A simple PI tuning rule for integrating plus dead time (IPDT) systems, with large parametric uncertainty, is developed. In order to deal with parametric uncertainty a family of plants is considered. The design specifi...
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A simple PI tuning rule for integrating plus dead time (IPDT) systems, with large parametric uncertainty, is developed. In order to deal with parametric uncertainty a family of plants is considered. The design specifications are upper bounds on the sensitivity and the complementary sensitivity functions, that must be satisfied for any element belonging to the plants set. When applied to a system without uncertainty (or with no significant uncertainty) the well-known SIMC tuning rule is recovered. To conclude, several examples are analyzed to illustrate the proposed tuning rule.
In this paper, it is proposed to use group communication cryptographic protocols as a new security paradigm. This new paradigm aims at redesigning the security of small cell communications over an insecure mobile back...
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ISBN:
(纸本)9781479940363
In this paper, it is proposed to use group communication cryptographic protocols as a new security paradigm. This new paradigm aims at redesigning the security of small cell communications over an insecure mobile backhaul. The Heterogeneous Networks are positioned and a review of the current security mechanisms and their flaws is provided. A security and performance comparison between the current mechanisms and our proposition is developed, and this comparison leads to new development opportunities to increase the security of the overall backhauling.
In this paper, we propose an ontology schema towards semantification provision of Twitter social analytics. The ontology is deployed over a publicly available service that measures how influential a Twitter account is...
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In this paper, we propose an ontology schema towards semantification provision of Twitter social analytics. The ontology is deployed over a publicly available service that measures how influential a Twitter account is, by combining its social activity and interaction over Twitter sphere. Apart from influential quantity and quality measures, the service provides a SPARQL endpoint where users can perform advance semantic queries through the RDFized Twitter entities (mentions, replies, hash tags, photos, URLs) over the semantic graph.
In public vs. private solutions (i.e. Cloud vs. In-house, or leased vs. Owned) for storage, both alternatives have their pros and cons. Cloud storage can easily adapt to the company needs, but exhibits a higher unit c...
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In public vs. private solutions (i.e. Cloud vs. In-house, or leased vs. Owned) for storage, both alternatives have their pros and cons. Cloud storage can easily adapt to the company needs, but exhibits a higher unit cost than in-house solutions. On the other hand, if the company relies on its own storage equipment, it must periodically purchase it on the basis of forecasts, which may prove imprecise and lead to idle equipment. In this paper, we propose a comparative evaluation tool for the two procurement approaches, where the cloud can play the role of either exclusive storage medium or supplement to in-house equipment (in the case of underestimation of storage needs). The tool considers the impact of equipment acquisition intervals and forecast accuracy over a long time horizon, adopting a Geometric Brownian Motion model for the evolution of storage capacity needs, it can be employed as a decision support tool for procurement decisions.
This paper introduces a pilot experience on the use of SCRUM methodology, borrowed from software project development and management, in group laboratory sessions during a university course of agent-based programming (...
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This paper introduces a pilot experience on the use of SCRUM methodology, borrowed from software project development and management, in group laboratory sessions during a university course of agent-based programming (fourth year of the Degree on computerscience in the University of Granada). It aims to foster a higher awareness of students and to enforce a series of transverse competencies like real, structured and self-organized teamwork, better planning of time during the laboratory sessions. As a side effect, it empowers leadership amongst the members of the team as well as it enables a high quality evaluation of students.
In this work, the 3D flow estimation problem is formulated in the 4D spatiotemporal frequency domain, and it is shown that 3D motion manifests itself as energy concentration along hyper-planes in that domain. Based on...
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ISBN:
(纸本)9781479957521
In this work, the 3D flow estimation problem is formulated in the 4D spatiotemporal frequency domain, and it is shown that 3D motion manifests itself as energy concentration along hyper-planes in that domain. Based on this, the construction and use of appropriate directional multidimensional "steerable" filters, which can extract directional energy in space-time, is proposed. Steerable filters have been constructed for up to 3 dimensions. We extend the relevant mathematical definitions to multiple dimensions and formulate filter-based algorithms for 3D flow estimation. Experimental results on simulated and real data verify the efficiency of the algorithms.
