Multilayered volumetric composite right/left handed metamaterial structures are investigated. The present structure is composed of conducting mesh plates and dielectric layers including dielectric resonators. The 2-D composite right/left handed metamaterial structure is designed for the in-plane propagation. Propagation mode analysis was made for the volumetric structure under the periodic boundary condition along the normal to the layers as well as for finite number of layered type for comparison. The negative-refractive-index planar lenses were designed and fabricated for the demonstration. It is found from the numerical simulation that the beam focusing through the planar lens with large number of layers is clearly confirmed in both magnitude and phase distribution of the fields. On the other hand, for small number of layers, the beam spot is not found in the magnitude distribution due to the effect of discontinuities between air and designed structure at the top and bottom surfaces, but is still found in the phase distribution. The effect of number of stacked layers on the propagation characteristics is discussed by comparing the numerical simulation results with the measurement.

The tiled-display system has been used as a Computer Supported Cooperative Work (CSCW) environment, in which multiple local (and/or remote) participants cooperate using some shared applications whose outputs are displayed on a large-scale and high-resolution tiled-display, which is controlled by a cluster of PC's, one PC per display. In order to make the collaboration effective, each remote participant should be aware of all CSCW activities on the titled display system in real-time. This paper presents a capturing and delivering mechanism of all activities on titled-display system to remote participants in real-time. In the proposed mechanism, the screen images of all PC's are periodically captured and delivered to the Merging Server that maintains separate buffers to store the captured images from the PCs. The mechanism selects one tile image from each buffer, merges the images to make a screen shot of the whole tiled-display, clips a Region of Interest (ROI), compresses and streams it to remote participants in real-time. A technical challenge in the proposed mechanism is how to select a set of tile images, one from each buffer, for merging so that the tile images displayed at the same time on the tiled-display can be properly merged together. This paper presents three selection algorithms; a sequential selection algorithm, a capturing time based algorithm, and a capturing time and visual consistency based algorithm. It also proposes a mechanism of providing several virtual cameras on tiled-display system to remote participants by concurrently clipping several different ROI's from the same merged tiled-display images, and delivering them after compressing with video encoders requested by the remote participants. By interactively changing and resizing his/her own ROI, a remote participant can check the activities on the tiled-display effectively. Experiments on a 32 tiled-display system show that the proposed merging algorithm can build a tiled-display image stream synchronously, and the ROI-based clipping and delivering mechanism can provide individual views on the tiled-display system to multiple remote participants in real-time.

The aim of this study is to develop a new whole-body averaged specific absorption rate (SAR) estimation method based on the external-cylindrical field scanning technique. This technique is adopted with the goal of simplifying the dosimetry estimation of human phantoms that have different postures or sizes. An experimental scaled model system is constructed. In order to examine the validity of the proposed method for realistic human models, we discuss the pros and cons of measurements and numerical analyses based on the finite-difference time-domain (FDTD) method. We consider the anatomical European human phantoms and plane-wave in the 2 GHz mobile phone frequency band. The measured whole-body averaged SAR results obtained by the proposed method are compared with the results of the FDTD analyses.

In this paper, we propose a novel feature named histogram of template (HOT) for human detection in still images. For every pixel of an image, various templates are defined, each of which contains the pixel itself and two of its neighboring pixels. If the texture and gradient values of the three pixels satisfy a pre-defined formula, the central pixel is regarded to meet the corresponding template for this formula. Histograms of pixels meeting various templates are calculated for a set of formulas, and combined to be the feature for detection. Compared to the other features, the proposed feature takes texture as well as the gradient information into consideration. Besides, it reflects the relationship between 3 pixels, instead of focusing on only one. Experiments for human detection are performed on INRIA dataset, which shows the proposed HOT feature is more discriminative than histogram of orientated gradient (HOG) feature, under the same training method.

This paper deals with the influence of metal cover planes close to SMD filter structures. The low-pass structures are used for EMC purpose and work in a frequency range of 100 kHz to 4 GHz. It will be shown by both measurement and simulation that a close cover plane changes the filter behavior significantly in dependency of the filter component used. For low and high impedance filter structures different influences are obtained; a parameter study was carried out in order to derive design rules.

