In this letter a simplified Jury's table for real polynomials is extended to complex polynomials. Then it is shown that the extended table contains information on the root distribution of complex polynomials with respect to the unit circle in the complex plane. The result given in this letter is distinct from the recent one in that root counting is performed in a different way.

In this paper, we study the average symbol and bit-weight distributions for ensembles of non-binary low-density parity-check codes defined on GF(2p). Moreover, we derive the asymptotic exponential growth rate of the weight distributions in the limit of large codelength. Interestingly, we show that the normalized typical minimum distance does not monotonically increase with the size of the field.

The Medium Access Control (MAC) protocol that uses non-overlapping multiple channels, called the multi-channel MAC protocol, was proposed in order to increase the capacity of ad hoc networks. Since the number of packet interfaces on each node is less than the number of channels in ad hoc networks in general, the node needs to select a suitable channel for data transmission. This means that the multi-channel MAC protocol must be provided with a good channel selection algorithm. In this paper, we design a channel selection algorithm called Conditionally Randomized Channel Selection (CRCS) based on Extended Receiver Directed Transmission (xRDT) protocol that only uses one packet interface. Briefly, CRCS uses the acitve channel for data transmission until the amount of data packets reaches a threshold, at which point it selects one of the available channels other than the active channel. Although CRCS is a very simple channel selection algorithm, by using network simulator we find that CRCS is effective to increase the capacity of ad hoc networks and to keep the load balance of all channels compared to the other channel selection algorithms.

Robust local image features have become crucial components of many state-of-the-art computer vision algorithms. Due to limited hardware resources, computing local features on embedded system is not an easy task. In this paper, we propose an efficient parallel computing framework for speeded-up robust features with an orientation towards multi-DSP based embedded system. We optimize modules in SURF to better utilize the capability of DSP chips. We also design a compact data layout to adapt to the limited memory resource and to increase data access bandwidth. A data-driven barrier and workload balance schemes are presented to synchronize parallel working chips and reduce overall cost. The experiment shows our implementation achieves competitive time efficiency compared with related works.

Power-aware scheduling of periodic tasks in real-time systems has been extensively studied to save energy while still meeting the performance requirement. Many previous studies use the probability information of tasks' execution cycles to assist the scheduling. However, most of these approaches adopt heuristic algorithms to cope with realistic CPU models with discrete frequencies and cannot achieve the globally optimal solution. Sometimes they even show worse results than non-stochastic DVS schemes. This paper presents an optimal DVS scheme for frame-based real-time systems under realistic power models in which the processor provides only a limited number of speeds and no assumption is made on power/frequency relation. A suboptimal DVS scheme is also presented in this paper to work out a solution near enough to the optimal one with only polynomial time expense. Experiment results show that the proposed algorithm can save at most 40% more energy compared with previous ones.

This paper presents a single-chip RF tuner/OFDM demodulator for a mobile digital TV application called “1-segment broadcasting.” To achieve required performances for the single-chip receiver, a tunable technique for a low-noise amplifier (LNA) and spurious suppression techniques are proposed in this paper. Firstly, to receive all channels from 470 MHz to 770 MHz and to relax distortion characteristics of following circuit blocks such as an RF variable-gain amplifier and a mixer, a tunable technique for the LNA is proposed. Then, to improve the sensitivity, spurious signal suppression techniques are also proposed. The single-chip receiver using the proposed techniques is fabricated in 90 nm CMOS technology and total die size is 3.26 mm 3.26 mm. Using the tunable LNA and suppressing undesired spurious signals, the sensitivities of less than -98.6 dBm are achieved for all the channels.

Item response theory (IRT) is widely used for test analyses. Most models of IRT assume that a subject's responses to different items in a test are statistically independent. However, actual situations often violate this assumption. Thus, conditional independence (CI) tests among items given a latent ability variable are needed, but traditional CI tests suffer from biases. This study investigated a latent conditional independence (LCI) test given a latent variable. Results show that the LCI test can detect CI given a latent variable correctly, whereas traditional CI tests often fail to detect CI. Application of the LCI test to mathematics test data revealed that items that share common alternatives might be conditionally dependent.

We describe a parameter estimation method for a target object in an area that sensors monitor. The parameters to be estimated are the perimeter length, size, and parameter determined by the interior angles of the target object. The estimation method does not use sensor location information, only the binary information on whether each sensor detects the target object. First, the sensing area of each sensor is assumed to be line-segment-shaped, which is a model of an infrared distance measurement sensor. Second, based on the analytical results of assuming line-segment-shaped sensing areas, we developed a unified equation that works with general sensing areas and general target-object shapes to estimate the parameters of the target objects. Numerical examples using computer simulation show that our method yields accurate results.

