Filter banks for improved LCD motion

In the past several years much attention has been placed on improving the motion picture quality of liquid crystal displays (LCDs). One pervasive problem is motion blur which occurs due to the inherent sample-and-hold nature of LCD image formation. In this work, we take a signal processing approach to motion blur reduction by pre-processing the data before it is sent to the display. We develop a two-channel non-perfect reconstruction filter bank that is able to reduce the amount of perceivable motion blur. In addition, as in similar works, we discriminate between different regions of the scene and weight the application of the algorithm based on their susceptibility to motion blur. Perceptual tests indicate that our algorithm reduces the amount of perceivable motion blur on LCDs.     

正确选择电源管理方案，提升系统性能并延长电池寿命

有了无线技术,用户就真正实现了"网络随行".然而无线设备无法长时间连接固定电源,因此如果仅靠电池供电的话,很快就能把电池电量消耗完.无论采用何种化学技术,电池都只能存储有限的电量,当电量耗尽时均需要替换或充电.加强对电源管理问题的重视可有助于延长电池的寿命.基站等一些不用依靠电池的无线系统必须在兼顾能源效率的前提下,才能实现高性能指标.     

Cross-Layer Design for MRT Systems with Channel Estimation Error and Feedback Delay

Multiple-input multiple-output (MIMO) beamforming is a joint spatial diversity scheme applied in frequency selective channels to enhance system performance. In uplink transmission, the impact of correlation of path gains and mutual coupling at transmitters cannot be ignored because of the size constraint on mobile terminals. In this paper, an iterative MIMO beamforming algorithm with maximal ratio transmit-maximal ratio combining (MRT-MRC) strategy is presented to improve the output signal-to-noise and interference ratio in the presence of spatial correlation and mutual coupling between transmit elements. To reduce the complexity of systems, we also propose an equal gain transmit-maximal ratio combining (EGT-MRC) scheme. In contrast to MRT-MRC scheme, this algorithm can provide better system performance. The results of numerical simulations verify the advantages of this scheme.     

Transmission of 160-Gb/s Modified Manchester modulation over WDM system

The paper examines the performance of Modified Manchester (MM) modulation scheme over wavelength division multiplexing (WDM) in high-speed optical communication links. The MM as a new modulation technique has a narrow spectral width compared to conventional Manchester coding, which allows its implementation in WDM systems beneficial. In this study, the performance characteristics of MM and conventional Manchester modulation formats are assessed in WDM system at 10 Gb/s bitrate for each channel, for the least allowable channel spacing as well as tolerance to chromatic dispersion (CD). It is revealed from the results of simulation that MM performs meaningfully well in comparison with conventional Manchester in terms of tolerance against narrow optical filtering, spectral efficiency, which is improved by 32% and CD tolerance, which is improved by +100 ps/nm. Sixteen wavelength channels (16 × 10 Gb/s) are modulated to provide 160 Gb/s data capacity, which was transmitted successfully over 224 km standard single mode fibre (SSMF) using MM while the conventional Manchester only covered about 157 km.     

The chemical and structural origin of efficient p-type doping in P3HT

We investigate the chemical and structural properties of solution-processed thin films of P3HT blended with p-type dopant F4TCNQ. The maximum in-plane electrical conductivity of doped films is observed at a molar doping fraction of 0.17, in agreement with the binding mechanism of F4TCNQ:P3HT complexes. Through the use of X-ray diffraction, a previously unreported crystalline phase is observed for P3HT films doped above a critical threshold concentration. This crystalline phase involves the incorporation of F4TCNQ molecules into ordered polymer regions and ultimately improves charge dissociation, leading to higher carrier density in thin film. Finally, optical absorption and X-ray diffraction reveal that the chemical state of P3HT in solution has a dramatic impact on the electrical and structural properties of the blended films.     

On security of wireless sensor networks: a data authentication protocol using digital signature

Guaranteeing end-to-end data security in wireless sensor networks (WSNs) is important and has drawn much attention of researchers over past years. Because an attacker may take control of compromised sensor nodes to inject bogus reports into WSNs, enhancing data authenticity becomes a necessary issue in WSNs. Unlike PCREF (Yang et al. in IEEE Trans Comput 64(1):4–18, 2015) (LEDS, Ren et al. in IEEE Trans Mobile Comput 7(5):585–598, 2008), digital signature rather than message authentication polynomials (message authentication codes) is adopted by our protocol in en-route filtering. Keeping the advantages of clusters in PCREF and overcoming the drawbacks in LEDS, an enhanced and efficient cluster-based security protocol is proposed in this paper. The proposed protocol can guarantee end-to-end data authentication with the aid of digital signature and exhibits its effectiveness and efficiency through security analysis and performance analysis. Our analytical results show that the proposed protocol significantly outperforms the closely related protocols in the literature in term of security strength and protocol overhead.     

