Now showing items 1-20 of 1751

    • Asymmetric copolymers: synthesis, properties, and applications of gradient and other partially segregated copolymers

      Zhang, J; Farias-Mancilla, B; Destarac, M; Schubert, US; Keddie, DJ; Guerrero-Sanchez, C; Harrisson, S; MOE Key Laboratory, of Material Physics and Chemistry under Extraordinary Conditions, Shaanxi Key Laboratory of Macromolecular Science and Technology, Department of Applied Chemistry, School of Science, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, P. R. China. (Wiley, 2018-09-16)
      Asymmetric copolymers are a class of materials with intriguing properties. They can be defined by a distribution of monomers within the polymer chain that is neither strictly segregated, as in the case of block copolymers, nor evenly distributed throughout each chain, as in the case of statistical copolymers. This definition includes gradient copolymers as well as block copolymers that contain segments of statistical copolymer. In this review, different methods to synthesize asymmetric copolymers are first discussed. The properties of asymmetric copolymers are investigated in comparison to those of block and random counterparts of similar composition. Finally, some examples of applications of asymmetric copolymers, both academic and industrial, are demonstrated. The aim of this review is to provide a perspective on the design and synthesis of asymmetric copolymers with useful applications.
    • Measuring ZnO nanoparticles available co ncentrations in contaminated soils using the diffusive gradient in thin-films (DGT) technique

      Pouran, Hamid; Alkasbi, Mohammed; Lahive, Elma; Lofts, Stephen; Zhang, Hao (Elsevier, 2021-12-31)
      A major gap in understanding nanomaterials behaviour in the environment is a lack of reliable tools to measure their available concentrations. In this research we use diffusive gradients in thin films (DGT) for measuring concentrations of zinc oxide nanoparticles (ZNO NPs) in soils. Available nanoparticle concentrations were assessed by difference, using paired DGT devices with and without 1000 MWCO dialysis membranes to exclude NPs. We used ZnO because its toxic effects are accelerated through dissolution to Zn2+. Our test soils had different pH and organic matter (OM) contents, which both affect the dissolution rate of ZnO NPs. Woburn (pH≈6.9, OM≈1.8%) and Lufa (pH≈5.9, OM≈4.2%) soils were spiked to a single concentration of 500 mg of ZnO NPs per 1 kg of soil and the available concentrations of ZnO NPs and dissolved zinc were evaluated in 3, 7, 14, 21, 28, 60, 90, 120, 150 and 180 day intervals using DGT. The results showed that the dissolution of ZnO NPs, as well as the available concentrations of both dissolved and nanoparticulate Zn, were much higher in Lufa soil than in Woburn. This work demonstrates that DGT can be used as a simple yet reliable technique for determining concentrations of ZnO NPs in soils and probing its dissolution kinetics.
    • Fog vehicular computing: augmentation of fog computing using vehicular cloud computing

      Sookhak, Mehdi; Yu, F Richard; He, Ying; Talebian, Hamid; Sohrabi Safa, Nader; Zhao, Nan; Khan, Muhammad Khurram; Kumar, Neeraj (IEEE, 2017-07-27)
      Fog computing has emerged as a promising solution for accommodating the surge of mobile traffic and reducing latency, both known to be inherent problems of cloud computing. Fog services, including computation, storage, and networking, are hosted in the vicinity of end users (edge of the network), and, as a result, reliable access is provisioned to delay-sensitive mobile applications. However, in some cases, the fog computing capacity is overwhelmed by the growing number of demands from patrons, particularly during peak hours, and this can subsequently result in acute performance degradation. In this article, we address this problem by proposing a new concept called fog vehicular computing (FVC) to augment the computation and storage power of fog computing. We also design a comprehensive architecture for FVC and present a number of salient applications. The result of implementation clearly shows the effectiveness of the proposed architecture. Finally, some open issues and envisioned directions are discussed for future research in the context of FVC.
    • Information security collaboration formation in organisations

