pinecone/core-2020-05-10-deduplication huggingface dataset:
Simple exclusion process : from randomness to determinism

In this work I introduce a classical example of an Interacting Particle System: the Simple Exclusion Process. I present the notion of
hydrodynamic limit, which is a Law of Large Numbers for the empirical measure and an heuristic argument to derive from the microscopic dynamics
between particles a partial differential equation describing the evolution of the density profile. For the Simple Exclusion Process, in the
Symmetric case ($p=1/2$) we will get to the heat equation while in the Asymmetric case ($p\neq{1/2}$) to the inviscid Burgers equation. Finally,
I introduce the Central Limit Theorem for the empirical measure and the limiting process turns out to be a solution of a stochastic partial
differential equation
Characterizing Tractability by Tissue-Like P System

In the framework of recognizer cell–like membrane systems\ud
it is well known that the construction of exponential number of objects\ud
in polynomial time is not enough to efficiently solve NP–complete problems.\ud
Nonetheless, it may be sufficient to create an exponential number\ud
of membranes in polynomial time.\ud
In this paper, we study the computational efficiency of recognizer tissue\ud
P systems with communication (symport/antiport) rules and division\ud
rules. Some results have been already obtained in this direction: (a) using\ud
communication rules and making no use of division rules, only tractable\ud
problems can be efficiently solved; (b) using communication rules with\ud
length three and division rules, NP–complete problems can be efficiently\ud
solved. In this paper, we show that the length of communication rules\ud
plays a relevant role from the efficiency point of view for this kind of P\ud
systems.Postprint (published version
Non-equilibrium dynamics of quantum systems: order parameter evolution,
  defect generation, and qubit transfer

In this review, we study some aspects of the non-equilibrium dynamics of
quantum systems. In particular, we consider the effect of varying a parameter
in the Hamiltonian of a quantum system which takes it across a quantum critical
point or line. We study both sudden and slow quenches in a variety of systems
including one-dimensional ultracold atoms in an optical lattice, an infinite
range ferromagnetic Ising model, and some exactly solvable spin models in one
and two dimensions (such as the Kitaev model). We show that quenching leads to
the formation of defects whose density has a power-law dependence on the
quenching rate; the power depends on the dimensionalities of the system and of
the critical surface and on some of the exponents associated with the critical
point which is being crossed. We also study the effect of non-linear quenching;
the power law of the defects then depends on the degree of non-linearity.
Finally, we study some spin-1/2 models to discuss how a qubit can be
transferred across a system.Comment: 36 pages, 14 figures; an updated version will be published in
  "Quantum Quenching, Annealing and Computation", Eds. A. Das, A. Chandra and
  B. K. Chakrabarti, Lect. Notes in Phys., Springer, Heidelberg (2009, to be
  published
Adiabatic perturbation theory: from Landau-Zener problem to quenching
  through a quantum critical point

We discuss the application of the adiabatic perturbation theory to analyze
the dynamics in various systems in the limit of slow parametric changes of the
Hamiltonian. We first consider a two-level system and give an elementary
derivation of the asymptotics of the transition probability when the tuning
parameter slowly changes in the finite range. Then we apply this perturbation
theory to many-particle systems with low energy spectrum characterized by
quasiparticle excitations. Within this approach we derive the scaling of
various quantities such as the density of generated defects, entropy and
energy. We discuss the applications of this approach to a specific situation
where the system crosses a quantum critical point. We also show the connection
between adiabatic and sudden quenches near a quantum phase transitions and
discuss the effects of quasiparticle statistics on slow and sudden quenches at
finite temperatures.Comment: 20 pages, 3 figures, contribution to "Quantum Quenching, Annealing
  and Computation", Eds. A. Das, A. Chandra and B. K. Chakrabarti, Lect. Notes
  in Phys., Springer, Heidelberg (2009, to be published), reference correcte
Glottal source estimation using an automatic chirp decomposition

International Conference on Nonlinear Speech Processing, NOLISP 2009; Vic; Spain; 25 June 2009 through 27 June 2009In a previous work, we showed that the glottal source can be estimated from speech signals by computing the Zeros of the Z-Transform (ZZT). Decomposition was achieved by separating the roots inside (causal contribution) and outside (anticausal contribution) the unit circle. In order to guarantee a correct deconvolution, time alignment on the Glottal Closure Instants (GCIs) was shown to be essential. This paper extends the formalism of ZZT by evaluating the Z-transform on a contour possibly different from the unit circle. A method is proposed for determining automatically this contour by inspecting the root distribution. The derived Zeros of the Chirp Z-Transform (ZCZT)-based technique turns out to be much more robust to GCI location errors. © 2010 Springer-Verlag
Concurrent objects à la carte

