Ideologies of computer scientists and technologists (Correctness beyond reason)

Ideologies of computer scientists and technologist

Probing variations in the fundamental constants with quasar absorption lines

Precision cosmology challenges many aspects of fundamental physics. In particular, quasar absorption lines test the assumed constancy of fundamental constants over cosmological time-scales and distances. Until recently, the most reliable technique was the alkali doublet (AD) method where the measured doublet separation probes variations in the fine-structure constant, $\alpha \equiv e^2/\hbar c$. However, the recently introduced many-multiplet (MM) method provides several advantages, including a demonstrated ≈10-fold precision gain. This thesis presents detailed MM analyses of 3 independent Keck/HIRES samples containing 128 absorption systems with $0.2 < z_{\rm abs} < 3.7$. We find $5.6\sigma$ statistical evidence for a smaller α in the absorption clouds: $\Delta\alpha/\alpha = (-0.574 \pm 0.102) \times 10^{-5}$. All three samples separately yield consistent, significant $\Delta\alpha/\alpha$. The data marginally prefer constant $d\alpha/dt$ rather than constant $\Delta\alpha/\alpha$. The two-point correlation function for α and the angular distribution of $\Delta\alpha/\alpha$ give no evidence for spatial variations. We also analyse 21 Keck/HIRES Si iv doublets, obtaining a 3-fold relative precision gain over previous AD studies: $\Delta\alpha/\alpha = (0.5 \pm 1.3) \times 10^{-5}$ for $2.0 < z_{\rm abs} < 3.1$. Our statistical evidence for varying α requires careful consideration of systematic errors. Modelling demonstrates that atmospheric dispersion is potentially important. However, the quasar spectra suggest a negligible effect on $\Delta\alpha/\alpha$. Cosmological variation in Mg isotopic abundances may affect $\Delta\alpha/\alpha$ at $z_{\rm abs} < 1.8$. Galactic observations and theory suggest diminished 25,26Mg abundances in the low metallicity quasar absorbers. Removing 25,26Mg isotopes yields more negative $\Delta\alpha/\alpha$ values. Overall, known systematic errors can not explain our results. We also constrain variations in $y = \alpha^2g_{\rm p}$, comparing H I 21-cm and millimetre-wave molecular absorption in 2 systems. Fitting both the H I and molecular lines yields the tightest, most reliable current constraints: $\Delta y/y = (-0.20 \pm 0.44) \times 10^{-5}$ and $\Delta y/y = (-0.16 \pm 0.54) \times 10^{-5}$ at $z_{\rm abs} = 0.2467$ and 0.6847 respectively. Possible line-of-sight velocity differences between the H I and molecular absorbing regions dominate these $1\sigma$ errors. A larger sample of mm/H I comparisons is required to reliably quantify this uncertainty and provide a potentially crucial check on the MM result

Social conditions of outstanding contributions to computer science : a prosopography of Turing Award laureates (1966-2016)

The Turing Award, commonly described as computer science's highest award and equivalent of the Nobel prize in that discipline, has now been awarded for half a century. In the following, we describe the social regularities that underlie and the conditions that embed these high achievements in computer science innovation. We find, contrary to a meritocratic ideal of one's only abilities determining success or recognition within sciences, that several characteristics of scientists, exogenous and non-exogenous alike to their scientific work and identities, are of overbearing or disproportionate importance in defining academic acknowledgement. We find in particular that nationality or birth place, gender and one's network have a big role in making Turing Award laureates. As do social origins, with a significant portion of Turing Award winners coming primarily from middle- and upper-class family backgrounds, especially households with significant cultural capital i.e. one or both parents hold an advanced degree or are engaged in an academic profession). Reviewing the data before us, we were also unable to ignore the non-participation of visible minorities and non-white computer scientists to the body of Turing Award recipients. In short, place of birth, nationality, gender, social background, "race" and networks play a role in making Turing Award laureates. This paper also explores the ways in which a social history or sociology of computer science and the wider technology sector may unfold in the future, by discussing theoretical implications, methods and sources

IDENTIFICATION AND QUANTIFICATION OF VARIABILITY MEASURES AFFECTING CODE REUSABILITY IN OPEN SOURCE ENVIRONMENT

Open source software (OSS) is one of the emerging areas in software engineering, and is gaining the interest of the software development community. OSS was started as a movement, and for many years software developers contributed to it as their hobby (non commercial purpose). Now, OSS components are being reused in CBSD (commercial purpose). However, recently, the use of OSS in SPL is envisioned recently by software engineering researchers, thus bringing it into a new arena. Being an emerging research area, it demands exploratory study to explore the dimensions of this phenomenon. Furthermore, there is a need to assess the reusability of OSS which is the focal point of these disciplines (CBSE, SPL, and OSS). In this research, a mixed method based approach is employed which is specifically 'partially mixed sequential dominant study'. It involves both qualitative (interviews) and quantitative phases (survey and experiment). During the qualitative phase seven respondents were involved, sample size of survey was 396, and three experiments were conducted. The main contribution of this study is results of exploration of the phenomenon 'reuse of OSS in reuse intensive software development'. The findings include 7 categories and 39 dimensions. One of the dimension factors affecting reusability was carried to the quantitative phase (survey and experiment). On basis of the findings, proposal for reusability attribute model was presented at class and package level. Variability is one of the newly identified attribute of reusability. A comprehensive theoretical analysis of variability implementation mechanisms is conducted to propose metrics for its assessment. The reusability attribute model is validated by statistical analysis of I 03 classes and 77 packages. An evolutionary reusability analysis of two open source software was conducted, where different versions of software are analyzed for their reusability. The results show a positive correlation between variability and reusability at package level and validate the other identified attributes. The results would be helpful to conduct further studies in this area

IDENTIFICATION AND QUANTIFICATION OF VARIABILITY MEASURES AFFECTING CODE REUSABILITY IN OPEN SOURCE ENVIRONMENT

Open source software (OSS) is one of the emerging areas in software engineering, and is gaining the interest of the software development community. OSS was started as a movement, and for many years software developers contributed to it as their hobby (non commercial purpose). Now, OSS components are being reused in CBSD (commercial purpose). However, recently, the use of OSS in SPL is envisioned recently by software engineering researchers, thus bringing it into a new arena. Being an emerging research area, it demands exploratory study to explore the dimensions of this phenomenon. Furthermore, there is a need to assess the reusability of OSS which is the focal point of these disciplines (CBSE, SPL, and OSS). In this research, a mixed method based approach is employed which is specifically 'partially mixed sequential dominant study'. It involves both qualitative (interviews) and quantitative phases (survey and experiment). During the qualitative phase seven respondents were involved, sample size of survey was 396, and three experiments were conducted. The main contribution of this study is results of exploration of the phenomenon 'reuse of OSS in reuse intensive software development'. The findings include 7 categories and 39 dimensions. One of the dimension factors affecting reusability was carried to the quantitative phase (survey and experiment). On basis of the findings, proposal for reusability attribute model was presented at class and package level. Variability is one of the newly identified attribute of reusability. A comprehensive theoretical analysis of variability implementation mechanisms is conducted to propose metrics for its assessment. The reusability attribute model is validated by statistical analysis of I 03 classes and 77 packages. An evolutionary reusability analysis of two open source software was conducted, where different versions of software are analyzed for their reusability. The results show a positive correlation between variability and reusability at package level and validate the other identified attributes. The results would be helpful to conduct further studies in this area