761 research outputs found
Safety Effectiveness of Conversion of Two-Way-Left-Turn Lanes into Raised Medians
Two way left turn lanes (TWLTL) and raised medians are common median treatments on roadways. This research focused on evaluating the safety effectiveness of conversion of TWLTLs into raised medians using Before-After and Cross Sectional Studies. In the Before-After Studies, we evaluated the effect of this treatment using the Naive, Before-After with Comparison Group (CG), and Before-After with Empirical Bayes (EB) Methods. In order to apply these methods, a total of 33 segments of a treated group and 109 segments of a comparison group have been collected. Also, safety performance functions (SPFs) have been developed using the negative binomial model in order to calibrate crash modification factors (CMF) using the Before-After with Empirical Bayes Method. This research also evaluated the safety effectiveness of this treatment on four and six lane roads using Before-After with CG and Before-After with EB. The type of raised medians was further evaluated using Before-After with CG and EB. In sum, the results from this study show that applying the before-After and Cross Sectional studies have proved that the conversion from a TWLTL to a raised median helped to reduce total, fatal and injury, head on, angle, and left turn crashes. It significantly reduces crashes for head-on and left turn crashes, by restricting turning maneuvers. Also, this study has proved that the treatment is more effective on four rather than six lane roads. Furthermore, two types of raised medians, concrete and lawn curb, were evaluated after the conversion from TWLTLs. It was found that both medians have similar effects due to the conversion, and both median types helped in reducing the number of crashes
High Resolution Gravity, Helicopter Magnetic, and Electromagnetic Study, Haile Gold Mine, South Carolina
The goal of this research was to calibrate and test geophysical methods for the detection of disseminated sulfides in the area of the Haile Gold Mine, South Carolina. The work focused on the calibration of high resolution gravity, and helicopter electromagnetic (EM) and magnetic data provided by OceanaGold. While high resolution potential field data (gravity and magnetics) has not been proven to be effective at small scales in exploration for disseminated sulfides, there is a strong regional correlation between high amplitude gravity and magnetic anomalies and the most productive gold mines in the Carolina terrane. Helicopter EM methods have been shown to be effective in distinguishing sedimentary from volcanic-dominated sediments in the metamorphic rocks of the Carolina terrane. The interpretation of the gravity and magnetic data utilized tilt derivatives, reduced to pole anomalies (RTP), shaded relief, Power spectrum, Analytical signal, Source parameter imaging (SPI), 3-D Euler deconvolution, upward continuation, and 2-D forward density modeling. The most surprising result was that over the Haile Mine, the residual gravity anomalies, tilt derivatives, and analytic signal show positive anomalies correlated with the location of a disseminated ore body. The gravity field over the ore body can be interpreted as produced by 4% pyrite and molybdenite.
