Statistical analysis and modeling of the temperature-dependent sleep behavior of drosophila

The sleep behavior of drosophila is analyzed under different temperatures. The activity per minute of the flies is recorded automatically. Sleep for a fruit fly is defined as the periods without any activity and longer than 5 minutes. Several parameters such as total sleep time, circadian sleep profile, quality of sleep are analyzed. The sleep behaviors are significantly different for flies at different temperature. Interestingly, the durations of daytime sleep periods show a common scale-free power law distribution. We propose a stochastic model to simulate the activities of the population of neurons which regulate the dynamics of sleep–wake process to explain the distribution of daytime sleep.     

Spindle position regulation for wind power generators

The three-time-scale plant model of a wind power generator, including a wind turbine, a flexible vertical shaft, a variable inertia flywheel (VIF) module, an active magnetic bearing (AMB) unit and the applied wind sequence, is constructed. In order to make the wind power generator be still able to operate as the spindle speed exceeds its rated speed, the VIF is equipped so that the spindle speed can be appropriately slowed down once any stronger wind field is exerted. Currently, most of wind energy input is, as a matter of fact, a waste since the commercially available wind power generators only operate for fairly mild or low-speed wind field. To prevent any potential damage due to collision by shaft against conventional bearings, the AMB unit is proposed to replace the traditional bearings and regulate the shaft position deviation. By singular perturbation order-reduction technique, a lower-order plant model can be established for the synthesis of feedback controller. It is found that two major system parameter uncertainties, an additive uncertainty and a multiplicative uncertainty, are constituted by the wind turbine and the VIF, respectively. The upper bounds of system parameters variation can be therefore estimated and the frequency shaping sliding mode control (FSSMC) loop is proposed to account for these uncertainties and suppress the unmodeled higher-order plant dynamics. At last, the efficacy of the FSSMC is verified by intensive computer and experimental simulations for regulation on position deviation of the shaft and counter-balance of unpredictable wind disturbance.     

Propagation of short pulses in an active nonlinear two-core optical fiber

The switching dynamics of short pulses in an active nonlinear two-core fiber coupler is investigated theoretically. The analysis takes into account the effects of coupling-coefficient dispersion, gain bandwidth, and gain saturation. In particular, we demonstrate that the pulse breakup effect due to coupling-coefficient dispersion can be suppressed by limiting the bandwidth of the linear gain, whether gain saturation is considered or not.     

CDNPatch: a cost‐effective failover mechanism for hybrid CDN‐P2P live streaming systems

Among the most well‐established live media distribution technologies is content delivery network (CDN), which improves user‐perceived quality of service by delivering content from proxy servers deployed at the Internet's edge. In recent years, CDN providers started to tap into their subscribers' peer‐to‐peer (P2P) capacity to alleviate their server costs. Under the inherent peer dynamics, a major challenge of these hybrid CDN‐P2P systems is to provide efficient failure recovery with good quality of service guarantees at a reduced server cost. In this work we propose a cost‐effective failover solution named CDNPatch to address the aforementioned problem. CDNPatch enables peers to periodically precompute a few backup content suppliers by efficient information exchange and maintenance algorithms, and leverages auxiliary CDN servers and an economic server provisioning algorithm to reduce the chance of playback interruption occurring to peers. Our simulation results show that CDNPatch can mask the impact of peer dynamics of 3 real P2P systems, namely, SOPCast, PPStream, and PPTV, with 100 % failure recovery success rate and a failure recovery time less than 1 second at a cost of small P2P communication overhead of less than 1 kilobits per second, while using only 10%, 21%, and 51%, respectively, of the pure CDN scheme's server consumption.     

Unprecedented Homoleptic Bis‐Tridentate Iridium(III) Phosphors: Facile,Scaled‐Up Production,and Superior Chemical Stability

Bis‐tridentate Ir(III) metal complexes are expected to show great potential in organic light‐emitting diode (OLED) applications due to the anticipated, superb chemical and photochemical stability. Unfortunately, their exploitation has long been hampered by lack of adequate methodology and with inferior synthetic yields. This hurdle can be overcome by design of the first homoleptic, bis‐tridentate Ir(III) complex [Ir(pzpyph)(pz^Hpyph)] ( 1 ), for which the abbreviation (pzpyph)H (or pz^Hpyph) stands for the parent 2‐pyrazolyl‐6‐phenyl pyridine chelate. After that, methylation and double methylation of 1 afford the charge‐neutral Ir(III) complex [Ir(pzpyph)(pz^Mepyph)] ( 2 ) and cationic complex [Ir(pz^Mepyph)₂][PF₆] ( 3 ), while deprotonation of 1 gives formation of anionic [Ir(pzpyph)₂][NBu₄] ( 4 ), all in high yields. These bis‐tridentate Ir(III) complexes 2 – 4 are highly emitted in solution and solid states, while the charge‐neutral 2 and corresponding t ‐butyl substituted derivative [Ir(pzpy^Buph)(pz^Mepy^Buph)] ( 5 ) exhibit superior photostability versus the tris‐bidentate references [Ir(ppy)₂(acac)] and [Ir(ppy)₃] in toluene under argon, making them ideal OLED emitters. For the track record, phosphor 5 gives very small efficiency roll‐off and excellent overall efficiencies of 20.7%, 66.8 cd A^?1, and 52.8 lm W^?1 at high brightness of 1000 cd m^?2. These results are expected to inspire further studies on the bis‐tridentate Ir(III) complexes, which are judged to be more stable than their tris‐bidentate counterparts from the entropic point of view.     

