Seamless key agreement framework for mobile-sink in IoT based cloud-centric secured public safety sensor networks

Recently, the Internet of Things (IoT) has emerged as a significant advancement for Internet and mobile networks with various public safety network applications. An important use of IoT-based solutions is its application in post-disaster management, where the traditional telecommunication systems may be either completely or partially damaged. Since enabling technologies have restricted authentication privileges for mobile users, in this paper, a strategy of mobile-sink is introduced for the extension of user authentication over cloud-based environments. A seamless secure authentication and key agreement (S-SAKA) approach using bilinear pairing and elliptic-curve cryptosystems is presented. It is shown that the proposed S-SAKA approach satisfies the security properties, and as well as being resilient to nodecapture attacks, it also resists significant numbers of other well-known potential attacks related with data confidentiality, mutual authentication, session-key agreement, user anonymity, password guessing, and key impersonation. Moreover, the proposed approach can provide a seamless connectivity through authentication over wireless sensor networks to alleviate the computation and communication cost constraints in the system. In addition, using Burrows–Abadi–Needham logic, it is demonstrated that the proposed S-SAKA framework offers proper mutual authentication and session key agreement between the mobile-sink and the base statio

3D analytical modelling and iterative solution for high performance computing clusters

Mobile Cloud Computing enables the migration of services to the edge of the Internet. Therefore, high-performance computing clusters are widely deployed to improve computational capabilities of such environments. However, they are prone to failures and need analytical models to predict their behaviour in order to deliver desired quality-of-service and quality-of-experience to mobile users. This paper proposes a 3D analytical model and a problem-solving approach for sustainability evaluation of high-performance computing clusters. The proposed solution uses an iterative approach to obtain performance measurements to overcome the state space explosion problem. The availability modelling and evaluation of master and computing nodes are performed using a multi-repairman approach. The optimum number of repairmen is also obtained to get realistic results and reduce the overall cost. The proposed model is validated using discrete event simulation. The analytical approach is much faster and in good agreement with the simulations. The analysis focuses on mean queue length, throughput, and mean response time outputs. The maximum differences between analytical and simulation results in the considered scenarios of up to a billion states are less than1.149%,3.82%, and3.76%respectively. These differences are well within the5%of confidence interval of the simulation and the proposed model

An analytical approach for performance analysis of handoffs in the next generation integrated cellular networks and WLANs

The main feature of the next generation wireless communication systems is the ability to establish ubiquitous and seamless access to various radio access technologies (RATs) and standards. For this reason the integration of cellular and wireless local area networks (WLANs) and performance evaluation of the interaction between these technologies is now an important research area. Modelling such systems for performance evaluation is essential to improve the architecture according to the quality ofbservice (QoS) requirements and performance characteristics. In this paper, an analytical model for performance evaluation of an integrated cellular network and a WLAN is considered. WLAN is deployed inside of the cellular network to support handoffs between cellular networks with higher bandwidth. Such an integrated system can be modelled as a two stage open network. An analytical model is proposed together with an exact solution technique in order to evaluate the performance of an integrated system consisting of a cellular network and a WLAN. A two stage queuing system is considered for this purpose. Numerical results are presented for mean queue length values of cellular system as well as the WLAN

Antología literaria 4 : relatos amazónicos

Las lecturas que se muestran en el texto ayudarán a los estudiantes a conocer mejor su cultura y la historia de su pueblo, a mejorar sus capacidades de expresión oral y escrita en la lengua castellana, a valorar a su familia, a respetar a la naturaleza y a cuidar el medio ambiente en el que viven. Les ayudará también a convivir en armonía con las demás personas con las que se relacionan en su casa, en la escuela y en la comunidad

Aruskipawinaka 2 - secundaria : cuaderno de trabajo - Comunicación 2° - Aimara

Los cuadernos de trabajo de Comunicación elaborados para el nivel secundaria tienen el propósito de desarrollar las competencias comunicativas en la lengua originaria, fortalecer la identidad con su lengua y pueblo, además ampliar sus conocimientos a otros pueblos desde una postura crítica y reflexiva de los estudiantes de los pueblos originarios

