Evaluation of the stability of intracortical microelectrode arrays.

In order to use recorded neural activities from the brain as control signals for neuroprosthesis devices, it is important to maintain a stable interface between chronically implanted microelectrodes and neural tissue. Our previous paper introduced a method to quantify the stability of the recording microelectrodes. In this paper, the method is refined 1) by incorporating stereotypical behavioral patterns into the spike sorting program and 2) by using a classifier based on Bayes theorem for assigning the recorded action potentials to the underlying neural generators. An improved method for calculating stability index is proposed. The results for the stability of microelectrode arrays that differ in structure are presented.     

New Power Semiconductor Devices for Future Generations of Power Supplies

Power Semiconductors are still the driving force for many power electronic systems.In this paper the development of the key power semiconductors devices for power supplies are shown,and their electrical performance discussed.Future directions of the major power semiconductor devices like the IGBT,Super Junction technology and SiC device will be explained.     

Charge-Transfer Effect of GZO Film on Photochemical Water Splitting of Transparent ZnO@GZO Films by RF Magnetron Sputtering

With the purpose of enhancing the photochemical water splitting performance, GZO film has been used to increase the charge transfer of the ZnO@GZO films. The characterization of ZnO film, GZO film and ZnO@GZO films was carried out by X-ray diffraction (XRD), atomic force microscope, DRUV-vis spectra (DRUV-vis), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and photochemical water splitting. All samples show a related highly c-axis peak (002) from XRD patterns. DRUV-vis results show that the formed GZO film with wide band gap but low resistivity, would not affect the band gap of the ZnO@GZO films. PL results reveal that the decreased recombination of electron and hole, via the increased charge transfer by GZO film. XPS results hint that the obvious change of chemisorbed oxygen species on the surface of ZnO and GZO, and Ga atoms mainly substitute into Zn sites in the ZnO matrix. Compared with that of ZnO film, the ZnO@GZO films even with lower specific surface area, could efficiently enhance the photochemical water splitting performance via the charge-transfer effect of the GZO film.     

Species-specific composition of free amino acids on the leaf surface of fourSenecio species

The specificity of the chemical composition of the leaf surface of fourSenecio species was studied in order to understand the host selection ofTyria jacobaeae, a monophagous moth that hasSenecio jacobaea as its principal host plant. Pyrrolizidine alkaloids characteristic forSenecio species were not detected in water and sulfuric acid extracts of the leaf surface ofSenecio jacobaea. Water extracts of the leaf surfaces ofS. jacobaea, S. vulgaris, S. viscosus, andS. sylvaticus contained low concentrations of free amino acids. The proportions of these amino acids were very different from those inside the leaf tissues. In a discriminant analysis, the four species could be completely separated on the basis of the relative proportions of amino acids on the leaf surface.     

Analysis of Instability in Electrical Machines

While there exist numerous studies of electromechanical instabilities of specific electrical machines in constant or periodic speed operation, a broader perspective is not commonly offered. In contrast, a general machine model is used here to present essential and common features of these stability analyses. Fundamental issues are illuminated at this level of generality before specialization to the details of a specific machine. To begin, Park-transformable machines in constant-speed operation are considered. The local dynamics of these machines are linear and time-invariant. For such machines it is shown that instability may be analyzed in a useful way via systematically obtained reduced-order models. This is illustrated by significantly expanding an earlier study of a hybrid stepping motor. The more general situation in which the linearized models that govern local behavior are periodically varying is considered next. Classical Floquet theory is reviewed to provide the tools needed for stability analysis in this situation.     

Recursive segmentation and recognition templates for image parsing

In this paper, we propose a Hierarchical Image Model (HIM) which parses images to perform segmentation and object recognition. The HIM represents the image recursively by segmentation and recognition templates at multiple levels of the hierarchy. This has advantages for representation, inference, and learning. First, the HIM has a coarse-to-fine representation which is capable of capturing long-range dependency and exploiting different levels of contextual information (similar to how natural language models represent sentence structure in terms of hierarchical representations such as verb and noun phrases). Second, the structure of the HIM allows us to design a rapid inference algorithm, based on dynamic programming, which yields the first polynomial time algorithm for image labeling. Third, we learn the HIM efficiently using machine learning methods from a labeled data set. We demonstrate that the HIM is comparable with the state-of-the-art methods by evaluation on the challenging public MSRC and PASCAL VOC 2007 image data sets.     

Mechanising a formal model of flash memory

We present second steps in the construction of formal models of NAND flash memory, based on a recently emerged open standard for such devices. The model is intended as a key part of a pilot project to develop a verified file store system based on flash memory. The project was proposed by Joshi and Holzmann as a contribution to the Grand Challenge in Verified Software, and involves constructing a highly assured flash file store for use in space-flight missions. The model is at a level of abstraction that captures the internal architecture of NAND flash devices. In this paper, we focus on mechanising the state model and its initialisation operation, where most of the conceptual complexity resides.     

Quantum steering borders in three-qubit systems

We discuss a family of states describing three-qubit systems in a context of quantum steering phenomena. We show that symmetric steering cannot appear between two qubits—only asymmetric steering can appear in such systems. The main aim of this paper is to discuss the possible relations between the entanglement measures and steering parameter for two-mode mixed state corresponding to the qubit–qubit subsystem. We have derived the conditions determining boundary values of the negativity parametrized by concurrence. We show that two-qubit mixed state cannot be steerable when the negativity of such state is smaller than, or equal to, its boundary value. Finally, we have found ranges of the values of the mixedness measure, parametrized by concurrence and negativity for steerable and unsteerable two-qubit mixed states.     

On the relationship between subjective and objective measures of fatigue

Objective: Objective and subjective methods have been used in the past to assess workplace fatigue, but little is known about correlations between them. We examine correlations between subjective and objective measures, including measures collected in a workplace scenario. Methods: 15 young and 17 older participants were assessed before and after work with four types of fatigue measure: objective physical (posturography), objective mental (psychomotor vigilance task), subjective physical and mental (self-assessment), objective and subjective realistic (oculomotor behaviour, observer-rated facial expression, typing performance). Results: Pre- and post-test scores were analysed with an ANOVA, significant differences were submitted to a factor analysis. It yielded three factors: one representing posturography, the second self-rated mental and physical fatigue and the third observer-rated facial expression. Conclusions: Results advocate the existence of three independent fatigue components: Objective physical fatigue, introspective and extrospective fatigue.

Practitioner Summary: This study analyses correlations between different subjective and objective fatigue markers to better understand the complex nature of workplace fatigue. Measurements were conducted directly at the workplace. Results reveal that fatigue comprises three independent fatigue components: Objective physical fatigue, introspective and extrospective fatigue.     

Formal methods for security in the Xenon hypervisor

This paper reports on the Xenon project’s use of formal methods. Xenon is a higher-assurance secure hypervisor based on re-engineering the Xen open-source hypervisor. The Xenon project used formal specifications both for assurance and as guides for security re-engineering. We formally modelled the fundamental definition of security, the hypercall interface behaviour, and the internal modular design. We used three formalisms: CSP, Z, and Circus for this work. Circus is a combination of Standard Z, CSP with its semantics given in Hoare and He’s unifying theories of programming. Circus is suited for both event-based and state-based modelling. Here, we report our experiences to date with using these formalisms for assurance.