On OSTBC Codes for LTE-A Systems-Design and Performance Evaluation

Long Term Evolution-Advanced (LTE-A) is a Fourth Generation (4G) standard of wireless communications that introduces high data rate, high performance, and low delay. These features of LTE-A resulted from the new techniques developed for wireless communications such as Multiple-Input Multiple-Output (MIMO) technique. At the heart of this technique is the Space Time Codes, which were developed by the researchers in recent decades to achieve the mentioned features. The designs of OSTBC codes for MIMO systems having any number of transmit antennas and any number of receive antennas have attracted the attention of many researchers. Based on the theory of real and complex orthogonal designs, this paper deals with the design of real and complex OSTBC codes to be used with real signal set constellation such PAM and complex signal constellation such as PSK and QAM. Real and complex OSTBC codes for MIMO systems with two, three, four, five, six, seven and eight transmit antennas and any number of receive antennas, are presented. Simple linear processing ML decoders are derived and presented. The used channel is Rayleigh fading channel MIMO and assumed to behave in a “quasi-static” fashion. Finally, the performances of OSTBC schemes were evaluated and compared in terms of the Bit Error Rate (BER) and Signal to Noise Ratio (SNR). The environment of simulation is MATLAB which is a powerful tool for mathematical calculation and system simulation. The methods of modulations chosen are QPSK, 16QAM, 64QAM, and 128QAM with gray scale mapping

Assessment of Calotropis natural dye extracts on the efficiency of dye-sensitized solar cells

ArticleThis work presents the construction and testing of solar cells sensitized with natural dyes extracted from plants indigenous to the desert. Calotropis plants are self - sufficient as they grow in very harsh environments, and yet are not consumed by humans or livestock due to their irritating agents to the skin and eyes. The energy generators of these plants are the leaves, which are crushed and processed to produce the dye solution. Also, the Calotropis leaves are covered in a white powder that is thought to aid in mitigating the heat by scattering incident radiation. This powder material is examined and added to the dye as it proved advantageous for the o verall cell efficiency, which reached 0.214% compared with 0.108% for cells with no powder. The produced cells are also compared with ones sensitized by spinach, another common natural sensitizer for dye - sensitized solar cells, and the performance proved t o be significantly better. The fact that Calotropis is a non - food plant is an added advantage to utilizing it as a dye source, along with its intrinsic heat resistance that allows it to survive the harsh desert conditions all year round

The effects of free amino acids profiles on seeds germination/dormancy and seedlings development of two genetically different cultivars of Yemeni Pomegranates

Plant seeds used rely on a wide range of internal mechanisms and physio-chemical factors to ensure their germination under favorable environmental conditions. Most plant seeds have complex process of germination, including water, oxygen, temperature availability, genome-wide gene expression, signal transduction, hormones stimulations, inhibitors removal and catalytic protein synthesis. In addition, influences of seeds nutrient values such as, protein, lipids, sugars and free amino acids have a special importance. Regarding, seeds free amino acids. Discussion of these individual factors needs to be put in context of their role in germination processes. Regarding, free amino acids seed storage, there is limited information about their relevant functions in activation and/or deactivation of required metabolic mechanisms and interactive compounds involved in this process in commercial plant cultivars. Therefore, current study was aimed to determine the probable influence of free amino acid compositions of seeds on germination process of two different (Punica granatum L.) pomegranate cultivars including wild type Automi cultivar and edible Khazemi cultivar. In particular, we focused on the impact of amino acids contents variations on germination process and associated AAs compositional changes during various stages of germination and seedlings establishment. Amino acid analysis using HPLC detected all the essential and non-essential amino acids in the raw seeds of the studied cultivars, Automi and Khazemi along with AAs compositional changes occurred during different stages of seed germination. These AAs have been extensively analyzed in the context of their role in dormancy breaking capacities in plants species. Automi raw seeds are rich in Phe, that, is strongly related to ABA synthesis and hence might be responsible for the dormancy of Automi seeds, Khazemi raw seeds have sufficient levels of Arg, Glu and Met that have been reported to enhance seeds germination in plant, therefore Khazemi germination capacity was assumed to be regulated more or less by these AAs. In addition, changes in amino acid composition in the germinated Khazemi cultivar during various stages of seeds germination including imbibition, germination, and sprouts stages have been noticed to change in response with germination demands. This suggests that amino acids reserves in dry seeds are major determinant for germination capacity and germination behavior in the following steps of germination. The noticed particular AAs increase/decrease along the time course of Khazemi pomegranate germination till establishment of heterotrophic seedlings were used as cornerstones for elucidation and deduction of putative function and relevant biochemical pathways controlling initiation of seeds germination and seedlings developments. Based on publicly available databases of model plants and literatures surveys, we established correlations between prevailing AAs factors as biochemical parameters actively involved in seeds dormancy-breaking and germination process

Effects of different types of RSS data on the system accuracy of indoor localization system

Indoor localization system becomes a substantial issue in recent research, especially in terms of the accuracy. Location based services have been used in many mobile applications as well as wireless sensor networks. High accuracy and fast convergence are very important issues for a good localization system. However, the type of obtained received signal strength (RSS) data is very important in order to get high accuracy. In this paper, we introduce three types of RSS data, which are: measured RSS, simulated RSS and average combined RSS. Bayesian network based on fingerprinting technique is used to investigate the effect of the three different types of RSS. The results show the effect of the three different RSS data on the accuracy of estimated location. The measured RSS has achieved an average accuracy of 4.3 meters using 10 training points while the average combined RSS has achieved a good accuracy of 2.1 meters

