The ESIGN signature scheme was initially proposed in 1985. Since then, several variants have been proposed, but only a few have been formally supported using the methodology of provable security. In addition, these schemes are different from the ESIGN-PSS signature scheme submitted to ISO/IEC-14888-2 for standardization. It is believed that ESIGN-PSS is secure against the chosen-message attack, however, there has not yet been any report verifying this belief. This paper presents the security proofs of ESIGN-PSS and a variant of this scheme, denoted ESIGN-PSS-R, which is a signature scheme comprising the ESIGN signature mechanism and the PSS-R mechanism.

In the case of miniaturized telemetry capsules, such as a capsule endoscope that can acquire and transmit images from the intestines, the size and the power consumption of the module are restricted. In the capsule endoscopes, it is desirable that the control function can capacitate the sampling of digestive fluid and tissue, drug delivery, and locomotion. In this paper, the control function was embodied by bi-directional communication. A CPLD (complex programmable logic device) controller was designed and implemented for the bi-directional communication in capsule endoscope. The diameter of capsule was 12 mm and the length was 30 mm. The performance of implemented capsule was verified by in-vivo animal experiments.

An effective way to boost power gain without noise figure degradation in a cascode low noise amplifier (LNA) is demonstrated at 4 GHz using 0.35 µm SiGe HBT technology. This approach maintains the same current consumption because a low-pass π-type LC matching network is inserted in the inter-stage of a conventional cascode LNA. 5 dB gain enhancement with no noise figure degradation at 4 GHz is observed in the SiGe HBT LNA with inter-stage matching.

Simultaneous all-optical frequency up/downconversion technique utilizing a single semiconductor optical amplifier Mach-Zehnder interferometer (SOA-MZI) for full-duplex WDM radio over fiber (RoF) applications is presented. Using this technique, error-free simultaneous upconversion and downconversion of RoF signals with a finite-length single mode fiber were experimentally demonstrated. The results show the potential of the proposed scheme for use in a cost-effective full-duplex WDM RoF link.

A 5.2 GHz 1 dB conversion gain, IP1 dB = -19 dBm and IIP3= -9 dBm double quadrature Gilbert downconversion mixer with polyphase filters is demonstrated by using 0.35 µm SiGe HBT technology. The image rejection ratio is better than 47 dB when LO=5.17 GHz and IF is in the range of 15 MHz to 45 MHz. The Gilbert downconverter has four-stage RC-CR IF polyphase filters for the image rejection. Polyphase filters are also used to generate LO and RF quadrature signals around 5 GHz in the double quadrature downconverter.

In this paper, we apply iterative detection to typical time hopping (TH) pulse position modulation (PPM) ultra wideband (UWB) spread spectrum systems. Unlike a typical TH-PPM UWB which employs repetition code, the proposed system uses self-encoded code which is updated by user information itself. To take advantage of self-encoded spread spectrum, we apply iterative detection to the TH-PPM UWB system. Simulations are conducted to investigate the bit error rate (BER) performance of the proposed system in additive white gaussian noise (AWGN) channels as well as in fading and multipath channels. We observe a significant BER performance improvement over conventional TH-PPM UWB systems.

The Evolutionary Electronics refers to the design method of electronic circuits with the help of Evolutionary Algorithms. Over the years huge experience has been accumulated and tremendous results have been achieved in this field. Two obvious tendencies are prevailing in the area over designers to improve the performance of Evolutionary Algorithms. First of all, as with any solution-search-algorithm, the designers try to reduce the potential solution space in order to reach the optimum solution faster, putting some constrains onto search algorithm as well as onto potential solutions. At the same time, the second tendency of unconstraining the Evolutionary Algorithms in its search gives unpredictable breakthroughs in results. Enabling the evolution to optimize with more experimental parameters devoted to drive the evolution and adjusted previously manually, is one of an example where such kind of unconstraining takes place. The evolution with the maximum freedom of search can be addressed as unconstrained evolution. The unconstrained evolution has already been applied in the past towards the design of digital circuits, and extraordinary results have been obtained, including generation of circuits with smaller number of electronic components. Recently, the similar method has been introduced by authors of this paper towards the design of analogue circuits. The new algorithm has produced promising results in terms of quality of the circuits evolved and evolutionary resources required. It differed from constrained method by its simplicity and represented one of the first attempts to apply Evolutionary Strategy towards the analogue circuit design. In this paper both conventional constrained evolution and newly developed unconstrained evolution in analogue domain are compared in detail on the example of "LC" low-pass filter design. The unconstrained evolution demonstrates the superior behaviour over the constrained one and exceeds by quality of results the best filter evolved previously by 240%. The experimental results are presented along with detailed analysis. Also, the obtained results are compared in details with low-pass filters designed previously.