      Sohrabi Safa, Nader; Maple, Carsten; Watson, Tim; Furnell, Steve (Institution of Engineering and Technology (IET), 2018-02-09)
      Collaboration between employees in the domain of information security efficiently mitigates the effect of information security attacks on organisations. Collaboration means working together to do or to fulfil a shared goal, the target of which in this paper is the protection of the information assets in organisations. Information Security Collaboration (ISC) aims to aggregate the employees’ contribution against information security threats. This study clarifies how ISC is to be developed and how it helps to reduce the effect of attacks. The socialisation of collaboration in the domain of information security applies two essential theories: Social Bond Theory (SBT) and the Theory of Planned Behaviour (TPB). The results of the data analysis revealed that personal norms, involvement, and commitment significantly influence the employees’ attitude towards ISC intention. However, contrary to our expectation, attachment does not influence the attitude of employees towards ISC. In addition, attitudes towards ISC, perceived behavioural control, and personal norms significantly affect the intention towards ISC. The findings also show that the intention for ISC and organisational support positively influence ISC, but that trust does not significantly affect ISC behaviour.
    • Measuring community disaster resilience at local levels: An adaptable resilience framework

      Tariq, Hisham; Pathirage, Chaminda; Fernando, Terrence (Elsevier, 2021-05-28)
      Decision makers, practitioners and community members need to assess the disaster resilience of their communities and to understand better the risks they face from natural hazards. There is a lack of consensus on what resilience means and how it can be measured as each stakeholder potentially brings a different perspective to understanding community disaster resilience. The paper will identify the key features and characteristics of Community Disaster Resilience (CDR) frameworks from the literature to develop a resilience framework that can be adapted and customised according to stakeholder needs. The paper used a 5-step process to develop an adaptable CDR framework. First, a review of 36 resilience frameworks was conducted to identify key features and characteristics of resilience frameworks. In Steps 2 and 3, a matrix of indicators and measures was populated by resilience dimensions covered in the current CDR literature reviewed. Subsequently, the indicators were sorted for similarities and duplicates were removed. Finally, they were clustered by six critical resilience dimensions (i.e. Physical, Health, Economic, Environmental, Social and Governance) into a library of 86 resilience indicators (composed of 360 measures) that can be used to operationalize a CDR framework according to the needs of the stakeholders. The review indicated that majority of the articles selected use objective approaches to measure resilience showing a gap for more frameworks using subjective, or participatory, approaches to measuring community resilience. An adaptable CDR framework may make resilience assessment more grounded in local stakeholder perspectives and lead to a better understanding of community resilience.
    • Motivation and opportunity based model to reduce information security insider threats in organisations

      Safa, Nader Sohrabi; Maple, Carsten; Watson, Tim; Von Solms, Rossouw (Elsevier, 2018-03-05)
      Information technology has brought with it many advantages for organisations, but information security is still a major concern for organisations which rely on such technology. Users, whether with intent or through negligence, are a great source of potential of risk to information assets. A lack of awareness, negligence, resistance, disobedience, apathy and mischievousness are root causes of information security incidents in organisations. As such, insider threats have attracted the attention of a number of experts in this domain. Two particularly important considerations when exploring insider threats are motivation and opportunity. Two fundamental theories relating to these phenomena, and on which the research presented in this paper relies, are Social Bond Theory (SBT), which can be used to help undermine motivation to engage in misbehaviour, and Situational Crime Prevention Theory (SCPT), which can be used to reduce opportunities for misbehaviour. The results of our data analysis show that situational prevention factors such as increasing the effort and risk involved in a crime, reducing the rewards and removing excuses can significantly promotes the adoption of negative attitudes towards misbehaviour, though reducing provocations does not have any effect on attitudes. Further, social bond factors such as a commitment to organisational policies and procedures, involvement in information security activities and personal norms also significantly promotes the adoption of negative attitudes towards misbehaviour. However, attachment does not significantly promote an attitude of misbehaviour avoidance on the part of employees. Finally, our findings also show that a negative attitude towards misbehaviour influences the employees’ intentions towards engaging in misbehaviour positively, and this in turn reduces insider threat behaviour. The outputs of this study shed some light on factors which play a role in reducing misbehaviour in the domain of information security for academics and practitioners.
    • Physico-chemical and sensory acceptability of no added sugar chocolate spreads fortified with multiple micronutrients

