Methods for design and evaluation of integrated hardware/software systems for concurrent computation

Two testbed programming environments to support the evaluation of a large range of parallel architectures have been implemented under the program Parallel Implementation of Scientific Computing Environments (PISCES). The PISCES 1 environment was applied to two areas of aerospace interest: a sparse matrix iterative equation solver and a dynamic scene analysis system. Currently, the NICE/SPAR testbed system for structural analysis is being modified for parallel operation under PISCES 2; the PISCES 1 applications are also being adapted for PISCES 2. A new formal model of concurrent computation has been developed, based on the mathematical system known as H graph semantics together with a timed Petri net model of the parallel aspects of a system

Submicron Systems Architecture Project : Semiannual Technical Report

The Mosaic C is an experimental fine-grain multicomputer based on single-chip nodes. The Mosaic C chip includes 64KB of fast dynamic RAM, processor, packet interface, ROM for bootstrap and self-test, and a two-dimensional selftimed router. The chip architecture provides low-overhead and low-latency handling of message packets, and high memory and network bandwidth. Sixty-four Mosaic chips are packaged by tape-automated bonding (TAB) in an 8 x 8 array on circuit boards that can, in turn, be arrayed in two dimensions to build arbitrarily large machines. These 8 x 8 boards are now in prototype production under a subcontract with Hewlett-Packard. We are planning to construct a 16K-node Mosaic C system from 256 of these boards. The suite of Mosaic C hardware also includes host-interface boards and high-speed communication cables. The hardware developments and activities of the past eight months are described in section 2.1. The programming system that we are developing for the Mosaic C is based on the same message-passing, reactive-process, computational model that we have used with earlier multicomputers, but the model is implemented for the Mosaic in a way that supports finegrain concurrency. A process executes only in response to receiving a message, and may in execution send messages, create new processes, and modify its persistent variables before it either exits or becomes dormant in preparation for receiving another message. These computations are expressed in an object-oriented programming notation, a derivative of C++ called C+-. The computational model and the C+- programming notation are described in section 2.2. The Mosaic C runtime system, which is written in C+-, provides automatic process placement and highly distributed management of system resources. The Mosaic C runtime system is described in section 2.3

Activities of the Institute for Computer Applications in Science and Engineering (ICASE)

Research conducted at the Institute for Computer Applications in Science and Engineering in applied mathematics, numerical analysis, and computer science during the period October 1, 1984 through March 31, 1985 is summarized

VIRTUAL MEMORY ON A MANY-CORE NOC

Many-core devices are likely to become increasingly common in real-time and embedded systems as computational demands grow and as expectations for higher performance can generally only be met by by increasing core numbers rather than relying on higher clock speeds. Network-on-chip devices, where multiple cores share a single slice of silicon and employ packetised communications, are a widely-deployed many-core option for system designers. As NoCs are expected to run larger and more complex programs, the small amount of fast, on-chip memory available to each core is unlikely to be sufficient for all but the simplest of tasks, and it is necessary to find an efficient, effective, and time-bounded, means of accessing resources stored in off-chip memory, such as DRAM or Flash storage. The abstraction of paged virtual memory is a familiar technique to manage similar tasks in general computing but has often been shunned by real-time developers because of concern about time predictability. We show it can be a poor choice for a many-core NoC system as, unmodified, it typically uses page sizes optimised for interaction with spinning disks and not solid state media, and transports significant volumes of subsequently unused data across already congested links. In this work we outline and simulate an efficient partial paging algorithm where only those memory resources that are locally accessed are transported between global and local storage. We further show that smaller page sizes add to efficiency. We examine the factors that lead to timing delays in such systems, and show we can predict worst case execution times at even safety-critical thresholds by using statistical methods from extreme value theory. We also show these results are applicable to systems with a variety of connections to memory

