2,899 research outputs found
Non-line-of-sight Node Localization based on Semi-Definite Programming in Wireless Sensor Networks
An unknown-position sensor can be localized if there are three or more
anchors making time-of-arrival (TOA) measurements of a signal from it. However,
the location errors can be very large due to the fact that some of the
measurements are from non-line-of-sight (NLOS) paths. In this paper, we propose
a semi-definite programming (SDP) based node localization algorithm in NLOS
environment for ultra-wideband (UWB) wireless sensor networks. The positions of
sensors can be estimated using the distance estimates from location-aware
anchors as well as other sensors. However, in the absence of LOS paths, e.g.,
in indoor networks, the NLOS range estimates can be significantly biased. As a
result, the NLOS error can remarkably decrease the location accuracy.
And it is not easy to efficiently distinguish LOS from NLOS measurements. In
this paper, an algorithm is proposed that achieves high location accuracy
without the need of identifying NLOS and LOS measurement.Comment: submitted to IEEE ICC'1
Split Fracture: A Complication of Cerclage Wiring of Acute Patellar Fracture
Introduction: Iatrogenic patellar fracture is reported as a complication of patella procedures, such as medial patellofemoral ligament reconstruction, reconstruction of the anterior cruciate ligament of the knee using bone-patellar tendon-bone technique, and resurfacing the patella in total knee arthroplasty.
Case Presentation: A 65-year-old lady with right patella fracture was treated with open reduction and cerclage wiring. An iatrogenic split fracture was noted during tension of the cerclage wire and was successfully managed by screw fixation of the split fracture.
Conclusions: Split fracture is a rare complication of circumferential cerclage wiring of patellar fracture. The surgeon should be aware of the contributing factors in order to avoid this complication
Effect of next-nearest neighbor coupling on the optical spectra in bilayer graphene
We investigate the dependence of the optical conductivity of bilayer graphene
(BLG) on the intra- and inter-layer interactions using the most complete model
to date. We show that the next nearest-neighbor intralayer coupling introduces
new features in the low-energy spectrum that are highly sensitive to sample
doping, changing significantly the ``universal'' conductance. Further, its
interplay with interlayer couplings leads to an anisotropy in conductance in
the ultraviolet range. We propose that experimental measurement of the optical
conductivity of intrinsic and doped BLG will provide a good benchmark for the
relative importance of intra- and inter-layer couplings at different doping
levels.Comment: 5 pages, 5 figure
A Neuroanatomical Signature for Schizophrenia Across Different Ethnic Groups
Schizophrenia is a disabling clinical syndrome found across the world. While the incidence and clinical expression of this illness are strongly influenced by ethnic factors, it is unclear whether patients from different ethnicities show distinct brain deficits. In this multicentre study, we used structural Magnetic Resonance Imaging to investigate neuroanatomy in 126 patients with first episode schizophrenia who came from 4 ethnically distinct cohorts (White Caucasians, African-Caribbeans, Japanese, and Chinese). Each patient was individually matched with a healthy control of the same ethnicity, gender, and age (±1 year). We report a reduction in the gray matter volume of the right anterior insula in patients relative to controls (P < .05 corrected); this reduction was detected in all 4 ethnic groups despite differences in psychopathology, exposure to antipsychotic medication and image acquisition sequence. This finding provides evidence for a neuroanatomical signature of schizophrenia expressed above and beyond ethnic variations in incidence and clinical expression. In light of the existing literature, implicating the right anterior insula in bipolar disorder, depression, addiction, obsessive-compulsive disorder, and anxiety, we speculate that the neuroanatomical deficit reported here may represent a transdiagnostic feature of Axis I disorders
The Role of Artificial Intelligence for Business Value
An increasing number of organizations are investing in Artificial intelligence (AI), but not all AI implementation leads to improved performance. To contribute to organizational business value, two components of AI resources, AI assets and AI capabilities, should be complementary in the business value creation process. In this study, based on IT business value literature and through the lens of dynamic capabilities, the role of AI resources in organizational value creation is explored. It is proposed that AI resources would enable organizations to develop process-oriented dynamic capabilities (PDCs), contributing to business value. This study will examine how organizations build AI capabilities and the roles of AI resources in creating business values through case studies. This research will offer a framework that guides and assists practitioners in utilising AI resources and building AI capabilities. A deeper understanding of the subject through this study also enriches the growing body of literature on AI
Properties and Device Applications of Hydrogenated Amorphous Silicon Carbide Films
