In this paper, we propose a new interference alignment (IA) scheme that jointly designs the linear transmitter and receiver for the 2-user MIMO X channel system, using minimum total mean square error criterion, subject to each transmitter power constraint. We show that transmitters and receivers under such criteria could be realized through a joint iterative algorithm. Considering the imperfection of channel state information (CSI), we also extend the minimum mean square error interference alignment schemes for the MIMO X channel with CSI estimation error. A robust iterative algorithm which is insensitve to CSI estimation error is proposed. Simulation results are also provided to demonstrate the proposed algorithm.

Owing to the concerns about electromagnetic interference (EMI) from wireless local area networks (WLAN), an investigation into its impact on medical equipment is carried out. The results indicate that there is no evidence of 802.11 Wireless LAN systems being unsafe for installation inside hospital premises and only one piece of equipment was found to be susceptible to IEEE 802.11b standard.

In this letter, an AGV based relay selection mechanism is developed to ensure relays reporting true information in wireless relay networks. The source selects relays based on the channel state information (CSI) of relay-destination links. Selfish relays may report fake CSI in order to obtain a better chance of being selected, whereas the source is not able to tell the reported in real or in false. In the proposed scheme, a relay node receives some payoffs from the destination with respect to the achievable data rate and also some compensations from the others in terms of the reported CSI of all relays. This mechanism not only enforces truth-telling upon relay nodes with maximum payoff but also ensures fairness among them. The equilibrium of payoff is attained when relay nodes report their true CSI. Simulation results demonstrate the theoretical solutions.

Recent works on MIMO receiver design were mainly focused on sphere decoding, which provides a trade-off between the performance and complexity by suitably choosing the “radius” or the number of candidates in the search space. Meanwhile, another approach, called poly-diagonalization and trellis detection, has been proposed to compromise the complexity and performance. In this paper, we compare various MIMO receiver algorithms in terms of both performance and complexity. The performance is evaluated in a frequency selective fading channel environment on the basis of orthogonal frequency division multiplexing with channel coding, for which the generation of soft decision values is crucial. The simulations show that the poly-diagonalization approach matches the performance of sphere decoding at similar computational complexity.

In this paper, we propose a spatially adaptive gradient-projection algorithm for the H.264 video coding standard to remove coding artifacts using local statistics. A hybrid method combining a new weighted constrained least squares (WCLS) approach and the projection onto convex sets (POCS) approach is introduced, where weighting components are determined on the basis of the human visual system (HVS) and projection set is defined by the difference between adjacent pixels and the quantization index (QI). A new visual function is defined to determine the weighting matrices controlling the degree of global smoothness, and a projection set is used to obtain a solution satisfying local smoothing constraints, so that the coding artifacts such as blocking and ringing artifacts can be simultaneously removed. The experimental results show the capability and efficiency of the proposed algorithm.

In this letter, a new terrain type classifier is proposed for polarimetric Synthetic Aperture Radar (Pol-SAR) images. This classifier uses the binary tree structure. The homogenous and inhomogeneous areas are first classified by the support vector machine (SVM) classifier based on the texture features extracted from the span image. Then the homogenous and inhomogeneous areas are, respectively, classified by the traditional Wishart classifier and the SVM classifier based on the texture features. Using a NASA/JPL AIRSAR image, the authors achieve the classification accuracy of up to 98%, demonstrating the effectiveness of the proposed method.

This paper presents various types of iterative progressive numerical methods (IPNMs) for the computation of electromagnetic (EM) wave scattering from many objects and reports comparatively the performance of these methods. The original IPNM is similar to the Jacobi method which is one of the classical linear iterative solvers. Then the modified IPNMs are based on other classical solvers like the Gauss-Seidel (GS), the relaxed Jacobi, the successive overrelaxation (SOR), and the symmetric SOR (SSOR) methods. In the original and modified IPNMs, we repeatedly solve linear systems of equations by using a nonstationary iterative solver. An initial guess and a stopping criterion are discussed in order to realize a fast computation. We treat EM wave scattering from 27 perfectly electric conducting (PEC) spheres and evaluate the performance of the IPNMs. However, the SOR- and SSOR-type IPNMs are not subject to the above numerical test in this paper because an optimal relaxation parameter is not possible to determine in advance. The evaluation reveals that the IPNMs converge much faster than a standard BEM computation. The relaxed Jacobi-type IPNM is better than the other types in terms of the net computation time and the application range for the distance between objects.

