Correction to: Deposition of bismuth sulfide and aluminum doped bismuth sulfide thin films for photovoltaic applications

Journal of Materials Science: Materials in Electronics -     

A Comparative Analysis of RAD and Agile Technique for Management of Computing Graduation Projects

Computing students face the problem with time and quality of the work while managing their graduation/senior projects. Rapid Application Development (RAD) model is based on continual user involvement for the process of requirement gathering via prototyping. After each iteration, the developers can validate the requirements that are completed in the iteration. Managing a project with RAD is easier but not flexible. On the other hand, Agile project management techniques focus on flexibility, agility, teamwork and quality based on user stories. Continual user involvement is avoided, which requires extensive maintenance time for fixing iteration and release of the story points. This also makes it necessary to provide onsite training to the users of the application. This research provides the pros and cons of RAD and Agile project management techniques, to help students in deciding the best approach for managing their graduation projects. For the evaluation of these techniques, similar case studies were given to the senior project students (having similar CGPAs) for building similar functionality-based applications. The two projects “Life Organizer” developed and managed using RAD and “Smart Patient Assistant (SPA)” developed and managed through Agile methodology were evaluated against the quality assurance criteria for senior projects. The study found that the project developed with RAD methodology performed 13.33% better in providing extensive and elaborated documentation than the students following the Agile technique. On the other hand, SPA-Agile based project, due to teamwork had 2.5% better implementation than Life Organizer-RAD based project.     

Stimulation of secondary metabolites by copper and gold nanoparticles in submerge adventitious root cultures of Stevia rebaudiana (Bert.)

Nanotechnology is one of the advance technologies that almost found implications in every field of science. The importance is due to the unique properties of nanoparticles. In this study, bimetallic alloys of copper (Cu) and gold (Au) were tested in submerge root cultures of Stevia rebaudiana for production of biomass and secondary metabolites. A known amount of inoculum roots were submerged in liquid Murashige and Skoog medium containing combination of naphthalene acetic acid (NAA; 0.5 mg l⁻¹) and different ratios of nanoparticles (NPs). NAA augmented medium was used as control. The addition of nanoparticles (30 µg l⁻¹) stimulated biomass accumulation (1.447 g/flask) on 27th day of log phases. The maximum total phenolics content (TPC; 16.17 mg/g‐DW) and total flavonoids content (TFC; 4.20 mg/g‐DW) were displayed using AuCu‐NPs (1:3) and NAA. The same combinations enhanced total phenolic production (TPP; 116 mg/L) and total flavonoid production (TFP; 29.5 mg/L) in submerged cultures. A strong correlation was observed between phenolics, flavonoids and dry biomass. Moreover, maximum 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH) activity of 79% was displayed by addition of AuCu (1:3) nanoparticles. In conclusion, nanoparticles application has shown a positive effect in enhancing biomass and secondary metabolites production in adventitious root cultures of Stevia rebaudiana.Inspec keywords: bimetals, copper, gold, nanoparticles, renewable materials, bioenergy conversion, toxicology, nanofabrication, nanobiotechnology, biochemistry, molecular biophysicsOther keywords: Au‐Ag, time 27 d, maximum DPPH activity, dry biomass, flavonoids, phenolics, NAA enhanced total phenolic production, total flavonoid content, maximum total phenolic content, log phases, bimetallic NPs stimulated biomass accumulation, NAA augmented medium, naphthalene acetic acid, Skoog medium, liquid Murashige, inoculum roots, culture development, seed‐derived roots, bimetallic alloys, nanotechnology, Stevia rebaudiana (Bert.), submerge adventitious root cultures, gold nanoparticles, copper nanoparticles, secondary metabolites     

Cascaded neural network based small array synthesis with robustness to noise

A cascaded neural network approach has been presented in this paper to estimate the excitation for the desired field distribution using a radial basis function neural network (RBFNN). The article has employed an electromagnetic design example consisting of 5 × 5 and 6 × 6 planar antenna array of isotropic sources with inter element‐distance of 0.5λ to show the adaptation of the neural network model in estimating the desired output. A neural network is trained using a dataset of suitable excitation voltages and its corresponding radiation patterns, which proves to be efficient in predicting the excitation voltages required to generate the desired pattern. A set of techniques based on a cascaded neural network is adopted for pattern synthesis using magnitude and phase, magnitude only, and template‐based input data. The robustness of the method has also been tested by considering noise with different SNR levels. The results found in each case have a close fit with the desired pattern.     

A pitch synchronous approach to design voice conversion system using source-filter correlation

We propose a pitch synchronous approach to design the voice conversion system taking into account the correlation between the excitation signal and vocal tract system characteristics of speech production mechanism. The glottal closure instants (GCIs) also known as epochs are used as anchor points for analysis and synthesis of the speech signal. The Gaussian mixture model (GMM) is considered to be the state-of-art method for vocal tract modification in a voice conversion framework. However, the GMM based models generate overly-smooth utterances and need to be tuned according to the amount of available training data. In this paper, we propose the support vector machine multi-regressor (M-SVR) based model that requires less tuning parameters to capture a mapping function between the vocal tract characteristics of the source and the target speaker. The prosodic features are modified using epoch based method and compared with the baseline pitch synchronous overlap and add (PSOLA) based method for pitch and time scale modification. The linear prediction residual (LP residual) signal corresponding to each frame of the converted vocal tract transfer function is selected from the target residual codebook using a modified cost function. The cost function is calculated based on mapped vocal tract transfer function and its dynamics along with minimum residual phase, pitch period and energy differences with the codebook entries. The LP residual signal corresponding to the target speaker is generated by concatenating the selected frame and its previous frame so as to retain the maximum information around the GCIs. The proposed system is also tested using GMM based model for vocal tract modification. The average mean opinion score (MOS) and ABX test results are 3.95 and 85 for GMM based system and 3.98 and 86 for the M-SVR based system respectively. The subjective and objective evaluation results suggest that the proposed M-SVR based model for vocal tract modification combined with modified residual selection and epoch based model for prosody modification can provide a good quality synthesized target output. The results also suggest that the proposed integrated system performs slightly better than the GMM based baseline system designed using either epoch based or PSOLA based model for prosody modification.     

