Dynamic multimedia content access in a ubiquitous and distributed computing environment

Ubiquitous computing is the concept of embedding many heterogeneous devices within our everyday environment in such a way that they operate seamlessly and become transparent to the person using them. It covers a wide range of applications and services, but of particular interest is multimedia resource adaptation which involves customization and dynamic adaptation of resources according to usage environments and user preferences; this aims to provide consumers with transparent access. This thesis proposes a content negotiation architecture for dynamic adaptation of multimedia content according to usage environment attributes. The architecture shields users from complex configuration details related to the adaptation of multimedia content, while guiding them through user related choices. The architecture also dynamically updates the multimedia content during transmission and consumption when related usage environment attributes are changed. The content negotiation mechanism in the proposed architecture is then extended and deployed in a mobile computing environment to accommodate transfer of multimedia content application session state between devices in a seamless manner. An application session transfer architecture which allows sessions to be directed, stored and transferred through an intermediary session server is proposed. The thesis also considers the foregoing work on the adaptation of multimedia resources applied to sharing in a Peer-to-Peer (P2P) network. It proposes a super peer based dynamic resource adaptation architecture which employs \u27pull\u27 and \u27push\u27 two-stage adaptation approach. This guides users through resource search and configuration details without exposing them to unnecessary technical details; the result is that requested content is transparently adapted to heterogeneous terminal devices. Two separate, but related, modifications are proposed to further improve the performance of the proposed P2P architecture. Firstly, peers are clustered according to registered geographic location information and secondly, based on that registered location information, a locality-based service is introduced which allows users to search services according to their geographic locations. The latter encourages service providers to increase the uptime of their devices and hence provide spare computing power for active adaptation of resources for low-end peers. Resource replication is an important aspect of a P2P system and an adaptive resource replication strategy based on the proposed P2P architecture is presented. It uses resource request rate as the metric to trigger the resource replication process, and proportionally replicates multimedia resources into various configuration states according to the properties of peers and the size of peer clusters. Also, the strategy uses peer related information stored on super peers to determine which peers should be selected to perform adaptive replications and where the resulting replicas should be stored. The proposed adaptive replication strategy demonstrates that the network delays are reduced while resource hit rate is increased in comparison to other replication strategies. Investigation of the deployment of a BitTorrent (BT) - like approach in the proposed P2P resource adaptation architecture is also considered in this thesis. In addition, the architecture\u27s peer selection strategy is adopted and evaluated as a way to enhance the peer selection process in BT. The strategy uses super peers as trackers to intelligently select peers according to their capabilities and shared resource segments and overcome the scalability issue of existing BT implementation. The proposed selection strategy reduces average access time and increases download speed when compared with the existing BT peer selection process with randomly selected peers. Also, the deployment of BT in the proposed P2P architecture shows that it greatly reduces the congested download problem which was previously reported

Subarea law of entanglement in nodal fermionic systems

We investigate the subarea law scaling properties of the block entropy in bipartite fermionic systems which do not have a finite Fermi surface. It is found that in gapped regimes the leading subarea term is a negative constant, whereas in critical regimes with point nodes the leading subarea law is a logarithmic additive term. At the phase boundary that separates the critical and non-critical regimes, the subarea scaling shows power-law behavior.Comment: 4 pages,4 figures; published versio

Scaling Behavior of Entanglement in Two- and Three-Dimensional Free Fermions

Exactly solving a spinless fermionic system in two and three dimensions, we investigate the scaling behavior of the block entropy in critical and non-critical phases. The scaling of the block entropy crucially depends on the nature of the excitation spectrum of the system and on the topology of the Fermi surface. Noticeably, in the critical phases the scaling violates the area law and acquires a logarithmic correction \emph{only} when a well defined Fermi surface exists in the system. When the area law is violated, we accurately verify a conjecture for the prefactor of the logarithmic correction, proposed by D. Gioev and I. Klich [quant-ph/0504151].Comment: 4 pages, 4 figure

