Search results for "Theoretical Computer Science"
showing 10 items of 1151 documents
Fully Dynamic Evaluation of Sequence Pair
2013
In the electronic design automation field, as well as in other areas, problem instances and solutions are often subject to discrete changes. The foundational significance of efficient updates of the criterion value after dynamic updates, instead of recomputing it from scratch each time, has attracted a lot of research. In this paper, motivated by the significance of the sequence pair (SP) representation for floorplanning, we develop a fully dynamic algorithm of SP evaluation, that efficiently updates a criterion value after insertions and deletions of SP elements and after modifications of element weights. Our result is based on a new data structure for the predecessor problem, which mainta…
Lightweight algorithms for constructing and inverting the BWT of string collections
2013
Recent progress in the field of \{DNA\} sequencing motivates us to consider the problem of computing the Burrows‚ÄìWheeler transform (BWT) of a collection of strings. A human genome sequencing experiment might yield a billion or more sequences, each 100 characters in length. Such a dataset can now be generated in just a few days on a single sequencing machine. Many algorithms and data structures for compression and indexing of text have the \{BWT\} at their heart, and it would be of great interest to explore their applications to sequence collections such as these. However, computing the \{BWT\} for 100 billion characters or more of data remains a computational challenge. In this work we ad…
A hybrid approach to semantic web services matchmaking
2008
AbstractDeploying the semantics embedded in web services is a mandatory step in the automation of discovery, invocation and composition activities. The semantic annotation is the “add-on” to cope with the actual interoperability limitations and to assure a valid support to the interpretation of services capabilities. Nevertheless many issues have to be reached to support semantics in the web services and to guarantee accurate functionality descriptions. Early efforts address automatic matchmaking tasks, in order to find eligible advertised services which appropriately meet the consumer’s demand. In the most of approaches, this activity is often entrusted to software agents, able to drive re…
Building a medical research cloud in the EASI-CLOUDS project
2015
Summary The demand for Information Technology (IT) resources is constantly growing in the scientific area. The ability to store and process increasing amounts of data has transformed many research disciplines like the life sciences, which now rely on complex data processing and data analytics. Cloud computing can provide researchers with scalable and easy-to-use hardware and software resources and allows on-demand access to services, tools, or even complete work environments. The European research project EASI-CLOUDS has developed a service delivery platform with special regard to service integration, monitoring and management, and the negotiation of service level agreements. In order to de…
Privacy-preserving data allocation in decentralized online social networks
2016
International audience; Distributed Online Social Networks (DOSNs) have been recently proposed as an alternative to centralized solutions to allow a major control of the users over their own data. Since there is no centralized service provider which decides the term of service, the DOSNs infrastructure exploits users’ devices to take on the online social network services. In this paper, we propose a data allocation strategy for DOSNs which exploits the privacy policies of the users to increase the availability of the users’ contents without diverging from their privacy preferences. A set of replicas of the profile’s content of a user U are stored on the devices of other users who are entitl…
On the number of factors of Sturmian words
1991
Abstract We prove that for m ⩾1, card( A m ) = 1+∑ m i =1 ( m − i +1) ϕ ( i ) where A m is the set of factors of length m of all the Sturmian words and ϕ is the Euler function. This result was conjectured by Dulucq and Gouyou-Beauchamps (1987) who proved that this result implies that the language (∪ m ⩾0 A m ) c is inherently ambiguous. We also give a combinatorial version of the Riemann hypothesis.
A multiple layered functional data model to support multiple representations and interoperability of GIS
2001
This paper presents a multi-layered functional data model to support multiple representation and information sharing among distributed spatial information systems. The key idea is that a geographical space (foe example an urban space) can be viewed as a set of abstract spatial functionalities on which different application classes can be derived to manipulate objects of the same geographical space and share the same abstract generic functionalities. The object classes define multiple views or representations of a domain. For example in urban management, transportation systems, water supply and sewage systems applications can share generic network functionalities defined by graph treversal o…
A Novel Multidimensional Scaling Technique for Mapping Word-Of-Mouth Discussions
2009
The techniques which utilize Multidimensional Scaling (MDS) as a fundamental statistical tool have been well developed since the late 1970’s. In this paper we show how anMDS scheme can be enhanced by incorporating into it a Stochastic Point Location (SPL) strategy (one which optimizes the former’s gradient descent learning phase) and a new Stress function. The enhanced method, referred to as MDS SPL, has been used in conjunction with a combination of the TF-IDF and Cosine Similarities on a very noisy Word-Of-Mouth (WoM) discussion set consisting of postings concerning mobile phones, yielding extremely satisfying results.
A Logical Explication of the Concepts of Incomplete and Uncertain Information
1994
Discovery of elementary knowledge and its constituents, i.e. information contained in objects of reality is realized through asking questions including certain aspects called attributes in this paper. We describe a fragment of a discovered reality as an information system (cf. Pawlak [1,3,4]), which consists of the universum U of all the objects of this reality we are concerned with, and of a set A of attributes understood as functions each of which assigns to every object of U 1) a value of given attribute belonging to A or 2) an interval of approximate values of this attribute, i.e. an established set of possible values of this attribute. From the point of view of the cognitive agent and …
Scatter Search and Path-Relinking: Fundamentals, Advances, and Applications
2010
Scatter search is an evolutionary metaheuristic that explores solution spaces by evolving a set of reference points, operating on a small set of solutions while making only limited use of randomization. We give a comprehensive description of the elements and methods that make up its template, including the most recent elements incorporated in successful applications in both global and combinatorial optimization. Path-relinking is an intensification strategy to explore trajectories connecting elite solutions obtained by heuristic methods such as scatter search, tabu search, and GRASP. We describe its mechanics, implementation issues, randomization, the use of pools of high-quality solutions …