Tuning a two-round group key agreement

In 2007, Bohli et al. (Int J Inf Secur 6:243–254, 2007) proposed a two-round group key agreement protocol in the random oracle model, which in addition to semantic security offers strong entity authentication and a security guarantee against malicious insiders. We suggest a modification of this protocol that preserves the security guarantees and the round complexity, but reduces the amount of data that has to be sent and also reduces the number of signature computations and verifications by 50 %. Moreover, we propose a variant of Bohli et al.’s protocol whose security analysis does not require a random oracle or other idealizing assumptions.     

α-Tocopherol alteration of soybean antiherbivory toTrichoplusia ni larvae

The antioxidant vitamin E, -tocopherol, was tested as a candidate elicitor of alterable antiherbivory in soybean plants against cabbage looper larvae. Although a nonspecific antioxidant, vitamin E proved elicitory to the involved sulfhydryl-dependent receptor-energy transducer protein in soybean plasma membrane. Effects of -tocopherol were dependent on dosage, time, and space in the plant. The observed elicited effects were all decreases in herbivory. The best negative phytochemical correlate of looper feeding was the percentage of increased total HPLC peak area of extractables from elicited as compared to nonelicited leaves. Some specific compounds, e.g., glyceollins, were quantitatively major components of the total profile of secondary metabolites.     

Near infrared light-induced disassembly of polymeric micelles based on methylene blue conjugated polyethylene glycol

Light-sensitive drug delivery systems are considered ideal for applications in the biomedical fields for their ability to release the payload in an on-demand spatiotemporal controlled manner through the manipulation of the light source. Among the broad radiation spectrum, near infrared (NIR) light is considered advantageous compared to UV and visible light, due to its inherently lower photodamage to normal tissues and deeper penetration to lesion areas. In this study, we report a successful synthesis of a polymer capable of undergoing partial degradation upon irradiation with NIR light by conjugating 10-N-carbamoyl linkage methylene blue (MB) moiety, a NIR photocleavable ligand, with polyethylene glycol (PEG). Through effective coupling of MB, a hydrophobic moiety, to the hydrophilic PEG molecule, an amphiphilic polymer was synthesized, as demonstrated by a lowered surface tension (55 mN/m at 0.1% wt/vol). Subsequently, photo-induced reversal of surface activity associated with self-assembled structure disruption, was displayed by surface tension measurements, size distribution analysis, and burst release profile of paclitaxel (PTX) from polymeric micelles upon the exposure to NIR irradiation.     

Comprehensive Automation for Specialty Crops: Year 1 results and lessons learned

Comprehensive Automation for Specialty Crops is a project focused on the needs of the specialty crops sector, with a focus on apples and nursery trees. The project’s main thrusts are the integration of robotics technology and plant science; understanding and overcoming socio-economic barriers to technology adoption; and making the results available to growers and stakeholders through a nationwide outreach program. In this article, we present the results obtained and lessons learned in the first year of the project with a reconfigurable mobility infrastructure for autonomous farm driving. We then present sensor systems developed to enable three real-world agricultural applications—insect monitoring, crop load scouting, and caliper measurement—and discuss how they can be deployed autonomously to yield increased production efficiency and reduced labor costs.     

Autonomous landing at unprepared sites by a full-scale helicopter

Helicopters are valuable since they can land at unprepared sites; however, current unmanned helicopters are unable to select or validate landing zones (LZs) and approach paths. For operation in unknown terrain it is necessary to assess the safety of a LZ. In this paper, we describe a lidar-based perception system that enables a full-scale autonomous helicopter to identify and land in previously unmapped terrain with no human input.We describe the problem, real-time algorithms, perception hardware, and results. Our approach has extended the state of the art in terrain assessment by incorporating not only plane fitting, but by also considering factors such as terrain/skid interaction, rotor and tail clearance, wind direction, clear approach/abort paths, and ground paths.In results from urban and natural environments we were able to successfully classify LZs from point cloud maps. We also present results from 8 successful landing experiments with varying ground clutter and approach directions. The helicopter selected its own landing site, approaches, and then proceeds to land. To our knowledge, these experiments were the first demonstration of a full-scale autonomous helicopter that selected its own landing zones and landed.     

