IDENTIFYING MAVENS IN SOCIAL NETWORKS

This thesis studies social influence from the perspective of users\u27 characteristics. The importance of users\u27 characteristics in word-of-mouth applications has been emphasized in economics and marketing fields. We model a category of users called mavens where their unique characteristics nominate them to be the preferable seeds in viral marketing applications. In addition, we develop some methods to learn their characteristics based on a real dataset. We also illustrate the ways to maximize information flow through mavens in social networks. Our experiments show that our model can successfully detect mavens as well as fulfill significant roles in maximizing the information flow in a social network where mavens considerably outperform general influential users for influence maximization. The results verify the compatibility of our model with real marketing applications

Structural Health Monitoring System Trade Space Analysis Tool with Consideration for Crack Growth, Sensor Degradation and a Variable Detection Threshold

Structural Health Monitoring (SHM) systems face many obstacles and gaps that have resulted in the slow implementation in real-world applications. These obstacles include technology performance, implementation issues and a solid business case that justifies the investment in a SHM system. The presentation of a solid business case for the SHM system is a great challenge and arguably is the main factor contributing to the slow implementation of this technology. The research intent of this dissertation is to focus on the business case by providing a tool to aid decision makers. Simulated aging aircraft flight data are used in this effort due to the fact that many aging military aircraft will be flying beyond their initially intended design life. An analytical model was developed to address the business case and the integration of the SHM system into Condition Based Maintenance (CBM). The model aids the calculation of the cost of Life Cycle (LC) events resulting from the implementation of the SHM system on an aging aircraft. In addition, the model captures the events and effect on aircraft availability due to different SHM detection threshold settings and replacement of degraded sensors. The model captures false alarm rates, crack growth, probability of detection, and sensor degradation amongst other parameters. The proposed analytical model is a useful tool that provides the decision makers the confidence to either implement the SHM system on an aging military aircraft or not. Two models were developed; one was the SHM system model with no degradation and the second was the SHM system model with simulated degrading sensors. Three major subcomponents of the SHM model will be the sensor detection component, the crack growth component and the sensor degradation component (second model only)

Effects of Temperature and Shot-peening Intensity on Fretting Fatigue Behavior of Titanium Alloy Ti-6Al-4A

Effects of temperature and shot-peening intensity on fretting fatigue behavior of Ti-6Al-4A were investigated in this study. S-N curves were obtained for both room and elevated temperatures (260 C) for two different shot-peened intensities (4A and 10A). Stress relaxation behavior under both fretting fatigue at elevated temperature and temperature exposure only were also investigated after their measurements were calculated using X-ray diffraction method. The crack initiation location and the crack angle orientation along the surface were determined using optical and scanning electron microscopy (SEM). Cracks initiated near the trailing edge of the tested specimens. Cracks initiated on the contact surface for both specimens with 4A and 10A shot-peened intensities at elevated temperature. Finite element analysis was performed by commercially available software, ABAQUS, to obtain contact region state variables such as stress, strain and displacement. Those state variables were needed for the computation of fretting fatigue parameters. Fatigue parameters, such as stress range, effective stress and modified shear stress range (MSSR), were analyzed. It was found that there was relaxation of residual compressive stress during fretting fatigue at room and elevated temperature, greater stress relaxation occurred when higher temperature was applied. Also, both 4A and 10A specimens had the same percentage of residual stress relaxation due to temperature exposure only. Further, elevated temperature conditions negate the effect of shot-peening, thereby providing no improvement in fatigue life. On the other hand shot-peening at room temperature conditions improved fatigue life due to shot-peening. Both shot-peening intensities at room temperature provided an improvement to fatigue life with the 10A providing the greatest extension to fatigue life. Also, the (MSSR) pa

A Comparative Analysis of Risk Culture in Financial and Non-Financial Firms

The following study explores risk culture by incorporating viewpoints from publications that cover: risk management, leadership, communication, employee motivation and satisfaction, and learning organisations. The aspiration of the study is to determine whether a distinction between risk culture in financial and non-financial industries in Bahrain exists, and clarify the possible reasoning behind any detected variation. Together with identifying any apparent weak or strong risk culture due to the general culture in the Middle East. The contribution of the study is to provide a tool to assess risk culture between and within, financial and nonfinancial institutions. Additionally, the paper brings to light the lack of risk-awareness in the middle east due to poor perceptions towards the concept of risk culture. At present, papers depict risk culture as a relatively new concept in the financial industry, compared to the non-financial industry. Forming the assumption that firms operating in the non-financial industry have a generally ‘stronger’ risk culture than financial industry firms. As such, academic and practice literature state that financial firms can benefit from incorporating non-financial firms risk culture behaviours. Risk culture is assumed to be a holistic notion. The study follows a qualitative approach, yet benefits from some quantitative tools for interpretation. Accordingly, the ‘strength’ of an organisations risk culture is investigated via a five point Likert Scale questionnaire distributed to employees in Bahrain’s financial and non-financial industries. The study finds that financial and non-financial institutions in Bahrain require similar developments to foster a risk-aware culture. Both industries leave the vaster regional and societal culture to influence employees perceptions. Bahrain’s institutions need to reconsider their risk management tools and models, promote a learning culture, and place great efforts to deviate themselves from the Middle Eastern misconceived notion that culture cannot be cultivated to support organisational goals

