Director Emeritus

Bio: Director Emeritus is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 1160 citations.

Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)

Abstract: IN 1974, the International Radiation Protection Association (IRPA) formed a working group on non-ionizing radiation (NIR), which examined the problems arising in the field of protection against the various types of NIR. At the IRPA Congress in Paris in 1977, this working group became the International Non-Ionizing Radiation Committee (INIRC). In cooperation with the Environmental Health Division of the World Health Organization (WHO), the IRPA/INIRC developed a number of health criteria documents on NIR as part of WHO’s Environmental Health Criteria Programme, sponsored by the United Nations Environment Programme (UNEP). Each document includes an overview of the physical characteristics, measurement and instrumentation, sources, and applications of NIR, a thorough review of the literature on biological effects, and an evaluation of the health risks of exposure to NIR. These health criteria have provided the scientific database for the subsequent development of exposure limits and codes of practice relating to NIR. At the Eighth International Congress of the IRPA (Montreal, 18–22 May 1992), a new, independent scientific organization—the International Commission on Non-Ionizing Radiation Protection (ICNIRP)—was established as a successor to the IRPA/INIRC. The functions of the Commission are to investigate the hazards that may be associated with the different forms of NIR, develop international guidelines on NIR exposure limits, and deal with all aspects of NIR protection. Biological effects reported as resulting from exposure to static and extremely-low-frequency (ELF) electric and magnetic fields have been reviewed by UNEP/ WHO/IRPA (1984, 1987). Those publications and a number of others, including UNEP/WHO/IRPA (1993) and Allen et al. (1991), provided the scientific rationale for these guidelines. A glossary of terms appears in the Appendix.

Model-Driven Software Engineering in Practice

Abstract: This book discusses how model-based approaches can improve the daily practice of software professionals. This is known as Model-Driven Software Engineering (MDSE) or, simply, Model-Driven Engineering (MDE). MDSE practices have proved to increase efficiency and effectiveness in software development, as demonstrated by various quantitative and qualitative studies. MDSE adoption in the software industry is foreseen to grow exponentially in the near future, e.g., due to the convergence of software development and business analysis. The aim of this book is to provide you with an agile and flexible tool to introduce you to the MDSE world, thus allowing you to quickly understand its basic principles and techniques and to choose the right set of MDSE instruments for your needs so that you can start to benefit from MDSE right away. The book is organized into two main parts. The first part discusses the foundations of MDSE in terms of basic concepts (i.e., models and transformations), driving principles, application scenarios and current standards, like the well-known MDA initiative proposed by OMG (Object Management Group) as well as the practices on how to integrate MDSE in existing development processes. The second part deals with the technical aspects of MDSE, spanning from the basics on when and how to build a domain-specific modeling language, to the description of Model-to-Text and Model-to-Model transformations, and the tools that support the management of MDSE projects. The book is targeted to a diverse set of readers, spanning: professionals, CTOs, CIOs, and team managers that need to have a bird's eye vision on the matter, so as to take the appropriate decisions when it comes to choosing the best development techniques for their company or team; software analysts, developers, or designers that expect to use MDSE for improving everyday work productivity, either by applying the basic modeling techniques and notations or by defining new domain-specific modeling languages and applying end-to-end MDSE practices in the software factory; and academic teachers and students to address undergrad and postgrad courses on MDSE. In addition to the contents of the book, more resources are provided on the book's website http://www.mdse-book.com/, including the examples presented in the book. Table of Contents: Introduction / MDSE Principles / MDSE Use Cases / Model-Driven Architecture (MDA) / Integration of MDSE in your Development Process / Modeling Languages at a Glance / Developing your Own Modeling Language / Model-to-Model Transformations / Model-to-Text Transformations / Managing Models / Summary

Pericentrin and gamma-tubulin form a protein complex and are organized into a novel lattice at the centrosome.

Abstract: Pericentrin and γ-tubulin are integral centrosome proteins that play a role in microtubule nucleation and organization. In this study, we examined the relationship between these proteins in the cytoplasm and at the centrosome. In extracts prepared from Xenopus eggs, the proteins were part of a large complex as demonstrated by sucrose gradient sedimentation, gel filtration and coimmunoprecipitation analysis. The pericentrin–γ-tubulin complex was distinct from the previously described γ-tubulin ring complex (γ-TuRC) as purified γ-TuRC fractions did not contain detectable pericentrin. When assembled at the centrosome, the two proteins remained in close proximity as shown by fluorescence resonance energy transfer. The three- dimensional organization of the centrosome-associated fraction of these proteins was determined using an improved immunofluorescence method. This analysis revealed a novel reticular lattice that was conserved from mammals to amphibians, and was organized independent of centrioles. The lattice changed dramatically during the cell cycle, enlarging from G1 until mitosis, then rapidly disassembling as cells exited mitosis. In cells colabeled to detect centrosomes and nucleated microtubules, lattice elements appeared to contact the minus ends of nucleated microtubules. Our results indicate that pericentrin and γ-tubulin assemble into a unique centrosome lattice that represents the higher-order organization of microtubule nucleating sites at the centrosome.

Multilevel converters for single-phase grid connected photovoltaic systems-an overview

Abstract: Multilevel voltage source inverters offer several advantages compared to their conventional counterparts. By synthesising the AC output terminal voltage from several levels of voltages, staircase waveforms can be produced, which approach the sinusoidal waveform with low harmonic distortion, thus reducing filter requirements. The need of several sources on the DC side of the converter makes multilevel technology attractive for photovoltaic applications. This paper provides an overview an different multilevel topologies and investigates their suitability for single-phase grid connected photovoltaic systems. Several transformerless photovoltaic systems incorporating multilevel converters are compared regarding issues such as component count and stress, system power rating and the influence of the photovoltaic array earth capacitance.

Requirements Elicitation: A Survey of Techniques, Approaches, and Tools

Abstract: Requirements elicitation is the process of seeking, uncovering, acquiring, and elaborating requirements for computer based systems. It is generally understood that requirements are elicited rather than just captured or collected. This implies there are discovery, emergence, and development elements in the elicitation process. Requirements elicitation is a complex process involving many activities with a variety of available techniques, approaches, and tools for performing them. The relative strengths and weaknesses of these determine when each is appropriate depending on the context and situation. The objectives of this chapter are to present a comprehensive survey of important aspects of the techniques, approaches, and tools for requirements elicitation, and examine the current issues, trends, and challenges faced by researchers and practitioners in this field.