Machine learning in control of functional electrical stimulationsystems for locomotion

Two machine learning techniques were evaluated for automatic design of a rule-based control of functional electrical stimulation (FES) for locomotion of spinal cord injured humans. The task was to learn the invariant characteristics of the relationship between sensory information and the FES-control signal by using off-line supervised training. Sensory signals were recorded using pressure sensors installed in the insoles of a subject's shoes and goniometers attached across the joints of the affected leg. The FES-control consisted of pulses corresponding to time intervals when the subject pressed on the manual push-button to deliver the stimulation during FES-assisted ambulation. The machine learning techniques used were the adaptive logic network (ALN) and the inductive learning algorithm (IL). Results to date suggest that, given the same training data, the IL learned faster than the ALN while both performed the test rapidly. The generalization was estimated by measuring the test errors and it was better with an ALN, especially if past points were used to reflect the time dimension. Both techniques were able to predict future stimulation events. An advantage of the ALN over the IL was that ALN's can be retrained with new data without losing previously collected knowledge. The advantages of the IL over the ALN were that the IL produces small, explicit, comprehensible trees and that the relative importance of each sensory contribution can be quantified     

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.     

嵌入式POL DC/DC转换器设计

大多数嵌入式系统都是通过48V背板供电的。这个电压通常要降为更低的12V或5V中间电压,以向系统内的电路板供电。然而,在这些电路板上,大多数电路都要求供电电压范围在0.8V～3.3V,电流范围为几十mA至几十A。因此,需要负载点(POL)DC/DC转换器对12V或5V降压,以获得所需的电压和电流值。     

The manufacture and performance of diodes made in dielectricallyisolated silicon substrates containing buried metallic layers

Results are reported on the performance of diffused p⁺n diode structures manufactured on a novel silicon-on-metal-on-insulator (SMI) substrate. This substrate consists of a thin single crystal silicon layer on top of a tungsten disilicide covered oxidized silicon wafer. The diodes show excellent characteristics with an exponential current-voltage (I-V) relationship over nine orders of magnitude and an ideality factor of 1.005, under forward bias conditions. The reverse leakage current is low with a minority carrier lifetime of typically 500 μs. The diodes show no evidence of stress induced defects or degraded performance due to W migration during processing. The SMI substrate is therefore shown to be compatible with standard manufacturing processes     

Organic Photovoltaic Cells Based On Solvent‐Annealed,Textured Titanyl Phthalocyanine/C60 Heterojunctions

Organic photovoltaic cells (OPV) with good near‐IR photoactivity are created from highly textured titanyl phthalocyanine (TiOPc)/C₆₀ heterojunctions. Vacuum deposited TiOPc thin films are converted to the near‐IR absorbing “Phase II” polymorph using post‐deposition solvent annealing. The Phase I → Phase II transition broadens the absorbance spectrum of the Pc film producing absorptivities (α ≈ 10⁵ cm^?1) from 600–900 nm, along with substantial texturing of the Pc layer. Atomic force microscopy and field‐emission scanning electron microscopy of the solvent annealed films show that the surface roughness of the Pc layers is increased by a factor of greater than 2× as a result of the phase transformation. Current–voltage (J–V) responses for white light illumination of ITO (100 nm)/TiOPc (20 nm)/C₆₀ (40 nm)/BCP (10 nm)/Al (100 nm) OPVs show a near doubling of the short‐circuit photocurrent (J_SC), with only a small decrease in open‐circuit photopotential (V_OC), and a concomitant increase in power conversion efficiency. Incident photon current efficiency (IPCE) plots confirmed the enhanced near‐IR OPV activity, with maximum IPCE values of ca. 30% for devices using Phase II‐only TiOPc films. UV‐photoelectron spectroscopy (UPS) of TiOPc/C₆₀ heterojunctions, for both Phase I and Phase II TiOPc films, suggest that the Phase II polymorph has nearly the same HOMO energy as seen in the Phase I polymorph, and similar frontier orbital energy offsets, E_HOMO^Pc–E_LUMO^C60, leading to comparable open‐circuit photovoltages. These studies suggest new strategies for the formation of higher efficiency OPVs using processing conditions which lead to enhance near‐IR absorptivities, and extensive texturing of crystalline donor or acceptor films.     

Crystallization-Directed Anisotropic Electroactuation in Selectively Solvated Olefinic Thermoplastic Elastomers: A Thermal and (Electro)Mechanical Property Study

Dielectric elastomers (DEs), a class of soft electroactive polymers that change size upon exposure to an external electric field, constitute an increasingly important class of stimuli-responsive polymers due primarily to their large actuation strains, facile and low-cost fabrication, scalability, and mechanical robustness. Unless purposefully constrained, most DEs exhibit isotropic actuation wherein size changes are the same in all actuation directions. Previous studies of DEs containing oriented, stiff fibers have demonstrated, however, that anisotropic actuation along a designated direction is more electromechanically efficient since this design eliminates energy expended in nonessential directions. To identify an alternative, supramolecular-level route to anisotropic electroactuation, we investigate the thermal and mechanical properties of novel thermoplastic elastomer gels composed of a selectively solvated olefinic block copolymer that not only microphase-separates but also crystallizes upon cooling from the solution state. While these materials possess remarkable mechanical attributes (e.g., giant strains in excess of 4000%), their ability to be strain-conditioned enables huge anisotropic actuation levels, measured to be greater than 30 from the ratio of orthogonal actuation strains. This work establishes that crystallization-induced anisotropic actuation can be achieved with these DEs.     

能源采集,终于等到了

背景＂能量采集＂的概念自2000年初就出现了,但凭借着近期的技术发展,相关的概念才推展至商业化阶段。目前,全球的工程师们都积极地开发着利用非传统型能源的新颖方法。     

Solution of semiconductor equations using a fully adaptive mesh strategy

The letter presents a novel means of mesh adaption when the finite-element method is applied to the semiconductor equations. Using triangular elements it has the ability to avoid obtuse angles while still allowing flexibility in mesh design. The usefulness of the method is demonstrated by a simulation of an MOS device operating at a high drain voltage where generation due to impact ionisation becomes significant.     

Parallel secretion of digestive enzymes by the in vitro rabbit pancreas

Nonparallel discharge of digestive enzymes by the in vitro rabbit pancreas has been previously reported and this observation has been used to challenge the mass transport theory of enzyme synthesis and secretion by the exocrine pancreas. The current investigation reexamines the pattern of enzyme secretion from the in vitro rabbit pancreas. Secretion of alpha-amylase, trypsinogen, and chymotrypsinogen was studied from the unstimulated gland and from glands stimulated with either methacholine, cholecystokinin-pancreozymin, or the active octapeptide of cholecystokinin-pancreozymin. In all cases, only parallel discharge of alpha-amlyse, trypsinogen, and chymotrypsinogen was noted. These observations are consistent with the mass-transport theory.     

Upper airway obstruction induced by warfarin sodium

I report a patient in whom warfarin sodium induced upper airway obstruction secondary to a spontaneous nontraumatic hemorrhage into the sublingual space. Treatment of this obstructive sublingual space hematoma with conservative medical management is reviewed. I discuss the role of warfarin sodium in coagulation and in the production of this pseudo-Ludwig phenomenon.