      Tolve, Roberta; Tchuenbou-Magaia, Fideline; Verderese, Daniele; Simonato, Barbara; Puggia, Damiano; Galgano, Fernanda; Zamboni, Anita; Favati, Fabio (Elsevier, 2021-06-17)
      Vitamin D and magnesium-calcium carbonate nanoparticles were used to fortify a newly developed healthy chocolate spread formulated with inulin and maltitol as sugar replacers and alternative to palm oil to reduce the concentration of saturated fatty acid. These samples were compared with well-known commercially available chocolate spreads in terms of rheology, polyphenols content and in vitro digestion, sensory attributes and willingness to buy. The fortified chocolate spreads showed comparable if not better acceptability than the current products on the market and over 80% of the participants were inclined to buy and 66% prepared to spend 10 to 15% more money on the product enriched with the three micronutrients. The results also demonstrate that the incorporation of nanoparticles could affect the rheological and physio-chemical properties of the formulations and an appropriate ratio between the fat phase and particles seems an important factor to consider.
    • An opportunistic resource management model to overcome resource‐constraint in the Internet of Things

      Safa, Nader Sohrabi; Maple, Carsten; Haghparast, Mahboobeh; Watson, Tim; Dianati, Mehrdad (Wiley, 2018-09-25)
      Experts believe that the Internet of Things (IoT) is a new revolution in technology and has brought many advantages for our society. However, there are serious challenges in terms of information security and privacy protection. Smart objects usually do not have malware detection due to resource limitations and their intrusion detection work on a particular network. Low computation power, low bandwidth, low battery, storage, and memory contribute to a resource-constrained effect on information security and privacy protection in the domain of IoT. The capacity of fog and cloud computing such as efficient computing, data access, network and storage, supporting mobility, location awareness, heterogeneity, scalability, and low latency in secure communication positively influence information security and privacy protection in IoT. This study illustrates the positive effect of fog and cloud computing on the security of IoT systems and presents a decision-making model based on the object's characteristics such as computational power, storage, memory, energy consumption, bandwidth, packet delivery, hop-count, etc. This helps an IoT system choose the best nodes for creating the fog that we need in the IoT system. Our experiment shows that the proposed approach has less computational, communicational cost, and more productivity in compare with the situation that we choose the smart objects randomly to create a fog.
    • A survey of empirical performance evaluation of permissioned blockchain platforms: Challenges and opportunities

      Dabbagh, Mohammad; Choo, Kim-Kwang Raymond; Beheshti, Amin; Tahir, Mohammad; Safa, Nader Sohrabi (Elsevier, 2020-10-09)
      Blockchain-based platforms, particularly those based on permissioned blockchain, are increasingly popular in a broad range of settings. In addition to security and privacy concerns, organizations seeking to implement such platforms also need to consider performance, especially in latency- or delay-sensitive applications. Performance is generally less studied in comparison to security and privacy, and therefore in this paper we survey existing empirical performance evaluations of different permissioned blockchain platforms published between 2015 and 2019, using a comparative framework. The framework comprises ten criteria. We then conclude the paper with a number of potential future research directions.
    • Acidic amino acids as counterions of ciprofloxacin: Effect on growth and pigment production in Staphylococcus aureus NCTC 8325 and Pseudomonas aeruginosa PAO1

      Warraich, AA; Mohammed, AUR; Gibson, H; Hussain, M; Rahman, AS; Aston Pharmacy School, Aston University, Birmingham, United Kingdom. (Public Library of Science (PLoS), 2021-04-29)
      Antimicrobial resistance (AMR) is emerging as a global threat to public health. One of the strategies employed to combat AMR is the use of adjuvants which act to enhance or reinstate antimicrobial activity by inhibiting resistance mechanisms. However, these adjuvants are themselves not immune to selecting resistant phenotypes. Thus, there is a need to utilise mechanisms which are either less likely to or unable to trigger resistance. One commonly employed mechanism of resistance by microorganisms is to prevent antimicrobial uptake or efflux the antibiotic which manages to permeate its membrane. Here we propose amino acids as antimicrobial adjuvants that may be utilizing alternate mechanisms to fight AMR. We used a modified ethidium bromide (EtBr) efflux assay to determine its efflux in the presence of ciprofloxacin within Staphylococcus aureus (NCTC 8325) and Pseudomonas aeruginosa (PAO1). In this study, aspartic acid and glutamic acid were found to inhibit growth of both bacterial species. Moreover, a reduced production of toxic pigments, pyocyanin and pyoverdine by P. aeruginosa was also observed. As evident from similar findings with tetracycline, these adjuvants, may be a way forward towards tackling antimicrobial resistance.
    • A multivariant secure framework for smart mobile health application