Electromagnetic (EM) anomalies are also spatially associated with the Haile ore bodies. Cultural signals in the EM data can be minimized with high pass filtering. The edges of a granite pluton are clearly illuminated by the shaded relief, tilt derivative, Euler deconvolution, and analytic signal of the high resolution magnetic field. The RTP magnetic field shows NW-trending Jurassic dikes as well as ENE-trending Alleghanian dikes. An oval pattern in the magnetic SPI outlines the Brewer gold mine area
The Quality Of Saudi Accreditation Standards For Distance Learning: Benchmarking And Expert Validation
The quality of distance learning is a concern among different stakeholders. An online learning degree is recognized in some countries while it is not accredited in others. Saudi Arabia is one of these countries that have skepticism in the quality of distance learning. It also has specific conditions for accrediting distance learning programs. Saudi Arabia recently has developed accreditation standards to ensure the quality of this learning mode but Saudi universities have not adopted the standards yet. Thus, the quality of these standards has not been tested yet. Therefore, this study investigates the quality of these standards by applying the methodology of benchmarking to compare their quality to frequently cited quality models for online learning and to aspirational countries in the West (US, UK, and Australia) and to peer countries in Asia (South Korea, Malaysia, and Sri Lanka) and Arabic Region (Jordan and United Arab Emirates (UAE)). It also explores the differences and similarities in the regulations of distance learning accreditation between these 8 countries and Saudi Arabia. The study also validates the standards in a survey design using experts’ rating to the relevance and importance of the Saudi standards for quality distance learning. The findings revealed an overall quality of the Saudi standards based on benchmarking and experts’ rating. Suggestions have been made to improve or change very few quality indicators. The regulations and rules for accrediting distance learning in Saudi Arabia are found to be strict in comparison to other countries. Therefore, the study also recommended policy makers in Saudi Arabia to adopt some of the regulations and standards of distance learning accreditation available in some of the aspirational and peer countries. Other recommendations have been suggested to different stakeholders including higher education institutions, instructional designers, and program directors
Towards Lightweight Secure User-Transparent And Privacy-Preserving Web Metering
Privacy is an issue today as more people are actively connecting and participating in the Internet. Problems arise when such concerning issue is coupled with security requirements of online applications. The web metering problem is the problem of counting the number of visits done by users to a webserver, additionally capturing data about these visits. There are trade-o s between designing secure web metering solutions and preserving users' privacy. There is also a dilemma between privacy preserving solutions versus accuracy of results. The problem becomes more difficult when the main interacting party, the user, is not inherently interested to participate and operations need to be carried out transparently. This thesis addresses the web metering problem in a hostile environment and proposes different web metering solutions. The web metering solutions operate in an environment where webservers or attackers are capable of invading users' privacy or modifying the web metering result. Threats in such environment are identified, using a well established threat model with certain assumptions, which are then used to derive privacy, security and functional requirements. Those requirements are used to show shortcomings in previous web metering schemes, which are then addressed by our proposed solutions. The central theme of this thesis is user's privacy by user-transparent solutions. Preserving users' privacy and designing secure web metering solutions that operate transparently to the user are two main goals of this research. Achieving the two goals can conflict with other requirements and such exploration was missed by former solutions in the literature. Privacy issues in this problem are the result of the dilemma of convincing interested parties of web metering results with sufficient details and non-repudiation evidence that can still preserve users' privacy. Relevant privacy guidelines are used to discuss and analyse privacy concerns in the context of the problem and consequently privacy-preserving solutions are proposed. Also, improving the usability through \securely" redesigning already used solutions will help into wider acceptance and universal deployment of the new solutions. Consequently, secure and privacy-preserving web metering solutions are proposed that operate transparently to the visitor. This thesis describes existing web metering solutions and analyses them with respect to different requirements and desiderata. It also describes and analyses new solutions which use existing security and authentication protocols, hardware devices and analytic codes. The proposed solutions provide a reasonable trade-o among privacy, security, accuracy and transparency. The first proposed solution, transparently to the user, reuses Identity Management Systems and hash functions for web metering purposes. The second hardware-based solution securely and transparently uses hardware devices and existing protocols in a privacy-preserving manner. The third proposed solution transparently collects different "unique" users' data and analyses fingerprints using privacy-preserving codes
