Automatic Time Series Forecasting: The forecast Package for R

Automatic forecasts of large numbers of univariate time series are often needed in business and other contexts. We describe two automatic forecasting algorithms that have been implemented in the forecast package for R. The first is based on innovations state space models that underly exponential smoothing methods. The second is a step-wise algorithm for forecasting with ARIMA models. The algorithms are applicable to both seasonal and non-seasonal data, and are compared and illustrated using four real time series. We also briefly describe some of the other functionality available in the forecast package.

Automatic time series forecasting: the forecast package for R.

Automatic forecasts of large numbers of univariate time series are often needed in business and other contexts. We describe two automatic forecasting algorithms that have been implemented in the forecast package for R. The first is based on innovations state space models that underly exponential smoothing methods. The second is a step-wise algorithm for forecasting with ARIMA models. The algorithms are applicable to both seasonal and non-seasonal data, and are compared and illustrated using four real time series. We also briefly describe some of the other functionality available in the forecast package.ARIMA models; automatic forecasting; exponential smoothing; prediction intervals; state space models; time series, R.

Cultural Identities in Sustaining Religious Communities in the Arctic Region: An Ethnographic Analysis on Religiosity from the Northern Viewpoint

Northern countries are facing the challenges of declining human capital, and admitting immigrants, many of whom belong to religious minorities, to satisfy the demand for labour. If northern societies accept multiculturalism and immigrants, they should not disregard the cultures and religious practices (for example, ritual slaughter) of immigrants, as they need to survive and integrate as a minority community in a secular society. However, there is clash between secularism and religions permitting animal slaughter, which is prohibited by some and allowed by other European countries. Community viability and sustainability depend partly on the exercise of community beliefs and ideology that support identity behaviour. This study will present an ethnographic analysis of the religiosity related to ritual slaughter and Muslim cultural identity in the European Arctic region and explore how religious relativism and practice sustain the community and support the overall integration of the Muslim minority in the North

Development of a long-term climatology of tropical 1 cyclones and depressions for the South Pacific 2 Ocean basin

Tropical cyclones (TCs) are one of the most destructive synoptic systems that can cause enormous loss of life and property damages in the South Pacific Island nations. The impact of tropical depressions (TDs, i.e., weaker systems that do not develop into TCs) can also be staggering in the region in terms of heavy flooding and landslides, but a lack of complete records (reliable data prior to 1950) often hinders research involving TD impacts. A methodology has been developed here to detect TDs in the ERA-5 (the fifth generation European Centre for Medium-Range Weather Forecasts-ECMWF atmospheric reanalysis of the global climate) and 20CR (the Twentieth Century Reanalysis) dataset using the Okubo–Weiss–Zeta parameter (OWZP) detection scheme. The new South Pacific Enhanced Archive for Tropical Cyclones dataset (SPEArTC), the Dvorak analysis of satellite-based cloud patterns over the South Pacific Ocean basin, rainfall dataset for various stations in the South Pacific and historical archives have been utilised to validate ERA5/20CR-derived TCs and TDs. Results indicate that the OWZP method shows substantial skill in capturing the realistic climatological distribution of TCs and TDs for the South Pacific Ocean in both reanalyses dataset. The 20CR-derived TCs and TDs resemble several key characteristics of the observational records, including spatial distribution of genesis locations and track shapes. This gives us confidence that the 20CR-derived long-term records of TCs and TDs can serve as an effective tool for examining historical changes in various characteristics of TCs and TDs, particularly in the context of anthropogenic climate change. Utilizing the reconstructed proxies of TCs and TDs, their climatic connections with the El Niño Southern Oscillation (ENSO), the Interdecadal Pacific Oscillation (IPO), and the combined ENSO-IPO phases have been examined. Results show clear spatial shifts in TC activity between La Niña and El Niño phases with activity in the region 1400-1700E (1700-2200E) occurring during La Niña (El Niño) events. However, when IPO is considered synergistically with ENSO phases, we found that the combination of El Niño and the positive phase of IPO (+IPO) substantially enhances TC numbers (may be artifact influence) in both domains, noting the modulation between the two phases themselves. Similarly, La Niña and the negative phase of the IPO (-IPO) is found to enhance TC numbers in 1400-1700E. It is shown for the first time that the combined phases of El Niño and +IPO account for increased TC activity, as opposed to the combined phase of La Niña and -IPO, in the eastern sub-region. Similarly, the combined phase of La Niña and +IPO, as opposed to the combined phase of El Niño and -IPO, account for increased TC activity in the western sub-region. However, unlike TCs, the patterns of ENSO variability seem to be reversed for TDs. Changes in large-scale environmental conditions, such as environmental vertical wind shear, low-level cyclonic relative vorticity, mid-tropospheric relative humidity and sea surface temperature are linked to the various modes of variability patterns and their synergistic relationships. Results can have substantial implications, particularly on the predictability of TCs and TDs associated with the two important modes of natural variability in the South Pacific.Doctor of Philosoph

