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Predictive Reasoning in Subjective Bayesian Networks
Get PDFSubjective Bayesian networks extend Bayesian networks by substituting the conditional probability distributions with subjective opinions. In that way they enable explicit representation of the uncertainty in the probabilistic information encoded in the network. In this paper we focus on predictive reasoning in subjective Bayesian networks and propose an inference method that is based on the operations of deduction and multiplication of subjective opinions. We demonstrate modelling and inference with subjective Bayesian networks through an example.
viSQLizer: Using visualization for learning SQL
Get PDFStructured Query Language (SQL) is used for interaction between database technology and its users. In higher education, students often struggle with understanding the underlying logic of SQL, thus have trouble with understanding how and why a result table is created from a query. A prototype of a visual learning tool for SQL, viSQLizer, has been developed to determine if visualizations could help students create a mental model and thus enhance their understanding of the underlying logic of SQL. Trough the use of animations and decomposing, our results indicate that visualizations might give students a better understanding of the underlying logic, and that students gain the same learning outcome through visualizations as when using an online tutorial with explanatory text and exercises. Feedback from both professors and students from conducted interviews and experiments indicate that the tool could be used by professors as a visualization tool in lectures, and by students as a practical tool; not as a replacement of, but as an addition to traditional teaching methods
Introducing Selective Undo Features in a Collaborative Editor
Get PDFUndo is an important functionality of editors. Selective undo is widely regarded as an important feature for collaborative editing. However, even after nearly three decades of active research and development, there is still no practical support of selective undo for collaborative editing. This paper introduces the selective undo features that we have implemented as part of a collaborative editing subsystem in the GNU Emacs text editor
RescUSim and IPython: An environment for offshore emergency preparedness planning
Get PDFEmergency preparedness is crucial for oil and gas operators. While accidents in this industry are commonly connected to oil spill disasters, helicopter accidents are, in terms of incidence rates, a more grave concern in Norway. A recent helicopter accident near Bergen has brought this subject back into focus. We introduce RescUSim, a simulator for rescue missions after offshore helicopter accidents, which is implemented as an open source library with bindings for the Python language. We discuss the modules in the existing Python ecosystem that are used for data preparation and analysis. We show how RescUSim and the interactive computing environment IPython can join forces to provide a tool for planning rescue preparedness for oil and gas related offshore activities
Clustering Methods for Electricity Consumers: An Empirical Study in Hvaler - Norway
Get PDFThe development of Smart Grid in Norway in specific and Europe/US in general will shortly lead to the availability of massive amount of fine-grained spatio-temporal consumption data from domestic households. This enables the application of data mining techniques for traditional problems in power system. Clustering customers into appropriate groups is extremely useful for operators or retailers to address each group differently through dedicated tariffs or customer-tailored services. Currently, the task is done based on demographic data collected through questionnaire, which is error-prone. In this paper, we used three different clustering techniques (together with their variants) to automatically segment electricity consumers based on their consumption patterns. We also proposed a good way to extract consumption patterns for each consumer. The grouping results were assessed using four common internal validity indexes. We found that the combination of Self Organizing Map (SOM) and k-means algorithms produces the most insightful and useful grouping. We also discovered that grouping quality cannot be measured effectively by automatic indicators, which goes against common suggestions in literature
Reusable Multi-selection in Touch-Screen User Interfaces
Get PDFMulti-selection is the act of selecting a set of elements in a graphical user interface in order to perform an operation on that set. Examples of multi-selection are selecting thumbnails in an image gallery or files on a file explorer. Whether and how multi-selection is supported in different applications varies widely, which leaves user experiences wanting. Järvi and Parent recently introduced an abstract model of multi-selection that helps programmers to implement multi-selection uniformly and correctly in desktop GUIs. This paper adapts the model to touch-screen devices. We present the rationale for choosing particular gestures for selection commands and explain how they map to the original model. A user study comparing our selection model with the established multi-selection features used by major Android and iOS applications shows that our selection feature allows for the fastest and most accurate selection
LEGO Mindstorms og MATLAB; anvendt matematikk/fysikk og programmering i skjønn forening
Get PDFVed å kombinere LEGO Mindstorms og MATLAB kan studenter introduseres for programmering på en måte som i stor grad er prosjektbasert og som innebærer såkalt studentaktiv læring. Denne artikkel beskriver hvordan Universitetet i Stavanger benytter denne kombinasjonen for data- og elektrostudenter i første semester som en del av Ingeniørfaglig innføringsemne. Det blir også beskrevet hvordan studentene blir organisert i grupper og hvilke forutsetninger som må til for at én faglig ansvarlig skal kunne veilede 160 studenter og gi faglige tilbakemeldinger til samtlige. Videre beskrives hvordan det tilrettelegges for å oppnå individuell læring i gruppearbeidet. Programmeringen er knyttet opp mot praktiske anvendelser fra fysikken som gjør bruk av anvendt matematikk i form av blant annet numerisk integrasjon, filtrering og numerisk derivasjon. Dette åpner for mange motiverende prosjekter som studentene har stor glede av å gjennomføre
Dynamic virtualization of AliEn grid jobs using the Vmbatch system
Get PDFThe Vmbatch system is shown to be a robust and reliable system for running batch jobs inside virtual machines. The system has been developed as a lightweight tool to establish and clean up virtual machines for CernVM processing of ALICE grid jobs. It can work with a stock guest image and interfaces with the Torque batch system.
With the use of virtualization, the system can create a homogeneous execution environment for grid jobs that can be expanded dynamically upon availability of generic computing resources
Improving the Canny Edge Detector Using Automatic Programming: Improving Hysteresis Thresholding
Get PDFWe have used automatic programming to improve the hysteresis thresholding stage of the popular Canny edge detector—without increasing the computational complexity or adding extra information. The F-measure has been increased by 1.8% on a test set of natural images, and a paired student-t test and a Wilcoxon signed rank test show that the improvement is statistically significant.
This is the first time evolutionary computation and automatic programming has been used to improve hysteresis thresholding. The new program has introduced complex recursive patterns that make the algorithm perform better with weak edges and retain more detail.
The findings provide further evidence that an automatically designed algorithm can outperform manually created algorithms on low level image analysis problems, and that automatic programming is ideally suited for inferring suitable heuristics for such problems