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961.
Marc Karle Johannes W?hrle Junichi Miwa Nils Paust G��nter Roth Roland Zengerle Felix von Stetten 《Microfluidics and nanofluidics》2011,10(4):935-939
We demonstrate controlled transport of superparamagnetic beads in the opposite direction of a laminar flow. A permanent magnet
assembles 200 nm magnetic particles into about 200 μm long bead chains that are aligned in parallel to the magnetic field
lines. Due to a magnetic field gradient, the bead chains are attracted towards the wall of a microfluidic channel. A rotation
of the permanent magnet results in a rotation of the bead chains in the opposite direction to the magnet. Due to friction
on the surface, the bead chains roll along the channel wall, even in counter-flow direction, up to at a maximum counter-flow
velocity of 8 mm s−1. Based on this approach, magnetic beads can be accurately manoeuvred within microfluidic channels. This counter-flow motion
can be efficiently be used in Lab-on-a-Chip systems, e.g. for implementing washing steps in DNA purification. 相似文献
962.
In this paper, we study singularly perturbed impulsive stochastic delay differential systems (SPISDDSs). By establishing an
L-operator delay differential inequality and using the stochastic analysis technique, we obtain some sufficient conditions
ensuring the exponential p-stability of any solution of SPISDDSs for sufficiently small ɛ > 0. The results extend and improve the earlier publications. An example is also discussed to illustrate the efficiency of
the obtained results. 相似文献
963.
Jin-Xing?LinEmail author Xian-Lin?Zhao Shu-Min?Fei 《International Journal of Control, Automation and Systems》2011,9(2):218-227
This paper considers the problem of exponential stability for continuous-time singular systems with interval time-varying
delay. By defining a novel Lyapunov-Krasovskii function and giving a tighter upper bound of its derivative, a new delay-range-dependent
exponential admissibility criterion, which not only guarantees the regularity, absence of impulses and exponential stability
of the system but also gives the estimates of decay rate and decay coefficient, is established in terms of linear matrix inequality
(LMI). The resulting criterion has advantages over the result previously reported by Haidar et al. [17] in that it involves fewer matrix variables but has less conservatism, which is established theoretically. Examples are
provided to demonstrate the advantage of the proposed criterion. 相似文献
964.
We present a non-intrusive molecular dye based method, i.e., laser-induced fluorescence photobleaching anemometer (LIFPA),
to significantly increase temporal resolution (TR) for velocity measurement of fast transient electrokinetic flows. To our
knowledge, the TR has been for the first time achieved to 5–10 μs, about 100 times better than that published from state-of-the-art
micro particle image velocimetry (μPIV), which is currently the most widely used velocimetry in the microfluidics community.
The new method provides us with new opportunities to study experimentally the fundamental phenomena of unsteady electrokinetics
(EK) and to validate relevant theoretical models. One application of the new method is demonstrated by measuring the rise
time of DC electroosmotic flows (EOFs) in a microcapillary of 10 μm in diameter. 相似文献
965.
Thomas?Lavergne Tanguy?Urvoy Fran?ois?YvonEmail author 《Language Resources and Evaluation》2011,45(1):25-43
Fake content is flourishing on the Internet, ranging from basic random word salads to web scraping. Most of this fake content
is generated for the purpose of nourishing fake web sites aimed at biasing search engine indexes: at the scale of a search
engine, using automatically generated texts render such sites harder to detect than using copies of existing pages. In this
paper, we present three methods aimed at distinguishing natural texts from artificially generated ones: the first method uses
basic lexicometric features, the second one uses standard language models and the third one is based on a relative entropy
measure which captures short range dependencies between words. Our experiments show that lexicometric features and language
models are efficient to detect most generated texts, but fail to detect texts that are generated with high order Markov models.
By comparison our relative entropy scoring algorithm, especially when trained on a large corpus, allows us to detect these
“hard” text generators with a high degree of accuracy. 相似文献
966.
Georg Birkenheuer Andr�� Brinkmann Mikael H?gqvist Alexander Papaspyrou Bernhard Schott Dietmar Sommerfeld Wolfgang Ziegler 《Journal of Grid Computing》2011,9(3):355-377
Infrastructure federation is becoming an increasingly important issue for modern Distributed Computing Infrastructures (DCIs):
Dynamic elasticity of quasi-static Grid environments, incorporation of special-purpose resources into commoditized Cloud infrastructures,
cross-community collaboration for increasingly diverging areas of modern e-Science, and Cloud Bursting pose major challenges
on the technical level for many resource and middleware providers. Especially with respect to increasing costs of operating
data centers, the intelligent yet automated and secure sharing of resources is a key factor for success. With the D-Grid Scheduler
Interoperability (DGSI) project within the German D-Grid Initiative, we provide a strategic technology for the automatically
negotiated, SLA-secured, dynamically provisioned federation of resources and services for Grid-and Cloud-type infrastructures.
