160 (1080 Hindi + 1080 English) samples for training and 1080 (540 Hindi + 540 English) samples for testing. The resultant data sets obtained in script identification of signatures were used for verification purpose. The FRR, FAR for Hindi and English was obtained 8.0%, 4.0% and 12.0%, 10.0% respectively. © 2013 Springer.
Pal, S, Pal, U & Blumenstein, M 1970, 'Multi-script off-line Signature verification: A two stage approach', CEUR Workshop Proceedings, International Workshop on Automated Forensic Handwriting Analysis, CEUR, Washington DC, USA, pp. 31-35.
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Signature identification and verification are of great importance in authentication systems. The purpose of this paper is to introduce an experimental contribution in the direction of multi-script off-line signature identification and verification using a novel technique involving off-line English, Hindi (Devnagari) and Bangla (Bengali) signatures. In the first evaluation stage of the proposed signature verification technique, the performance of a multi-script off-line signature verification system, considering a joint dataset of English, Hindi and Bangla signatures, was investigated. In the second stage of experimentation, multi-script signatures were identified based on the script type, and subsequently the verification task was explored separately for English, Hindi and Bangla signatures based on the identified script result. The gradient and chain code features were employed, and Support Vector Machines (SVMs) along with the Modified Quadratic Discriminate Function (MQDF) were considered in this scheme. From the experimental results achieved, it is noted that the verification accuracy obtained in the second stage of experiments (where a signature script identification method was introduced) is better than the verification accuracy produced following the first stage of experiments. Experimental results indicated that an average error rate of 20.80% and 16.40% were obtained for two different types of verification experiments.
Paler, A, Devitt, SJ, Nemoto, K & Polian, I 1970, 'Synthesis of Topological Quantum Circuits', Nanoscale Architectures (NANOARCH), 2012 IEEE/ACM International Symposium on (2012), Page(s): 181- 187, IEEE/ACM International Symposium on Nanoscale Architectures (NANOARCH), IEEE, Amsterdam, NETHERLANDS, pp. 181-187.
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Topological quantum computing has recently proven itself to be a verypowerful model when considering large- scale, fully error corrected quantumarchitectures. In addition to its robust nature under hardware errors, it is asoftware driven method of error corrected computation, with the hardwareresponsible for only creating a generic quantum resource (the topologicallattice). Computation in this scheme is achieved by the geometric manipulationof holes (defects) within the lattice. Interactions between logical qubits(quantum gate operations) are implemented by using particular arrangements ofthe defects, such as braids and junctions. We demonstrate that junction-basedtopological quantum gates allow highly regular and structured implementation oflarge CNOT (controlled-not) gate networks, which ultimately form the basis ofthe error corrected primitives that must be used for an error correctedalgorithm. We present a number of heuristics to optimise the area of theresulting structures and therefore the number of the required hardwareresources.
Qiao, Y, Sun, X & Yu, N 1970, 'Determinantal Complexities and Field Extensions', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Symposium on Algorithms and Computation, Springer Berlin Heidelberg, Hong Kong, pp. 119-129.
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Let double-struck F be a field of characteristic ≠ 2. The determinantal complexity of a polynomial P ∈ double-struck F[x1,..., x n] is defined as the smallest size of a matrix M whose entries are linear polynomials of xi 's over double-struck F, such that P = det(M) as polynomials in double-struck F[x1,..., xn]. To determine the determinantal complexity of the permanent polynomial is a long-standing open problem. Let double-struck K be an extension field of double-struck F; then P can be viewed as a polynomial over double-struck K. We are interested in the comparison between the determinantal complexity of P over double-struck K (denoted as dcdouble-struck K(P))), and that of P over double-struck F (denoted as dcdouble-struck F(P). It is clear that dcdouble-struck K(P) ≤, dcdouble-struck F(P) and the question is whether strict inequality can happen. In this note we consider polynomials defined over ℚ. For P = x12 + ⋯ + xn2, there exists a constant multiplicative gap between dcℝ(P) and dcℂ(P): we prove dc ℝ(P) ≥ n while ⌈n/2⌉ + 1 ≥ dc ℂ(P). We also consider additive constant gaps: (1) there exists a quadratic polynomial Q ∈ ℚ [x, y], such that dcℚ-(Q) = 3 and ; (2) there exists a cubic polynomial C ∈ ℚ[x, y] with a rational zero, such that dcℚ(C) = 4 and dcℚ-(C) = 3. For additive constant gaps, geometric criteria are presented to decide when dcℚ = dcℚ-. © 2013 Springer-Verlag.