One of the most difficult problems that remains to be solved in wire interconnect architectures is the achievement of lower latency and higher concurrency on a shared bus or link without increasing the power and circuit overhead. Novel improvements in short distance on- and off-chip interconnects can be provided by using a multi-band RF interconnect (RF-I) system. Unlike the conventional current- or voltage-mode square wave signaling transceivers that use binary or multilevel baseband signals, the proposed RF-I transceiver uses high-frequency modulated RF passband signals with binary phase-shift keying (BPSK) modulation. The proposed low-overhead RF-I transceiver using 0.18-µm CMOS technology achieves an aggregate data rate of 4 Gb/s/pin between four I/Os (2Tx-to-2Rx) on a shared FR4 PCB line using two carriers of 6 GHz and 12 GHz. The two transceivers occupy an area of 0.077 mm2 and dissipate a power of about 25 mW with a power efficiency of 6.25 pJ/bit.

State Transition Matrix (STM) is a table-based modeling language that has been frequently used in industry for specifying behaviors of systems. Functional correctness of a STM design (i.e., a design developed with STM) could often be expressed as invariant properties. In this paper, we first present a formalization of the static and dynamic aspects of STM designs. Consequentially, based on this formalization, we investigate a symbolic encoding approach, through which a STM design could be bounded model checked w.r.t. invariant properties by using Satisfiability Modulo Theories (SMT) solving technique. We have built a prototype implementation of the proposed encoding and the state-of-the-art SMT solver - Yices, is used in our experiments to evaluate the effectiveness of our approach. Two attempts for accelerating SMT solving are also reported.

This paper introduces an interactive expression editing system that allows users to design facial expressions easily. Currently, popular example-based methods construct face models based on the examples of target face. The shortcoming of these methods is that they cannot create expressions for novel faces: target faces not previously recorded in the database. We propose a solution to overcome this limitation. We present an interactive facial-geometric-feature animation system for generating expressions of novel faces. Our system is easy to use. By click-dragging control points on the target face, on the computer screen display, unique expressions are generated automatically. To guarantee natural animation results, our animation model employs prior knowledge based on various individuals' expressions. One model prior is learned from motion vector fields to guarantee effective facial motions. Another, different, model prior is learned from facial shape space to ensure the result has a real facial shape. Interactive animation problem is formulated in a maximum a posterior (MAP) framework to search for optimal results by combining the priors with user-defined constraints. We give an extension of the Motion Propagation (MP) algorithm to infer facial motions for novel target faces from a subset of the control points. Experimental results on different facial animations demonstrate the effectiveness of the proposed method. Moreover, one application of our system is exhibited in this paper, where users create expressions for facial sketches interactively.

Various planar folded dipole antennas with feed lines are introduced and analyzed. With the added feed line, the planar folded dipole antenna has two resonance modes. Moreover, adjusting the spacing and width of the feed line improves the broadband characteristics of the antenna. The attached feed line has not only an impedance transforming characteristic but also a bandwidth transforming characteristic. The bandwidth transforming characteristic means that the feed line can broaden the bandwidth of folded dipole antenna. A way to reduce the antenna area is also studied, and the characteristics of the resulting compact antenna are analyzed.

Automatic recognition of finger gestures can be used for promotion of life quality. For example, a senior citizen can control the home appliance, call for help in emergency, or even communicate with others through simple finger gestures. Here, we focus on one-stroke finger gesture, which are intuitive to be remembered and performed. In this paper, we proposed and evaluated an accelerometer-based method for detecting the predefined one-stroke finger gestures from the data collected using a MEMS 3D accelerometer worn on the index finger. As alternative to the optoelectronic, sonic and ultrasonic approaches, the accelerometer-based method is featured as self-contained, cost-effective, and can be used in noisy or private space. A compact wireless sensing mote integrated with the accelerometer, called MagicRing, is developed to be worn on the finger for real data collection. A general definition on one-stroke gesture is given out, and 12 kinds of one-stroke finger gestures are selected from human daily activities. A set of features is extracted among the candidate feature set including both traditional features like standard deviation, energy, entropy, and frequency of acceleration and a new type of feature called relative feature. Both subject-independent and subject-dependent experiment methods were evaluated on three kinds of representative classifiers. In the subject-independent experiment among 20 subjects, the decision tree classifier shows the best performance recognizing the finger gestures with an average accuracy rate for 86.92 %. In the subject-dependent experiment, the nearest neighbor classifier got the highest accuracy rate for 97.55 %.

