Two spanning trees T1,T2 of a graph G = (V,E) are independent if they are rooted at the same vertex, say r, and for each vertex v ∈ V, the path from r to v in T1 and the path from r to v in T2 have no common vertices and no common edges except for r and v. In general, spanning trees T1,T2,…,Tk of a graph G = (V,E) are independent if they are pairwise independent. A graph G = (V,E) is called a 2-chordal ring and denoted by CR(N,d1,d2), if V = {0,1,…,N-1} and E = {(u,v)|[v-u]N = 1 or [v-u]N = d1 or [v-u]N = d2, 2 ≤ d1 < d2 ≤ N/2}. CR(N,d1,N/2) is 5-connected if N ≥ 8 is even and d1 ≠ N/2-1. We give an algorithm to construct 5 independent spanning trees of CR(N,d1,N/2),N ≥ 8 is even and 2 ≤ d1 ≤ ⌈N/4⌉.

A 12×16-element corporate-feed slot array is presented. The corporate-feed circuit for the 12×16-elemtent array consists of cross-junctions and asymmetric T-junctions, whereas the conventional one is limited to arrays of 2m×2n slots by its use of symmetric T-junctions. Simulations of the 12×16-element array show a 7.6% bandwidth for reflection less than -14dB. A 31.7-dBi gain with an antenna efficiency of 82.6% is obtained at the design frequency of 61.5GHz. The 12×16-element array is fabricated by diffusion bonding of laminated thin metal plates. Measurements indicate 31.1-dBi gain with 71.9% antenna efficiency at 61.5GHz.

This paper proposes an analytical, closed-form AC-DC voltage multiplier model and investigates the dependency of output current and input power on circuit and device parameters. The model uses no fitting parameters and a frequency term applicable to both multipliers using diodes and metal-oxide semiconductor field effect transistors (MOSFETs). Analysis enables circuit designers to estimate circuit parameters, such as the number of stages and capacitance per stages, and device parameters such as saturation current (in the case of diodes) or transconductance (in the case of MOSFETs). Comparisons of the proposed model with SPICE simulation results as well as other models are also provided for validation. In addition, design optimizations and the impact of AC power source impedance on output power are also investigated.

In this letter, we show the recursive representation of the optimum projection matrix. The recursive representation of the orthogonal projection and oblique projection have been done in past references. These projections are optimum when the noise is only characterized by the white noise or the structured noise. However, in some practical applications, a desired signal is deteriorated by both the white noise and structured noise. In this situation, the optimum projection matrix has been given by Behrens. For this projection matrix, the recursive representation has not been done. Therefore, in this letter, we propose the recursive representation of this projection matrix.

An algorithm that finds a set of real-valued approximately-zero correlation zone (AZCZ) sequences is proposed on the basis of the concept of feedback-controlled direct-sequence code-division multiple access (FC/DS-CDMA). It is known that ordinary algorithms can construct low correlation zone (LCZ) and zero correlation zone (ZCZ) sequence sets in which the choices of the number of sequences, sequence length, and LCZ or ZCZ length are limited. It is shown that the proposed algorithm finds AZCZ sequence sets by a numerical method under arbitrary conditions. The properties of AZCZ sequence sets are evaluated in terms of the autocorrelation and cross-correlation functions. It is shown that the periodic autocorrelation and cross-correlation functions take small values within a designated AZCZ. It is also shown that we can construct approximately-perfect sequences that have approximately ideal autocorrelation functions and new sequence sets that have multiple AZCZs using the proposed algorithm.

This letter describes a speech enhancement algorithm for stereo signals corrupted by diffuse noise. It estimates the noise signal and also a beamformed target signal based on blind target signal cancelation derived from sparsity minimization. Enhanced target speech is obtained by Wiener filtering using both the signals. Experimental results demonstrate the effectiveness of the proposed method.

This paper presents the first non-trivial collision attack on the double-block-length compression function presented at FSE 2006 instantiated with round-reduced AES-256: f0(h0||h1,M)||f1(h0||h1,M) such that f0(h0||h1, M) = Eh1||M(h0)⊕h0 , f1(h0||h1,M) = Eh1||M(h0⊕c)⊕h0⊕c , where || represents concatenation, E is AES-256 and c is a 16-byte non-zero constant. The proposed attack is a free-start collision attack using the rebound attack proposed by Mendel et al. The success of the proposed attack largely depends on the configuration of the constant c: the number of its non-zero bytes and their positions. For the instantiation with AES-256 reduced from 14 rounds to 8 rounds, it is effective if the constant c has at most four non-zero bytes at some specific positions, and the time complexity is 264 or 296. For the instantiation with AES-256 reduced to 9 rounds, it is effective if the constant c has four non-zero bytes at some specific positions, and the time complexity is 2120. The space complexity is negligible in both cases.

