73 research outputs found
Per-Priority Flow Control (Ppfc) Framework For Enhancing Qos In Metro Ethernet
Day by day Internet communication and services are experiencing an increase in variety and quantity in their capacity and demand. Thus, making traffic management and quality of service (QoS) approaches for optimization of the Internet become a challenging area of research; meanwhile flow control and congestion control will be considered as significant fundamentals for the traffic control especially on the high speed Metro Ethernet. IEEE had standardized a method (IEEE 802.3x standard), which provides Ethernet Flow Control (EFC) using PAUSE frames as MAC control frames in the data link layer, to enable or disable data frame transmission. With the initiation of Metro Carrier Ethernet, the conventional ON/OFF IEEE 802.3x approach may no longer be sufficient. Therefore, a new architecture and mechanism that offer more flexible and efficient flow and congestion control, as well as better QoS provisioning is now necessary
ASSESSING AND IMPROVING THE RELIABILITY AND SECURITY OF CIRCUITS AFFECTED BY NATURAL AND INTENTIONAL FAULTS
The reliability and security vulnerability of modern electronic systems have emerged as concerns due to the increasing natural and intentional interferences. Radiation of high-energy charged particles generated from space environment or packaging materials on the substrate of integrated circuits results in natural faults. As the technology scales down, factors such as critical charge, voltage supply, and frequency change tremendously that increase the sensitivity of integrated circuits to natural faults even for systems operating at sea level. An attacker is able to simulate the impact of natural faults and compromise the circuit or cause denial of service. Therefore, instead of utilizing different approaches to counteract the effect of natural and intentional faults, a unified countermeasure is introduced. The unified countermeasure thwarts the impact of both reliability and security threats without paying the price of more area overhead, power consumption, and required time.
This thesis first proposes a systematic analysis method to assess the probability of natural faults propagating the circuit and eventually being latched. The second part of this work focuses on the methods to thwart the impact of intentional faults in cryptosystems. We exploit a power-based side-channel analysis method to analyze the effect of the existing fault detection methods for natural faults on fault attack. Countermeasures for different security threats on cryptosystems are investigated separately. Furthermore, a new micro-architecture is proposed to thwart the combination of fault attacks and side-channel attacks, reducing the fault bypass rate and slowing down the key retrieval speed. The third contribution of this thesis is a unified countermeasure to thwart the impact of both natural faults and attacks. The unified countermeasure utilizes dynamically alternated multiple generator polynomials for the cyclic redundancy check (CRC) codec to resist the reverse engineering attack
Improving Degree of Delignification and Selectivity of Oxygen Delignification of Southern Pine Kraft Pulp
Oxygen delignification is a pre-bleaching stage that provides environmental benefits for bleached pulp production by replacing about 50% of the chlorine-based bleaching chemicals with oxygen. The resulting reduction in chlorine-based chemicals leads to a significantly lower release of chlorinated organics in the pulp bleaching effluent. However, the main disadvantage of applying oxygen delignification is the low delignification/cellulose degradation selectivity compared to chlorine dioxide bleaching. Modern conventional oxygen delignification is limited at level 60% delignification to maintain an acceptable cellulose Degree of Polymerization (DP) and thus fiber strength as indicated by the pulp intrinsic viscosity. The increase in the degree of delignification from 60 to 80% leads to a reduction by a factor 2 of the required bleaching chemicals and also reduces the environmental impact of the bleach plant effluent by at least a factor of two. However, to achieve this increase in the degree of delignification the delignification/cellulose degradation selectivity must be improved, and therefore the objective of the present research is to understand and improve the selectivity especially at high degrees of delignification.
The technical objective of the present PhD project was to perform extended oxygen delignification up to 80% of conventional Southern Pine kraft pulp (about 24 kappa) while maintaining acceptable cellulose DP as calculated from the measured pulp intrinsic viscosity. More importantly, the fundamental objective of the research is to understand how to increase the delignification/cellulose degradation selectivity during oxygen delignification of conventional softwood kraft pulp (about 24 kappa) in particular at very high degrees of delignification.
In the present study, we found that the oxygen delignification of industrial softwood pulp consists of two contributions; phenolic delignification and alkaline leaching delignification.
