61,232 research outputs found
Governance of regional innovations towards sustainability
This paper addresses the governance of regional innovations towards sustainability. From the literature it is clear that variety is a major source of innovations: innovations come into being in interplay between a variety of public and private actors who bring with them a large variety of identities, values, realities and practices. In this context, traditional concepts of governance such as planning and control, formalized processes and top–down steering are less appropriate. Yet some stability and structures are needed to create common understandings and mutual trust
The VITI program: Final Report
In this report we present our findings and results from the
VITI program in 2000. The focus of the research work undertaken by
VITI has been to provide electronic meeting environments that are easy
to use and afford as natural a collaboration experience as
possible. This final report is structured into three parts. Part one
concerns the VITI infrastructure and consists of two sections. The
first section describes the process of establishing the
infrastructure, concentrating on how the work was done. The second
section presents the actual infrastructure that is in place today,
concentrating on what has been put in place. Part two examines the use
the VITI infrastructure has been put to, giving examples of activities
it has supported and discussing strengths and weaknesses that have
emerged through this use. Finally part three considers the future of
distributed electronic meeting environments. It is recommended that
the report be read in the order in which it is presented. However,
each section has been written as a standalone document and can be read
independently of the others
Analysis, classification and comparison of scheduling techniques for software transactional memories
Transactional Memory (TM) is a practical programming paradigm for developing concurrent applications. Performance is a critical factor for TM implementations, and various studies demonstrated that specialised transaction/thread scheduling support is essential for implementing performance-effective TM systems. After one decade of research, this article reviews the wide variety of scheduling techniques proposed for Software Transactional Memories. Based on peculiarities and differences of the adopted scheduling strategies, we propose a classification of the existing techniques, and we discuss the specific characteristics of each technique. Also, we analyse the results of previous evaluation and comparison studies, and we present the results of a new experimental study encompassing techniques based on different scheduling strategies. Finally, we identify potential strengths and weaknesses of the different techniques, as well as the issues that require to be further investigated
emgr - The Empirical Gramian Framework
System Gramian matrices are a well-known encoding for properties of
input-output systems such as controllability, observability or minimality.
These so-called system Gramians were developed in linear system theory for
applications such as model order reduction of control systems. Empirical
Gramian are an extension to the system Gramians for parametric and nonlinear
systems as well as a data-driven method of computation. The empirical Gramian
framework - emgr - implements the empirical Gramians in a uniform and
configurable manner, with applications such as Gramian-based (nonlinear) model
reduction, decentralized control, sensitivity analysis, parameter
identification and combined state and parameter reduction
Antares: A low cost modular launch vehicle for the future
The single-stage-to-orbit launch vehicle Antares is a revolutionary concept based on identical modular units, enabling the Antares to efficiently launch communications satellites, as well as heavy payloads, into Earth orbit and beyond. The basic unit of the modular system, a single Antares vehicle, is aimed at launching approximately 10,000 kg (22,000 lb) into low Earth orbit (LEO). When coupled with a standard Centaur upper stage, it is capable of placing 4000 kg (8800 lb) into geosynchronous Earth orbit (GE0). The Antares incorporates a reusable engine, the Dual Mixture Ratio Engine (DMRE), as its propulsive device. This enables Antares to compete and excel in the satellite launch market by dramatically reducing launch costs. Inherent in the design is the capability to attach several of these vehicles together to provide heavy lift capability. Any number of these vehicles can be attached depending on the payload and mission requirements. With a seven-vehicle configuration, the Antares' modular concept provides a heavy lift capability of approximately 70,000 kg (154,000 lb) to LEO. This expandability allows for a wide range of payload options, such as large Earth satellites, Space Station Freedom material, and interplanetary spacecraft, and also offers a significant cost savings over a mixed fleet based on different launch vehicles
- …