Jamming Detection using Wavelet Transforms

Modern Global Navigation Satellite Systems (GNSS), such as GPS and Galileo, play vital role in providing high precision navigation and positioning services for civilian and military applications. The high precision feature of these systems is compromised in the presence of interference, particularly intentional narrowband interference otherwise commonly known as jamming. To ensure the sustainability of high precision, removal of jamming components is necessary. In order to achieve successful elimination of jamming components, efficient detection and understanding of the nature of jamming signals are vital. In practice, signals are finite in nature and vary over time. Mathematical tools such as Fourier transforms assume signals are infinite (periodic), thereby fail to capture accurate time-related information. To overcome this situation, a sophisticated technique that captures valuable information in both time and frequency domains is required. One such technique is the wavelet transform. Wavelet transform involves successive scaling of fast decaying wavelike oscillations known as wavelets in time and shifting it along the duration of an incoming signal. This process results in either stretching or shrinking of wavelets. Stretched wavelet facilitates the extraction of slow variations in a signal and compressed wavelet facilitates the extraction of abrupt variations. The conceived algorithm detects the presence of jamming signals, simultaneously capturing features such as frequency, bandwidth and duration. The operational capability of the algorithm was tested for GNSS signals operating in L1 frequency band (1575.42MHz) such as GPS L1 and Galileo E1. The parameters defined to measure the efficiency of the algorithm are detection probability (Pd) and false alarm probability (Pfa). Pd is estimated for different values of jammer to signal ratio (JSR) with fixed signal to noise ratio (SNR) and Pfa depends on the choice of detection threshold (T). T is chosen such that Pfa is as low as possible. The detector works better in low noise and high jammer power scenarios. Keywords: Jamming, Wavelets, GPS, Galileo, SNR, JSR, L

Determination of Material Parameters during Superplastic Forming of AA 5086 Alloy

AbstractSuperplastic forming (SPF) process is an important advanced manufacturing method that has the benefit of certain materials capability to undergo large strains to failure when deformed atprominent temperature and at lesser strain rates. The major problem encountered during the Superplastic Forming of sheet metals, is the vagueness in determining the specific time necessary for attaining the steady state temperature, forming time by the sheet material to arrive the required geometry for a given input parameters such as pressure and temperature, thickness distribution along the profile. Hence in this work, a steady state equation is derived to determine the approximate time for the sheet metal to attain the set temperature and also the most favorable temperature and pressure necessary for achieving the deformation of the workpiece based on equal thickness distribution is determined. Graphs are plotted to show the varying parameters at different temperature and pressure values

Assessment on the harnessing of the energy from the back pressure chamber of palm oil mill

Malaysia being the second largest palm oil producer produced bio mass as a by-product. Essentially the bio mass is used as energy resource in the palm industry to cater for power requirements through co-generation process. However part of the unused steam is let out to the atmosphere through the back pressure chamber. Most of the mills are in the position to generate more power and supply electricity to nearby residential areas. In some or in most of the cases the low pressure steam is let to atmosphere as the power produced is normally more than sufficient for use in the palm oil mill. The assessment on the feasibility of recovering the let out steam through a small turbine generator set is presented in this paper. Also the choice on the optimal valve size used in the expansion of the turbine is found to influence the power production. The estimation on the available energy through this is about 35% of the main plant used energy for the optimal valve sizing of 3 inch. A numerical design analysis on the back pressure chamber energy is developed and the computations on the energy are presented

Maternal near miss review from a tertiary care center in South India

Background: Maternal near miss review acts as complimentary for mortality audits. It indicates the quality of obstetric care and helps obstetricians to revise policies and practices.Methods: A retrospective observational study was carried out at institute of maternal and child health, Government Medical College Kozhikode from January to December 2014. Cases were defined based on WHO criteria 2009.Results: Total live births during the study period were 15604 and there were 24 maternal deaths. Near Miss cases were 267. Maternal mortality rate was 153.5/lakh live births and maternal near miss incidence ratio was 17.03/1000 live births. Maternal near miss to mortality ratio was 11.1 and mortality index was 8.2%. Hypertensive disorders comprised 46%, followed by haemorrhage 36%, sepsis 7% and other causes 10%.Conclusions: Even with improving care, maternal near miss incidence (17.03 per 1000 live births) is found to be higher in our institution compared to developed nations. However high maternal near miss to mortality ratio (11.1) and low mortality index (8.2%) shows good quality of obstetric care in our institution

Long single crystalline α-Mn2O3 nanorods: facile synthesis and photocatalytic application