Service robotics and machine learning for close-range remote sensing

L'abstract è presente nell'allegato / the abstract is in the attachmen

CLOUD-BASED SOLUTIONS IMPROVING TRANSPARENCY, OPENNESS AND EFFICIENCY OF OPEN GOVERNMENT DATA

A central pillar of open government programs is the disclosure of data held by public agencies using Information and Communication Technologies (ICT). This disclosure relies on the creation of open data portals (e.g. Data.gov) and has subsequently been associated with the expression Open Government Data (OGD). The overall goal of these governmental initiatives is not limited to enhance transparency of public sectors but aims to raise awareness of how released data can be put to use in order to enable the creation of new products and services by private sectors. Despite the usage of technological platforms to facilitate access to government data, open data portals continue to be organized in order to serve the goals of public agencies without opening the doors to public accountability, information transparency, public scrutiny, etc. This thesis considers the basic aspects of OGD including the definition of technical models for organizing such complex contexts, the identification of techniques for combining data from several portals and the proposal of user interfaces that focus on citizen-centred usability. In order to deal with the above issues, this thesis presents a holistic approach to OGD that aims to go beyond problems inherent their simple disclosure by providing a tentative answer to the following questions: 1) To what extent do the OGD-based applications contribute towards the creation of innovative, value-added services? 2) What technical solutions could increase the strength of this contribution? 3) Can Web 2.0 and Cloud technologies favour the development of OGD apps? 4) How should be designed a common framework for developing OGD apps that rely on multiple OGD portals and external web resources? In particular, this thesis is focused on devising computational environments that leverage the content of OGD portals (supporting the initial phase of data disclosure) for the creation of new services that add value to the original data. The thesis is organized as follows. In order to offer a general view about OGD, some important aspects about open data initiatives are presented including their state of art, the existing approaches for publishing and consuming OGD across web resources, and the factors shaping the value generated through government data portals. Then, an architectural framework is proposed that gathers OGD from multiple sites and supports the development of cloud-based apps that leverage these data according to potentially different exploitation roots ranging from traditional business to specialized supports for citizens. The proposed framework is validated by two cloud-based apps, namely ODMap (Open Data Mapping) and NESSIE (A Network-based Environment Supporting Spatial Information Exploration). In particular, ODMap supports citizens in searching and accessing OGD from several web sites. NESSIE organizes data captured from real estate agencies and public agencies (i.e. municipalities, cadastral offices and chambers of commerce) in order to provide citizens with a geographic representation of real estate offers and relevant statistics about the price trend.A central pillar of open government programs is the disclosure of data held by public agencies using Information and Communication Technologies (ICT). This disclosure relies on the creation of open data portals (e.g. Data.gov) and has subsequently been associated with the expression Open Government Data (OGD). The overall goal of these governmental initiatives is not limited to enhance transparency of public sectors but aims to raise awareness of how released data can be put to use in order to enable the creation of new products and services by private sectors. Despite the usage of technological platforms to facilitate access to government data, open data portals continue to be organized in order to serve the goals of public agencies without opening the doors to public accountability, information transparency, public scrutiny, etc. This thesis considers the basic aspects of OGD including the definition of technical models for organizing such complex contexts, the identification of techniques for combining data from several portals and the proposal of user interfaces that focus on citizen-centred usability. In order to deal with the above issues, this thesis presents a holistic approach to OGD that aims to go beyond problems inherent their simple disclosure by providing a tentative answer to the following questions: 1) To what extent do the OGD-based applications contribute towards the creation of innovative, value-added services? 2) What technical solutions could increase the strength of this contribution? 3) Can Web 2.0 and Cloud technologies favour the development of OGD apps? 4) How should be designed a common framework for developing OGD apps that rely on multiple OGD portals and external web resources? In particular, this thesis is focused on devising computational environments that leverage the content of OGD portals (supporting the initial phase of data disclosure) for the creation of new services that add value to the original data. The thesis is organized as follows. In order to offer a general view about OGD, some important aspects about open data initiatives are presented including their state of art, the existing approaches for publishing and consuming OGD across web resources, and the factors shaping the value generated through government data portals. Then, an architectural framework is proposed that gathers OGD from multiple sites and supports the development of cloud-based apps that leverage these data according to potentially different exploitation roots ranging from traditional business to specialized supports for citizens. The proposed framework is validated by two cloud-based apps, namely ODMap (Open Data Mapping) and NESSIE (A Network-based Environment Supporting Spatial Information Exploration). In particular, ODMap supports citizens in searching and accessing OGD from several web sites. NESSIE organizes data captured from real estate agencies and public agencies (i.e. municipalities, cadastral offices and chambers of commerce) in order to provide citizens with a geographic representation of real estate offers and relevant statistics about the price trend