18 research outputs found

    VAL: Volume and Access Pattern Leakage-Abuse Attack with Leaked Documents

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    Searchable Encryption schemes provide secure search over encrypted databases while allowing admitted information leakages. Generally, the leakages can be categorized into access and volume pattern. In most existing SE schemes, these leakages are caused by practical designs but are considered an acceptable price to achieve high search efficiency. Recent attacks have shown that such leakages could be easily exploited to retrieve the underlying keywords for search queries. Under the umbrella of attacking SE, we design a new Volume and Access Pattern Leakage-Abuse Attack (VAL-Attack) that improves the matching technique of LEAP (CCS ’21) and exploits both the access and volume patterns. Our proposed attack only leverages leaked documents and the keywords present in those documents as auxiliary knowledge and can effectively retrieve document and keyword matches from leaked data. Furthermore, the recovery performs without false positives. We further compare VAL-Attack with two recent well-defined attacks on several real-world datasets to highlight the effectiveness of our attack and present the performance under popular countermeasures.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit

    Safety-oriented planning of expressway truck service areas based on driver demand

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    The rapid development of the economy has promoted the growth of freight transportation. The truck service areas on expressways, as the main places for truck drivers to rest, play an important role in ensuring the driving safety of trucks. If these service areas are constructed densely or provide a plentiful supply of parking areas, they are costly to construct. However, if the distance between two adjacent truck service areas is very large or the number of truck parking spaces in service areas is small, the supply will fail to meet the parking needs of truck drivers. In this situation, the continuous working time of truck drivers will be longer, and this is likely to cause driver fatigue and even traffic accidents. To address these issues, this paper established a non-linear optimization model for truck service area planning of expressways to optimize truck driving safety. An improved genetic algorithm is proposed to solve the model. A case study of a 215.5-kilometers-length section of the Guang-Kun expressway in China was used to demonstrate the effectiveness of the model and algorithm. As validated by this specific case, the proposed model and solution algorithm can provide an optimal plan for the layout of truck service areas that meet the parking needs of truck drivers while minimizing the service loss rate. The research results of this paper can contribute to the construction of truck service areas and the parking management of trucks on expressways.Civil Engineering and Geoscience

    The effects of graphene stacking on the performance of methane sensor: A first-principles study on the adsorption, band gap and doping of graphene

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    The effects of graphene stacking are investigated by comparing the results of methane adsorption energy, electronic performance, and the doping feasibility of five dopants (i.e., B, N, Al, Si, and P) via first-principles theory. Both zigzag and armchair graphenes are considered. It is found that the zigzag graphene with Bernal stacking has the largest adsorption energy on methane, while the armchair graphene with Order stacking is opposite. In addition, both the Order and Bernal stacked graphenes possess a positive linear relationship between adsorption energy and layer number. Furthermore, they always have larger adsorption energy in zigzag graphene. For electronic properties, the results show that the stacking effects on band gap are significant, but it does not cause big changes to band structure and density of states. In the comparison of distance, the average interlamellar spacing of the Order stacked graphene is the largest. Moreover, the adsorption effect is the result of the interactions between graphene and methane combined with the change of graphene’s structure. Lastly, the armchair graphene with Order stacking possesses the lowest formation energy in these five dopants. It could be the best choice for doping to improve the methane adsorption.Electronic Components, Technology and Material

    Antennas for base stations in wireless communications / Zhi Ning Chen, Kwai-Man Luk.

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    Includes bibliographical references and index.xxvi, 372 pages :Design antennas for modern wireless communications systems. Written by a global team of expert contributors, this book offers complete details on the wide range of antennas used in today's wireless communication networks. Coverage includes the most popular applications in WWAN (GSM, CDMA, and WCDMA), WLAN (Bluetooth and WiFi), WMAN (WiMAX), and WPAN (UWB and RFID). Antennas for Base Stations in Wireless Communications presents a full picture of modern base station antenna technology--from fundamentals and parameters to engineering and advanced solutions--and highlights new technologies in antenna design with enhanced performance. Real-world case studies provide you with practical examples that can be applied to your own system designs. - Publisher.