We present a full description of a polarization-independent athermal differential quadrature phase shift keying (DQPSK) demodulator that employs silica-based planar lightwave circuit (PLC) technology. Silica-based PLC DQPSK demodulator has good characteristics including low polarization dependence, mass producibility, etc. However delay line interferometer (DLI) of demodulator had the large temperature dependence of its optical characteristics, so it required large power consumption to stabilize the chip temperature by the thermo-electric cooler (TEC). We previously made a quick report about an athermal DLI to reduce a power consumption by removing the TEC. In this paper, we focus on the details of the design and the fabrication method we used to achieve the athermal characteristics, and we describe the thermal stability of the signal demodulation and the reliability of our demodulator. We described two athermalization methods; the athermalization of the transmission spectrum and the athermalization of the polarization property. These methods were successfully demonstrated with keeping a high extinction ratio and a small footprint by introducing a novel interwoven DLI configuration. This configuration can also limit the degradation of the polarization dependent phase shift (PDf) to less than 1/10 that with the conventional configuration when the phase shifters on the waveguide are driven. We used our demodulator and examined its demodulation performance for a 43 Gbit/s DQPSK signal. We also verified its long-term reliability and thermal stability against the rapid temperature change. As a result, we confirmed that our athermal demodulator performed sufficiently well for use in DQPSK systems.

A novel approach is proposed for miniaturizing the unit cell size of electromagnetic bandgap (EBG) structures that suppress power plane noise. In this approach, open stubs are introduced into the shunt circuits of these EBG structures. Since the stub length determines the resonant frequencies of the shunt circuit, the proposed structures can maintain the bandgaps at lower frequencies without increasing the unit cell size. The bandgap frequencies were estimated by dispersion analysis based on the Bloch theorem and full-wave simulations. Sample boards of the proposed EBG structures were fabricated with a unit cell size of 2.1 mm. Highly suppressed noise propagation over the estimated frequency range of 1.9-3.6 GHz including the 2.4-GHz wireless-LAN band was experimentally demonstrated.

The purpose of this study is to estimate the possible effect of cellular radio on implantable cardiac pacemakers in elevators. We previously investigated pacemaker EMI in elevator by examining the E-field distribution of horizontal plane at the height of expected for implanted pacemakers inside elevators. In this paper, we introduce our method for estimating EMI impact to implantable cardiac pacemakers using EMF distributions inside the region of the human body in which pacemakers are implanted. Simulations of a human phantom in an elevator are performed and histograms are derived from the resulting EMF distributions. The computed results of field strengths are compared with a certain reference level determined from experimentally obtained maximum interference distance of implantable cardiac pacemakers. This enables us to carry out a quantitative evaluation of the EMI impact to pacemakers by cellular radio transmission. This paper uses a numerical phantom model developed based on an European adult male. The simulations evaluate EMI on implantable cardiac pacemakers in three frequency bands. As a result, calculated E-field strengths are sufficiently low to cause the pacemaker to malfunction in the region examined.

The planar Hajos calculus (PHC) is the Hajos calculus with the restriction that all the graphs that appear in the construction (including a final graph) must be planar. The degree-d planar Hajos calculus (PHC(dd)) is PHC with the restriction that all the graphs that appear in the construction (including a final graph) must have maximum degree at most d. We prove the followings: (1) If PHC is polynomially bounded, then for any d ≥ 4, PHC(dd+2) can generate any non-3-colorable planar graphs of maximum degree at most d in polynomial steps. (2) If PHC can generate any non-3-colorable planar graphs of maximum degree 4 in polynomial steps, then PHC is polynomially bounded.

Cancelable approaches for biometric person authentication have been studied to protect enrolled biometric data, and several algorithms have been proposed. One drawback of cancelable approaches is that the performance is inferior to that of non-cancelable approaches. In this paper, we propose a scheme to improve the performance of a cancelable approach for online signature verification. Our scheme generates two cancelable dataset from one raw dataset and uses them for verification. Preliminary experiments were performed using a distance-based online signature verification algorithm. The experimental results show that our proposed scheme is promising.

