A new look at dual-hop relaying: Performance limits with hardware impairments

Physical transceivers have hardware impairments that create distortions which degrade the performance of communication systems. The vast majority of technical contributions in the area of relaying neglect hardware impairments and, thus, assume ideal hardware. Such approximations make sense in low-rate systems, but can lead to very misleading results when analyzing future high-rate systems. This paper quantifies the impact of hardware impairments on dual-hop relaying, for both amplify-and-forward and decode-and-forward protocols. The outage probability (OP) in these practical scenarios is a function of the effective end-to-end signal-to-noise-and-distortion ratio (SNDR). This paper derives new closed-form expressions for the exact and asymptotic OPs, accounting for hardware impairments at the source, relay, and destination. A similar analysis for the ergodic capacity is also pursued, resulting in new upper bounds. We assume that both hops are subject to independent but non-identically distributed Nakagami-m fading. This paper validates that the performance loss is small at low rates, but otherwise can be very substantial. In particular, it is proved that for high signal-to-noise ratio (SNR), the end-to-end SNDR converges to a deterministic constant, coined the SNDR ceiling, which is inversely proportional to the level of impairments. This stands in contrast to the ideal hardware case in which the end-to-end SNDR grows without bound in the high-SNR regime. Finally, we provide fundamental design guidelines for selecting hardware that satisfies the requirements of a practical relaying system.

NSUN4 Is a Dual Function Mitochondrial Protein Required for Both Methylation of 12S rRNA and Coordination of Mitoribosomal Assembly

Biogenesis of mammalian mitochondrial ribosomes requires a concerted maturation of both the small (SSU) and large subunit (LSU). We demonstrate here that the m(5)C methyltransferase NSUN4, which forms a complex with MTERF4, is essential in mitochondrial ribosomal biogenesis as mitochondrial translation is abolished in conditional Nsun4 mouse knockouts. Deep sequencing of bisulfite-treated RNA shows that NSUN4 methylates cytosine 911 in 12S rRNA (m5C911) of the SSU. Surprisingly, NSUN4 does not need MTERF4 to generate this modification. Instead, the NSUN4/MTERF4 complex is required to assemble the SSU and LSU to form a monosome. NSUN4 is thus a dual function protein, which on the one hand is needed for 12S rRNA methylation and, on the other hand interacts with MTERF4 to facilitate monosome assembly. The presented data suggest that NSUN4 has a key role in controlling a final step in ribosome biogenesis to ensure that only the mature SSU and LSU are assembled.

Improved APF strategies for dual-arm local motion planning

Manipulator motion planning is a classic problem in robotics, with a number of complete solutions available for their motion in controlled (industrial) environments. Owing to recent technological advances in the field of robotics, there has been a significant development of more complex robots with high-fidelity sensors and more computational power. One such example has been a rise in the production of humanoid robots equipped with dual-arm manipulators which require complex motion planning algorithms. Also, the technological advances have resulted in a shift from using manipulators in strictly controlled environments, to investigating the deployment of manipulators in dynamic or unknown environments. As a result, a greater emphasis has been put on the development of local motion planners, which can provide real-time solutions to these problems. Artificial Potential Fields (APFs) is one such popular local motion planning technique, which can be applied to manipulator motion planning, however, the basic algorithm is severely prone to local minima problems. Here, two modified APF-based strategies for solving the dual-arm motion planning task in unknown environments are proposed. Both techniques make use of configuration sampling and subgoal selection to assist the APFs in avoiding these local minima scenarios. Extensive simulation results are presented to validate the efficacy of the proposed methodology.

Integrating intrinsic and global kinetics as a dual kinetic model for automotive catalysis

The majority of the kinetic models employed in catalytic after-treatment of exhaust emissions use a global kinetic approach owing to the simplicity because one expression can account for all the steps in a reaction. The major drawback of this approach is the limited predictive capabilities of the models. The intrinsic kinetic approach offers much more information about the processes occurring within the catalytic converter; however, it is significantly more complex and time consuming to develop. In the present work, a methodology which allows accessing a model that combines the simplicity of the global kinetic approach and the accuracy of the intrinsic kinetic approach is reported. To assess the performance of this new approach, the oxidation of carbon monoxide in the presence of nitric oxide as well as a driving cycle was investigated. The modelling of carbon monoxide oxidation with oxygen which utilised the intrinsic kinetic approach with the global kinetic approach was used for the carbon monoxide + nitric oxide reaction (and all remaining reactions for the driving cycle). The comparison of the model results for the dual intrinsic + global kinetic approach with the experimental data obtained for both the reactor and the driving cycle indicate that the dual approach is promising with results significantly better than those obtained with only the global kinetics approach.

A Novel Dual-band Printed Diversity Antenna for Mobile Terminals

A novel dual-band printed diversity antenna is proposed and studied. The antenna, which consists of two back-to- back monopoles with symmetric configuration, is printed on a printed circuit board. The effects of some important parameters of the proposed antenna are deeply studied and the design methodology is given. A prototype of the proposed antenna operating at UMTS (1920-2170 MHz) and 2.4-GHz WLAN (2400-2484 MHz) bands is provided to demonstrate the usability of the methodology in dual-band diversity antenna for mobile terminals. In the above two bands, the isolations of the prototype are larger than 13 dB and 16 dB, respectively. The measured radiation patterns of the two monopoles in general cover complementary space regions. The diversity performance is also evaluated by calculating the envelope correlation coefficient, the mean effective gains of the antenna elements and the diversity gain. It is proved that the proposed antenna can provide spatial and pattern diversity to combat multipath fading.

