An intelligent radio access network selection and optimisation system in heterogeneous communication environments

PhDThe overlapping of the different wireless network technologies creates heterogeneous communication environments. Future mobile communication system considers the technological and operational services of heterogeneous communication environments. Based on its packet switched core, the access to future mobile communication system will not be restricted to the mobile cellular networks but may be via other wireless or even wired technologies. Such universal access can enable service convergence, joint resource management, and adaptive quality of service. However, in order to realise the universal access, there are still many pending challenges to solve. One of them is the selection of the most appropriate radio access network. Previous work on the network selection has concentrated on serving the requesting user, but the existing users and the consumption of the network resources were not the main focus. Such network selection decision might only be able to benefit a limited number of users while the satisfaction levels of some users are compromised, and the network resources might be consumed in an ineffective way. Solutions are needed to handle the radio access network selection in a manner that both of the satisfaction levels of all users and the network resource consumption are considered. This thesis proposes an intelligent radio access network selection and optimisation system. The work in this thesis includes the proposal of an architecture for the radio access network selection and optimisation system and the creation of novel adaptive algorithms that are employed by the network selection system. The proposed algorithms solve the limitations of previous work and adaptively optimise network resource consumption and implement different policies to cope with different scenarios, network conditions, and aims of operators. Furthermore, this thesis also presents novel network resource availability evaluation models. The proposed models study the physical principles of the considered radio access network and avoid employing assumptions which are too stringent abstractions of real network scenarios. They enable the implementation of call level simulations for the comparison and evaluation of the performance of the network selection and optimisation algorithms

Diseño e implementación de una estrategia de comunicación en redes sociales chinas de la actividad de grupos de investigación españoles

[ES] Desde hace unas décadas, es natural que los investigadores colaboren con investigadores de otros países. Esto es incluso fomentado por los proyectos europeos de programas como H2020 o Eramus +. En la carrera de un investigador es siempre positivo hacer visitas a otros países e instituciones y colaborar con otros investigadores, aprendiendo nuevas técnicas y explorando nuevos temas. El empuje que ha supuesto el uso de herramientas de comunicación online, ha facilitado mucho que estas colaboraciones perduren en el tiempo y que las estancias iniciales de contacto puedan ser más cortas. No obstante, establecer los primeros contactos entre grupos no es siempre fácil. En este trabajo se aborda este problema. El objetivo principal consiste en diseñar e implementar una campaña de comunicación de la investigación de grupos de la UPV en redes sociales chinas, de manera que se pueda depertar el interés de investigadores chinos en colaborar y realizar estancias de investigación en grupos españoles. Las conclusiones del mismo se utilizarán para documentar y explicar estas estrategias a grupos investigadores españoles como difundir su actividad en China.[EN] In the last decades, it has been natural for researchers to collaborate with researchers from other countries. This is even encouraged by the European projects of programs like H2020 or Eramus +. In a researcher's career, it is always positive to visit other countries and institutions and collaborate with other researchers, learning new techniques and exploring new topics. The push brought about by the use of online communication tools has made it much easier for these collaborations to last over time and for the initial contact stays to be shorter. However, establishing the first contacts between groups is not always easy. This problem is addressed in this work. The main objective is to design and implement a communication campaign of UPV research groups on Chinese social networks so that Chinese researchers' interest in collaborating and carrying out research stays in Spanish groups can be awakened. The conclusions will be used to document and explain these strategies to Spanish research groups to disseminate their activity in China.Luo, W. (2021). Diseño e implementación de una estrategia de comunicación en redes sociales chinas de la actividad de grupos de investigación españoles. Universitat Politècnica de València. http://hdl.handle.net/10251/175114TFG

Design and evaluation of advanced collusion attacks on collaborative intrusion detection networks in practice

