Carrier Frequency Offset Estimation Algorithm in the Presence of I/Q Imbalance in OFDM Systems

In this paper, we analyzed the feasibility of using a virtual carrier based carrier frequency offset estimation algorithm in the presence of I/Q imbalance in OFDM systems. Based on the analysis of the signal model with both receiver CFO and I/Q imbalance impairment we conclude that it is feasible to extending the virtual carrier based CFO estimation algorithm to the I/Q imbalance scenario. The CFO estimation performance is evaluated through computer simulation. Impact of parameters on the estimation performance is investigated and it is consistent with our analysis. After CFO correction, a blind based I/Q imbalance estimation and compensation algorithm is applied. The final detection performance demonstrates that the virtual carrier based CFO estimation performance is good enough for subsequent I/Q imbalance estimation and compensation

Text Categorization and Machine Learning Methods: Current State Of The Art

In this informative age, we find many documents are available in digital forms which need classification of the text. For solving this major problem present researchers focused on machine learning techniques: a general inductive process automatically builds a classifier by learning, from a set of pre classified documents, the characteristics of the categories. The main benefit of the present approach is consisting in the manual definition of a classifier by domain experts where effectiveness, less use of expert work and straightforward portability to different domains are possible. The paper examines the main approaches to text categorization comparing the machine learning paradigm and present state of the art. Various issues pertaining to three different text similarity problems, namely, semantic, conceptual and contextual are also discussed

Hydrodynamic Performance and Acoustic Response of Ship Propeller

The aim of the paper is to predict the hydrodynamic performance and noise generated by the propeller at different advance ratio and the speed of the propeller. Three bladed, DTMB 4119 propeller model was created using the NACA66 modified line, a = 0.8 hydrofoil profile. ANSYS Workbench software is used for mesh generation and computational analysis. A large-eddy simulation turbulence model and Ffowcs Williams-Hawkings (FWH) acoustic model is used for all simulations. A moving reference frame is used to simulate the rotational effects of the propeller. The speed of the propeller is 792 rpm, the propeller being 0.2 m, and inlet velocity is varied to study the effect of the advance ratio. A transient analysis is carried out using a time step value of 0.0005 seconds and the total simulation time is 0.6 seconds. The hydrodynamic performance parameters are validated by comparing with the experimental data available in the literature. The sound pressure level (SPL) is plotted over the frequency range of 0 to 1000 Hz at different locations, speed, and an advance ratio of 0.5, 0.7, 0.833, and 0.9,1. The structural, acoustic and hydrodynamic behaviour of the propeller was predicted using a two-way fluid structure interaction at an advance ratio of 0.833. The major conclusions drawn from the analysis are that the sound pressure level values are increased at the propeller off-design conditions and varying with the receiver locations. The data generated from this study is useful for the designers to carry out further research in order to reduce the noise generated from the propeller

Enhancement of magnetic and electrical properties in Sc substituted BiFeO3 multiferroic

Polycrystalline BiFe1-xScxO3 (x=0, 0.05, 0.1 and 0.15) compounds are prepared using solid state reaction. The XRD patterns show that all compounds are crystallized in rhombohedral structure with R3c space group. An induced weak ferromagnetism in Sc substituted BiFeO 3 due to suppression of spiral modulated spin structure is revealed. In addition, a spin glass like behaviour is observed from the zero field cooled (ZFC) and field cooled (FC) magnetization curves in the low temperature region. Further, the coupling between the ferroelectric and (anti) ferromagnetic orders is evident from the appearance of anomaly in the dielectric data near the magnetic Néel temperature (373 °C). The reduction of oxygen vacancies due to Sc substitution is evident from the ac conductivity data and the suppressed anomaly in dielectric data at 220 °C. The temperature dependence of ac conductivity is consistent with correlated barrier hopping (CBH) model. The temperature dependent ac conductivity and activation energies indicate that electronic conduction, oxygen vacancies movement and creation of defects are the prime contributors to the ac conductivity in measured temperature regions. The improved magnetic and electrical properties due to the structural modification are prominent for novel device applications

Analysis of spontaneously reported cutaneous adverse drug reactions in a tertiary care teaching hospital in South India

Background: Skin is the most common organ involved in adverse reactions due to drugs. With newer drugs released into market every year, there is changing pattern of the reported cutaneous adverse drug reactions (ADRs). In order to ensure safer use of medicines in patients, there is need for continuous monitoring of ADRs. This is a retrospective study to analyse spontaneously reported cutaneous ADRs.Methods: All the cutaneous ADRs reported between January 2017 and September 2018 were analysed for clinical patterns, suspected medications, causality, severity and preventability.Results: Of the 1035 reports received during the study period, 232 (22.41%) included cutaneous reactions. 113 (48.7%) were male and 119 (51.29%) were female. Maculopapular rash 70 (30.17%), pruritus 31 (13.36%), palmar plantar erythrodysesthesia 30 (12.93%), acne 19 (8.19%), urticaria 16 (6.89%) and fixed drug eruptions (FDE) 13 (5.6%) were the common clinical patterns. Antimicrobial agents followed by anticancer drugs, nonsteroidal anti-inflammatory drugs (NSAIDs), hormones and related drugs, and antiepileptic drugs were the common suspected group of drugs. Causality assessment as done by WHO-UMC scale showed that 3 (1.29%) were certainly related, 174 (75%) were probably related and 55 (23.7%) were possibly related to the suspected medication.Conclusions: Cutaneous ADRs are most frequently reported ADRs in the present study. With newer drugs released into market, there is a need for continuous monitoring of use of drugs to promote safer use of medicines in patients

Thermal Analysis of Exhaust Manifold Coating with High Temperature Resistant Materials

:  In IC engines exhaust system plays an important role in delivering the waste gases to a safe distance and also it helps in reducing the sound pollution and air pollution ,these exhaust systems ,mainly exhaust manifolds suffer a lot of thermal stress the life of the manifold is much effected due to the exposer with hot flue gases ,sometimes due to emissive heating these manifolds will get blow holes and produce a lot of noise , zirconia based materials exhibits low thermal conductivity, high hardness, and stable fracture toughness compared to other evaluated materials. One material that can be applicable in diesel exhaust application is mullite, which showed similar performance to zirconia based materials. In this study we design a exhaust manifold with different coatings on it and we test it with Finite Element Methodology, but due to design limitations and some messing problem the work is carried forward by assuming complete body with coating material  both temperature distribution and thermal stress concentrations are calculated using Finite Element Methodology. For modelling Catia V5 R20 is used and for Finite Element Methodology Ansys 15.0 is used

Rare occurrence of sunfish Mola mola (Linnaeus) from the coastal waters off Visakhapatnam (Bay of Bengal)

The occurrence of sunfish in any sea is a rare event. It is so rare that even fishermen engaged in fishing throughout their lives find it totally strange when they come across one. On 6 May, 1986, a local fisherman reported to the Zoology Department of the Andhra University that a very strange looking fish was part of that day's catch