An authenticated re‐encryption scheme for secure file transfer in named data networks

With the fast progress of the Internet and communication technologies, the digital communication is increasingly based on the architecture of TCP/IP. Nevertheless, in TCP/IP's architecture, there are limitations such as data uncertainty and flow overloading. In response to this, a novel architecture has been proposed, which is known as the named data network (NDN). Named data network is an alternative network architecture based on the data each user accesses. Users gain accesses to the data by using an adjacent router (node) that verifies the correctness of the data. In NDN, the router has the capability to store and search for the data. Hence, this architecture largely improves the disadvantages in TCP/IP's architecture. Named data network is a new proposal and relatively under‐researched now. Thus far, an adequate secure file transfer protocol is still unavailable for NDN. In some cases, files are broken or the source fails to authenticate, which results in the need to discover the owner of the file. Furthermore, we believe that NDN should involve an authentication mechanism in the secure file transfer protocol. In view of the above, this paper presents an authenticated re‐encryption scheme for NDN, which offers sender authentication, data confidentiality, and support for potential receivers. Finally, we also propose a security model for sender authentication and prove that the proposed scheme is secure.     

Growth and fatigue properties of pulsed laser deposited Pb1 − x La x (Zr y Ti z )O3 thin films with [0 0 /] preferred orientation

Growth of [0 0 /] preferentially oriented Pb_{1 - x} La _x (Zr _y Ti _z ) O₃ (PLZT) thin films was carried out by using targets of either tetragonal or rhombohedral structure. The tetragonal films grew in a similar manner to the rhombohedral films. Both the substrate temperature (500 or 550 C) and oxygen pressure (0.1 mbar, 10 Pa) required stringent control in order to deposit [0 0 /]-textured PLZT thin films. The ferroelectric and fatigue properties were examined.The films deposited on YBa₂Cu₃O_{7 - x} and CeO₂ coated silicon (YBCO/CeO₂/Si) substrates possessed substantially lower remanent polarization than those grown on YBCO coated SrTiO₃ (YBCO/STO) substrates; this is ascribed to inferior crystallinity of the PLZT/YBCO/CeO₂/Si films. The remanent polarization of tetragonal PLZT films was degraded insignificantly up to 10⁸ polarization switching cycles, whereas that of rhombohedral PLZT films was already reduced to 80% of the initial value after 10⁸ cycles. Low endurance of rhombohedral films was ascribed to the periodic stress induced when the inclined spontaneous polarization vector (P = [111]) switched. On the other hand, high endurance of tetragonal films was explained by the fact that the spontaneous polarization vector (P = [001]) lies along the film's normal such that switch cycles cause no lateral stress.     

One-dimensional ZnO nanostructures

The wide-gap semiconductor ZnO with nanostructures such as nanoparticle, nanorod, nanowire, nanobelt, nanotube has high potential for a variety of applications. This article reviews the fundamentals of one-dimensional ZnO nanostructures, including processing, structure, property, application and their processing-microstructure-property correlation. Various fabrication methods of the ZnO nanostructures including vapor-liquid-solid process, vapor-solid growth, solution growth, solvothermal growth, template-assisted growth and self-assembly are introduced. The characterization and properties of the ZnO nanostructures are described. The possible applications of these nanostructures are also discussed.     

Physical and chemical properties and adsorption type of activated carbon prepared from plum kernels by NaOH activation

Activated carbon was prepared from plum kernels by NaOH activation at six different NaOH/char ratios. The physical properties including the BET surface area, the total pore volume, the micropore ratio, the pore diameter, the burn-off, and the scanning electron microscope (SEM) observation as well as the chemical properties, namely elemental analysis and temperature programmed desorption (TPD), were measured. The results revealed a two-stage activation process: stage 1 activated carbons were obtained at NaOH/char ratios of 0-1, surface pyrolysis being the main reaction; stage 2 activated carbons were obtained at NaOH/char ratios of 2-4, etching and swelling being the main reactions. The physical properties of stage 2 activated carbons were similar, and specific area was from 1478 to 1887m(2)g(-1). The results of reaction mechanism of NaOH activation revealed that it was apparently because of the loss ratio of elements C, H, and O in the activated carbon, and the variations in the surface functional groups and the physical properties. The adsorption of the above activated carbons on phenol and three kinds of dyes (MB, BB1, and AB74) were used for an isotherm equilibrium adsorption study. The data fitted the Langmuir isotherm equation. Various kinds of adsorbents showed different adsorption types; separation factor (R(L)) was used to determine the level of favorability of the adsorption type. In this work, activated carbons prepared by NaOH activation were evaluated in terms of their physical properties, chemical properties, and adsorption type; and activated carbon PKN2 was found to have most application potential.     

