Stochastic computing (SC), which is an approximate computation with probabilities, has attracted attention owing to its small area, small power consumption and high fault tolerance. In this paper, we focus on the transient fault tolerance of SC based on linear finite state machines (linear FSMs). We show that state assignment of FSMs considerably affects the fault tolerance of linear FSM-based SC circuits, and present a Markov model for representing the impact of the state assignment on the behavior of faulty FSMs and estimating the expected error significance of the faulty FSM-based SC circuits. Furthermore, we propose a heuristic algorithm for appropriate state assignment that can mitigate the influence of transient faults. Experimental analysis shows that the state assignment has an impact on the transient fault tolerance of linear FSM-based SC circuits and the proposed state assignment algorithm can achieve a quasi-optimal state assignment in terms of high fault tolerance.

The objective of this letter is to present a family of q-ary codes with parameters $[rac{q^m-1}{q-1},rac{q^m-1}{q-1}-2m,d]$, where m is a positive integer, q is a power of an odd prime and 4≤d≤5. The parameters are proved to be optimal or almost optimal with respect to an upper bound on linear codes.

In the theory of orthogonal arrays, an orthogonal array (OA) is called schematic if its rows form an association scheme with respect to Hamming distances. In this paper, we study the Hamming distances of any two rows in an OA, construct some schematic OAs of strength two and give the positive solution to the open problem for classifying all schematic OAs. Some examples are given to illustrate our methods.

To construct good DNA codes based on biologically motivated constraints, it is important that they have a large minimum Hamming distance and the number of GC-content is kept constant. Also, maximizing the number of codewords in a DNA code is required for given code length, minimum Hamming distance, and number of GC-content. In most previous works on the construction of DNA codes, quaternary constant weight codes were directly used because the alphabet of DNA strands is quaternary. In this paper, we propose new coding theoretic constructions of DNA codes based on the binary Hadamard matrix from a binary sequence with ideal autocorrelation. The proposed DNA codes have a greater number of codewords than or the equal number to existing DNA codes constructed from quaternary constant weight codes. In addition, it is numerically shown that for the case of codes with length 8 or 16, the number of codewords in the proposed DNA code sets is the largest with respect to the minimum reverse complementary Hamming distances, compared to all previously known results.

In this letter, we integrate domain information into the original artificial bee colony algorithm to create a novel, neighbor-interactive bee colony algorithm. We use the Hamming distance measure to compute variable dependency between two binary variables and employ the Gini correlation coefficient to compute variable relation between integer variables. The proposed optimization method was evaluated by minimizing binary Ising models, integer Potts models, and trapped functions. Experimental results show that the proposed method outperformed the traditional artificial bee colony and other meta-heuristics in all the testing cases.

Cyclic codes are a subclass of linear codes and have applications in consumer electronics, data storage systems, and communication systems as they have efficient encoding and decoding algorithms compared with the linear block codes. The objective of this letter is to present a family of p-ary cyclic codes with length $rac{p^m-1}{p-1}$ and dimension $rac{p^m-1}{p-1}-2m$, where p is an arbitrary odd prime and m is a positive integer with gcd(p-1,m)=1. The minimal distance d of the proposed cyclic codes are shown to be 4≤d≤5 which is at least almost optimal with respect to some upper bounds on the linear code.

We consider the problem of sparse signal recovery from 1-bit measurements. Due to the noise present in the acquisition and transmission process, some quantized bits may be flipped to their opposite states. These sign flips may result in severe performance degradation. In this study, a novel algorithm, termed HISTORY, is proposed. It consists of Hamming support detection and coefficients recovery. The HISTORY algorithm has high recovery accuracy and is robust to strong measurement noise. Numerical results are provided to demonstrate the effectiveness and superiority of the proposed algorithm.

This paper proposes a circular bit-vector-mismatches (CBVM) algorithm for approximate circular string matching with k-mismatches. We develop the proposed CBVM algorithm based on the rotation feature of the circular pattern. By reusing the matching information of the previous substring, the next substring of the input string can be processed in parallel.

Given an odd prime q and an integer m ≤ q, an array-based parity-check matrix H(m,q) can be constructed for a quasi-cyclic low-density parity-check (LDPC) code C(m,q). For m=4 and q ≥ 11, we prove the stopping distance of H(4,q) is 10, which is equal to the minimum Hamming distance of the associated code C(4,q). In addition, a tighter lower bound on the stopping distance of H(m,q) is also given for m > 4 and q ≥ 11.

Quasi-cyclic (QC) low-density parity-check (LDPC) codes have several appealing properties regarding decoding, storage requirements and encoding aspects. In this paper, we focus on the QC LDPC codes over GF(q) whose parity-check matrices have fixed column weight j = 2. By investigating two subgraphs in the Tanner graphs of the corresponding base matrices, we derive two upper bounds on the minimum Hamming distance for this class of codes. In addition, a method is proposed to construct QC LDPC codes over GF(q), which have good Hamming distance distributions. Simulations show that our designed codes have good performance.