Single crystalline cubic sesquioxide bixbyite α-Mn2O3 nanorods have been synthesized successfully by a simple, low cost, environmental benign hydrothermal route. As synthesized γ-MnOOH were calcined at 600 °C to obtain α-Mn2O3 nanorods, which were further subjected to various characterizations. The alpha manganese sesquioxide cubic bixbyite-type oxide formation was confirmed by the XRD studies. The surface morphology and elemental analysis were explored by SEM with EDX studies, respectively. High-resolution transmission electron microscopy HRTEM and SAED showed that the α-Mn2O3 nanorods were single crystalline and were grown along the C-axis of the crystal plane. The UV–visible spectrum indicated that the absorption was prominent in the ultraviolet region. In addition, PL spectrum result of α-Mn2O3 nanorods recommended possible photocatalytic applications. The photocatalyst ensures a new platform for the decolorization of dye molecules of the harmful cationic dyes like methylene blue and rhodamine B. Possible growth mechanism and photocatalytic dye degradation mechanism were proposed for synthesized α-Mn2O3 nanorods

A study on the utility of preventive health check-up in early detection of disease states

Background: Because of the current lifestyle and food habits, people are becoming more vulnerable to many diseases like diabetes, hypertension, dyslipidemia and coronary artery disease. Early detection of disease in its latent phase helps in timely therapeutic interventions, thereby significantly reducing the morbidity and mortality. Preventive health check-up is widely adopted by many hospitals towards this goal. The aim of the study was to analyze the utility of master health check-up in early detection of disease states.Methods: Retrospective study of 262 asymptomatic individuals attending Master Health Checkup section was done. Patients with significant symptoms were excluded. Descriptive analysis was used in the processing and analysis of data.Results: In the study population, 12.8% had diabetic range of blood sugar values and 21.7% had BP in the hypertensive range. Dyslipidemia was detected in 89.2% of asymptomatic individuals. Thyroid function abnormalities were detected in 10.7% of the population. Among other newly detected diseases, detection rates were 40.9% for NAFLD, 4.2% for renal impairment and 26.7% for anemia.Conclusions: The study results are encouraging to educate the society to utilize preventive health services, as significant number of disease states were newly detected in the preventive health check-up

Epigenetic and neurological effects and safety of high-dose nicotinamide in patients with Friedreich's ataxia: an exploratory, open-label, dose-escalation study

Background: Friedreich's ataxia is a progressive degenerative disorder caused by deficiency of the frataxin protein. Expanded GAA repeats within intron 1 of the frataxin (FXN) gene lead to its heterochromatinisation and transcriptional silencing. Preclinical studies have shown that the histone deacetylase inhibitor nicotinamide (vitamin B3) can remodel the pathological heterochromatin and upregulate expression of FXN. We aimed to assess the epigenetic and neurological effects and safety of high-dose nicotinamide in patients with Friedreich's ataxia. Methods: In this exploratory, open-label, dose-escalation study in the UK, male and female patients (aged 18 years or older) with Friedreich's ataxia were given single doses (phase 1) and repeated daily doses of 2–8 g oral nicotinamide for 5 days (phase 2) and 8 weeks (phase 3). Doses were gradually escalated during phases 1 and 2, with individual maximum tolerated doses used in phase 3. The primary outcome was the upregulation of frataxin expression. We also assessed the safety and tolerability of nicotinamide, used chromatin immunoprecipitation to investigate changes in chromatin structure at the FXN gene locus, and assessed the effect of nicotinamide treatment on clinical scales for ataxia. This study is registered with ClinicalTrials.gov, number NCT01589809. Findings: Nicotinamide was generally well tolerated; the main adverse event was nausea, which in most cases was mild, dose-related, and resolved spontaneously or after dose reduction, use of antinausea drugs, or both. Phase 1 showed a dose-response relation for proportional change in frataxin protein concentration from baseline to 8 h post-dose, which increased with increasing dose (p=0·0004). Bayesian analysis predicted that 3·8 g would result in a 1·5-times increase and 7·5 g in a doubling of frataxin protein concentration. Phases 2 and 3 showed that daily dosing at 3·5–6 g resulted in a sustained and significant (p<0·0001) upregulation of frataxin expression, which was accompanied by a reduction in heterochromatin modifications at the FXN locus. Clinical measures showed no significant changes. Interpretation: Nicotinamide was associated with a sustained improvement in frataxin concentrations towards those seen in asymptomatic carriers during 8 weeks of daily dosing. Further investigation of the long-term clinical benefits of nicotinamide and its ability to ameliorate frataxin deficiency in Friedreich's ataxia is warranted

Challenges and solutions to recruitment of neonates and children having cardiac surgery into a study using a novel sampling device

OBJECTIVE: To narratively describe the challenges and solutions required in delivering a non-commercial study of children undergoing cardiac surgery using a novel subcutaneous hormone collection device. RESULTS: The challenges faced by the research team are divided into those of conducting healthcare research in children and those specific to this study. Many of the issues of conducting healthcare research in children can and have been overcome by structural and institutional culture change–normalising and embedding research as part of good clinical care. The issues specific to insertion and maintenance of the novel collection device can be overcome by education and support of the clinical teams. The increased incentives and resources of commercial research may have overcome many of these