Using DevOps toolchains in Agile model-driven engineering

For model-driven engineering (MDE) to become more Agile, the community needs to embrace development and operations (DevOps) practices. One of the core practices of DevOps is the use of pipelines to enable CI/CD to make teams more Agile and break down the barriers between development and operations with faster deployments. Current MDE tooling is not designed at its core to participate in DevOps pipelines. Consequently this makes the adoption of MDE in industry more difficult. In this article, we cover an industrial experience report describing how we enabled our pipelines using DevOps and MDE.

     

Establishing stable time‐steps for DEM simulations of non‐collinear planar collisions with linear contact laws

The discrete element method, developed by Cundall and Strack, typically uses some variations of the central difference numerical integration scheme. However, like all explicit schemes, the scheme is only conditionally stable, with the stability determined by the size of the time‐step. The current methods for estimating appropriate discrete element method time‐steps are based on many assumptions; therefore, large factors of safety are usually applied to the time‐step to ensure stability, which substantially increases the computational cost of a simulation. This work introduces a general framework for estimating critical time‐steps for any planar rigid body subject to linear damping and forcing. A numerical investigation of how system damping, coupled with non‐collinear impact, affects the critical time‐step is also presented. It is shown that the critical time‐step is proportional to if a linear contact model is adopted, where m and k represent mass and stiffness, respectively. The term which multiplies this factor is a function of known physical parameters of the system. The stability of a system is independent of the initial conditions. © 2016 The Authors. International Journal for Numerical Methods in Engineering Published by John Wiley & Sons Ltd.     

Analytical study of the accuracy of discrete element simulations

The numerical errors was used to verify the correctness of key results. The truncation errors, which are larger than the round‐off errors by orders of magnitude, have a superlinear relationship with both the simulation time‐step and the interparticle collision speed. This remains the case regardless of the simulation details including the chosen contact model, particle size distribution, particle density or stiffness. Hence, the total errors can usually be reduced by choosing a smaller time‐step. Increasing the polydispersity in a simulation by including smaller particles necessitates choosing a smaller time‐step to maintain simulation stability and reduces the truncation errors in most cases. The truncation errors are increased by the dissipation of energy by frictional sliding or by the inclusion of damping in the system. The number of contacts affects the accuracy, and one can deduce that because 2D simulations contain fewer interparticle contacts than the equivalent 3D simulations, they therefore have lower accrued simulation errors. Copyright © 2016 John Wiley & Sons, Ltd.     

A novel framework for analyzing the green value of food supply chain based on life cycle assessment

The environmental impact is one of the major pillars of concerns when addressing the sustainability of food supply chain. In life cycle assessment of food supply chain, a particular environmental impact category from farming to distribution is aggregated. These values are widely used in determining which supply chain is performing more environmentally sound on the basis of a particular impact category. However, when different categories of environmental impacts are represented in one matrix, different impact categories can exhibit increasing and decreasing trends simultaneously for the same product. Moreover, different impact categories have different units of measurement. All of these factors make it difficult to clearly prefer one supply chain to the other. Therefore, a quantifiable indicator is desirable for each individual product which can represent all impact categories for a single product through a single index and can be easily comparable during decision making. This paper presents a new framework to compute a single index based on Life cycle assessment using vector space theory. This index can be utilized to compare the environmental sustainability among various food supply chains. The index is named as green value of a supply chain. The use of this proposed green value is explained through three case studies with different goals, scopes, system boundaries, and functional units. It is also shown that how the order of green value varies by changing the functional unit of the same product. The contribution of green value is the better interpretation of Life cycle assessment result for the purpose of decision making and is easily understandable to customers, manufacturers, policy makers, and other stakeholders.     