Hydrogenated amorphous silicon carbide (a‐SiC:H) films were deposited with a radio‐frequency plasma‐enhanced chemical vapor deposition system which utilizes a dc electric field applied independently of the inductively coupled rf field. The source gases were SiH4 and CH4. It was found that application of an electric field directed out of the substrate surface enhances the growth rate and yields some improvements in photoconductivity. The compositions of the films were evaluated by x‐ray photoelectron spectroscopy for a range of source gas mixtures. In order to assess the applicability of a‐SiC:H thin films, heterojunction a‐SiC:H/crystalline Si (c‐Si) diodes were fabricated and their electrical characteristics evaluated. The diode capacitance‐voltage results confirmed a step junction, which was consistent with the abruptness of the interface demonstrated by high‐resolution transmission electron microscopy. The heterojunction diodes also showed good rectifying properties, suggesting promise for a‐SiC: H in device applications
360-Degree Complex Primary Reconstruction Using Porous Tantalum Cages for Adult Degenerative Spinal Deformity
Study Design: Retrospective cohort study. Objective: To assess both implant performance and the amount of correction that can be achieved using multilevel anterior lumbar interbody fusion (ALIF). Methods: Retrospective cohort study (n = 178) performed over a 4-year period. Surgical variables examined included blood loss, operative time, perioperative complications, and secondary/revision procedures. Follow-up radiographic assessment was performed to record implant-related problems. Radiographic parameters were examined pre- and postoperatively. Health-related quality of life (HRQOL) outcome measures were collected preoperatively and at 6 weeks, 6 months, 1 year, and 2 years postoperatively. Descriptive and comparative statistical analysis, using paired-sample t test and repeated-measures analysis of variance (rANOVA), was performed. Results: Lumbar lordosis increased from 42° ± 17° preoperatively to 55° ± 11° postoperatively (P < .001). The visual analog scale back pain mean score improved from 8.3 ± 1.5 preoperatively to 2.6 ± 2.4 at 2 years (P < .001). The mean Oswestry Disability Index improved from 69.5 ± 21.5 preoperatively to 19.9 ± 15.2 at 2 years (P < .001). The EQ-5D mean score improved from 0.2 ± 0.2 preoperatively to 0.8 ± 0.1 at 2 years (P = .02). There were no neurological, vascular, or visceral approach-related injuries reported. No rod breakages and no symptomatic nonunions occurred. There was one revision procedure performed for fracture. Conclusions: The use of porous tantalum cages as part of a 360-degree fusion to treat adult degenerative spinal deformity has been demonstrated to be a safe and effective strategy, leading to good clinical, functional, and radiographic outcomes in the short term
The Online Knapsack Problem with Departures
The online knapsack problem is a classic online resource allocation problem
in networking and operations research. Its basic version studies how to pack
online arriving items of different sizes and values into a capacity-limited
knapsack. In this paper, we study a general version that includes item
departures, while also considering multiple knapsacks and multi-dimensional
item sizes. We design a threshold-based online algorithm and prove that the
algorithm can achieve order-optimal competitive ratios. Beyond worst-case
performance guarantees, we also aim to achieve near-optimal average performance
under typical instances. Towards this goal, we propose a data-driven online
algorithm that learns within a policy-class that guarantees a worst-case
performance bound. In trace-driven experiments, we show that our data-driven
algorithm outperforms other benchmark algorithms in an application of online
knapsack to job scheduling for cloud computing
Photo-disintegration cross section measurements on W, Re and Os: Implications for the Re-Os cosmochronology
Cross sections of the W, Re, Os() reactions
were measured using quasi-monochromatic photon beams from laser Compton
scattering (LCS) with average energies from 7.3 to 10.9 MeV. The results are
compared with the predictions of Hauser-Feshbach statistical calculations using
four different sets of input parameters. In addition, the inverse neutron
capture cross sections were evaluated by constraining the model parameters,
especially the strength function, on the basis of the experimental data.
The present experiment helps to further constrain the correction factor
for the neutron capture on the 9.75 keV state in Os.
Implications of to the Re-Os cosmochronology are discussed with a
focus on the uncertainty in the estimate of the age of the Galaxy.Comment: 11 page
Pair production of the T-odd leptons at the LHC
The T-odd leptons predicted by the littlest model with T-parity can
be pair produced via the subprocesses ,
, and (= or
) at the Large Hadron Collider . We estimate the hadronic
production cross sections for all of these processes and give a simply
phenomenology analysis. We find that the cross sections for most of the above
processes are very small. However, the value of the cross section for the
process can reach .Comment: 12 pages, 2 figure
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