Trivium is a synchronous stream cipher using three shift registers. It is designed to have a simple structure and runs at high speed. A scan-based side-channel attack retrieves secret information using scan chains, one of design-for-test techniques. In this paper, a scan-based side-channel attack method against Trivium using scan signatures is proposed. In our method, we reconstruct a previous internal state in Trivium one by one from the internal state just when a ciphertext is generated. When we retrieve the internal state, we focus on a particular 1-bit position in a collection of scan chains and then we can attack Trivium even if the scan chain includes other registers than internal state registers in Trivium. Experimental results show that our proposed method successfully retrieves a plaintext from a ciphertext generated by Trivium.

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This paper presents a novel test data compression scheme for SoCs based on block merging and compatibility. The technique exploits the properties of compatibility and inverse compatibility between consecutive blocks, consecutive merged blocks, and two halves of the encoding merged block itself to encode the pre-computed test data. The decompression circuit is simple to be implemented and has advantage of test-independent. In addition, the proposed scheme is applicable for IP cores in SoCs since it compresses the test data without requiring any structural information of the circuit under test. Experimental results demonstrate that the proposed technique can achieve an average compression ratio up to 68.02% with significant low test application time.

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This paper presents a measurement circuit structure for capturing SET pulse-width suppressing pulse-width modulation and within-die process variation effects. For mitigating pulse-width modulation while maintaining area efficiency, the proposed circuit uses massively parallelized short inverter chains as a target circuit. Moreover, for each inverter chain on each die, pulse-width calibration is performed. In measurements, narrow SET pulses ranging 5ps to 215ps were obtained. We confirm that an overestimation of pulse-width may happen when ignoring die-to-die and within-die variation of the measurement circuit. Our evaluation results thus point out that calibration for within-die variation in addition to die-to-die variation of the measurement circuit is indispensable.

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Fault tolerant methods using dynamically reconfigurable devices have been studied to overcome wear-out failures. However, quantitative comparisons have not been sufficiently assessed on device lifetime enhancement with these methods, whereas they have mainly been evaluated individually from various viewpoints such as additional hardware overheads, performance, and downtime for fault recovery. This paper presents quantitative lifetime evaluations performed by simulating the fault-avoidance procedures of five representative methods under the same conditions in wear-out scenarios, applications, and device architecture. The simulation results indicated that improvements of up to 70% mean-time-to-failure (MTTF) in comparison with ideal fault avoidance could be achieved by using methods of fault avoidance with ‘row direction shift’ and ‘dynamic partial reconfiguration’. ‘Column shift’, on the other hand, attained a high degree of stability with moderate improvements in MTTF. The experimental results also revealed that spare basic elements (BEs) should be prevented from aging so that improvements in MTTF would not be adversely affected. Moreover, we found that the selection of initial mappings guided by wire utilization could increase the lifetimes of partial reconfiguration based fault avoidance.

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Negative Bias Temperature Instability (NBTI) is one of the serious concerns for long-term circuit performance degradation. NBTI degrades PMOS transistors under negative bias, whereas they recover once negative bias is removed. In this paper, we propose a mitigation method for NBTI-induced performance degradation that exploits the recovery property by shifting random input sequence through scan paths. With this method, we prevent consecutive stress that causes large degradation. Experimental results reveal that random scan-in vectors successfully mitigate NBTI and the path delay degradation is reduced by 71% in a test case when standby mode occupies 10% of total time. We also confirmed that 8-bit LFSR is capable of random number generation for this purpose with low area and power overhead.

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This paper reduces the total number of lifting steps of a two dimensional (2D) discrete wavelet transform (DWT) under the constraint that the DWT has full compatibility with a given separable 2D DWT. In a DWT composed of several lifting steps in cascade, a lifting step must wait for a calculation result of its previous lifting step. Therefore more lifting steps bring about longer latency from the input to the output. In this paper, we reduce the total number of lifting steps of a quadruple lifting DWT which is widely utilized as the 9/7 DWT in the JPEG 2000 international standard for image data compression. Firstly, we introduce basic properties for modification of signal flow structure inside a DWT without changing its output. Secondly, we convert the separable 2D quadruple lifting DWT into the non-separable 2D DWT utilizing the basic properties so that the total number of the lifting steps is reduced. As a result, the lifting steps were reduced to 75[%]. Finally, we evaluate the proposed non-separable 2D DWT in respect of compatibility with the conventional separable 2D DWT.