Mobility management in B3G networks: a middleware-based approach

International audienceThe B3G (Beyond 3G) networking will enable mobile users to roam freely through heterogeneous networks on an all-IP platform. However, mobility handling in such an environment poses new challenges. Traditionally, mobility protocols such as Mobile IP, SIP and SCTP are used to manage mobility in B3G, but they require telecommunication companies to either modify existing network infrastructures or deploy central entities in the network core to handle mobility. This is not feasible in a fully distributed computing environment (e.g., P2P) and mobile ad hoc networks that are part of B3G networking. As an alternative, this paper introduces a middleware component with modularized functionalities to facilitate mobility management in a fully distributed B3G environment

Coordinated in-band ad-hoc transmission underlying cellular networks

International audienceIn this article ad-hoc communications underlying cellular networks is studied. Two branches of usage cases, which lead to two modes of operation, are analyzed. We propose a coordinated in-band scheme where the ad-hoc communication uses the same licensed band operating the cellular networks andis under the control of cellular network operators. We show that the interference resulting from in-band ad-hoc transmission can be effectively managed by proper scheduling. The spectral efficiency gain is substantially increased using the proposed scheme

Capacity and energy efficiency of picocell deployment in LTE-A networks

International audienceIn this paper, we show the impact of deploying picocells on the capacity and energy efficiency of LTE-A networks. We analyze the Erlang-like capacity of a network composed of macro networks only and study the impact of introducing a number of picocells per site. Knowing that the capacity is not the only factor that will drive the evolution of the network, we also consider the energy efficiency as a Key Performance Indicator (KPI). Our results show that, in some scenarios, introducing picocells is a good network densification method as they achieve a higher network capacity with good energy efficienc

Verbascoside attenuates experimental varicocele-induced damage to testes and sperm levels through up-regulation of the hypothalamus-pituitary-gonadal (HPG) axis

Context Verbascoside (VB), which is found in many medicinal plant families, exhibits biological activities in various diseases. However, its effects on varicocele (VCL)-induced damage remain unknown. Objective To investigate the effects and mechanism of VB on experimental rats with varicocele (VCL)-induced damage. Materials and methods Sixty sexually mature male Sprague-Dawley (SD) rats were divided into six groups (n = 10): control, control-sham, VCL-vehicle (normal saline), and VCL + VB groups (50, 100, and 200 mg/kg/day, intraperitoneally). After 4 weeks of VB treatment, all animals were sacrificed, and the body and testicular weight, sperm quality parameters, histopathology, antioxidant status, and hormone levels were tested. The levels of gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone in the hypothalamus were detected by western blot. Results Compared with the VCL-vehicle group (41.14%), administration of VB significantly increased the sperm viability (59.29, 65.45, 84.93%). VB groups showed higher Johnson’s score (3.57 ± 0.15, 4.71 ± 0.26, 7.93 ± 0.37) than VCL-vehicle group (2.72 ± 0.24). Antioxidant status and hormone levels alterations were also observed. Meanwhile, the mean number of apoptotic tubules (8.15 ± 0.96, 6.61 ± 1.05, 2.17 ± 0.08) and apoptotic index showed a marked decrease. Compared with the VCL-vehicle group (0.21 ± 0.09), the VB groups (0.36 ± 0.07, 0.42 ± 0.06, 0.88 ± 0.10) showed considerable increases in GnRH. Discussion and conclusions VB has protective effects on reproductive organs and VB may be therapeutically useful in the treatment of varicocele through up-regulation of the HPG axis

Ecological Risks Arising in the Regional Water Resources in Inner Mongolia Due to a Large-Scale Afforestation Project

In recent years, a large-scale afforestation campaign has been implemented in Inner Mongolia, China, to control desertification and soil erosion. However, the water consumption associated with large-scale afforestation significantly impacts the water resources in Inner Mongolia, resulting in a major ecological risk. This study aimed to evaluate the ecological risk of water resources caused by afforestation in the region. In this study, using land cover data, normalized difference vegetation index (NDVI) data, and meteorological data, we performed trend analysis and used the water balance equation and water security index (WSI) to analyze the ecological risks of water resources caused by afforestation in Inner Mongolia from 2000 to 2020. The results show that (1) the afforestation area in Inner Mongolia was 5.37 × 104 km2 in 2000–2020; (2) afforestation in arid and semi-arid areas led to a reduction in water resources; (3) afforestation reduced water resources in the study area by 62 million cubic meters (MCM) per year; and (4) ~76% of afforestation regions faced ecological risks related to water resources. This study provides scientific suggestions for the sustainable development of regional water resources and afforestation