Optimal Detector Randomization in Cognitive Radio Systems in the Presence of Imperfect Sensing Decisions

Cataloged from PDF version of article.In this study, optimal detector randomization is developed for secondary users in a cognitive radio system in the presence of imperfect spectrum sensing decisions. It is shown that the minimum average probability of error can be achieved by employing no more than four maximum a-posteriori probability (MAP) detectors at the secondary receiver. Optimal MAP detectors and generic expressions for their average probability of error are derived in the presence of possible sensing errors. Also, sufficient conditions are presented related to improvements due to optimal detector randomization. © 2014 IEEE

Optimum Power Allocation for Average Power Constrained Jammers in the Presense of Non-Gaussian Noise

Cataloged from PDF version of article.We study the problem of determining the optimum power allocation policy for an average power constrained jammer operating over an arbitrary additive noise channel, where the aim is to minimize the detection probability of an instantaneously and fully adaptive receiver employing the Neyman-Pearson (NP) criterion. We show that the optimum jamming performance can be achieved via power randomization between at most two different power levels. We also provide sufficient conditions for the improvability and nonimprovability of the jamming performance via power randomization in comparison to a fixed power jamming scheme. Numerical examples are presented to illustrate theoretical results

Density functional theory studies of MTSL nitroxide side chain conformations attached to an activation loop

A quantum-mechanical (QM) method rooted on density functional theory (DFT) linked to the Stochastic Liouville equation (SLE) in the Fokker Planck (FP) form has been employed for the first time to sample the methane-thiosulfonate spin label (MTSL) conformational space attached to the Aurora-A kinase activation loop and to calculate the EPR spectrum. The features of the calculated energy surface allowed us to describe the system in a limited number of rotamers stabilized by interactions of the MTSL side chain and neighbouring residues. The relevant magnetic parameters and the electron paramagnetic resonance (EPR) spectrum were subsequently calculated from the trajectories of the spin probe in the protein environment. The comparison between theoretical and experimental continuous wave (CW) EPR spectra revealed some small differences in the EPR line shape which arises from the combinations of g- and A-values obtained from the conformations selected. The theoretical approach adopted in this work can be used to recognise the contribution of MTSL rotamers to the EPR spectrum in order to help extract structural/dynamics properties of protein from the experimental data

Reduced functional measure of cardiovascular reserve predicts admission to critical care unit following kidney transplantation

Background: There is currently no effective preoperative assessment for patients undergoing kidney transplantation that is able to identify those at high perioperative risk requiring admission to critical care unit (CCU). We sought to determine if functional measures of cardiovascular reserve, in particular the anaerobic threshold (VO2AT) could identify these patients. Methods: Adult patients were assessed within 4 weeks prior to kidney transplantation in a University hospital with a 37-bed CCU, between April 2010 and June 2012. Cardiopulmonary exercise testing (CPET), echocardiography and arterial applanation tonometry were performed. Results: There were 70 participants (age 41.7614.5 years, 60% male, 91.4% living donor kidney recipients, 23.4% were desensitized). 14 patients (20%) required escalation of care from the ward to CCU following transplantation. Reduced anaerobic threshold (VO2AT) was the most significant predictor, independently (OR = 0.43; 95% CI 0.27–0.68; p,0.001) and in the multivariate logistic regression analysis (adjusted OR = 0.26; 95% CI 0.12–0.59; p = 0.001). The area under the receiveroperating- characteristic curve was 0.93, based on a risk prediction model that incorporated VO2AT, body mass index and desensitization status. Neither echocardiographic nor measures of aortic compliance were significantly associated with CCU admission. Conclusions: To our knowledge, this is the first prospective observational study to demonstrate the usefulness of CPET as a preoperative risk stratification tool for patients undergoing kidney transplantation. The study suggests that VO2AT has the potential to predict perioperative morbidity in kidney transplant recipients

The Relation Between the Surface Brightness and the Diameter for Galactic Supernova Remnants

