Criteria for evaluation of reflective surface for parabolic dish concentrators

Commercial, second surface glass mirror are emphasized, but aluminum and metallized polymeric films are also included. Criteria for sealing solar mirrors in order to prevent environmental degradation and criteria for bonding sagged or bent mirrors to substrate materials are described. An overview of the technical areas involved in evaluating small mirror samples, sections, and entire large gores is presented. A basis for mirror criteria was established that eventually may become part of inspection and evaluation techniques for three dimensional parabolic reflective surfaces

Enabling Distributed Knowledge Management: Managerial and Technological Implications

In this paper we show that the typical architecture of current KM systems re.ects an objectivistic epistemology and a traditional managerial control paradigm. We argue that such an objectivistic epistemology is inconsistent with many theories on the nature of knowledge, in which subjectivity and sociality are taken as essential features of knowledge creation and sharing. We show that adopting such a new epistemological view has dramatic consequences at an architectural, managerial and technological level

Knowledge Nodes: the Building Blocks of a Distributed Approach to Knowledge Management

Abstract: In this paper we criticise the objectivistic approach that underlies most current systems for Knowledge Management. We show that such an approach is incompatible with the very nature of what is to be managed (i.e., knowledge), and we argue that this may partially explain why most knowledge management systems are deserted by users. We propose a different approach - called distributed knowledge management - in which subjective and social (in a word, contextual) aspects of knowledge are seriously taken into account. Finally, we present a general technological architecture in which these ideas are implemented by introducing the concept of knowledge node

Exact and approximate strategies for symmetry reduction in model checking

Symmetry reduction techniques can help to combat the state space explosion problem for model checking, but are restricted by the hard problem of determining equivalence of states during search. Consequently, existing symmetry reduction packages can only exploit full symmetry between system components, as checking the equivalence of states is straightforward in this special case. We present a framework for symmetry reduction with an arbitrary group of structural symmetries. By generalising existing techniques for efficiently exploiting symmetry, and introducing an approximate strategy for use with groups for which fast, exact strategies are not available, our approach allows for significant state-space reduction with minimal time overhead. We show how computational group theoretic techniques can be used to analyse the structure of a symmetry group so that an appropriate symmetry reduction strategy can be chosen, and we describe a symmetry reduction package for the Spin model checker which interfaces with the computational algebra system Gap. Experimental results on a variety of Promela models illustrate the effectiveness of our methods

Peer - Mediated Distributed Knowledge Management

Distributed Knowledge Management is an approach to knowledge management based on the principle that the multiplicity (and heterogeneity) of perspectives within complex organizations is not be viewed as an obstacle to knowledge exploitation, but rather as an opportunity that can foster innovation and creativity. Despite a wide agreement on this principle, most current KM systems are based on the idea that all perspectival aspects of knowledge should be eliminated in favor of an objective and general representation of knowledge. In this paper we propose a peer-to-peer architecture (called KEx), which embodies the principle above in a quite straightforward way: (i) each peer (called a K-peer) provides all the services needed to create and organize "local" knowledge from an individual's or a group's perspective, and (ii) social structures and protocols of meaning negotiation are introduced to achieve semantic coordination among autonomous peers (e.g., when searching documents from other K-peers). A first version of the system, called KEx, is imple-mented as a knowledge exchange level on top of JXTA