What Do the Sun and the Sky Tell Us About the Camera?

As the main observed illuminant outdoors, the sky is a rich source of information about the scene. However, it is yet to be fully explored in computer vision because its appearance in an image depends on the sun position, weather conditions, photometric and geometric parameters of the camera, and the location of capture. In this paper, we analyze two sources of information available within the visible portion of the sky region: the sun position, and the sky appearance. By fitting a model of the predicted sun position to an image sequence, we show how to extract camera parameters such as the focal length, and the zenith and azimuth angles. Similarly, we show how we can extract the same parameters by fitting a physically-based sky model to the sky appearance. In short, the sun and the sky serve as geometric calibration targets, which can be used to annotate a large database of image sequences. We test our methods on a high-quality image sequence with known camera parameters, and obtain errors of less that 1% for the focal length, 1° for azimuth angle and 3° for zenith angle. We also use our methods to calibrate 22 real, low-quality webcam sequences scattered throughout the continental US, and show deviations below 4% for focal length, and 3° for the zenith and azimuth angles. Finally, we demonstrate that by combining the information available within the sun position and the sky appearance, we can also estimate the camera geolocation, as well as its geometric parameters. Our method achieves a mean localization error of 110 km on real, low-quality Internet webcams. The estimated viewing and illumination geometry of the scene can be useful for a variety of vision and graphics tasks such as relighting, appearance analysis and scene recovery.     

What do we do now? Workflows for an unpredictable world

Workflow systems permit organization of many individual subtasks into a cohesive whole, in order to accomplish a specific mission. For many government and business missions, these systems are used to manage repetitive processes, such as large data-processing and exploitation pipelines. Government missions with strong interactions with the real world are extremely dynamic, as are all missions dealing with error-prone or changing data streams. We contribute a vision for discovery of new steps in adaptive workflow systems, suitability functions that can discover candidate alternatives, and a way forward for sourcing options for decision-makers, without the strong assumptions required by previous work. As data-processing workflows are shared, the sharing entities may find that certain parts of the workflow must be adapted to the new environment of mission. Extremely dynamic environments call for capabilities that support agile operations and pipeline sharing by making it possible to choose relevant actions when a situation invalidates the assumptions of current execution. We adapt some work in schema matching towards this problem, citing key differences between the two sets of challenges.     

DEI in the IS discipline: What can we do better?

Recent diversity, equity, and inclusion (DEI) efforts have made some limited progress in addressing underrepresentation and unequal opportunities for minority members in the Information Systems (IS) academic community. The Association for Information Systems (AIS), as the preeminent global professional society for the IS discipline, is tasked with acting on behalf of its members and their colleagues to achieve equity and inclusion for its diverse membership. This editorial has two aims: (1) to share the extent to which positive changes have been made and also the extent to which underrepresentation still pervades the IS academic community, especially at the senior ranks and in positions of power, and (2) to propose a coordinated, strategic focus that our field, our journals and conferences, and our association (AIS) can take to further improve diversity and inclusion for both junior and senior minority colleagues.     

Evaluation of the Dutch subsurface geoportal: What lies beneath?

This paper focuses on a geoportal from a “what lies beneath” perspective. It analyses processes of budgeting, planning, monitoring, performance measurement, and reporting of the national initiative titled Digital Information of the Dutch Subsurface (known by its Dutch acronym, DINO). The study is used as a means to empirically refine a conceptual model that illuminates how external agents influence or control the coordination of geo-information in the public sector. DINO is developed and maintained in a formal principal-agent relationship with clear objectives and accountability. DINO is managed by the Netherlands Institute of Applied Geoscience (the agent) through a performance-based management contract with the sponsoring Geo-Information Commission (the principals). The DINO program is characterized by the pooling of financial resources from five ministries, the internal tracking of activity progression, the routine reporting to the user community, and the regular monitoring and evaluation of DINO by the Geo-Information Commission. The case study reveals that ‘soft’ rather than ‘hard’ controls are used and that ‘mutual shaping’ takes place, with the agent influencing how it is ‘controlled’ by the principal. However, the management contract still relies on a power disparity and reinforces previous research findings that external parties can influence network/coordination conditions. In-depth case studies such as this work can increase understanding of evaluation in the context of politico-administrative processes and improve researchers’ ability to critically compare geoportal initiatives.     

