Efficient methods for solving multi-rate partial differential equations in radio frequency applications

In telecommunication electronics, radio frequency applications are usually characterized by widely separated time scales. This multi-rate behavior arises in many kinds of circuits and increases considerably the computation costs of numerical simulations. In this paper we are mainly interested in electronic circuits driven by envelope modulated signals and we will show that the application of numerical methods based on a multi-rate partial differential equation analysis will lead to an efficient strategy for simulating this type of problems

Numerical Simulation of Electronic Systems Based on Circuit- Block Partitioning Strategies

Numerical simulation of complex and heterogeneous electronic systems can be a very challenging issue. Circuits composed of a combination of analog, mixed-signal and digital blocks or even radio frequency (RF) blocks, integrated in the same substrate, are very difficult to simulate as a whole at the circuit level. The main reason is because they contain a lot of state variables presenting very distinct properties and evolving in very widely separated time scales. Examples of practical interest are systems-on-a-chip (SoCs), very common in mobile electronics applications, as well as in many other embedded electronic systems. This chapter is intended to briefly review some advanced circuit-level numerical simulation techniques based on circuit-block partitioning schemes, which were especially designed to address the simulation challenges brought by this kind of circuits into the computer-aided-design (CAD) field

Prioritization of railway proximity interventions: The case of the Portuguese railway network

The mission of a national railway administration is to provide conditions for the efficiency, competitiveness, and sustainability of rail transport. In this context, this study aims to fill a gap in rail infrastructure management through the adoption of multi-criteria decision analysis (MCDA) and quadrant analysis to obtain a priority evaluation matrix for railway proximity interventions (small-scale, medium/short-term interventions close to the customer). In order to achieve the network manager’s general goals, an extensive collection of railway activities and an iterative procedure, which combines the strategic vision of different operational units, were adopted. Moreover, a multi-criteria and hierarchy process based on quadrant analysis to select the interventions with greater potential to achieve a set of objectives over five years, was defined. The proposed methodology was applied in a real case within the Infrastructures of Portugal, SA competencies and needs (Portuguese railway network manager). The identification of a set of fundamental interventions from a technical and non-technical point of view was performed and allowed a more efficient resource allocation. This allowed listing the most relevant interventions in both technical and non-technical perspectives (19–25% of total interventions) and also from an essentially technical point of view (27–31% of total interventions). These correspond to the interventions located in the two most relevant quadrants (Q1 – develop and Q2 – validate) and to more than 70% of the total investment. The presented approach and results constitute the first three iterations to be monitored and evaluated in the revision of future plans in order to increase reliability levels, safety conditions and service quality. The methodology has the potential to be adapted to different scenarios (in particular budgetary) and future proximity intervention plans, thus being an essential decision support tool for an efficient allocation of the company’s resources.info:eu-repo/semantics/publishedVersio

Development and validation of a multiplex-PCR assay for X-linked intellectual disability

BACKGROUND: X-linked intellectual disability is a common cause of inherited cognitive deficit affecting mostly males. There are several genetic causes implicated in this condition, which has hampered the establishment of an accurate diagnosis. We developed a multiplex-PCR assay for the mutational hotspot regions of the FMR1, AFF2 and ARX genes. METHODS: The multiplex-PCR was validated in a cohort of 100 males selected to include known alleles for the FMR1 repetitive region: five full mutations (250-650 CGGs), ten premutations (70-165 CGGs) and eighty-five in the normal range (19-42 CGGs). Sequencing or Southern blotting was used to confirm the results, depending on the allele class. In this cohort, with the exception of one sample showing an AFF2 intermediate-sized allele, all other samples were normal (8-34 CCGs). No ARX variant was found besides the c.429_452dup. The validated assay was applied to 5000 samples (64.4% males and 35.6% females). RESULTS: The normal-allelic range of both FMR1 and AFF2 genes as well as the nature of ARX variants identified was similar in both genders. The rate of homozygosity observed in female samples, 27.5% for FMR1 and 17.8% for AFF2 alleles, is comparable to that published by others. Two FMR1 premutations were identified, in a male (58 CGGs) and a female case [(CGG)(47)/(CGG)(61)], as well as several FMR1 or AFF2 intermediate-sized alleles. One AFF2 premutation (68 CCGs) and two putative full expansions were picked up in male subjects, which seems relevant considering the rarity of reported AFF2 mutations found in the absence of a family history. CONCLUSIONS: We developed a robust multiplex-PCR that can be used to screen the mutational hotspot regions of FMR1, AFF2 and ARX genes. Moreover, this strategy led to the identification of variants in all three genes, representing not only an improvement in allele-sizing but also in achieving a differential diagnosis. Although the distinction between females who are truly homozygous and those with a second pre- or full mutation sized allele, as well as a definitive diagnosis, requires a specific downstream technique, the use of this multiplex-PCR for initial screening is a cost-effective approach which widens the scope of detection

POSSIBILIDADES DA EDUCAÇÃO FÍSICA NA FORMAÇÃO DO TRABALHADOR

O tema da educação pública tem ocupado amplos espaços nos meios de comunicação na atualidade. Aspectos como qualidade do ensino ministrado, universalização do acesso à escola, preparação para o trabalho e etc., têm sido utilizados para explicar parte do problema do desemprego, da disseminação da violência, da pobreza, como uma explicação baseada nos pressupostos da Teoria do Capital Humano

Envelope transient simulation of nonlinear electronic circuits using multi-rate Runge-Kutta algorithms

Time-step integration is a popular technique commonly used for the envelope transient simulation of an electronic circuit. However, many kinds of circuits are characterized by widely separated time scales, which lead to significant computational costs when numerically solving its differential systems. Even so, this situation can be exploited in an efficient way using multi-rate methods, which integrate system components with different step sizes. In this paper two multi-rate Runge-Kutta schemes are studied and tested in terms of computational speed and numerical stability. The results for linear stability analysis here obtained are much more coherent with the characteristics of the methods than the ones previously presented in [6]

LegOSC : mindstroms NXT robotics programming for artists

Robotics is an interesting but difficult area for digital artists who generally don’t have much academic background on electronics or computer programming. Digital art students normally use high-level application to program their visual and sonorous installations. This paper presents LegOSC - a tool that allows the control of the Mindstorms NXT robots from any application that uses the Open Sound Control protocol which is implemented by most of those high-level applications. This allows artists to create works which incorporate robotic parts using the familiar programming environment