Visual requirements analytics: a framework and case study

For many software projects, keeping requirements on track needs an effective and efficient path from data to decision. Visual analytics creates such a path that enables the human to extract insights by interacting with the relevant information. While various requirements visualization techniques exist, few have produced end-to-end value to practitioners. In this paper, we advance the literature on visual requirements analytics by characterizing its key components and relationships in a framework. We follow the goal–question–metric paradigm to define the framework by teasing out five conceptual goals (user, data, model, visualization, and knowledge), their specific operationalizations, and their interconnections. The framework allows us to not only assess existing approaches, but also create tool enhancements in a principled manner. We evaluate our enhanced tool support through a case study where massive, heterogeneous, and dynamic requirements are processed, visualized, and analyzed. Working together with practitioners on a contemporary software project within its real-life context leads to the main finding that visual analytics can help tackle both open-ended visual exploration tasks and well-structured visual exploitation tasks in requirements engineering. In addition, the study helps the practitioners to reach actionable decisions in a wide range of areas relating to their project, ranging from theme and outlier identification, over requirements tracing, to risk assessment. Overall, our work illuminates how the data-to-decision analytical capabilities could be improved by the increased interactivity of requirements visualization.     

Injectable Platelet-Rich Fibrin as a Drug Carrier Increases the Antibacterial Susceptibility of Antibiotic—Clindamycin Phosphate

The aim of this study was to investigate the change in clindamycin phosphate antibacterial properties against Gram-positive bacteria using the platelet-rich fibrin as a carrier matrix, and evaluate the changes in the antibiotic within the matrix. The antibacterial properties of CLP and its combination with PRF were tested in a microdilution test against reference cultures and clinical isolates of Staphylococcus aureus (S. aureus) or Staphylococcus epidermidis (S. epidermidis). Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analysis was done to evaluate the changes in the PRF_CLP matrix. Release kinetics of CLP was defined with ultra-performance liquid chromatography (UPLC). According to FTIR data, the use of PRF as a carrier for CLP ensured the structural changes in the CLP toward a more active form of clindamycin. A significant decrease in minimal bactericidal concentration values (from 1000 µg/mL to 62 µg/mL) against reference cultures and clinical isolates of S. aureus and S. epidermidis was observed for the CLP and PRF samples if compared to pure CLP solution. In vitro cell viability tests showed that PRF and PRF with CLP have higher cell viability than 70% after 24 h and 48 h time points. This article indicates that CLP in combination with PRF showed higher antibacterial activity against S. aureus and S. epidermidis compared to pure CLP solution. This modified PRF could be used as a novel method to increase drug delivery and efficacy, and to reduce the risk of postoperative infection.     

Investigation of buoyancy-driven flow and heat transfer in a trapezoidal cavity filled with water–Cu nanofluid

A numerical study is conducted to investigate the transport mechanism of free convection in a trapezoidal enclosure filled with water–Cu nanofluid. The horizontal walls of the enclosure are insulated while the inclined walls are kept at constant but different temperatures. The numerical approach is based on the finite element technique with Galerkin's weighted residual simulation. Solutions are obtained for a wide range of the aspect ratio (AR) and Prandtl number (Pr) with Rayleigh number (Ra = 10⁵) and solid volume fraction (? = 0.05). The streamlines, isotherm plots and the variation of the average Nusselt number at the left hot wall are presented and discussed. It is found that both AR and Pr affect the fluid flow and heat transfer in the enclosure. A correlation is also developed graphically for the average Nusselt number as a function of the Prandtl number as well as the cavity aspect ratio.     

A novel fault ride-through technique for grid-connected Photo Voltaic energy systems

In this article, a novel fault ride-through technique has been implanted with a double control loop method. This method is implemented with voltage-source converters, where the active and reactive power could be easily done with the voltage control loop and inherent current control loop. The proposed system has been implemented to grid-connected photovoltaic systems, and the results have been explored and compared with the existing techniques. An additional control strategy is implemented successfully for satisfactory performance of the system during low irradiance periods, and the system is made capable to provide Q-support to the grid according to the system operators request with the help of Q-set point.     

Low‐temperature synthesis of nanocrystalline hydroxyapatite: Effect of Mg and Sr content

Nanocrystalline Mg‐ or Sr‐containing hydroxyapatite powders were synthesized through low‐temperature chemical precipitation. The most significant factor for reduction in particle sizes included adjusting the reaction temperature between 0°C and 50°C. Syntheses products were characterized using several analytical tools to determine purity and influence of added amount (up to 15 mol%) of Mg or Sr on the composition and structure. Qualitative analysis by Fourier transform infrared spectroscopy and low intensity, broad X‐ray diffraction peaks indicated the presence of nanocrystalline and/or amorphous hydroxyapatite in all the products. Moreover, a significant decrease in the crystallinity was observed with increasing Mg (up to 2.8 ± 0.3 wt%) and Sr (up to 9.6 ± 1.0 wt%) concentration. N₂ adsorption and scanning electron microscopy characterizations confirmed the nanocrystalline nature of the synthesized products. The synthesized products had nanosized spherical‐like particle morphology with the specific surface area ranging from 89 ± 7 to 150 ± 20 m²/g.     

Novel derivatives of 3D woven T-shaped composites with improved performance

Conventional 3D woven T-shaped preforms were modified for improving joint/ peel off strength of associated T-shaped polymeric composites. Preforms were modified at weaving level by preferred yarns orientations for better performance in associated composites. Major modifications studied are; the addition of supporting layer, single or double-crossing in joint layers and crossing along with supporting layer (in a single sample). Novel derivatives were compared with conventionally used (on-loom and off-loom) T-shaped 3D woven composites. Microscopic analysis was also carried out to analyze the orientation of yarns and analysis of samples from failure point after testing. By combined variation of crossing and supporting layers improvement of 47.37% in peel off strength and 70.37% in impact strength was observed. Modified T shapes can serve to be a good replacement for conventional T-shaped stiffener (used to avoid folding under loads) and in joints.     

Synthesis and characterization of completely soluble and highly thermally stable PANI-DBSA salts

This paper presents synthesis and characterization of soluble polyaniline-dodecylbenzenesulfonic acid (PANI-DBSA) via inverse polymerization. A mixture of chloroform and 2-butanol was used as dispersion medium for the first time. This polymerization pathway leads to the formation of PANI-DBSA salts which are completely soluble in a number of common organic solvents (such as DMSO, DMF, chloroform and in a mixture of toluene) and 2-propanol (so far highest number of solvents for solubility of PANI). The influence of synthesis parameters such as concentration of aniline, benzoyl peroxide and dodecylbenzenesulfonic acid (DBSA) on the yield and other properties of the resulting PANI-DBSA salts was studied. Further characterization of the synthesized materials was done with the help of viscosity measurements, UV–Vis spectroscopy, cyclic voltammetry, XRD and SEM. TGA was used to analyze the thermal properties of synthesized polymer. The synthesized salts were found to be highly stable.