Analogy-based software effort estimation has gained a considerable amount of attention in current research and practice. Its excellent estimation accuracy relies on its solution adaptation stage, where an effort estimate is produced from similar past projects. This study proposes a solution adaptation technique named LSA-X that introduces an approach to exploit the potential of productivity factors, i.e., project variables with a high correlation with software productivity, in the solution adaptation stage. The LSA-X technique tailors the exploitation of the productivity factors with a procedure based on the Linear Size Adaptation (LSA) technique. The results, based on 19 datasets show that in circumstances where a dataset exhibits a high correlation coefficient between productivity and a related factor (r≥0.30), the proposed LSA-X technique statistically outperformed (95% confidence) the other 8 commonly used techniques compared in this study. In other circumstances, our results suggest using any linear adaptation technique based on software size to compensate for the limitations of the LSA-X technique.

In recent times, wireless Local Area Networks (wireless LANs) based on the IEEE 802.11 standard have been spreading rapidly, and connecting to the Internet using wireless LANs has become more common. In addition, public wireless LAN service areas, such as train stations, hotels, and airports, are increasing and tethering technology has enabled smartphones to act as access points (APs). Consequently, there can be multiple APs in the same area. In this situation, users must select one of many APs. Various studies have proposed and evaluated many AP selection methods; however, existing methods do not consider AP mobility. In this paper, we propose an AP selection method based on cooperation among APs and user movement. Moreover, we demonstrate that the proposed method dramatically improves throughput compared to an existing method.

Non-volatile memory has many advantages such as high density and low leakage power but it consumes larger writing energy than SRAM. It is quite necessary to reduce writing energy in non-volatile memory design. In this paper, we propose write-reduction codes based on error correcting codes and reduce writing energy in non-volatile memory by decreasing the number of writing bits. When a data is written into a memory cell, we do not write it directly but encode it into a codeword. In our write-reduction codes, every data corresponds to an information vector in an error-correcting code and an information vector corresponds not to a single codeword but a set of write-reduction codewords. Given a writing data and current memory bits, we can deterministically select a particular write-reduction codeword corresponding to the data to be written, where the maximum number of flipped bits are theoretically minimized. Then the number of writing bits into memory cells will also be minimized. Experimental results demonstrate that we have achieved writing-bits reduction by an average of 51% and energy reduction by an average of 33% compared to non-encoded memory.

8K Ultra High Definition Television (UHDTV) requires extremely high throughput for video decoding based on H.265. In H.265, intra coding could significantly enhance video compression efficiency, at the expense of an increased computational complexity compared with H.264. For intra prediction of 8K UHDTV real-time H.265 decoding, the joint complexity and throughput issue is more difficult to solve. Therefore, based on the divide-and-conquer strategy, we propose a new VLSI architecture in this paper, including two techniques, in order to achieve 8K UHDTV H.265 intra prediction decoding. The first technique is the LUT based Reference Sample Fetching Scheme (LUT-RSFS), reducing the number of reference samples in the worst case from 99 to 13. It further reduces the circuit area and enhances the performance. The second one is the Hybrid Block Reordering and Data Forwarding (HBRDF), minimizing the idle time and eliminating the dependency between TUs by creating 3 Data Forwarding paths. It achieves the hardware utilization of 94%. Our design is synthesized using Synopsys Design Compiler in 40nm process technology. It achieves an operation frequency of 260MHz, with a gate count of 217.8K for 8-bit design, and 251.1K for 10-bit design. The proposed VLSI architecture can support 4320p@120fps H.265 intra decoding (8-bit or 10-bit), with all 35 intra prediction modes and prediction unit sizes ranging from 4×4 to 64×64.

This letter investigates the circularity of fractional Fourier transform (FRFT) coefficients containing noise only, and proves that all coefficients coming from white Gaussian noise are circular via the discrete FRFT. In order to use the spectrum kurtosis (SK) as a Gaussian test to check if linear frequency modulation (LFM) signals are present in a set of FRFT points, the effect of the noncircularity of Gaussian variables upon the SK of FRFT coefficients is studied. The SK of the α th-order FRFT coefficients for LFM signals embedded in a white Gaussian noise is also derived in this letter. Finally the signal detection algorithm based on FRFT and SK is proposed. The effectiveness and robustness of this algorithm are evaluated via simulations under lower SNR and weaker components.

The purpose of this work is to reduce the redundant coding process with the tradeoff between the encoding complexity and coding efficiency in HEVC, especially for high resolution applications. Therefore, a CU depth prediction algorithm is proposed for motion estimation process of HEVC. At first, an efficient CTU depth prediction algorithm is proposed to reduce redundant depth. Then, CU size termination and skip algorithm is proposed based on the neighboring block depth and motion consistency. Finally, the overall algorithm, which has excellent complexity reduction performance for high resolution application is proposed. Moreover, the proposed method achieves steady performance, and it can significantly reduce the encoding time in different environment configuration and quantization parameter. The simulation experiment results demonstrate that, in the RA case, the average time saving is about 56% with only 0.79% BD-bitrate loss for the high resolution, and this performance is better than the previous state of the art work.

