ShOpt.jl: A Julia Package for Empirical Point Spread Function Characterization of JWST NIRCam Data

As astronomical data grows in volume and complexity, the scalability of analysis software becomes increasingly important. At the same time, astrophysics analysis software relies heavily on open-source contributions, so languages and tools that prioritize both performance and readability are especially valuable. Julia, with its just-in-time compiler and high level syntax, offers a compelling alternative to traditional languages like Python or C. In this paper, we outline ShOpt.jl, a new software package for point spread function (PSF) characterization written in Julia. ShOpt.jl features a number of performance optimizations, such as multithreading, the use of preconditioners, and the implementation of the memory-limited Broyden-Fletcher-Goldfarb-Shanno algorithm, as well as the flexibility to choose between principal component analysis, an autoencoder, and analytic profiles for PSF characterization. As observatories like the James Webb Space Telescope bring astrophysics into a new era of wide-field, high-resolution imaging, the challenges of PSF modeling become more pronounced. Tools like ShOpt.jl provide the community with a scalable, efficient, and accurate solution to these challenges, while also demonstrating the potential of Julia as a language that meets the demands of modern astrophysical research.Comment: 10 pages, 3 figures; submitted to the Journal of Open Source Softwar

3D numerical analysis of flow characteristics in an open – channel bend

[ES] El presente trabajo muestra un análisis numérico 3D del comportamiento del flujo de agua en un canal curvo influenciado por la presencia de un vertedero y una compuerta. La simulación numérica se realizó utilizando el software de Dinámica de Fluidos Computacional (CFD) basado en el método de volúmenes finitos (FVM) – OpenFOAM. En el modelo numérico la turbulencia se trata con la metodología RANS (k–ε, k–ω, y RNG k–ε) y se usa el método VOF (Volume of Fluid) para la captura de la superficie libre del agua. Los resultados numéricos obtenidos se evalúan al compararlos con los valores experimentales de calado en diferentes puntos dentro del dominio. Los valores de calado se midieron haciendo uso de sensores de nivel de agua y limnímetros. De esta manera, los resultados numéricos tridimensionales obtenidos son utilizados para analizar las líneas de corriente, las componentes de velocidades y los flujos secundarios.[EN] In this paper, three-dimensional numerical analysis of flow field patterns in an open channel bend influenced by a weir and a sluice gate is presented. The simulation was performed using the open source computational fluid dynamics (CFD) solver based on finite volume method (FVM) – OpenFOAM. Turbulence is treated using Reynolds-Averaged Navier Stokes equations (RANS) approach (i.e., k–ε, k–ω, y k–ε(RNG)), and the volume of fluid (VOF) method is used to simulate the air-water interface. The numerical results are assessed against experimental data (water depth) at different points within the domain. Water depths were measured by means of water level sensors and limnimeters. Therefore, the three-dimensional numerical results obtained are used to analyze streamlines, components of velocities, and secondary flows.Este trabajo fue posible gracias al financiamiento de la Secretaria de Educación Superior, Ciencia, Tecnología e Innovación (SENESCYT) del gobierno de la República del Ecuador a través de la beca doctoral del primer autor. Asimismo, los autores desean expresar su gratitud al Instituto de Investigación FLUMEN por facilitar sus instalaciones de laboratorio.Sánchez-Cordero, E.; Gómez, M.; Bladé, E. (2020). Análisis numérico 3D de las características del flujo en un canal curvo. Ingeniería del agua. 24(3):157-168. https://doi.org/10.4995/ia.2020.12276OJS157168243Celik, I., Ghia, U., Roache, P., Freitas, C. 2008. Procedure for Estimation and Reporting of Uncertainty Due to Discretization in CFD Applications. Journal of Fluids Engineering, 130(7), 1-4. https://doi.org/10.1115/1.2960953Gholami, A., Akbar Akhtari, A., Minatour, Y., Bonakdari, H., Javadi, A.A. 2014. Experimental and Numerical Study on Velocity Fields and Water Surface Profile in a Strongly-Curved 90° Open Channel Bend. Engineering Applications of Computational Fluid Mechanics, 8(3), 447-461. https://doi.org/10.1080/19942060.2014.11015528Gómez M., Martínez-Gomariz E. 2016. 1D, 2D, and 3D Modeling of a PAC-UPC Laboratory Canal Bend. In: Gourbesville P., Cunge J., Caignaert G. (eds) Advances in Hydroinformatics. Springer Water. Springer, Singapore. https://doi.org/10.1007/978-981-287-615-7_29Ippen, A.T., Drinker, P.A. 1962. Boundary Shear Stresses in Curved Trapezoidal Channels. Journal of the Hydraulics Division, 88(5), 143-180.Kalkwijk, J.P.T., de Vriend, H.J. 1980. Computational of the flow in shallow river bends. Journal of Hydraulic Research, 18(4), 327-342. https://doi.org/10.1080/00221688009499539Launder, B.E., Spalding, D.B. 1974. The numerical computation of turbulent flows. Computer Methods in Applied Mechanics and Engineering, 3(2), 269-289. https://doi.org/10.1016/0045-7825(74)90029-2MacCormack, R.W., Paullay, A.J. 1972. Computational Efficiency Achieved by Time Splitting of Finite Difference Operators. American Institute of Aeronautics and Astronautics, AIAA paper 72-154. https://doi.org/10.2514/6.1972-154MacDonald, P.W. 1971. The Computation of Transonic Flow Through Two- Dimensional Gas Turbine Cascades. American Society of Mechanical Engineers, (Paper 71-GT-89). https://doi.org/10.1115/71-GT-89Naji Abhari, M., Ghodsian, M., Vaghefi, M., Panahpur, N. 2010. Experimental and numerical simulation of flow in a 90° bend. Flow Measurement and Instrumentation, 21(3), 292-298. https://doi.org/10.1016/j.flowmeasinst.2010.03.002Ramamurthy, A.S., Han, S.S., Biron, P.M. 2013. Three-Dimensional Simulation Parameters for 90° Open Channel Bend Flows. Journal of Computing in Civil Engineering, 27(3), 282-291. https://doi.org/10.1061/(ASCE)CP.1943-5487.0000209Rozovskiĭ, I. 1957. Flow of water in bends of open channels. Academy of Sciences of the Ukrainian SSR, Kiev, USSR (translated by the Israel Program for Scientific Translations, Jerusalem, 1961), Academy of Sciences of the Ukrainian SSR; Israel Program for Scientific Translations]; Kiev;[Washington D.C. available from the Office of Technical Services U.S. Dept. of Commerce].Wilcox, D.C. 1994. Turbulence Modeling for CFD. (C.D. La Canada and Industries, eds.), DCW Industries, La Canada, California (USA).Yakhot, V., Orszag, S.A. 1986. Renormalization group analysis of turbulence. I. Basic theory. Journal of Scientific Computing, Kluwer Academic/Plenum Publishers, 1(1), 3-51. https://doi.org/10.1007/BF0106145

