Forecasting peak air pollution levels using NARX models

Air pollution has a negative impact on human health. For this reason, it is important to correctly forecast over-threshold events to give timely warnings to the population. Nonlinear models of the nonlinear autoregressive with exogenous variable (NARX) class have been extensively used to forecast air pollution time series, mainly using artificial neural networks (NNs) to model the nonlinearities. This work discusses the possible advantages of using polynomial NARX instead, in combination with suitable model structure selection methods. Furthermore, a suitably weighted mean square error (MSE) (one-step-ahead prediction) cost function is used in the identification/learning process to enhance the model performance in peak estimation, which is the final purpose of this application. The proposed approach is applied to ground-level ozone concentration time series. An extended simulation analysis is provided to compare the two classes of models on a selected case study (Milan metropolitan area) and to investigate the effect of different weighting functions in the identification performance index. Results show that polynomial NARX are able to correctly reconstruct ozone concentrations, with performances similar to NN-based NARX models, but providing additional information, as, e.g., the best set of regressors to describe the studied phenomena. The simulation analysis also demonstrates the potential benefits of using the weighted cost function, especially in increasing the reliability in peak estimation.     

Watch out, Tiger Woods![golf playing robot]

This article describes the development of an autonomous robotic system for playing mini-golf. The system was designed and built to serve as a demonstration of robotic application for engineering students. The system was built using a Yasakawa robot fitted with two arms. The software was developed to control the machine using the C++ language. Standard C++ libraries were used in addition to communication libraries provided by the Yasakawa Corporation. The current configuration works with Microsoft Windows NT and an Ethernet environment. This article describes the hardware and software design aspects of this machine.     

Geotextile filtration opening size under tension and confinement

Nonwoven geotextiles have been used as filters in geotechnical and geoenvironmental works for half a century. They are easy to install and can be specified to meet the requirements for proper filter performance. There are situations where a geotextile filter may be subjected to tensile loads, which may alter relevant filter properties, such as its filtration opening size. Examples of such situations are silty fence applications, geotextile separators, geotextile tubes and geotextiles under embankments on soft soils. This paper investigates the effects of tensile strains on geotextile pore dimensions. A special equipment and testing technique allowed tests to be carried out on geotextile specimens subjected to tension and confinement. The results obtained showed that the variation in filtration opening size depends on the type of strain state the geotextile is subjected, under which the geotextile pore diameter may remain rather constant or increase significantly. However, confinement reduces the geotextile filtration opening size independent on the strain mobilised. An upper bound for the filtration opening size of strained nonwoven geotextiles is introduced and was satisfactory for the geotextile products tested.     

Are HFC buses a feasible alternative for urban transportation in Paraguay?

Paraguay is very rich in hydropower and a net importer of fossil fuels. Besides, in Paraguay, the transportation sector counts for a big share of the total energy demand. So if this sector would be changed to clean fuel, imported oil dependence and air pollution will be reduced dramatically. This paper assesses the feasibility of HFC urban buses implementation in the transportation sector in Paraguay. In general, annual transportation cost for a fleet of 55 HFC urban buses is estimated in US$ 33,682,581 compared with US$ 40,612,741.84 for diesel urban buses, which indicates that this technology could be an economical and environmentally clean alternative to substitute diesel urban buses in the Paraguayan transportation sector. These results are strongly linked to the chosen boundary conditions, such as electricity price and availability, the electrolytic hydrogen demand and the basic electrolyser's management.     

Revisitation of Formaldehyde Aniline Condensation. VII. 1,3,5-Triarylhexahydro-sym-triazines and 1,3,5,7-Tetraaryl-1,3,5,7-tetrazocines from Aromatic Amines and Paraformaldehyde

A product study of the reaction between a number of aromatic amines substituted with widely different groups and paraformaldehyde in inert solvents was performed and found to yield 1,3,5-triaryl-1,3,5-hexahydrotriazines, 1,3,5,7-tetraaryl-1,3,5,7-tetrazocines and formaminals. It was not possible to correlate the product outcomes with the actual structure of the amine substrate. The X-ray diffraction structural determination of 1,3,5-tri-(t-butylphenyl)-( 1b ) and 1,3,5-tri-(m-fluorophenyl)-1,3,5-hexahydrotriazine ( 1c ) showed the diaxial arrangement of the N-substituents.     

