554 research outputs found
Perfect Crystals for U_q(D_4^{(3)})
A perfect crystal of any level is constructed for the Kirillov-Reshetikhin
module of corresponding to the middle vertex of the Dynkin
diagram. The actions of Kashiwara operators are given explicitly. It is also
shown that this family of perfect crystals is coherent. A uniqueness problem
solved in this paper can be applied to other quantum affine algebras.Comment: 27 page
Automated reasoning on feature models
Software Product Line (SPL) Engineering has proved to be an effective method for software production. However, in the SPL community it is well recognized that variability in SPLs is increasing by the thousands. Hence, an automatic support is needed to deal with variability in SPL. Most of the current proposals for automatic reasoning on SPL are not devised to cope with extra– functional features. In this paper we introduce a proposal to model and reason on an SPL using constraint programming. We take into account functional and extra–functional features, improve current proposals and present a running, yet feasible implementation
Initial Commissioning of a Water-to-Water GHP System in KIER
GHP(Geothermal Heat Pump) system has been extensively disseminated due to the recent increasing demand of the new and renewable energy in Korea. However, the system reliability issues have been key barriers to ensure system performance as initially designed. This paper introduces a systematic method to verify its actually operating performance of a water to water GHP system. The main idea is to compare the actual performance with the manufacture data and then to reduce the gap between the actual and the manufacture data. The key result of this study is the development of a simplified GHP performance verification technique using the ISO standard based manufacture data. The manufacture performance data includes the information of EWT(entering water temperature), LWT(leaving water temperature), capacity, flow rate, power and COP. This technique has been verified to a w to w GHP system designed and installed at KIER site. The verification study showed that actual performance was lower than Manufacture data. And then the refrigerant was recharged and the compressor and the expansion valve were replaced. As a result, we can easily identify the GHP system problems and heating and cooling COP has been increased 25.26%,
18.24%
Weaving Variability into Domain Metamodels
International audienceDomain-Specific Modeling Languages (DSMLs) describe the concepts of a particular domain and their relationships, in a meta-model. From a given DSML, it is possible to describe a wide range of different models. These models often share a common base and vary on some parts. Current approaches tend to distinguish the variability language from the DSMLs themselves, implying greater learning curve for DSMLs stakeholders and a significant overhead in product line engineering of DSLs. We propose to consider variability concepts as an independent aspect to be woven into the DSML to introduce variability capabilities. In particular we detail how variability is woven and how to perform product line derivation. We validate our approach through the weaving of variability into two very different metamodels: Ecore and SmartAdapter, our aspect-oriented modelling weaver, thus adding exibility in the weaving process itself. These results emphasize how new abilities of the language can be provided by this means
Association between statins and the risk of suicide attempt, depression, anxiety, and seizure: A population-based, self-controlled case series study
Background:
Risk of suicide attempt, depression, anxiety and seizure and the association with statins is an ongoing debate. We aim to investigate the association between statins and the above neuropsychological outcomes, in specific pre- and post-exposure time windows./
Methods:
We identified patients aged 40–75 years old who were dispensed a statin between January 1, 2003 and December 31, 2012 from the Hong Kong Clinical Data Analysis & Reporting System (CDARS), an electronic medical records database. Patients with new onset of suicide attempt, depression, anxiety and seizure were derived from the original dataset separately, in a self-controlled case series study design. A non-parametric spline-based self-controlled case series model was built to measure continuous changes of risk./
Results:
We identified 396,614 statin users. The risk of each outcome was elevated prior to statin initiation with incidence rate ratios of 1.38 (95 % CI, 1.09–1.74) for suicide attempt, 1.29 (95 % CI, 1.15–1.45) for depression, 1.35 (95 % CI, 1.19–1.53) for anxiety, and 1.45 (95 % CI, 1.21–1.73) for seizure. The incidence rate ratios remained elevated after the initiation of statins during the first 90 and 91–365 days after statin prescription and decreased to the baseline level after 1 year of continuous prescription./
Limitations:
CDARS includes prescription data but not adherence data, which could lead to misclassification of exposure periods./
Conclusions:
Our study does not support a direct association between statin use and suicide attempt, depression, anxiety and seizure, whose risks could be explained by cardiovascular events, for which statins were prescribed
Magnetic and quantum entanglement properties of the distorted diamond chain model for azurite
We present the results of magnetic properties and entanglement of the
distorted diamond chain model for azurite using pure quantum exchange
interactions. The magnetic properties and concurrence as a measure of pairwise
thermal entanglement have been studied by means of variational mean-field like
treatment based on Gibbs-Bogoliubov inequality. Such a system can be considered