Stem cells of ependymoma

Ependymomas are tumours that arise throughout the central nervous system. Little is known regarding the aberrant cellular and molecular processes that generate these tumours. This lack of knowledge has hampered efforts to reduce the significant mortality and morbidity that are associated with ependymoma. Here, we review recent data that suggest that radial glia are cells of origin of ependymoma, and discuss the processes that might transform these neural progenitors into ependymoma cancer stem cells

Performability modelling of handoff in wireless cellular networks and the exact solution of system models with service rates dependent on numbers of originating and handoff calls.

Mobility is one of the major issues in the performance characterization of wireless communication systems. Various approaches exist in the literature for performance evaluation of mobile systems, especially the handoff phenomenon. However, since the probability of an ongoing call being dropped due to a handoff failure and the probability of a new call being blocked due to the temporary unavailability of an idle channel are main metrics that affect the performance of wireless cellular systems, it is essential to consider these systems for performability evaluation. In this paper, wireless cellular networks with failures and recovery are modelled. The service rates provided in each operative state are dependent on the number of originating calls as well as handoff calls coming from the neighbouring cells. The spectral expansion solution method together with an approach to handle the job dependent service rates is used. The numerical results are presented comparatively to validate the approximate approach presented previously

Performability modelling of a Kerberos server with frequent key renewal under pseudo-secure conditions for increased security

This paper presents a modelling approach for performability evaluation of Kerberos servers which dynamically renew keys under pseudo-secure conditions in order to significantly reduce the chances of potential intruders. Since the proposed approach involves temporary interruption to link/server access, it has implications in terms of performance degradation. An analytical method is used to evaluate the cost in terms of the degradation of system performance. Unlike previous studies, the failures of the servers are considered together with link/server interruptions for renewals. Therefore the model presented considers the system for exact performability evaluation. Numerical results are provided in order to analyse the effects of renewal times, times between renewals and failures ofthe server

Enhancing the modelling of vertical handover in integrated cellular/WLAN environments

This paper presents a new analytical model to enhance the modelling of vertical handover for integrated cellular/ WLAN systems. The WLAN system considered is within the coverage area of cellular network, hence users can have a downward vertical handover to the WLAN and/or an upward vertical handover to the cellular network. Recent work on the modelling of these systems using a two-stage model with feedback face with some complications in terms of handling certain streams. The possibility of having continuous streams which keep on switching between WLAN and cellular systems, may reduce the practicality of the models. The new analytical model presented in this paper provides restriction on certain flows, to make sure that the handover calls from WLAN to cellular system are not allowed back to the WLAN. Previously proposed analytical models, which do not nullify these streams may not reflect real systems and the results obtained may not be practically applicable especially for such a configuration of cellular/WLAN interaction. A new model is presented with an extra random variable in order to provide that Markovian property is not violated. Results are presented to show that the new model is a significant improvement but more work is needed to analyse more complex scenarios

Critical review of analytical modelling approaches for performability evaluation of the handover phenomena in mobile communication systems

Performability modelling and evaluation of wireless and mobile systems have been of interest for recent research work. Especially, because of the complexity of the next generation wireless and mobile systems, modelling and performance evaluation is essential to improve the architecture according to the quality of service (QoS) requirements and performance characteristics. A considerable amount of the existing work in literature focuses on handover phenomena using analytical modelling and/or simulation of mobile communication systems. This paper presents a perform ability evaluation framework of mobile communication systems with different handover strategies using analytical modelling approaches. The availability and mobility issues are also considered in the proposed models. Well-known approximate Markov reward model solution and the exact Spectral expansion solution approaches are considered. Perform ability measures of proposed models, such as blocking probability and mean queue length are presented