Design and implementation of a new scheduler for enhancing multi-rate fairness in IEEE 802.16

Without the definition of a mandatory scheduling algorithm for channel resource assignment, WiMAX is open to Quality of Service (QoS) enhancements by research groups and developers, at the aim of managing heterogeneous flows with different QoS requirements. Furthermore, besides performance enhancement, another key issue arises for QoS delivery: it is known as multi-rate fairness and it deals with efficient resource allocation for providing sufficient bandwidth to high rate flows, without penalizing low rate ones. In this paper, uplink scheduling algorithms are studied and an innovative solution is proposed to achieve performance enhancement, multi-rate fairness and improved QoS management. After an overview of the state of the art, two scheduling algorithms based on Deficit Round Robin are studied, implemented and tested in NS2 simulator. The schedulers are validated and compared through exhaustive simulations, showing the benefits coming from the adoption of the proposed scheduling mechanism.     

Personality disorders and psychiatric symptoms in psoriasis

Two groups of psoriatic outpatients (ns = 192 and 119) were given, respectively, the Million Clinical Multiaxial Inventory-II and Foulds' Delusions-Symptoms-States Inventory. They were compared with dental (n = 192) and with general surgical (n = 190) patients. The psoriatic group presented clearly higher mean scores and frequencies on most of the personality disorder scales. On Foulds' inventory, psoriatic patients showed higher frequencies of neurotic and psychotic class allocations. A cluster analysis of personality scores provided evidence for 4 different personality clusters of patients with psoriasis: (a) Avoidant, Dependent, Schizoid, and Self-defeating (32.2%), (b) Compulsive, Narcissistic, and Aggressive (30.7%), (c) no personality disorder (18.2%), (d) Borderline, Paranoid, and Schizotypal, etc. (18.8%).     

Constitutive Model for Municipal Solid Waste

Municipal solid waste (MSW) is a refuse composed of various materials with different properties. Some of the components are stable while others degrade as a result of biological and chemical processes. These aspects impart to MSW a complex behavior that has been modeled, with many limitations, within the concepts of soil mechanics. In this paper, a framework to model the MSW mechanical behavior is proposed based on results from laboratory tests, such as triaxial compression and confined compression of large samples. It is suggested that two different effects command MSW mechanical behavior: (a) the reinforcement of MSW by synthetic fibers (composed by many types of polymers) and (b) the behavior of the MSW paste, without fibers. Accordingly, two distinct frameworks were used to represent the main MSW characteristics: (a) a critical state framework for MSW paste and (b) an elastic perfectly plastic framework for waste fibers, with a time lag for fiber loading (function fm). The proposed model is capable of reproducing quite well the results obtained from triaxial and confined compression tests performed in the laboratory as well as the settlement recorded in a sanitary landfill.     

Simultaneous optimization of design and operation of multicomponent batch distillation column—single and multiple separation duties

A method is presented for the simultaneous optimization of a batch distillation column design and its operation, for single and multiple separation duties, each involving different multicomponent mixtures and complex operations with intermediate cuts. For operation structures selected a priori, the formulation presented permits the use of general distillation design and cost models. The objective function and constraints include capital and operating cost. In particular, the number of internal plates is optimized along with the most significant operating variables (recoveries in various cuts and reflux ratio profiles and times). The multiple duty formulation presented accounts for the different importance of each duty and setup time between batches. Application of the method to single duty multicomponent separation from the literature shows that significant profit improvements can be achieved within acceptable computing times. For multiple separation duties (two binary mixtures), the method clearly shows the importance of including allocation time to each duty and setup time for each batch in the objective function.     

Multi layer structure for encapsulation of organic transistors

A novel encapsulation structure to protect organic thin film transistors against oxygen and moisture contaminations is presented. The sealing architecture is comprised of three-layers: aluminum oxide deposited by means of Atomic Layer Deposition is the actual capping layer, while cross-linked poly-vinylphenol and poly-vinylphenol prevent the contamination/damage of the underlying organic semiconductor during the oxide growth. The process has negligible impact on device mobility but it enables poly-3-hexylthiophene based transistors to operate with an on/off ratio in excess of 10³ even after 100 days of continuous ambient air exposure.     

Impedance of passive oxide films with graded thickness: Influence of the electrode and cell geometry

The impedance of cylindrical electrodes and of rectangular sheet electrodes coated by passive films with either a constant or a graded thickness has been calculated using a finite element method for solving Laplace's equation. The comparison of different electrode/cell geometries characterized by homogenous (on cylindrical electrodes) or inhomogeneous distributions of primary current (on rectangular sheet electrodes) and by homogeneous or graded thickness has allowed to clarify the origin of frequency dispersion phenomena. Calculated curves were compared with experimental impedance plots obtained with Nb and Ta sheet electrodes and with Nb cylindrical electrodes. The results of the finite element calculations for rectangular sheet electrodes are in better agreement with the experiments than those of a previous analytical calculation developed under a simplifying assumption (i.e. identical local electrolyte resistance at each point of the electrode surface) which was equivalent to neglecting current distribution induced by electrode and cell geometry.