Power-aware X-filling is a preferable approach to avoiding IR-drop-induced yield loss in at-speed scan testing. However, the ability of previous X-filling methods to reduce launch switching activity may be unsatisfactory, due to low effect (insufficient and global-only reduction) and/or low scalability (long CPU time). This paper addresses this reduction quality problem with a novel GA (Genetic Algorithm) based X-filling method, called GA-fill. Its goals are (1) to achieve both effectiveness and scalability in a more balanced manner and (2) to make the reduction effect of launch switching activity more concentrated on critical areas that have higher impact on IR-drop-induced yield loss. Evaluation experiments are being conducted on both benchmark and industrial circuits, and the results have demonstrated the usefulness of GA-fill.

We propose a packet-based inverse multiplexing method to allow scalable network access with a bigger-pipe physical interface. The method is based on aggregation at the physical layer (APL) that fragments an original packet-flow and distributes the fragments among an adequate numbers of physical links or networks. It allows us to share wavelengths and/or bandwidth resources in optical networks. Its technical feasibility at the speed of newly standardized 100 Gb/s Ethernet (100 GbE) is successfully evaluated by implementing the inverse multiplexing logic functions on a prototype board. We demonstrate super-high-definition video streaming and huge file transfer by transmitting 100 GbE MAC frames over multiple 10 GbE physical links via inverse multiplexing.

This letter introduces a blind minimum interference symbol synchronization for orthogonal frequency-division multiplexing (OFDM) systems based on the cyclic prefix (CP). The basic idea of our contribution is to obtain an estimate of the channel-tap powers from the correlation characteristics of the CP. Based on the estimate of the channel-tap powers, a minimum interference metric is proposed. The proposed algorithm has low complexity and can be used to cope with long inter-symbol-interference (ISI) channels with length up to twice the CP length.

Efficient resource allocation for delay-sensitive traffic, such as telephony and video streaming, in Orthogonal Frequency Division Multiple Access (OFDMA) networks is needed to increase system performance. In our system, users try to achieve a low queuing delay and buffer space usage by competing for transmission over the subchannels. We formulate this problem as a bargaining game and use the Nash Bargaining Solution (NBS) to realize a fair and efficient subchannel allocation for the users. Simulation results show performance improvements, with regard to packet dropping and delay distribution, over other algorithms.

In this paper, we show the recent progress of photonic network technologies for the new generation network (NWGN). The NWGN is based on new design concepts that look beyond the next generation network (NGN) and the Internet. The NWGN will maintain the sustainability of our prosperous civilization and help resolve various social issues and problems by the use of information and communication technologies. In order to realize the NWGN, many novel technologies in the physical layer are required, in addition to technologies in the network control layer. Examples of cutting-edge physical layer technologies required to realize the NWGN include a terabit/s/port or greater ultra-wideband optical packet switching system, a modulation-format-free optical packet switching (OPS) node, a hybrid optoelectronic packet switching node, a packet-based reconfigurable optical add/drop multiplexer (ROADM) system, an optical packet and circuit integrated node system, and optical buffering technologies.

The Internet is an extremely convenient network and has become one of the key infrastructures for daily life. However, it suffers from three serious problems; its structure does not suit traffic centralization, its power consumption is rapidly increasing, and its round-trip time (RTT) and delay jitter are large. This paper proposes an extremely energy efficient layer-3 network architecture for the future Internet. It combines the Service Cloud with the Cloud Router and application servers, with the Optical Aggregation Network realized by optical circuit switches, wavelength-converters, and wavelength-multiplexers/demultiplexers. User IP packets are aggregated and transferred through the Optical Aggregation Network to Cloud transparently. The proposed network scheme realizes a network structure well suited to traffic centralization, reduces the power consumption to 1/20-1/30 compared to the existing Internet, reduces the RTT and delay jitter due to its simplicity, and offers easy migration from the existing Internet.