In addition, we could extend the oxygen delignification up to 80% of conventional Southern Pine kraft pulp (about 24.4 kappa number) while maintaining acceptable intrinsic viscosity (\u3e700 mL/g) in the presence of 2.186 g/L Na2CO3 at 100 oC for 90 minutes of oxygen delignification. But, for the conventional kraft pulp, the selectivity is not affected by the addition of 100 ppm NaBH4 because of the absence of carbonyl groups on cellulose in the kraft pulp, and no improvement in pulp viscosity and selectivity is seen
Supraconductivité et ordre de charge dans les bicouches de graphène moirées
Abstract: The recent discovery of a correlated insulating state and superconductivity in twisted bilayer graphene (TBG) has opened a new platform for studying unconventional superconductivity. superconductivity appears for TBG at an angle ∼ 1.08◦ for a very low carrier density of about 1011 cm−2, with a Tc of 1.7 K. The misalignment of the two layers of graphene at the magic angle creates a periodic lattice called the moiré lattice. The effective model we use to describe this system is based on the moiré lattice and was proposed by Kang and Vafek. This model includes four Wannier orbitals located at the honeycomb lattice sites. In addition to hopping terms between these orbitals, we also add intra-orbital and inter-orbital interactions to the Hamiltonian and use a Hubbard or extended Hubbard model to describe the system. Our calculations are based on quantum cluster methods. To investigate the superconductivity we tile the lattice by the four site clusters immersed among six bath orbitals and use the CDMFT method. In the study of the correlated insulating phase, we use the VCA method and select clusters consisting of 12 Wannier orbitals so that we can define inter-orbital interactions in a cluster. We obtain a non-zero p±ip order parameter for superconductivity in a wide range of carrier densities, which is consistent with the experimental observations. Experimental measurements show that the system has a gap in the vicinity of n = 0.5 and n = 1.5 and behaves like a Mott insulator. So we expect that the superconductivity to be suppressed or eliminated in these ranges of densities, which is confirmed by our calculations. d±id is another nonzero superconductor order parameter that we found. The size of this singlet order parameter is smaller than the p ± ip. By calculating the Patthoff functional for two kinds of superconductors, we conclude that p±ip superconductivity has a lower free energy and therefore is the dominant phase between the two. In addition to the superconducting phase, the study of the strongly correlated insulating phases observed in the experiment was another objective of this thesis. Our calculations confirm the existence of these phases at quarter-, half- and three-quarter filling. Further computations show that the insulating phase at quarter-filling is not a charge density wave and that the insulating phase at half-filling is not antiferromagnetic.La découverte récente d’un état corrélé isolant et de la supraconductivité dans la bicouche
de graphène moirée (TBG) a ouvert un nouveau canal dans l’étude de la supraconductivité
non conventionnelle. Dans ce système, la supraconductivité apparaît à un
angle de torsion ∼ 1.08◦ et à très faible densité de porteurs de 1011 cm−2, avec une Tc
de 1.7 K.
Le défaut d’alignement des deux couches de graphène crée un super-réseau appelé
réseau moiré. Le modèle effectif utilisé pour décrire ce système est basé sur ce réseau
moiré et a été proposé par Kang et Vafek. Ce modèle comporte 4 orbitales de Wannier
centrées sur les sites d’un réseau en nid d’abeille. En plus des termes de saut entre ces
orbitales, nous ajoutons des interactions (intra- et inter-orbitales) et utilisons le modèle
de Hubbard étendu pour modéliser ce système. Nos calculs reposent sur les méthodes
d’amas quantiques. Pour étudier la supraconductivité, nous utilisons un dallage
du réseau par des amas de quatre sites couplés à six sites de bain dans la théorie du
champ moyen dynamique sur amas (CDMFT). Pour l’étude des phases isolantes, nous
utilisons plutôt la méthode de l’amas variationnel (VCA) sur un amas de douze sites, de
sorte que les interactions étendues peuvent être comprises minimalement dans l’amas.
Pour une large gamme de densités, cohérente avec les observations, nous trouvons
un état supraconducteur de type p ± ip. Les expériences montrent que le système possède
un gap spectral au voisinage de n = 0.5 et n = 1.5 et se comporte comme un isolant
de Mott. On s’attend donc à ce que la supraconductivité soit atténuée ou éliminée près
de ces densités, ce qui est confirmé par nos calculs. On trouve aussi un état supraconducteur
d ±id comme solution secondaire, avec un paramètre d’ordre plus petit. Un calcul
de la fonctionnelle de Potthoff dans ces deux solutions nous permet d’affirmer que l’état
p±ip a une énergie plus basse et constitue donc la phase dominante. L’étude des phases
isolantes était un deuxième objectif de cette thèse. Nos calculs démontrent l’existence
de phases isolantes de Mott au quart remplissage et au demi-remplissage. Des calculs
additionnels montrent que l’état isolant à quart rempli n’est pas une onde de densité de
charge et que l’état isolant au demi-remplissage n’est pas antiferromagnétique
Distributed Hierarchical IDS For MANET Over AODV+.
