39 research outputs found
Spatial structure and temporal dynamics of the human occupation of Neuquén (Argentinian Patagonia) during the late Pleistocene-Holocene
Se generó una base de datos conformada por 184 fechados georeferenciados procedentes de sitios arqueológicos de la provincia del Neuquén. Doce de estos fechados -realizados a partir de restos óseos humanos y faunísticos- son originales y corresponden, algunos de ellos, a áreas geográficas para las que aún no se contaba con datos. Se efectuaron análisis cuantitativos temporo-espaciales. Los resultados obtenidos sobre la base de datos cronológicos y geográficos permiten caracterizar el proceso de ocupación humana de Neuquén como temprano, mayormente continuo a lo largo del tiempo y espacialmente discontinuo. La profundidad temporal del poblamiento alcanza ca. 12.000 años calibrados AP y la ocupación del espacio se incrementa significativamente hacia el Holoceno tardío. La distribución espacial de los sitios es discontinua y muestra concentraciones en áreas particulares cercanas a los cursos de agua permanente, mayoritariamente peri-cordilleranas, en tanto que en los espacios intermedios -las amplias planicies del este- no se registró una señal arqueológica marcada.A database was generated consisting of 184 georeferenced dates from archaeological sites in Neuquén Province. Twelve of these dates −taken from human and faunal bone remains− are original, and some correspond to geographical areas for which data were not previously available. Quantitative spatial-temporal analyzes were carried out. The results obtained on the basis of chronological and geographical data allow Neuquén’s human occupation process to be characterized as early, mostly continuous over time, and spatially discontinuous. The temporal depth of the settlement reaches ca. 12,000 years BP calibrated, with spacial occupation increasing significantly towards the late Holocene. The spatial distribution of the sites is discontinuous and shows concentrations in particular areas near the permanent water courses, mostly near the Andes, while in the intermediate spaces −the wide plains of the east− a marked archaeological signal was not recorded.Fil: Gordón, Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Beguelin, Marien. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Rindel, Diego Damián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; ArgentinaFil: Della Negra, Claudia Eugenia. No especifíca;Fil: Hajduk, Adam. Administración de Parques Nacionales. Museo de la Patagonia "Francisco Perito Moreno"; ArgentinaFil: Vazquez, Romina Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Cobos, Virginia Agustina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Perez, Sergio Ivan. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Bernal, Valeria. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin
A Users' Guide to PVM . . .
PVM and a list of available files in the package will be returned. The source files, which consume less than 350Kbytes, are available in the shar file pvm shar. To receive this file send the message: send pvmshar from pvm The space requirement for PVM depends on the number of architectures for which it is built. A set up for five different architectures requires about 1 Mbyte of disk space. 6. Reference
Xab: A Tool for Monitoring PVM Programs
Xab (X-window Analysis and deBugging) is a tool for run time monitoring of PVM (Parallel Virtual Machine) programs. PVM supports the programming of a network of heterogeneous computers as a single parallel computer. Using Xab, PVM programs can easily be instrumented and monitored. Xab uses PVM to monitor PVM programs. This makes Xab very portable but it leads to interesting issues of how to make Xab peacefully coincide with the programs it monitors. Xab consists of three main components, a user library, a monitoring program, and an X windows front end. The user library provides instrumented versions of the PVM calls. The monitoring program runs as a PVM process and gathers monitor events in the form of PVM messages. The Xab front end displays information graphically about PVM processes and messages. This paper discusses the design, implementation, and use of the Xab tool. Related work is briefly presented and contrasted with the approach taken with Xab. How Xab works and how it is use..
Causality-Preserving Timestamps in Distributed Programs
A tachyon is an improperly ordered event in a distributed program. Tachyons are most often manifested as messages which are received before they are sent, violating the principle of causality. Although tachyons are not possible in "real life", they may appear to occur in distributed parallel program traces due to coarse clock granularity or poor clock synchronization. In this paper, we establish that tachyons do in fact occur commonly in distributed programs on our Ethernet at Carnegie Mellon University, and we discuss some ways of eliminating them from program traces while preserving at least some knowledge of the length of time intervals in our programs. Our methods are based on Lamport-style clock corrections; when a process receives a message stamped with a later sending time, it sets its own clock ahead to a time at least as great as the sending timestamp. We have implemented this both in real time and in a more comprehensive post-processor for Xab. 1 Introduction When writing ..
High-Level Fault Tolerance in Distributed Programs
We have been developing high-level checkpoint and restart methods for Dome (Distributed Object Migration Environment) , a C++ library of data-parallel objects that are automatically distributed using PVM. There are several levels of programming abstraction at which fault tolerance mechanisms can be designed: high-level, where the checkpoint and restart are built into our C++ objects, but the program structure is severly constrained; high-level with preprocessing, where a preprocessor inserts extra C++ statements into the code to facilitate checkpoint and restart; and low-level, where periodically an interrupt causes a memory image to be written out. Because we consider portability (both of our libraries and of the checkpoints they produce) to be an important goal, we focus on the higher-level checkpointing methods. In addition, we describe an implementation of high-level checkpointing, demonstrate it on multiple architectures, and show that it is efficient enough to provide good expect..
Visual Parallel Programming and Determinacy: A Language Specification, an Analysis Technique, and a Programming Tool
Phred is a visual parallel programming language in which programs can be statically analyzed for deterministic behavior. This paper presents the Phred language, techniques for analyzing the language, and a programming environment which supports Phred programming. There are many methods for specifying synchronization and data sharing in parallel programs. The Phred programmer uses graph constructs for describing parallelism, synchronization and data sharing. These graphs are formally described in this paper as a graph grammar. The use of graphs in Phred provides an intuitive and visual representation for parallel computations. The inadvertent specification of nondeterministic computations is a common error in parallel programming. Phred addresses the issue of determinacy by visually indicating regions of a program where nondeterminacy may exist. This analysis and its integration into a programming environment is presented here. The Phred programming environment supports the specificatio..
Process Groups for Distributed Computing
PVM (Parallel Virtual Machine) assigns a single task identification (tid) to each process running on the distributed virtual machine. The tid encodes a machine identification and in the case of a multiprocessor machine, a node identification. Tid's are assigned in such a way that processes may be spawned locally with the local message routing process (pvmd) notifying the other pvmd's after the process addition. While this is a useful and convenient method from a systems view, it does not provide a sufficiently high level of abstraction for programmers who often prefer a 0 -- N naming scheme for spawned processes. PVM3 uses the notion of process groups to simplify the naming problem. Groups are implemented in a central server process that maps group names to (instance,tid) pairs and provides a mechanism for collective communications. Group membership is allowed to undergo changes during a program run and are termed dynamic. This ability can be especially important for long term calculat..
ECO: Efficient Collective Operations for Communication on Heterogeneous Networks
PVM and other distributed computing systems have enabled the use of networks of workstations for parallel computation, but their approach of treating a network as a collection of point-to-point connections does not promote efficient communication--- particularly collective communication. ECO is a package which solves this problem with programs which analyze the network and establish efficient communication patterns which are used by a library of collective operations. The analysis is done off-line, so that after paying the one-time cost of analyzing the network, the execution of application programs is not delayed. This paper gives performance results from using ECO to implement the collective communication in CHARMM, a widely used macromolecular dynamics package. ECO facilitates the development of data parallel applications by providing a simple interface to routines which use the available heterogeneous networks efficiently. This approach gives a naive programmer the abili..