MIMO Systems: Principles, Iterative Techniques, and advanced Polarization

International audienceThis chapter considers the principles of multiple-input multiple-output (MIMO) wireless communication systems as well as some recent accomplishments concerning their implementation. By employing multiple antennas at both transmitter and receiver, very high data rates can be achieved under the condition of deployment in a rich-scattering propagation medium. This interesting property of MIMO systems suggests their use in the future high-rate and high-quality wireless communication systems. Several concepts in MIMO systems are reviewed in this chapter. We first consider MIMO channel models and recall the basic principles of MIMO structures and channel modeling. We next study the MIMO channel capacity and present the early developments in these systems concerning the information theory aspect. Iterative signal detection is considered next; it considers iterative techniques for space-time decoding. As the capacity is inversely proportional to the spatial channel correlation, MIMO antennas should be sufficiently separated, usually by several wavelengths. In order to minimize antennas' deployment, we present advanced polarization diversity techniques for MIMO systems and explain how they can help to reduce the spatial correlation in order to achieve high transmission rates. We end the chapter by considering the application of MIMO systems in local area networks, as well as their potential in enhancing range, localization, and power efficiency of sensor networks

Evaluation of the Strategy for Support via Swedish Civil Society Organisations 2010-2014: Final Country Report - Pakistan

This report shares the findings and recommendations from an evaluation of Sweden’s Civil Society Strategy 2010–2014 as implemented by Swedish civil society organisations and their national partners in Pakistan, as one of three country studies. The purpose of the evaluation was to find out if, how and why/why not Sweden’s support to civil society organisations has contributed to the overall objectives of the strategy. The Reality Check Approach was used to understand the realities and perspectives of people living in poverty combined with ‘mesolevel’ and organisational inquiries. The findings were used to explore the theories of change of the organisations in relation to people’s realities, in order to analyse the strategy’s relevance, alignment and feasibility

10 kW Grid-Connected PV System Cost and Environmental Analysis for Government Offices: Darbandikhan Technical Institute as a Case Study

The Iraqi Kurdistan region has significant potential for implementing solar energy with an average annual rate of 5.245 kWh/m2. However, most of its energy supply currently comes from nonrenewable energy sources. With the continually increasing demand for energy, an alternative energy-generation technique is required. Among the various renewable energy resources, generating electricity directly from sunlight is the best option because it can be applied by the average household and is environmentally friendly. In this study, a cost and environmental analysis for a 10 kW grid-connected photovoltaic system is presented for a government building with the aim of reducing the load demand on the grid during weekdays and also to inject the generated power into the power grid during weekends. A simulation of the proposed PV system was generated by using Photovoltaic Geographic Information System software to estimate the system’s production performance. The software showed that the highest energy production was 1,660 kWh, which occurred in August; the total electricity production was 16,184 kWh over a 1-year period. The study also showed that the geographical location of Darbandikhan City is quite sufficient for generating electric power from solar energy. It further showed that it can reduce CO2 emissions by 356.60 tons during its lifetime when compared with a gasoline generator and by 131.38 tons when compared with that of a natural gas generator. The proposed system could serve as a good revenue source for the government by exporting the generated electricity to the grid while at the same time serving as motivation for households in the region; furthermore, this system can also be applied to other governmental offices in Kurdistan to generate some or all of its energy needs

Optimum directional well path design considering collapse and fracture pressures

Well path optimisation is often done based on the wellbore stability where the production related concerns are ignored. In fact, many of the studies carried out in the past have not included hydraulic fractures into their calculations. In fact, an optimum path for wellbore should not only provide the maximum stability during drilling but also offer a relatively low pressure to fracture the formation in the production stage. In this study, attempts are made to provide a methodology to determine an optimum well path for drilling, hydraulic fracturing and production stage using wellbore stability analysis in different stress regimes. An analytical model was proposed and used to determine the collapse pressure and fracture gradient during drilling and hydraulic fracturing at various azimuths and inclinations. The results obtained revealed that the well path does not change in a normal faulting regime during production. However, the azimuth and inclination of wells may need to be changed in the strike-slip and reverse fault regimes for a better drilling and fracturing. It was also found that deviated wells can be a better option in normal and strike-slip stress regimes, but further studies might be needed to confirm these findings.acceptedVersio

Behavior of Recycled Aggregate Fibrous Reinforced Beams Under Flexural and Shear Loading

The use of recycled concrete aggregates (RCA) to replace part or all of the natural coarse aggregates (NCA) in the production of concrete has been on the increase. Such use helps in the protection of the natural resources and in the reduction in the use o f landfills. The experimental work consists of casting and testing ten rectangular simply supported reinforced concrete beams of dimensions (1500*150*240) mm with concentric point load at mid span as well as tests for control specimens to determine the mechanical prope rties of the concert. Five beams of these ten beams were designed to fail in flexure and other five beams were designed to fail in shear. Two beams were considering as a reference beams using normal aggregate (NCA) and two beams were considering as a refer ence beams using recycled aggregate (RCA. The other six beams were cast using recycled concrete aggregates (RCA) with steel fiber in three different volumetric ratio (vf).The present investigation contains three main variables: Coarse aggregate (normal and recycled). Transverse reinforcement (with stirrups spacing 50 mm for flexure failure mode and without stirrups for shear failure mode). Steel fiber (vf) = (0.5) %, (1) % and (1.5) %. In addition, constant longitudinal reinforcement ratio 0.012 . Experiment al results have generally showed that ultimate loads (Pu) of beams made with RA are approximately close to the results of beams made with NA but with decrease of values (14% and 21%) for flexural and shear behavior respectively. The ultimate load of fibrou s concrete beams is greater than beams without steel fiber by (33% - 50%) for shear behavior and (21% - 35%) for flexure behavior