In this work, we have constructed a relation between the surface brightness ($\Sigma$) and diameter (D) of Galactic C- and S-type supernova remnants (SNRs). In order to calibrate the $\Sigma$-D dependence, we have carefully examined some intrinsic (e.g. explosion energy) and extrinsic (e.g. density of the ambient medium) properties of the remnants and, taking into account also the distance values given in the literature, we have adopted distances for some of the SNRs which have relatively more reliable distance values. These calibrator SNRs are all C- and S-type SNRs, i.e. F-type SNRs (and S-type SNR Cas A which has an exceptionally high surface brightness) are excluded. The Sigma-D relation has 2 slopes with a turning point at D=36.5 pc: $\Sigma$(at 1 GHz)=8.4$^{+19.5}_{-6.3}$$\times10^{-12}$ D$^{{-5.99}^{+0.38}_{-0.33}}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ (for $\Sigma$$\le3.7\times10^{-21}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ and D$\ge$36.5 pc) and $\Sigma$(at 1 GHz)=2.7$^{+2.1}_{-1.4}$$\times$ 10$^{-17}$ D$^{{-2.47}^{+0.20}_{-0.16}}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ (for $\Sigma$$>3.7\times10^{-21}$ Wm$^{-2}$Hz$^{-1}$ster$^{-1}$ and D$<$36.5 pc). We discussed the theoretical basis for the $\Sigma$-D dependence and particularly the reasons for the change in slope of the relation were stated. Added to this, we have shown the dependence between the radio luminosity and the diameter which seems to have a slope close to zero up to about D=36.5 pc. We have also adopted distance and diameter values for all of the observed Galactic SNRs by examining all the available distance values presented in the literature together with the distances found from our $\Sigma$-D relation.Comment: 45 pages, 2 figures, accepted for publication in Astronomical and Astrophysical Transaction

Regional prediction of landslide hazard using probability analysis of intense rainfall in the Hoa Binh province, Vietnam.

The main objective of this study is to assess regional landslide hazards in the Hoa Binh province of Vietnam. A landslide inventory map was constructed from various sources with data mainly for a period of 21 years from 1990 to 2010. The historic inventory of these failures shows that rainfall is the main triggering factor in this region. The probability of the occurrence of episodes of rainfall and the rainfall threshold were deduced from records of rainfall for the aforementioned period. The rainfall threshold model was generated based on daily and cumulative values of antecedent rainfall of the landslide events. The result shows that 15-day antecedent rainfall gives the best fit for the existing landslides in the inventory. The rainfall threshold model was validated using the rainfall and landslide events that occurred in 2010 that were not considered in building the threshold model. The result was used for estimating temporal probability of a landslide to occur using a Poisson probability model. Prior to this work, five landslide susceptibility maps were constructed for the study area using support vector machines, logistic regression, evidential belief functions, Bayesian-regularized neural networks, and neuro-fuzzy models. These susceptibility maps provide information on the spatial prediction probability of landslide occurrence in the area. Finally, landslide hazard maps were generated by integrating the spatial and the temporal probability of landslide. A total of 15 specific landslide hazard maps were generated considering three time periods of 1, 3, and 5 years

The solid effect of dynamic nuclear polarization in liquids – accounting for <i>g</i>-tensor anisotropy at high magnetic fields

In spite of its name, the solid effect of dynamic nuclear polarization (DNP) is also operative in viscous liquids, where the dipolar interaction between the polarized nuclear spins and the polarizing electrons is not completely averaged out by molecular diffusion on the timescale of the electronic spin–spin relaxation time. Under such slow-motional conditions, it is likely that the tumbling of the polarizing agent is similarly too slow to efficiently average the anisotropies of its magnetic tensors on the timescale of the electronic T2. Here we extend our previous analysis of the solid effect in liquids to account for the effect of g-tensor anisotropy at high magnetic fields. Building directly on the mathematical treatment of slow tumbling in electron spin resonance (Freed et al., 1971), we calculate solid-effect DNP enhancements in the presence of both translational diffusion of the liquid molecules and rotational diffusion of the polarizing agent. To illustrate the formalism, we analyze high-field (9.4 T) DNP enhancement profiles from nitroxide-labeled lipids in fluid lipid bilayers. By properly accounting for power broadening and motional broadening, we successfully decompose the measured DNP enhancements into their separate contributions from the solid and Overhauser effects.</p

Carbon and proton Overhauser DNP from MD simulations and ab initio calculations: TEMPOL in acetone

