Evaluation of RPL’s Single Metric Objective Functions

In this paper, we evaluate the performance of RPL (IPv6 Routing Protocol for Low Power and Lossy Networks) based on the Objective Function being used to construct the Destination Oriented Directed Acyclic Graph (DODAG). Using the Cooja simulator, we compared Objective Function Zero (OF0) with the Minimum Rank with Hysteresis Objective Function (MRHOF) in terms of average power consumption, packet loss ratio, and average end-to-end latency. Our study shows that RPL performs better in terms of packet loss ratio and average endto-end latency when MRHOF is used as an objective function. However, the average power consumption is noticeably higher compared to OF0

“It is Magic”: A Global Perspective on what Technology Means to Youth

As technology becomes ever more pervasive, it is increasingly important to understand the relationships between technology and youth. We seek to understand this bond at a global level. We have conducted focus groups and\ud video diaries with middle-school aged children in three different countries: Hungary, India, and Morocco. Our exploration has yielded five themes highlighting the emotional perspectives of youth regarding the devices in their everyday lives: 1) awe and appreciation, 2) fun and entertainment, 3) boredom, 4) communication, and 5) negativity. This paper discusses these themes and their\ud significance

Culturally Appropriate Acceptance Models for Civic Engagement Systems in Saudi Arabia

Information systems that support civic engagement for the public good are a promising new category of technology-mediated social participation. However, adoption of these smart-phone enabled systems varies widely across countries. Building off existing research on how culture mediates technology acceptance, we seek to develop a culturally appropriate model from the ground up that can help explain this cross-cultural difference, with a specific focus on the Kingdom of Saudi Arabia as a test case. This process involves mapping constructs from existing models, such as UTAUT, and theories, such as the Expectancy Theory of Motivation, to the cultural context and developing new contracts when no appropriate match is available. This paper reports early results from field work conducted in Saudi Arabia to generate these mappings._x000D_ _x000D_ Keywords: Technology Acceptance, Civic Engagement, Culture, Context, Kingdom of Saudi Arabia, Model Development, Technology Mediated Social Participation System

Active security vulnerability notification and resolution

The early version of the Internet was designed for connectivity only, without the consideration of security, and the Internet is consequently an open structure. Networked systems are vulnerable for a number of reasons; design error, implementation, and management. A vulnerability is a hole or weak point that can be exploited to compromise the security of the system. Operating systems and applications are often vulnerable because of design errors. Software vendors release patches for discovered vulnerabilities, and rely upon system administrators to accept and install patches on their systems. Many system administrators fail to install patches on time, and consequently leave their systems vulnerable to exploitation by hackers. This exploitation can result in various security breaches, including website defacement, denial of service, or malware attacks. The overall problem is significant with an average of 115 vulnerabilities per week being documented during 2005. This thesis considers the problem of vulnerabilities in IT networked systems, and maps the vulnerability types into a technical taxonomy. The thesis presents a thorough analysis of the existing methods of vulnerability management which determine that these methods have failed to mange the problem in a comprehensive way, and show the need for a comprehensive management system, capable of addressing the awareness and patch deploymentp roblems. A critical examination of vulnerability databasess tatistics over the past few years is provided, together with a benchmarking of the problem in a reference environment with a discussion of why a new approach is needed. The research examined and compared different vulnerability advisories, and proposed a generic vulnerability format towards automating the notification process. The thesis identifies the standard process of addressing vulnerabilities and the over reliance upon the manual method. An automated management system must take into account new vulnerabilities and patch deploymentt o provide a comprehensives olution. The overall aim of the research has therefore been to design a new framework to address these flaws in the networked systems harmonised with the standard system administrator process. The approach, known as AVMS (Automated Vulnerability Management System), is capable of filtering and prioritising the relevant messages, and then downloading the associated patches and deploying them to the required machines. The framework is validated through a proof-of-concept prototype system. A series of tests involving different advisories are used to illustrate how AVMS would behave. This helped to prove that the automated vulnerability management system prototype is indeed viable, and that the research has provided a suitable contribution to knowledge in this important domain.The Saudi Government and the Network Research Group at the University of Plymouth

Analytical Hierarchy Process Multi-Metric Objective Function for RPL

IPv6 Routing Protocol for Low Power and Lossy Networks (RPL), is based on building an acyclic graph where an Objective Function (OF) is responsible for selecting the preferred parent during Destination Oriented Directed Acyclic Graph (DODAG) construction. In this paper, we propose a new multi-metric OF based on Analytical Hierarchy Processes decision masking algorithm. AHP-OF, combines a set of routing metrics aiming to provide the best routing decision for RPL to satisfy the different application requirements for LLN s such as reliable applications, real time applications and highly available applications. Here we focus on the theoretical aspect of AHP-OF, and finally we evaluate the performance of AHP-OF compared to other OFs using Cooja simulator