Joint 15th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, 10th IEEE International Conference on Big Data Science and Engineering and 14th IEEE International Symposium on Parallel and Distributed Processing with Applications, IEEE TrustCom/BigDataSE/ISPA 2016, Tianjin, China, 23-26 August 2016To encourage collaboration among single intrusion detection systems (IDSs), collaborative intrusion detection networks (CIDNs) have been developed that enable different IDS nodes to communicate information with each other. This distributed network infrastructure aims to improve the detection performance of a single IDS, but may suffer from various insider attacks like collusion attacks, where several malicious nodes can collaborate to perform adversary actions. To defend against insider threats, challenge-based trust mechanisms have been proposed in the literature and proven to be robust against collusion attacks. However, we identify that such mechanisms depend heavily on an assumption of malicious nodes, which is not likely to be realistic and may lead to a weak threat model in practical scenarios. In this paper, we analyze the robustness of challenge-based CIDNs in real-world applications and present an advanced collusion attack, called random poisoning attack, which derives from the existing attacks. In the evaluation, we investigate the attack performance in both simulated and real CIDN environments. Experimental results demonstrate that our attack can enables a malicious node to send untruthful information without decreasing its trust value at large. Our research attempts to stimulate more research in designing more robust CIDN framework in practice.Department of Computing2016-2017 > Academic research: refereed > Refereed conference paperbcw

Generalized bioinspired approach to a daytime radiative cooling "skin"

Energy-saving cooling materials with strong operability are desirable towards sustainable thermal management. Inspired by the cooperative thermo-optical effect in fur of polar bear, we develop a flexible and reusable cooling skin via laminating a polydimethylsiloxane film with a highly-scattering polyethylene aerogel. Owing to its high porosity of 97.9% and tailored pore size of 3.8 +- 1.4 micrometers, superior solar reflectance of 0.96 and high transparency to irradiated thermal energy of 0.8 can be achieved at a thickness of 2.7 mm. Combined with low thermal conductivity of 0.032 W/m/K of the aerogel, the cooling skin exerts midday sub-ambient temperature drops of 5-6 degrees in a metropolitan environment, with an estimated limit of 14 degrees under ideal service conditions. We envision that this generalized bilayer approach will construct a bridge from night-time to daytime radiative cooling and pave the way for economical, scalable, flexible and reusable cooling materials.Comment: 15 pages, 4 figures, of which another version has been accepted by ACS ami but not published ye

Secure Information Transmissions in Wireless-powered Cognitive Radio Networks for Internet of Medical Things

In this paper, we consider the issue of the secure transmissions for the cognitive radio-based Internet of Medical Things (IoMT) with wireless energy harvesting. In these systems, a primary transmitter (PT) will transmit its sensitive medical information to a primary receiver (PR) by a multi-antenna-based secondary transmitter (ST), where we consider that a potential eavesdropper may listen the PT's sensitive information. In the meanwhile, the ST also transmits its own information concurrently by utilizing spectrum sharing. We aim to propose a novel scheme for jointly designing the optimal parameters, i.e., energy harvesting (EH) time ratio and secure beamforming vectors, for maximizing the primary secrecy transmission rate while guaranteeing secondary transmission requirement. For solving the non-convex optimization problem, we transfer the problem into convex optimization form by adopting the semi-definite relaxation (SDR) method and Charnes-Cooper transformation technique. Then, the optimal secure beamforming vectors and energy harvesting duration can be obtain easily by utilizing the CVX tools. According to the simulation results of secrecy transmission rate, i.e., secrecy capacity, we can observe that the proposed protocol for the considered system model can effectively promote the primary secrecy transmission rate when compared with traditional zero-forcing (ZF) scheme, while ensuring the transmission rate of the secondary system

Histopathological Features and Composition of Gut Microbiota in Rhesus Monkey of Alcoholic Liver Disease