      Butt, Shariq Aziz; Jamal, Tauseef; Azad, Muhammad Ajmal; Ali, Arshad; Safa, Nader Sohrabi (Wiley, 2019-08-06)
      Wireless sensor network enables remote connectivity of technological devices such as smart mobile with the internet. Due to its low cost as well as easy availability of data sharing and accessing devices, the Internet of Things (IoT) has grown exponentially during the past few years. The availability of these devices plays a remarkable role in the new era of mHealth. In mHealth, the sensors generate enormous amounts of data and the context-aware computing has proven to collect and manage the data. The context aware computing is a new domain to be aware of context of involved devices. The context-aware computing is playing a very significant part in the development of smart mobile health applications to monitor the health of patients more efficiently. Security is one of the key challenges in IoT-based mHealth application development. The wireless nature of IoT devices motivates attackers to attack on application; these vulnerable attacks can be denial of service attack, sinkhole attack, and select forwarding attack. These attacks lead intruders to disrupt the application's functionality, data packet drops to malicious end and changes the route of data and forwards the data packet to other location. There is a need to timely detect and prevent these threats in mobile health applications. Existing work includes many security frameworks to secure the mobile health applications but all have some drawbacks. This paper presents existing frameworks, the impact of threats on applications, on information, and different security levels. From this line of research, we propose a security framework with two algorithms, ie, (i) patient priority autonomous call and (ii) location distance based switch, for mobile health applications and make a comparative analysis of the proposed framework with the existing ones.
    • Incremental algorithm for association rule mining under dynamic threshold

      Aqra, Iyad; Abdul Ghani, Norjihan; Maple, Carsten; Machado, José; Sohrabi Safa, Nader (MDPI AG, 2019-12-10)
      Data mining is essentially applied to discover new knowledge from a database through an iterative process. The mining process may be time consuming for massive datasets. A widely used method related to knowledge discovery domain refers to association rule mining (ARM) approach, despite its shortcomings in mining large databases. As such, several approaches have been prescribed to unravel knowledge. Most of the proposed algorithms addressed data incremental issues, especially when a hefty amount of data are added to the database after the latest mining process. Three basic manipulation operations performed in a database include add, delete, and update. Any method devised in light of data incremental issues is bound to embed these three operations. The changing threshold is a long-standing problem within the data mining field. Since decision making refers to an active process, the threshold is indeed changeable. Accordingly, the present study proposes an algorithm that resolves the issue of rescanning a database that had been mined previously and allows retrieval of knowledge that satisfies several thresholds without the need to learn the process from scratch. The proposed approach displayed high accuracy in experimentation, as well as reduction in processing time by almost two-thirds of the original mining execution time.
    • Deterrence and prevention-based model to mitigate information security insider threats in organisations

      Safa, Nader Sohrabi; Maple, Carsten; Furnell, Steve; Azad, Muhammad Ajmal; Perera, Charith; Dabbagh, Mohammad; Sookhak, Mehdi (Elsevier, 2019-03-12)
      Previous studies show that information security breaches and privacy violations are important issues for organisations and people. It is acknowledged that decreasing the risk in this domain requires consideration of the technological aspects of information security alongside human aspects. Employees intentionally or unintentionally account for a significant portion of the threats to information assets in organisations. This research presents a novel conceptual framework to mitigate the risk of insiders using deterrence and prevention approaches. Deterrence factors discourage employees from engaging in information security misbehaviour in organisations, and situational crime prevention factors encourage them to prevent information security misconduct. Our findings show that perceived sanctions certainty and severity significantly influence individuals’ attitudes and deter them from information security misconduct. In addition, the output revealed that increasing the effort, risk and reducing the reward (benefits of crime) influence the employees’ attitudes towards prevent information security misbehaviour. However, removing excuses and reducing provocations do not significantly influence individuals’ attitudes towards prevent information security misconduct. Finally, the output of the data analysis also showed that subjective norms, perceived behavioural control and attitude influence individuals’ intentions, and, ultimately, their behaviour towards avoiding information security misbehaviour.
    • Managing knowledge in the context of smart cities: a systematic review