Energy conservation is an important issue in mobile ad hoc networks (MANET), where the terminals are always supplied with limited energy. A new routing protocol is presented according to the study on the influence of low-energy nodes in ad hoc networks. The novel routing protocol (energy sensing routing protocol, ESRP) is based on the energy sensing strategy. Multiple strategy routing and substitute routing are both adopted in this paper. Referring to the level of the residual energy and the situation of energy consumption, different routes are chosen for packets transmission. The local maintenance is adopted, which can reduce packets retransmission effectively when the link breaks. We focus on the network lifetime most in all performances. The evaluation is done in comparison with other routing protocols on NS2 platform, and the simulation results show that this routing protocol can prolong the network lifetime and balance energy consumption effectively.

A switched-capacitor integrator based on dynamic source follower amplifiers has been proposed. Integrator operation has been confirmed and analyzed by assuming 0.18-µm CMOS technology. The integrator can reduce the number of elements considerably compared with conventional ones using operational amplifiers. As a result, the power dissipation of proposed integrator can be reduced to approximately one-eighth that of conventional integrators. The integrator is applied to a second-order ΔΣ modulator, and its successful operation has been confirmed by transistor-level circuit simulation.

This paper proposes a novel blind multiuser detection scheme using CMA (Constant Modulus Algorithm) adaptive array. In the proposed scheme, the received signal is processed in two steps. In the primary step, only one user is captured by the CMA adaptive array, and at the same time, the other users' directions of arrival (DOA) are estimated. In the secondary step, initial weight vectors are set based on the estimated DOAs, and it processes with CMAs again to capture the other users in parallel. Thus, all the users are detected exactly and recovered separately. The Least-squares CMA is applied as an optimization algorithm to improve the performance of the proposed scheme, and the performances using the proposed scheme with linear arrays and circular arrays are discussed in detail. Simulation results are presented to verify the performance of the proposed scheme.

This paper proposes an adaptive antenna using a combination of on-off and CMA algorithms. With the proposed technique, the on-off algorithm is first employed to search for a desired signal direction in which maximum received power is achieved. Then, interference is suppressed by performing CMA. Simulations are conducted according to the potential application of the proposed adaptive antenna. The simulation results show the SINR improvement implying that the proposed adaptive antenna can be applied to microwave RFID systems in order to resolve reader collision. Furthermore, the proposed adaptive antenna is implemented and then experimented. The experimental results verify that the proposed adaptive antenna can reduce interference resulting in the collision problem.

High-power protection switch utilizing a new stub/line selectable configuration is presented. By employing the proposed circuit topology, the insertion loss at receiving mode and the power handling capability at transmitting mode can be independently designed. Therefore, the proposed circuit is able to achieve low insertion loss at receiving mode while keeping high-power performance at transmitting mode. To verify this methodology, MMIC switch has been fabricated in Ka-band. The circuit has achieved the insertion loss of 2 dB, the isolation of 25 dB, and the power handling capability of 40 dBm at 5% bandwidth.

For analog applications, the Metal-Insulator-Metal (MIM) capacitance has to be measured at a much higher resolution than using the conventional methods, i.e. to a sub-femto level. A new robust mismatch measurement technique is proposed, which is more accurate and robust compared to the conventional Floating Gate Capacitance Measurement (FGCM) methods. A capacitance mismatching measurement methodology based on Vs is more stable than that based on Vf because the influence of pre-existing charge in the floating-gate can be cancelled in the slope of ΔVs/ΔVf based on Vs. The accuracy of this method is evaluated through silicon measurement in a 0.13 µm technology. It shows that, compared to the ideal value, the average of the new method are within 0.12% compared to 49.23% in conventional method while the standard deviation is within 0.15%.

A zig-zag Gardner algorithm with parallel architecture is presented in this letter. This algorithm performs timing adjustment in each individual burst independently for high speed wireless burst communication with a short guard. Over sampling data are stored in RAM initially and read forward and backward alternately later. The proposed algorithm has distinct symmetric characteristic in the forward and backward process, which makes the alternate sequences achieve nearly the same effect as a continuous sequence. The performance of the proposed algorithm is very close to the theoretical curve.

This paper presents a circuit that improves supply noise rejection using an active inductor circuit. Compared to the conventional designs, the proposed supply noise suppression circuit has better characteristics such as low current consumption and small die size with noise rejection. The circuit was fabricated using 0.13 µm UMC CMOS technology. The experimental results showed that the supply noise was suppressed by 61% with only an increase in size of 20.0 µm 2.5 µm, and the current consumption was under 2 mA.