Pengelompokan Tim Pengembang Berdasarkan Kriteria Perilaku Manusia dalam Kolaborasi Pengembangan Perangkat Lunak

Teknologi informasi merupakan bidang yang berkembang cukup pesat di akhir dekade ini. Hal tersebut ditandai dengan meningkatnya kebutuhan akan teknologi informasi. Salah satu bagian dari proyek teknologi informasi yang berkembang cukup pesat adalah proyek pengembangan perangkat lunak yang mempunyai ketidakpastian tinggi dengan tingkat kesuksesan yang rendah. Kualitas dan kecepatan proyek perangkat lunak sangat tergantung pada faktor sumber daya manusia. Tujuan penelitian ini adalah untuk mengembangkan sebuah strategi dan kriteria dengan mengelompokkan perilaku tim pengembang sehingga metode kolaborasi yang akan dilakukan dapat disesuaikan dengan susunan tim yang terlibat dalam pengembangan perangkat lunak. Pengelompokan perilaku programmer dalam kolaborasi tim pengembang perangkat lunak dilakukan dengan menggunakan analisis kluster dengan melihat lima variabel, yaitu usia, gender, interaksi dan komunikasi, kondisi psikologis, dan pemrosesan informasi. Pengujian diambil dari 35 programmer yang berasal dari industri perangkat lunak yang terdapat di Bandung dengan menyebar kuisioner pada tim pengembang secara online maupun offline. Hasil pengolahan data dengan software SPSS menunjukkan bahwa terdapat tiga kluster perilaku programmer dalam kolaborasi tim pengembangan perangkat lunak. Dengan diketahuinya pengelompokan perilaku programmer diharapkan tim pengembang yang dibentuk dapat menghasilkan perangkat lunak dengan kualitas yang lebih baik

Structure preserving schemes for mean-field equations of collective behavior

In this paper we consider the development of numerical schemes for mean-field equations describing the collective behavior of a large group of interacting agents. The schemes are based on a generalization of the classical Chang-Cooper approach and are capable to preserve the main structural properties of the systems, namely nonnegativity of the solution, physical conservation laws, entropy dissipation and stationary solutions. In particular, the methods here derived are second order accurate in transient regimes whereas they can reach arbitrary accuracy asymptotically for large times. Several examples are reported to show the generality of the approach.Comment: Proceedings of the XVI International Conference on Hyperbolic Problem

Uncertainty quantification for kinetic models in socio-economic and life sciences

Kinetic equations play a major rule in modeling large systems of interacting particles. Recently the legacy of classical kinetic theory found novel applications in socio-economic and life sciences, where processes characterized by large groups of agents exhibit spontaneous emergence of social structures. Well-known examples are the formation of clusters in opinion dynamics, the appearance of inequalities in wealth distributions, flocking and milling behaviors in swarming models, synchronization phenomena in biological systems and lane formation in pedestrian traffic. The construction of kinetic models describing the above processes, however, has to face the difficulty of the lack of fundamental principles since physical forces are replaced by empirical social forces. These empirical forces are typically constructed with the aim to reproduce qualitatively the observed system behaviors, like the emergence of social structures, and are at best known in terms of statistical information of the modeling parameters. For this reason the presence of random inputs characterizing the parameters uncertainty should be considered as an essential feature in the modeling process. In this survey we introduce several examples of such kinetic models, that are mathematically described by nonlinear Vlasov and Fokker--Planck equations, and present different numerical approaches for uncertainty quantification which preserve the main features of the kinetic solution.Comment: To appear in "Uncertainty Quantification for Hyperbolic and Kinetic Equations

