Traveling electromagnetic waves on infinite linear periodic arrays of lossless penetrable spheres can be conveniently analyzed using the source scattering-matrix framework and vector spherical wave functions. It is assumed that either the spheres are sufficiently small, or the frequency such, that the sphere scattering can be treated using only electric and magnetic dipole vector spherical waves, the electric and magnetic dipoles being orthogonal to each other and to the array axis. The analysis simplifies because there is no cross-coupling of the modes in the scattering matrix equations. However, the electric and magnetic dipoles in the array are coupled through the fields scattered by the spheres. The assumption that a dipolar traveling wave along the array axis can be supported by the array of spheres yields a pair of equations for determining the traveling wave propagation constant as a function of the sphere size, inter-sphere separation distance, the sphere permittivity and permeability, and the free-space wave number. These equations are obtained by equating the electric (magnetic) field incident on any sphere of the array with the sum of the electric (magnetic) fields scattered from all the other spheres in the array. Both equations include a parameter equal to the ratio of the unknown normalized coefficients of the electric and magnetic dipole fields. By eliminating this parameter between the two equations, a single transcendental equation is obtained that can be easily solved numerically for the traveling wave propagation constant. Plots of the k - β diagram for different types and sizes of spheres are shown. Interestingly, for certain spheres and separations it is possible to have multiple traveling waves supported by the array. Backward traveling waves are also shown to exist in narrow frequency bands for arrays of spheres with suitable permittivity and permeability.

In this paper, a method based on the Radiative Energy Transfer theory (RET) to estimate the scattered radio signals from isolated groups of trees is presented. The proposed method consists of measuring the re-radiation function of each tree in the group, parameterising the function and subsequently using these in a discrete algorithm to estimate the overall attenuation at any location within the forest scenario. The discrete algorithm (dRET) presented here has some major improvements over previously published ones, offering substantially enhanced applicability. These improvements allow the use of larger vegetation cells, the enhancement of angular resolution of predicted results and the consideration of the receiving antenna radiation pattern. The estimated received signals using the re-radiation function, on the one hand, and its parameterised counterpart, on the other hand, are compared with measurements performed inside an anechoic chamber on Ficus Benjamina indoor plants at 20 and 62.4 GHz. The overall model performance was assessed in terms of RMS error between measured and predicted results.

This paper presents the analysis of hybrid cascode compensation scheme, merged Ahuja and improved Ahuja style compensation methods, which is used in two-stage CMOS operational transconductance amplifiers (OTAs). The open loop signal transfer function is derived to allow the accurate estimation of the poles and zeros. This analytical approach shows that the non-dominant poles and zeros of the hybrid cascode compensation are about 40 percent greater than those of the conventional cascode compensation. Circuit level simulation results are provided to show the accuracy of the calculated expressions and also the usefulness of the proposed cascode compensation technique.

A lasing charactrization of a Brillouin/erbium optical fiber laser (BEFL) is experimentally discussed. In the BEFL, an erbium-doped fiber amplifier (EDFA) is incorporated into the Brillouin laser resonator to enhance small Brillouin gain, which makes the configuration of the Brillouin laser resonator easy and flexible. The experimental results show that the output power of the BEFL has a threshold against the Brillouin pump power, and above the Brillouin threshold, the output power increases linearly with the EDFA pump power. The BEFL threshold decreases with increasing the length of the optical fiber in the laser resonator used as a Brillouin gain medium. The BEFL oscillates in a stable single longitudinal mode because the bandwidth of the Brillouin gain profile is very narrow ( 30 MHz). The relative intensity noise (RIN) and the spectral lineshape were measured. The noise floor level decreases with increasing the EDFA pump power, and the full-width at half maximum of the BEFL was measured to be about 8 kHz.

The electrostatic discharge (ESD) effect in GMR heads in the deshunting process is studied in order to prevent the damage in this process. The simulation and experiment results are investigated and compared. It is found from these results that sequences of deshunting process, currently operating, can cause the damage of GMR heads due to the ESD effect, based on the charged device model, CDM. This also shows that the voltage across GMR head, as the tweezers is used, can be raised up to 3.7 V which is about harmful to damage the head. Examples of damage heads confirmed by the SEM are also shown.

