As pseudorandom number generators for Monte Carlo simulations, inversive linear congruential generators (ICG) have some advantages compared with traditional linear congruential generators. It has been shown that a sequence generated by an ICG has a low discrepancy even if the length of the sequence is far shorter than its period. In this paper, we formulate fractional linear congruential generators (FCG), a generalized concept of the inversive linear congruential generators. It is shown that the sequence generated by an FCG is a geometrical shift of a sequence from an ICG and satisfies the same upper bounds of discrepancy. As an application of the general formulation, we show that under certain condition, "Leap-Frog technique," a way of splitting a random number sequence to parallel sequences, can be applied to the ICG or FCG with no extra cost on discrepancy.

Studies of cellular automata (CA) based random number generators (RNGs) have focused mainly upon symmetrically connected networks with neighborhood sizes of three or five. Popular field programmable gate array configurations feature a four-input (i.e., 16-row) lookup table. Full utilization of the four-input lookup table leads to the potential for asymmetrically connected cellular automata networks with a neighborhood size of four. From each of various 1-d, 2-d, and 3-d networks with periodic boundary conditions, the 1000 highest entropy CA RNGs were selected from the set of 65,536 possible uniform (all CA truth tables the same) implementations. Each set of 1000 high-entropy CA was then submitted to Marsaglia's DIEHARD suite of random number tests. A number of 64-bit, neighbor-of-four CA-based RNGs have been discovered that pass all tests in DIEHARD without resorting to either site spacing or time spacing to improve the RNG quality.

We have recently developed a programmable composite noise generator (P-CNG) which can easily control noise parameters such as average power, time-based amplitude probability distribution (APD), crossing rate distribution, occurrence frequency distribution and burst duration. Two applications of the P-CNG are demonstrated to show its usefulness. For the first application, Middleton's Class A noise is simulated. A method of setting parameters for Class A noise is demonstrated. The APD of P-CNG output is in good agreement with that of true Class A noise. In the second application, the P-CNG is used for subjective evaluation test (opinion test) of TV picture degradation. Five simple composite noise models with two kinds of APD are used. Other parameters such as average power are kept constant. Experimental results show that the envelope and APD of composite noises do not greatly influence the subjective evaluation. Finally the capabilities of the P-CNG are shown.

This paper presents a new deterministic built-in test scheme using a neighborhood pattern generator (NPG) to guarantee complete fault efficiency with small test-data storage. The NPG as a decoding logic generates both a parent pattern and deterministic child patterns within a small Hamming distance from the parent pattern. A set of test cubes is encoded as a set of seeds for the NPG. The proposed method is practically acceptable because no impact on a circuit under test is required and the design of the NPG does not require the results of test generation. We also describe an efficient seed generation method for the NPG. Experimental results for benchmark circuits demonstrate that the proposed method can significantly reduce the storage requirements when compared with other deterministic built-in test methods.

A charge pump circuit suitable for positive high voltage generators at sub-1.5 V range is presented. The proposed heap-pump circuit provides a high voltage generator having not only high pumping efficiency by eliminating threshold voltage drop but also simplest single phase clock scheme.

It is shown that the effective secret-key size of TOYOCRYPT-HS1 stream cipher is only 96 bits, although the secret key consists of 128 bits. This characteristic opens a door for developing an algorithm for cryptanalysis based on the time-memory-data trade-off with the overall complexity significantly smaller than the exhaustive search over the effective key space.

In this paper, important methods for cryptanalysis of the stream cipher based on a class of keystream generators are discussed. These methods employ an approach called the fast correlation attack. This cryptographic problem is treated by considering its equivalent channel coding approach, namely decoding of certain very low rate codes in presence of very high noise. A novel family of algorithms for the fast correlation attack is presented. The algorithms are based on the iterative decoding principle in conjunction with a novel method for constructing the parity-checks. A goal of this paper is to summarize reported results and to compare some of the recent ones. Accordingly, the family is compared with recently proposed improved fast correlation attacks based on iterative decoding methods. An analysis of the algorithms performances and complexities is presented. The corresponding trade-offs between performance, complexity and required inputs are pointed out.

In this report, a design method of neural networks for limit cycle generator is described. First, the constraint conditions for the synaptic weights, which are given by the linear inequalities, are derived from the dynamics of neural networks. Next, the linear inequalities are solved by the linear programming method. The synaptic weights and other parameters are determined by the above solutions. Furthermore, neuro-based limit cycle generator is designed with analog electronic circuits and simulated by Spice. Finally, we confirm that our design method is efficient and practical for the design of neuro-based limit cycle generator.

An algorithm for cryptanalysis of certain keystream generators is proposed. The developed algorithm has the following two advantages over other reported ones: it is more powerful, and it can be implemented by a high-speed software or a simple hardware suitable for high parallel architectures. The algorithm is based on error-correction of information bits only (of the corresponding binary block code) with a novel method for construction of the parity-checks, and the employed error-correction procedure is an APP based threshold decoding. Experimental and theoretical analyses of the algorithm performance are presented, and its complexity is evaluated. The proposed algorithm is compared with recently proposed improved fast correlation attacks based on convolutional codes and turbo decoding. The underlying principles, performance and complexity are compared, and the gain obtained with the novel approach is pointed out.