Sharma, N, Chanda, S, Pal, U & Blumenstein, M 1970, 'Word-Wise Script Identification from Video Frames', 2013 12th International Conference on Document Analysis and Recognition, 2013 12th International Conference on Document Analysis and Recognition (ICDAR), IEEE, Washington, DC, USA, pp. 867-871.
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Script identification is an essential step for the efficient use of the appropriate OCR in multilingual document images. There are various techniques available for script identification from printed and handwritten document images, but script identification from video frames has not been explored much. This paper presents a study of some pre-processing techniques and features for word-wise script identification from video frames. Traditional features, namely Zernike moments, Gabor and gradient, have performed well for handwritten and printed documents having simple backgrounds and adequate resolution for OCR. Video frames are mostly coloured and suffer from low resolution, blur, background noise, to mention a few. In this paper, an attempt has been made to explore whether the traditional script identification techniques can be useful in video frames. Three feature extraction techniques, namely Zernike moments, Gabor and gradient features, and SVM classifiers were considered for analyzing three popular scripts, namely English, Bengali and Hindi. Some pre-processing techniques such as super resolution and skeletonization of the original word images were used in order to overcome the inherent problems with video. Experiments show that the super resolution technique with gradient features has performed well, and an accuracy of 87.5% was achieved when testing on 896 words from three different scripts. The study also reveals that the use of proper pre-processing approaches can be helpful in applying traditional script identification techniques to video frames. © 2013 IEEE.
Sharma, N, Shivakumara, P, Pal, U, Blumenstein, M & Tan, CL 1970, 'A New Method for Character Segmentation from Multi-oriented Video Words', 2013 12th International Conference on Document Analysis and Recognition, 2013 12th International Conference on Document Analysis and Recognition (ICDAR), IEEE, USA, pp. 413-417.
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This paper presents a two-stage method for multi-oriented video character segmentation. Words segmented from video text lines are considered for character segmentation in the present work. Words can contain isolated or non-touching characters, as well as touching characters. Therefore, the character segmentation problem can be viewed as a two stage problem. In the first stage, text cluster is identified and isolated (non-touching) characters are segmented. The orientation of each word is computed and the segmentation paths are found in the direction perpendicular to the orientation. Candidate segmentation points computed using the top distance profile are used to find the segmentation path between the characters considering the background cluster. In the second stage, the segmentation results are verified and a check is performed to ascertain whether the word component contains touching characters or not. The average width of the components is used to find the touching character components. For segmentation of the touching characters, segmentation points are then found using average stroke width information, along with the top and bottom distance profiles. The proposed method was tested on a large dataset and was evaluated in terms of precision, recall and f-measure. A comparative study with existing methods reveals the superiority of the proposed method. © 2013 IEEE.
Tomamichel, M & Tan, VYF 1970, 'ε-Capacity and strong converse for channels with general state', 2013 IEEE Information Theory Workshop (ITW), 2013 IEEE Information Theory Workshop (ITW 2013), IEEE, Seville, Spain.
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We consider state-dependent memoryless channels with general state available at both encoder and decoder. We establish the ε-capacity and the optimistic ε-capacity. This allows us to prove a necessary and sufficient condition for the strong converse to hold. We also provide a simpler sufficient condition on the first- and second-order statistics of the state process that ensures that the strong converse holds.
Tomamichel, M & Tan, VYF 1970, 'A tight upper bound for the third-order asymptotics of discrete memoryless channels', 2013 IEEE International Symposium on Information Theory, 2013 IEEE International Symposium on Information Theory (ISIT), IEEE, pp. 1536-1540.
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This paper shows that the logarithm of the ε-error capacity (average error probability) for n uses of a discrete memoryless channel with positive conditional information variance at every capacity-achieving input distribution is upper bounded by the normal approximation plus a term that does not exceed 1/2 log n + O(1). © 2013 IEEE.
Tomamichel, M, Fehr, S, Kaniewski, J & Wehner, S 1970, 'One-Sided Device-Independent QKD and Position-Based Cryptography from Monogamy Games', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on the Theory and Application of Cryptographic Techniques, Springer Berlin Heidelberg, Athens, Greece, pp. 609-625.
