A Wavelet Packet Tree Denoising Algorithm for Images of Atomic‐Force Microscopy

A threshold‐free denoising procedure of acquired discrete Atomic‐force microscopy (AFM) signals using the discrete wavelet transform (DWT) method is presented in this article. The integration of a denoising procedure into a control structure is extremely important for each kind of system to be controlled. The detection of unavoidable measurement noise in the acquired data of the AFM signal is done by using orthogonal wavelets (Daubechies and Symmlet) and with different polynomial approximation order for each family. The proposed denoising algorithm, based on the free wavelet toolboxes from the WaveLab 850 library of the Stanford University (USA), compares the usefulness of Daubechies and Symmlet wavelets with different vanishing moments. With the help of a seminorm the noise of a sequence is defined as a coherent and incoherent part of the AFM signal. In the first step of the procedure the algorithm analyzes the frequency subspaces of the wavelet packets tree and searches for small or opposing components in the wavelet domains. In the second step of the procedure the incoherent components in the low‐ and high frequency domains are localized and the incoherent is then removed from the AFM signal. The proposed algorithm structure is used to improve the quality of the AFM signals and it can be easily integrated into the existing AFM control hard‐ and software structures. The effectiveness of the proposed denoising algorithm is validated with real measurements.     

Tire lateral force estimation and grip potential identification using Neural Networks,Extended Kalman Filter,and Recursive Least Squares

This paper presents a novel hybrid observer structure to estimate the lateral tire forces and road grip potential without using any tire–road friction model. The observer consists of an Extended Kalman Filter structure, which incorporates the available prior knowledge about the vehicle dynamics, a feedforward Neural Network structure, which is used to estimate the highly nonlinear tire behavior, and a Recursive Least Squares block, which predicts the road grip potential. The proposed observer was evaluated under a wide range of aggressive maneuvers and different road grip conditions using a validated vehicle model, validated tire model, and sensor models in the simulation environment IPG CarMaker ^®. The results confirm its good and robust performance.

     

Evaluation of e-commerce websites accessibility and usability: an e-commerce platform analysis with the inclusion of blind users

Considering the importance associated with e-commerce website accessibility and usability, a study on one of the most relevant Portuguese e-commerce websites has been performed using both automatic and manual assessment procedures. In an initial stage, we evaluated the chosen website with a Web accessibility and usability automatic tool called SortSite; after that, we performed a manual evaluation to verify each previously detected error and present possible solutions to overcome those faults. In a third phase, three usability specialists have been used to perform a heuristic evaluation of the chosen website. Finally, user tests with blind people were carried out in order to fully assess the compliance with accessibility and usability guidelines and standards. The results showed that the platform had a good score regarding the automatic evaluation; however, when the heuristic and manual evaluations were performed, some accessibility and usability problems were discovered. Moreover, the user test results showed bad marks regarding efficiency, effectiveness, and satisfaction by the group of participants. As a conclusion, we highlight user interaction problems and propose seven recommendations focused on enhancing accessibility and usability of not only the evaluated e-commerce website, but also of other similar ones.     

Software architectural patterns in practice: an empirical study

Software architecture involves a series of decisions based on many factors in a wide range of software development. Architects face recurring issues in different software architecture design, and to reduce huge cost and risks, software architecture decisions can rely on a set of idiomatic patterns commonly named architectural styles or patterns. Architectural pattern determines the vocabulary of components and connectors that are used in instances of the pattern together with a set of constraints to combine the two. Little contemporary data exists to document actual practices used by software professionals when selecting and incorporating architectural patterns for their projects in industry. Therefore, a comprehensive survey of software professionals was conducted to attempt to discover these practices. This exploratory survey and its quantitative results offer opportunities for further interpretation and comparison. Data from this survey are presented in this paper and include characteristics of projects, practices, organizations, and practitioners related to the usage of architectural patterns. Some of the notable findings include that architectural patterns are widely used in software projects with the Model–View–Controller being the most common. Despite reported difficulties in incorporating architectural patterns, the majority of the software professionals revealed that patterns were the most essential for completing the projects. The most difficult pattern to implement and the most expensive to adopt was the peer-to-peer, while the easiest was the client–server.