Synthesis and modification of silica-based epoxy nanocomposites with different sol–gel process enhanced thermal and mechanical properties

This research article describes the results of nano-silica composites filled with different epoxy contents containing nano-SiO₂ particles from (5–25 wt%). Reinforcing hybrid composites enhance thermal and mechanical properties to achieve vital and sustainable products. Silica-based nanocomposites with high purity were prepared and used for the surface modification of nanosized silica particles. The surface structure's composition and physical properties of modified nano-SiO₂ particles were characterized through Fourier transferred infrared spectrometer, X-ray photoelectron spectroscopy, thermogravimetric analyzer, and scanning electron microscopic. Silica-based nanocomposites were prepared by incorporating of modified nano-SiO₂ as an enhancing filler. The morphology of fracture surface and dynamic mechanical properties were investigated. Results showed that the silica-based epoxy nanocomposites are bearing a long chain structure that could improve the compatibility of silica nanocomposites with epoxy resin and contribute to a better dispersion state in the matrix, which enhanced the overall performance of epoxy-cured products.     

Compatibility of automotive materials in biodiesel: A review

Use of biodiesel in automobile can significantly reduce our dependence of fossil fuel and help reduce environmental pollution. However, there are concerns over the compatibility of currently used automotive materials in biodiesel. A few automobile manufacturers extended their warranty only to lower blends of biodiesel (e.g. B5). Higher blends (e.g. B50 or B100) are still not covered by warranty. In automobile fuel system, metallic materials like ferrous alloy and non-ferrous alloys, and elastomers come in contact with fuel. Biodiesel, having different chemical characteristics from diesel, can interact with materials in a different way. It can cause corrosive and tribological attack on metallic components and degrade elastomer parts. This paper attempts to present an overview of the work done so far on the compatibility of biodiesel with automotive materials.     

Conduction mechanisms and thermoelectric applications of La1-xSrxCoO3 nanofibers

Journal of Materials Science - Single-phase La1-xSrxCoO3 (x?=?0, 0.01, 0.03, 0.05, 0.07, and 0.1) nanofibers were synthesized via electrospinning technique. Different characterization...     

Reverse Engineering of Mobile Banking Applications

Software reverse engineering is the process of analyzing a software system to extract the design and implementation details. Reverse engineering provides the source code of an application, the insight view of the architecture and the third-party dependencies. From a security perspective, it is mostly used for finding vulnerabilities and attacking or cracking an application. The process is carried out either by obtaining the code in plaintext or reading it through the binaries or mnemonics. Nowadays, reverse engineering is widely used for mobile applications and is considered a security risk. The Open Web Application Security Project (OWASP), a leading security research forum, has included reverse engineering in its top 10 list of mobile application vulnerabilities. Mobile applications are used in many sectors, e.g., banking, education, health. In particular, the banking applications are critical in terms of security as they are used for financial transactions. A security breach of such applications can result in huge financial losses for the customers as well as the banks. There exist various tools for reverse engineering of mobile applications, however, they have deficiencies, e.g., complex configurations, lack of detailed analysis reports. In this research work, we perform an analysis of the available tools for reverse engineering of mobile applications. Our dataset consists of the mobile banking applications of the banks providing services in Pakistan. Our results indicate that none of the existing tools can carry out the complete reverse engineering process as a standalone tool. In addition, we observe significant differences in terms of the execution time and the number of files generated by each tool for the same file.     

Design and development of ceramic-based composites with tailored properties for cutting tool inserts

A successful approach to the development of tailored cutting tool materials requires the development of innovative concepts at each step of manufacturing, from the material design, synthesis of composite powders, to their processing and sintering. In this paper, a computational design approach is applied in the development of reinforced ceramic-based cutting tool inserts with tailored structural and thermal properties. Several potential filler materials are considered at the material design stage for the improvement of structural and thermal properties of a selected matrix material. Properties, such as an improved thermal conductivity and reduced coefficient of thermal expansion are essential for an effective cutting tool insert to absorb thermal shock at varying temperatures. In addition, structural properties such as elastic modulus have to be maintained within a moderate range. A mean-field homogenization theory and effective medium approximation using an in-house code are applied for predicting potential optimum structural and thermal properties for the required application. This is done by considering the effect of inclusions as a function of volume fraction and particle size in the ceramic base matrix. Single inclusion composites such as alumina-silicon (Al₂O₃-SiC) and alumina-cubic boron nitride (Al₂O₃-cBN) as well as hybrid composite such as alumina-silicon-cubic boron nitride (Al₂O₃-SiC-cBN) are developed using the Spark Plasma Sintering (SPS) process in line with the designed range of filler size and volume fraction to validate the computational results. It is found that the computational material design approach is precise enough in predicting the target properties of a designed hybrid composite material for cutting tool inserts.