Services are autonomous, self-describing, technology-neutral software units that can be described, published, discovered, and composed into software applications at run-time. Designing software services and composing services in order to form applications or composite services requires abstractions beyond those found in typical object- oriented programming languages. In this paper, we explore a number of the abstractions used in service-oriented computing and related internet- and web-based programming models in the context of Creol, an executable concurrent object-oriented modelling language with active objects and futures; i.e., features capable of expressing and dealing with asynchronous actions. By adding various abstractions to the modelling language, we demonstrate how a concurrent object language may nat- urally address many of the requirements of service-oriented computing. The study of language extensions in the restricted setting of a small, high-level modelling language, such as Creol, suggests a cheap way of developing new abstractions for emerging application domains. In this paper, we explore abstractions in the context of service-oriented computing, particularly with regard to dynamic aspects such as service discovery and structuring mechanisms such as groups.status: publishe
Reducing Memory Latency by Improving Resource Utilization

<p>Integrated circuits have been in constant progression since the first prototype in 1958, with the semiconductor industry maintaining a constant rate of miniaturisation of transistors and wires. Up until about the year 2002, processor performance increased by about 55% per year. Since then, limitations on power, ILP and memory latency have slowed the increase in uniprocessor performance to about 20% per year. Although the capacity of DRAM increases by about 40% per year, the latency only decreases by about 6 { 7% per year. This performance gap between the processor and DRAM leads to a problem known as the memory wall.</p><p>This thesis aims to improve system memory latency by leveraging available resources with excess capacity. This has been achieved through multiple techniques, but mainly by using excess bandwidth and improving scheduling policies.</p><p>The first approach presented, destructive read DRAM, changes the underlying assumptions about the contents of a DRAM cell being unchanged after a read. The latency of a read is reduced, but the rest of the memory system requires changes to conserve data.</p><p>Prefetching predicts what data is needed in the future and fetches that data into the cache before it is referenced. This dissertation presents a technique for generating highly accurate prefetches with good timeliness called <em>Delta Correlating Prediction Tables (DCPT). </em>DCPT uses a table indexed by the load's address to store the delta history of individual loads. Delta correlation is then used to predict future misses. <em>Delta Correlating Prediction Tables with Partial Matching (DCPT-P)</em> extends DCPT by introducing<em> L1 hoisting</em> which moves data from the L2 to the L1 to further increase performance. In addition, DCPT-P leverages <em>partial matching </em>which reduces the spatial resolution of deltas to expose more patterns.</p><p>The interaction between the memory controller and the prefetcher is especially important, because of the complex 3D structure of modern DRAM. Utilizing open pages can increase the performance of the system significantly. Memory controllers can increase bandwidth utilization and reduce latency at the same time by scheduling prefetches such that the number of page hits are maximized. The interaction between the program, prefetcher and the memory controller is explored.</p><p>This thesis examines the impact of having a shared memory system in a CMP. When resources are shared, one core might interfere with another core's execution by delaying memory requests or displacing useful data in the cache. This effect is quantified and which components are most prone to interference between cores identified. Finally, we present a framework for measuring interference at runtime.</p>PhD i informasjons- og kommunikasjonsteknologiPhD in Information and Communications Technolog
Buffer sizing for self-timed stream programs on heterogeneous distributed memory multiprocessors

Stream programming is a promising way to expose concurrency to the compiler. A stream program is built from kernels that communicate only via point-to-point streams. The stream compiler statically allocates these kernels to processors, applying blocking, fission and fusion transformations. The compiler determines the sizes of the communication buffers, which affects performance since local memories can be small.\ud
In this paper, we propose a feedback-directed algorithm that determines the size of each communication buffer, based on i) the stream program that has been mapped onto processors, ii) feedback from an earlier execution, and iii) the memory constraints. The algorithm exposes a trade-off between throughput and latency. It is general, in that it applies to stream programs with unstructured stream graphs, and it supports variable execution times and communication rates.\ud
We show results for the StreamIt benchmarks and random graphs. For the StreamIt benchmarks, throughput is optimal after the first iteration. For random graphs with stochastic computation times, throughput is within 3% of optimal after four iterations. Compared with the previous general algorithm, by Basten and Hoogerbrugge, our algorithm has significantly better performance and latency.Postprint (published version
All Roads Lead to Rome: Data Highways for Dense Wireless Sensor Networks

