2,869 research outputs found
Clocking and Scientific Research: the opinion of the scientific community.
The following chapters assemble the opinions and standpoints of italian and foreign scientists with regard to the assessment of results of research work.
This collection was inspired by a manifesto signed by researchers from the Istituto Nazionale di Fisica Nucleare (INFN) and associated universi- ties, which was distributed to the international scientific community. The circumstance giving rise to this intellectual mobilization was the absence of any sign that the promised experimentation to evaluate work performed by government researchers was to start. The scientific community was prompt in giving its support as this document testify.
Research activity is assessed according to its content and results. Italian law, however, stipulates that for all government agencies, hence research in- stitutes such as INFN, performance should be monitored using pre-defined objective procedures. For all government institutes and agencies this assess- ment is based on clocking in and out
Multistage Switching Architectures for Software Routers
Software routers based on personal computer (PC) architectures are becoming an important alternative to proprietary and expensive network devices. However, software routers suffer from many limitations of the PC architecture, including, among others, limited bus and central processing unit (CPU) bandwidth, high memory access latency, limited scalability in terms of number of network interface cards, and lack of resilience mechanisms. Multistage PC-based architectures can be an interesting alternative since they permit us to i) increase the performance of single software routers, ii) scale router size, iii) distribute packet manipulation and control functionality, iv) recover from single-component failures, and v) incrementally upgrade router performance. We propose a specific multistage architecture, exploiting PC-based routers as switching elements, to build a high-speed, largesize,scalable, and reliable software router. A small-scale prototype of the multistage router is currently up and running in our labs, and performance evaluation is under wa
Las inundaciones en la cuenca del Río Quinto - Salado del Sur : Sus causas
En la presente ponencia se discuten los diferentes aspectos que causan inundaciones en la Cuenca del Rio Quinto-Salado del Sur y se problematizan las distintas soluciones aportadas hasta el momento.Evento también conocido bajo el nombre de "II Jornadas Platenses de Geografía"Facultad de Humanidades y Ciencias de la Educació
Joint delay and power control in single-server queueing systems
Abstract—Many power-aware resource allocation problems in packet networks can be modeled as single-server queueing systems, in which the power consumption depends on the actual service rate. We consider the scenario in which the queue service rate is controlled to minimize server power consumption. We show that power control methods that tune the service rate by using the queue length or the arrival rate exhibit a non-monotonic curve of delay vs. load. This may lead to malfunctioning in endto-end flow/congestion control protocols, which are based on the assumption that delays increase with increasing load. We propose a new policy, in which the service rate is changed while keeping almost flat the delay curve, which permits to achieve a close-tooptimal trade-off between power and delay. I
Scalability of ONOS reactive forwarding applications in ISP networks
Software Defined Networking (SDN) is a powerful approach that enhances network control and management, and provides a flexible way to develop network applications. However, scalability of SDN networks is an important concern for many network operators. The main peculiarities of SDN when applied to an Internet Service Provider (ISP) network are the large geographical extension and the need of in-band transmission of control traffic. Therefore, the control traffic exchanged between the SDN controller and the network nodes must be carefully evaluated for the network design and dimensioning.
We consider an ISP network controlled by the recently ONOS (Open Network Operating System) controller developed by ON.Lab. We devise a quantitative model to compute the exact number of exchanged OpenFlow messages and the corresponding bandwidth needed to install a traffic flow when running the default ONOS layer-2 forwarding applications. We compute also the exact number of flow rules installed in each switch. We show the general applicability of our models for a Point Of Presence (POP) network and for a large set of real nation-wide and world-wide ISP networks.
Our quantitative models can be used for a safe network planning also when the network applications are not fully reactive
Main features and control strategies to reduce overcrowding in emergency departments. A systematic review of the literature
Purpose: Overcrowding is a problem that affects emergency departments (ED) all over the world; it occurs due to a disproportion
between user demand and the physical, human and structural resources available. Essential prerequisites to assessing and managing the
phenomenon are its accurate measurement and an understanding of its impact. The objective of this systematic review is to identify the
characteristics of the problem, analyzing the proposed strategies aimed at improving patient flow, delay in services provided and
overcrowding of emergency departments.
Methods: To achieve our objectives, a manual computerized search was performed in the bibliographic databases using as keywords
“Emergency Department”, “Overcrowding”, “Emergency Room”, “Emergency Service”, “Emergency Unit”“,Emergency Ward”,
“Emergency Outpatient Unit”, “Emergency Hospital”, “Crowding”, “Mass Gathering”, “Management” and “Comprehensive Health
Care”. Two independent reviewers analyzed abstracts, titles and full text articles for admissibility, according to the selected inclusion
and exclusion criteria.
Results: The process lead to include 19 articles. It was possible to group the solutions proposed in five categories: work organization,
investment in primary care, creation of new dedicated professional figures, work and structural modifications and implementation of
predictive simulation models using mathematical algorithms.
Conclusion: The most effective measures to guarantee an improvement in the flow of patients are represented by both improving the
efficiency of human resources and by developing predictive mathematical models, regardless of the type of hospital and its location.
Considering the complexity of EDs and the multiple characteristics of overcrowding and that the causes of crowding are different and
site-specific, a careful examination of the specifics of each ED is necessary to identify improving fields
Routine invasive mediastinal staging of lung cancer in elderly patients without lymph adenopathy on pet-ct scan: Is an appropriate choice?
We have reviewed the literature to clarify if routine invasive mediastinal staging is indicated also in Stage I elderly patients screened with PET/CT scan. Nineteen papers were chosen to answer the question. Occult pN2 disease was < 10% in five papers; between 10-16% in four papers; and > 16% in four papers.Significant risk factors for occult pN2 disease are the SUV value of primary tumor (seven papers), central tumor (four papers), tumor > 3 cm (five papers), adenocarcinoma histology (five papers) and cN1 disease(two papers). Two papers found that unexpected pN2 patients had a better survival than cN2 patients operated after induction therapy. Invasive mediastinal staging is recommended also in cN0 patients with central tumor or with peripheral tumor > 3 cm
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