This goal is achieved by complementing current DCI schedulers with the ability to federate infrastructure for the temporary
leasing of resources and rechanneling of workloads. In this work, we describe the overall architecture and SLA-secured negotiation
protocols within DGSI and depict an advanced mechanism for resource delegation through means of dynamically provisioned, virtualized
middleware. Through this methodology, we provide the technological foundation for intelligent capacity planning and workload
management in a cross-infrastructure fashion. 相似文献
967.
Boles?aw Kacewicz 《Quantum Information Processing》2011,10(3):279-296
We deal with quantum and randomized algorithms for approximating a class of linear continuous functionals. The functionals
are defined on a H?lder space of functions f of d variables with r continuous partial derivatives, the rth derivative being a H?lder function with exponent ρ. For a certain class of such linear problems (which includes the integration problem), we define algorithms based on partitioning
the domain of f into a large number of small subdomains, and making use of the well-known quantum or randomized algorithms for summation
of real numbers. For N information evaluations (quantum queries in the quantum setting), we show upper bounds on the error of order N
−(γ+1) in the quantum setting, and N
−(γ+1/2) in the randomized setting, where γ = (r + ρ)/d is the regularity parameter. Hence, we obtain for a wider class of linear problems the same upper bounds as those known for
the integration problem. We give examples of functionals satisfying the assumptions, among which we discuss functionals defined
on the solution of Fredholm integral equations of the second kind, with complete information about the kernel. We also provide
lower bounds, showing in some cases sharpness of the obtained results, and compare the power of quantum, randomized and deterministic
algorithms for the exemplary problems. 相似文献
968.
Haiping?MaEmail author Xieyong?Ruan Zhangxin?Pan 《International Journal of Control, Automation and Systems》2011,9(1):125-131
In order to have a good performance for maneuvering target tracking, a genetic interacting multiple model (GIMM) algorithm
based on the H
∞ filter is proposed in this paper. It introduces the H
∞ filter as model-conditional filter, which keeps its robustness by constantly adjusting parameters, to improve the performance
and the precision. Meanwhile, it optimizes model probabilities using the genetic algorithm (GA), chooses sub-models which
are close to true models from a set of models, adjusts the number of models and parameters in real-time, reduces excessive
competition, and improves the performance of the algorithm. The simulation results indicate that, the algorithm has higher
tracking accuracy and stronger robustness than the standard IMM algorithm. 相似文献
969.
Human activity recognition is a challenging problem for context-aware systems and applications. Research in this field has
mainly adopted techniques based on supervised learning algorithms, but these systems suffer from scalability issues with respect
to the number of considered activities and contextual data. In this paper, we propose a solution based on the use of ontologies
and ontological reasoning combined with statistical inferencing. Structured symbolic knowledge about the environment surrounding
the user allows the recognition system to infer which activities among the candidates identified by statistical methods are
more likely to be the actual activity that the user is performing. Ontological reasoning is also integrated with statistical
methods to recognize complex activities that cannot be derived by statistical methods alone. The effectiveness of the proposed
technique is supported by experiments with a complete implementation of the system using commercially available sensors and
an Android-based handheld device as the host for the main activity recognition module. 相似文献
970.
Stephen Gilmore L��szl�� G?nczy Nora Koch Philip Mayer Mirco Tribastone D��niel Varr�� 《Software and Systems Modeling》2011,10(3):287-311
Systems based on the service-oriented architecture (SOA) principles have become an important cornerstone of the development
of enterprise-scale software applications. They are characterized by separating functions into distinct software units, called
services, which can be published, requested and dynamically combined in the production of business applications. Service-oriented
systems (SOSs) promise high flexibility, improved maintainability, and simple re-use of functionality. Achieving these properties
requires an understanding not only of the individual artifacts of the system but also their integration. In this context,
non-functional aspects play an important role and should be analyzed and modeled as early as possible in the development cycle.
In this paper, we discuss modeling of non-functional aspects of service-oriented systems, and the use of these models for
analysis and deployment. Our contribution in this paper is threefold. First, we show how services and service compositions
may be modeled in UML by using a profile for SOA (UML4SOA) and how non-functional properties of service-oriented systems can
be represented using the non-functional extension of UML4SOA (UML4SOA-NFP) and the MARTE profile. This enables modeling of
performance, security and reliable messaging. Second, we discuss formal analysis of models which respect this design, in particular
we consider performance estimates and reliability analysis using the stochastically timed process algebra PEPA as the underlying
analytical engine. Last but not least, our models are the source for the application of deployment mechanisms which comprise
model-to-model and model-to-text transformations implemented in the framework VIATRA. All techniques presented in this work
are illustrated by a running example from an eUniversity case study. 相似文献