When the Hammer Meets the Nail: Multi-Server PIR for Database-Driven CRN with Location Privacy Assurance

We show that it is possible to achieve information theoretic location privacy for secondary users (SUs) in database-driven cognitive radio networks (CRNs) with an end-to-end delay less than a second, which is significantly better than that of the existing alternatives offering only a computational privacy. This is achieved based on a keen observation that, by the requirement of Federal Communications Commission (FCC), all certified spectrum databases synchronize their records. Hence, the same copy of spectrum database is available through multiple (distinct) providers. We harness the synergy between multi-server private information retrieval (PIR) and database- driven CRN architecture to offer an optimal level of privacy with high efficiency by exploiting this observation. We demonstrated, analytically and experimentally with deployments on actual cloud systems that, our adaptations of multi-server PIR outperform that of the (currently) fastest single-server PIR by a magnitude of times with information theoretic security, collusion resiliency, and fault-tolerance features. Our analysis indicates that multi-server PIR is an ideal cryptographic tool to provide location privacy in database-driven CRNs, in which the requirement of replicated databases is a natural part of the system architecture, and therefore SUs can enjoy all advantages of multi-server PIR without any additional architectural and deployment costs.Comment: 10 pages, double colum

A new kinetic model for cotton reactive dyeing at different temperatures

Reactive dyeing kinetic on cotton at different temperatures has been studied. The dyeing experiments are carried out using liquor-to-materials ratio of 40:1 in a sealed stainless steel dyebath housed on the Ahiba Nuance Speed. A new kinetic model is proposed that describes the dye exhaustion at different durations. This mathematical equation is used to interpret the experimental data in terms of kinetic parameters of the dye molecules. The results show that the theoretical predictions are in reasonable agreement with experimental data with higher average regression coefficients. It is also observed that the exhaustion process of reactive dye in cotton fabrics could be divided into two steps, viz rapid and slow processes

Capillary rise kinetics on woven fabrics – Experimental and theoretical studies

Kinetics study of vertical water capillary rise on woven fabrics has been studied. Experiments are performed at 20±2°C and 65±2% RH by using a CCD camera and an electronic microbalance. A mathematical model is developed in order to interpret the experimental data in terms of diffusion parameters of water molecules on the porous materials and the height attained at equilibrium. The results show that the theoretical predictions are in reasonable agreement with experimental data with higher correlation coefficients. It is also found that kinetic parameters and the height of water attained at equilibrium are influenced by the composition (type of fibre) and the structure of the woven fabrics. It is concluded that the wicking ability is strongly enhanced with the decrease of the weft count (yarns/cm) and in the presence of higher float length of the weft yarns in the woven structure as in the case of satin 8/5. The sorption ability of the cotton fabrics has also been studied by using measurements of the mass of water absorbed by the textile. The results indicate that the satin structure, which is the less tightened one, has the best sorption ability

Use of glucose as an ecofriendly reducing sugar in the application of sulphur dyes -Comparative study with traditional reducing agent

Attempts have been made to replace the mostly used reducing agent (sodium sulphide), and the most effective reducing agent (sodium dithionite), with an environment- friendly reducing sugar (glucose). This comparison is based on the redox potential and pH used under different concentrations of reducing agent, caustic soda and sodium carbonate. The dyeing performance resulting from the reduction of the CI Leuco Sulphur dye Black 1 by each one of the studied reducing agents is appreciated by measuring the colour yield and by evaluating dyeing fastness. The obtained results show that glucose can offer an environmentally safe alternative to sodium dithionite and sodium sulphide as a reducing agent in sulphur dyeing processes