Research Agenda for Studying Open Source II: View Through the Lens of Referent Discipline Theories

In a companion paper [Niederman et al., 2006] we presented a multi-level research agenda for studying information systems using open source software. This paper examines open source in terms of MIS and referent discipline theories that are the base needed for rigorous study of the research agenda

Myths and Realities about Online Forums in Open Source Software Development: An Empirical Study

The use of free and open source software (OSS) is gaining momentum due to the ever increasing availability and use of the Internet. Organizations are also now adopting open source software, despite some reservations, in particular regarding the provision and availability of support. Some of the biggest concerns about free and open source software are post release software defects and their rectification, management of dynamic requirements and support to the users. A common belief is that there is no appropriate support available for this class of software. A contradictory argument is that due to the active involvement of Internet users in online forums, there is in fact a large resource available that communicates and manages the provision of support. The research model of this empirical investigation examines the evidence available to assess whether this commonly held belief is based on facts given the current developments in OSS or simply a myth, which has developed around OSS development. We analyzed a dataset consisting of 1880 open source software projects covering a broad range of categories in this investigation. The results show that online forums play a significant role in managing software defects, implementation of new requirements and providing support to the users in open source software and have become a major source of assistance in maintenance of the open source projects

A Research Agenda for Studying Open Source I: A Multi-Level Framework

This paper presents a research agenda for studying information systems using open source software A multi-level research model is developed at five discrete levels of analysis: (1) the artifact; (2) the individual; (3) the team, project, and community; (4) the organization; and (5) society. Each level is discussed in terms of key issues within the level. Examples are based on prior research. In a companion paper, [Niederman, et al 2006], we view the agenda through the lens of referent discipline theories

A Study on the Open Source Digital Library Software's: Special Reference to DSpace, EPrints and Greenstone

The richness in knowledge has changed access methods for all stake holders in retrieving key knowledge and relevant information. This paper presents a study of three open source digital library management software used to assimilate and disseminate information to world audience. The methodology followed involves online survey and study of related software documentation and associated technical manuals.Comment: 9 Pages, 3 Figures, 1 Table, "Published with International Journal of Computer Applications (IJCA)