In electronic warfare support systems, the analysis of PRI (Pulse Repetition Interval) modulation characteristics for a radar pulse signal has attracted much interest because of the problem of the identification ambiguity in dense electronic warfare signal environments. A new method of recognizing the PRI modulation type of a radar pulse signal is proposed for electronic warfare support. The proposed method recognizes the PRI modulation types using classifiers based on the property of the autocorrelation of the PRI sequences for each PRI modulation type. In addition, the proposed method estimates the PRI modulation period for the PRI modulation type with the periodicity. Simulation results are presented to show the performance of the proposed method.

We experimentally investigated terahertz photomixing operation at room temperature in an InGaP/InGaAs/ GaAs two-dimensional plasmon-resonant photomixer incorporating grating-bicoupled dual-gate structure. Photoelectrons drifting into a high-density plasmon cavity grating from an adjacent low-density one extensively excite the plasmon resonance, resulting in emission of terahertz radiation. A vertical cavity formed between the two-dimensional plasmon grating plane and an indium-tin-oxide mirror at the back surface gains the radiation. Self-oscillation initially at around 4.5 THz excited by a dc-photo carrier component was reinforced by the photomixed differential-frequency excitation at 4.0 and 5.0 THz. This indicates a possibility of injection-locked oscillation of the photomixer in the terahertz frequency band.

A single-electron turnstile and electrometer circuit was fabricated on a silicon-on-insulator substrate. The turnstile, which is operated by opening and closing two metal-oxide-semiconductor field-effect transistors (MOSFETs) alternately, allows current quantization at 20 K due to single-electron transfer. Another MOSFET is placed at the drain side of the turnstile to form an electron storage island. Therefore, one-by-one electron entrance into the storage island from the turnstile can be detected as an abrupt change in the current of the electrometer, which is placed near the storage island and electrically coupled to it. The correspondence between the quantized current and the single-electron counting was confirmed.

Although a great deal of research has been done on electronic cash schemes with blind multisignatures to prevent an insider attack, there is no discussion of a formal security model in the literature. Firstly we discussed the security model of e-cash schemes based on the blind multisignature scheme against a (restricted) attack model and proposed a concrete scheme proven to be secure in the model [1]; however, this attack model disallows an attacker from corrupting an issuing bank and shops in the forgery game. In this paper, first, we reconsider the security model to remove the restriction of the attack model. Second, we propose a new untraceable e-cash scheme with a blind multisignature scheme and prove that the proposed scheme is secure against the (non-restricted) attacks under the DDH assumption in the random oracle model.

The uni-traveling-carrier photodiode (UTC-PD) is an innovative PD that has a unique operation mode in which only electrons act as the active carriers, resulting in ultrafast response and high electrical output power at the same time. This paper describes the features of the UTC-PD and its excellent performance. In addition, UTC-PD-based optoelectronic devices integrated with various elements, such as passive and active devices, are presented. These devices are promising for various applications, such as millimeter- and submillimeter-wave generation up to the terahertz range and ultrafast optical signal processing at data rates of up to 320 Gbit/s.

We examined a Ti-diffused optical waveguide formed on a thin X-cut LiNbO3 substrate for a lower-drive-voltage modulator. Under the single-mode condition, optical mode-size decreases with LiNbO3 substrate thickness below 10 µm. A thin-sheet LiNbO3 modulator could achieve a low-drive-voltage of 1.3 V with a bandwidth of 15 GHz by adopting a narrow electrode-gap.

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.

An electron transfer mediated amperometric enzyme biosensor based on a plasma-polymerized thin film of dimethylaminomethylferrocene (DMAMFc) is reported. A nanoscale thin polymer film containing a redox mediator was plasma-deposited directly onto an electrode with physisorbed glucose oxidase (GOD). Since the redox sites were introduced in the vicinity of the reaction centers of GOD, a highly efficient electron transfer system was formed in which almost all the reaction centers of GOD were connected to redox sites of the polymer matrix. The advantages of this strategy were: no need for prior or further chemical modification of the enzyme molecules, and simplicity of design compared with the use of a conventional polymer matrix. Moreover, the fact that the film deposition was performed using a microfabrication-compatible organic plasma promised great potential for high-throughput production of bioelectronic devices.