Polling I/O mechanisms on the Unix platform such as select() and poll() cause high processing overhead when they are used in a heavily-loaded network server with many concurrent open sockets. Large waste of processing power incurs not only service degradation but also various troubles such as high electronic power consumption and worsened MTBF of server hosts. It is thus a serious issue especially in large-scale service providers such as an Internet data center (iDC) where a great number of heavily-loaded network servers are operated. As a solution of this problem, we propose a technique of fine-grained control on the invocation intervals of the polling I/O function. The uniqueness of this study is the utilization of POSIX real-time scheduling to enable the fine-grained execution control. Although earlier solutions such as an explicit event delivery mechanism also addressed the problem, they require major modification in the OS kernel and transition from the traditional polling I/O model to the new explicit event-notification model. On the other hand, our technique can be implemented with low cost because it just inserts a few small blocks of codes into the server program and does not require any modification in the OS kernel.

The discovery of the Turbo codes has driven research on the creation of new signal detection concepts that are, in general, referred to as the Turbo approach. Recently, this approach has made a drastic change in creating signal detection techniques and algorithms such as equalization of inter-symbol interference (ISI) experienced by broadband single carrier signaling over mobile radio channels. A goal of this paper is to provide readers with broad views and knowledge of the Turbo concept-based Multiple-Input Multiple-Output (MIMO) signal transmission techniques. How the techniques have been developed in various applications and how they perform in real-field environments are introduced.

This paper investigates the usefulness of a new priority list for two-processor scheduling problem of program nets. Firstly, we discuss the weakness of a previously proposed priority list and then introduce a new priority list. Through simulation experiment we show that the new priority list is better than the previous one and can generate the same length of schedules as GA scheduling, which implies the new priority list can generate approximately optimal schedules.

In order to control the moving speed of an endoscopic capsule in the human intestine, electrical stimulation method is proposed in this paper. The miniaturized endoscopic capsule with the function of various electrical stimulations has been designed and implemented. An in-vivo animal experiment has been performed to show the ability of controlling the movement speed of the endoscopic capsule according to the level of electrical stimulation. In-vivo experiments were performed by inserting the implemented capsule into a pig's intestinal tract. From the experimental results, the activation of peristaltic movement and the relationship between the moving speed of capsule and the stimulation amplitude could be found. It is shown that the moving speed of capsule in the intestine can be controlled by adjustment of the stimulation level applied in the capsule electrodes. The results of the in-vivo experiment verify that the degree of contraction in the intestinal tract is closely related with the level of stimulating electrical voltage, suggesting that the moving speed of capsule in the human gastrointestinal tract can be controlled by externally adjusting the amplitude of stimulating pulse signal.

Simultaneous recordings of eight channel surface myoelectric signals (EMGs) of the biceps brachii muscles of seven subjects were measured in isovelocity elbow flexion against constant load torque. The velocity was 10, 15, 20 and 25 degree/s and the load torque was 5-15 % of the torque obtained at the maximum voluntary contraction (MVC). Individual motor units were identified from the eight-channel surface EMG, by tracking the waveform change which originated from the change of relative position of muscle fiber and electrode. In the low-load (5 and 7% MVC) experiment, 36 examples of recruitment and 22 examples of derecruitment were measured. In the middle-load (10 and 15% MVC) experiment, most of the motor units did not show an obvious change in the firing rate with the elbow joint angle. Average of the firing rates of all the motor units measured at the elbow angle of 0 to 120 degree (13.3-14.7 Hz) did not depend on flexion velocity between 10 to 25 degree/s. It was concluded that the firing rates of the activated MUs were almost constant and that some MUs were recruited and derecruited during the isovelocity flexion movements. These are the first findings.

In this letter, two kinds of MOS operational transconductance amplifiers (OTAs) based on combiners are presented. Each OTA has the following advantages; one of the proposed OTAs (OTA-1) can be operated at low supply voltage and the other OTA (OTA-2) has wide bandwidth. Through HSPICE simulations with a standard 0.35 µm CMOS device parameters, the operation under the supply voltage of 1.5 V for OTA-1 and the -3 dB bandwidth of several gigahertz for OTA-2 are confirmed.