      Abdalla, Wala; Renukappa, Suresh; Suresh, Subashini; Al Nabt, Saeed (Academic Conferences International, 2021-12-31)
      The most recent view on smart city development has recognized that the level of technology adoption in urban contexts is no more able to reflect the real smartness of cities. Smart cities is seen as a centre of knowledge, education, and creativity. The development of smart cities is becoming more and more knowledge based. As a result, knowledge has been perceived as the core component that makes cities smart. Hence, to take advantage of the opportunities that knowledge-based economy and society can bring to the city, leaders and decision makers need to develop cities that take advantage of local knowledge and intellectual capital of the population. Therefore, they need to take initiative to adapt Knowledge Management (KM) in smart cities development. Smart cities KM offers the means to create valuable knowledge that brings consistent and sustainable added value that can therefore be useful in avoiding strategic risk, better-informed decision, and finding smart and effective business solutions. However, smart cities is a relatively new concept that still raises many questions related to its relevance in knowledge management studies. This often calls for the creation, use, capture and exploitation of new knowledge. Therefore, managing this knowledge is considered an important source of sustainable competitive advantage. However, only a few studies in the academic literature on smart city initiatives address issues related to managerial and knowledge management perspectives. This paper investigates the underlying dynamics behind KM and the need for successful implementation of KM strategies within the context of smart cities. The findings are in the main, based on thorough review of literature. It reviews the concept of smart cities and KM. The paper concludes that effectiveness of smart cities knowledge creation, exploitation and management significantly influences on effectiveness of smart city development. Therefore, smart cities governance must be able to exploit and manage knowledge that results from smart cities development.
    • Future directions and requirements for tissue engineering biomaterials

      Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Praveen, Ayyappan S; Pollard, Andrew; Wang, Chang (Elsevier, 2021-02-24)
      A wide array of biomaterials are being developed to be used as tissue engineering scaffolds, including metals, ceramics, polymers, and composites. For all biomaterials, the challenge remains to achieve functionality to mimic the biomechanical environment, induce bioactivity, and support critical size tissue reintegration. This calls for a functional evolution in biomaterials to be used as tissue engineering constructs for partial and full tissue reconstruction. When characterizing biomaterials for tissue engineering, the relevant extensions include engineered surfaces, micro-patterns, and porous architectures along with, bioactive, bioresorbable, and infection resistant properties. Accordingly, functional biomaterials will drive the next generation of tissue engineering constructs. This paper, therefore, explores the major concepts, future direction, and recent signs of progress in the field of tissue engineering biomaterials. Traditional materials are not discounted entirely as bioinert materials are still relevant and emerging research offers new functionalities for them to support drug, gene, and cell tissue engineering. Therefore, an attempt is also made to explain how the requirements of biomaterials are changing to facilitate, sustain, control, and proliferate engineered tissue. The article begins with a brief introduction to the evolution of biomaterials followed by a commentary on their functional requirements when applied to tissue engineering. This is followed by an exploratory evaluation of key tissue engineering constructs and their qualifiers while systematically identifying their future direction and potential.
    • A LogitBoost-based algorithm for detecting known and unknown web attacks

      Kamarudin, Muhammad Hilmi; Maple, Carsten; Watson, Tim; Safa, Nader Sohrabi (Institute of Electrical and Electronics Engineers (IEEE), 2017-11-03)
      The rapid growth in the volume and importance of web communication throughout the Internet has heightened the need for better security protection. Security experts, when protecting systems, maintain a database featuring signatures of a large number of attacks to assist with attack detection. However used in isolation, this can limit the capability of the system as it is only able to recognize known attacks. To overcome the problem, we propose an anomaly-based intrusion detection system using an ensemble classification approach to detect unknown attacks on web servers. The process involves removing irrelevant and redundant features utilising a filter and wrapper selection procedure. Logitboost is then employed together with random forests as a weak classifier. The proposed ensemble technique was evaluated with some artificial data sets namely NSL-KDD, an improved version of the old KDD Cup from 1999, and the recently published UNSW-NB15 data set. The experimental results show that our approach demonstrates superiority, in terms of accuracy and detection rate over the traditional approaches, whilst preserving low false rejection rates.
    • Privacy enhancing technologies (PETs) for connected vehicles in smart cities