To make clear numerically the scattering characteristics for a body embedded in a random medium, we need to analyze the bistatic cross-section (BCS). The scattering problem can be analyzed as a boundary value problem by using current generator method. The fourth moment of Green's functions in the random medium, which is necessary for the analysis, is obtained approximately by two-scale method. We analyze numerically the BCS of conducting circular cylinders in continuous random media, which are assumed to fluctuate about the dielectric constant of free space. The numerical results agree well with the law of energy conservation. The effects of random media on the BCS are also clarified numerically.

New positive and negative bias voltage generators for TFT-LCD's drivers utilizing charge pump circuits are introduced. The generators can generate positive or negative voltages with various amplitude by simply changing the number of pumping stages. By using the circuit simulation program HSPICE, it is demonstrated that the introduced generators can provide enough positive or negative voltages for TFT-LCD's drivers.

In this paper, a program generator for communication protocol software will be presented. Our program generator takes an extended finite state machine as a domain model and generates a group of C++ classes needed for an implementation. For each state of the FSM, a C++ class is generated, where the interface events are implemented as member functions of the corresponding state object. Protocol data units (PDUs) are embedded as Message objects and specified in the same way as packet filter and is interpreted to generate necessary PDU definition statements and PDU manipulation statements. Also, protocol objects from different layers can be linked together by using an organization model, where a protocol entity is invoked by its upper layer entity or lower layer entity by member function calls.

There are many public key cryptosystems that require random inputs to encrypt messages and their security is always discussed assuming that random objects are ideally generated. Since cryptosystems run on computers, it is quite natural that these random objects are computationally generated. One theoretical solution is the use of pseudorandom generators in the Yao's sense. Informally saying, the pseudorandom generators are polynomial-time algorithms whose outputs are computationally indistinguishable from the uniform distribution. Since if we use the Yao's generators then it takes much more time to generate pseudorandom objects than to encrypt messages in public key cryptosystems, we relax the conditions of pseudorandom generators to fit public key cryptosystems and give a minimal requirement for pseudorandom generators within public key cryptosystems. As an example, we discuss the security of the ElGamal cryptosystem with some well-known generators (e. g. , the linear congruential generator). We also propose a new pseudorandom number generator, for random inputs to the ElGamal cryptosystem, that satisfies the minimal requirement. The newly proposed generator is based on the linear congruential generator. We show some evidence that the ElGamal cryptosystem with the proposed generator is secure.

A two-phase boosted voltage (VPP) generator circuit was proposed for use in giga-bit DRAMs. It reduced the maximum gate oxide voltage of pass transistor and the lower limit of supply voltage to VPP and VTN respectively while those for the conventional charge pump circuit are VPP+VDD and 1.5 VTN respectively. Also the pumping current was increased in the new circuit.

This paper proposes a realization of power factor function generator having an arbitrary base and power factor which are determined by the ratios of the currents provided from outside of the circuit. The circuit characteristics do not depend on any transistor parameters, temperature, and other environmental conditions. The circuit operation is based on current mode that has a capability of low power supply voltage operation below than 2.0 V. SPICE simulation has been carried out using 0.7 µm BiCMOS parameters and shows quite good transfer characteristics.

In order to guarantee pairwise independence of codewords in an ensemble of convolutional codes it is necessary to consider time-varying codes. However, Seguin has shown that the pairwise independence property is not strictly necessary when applying the random coding argument and on this basis he derives a new random coding bound for rate 1/n fixed convolutional codes. In this paper we show that a similar random coding bound can be obtained for rate k/n fixed convolutional codes.

This paper presents the generator polynomial matrices and the upper bound on the constraint length of punctured convolutional codes (PCCs), respectively. By virtue of these properties, we provide the puncturing realizations of the good known nonsystematic and systematic high rate CCs.

This paper treats the systematic design of chaos generators which are capable of generating continuous-time signals with prescribed probability density function and power density spectra. For a specific signal model a statistical analysis is performed such that the inverse problem, i. e. the calculation of the model parameters from prescribed signal characteristics, can be solved. Finally from the obtained model parameters and the model structure the signal generating system is constructed. The approach is illustrated by several examples.

We have proposed and demonstrated a novel optical regenerator architecture employing electroabsorption modulators as wavelength converters. The employment of EA modulators is advantageous for high-speed operation and flexibility in the bit-rate for the pulse regeneration. In addition, the EA modulator-wavelength-converter acts also as a photo diode for clock extraction. Compensation of the optical SNR and Q-factor has been demonstrated, even in cascaded noise load. Furthermore, against dispersion loading, we have confirmed that waveform recovery and Q-factor improvement is obtained by midway insertion of the optical regenerator. The proposed architecture will offer a wide-band-electronics-free optical regenerator in multi-tens of gigabit per second WDM networks.

We have proposed and demonstrated a novel optical regenerator architecture employing electroabsorption modulators as wavelength converters. The employment of EA modulators is advantageous for high-speed operation and flexibility in the bit-rate for the pulse regeneration. In addition, the EA modulator-wavelength-converter acts also as a photo diode for clock extraction. Compensation of the optical SNR and Q-factor has been demonstrated, even in cascaded noise load. Furthermore, against dispersion loading, we have confirmed that waveform recovery and Q-factor improvement is obtained by midway insertion of the optical regenerator. The proposed architecture will offer a wide-band-electronics-free optical regenerator in multi-tens of gigabit per second WDM networks.