Secure channels can be realized by an authenticated key exchange (AKE) protocol that generates authenticated session keys between the involving parties. In, Shin et al., proposed a new kind of AKE (RSA-AKE) protocol whose goal is to provide high efficiency and security against leakage of stored secrets as much as possible. Let us consider more powerful attacks where an adversary completely controls the communications and the stored secrets (the latter is denoted by "replacement" attacks). In this paper, we first show that the RSA-AKE protocol is no longer secure against such an adversary. The main contributions of this paper are as follows: (1) we propose an RSA-based leakage-resilient AKE (RSA-AKE2) protocol that is secure against active attacks as well as replacement attacks; (2) we prove that the RSA-AKE2 protocol is secure against replacement attacks based on the number theory results; (3) we show that it is provably secure in the random oracle model, by showing the reduction to the RSA one-wayness, under an extended model that covers active attacks and replacement attacks; (4) in terms of efficiency, the RSA-AKE2 protocol is comparable to in the sense that the client needs to compute only one modular multiplication with pre-computation; and (5) we also discuss about extensions of the RSA-AKE2 protocol for several security properties (i.e., synchronization of stored secrets, privacy of client and solution to server compromise-impersonation attacks).

A novel analysis model for post-wall waveguide T-junctions is proposed. Equivalent solid-walls for the post-walls to have equal guided wavelength are corrected in the analysis model so that the wall thickness for the coupling windows is set to the difference in the width between the post-wall and the solid-wall waveguides. The accuracy of the proposed model is confirmed by comparing it to an HFSS analysis for the real structure of the post-wall waveguide T-junction including the post surfaces. 61.25 GHz model antennas are fabricated for experimental verification. The reflection of the antenna designed by the modified analysis model is suppressed to below -15 dB over a 5.6 GHz bandwidth, while that in the antenna designed by the conventional model is larger than -15 dB around the design frequency.

Traditionally, popular synonym acquisition methods are based on the distributional hypothesis, and a metric such as Jaccard coefficients is used to evaluate the similarity between the contexts of words to obtain synonyms for a query. On the other hand, when one tries to compile and clean a thesaurus, one often already has a modest number of synonym relations at hand. Could something be done with a half-built thesaurus alone? We propose the use of spectral methods and discuss their relation to other network-based algorithms in natural language processing (NLP), such as PageRank and Bootstrapping. Since compiling a thesaurus is very laborious, we believe that adding the proposed method to the toolkit of thesaurus constructors would significantly ease the pain in accomplishing this task.

With the increasing demand for services provided by communication networks, quality and reliability of such services as well as confidentiality of data transfer are becoming ones of the highest concerns. At the same time, because of growing hacker's activities, quality of provided content and reliability of its continuous delivery strongly depend on integrity of data transmission and availability of communication infrastructure, thus on information security of a given IT landscape. But, the amount of resources allocated to provide information security (like security staff, technical countermeasures and etc.) must be reasonable from the economic point of view. This fact, in turn, leads to the need to employ a forecasting technique in order to make planning of IT budget and short-term planning of potential bottlenecks. In this paper we present an approach to make such a forecasting for a wide class of information security related incidents (ISRI) -- unambiguously detectable ISRI. This approach is based on different auto regression models which are widely used in financial time series analysis but can not be directly applied to ISRI time series due to specifics related to information security. We investigate and address this specifics by proposing rules (special conditions) of collection and storage of ISRI time series, adherence to which improves forecasting in this subject field. We present an application of our approach to one type of unambiguously detectable ISRI -- amount of spam messages which, if not mitigated properly, could create additional load on communication infrastructure and consume significant amounts of network capacity. Finally we evaluate our approach by simulation and actual measurement.

Quantum key distribution (QKD) systems can generate unconditionally secure common keys between remote users. Improvements of QKD performance, particularly in key generation rate, have been required to meet current network traffic. A high-speed QKD system should be equipped with low-loss receivers with high visibility, highly efficient photon detectors with small dark count probability. A solution to these issues is to employ planar lightwave circuit (PLC) interferometers, single photon detection circuits and modules, together with multi-wavelength channels transmission using wavelength division multiplexing (WDM) technique.

