SGXIO: Generic Trusted I/O Path for Intel SGX

Application security traditionally strongly relies upon security of the underlying operating system. However, operating systems often fall victim to software attacks, compromising security of applications as well. To overcome this dependency, Intel introduced SGX, which allows to protect application code against a subverted or malicious OS by running it in a hardware-protected enclave. However, SGX lacks support for generic trusted I/O paths to protect user input and output between enclaves and I/O devices. This work presents SGXIO, a generic trusted path architecture for SGX, allowing user applications to run securely on top of an untrusted OS, while at the same time supporting trusted paths to generic I/O devices. To achieve this, SGXIO combines the benefits of SGX's easy programming model with traditional hypervisor-based trusted path architectures. Moreover, SGXIO can tweak insecure debug enclaves to behave like secure production enclaves. SGXIO surpasses traditional use cases in cloud computing and makes SGX technology usable for protecting user-centric, local applications against kernel-level keyloggers and likewise. It is compatible to unmodified operating systems and works on a modern commodity notebook out of the box. Hence, SGXIO is particularly promising for the broad x86 community to which SGX is readily available.Comment: To appear in CODASPY'1

Genetic Fusions of a CFA/I/II/IV MEFA (Multiepitope Fusion Antigen) and a Toxoid Fusion of Heat-Stable Toxin (STa) and Heat-Labile Toxin (LT) of Enterotoxigenic Escherichia coli (ETEC) Retain Broad Anti-CFA and Antitoxin Antigenicity

Citation: Ruan, X. S., Sack, D. A., & Zhang, W. P. (2015). Genetic Fusions of a CFA/I/II/IV MEFA (Multiepitope Fusion Antigen) and a Toxoid Fusion of Heat-Stable Toxin (STa) and Heat-Labile Toxin (LT) of Enterotoxigenic Escherichia coli (ETEC) Retain Broad Anti-CFA and Antitoxin Antigenicity. Plos One, 10(3), 20. doi:10.1371/journal.pone.0121623Immunological heterogeneity has long been the major challenge in developing broadly effective vaccines to protect humans and animals against bacterial and viral infections. Enterotoxigenic Escherichia coli (ETEC) strains, the leading bacterial cause of diarrhea in humans, express at least 23 immunologically different colonization factor antigens (CFAs) and two distinct enterotoxins [heat-labile toxin (LT) and heat-stable toxin type Ib (STa or hSTa)]. ETEC strains expressing any one or two CFAs and either toxin cause diarrhea, therefore vaccines inducing broad immunity against a majority of CFAs, if not all, and both toxins are expected to be effective against ETEC. In this study, we applied the multiepitope fusion antigen (MEFA) strategy to construct ETEC antigens and examined antigens for broad anti-CFA and antitoxin immunogenicity. CFA MEFA CFA/I/II/IV [CVI 2014, 21(2): 2439], which carried epitopes of seven CFAs [CFA/I, CFA/II (CS1, CS2, CS3), CFA/IV (CS4, CS5, CS6)] expressed by the most prevalent and virulent ETEC strains, was genetically fused to LT-STa toxoid fusion monomer 3xSTa(A14Q)-dmLT or 3xSTa(N12S)-dmLT [IAI 2014, 82(5): 1823-32] for CFA/I/II/IV-STaA14Q-dmLT and CFA/I/II/IV-STaN12S-dmLT MEFAs. Mice intraperitoneally immunized with either CFA/I/II/IV-STa-(toxoid)-dmLT MEFA developed antibodies specific to seven CFAs and both toxins, at levels equivalent or comparable to those induced from co-administration of the CFA/I/II/IV MEFA and toxoid fusion 3xSTaN12S-dmLT. Moreover, induced antibodies showed in vitro adherence inhibition activities against ETEC or E. coli strains expressing these seven CFAs and neutralization activities against both toxins. These results indicated CFA/I/II/IV-STa-(toxoid)-dmLT MEFA or CFA/I/II/IV MEFA combined with 3xSTa(N12S)-dmLT induced broadly protective anti-CFA and antitoxin immunity, suggested their potential application in broadly effective ETEC vaccine development. This MEFA strategy may be generally used in multivalent vaccine development

Composite-fermion crystallites in quantum dots

The correlations in the ground state of interacting electrons in a two-dimensional quantum dot in a high magnetic field are known to undergo a qualitative change from liquid-like to crystal-like as the total angular momentum becomes large. We show that the composite-fermion theory provides an excellent account of the states in both regimes. The quantum mechanical formation of composite fermions with a large number of attached vortices automatically generates omposite fermion crystallites in finite quantum dots.Comment: 5 pages, 3 figure

Utilising a systematic knowledge management based system to optimise project management operations in oil and gas organisations

