Search results for "Computer science"
showing 10 items of 22367 documents
Understanding beginners' mistakes with Haskell
2015
AbstractThis article presents an overview of student difficulties in an introductory functional programming (FP) course taught in Haskell. The motivation for this study stems from our belief that many student difficulties can be alleviated by understanding the underlying causes of errors and by modifying the educational approach and, possibly, the teaching language accordingly. We analyze students' exercise submissions and categorize student errors according to compiler error messages and then manually according to the observed underlying cause. Our study complements earlier studies on the topic by applying computer and manual analysis while focusing on providing descriptive statistics of d…
On the motivations to enroll in doctoral studies in Computer Science — A comparison of PhD program models
2013
While student motivation has been intensively researched, only a few studies cover motivation at doctoral level and even less focus on doctoral education in Computer Science. In this paper we investigate the motivation of graduate students to pursue doctoral studies specifically in Computer Science. We interviewed 63 doctoral students, from two different doctoral models (traditional and structured) in Finland and Austria, on their initial reasons and experiences that led them to enroll in doctoral studies. We identified five disjoint main motivational drivers that relate with different aspects of extrinsic and intrinsic motivation. Together with a measure of the strength of their initial mo…
A modelling framework for social media monitoring
2013
This paper describes a hierarchical, three-level modelling framework for monitoring social media. Immediate social reality is modelled through the first level of the models. They represent various virtual communities at social media sites and adhere to the social world models of the sites, i.e., the "site ontologies". The second-level model is a temporal multirelational graph that captures the static and dynamic properties of the first-level models from the perspective of the monitoring site. The third-level model consists of a temporal relational database scheme that models the temporal multirelational graph within the database. The models are specified and instantiated at the monitoring s…
A Generic Architecture for a Social Network Monitoring and Analysis System
2011
This paper describes the architecture and a partial implementation of a system designed for the monitoring and analysis of communities at social media sites. The main contribution of the paper is a novel system architecture that facilitates long-term monitoring of diverse social networks existing and emerging at various social media sites. It consists of three main modules, the crawler, the repository and the analyzer. The first module can be adapted to crawl different sites based on ontology describing the structure of the site. The repository stores the crawled and analyzed persistent data using efficient data structures. It can be implemented using special purpose graph databases and/or …
Twister Tries
2015
Many commonly used data-mining techniques utilized across research fields perform poorly when used for large data sets. Sequential agglomerative hierarchical non-overlapping clustering is one technique for which the algorithms’ scaling properties prohibit clustering of a large amount of items. Besides the unfavorable time complexity of O(n 2 ), these algorithms have a space complexity of O(n 2 ), which can be reduced to O(n) if the time complexity is allowed to rise to O(n 2 log2 n). In this paper, we propose the use of locality-sensitive hashing combined with a novel data structure called twister tries to provide an approximate clustering for average linkage. Our approach requires only lin…
Interface Detection Using a Quenched-Noise Version of the Edwards-Wilkinson Equation
2015
We report here a multipurpose dynamic-interface-based segmentation tool, suitable for segmenting planar, cylindrical, and spherical surfaces in 3D. The method is fast enough to be used conveniently even for large images. Its implementation is straightforward and can be easily realized in many environments. Its memory consumption is low, and the set of parameters is small and easy to understand. The method is based on the Edwards-Wilkinson equation, which is traditionally used to model the equilibrium fluctuations of a propagating interface under the influence of temporally and spatially varying noise. We report here an adaptation of this equation into multidimensional image segmentation, an…
Teaching programming by emphasizing self-direction: How did students react to the active role required of them?
2013
Lecturing is known to be a controversial form of teaching. With massed classrooms, in particular, it tends to constrain the active participation of students. One of the remedies applied to programming education is to use technology that can vitalize interaction in the classroom, while another is to base teaching increasingly on programming activities. In this article, we present the first results of an exploratory study, in which we teach programming without lectures, exams, or grades, by heavily emphasizing programming activity, and, in a pedagogical sense, student self-direction. This article investigates how students reacted to the active role required of them and what issues emerged in …
Comparing the cost-efficiency of CoAP and HTTP in Web of Things applications
2014
Abstract Constrained Application Protocol (CoAP) has been introduced as a simpler alternative to the Hypertext Transfer Protocol (HTTP) for connecting constrained smart objects to the Web. The adoption of the protocol depends on its relative advantage, and the cost–benefit associated with the use of the protocol is a significant factor affecting a protocol adoption decision. This paper aims at deepening the understanding of the cost–benefits of CoAP and identifies the application scenarios where its use is likely to be economically justifiable. The paper analyzes the costs of using CoAP and HTTP in the Web of Things (WoT) applications, by identifying the components of the total cost of owne…
Investigating serendipity in recommender systems based on real user feedback
2018
Over the past several years, research in recommender systems has emphasized the importance of serendipity, but there is still no consensus on the definition of this concept and whether serendipitous items should be recommended is still not a well-addressed question. According to the most common definition, serendipity consists of three components: relevance, novelty and unexpectedness, where each component has multiple variations. In this paper, we looked at eight different definitions of serendipity and asked users how they perceived them in the context of movie recommendations. We surveyed 475 users of the movie recommender system, MovieLens regarding 2146 movies in total and compared tho…
A Hybrid Multigroup Coclustering Recommendation Framework Based on Information Fusion
2015
Collaborative Filtering (CF) is one of the most successful algorithms in recommender systems. However, it suffers from data sparsity and scalability problems. Although many clustering techniques have been incorporated to alleviate these two problems, most of them fail to achieve further significant improvement in recommendation accuracy. First of all, most of them assume each user or item belongs to a single cluster. Since usually users can hold multiple interests and items may belong to multiple categories, it is more reasonable to assume that users and items can join multiple clusters (groups), where each cluster is a subset of like-minded users and items they prefer. Furthermore, most of…