The effects of boron penetration on p+ polysilicon gatedPMOS devices

The penetration of boron into and through the gate oxides of PMOS devices which employ p⁺ doped polysilicon gates is studied. Boron penetration results in large positive shifts in V_FB , increased PMOS subthreshold slope and electron trapping rate, and decreased low-field mobility and interface trap density. Fluorine-related effects caused by BF₂ implantations into the polysilicon gate are shown to result in PMOS threshold voltage instabilities. Inclusion of a phosphorus co-implant or TiSi₂ salicide prior to gate implantation is shown to minimize this effect. The boron penetration phenomenon is modeled by a very shallow, fully-depleted p-type layer in the silicon substrate close to the SiO ₂/Si interface     

Isolated-utterance speech recognition using hidden Markov modelswith bounded state durations

Hidden Markov models (HMMs) with bounded state durations (HMM/BSD) are proposed to explicitly model the state durations of HMMs and more accurately consider the temporal structures existing in speech signals in a simple, direct, but effective way. A series of experiments have been conducted for speaker dependent applications using 408 highly confusing first-tone Mandarin syllables as the example vocabulary. It was found that in the discrete case the recognition rate of HMM/BSD (78.5%) is 9.0%, 6.3%, and 1.9% higher than the conventional HMMs and HMMs with Poisson and gamma distribution state durations, respectively. In the continuous case (partitioned Gaussian mixture modeling), the recognition rates of HMM/BSD (88.3% with 1 mixture, 88.8% with 3 mixtures, and 89.4% with 5 mixtures) are 6.3%, 5.0%, and 5.5% higher than those of the conventional HMMs, and 5.9% (with 1 mixture), 3.9% (with 3 mixtures) and 3.1% (with 1 mixture), 1.8% (with 3 mixtures) higher than HMMs with Poisson and gamma distributed state durations, respectively     

Design of linear phase FIR filters using fractional derivative constraints

In this paper, the designs of linear phase FIR filters using fractional derivative constraints are investigated. First, the definition of fractional derivative is reviewed briefly. Then, the linear phase FIR filters are designed by minimizing integral squares error under the constraint that the ideal response and actual response have several same fractional derivatives at the prescribed frequency point. Next, the fractional maximally flat FIR filters are designed by letting the number of fractional derivative constraints be equal to the number of filter coefficients. Finally, numerical examples are demonstrated to show that the proposed method has larger design flexibility than the conventional integer derivative constrained methods.     

InGaAs-Capped InAs–GaAs Quantum-Dot Infrared Photodetectors Operating in the Long-Wavelength Infrared Range

A ten-period InAs-GaAs quantum-dot infrared photodetector (QDIP) with 8-nm In_0.15Ga_0.85 As capping layer grown after quantum-dot (QD) deposition is investigated. With reduced InAs QD coverage down to 2.0 mono-layers, responses at 10.4 and 8.4 mum are observed for the device under positive and negative biases, respectively. The phenomenon is attributed to the large Stark effect resulted from the asymmetric band diagrams of the device under different voltage polarities. The demonstration of long-wavelength infrared detections with the simple structures of the InGaAs-capped QDIP is advantageous for the development of multicolor QDIP focal-plane arrays.     

Design of robust envelope-constrained filter with orthonormal bases

In the continuous-time envelope-constrained (EC) filtering problem using an orthonormal filter structure, the aim is to synthesize an orthonormal filter such that the noise enhancement is minimized while the noiseless output response of the filter with respect to a specified input signal stays within the upper and lower bounds of the envelope. The noiseless output response of the optimum filter to the prescribed input signal touches the output boundaries at some points. Consequently, any disturbance in the prescribed input signal or error in the implementation of the optimal filter will result in the output constraints being violated. In this paper, we review a semi-infinite envelope-constrained filtering problem in which the constraint robustness margin of the filter is maximized, subject to a specified allowable increase in the optimal noisy power gain. Using a smoothing technique, it is shown that the solution of the optimization problem can be obtained by solving a sequence of strictly convex optimization problems with integral cost. An efficient optimization algorithm is developed based on a combination of the golden section search method and the quasi-Newton method