The effect of photoinitiator systems on resin-based composite containing ZnO-nanoparticles

ObjectiveZinc oxide (ZnO) powder possesses antibacterial activity and although white in color, it can severely reduce the depth of cure (DoC) of resin-based composite (RBC). This study investigated the effect of unary and binary photoinitiator systems on the DoC and degree of conversion (DC) of formulated RBC containing ZnO-nanoparticles.MethodsFourteen RBCs (n = 3/group) were formulated consisting of 50 wt% mixture of monomers (Bis-GMA, TEGDMA, and UDMA) and 50 wt% fillers (inert barium glass powder and silica nanoparticles). ZnO-nanoparticles were added at 0 (control), 0.5, 1, 1.5 and 2 wt%. A unary initiator system consists of camphorquinone (CQ) 0.25, 0.5 and 1 wt% and ethyl 4-(dimethylamino)benzoate (EDMAB) 0.75 wt% or a binary initiator system consisting of diphenyliodonium hexafluorophosphate (DPI) 0.25, 0.5 and 1 wt%, CQ 0.25, 0.5 and 1 wt% and EDMAB 0.75 wt% were added to the monomer mixture. To measure the DoC, each specimen was prepared in a custom-made mold with a slot (16 x 8×2 mm) and a top cover plate, irradiated from one end (40 s), stored dry (37° C, 1 d) and measured at increasing depths using Vickers hardness (0.5 mm intervals). 1 mm thick specimens were prepared to measure DC continuously using FTIR, from zero up to 24 h post-irradiation.ResultsIncreasing the concentrations of ZnO led to a significant reduction of DoC (p < 0.05). But most of the binary initiator groups showed significantly higher DoC (p < 0.05). Depth, at 80 % of max VHN, of unary initiator groups reduced from 6.8 mm (ZnO at 0 wt%) to 2.1 mm (ZnO at 2 wt%) and in binary initiator groups from 8.4 mm to 2.3 mm. Groups with lower photoinitiator concentrations (0.25 wt%) showed a significant increase in DoC compared with groups with higher concentrations (1 wt%) (p < 0.05). DC after 24 h was independent of either ZnO concentration or the photoinitiator system (p > 0.05). However, faster conversions were observed in binary initiator groups. The RPmax of binary groups ranged from 8.1 % to 10.1 %/s, and unary groups ranged from 5.2 % to 7.2 %/s.SignificanceThe addition of DPI resulted in an overall increased curing depth, which was enhanced when lower concentrations of photoinitiators were used. Also, DPI resulted in faster conversions. This is desirable in designing antibacterial RBC containing ZnO

Gas chromatography-mass spectrometry (GC-MS) analysis and in vitro evaluation of antioxidant and antimicrobial activities of various solvent extracts from Citrullus colocynthis (L.) roots to control pathogen and spoilage bacteria

Citrullus colocynthis (L.) schrad is an important medicinal plant belonging to the family of Cucurbitaceae. In the present study we evaluated in vitro the antimicrobial and the antioxidant properties of various solvent extracts from C. colocynthis roots as well as the latter phytochemical characterisation. Total phenolic and flavonoid contents were determined. The highest content of total phenolic was found in extracts obtained with ethyl acetate (205 mg GAE/g) followed by methanol (85 mg GAE/g). The major phenolic compounds in ethyl acetate extract were identified by gas chromatography-mass spectrometry (GC-MS). A total of 12 compounds were characterized including oleic acid, linoleic acid, caffeic acid, hexadecanoic acid and octadecanoic acids. The antioxidant activities were evaluated using 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) and lipid peroxidation methods. These tests showed that the ethyl acetate extract exhibited the best performance. The different extracts were also tested against a panel of pathogen, food-borne and spoilage bacteria and fungi in order to evaluate the antimicrobial properties of this plant. Among the tested extracts, only the ethyl acetate extract exhibited bactericidal and fungicidal activities. To our knowledge, this is the first report on the chemical composition, antioxidant and antimicrobial activities of phenolic extracts from C. colocynthis roots. The results of the present work indicate that C. colocynthis extracts could be used as natural antioxidant and antimicrobial agents in the food preservation and human health.Key words: Citrullus colocynthis, antibacterial activity, antifungal activity, antioxidant activity, phenolics composition