Robust 3D indoor positioning system based on radio map using Bayesian network

Indoor positioning remains a serious issue due to the difficulty in attaining sufficient accuracy within an indoor environment using tracking technology of low complexity. Currently, most positioning systems do not embed the off-the-shelf (OTS) system which allows mobile devices to estimate location without using any additional hardware. In this paper, we propose a robust 3D indoor positioning system that is suitable for an indoor IoT application. This system based on Bayesian network that depends on Wi-Fi signals strength. It was experimentally tested in a building with pre-deployed access points (APs). The experimental results indicate that localization accuracy of the proposed system is high with the use of a small-sized radio map

Simulation and experimental analysis of indoor localization systems

Indoor localization systems, especially its accuracy, have become a major topic in recent research. Moreover, location-based services have been used in many mobile applications and wireless sensor networks. High accuracy and fast convergence are crucial requirements for a good localization system. However, the type of obtained received signal strength (RSS) data is vital to obtain high accuracy. In this paper, we perform a simulation and an experimental analysis for an indoor localization system. Moreover, 2D and 3D localization models are considered to investigate the localization error. The simulation is developed to provide an accurate RSS compared with an experimental testbed by considering the multiwall path loss model. Results demonstrate that the simulated RSS data are consistent with the experimental RSS data; that is, the simulated data almost have same distribution form as the experimental data. Therefore, the simulation can be used to develop high-accuracy localization systems

Data mining in higher education

Data mining is slowly but surely making its way into the educational field after dominating the business fields.  This paper focuses on the research completed in the area of data mining in the higher education sector: colleges and universities.  We will look at the different implementation of data mining and to what extent was it utilized and benefited from

Modeling the causes and mitigation measures for cost overruns in building construction : The case of higher education projects

The formidable need for building projects places greater pressure on stakeholders to deliver these projects on time, within the budget, and with high quality. However, many building projects have experienced extensive cost overruns despite extensive research on their causes and mitigation measures. Thus, the effectiveness of mitigation measures is questionable. This study examines the status of cost overrun in building construction projects and develops a structural equation model to establish the relationships between causes of cost overrun and mitigation measures, using higher education building projects as a case study. This study analyzed cost overruns in 27 higher education building projects. Furthermore, 118 responses were collected using a questionnaire survey and analyzed using descriptive statistics, the Kruskal–Wallis H test, exploratory factor analysis, and partial least-squares structural equation modeling (PLS-SEM). The findings suggest that around 93% of the 27 higher education building projects experienced cost overrun, and the majority overran between 5% and 10%. The findings illustrate that bid evaluation and project planning mitigation measures positively affect efficiency and contract management- and design-related causes. Furthermore, project initiation and contractor selection mitigation measures positively affect claim management-, efficiency and contract management-, estimation and scheduling-, and design-related causes. These findings will help policymakers make informed decisions in selecting effective mitigation measures to reduce cost overrun and improve industry efficiency

Sponge media drying using a swirling fluidized bed dryer

Surface preparation today has seen the introduction of sponge media as an alternative product against the traditionally used abrasive materials. Being soft and elastic, the sponge media reduces air borne emission significantly during surface preparation with capability to be re-used. However the environmental conditions limit the sponge media usage whereby wet surroundings prohibit the re-use of the sponge without being dried properly. This study proposes the swirling fluidized bed dryer as a novel drying technique for sponge media. Batch experiments were conducted to study the bed’s hydrodynamics followed by drying studies for three bed loadings of 0.5 kg, 0.75 kg and 1.0 kg at three drying temperatures of 80°C, 90°C and 100°C. It was found that, minimum fluidization velocities for the wet sponge particles were found to be 1.342, 1.361 and 1.382 m/s with minimum swirling velocities of 1.400, 1.469 and 1.526 m/s. Drying times were recorded between 6 to 16 minutes depending on bed loading and drying temperature. Smaller bed weights exhibits faster drying with constant-rate drying period while higher drying temperature and larger bed load resulted in falling-rate drying period. Thin layer modelling for the falling-rate region indicates that Verma et. al model provides the best fit for the present experimental data with coefficient of determination, R2 = 0.98773, root mean square error, RMSE = 0.05048, residuals = 0.3442 and reduced chi-square, χ2 = 0.00254. The effective diffusivity, Deff, for 0.5 kg bed load was found to be 3.454 x 10-9 m2/s and 1.751 x 10-9 m2/s for 0.75 kg bed load. In conclusion, SFBD was found to be a viable and efficient method in drying of sponge media for various industrial applications particularly surface preparation

A new indoor localization system based on Bayesian graphical model

Indoor localization techniques that use wireless local area network beacon signals have recently gained considerable attention among research communities. System accuracy is one of the most important issues in indoor localization technology. We propose a Bayesian graphical model based on fingerprinting location algorithm in this study. The proposed Bayesian model was simulated using OpenBUGS, a graphical user interface. We conducted an experiment to collect a sample of reference points in a testbed with a dimension of 51 × 22 m 2 . Results show that the proposed model has improved the accuracy by 25.65% using 15 reference points compared with Madigan model