      Safa, Nader Sohrabi; Mitchell, Faye; Maple, Carsten; Azad, Muhammad Ajmal; Dabbagh, Mohammad (Wiley, 2020-11-18)
      Many Experts believe that the Internet of Things (IoT) is a new revolution in technology that has brought many benefits for our organizations, businesses, and industries. However, information security and privacy protection are important challenges particularly for smart vehicles in smart cities that have attracted the attention of experts in this domain. Privacy Enhancing Technologies (PETs) endeavor to mitigate the risk of privacy invasions, but the literature lacks a thorough review of the approaches and techniques that support individuals' privacy in the connection between smart vehicles and smart cities. This gap has stimulated us to conduct this research with the main goal of reviewing recent privacy-enhancing technologies, approaches, taxonomy, challenges, and solutions on the application of PETs for smart vehicles in smart cities. The significant aspect of this study originates from the inclusion of data-oriented and process-oriented privacy protection. This research also identifies limitations of existing PETs, complementary technologies, and potential research directions.
    • Smart tribological coating

      Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Olabi, Abdul-Ghani (Elsevier, 2021)
      Materials that can adapt their characteristics favorably to relevant external factors are defined as smart materials. The term “smart tribological coatings” defines a class of coatings that are capable of responding to their environment while offering an advantageous functionality while preserving their tribological property. The latest approach in coatings is to manipulate the material and structural composition of the deposition at submicron scales to develop functional architecture. This sequential fabrication of submicron layers featuring unique material compositions and topography result in unique and exotic properties suitable for the development of smart coatings. Several such smart coating architectures have been conceived and investigated by researchers that are summarized in this study. Notable examples of such coatings include sensing, self-healing, self-lubricating, self-cleaning, and bioactive systems. Surface architectures with enhanced and novel functionalities such as self-stratifying, super-insulating and thermochromic are also emerging and are likely to become part of the smart coating portfolio. This article starts by briefly introducing the primary concepts associated with smart tribological coatings along with their functionalities. The different types of coating structures and their smart characteristics are discussed in subsequent sections. Altogether, the article brings together the various concepts in smart tribological coatings that offer significant potential for a range of functional applications.
    • Nanomaterials theory and applications

      Govindaraman, Loganathan T; Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Ramadan, Mohamad; Olabi, Abdul-Ghani (Elsevier, 2021-06-01)
      The behavior of matter at the nanoscale alters material properties in comparison to their bulk counterparts. Overall, materials at the nano-range demonstrate modified physical behaviors that offer favorable mechanical, thermodynamic, magnetic, optical, and biomedical properties for a range of applications. As such nanomaterials have their prominence in most scientific domains due to their ability to generate varied responses suitable for specific requirements. However, the implementation of nanomaterials in each situation requires a detailed understanding of the chemical and physical properties of the base materials, control parameters, and methods of fabrication. This paper introduces nanomaterials, their classification and measurement techniques followed by synthesis methods, common properties, applications, and prospects.
    • Tissue engineering concept

      Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Wang, Chang (Elsevier, 2021)
      Tissue engineering is a multidisciplinary methodology regarding the development of new tissue that can restore, maintain, or improve damaged tissues or whole organs. The conventional concept in tissue engineering features three distinct elements namely, cells, scaffolds, and bioactive factors, each having its characteristic role. Over the years, new concepts have evolved such as scaffold and cell-free architectures bringing new opportunities and challenges. The cell-free concept uses highly specialized biomaterials to create a bioresponsive scaffold that aids in vivo tissue regeneration. The scaffold-free concept, on the other hand, employs cell sheets, spheroids, or tissue strands as the fundamental building blocks replacing the conventional scaffold. The paper starts by introducing the primary elements associated with tissue engineering along with their functionalities. The various tissue engineering concepts are presented in subsequent sections and upcoming approaches such as bioprinting discussed. As such the paper brings together the various concepts in tissue engineering that offer significant potential for the generation of functional tissues and organs.