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A serious concern with quantum key distribution (QKD) schemes is that, when under attack, the quantum devices in a real-life implementation may behave differently than modeled in the security proof. This can lead to real-life attacks against provably secure QKD schemes. In this work, we show that the standard BB84 QKD scheme is one-sided device-independent. This means that security holds even if Bob's quantum device is arbitrarily malicious, as long as Alice's device behaves as it should. Thus, we can completely remove the trust into Bob's quantum device for free, without the need for changing the scheme, and without the need for hard-to-implement loophole-free violations of Bell inequality, as is required for fully (meaning two-sided) device-independent QKD. For our analysis, we introduce a new quantum game, called a monogamy-of-entanglement game, and we show a strong parallel repetition theorem for this game. This new notion is likely to be of independent interest and to find additional applications. Indeed, besides the application to QKD, we also show a direct application to position-based quantum cryptography: we give the first security proof for a one-round position-verification scheme that requires only single-qubit operations. © 2013 International Association for Cryptologic Research.
Wi, H, Nguyen, V, Lee, J, Guan, H, Loo, YC & Blumenstein, M 1970, 'Enhancing visual-based bridge condition assessment for concrete crack evaluation using image processing techniques', Long Span Bridges and Roofs - Development, Design and Implementation, IABSE Symposium, Kolkata, India.
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Condition assessment is one of the most essential practices in bridge asset management to maintain the safety and durability of structures. Routine bridge inspection, a visual-based method, is regularly performed by qualified inspectors to determine the condition of individual bridge elements manually using bridge inspection standards. However, the quality of a visual-based condition assessment relies heavily on the inspector's knowledge and experience. The research presented here focuses on the development of an enhanced method to minimise the shortcomings of visual-based inspection. In this paper, we investigate the performance of RBF-kernel support vector machines (SVMs), a supervised machine learning technique, to increase the reliability of visual-based bridge inspection. The results of this study can contribute to minimising the shortcomings of current visual-based bridge inspection practices.
Wi, H, Nguyen, V, Lee, J, Guan, H, Loo, Y-C & Blumenstein, M 1970, 'Enhancing Visual-based Bridge Condition Assessment for Concrete Crack Evaluation Using Image Processing Techniques', IABSE Symposium, Kolkata 2013: Long Span Bridges and Roofs - Development, Design and Implementation, IABSE Symposium, Kolkata 2013: Long Span Bridges and Roofs - Development, Design and Implementation, International Association for Bridge and Structural Engineering (IABSE).
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<p>Condition assessment is one of the most essential practices in bridge asset management to maintain the safety and durability of structures. Routine bridge inspection, a visual-based method, is regularly performed by qualified inspectors to determine the condition of individual bridge elements manually using bridge inspection standards. However, the quality of a visual-based condition assessment relies heavily on the inspector’s knowledge and experience. The research presented here focuses on the development of an enhanced method to minimise the shortcomings of visual-based inspection. In this paper, we investigate the performance of RBF-kernel support vector machines (SVMs), a supervised machine learning technique, to increase the reliability of visual- based bridge inspection. The results of this study can contribute to minimising the shortcomings of current visual-based bridge inspection practices.</p>
Ying, M, Feng, Y, Yu, N & IEEE 1970, 'Quantum Information-Flow Security: Noninterference and Access Control', 2013 IEEE 26TH COMPUTER SECURITY FOUNDATIONS SYMPOSIUM (CSF), IEEE Computer Security Foundations Symposium, IEEE Computer Society, Tulane University, New Orleans, Louisiana, USA, pp. 130-144.
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Quantum cryptography has been extensively studied in the last twenty years, but information-flow security of quantum computing and communication systems has been almost untouched in the previous research. Due to the essential difference between classical and quantum systems, formal methods developed for classical systems, including probabilistic systems, cannot be directly applied to quantum systems. This paper defines an automata model in which we can rigorously reason about information-flow security of quantum systems. The model is a quantum generalisation of Goguen and Meseguer's noninterference. The unwinding proof technique for quantum noninterference is developed, and a certain compositionality of security for quantum systems is established. The proposed formalism is then used to prove security of access control in quantum systems. © 2013 Authors, as per new IEEE copyright agreement.
Ying, S, Feng, Y, Yu, N & Ying, M 1970, 'Reachability Probabilities of Quantum Markov Chains', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on Concurrency Theory, Springer, University of Buenos Aires, Argentina, pp. 334-348.
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This paper studies three kinds of long-term behaviours, namely reachability,repeated reachability and persistence, of quantum Markov chains (qMCs). As astepping-stone, we introduce the notion of bottom strongly connected component(BSCC) of a qMC and develop an algorithm for finding BSCC decompositions of thestate space of a qMC. As the major contribution, several (classical) algorithmsfor computing the reachability, repeated reachability and persistenceprobabilities of a qMC are presented, and their complexities are analysed.