This journal is © the Owner Societies 2015. A computational analysis of the Overhauser effect is reported for the proton, methyl carbon, and carbonyl carbon nuclei of liquid acetone doped with the nitroxide radical TEMPOL. A practical methodology for calculating the dynamic nuclear polarization (DNP) coupling factors by accounting for both dipole-dipole and Fermi-contact interactions is presented. The contribution to the dipolar spectral density function of nuclear spins that are not too far from TEMPOL is computed through classical molecular dynamics (MD) simulations, whereas the contribution of distant spins is included analytically. Fermi contacts are obtained by subjecting a few molecules from every MD snapshot to ab initio quantum mechanical calculations. Scalar interaction is found to be an essential part of the 13C Overhauser DNP. While mostly detrimental to the carbonyl carbon of acetone it is predicted to result in large enhancements of the methyl carbon signal at magnetic fields of 9 T and beyond. In contrast, scalar coupling is shown to be negligible for the protons of acetone. The additional influence of proton polarization on the carbon DNP (three-spin effect) is also analyzed computationally. Its effect, however, is concluded to be practically insignificant for liquid acetone

TEKSTİL ÇALIŞANLARINDA, KATILIM İLE MESLEKİ KAS İSKELET SİSTEMİ RAHATSIZLIĞI VE MESLEKİ TÜKENMİŞLİK ARASINDAKİ İLİŞKİ

Bu çalışma tekstil ve hazır giyim sektöründe çalışan kişilerde katılım ile mesleki kas iskelet sistemi rahatsızlıkları ve mesleki tükenmişlik seviyesi arasındaki ilişkiyi incelemek amacıyla yapılmıştır. Çalışmamıza 31 kadın, 69 erkek olmak üzere toplam 100 tekstil/konfeksiyon çalışanı dahil edilmiştir. Katılımcılara Sosyodemografik Bilgi Formu, Genişletilmiş NORDIC Kas-İskelet Sistemi Anketi, Maslach Tükenmişlik Envanter Genel Anketi ve Katılım Ölçeği uygulandı. Katılımcıların yaş ortalaması 34,36’dır (min:18-max:61). Katılımcıların %40’ının 10 yıl ve üzeri bir süreyle tekstil/konfeksiyon işinde çalıştıkları kaydedilmiştir. Katılımcıların %5’inin 6-8 saat arasında ve %29’unun 8-10 saat arasında çalıştığı saptanmıştır. Katılımcılarda en fazla bel, boyun, sırt, omuz ve diz ağrısı şikayetlerine rastlanılmıştır. Bununla birlikte katılımcıların %43’ünün orta düzey mesleki tükenmişliğe ve %88’inin katılım kısıtlılığına sahip olduğu bulunmuştur. İstatistiksel analiz sonucunda katılımcıların, katılım kısıtlılıkları ile mesleki tükenmişlikleri arasında istatistiksel olarak pozitif yönde, yüksek düzeyde anlamlı bir ilişki olduğu tespit edilmiştir (p=0,000). Ancak, katılım ile mesleki kas-iskelet rahatsızlıkları arasında istatistiksel olarak anlamlı bir ilişki bulunmamıştır (p=0,069). Bu veriler doğrultusunda tekstil ve hazır giyim sektöründe daha önce ele alınan konulara ek olarak katılım alanının ergoterapistlerce değerlendirilerek müdahale edilmesi gereken bir alan olduğunu düşünmekteyiz.This study was conducted to examine the relationship between participation in the textile and garment sector, occupational musculoskeletal disorders and the level of occupational burnout. 31 women, 69 male, totaling 100 textile/apparel employees were included in the study. Sociodemographic Information Form, Extended NORDIC Musculoskeletal System Questionnaire, Maslach Burnout Inventory and Participation Scale were applied to the participants. The mean age of the participants was 34.36 (min:18-max: 61). It was noted that 40% of the participants for 10 years and over worked in the textile/apparel business. It was observed that 5% of the participants worked between 6-8 hours and 29% between 8-10 hours. The most common complaints were low back, neck, back, shoulder and knee pain in the participants. In addition, it was found that 43% of the participants had moderate occupational burnout and 88% had participation limitation. As a result of the statistical analysis, it was determined that there was a statistically positive, highly significant relationship between the participants' participation limitations and their occupational burnout (p=0,000). However, it was found that there was no statistically significant relationship between participation and occupational musculoskeletal disorders. (p=0.069). In line with these data, we think that in addition to the subjects previously discussed in the textile and garment sector, the participation area is an area that should be evaluated and intervened by occupational therapists