     

Biodiversity offsets in South Africa – challenges and potential solutions

South Africa has a decade of experience designing and implementing biodiversity offsets. In the absence of explicit national policy on biodiversity offsets, the country has relied on existing legal provisions in environmental law as the basis for offset requirements, supported by provincial guidelines. South Africa’s periodic national biodiversity surveys provide scientifically rigorous quantification and mapping for individual ecosystems and finer scale surveys identify biodiversity priority areas, primed as ‘offset receiving areas’. Yet despite enabling factors the use of offsets has frequently been inadequate to deliver intended biodiversity outcomes. Challenges include: (a) the absence of national policy to drive and shape offset implementation; (b) insufficient capacity to evaluate, design and implement offsets; (c) inconsistent decision-making; (d) problems establishing sustainable financing mechanisms; and (e) inadequate enforcement and monitoring, linked to poor drafting of licencing conditions and/or insufficient capacity to monitor implementation. South Africa’s experience provides valuable insights into the challenges and potential solutions for making offsets work for biodiversity conservation and offers important lessons for the development and implementation of biodiversity offsetting in other developing countries.     

Hydrogen sorption enhancement in cold-rolled and ball-milled CaNi<Subscript>5</Subscript>

The effect of cold rolling and ball milling on the hydrogen sorption properties of CaNi₅ was investigated with a special emphasis on the first hydrogenation. We compared cold rolling for 5, 12, and 25 rolling passes in the air with ball milling in argon for 30 and 60 min. Results show that 15 min of ball milling had a positive effect on the first hydrogen absorption, but further milling to 60 min made the sample almost impermeable to hydrogen. Cold rolling had a positive effect on first hydrogenation. We found that cold rolling greatly reduces the particle size as well as the crystallite size. We also found that dehydrogenation under 5 kPa of hydrogen at 323 K was not complete. Two partially hydride phases remained: CaNi₅H and Ca₂Ni₇H _x .     

Synthesis,characterization and in situ monitoring of the mechanochemical reaction process of two manganese(II)-phosphonates with N-containing ligands

Two divalent manganese aminophosphonates, manganese mono(nitrilotrimethylphosphonate) (MnNP₃) and manganese bis(N-(carboxymethyl)iminodi(methylphosphonate)) (Mn(NP₂AH)₂), have been prepared by mechanochemical synthesis and characterized by powder X-ray diffraction (PXRD). The structure of the novel compound Mn(NP₂AH)₂ was determined from PXRD data. MnNP₃ as well as Mn(NP₂AH)₂ exhibits a chain-like structure. In both cases, the manganese atom is coordinated by six oxygen atoms in a distorted octahedron. The local coordination around Mn was further characterized by extended X-ray absorption fine structure. The synthesis process was followed in situ by synchrotron X-ray diffraction revealing a three-step reaction mechanism. The as-prepared manganese(II) phosphonates were calcined on air. All samples were successfully tested for their suitability as catalyst material in the oxygen evolution reaction.     

Non‐normal Capability Indices for the Weibull and Lognormal Distributions

Because the normal process capability indices (PCIs) C_p, C_pu, C_pl, and C_pk represent the times that the process standard deviation is within the specification limits; then, based on and by using the direct relations among the parameters of the Weibull, Gumbel (minimum extreme value type I) and lognormal distributions, the Weibull and lognormal PCIs are derived in this paper. On the other hand, because the proposed PCIs P_p, P_pu, P_pl, and P_pk were derived as a function of the mean and standard deviation of the analyzed process, they have the same practical meaning with those of the normal distribution. Results show that the proposed PCIs could be used as the standard C_p, C_pu, C_pl, and C_pk if a short‐term variance is analyzed. An application to a set of simulated data is presented. Copyright © 2015 John Wiley & Sons, Ltd.