    Hybrid Plasmonics Slot THz Waveguide for Subwavelength Field Confinement and Crosstalk between Two Waveguides

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    The slot waveguide has attracted considerable attention because of its ability to confine and guide electromagnetic energy at the subwavelength scale beyond the diffraction limit. We propose a novel terahertz slot waveguide structure to achieve a better tradeoff between propagation length and field confinement capacity, the novel waveguide consisting of a two slot structure. The performances of terahertz waveguides were investigated using the finite-element method. The results demonstrated that the hybrid slot waveguide (HSW) provides significantly enhanced field confinement in low index slot regions: more than five times that of traditional low index slot waveguides (LISWs). An optimized HSW structure was achieved by tuning the tradeoff between mode confinement and propagation length. We also showed that its integration in conventional planar waveguide circuits was greatly improved compared with the LISWs, by comparing their crosstalk. The proposed new HSW structure has great potential to enable THz production of compact integration and could lead to true semiconductor-basedTHz applications with high performance.Electronic Components, Technology and Material

    A CMOS-Compatible Hybrid Plasmonic Slot Waveguide With Enhanced Field Confinement

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    The emerging field of nanophotonics requires plasmonic devices to be fully compatible with semiconductor fabrication techniques. However, very few feasible practical structures exist at present. Here, we propose a CMOS-compatible hybrid plasmonic slot waveguide (HPSW) with enhanced field confinement. Our simulation results show that the HPSW exhibits significantly enhanced field confinement as compared with the traditional low-index slot waveguides and the hybrid metal dielectric slot waveguides. By controlling the thicknesses of different layers, an optimized HPSW structure with a better tradeoff between field confinement and propagation length has been simultaneously achieved.Electronic Components, Technology and Material

    A Series of Ternary Metal Chloride Superionic Conductors for High-Performance All-Solid-State Lithium Batteries

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    Understanding the relationship between structure, ionic conductivity, and synthesis is the key to the development of superionic conductors. Here, a series of Li3-3xM1+xCl6 (−0.14 < x ≤ 0.5, M = Tb, Dy, Ho, Y, Er, Tm) solid electrolytes with orthorhombic and trigonal structures are reported. The orthorhombic phase of Li–M–Cl shows an approximately one order of magnitude increase in ionic conductivities when compared to their trigonal phase. Using the Li–Ho–Cl components as an example, their structures, phase transition, ionic conductivity, and electrochemical stability are studied. Molecular dynamics simulations reveal the facile diffusion in the z-direction in the orthorhombic structure, rationalizing the improved ionic conductivities. All-solid-state batteries of NMC811/Li2.73Ho1.09Cl6/In demonstrate excellent electrochemical performance at both 25 and −10 °C. As relevant to the vast number of isostructural halide electrolytes, the present structure control strategy guides the design of halide superionic conductors.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.RST/Storage of Electrochemical EnergyPhotovoltaic Materials and DevicesRID/TS/Instrumenten groe

    Nitrous oxide fluxes from the littoral zone of a lake on the Qinghai-Tibetan Plateau

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    Nitrous oxide (N(2)O) fluxes were measured in six littoral mirco-zones of Lake Huahu on Qinghai-Tibetan Plateau in the peak growing season of years of 2006 and 2007. The weighted mean N(2)O flux rate was 0.08 mg N m (-aEuro parts per thousand 2) h (-aEuro parts per thousand 1) (ranged from -0.07 to 0.35 mg N m (-aEuro parts per thousand 2) h (-aEuro parts per thousand 1)). The result was relatively high in the scope of N(2)O fluxes from boreal and temperate lakes. Emergent plant zones (Hippuris vulgaris and Glyceria maxima stands) recorded the highest N(2)O flux rate (0.11 +/- 0.24 and 0.08 +/- 0.17 mg N m (-aEuro parts per thousand 2) h (-aEuro parts per thousand 1), respectively). Non-vegetated lakeshore recorded the lowest N(2)O flux (0.03 +/- 0.11 mg N m (-aEuro parts per thousand 2) h (-aEuro parts per thousand 1)), lower than that from the floating mat zone of Carex muliensis (0.05 +/- 0.18 mg N m (-aEuro parts per thousand 2) h (-aEuro parts per thousand 1)), the floating-leaved plant zone of Polygonum amphibium (0.07 +/- 0.11 mg N m (-aEuro parts per thousand 2) h (-aEuro parts per thousand 1)), and the wet meadow (0.07 +/- 0.15 mg N m (-aEuro parts per thousand 2) h (-aEuro parts per thousand 1)). Standing water depths were important factors to explain such spatial variations in N(2)O fluxes. Significant temporal variations in N(2)O fluxes were also found. Such temporal variation in N(2)O flux in the littoral zone may be dependent on the interaction of water regime and thermal conditions, instead of the latter solely. These results showed the importance of the littoral zone of lake, especially the emergent plant zone, as a hotspot of N(2)O fluxes in such grazing meadows
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