The Making of Cloud Applications An Empirical Study on Software Development for the Cloud

Cloud computing is gaining more and more traction as a deployment and provisioning model for software. While a large body of research already covers how to optimally operate a cloud system, we still lack insights into how professional software engineers actually use clouds, and how the cloud impacts development practices. This paper reports on the first systematic study on how software developers build applications in the cloud. We conducted a mixed-method study, consisting of qualitative interviews of 25 professional developers and a quantitative survey with 294 responses. Our results show that adopting the cloud has a profound impact throughout the software development process, as well as on how developers utilize tools and data in their daily work. Among other things, we found that (1) developers need better means to anticipate runtime problems and rigorously define metrics for improved fault localization and (2) the cloud offers an abundance of operational data, however, developers still often rely on their experience and intuition rather than utilizing metrics. From our findings, we extracted a set of guidelines for cloud development and identified challenges for researchers and tool vendors

Investigation of prediction methods for the loads and stresses of Apollo type spacecraft parachutes. Volume 1: Loads

An analysis was conducted with the objective of upgrading and improving the loads, stress, and performance prediction methods for Apollo spacecraft parachutes. The subjects considered were: (1) methods for a new theoretical approach to the parachute opening process, (2) new experimental-analytical techniques to improve the measurement of pressures, stresses, and strains in inflight parachutes, and (3) a numerical method for analyzing the dynamical behavior of rapidly loaded pilot chute risers

BKT-like transition in the Potts model on an inhomogeneous annealed network

We solve the ferromagnetic q-state Potts model on an inhomogeneous annealed network which mimics a random recursive graph. We find that this system has the inverted Berezinskii--Kosterlitz--Thouless (BKT) phase transition for any $q \geq 1$, including the values $q \geq 3$, where the Potts model normally shows a first order phase transition. We obtain the temperature dependences of the order parameter, specific heat, and susceptibility demonstrating features typical for the BKT transition. We show that in the entire normal phase, both the distribution of a linear response to an applied local field and the distribution of spin-spin correlations have a critical, i.e. power-law, form.Comment: 7 pages, 3 figure

Using of Naproxen drug for novel synthesis of 4-thiazolidinone derivatives and application of these drugs as no steroidal anti-inflammatory drug (NSAIDs) and as anti-epileptic agent

Non-steroidal anti-inflammatory drugs (NSAIDs) are now one of the most frequent drugs used in treatment of pain, inflammation and fever. In this study the aim is the synthesis of derivatives of 4-Tiazolidinon from naproxen with the possible anti-pain effects, and the main purpose of providing these derivatives is to achieve a compound with more anti-pain power and less side effects in comparison with applied drugs in clinics. Synthesis of these derivatives is done on chloride in presence of a group of new liquids like recyclable ionic liquids choline chloride, which the main advantages of these ionic liquids are the cheapness, availability, being non-toxic, and easy recyclability. This reaction was done in four stages. All the structures were verified by using data of spectrum testing, 1H-NMR, FT-IR

Future Renewable Energy Communities Based Flexible Power Systems

This paper presents a new holistic approach that combines solutions for the future power systems. It describes clearly how solar energy is definitely the best outlet for a clean and sustainable planet, either due to their use in both vertical (V) or horizontal (H) forms such as: hydroelectric V&H, wind V&H, thermo-oceanic V&H, water movement sea V&H (tides and waves), solar thermoelectric, PV, and surface geothermal energy. New points of view and simple formulas are suggested to calculate the best characteristic intensity, storage means and frequency for specific places and how to manage the most well-known renewable sources of energy. Future renewables-based power system requires a huge amount of flexibility from different type and size of controllable energy resources. These flexible energy resources can be used in an aggregated manner to provide different ancillary services for the distribution and transmission network. In addition, flexible energy resources and renewable generation can be utilized in different kinds of energy communities and smart cities to benefit all stakeholders and society at the same time with future-proof market structures, new business models and management schemes enabling increased utilization of flexible energy resources. Many of the flexible energy resources and renewable-based generation units are also inverter-interfaced and therefore the authors present future power converter systems for energy sources as well as the latest age of multilevel converters.© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Compact tri-band Wilkinson power divider based on metamaterial structure for Bluetooth, WiMAX, and WLAN applications

A novel Wilkinson power divider is presented in this paper for triple band operation. It comprises a П-shaped transmission-line coupled to a rectangular split ring resonator metamaterial structure. The μ-negative feature of the rectangular split ring resonator metamaterial structure is investigated by retrieving its constitutive parameters from the S-parameter response. To demonstrate the versatility of the proposed Wilkinson power divider it was designed to cover Bluetooth (2.4 GHz), WiMAX (3.5 GHz), and WLAN (5.2 GHz). The tri-band Wilkinson power divider was fabricated and its performance measured to verify the design. Good agreement between the measured and simulated data is obtained. Measured results show that the tri-band Wilkinson power divider has fractional bandwidth of 3.86%, 5.82%, and 3.89% at 2.4, 3.5, and 5.2 GHz, respectively. In addition, the rectangular split ring resonator metamaterial Wilkinson power divider has a small physical footprint (14 mm ×17.9 mm or 0.15λg×0.19λg), which is 60% smaller than conventional designs

Evaluating the Effects of Fertilizers on Bioavailable Metallic Pollution of soils, Case study of Sistan farms,

ABSTRACT: Present study determines not only the total amounts of metals (Cr, Cu and Pb) in superficial agricultural soil of Sistan area in Eastern Iran, but also the chemical partitioning of these elements in seven statistically selected cases. The analysis was run for local soil, soil treated by non-contaminated organic, compost and chemical fertilizers as well as soil treated by metal-contaminated fertilizers. The sampling campaign was done in Zabol University research farm in 2009. The grab samples were taken from seven different cases, the chemical partitioning analysis was performed and metallic concentrations were detected using FAAS. It may be concluded that the bioaccessibility of metals Cu and Cr would be increased in case of imposed contamination where the soil is treated with all three kinds of fertilizers. Although a relatively similar distribution pattern is seen between anthropogenic and geopogenic portions of bulk concentration in all three kinds of fertilizers, chemical fertilizer seems to manifest a more risky condition. According to the results achieved by cluster analysis, a close correlation exists between Cu and Cr behavior which may be attributed to the geological texture of the study area. In accordance with the results gained by partitioning analysis, I POLL index values also show contaminated chemical fertilizer as the most risky case for all three metals in comparison with others

Proton-deuteron radiative capture cross sections at intermediate energies

Differential cross sections of the reaction $p(d,^3{\rm He})\gamma$ have been measured at deuteron laboratory energies of 110, 133 and 180 MeV. The data were obtained with a coincidence setup measuring both the outgoing $^3$He and the photon. The data are compared with modern calculations including all possible meson-exchange currents and two- and three- nucleon forces in the potential. The data clearly show a preference for one of the models, although the shape of the angular distribution cannot be reproduced by any of the presented models.Comment: 6 pages, 6 figures, accepted for publication in EPJ