The design of efficient routing algorithms is an important issue in dense ad hoc wireless networks. Previous work has shown that benefits can be achieved through the creation of a set of data highways that carry packets across the network, from source(s) to sink(s). Current approaches to the design of these highways however require apriori knowledge of the global network topology, with consequent communications burden and scalability issues, particularly with regard to reconfiguration after node failures. In this paper we describe an approach to generating these data highways through a distributed reaction-diffusion model that uses localised convolution with activation-inhibition filters. The result is the distributed emergence of data highways that can be tuned to provide appropriate highway separation and connection to data sinks. We present the underlying models and the algorithms for generating the highways, as well as preliminary simulation results
Energy-aware dynamic route management for THAWS

In this research we focus on the Tyndall 25mm and 10mm nodes energy-aware topology management to extend sensor network lifespan and optimise node power consumption. The two tiered Tyndall Heterogeneous Automated Wireless Sensors (THAWS) tool is used to quickly create and configure application-specific sensor networks. To this end, we propose to implement a distributed route discovery algorithm and a practical energy-aware reaction model on the 25mm nodes. Triggered by the energy-warning events, the miniaturised Tyndall 10mm data collector nodes adaptively and periodically change their association to 25mm base station nodes, while 25mm nodes also change the inter-connections between themselves, which results in reconfiguration of the 25mm nodes tier topology. The distributed routing protocol uses combined weight functions to balance the sensor network traffic. A system level simulation is used to quantify the benefit of the route management framework when compared to other state of the art approaches in terms of the system power-saving
Trade-off analysis of a MAC protocol for wireless e-Emergency systems

Wireless sensor networks are envisioned to be deployed in healthcare.
Since emergency and intensive care applications need to assure reliable
and timely data delivery, they have increased demands for quality of service,
including at the MAC layer. Amongst MAC protocols available for WSNs, the
Low Power Real Time (LPRT) presents suitable characteristics to be deployed
in emergency platforms due to its rational bandwidth allocation, low energy
consumption, and bounded latency. Yet, this protocol may present a significant
packet loss ratio in a wireless channel with bit error ratio. In order to define a
MAC protocol more robust to bit error conditions and able to fulfill the required
quality of service, solutions based on short size beacons and multiple retransmissions
are proposed and tested. The results showed that such strategies led to
meaningful improvements regarding packet loss ratio, without compromising
significantly the energy consumption.Fundação para a Ciência e a Tecnologia (FCT
Evaluation of the impact of the topology and Hidden Nodes in the performance of a ZigBee Network

Low power and small footprint IEEE 802.15.4/ZigBee based devices
are a promising alternative to 802.11a/b/g and proprietary protocols for
non-critical patient monitoring under important scenarios such as post-op and
emergency rooms. However, their use in a healthcare facility to monitor several
mobile patients poses several difficulties, mainly because these protocols were
primarily designed to operate in low traffic load scenarios. This work presents
simulation results used to evaluate the performance of an IEEE 802.15.4/ Zig-
Bee based wireless sensors network (WSN) in a vital signs monitoring scenario,
for both star and tree based network topologies. The scalability problem in nonbeacon
enabled networks is addressed to quantify the degradation in quality of
service (QoS) markers when the number of sensor nodes increase. Additionally,
the impact of hidden nodes is assessed for the star topology. Results indicate
that, to achieve a delivery ratio (DR) higher than 99%, the number of electrocardiogram
(ECG) nodes in a star network must not exceed 35. However, considering
a tree topology, the maximum number of nodes must be reduced to 18
to maintain the same DR. The network performance is severely impacted by
hidden nodes. For instance, in the absence of hidden nodes, a star network
consisting of 32 ECG nodes presents a DR higher than 99%; however, if the
percentage of hidden nodes is increased to 5%, it drops to 94%. If the same percentage
of hidden nodes is maintained, it is necessary to reduce the number of
nodes to 13 to reestablish a 99% DR.Fundação para a Ciência e a Tecnologia (FCT)Grupo AMI - Assistência Médica Integral (Casa de Saúde Guimarães, SA
A forward and backward secure key management in wireless sensor networks for PCS/SCADA

Process Control Systems (PCSs) or Supervisory Control and\ud
Data Acquisition (SCADA) systems have recently been added to the already wide collection of wireless sensor networks applications. The PCS/SCADA environment is somewhat more amenable to the use of heavy cryptographic mechanisms such as public key cryptography than other sensor application environments. The sensor nodes in the environment, however, are still open to devastating attacks such as node capture, which makes designing a secure key management challenging. In this paper, a key management scheme is proposed to defeat node capture attack by offering both forward and backward secrecies. Our scheme overcomes the pitfalls which Nilsson et al.'s scheme suffers from, and is not more expensive than their scheme
3 case studies: a hybrid educational strategy for ART/SCI collaborations

In this paper we report on a transdisciplinary university course designed to bring together fine art/visual communication design and computer science students for the creation and implementation of collaborative visual/audio projects that draw upon the specialized knowledge of both these disciplines. While an overview of the syllabus and the teaching methodologies is undertaken in the introduction, the focus of the paper concentrates upon an in-depth discussion and analysis of 3 specific projects that were developed by 3 distinct teams of students comprised of one artist/designer and one engineer each
How Form Errors Impact on 2D Precision Assembly with Clearance?