The Effect of Distribution on Product Temperature Profile in Thermally Insulated Containers for Express Shipments

An uninterrupted cold chain is a continual series of storage and distribution activities that maintain a specific temperature or temperature range. Cold chain solutions typically involve excessive packaging to ensure that the desired product temperature is maintained through the distribution process, thereby increasing the logistics‐related costs. There is a myriad of solutions available for shipping temperature‐sensitive products, including those constructed with a variety of packaging materials as well as refrigerants. Although static characteristics for thermally insulated packaging solutions such as the R‐values of package systems as well as the melting points and heat absorption rates of various refrigerants have been studied in the past, none of the past studies have evaluated the effect of comprehensive distribution on the reliability of the cold chain packaging solutions. This research was undertaken to study the temperature profiles for factors such as different densities for a given thickness of thermally insulating material, wall thicknesses and distribution environments for four different types of materials—polyurethane, virgin expanded polystyrene, recycled content expanded polystyrene and vacuum‐insulated panels. The temperature range of 2 °C–8 °C, critical for pharmaceutical drugs and vaccines, was targeted. An interesting regression‐based finding was that the interaction between the R‐value and the wall thickness significantly influenced the length of time the thermally insulated packages stayed in the desired range of 2 °C–8 °C . The findings of this study will be decisive in designing cost‐efficient and practical single‐use cold chain transportation solutions for temperature‐sensitive products. Copyright © 2012 John Wiley & Sons, Ltd.     

Use of cellular confinement for improved railway performance on soft subgrades

Due to extensive right-of-way, railroads are inevitably subject to poor subgrade conditions and interrupted service for significant maintenance due to excessive deformations and loss of track geometry. Geocell confinement presents itself as a possible solution for improving performance of ballasted railroad embankments over weak subgrade. To investigate the efficacy of geocell confinement on ballasted railway embankments, a set of well-instrumented, large-scale cyclic plate loading tests and numerical simulations were performed on geocell-confined ballast overlaying a weak subgrade material. The agreement of results from tests and simulations served as a basis for simulating practical track geometry and performance for various geocell configurations and subgrades using three-dimensional (3D) finite element (FE) analyses. The study showed that geocell reinforcement significantly decreased track settlement, decreased subgrade deformations with lower and uniform distribution of vertical stresses on subgrade and inhibited lateral deformation and serviceability under cyclic loading. These results demonstrate that geocell confinement can be an effective alternative to subsurface improvement or shorter maintenance cycles, particularly on weak subgrades.     

Relative intensities for Li (i = 1-3) and Mi (i = 1-5) subshell X-rays

The intensities for L_i (i = 1-3) subshell X-ray lines have been computed relative to the most intense line in each series, for elements with 30 ? Z ? 92, from published X-ray emission rates based on the Dirac-Fock (DF) model. In the case of M_i (i = 1-5) subshell X-ray lines, complete sets of emission rates based on both the Dirac-Hartree-Slater and the DF models have been generated for elements with 65 ? Z ? 92 by logarithmic interpolation of the data available for a limited number of elements. The intensities for different M X-ray lines have been computed relative to the most intense line in each series using these two sets of emission rates. The L_i (i = 1-3) and M_i (i = 1-5) subshell X-ray relative intensities computed from the DF model based emission rates have been least-squares-fitted to polynomials in the atomic number for use in software packages for quantitative elemental analysis using X-ray emission techniques and for other applications.     

Investigations on surface composition and microstructure of sintered barium titanate

The paper describes studies on surface atomic composition, microstructure and microarea elemental distribution in sintered undoped as well as donor or acceptor doped polycrystalline barium titanate ceramics. The specimens examined are derived from barium titanate powders synthesized by two different wet chemical procedures namely oxalate precursor route and gel-to-crystallite conversion. The compositional analysis is carried out by backscattering spectrometry (BS) involving 3.05 MeV ¹⁶O(α,α)¹⁶O resonant scattering while investigations on microstructure and microarea elemental distribution are performed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The specimens prepared by either method are monophasic; however, their surface atomic composition, microstructural features as well as electrical characteristics are significantly different. The specimens obtained by oxalate precursor route generally have Ti rich surfaces and exhibit coarse to fine grained microstructure depending on the nature and extent of doping. The Mn-doped specimens exhibit appreciable O deficiency. The specimens prepared by gel to crystallite conversion, in contrast, usually have Ba enriched surfaces and exhibit fine-grained microstructure. EDS measurements show the segregation of acceptors such as Mn, Cu and Zn in the grain boundaries of oxalate precursor derived ceramics. Further, the relative atomic ratio of Ti to Ba at the sites of segregations is higher compared to other locations.