Development of Time-Resolved Diffuse Optical Systems Using SPAD Detectors and an Efficient Image Reconstruction Algorithm

Time-Resolved diffuse optics is a powerful and safe technique to quantify the optical properties (OP) for highly scattering media such as biological tissues. The OP values are correlated with the compositions of the measured objects, especially for the tissue chromophores such as hemoglobin. The OP are mainly the absorption and the reduced scattering coefficients that can be quantified for highly scattering media using Time-Resolved Diffuse Optical Spectroscopy (TR-DOS) systems. The OP can be retrieved using Time-Resolved Diffuse Optical Imaging (TR-DOI) systems to reconstruct the distribution of the OP in measured media. Therefore, TR-DOS and TR-DOI can be used for functional monitoring of brain and muscles, and to diagnose some diseases such as detection and localization for breast cancer and blood clot. In general, TR-DOI systems are non-invasive, reliable, and have a high temporal resolution. TR-DOI systems have been known for their complexity, bulkiness, and costly equipment such as light sources (picosecond pulsed laser) and detectors (single photon counters). Also, TR-DOI systems acquire a large amount of data and suffer from the computational cost of the image reconstruction process. These limitations hinder the usage of TR-DOI for widespread potential applications such as clinical measurements. The goals of this research project are to investigate approaches to eliminate two main limitations of TR-DOI systems. First, building TR-DOS systems using custom-designed free-running (FR) and time-gated (TG) SPAD detectors that are fabricated in low-cost standard CMOS technology instead of the costly photon counting and timing detectors. The FR-TR-DOS prototype has demonstrated comparable performance (for homogeneous objects measurements) with the reported TR-DOS prototypes that use commercial and expensive detectors. The TG-TR-DOS prototype has acquired raw data with a low level of noise and high dynamic range that enable this prototype to measure multilayered objects such as human heads. Second, building and evaluating TR-DOI prototype that uses a computationally efficient algorithm to reconstruct high quality 3D tomographic images by analyzing a small part of the acquired data. This work indicates the possibility to exploit the recent advances in the technologies of silicon detectors, and computation to build low-cost, compact, portable TR-DOI systems. These systems can expand the applications of TR-DOI and TR-DOS into several fields such as oncology, and neurology.ThesisDoctor of Philosophy (PhD

Effect on hygroscopic characteristics of n‐ZnO additions to resin composite

This study investigates the effect of adding different amounts of n-ZnO to model resin-based composites on their hygroscopic characteristics. Six groups (n = 5) were formulated using Bis-GMA, TEGDMA, UDMA, inert barium glass powder, silica nanoparticles, and varying amounts of n-ZnO (0–5 wt.%). The photoinitiator system included camphorquinone, diphenyliodonium hexafluorophosphate, and ethyl 4-(dimethylamino) benzoate. Sorption, solubility, and hygroscopic expansion specimens were prepared following ISO 4049:2019 and immersed in water for 168 days. Sorption and solubility were assessed with an analytical balance, while hygroscopic expansion was measured using a laser scan micrometer. Zn2+ release was analyzed using ICP-MS (n = 3). Increasing n-ZnO concentrations significantly reduced sorption and solubility, with the control (0 wt.% n-ZnO) showing the highest values (28.7 and 2.1 μg/mm3) and the 2 wt.% n-ZnO group showing the lowest (27 μg/mm3, −0.4 μg/mm3). However, increasing the concentrations of n-ZnO significantly increased the hygroscopic expansion. The volumetric expansion for the lowest (control) and highest (n-ZnO at 3 wt.%) was 1.63% and 1.87%, respectively. ICP-MS revealed progressively higher Zn2+ release with increasing n-ZnO concentration, peaking at 675.1 ppb in the 5 wt.% group. Overall, n-ZnO reduced sorption and solubility while increasing expansion and Zn2+ release, with all formulations meeting ISO 4049 standards

Impact of E-Marketing on Consumer Buying Behavior

In this modern and mechanized world the businesses area doping a number of tools and techniques for marketing. However all the tools are deriving results but the most updated method of marketing is the electronic marketing. It is the method of marketing that derives more target customers as compared to the other techniques. Researchers have sown that since the technology has updated and today the customers are aware of the technology. The customers are more interested in the social media websites and the applications. Hence these applications have becomea good spot of advertisements and promotion. Similarly the search engines are offering adds policy that derives the customers in thebusiness and ultimately maximizes the revenues for the business