Intelligent information systems captivate people's attention. Examples of such systems include driving support vehicles capable of sensing driver state and communication robots capable of interacting with humans. Modeling how people search visual information is indispensable for designing these kinds of systems. In this paper, we focus on human visual attention, which is closely related to visual search behavior. We propose a computational model to estimate human visual attention while carrying out a visual target search task. Existing models estimate visual attention using the ratio between a representative value of visual feature of a target stimulus and that of distractors or background. The models, however, can not often achieve a better performance for difficult search tasks that require a sequentially spotlighting process. For such tasks, the linear separability effect of a visual feature distribution should be considered. Hence, we introduce this effect to spatially localized activation. Concretely, our top-down model estimates target-specific visual attention using Fisher's variance ratio between a visual feature distribution of a local region in the field of view and that of a target stimulus. We confirm the effectiveness of our computational model through a visual search experiment.

In this paper, we investigate the fault-tolerant Hamiltonian problems of crossed cubes with a faulty path. More precisely, let P denote any path in an n-dimensional crossed cube CQn for n ≥ 5, and let V(P) be the vertex set of P. We show that CQn-V(P) is Hamiltonian if |V(P)|≤n and is Hamiltonian connected if |V(P)| ≤ n-1. Compared with the previous results showing that the crossed cube is (n-2)-fault-tolerant Hamiltonian and (n-3)-fault-tolerant Hamiltonian connected for arbitrary faults, the contribution of this paper indicates that the crossed cube can tolerate more faulty vertices if these vertices happen to form some specific types of structures.

To analyze the structure of a set of high-dimensional perfect sequences over a composition algebra over R, we developed the theory of Fourier transforms of the set of such sequences. We define the discrete cosine transform and the discrete sine transform, and we show that there exists a relationship between these transforms and a convolution of sequences. By applying this property to a set of perfect sequences, we obtain a parameterization theorem. Using this theorem, we show the equivalence between the left perfectness and right perfectness of sequences. For sequences of real numbers, we obtain the parameterization without restrictions on the parameters.

This report describes an all-digital phase-locked loop (ADPLL) using a temperature compensated settling time reduction technique. The novelty of this work is autonomous oscillation control word estimation without a look-up table or memory circuits. The proposed ADPLL employs a multi-phase digitally controlled oscillator (DCO). In the proposed estimation method, the optimum oscillator tuning word (OTW) is estimated from the DCO frequency characteristic in the setup phase of ADPLL. The proposed ADPLL, which occupies 0.27×0.36mm2, is fabricated by a 65 nm CMOS process. The temperature compensation PLL controller (TCPC) is implemented using an FPGA. Although the proposed method has 20% area overhead, measurement results show that the 47% settling time is reduced. The average settling time at 25°C is 3µs. The average reduction energy is at least 42% from 0°C to 100°C.

The primitive called public key encryption with non-interactive opening (PKENO) is a class of public key encryption (PKE) with additional functionality. By using this, a receiver of a ciphertext can prove that the ciphertext is an encryption of a specified message in a publicly verifiable manner. In some situation that a receiver needs to claim that a ciphertext is NOT decrypted to a specified message, if he/she proves the fact by using PKENO straightforwardly, the real message of the ciphertext is revealed and a verifier checks that it is different from the specified message about which the receiver wants to prove. However, this naive solution is problematic in terms of privacy. Inspired by this problem, we propose the notion of disavowable public key encryption with non-interactive opening (disavowable PKENO) where, with respect to a ciphertext and a message, the receiver of the ciphertext can issue a proof that the plaintext of the ciphertext is NOT the message. Also, we give a concrete construction. Specifically, a disavowal proof in our scheme consists of 61 group elements. The proposed disavowable PKENO scheme is provably secure in the standard model under the decisional linear assumption and strong unforgeability of the underlying one-time signature scheme.

This paper focuses on the power of comments to predict fault-prone programs. In general, comments along with executable statements enhance the understandability of programs. However, comments may also be used to mask the lack of readability in the program, therefore well-written comments are referred to as “deodorant to mask code smells” in the field of code refactoring. This paper conducts an empirical analysis to examine whether Lines of Comments (LCM) written inside a method's body is a noteworthy metric for analyzing fault-proneness in Java methods. The empirical results show the following two findings: (1) more-commented methods (the methods having more comments than the amount estimated by size and complexity of the methods) are about 1.6 - 2.8 times more likely to be faulty than the others, and (2) LCM can be a useful factor in fault-prone method prediction models along with the method size and the method complexity.

ThruChip interface (TCI) is an emerging wireless interface in three-dimensional (3-D) integrated circuit (IC) technology. However, the TCI physical design guidelines remain unclear. In this paper, a ThruChip test chip is designed and fabricated for design guidelines exploration. Three inductive coupling interface physical design scenarios, baseline, power mesh, and dummy metal fill, are deployed in the test chip. In the baseline scenario, the test chip measurement results show that thinning chip or enlarging coil dimension can further reduce TCI power. The power mesh scenario shows that the eddy current on power mesh can dramatically reduce magnetic pulse signal and thus possibly cause TCI to fail. A power mesh splitting method is proposed to effectively suppress eddy current impact while minimizing power mesh structure impact. The simulation results show that the proposed method can recover 77% coupling coefficient loss while only introducing additional 0.5% IR-drop. In dummy metal fill case, dummy metal fill enclosed within TCI coils have no impact on TCI transmission and thus are ignorable.