Alcohol-induced chronic liver disease (ALD) is becoming the most common liver disease in the world. However, there are no effective, universally accepted therapies for ALD. The etiology of ALD remains blurry so far. Historical evidence has demonstrated a link between the liver and gut microbiota. But it is difficult to distinguish the effect of gut microbiota changes caused by alcohol consumption in humans since the microbiota change detected in humans is complicated by diet and environmental factors. Due to the genetic, physiological, metabolic, and behavioral similarities to humans, the rhesus monkey provides excellent translational validity in preclinical studies, and the diet and environmental conditions can be controlled well in rhesus monkey. In our study, we explored the relationship between ALD and the gut microbiome in the rhesus monkeys with alcoholic liver steatosis. Our results showed that there was a change of the bacterial community structure in monkeys with ALD. Differences of the relative abundances of gut microbiota at phylum, order, family, genus, and species levels were observed between control monkeys and monkeys with ALD, and different pathways enriched in the monkeys with ALD were identified by metagenomic function analysis. Firmicutes, Proteobacteria, Verrucomicrobia tended to increase whereas Bacteroidetes and Actinobacteria decreased in the fecal microbiota of ALD group compared to the control group. Lactobacillales and Lactobacillus significantly decreased in ALD monkeys compared with normal monkeys, Streptococcus was lower in the ALD group compared with the control group. The non-human primate model of ALD will be useful for exploration of the microbiome markers as diagnosis and potentially prognosis for ALD. The ALD model will benefit the development of new therapeutic procedures for treating ALD and provide safety and efficacy evaluation for clinical application

Modeling Rett Syndrome Using TALEN-Edited MECP2 Mutant Cynomolgus Monkeys

Gene-editing technologies have made it feasible to create nonhuman primate models for human genetic disorders. Here, we report detailed genotypes and phenotypes of TALEN-edited MECP2 mutant cynomolgus monkeys serving as a model for a neurodevelopmental disorder, Rett syndrome (RTT), which is caused by loss-of-function mutations in the human MECP2 gene. Male mutant monkeys were embryonic lethal, reiterating that RTT is a disease of females. Through a battery of behavioral analyses, including primate-unique eye-tracking tests, in combination with brain imaging via MRI, we found a series of physiological, behavioral, and structural abnormalities resembling clinical manifestations of RTT. Moreover, blood transcriptome profiling revealed that mutant monkeys resembled RTT patients in immune gene dysregulation. Taken together, the stark similarity in phenotype and/or endophenotype between monkeys and patients suggested that gene-edited RTT founder monkeys would be of value for disease mechanistic studies as well as development of potential therapeutic interventions for RTT

Co-Regulations of Spartina alterniflora Invasion and Exogenous Nitrogen Loading on Soil N2O Efflux in Subtropical Mangrove Mesocosms

We thank Zhonglei Wang, Cunxin Ning, Hui Chen, Qian Huang, Fang Liu and Jian Zhou for their assistance with the greenhouse experiments and gas sampling. We are also grateful to Weimin Song, Rashid Rafique, Junyi Liang, Zheng Shi and Jianyang Xia for editing the manuscript.Both plant invasion and nitrogen (N) enrichment should have significant impact on mangrove ecosystems in coastal regions around the world. However, how N2O efflux in mangrove wetlands responds to these environmental changes has not been well studied. Here, we conducted a mesocosm experiment with native mangrove species Kandelia obovata, invasive salt marsh species Spartina alterniflora, and their mixture in a simulated tide rotation system with or without nitrogen addition. In the treatments without N addition, the N2O effluxes were relatively low and there were no significant variations among the three vegetation types. A pulse loading of exogenous ammonium nitrogen increased N2O effluxes from soils but the stimulatory effect gradually diminished over time, suggesting that frequent measurements are necessary to accurately understand the behavior of N-induced response of N2O emissions. With the N addition, the N2O effluxes from the invasive S. alterniflora were lower than that from native K. obovata mesocosms. This result may be attributed to higher growth of S. alterniflora consuming most of the available nitrogen in soils, and thus inhibiting N2O production. We concluded that N loading significantly increased N2O effluxes, while the invasion of S. alterniflora reduced N2O effluxes response to N loading in this simulated mangrove ecosystem. Thus, both plant invasion and excessive N loading can co-regulate soil N2O emissions from mangrove wetlands, which should be considered when projecting future N2O effluxes from this type of coastal wetland.Yeshttp://www.plosone.org/static/editorial#pee