Physical structure of the envelopes of intermediate-mass protostars

Context: Intermediate mass protostars provide a bridge between low- and high-mass protostars. Furthermore, they are an important component of the UV interstellar radiation field. Despite their relevance, little is known about their formation process. Aims: We present a systematic study of the physical structure of five intermediate mass, candidate Class 0 protostars. Our two goals are to shed light on the first phase of intermediate mass star formation and to compare these protostars with low- and high-mass sources. Methods: We derived the dust and gas temperature and density profiles of the sample. We analysed all existing continuum data on each source and modelled the resulting SED with the 1D radiative transfer code DUSTY. The gas temperature was then predicted by means of a modified version of the code CHT96. Results: We found that the density profiles of five out of six studied intermediate mass envelopes are consistent with the predictions of the "inside-out" collapse theory.We compared several physical parameters, like the power law index of the density profile, the size, the mass, the average density, the density at 1000 AU and the density at 10 K of the envelopes of low-, intermediate, and high-mass protostars. When considering these various physical parameters, the transition between the three groups appears smooth, suggesting that the formation processes and triggers do not substantially differ

A low-mass protostar’s disk-envelope interface: disk-shadowing evidence from ALMA DCO⁺ observations of VLA1623

Context. Historically, due to instrumental limitations and a lack of disk detections, the structure of the transition from the envelope to the rotationally supported disk has been poorly studied. This is now possible with ALMA through observations of CO isotopologues and tracers of freezeout. Class 0 sources are ideal for such studies given their almost intact envelope and young disk. Aims. The structure of the disk-envelope interface of the prototypical Class 0 source, VLA1623A, which has a confirmed Keplerian disk, is constrained through modeling and analysis of ALMA observations of DCO+ (3−2) and C18O (2−1) rotational lines. Methods. The physical structure of VLA1623 is obtained from the large-scale spectral energy distribution (SED) and continuum radiative transfer. An analytic model using a simple network coupled with radial density and temperature profiles is used as input for a 2D line radiative transfer calculation for comparison with the ALMA Cycle 0 12-m array and Cycle 2 ACA observations of VLA1623. Results. The DCO+ emission shows a clumpy structure bordering VLA1623A’s Keplerian disk. This suggests a cold ring-like structure at the disk-envelope interface. The radial position of the observed DCO+ peak is reproduced in our model only if the region’s temperature is between 11 K and 16 K, lower than expected from models constrained by continuum data and source SED. Altering the density profile has little effect on the DCO+ peak position, but increased density is needed to reproduce the observed C18O tracing the disk. Conclusions. The observed DCO+ (3−2) emission around VLA1623A is the product of shadowing of the envelope by the disk observed in C18O. Disk-shadowing causes a drop in the gas temperature outside of the disk on >200 AU scales, encouraging the production of deuterated molecules. This indicates that the physical structure of the disk-envelope interface differs from the rest of the envelope, highlighting the drastic impact that the disk has on the envelope and temperature structure. The results presented here show that DCO+ is an excellent cold temperature tracer

Boltzmann and Fokker-Planck equations modelling the Elo rating system with learning effects

In this paper we propose and study a new kinetic rating model for a large number of players, which is motivated by the well-known Elo rating system. Each player is characterised by an intrinsic strength and a rating, which are both updated after each game. We state and analyse the respective Boltzmann type equation and derive the corresponding nonlinear, nonlocal Fokker-Planck equation. We investigate the existence of solutions to the Fokker-Planck equation and discuss their behaviour in the long time limit. Furthermore, we illustrate the dynamics of the Boltzmann and Fokker-Planck equation with various numerical experiments

Design optimization and dynamic analysis of a tensegrity-based footbridge

Tensegrity structures are spatial structural systems composed of struts and cables with pin-jointed connections. Their stability is provided by the self-stress state in tensioned and compressed members. Although much progress has been made in advancing research into the tensegrity concept, a rapid survey of current activities in engineering practice shows that much of its potential has yet to be accomplished. A design optimization study for a tensegrity-based footbridge is presented in order to further advance the tensegrity concept in modern structural engineering. In the absence of specific design guidelines, design requirements for a tensegrity footbridge are stated. A genetic algorithm based optimization scheme is used to find a cost-effective design solution. The dynamic performance of the tensegrity footbridge is studied through parametric studies. Design results illustrate that the proposed tensegrity-based footbridge meets typical static and dynamic design criteria