The fact that the stream cipher RC4 can generate colliding key pairs with hamming distance one was first discovered by Matsui in FSE 2010. This kind of weakness demonstrates that two different secret keys have the same effect on the cipher's encryption and the corresponding decryption procedure. In this paper, we further investigate the property of RC4 key collisions and achieved the following results: 1. We show that RC4 can generate colliding key pairs with various hamming distances, which cannot be generated by Matsui's pattern. We also give concrete examples of colliding key pairs with hamming distances greater than one. 2. We formalize RC4 colliding key pairs into two large patterns, namely, Transitional pattern and Self-Absorbing pattern. All the currently known colliding key pairs can be categorized into either two patterns. 3. We analyze both patterns and clarified the relations among the probability of key collision, key length and hamming distances which yield the colliding key pairs. 4. We demonstrate the vulnerability of key collisions by showing collisions of RC4-Hash function proposed in INDOCRYPT 2006. Some concrete experimental results of RC4-Hash collision are also given in this paper.

A novel self-synchronizable decoding algorithm for transmissions with redundant information is proposed. We assume that desynchronization occurs because a continuous deletion of bits in the channel. The decoder bases its decision on a metric which involves the syndrome and the Hamming distance between certain codeword and its corresponding updated codeword after one iteration of sum-product decoding. The foundation of the previous assumption relies on what we called "CP-distance." The larger the CP-distance of a code the better the synchronization characteristics. Moreover, our proposal is not restricted to cyclically permutable (CP) codes as previous proposals. Theoretical foundation and experimental results show good performance of our algorithm.

Correlation power analysis (CPA) is a well-known attack against cryptographic modules with which an attacker evaluates the correlation between the power consumption and the sensitive data candidates calculated from a guessed sub-key and known data such as plaintexts and ciphertexts. This paper enhances CPA to propose a new general power analysis, built-in determined sub-key CPA (BS-CPA), which finds a new sub-key by using the previously determined sub-keys recursively to compute the sensitive data candidates and to increase the signal-to-noise ratio in its analysis. BS-CPA also reuses the power traces in the repetitions of finding sub-keys to decrease the total number of the required traces for determining the all sub-keys. BS-CPA is powerful and effective when the multiple sensitive data blocks such as sbox outputs are processed simultaneously as in the hardware implementation. We apply BS-CPA to the power traces provided at the DPA contest and succeed in finding a DES key using fewer traces than the original CPA does.

In this paper, we improve the classification performance of categorical data using an Adoptive Hamming Distance. We defined the equivalent categorical values and showed how those categorical values were searched to adopt the distance. The effectiveness of the proposed method was demonstrated using various classification examples.

Based on cyclic difference sets, sequences with two-valued autocorrelation can be constructed. Using these constructed sequences, two classes of binary constant weight codes are presented. Some codes proposed in this paper are proven to be optimal.

In this paper, we present a hierarchical multi-chip architecture which employs fully digital and word-parallel associative memories based on Hamming distance. High capacity scalability is critically important for associative memories since the required database capacity depends on the various applications. A multi-chip structure is most efficient for the capacity scalability as well as the standard memories, however, it is difficult for the conventional nearest-match associative memories. The present digital implementation is capable of detecting all the template data in order of the exact Hamming distance. Therefore, a hierarchical multi-chip structure is simply realized by using extra register buffers and an inter-chip pipelined priority decision circuit hierarchically embedded in multiple chips. It achieves fully chip- and word-parallel Hamming distance search with no throughput decrease, additional clock latency of O(log P), and inter-chip wires of O(P) in a P-chip structure. The feasibility of the architecture and circuit implementation has been demonstrated by post-layout simulations. The performance has been also estimated based on measurement results of a single-chip implementation.

Many researchers have used hypercube interconnection networks for their good properties to construct many parallel processing systems. However, as the number of processors increases, the probability of occurrences of faulty nodes also increases. Hence, for hypercube interconnection networks which have faulty nodes, several efficient dynamic routing algorithms have been proposed which allow each node to hold status information of its neighbor nodes. In this paper, we propose an improved version of the algorithm proposed by Chiu and Wu by introducing the notion of full reachability. A fully reachable node is a node that can reach all nonfaulty nodes which have Hamming distance l from the node via paths of length l. In addition, we further improve the algorithm by classifying the possibilities of detours with respect to each Hamming distance between current and target nodes. We propose an initialization procedure which makes use of an equivalent condition to perform this classification efficiently. Moreover, we conduct a simulation to measure the improvement ratio and to compare our algorithms with others. The simulation results show that the algorithms are effective when they are applied to low-dimensional hypercube interconnection networks.

A new UEP technique for image transmission using trellis code based on Hamming distance criterion has been proposed. The simulation results comparing the image quality and bit-rate for UEP and EEP have been provided. The results show that UEP performs better than EEP in terms of bit-rate without any significant depreciation in image quality.

Error locating codes were first presented in 1963 by J.K. Wolf and B.Elspas. Since then several code design methods have been proposed. However, their algebraic structure has not yet been clarified. It is apparent that necessary and sufficient conditions for error correcting/detecting codes can be expressed by Hamming distance, but, on the other hand, those for error locating codes cannot always be expressed only by Hamming distance. This paper presents necessary and sufficient conditions for error locating codes by using a newly defined metric and a function. The function represents the number of bytes where Hamming distance between corresponding bytes of two codewords has a certain integer range. These conditions show that an error locating code having special code parameters is an error correcting/detecting code. This concludes that error locating codes include existing bit/byte error correcting/detecting codes in their special cases.