Purpose: This research examined the efficacy of knowledge management based systems and best practices that could be used to address operational issues in the oil and gas sector. Design/methodology/approach: Given little was known empirically about the strategies and practices which contribute to improved performance, innovation and continuous improvement in the oil and gas sector qualitative method was used. Semi-structured interviews were used to derive senior managers’ constructs of project delivery efficiency and knowledge management based systems. The interviews were analysed through the use of a qualitative analysis software package NUDIST NVivoTM. Participants were selected using purposive sampling. Validity and reliability were achieved by first assessing the plausibility in terms of already existing knowledge on some of the operational issues raised by participants. Findings: These were synthesised into a framework capturing seven-well defined stages. All these steps emerged as being related; they are comprised of independent variables. These steps were found to comprise of knowledge management technology approaches, knowledge management people approaches, knowledge management strategies and value enhancing practices. Research limitations/implications: Although the findings are pertinent to oil and gas organisations, it will be important to conduct follow-up research validating the potential for using the results of this study to establish frameworks for knowledge and information management in different organisations and contexts. This will provide not only data about the validity of the framework in generic terms but will also generate additional data on the application of knowledge management strategy. Practical implications: As shown in this study, successful knowledge management based systems requires the aligning of business strategy, technology for knowledge management, project management operations with an enterprise-knowledge sharing culture. Such sharing requires managing the behaviour of project personnel such that knowledge transfer becomes part of the organisation’s norm. Social implications: The implementation of knowledge management based systems requires deliberate planning and action to create the conditions for success and put in place the strategy, leadership, goals, process, skills, systems, issue resolution, and structure to direct and exploit the dynamic nature of project work. The strategies proposed in this research cannot be expected to resolve all knowledge management issues in the oil and gas sector. However, their use defines an approach that is superior to the traditional approaches typically adopted and consequently merits far wider application. Originality/value: The proposed framework presents a better way of optimising the performance of project-based operations thus enabling oil and gas organisations to reform their poor performance on projects and empower them to better manage emerging cultural challenges in their future projects. Reflecting on their experiences, the participants confirmed that the proposed knowledge management framework and its seven well-defined stages were central to the effectiveness of knowledge management in oil and gas operations. Although the scope of this research was restricted to projects in Nigeria and the UK, the geographical focus of this research does not invalidate these results with respect to other countries. The fact is that the oil and gas sector globally shares some common fundamental characteristics

Prospects of cold dark matter searches with an ultra-low-energy germanium detector

The report describes the research program on the development of ultra-low-energy germanium detectors, with emphasis on WIMP dark matter searches. A threshold of 100 eV is achieved with a 20 g detector array, providing a unique probe to the low-mas WIMP. Present data at a surface laboratory is expected to give rise to comparable sensitivities with the existing limits at the $\rm{5 - 10 GeV}$ WIMP-mass range. The projected parameter space to be probed with a full-scale, kilogram mass-range experiment is presented. Such a detector would also allow the studies of neutrino-nucleus coherent scattering and neutrino magnetic moments.Comment: 3 pages, 4 figures, Proceedings of TAUP-2007 Conferenc

Lithospheric Structure and Tectonic Processes Constrained by Microearthquake Activity at the Central Ultraslow-Spreading Southwest Indian Ridge (49.2° to 50.8°E)

Beneath ultra‐slow spreading ridges, the oceanic lithosphere remains poorly understood. Using recordings from a temporary array of ocean bottom seismometers, we here report a ~17‐days‐long microearthquake study on two segments (27 and 28) of the ultra‐slow spreading Southwest Indian Ridge (49.2° to 50.8° E). A total of 214 locatable microearthquakes are recorded; seismic activity appears to be concentrated within the west median valley at segment 28 and adjacent nontransform discontinuities (NTDs). Earthquakes reach a maximum depth of ~20 km beneath the seafloor, and they mainly occur in the mantle, implying a cold and thick brittle lithosphere. The relatively uniform brittle/ductile boundary beneath segment 28 suggests that there is no focused melting in this region. The majority of earthquakes are located below the Moho interface, and a 5‐km‐thick aseismic zone is present beneath segment 28 and adjacent NTDs. At the Dragon Flag hydrothermal vent field along segment 28, the presence of a detachment fault has been inferred from geomorphic features and seismic tomography. Our seismicity data show that this detachment fault deeply penetrates into the mantle with a steeply dipping (~65°) interface, and it appears to rotate to a lower angle in the upper crust, with ~55° of rollover. There is a virtual seismic gap beneath magmatic segment 27, which may be connected to the presence of an axial magma chamber beneath the spreading centre as well as focused melting; in this scenario, the increased magma supply produces a broad, elevated temperature environment which suppresses earthquake generation

Effect of electron-electron scattering on spin dephasing in a high-mobility low-density twodimensional electron gas

Utilizing time-resolved Kerr rotation techniques, we have investigated the spin dynamics of a high mobility, low density two dimensional electron gas in a GaAs/Al0:35Ga0:65As heterostructure in dependence on temperature from 1.5 K to 30 K. It is found that the spin relaxation/dephasing time under a magnetic field of 0.5 T exhibits a maximum of 3.12 ns around 14 K, superimposed on an increasing background with rising temperature. The appearance of the maximum is ascribed to that at the temperature where the crossover from the degenerate to the nondegenerate regime takes place, electron-electron Coulomb scattering becomes strongest, and thus inhomogeneous precession broadening due to D'yakonov-Perel'(DP) mechanism becomes weakest. These results agree with the recent theoretical predictions [Zhou et al., PRB 75, 045305 (2007)], verifying the importance of electron-electron Coulomb scattering to electron spin relaxation/dephasing.Comment: 4 pages, 2 figure

Bandgap properties of two-dimensional low-index photonic crystals

We study the bandgap properties of two-dimensional photonic crystals created by a lattice of rods or holes conformed in a symmetric or asymmetric triangular structure. Using the plane-wave analysis, we calculate a minimum value of the refractive index contrast for opening both partial and full two-dimensional spectral gaps for both TM and TE polarized waves. We also analyze the effect of ellipticity of rods and holes and their orientation on the threshold value and the relative size of the bandgap.Comment: 5 pages, 6 figures, App. Phys. B. styl