Slow manifolds for stochastic koper models with stable Lévy noises

The Koper model is a vector field in which the differential equations describe the electrochemical oscillations appearing in diffusion processes. This work focuses on the understanding of the slow dynamics of a stochastic Koper model perturbed by stable Lévy noise. We establish the slow manifold for a stochastic Koper model with stable Lévy noise and verify exponential tracking properties. We also present two practical examples to demonstrate the analytical results with numerical simulations

Gestion de la mobilité pour l'internet du futur centré autour de l'information

L'Internet d'aujourd'hui a traversé série de changements évolutionnaires dans les quarante ou cinquante dernières années. Il a été conçu pour un réseau avec des nœuds fixes. Au début, le modèle de communication de l'Internet a été basé sur le réseau téléphonique (considéré comme 1er Génération Internet). Plus tard, il a été mis à jour comme un modèle client-serveur où la communication des systèmes d'échanger des données sur des liaisons dédiées. Cette 2ème génération Internet, au cours des années, a été contestée par de nombreux problèmes tels que la congestion du réseau, panne de chemin, les attaques DOS, gestion de la mobilité pour les réseaux sans fil, etc. Les utilisateurs d'Internet recherchent toujours des informations, indépendamment de la localisation (nœud ou serveur) où il se trouve ou stockées. Cette approche est la base d'une architecture où l'information est considérée comme l'unité primaire. Ces réseaux, en général, sont appelés en tant que Network of Information (NetInf), où l'information prend une position centrée remplaçant l'approche centrée sur nœud comme dans l'Internet aujourd'hui. Les problèmes rencontrés par l'Internet aujourd hui, mentionné ci-dessus, peuvent être traitées avec une approche unificatrice en mettant l'information au centre de l'architecture du réseau. À l'échelle mondiale, cette conception de l'architecture réseau est nommée Future Information Centric Internet . En parallèle, l'utilisation de l'Internet mobile a été augmentée durant la dernière décennie. Il a été environ 1,2 milliard abonnements de mobile broad band pour 2,4 milliards d utilisateurs d'Internet en 2011. En raison d augmentation de l'efficacité spectrale et ubiquitaire disponibilité de la connectivité cellulaire, la mobilité et la connectivité transparente est désormais considérée comme des produits de base la vie quotidienne. Néanmoins, en cas d'Internet, les solutions de mobilité basées sur IP ne peuvent pas rattraper son retard dans la performance avec l'évolution rapide des réseaux cellulaires. Par conséquent, l'un des principaux objectifs pour l'internet du futur est de concevoir des systèmes de gestion de mobilité qui permettent de surmonter les problèmes dans les réseaux sans fil tels que handover et la gestion de la localisation, multihoming, sécurité, etc. Dans cette thèse, nous avons proposé une solution de gestion de mobilité dans les réseaux sans fil dans le cadre du Information Centric Networking (ICN) en général et dans le contexte ne NetInf en particulier. NetInf est une architecture du Futur Internet basée sur le concept du ICN. Nous proposons un nœud mobile qui s appelle NetInf Mobile Node (NetInf MN). L'architecture de ce nœud est compatible avec l'architecture d'Internet basée sur TCP/TP. Cette conception de l'architecture travaille en collaboration avec Central Control Unit (CCU) pour améliorer les performances en cas de handover dans les réseaux sans fil. La Virtual Node Layer (VNL) algorithme explique comment les différents modules de NetInf MN et des unités CCU travaillé ensemble. La modèle mathématique basé sur Théorie de Jeu et Renforcement Learning (CODIPAS-RL) montre comment handover et data relaying sont géré dans les réseaux sans fil. Les résultats des simulations montrent que le modèle proposé réalise à la fois de Nash et de Stackelberg équilibres alors que le CODIPAS-RL régime atteint un optimum global. Enfin, comme un exemple de cas d'utilisation de l'architecture NetInf, nous proposons le NetInf Email Service qui ne requiert pas des serveurs et ports dédiés contrairement au service e-mail existante. L'utilisation de clés asymétriques comme l'ID de l'utilisateur est la caractéristique unique proposée pour ce service. Le NetInf Email service architecture présenté, explique comment différents éléments architecturaux travail ensemble. Nous discuter des défis différents et des besoins relatifs à ce service. Le prototype développé pour NetInf sera utilisée pour la mise en œuvre de ce serviceThe contemporary Internet ecosystem today has gone through series of evolutionary changes during the last forty or fifty years. Though it was designed as a network with fixed nodes, it has scaled well enough with the development of new technologies both in fixed and wireless networks. Initially, the communication model of the Internet was based on the telephone network (and can be considered as the 1st Generation Internet). Later, its transition as a client-server model made it a network where communication systems exchange data over dedicated links. This 2nd Generation Internet, over the years, has been challenged by many problems and issues such as network congestion, path failure, DOS attacks, mobility issues for wireless networks, etc. The Internet users always look for some information, irrespectively where it is located or stored. This approach is the basic building block for a network architecture where information is considered as the premier entity. Such networks, in general, are termed as Information Centric Network (ICN), where information takes centric position superseding the node centric approach like in the current Internet. The problems faced by the current Internet architecture, mentioned above, can be handled with a unifying approach by putting the information at the centre of the network architecture. On a global scale, this network architecture design is termed as the Future Information Centric Internet. Similarly, Mobile Internet usage has increased overwhelmingly in the last decade. There has been an estimated 1.2 billion mobile broad-band subscriptions for 2.4 billion Internet users in 2011. Because of the increased spectrum efficiency and ubiquitous availability of cellular connectivity, the seamless mobility and connectivity is now considered as daily life commodity. However, in the case of the Internet, IP based mobility solutions cannot catch up in performance with the fast evolution of cellular networks. Therefore, one of the primary goals for the Future Internet is the design of mobility management schemes that overcome the issues in wireless networks such as handover and location management, multihoming, security, etc. In this thesis, we have proposed a mobility management solution in wireless networks in the context of ICN in general and in the context of Network of Information (NetInf) in particular. NetInf is ICN-based Future Internet architecture. We propose a NetInf Mobile Node (NetInf MN) architecture which is backward compatible with the current Internet architecture as well. This cross architecture design for mobility support works closely with Central Control Unit (CCU) (network entity) for improved performance in case of handover management in wireless networks. The Virtual Node Layer (VNL) algorithm explains how different modules of NetInf MN and CCU units work together. The game theoretical and Reinforcement Learning (CODIPAS-RL) scheme based mathematical model shows how handover management and data relaying in the wireless networks can increase the network coverage through cooperative diversity. Simulation results show that the proposed model achieves both Nash and Stackelberg equilibria where as the selected CODIPAS-RL scheme reaches global optimum. Finally, as a use case example of NetInf architecture, we propose the NetInf Email service that does not require dedicated servers or dedicated port unlike the current email service. The use of asymmetric keys as user's ID is the unique feature proposed for this service. The NetInf email service architecture framework presented, explains how different architectural components work together. We discuss different challenges and requirements related to this service. The prototype developed for the Network of Information will be used for the implementation of this serviceEVRY-INT (912282302) / SudocSudocFranceF

