ABAKA : a novel attribute-based k-anonymous collaborative solution for LBSs

The increasing use of mobile devices, along with advances in telecommunication systems, increased the popularity of Location-Based Services (LBSs). In LBSs, users share their exact location with a potentially untrusted Location-Based Service Provider (LBSP). In such a scenario, user privacy becomes a major con- cern: the knowledge about user location may lead to her identification as well as a continuous tracing of her position. Researchers proposed several approaches to preserve users’ location privacy. They also showed that hiding the location of an LBS user is not enough to guarantee her privacy, i.e., user’s pro- file attributes or background knowledge of an attacker may reveal the user’s identity. In this paper we propose ABAKA, a novel collaborative approach that provides identity privacy for LBS users considering users’ profile attributes. In particular, our solution guarantees p -sensitive k -anonymity for the user that sends an LBS request to the LBSP. ABAKA computes a cloaked area by collaborative multi-hop forwarding of the LBS query, and using Ciphertext-Policy Attribute-Based Encryption (CP-ABE). We ran a thorough set of experiments to evaluate our solution: the results confirm the feasibility and efficiency of our proposal

केंद्रीय समुद्री मात्स्यिकी अनुसंधान संस्थान का कालीकट अनुसंधान केंद्र

केंद्रीय समुद्री मात्स्यिकी अनुसंधान संस्थान का कालीकट अनुसंधान केंद्

Ab-initio computation of neutron-rich oxygen isotopes

We compute the binding energy of neutron-rich oxygen isotopes and employ the coupled-cluster method and chiral nucleon-nucleon interactions at next-to-next-to-next-to-leading order with two different cutoffs. We obtain rather well-converged results in model spaces consisting of up to 21 oscillator shells. For interactions with a momentum cutoff of 500 MeV, we find that 28O is stable with respect to 24O, while calculations with a momentum cutoff of 600 MeV result in a slightly unbound 28O. The theoretical error estimates due to the omission of the three-nucleon forces and the truncation of excitations beyond three-particle-three-hole clusters indicate that the stability of 28O cannot be ruled out from ab-initio calculations, and that three-nucleon forces and continuum effects play the dominant role in deciding this question.Comment: 5 pages + eps, 3 figure

Record size of (Carrot tongue sole) Cynoglossus dubius, caught off Veraval, Gujarat

The largest ever recorded tongue sole (Cynoglossus dubius) from Indian waters was landed by a monofilament gillnet at Veraval Fishing Harbour in Gujarat

Signature of a silver phase percolation threshold in microscopically phase separated ternary Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses

Temperature modulated Alternating Differential Scanning Calorimetric (ADSC) studies show that Se rich Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses are microscopically phase separated, containing Ag2Se phases embedded in a Ge0.15Se0.85 backbone. With increasing silver concentration, Ag2Se phase percolates in the Ge-Se matrix, with a well-defined percolation threshold at x = 0.10. A signature of this percolation transition is shown up in the thermal behavior, as the appearance of two exothermic crystallization peaks. Density, molar volume and micro-hardness measurements, undertaken in the present study, also strongly support this view of percolation transition. The super-ionic conduction observed earlier in these glasses at higher silver proportions, is likely to be connected with the silver phase percolation.Comment: 4 pages, 7 figure

Magnetic and humidity sensing properties of nanostructured Cu[x]Co[1-x]Fe2O4 synthesized by auto combustion technique

Magnetic nanomaterials (23-43 nm) of Cu$_x$Co$_{1-x}$Fe$_2$O$_4$\ (x = 0.0, 0.5 and 1.0) were synthesized by auto combustion method. The crystallite sizes of these materials were calculated from X-ray diffraction peaks. The band observed in Fourier transform infrared spectrum near 575 cm$^{-1}$ in these samples confirm the presence of ferrite phase. Conductivity measurement shows the thermal hysteresis and demonstrates the knee points at 475$^o$C, 525$^o$C and 500$^o$C for copper ferrite, cobalt ferrite and copper-cobalt mixed ferrite respectively. The hystersis M-H loops for these materials were traced using the Vibrating Sample Magnetometer (VSM) and indicate a significant increase in the saturation magnetization (M$_s$) and remanence (M$_r$) due to the substitution of Cu$^{2+}$ ions in cobalt ferrite, while the intrinsic coercivity (H$_c$) was decreasing. Among these ferrites, copper ferrite exhibits highest sensitivity for humidity.Comment: 12 pages, 7 figure

Nanoindentation studies on waveguides inscribed in chalcogenide glasses using ultrafast laser

Optical straight waveguides are inscribed in GeGaS and GeGaSSb glasses using a high repetition-rate sub-picosecond laser. The mechanical properties of the glasses in the inscribed regions, which have undergone photo induced changes, have been evaluated by using the nanoindentation technique. Results show that the hardness and elastic modulus of the photo-modified glasses are significantly lower as compared to the other locations in the waveguide, which tend to be similar to those of the unexposed areas. The observed mechanical effects are found to correlate well with the optical properties of the waveguides. Further, based on the results, the minimum threshold values of hardness and elastic modulus for the particular propagation mode of the waveguide (single or multi), has been established

Fair and optimistic quantum contract signing

We present a fair and optimistic quantum contract signing protocol between two clients that requires no communication with the third trusted party during the exchange phase. We discuss its fairness and show that it is possible to design such a protocol for which the probability of a dishonest client to cheat becomes negligible, and scales as N^{-1/2}, where N is the number of messages exchanged between the clients. Our protocol is not based on the exchange of signed messages: its fairness is based on the laws of quantum mechanics. Thus, it is abuse-free, and the clients do not have to generate new keys for each message during the Exchange phase. We discuss a real-life scenario when the measurement errors and qubit state corruption due to noisy channels occur and argue that for real, good enough measurement apparatus and transmission channels, our protocol would still be fair. Our protocol could be implemented by today's technology, as it requires in essence the same type of apparatus as the one needed for BB84 cryptographic protocol. Finally, we briefly discuss two alternative versions of the protocol, one that uses only two states (based on B92 protocol) and the other that uses entangled pairs, and show that it is possible to generalize our protocol to an arbitrary number of clients.Comment: 11 pages, 2 figure

Record size of Oriental sole (Euryglossa orientalis) (Bloch & Schneider, 1801), caught off Nawabunder, Gujarat

E. orientalis largest ever recorded oriental sole landed in Nawabunder Fishing Harbour in Gujarat caught by Dol net

Bumper catch of spiny lobsters by trawlers and gill netters at Okha, Gujarat

During the post-monsoon months of September and October in 2007, an estimated 900 t of spiny lobsters Panulirus polyphagus worth of Rs. 67 crores was landed by trawlers and gill netters at Okha and Rupenbander