VoIP on 3GPP LTE Network: A Survey

As wireless access networks evolve towards an all-IP architecture, the principles of operations of communication services (specifically voice services), which have hitherto been circuit switched are being revisited. Voice over Internet Protocol (VoIP) has been identified as a solution and is potentially capable of completely replacing existing phone networks.  However, as opposed to circuit switching technology, the call quality obtained via packet switching through IP has not been encouraging due to certain issues. The increasing demands on data rates, mobility, coverage and better service quality, led to the evolution in Radio Access Technologies (RATs) to an era of last-mile fourth generation (4G) access technologies among which is Long Term Evolution (LTE). LTE is an all-IP network initially meant for carrying data only, while carriers would be able to support voice traffic either by utilizing 2G or 3G systems or by using VoIP. This paper seeks to describe all options for providing VoIP services as a method of voice transfer over the LTE network. Keywords: 4G, Circuit switching, Convergence, LTE, Packet switching, RAT, VoIP

A Simplified Overview of Text-To-Speech Synthesis

Computer-based Text-To-Speech systems render text into an audible form, with the aim of sounding as natural as possible. This paper seeks to explain Text-To-Speech synthesis in a simplified manner. Emphasis is placed on the Natural Language Processing (NLP) and Digital Signal Processing (DSP) components of Text-To-Speech Systems. Applications and limitations of speech synthesis are also explore

A Performance Review of the Different Path Loss Models for LTE Network Planning

Long Term Evolution also called release 8, the 3GPP successor of UMTS, has brought about higher data rates, spectrum flexibility as a result of its TDD and FDD. The concept of path loss and network planning are very important to deployment of telecommunications. Path loss models are used in the initial feasibility studies in telecommunications deployment. In this paper, a comparative analysis of the five path loss models used in LTE networks was simulated using a MATLAB-based simulator; LTE MAC-LAB developed by is-wireless Poland

Application of best estimate plus uncertainty in review of research reactor safety analysis

To construct and operate a nuclear research reactor, the licensee is required to obtain the authorization from the regulatory body. One of the tasks of the regulatory authority is to verify that the safety analysis fulfils safety requirements. Historically, the compliance with safety requirements was assessed using a deterministic approach and conservative assumptions. This provides sufficient safety margins with respect to the licensing limits on boundary and operational conditions. Conservative assumptions were introduced into safety analysis to account for the uncertainty associated with lack of knowledge. With the introduction of best estimate computational tools, safety analyses are usually carried out using the best estimate approach. Results of such analyses can be accepted by the regulatory authority only if appropriate uncertainty evaluation is carried out. Best estimate computer codes are capable of providing more realistic information on the status of the plant, allowing the prediction of real safety margins. The best estimate plus uncertainty approach has proven to be reliable and viable of supplying realistic results if all conditions are carefully followed. This paper, therefore, presents this concept and its possible application to research reactor safety analysis. The aim of the paper is to investigate the unprotected loss-of-flow transients "core blockage" of a miniature neutron source research reactor by applying best estimate plus uncertainty methodology. The results of our calculations show that the temperatures in the core are within the safety limits and do not pose any significant threat to the reactor, as far as the melting of the cladding is concerned. The work also discusses the methodology of the best estimate plus uncertainty approach when applied to the safety analysis of research reactors for licensing purposes

Analysis of root growth from a phenotyping data set using a density-based model

Major research efforts are targeting the improved performance of root systems for more efficient use of water and nutrients by crops. However, characterizing root system architecture (RSA) is challenging, because roots are difficult objects to observe and analyse. A model-based analysis of RSA traits from phenotyping image data is presented. The model can successfully back-calculate growth parameters without the need to measure individual roots. The mathematical model uses partial differential equations to describe root system development. Methods based on kernel estimators were used to quantify root density distributions from experimental image data, and different optimization approaches to parameterize the model were tested. The model was tested on root images of a set of 89 Brassica rapa L. individuals of the same genotype grown for 14 d after sowing on blue filter paper. Optimized root growth parameters enabled the final (modelled) length of the main root axes to be matched within 1% of their mean values observed in experiments. Parameterized values for elongation rates were within ±4% of the values measured directly on images. Future work should investigate the time dependency of growth parameters using time-lapse image data. The approach is a potentially powerful quantitative technique for identifying crop genotypes with more efficient root systems, using (even incomplete) data from high-throughput phenotyping systems