Neuro-Fuzzy Based High-Voltage DC Model to Optimize Frequency Stability of an Offshore Wind Farm

Lack of synchronization between high voltage DC systems linking offshore wind farms and the onshore grid is a natural consequence owing to the stochastic nature of wind energy. The poor synchronization results in increased system disturbances, grid contingencies, power loss, and frequency instability. Emphasizing frequency stability analysis, this research investigates a dynamic coordination control technique for a Double Fed Induction Generator (DFIG) consisting of OWFs integrated with a hybrid multi-terminal HVDC (MTDC) system. Line commutated converters (LCC) and voltage source converters (VSC) are used in the suggested control method in order to ensure frequency stability. The adaptive neuro-fuzzy inference approach is used to accurately predict wind speed in order to further improve frequency stability. The proposed HVDC system can integrate multiple distributed OWFs with the onshore grid system, and the control strategy is designed based on this concept. In order to ensure the transient stability of the HVDC system, the DFIG-based OWF is regulated by a rotor side controller (RSC) and a grid side controller (GSC) at the grid side using a STATCOM. The devised HVDC (MTDC) is simulated in MATLAB/SIMULINK, and the performance is evaluated in terms of different parameters, such as frequency, wind power, rotor and stator side current, torque, speed, and power. Experimental results are compared to a conventional optimal power flow (OPF) model to validate the performance.© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