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In this paper, we consider a similarity control problem for plants and specifications, modeled as nondeterministic automata. This problem requires us to synthesize a nondeterministic supervisor such that the supervised plant is simulated by a given specification. We assume that a supervisor can observe not only the event occurrence but also the current state of the plant. First, we derive a necessary and sufficient condition for the existence of a complete supervisor, which is a solution to the similarity control problem. Then, we present a method for synthesizing a maximally permissive similarity enforcing supervisor when the existence condition is satisfied.

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This paper studies spike-train dynamics of the bifurcating neuron and its pulse-coupled system. The neuron has periodic base signal that is given by applying a periodic square wave to a basic low-pass filter. As key parameters of the filter vary, the systems can exhibit various bifurcation phenomena. For example, the neuron exhibits period-doubling bifurcation through which the period of spike-train is doubling. The coupled system exhibits two kinds of (smooth and non-smooth) tangent bifurcations that can induce “chaos + chaos = order”: chaotic spike-trains of two neurons are changed into periodic spike-train by the pulse-coupling. Using the mapping procedure, the bifurcation phenomena can be analyzed precisely. Presenting simple test circuits, typical phenomena are confirmed experimentally.

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In this paper, we first prove beyond-birthyday-bound security for the Misty structure. Specifically, we show that an r-round Misty structure is secure against CCA attacks up to $O(2^{\frac{rn}{r+7}})$ query complexity, where n is the size of each round permutation. So for any ε>0, a sufficient number of rounds would guarantee the security of the Misty structure up to 2^n(1-ε) query complexity.

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This paper presents a new information-theoretical evaluation method, for the resistance of cryptographic implementation against side-channel attacks. In conventional methods, the results of actual attacks have been often used empirically. However, these experimental methods have some problems. In the proposed method, a side-channel attack is regarded as a communication channel model. Then, a new evaluation index “the amount of leakage information” can be defined. The upper-bound of this index is estimated as the channel capacity. The proposed evaluation using this index can avoid the problems of conventional methods. Consequently, the proposed method provides some benefits: (1) It provides rationale for evaluation; (2) It enables execution of numerical evaluation and mutual evaluation among several kinds of countermeasures. This research achieves a unification of evaluation indexes for resistance against side-channel attack. This paper applies the proposed method to correlation power analysis against implementations of stream cipher Enocoro-128 v2. As a result, we confirmed its effectiveness.

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We consider some attacks on multi-prime RSA (MPRSA) with a modulus N = p₁p₂ . . . p_r (r ≥ 3). It is believed that the small private exponent attack on the MPRSA is less effective than that on RSA (see Hinek et al.'s work at SAC 2003), which means smaller private exponents can be used in the MPRSA to speed up the decryption process. Our work shows that even if a private exponent is significantly beyond Hinek et al.'s bound, it still may be insecure if the prime difference Δ (Δ = p_r - p₁ = N^γ, supposing p₁ < p₂ < … < p_r) is small, i.e. 0 < γ < 1/r. Specifically, by taking full advantage of prime properties, our small private exponent attack reveals that the MPRSA is insecure when $\delta<1-\sqrt{1+2\gamma-3/r}$ (if $\gamma\ge\frac{3}{2r}-\frac{1+\delta}{4}$) or $\delta\le \frac{3}{r}-\frac{1}{4}-2\gamma$ (if $\gamma < \frac{3}{2r}-\frac{1+\delta}{4}$), where δ is the exponential of the private exponent d with base N, i.e., d = N^δ. In addition, we present a Fermat-like factoring attack which factors N efficiently when Δ < N^1/r2. These proposed attacks surpass previous works (e.g. Bahig et al.'s at ICICS 2012), and are proved effective in practice.

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The k-error linear complexity of periodic sequences is an important security index of stream cipher systems. By using an interesting decomposing approach, we investigate the intrinsic structure for the set of 2ⁿ-periodic binary sequences with fixed complexity measures. For k ≤ 4, we construct the complete set of error vectors that give the k-error linear complexity. As auxiliary results we obtain the counting functions of the k-error linear complexity of 2ⁿ-periodic binary sequences for k ≤ 4, as well as the expectations of the k-error linear complexity of a random sequence for k ≤ 3. Moreover, we study the 2^t-error linear complexity of the set of 2ⁿ-periodic binary sequences with some fixed linear complexity L, where t < n-1 and the Hamming weight of the binary representation of 2ⁿ-L is t. Also, we extend some results to pⁿ-periodic sequences over F_p. Finally, we discuss some potential applications.