Matching and mismatching: The effect of own limit, other's toughness, and time pressure on concession rate in negotiation.

Augmented the research design used by H. H. Kelley et al (1967) to examine negotiation about the division of a common reward to include 2 factors expected to interact with bargainer's limit: time pressure and the other bargainer's toughness. Five hypotheses were tested: (1) Concession rate is lower the higher a bargainer's limit; (2) concession rate is greater under high, as opposed to low, time pressure; (3) bargainer toughness is mismatched, that is, the greater the other's initial demand and the slower the other's concessions, the larger will be the S's concessions; (4) concession rate is more influenced by limit level under high, as opposed to low, time pressure; and (5) mismatching of the other's toughness is more pronounced under high time pressure than under low. Ss were 48 female undergraduates. All hypotheses were supported except Hypothesis 3, which received partial support. Ss conceded slowly when the other conceded slowly and rapidly when the other conceded rapidly. A possible explanation for this finding is that matching occurs when it is possible to judge the fairness of the other's offers. When this is possible, bargainers engage in reciprocity. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intra-Period (Within-Day) Dynamic Models for Continuous Services

To simulate important aspect of some transportation systems (e.g. demand peaks, temporary capacity variations, temporary over-saturation of supply elements, and formation and dispersion of queues) a new class of models, referred to in the literature as Dynamic Traffic Assignment (DTA) models, have been recently developed. Although Dynamic Traffic Assignment to networks is a relatively new research subject, a great number of models have been proposed in the last two decades. These can be divided in two main classes according to the typology of service they aim at simulating. These are continuous services, considering transportation services available at any time and accessible from several points, such as the services offered by individual road modes (car, bicycle etc.), and scheduled services simulating services available only at certain times and that can be accessed only at certain locations (terminals, stations, airports etc.). In this paper the focus is on continuous services. Models proposed in the literature are reviewed and classified according to basic assumptions on the flow structure, i.e. whether a continuous or a discrete approach is followed, and on the representation of time (discrete vs. continuous). A general modeling framework consisting of supply, demand, and demand-supply interaction models, and including most of the existing specifications is presented both for the discrete time-discrete flow and continuous time continuous flow cases.     

Biomimetic Concealing of PLGA Microspheres in a 3D Scaffold to Prevent Macrophage Uptake

Scaffolds functionalized with delivery systems for the release of growth factors is a robust strategy to enhance tissue regeneration. However, after implantation, macrophages infiltrate the scaffold, eventually initiating the degradation and clearance of the delivery systems. Herein, it is hypothesized that fully embedding the poly(d,l ‐lactide‐co‐glycolide acid) microspheres (MS) in a highly structured collagen‐based scaffold (concealing) can prevent their detection, preserving the integrity of the payload. Confocal laser microscopy reveals that non‐embedded MS are easily internalized; when concealed, J774 and bone marrow‐derived macrophages (BMDM) cannot detect them. This is further demonstrated by flow cytometry, as a tenfold decrease is found in the number of MS engulfed by the cells, suggesting that collagen can cloak the MS. This correlates with the amount of nitric oxide and tumor necrosis factor‐α produced by J774 and BMDM in response to the concealed MS, comparable to that found for non‐functionalized collagen scaffolds. Finally, the release kinetics of a reporter protein is preserved in the presence of macrophages, only when MS are concealed. The data provide detailed strategies for fabricating three dimensional (3D) biomimetic scaffolds able to conceal delivery systems and preserve the therapeutic molecules for release.