Catálogo de publicaciones - revistas

<jats:p>This article surveys results concerning online algorihtms for solving problems related to the management of money and other assets. In particular, the survey focucus us search, replacement, and portfolio selection problems</jats:p>

<jats:p>We survey parallel programming models and languages using six criteria to assess their suitability for realistic portable parallel programming. We argue that an ideal model should by easy to program, should have a software development methodology, should be architecture-independent, should be easy to understand, should guarantee performance, and should provide accurate information about the cost of programs. These criteria reflect our belief that developments in parallelism must be driven by a parallel software industry based on portability and efficiency. We consider programming models in six categories, depending on the level of abstraction they provide. Those that are very abstract conceal even the presence of parallelism at the software level. Such models make software easy to build and port, but efficient and predictable performance is usually hard to achieve. At the other end of the spectrum, low-level models make all of the messy issues of parallel programming explicit (how many threads, how to place them, how to express communication, and how to schedule communication), so that software is hard to build and not very portable, but is usually efficient. Most recent models are near the center of this spectrum, exploring the best tradeoffs between expressiveness and performance. A few models have achieved both abstractness and efficiency. Both kinds of models raise the possibility of parallelism as part of the mainstream of computing.</jats:p>

<jats:p> Search operations in databases require special support at the physical level. This is true for conventional databases as well as spatial databases, where typical search operations include the <jats:italic>point query</jats:italic> (find all objects that contain a given search point) and the <jats:italic>region query</jats:italic> (find all objects that overlap a given search region). More than ten years of spatial database research have resulted in a great variety of multidimensional access methods to support such operations. We give an overview of that work. After a brief survey of spatial data management in general, we first present the class of <jats:italic>point access methods</jats:italic> , which are used to search sets of points in two or more dimensions. The second part of the paper is devoted to <jats:italic>spatial access methods</jats:italic> to handle extended objects, such as rectangles or polyhedra. We conclude with a discussion of theoretical and experimental results concerning the relative performance of various approaches. </jats:p>

<jats:p>After more than 20 years of research and practice in software configuration management (SCM), constructing consistent configurations of versioned software products still remains a challenge. This article focuses on the version models underlying both commercial systems and research prototypes. It provides an overview and classification of different versioning paradigms and defines and relates fundamental concepts such as revisions, variants, configurations, and changes. In particular, we focus on intensional versioning, that is, construction of versions based on configuration rules. Finally, we provide an overview of systems that have had significant impact on the development of the SCM discipline and classify them according to a detailed taxonomy.</jats:p>