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In this paper, we propose a new encoding method applicable to any linear codes over arbitrary finite field whose computational complexity is O(δ^*n) where δ^* and n denote the maximum column weight of a parity check matrix of a code and the code length, respectively. This means that if a code has a parity check matrix with the constant maximum column weight, such as LDPC codes, it can be encoded with O(n) computation. We also clarify the relation between the proposed method and conventional methods, and compare the computational complexity of those methods. Then we show that the proposed encoding method is much more efficient than the conventional ones.

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A novel class of signal of perfect Gaussian integer sequence pairs are put forward in this paper. The constructions of obtaining perfect Gaussian integer sequence pairs of odd length by using Chinese remainder theorem as well as perfect Gaussian integer sequence pairs of even length by using complex transformation and interleaving techniques are presented. The constructed perfect Gaussian integer sequence pairs can not only expand the existence range of available perfect Gaussian integer sequences and perfect sequence pairs signals but also overcome the energy loss defects.

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This paper proposes a new spectrum sharing scheme which uses one-sided collaboration. In the proposed system, the transmitter of the secondary system relays the primary signal and overlays its own data on the retransmitted primary signal. The results of the theoretical analysis show that the proposed scheme with regenerative relay allows the secondary system to communicate at the same speed as the primary system that disregards the presence of the secondary system.

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This paper proposes a so called quasi-linear support vector machine (SVM), which is an SVM with a composite quasi-linear kernel. In the quasi-linear SVM model, the nonlinear separation hyperplane is approximated by multiple local linear models with interpolation. Instead of building multiple local SVM models separately, the quasi-linear SVM realizes the multi local linear model approach in the kernel level. That is, it is built exactly in the same way as a single SVM model, by composing a quasi-linear kernel. A guided partitioning method is proposed to obtain the local partitions for the composition of quasi-linear kernel function. Experiment results on artificial data and benchmark datasets show that the proposed method is effective and improves classification performances.

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Detailed high capacity vector maps must be compressed effectively for transmission or storage in Web GIS (geographic information system) and mobile GIS applications. In this paper, we present a polyline compression method that consists of polyline feature-based hybrid simplification and second derivative-based data compression. The polyline hybrid simplification function detects the feature points from a polyline using DP, SF, and TF algorithms, and divides the polyline into sectors using these feature points. It then simplifies the sectors using an algorithm to determine the minimum area difference among the DP, SF, and TF results. The polyline data compression method segments the second derivatives of the simplified polylines into integer and fractional parts. The integer parts are compressed using the minimum bounding box of the layer to determine the broad position of the object. The fractional parts are compressed using hierarchical precision levels. Experimental results verify that our method has higher simplification and compression efficiency than conventional methods and produces good quality compressed maps.

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In this paper, we study conjunctive decentralized diagnosis of discrete event systems (DESs). In most existing works on decentralized diagnosis of DESs, it is implicitly assumed that diagnosis decisions of all local diagnosers are available to detect a failure. However, it may be possible that some local diagnosis decisions are not available, due to some reasons. Letting n be the number of local diagnosers, the notion of (n,k)-conjunctive codiagnosability guarantees that the occurrence of any failure is detected in the conjunctive architecture as long as at least k of the n local diagnosis decisions are available. We propose an algorithm for verifying (n,k)-conjunctive codiagnosability. To construct a reliable conjunctive decentralized diagnoser, we need to compute the delay bound within which the occurrence of any failure can be detected as long as at least k of the n local diagnosis decisions are available. We show how to compute the delay bound.

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Acoustic feedback is a major complaint of hearing aid users. Adaptive filters are a common method for suppressing acoustic feedback in digital hearing aids. In this letter, we propose a new variable step-size algorithm for normalized least mean square and an affine projection algorithm to combine with a variable step-size affine projection algorithm and global speech absence probability in an adaptive filter. The computer simulation used to test the proposed algorithm results in a lower misalignment error than the comparison algorithm at a similar convergence rate. Therefore, the proposed algorithm suggests an effective solution for the feedback suppression system of digital hearing aids.

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In this study, a performance of a synchronous code division multiple access (CDMA) using the chaotic spreading sequences with constant power is estimated in indoor power line fading channels. It is found that, in the fading channels, as the number of simultaneous users increases, the chaotic spreading sequences realize better performance than the Walsh-Hadamard sequences in the synchronous CDMA.

