Linear phase paraunitary filter bank with filters of differentlengths and its application in image compression

In this paper, the theory, structure, design, and implementation of a new class of linear-phase paraunitary filter banks (LPPUFBs) are investigated. The novel filter banks with filters of different lengths can be viewed as the generalized lapped orthogonal transforms (GenLOTs) with variable-length basis functions. Our main motivation is the application in block-transform-based image coding. Besides having all of the attractive properties of other lapped orthogonal transforms, the new transform takes advantage of its long, overlapping basis functions to represent smooth signals in order to reduce blocking artifacts, whereas it reserves short basis functions for high-frequency signal components like edges and texture, thereby limiting ringing artifacts. Two design methods are presented, each with its own set of advantages: the first is based on a direct lattice factorization, and the second enforces certain relationships between the lattice coefficients to obtain variable length filters. Various necessary conditions for the existence of meaningful solutions are derived and discussed in both cases. Finally, several design and image coding examples are presented to confirm the validity of the theory     

Modulation Transfer Noise Effects from a Continuous Digital Carrier to FDM/FM Carriers in Memoryless Nonlinear Devices

An analysis of the modulation transfer noise effects from a continuous (nonbursty) digital carrier to multiple FDM/FM carriers in a common memoryless nonlinear amplifier (e.g., satellite transponder TWTA) is presented. It is shown that the modulation transfer noise, which is caused by the random envelope variations of the digital carrier due to the random data patterns and filtering of the PSK pulses, consists of both discrete and continuous spectral components in the baseband of the FDM/FM carriers. Numerical examples in terms of the noise power ratio as well as a comparison between measured and computed results are given. In general, the discrete or tonal interference component at the symbol rate of the digital carrier is quite significant. Results of this paper should be useful in the planning of FDMA satellite transponders employing the mixed PSK-FM mode of operation.     

Simulation of the High-Frequency Response of a Heterogeneous Ground through the Finite Difference Technique

To simulate the propagation of an electromagnetic plane wave in an inhomogeneous ground, the finite difference approach can be used. One of the main problems in using this method is imposing the boundary conditions near the ground surface, especially at high frequency. Indeed, for the E polarization, the upper top of the numerical grid must be sufficiently far away from the air-ground interface in order to neglect the field due to the heterogeneities and the discretization of the atmosphere is necessary. For magneto-telluric modeling, improved boundary conditions have already been proposed. This paper deals with a new condition, valid everywhere in air and which can be applied for E and H polarization. Thus even at high frequency, as for radar applications, only one line is added to the grid discretizing the ground.     

Improved Graphitic Structure of Continuous Carbon Nanofibers via Graphene Oxide Templating

Continuous carbon nanofibers (CNF) present an attractive building block for a variety of multifunctional materials and devices. However, the carbonization of poly(acrylonitrile) (PAN) precursors usually results in CNFs with poor graphitic structure and, consequently, modest/non‐optimized properties. This paper reports that the graphitic structure of CNFs can be improved with an addition of a small amount of graphene oxide into PAN prior to processing. Continuous CNFs with 1.4 wt% of graphene oxide nanoparticles are prepared from PAN solutions by electrospinning, stabilized, and carbonized at 800 °C, 1200 °C, and 1850 °C. While the as‐prepared graphene oxide‐filled PAN nanofibers exhibit a considerable reduction in polymer crystallinity, Raman analysis of the carbonized nanofibers shows that both templating with graphene oxide and increasing the carbonization temperature significantly improve the graphitic order in CNFs. The effect of graphene oxide is more significant at higher carbonization temperatures. Selected area electron diffraction analysis of individual nanofibers reveals increased graphitic order and preferred orientation both in the vicinity of visible graphene oxide nanoparticles and in the regions where nanoparticles were not visible. These results indicate a possibility of global templating in CNFs, where the addition of a small amount of graphene oxide nanoparticles can template the formation of good, preferentially oriented graphitic crystallites in CNFs, leading to improved structure and mechanical and transport properties.     

Stereo Video Retargeting with Representative Seams in a Group of Stereoscopic Frames

The important requirements for stereo video retargeting are threefold: keeping temporal coherence, preventing depth distortion, and minimizing shape distortions of the retargeted video. To meet these requirements, the left and right video sequences are divided into groups of frames (GoFs), where the GoF is a basic unit for the seam carving and we assign a set of fixed seams for all frames within the GoF. To determine the fixed seams for each GoF, we need to find the GoF boundary in the video first. Then, the representative frame for each GoF is generated by considering the spatial saliency and temporal coherence. Also, the confidence of the stereoscopic correspondence between the left and right frames is considered to prevent depth distortion.     

Image superresolution using support vector regression.