Lipid-based nanocarrier for quercetin delivery: system characterization and molecular interactions studies

The flavonoid quercetin (QU) is a naturally occurring compound with several biological activities. However, the oral bioavailability of this compound is very low due to the high pre-systemic metabolism in the colon and liver and its low water solubility. In this context, the development of QU-loaded nanocarriers (NEs) is a promising approach to improve the drug oral bioavailability. This study investigates the variation of the concentration of 12-hydroxystearic acid–polyethylene glycol copolymer, lecithin and castor oil (CO) as to increase the amount of QU encapsulated while maintaining physicochemical characteristics described in previous studies. To better understand the ability to load and release the drug, we investigated the molecular interactions between QU and NE. Lipid-based NEs were prepared using CO as oily phase and PEG 660-stearate and lecithin as surfactants. Hot solvent diffusion and phase inversion temperature were methods employed to produce NEs. The QU-NEs were investigated for physicochemical characteristics and in vitro drug release. Molecular interactions between QU and the NEs were monitored through the complementary infrared (Fourier transform infrared) and NMR. The results revealed that it was possible to incorporate higher amounts of QU in a lipid-based NE with a reduced size (20?nm). The system developed allow a sustained release of QU probably due to the shell formed by the surfactants around the NE and the flavonoid ordering effect in the emulsion hydrophobic regions, which may reduce the system permeability.     

The effect of measuring error on the results of therapeutic trials in advanced cancer

In this study, 16 experienced oncologists each measured 12 simulated tumor masses employing their usual clinical methods. Unknown to the oncologists, two pairs of these tumors were identical in size. This permitted a total of 64 measurement comparisons of the same investigator measuring the same size mass and 1920 comparisons of different investigators measuring the same size mass. If a 50% reduction in the product of perpendicular diameters is accepted as a criterion, the objective response rate due to measuring error alone was 7.8% by the same investigator and 6.8% by different investigators. If a 25% reduction criterion is used, the respective "placebo" response rates were 19% and 25%. In the clinical setting it is recommended that the 50% reduction criterion be employed and that the investigator should anticipate an objective response rate of 5 to 10% due to human error in tumor measurement.     

The choices people make: the types of buddy icons people select for self-presentation online

People are adapting their self-presentation strategies to utilize both online and offline communication in their interactions with strangers, co-workers, family, and friends. One way people communicate online is through the use of instant messaging, which includes the use of graphical representations of people called buddy icons. This project presents the results of a survey of the buddy icons 93 participants were currently using in their instant messaging interactions. It examines the extent to which self-presentation theory (Goffman 1959) can explain the choices people are making about how to self-present elements of their identity online. The icons were categorized and users were asked why they choose them as well as when and whether they change them with different interaction partners. Results show that male users select different categories of buddy icons than females but that most users select buddy icons that are human like, low on photorealism, and consistent with their biological sex. Users also reported that they rarely change their icons and that they selected human buddy icons when they want to increase social presence.     

Effect of protein source and resistance training on body composition and sex hormones

Background  

Evidence suggests an inverse relationship between soy protein intake and serum concentrations of male sex hormones. Anecdotal evidence indicates that these alterations in serum sex hormones may attenuate changes in lean body mass following resistance training. However, little empirical data exists regarding the effects of soy and milk-based proteins on circulating androgens and exercise induced body composition changes.     

Ferrography: Its application to the study of human joint wear

Synovial fluid aspirates of 20 arthroplastic and 150 osteoarthritic joints were analyzed for evidence of wear particles. Ferrography, an industrial technique for the separation of particulate matter from samples of lubricating solutions, allows extraction of wear particles from synovial fluid. Bichromatic polarized microscopy and scanning electron microscopy permit identification and characterization of metallic, polyethylene and acrylic wear particles from arthroplastic joints as well as biological wear fragments of bone, cartilage, meniscus and synovium from osteoarthritic joints. With both techniques, the number and morphology of the wear particles within the synovial fluid specimens correlate with the rate and mechanism of wear as confirmed by examination of the joint implant or articular surfaces. Toxicity of the various types of wear particles was assessed by cytological examination of the fluid aspirate. Of significant interest is the identification of active phagocytosis of wear particles by synovial fluid white blood cells. This finding may implicate the particles as initiators of secondary inflammatory responses, as occurs in other arthritic diseases.Analysis of aspirated synovial fluid appears to be a useful method for studying the rates, mechanisms and biological responses to wear in both arthroplastic and degenerative joints. In surgical joint replacement, this technique holds much promise, not only as a test for wear and toxicity, but also as a means of assisting in the selection of materials and designs for superior articular implants. In osteoarthritic joints, this analysis provides a method for early diagnosis, serial assessment of therapy and prognostication concerning the future course of the disease. Possibly of most significance, in contrast to previous studies on intact articular surfaces, is the ability to study the principal site of degenerative changes, namely the wear particles. This ability may aid in the elucidation of the underlying cause of osteoarthritis.