The Macroeconomic Effect of Minimum Wage Increase in Nigeria: A DSGE Approach

The minimum wage is an economic policy tool aimed at raising the earning of low-income households with the ultimate objective to improve the living standard of these group of workers. Nigeria, has over time, enacted four national minimum wage acts. The most recent is the Minimum Wage Repeal and Enactment Act 2019 which has increased the minimum payment to workers from N18, 000 to N30, 000, representing a surge of about 66.67 per cent. Upon implementation of this new bill, it is expected to have varying macroeconomic effects ranging from wage effects, employment effects, distributional effects, welfare effects and price effects among others. This study, therefore examines the macroeconomic effects of the four episodes of the minimum wage increase in Nigeria by calibrating and log-linearising a New Keynesian Dynamic Stochastic General Equilibrium (DSGE) model that is extended to include labour heterogeneity. The study found that minimum wage increase does not improve household welfare and living standard neither does it have any positive growth effect. Furthermore, it strains government finances. The implication of the finding is that minimum wage policy shouldbe complemented with other pro-poor and inclusive development policies in order to improve the quality of life for the poor and vulnerable low income worker

Assessing Georgia Consumer Attitudes and Beliefs about Locally or Regionally Produced Livestock and Products

Abstract Interest in local and regional food production has been growing in the last few years. The study, therefore, assessed consumer attitudes and beliefs regarding local or regional livestock products. Data were obtained from a convenience sample of 384 participants from several counties of Georgia, and were analyzed by descriptive statistics, including chi-square tests. A majority of respondents thought using chemicals and additives in locally or regionally produced beef or goat meat was a serious or somewhat serious hazard. Consequently, many were willing to pay more for meat certified as locally or regionally produced. Furthermore, a majority agreed or strongly agreed with statements on meat attributes, such as affordability and quality. Chi-square tests showed that race/ethnicity and education had significant relationships with willingness to pay more for meat certified as locally or regionally produced. Additionally, safety, availability, quality, desirability, and hygiene had significant relationships with willingness to pay more for meat certified as locally or regionally produced. Keywords: Consumers, Attitudes and Beliefs, Local or Regional, Willingness to Pay, Livestock Product

A Comparative Analysis of Selected Producer Characteristics and Production Practices of Small Livestock Producers in Three Southeastern States of The US

It is germane to know the characteristics and practices of small livestock producers in order to assist them; however, there are a paucity of investigations on the subject in the Southeastern US. Thus, this study assessed selected producer characteristics and production practices of small livestock producers in three Southeastern States. The data were collected from three samples of producers in several counties of Alabama, Georgia, and Florida, and were analyzed using descriptive statistics. The results showed that, a majority of producers practiced rotational grazing, had parasite problems, quarantined newly acquired animals, and used veterinary services. Additionally, a majority sold their animals live, and many kept records manually or on a computer. The findings indicate commonalities across the three states, in terms of rotational grazing, parasite problems, quarantine, how animals are sold, and record keeping. There is a need to assist small producers in certain aspects of production practices and in value-added processe

Influence of crop residue ration supplementation on the attainment of puberty and postpartum reproductive activities of Red Sokoto goats

The general objective of this study was to come up with an appropriate, affordable and locally available crop residue supplementation package that would enhance reproductive performance in small ruminants. Specifically, 28 Red Sokoto weaner does between 3 and 4 months of age weighing between 2 and 3 kg were used in the first experiment to determine the influence of crop residue supplementation on age and weight at puberty as determined by blood progesterone levels. In the second experiment, another 28 adult does (equal to or greater than 2 years old) of the same breed in the same flock with lactation numbers between 1 and 3 were used to determine the length of postpartum acyclic period. In both experiments, a 3 x 2 factorial experimental design comprising three dietary supplements (A, B, C) at two feeding levels (1% and 2% of body weight) fed in addition to a basal diet of Digitaria smutsii hay and natural pasture ad libitum with an unsupplemented negative control group (D) and four goats per treatment was utilized. In ration A, a conventional concentrate supplement consisting of maize, wheat offal, cottonseed cake and bonemeal was utilized; in rations B and C, the supplement consisted of guinea-corn bran, cowpea husk and groundnut haulms; and maize offal, groundnut shells and groundnut haulms respectively. Unsupplemented (ration D) weaner does reached puberty at a later age and had lighter body weights than all the others. Weaner does on ration 2A (concentrate fed at 2% of body weight) attained puberty at the earliest age and heaviest body weight, although the age at puberty was not significantly different from those on rations 1A (concentrate fed at 1% body weight), 1C and 2C. Blood progesterone profiles before and after puberty ranged from 0.05 to 9.0 ng/ml, respectively, and was highest in does fed rations A and C and least in the unsupplemented does. The mean interval between kidding and initiation of ovarian activity was 54.28 plus or minus 17.61 days and the mean interval between kidding and conception was 63.04 plus or minus 25.34 days. Only 25% of the unsupplemented does conceived again during the period under study compared with 100% in rations 1A, 2A, 1C and 2C; 75% in ration 2B and 50% in ration 1B. It was concluded that implementation of supplementary feeding in the dry season improves reproductive performance in the Red Sokoto doe. Furthermore, ration C, a crop residue-based ration, was a suitable dry season supplementation alternative to the expensive conventional concentrate ration for the smallholder goat farmer in the subhumid tropics of Nigeria