Owing to their ultra-wideband characteristics, tapered slot antennas (TSAs) are used as element antennas in wideband phased arrays. However, when the size of a TSA is reduced in order to prevent the generation of a grating lobe during wide-angle beam scanning, the original ultra-wideband characteristics are degraded because of increased reflections from the ends of the tapered slot aperture. To overcome this difficulty, we propose a new antenna structure in which parallel-plate waveguides are added to the TSA. The advantage of this new structure is that the reflection characteristics of individual antenna elements are not degraded even if the width of the antenna aperture is very small, i.e., approximately one-half the wavelength of the highest operating frequency. In this study, we propose a procedure for designing the new antenna through numerical simulations by using the FDTD method. In addition, we verify the performance of the antenna array by experiments.

Tin and its alloys have been applied for the plating of electrical contacts for low electrical power conditions. In particular, tin-plated contacts are widely used as connector contacts in automotive applications and as make-break contacts in keyboard switches. In the relationship between contact resistance (R) and contact load (W) for both solid and plated tin, singularities have been found. Previously established and well known theories on the deformation of contact interfaces cannot explain these singularities. In this study, to clarify these singularities, and to obtain a contact model explaining this phenomenon, contact traces for contact load were examined by SEM and STM. The obtained microscopic images indicated piling-up at the periphery of the contact area for both solid and plated tin. In this case the contact configuration comprised a platinum probe with a hemispherical tip surface and a flat tin surface for both solid and plated. When the probe was loaded, this tip of the probe sank into the soft tin surface owing to its lower hardness. In case of solid tin, the sinking of the probe surface into the tin surface causes piling-up around the periphery of the contact trace. In this deformation process, since the periphery of the indentation of the indented contact area severely slid against the surface of the platinum probe while applying a contact load, the contact resistance rapidly decreased with load. In this case, the center portion of the true contact area was not affected mechanically; thus, the surface film on the bottom portion of the deformed of the flat surface did not break down mechanically. On the other hand, in the case of a tin plated surface, similar piling up occurred; however, it was accompanied by scattering and separation of tin crystal grains from the surface. As a result of this process, a decrease in contact resistance similar to that for the solid tin occurred. Since the piling-up of the contact surface is a very important process in the application of connectors, the above-mentioned unusual characteristics were clarified in this study.

Hierarchical Identity-Based Encryption (HIBE) is a generalization of identity-based encryption that mirrors an organizational hierarchy, and allows the root Private Key Generator (PKG) to distribute the workload of key generations to lower-level PKGs. In Indocrypt'08, Ren and Gu proposed a new HIBE scheme, and claimed that their scheme is fully chosen-ciphertext secure in the standard model. However, by giving a concrete attack, we show that Ren-Gu's HIBE is even not chosen-plaintext secure.

An implantable WBAN path-loss model for a capsule endoscopy which is used for examining digestive organs, is developed by conducting simulations and experiments. First, we performed FDTD simulations on implant WBAN propagation by using a numerical human model. Second, we performed FDTD simulations on a vessel that represents the human body. Third, we performed experiments using a vessel of the same dimensions as that used in the simulations. On the basis of the results of these simulations and experiments, we proposed the gradient and intercept parameters of the simple path-loss in-body propagation model.

Electrical contacts are an important part of electrical circuits and many reliability problems are related to electrical contact failure. It is important to investigate the relationship between load and contact resistance which is an important factor of contact reliability. In this study, the effect of plated material and plated thickness on contact resistance was examined. The samples were constructed of a copper alloy with tin or silver plating. Contact configuration was hemispherical-flat contact. The contact resistance was measured by using a four-probe method with a load up to 40 N. The relation between indentation contact area (i.e. apparent contact area) and contact resistance was determined. As experimental results, the contact resistance depends on the indentation of the contact area. In the same contact area, tin-plated samples have higher resistance than those that are silver-plated due to their own resistivity. The constriction resistance of a plated layer, which depends on contact area, plated material and plated thickness, is analyzed by a theoretical solution, which is shown by R=Φρ /2a, using a surface resistance coefficient Φ . The theoretical results show almost good agreement with the experimental results. Thus, the indentation contact area (i.e. apparent contact area) is almost the same as the real contact area in this study.