A thorough investigation of the application of support vector regression (SVR) to the superresolution problem is conducted through various frameworks. Prior to the study, the SVR problem is enhanced by finding the optimal kernel. This is done by formulating the kernel learning problem in SVR form as a convex optimization problem, specifically a semi-definite programming (SDP) problem. An additional constraint is added to reduce the SDP to a quadratically constrained quadratic programming (QCQP) problem. After this optimization, investigation of the relevancy of SVR to superresolution proceeds with the possibility of using a single and general support vector regression for all image content, and the results are impressive for small training sets. This idea is improved upon by observing structural properties in the discrete cosine transform (DCT) domain to aid in learning the regression. Further improvement involves a combination of classification and SVR-based techniques, extending works in resolution synthesis. This method, termed kernel resolution synthesis, uses specific regressors for isolated image content to describe the domain through a partitioned look of the vector space, thereby yielding good results.     

Fabricating Strong and Stiff Bioplastics from Whole Spirulina Cells

Since the 1950s, 8.3 billion tonnes (Bt) of virgin plastics have been produced, of which around 5 Bt have accumulated as waste in oceans and other natural environments, posing severe threats to entire ecosystems. The need for sustainable bio-based alternatives to traditional petroleum-derived plastics is evident. Bioplastics produced from unprocessed biological materials have thus far suffered from heterogeneous and non-cohesive morphologies, which lead to weak mechanical properties and lack of processability, hindering their industrial integration. Here, a fast, simple, and scalable process is presented to transform raw microalgae into a self-bonded, recyclable, and backyard-compostable bioplastic with attractive mechanical properties surpassing those of other biobased plastics such as thermoplastic starch. Upon hot-pressing, the abundant and photosynthetic algae spirulina forms cohesive bioplastics with flexural modulus and strength in the range 3–5 GPa and 25.5–57 MPa, respectively, depending on pre-processing conditions and the addition of nanofillers. The machinability of these bioplastics, along with self-extinguishing properties, make them promising candidates for consumer plastics. Mechanical recycling and fast biodegradation in soil are demonstrated as end-of-life options. Finally, the environmental impacts are discussed in terms of global warming potential, highlighting the benefits of using a carbon-negative feedstock such as spirulina to fabricate plastics.     

Synergistic Enhancement of Luminescent and Ferroelectric Properties through Multi-Clipping of Tetraphenylethenes

Synergistically enhancing luminescent and ferroelectric ( SELF ) properties are observed from a tetraphenylethene ( TP ) substituted with clipping groups ( C ), where the C is consisting of a 4-[3,5-bis-(3-decyloxy-styryl)-styryl]-phenyl ( DOS ) unit. The DOS units of TPCn are self-assembled via intermolecular interaction to clip themselves and induce TP aggregation, as evidenced by clip-induced quenching of emission at DOS units ( E _clip ) accompanied by aggregation-induced emission enhancement of TPs ( E _AIE ). TPC4 demonstrates strong photoluminescence in a dilute chloroform solution and large E_AIE in aqueous (>50%) THF solution. TPCn demonstrates SELF properties in film state, with high quantum yields of photoluminescence (>80%) and ferroelectric switching. Due to the introduction of four clips, TPC4 has a higher remnant polarization ( P _r  =  2.27 µC cm⁻²) at room temperature than TPC1. TPC4 is successfully employed in a light-emitting electrochemical cell to achieve over 1290 cd m⁻² under pulsed current conditions. The TPC4 film on a flexible substrate produced a piezoelectric output voltage of up to 0.13 V and a current density of 1.14 nA cm⁻² upon bending. These results indicate that the side chain clipping and TP aggregation resulted in unprecedented flexible SELF properties in a single compound, offering simultaneous enhancement of electroluminescence, mechanical sensitivity, and energy harvesting capacity.     

Design and Implementation of a Reconfigurable Mobile Game Controller on Smartphone

Expansion of games industry came in modern life, accompanied with innovative features in a game controller. Nowadays mobile industry is booming with the expansion of the variety of novel technologies, such as the use of 3D accelerometer sensors, high resolution cameras, the capability of connecting to wireless networks and so on. Therefore, a smartphone can be added with the game control functions to become a mobile game controller. In this paper, we propose the design and implementation of making a mobile phone as a game controller using User Datagram Protocol socket programming. This system is developed by Java 2 Standard Edition and Google Android Software Development Kits which has already provided sensor and multi-touch APIs. We successfully realize a reconfigurable mobile game controller on a mobile smartphone to interact with the existing digital games by mapping control functions on the server. Acceptable performance is shown to validate the effectiveness of our solution.     

A fully scalable motion model for scalable video coding.

Motion information scalability is an important requirement for a fully scalable video codec, especially for decoding scenarios of low bit rate or small image size. So far, several scalable coding techniques on motion information have been proposed, including progressive motion vector precision coding and motion vector field layered coding. However, it is still vague on the required functionalities of motion scalability and how it collaborates flawlessly with other scalabilities, such as spatial, temporal, and quality, in a scalable video codec. In this paper, we first define the functionalities required for motion scalability. Based on these requirements, a fully scalable motion model is proposed along with tailored encoding techniques to minimize the coding overhead of scalability. Moreover, the associated rate distortion optimized motion estimation algorithm will be provided to achieve better efficiency throughout various decoding scenarios. Simulation results will be presented to verify the superiorities of proposed scalable motion model over nonscalable ones.