What have examinations got to do with computers in education?

Abstract   Courseware, i.e. computer based learning materials, usually includes some self-assessment for formative assessment. Insufficient attention has been paid, however, to the link between formal assessment and use of courseware: teachers and learners focus on examination syllabuses. Examinations bodies can use only the simplest forms of ICT-based assessment (objective or multiple choice tests) until learners are familiar with newer styles. This problem can be addressed on several fronts: with new ICT styles of tests, by developing websites supporting learners and teachers, by conducting field trials using computers under examination conditions and by commissioning new types of examination questions built around online interactive simulations.     

Canadian university students in wireless classrooms: What do they do on their laptops and does it really matter?

Two studies were conducted to examine what undergraduate students do on their laptops during class time and the extent to which laptop usage behaviors are associated with academic success. In Study 1, a sample of 1129 students from a Canadian university completed a survey measuring prototypical behaviors emitted on laptops during class time. Results of factor analyses indicated that laptop behaviors can be regrouped in two dimensions: School related and school unrelated laptop utilization. School unrelated laptop behaviors were significantly associated with lower levels of self-reported academic achievement and satisfaction. School related laptop behaviors were positively associated with academic satisfaction. These results were invariant across different faculties on campus. In Study 2, another sample of 88 students was recruited to examine the longitudinal association between laptop behaviors and semester grade point average obtained at the end of the semester. Results of Study 2 showed that school unrelated laptop behaviors were prospectively associated with lower semester grade point average, even after controlling for a series of potentially confounding influences (i.e., self-regulation failure, motivational deficit, disorganized learning, internet addiction, and school disenchantment). Overall, these results provide theoretically important support to suggest that in-class laptop utilization is a unique and contemporary mode of learning that should not be treated as an epiphenomenon merely accountable and reducible to other sources of psychological influences.     

How do we encourage an egoist to act socially in an ad hoc mobile network?

We consider a flow-based model for an ad hoc mobile network where users may need to use transit nodes in order to be able to communicate. Under the assumption that every node is willing to cooperate, we derive the set of Karush–Kuhn–Tucker equations that define the socially-optimal flows on each of the routes. We then look at the problem from an ‘egoist’ point of view, in which the user at node i cares only about maximising his/her utility under the constraint that the flows on routes which do not use node i are fixed at the socially-optimal value.This leads us to a consideration of extra constraints that could be introduced to induce the egoist user at node i to behave in a socially-optimal way. We show how to derive the parameters of such constraints, and give them interpretations in terms of schemes in which nodes’ transmission rates are constrained by the rates at which they accumulate ‘credit’.     

What do students do in a F2F CSCL classroom? The optimization of multiple communications modes

This exploratory study analyzes how students use different communication modes to share information, negotiate meaning and construct knowledge in the process of doing a group learning activity in a Primary Grade 5 blended learning environment in Singapore. Small groups of students interacted face-to-face over a computer-mediated communication (CMC) technology called Group Scribbles (GS) to jointly complete a learning task. The lesson designers attempted to optimize the use of CMC technology and face-to-face (F2F) discussion in students’ collaborative learning, with the aim of harnessing the specific features of each medium. Building on notions from communication studies and from interaction analysis, we observed the construction and evolution of the interactions through analyzing the artifacts that were produced by a group of students – in verbal talk, gestures, and sketches drawn and text inscribed in GS. F2F and GS interactions intertwined to support collaborative learning. The findings from this study could inform design aspects concerning integrating and reinforcing the strengths of both communication modes when introducing computer-assisted collaborative learning (CSCL) in a F2F classroom.     

Integration of Usability Evaluation Studies via a Novel Meta-Analytic Approach: What are Significant Attributes for Effective Evaluation?