Integrated Centralized Substation Protection

Substation cyber assets are mission critical for protection and control of substations. Managing and ensuring their secure operation is of paramount importance. A known vulnerability is hidden failures which are responsible for about 10% of mis-operations and their detrimental effects on system reliability. The paper presents an integrated centralized substation protection approach that is based on the recently developed setting-less relays which are integrated into a centralized substation protection scheme with the following features: (a) fast, dependable and secure protection of each substation protection zone by a settingless relay, (b) supervision of each settingless relay by validating relay input data by a substation wide state estimator, (c) self-healing against hidden failures by detecting and identifying compromised data and replacing them with estimated values, thus ensuring that the settingless relays will always operate on validated data. The paper provides a summary review of the settingless protective relay and introduces the Integrated Centralized Substation Protection Scheme (ICSP) which uses the data from all settingless relays in the substation to perform a substation wide state estimation. The state estimator uses a hypothesis testing algorithm to determine whether (a) data are valid with no faults or hidden failures, (b) data are valid and a fault exists in the system, or (c) some data are invalid due to hidden failures. In the last case, the state estimator uses the substation state and model to replace the compromised data with estimated values and thus enabling self-immunization against hidden failures. A byproduct of the method is the substation state estimate which is transmitted to the control center where it is used with the state from all substations to synthesize the system wide state estimate and model. Architectural issues are addressed as well as migration issues of existing systems into the proposed ICSP

On-demand offloading collaboration framework based on LTE network virtualisation

Recently, there has been a significant increase in data traffic on mobile networks, due to the growth in the numbers of users and the average data volume per user. In a context of traffic surge and reduced revenues, operators face the challenge of finding costless solutions to increase capacity and coverage. Such a solution should necessarily rule out any physical expansion, and mainly conceive real-time strategies to utilise the spectrum more efficiently, such as network offload and Long-term Evolution (LTE) network virtualisation. Virtualisation is playing a significant role in shaping the way of networking now and in future, since it is being devised as one of the available technologies heading towards the upcoming 5G mobile broadband. Now, the successful utilisation of such innovative techniques relies critically on an efficient call admission control (CAC) algorithm. In this work, framework is proposed to manage the operation of a system in which CAC, virtualisation and Local break out (LBO) strategies are collaboratively implemented to avoid congestion in a mobile network, while simultaneously guaranteeing that measures of quality of service (QoS) are kept above desired thresholds. In order to evaluate the proposed framework, two simulation stages were carried out. In the first stage, MATLAB was used to run a numerical example, with the purpose of verifying the mathematical model of the proposed framework in air interface level. The second stage involved of using open source applications such as, Emulated Virtual Environment (EVE) and Wireshark, for emulating the traffic in the network for different scenarios inside the core network. The results confirm the effectiveness of the proposed framework

A perspective on magnetic core–shell carriers for responsive and targeted drug delivery systems

Magnetic core–shell nanocarriers have been attracting growing interest owing to their physicochemical and structural properties. The main principles of magnetic nanoparticles (MNPs) are localized treatment and stability under the effect of external magnetic fields. Furthermore, these MNPs can be coated or functionalized to gain a responsive property to a specific trigger, such as pH, heat, or even enzymes. Current investigations have been focused on the employment of this concept in cancer therapies. The evaluation of magnetic core–shell materials includes their magnetization properties, toxicity, and efficacy in drug uptake and release. This review discusses some categories of magnetic core–shell drug carriers based on Fe2O3 and Fe3O4 as the core, and different shells such as poly(lactic-co-glycolic acid), poly(vinylpyrrolidone), chitosan, silica, calcium silicate, metal, and lipids. In addition, the review addresses their recent potential applications for cancer treatment.The authors would like to acknowledge Qatar University for funding the project: GCC Co-Fund Program Grant #GCC-2017-001 and student grant QUST-1-CAS-2019-36. The publication of this article was funded by the Qatar National Library.Scopu

The prevalence of metabolic syndrome components, individually and in combination, in male patients admitted with acute coronary syndrome, without previous diagnosis of diabetes mellitus

Background: Mortality from cardiovascular disease in the Middle East is projected to increase substantially in the coming decades. The prevalence of metabolic syndrome (MS) in acute coronary syndrome (ACS) continues to raise interest, but data from the Middle East is limited, especially in non-diabetic patients. This study was conducted to ascertain the prevalence of MS and frequency of its components, individually and in combination, in a male population presenting with ACS, but without a previous diagnosis of diabetes mellitus (DM).Methods: This is a prospective study of 467 consecutive male patients hospitalized for ACS. They were categorized according to the specific criteria stated in the latest joint statement for the global definition of MS.Results: The mean age was (49.7910.7 years). Of the 467 patients, 324 (69.4%) fulfilled the criteria for MS. ST-Elevation Myocardial Infarction (STEMI) was identified in 178 patients (54.9%), and non-ST elevation ACS (NSTE-ACS) in 146 patients (45.1%). These proportions were not significantly different from those without MS (STEMI 51.7% vs. NSTE-ACS 48.3%, respectively). However, patients with MS were older (50.6910 vs. 47.9911 years; p0.012), and more than half of those with MS were above 50 years. The most common abnormal metabolic components were reduced high-density lipoprotein cholesterol (HDL-c; 94.1%), elevated fasting blood glucose (FBG; 89.8%), and elevated triglycerides (81.8%), followed by increased waist circumference (61.7%) and raised blood pressure (40.4%). The majority of patients with MS had three or more metabolic components (326 patients, 69.4%), and 102 (21.8%) had two components, but only 37 (8.4%) had a single component.Conclusions: In ACS patients, without previous history of DM, MS is highly prevalent. Reduced HDL, elevated FBG and triglycerides were the most frequent metabolic components. The majority had multiple components. These findings raise alarm and show that drug therapy alone may not be fully effective, unless the underlying risk factors causing MS, such as weight and exercise, are also tackled.Keywords: male; metabolic syndrome; acute coronary syndrome; diabetes mellitu