Multiresolution coding techniques for digital television: A review

Multiresolution decompositions for video coding are reviewed. Both nonrecursive and recursive coding schemes are considered. In nonrecursive schemes, it is shown that pyramid structures have certain advantages over subband or wavelet techniques, and a specific spatiotemporal pyramid coding of HDTV is discussed in some detail. It is shown that recursive, DPCM like schemes will incur a slight loss of optimality due to a restricted form of prediction if multiresolution decomposition with compatible decoding is required. Compatibility and transmission issues are also discussed. Multiresolution transmission for digital broadcast TV is introduced. This, when combined with multiresolution source coding, achieves spectrum efficiency, robustness and graceful degradation under channel impairments.Invited PaperWork supported in part by the National Science Foundation under grants ECD-88-11111, MIP-90-14189 and Bell Communications Research.Work supported by the National Science Foundation under grants ECD-88-11111. K.M. Uz is now with David Sarnoff Research Center in Princeton, NJ 08543.     

The single nerve fiber action potential and the filter bank--a modeling approach

Single fiber action potentials (SFAPs) from peripheral nerves, such as recorded with cuff electrodes, can be modelled as the convolution of a source current and a weight function that describes the recording electrodes and the surrounding medium. It is shown that for cuff electrodes, the weight function is linearly scaled with the action potential (AP) velocity and that it is, therefore, possible to implement a model of the recorded SFAPs based on a wavelet multiresolution technique (filterbank), where the wavelet scale is proportional to the AP velocity. The model resulted in single fiber action potentials matching the results from other models with a goodness of fit exceeding 0.99. This formulation of the SFAP may serve as a basis for model-based wavelet analysis and for advanced cuff design.     

Trade-offs in the OTA-based analog filter design

Operational transconductance amplifiers (OTAs) are widely used in the design of electronically tunable circuits. However, electronic tunability ranges of the OTA based filters are restricted by the limited bandwidth of the transconductance gain of the OTA. Furthermore, stability conditions and the linearity of the OTA which depends on the control current restrict the tunability. In this paper, some trade-offs in the electronically tunable filters are investigated. In addition, the tunability ranges of some first and second order OTA-C and OTA-RC filters are comparatively examined. Moreover, an OTA-C all-pass filter circuit is presented. SPICE simulations are performed and stability analyses are given for both of the OTA-C and OTA-RC filters. Operation of the presented all-pass filter is verified experimentally.     

Appraisal of self, social environment, and state authority as a possible mediator of posttraumatic stress disorder in tortured political activists.

This study examined appraisal of self and others, as measured by semantic differential ratings of Police, State, Society, Family, Friend, Myself as a Man/Woman, and Myself as a Political Person, in 55 tortured political activists in Turkey, 55 nontortured political activists, and 55 nontortured, politically noninvolved controls. There were no remarkable differences between tortured and nontortured political activists; both groups differed from controls in having a more negative appraisal of the police and the state and stronger perceptions of danger, mistrust, and injustice in relation to state authority. Lack of beliefs concerning a "benevolent state" may have protected the survivors from the traumatic effects of state-perpetrated torture. Further research into the possible protective role of belief systems in posttraumatic stress disorder is needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance of a Tied-Arch Reinforced Concrete Railway Bridge: Rating, Safety Assessment, and Bond Length Evaluation

This study presents investigations regarding visual inspection, dynamic testing, and finite-element modeling of an approximately 80-year old reinforced concrete tied-arch railway bridge that is still in service in Turkey. Investigations were conducted as part of a systematic periodic inspection along Ankara-Zonguldak railway line. The bridge is subject to heavy freight trains with increasing axle loads. Field tests such as material tests and dynamic tests were used to calibrate the finite-element model of the bridge. Detailed information regarding testing and model updating procedure is given. Based on test results, computer model was refined. The calibrated model of the bridge structure was then used for structural assessment and evaluation. Despite sufficient overall safety, local details were found to be problematic. Due to insufficient bond length in hanger-to-arch connection, a strengthening scheme using steel channel sections was proposed.     

Neural Network Based Receiver for Multiuser Detection in MC-CDMA Systems

In this paper, we present a multiuser detection technique based on artificial neural network (NN) for synchronous multicarrier code division multiple access systems over Rayleigh fading channels. To test the robustness of the proposed receiver, also the effect of power control problem is studied with a comparative manner. Bit error rate (BER) performance of the NN based receiver is compared with the single user bound and conventional receivers. Although the BER performance of the conventional receiver degrades as the number of the users and power level differences among the users increase, as a decision structure, neural network based receiver gives closer BER performance to the single user bound.     

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.     

Parasitic compensation in CCI-based circuits for reduced power consumption

In this paper, the compensation advantage of the first-generation current conveyor (CCI) over the second-generation current conveyor (CCII) in tunable circuits is shown. For this purpose, a new floating frequency dependent negative resistor (FDNR) simulator using three CCIs is presented and employed in a third-order high-pass filter. The compensation feature of the CCI is shown for the proposed high-pass filter. As a second example, the presented compensation method is tested in a second-order band-pass filter constructed with two CCIs. Applying the proposed compensation technique, the CCI-based circuits can operate in lower biasing currents, which result in lower power consumption.     

Process control at the sealing line during sheet metal hydroforming

Sheet metal hydroforming is a deep drawing process that uses a pressure medium for load transmission. The process is mainly influenced by the control of the blank holder force and the fluid pressure. This report describes investigations of a newly developed process-control system. Process variables can be controlled by the sealing state of the tool. The detection is performed by a CCD-camera system that allows the continuous recording of occurring leakages. Different control strategies can be used to control the multiple process parameters. This paper describes the performance and the limits of the aforementioned technology.     

Enhancing electrochromic properties of polypyrrole by silsesquioxane nanocages

A new monomer, octa(thiophenephenyl)silsesquioxane (OThiophenePS) was synthesized via click chemistry. The chemical structure of OThiophenePS was characterized by nuclear magnetic resonance (¹H NMR) and Fourier transform infrared (FT-IR) spectroscopies. Electrochemical polymerization of pyrrole with OThiophenePS was performed resulting in polypyrrole-attached, polyhedral oligomeric silsesquioxane (OPS–PPy). The spectroelectrochemical studies show that the electrochromic properties of (OPS–PPy) are superior to those of polypyrrole (PPy). This great improvement can be attributed to the more accessible doping sites and the facile ion movement during the redox switching brought by the loose packing of the PPy chains.