MRI Guided Stereotactic Biopsies or Aspirations in Deep Seated Brain Lesions: An Experience of 146 Cases at Nishtar Hospital, Multan

Objective: To determine frequency of positive biopsies or aspirates and safety in deep seated brain lesion, with use of Magnetic Resonance Imaging compatible stereotactic system.Study Design: Prospective cross sectional.Setting: The study was performed at Neurosurgery Department Nishtar Hospital, Multan.Duration of Study: From 01-07-2008 to 30-06-2012.Material and Methods: A total of 146 patients of age between 12 – 18 years of either sex having deep, intrinsic cystic lesion of the brain less or equal to 4 cm2 in size and excluding the extensively vascular lesion diagnosed on Computed Tomography and Magnetic Resonance Imaging underwent Stereotactic biopsy or aspiration with Mag-netic Resonance Imaging compatible Leksell’s stereotactic system. The tissue specimens were analyzed by stan-dard histopathological methods. The safety was measured in context of absence of complications i.e. hemorrhage, new onset of neurological deficit and fits. Data was analyzed via computer software SPSS 10 version for win-dows.Results: Among 146 patients with deep seated cystic brain lesions were selected for aspiration by using MRI guided stereotactic system. Their age ranged from 12 years to 80 years with Mean = 37.73 ± Standard deviation (SD) = 18.12. Among them 86 (58.9%) were male and 60 (41.1%) female. Biopsies or aspirates were positive in 136 (93.2%) cases while negative in 10 (6.8%) cases.Conclusion: We conclude that MRI assisted stereotactic brain aspiration is safe and effective procedure with a high diagnostic yield at our center

In vitro Studies on Anti-diabetic and Anti-ulcer Potentials of Jatropha gossypifolia (Euphorbiaceae)

Purpose: To evaluate α-glucosidase and α-chymotrypsin enzyme inhibitory activity of Jatropha gossypifolia as a probable remedy for the management of diabetes and ulcer.Methods: Different extracts and fractions of the root, leaf and stem bark of the plant were screened for their α-glucosidase and α-chymotrypsin inhibitory activity using standard in vitro inhibition assays. Acarbose and chymostatin were used as positive control, respectively.Results: n-Butanol and ethyl acetate fraction showed maximum enzyme inhibition for α-glucosidase with 67.93 ± 0.66 and 67.67 ± 0.71 % and half maximal concentration (IC50) of 218.47 ± 0.23 and 213.45 ± 0.12 μg/ml, respectively. Dichloromethane and ethyl acetate leaf fractions exhibited maximum α-chymotrypsin inhibition activity of 85.08 ± 0.38 and 83.87 ± 0.70 %, and IC50 of 133.1 ± 0.68 and 134.5 ± 0.12 μg/ml, respectively, Acarbose exhibited enzyme inhibition activity of 92.14 ± 0.38 % with IC50 of 38.24 ± 0.1 μg/ml, while chymostatin exhibited 93.67 ± 0.38 % enzyme inhibition and IC50 of 8.24 ± 0.11 μg/ml.Conclusion: The presence of bioactive secondary metabolities with enzyme-inhibiting activity lends some support for the traditional use of this plant in the management of diabetes and ulcer. However, further investigation of the plant including identification of its active components is required.Keywords: α-Chymotrypsin, α-Glucosidase, Inhibition, Jatropha gossypifolia, Anti-diabetic, Anti-ulce

