135 research outputs found
Agent Based Test and Repair of Distributed Systems
This article demonstrates how to use intelligent agents for testing and repairing a distributed system, whose elements may or may not have embedded BIST (Built-In Self-Test) and BISR (Built-In Self-Repair) facilities. Agents are software modules that perform monitoring, diagnosis and repair of the faults. They form together a society whose members communicate, set goals and solve tasks. An experimental solution is presented, and future developments of the proposed approach are explore
Coupled SDW and Superconducting Order in FFLO State of CeCoIn
The mechanism of incommensurate (IC) spin-density-wave (SDW) order observed
in the Flude-Ferrell-Larkin-Ovchinnikov (FFLO) phase of CeCoIn is discussed
on the basis of new mode-coupling scheme among IC-SDW order, two
superconducting orders of FFLO with B () symmetry
and -pairing of odd-parity. Unlike the mode-coupling schemes proposed by
Kenzelmann et al, Sciencexpress, 21 August (2008), that proposed in the present
Letter can offer a simple explanation for why the IC-SDW order is observed only
in FFLO phase and the IC wave vector is rather robust against the magnetic
field.Comment: 3pages, 1 figure, accepted for publication in J. Phys. Soc. Jpn.,
Vol.77 (2008), No.1
Agent Based Test and Repair of Distributed Systems
This article demonstrates how to use intelligent agents for testing and repairing a distributed system, whose elements may or may not have embedded BIST (Built-In Self-Test) and BISR (Built-In Self-Repair) facilities.
Agents are software modules that perform monitoring, diagnosis and repair of the faults. They form together a society whose members communicate, set goals and solve tasks.
An experimental solution is presented, and future developments of the proposed approach are explored
Towards microagent based DBIST/DBISR
We present some ideas and experiments on using microagents for testing and repairing a distributed system, whose elements may or may not have embedded BIST (built in self test) and BISR (built in self repair) facilities. The microagents are software modules that perform monitoring, diagnosis and repair of the faults. They form together a society whose members communicate, set goals and solve tasks. The platforms taken into consideration for mobile tester microagents include Java Micro Edition, BREW, Symbian, PalmOS, as well as more general small scale platforms. Experimental tester agents in Java 2 Micro Edition and PalmOS are also presented, a solution that ensures portability, flexibility, but also a relatively small memory footprint
A cloud-based Cyber-Physical System for environmental monitoring
Cyber-Physical Systems (CPSs) represent a new generation of digital systems, where cyber entities and physical devices cooperate towards a set of common goals. The research presented in this paper aims to contribute to the development of CPSs by proposing an open architecture applicable in environmental monitoring, consisting of three layers. The paper provides a detailed description of each one of the CPS's main components. The bottom layer, composed of wireless sensor nodes, allows the acquisition of data and their transfer to the upper layers. The top and middle layers, composed of a measurements database, a knowledge base, a multi-agent society and web services, assure the proper operation of the CPS based on decision rules and complex data analyses. The proposed architecture provides a high degree of flexibility and scalability
Argon metastable dynamics in a filamentary jet micro-discharge at atmospheric pressure
Space and time resolved concentrations of Ar () metastable atoms at
the exit of an atmospheric pressure radio-frequency micro-plasma jet were
measured using tunable diode laser absorption spectroscopy. The discharge
features a coaxial geometry with a hollow capillary as an inner electrode and a
ceramic tube with metal ring as outer electrode. Absorption profiles of
metastable atoms as well as optical emission measurements reveal the dynamics
and the filamentary structure of the discharge. The average spatial
distribution of Ar metastables is characterized with and without a target in
front of the jet, showing that the target potential and therewith the electric
field distribution substantially changes the filaments' expansion. Together
with the detailed analysis of the ignition phase and the discharge's behavior
under pulsed operation, the results give an insight into the excitation and
de-excitation mechanisms
Adenomatous polyposis coli-mediated control of β-catenin is essential for both chondrogenic and osteogenic differentiation of skeletal precursors
Background: During skeletogenesis, protein levels of β-catenin in the canonical Wnt signaling pathway determine lineage commitment of skeletal precursor cells to osteoblasts and chondrocytes. Adenomatous polyposis coli (Apc) is a key controller of β-catenin turnover by down-regulating intracellular levels of β-catenin. Results: To investigate whether Apc is involved in lineage commitment of skeletal precursor cells, we generated conditional knockout mice lacking functional Apc in Col2a1-expressing cells. In contrast to other models in which an oncogenic variant of β-catenin was used, our approach resulted in the accumulation of wild type β-catenin protein due to functional loss of Apc. Conditional homozygous Apc mutant mice died perinatally showing greatly impaired skeletogenesis. All endochondral bones were misshaped and lacked structural integrity. Lack of functional Apc resulted in a pleiotropic skeletal cell phenotype. The majority of the precursor cells lacking Apc failed to differentiate into chondrocytes or osteoblasts. However, skeletal precursor cells in the proximal ribs were able to escape the noxious effect of functional loss of Apc resulting in formation of highly active osteoblasts. Inactivation of Apc in chondrocytes was associated with dedifferentiation of these cells. Conclusion: Our data indicate that a tight Apc-mediated control of β-catenin levels is essential for differentiation of skeletal precursors as well as for the maintenance of a chondrocytic phenotype in a spatio-temporal regulated manner
Bose glass and Mott glass of quasiparticles in a doped quantum magnet
The low-temperature states of bosonic fluids exhibit fundamental quantum
effects at the macroscopic scale: the best-known examples are Bose-Einstein
condensation (BEC) and superfluidity, which have been tested experimentally in
a variety of different systems. When bosons are interacting, disorder can
destroy condensation leading to a so-called Bose glass. This phase has been
very elusive to experiments due to the absence of any broken symmetry and of a
finite energy gap in the spectrum. Here we report the observation of a Bose
glass of field-induced magnetic quasiparticles in a doped quantum magnet
(Br-doped dichloro-tetrakis-thiourea-Nickel, DTN). The physics of DTN in a
magnetic field is equivalent to that of a lattice gas of bosons in the
grand-canonical ensemble; Br-doping introduces disorder in the hoppings and
interaction strengths, leading to localization of the bosons into a Bose glass
down to zero field, where it acquires the nature of an incompressible Mott
glass. The transition from the Bose glass (corresponding to a gapless spin
liquid) to the BEC (corresponding to a magnetically ordered phase) is marked by
a novel, universal exponent governing the scaling on the critical temperature
with the applied field, in excellent agreement with theoretical predictions.
Our study represents the first, quantitative account of the universal features
of disordered bosons in the grand-canonical ensemble.Comment: 13+6 pages, 5+6 figures; v2: Fig. 5 update
Superconductivity in LaFeAsPO: effect of chemical pressures and bond covalency
We report the realization of superconductivity by an isovalent doping with
phosphorus in LaFeAsO. X-ray diffraction shows that, with the partial
substitution of P for As, the FeAs layers are squeezed while the
LaO layers are stretched along the c-axis. Electrical resistance and
magnetization measurements show emergence of bulk superconductivity at 10
K for the optimally-doped LaFeAsPO (). The upper
critical fields at zero temperature is estimated to be 27 T, much higher than
that of the LaFePO superconductor. The occurrence of superconductivity is
discussed in terms of chemical pressures and bond covalency.Comment: 5 pages, 6 figures, more data presente
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