Base station's location privacy in a wireless sensor network (WSN) is critical for information security and operational availability of the network. A key part of securing the base station from potential compromise is to secure the information about its physical location. This paper proposes a technique called base station location privacy via software-defined networking (SDN) in wireless sensor networks (BSLPSDN). The inspiration comes from the architecture of SDN, where the control plane is separated from the data plane, and where control plane decides the policy for the data plane. BSLPSDN uses three categories of nodes, namely, a main controller to instruct the overall operations, a dedicated node to buffer and forward data, and lastly, a common node to sense and forward the packet. We employ three kinds of nodes to collaborate and achieve stealth for the base station and thus protecting it against the traffic-analysis attacks. Different traits of the WSN including energy status and traffic density can actively be monitored by BSLPSDN, which positively affects the energy goals, expected life of the network, load on common nodes, and the possibility of creating diversion in the wake of an attack on the base station. We incorporated multiple experiments to analyze and evaluate the performance of our proposed algorithm. We use single controller with multiple sensor nodes and multiple controllers with multiple sensor nodes to show the level of anonymity of BS. Experiments show that providing BS anonymity via multiple controllers is the best method both in terms of energy and privacy. 相似文献
In communication industry one of the most rapidly growing area is wireless technology and its applications. The efficient access to radio spectrum is a requirement to make this communication feasible for the users that are running multimedia applications and establishing real-time connections on an already overcrowded spectrum. In recent times cognitive radios (CR) are becoming the prime candidates for improved utilization of available spectrum. The unlicensed secondary users share the spectrum with primary licensed user in such manners that the interference at the primary user does not increase from a predefined threshold. In this paper, we propose an algorithm to address the power control problem for CR networks. The proposed solution models the wireless system with a non-cooperative game, in which each player maximize its utility in a competitive environment. The simulation results shows that the proposed algorithm improves the performance of the network in terms of high SINR and low power consumption.
For space-times in general relativity, the Petrov classification of the Weyl conformai curvature and the Plebaski or Segre classification of the Ricci tensor each depend on the properties of the roots of quartic equations. The coefficients in these quartic equations are in general complicated functions of the space-time coordinates. We review the general theory of quartic equations, and discuss algorithms for determining the existence and values of multiple roots. We consider practical implementation of an algorithm and the consequent Petrov classification. Tests of programs embodying this algorithm, using the computer algebra system CLASSI based on SHEEP, are reported. 相似文献
The [FeIV(O)(Me3NTB)]2+ (Me3NTB=tris[(1-methyl-benzimidazol-2-yl)methyl]amine) complex 1 has been shown by Mössbauer spectroscopy to have an S=1 ground state at 4 K, but is proposed to become an S=2 trigonal-bipyramidal species at higher temperatures based on a DFT model to rationalize its very high C−H bond-cleavage reactivity. In this work, 1H NMR spectroscopy was used to determine that 1 does not have C3-symmetry in solution and is not an S=2 species. Our results show that 1 is unique among nonheme FeIV=O complexes in retaining its S=1 spin state and high reactivity at 193 K, providing evidence that S=1 FeIV=O complexes can be as reactive as their S=2 counterparts. This result emphasizes the need to identify factors besides the ground spin state of the FeIV=O center to rationalize nonheme oxoiron(IV) reactivity. 相似文献
Journal of Thermal Analysis and Calorimetry - The significant bioconvection phenomenon with the utilization of nanoparticles encountered fundamental industrial and technological applications in... 相似文献
New tetraalkylaminophosphonium chlorides were readily prepared by four-fold condensation of commercially available [P(CH2OH)4]Cl with a range of fifteen aryl based primary amines, in EtOH, at ambient temperature. All compounds have been characterized by FT–IR spectroscopy and elemental analysis. Solution 31P{1H} NMR studies of these chloride salts reveal their instability with respect to various PIII/PV species. The structures of three examples have been determined by single crystal X-ray diffraction and confirm the pseudotetrahedral arrangement around the PV center. Extensive N–H···Cl hydrogen bonding is observed. 相似文献
Nanoparticles of ferrites (Fe3O4, NiFe2O4, CuFe2O4, and MnFe2O4) were prepared by a reverse (water/oil) microemulsion method. The microemulsion system consisted of cetyltrimethylammonium bromide, 1-butanol, cyclohexane, and a metal salt solution. The procedure was carried out using aqueous ammonia as the coprecipitating agent. Nanosized particles were characterized by thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and pyridine adsorption. The NiFe2O4 sample exhibited narrow mesoporous pore size distribution and high surface area ≈233 m2/g. It achieved good adsorption activity towards the dibenzothiophene (DBT) compound (166.3 μmol/g of DBT adsorbent). The structural properties obtained were very interesting for potential applications in the desulfurization process in petroleum refining. 相似文献
Hierarchical semicrystalline block copolymer nanoparticles are produced in a segmented gas‐liquid microfluidic reactor with top‐down control of multiscale structural features, including nanoparticle morphologies, sizes, and internal crystallinities. Control of multiscale structure on disparate length scales by a single control variable (flow rate) enables tailoring of drug delivery nanoparticle function including release rates.
Marine feed ingredients derived from cephalopods (e.g., squid) and crustaceans (e.g., krill) are commercially used to improve the palatability of shrimp diets. Increase in global demand for shrimps has resulted in overfishing of these marine organisms and is a matter of concern. Insect protein hydrolysate could be a sustainable alternative for the possible replacement of these marine feed ingredients. During this study, four formulations: diet A (control: not containing any palatability enhancer), diet B (containing squid meal and krill oil), diet C (containing 1% insect protein hydrolysate), and diet D (containing 2% insect protein hydrolysate) were tested for (1) time required by first subject to begin feeding (time to strike) and (2) palatability in Litopenaeus vannamei. Additionally, the chemical composition of all four diet formulations was also analyzed. Results indicate that all diets had similar crude composition. The major essential amino acids in all diets were leucine and lysine, whereas eicosapentaenoic acid was the major omega-3 fatty acid in all diets. There were no significant differences between the mean time to strike for all the tested formulations. Palatability of tested formulations was found in the following order: diet D > diet C > diet B = diet A (p < 0.05), indicating that addition of squid meal and krill oil has no effect on palatability in comparison to control, whereas inclusion of insect protein hydrolysates significantly improves the palatability of formulations. Palatability enhancement potential of insect protein hydrolysate could be attributed to the high free amino acid content and water solubility in comparison to squid meal. 相似文献