BCI Meeting 2005--workshop on signals and recording methods.

This paper describes the highlights of presentations and discussions during the Third International BCI Meeting in a workshop that evaluated potential brain-computer interface (BCI) signals and currently available recording methods. It defined the main potential user populations and their needs, addressed the relative advantages and disadvantages of noninvasive and implanted (i.e., invasive) methodologies, considered ethical issues, and focused on the challenges involved in translating BCI systems from the laboratory to widespread clinical use. The workshop stressed the critical importance of developing useful applications that establish the practical value of BCI technology.     

Water Content Determinations for Peat and Other Organic Soils Using the Oven-Drying Method

There has been much debate in the literature over the past 60 years regarding an appropriate oven-drying temperature for water content determinations in peat and other organic soils. For inorganic soils, the water content is usually based on the equilibrium dry mass corresponding to drying temperatures in the range 100–110°C. However, for peat and other organic soils, several researchers have recommended lower drying temperatures in the range 60–90°C in an attempt to prevent possible charring, oxidation, and/or vaporization of substances other than pore water. However, all of the relevant water is not fully evaporated at too low a temperature, and because specimen dry mass is a function of drying temperature, the resulting water content values are lower than those determined for the temperature range 100–110°C. Experimental data reported in this article show that oven drying of peat and other organic soils at 100–110°C using either gravity–convection or forced-draft ovens is acceptable for routine water content determinations. Because a standardized oven temperature is desirable when correlating water content with other material properties, it is recommended that oven drying of peat and other organic soils be performed over temperature ranges of either 105–110°C or 105 ± 5°C, in line with standardized ranges for inorganic soils.     

Zn in Athenian Black Gloss Ceramic Slips: A Trace Element Marker for Fabrication Technology

The black‐colored pottery slips produced in Athens from the 6th to 4th centuries B.C., had a consistent composition achieved through processing and refinement of raw clay. Little direct evidence has been established as to what were these refinement methods. To better understand how the slip material was prepared, the major and trace elemental compositions of 19 slips from different ceramic vessels and their corresponding bodies of Athenian red‐figure and black‐figure vases were determined using laser ablation inductively coupled plasma mass spectrometry (LA‐ICPMS). Notably higher Zn concentrations were found in the slips (271–1959 ppm) than in their corresponding body ceramics (<361 ppm). The Zn concentrations in the slips were also found to be above the natural background for typical clay (between 10 and 300 ppm) suggesting an unintentional anthropogenic enrichment of this metal. Based on the abnormally high Zn content of the slip, it is speculated that the clay was treated using vitriol (concentrated acid mine runoff which is rich in Zn), to induce flocculation and remove carbonate mineral phases from the raw material that, if present, would prevent the slip from vitrifying. This same signature of elevated levels of Zn with a corresponding Ce anomaly is also observed for black glosses produced in Corinthian and Etrurian (Italy) workshops indicating that these trace element signatures were imparted to the material by means of shared methods of manufacturing instead of being indicative of a single unique source for this material.     

Vine Copula Specifications for Stationary Multivariate Markov Chains

Vine copulae provide a graphical framework in which multiple bivariate copulae may be combined in a consistent fashion to yield a more complex multivariate copula. In this article, we discuss the use of vine copulae to build flexible semiparametric models for stationary multivariate higher‐order Markov chains. We propose a new vine structure, the M‐vine, that is particularly well suited to this purpose. Stationarity may be imposed by requiring the equality of certain copulae in the M‐vine, while the Markov property may be imposed by requiring certain copulae to be independence copulae.     

Helium permeability of polymer materials as liners for composite overwrapped pressure vessels

Polymers have been identified as replacement materials for metallic liners in composite overwrapped pressure vessels (COPVs) for future space launchers. PEEK, Nylon, and PVDF plastics formed from base powder grades have been permeability tested to determine their susceptibility to the diffusion of helium through flatwise panel cross sections. Permeability, diffusion, and solubility coefficients have been obtained for each material with PVDF and PA11 grades showing the lowest permeability coefficients and hence the best barrier properties to permeation. Crystallinity percentages and internal air void contents in the polymer samples have also been used to assess the differences in permeability between materials with an analysis of void dispersion effects given through X‐ray CT scanning techniques. The measured permeability coefficients have been used to assess the ability of all materials tested to act as a functional polymer liner in a standard COPV with final leak rates predicted based on liner thicknesses and weights. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43675.     

最大程度地延长无线家庭自动化系统中的电池寿命

研究将无线传感器功耗降至最低,从而延长电池寿命的方法.同时考虑那些容易被忽略但对电池寿命和系统性能具有重大影响的参数,以及功率转换、RF性能、通信协议等.介绍了几种良好做法供系统设计人员参考,帮助其深入了解以前可能未曾考虑过的方面.     

Approximate dynamic programming via iterated Bellman inequalities

In this paper, we introduce new methods for finding functions that lower bound the value function of a stochastic control problem, using an iterated form of the Bellman inequality. Our method is based on solving linear or semidefinite programs, and produces both a bound on the optimal objective, as well as a suboptimal policy that appears to works very well. These results extend and improve bounds obtained in a previous paper using a single Bellman inequality condition. We describe the methods in a general setting and show how they can be applied in specific cases including the finite state case, constrained linear quadratic control, switched affine control, and multi‐period portfolio investment. Copyright © 2014 John Wiley & Sons, Ltd.