230 research outputs found
Channel Sounding for the Masses: Low Complexity GNU 802.11b Channel Impulse Response Estimation
New techniques in cross-layer wireless networks are building demand for
ubiquitous channel sounding, that is, the capability to measure channel impulse
response (CIR) with any standard wireless network and node. Towards that goal,
we present a software-defined IEEE 802.11b receiver and CIR estimation system
with little additional computational complexity compared to 802.11b reception
alone. The system implementation, using the universal software radio peripheral
(USRP) and GNU Radio, is described and compared to previous work. By overcoming
computational limitations and performing direct-sequence spread-spectrum
(DS-SS) matched filtering on the USRP, we enable high-quality yet inexpensive
CIR estimation. We validate the channel sounder and present a drive test
campaign which measures hundreds of channels between WiFi access points and an
in-vehicle receiver in urban and suburban areas
Mobility Assisted Secret Key Generation
posterSignature Based Key Generation. Wireless link signature; multiple paths caused by radio waves; their measurements are good signatures of links; link signatures measured almost symmetrically at two ends of wireless link, but cannot be measured from another location; use for secret key establishment; wireless devices sample link signature space in physical area; collect measurements at different unpredictable locations; combine them to produce strong keys
New Graphical Password Scheme Containing Questions-Background-Pattern and Implementation
Security of authentication is needed to be provided superlatively to secure users’ personal and exchange information, since online information exchange systems have been developed according to internet speed. Therefore, aim of the chapter is to develop current graphical password scheme based on recall, create and implement a new graphical password scheme composed of three layer verification. We programmed our scheme in order to use in section of anonymous information exchange system and user’s registration of trading chat room. While we conducted survey on user by accessing participant to our system lied in participants’ local network and we analyzed in accordance with the average length of their created password and statistical significant of entropy bit. From the survey of total participants, our scheme has statistical significance, furthermore it was proved that it can secure form a variety of attacks as entropy bit was high
Electronic Information Major Practice Teaching Reform Concentrated Research and Innovation
AbstractBringing forward the concentration of practical teaching system reform ideas are based on product-oriented, hierarchical progressive. The idea associates all parts of practice, establishing a large framework system. This approach reflects the intrinsic link between knowledge, reached through the practice of teaching will be the focus of a comprehensive knowledge of the purpose. Its implementation will help to change the traditional teaching mode, and to further promote the theory of teaching, thereby raising the overall quality of training
Learning Explicit Contact for Implicit Reconstruction of Hand-held Objects from Monocular Images
Reconstructing hand-held objects from monocular RGB images is an appealing
yet challenging task. In this task, contacts between hands and objects provide
important cues for recovering the 3D geometry of the hand-held objects. Though
recent works have employed implicit functions to achieve impressive progress,
they ignore formulating contacts in their frameworks, which results in
producing less realistic object meshes. In this work, we explore how to model
contacts in an explicit way to benefit the implicit reconstruction of hand-held
objects. Our method consists of two components: explicit contact prediction and
implicit shape reconstruction. In the first part, we propose a new subtask of
directly estimating 3D hand-object contacts from a single image. The part-level
and vertex-level graph-based transformers are cascaded and jointly learned in a
coarse-to-fine manner for more accurate contact probabilities. In the second
part, we introduce a novel method to diffuse estimated contact states from the
hand mesh surface to nearby 3D space and leverage diffused contact
probabilities to construct the implicit neural representation for the
manipulated object. Benefiting from estimating the interaction patterns between
the hand and the object, our method can reconstruct more realistic object
meshes, especially for object parts that are in contact with hands. Extensive
experiments on challenging benchmarks show that the proposed method outperforms
the current state of the arts by a great margin.Comment: 17 pages, 8 figure
Research progress and future prospects of antimicrobial modified polyetheretherketone (PEEK) for the treatment of bone infections
Infection of the bone is a difficult problem in orthopedic diseases. The key and basis of the treatment of bone infection is the effective control of local infection, as well as the elimination of infection focus and dead cavities. The most commonly used approach utilized for the prevention and management of bone infection is the application of antibiotic bone cement. However, the incorporation of antibiotics into the cement matrix has been found to considerably compromise the mechanical characteristics of bone cement. Moreover, some investigations have indicated that the antibiotic release rate of antibiotic bone cement is relatively low. Polyetheretherketone (PEEK) and its composites have been considered to perfectly address the challenges above, according to its favorable biomechanical characteristics and diverse surface functionalizations. This article provides a comprehensive overview of the recent advancements in the antimicrobial modification of PEEK composites in the field of antibacterial therapy of bone infection. Furthermore, the potential application of PEEK-modified materials in clinical treatment was discussed and predicted
Intramuscular vitamin A injection in newborn lambs enhances antioxidant capacity and improves meat quality
IntroductionVitamin A (VA) and its metabolite, retinoic acid (RA) possess several biological functions. This report investigated whether neonatal intramuscular VA injection affected antioxidative activity and meat quality in longissimus dorsi (LD) muscle of lambs.MethodsLambs were injected with 0 (control) or 7,500 IU VA palmitate into the biceps femoris muscle on day 2 after birth. At 3, 12, and 32 weeks of age, blood samples were collected in the jugular vein for serum levels of RA and muscle samples were collected in the biceps femoris for analysis of relative mRNA expression of enzyme contributors to retinoid metabolism. All animals were harvested at 32 weeks of age and muscle samples were collected to explore the role of VA on the meat quality and antioxidant capacity of lambs.Results and discussionOur results indicated that VA increased the redness, crude protein, and crude fat (p < 0.05), without affecting moisture, ash, and amino acid composition in LD muscle (p > 0.05). In addition, VA increased catalase (CAT) activity and decreased malondialdehyde (MDA) levels in LD muscle (p < 0.05). Meanwhile, greater levels of CAT and NRF2 mRNA and protein contents with VA treatment were observed in LD muscle (p < 0.05), partly explained by the increased level of RA (p < 0.05). Collectively, our findings indicated that VA injection at birth could improve lamb meat quality by elevating the redness, crude protein, crude fat, and antioxidative capacity in LD muscle of lambs
Manipulating Multiple Order Parameters via Oxygen Vacancies: The case of Eu0.5Ba0.5TiO3-{\delta}
Controlling functionalities, such as magnetism or ferroelectricity, by means
of oxygen vacancies (VO) is a key issue for the future development of
transition metal oxides. Progress in this field is currently addressed through
VO variations and their impact on mainly one order parameter. Here we reveal a
new mechanism for tuning both magnetism and ferroelectricity simultaneously by
using VO. Combined experimental and density-functional theory studies of
Eu0.5Ba0.5TiO3-{\delta}, we demonstrate that oxygen vacancies create Ti3+ 3d1
defect states, mediating the ferromagnetic coupling between the localized Eu
4f7 spins, and increase an off-center displacement of Ti ions, enhancing the
ferroelectric Curie temperature. The dual function of Ti sites also promises a
magnetoelectric coupling in the Eu0.5Ba0.5TiO3-{\delta}.Comment: Accepted by Physical Review B, 201
- …