A comparison between high-pass and low-pass \Updelta\Upsigma modulators

In this paper, high-pass (HP) $\Updelta\Upsigma$ modulators are compared against the traditional low-pass (LP) $\Updelta\Upsigma$ modulators. The objective of this comparison is to point out the advantages and drawbacks of the two modulators thereby allowing choosing the most suited for a given application. The metrics of comparison are the noise floor, power consumption, area and the effect of the non-idealities of all the basic blocks (i.e., operational transconductance amplifier, quantizer, switches and clocks). The comparative analysis shows that HP modulators are more suited for narrow band applications because of their immunity against DC-offset and flicker noise. For medium and wide band applications, LP modulators are preferred because of their higher robustness against switch imperfections and clock jitter.     

Different Directions of Switching of Chromium Oxide Thin Films

We have investigated the switching behavior of as-deposited CrO _x and post-annealed CrO _y films by use of a variety of electrodes (top electrode Ag, Ti; bottom electrode Pt, fluorine tin oxide (FTO)). Resistance switching is highly dependent on electrode material and post-annealing treatment. Among Pt devices, I–V hysteresis was observed for the Ag/CrO _x /Pt device only; no resistance switching was observed for Ag/CrO _y /Pt, Ti/CrO _x /Pt, and Ti/CrO _y /Pt devices. Among FTO devices, I–V hysteresis was observed for the Ag/CrO _x /FTO device whereas I–V hysteresis with the opposite switching direction was observed for Ag/CrO _y /FTO, Ti/CrO _x /FTO, and Ti/CrO _y /FTO devices. The direction of switching depends not only on electrode material but also on post-annealing treatment, which affects the density of grain boundaries. Thus, the density of grain boundaries determines the type of charge carrier involved in the switching process. For as-deposited CrO _x films with a high density of grain boundaries Ag filament paths mediated by electrochemical redox reaction were observed, irrespective of bottom electrode material (Pt or FTO). Post-annealed CrO _y films with a low density of grain boundaries suppressed electrochemical redox reaction in the Ag/CrO _y /Pt device but promoted short-range movement of O^2? ions through the bottom interface, resulting in resistance switching in the Ag/CrO _y /FTO device. Electrochemical redox reaction-controlled resistance switching occurred solely in oxides with a high density of grain boundaries or dislocations.     

From trips to telcos — next generation service portals

A number of multi-billion dollar businesses (for example Dell, Amazon, Expedia and Google) have been built on top of Web portals that provide customers with a differentiating experience. How do these portals achieve this, and what lessons can BT learn? In this paper we describe technology that supports the development of portals which extend and improve the customer’s experience of interacting with a company by breaking away from the direct manipulation metaphor. We illustrate the approach with a case study and describe the results of the work we have done in terms of the limitations and capabilities of the approach developed.     

Adaptive encoding of zoomable video streams based on user access pattern

Zoomable video allows users to selectively zoom and pan into regions of interest within the video for viewing at higher resolutions. Such interaction requires dynamic cropping of RoIs on the source video. We have previously explored two different ways of encoding and transmitting video to support dynamic RoI cropping: (i) Monolithic streaming uses a standard video encoder to encode the video. When an RoI is requested, the bits belonging to the RoI along with other bits required to decode the RoIs (due to encoding dependencies) are transmitted. (ii) Tile streaming divides regions in the standard video into rectangular tiles that are encoded independently. The tiles that intersect with a requested RoI are transmitted. In this paper, we consider how the bandwidth needed to transmit the RoIs can be reduced by carefully encoding the source video for each of the two encoding schemes. The goal is to support bandwidth efficient compressed domain RoI cropping in the context of virtual zoom and pan by tuning encoder parameters. Our key idea is to exploit user access patterns to the RoIs, and encode different regions of the video with different encoding parameters based on the popularity of the region. We show that our encoding method can reduce the expected bandwidth by up to 43% in the test video sequence which we have used.