数字产品存储器和缓冲器的设计思想

存储器是许多数字产品的关键内置模块.标准的SRAM、DRAM和非易失性存储器(NVMs)是最常用的存储器件.特殊的存储器,例如先进先出存储器,也可提供特定功能或实现特殊性能需求.在下面内容中,我们将回顾这些设计,并介绍一些存储器可能的应用场合.这些设计思路可以应用到SoC(芯片级系统)项目中.     

Carbon Free and Noble Metal Free Ni2Mo6S8 Electrocatalyst for Selective Electrosynthesis of H2O2

Electrocatalytic two-electron reduction of oxygen is a promising method for producing sustainable H₂O₂ but lacks low-cost and selective electrocatalysts. Here, the Chevrel phase chalcogenide Ni₂Mo₆S₈ is presented as a novel active motif for reducing oxygen to H₂O₂ in an aqueous electrolyte. Although it has a low surface area, the Ni₂Mo₆S₈ catalyst exhibits exceptional activity for H₂O₂ synthesis with >90% H₂O₂ molar selectivity across a wide potential range. Chemical titration verified successful generation of H₂O₂ and confirmed rates as high as 90 mmol H₂O₂ g_cat⁻¹ h⁻¹. The outstanding activities are attributed to the ligand and ensemble effects of Ni that promote H₂O dissociation and proton-coupled reduction of O₂ to HOO*, and the spatial effect of the Chevrel phase structure that isolates Ni active sites to inhibit O O cleavage. The synergy of these effects delivers fast and selective production of H₂O₂ with high turn-over frequencies of ≈30 s⁻¹. In addition, the Ni₂Mo₆S₈ catalyst has a stable crystal structure that is resistive for oxidation and delivers good catalyst stability for continuous H₂O₂ production. The described Ni-Mo₆S₈ active motif can unlock new opportunities for designing Earth-abundant electrocatalysts to tune oxygen reduction for practical H₂O₂ production.     

Power consumption of analog circuits: a tutorial

A systematic approach to the power consumption of analog circuits is presented. The power consumption is related to basic circuit requirements, as dynamic range, bandwidth, noise figure and sampling speed and is considering basic device and device scaling behavior. Several kinds of circuits are treated, as samplers, amplifiers, filters and oscillators. The objective is to derive lower bounds to power consumption in analog circuits, to be used as design targets when designing power-constrained analog systems.     

Full-Vectorial Optical Waveguide Mode Solvers Using Multidomain Pseudospectral Frequency-Domain (PSFD) Formulations

New full-vectorial optical waveguide eigenmode solvers using pseudospectral frequency-domain (PSFD) formulations for optical waveguides with arbitrary step-index profile are presented. Both Legendre and Chebyshev collocation methods are considered in the formulation. By applying Legendre-Lagrange or Chebyshev-Lagrange interpolating polynomials to the approximation of spatial derivatives at collocation points, the Helmholtz equations for the transverse-electric or transverse-magnetic components are converted into a matrix eigenvalue equation which is then solved for the eigenmodes by the shift inverse power method. Suitable multidomain division of the computational domain is arranged to deal with general curved interfaces of the refractive-index profile together with a curvilinear mapping technique for each subdomain so that field continuity conditions can be carefully imposed across the dielectric interfaces, which is essential in achieving high numerical accuracy. The solver is applied to the optical fiber for the assessment of its numerical performance, to the classical benchmark rib waveguide for comparing with existing high-accuracy results, and to the fused fiber structure for demonstrating its robustness in calculating the form birefingence.     

Technologies and the development of the Automated Metadata Indexing and Analysis (AMIA) system

The Automated Metadata Indexing and Analysis (AMIA) project aims to provide an effective digital asset management (DAM) tool for large digital asset databases. We began with text-based indexing since it is still the most reliable approach as compared with other content-based media features. AMIA not only searches for the text of the file name, but also utilizes embedded information such as the metadata in Maya files. The AMIA system builds a linked map between all dependency files. We present an approach of preserving previously established metadata created by the old DAM tools, such as AlienBrain, and integrating them into the new system. Findings indicate that AMIA has significantly improved search performance comparing to previous DAM tools. Finally, the ongoing and future work in the AMIA project is described.