Search results for " Access"
showing 10 items of 776 documents
NECK DISSECTIONS: MISCONCEPTIONS, MALPRACTICE AND COMMON CONTROVERSIES
2007
B a c k g ro u n d. Neck metastases are the single most important prognostic factor in Head and Neck Squamous Cell Carcinoma. Wise approach to neck treatment is then mandatory to give a chanche for cure. Still, there are some issues about neck dissection that need to be clarified. M e t h o d s. Through a review of the literature and of everyday clinical observations, the following issues are discussed: Functional Neck Dissection, biopsies, nodal levels, Selective Neck Dissections, Spinal Accessory Nerve, neck dissection classification. R e s u l t s. Integration of historical, anatomical, clinical and surgical concepts and up-to-date knowledge can allow to understand how to behave in diver…
Towards Modelling Information Security with Key-Challenge Petri Nets
2009
Our global information society is based on distributed wide-area networks. Network security consists of the provisions made in an underlying computer network infrastructure, policies adopted by the network administrator to protect the network-accessible resources from unauthorized access, as well as continuous monitoring and measurement of the network security's effectiveness. In this paper, we describe the use of Petri nets in modelling network security. We propose a new hierarchical method for modelling network attacks and evaluating effectiveness of the corresponding defences. Our model is called Key-Challenge Petri Net (KCPN).
Adapting Downlink Power in Fronthaul-Constrained Hierarchical Software-Defined RANs
2017
Abstract The proof-of-concept software-defined radio access network (RAN) is not flexible enough due to the inherent delay and the necessity of high-capacity fronthaul links. We are hence motivated to propose a hierarchical software-defined RAN architecture, over which the base stations (BSs) are abstracted into multiple virtual local controllers while these local controllers are administered by a high-level controller. Under such a hierarchical network architecture, we particularly investigate in this paper how to adapt the BS transmit power over a long term according to the network dynamics under the constraints of mobile user queue stability and limited fronthaul capacity. We first formu…
Designing Frame Relay WAN Networks with Trade-Off between Link Cost and Performance
2014
This paper is focused on the problem of designing a Wide Area Network topology with trade-off between link cost and response time to users. The L2 technology chosen for the research is a Frame Relay based solution. The link capacities in the network and the routes used by packets are determined in a way to minimize network cost and response time at the same time. In FR networks link capacity corresponds directly to CIR parameter which makes the presented numerical results very useful in practice, especially during preliminary network design in the Design Phase of the PPDIOO methodology.
Dynamic packet scheduling performance in UTRA Long Term Evolution downlink
2008
In this paper we evaluate the performance of dynamic Packet Scheduling (PS) of 3GPP UTRAN Long Term Evolution (LTE) Downlink. Packet scheduling is of utmost importance in 3G LTE, because all traffic types with different Quality of Service requirements are competing of the resources. We present a decoupled time and frequency domain packet scheduling framework for LTE downlink. Simulation results with three basic packet scheduler combinations with different amount of fairness are presented in four different 3GPP macro simulation cases to show the both extremes in tradeoff between fairness and spectral efficiency. In addition, the effect of multiuser diversity on packet scheduling performance …
On Constructing Persistent Identifiers with Persistent Resolution Targets
2016
Persistent Identifiers (PID) are the foundation referencing digital assets in scientific publications, books, and digital repositories. In its realization, PIDs contain metadata and resolving targets in form of URLs that point to data sets located on the network. In contrast to PIDs, the target URLs are typically changing over time; thus, PIDs need continuous maintenance -- an effort that is increasing tremendously with the advancement of e-Science and the advent of the Internet-of-Things (IoT). Nowadays, billions of sensors and data sets are subject of PID assignment. This paper presents a new approach of embedding location independent targets into PIDs that allows the creation of maintena…
Technology Impact on Neutron-Induced Effects in SDRAMs : A Comparative Study
2021
International audience; This study analyses the response of synchronous dynamic random access memories to neutron irradiation. Three different generations of the same device with different node sizes (63, 72, and 110 nm) were characterized under an atmospheric-like neutron spectrum at the ChipIr beamline in the Rutherford Appleton Laboratories, UK. The memories were tested with a reduced refresh rate to expose more single-event upsets and under similar conditions provided by a board specifically developed for this type of study in test facilities. The board has also been designed to be used as a nanosatellite payload in order to perform similar tests. The neutron-induced failures were studi…
Single-Event Effects in the Peripheral Circuitry of a Commercial Ferroelectric Random Access Memory
2018
International audience; This paper identifies the failure modes of a commercial 130-nm ferroelectric random access memory. The devices were irradiated with heavy-ion and pulsed focused X-ray beams. Various failure modes are observed, which generate characteristic error patterns, affecting isolated bits, words, groups of pages, and sometimes entire regions of the memory array. The underlying mechanisms are discussed.
Methodologies for the Statistical Analysis of Memory Response to Radiation
2016
International audience; Methodologies are proposed for in-depth statistical analysis of Single Event Upset data. The motivation for using these methodologies is to obtain precise information on the intrinsic defects and weaknesses of the tested devices, and to gain insight on their failure mechanisms, at no additional cost. The case study is a 65 nm SRAM irradiated with neutrons, protons and heavy ions. This publication is an extended version of a previous study.
Fermi-Dirac correlations in Lambda pairs in hadronic Z decays
2000
Two-particle correlations of Lambda Lambda and pairs have been studied in multihadronic Z decays recorded with the ALEPH detector at LEP in the years from 1992 to 1995. The correlations were measured as a function of the four-momentum difference Q of the pair. A depletion of events is observed in the region Q 2 GeV the fraction of pairs with spin one is consistent with the value of 0.75 expected for a statistical spin mixture, whilst for Q pairs, where no Fermi-Dirac correlations are expected, the spin one fraction is measured to be consistent with 0.75 over the entire analysed Q range. (C) 2000 Elsevier Science B.V. All rights reserved.