72,097 research outputs found
Route Planning in Transportation Networks
We survey recent advances in algorithms for route planning in transportation
networks. For road networks, we show that one can compute driving directions in
milliseconds or less even at continental scale. A variety of techniques provide
different trade-offs between preprocessing effort, space requirements, and
query time. Some algorithms can answer queries in a fraction of a microsecond,
while others can deal efficiently with real-time traffic. Journey planning on
public transportation systems, although conceptually similar, is a
significantly harder problem due to its inherent time-dependent and
multicriteria nature. Although exact algorithms are fast enough for interactive
queries on metropolitan transit systems, dealing with continent-sized instances
requires simplifications or heavy preprocessing. The multimodal route planning
problem, which seeks journeys combining schedule-based transportation (buses,
trains) with unrestricted modes (walking, driving), is even harder, relying on
approximate solutions even for metropolitan inputs.Comment: This is an updated version of the technical report MSR-TR-2014-4,
previously published by Microsoft Research. This work was mostly done while
the authors Daniel Delling, Andrew Goldberg, and Renato F. Werneck were at
Microsoft Research Silicon Valle
STRUCTURAL DYNAMIC OF THE PUBLIC SECTOR AND MULTILEVEL GOVERNANCE: BETWEEN HIERARCHIES, MARKET AND NETWORK FORMS
In the current economic, social and political context, the problem of the competitiveness reform in public sector lies in the assumption of strategic approaches focused on meeting the public interest, with the lowest cost for society. The philosophy management which governs public sector reform tends to create new paradigms and contributes to shaping a new way of thinking and behavior. Central idea of this paper is that the two dominant models of administration: bureaucracy and governance, provides a range of institutional opportunities but also raises a number of barriers to strategic approaches to emerging public sector. Bureaucracy is for example, criticized because the lack of prioritization skills and lack of goals and also because lacks to stimulate innovation in the public sector. Bureaucracy leads to uniformity, flattening of public services. Governance model contains a number of similarities with the strategic approach in the public sector, when we talk about networks, interdependence and self-organizing nature of public administration. The issue that we are trying reveal to your attention is that the current institutional conditions are more complex than two models mentioned are able to cover. These new demands require the types of organizational structures based on flexible, decentralized structure to replace the traditional centralized, which now is totally inapplicable. Institutional framework may, for example, to provide an opportunity for the New Public Management, but also create a barrier to governance.bureaucracy, governance, public policy, networks, multilevel governance.
Perspects in astrophysical databases
Astrophysics has become a domain extremely rich of scientific data. Data
mining tools are needed for information extraction from such large datasets.
This asks for an approach to data management emphasizing the efficiency and
simplicity of data access; efficiency is obtained using multidimensional access
methods and simplicity is achieved by properly handling metadata. Moreover,
clustering and classification techniques on large datasets pose additional
requirements in terms of computation and memory scalability and
interpretability of results. In this study we review some possible solutions
East-west corporate networking: A theoretical approach
In recent years after the beginning of the transition process, firms in Central and Eastern European countries have been trying hard to find access to international markets and production chains. Rapidly changing institutional, technological and demand conditions together with decades of isolation from world markets do not let ,,stand-alone strategies appear very successful in this context. The paper presents networking activities as a promising alternative for Central and Eastern European firms (CEEF) to organize international transactions. As several theories show, network forms of organization can - by establishing an atmosphere of trust and stability and by pooling resources and information - make it possible for network members to realize an economic advantage over external competitors that is higher than in markets or hierarchies. Among various types of networking activities, it is especially long-term-orientated relations that offer the possibility for CEEF to participate in an international exchange of crucial technologies and to upgrade their position in global production chains in the long run.
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