Embedded systems are used in broad fields. They are one of the indispensable and fundamental technologies in a highly informative society in recent years. As embedded systems are large-scale and complicated, it is prosperous to design and develop a system LSI (Large Scale Integration). The structure of the system LSI has been increasing complexity every year. The degree of improvement of its design productivity has not caught up with the degree of its complexity by conventional methods or techniques. Hence, an idea for the design of a system LSI which has the flow of describing specifications of a system in UML (Unified Modeling Language) and then designing the system in a system level language has already proposed. It is important to establish how to convert from UML to a system level language in specification description or design with the idea. This paper proposes, extracts and verifies transformation rules from UML to SpecC which is one of system level languages. SpecC code has been generated actually from elements in diagrams in UML based on the rules. As an example to verify the rules, "headlights control system of a car" is adopted. SpecC code has been generated actually from elements in diagrams in UML based on the rules. It has been confirmed that the example is executed correctly in simulations. By using the transformation rules proposed in this paper, specification and implementation of a system can be connected seamlessly. Hence, it can improve the design productivity of a system LSI and the productivity of embedded systems.

This letter presents a method to extract vascular structures from magnetic resonance angiography (MRA) volumes based on the geometric variational principle. A minimal function is coupled with flux maximizing geometric flows and the geodesic active surface model while the geometrical description of vessel structure is added. Furthermore, the level set method represents the surface evolution as it is intrinsic and topologically flexible.

This paper presents an overview of four on-going European research projects in the field of mobile and wireless communications leading to the next generations of wireless communications. The projects started in 2004. They investigate requirements and definition of access technology, network architecture, antennas and propagation, security, services, applications and socio-economic impact.

A high-speed transconductance-C-opamp integrator using a current-feedback amplifier is proposed. The integrator has good frequency response compared with a conventional transconductance-C-opamp integrator using a voltage-feedback amplifier. The current-feedback amplifier shifts the second pole of the proposed integrator to the upper frequency. The frequency is proportional to the current gain of the current-feedback amplifier. The proposed integrator can eliminate effects of the parasitics at the output node of the transconductance since the voltage at the node is fixed. One of the circuit examples of the proposed integrator is shown. Its validity is confirmed through HSPICE simulations. The proposed integrator works as predicted up to 260 MHz.

An electromagnetic (EM) inverse scattering problem that involves the reconstruction of microwave images for dielectric objects is considered in this paper. This ill-posed and nonlinear problem is treated as a global optimization problem, and is solved by the application of micro-genetic algorithm (m-GA). The reconstructed results obtained by m-GA have shown that it is an effective technique for microwave imaging and satisfactory performance is achieved when compared with the conventional genetic algorithms.

When a fixed free-running crystal is used for sampling time generation at a DMT receiver, Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) are introduced by sampling time error. The ICI becomes more serious as the DMT symbol length increases. In this letter, the effects of sampling clock offset are investigated in the time domain using a new notion of Inter-sample Interference (IsI) instead of ISI and ICI. Based on the IsI analysis, we propose a new frequency domain timing error correction scheme.

This paper proposed the advantages of using a 2D/3D hybrid imagery system over the use of 3D by itself. A hybrid imagery system was created by projecting a 3D (stereo) image in between and overlapping onto two adjacent 2D images. The negative effect where 2D and 3D images overlap was studied and resolved. Then sensations subject experienced from the visual cues under the different conditions were attained. Participant's sensations while looking at the different forms of imagery on both a flat screen and a flat/inclined screen combination were then attained. The data for the 2D/3D hybrid system were compared with that attained for a 3D image system on its own (without 2D images). Results indicate that there are benefits to using a 2D/3D hybrid system over 3D by itself.

In this paper, we propose a proof scheme of shuffle, which is an honest verifier zero-knowledge proof of knowledge such as the protocols by Groth and Furukawa. Unlike the previous schemes proposed by Furukawa-Sako, Groth, and Furukawa, our scheme can be used as the shuffle of the elements encrypted by Paillier's encryption scheme, which has an additive homomorphic property in the message part. The ElGamal encryption scheme used in the previous schemes does not have this property.

In this study, a cascade open-short-thru (COST) de-embedding procedure is proposed for the first time for on-wafer device characterization in the RF/microwave frequency regime. This technique utilizes the "open" and "short" dummy structures to de-embed the probe-pad parasitics of a device-under-test (DUT). Furthermore, to accurately estimate the input/output interconnect parasitics, including the resistive, inductive, capacitive, and conductive components, the "thru" dummy device has been characterized after probe-pad de-embedding. With the combination of transmission-line theory and cascade-configuration concept, this method can efficiently generate the scalable and repeatable interconnect parameters to completely eliminate the redundant parasitics of the active/passive DUTs of various device sizes and interconnect dimensions. Consequently, this method is very suitable for the on-wafer automatic measurement.