Stochastic convergence analysis of recursive successive over-relaxation algorithm in adaptive filtering

A stochastic convergence analysis of the parameter vector estimation obtained by the recursive successive over-relaxation (RSOR) algorithm is performed in mean sense and mean-square sense. Also, excess of mean-square error and misadjustment analysis of the RSOR algorithm is presented. These results are verified by ensemble-averaged computer simulations. Furthermore, the performance of the RSOR algorithm is examined using a system identification example and compared with other widely used adaptive algorithms. Computer simulations show that the RSOR algorithm has better convergence rate than the widely used gradient-based algorithms and gives comparable results obtained by the recursive least-squares RLS algorithm.     

Sharpening filter for false color imaging of dual-energy X-ray scans

Dual-energy X-ray imaging has a vast range of application in security. Luggage inspection is an essential process for an airplane or court house security as well as securing mass events. An image of a content of some package may help to figure out if there is any dangerous object inside and avoid possibly threatening situation. As the raw X-ray images are not always easy to analyze and interpret, some image processing methods like an object detection, a frequency resolution increase or a pseudocoloring are being used. Since color can be a powerful tool to improve the usefulness of an information display, we propose pseudocoloring improvement by modifying material-based approach with edge detection to fill and sharpen color layers over the image making it easier to read and analyze. We demonstrate the effectiveness of the methods using real data, acquired from a professional dual-energy X-ray scanner.     

Analysis of fractal inter frame video coding using parallel approach

Digital video has many applications varying from telecommunications to broadcasting and so on. Video compression techniques have evolved over the past two decades with prominent technique being developed using fractal. However, this technique was not so popular because of its computationally intensive nature. This paper proposes an inter frame video compression technique, which consists of a combination of a block matching using fractal compression. The proposed algorithm is implemented on CUDA-enabled GPU which significantly reduces the encoding time of the video and provides a very high compression ratio with reasonable quality of the decoded video. Extensive simulations were carried out to analyze the performance of the proposed algorithm.     

A fast method for moving object detection in video surveillance image

Moving object detection and extraction are widely used in video surveillance and image processing. In this paper, we present a fast method for moving object detection. We use weights of the Gaussian distribution as decision factors, update parameters of the Gaussian mixture model if its values are smaller than that of those not belonging to the background; otherwise, no updates are done. It improves the existing methods by updating the Gaussian mixture model selectively. Experimental results on various scenes of video surveillance show that computation time of the proposed method is reduced.     

DSTBC experimental research on UV communication system

Diversity gain can be obtained by applying the space–time block code (STBC) technology to ultraviolet (UV) communication. However, some STBCs, for example, the Alamouti code, quite depend on the acquisition of UV channel state information (CSI) because the accuracy of the obtained CSI influences the quality of the received signal and finally influences the system performance. Yet it is not easy to precisely obtain CSI, and this will affect the validity of some STBC decoding. To solve this problem, this paper tends to study the application of differential space–time block code (DSTBC) technology in the UV communication system. The validity with the exact diversity gain is verified with simulation and experimental results. The processes of the transmitters and receivers in \(2\times 2\) DSTBC are analyzed, and the different UV system performances in different communication situations are acquired. The algorithm complexity of DSTBC is compared with that of Alamouti code. The conclusion then is that the advantage of the DSTBC scheme with no requirement of obtaining real-time CSI is found in the fast time-varying and quick decaying UV channel.     

JMAWR: joint optimization of monitoring trail allocation and wavelength routing with limited monitoring resources

In all-optical networks, monitoring trail (m-trail) has long been proposed as an effective way for link failure localization. Previous works tried to minimize the number of used m-trails for localizing network-wide single link failures, and they all supposed that the monitoring resources were enough. However, failures are rare events and the traffic demand is increasing rapidly. The dedicated wavelengths for m-trails cannot be used to transmit data traffic, and some traffic demand may not be served during the peak period. Considering the operators prefer to serve customers’ demand as much as possible, if the resources allocated for m-trails are limited, more traffic will be carried. In this paper, we focus on the scenario where there are not enough resources for allocating m-trails. In this scenario, as only part of single link failures can be unambiguously localized, we aim to monitor the most valuable links, which carry more traffic demand, and minimize the maximum number of used wavelengths for traffic demand on the links which cannot be unambiguously localized. As we can also control the wavelength routing for traffic demand, we try to jointly optimize the m-trail allocation and wavelength routing. We first formulate this joint optimization problem as a mathematical model and present concrete analyses on this model. According to these analyses, a joint m-trail allocation and wavelength routing (JMAWR) heuristic algorithm is proposed based on graph-constrained group testing. Simulation results show that JMAWR outperforms the state-of-the-art m-trail allocation algorithm by up to 88.46% improvement in terms of maximum number of used wavelengths for traffic demand on links which cannot be unambiguously localized.     