Whenever a chord is played in a musical instrument, the notes are not commonly played at the same time. Actually, in some instruments, it is impossible to trigger multiple notes simultaneously. In others, the player c...
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Modern scientific discovery is driven by an insatiable demand for computing performance. The HPC community is targeting development of supercomputers able to sustain 1 ExaFlops by the year 2020 and power consumption i...
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ISBN:
(纸本)9781479955008
Modern scientific discovery is driven by an insatiable demand for computing performance. The HPC community is targeting development of supercomputers able to sustain 1 ExaFlops by the year 2020 and power consumption is the primary obstacle to achieving this goal. A combination of architectural improvements, circuit design, and manufacturing technologies must provide over a 20x improvement in energy efficiency. In this paper, we present some of the progress NVIDIA Research is making toward the design of Exascale systems by tailoring features to address the scaling challenges of performance and energy efficiency. We evaluate several architectural concepts for a set of HPC applications demonstrating expected energy efficiency improvements resulting from circuit and packaging innovations such as low-voltage SRAM, low-energy signaling, and on-package memory. Finally, we discuss the scaling of these features with respect to future process technologies and provide power and performance projections for our Exascale research architecture.
Today, science is passing through an era of transformation, where the inundation of data, dubbed data deluge is influencing the decision making process. The science is driven by the data and is being termed as data sc...
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Today, science is passing through an era of transformation, where the inundation of data, dubbed data deluge is influencing the decision making process. The science is driven by the data and is being termed as data science. In this internet age, the volume of the data has grown up to petabytes, and this large, complex, structured or unstructured, and heterogeneous data in the form of "Big Data" has gained significant attention. The rapid pace of data growth through various disparate sources, especially social media such as Facebook, has seriously challenged the data analytic capabilities of traditional relational databases. The velocity of the expansion of the amount of data gives rise to a complete paradigm shift in how new age data is processed. Confidence in the data engineering of the existing data processing systems is gradually fading whereas the capabilities of the new techniques for capturing, storing, visualizing, and analyzing data are evolving. In this review paper, we discuss some of the modern Big Data models that are leading contributors in the NoSQL era and claim to address Big Data challenges in reliable and efficient ways. Also, we take the potential of Big Data into consideration and try to reshape the original operational- oriented definition of "Big science" (Furner, 2003) into a new data-driven definition and rephrase it as "The science that deals with Big Data is Big science.".
The Transmission Control Protocol (TCP) has evolved from its initial form defined in RFC 793 in 1981 to cope with the evolution of IP networks in general and of the Internet in particular. Over the years, several fact...
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The Transmission Control Protocol (TCP) has evolved from its initial form defined in RFC 793 in 1981 to cope with the evolution of IP networks in general and of the Internet in particular. Over the years, several factors have led to the design of successive TCP variants: the increasing disparity of end hosts, the variety of data links characteristics (Optical, wireless cellular or satellite), the increase of the delay-bandwidth product in data networks or the use of multiple paths at the same time. In this context, some TCP variants tune the congestion control and avoidance mechanisms to adapt them to specific situations while others make use of TCP options. In practice, such enhanced versions of TCP can be unusable because of the presence of intermediate elements such as firewalls along the path between the two end hosts. Such elements can indeed filter some TCP options or tamper with the way congestion is managed, introducing then unacceptable jitter in the IP flows. In such cases, most TCP variants are designed to fallback to a generic form of TCP. In many situations, this generic TCP version is not the best fit, while another TCP variant could be used to deal with this transient problem. To address this issue, we introduce an original offer/answer (O/A) mechanism allowing end hosts to identify dynamically a suitable TCP variant able to satisfy the specific constraints of each type of packet flows.
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