An open science resource for establishing reliability and reproducibility in functional connectomics

Efforts to identify meaningful functional imaging-based biomarkers are limited by the ability to reliably characterize inter-individual differences in human brain function. Although a growing number of connectomics-based measures are reported to have moderate to high test-retest reliability, the variability in data acquisition, experimental designs, and analytic methods precludes the ability to generalize results. The Consortium for Reliability and Reproducibility (CoRR) is working to address this challenge and establish test-retest reliability as a minimum standard for methods development in functional connectomics. Specifically, CoRR has aggregated 1,629 typical individuals’ resting state fMRI (rfMRI) data (5,093 rfMRI scans) from 18 international sites, and is openly sharing them via the International Data-sharing Neuroimaging Initiative (INDI). To allow researchers to generate various estimates of reliability and reproducibility, a variety of data acquisition procedures and experimental designs are included. Similarly, to enable users to assess the impact of commonly encountered artifacts (for example, motion) on characterizations of inter-individual variation, datasets of varying quality are included

Méthodes d’homogénéisation et modèles d’interface imparfaite élastodynamiques pour des composites

This work, motivated by the recent development of metamaterials, has the double objective of contributing to the elaboration of elastodynamic homogenization methods for periodic composite materials and of contributing to the establishment of imperfect elastodynamic interface models for composite materials. The first part of this thesis is concerned with Willis' theory of elastodynamic homogenization and the two-scale elastodynamic homogenization method. In view of the difficulties in obtaining the effective constitutive laws in Willis' theory, an efficient iterative method is proposed to obtain precise dispersion relations and to build the effective constitutive laws in the cases of low frequency and long wavelength. At the same time, the two-scale homogenization method is developed with the help of an assumption, which allows avoiding the tedious derivation of high-order asymptotic terms and obtaining a general high-order expression of the effective impedance. These results are applied and illustrated in the case of laminated composites.In the second part of the work, imperfect elastodynamic interface models are established by replacing, in a composite, the interphase of thin uniform thickness with an imperfect interface of zero thickness satisfying equivalent jump conditions. These models are in fact an elastodynamic extension of the corresponding imperfect elastostatic ones. Finally, they are numerically implemented and illustrated by using the Finite Difference Time Domain (FDTD) and the Explicit Simplified Interface Method (ESIM)Ce travail de thèse, motivé par le développement récent de métamatériaux, a pour double objectif de contribuer à l’élaboration de méthodes d’homogénéisation élastodynamique pour les matériaux composites périodiques et de contribuer à l’établissement de modèles d’interface imparfaite élastodynamique pour les matériaux composites. La première partie de ce travail de thèse s’intéresse à la théorie d’homogénéisation élastodynamique de Willis et à la méthode d’homogénéisation élastodynamique à deux échelles. Au vu des difficultés liées à l’obtention des lois constitutives effectives dans la théorie de Willis, une méthode itérative efficace est proposée pour obtenir des relations de dispersion précises et pour construire les lois constitutives effectives dans les cas à basse fréquence et à grande longueur d’onde. En même temps, la méthode d’homogénéisation à deux échelles est développée à l’aide d’une hypothèse permettant d'éviter la dérivation fastidieuse de termes asymptotiques d'ordre élevé et d’obtenir une expression générale d'ordre élevé de l'impédance effective. Ces résultats sont appliqués et illustrés dans le cas des composites stratifiés.Dans la deuxième partie du travail, des modèles d’interface élastodynamique imparfaite sont établis en remplaçant, dans un composite, une interphase d’épaisseur uniforme mince par une interface imparfaite d’épaisseur nulle qui satisfont à des conditions de saut équivalentes. Ces modèles sont en fait une extension élastodynamique des modèles d’interface élastostatique imparfaite correspondants. Enfin, ils sont numériquement implantés et illustrés à l'aide du domaine temporel à différence finie (FDTD) et de la méthode d'interface simplifiée explicite (ESIM