Bayes credibility intervals for the left-truncated exponential distribution

In this paper, a Bayes approach for statistical inference on life characteristics is proposed, when the underlying lifetime distribution has the left-truncated exponential density function. The proposed Bayes procedure provides credibility intervals on several life characteristics of great interest to the applied reliability engineer, when the experimental data are collected under a randomly censored sampling. The prior technical knowledge is expressed in the form of a prior density on the reliability level at a prefixed time in conjunction with an upper bound on the location parameter. The statistical properties of the proposed Bayes procedure are compared, via Monte Carlo simulation, with those of the Bayes procedure under the noninformative prior, when both correct and uncorrect prior information on the reliability is available. A numerical example is used for illustration and comparison.     

The KlaperSuite framework for model-driven reliability analysis of component-based systems

Automatic prediction tools play a key role in enabling the application of non-functional requirements analysis, to simplify the selection and the assembly of components for component-based software systems, and in reducing the need for strong mathematical skills for software designers. By exploiting the paradigm of Model-Driven Engineering (MDE), it is possible to automatically transform design models into analytical models, thus enabling formal property verification. MDE is the core paradigm of the KlaperSuite framework presented in this paper, which exploits the KLAPER pivot language to fill the gap between design and analysis of component-based systems for reliability properties. KlaperSuite is a family of tools empowering designers with the ability to capture and analyze quality of service views of their systems, by building a one-click bridge towards a number of established verification instruments. In this article, we concentrate on the reliability-prediction capabilities of KlaperSuite and we evaluate them with respect to several case studies from literature and industry.     

Rheological,thermal and morphological properties of polyethylene terephthalate/polyamide 6/rice husk ash composites

This work deals with the rheological, morphological, and thermal properties of composites having poly(ethylene terephthalate) (PET), polyamide-6 (PA6), and their blends as matrices, and rice husk ash (RHA) as a filler. The study determines the effect of composition on the change in viscosity and rate of degradation during processing in a torque rheometer. Our data indicates that thermal stability and degradation during processing depend on matrix composition and filler concentration. SEM micrographs show both partial adhesion of the filler to the matrices and filler pullout. Optical microscopy shows particle agglomeration and that agglomerate size increased with filler content. FTIR investigates the shifting of absorption bands of PET/PA6 composite after the addition of RHA and attributes the selective dispersion of RHA to the formation of hydrogen bonds. Our data supports the idea that filler employed here is an option to develop polymer composites with improved properties.     

QoS and energy management with Petri nets: A self-adaptive framework

Energy use is becoming a key design consideration in computing infrastructures and services. In this paper we focus on service-based applications and we propose an adaptation framework that can be used to reduce power consumption according to the observed workload. The adaptation guarantees a trade-off between energy consumption and system performance. The approach is based on the principle of proportional energy consumption obtained by scaling down energy for unused resources, considering both the number of servers switched on and their operating frequencies. Stochastic Petri nets are proposed for the modeling of the framework concerns, their analyses give results about the trade-offs. The application of the approach to a simple case study shows its usefulness and practical applicability. Finally, different types of workloads are analyzed with validation purposes.     

Microstructure and chemical degradation of adobe and clay bricks

The environmental degradation of adobe and fired clay brick was studied. Leaching media based on Na₂S₂O₅ solution and deionized water were used. The microstructure of the samples was evaluated by X-ray powder diffraction, nitrogen adsorption–desorption (BET method), Fourier transform infrared spectroscopy and scanning electron microscopy. The predominant phases detected were kaolinite and quartz for both the adobe and fired brick samples. The high surface reactivity, associated with a large amount of OH groups, contributes to the significant degradation of adobe. The fired clay brick showed a significant decrease in the average pore diameter after the first day of the leaching process; its specific surface area exhibited a reduction of about three orders of magnitude. The results of the present investigation contribute to a better understanding of the correlation between structure and leaching behaviour in adobe and clay brick, attending the renewed interest in these materials as environmentally attractive building blocks.     

Sensitivity-oriented versus didactically oriented in-service counselor training.

Compared the effectiveness of 2 different in-service training workshops for counselors. 18 male and 15 female secondary school counselors with a mean age of 37.3 yrs and mean counseling experience of 6.3 yrs served as Ss. 22 Ss were given a 16-hr Carkhuff-type refresher in facilitative interpersonal process plus 8 hrs either of sensitivity experiences or traditional didactic learning. 11 volunteers whose schedules could not be accommodated served as controls. Pre-post criteria of relationship skill were assessed in actual and simulated interviews. Results demonstrate the usefulness of Carkhuff-based training supplemented by group encounter as a professional-skills enhancer, and underscored the transferability of sensitivity training gains to counseling. It is concluded that the interpersonal learning that occurs in a sensitivity context may be a more valuable resource in real-life counseling situations than the learning effected by didactic materials. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modular system for data acquisition and control of experiments with digital output

In the present work, the design of an efficient, modular, and scalable data acquisition and control system is described. It consists of an array of microcontrollers and memories, which feed a single concentrating unit whose information can be accessed by means of a universal series bus (USB) interface to be processed later on. Signal levels can be controlled through a set of digital potentiometers. This system is ideal for experiments with a large number of digital outputs.