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Cash Flow Forecasting for Self-employed Workers: Fuzzy Inference Systems or Parametric Models?
No full textCash flow forecasting is an important task for any organization, but it becomes crucial for self-employed workers. In this paper, we model the cash flow of three real self-employed workers as a time series problem and compare the performance of conventional parametric methods against two types of fuzzy inference systems in terms of both prediction error and processing time. Our evaluation demonstrates that there is no winning model, but that each forecasting method’s performance depends on the characteristics of the cash flow data. However, experimental results suggest that parametric methods and Mamdani-type fuzzy inference systems outperform Takagi–Sugeno–Kang-type systems
The magnetic states in cobalt‑promoted MoS2 microspheres
No full textThe cobalt-promoted MoS2 microspheres have been synthesized by hydrothermal methods using sodium molybdate precursors. Scanning electron microscopy indicates that spherical shape morphology and cobalt atoms are detected at MoS2 edges corresponding to (101)-plane as revealed by Cs-corrected transmission electron microscopy. The magnetic states were measured by magnetization curves obtaining a 0.044 emu/g due to paramagnetic contribution. Furthermore, the electronic structure from the density of states for 2H-MoS2 with and without cobalt at the (101) edge plane possesses a magnetic property with a value of 0.16 μB attributed to broken symmetry
Enhanced syngas ( H2/CO) production by Co/CeO2 nanorods catalyst through dry reforming of methane
No full textThis study presents the synthesis and characterization of the Co supported on CeO2 nanorods (NR) catalyst to investigate catalytic performance towards efficient hydrogen production. The catalyst was characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Temperature-programmed reduction measurements showed that the Co/CeO2-NR active phase was reduced below 500°C. Adding Co to CeO2-NR enhances the basicity of the raw CeO2-NR and greatly improves the conversion to 70% for CO2 and 55% for CH4. In addition, density functional theory calculations using Halgren–Lipscomb indicate electron donation from Co to CeO2-NR promotes feasible breaking of C–H bonds
Effect of Rare Earth Elements Addition and Sintering Conditions on the Microstructure and Microhardness of Inconel 718
No full textA series of Inconel 718 alloys modified by additions of 0.1-0.3 of a mixture of rare earth elements Ce:La:Nd:Pr have been synthesized by powder metallurgy. These alloys were sintered by conventional and hot isostatic pressure methods and subject to standard aging treatment. The results showed that adding rare earth elements generates γ′ and γ″ precipitates with a minor size than those reported. Additionally, the presence of rare earth elements causes the formation of La-Ti-Al-O phases that act as reinforcing particles. The highest microhardness values were obtained in the samples with 0.3 wt.% of rare earth elements and sintered by hot isostatic pressure. These hardness values are attributed to the precipitation of the nanophases (γ′ and γ″), the high numeric density of dispersed oxides and carbides, and solid solution strengthening generated by rare earth elements addition and dissolution of elements in the Nb, Ti and Mo rich phases
El modelo del desarrollo de dimensiones que explican los obstáculos de las mujeres universitarias de la Universidad Autónoma de Ciudad Juárez en Juárez, Chihuahua, México, que dirigen una Micro y Pequeña empresa en Juárez
No full textPor razones especialmente socioeconómicas y culturales, las mujeres y en particular las latinoamericanas, están ingresando cada vez más, en el ámbito académico al tener la oportunidad de cursar sus estudios universitarios, además de que está incrementando su participación en el mundo productivo, aportando de manera significativa a la economía de sus países y a la de sus familias (Bonder, 2003), sin embargo, ello no implica una supresión de los obstáculos a los que se enfrentan para obtener poder y reconocimiento (Ortiz y Olaz, 2014).
Con el propósito de comprender dicho fenómeno, es que el presente capítulo ofrece
un modelo de desarrollo de dimensiones que explica los obstáculos de las mujeres universitarias que dirigen una micro y pequeña empresa, a partir de un estudio que se llevó a cabo en la Universidad Autónoma de Ciudad Juárez, ubicada en Juárez, Chihuahua, México
La importancia de la inmigración en el mercado laboral americano
No full textLa inmigración ha sido un tema controvertido en los Estados Unidos por décadas. Los críticos de la migración han querido establecer, erróneamente, que los trabajadores inmigrantes impactan negativamente a los trabajadores nativos en los Estados Unidos. Argumentan que los inmigrantes desplazan a estos trabajadores y deprimen sus salarios. Además, la retórica del expresidente Donald Trump, al llamar a los trabajadores indocumentados criminales, asesinos y violadores, crea un ambiente hostil e impide entender, primero, las causas por las que ellos emigran de sus países a los Estados Unidos y, segundo, la importancia que los inmigrantes, documentados e indocumentados, tienen para la economía de los Estados Unidos
The three-dimensional structure of DapE from Enterococcus faecium reveals new insights into DapE/ArgE subfamily ligand specificity
No full textDapE is a Zn2+-metallohydrolase recognized as a drug target for bacterial control. It is a homodimer that requires the exchange of interface strands by an induced fit essential for catalysis. Identifying novel anti-DapE agents requires greater structural details. Most of the characterized DapEs are from the Gram-negative group. Here, two high-resolution DapE crystal structures from Enterococcus faecium are presented for the first time with novel aspects. A loosened enzyme intermediate between the open and closed conformations is observed. Substrates may bind to loose state, subsequently it closes, where hydrolysis occurs, and finally, the change to the open state leads to the release of the products. Mutation of His352 suggests a role, along with His194, in the oxyanion stabilization in the mono-metalated Zn2+ isoform, while in the di-metalated isoform, the metal center 2 complements it function. An aromatic-π box potentially involved in the interaction of DapE with other proteins, and a peptide flip could determine the specificity in the Gram-positive ArgE/DapE group. Finally, details of two extra-catalytic cavities whose geometry changes depending on the conformational state of the enzyme are presented. These cavities could be a target for developing non-competitive agents that trap the enzyme in an inactive state
Influence of Mischmetal Rare Earth Elements Additions on the Microstructural Properties of HIP and Conventional Sintering Heat Treated Inconel 718
No full textInconel 718 superalloy is employed due to its high oxidation resistance and excellent mechanical performance at relative high work temperatures. Their most important applications are in aeronautics, aerospace engines, petrochemical industries as well as nuclear reactors
El Proceso DMAIC: Herramientas de Calidad en el Desarrollo de Proyectos de Mejora de la Calidad
No full texthttps://revistas.unicordoba.edu.co/index.php/rii/article/view/377
Aiding decision makers in articulating a preference closeness model through compensatory fuzzy logic for many-objective optimization problems
No full textOne of the main challenges in applying preference-based approaches to many-objective optimization problems is that decision makers (DMs) initially have only a vague notion of the solution they want and can obtain. In this paper, we propose an interactive approach that aids DMs in articulating a preference model in a progressive way. The quality of a solution is determined in terms of its “preference closeness” to an aspiration point, which is a subjective concept that can be outlined by the DM. Our proposal is based on compensatory fuzzy logic, which allows for the construction of predicates that are expressed in language that is close to natural. One main advantage is that the model can be optimized via metaheuristics, and we utilize an ant colony optimization algorithm for this. Our model complies with the principles of hybrid augmented intelligence, not only because the algorithm is enriched with knowledge from the DM, but also because the DM also learns the concept of “preference closeness” throughout the process. The proposed model is validated on benchmarks with five and 10 objective functions, and is compared with two state-of-the-art algorithms. Our approach allows for better convergence to the best compromise solutions. The advantages of our approach are supported by statistical tests of the results