Search results for "Distributed"
showing 10 items of 1260 documents
Priority Based Coordinated Electric Vehicle Charging System for Heterogeneous Traffic
2020
Despite the environmental and health merits associated with Electric vehicles (EVs), a massive deployment of EVs tends to create new technical and economic challenges for power systems. This is being addressed with different coordinated charging schemes where the charging coordination is distributed across multiple EVs and/or aggregators based on different objectives. This work analyzes an algorithm which maximize the operational profit of a charging station with a high charging station utilization while adhering all the constraints enforced by the utility grid. And it is analyzed the performance of the coordinated charging scheme which facilitates heterogeneous EV users whose arrival is un…
Life Cycle Assessment Performance Comparison of Small Solar Thermal Cooling Systems with Conventional Plants Assisted with Photovoltaics
2012
Abstract Life Cycle Assessment (LCA) allows for the consideration of energy consumption and environmental impacts associated with all the stages of a product's life, from the cradle to the grave . Starting from the results obtained in the IEA SHC Task 38 framework for the LCA of small solar assisted heat driven chillers, the application of such methodology has been extended to systems with a conventional compression chiller assisted by a photovoltaic plant. This study aims to provide a more comprehensive investigation through a comparison of these two families of solar assisted cooling systems (with solar thermal or PV), which is an important topic for studies concerning the research of eff…
Demonstration of an efficient pumping scheme for a 7.36-nm Ni-like samarium soft x-ray laser
2010
The demonstration of a 7.36 nm Ni-like Sm soft x-ray laser pumped by 36 J of a Nd:glass chirped pulse amplification laser is presented. Double-pulse single-beam non-normal incidence pumping was applied for the efficient soft x-ray laser generation. Here the applied technique included a new single optic focusing geometry for large beam diameters, a single-pass grating compressor traveling-wave tuning capability and an optimized high energy laser double-pulse. This scheme has the potential for even shorter wavelength soft x-ray laser pumping.
Identifying individual differences using log-file analysis: Distributed learning as mediator between conscientiousness and exam grades
2018
Abstract Online learning poses major challenges on students' self-regulated learning. This study investigated the role of learning strategies and individual differences in cognitive abilities, high school GPA and conscientiousness for successful online learning. We used longitudinal log-file data to examine learning strategies of a large cohort (N = 424) of university students taking an online class. Distributed learning, the use of self-tests and a better high school GPA was associated with better exam grades. The positive effect of conscientiousness on exam grades was mediated by distributed learning. Conscientious students distributed their studying over the course of the semester, which…
Comparative analysis of architectures for monitoring cloud computing infrastructures
2015
The lack of control over the cloud resources is one of the main disadvantages associated to cloud computing. The design of efficient architectures for monitoring such resources can help to overcome this problem. This contribution describes a complete set of architectures for monitoring cloud computing infrastructures, and provides a taxonomy of them. The architectures are described in detail, compared among them, and analysed in terms of performance, scalability, usage of resources, and security capabilities. The architectures have been implemented in real world settings and empirically validated against a real cloud computing infrastructure based on OpenStack. More than 1000 virtual machin…
Distributing Storage in Cloud Environments
2013
Cloud computing has a major impact on today's IT strategies. Outsourcing applications from IT departments to the cloud relieves users from building big infrastructures as well as from building the corresponding expertise, and allows them to focus on their main competences and businesses. One of the main hurdles of cloud computing is that not only the application, but also the data has to be moved to the cloud. Networking speed severely limits the amount of data that can travel between the cloud and the user, between different sites of the same cloud provider, or indeed between different cloud providers. It is therefore important to keep applications near the data itself. This paper investig…
Role of Data Communications in Hybrid Cloud Costs
2011
Rapid adoption of cloud services in recent years has been driven by multiple factors, such as faster time-to-market and improved scalability enabled by public cloud infrastructure. Hybrid clouds, combining the in-house capacities with on-demand capacity of public clouds, achieve both the increased utilization rate of the in-house infrastructure and the limited use of more expensive public cloud, thereby lowering the total costs for the cloud user. In this paper, an analytical model of hybrid cloud costs is introduced, wherein the costs of computing and data communication are taken into account. Using this model, the costefficient division of the computing capacity between the private and th…
Complexity analysis of spectrum access strategies with channel aggregation in CR networks
2012
Cognitive radio has been introduced to increase spectrum utilization efficiency. To further improve bandwidth utilization of cognitive radio users, channel aggregation (CA) techniques can be adopted for spectrum access. In this paper, we analyze the complexity of three CA strategies, in terms of required amount of handshakes for channel adaptation due to primary and secondary user activities. Continuous time Markov chain models are developed to evaluate the total number of handshakes required per unit time by different CA strategies and the analytical results are validated by simulations. Numerical results reveal that the complexity of CA strategies depends on the capability and the design …
The node-depth encoding
2008
The node-depth encoding has elements from direct and indirect encoding for trees which encodes trees by storing the depth of nodes in a list. Node-depth encoding applies specific search operators that is a typical characteristic for direct encodings. An investigation into the bias of the initialization process and the mutation operators of the node-depth encoding shows that the initialization process has a bias to solutions with small depths and diameters, and a bias towards stars. This investigation, also, shows that the mutation operators are unbiased. The performance of node-depth encoding is investigated for the bounded-diameter minimum spanning tree problem. The results are presented f…
Low Degree of Separation Does Not Guarantee Easy Coordination
2012
In the times of increased global competition, software companies are forced to search for more effective development practices and often team up with onshore and offshore partners to develop faster and better products. In this paper we empirically explore a highly distributed onshore development project with a complex coordination structure. Our findings demonstrate that onshore development projects are not protected from coordination and communication challenges and task allocation complexities. Previously reported qualitative findings regarding organizational problems in this paper are supplemented with quantitative measurements of the true coordination delays and additional analysis of c…