IoT smart health security threats

The Internet of things (IoT) is an active area in the current research community due to the improvement in mobile computing and wireless networks. Currently, the IoT is involved in many fields like smart cities, smart health monitoring, smart tracking, and smart factory; therefore, it is introducing new research opportunities and industrial revolutions. Smart health, in particular, is very important and trendy domain for researchers and practitioners due to its continuous monitoring of health of patients. The objective of smart health is to provide medical facilities to patients at anytime and anywhere. The smart health monitoring systems are mostly connected with the wireless network medium that is extremely vulnerable for threats. However various attacks are observed that can endanger these health monitoring applications and systems. These attacks include Denial of Service (DoS) Attack, Fingerprint and Timing-based Snooping, Router Attack, Select and Forwarding attack, Sensor attack and Replay Attack. In this paper, we discuss these attacks with their impact on health monitoring systems with some suggestive measures from our research findings

Antihyperlipidemic and Hepatoprotective Activity of Dodonaea viscosa Leaves Extracts in Alloxan-Induced Diabetic Rabbits (Oryctolagus cuniculus)

Hyperlipidemia is associated with diabetes and hepatotoxicity has emerged as a common clinical complication by antidiabetics. The present study was conducted to determine the antihyperlipidemic and hepatoprotective activity of Dodonaea viscosa leaves extracts in the alloxan-induced diabetic rabbits. The rabbits (n = 70) were divided into seven groups including normal and diabetic control, the remaining were aqueous, aqueous:methanol (70:30), aqueous:methanol (50:50), aqueous: methanol (30:70), and methanol extracts given for 30 days. Serum levels of triglycerides, total cholesterol, LDL-cholesterol, HDL-cholesterol, ALT and AST were estimated by using commercially available kits. The oral administration of aqueous:methanol (70:30) extract of the Dodonaea viscosa leaves significantly (P<0.01) decreased the raised parameters (triglyceride, total cholesterol and LDL-cholesterol) to normal values. But the extract has significantly increased HDL-cholesterol, ALT and AST levels. For the aqueous:methanol (70:30) extract given animals, the average serum level of total cholesterol was 60.00±1.30 mg/dL, LDL-cholesterol was 92.80±2.29 mg/dL, HDL-cholesterol was 31.80±1.0 mg/dL and triglyceride was 15.40±0.75 mg/dL while the average serum levels of ALT and AST were 45.60±3.08 and 27.20±1.36 IU/dL, respectively. It is concluded from the study that aqueous:methanolic (70:30) extract of Dodonaea viscosa leaves exerts antihy- perlipidemic and hepatoprotective effects in the alloxan-induced diabetic rabbits

Genotoxic and cytotoxic potential of whole plant extracts of Kalanchoe laciniata by Ames and MTT assay

Lack of data on safety of herbal medicines have endangered human health and life. The present study evaluated the genotoxic and mutagenic effect of Kalanchoe laciniata to access the safety and usefulness of the medicinal plant. Aqua-methanolic and n-hexane extracts of K. laciniata were evaluated for the genotoxic potential using Ames assay and cytotoxicity was evaluated using MTT assay. Ames assay was conducted using two strains of Salmonella typhimurium TA-100 and TA-102 whereas MTT assay was performed on baby hamster kidney cell line BHK-21. Aqua-methanolic extract of K. laciniata exhibited significant mutagenicity when exposed to TA- 102 strain with a mutagenic index of 50.66 and 54.74 at maximum dose 150 mg/plate. The extract was also muta- genic to TA-100 strain but to a lesser extent. M.I of n-hexane extract was 12.15 and 15.51 for TA-100 and TA- 102 respectively. n-hexane extract was mutagenic but little difference was observed between results of two strains. Both extracts were found to be cytotoxic with an IC50 of 321.9 and 638.5 µg/mL for aqua-methanolic and n-hexane extracts respectively. On the basis of results it was concluded that aqua-methanolic and n-hexane extracts of K. mutagenic and cytotoxic potential. It is suggested to explore the plant further to evaluate its safety in rodents and other species