This paper considers the optimal generator matrices of a given binary cyclic code over a binary symmetric channel with crossover probability p→0 when the goal is to minimize the probability of an information bit error. A given code has many encoder realizations and the information bit error probability is a function of this realization. Our goal here is to seek the optimal realization of encoding functions by taking advantage of the structure of the codes, and to derive the probability of information bit error when possible. We derive some sufficient conditions for a binary cyclic code to have systematic optimal generator matrices under bounded distance decoding and determine many cyclic codes with such properties. We also present some binary cyclic codes whose optimal generator matrices are non-systematic under complete decoding.

This paper presents an asynchronous multiple-valued current-mode data-transfer controller chip based on a 1-phase dual-rail encoding technique. The proposed encoding technique enables "one-way delay" asynchronous data transfer because request and acknowledge signals can be transmitted simultaneously and valid states are detected by calculating the sum of dual-rail codewords. Since a key component, a current-to-voltage conversion circuit in a valid-state detector, is tuned so as to obtain a sufficient voltage range to improve switching speed of a comparator, signal detection can be performed quickly in spite of using 6-level signals. It is evaluated using HSPICE simulation with a 0.18-µm CMOS that the throughput of the proposed circuit based on the 1-phase dual-rail scheme attains 435 Mbps/wire which is 2.9 times faster than that of a CMOS circuit based on a conventional 4-phase dual-rail scheme. The test chip is fabricated, and the asynchronous data-transfer behavior of the proposed scheme is confirmed.

This paper proposes a 15-bit 10-MS/s pipelined ADC based on the incomplete settling principle. The traditional complete settling stage is improved to the incomplete settling structure through dividing the sampling clock of the traditional stage into two parts for discharging the sampling and feedback capacitors and completing the sampling, respectively. The proposed ADC verifies the correction and validity of optimizing ADCs' conversion speed without additional power consumption through the incomplete settling. This ADC employs scaling-down scheme to achieve low power dissipation and utilizes full-differential structure, bottom-plate-sampling, and capacitor-sharing techniques as well as bit-by-bit digital self-calibration to increase the ADC's linearity. It is processed in 0.18 µm 1P6M CMOS mixed-mode technology. Simulation results show that 82 dB SNDR and 87 dB SFDR are obtained at the sampling rate of 10 MHz with the input sine frequency of 100 kHz and the whole static power dissipation is 21.94 mW.

An algorithm for encoding low-density parity check (LDPC) codes is investigated. The algorithm computes parity check symbols by solving a set of sparse equations, and the triangular factorization is employed to solve the equations efficiently. It is shown analytically and experimentally that the proposed algorithm is more efficient than the Richardson's encoding algorithm if the code has a small gap.

This paper deals with the Optimum Communication Spanning Tree Problem (OCST) which is well known as an NP-hard problem. For solving the problem, we uses an evolutionary approach. This paper presents a new effective tree encoding and proposes a tree construction routine (TCR) to generate a tree from the encoding. The basic principle is to break a cycle. We also propose a new crossover operator that focuses on the inheritance of parental information and the use of network information. Consequently, we confirm that the proposed algorithm is superior to other algorithms applied to the OCST problem or other tree problems. Moreover, our method can find a better solution than the solution which was previously known as the best solution. In addition, we analyzed the locality and diversity property of encoding and observed that the proposed method has high locality and at the same time it preserves population diversity for many generations. Finally, we conclude that these properties are the main reasons why the proposed method outperforms the other encodings.

Nonlinear modeling of complex irregular systems constitutes the essential part of many control and decision-making systems and fuzzy logic is one of the most effective algorithms to build such a nonlinear model. In this paper, a new approach to fuzzy modeling is proposed. The model considered herein is the well-known Sugeno-type fuzzy system. The fuzzy modeling algorithm suggested in this paper is composed of two phases: coarse tuning and fine tuning. In the first phase (coarse tuning), a successive clustering algorithm with the fuzzy validity measure (SCFVM) is proposed to find the number of the fuzzy rules and an initial fuzzy model. In the second phase (fine tuning), a moving genetic algorithm with partial encoding (MGAPE) is developed and used for optimized tuning of membership functions of the fuzzy model. Two computer simulation examples are provided to evaluate the performance of the proposed modeling approach and compare it with other modeling approaches.