In this paper, we present a 0.18-µm CMOS fully integrated X-band shock wave generator (SWG) with an on-chip dipole antenna and a digitally programmable delay circuit (DPDC) for pulse beam-formability in short-range and hand-held microwave active imaging applications. This chip includes a SWG, a 5-bit DPDC and an on-chip wide-band meandering dipole antenna. By using an integrated transformer, output pulse of the SWG is sent to the on-chip meandering dipole antenna. The SWG operates based on damping conditions to produce a 0.4-V peak-to-peak (p-p) pulse amplitude at the antenna input terminals in HSPICE simulation. The DPDC is designed to adjust delays of shock-wave outputs for the purpose of steering beams in antenna array systems. The wide-band dipole antenna element designed in the meandering shape is located in the top metal of a 5-metal-layer 0.18-µm CMOS chip. By simulating in Momentum of ADS 2009, the minimum value of antenna's return loss, S 11, and antenna's bandwidth (BW) are -19.37 dB and 25.3 GHz, respectively. The measured return loss of a stand-alone integrated meandering dipole is from -26 dB to -10 dB with frequency range of 7.5-12 GHz. In measurements of the SWG with the integrated antenna, by using a 20-dB standard gain horn antenna placed at a 38-mm distance from the chip's surface, a 1.1-mVp-p shock wave with a 9-11-GHz frequency response is received. A measured 3-ps pulse delay resolution is also obtained. These results prove that our proposed circuit is suitable for the purpose of fully integrated pulse beam-forming system.

The excessive memory access required to perform motion compensation when decoding compressed video is one of the main limitations in improving the performance of an H.264/AVC decoder. This paper proposes an H.264/AVC decoder that employs three techniques to reduce external memory access events: efficient distribution of reference frame data, on-chip cache memory, and frame memory recompression. The distribution of reference frame data is optimized to reduce the number of row activations during SDRAM access. The novel cache organization is proposed to simplify tag comparisons and ease the access to consecutive 4×4 blocks. A recompression algorithm is modified to improve compression efficiency by using unused storage space in neighboring blocks as well as the correlation with the neighboring pixels stored in the cache. Experimental results show that the three techniques together reduce external memory access time by an average of 90%, which is 16% better than the improvements achieved by previous work. Efficiency of the frame memory recompression algorithm is improved with a 32×32 cache, resulting in a PSNR improvement of 0.371 dB. The H.264/AVC decoder with the three techniques is fabricated and implemented as an ASIC using 0.18 µm technology.

Dicode partial response signaling system over inductively-coupled channel has been developed to achieve higher data rate than self-resonant frequencies of inductors. The developed system operates at five times higher data rates than conventional systems with the same inductor. A current-mode equalization in the transmitter designed in a 90-nm CMOS successfully reshapes waveforms to obtain dicode signals at the receiver. For a 5-Gb/s signaling through the coupled inductors with a 120-µm diameter and a 120-µm distance, 20-mV eye opening was observed. The power consumption value of the transmitter was 58 mW at the 5-Gb/s operation.

A low-loss ultra-wide band (UWB) filter is presented, which uses miniaturized parallel coupled line along with an standard printed circuit board (PCB) technology. By analyzing even- and odd-mode impedances (in comparison with conventional parallel coupled lines) of miniaturized parallel coupled line, this structure provides tight coupling, thus, relaxing the requirements on physical dimensions width and spacing when designing broadband filters. A bandpass filter for Mode 1 (the first 3 sub-bands) in the 3.1-5 GHz band for Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) UWB is realized and compared with a conventional parallel coupled line filter. The experimental results show as much as 0.9 dB insertion loss improvement over the conventional counterpart.

A resource allocation scheme for multi-access MIMO-OFDM systems in uplink was developed to improve power and spectrum efficiency in the frequency and the space domains [1]. The scheme requires a multi-user detector in the receiver and assumes identical spatial crosscorrelation across all subcarriers for any pair of spatially separable users. However, the multi-user detection device may not exist in the receiver and the identical spatial crosscorrelation assumption may not be valid in some operational scenarios. The paper develops a scheme to remedy these problems for multi-access MIMO-OFDM systems without using multi-user detection techniques and the assumption. The proposed scheme aims at minimizing the total user transmit power while satisfying the required data rate, the maximum transmit power constraint, and the bit error rate of each user. The simulation results are presented to demonstrate the efficacy of the proposed algorithm.

Bandwidth is an extremely valuable and scarce resource in multimedia networks. Therefore, efficient bandwidth management is necessary in order to provide high Quality of Service (QoS) to users. In this paper, a new QoS-aware bandwidth allocation algorithm is proposed for the efficient use of available bandwidth. By using the multi-objective optimization technique and Talmud allocation rule, the bandwidth is adaptively controlled to maximize network efficiency while ensuring QoS provisioning. In addition, we adopt the online feedback strategy to dynamically respond to current network conditions. With a simulation study, we demonstrate that the proposed algorithm can adaptively approximate an optimized solution under widely diverse traffic load intensities.