Mapping General System Characteristics to Non- Functional Requirements

The Function point analysis (FPA) method is the preferred scheme of estimation for project managers to determine the size, effort, schedule, resource loading and other such parameters. The FPA method by International Function Point Users Group (IFPUG) has captured the critical implementation features of an application through fourteen general system characteristics. However, Non- functional requirements (NFRs) such as functionality, reliability, efficiency, usability, maintainability, portability, etc. have not been included in the FPA estimation method. This paper discusses some of the NFRs and tries to determine a degree of influence for each of them. An attempt to factor the NFRs into estimation has been made. This approach needs to be validated with data collection and analysis.Comment: 5 page

Psychological Costs of Migration: Home Country Natural Disasters and Mental Health

The psychological toll of leaving one's familiar environment is a dominant explanation for why some people do not migrate despite relatively high wage differentials and low monetary costs of moving. Yet there is little direct empirical evidence on the existence and the characteristics of psychic costs. Using linked administrative and survey data (the 45 and Up Study) from Australia, a country where one in four residents was born overseas, we show that migrant mental health is significantly affected by home country natural disasters. In the three months following a disaster, mental health related drug use and visits to mental health specialists increase by 5% and 33%, respectively. The effects persist for up to 12 months after the initial shock and increase with distance to the home country. In contrast, we do not find any effects of home country disasters on the physical health conditions of migrants. Given that individuals in our sample have lived in their destination country for an average of 40 years, our estimates suggest strong persistence in these costs

Quantifying the non-Gaussianity in the EoR 21-cm signal through bispectrum

The epoch of reionization (EoR) 21-cm signal is expected to be highly non-Gaussian in nature and this non-Gaussianity is also expected to evolve with the progressing state of reionization. Therefore the signal will be correlated between different Fourier modes ($k$). The power spectrum will not be able capture this correlation in the signal. We use a higher-order estimator -- the bispectrum -- to quantify this evolving non-Gaussianity. We study the bispectrum using an ensemble of simulated 21-cm signal and with a large variety of $k$ triangles. We observe two competing sources driving the non-Gaussianity in the signal: fluctuations in the neutral fraction ($x_{\rm HI}$) field and fluctuations in the matter density field. We find that the non-Gaussian contribution from these two sources vary, depending on the stage of reionization and on which $k$ modes are being studied. We show that the sign of the bispectrum works as a unique marker to identify which among these two components is driving the non-Gaussianity. We propose that the sign change in the bispectrum, when plotted as a function of triangle configuration $\cos{\theta}$ and at a certain stage of the EoR can be used as a confirmative test for the detection of the 21-cm signal. We also propose a new consolidated way to visualize the signal evolution (with evolving $\overline{x}_{\rm HI}$ or redshift), through the trajectories of the signal in a power spectrum and equilateral bispectrum i.e. $P(k)-B(k, k, k)$ space.Comment: 18 pages, 11 figures. Accepted for publication in MNRAS. Replaced to match the accepted versio

Mental health stigma

Comparing self-reports to administrative records, we find that survey respondents are significantly more likely to under-report mental illnesses compared to other health conditions. This behavior is consistent with the existence of stigma of mental illnesses. We show that stigma can play a role in determining health-seeking behavior

The CMBR ISW and HI 21-cm Cross-correlation Angular Power Spectrum

The late-time growth of large scale structures (LSS) is imprinted in the CMBR anisotropy through the Integrated Sachs Wolfe (ISW) effect. This is perceived to be a very important observational probe of dark energy. Future observations of redshifted 21-cm radiation from the cosmological neutral hydrogen (HI) distribution hold the potential of probing the LSS over a large redshift range. We have investigated the possibility of detecting the ISW through cross-correlations between the CMBR anisotropies and redshifted 21-cm observations. Assuming that the HI traces the dark matter, we find that the ISW-HI cross-correlation angular power spectrum at an angular multipole l is proportional to the dark matter power spectrum evaluated at the comoving wave number l/r, where r is the comoving distance to the redshift from which the HI signal originated. The amplitude of the cross-correlation signal depends on parameters related to the HI distribution and the growth of cosmological perturbations. However the cross-correlation is extremely weak as compared to the CMBR anisotropies and the predicted HI signal. As a consequence the cross-correlation signal is smaller than the cosmic variance, and a statistically significant detection is not very likely.Comment: 13 pages, 4 eps figures, submitte

Study of the de Almeida-Thouless (AT) line in the one-dimensional diluted power-law XY spin glass

We study the AT line in the one-dimensional power-law diluted XY spin glass model, in which the probability that two spins separated by a distance $r$ interact with each other, decays as $1/r^{2\sigma}$. We develop a heat bath algorithm to equilibrate XY spins; using this in conjunction with the standard parallel tempering and overrelaxation sweeps, we carry out large scale Monte Carlo simulations. For $\sigma=0.6$ which is in the mean-field regime, we find clear evidence for an AT line. For $\sigma = 0.75$, there is evidence from finite size scaling studies for an AT transition but for $\sigma = 0.85$, the evidence for a transition is non-existent. We have also studied these systems at fixed temperature varying the field and discovered that at both $\sigma = 0.75$ and at $\sigma =0.85$ there is evidence of an AT transition! Confusingly, the correlation length and spin glass susceptibility as a function of the field are both entirely consistent with the predictions of the droplet picture and hence the non-existence of an AT line. The evidence from our simulations points to the complete absence of the AT line in dimensions outside the mean-field region and to the correctness of the droplet picture. Previous simulations which suggested there was an AT line can be attributed to the consequences of studying systems which are just too small. The collapse of our data to the droplet scaling form is poor for $\sigma = 0.75$ and to some extent also for $\sigma = 0.85$, when the correlation length becomes of the order of the length of the system, due to the existence of excitations which only cost a free energy of $O(1)$, just as envisaged in the TNT picture of the ordered state of spin glasses. However, for the case of $\sigma = 0.85$ we can provide evidence that for larger system sizes, droplet scaling will prevail even when the correlation length is comparable to the system size.Comment: 23 pages, 15 figure