An instance of the classical stable marriage problem requires all participants to submit a strictly ordered preference list containing all members of the opposite sex. However, considering applications in real-world, we can think of two natural relaxations, namely, incomplete preference lists and ties in the lists. Either variation leaves the problem polynomially solvable, but it is known that finding a maximum cardinality stable matching is NP-hard when both variations are allowed. It is easy to see that the size of any two stable matchings differ by at most a factor of two, and so, an approximation algorithm with a factor two is trivial. A few approximation algorithms have been proposed with approximation ratio better than two, but they are only for restricted instances, such as restricting occurrence of ties and/or lengths of ties. Up to the present, there is no known approximation algorithm with ratio better than two for general inputs. In this paper, we give the first nontrivial result for approximation of factor less than two for general instances. Our algorithm achieves the ratio for an arbitrarily positive constant c, where N denotes the number of men in an input.

In this paper, we develop a new distributed adaptive power control framework for multi-cell OFDM systems based on the game theory. A specific utility function is defined considering the users' achieved average utility per power, i.e., power unit based utility. We solve the subcarrier allocation issue naturally as well as the power control. Each user tries to maximize its utility by adjusting the transmit power on each subcarrier. A Nash equilibrium for the game is shown to exist and the numerical results show that our proposal outperforms the pure water-filling algorithm in terms of efficiency and fairness.

A baseband transmission scheme for wireless communications has been proposed and examined using a pair of discone antennas for transmission and reception. The wireless baseband transmission scheme radiates a baseband signal stream, such as non-return-to-zero (NRZ), return-to-zero (RZ), or Manchester encoded signals, directly from an antenna. Namely, a carrier in terms of a sinusoidal radio wave or light wave is not used in the transmission. In experiments, baseband pulses generated with a data generator were radiated directly from the discone antenna, and received waveforms were observed with a digital storage oscilloscope. The experiments showed that wireless baseband transmission is realisable when using antennas with a flat amplitude spectrum and a linear phase characteristic, such as discone antennas, over a given band. Manchester encoding is promising for this wireless baseband transmission.

We report a specially designed encoding technique for sign language video sequences supposing that the technique is for sign telecommunication such as that using mobile videophones with a low bitrate. The technique is composed of three methods: gradient coding, precedence macroblock coding, and not-coded coding. These methods are based on the idea to distribute a certain number of bits for each macroblock according to the evaluation of importance of parts of the picture. They were implemented on a computer and encoded data of a short clip of sign language dialogue was evaluated by deaf subjects. As a result, the efficiency of the technique was confirmed.

This paper describes the efficiency of VLSI architecture for UMHexagonS (hybrid Unsymmetrical cross Multi Hexagon grid Search) matching algorithm. This algorithm is used for ME (Motion Estimation) of H.264/AVC video compression standard. The UMHexagonS is called a hybrid algorithm since it uses different kinds of searching patterns. VLSI architecture based on UMHexagonS is designed to provide a good tradeoff between gate sizes and high throughput. We implemented this architecture with about 309 K gates and 1/1792 throughput [block/cycle] for a search range of 16 and 44 macro blocks using synthesizable Verilog HDL.

Genetic Algorithm (GA) and other Evolutionary Algorithms (EAs) have been successfully applied to solve constrained minimum spanning tree (MST) problems of the communication network design and also have been used extensively in a wide variety of communication network design problems. Choosing an appropriate representation of candidate solutions to the problem is the essential issue for applying GAs to solve real world network design problems, since the encoding and the interaction of the encoding with the crossover and mutation operators have strongly influence on the success of GAs. In this paper, we investigate a new encoding crossover and mutation operators on the performance of GAs to design of minimum spanning tree problem. Based on the performance analysis of these encoding methods in GAs, we improve predecessor-based encoding, in which initialization depends on an underlying random spanning-tree algorithm. The proposed crossover and mutation operators offer locality, heritability, and computational efficiency. We compare with the approach to others that encode candidate spanning trees via the Pr?fer number-based encoding, edge set-based encoding, and demonstrate better results on larger instances for the communication spanning tree design problems.

In order to improve the efficiency and speed of match seeking in fractal compression, this paper presents an Average-Variance function which can make the optimal choice more efficiently. Based on it, we also present a fast optimal choice fractal image compression algorithm and an optimal method of constructing data tree which greatly improve the performances of the algorithm. Analysis and experimental results proved that it can improve PSNR over 1 dB and improve the coding speed over 30-40% than ordinary optimal choice algorithms such as algorithm based on center of gravity and algorithm based on variance. It can offer much higher optimal choice efficiency, higher reconstructive quality and rapid speed. It's a fast fractal encoding algorithm with high performances.