CMOS harmonic upconverter with power management of $$2{\bf nd}$$ harmonic for wideband short-range communications

The design and simulation of a 2nd harmonic based upconverter is introduced. With the proposed upconverter, it is possible to reach a good noise figure with power and area reduction. The design of the circuit was made with the UMC \(0.18\,\upmu \hbox {m}\) Mixed Mode/RF CMOS technology. However, the design methodology can be extended to a different CMOS process. According to the performance exhibited by the purposed mixer, it may be useful in wideband short-range communication technologies, such as certified wireless USB.     

A 1.1-mW 10-bit 50-MSample/s hybrid two-step ADC in 0.13-µm CMOS technology

This paper presents a hybrid two-step analog-to-digital converter (ADC) that employs a successive approximation register (SAR) ADC and a time-to-digital converter (TDC)-based ADC as coarse and fine converters, respectively. By exploiting the respective advantages of the SAR and TDC architectures, the two-step ADC is realized without a high-gain amplifier for high linearity of a multiplying digital-to-analog converter. Thus, the proposed architecture can implement a low-power ADC without compromising operational speed. In addition, two digital error corrections are used to compensate for TDC error and the final ADC output, respectively. A 10-bit 50 MS/s ADC is fabricated in a 0.13-μm complementary metal–oxide–semiconductor process and occupies a 0.12-mm² die area. Furthermore, it consumes only 1.1 mW and achieves a signal-to-noise distortion ratio and spurious-free dynamic range of 53.67 and 60 dB, respectively, resulting in a 53.7 fJ/conversion-step at a 25-MHz full-scale input.     

FVF LDO regulator with dual dynamic-load composite gain stage

A low-voltage output-capacitorless low-dropout regulator using dual dynamic-load composite gain stage for flipped voltage follower topology is presented. It also incorporates a delay discharge circuit which aims to reduce the long discharge time arising from the large capacitive load, thus achieving the overshoot time reduction and sustaining fast transient characteristic when driving low-power digital system with internal heavy capacitive load requirement. The regulator can support a minimum of 0.75 V input voltage with 0.5 V output voltage. It consumes 49.4 µA whilst maintaining the stability for a capacitance load range from 470 pF to 10 nF. For a current load transient from 0 to 10 mA with 200 ps edge time, the settling time is 0.38 µs for the load capacitance of 3 nF. The obtained transient figure-of-merit is 0.42 mV. This transient metric outperforms the representative prior-art reported works.     

A 90–96 GHz CMOS down-conversion mixer with high conversion gain and excellent LO–RF isolation

A 90–96 GHz down-conversion mixer for 94 GHz image radar sensors using standard 90 nm CMOS technology is reported. RF negative resistance compensation technique, i.e. NMOS LC-oscillator-based RF transconductance (GM) stage load, is used to increase the output impedance and suppress the feedback capacitance C_gd of RF GM stage. Hence, conversion gain (CG), noise figure (NF) and LO–RF isolation of the mixer can be enhanced. The mixer consumes 15 mW and achieves excellent RF-port input reflection coefficient of ?10 to ?36.4 dB for frequencies of 85–105 GHz. The corresponding -10 dB input matching bandwidth is 20 GHz. In addition, for frequencies of 90–96 GHz, the mixer achieves CG of 6.3–9 dB (the corresponding 3-dB CG bandwidth is greater than 6 GHz) and LO–RF isolation of 40–45.1 dB, one of the best CG and LO–RF isolation results ever reported for a down-conversion mixer with operation frequency around 94 GHz. Furthermore, the mixer achieves an excellent input third-order intercept point of 1 dBm at 94 GHz. These results demonstrate the proposed down-conversion mixer architecture is very promising for 94 GHz image radar sensors.