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Riaz, Rabia,Ali, Mumtaz,Sahito, Iftikhar Ali,Arbab, Alvira Ayoub,Maiyalagan, T.,Anjum, Aima Sameen,Ko, Min Jae,Jeong, Sung Hoon Elsevier BV * North-Holland 2019 Applied Surface Science Vol.480 No.-
<P><B>Abstract</B></P> <P>Nitrogen-doped graphene quantum dots (N-GQDs) are emerging electroactive and visible light active organic photocatalysts, known for their high stability, catalytic activity and biocompatibility. The edge surfaces of N-GQDs are highly active, however, when N-GQDs make the film the edges are not fully exposed for catalysis. To avoid this issue, the N-GQDs are shaped to branched leaf shape, with an extended network of voids, offering highly active surfaces (edge) exposed for electrocatalytic and photocatalytic activity. The nitrogen doping causes a decrease in the bandgap of N-GQDs, thus enabling them to be superb visible light photocatalyst, for degradation of Methylene blue dye from water. Photoluminescence results confirmed that by a synergistic combination of the highly conductive substrate; Carbon fabric coated graphene sheets (CF-rGO) the recombination of photogenerated excitons is significantly suppressed, hence enabling their efficient utilization for catalysis. Comparatively, uniformly coated N-GQDs showed 49.3% lower photocatalytic activity, owing to their hidden active sites. The degradation was further boosted by 30% by combining the electrocatalytic activity, i.e. electro-photocatalysis of the proposed electrode. The proposed electrode material was analyzed using TEM, FE-SEM, FTIR, AFM, and WA-XRD, whereas the stability of electrode was confirmed by TGA, tensile test, bending test, and in harsh chemical environments. The proposed photo-electrocatalyst electrode is binder-free, stable, flexible and highly conductive, which makes the electrode quite suitable for flexible catalytic devices like flexible solar cells and wearable supercapacitors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A flexible electrode is fabricated using self-assembled overlayer of Nitrogen doped Graphene Quantum Dots (N-GQDs). </LI> <LI> Self-assembeled highly porous leaflets structure has maximum exposed edge surfaces to accelarate the catalytic reaction. </LI> <LI> The proposed electrode is metal free and is stable at high temperature, harsh chemical environments, and mechanical stresses. </LI> <LI> The surface resistance of the all carbon electrode is only 2.5 Ω sq.<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Nitrogen doped graphene quantum dots (N-GQDs) were self-assembled (with high porosity) on reduced graphene oxide coated carbon fabric to fabricate a highly stable visible light photocatlytically and electrocatalytically active flexible electrode for water treatment.</P> <P>[DISPLAY OMISSION]</P>
BAS: The Biphase Authentication Scheme for Wireless Sensor Networks
Riaz, Rabia,Chung, Tae-Sun,Rizvi, Sanam Shahla,Yaqub, Nazish Hindawi Limited 2017 Security and communication networks Vol.2017 No.-
<P>The development of wireless sensor networks can be considered as the beginning of a new generation of applications. Authenticity of communicating entities is essential for the success of wireless sensor networks. Authentication in wireless sensor networks is always a challenging task due to broadcast nature of the transmission medium. Sensor nodes are usually resource constrained with respect to energy, memory, and computation and communication capabilities. It is not possible for each node to authenticate all incoming request messages, whether these request messages are from authorized or unauthorized nodes. Any malicious node can flood the network by sending messages repeatedly for creating denial of service attack, which will eventually bring down the whole network. In this paper, a lightweight authentication scheme named as Biphase Authentication Scheme (BAS) is presented for wireless sensor networks. This scheme provides initial small scale authentication for the request messages entering wireless sensor networks and resistance against denial of service attacks.</P>
Outlier Detection in Indoor Localization and Internet of Things (IoT) using Machine Learning
Mansoor Ahmed Bhatti,Rabia Riaz,Sana Shokat,Farina Riaz,Se Jin Kwon 한국통신학회 2020 Journal of communications and networks Vol.22 No.3
In Internet of things (IoT) millions of devices are intelligently connected for providing smart services. Especially in indoor localization environment, that is one of the most concerningtopic of smart cities, internet of things and wireless sensor networks. Many technologies are being used for localization purposein indoor environment and Wi-Fi using received signal strengths(RSSs) is one of them. Wi-Fi RSSs are sensitive to reflection, refraction, interference and channel noise that cause irregularity insignal strengths. The irregular and anomalous RSS values, used ina Wi-Fi indoor localization environment, cannot define the locationof any unknown node correctly. Therefore, this research has developed an outlier detection technique named as iF_Ensemblefor Wi-Fi indoor localization environment by analyzing RSSs using the combination of supervised, unsupervised and ensemble machine learning methods. In this research isolation forest (iForest)is used as an unsupervised learning method. Supervised learningmethod includes support vector machine (SVM), K-nearest neighbor (KNN) and random forest (RF) classifiers with stacking thatis an ensemble learning method. For the evaluation purpose accuracy, precision, recall, F-score and ROC-AUC curve are used. Theevaluation of used machine learning method provides high accuracy of 97.8 percent with proposed outlier detection methods andalmost 2 percent improvement in the accuracy of localization process in indoor environment after eliminating outliers.
Mumtaz Ali,Muhammad Zeeshan,Muhammad Bilal Qadir,Rabia Riaz,Sheraz Ahmad,Yasir Nawab,Aima Sameen Anjum 한국섬유공학회 2018 Fibers and polymers Vol.19 No.11
Auxetic materials expand in at least one dimension, when stretched longitudinally i.e. they have negative Poisson’s ratio. Development of 2D woven auxetic fabrics (AF) is a new approach to develop mechanically stable auxetic textile structures. However, the mechanical response of such emerging structure is still not studied in detail yet, therefore different mechanical properties of 2D woven AF are compared with conventional non-auxetic fabric (NAF). AF was developed by orienting yarns in auxetic honey-comb (AHC) geometry and auxeticity is induced due to such orientation of yarns. AF was developed using conventional (non-auxetic) materials; cotton yarn and elastane cotton yarn in warp and weft dimension respectively, using air jet loom. Structure and auxeticity of AF were analyzed using a digital microscope and its different mechanical properties (tensile strength, tear strength, bursting strength, cut resistance, and puncture resistance) were studied. AF showed superior mechanical properties with a lower initial modulus, which is beneficial for different protective textiles applications like cut resistance gloves, blast resistant curtains, and puncture tolerant elastomeric composites.