In this paper, we introduce background knowledge of wireless ad hoc networking mobile ad hoc network (MANET) as well as intrusion detection system (IDS) and mobile agents. This research study surveys, studies and compares the existing intrusion detection based on mobile agent for mobile ad hoc networks. Based on our best knowledge from previous researches we design distributed hierarchical /D^S inclusive of network-based and host-based intrusion detection system with due consideration to their characteristics on ad hoc on4emand distance vector routing protocol (AODV+)
Post anesthetic shivering in children: incidence and causative factors
چکیده: زمینه و هدف: بیماران در طی بیهوشی حرارت از دست می دهند و پیدایش لرز روشی برای مقابله با آن است. تاکنون مطالعات متعددی در مورد لرز در بالغین انجام شده، ولی میزان این مطالعات در کودکان محدود است. لذا این مطالعه با هدف بررسی شیوع لرز پس از بیهوشی در کودکان و عوامل مربوط به آن انجام شد. روش بررسی: در این مطالعه توصیفی - تحلیلی ٢٠٠ کودک سه ماهه تا چهارده ساله در اطاق بهبودی از نظر عوامل زمینه ای، دریافت پیش داروی بیهوشی، روش بیهوشی، مدت زمان بیهوشی، درجه حرارت بیمار در اطاق بهبودی و درجه حرارت اطاق بهبودی مورد بررسی قرار گرفتند. پس از جمع آوری داده ها با کمک پرسشنامه، اطلاعات با استفاده از تست های آماری کای دو و اسپیرمن مورد تجزیه و تحلیل قرار گرفتند. یافته ها: تعداد کل موارد مشاهده شده لرز ٧ (١٤ نفر) بود. شیوع لرز در بیهوشی استنشاقی (6/13) به صورت معنی دار بیشتر از بیهوشی وریدی (صفر) بود (05/0
Evaluation of the Clinical Performance of Nurses Employed in the Neonatal Intensive Care Units
Introduction: Nurses are as the most important health care providers who require extensive knowledge and skills in this field. Despite the high importance of the issue, our knowledge of the current status of clinical performance and levels of nursing skills in the neonatal intensive care units is very low. The present study was done with the aim of determining the status of clinical performance of neonatal nurses in the NICU. Methods: The present research is a descriptive study, through which the clinical performances of 96 neonatal nurses were observed in eight areas. Data collection was done using a researcher-made Scale. The data were analyzed with SPSS version 21. Results: The neonatal nurses’ clinical performances were acceptable (69.74%) in all the areas which includes vital signs control, daily cares, respiratory cares, infants feed, vessels' access, medicine prescription, phototherapy and using required equipment for neonates (such as warmer, Infusion pump, Defibrillator, Incubator, Ventilator and Phototherapy).The highest and lowest practices were assessed in the fields of infant nutrition (84.11%) and equipment utilized (51.93%), respectively. Conclusions: The nursing skills in the study areas seems within an acceptable range, which could be due to the NICU nurses’ interests in this field. In order to improve the performance of nurses in areas where there is a weakness, we suggest considering the importance of these care and disadvantages due to negligence
A DISTRIBUTED RESOURCE-MANAGEMENT APPROACH IN MANETS
Mobile ad hoc network (MANET) is an infrastructure less network, in where all mobile nodes are free for any movement to any side. Thus the network is going toward zero configurations that would create some problems. Ad hoc network is faced with various limitations that need to be considered among design and implementation of any protocol for it. Service Advertisement (SA) is one of the important services that are offered in each network. To have a fast service discovery in a network with minimum energy consumption, distributing of services’ information and their management play important roles. In this paper for avoiding packet flooding in the MANET we used Cluster Based Routing Protocol (CBRP). For reducing amount of communication messages we moved service advertisement from application layer to routing layer. Thus we distribute the active services in the network among clustered nodes. However, the results of our experiment show that our method does not add any extra overhead to the network
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