14,172 research outputs found
Merlin: A Language for Provisioning Network Resources
This paper presents Merlin, a new framework for managing resources in
software-defined networks. With Merlin, administrators express high-level
policies using programs in a declarative language. The language includes
logical predicates to identify sets of packets, regular expressions to encode
forwarding paths, and arithmetic formulas to specify bandwidth constraints. The
Merlin compiler uses a combination of advanced techniques to translate these
policies into code that can be executed on network elements including a
constraint solver that allocates bandwidth using parameterizable heuristics. To
facilitate dynamic adaptation, Merlin provides mechanisms for delegating
control of sub-policies and for verifying that modifications made to
sub-policies do not violate global constraints. Experiments demonstrate the
expressiveness and scalability of Merlin on real-world topologies and
applications. Overall, Merlin simplifies network administration by providing
high-level abstractions for specifying network policies and scalable
infrastructure for enforcing them
Solving weighted and counting variants of connectivity problems parameterized by treewidth deterministically in single exponential time
It is well known that many local graph problems, like Vertex Cover and
Dominating Set, can be solved in 2^{O(tw)}|V|^{O(1)} time for graphs G=(V,E)
with a given tree decomposition of width tw. However, for nonlocal problems,
like the fundamental class of connectivity problems, for a long time we did not
know how to do this faster than tw^{O(tw)}|V|^{O(1)}. Recently, Cygan et al.
(FOCS 2011) presented Monte Carlo algorithms for a wide range of connectivity
problems running in time $c^{tw}|V|^{O(1)} for a small constant c, e.g., for
Hamiltonian Cycle and Steiner tree. Naturally, this raises the question whether
randomization is necessary to achieve this runtime; furthermore, it is
desirable to also solve counting and weighted versions (the latter without
incurring a pseudo-polynomial cost in terms of the weights).
We present two new approaches rooted in linear algebra, based on matrix rank
and determinants, which provide deterministic c^{tw}|V|^{O(1)} time algorithms,
also for weighted and counting versions. For example, in this time we can solve
the traveling salesman problem or count the number of Hamiltonian cycles. The
rank-based ideas provide a rather general approach for speeding up even
straightforward dynamic programming formulations by identifying "small" sets of
representative partial solutions; we focus on the case of expressing
connectivity via sets of partitions, but the essential ideas should have
further applications. The determinant-based approach uses the matrix tree
theorem for deriving closed formulas for counting versions of connectivity
problems; we show how to evaluate those formulas via dynamic programming.Comment: 36 page
A symbolic semantics for a clculus for service-oriented computing
We introduce a symbolic characterisation of the operational semantics of COWS, a formal language for specifying and combining service-oriented applications, while modelling their dynamic behaviour. This alternative semantics avoids infinite representations of COWS terms due to the value-passing nature of communication in COWS and is more amenable for automatic manipulation by analytical tools, such as e.g. equivalence and model checkers. We illustrate our approach through a âtranslation serviceâ scenario
Security Toolbox for Detecting Novel and Sophisticated Android Malware
This paper presents a demo of our Security Toolbox to detect novel malware in
Android apps. This Toolbox is developed through our recent research project
funded by the DARPA Automated Program Analysis for Cybersecurity (APAC)
project. The adversarial challenge ("Red") teams in the DARPA APAC program are
tasked with designing sophisticated malware to test the bounds of malware
detection technology being developed by the research and development ("Blue")
teams. Our research group, a Blue team in the DARPA APAC program, proposed a
"human-in-the-loop program analysis" approach to detect malware given the
source or Java bytecode for an Android app. Our malware detection apparatus
consists of two components: a general-purpose program analysis platform called
Atlas, and a Security Toolbox built on the Atlas platform. This paper describes
the major design goals, the Toolbox components to achieve the goals, and the
workflow for auditing Android apps. The accompanying video
(http://youtu.be/WhcoAX3HiNU) illustrates features of the Toolbox through a
live audit.Comment: 4 pages, 1 listing, 2 figure
OPTIMAL AREA AND PERFORMANCE MAPPING OF K-LUT BASED FPGAS
FPGA circuits are increasingly used in many fields: for rapid prototyping of new products (including fast ASIC implementation), for logic emulation, for producing a small number of a device, or if a device should be reconfigurable in use (reconfigurable computing). Determining if an arbitrary, given wide, function can be implemented by a programmable logic block, unfortunately, it is generally, a very difficult problem. This problem is called the Boolean matching problem. This paper introduces a new implemented algorithm able to map, both for area and performance, combinational networks using k-LUT based FPGAs.k-LUT based FPGAs, combinational circuits, performance-driven mapping.
Dynamic Programming for Graphs on Surfaces
We provide a framework for the design and analysis of dynamic programming
algorithms for surface-embedded graphs on n vertices and branchwidth at most k.
Our technique applies to general families of problems where standard dynamic
programming runs in 2^{O(k log k)} n steps. Our approach combines tools from
topological graph theory and analytic combinatorics. In particular, we
introduce a new type of branch decomposition called "surface cut
decomposition", generalizing sphere cut decompositions of planar graphs
introduced by Seymour and Thomas, which has nice combinatorial properties.
Namely, the number of partial solutions that can be arranged on a surface cut
decomposition can be upper-bounded by the number of non-crossing partitions on
surfaces with boundary. It follows that partial solutions can be represented by
a single-exponential (in the branchwidth k) number of configurations. This
proves that, when applied on surface cut decompositions, dynamic programming
runs in 2^{O(k)} n steps. That way, we considerably extend the class of
problems that can be solved in running times with a single-exponential
dependence on branchwidth and unify/improve most previous results in this
direction.Comment: 28 pages, 3 figure
Paradigm Innovation through the Strategic Collaboration between TORAY & UNIQLO : Evolution of A New Fast Fashion Business Model
The key purpose of this study is to examine the remarkable context within the evolution of the paradigm innovation in fashion product development, in the case of Japanese fashion apparel, UNIQLO, created by Fast Retailing Corp in 1998. The key theme hereby concerns innovation, and this perspective surely necessitates Fast Retailing's strategic collaboration with a Japanese new material and artificial textile powerhouse, TORAY: as TORAY's technological provision was an essential source for the dynamic product and process innovation behind the extraordinary growth of UNIQLO. Furthermore, the technological superiority also entailed its innovative positioning in market competition. It is crucial to examine how and why the two brought about their core competences together through new combinations of concepts. This should impart a few promising research perspectives regarding their innovative model of unchallenged value creation, strong market competitiveness, and sustainable corporate growth.Paradigm Innovation, Product Development, Business Model, Japanese Apparel Industry, Fashion Apparel, Fast Fashion, Fast Retailing, UNIQLO, TORAY, Alliance, Virtual Vertical Integration
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