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An echo-hiding scheme is presented to detect the pitch variation due to playback speed modification. The inserted time-spread echo is obtained by convolving the highpass filtered audio with a gain-controlled pseudo noise sequence. The perceptual evaluation confirms that the embedded echo is virtually imperceptible. Compared with the Fourier magnitude modulation, the proposed scheme attains better detection rates.

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In this paper, the linear complexity and minimal polynomials of Legendre sequences over F_q have been calculated, where q = p^m and p is a prime number. Our results show that Legendre sequences have high linear complexity over F_q for a large part of prime power number q so that they can resist the linear attack method.

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Based on the non-standard generalized Boolean functions (GBFs) over Z₄, we propose a new method to convert those functions into the 16-QAM Golay complementary sequences (CSs). The resultant 16-QAM Golay CSs have the upper bound of peak-to-mean envelope power ratio (PMEPR) as low as 2. In addition, we obtain multiple 16-QAM Golay CSs for a given quadrature phase shift keying (QPSK) Golay CS.

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The development of 3D High Efficiency Video Coding (3D-HEVC) has resulted in a growing interest in the compression of depth-maps. To achieve better intra prediction performance, the Depth Modeling Mode (DMM) technique is employed as an intra prediction technique for depth-maps. However, the complexity and computation load have dramatically increased with the application of DMM. Therefore, in view of the limited colors in depth-maps, this paper presents a novel fast intra coding scheme based on Base Colors and Index Map (BCIM) to reduce the complexity of DMM effectively. Furthermore, the index map is remapped, and the Base Colors are coded by predictive coding in BCIM to improve compression efficiency. Compared with the intra prediction coding in DMM, the experimental results illustrate that the proposed scheme provides a decrease of approximately 51.2% in the intra prediction time. Meanwhile, the BD-rate increase is only 0.83% for the virtual intermediate views generated by Depth-Image-Based Rendering.

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In this letter, a novel antenna selection (AS) technique is proposed for the downlink of large-scale multi-user multiple input multiple output (MU-MIMO) networks, where a base station (BS) is equipped with large-scale antennas (N) and communicates simultaneously with K(K ≪ N) mobile stations (MSs). In the proposed scheme, the S antennas (S ≤ N) are selected by utilizing the concept of a sliding window. It is shown that the sum-rate of our proposed scheme is comparable to that of the conventional scheme, while the proposed scheme can significantly reduce the complexity of the BS.

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A maximum-likelihood code acquisition scheme is investigated for frequency-selective fading channels with an emphasis on the decision strategies. Using the maximum-likelihood estimation technique, we first derive an optimal decision rule, which is optimal in the viewpoint of probability of detection. Based on the derived optimal decision rule, a practical and simple decision rule is also developed, and its performance is assessed for both single dwell and double dwell acquisition systems. Simulation results demonstrate that the proposed acquisition scheme significantly outperforms the previously proposed schemes in frequency-selective fading channels.

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In this letter, the k-out-of-n rule for cooperative sensing is considered. For a given n, we derive the optimal value of k that minimizes the total sensing error probability subject to the sensing accuracy, considering both the effective of sensing errors and the primary activities. According to the optimal k, we analyze the performance and compare with other schemes, which illustrate the effectiveness of the proposed scheme.

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In this letter, a new sparse locality preserving projection (SLPP) algorithm is developed and applied to facial expression recognition. In comparison with the original locality preserving projection (LPP) algorithm, the presented SLPP algorithm is able to simultaneously find the intrinsic manifold of facial feature vectors and deal with facial feature selection. This is realized by the use of l₁-norm regularization in the LPP objective function, which is directly formulated as a least squares regression pattern. We use two real facial expression databases (JAFFE and Ekman's POFA) to testify the proposed SLPP method and certain experiments show that the proposed SLPP approach respectively gains 77.60% and 82.29% on JAFFE and POFA database.

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We analyze the defects of window-based TCP algorithm in datacenter networks and propose Rate-based Datacenter TCP (RDT) algorithm in this paper. The RDT algorithm combines rate-based congestion control technology with ECN (Explicit Congestion Notification) mechanism of DCTCP. The experiments in NS2 show that RDT has a potential to completely avoid TCP incast collapse in datacenters and inherit the low latency advantages of DCTCP.

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