The Role of Prophylactic Antibiotics in Prevention of Wound Infections in Open Appendectomy Patients in Al-Diwaniayh Teaching Hospital

Knowing how, when, and what types of antibiotics should be used before and after an appendectomy is a very important subject for this very common intra-abdominal procedure that is performed in an emergency setting. This subject reflects the positive results of the procedure on the reduction of infectious complications, such as surgical site infection or intra-abdominal abcess.  Post-operatively, we divided patients who had a non-perforated appendix into two groups: group A received pre-operative antibiotics half an hour before surgery with a single dose of 3rd generation cephalosporin (ceftriaxone)1g and metronidazole 500mg, and group B received antibiotics half an hour pre-operatively and continued antibiotics post-operatively within 24 hours. Both groups received antibiotics post-operatively. 240 patients were randomly selected and separated into two groups with an identical number in each. Of the 120 patients in group A, eight of them developed a wound infection (6.67%), and the same number of patients in group B also became infected. The 30-day follow-up period came and went without anyone developing an intra-abdominal infection. The use of a single dosage of antibiotic will be sufficient to prevent infection at the surgical site, and the advantage of post-operative antibiotic treatment in non-perforated appendix will be imperceptible

Automatic Speech Emotion Recognition Using Machine Learning

This chapter presents a comparative study of speech emotion recognition (SER) systems. Theoretical definition, categorization of affective state and the modalities of emotion expression are presented. To achieve this study, an SER system, based on different classifiers and different methods for features extraction, is developed. Mel-frequency cepstrum coefficients (MFCC) and modulation spectral (MS) features are extracted from the speech signals and used to train different classifiers. Feature selection (FS) was applied in order to seek for the most relevant feature subset. Several machine learning paradigms were used for the emotion classification task. A recurrent neural network (RNN) classifier is used first to classify seven emotions. Their performances are compared later to multivariate linear regression (MLR) and support vector machines (SVM) techniques, which are widely used in the field of emotion recognition for spoken audio signals. Berlin and Spanish databases are used as the experimental data set. This study shows that for Berlin database all classifiers achieve an accuracy of 83% when a speaker normalization (SN) and a feature selection are applied to the features. For Spanish database, the best accuracy (94 %) is achieved by RNN classifier without SN and with FS

Prevalence of Upper Extremity Musculoskeletal Disorders in Dentists: Symptoms and Risk Factors

Aim. The purpose of the present research was to examine the factors that lead to musculoskeletal disorders in dentists by assessing their posture using RULA method. Materials and Methods. In this cross-sectional study, 130 dentists (84 male and 46 female) participated. The posture of the subjects during their normal workload was recorded by using the RULA method, and the range of musculoskeletal pains by using the Nordic Musculoskeletal Questionnaire (NMQ), and individual and professional data was assessed by a demographics questionnaire. All tests were performed at the P<0.05 level. Results. Assessment of the physical status of the subjects showed that 82.8% of subjects were at high risk of musculoskeletal disorders. The majority of musculoskeletal pains were in the neck (55.9%) and the shoulder (43.8%). Moreover, 68.9% of the subjects had experienced pain at least once over the last year. Significant relationships were observed between musculoskeletal pain and daily work hours P=0.07 and number of patients P=0.02, but the pain was not significantly associated with BMI and experience. Conclusion. The present findings showed that unsuitable posture of dentists during work has a considerable effect on musculoskeletal disorders. Therefore, further investigation is required to avoid the detrimental effects of wrong posture

Mode of action of DNA-competitive small molecule inhibitors of tyrosyl DNA phosphodiesterase 2

TDP2 is a 5’-tyrosyl DNA phosphodiesterase important for the repair of DNA adducts generated by non-productive (abortive) activity of topoisomerase II. TDP2 facilitates therapeutic resistance to topoisomerase poisons, which are widely used in the treatment of a range of cancer types. Consequently, TDP2 is an interesting target for the development of small molecule inhibitors that could restore sensitivity to topoisomerase-directed therapies. Previous studies identified a class of deazaflavin-based molecules that showed inhibitory activity against TDP2 at therapeutically useful concentrations, but their mode of action was uncertain. We have confirmed that the deazaflavin series inhibits TDP2 enzyme activity in a fluorescence-based assay, suitable for HTS-screening. We have gone on to determine crystal structures of these compounds bound to a ‘humanised’ form of murine TDP2. The structures reveal their novel mode of action as competitive ligands for the binding site of an incoming DNA substrate, and point the way to generating novel and potent inhibitors of TDP2