We propose a shot reduction technique of character projection (CP) Electron Beam Direct Writing (EBDW) using combined cell stencil (CCS) or the advanced process technology. CP EBDW is expected both to reduce mask costs and to realize quick turn around time. One of major issue of the conventional CP EBDW, however, is a throughput of lithography. The throughput is determined by numbers of shots, which are proportional to numbers of cell instances in LSIs. The conventional shot reduction techniques focus on optimization of cell stencil extraction, without any modifications on designed LSI mask patterns. The proposed technique employs the proposed combined cell stencil, with proposed modified design flow, for further shot reduction. We demonstrate 22.4% shot reduction within 4.3% area increase for a microprocessor and 28.6% shot reduction for IWLS benchmarks compared with the conventional technique.

This paper outlines the method of constructing single-electron logic circuits based on the binary decision diagram (BDD), a graphical representation of digital functions. The circuit consists of many unit devices, BDD devices, cascaded to build the tree of a BDD graph. Each BDD device corresponds to a node of the BDD graph and operates as a two-way switch for the transport of a single electron. Any combinatorial logic can be implemented using BDD circuits. Several subsystems for a single-electron processor have been constructed using semiconductor nano-process technology.

The feasibility of a new transistor structure was demonstrated through an experimental observation of current gain and voltage gain. The proposed transistor structure is a hot electron transistor without a base layer to minimize scattering. Electron emission from the emitter is controlled using positively biased Schottky gate electrodes located on both sides of the emitter mesa. Monte Carlo simulation shows an estimated delay time of 0.17 ps and low gate leakage current with open-circuit voltage gain over unity. To confirm the basic operation, the device with a 25 nm wide emitter was fabricated. To obtain saturated current-voltage characteristics, the emitter was surrounded by gates and parasitic regions were eliminated by electron beam lithography. The observed open-circuit voltage gain was 25. To obtain a low leakage current, an electron energy smaller than the Γ-L separation was necessary to maintain the ballistic nature of the electron. When the gate-emitter voltage was 0.8 V, the gate leakage current was only 4% of the collector current. Thus voltage amplication and current amplification were confirmed simultaneously.

Accumulation of non-equilibrium longitudinal optical (LO) phonons (termed hot phonons) is considered as a possible cause for limitation of frequency of operation of GaN-based high-electron-mobility transistors (HEMTs). The experimental data on noise temperature of hot electrons at a microwave frequency as a function of supplied electric power is used to extract information on hot phonons: the hot-phonon lifetime, the equivalent hot-phonon temperature, the effective occupancy of hot-phonon states involved into electron-LO-phonon interaction. The possible ways for controlling the hot-phonon effect on electron drift velocity through variation of electron density, channel composition, and hot-phonon lifetime are discussed. The expected dependence of hot-electron drift velocity on hot-phonon lifetime is confirmed experimentally. A self-consistent explanation of different frequency behaviour of InP-based and GaN-based HEMTs is obtained from a comparative study of hot-phonon effects.

We study the coupled spatio-temporal variations of the electron density and the electric field (electron plasma oscillations) in high-electron mobility transistors using the developed device model. The excitation of electron plasma oscillations in the terahertz range of frequencies might lead to the emission of terahertz radiation. In the framework of the model developed, we calculate the resonant plasma frequencies and find the conditions for the plasma oscillations self-excitation (plasma instability) We show that the transit-time effect in the high-electric field region near the drain edge of the channel of high-electron mobility transistors can cause the self-excitation of the plasma oscillations. It is shown that the self-excitation of plasma oscillations is possible when the ratio of the electron velocity in the high field region, ud, and the gate length, Lg, i.e., the inverse transit time are sufficiently large in comparison with the electron collision frequency in the gated channel, ν. The transit-time mechanism of plasma instability under consideration can superimpose on the Dyakonov-Shur mechanism predicted previously strongly affecting the conditions of the instability and, hence, terahertz emission. The instability mechanism under consideration might shed light on the origin of terahertz emission from high electron mobility transistors observed in recent experiments.

In this paper, a new dimming algorithm for the electronic ballast of an electrodeless fluorescent lamp is proposed. The proposed method is based on the burst dimming method that controls the duty ratio for the two switches of the electronic ballast by intermittently modulated pulse signal. This paper presents a fully digital circuit using an erasable programmable logic device (EPLD). To verify the validity of the proposed method, the implemented control circuit was applied to the electronic ballast for a 100 W electrodeless fluorescent lamp. As a result, a dimming method with a wide illumination range from 5 to 100% was obtained.