The overall discovery rates, which are the ratios of sum of unique usability problems detected by all experiment participants against the number of usability problems existed in the evaluated systems, were investigated to find significant factors of usability evaluation through a meta-analytic approach with the n-corrected effect sizes newly defined in this study. Since many studies of usability evaluation have been conducted under specific contexts showing some mixed findings, usability practitioners need holistic and more generalized conclusions. Due to the limited applicability of the traditional meta-analysis to usability evaluation studies, a new meta-analytic approach was established and applied to 38 experiments that reported overall discovery rates of usability problems as a criterion measure. Through the meta-analytic approach with the n-corrected effect sizes, we successfully combined 38 experiments and found evaluator's expertise, report type, and interaction between usability evaluation method and time constraint as significant factors. We suggest that in order to increase overall discovery rates of usability problems, (a) free-style written reports are better than structured written reports; (b) when heuristic evaluation or cognitive walkthrough is used, the usability evaluation experiments should be conducted without time constraint, but when think-aloud is used, time constraint is not an important experimental condition; (c) usability practitioners do not need to be concerned about unit of evaluation, fidelity of evaluated systems, and task type; and (d) HCI experts are better than novice users or evaluators. Our conclusions can guide usability practitioners when determining evaluation contexts, and the meta-analytic approach of this study provides an alternative way to combine the empirical results of usability evaluation besides the traditional meta-analysis.     

Implementation issues in optimization algorithms: do they matter?

Two factors that have a major impact on the performance of an optimization method are (1) formal algorithm specifications and (2) practical implementations. The impact of the latter is typically ignored, although it defines the results measured in experiments. We present an in-depth study of algorithm implementation issues and ask questions such as Does optimizing the implementation of an optimization algorithm pay off? Do bugs matter? and Is using more complicated but also more efficient data structures worth the effort? The intuitive answer to all of these questions is yes, but there is little published evidence. To bridge this gap, we use one of the most studied combinatorial optimization problems – the Traveling Salesman Problem – as a test bed and implement two state-of-the-art approaches for solving it – the Lin-Kernighan Heuristic and an Ejection Chain Method. We investigate implementation effort and performance gain, in order to provide further insights to the above questions.     

How do entrepreneurs learn and engage in an online community-of-practice? A case study approach

This paper investigates the ways in which entrepreneurs use communities of practice (CoPs) to express themselves, using narrative theory and rhetorical analysis, to gain insight into an electronic social network medium, namely, YoungEntrepreneur.com. In particular, the study focuses on CoPs themes, including why entrepreneurs engage in CoPs, what role the moderators and resident entrepreneurs can play in managing online CoPs, on communication rituals of the knowledge sharing through interactivity, and on ‘how to develop an intervention’ to maintain and stimulate entrepreneurs for engaging in an online community. Findings reveal that the topic title plays a major role in attracting people. Successful topics with successful conclusions (in terms of the original query that was answered) will not necessarily get high responses and vice versa. It is observed that the domain expert does not play a big role in keeping the discussion going. Finally, the study also discovered that entrepreneurs like to communicate in a story telling genre. A comprehensive set of engagement measurement tools are introduced to effectively measure the engagement in a virtual CoP, along with a classification to define and categorise discourse of messages in terms of content and context, which allow practitioners to understand the effectiveness of a social networking site.     

Mobile Technology in the Classroom: What Drives Student-Lecturer Interactions?

Online learning when combined with mobile technology transforms the traditional classrooms from teacher-centered to student-centered classrooms. Despite the widespread use of mobile technology among students and educators today, limited researches have been conducted to study the effects of using mobile technology to enhance student–lecturer interactions. In addition, existing theories of technology acceptances, chiefly Information System Success Model (ISSM), Motivational Model (MM), Social Cognitive Theory (SCT), Technology Acceptance Model (TAM), and Cultural Dimension Theory (CDT) are widely recognized for their predictive power in determining adoption intentions. In this study, determinants from all five theories were unified and examined, namely system quality and information quality from ISSM, enjoyment from MM, perceived usefulness and perceived ease of use from TAM, self-efficacy from SCT, and uncertainty avoidance from CDT as predictors of adoption intention in the context of predicting student–lecturer interactions. This empirical study was conducted using an online survey. Data collected from the samples (n = 328) were analyzed using PLS-SEM. Results obtained exhibited adequate explanatory power, where information quality, system quality, enjoyment, and uncertainty avoidance significantly predict adoption intention, while perceived usefulness, perceived ease of use, and self-efficacy were insignificant. Secondly, each theory was independently analyzed, and the predictive power and relevance of ISSM, MM, TAM, and UDT confirmed the importance and relevance of these theories. Results obtained provided a comprehensive understanding of the factors that significantly affect students’ intentions to use mobile technology to interact with their lecturers on academic matters. The discussions and implications of this study are crucial for researchers and practitioners of educational technologies in higher education.     