International audienceMost models of assembling simulations consider that form errors are negligible, but how can this assumption be assessed? When clearances are high, form deviations can be neglected, but on the case of very precise mechanisms with small clearances, this assumption can lead to non-accurate models. This paper is the continuation of our previous works presented at IPAS 2008 dealing with the assembly of two parts regarding their form deviation. The proposed method considers the positioning of the pair of surface with a given external force to identify contact points. The parts relative positioning is expressed by a small displacement torsor that can be transferred to any referee and compared to the functional requirement. The objective of this paper is to identify the clearance domain of a mechanical linkage regarding the form deviation of parts. Several parameters are identified as influent such as the clearance value, the straightness of the form deviation and the localization of the ideal least squared associated shape
Development of a computer simulation tool for\ud
application in adolescent spinal deformity surgery

Scoliosis is a three-dimensional spinal deformity which requires surgical correction in progressive cases. In order to optimize correction and avoid complications following scoliosis surgery, patient-specific finite element models (FEM) are being developed and validated by our group. In this paper, the modeling methodology is described and two clinically relevant load cases are simulated for a single patient. Firstly, a pre-operative patient flexibility assessment, the fulcrum bending radiograph, is simulated to assess the model's ability to represent spine flexibility. Secondly, intra-operative forces during single rod anterior correction are simulated. Clinically, the patient had an initial Cobb angle of 44 degrees, which reduced to 26 degrees during fulcrum bending. Surgically, the coronal deformity corrected to 14 degrees. The simulated initial Cobb angle was 40 degrees, which reduced to 23 degrees following the fulcrum bending load case. The simulated surgical procedure\ud
corrected the coronal deformity to 14 degrees. The computed results for the patient-specific FEM are within the accepted clinical Cobb measuring error of 5 degrees, suggested that this modeling methodology is capable of capturing the biomechanical behaviour of a scoliotic human spine during anterior corrective surgery
A coordination model for interactive components

Although presented with a variety of ‘flavours’, the notion of an interactor, as an abstract characterisation of an interactive com- ponent, is well-known in the area of formal modelling techniques for interactive systems. This paper replaces traditional, hierarchical, ‘tree-like’ composition of interactors in the specification of complex interactive sys- tems, by their exogenous coordination through general-purpose software connectors which assure the flow of data and the meet of synchronisation constraints. The paper’s technical contribution is twofold. First a modal logic is defined to express behavioural properties of both interactors and connectors. The logic is new in the sense that its modalities are indexed by fragments of sets of actions to cater for action co-occurrence. Then, this logic is used in the specification of both interactors and coordination layers which orchestrate their interconnection
Survey of media forms and information flow models in microsystems companies

The paper presents the findings of a survey of 40 microsystems companies that
was carried out to determine the use and the purpose of use of media forms and
information flow models within these companies. These companies as
"product-service systems' delivered integrated products and services to
realise customer solutions. Data collection was carried out by means of an
online survey over 3 months. The survey revealed that 42.5% of respondents made
use of data flow diagrams and 10% made use of design structure matrices. The
survey also suggests that a majority of companies (75%) made use of textual and
diagrammatic media forms for communication, analysis, documentation and
representation during design and development processes. The paper also discusses
the implications of the survey findings to product-service systems
Learning with whom to communicate using relational reinforcement learning

Relational reinforcement learning is a promising direction within reinforcement
learning research. It upgrades reinforcement learning techniques by using
relational representations for states, actions, and learned value-functions or policies to allow natural representations and abstractions of complex tasks. Multi-agent systems
are characterized by their relational structure and present a good example of
a complex task. In this paper, we show how relational reinforcement learning could
be a useful tool for learning in multi-agent systems.We study this approach in more
detail on one important aspect of multi-agent systems, i.e., on learning a communication
policy for cooperative systems (e.g., resource distribution). Communication
between agents in realistic multi-agent systems can be assumed costly, limited and
unreliable. We perform a number of experiments that highlight the conditions in
which relational representations can be beneficial when taking the constraints mentioned
above into account.status: publishe