A Test of Linearity for Functional Autoregressive Models

We propose a new test for linearity in time series. We consider an asymptotically stationary functional AR( p ) model on ℜ ^d of the form
X _n = f ( X _{n −1}, ..., X _{n − p} ) + ξ _n ( n ∈ N).
The testing procedure is based on a suitably normalized sum of quadratic deviations between two different estimates of the function f evaluated at q distinct points of ℜ ^dp . The estimators are f^ _n , a recursive version of the non-parametric kernel estimator of f , and  _n , a least squares estimator well suited to the linear case. The main result states that the test statistic has a χ² limit distribution under the null hypothesis. A similar result is derived under the alternative hypothesis for the test statistic corrupted by a non-linear term. Our simulations indicate that our asymptotic results hold for moderate sample sizes when the testing procedure is used carefully     

Production of low methoxyl pectin using immobilized pectinmethylesterase silica from acerola (Malpighia glabra L.)

The aim of this work was to develop an efficient reactor for the production of low methoxyl pectin, using pectinmethylesterase (PME, EC 3.1.1.11) from acerola immobilized on silica. The immobilized enzyme was used in up to 50 successive bioconversion runs at 50 °C with an efficiency loss of less than 20%. The fixed‐bed reactor (6.0 × 1.5 cm) was prepared using PME immobilized in glutaraldehyde‐activated silica operated at 50 °C with an optimum flow rate of 10 mL h^?1. The bioconversion yield was shown to strongly depend on the nature of the enzymatic preparation. An efficiency of 44% was achieved when concentrated PME was used, compared with only 30% with purified PME, both after an 8‐h run. The process described could provide the basis for the development of a commercial‐scale process. Copyright © 2006 Society of Chemical Industry     

Improvement of various properties of fiber surfaces containing crosslinked polyethylene glycols

Modification of a variety of fabric and fibrous surfaces was achieved by insolubilization thereon of crosslinked polythylene glycols (called POLYTHERM) to impart several useful properties: thermal storage and release, improved resiliency and resistance to oily soiling, static charge, pilling, wear life, and marked increases in hydrophilicity among them. Moreover, these improved properties were durable because up to 70% of the crosslinked polyol was retained after 50 launderings. Such modification was achieved by using average molecular weights of the polyols ranging from 600 to 20,000 by crosslinking with polyfunctional methylolamides (such as DMDHEU) in the presence of acid catalysts by a conventional pad-dry-cure textile finishing procedure. The role of crosslink density of the polyol in determining textile properties was determined by evaluation of films derived from crosslinking the polyols and comparison of selected properties.     

Comparison of Additional Costs for Several Replacement Strategies of Randomly Ageing Reinforced Concrete Pipes

Abstract:   One of the uses of reinforced concrete pipes (RCPs) is the distribution of aggressive water in industrial systems, for example, in water-cooling systems of nuclear power plants. Some of them carry seawater and can deteriorate with time because of internal corrosion. Because of the low O₂ content of aggressive water, slow corrosion is expected for such applications. If the RCPs are not periodically replaced, they will eventually fail. Replacement strategies for these pipes depend on (1) the risks associated with the failure of the water distribution network, and (2) the costs associated with replacing the pipes, including the removal of existing pipes, installation of new pipes, and associated production losses. Because of the lack of statistical data regarding RCP failure, the development of a risk-based replacement strategy is not an easy task. This article demonstrates how predictive models for the evolution of the failure of RCPs and the associated consequences of failure can be used to develop risk-based replacement strategies for RCPs. An application for the replacement strategies of a network modeled as a system consisting of 228 RCPs is presented as a case study. We focus on the assessment of the number of replaced components that governs the costs. The main objective of this article is to provide a theoretical approach for comparing replacement strategies, based on (1) the results of a reliability study, (2) the representation of the distributions of failed components (binomial distribution), and (3) the decision tree representation for replacement of RCPs. A focus on the scatter of the induced costs themselves is suggested to emphasize the financial risk.     

Using automatic differentiation to compute derivatives for a quantum-chemical computer program

The ADIFOR 2.0 tool for Automatic Differentiation of Fortran programs has been used to generate analytic gradient code for all semiempirical SCF methods available in the MNDO97 program. The correctness and accuracy of the new code have been verified. Its performance has been compared with that of hand-coded analytic derivative routines and with numerical differentiation. From a quantum-chemical point of view, the major advance of this work is the development of previously unavailable analytic gradient code for the recently proposed OM1 and OM2 methods.     

PD control with on-line gravity compensation for robots with elastic joints: Theory and experiments

A proportional-derivative (PD) control with on-line gravity compensation is proposed for regulation tasks of robot manipulators with elastic joints. The work extends a previous PD control with constant gravity compensation at the desired configuration. The control law requires measuring only position and velocity on the motor side of the elastic joints, while the on-line gravity compensation torque uses a biased measure of the motor position. It is proved via a Lyapunov argument that the control law globally asymptotically stabilizes the desired robot configuration. A simulation study on a two-joint arm reveals the better performance that can be obtained with the new scheme as compared to the case of constant gravity compensation. Moreover, the proposed controller is experimentally tested on an eight-joint cable-driven robot manipulator, in combination with a point-to-point interpolating trajectory, showing the practical advantages of the on-line compensation.     

Text line segmentation of historical documents: a survey

There is a huge amount of historical documents in libraries and in various National Archives that have not been exploited electronically. Although automatic reading of complete pages remains, in most cases, a long-term objective, tasks such as word spotting, text/image alignment, authentication and extraction of specific fields are in use today. For all these tasks, a major step is document segmentation into text lines. Because of the low quality and the complexity of these documents (background noise, artifacts due to aging, interfering lines), automatic text line segmentation remains an open research field. The objective of this paper is to present a survey of existing methods, developed during the last decade and dedicated to documents of historical interest.     

A multimodal annotated corpus of consensus decision making meetings

In this paper we present an annotated audio–video corpus of multi-party meetings. The multimodal corpus provides for each subject involved in the experimental sessions six annotation dimensions referring to group dynamics; speech activity and body activity. The corpus is based on 11 audio and video recorded sessions which took place in a lab setting appropriately equipped with cameras and microphones. Our main concern in collecting this multimodal corpus was to explore the possibility of providing feedback services to facilitate group processes and to enhance self awareness among small groups engaged in meetings. We therefore introduce a coding scheme for annotating relevant functional roles that appear in a small group interaction. We also discuss the reliability of the coding scheme and we present the first results for automatic classification.     

构成廉价电感测量仪的单个IC

本设计实例显示了如何构建一个可靠的低成本的简单电感测量仪.电感测量仪的基础是一个皮尔斯(Pierce)CMOS缓冲振荡器(图1).代替普通的石英晶体,连接待测电感.