Sphingomyelin in Human Breast Milk might be Essential for the Hippocampus Maturation

BACKGROUND: It has been established that sphingomyelin present human breast milk is useful for the brain maturation and cognitive development. At 10 days of breastfeeding the sphingomyelin content is double that present in cow's milk and its content is independent of the maternal diet. The aim of the study was to analyze the content of sphingomyelin in breast milk at 3 months of breastfeeding and to consider the effect of this molecule on synaptic function and nerve conduction through the probable expansion of myelinated axons. METHODS: Therefore, to begin to define and assess this, we performed sphingolipidomic analysis in human breast milk. Then, we cultured embryonic hippocampal cells (HN9.10) in the presence of sphingomyelin at a concentration from 0.6% to 31% of human milk, estimated by considering its bioavailability and its passage into the interstitial fluid. To highlight the effect of sphingomyelin in the cells, cell viability and morphology were evaluated. Analyses of neutral sphingomyelinase gene and protein expression was performed. The entry of sphingomyelin into the cell was studied in immunofluorescence; the expression of heavy neurofilament (NF200) was tested with immunocytochemical technique. RESULTS: We demonstrated that sphingomyelin is able to enter cell nucleus and overexpress the sphingomyelin phosphodiesterase 4 (SMPD4) gene encoding for neutral sphingomyelinase (nSMase), an enzyme useful for its own metabolism. Later, cells displayed changes of the soma and the appearance of neurites supported by NF200 overexpression. CONCLUSIONS: We speculated that the sphingomyelin present in human breast milk is useful in part to regulate nuclear activity and in part to form myelin sheet to facilitate nerve cell maturation. As brain development occurs at 0-3 years, these data open a new avenue of potential intervention to integrate the infant formulas with SM to obtain a product similar to the maternal milk

Gas phase Elemental abundances in Molecular cloudS (GEMS) : III. Unlocking the CS chemistry: the CS plus O reaction

Context. Carbon monosulphide (CS) is among the most abundant gas-phase S-bearing molecules in cold dark molecular clouds. It is easily observable with several transitions in the millimeter wavelength range, and has been widely used as a tracer of the gas density in the interstellar medium in our Galaxy and external galaxies. However, chemical models fail to account for the observed CS abundances when assuming the cosmic value for the elemental abundance of sulfur. Aims. The CS+O -> CO + S reaction has been proposed as a relevant CS destruction mechanism at low temperatures, and could explain the discrepancy between models and observations. Its reaction rate has been experimentally measured at temperatures of 150-400 K, but the extrapolation to lower temperatures is doubtful. Our goal is to calculate the CS+O reaction rate at temperatures Methods. We performed ab initio calculations to obtain the three lowest potential energy surfaces (PES) of the CS+O system. These PESs are used to study the reaction dynamics, using several methods (classical, quantum, and semiclassical) to eventually calculate the CS + O thermal reaction rates. In order to check the accuracy of our calculations, we compare the results of our theoretical calculations for T similar to 150-400 K with those obtained in the laboratory. Results. Our detailed theoretical study on the CS+O reaction, which is in agreement with the experimental data obtained at 150-400 K, demonstrates the reliability of our approach. After a careful analysis at lower temperatures, we find that the rate constant at 10 K is negligible, below 10(-15) cm(3) s(-1), which is consistent with the extrapolation of experimental data using the Arrhenius expression. Conclusions. We use the updated chemical network to model the sulfur chemistry in Taurus Molecular Cloud 1 (TMC 1) based on molecular abundances determined from Gas phase Elemental abundances in Molecular CloudS (GEMS) project observations. In our model, we take into account the expected decrease of the cosmic ray ionization rate, zeta(H2), along the cloud. The abundance of CS is still overestimated when assuming the cosmic value for the sulfur abundance.Peer reviewe