Search results for "DMIS"
showing 10 items of 286 documents
A Migration Path for the Internet: From Best-Effort to a QoS Capable Infrastructure by Means of Localized Admission Control
2000
Looking back at many proposals appeared on the scene in these years, a fundamental lesson to be learned is that their success or failure is strictly tied to their backward compatibility with existing infrastructures. In this paper, we consider the problem of providing explicit admission control decisions for QoS aware services. We rely the decision to admit a new flow upon the successful and timely delivery, through the Internet, of probe packets independently generated by the end points. Our solution, called GRIP (Gauge&Gate Realistic Internet Protocol), is fully distributed and scalable, as admission control decisions are taken at the edge network nodes, and no coordination between router…
Call Admission Control in Single and Two-Tier Cellular Networks
2010
We consider four strategies for call admission control (CAC) in single and two-tier cellular networks, which are designed to ensure advantage of handover calls: dynamic redundancy (cutoff priority scheme), partial dynamic redundancy (fractional guard channel scheme), static redundancy (rigid division-based CAC scheme) and restriction of the number of new calls admitted (new call bounding scheme). We show the advantage of dynamic reservation by numerical analysis. We strictly prove it in the case of two-channel system with losses.
An Integrated Multi-service Software Simulation Platform: SIMPSONS Architecture
2005
This paper describes SIMPSONS (SIp and MPls Simulations On NS-2), which is a software platform for simulating multiple network scenarios, such as Telephony Over IP (TOIP), and multi-services networks extending the functionalities of Network Simulator NS-2. The innovative aspects of SIMPSONS is the complete integration of control protocols and traffic engineering mechanisms inside the same simulation tool. In fact, next generation networks must meet basically two fundamental requirements: support of Quality of Service (QoS) and Traffic Engineering (TE) functionalities. SIMPSONS is able to simulate DiffServ, MPLS, OSPF and SIP and their interaction in everything TOIP scenario. So with this po…
Is Admission-Controlled Traffic Self-Similar?
2002
It is widely recognized that the maximum number of heavy-tailed flows that can be admitted to a network link, while meeting QoS targets, can be much lower than in the case of markovian flows. In fact, the superposition of heavy-tailed flows shows long range dependence (self-similarity), which has a detrimental impact on network performance. In this paper, we show that long range dependence is significantly reduced when traffic is controlled by a Measurement-Based Admission Control (MBAC) algorithm. Our results appear to suggest that MBAC is a value added tool to improve performance in the presence of self-similar traffic, rather than a mere approximation for traditional (parameter-based) ad…
Note di Abū Naṣr al-Fārābī sulla verità e falsità dell’astrologia
2020
Il presente contributo propone l’introduzione, la traduzione italiana e il commento delle Note sulla verità e falsità dell’astrologia (Nukat fī mā yaṣiḥḥu wa-mā lā yaṣiḥḥu min aḥkām al-nuǧūm) di Abū Naṣr al-Fārābī (m. 950). Tale scritto non è stato trasmesso direttamente dal suo autore né ci è giunto nella sua redazione definitiva, bensì in forma di appunti ricopiati da un grammatico di nome Abū Isḥāq al-Baġdādī. In trenta brevi capitoli al-Fārābī spiega ciò che è accessibile e ciò che è inaccessibile alle predizioni astrologiche e quali aspetti di tale scienza sia opportuno accogliere o respingere.
PPF dependent fixed point results for triangular $alpha_c$-admissible mappings
2014
We introduce the concept of triangular $alpha_c$-admissible mappings (pair of mappings) with respect to $η_c$ nonself-mappings and establish the existence of PPF dependent fixed (coincidence) point theorems for contraction mappings involving triangular $alpha_c$-admissible mappings (pair of mappings) with respect to $η_c$ nonself-mappings in Razumikhin class. Several interesting consequences of our theorems are also given.
On fixed points of alpha-eta-psi-contractive multifunctions
2014
Recently Samet et al. [B. Samet, C. Vetro, P. Vetro, Fixed point theorem for alpha-psi-contractive type mappings, Nonlinear Anal., 75 (2012), 2154{2165] introduced the notion of alpha-psi-contractive type mappings and established some fixed point theorems in complete metric spaces. Succesively, Asl et al. [J.H. Asl, SH. Rezapour, N. Shahzad, On fixed point of alpha-contractive multifunctions, Fixed Point Theory Appl., 2012, 212 (2012)] introduced the notion of alpha_*-psi-contractive multifunctions and give a fixed point result for these multifunctions. In this paper we obtain certain new fixed point and common fixed point theorems via alpha_*-admissible multifuncions with respect to eta. T…
Coherent Conditional Previsions and Proper Scoring Rules
2012
In this paper we study the relationship between the notion of coherence for conditional prevision assessments on a family of finite conditional random quantities and the notion of admissibility with respect to bounded strictly proper scoring rules. Our work extends recent results given by the last two authors of this paper on the equivalence between coherence and admissibility for conditional probability assessments. In order to prove that admissibility implies coherence a key role is played by the notion of Bregman divergence.
Admissible perturbations of alpha-psi-pseudocontractive operators: convergence theorems
2015
In the last decades, the study of convergence of fixed point iterative methods has received an increasing attention, due to their performance as tools for solving numerical problems. As a consequence of this fact, one can access to a wide literature on iterative schemes involving different types of operators; see [2, 4, 5]. We point out that fixed point iterative approximation methods have been largely applied in dealing with stability and convergence problems; see [1, 6]. In particular, we refer to various control and optimization questions arising in pure and applied sciences involving dynamical systems, where the problem in study can be easily arranged as a fixed point problem. Then, we …