Geophysical Study of Gold Mineralized Zones in the Carolina Terrane of South Carolina
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he goal of this study was to calibrate and test geophysical methods for the detection of geological structural and disseminated sulfides in the area of the four largest gold deposits in the Southern Appalachian of South Carolina. The Coastal plain sediments, vegetation and saprolite covering the mining areas remain the most challenging in this region. The work focused on the calibration of high-resolution gravity, and helicopter electromagnetic (EM) and magnetic data provided by OceanaGold over the Haile and Brewer Mines; then calibrating the regional gravity and aeromagnetic data over the four gold mines in South Carolina. Observed geophysical fields are correlated with rock properties: resistivities, susceptibilities and mineral concentrations are measured for 40 samples from 16 drill holes, as well as densities and mineral concentrations for 49,183 samples from 448 drill holes in the Haile ore zone. While high resolution potential field data (gravity and magnetics) has not been proven to be effective at small scales in exploration for disseminated sulfides, there is a strong regional correlation between high amplitude gravity and magnetic anomalies and the most productive gold mines in the Carolina terrane. Helicopter EM methods have been shown to be effective in distinguishing sedimentary from volcanic-dominated sediments in the metamorphic rocks of the Carolina terrane. The interpretation of the gravity and magnetic data utilized tilt derivatives, vertical derivative, reduced to pole anomalies (RTP), shaded relief, frequency spectrum, 3-D Euler deconvolution, core drilling and 2-D forward modeling. The most surprising result was that over the Haile Mine, the residual gravity vi anomalies, tilt derivatives, and vertical derivative show positive anomalies correlated with the location of a disseminated ore body. The gravity field over the ore body can be interpreted as produced by 4% pyrite and molybdenite. Electromagnetic (EM) anomalies are spatially associated with the Haile ore bodies. The edges of a granite pluton are clearly illuminated by the shaded relief, tilt derivative, and Euler deconvolution of the potential fields. The magnetic fields do not show correlations with the mineralized zones but are instead dominated by granitic and gabbro plutons and northwest trending diabase dikes. The integration and interpretation of the results indicate that metamorphism and hydrothermal alteration destroy magnetite and cause demagnetisation anomalies for the Carolina terrane. East-northeast trending linear anomalies have been sampled and dated as Alleghanian lamprophyre dikes providing the first magnetic map of these intrusions at Haile. Finally, we calculated the probability of detecting a geophysical anomaly of the required minimum dimensions with a given survey spacing over the Haile mine area to reduce the risk of missing the target anomaly
Moving from evaluation to trial: how do SMEs start adopting cloud ERP?
The advent of cloud technology involving low subscription overheads cost has provided small and medium-sized enterprises (SMEs) with the opportunity to adopt new cloud-based corporate-wide systems (i.e., cloud ERP). This technology, operating through subscriptionbased services, has now provided SMEs with a complete range of IT applications that were once restricted to large organisations. As anecdotal evidences suggest, SMEs are increasingly adopting cloud-based ERP software. The selection of an ERP is a complex process involving multiple stages and stakeholders, suggesting the importance of closer examination of cloud ERP adoption in SMEs. Yet, prior studies have predominantly treated technology adoption as a single activity and largely ignored the issue of ERP adoption in SMEs. Understanding of the process nature of the adoption and the factors that are important in each stage of the adoption potentially may result in guiding SMEs to make well-informed decisions throughout the ERP selection process. Thus, our study proposes that the adoption of cloud ERP should be examined as a multi-stage process. Using the theory of planned behaviour (TPB) and Ettlie’s adoption stages, as well as employing data gathered from 162 owners of SMEs, our findings show that the factors that influence the intention to adopt cloud ERP vary significantly across adoptive stages
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In vitro fermentation of gum acacia - impact on the faecal microbiota
Interest in the consumption of gum acacia (GA) has been associated with beneficial health effects, which may be mediated in part by prebiotic activity. Two doses of GA and fructooligosaccharide (FOS) (1 and 2%) were tested for their efficacy over 48 h in pH- and temperature-controlled anaerobic batch cultures inoculated with human faeces. Samples were taken after 0, 5, 10, 24 and 48 h of fermentation. The selective effects of GA (increases in Bifidobacterium spp. and Lactobacillus spp.) were similar to those of the known prebiotic FOS. The 1% dose of substrates showed more enhanced selectivity compared to the 2% dose. The fermentation of GA also led to SCFA production, specifically increased acetate after 10, 24 and 48 h of fermentation, propionate after 48 h and butyrate after 24 and 48 h. In addition, FOS led to significant increase in the main SCFAs. These results suggest that GA displays potential prebiotic properties
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