“What do they snapchat about?” Patterns of use in time-limited instant messaging service

The use of Snapchat – a time-limited instant messaging service – has been rapidly rising amongst adolescents. However, the exact nature of Snapchat use remains difficult to examine due to the self-destructive nature of content sent and received via this service. We report an online survey conducted with the use of a memory sampling method to enquire about the specific details of the very last image or video each participant sent and received via Snapchat. We found that users mainly share ‘selfies’, typically embed text and ‘doodles’ with photos they share, use it mostly at home, and primarily for communication with close friends and family as an ‘easier and funnier’ alternative to other instant messaging services. We also found that high intensity of Snapchat use was more associated with bonding rather than bridging social capital. We discuss those findings in the context of existing studies on the use of instant messaging services and social networking sites.     

The Identification of Spelling Variants in English and German Historical Texts: Manual or Automatic?

In this article, we describe the respective approaches we havetaken when addressing issues of spelling variation in Germanand English historical texts. More specifically, we describean experiment to evaluate automatic techniques for the developmentof letter replacement heuristics against manually created goldstandards of known letter replacements rules. As will becomeclear, the motivation for the research differs according tothe team of researchers: the German researchers are seekingto develop a search engine for historical texts; the Englishresearchers want to improve the results obtained when applyingcorpus linguistic techniques (developed for modern language)to historical data. However, the respective teams do share alonger term goal of assessing whether it is possible to developa generic spelling detection tool for Indo-European languages.     

What does information technology “do” to business communications?: Two empirical studies

According to recent surveys, communication skills are among the most important areas of managerial performance. With the widespread use of information technology, end users are producing large amounts of written communications. Yet suprisingly little empirical research has been conducted to determine the effects of information technology on business communications. Reported here are two studies, which focus on the effects of information technology on the structure of written communication, and the time required to read end-user generated versus traditionally generated compositions.Two views of the writing process and the role of information technology in it are the mediationist perspective (technology permits the text to be polished until it is of the highest quality) and the extentionist perspective (technology encourages open, natural composition which is conversational in tone). Our findings supported the latter view.Its effects on end-user composition include more composition time and document length. Thus, organizational efficiency (overall time savings) could decrease through the extensive use of end-user generated written communication.     

What seams do we remove in mobile-assisted seamless learning? A critical review of the literature

Seamless learning refers to the seamless integration of the learning experiences across various dimensions including formal and informal learning contexts, individual and social learning, and physical world and cyberspace. Inspired by the exposition by Chan et al. (2006) on the seamless learning model supported by the setting of one or more mobile device per learner, this paper aims to further investigate the meaning of seamless learning and the potential ways to put it in practice. Through a thorough review of recent academic papers on mobile-assisted seamless learning (MSL), we identify ten dimensions that characterize MSL. We believe that such a framework allows us to identify research gaps in the stated area. A practitioner interested in adopting an MSL design or doing a new design can use our analysis to situate the dimensional space where the constraints or parameters of his or her design problem lie, and look at relevant design and research-based evidence of other related MSL systems to refine her own design.     

Intrusion Detection Systems: What is intrusion detection and why do we need it?

In order to answer the opening question, it may help to consider the following scenario. Once upon a time there were isolated villages where everyone trusted everyone else. Little by little, people started to travel from village to village to exchange goods, news and information and life generally got better. A few people used the opportunity to travel from village to village to look inside other people’s houses and take things without permission. As this behaviour became more frequent, villagers began putting locks on their doors. But the criminal element (or in some cases the rabidly curious) was inspired to find ways around these locks. So the villages developed new ways of detecting intruders and monitoring what was taken. These methods included security guards, infra-red motion detectors and security cameras.     

“What do others think?” An emic approach to participatory action research in Bangladesh

AI & SOCIETY - Community informatics and Information and Communications Technology for Development research projects frequently focus on the appropriation of ICTs and the design of information...     

Matlab,Python, Julia: What to Choose in Economics?

Computational Economics - We perform a comparison of Matlab, Python and Julia as programming languages to be used for implementing global nonlinear solution techniques. We consider two popular...