as an approximation of the natural material azurite, Cu3(CO3)2(OH)2. For values
of exchange parameters, which are taken from experimental results, we study the
thermodynamic properties, such as azurite specific heat and magnetic
susceptibility. We also have studied the thermal entanglement properties and
magnetization plateau of the distorted diamond chain model for azurite
Best-Effort Patching for Multicast True VoD Service
A multicast Video-on-Demand (VoD) system allows clients to share a server stream by batching their requests, and hence, improves channel utilization. However, it is very difficult to equip such a VoD system with full support for interactive VCR functions which are important to a growing number of Internet applications. In order to eliminate service (admission) latency, patching was proposed to enable an existing multicast session to dynamically add new clients, and requests can be served without delay if patching channels are available. A true VoD (TVoD) service should support not only zero-delay client admission but also continuous VCR-like interactivity. However, the conventional patching is only suitable for admission control. We propose a new patching scheme, called Best-Effort Patching (BEP), that offers a TVoD service in terms of both request admission and VCR interactivity. Moreover, by using a novel dynamic merging algorithm, BEP significantly improves the efficiency of TVoD interactivity, especially for popular videos. We also model and evaluate the efficiency of the dynamic merging algorithm. It is shown that BEP outperforms the conventional TVoD interaction protocols.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47328/1/11042_2005_Article_6851.pd
Optical symmetries and anisotropic transport in high-Tc superconductors
A simple symmetry analysis of in-plane and out-of-plane transport in a family
of high temperature superconductors is presented. It is shown that generalized
scaling relations exist between the low frequency electronic Raman response and
the low frequency in-plane and out-of-plane conductivities in both the normal
and superconducting states of the cuprates. Specifically, for both the normal
and superconducting state, the temperature dependence of the low frequency
Raman slope scales with the axis conductivity, while the
Raman slope scales with the in-plane conductivity. Comparison with experiments
in the normal state of Bi-2212 and Y-123 imply that the nodal transport is
largely doping independent and metallic, while transport near the BZ axes is
governed by a quantum critical point near doping holes per
CuO plaquette. Important differences for La-214 are discussed. It is also
shown that the axis conductivity rise for is a consequence of
partial conservation of in-plane momentum for out-of-plane transport.Comment: 16 pages, 8 Figures (3 pages added, new discussion on pseudogap and
charge ordering in La214
Performance of the CREAM calorimeter in accelerator beam test
The CREAM calorimeter, designed to measure the spectra of cosmic-ray nuclei from under 1 TeV to 1000 TeV, is a 20 radiation length (X0) deep sampling calorimeter. The calorimeter is comprised of 20 layers of tungsten interleaved with 20 layers of scintillating fiber ribbons, and is preceded by a pair of graphite interaction targets providing about 0.42 proton interaction lengths (\lambda int). The calorimeter was placed in one of CERN's SPS accelerator beams for calibration and testing. Beams of 150 GeV electrons were used for calibration, and a variety of electron, proton, and nuclear fragment beams were used to test the simulation model of the detector. In this paper we discuss the performance of the calorimeter in the electron beam and compare electron beam data with simulation results.The CREAM calorimeter, designed to measure the spectra of cosmic-ray nuclei from under 1 TeV to 1000 TeV, is a 20 radiation length (X0) deep sampling calorimeter. The calorimeter is comprised of 20 layers of tungsten interleaved with 20 layers of scintillating fiber ribbons, and is preceded by a pair of graphite interaction targets providing about 0.42 proton interaction lengths (\lambda int). The calorimeter was placed in one of CERN's SPS accelerator beams for calibration and testing. Beams of 150 GeV electrons were used for calibration, and a variety of electron, proton, and nuclear fragment beams were used to test the simulation model of the detector. In this paper we discuss the performance of the calorimeter in the electron beam and compare electron beam data with simulation results
Process Patterns for Component-Based Software Development
Abstract. Component-Based Development (CBD) has been broadly used in software development, as it enhances reusability and flexibility, and reduces the costs and risks involved in systems development. It has therefore spawned many widely-used approaches, such as Commercial Off-The-Shelf (COTS) and software product lines. On the other hand, in order to gain a competitive edge, organizations need to define custom processes tailored to fit their specific de-velopment requirements. This has led to the emergence of process patterns and Method Engineering approaches. We propose a set of process patterns commonly encountered in component-based development methodologies. Seven prominent component-based method-ologies have been selected and reviewed, and a set of high-level process patterns recurring in these methodologies have been identified. A generic process framework for component-based development has been proposed based on these process patterns. The process patterns and the generic framework can be used for developing or tailoring a process for producing component-based systems
- …