FUNCTIONAL ANTIBACTERIAL SURFACES MADE BY ULTRAFINE POWDER COATING

Surface bio-contamination is a serious problem which contributes to outbreaks of nosocominal infection. An effective antimicrobial surface coating can significantly reduce the average surface population of pathogens available for transmission to a susceptible host. To respond to these problems, a functional antibacterial surface has been developed. For the use in medical devices, food industries, aviation sector and many other areas, a strong antibacterial property is required for the surface coating to effectively resist bacterial colonization. Recently, the introduction of new silver based antibacterial surfaces has drawn more attention not only for their non-toxicity of the activeAg ion to human cells but also of their novel ability of being a long lasting biocide. A synthetic zeolite and three other natural zeolites have been selected in this work as carrier materials for silver. Silver acts as the active material that is incorporated within zeolite and blended with ultrafme polyester resin. It shows strong antibacterial properties against Escherichia coli. A commercially available sample has been selected to compare with all the experimental results. ICP-OES analysis shows the highest silver concentration being within the ion exchanged synthetic zeolite. Different polyester ultrafme powders have made with different ion exchanged zeolites and their antimicrobial efficacy tested by repeated use of the same coated chips followed by washing with liquid detergent and water. For final formulation, silver was incorporated into natural zeolite LBN (chabazite) through ion exchange with 0.05M silver nitrate for 24 hours at pH below 5.0 and IPC-OES analysis confirmed the amount of silver as 0.52% in the ultrafme coating powder. SEM and EDX analysis also show the uniform distribution and amount of silver within the coating respectively. The durability of coated chips show more than 99% reduction of microorganism even after ten consecutive uses. The coated chips were also characterized by checking the effectiveness against autoclave tests and accelerated weather tests as well as the antibacterial efficiency for each condition. For high efficiency, the coating needs to have a certain amount of active component. The controlled silver release capability of the formulated coating with this concentration of silver is promising compared to the commercial counter parts. These coated surfaces have shown uniform homogeneous antibacterial properties with excellent durability for extended period

Study of Extensions to the Linear Sampling Method for Electromagnetic Inverse Scattering

The linear sampling method (LSM) is a simple and effective qualitative method to reconstruct the support of unknown object by solving inverse scattering problem. The solution is done based on the field radiated by the elementary source located in a set of test points. In this thesis, the LSM formulation, limitations of standard LSM and extensions of LSM are discussed. Standard LSM can reconstruct simply connected objects, but it fails in case of concave or not simply connected objects. However, it can reconstruct the convex hull for such objects. Some extensions to LSM have been proposed to avoid these limitations. Two of these extensions are generalized LSM (GLSM) and multipole based LSM (MLSM). GLSM is formulated by generalizing the right side of the linear equation to higher order multipoles. This provides more information about the radiated field. The reconstruction is even better by using some post-processing scheme such as a modified indicator function and higher values for the regularization parameter. But GLSM cannot reconstruct the actual shape for some complex objects. MLSM is based on physical regularization. This method analyzes the multipole expansion of the scattered field. Only monopole and dipole terms are used for the reconstruction. This modification shows better reconstruction than the mathematical regularization in GLSM. Another advantage of MLSM is that the threshold for boundary contour is constant for all types of objects. From the results, it is evident that MLSM is somewhat better than GLSM when the object’s complex hull is very different than the object itself. However, higher permittivity affects the solutions. It can be avoided by using higher value of regularization parameter in GLSM but in MLSM there is no known remedy

Analysis and Interactive Visualization of Software Bug Reports

A software Bug report contains information about the bug in the form of problem description and comments using natural language texts. Managing reported bugs is a significant challenge for a project manager when the number of bugs for a software project is large. Prior to the assignment of a newly reported bug to an appropriate developer, the triager (e.g., manager) attempts to categorize it into existing categories and looks for duplicate bugs. The goal is to reuse existing knowledge to fix or resolve the new bug, and she often spends a lot of time in reading a number of bug reports. When fixing or resolving a bug, a developer also consults with a series of relevant bug reports from the repository in order to maximize the knowledge required for the fixation. It is also preferable that developers new to a project first familiarize themselves with the project along with the reported bugs before actually working on the project. Because of the sheer numbers and size of the bug reports, manually analyzing a collection of bug reports is time-consuming and ineffective. One of the ways to mitigate the problem is to analyze summaries of the bug reports instead of analyzing full bug reports, and there have been a number of summarization techniques proposed in the literature. Most of these techniques generate extractive summaries of bug reports. However, it is not clear how useful those generated extractive summaries are, in particular when the developers do not have prior knowledge of the bug reports. In order to better understand the usefulness of the bug report summaries, in this thesis, we first reimplement a state of the art unsupervised summarization technique and evaluate it with a user study with nine participants. Although in our study, 70% of the time participants marked our developed summaries as a reliable means of comprehending the software bugs, the study also reports a practical problem with extractive summaries. An extractive summary is often created by choosing a certain number of statements from the bug report. The statements are extracted out of their contexts, and thus often lose their consistency, which makes it hard for a manager or a developer to comprehend the reported bug from the extractive summary. Based on the findings from the user study and in order to further assist the managers as well as the developers, we thus propose an interactive visualization for the bug reports that visualizes not only the extractive summaries but also the topic evolution of the bug reports. Topic evolution refers to the evolution of technical topics discussed in the bug reports of a software system over a certain time period. Our visualization technique interactively visualizes such information which can help in different project management activities. Our proposed visualization also highlights the summary statements within their contexts in the original report for easier comprehension of the reported bug. In order to validate the applicability of our proposed visualization technique, we implement the technique as a standalone tool, and conduct both a case study with 3914 bug reports and a user study with six participants. The experiments in the case study show that our topic analysis can reveal useful keywords or other insightful information about the bug reports for aiding the managers or triagers in different management activities. The findings from the user study also show that our proposed visualization technique is highly promising for easier comprehension of the bug reports