HfOxNy thin films formed by the electron cyclotron resonance (ECR) Ar/N2 plasma nitridation of HfO2 films were investigated for high-k gate insulator applications. HfOxNy thin films formed by the ECR Ar/N2 plasma nitridation (60 s) of 1.5-nm-thick HfO2 films, which were deposited on chemically oxidized Si(100) substrates, were found to be effective for suppressing interfacial layer growth or crystallization during postdeposition annealing (PDA) in N2 ambient. After 900 PDA of for 5 min in N2 ambient, it was found that HfSiON film with a relatively high dielectric constant was formed on the HfOxNy/Si interface by Si diffusion. An equivalent oxide thickness (EOT) of 2.0 nm and a leakage current density of 1.010-3 A/cm2 (at VFB-1 V) were obtained. The effective mobility of the fabricated p-channel metal-insulator-semiconductor field-effect transistor (MISFET) with the HfOxNy gate insulator was 50 cm2/Vs, and the gate leakage current of the MISFET with the HfOxNy gate insulator was found to be well suppressed compared with the MISFET with the HfO2 gate insulator after 900 PDA because of the nitridation of HfO2.

We propose a cell library development methodology for throughput enhancement of character projection equipment. First, an ILP (Integer Linear Programming)-based cell selection is proposed for the equipment for which both of the CP (Character Projection) and VSB (Variable Shaped Beam) methods are available, in order to minimize the number of electron beam (EB) shots, that is, time to fabricate chips. Secondly, the influence of cell directions on area and delay time of chips is examined. The examination helps to reduce the number of EB shots with a little deterioration of area and delay time because unnecessary directions of cells can be removed. Finally, a case study is shown in which the numbers of EB shots are shown for several cases.

In this paper, routing properties of cube-based optoelectronic OTIS networks are explored. We show emulations of various cubical network topologies on their OTIS augmented variants, including the n-D grid networks, shuffle-exchange, and de Brujin networks. An analytical performance model for OTIS-cube networks is proposed. The model is validated by means of comparison with rigorously obtained simulation results. Using this model, the performance characteristics of the OTIS-hypercube network are evaluated in view of a number of different constraints. Moreover, we compare the performance characteristics of the OTIS-hypercube with that of equivalent fully-electronic networks under various implementation constraints.

Contract signing is a practical application of the fair exchange of digital signatures. This application used to be realized by directly adopting the results of the fair exchange of signatures, which do not completely meet the requirements of the signing of a secret contract. The assistance of a trusted third party (TTP) and some cryptographic technology are required to allow two parties to exchange their signatures through the network in a fair manner because these two parties potentially may be dishonest or mistrust each other. This paper presents a subtle method of preventing the off-line TTP from gaining the exchanged signature and the corresponding message when a dispute occurs between the two parties wherein the TTP is required to take part in the exchange procedure. An advanced concept, the non-disclosure property, is proposed in order to prevent a party from misusing evidence left during the exchange process. Two approaches, namely the secret divide method and the convertible signature are demonstrated. To satisfy the properties of the traditional paper-based contract signing, the technique of multi-signature scheme is used in the proposed protocols.

When a large-size car exists on the ETC lane (Electronic Toll Collection System), there is the possibility that the interference on the adjacent lane occurs by the scattering waves from one. In this paper, we propose a new improvement method which the transparent EM wave absorber is placed between the ETC lane and the adjacent one in order to suppress the scattering waves from a large-size car. Therefore, we design the transparent EM wave absorber which consists of the transparent resistive and conductive films. Then, this absorber is produced, and its reflection and transmission coefficients are evaluated. In addition, its transmittance in optics is evaluated. As the results, the reflectivity of this absorber is obtained lower than -20 dB in the oblique incident angle from 0to 30at 5.8 GHz circular polarized wave, abbreviated as CP wave, and also the transmittivity is obtain lower than -27 dB in the oblique incident angle from 0to 70, respectively. On the other hand, the transmittance in optics is obtained higher than 60%. Moreover, we study experimentally on the ETC system with placing this absorber between the ETC lane and the adjacent one. We measured the distribution of receiving power on the adjacent lane, when a water sprinkler existed on the ETC lane. As a result, it is confirmed that the receiving power on the adjacent lane could be realized lower than -70.5 dBm, and then a new improvement method has proven to be very useful in the ETC system.

A fully Internet-connected business environment is subject to frequent changes. To ordinary customers, online shopping under such a dynamic environment can be frustrating. We propose a new E-commerce service called the CIGMA to assist online customers under such an environment. The CIGMA provides catalog comparison and purchase mediation services over multiple shopping sites for ordinary online customers. The service is based on up-to-date information by reflecting the frequent changes in catalog information instantaneously. It also matches the desire of online customers for fast response. This paper describes the CIGMA along with its architecture and the implementation of a working prototype.