IRIDE:Interdisciplinary research infrastructure based on dual electron linacs and lasers

This paper describes the scientific aims and potentials as well as the preliminary technical design of IRIDE, an innovative tool for multi-disciplinary investigations in a wide field of scientific, technological and industrial applications. IRIDE will be a high intensity "particles factory", based on a combination of high duty cycle radio-frequency superconducting electron linacs and of high energy lasers. Conceived to provide unique research possibilities for particle physics, for condensed matter physics, chemistry and material science, for structural biology and industrial applications, IRIDE will open completely new research possibilities and advance our knowledge in many branches of science and technology. IRIDE is also supposed to be realized in subsequent stages of development depending on the assigned priorities. © 2013 Elsevier B.V.

Active singly and dual polarised interwoven spiral frequency selective surfaces

Reconfigurable bi-state interwoven spiral FSSs are explored in this work. Their switching capability is realized by pin diodes that enable the change of the electromagnetic response between transparent and reflecting modes at the specified frequencies in both singly and dual polarised unit cell configurations. The proposed topologies are single layer FSS with their elements acting also as dc current carrying conductors supplying the bias signal for switching pin diodes between the on and off states, thus avoiding the need of external bias lines that can cause parasitic resonances and affect the response at oblique incidence. The presented simulation results show that such active FSSs have potentially good isolation between the transmission and reflection states, while retaining the substantially subwavelength response of the unit cell with large fractional bandwidths (FBWs) inherent to the original passive FSSs.

Global Production, CSR and Human Rights: The Courts of Public Opinion and the Social License to Operate

This paper takes at its starting point the responsibility placed upon corporations by the United Nations’ Protect, Respect and Remedy Framework as elaborated upon by the Guiding Principles on Business and Human Rights to respect human rights. The overt pragmatism and knowledge of the complex business relationships that are embedded in global production led John Ruggie, the author of the Framework, to adopt a structure for the relationship between human rights and business that built on the existing practices of Corporate Social Responsibility (CSR). His intention was that these practices should be developed to embrace respect for human rights by exhorting corporations to move from “the era of declaratory CSR” to showing a demonstrable policy commitment to respect for human rights. The prime motivation for corporations to do this was, according to Ruggie, because the responsibility to respect was one that would be guarded and judged by the “courts of public opinion” as part of the social expectations imposed upon corporations or to put it another way as a condition of a corporation’s social license to operate.
This article sets out the background context to the Framework and examines the structures that it puts forward. In its third and final section the article looks at how the Framework requires a corporation’s social license to be assembled and how and by whom that social license will be judged. The success or failure of the Framework in persuading corporations to respect human rights is tied to whether “the courts of public opinion” can use their “naming and shaming power” effectively.

Coherent spectral enhancement of carrier-envelope-phase stable continua with dual-gas high harmonic generation

Attosecond science is enabled by the ability to convert femtosecond near-infrared laser light into coherent harmonics in the extreme ultraviolet spectral range. While attosecond sources have been utilized in experiments that have not demanded high intensities, substantially higher photon flux would provide a natural link to the next significant experimental breakthrough. Numerical simulations of dual-gas high harmonic generation indicate that the output in the cutoff spectral region can be selectively enhanced without disturbing the single-atom gating mechanism. Here, we summarize the results of these simulations and present first experimental findings to support these predictions. (c) 2012 Optical Society of America

Price Discovery in the Dual-Platform US Treasury Market

Inter-dealer trading in US Treasury securities is almost equally divided between two electronic trading platforms that have only slight differences in terms of their relative liquidity and transparency. BrokerTec is more active in the trading of 2-, 5-, and 10-year T-notes while eSpeed has more active trading in the 30-year bond. Over the period studied, eSpeed provides a more pre-trade transparent platform than BrokerTec. We examine the contribution to ‘price discovery’ of activity in the two platforms using high frequency data. We find that price discovery does not derive equally from the two platforms and that the shares vary across term to maturity. This can be traced to differential trading activities and transparency of the two platforms.

Dual functional ionic liquids as antimicrobials and plasticisers for medical grade PVCs

Two ionic liquids, 1-ethylpyridinium docusate (IL1) and tri-n-butyl(2-hydroxyethyl)phosphonium docusate (IL2), were designed and synthesized with the explicit intention of imparting a combination of plasticization and antimicrobial efficacy when incorporated into medical grade poly(vinyl chloride)s (PVCs). The glass transition (T-g) of PVC can be reduced by >20 degrees C on addition of 15 wt% IL2. Both IL1 and IL2 leached to varying extents from the base PVC resins rendering the surface of the PVCs hydrophilic. The antimicrobial activity of both ILs is related to the presence and concentration of both cationic and anionic component of the ILs leached from the PVC and inversely proportional to the extent of PVC gelation. Blends of the PVCs with IL1 displayed antibacterial activity against almost all Gram-positive bacteria tested, including coagulase-negative Staphylococci (CoNS) and methicillin-resistant Staphylococcus aureus (MRSA), but not with IL2 at low concentration in contrast to our previous study when high concentrations of IL2 were used. The more hydrophilic IL1 when added to PVC retards biofilm formation.