Aimilia Tzanavari

Combining collaborative and Content-Based Filtering using Conceptual graphs

Collaborative Filtering and Content-Based Filtering are techniques used in the design of Recommender Systems that support personalization. Information that is available about the user, along with information about the collection of users on the system, can be processed in a number of ways in order to extract useful recommendations. There have been several algorithms developed, some of which we briefly introduce, which attempt to improve performance by maximizing the accuracy of their predictions. We describe a novel algorithm in which user models are represented as Conceptual Graphs and report on results obtained using the EachMovie dataset. We compare the algorithms based on the average error of prediction and standard deviation and discuss our method’s strengths and advantages.

Giving More Adaptation Flexibility to Authors of Adaptive Assessments

In this paper, we present AthenaQTI, a tool for authoring personalized assessments, which gives the author significant flexibility in terms of the adaptation that s/he can incorporate in the assessments s/he builds. We focus on presenting the functionality of the authoring environment and the tool’s conformance to the IMS- QTI specification, a fact that gives it the advantage of interoperability. Furthermore, we briefly describe the user model and the philosophy of its manipulation.

Effectiveness of an Immersive Virtual Environment (CAVE) for Teaching Pedestrian Crossing to Children with PDD-NOS

Children with Autism Spectrum Disorders (ASD) exhibit a range of developmental disabilities, with mild to severe effects in social interaction and communication. Children with PDD-NOS, Autism and co-existing conditions are facing enormous challenges in their lives, dealing with their difficulties in sensory perception, repetitive behaviors and interests. These challenges result in them being less independent or not independent at all. Part of becoming independent involves being able to function in real world settings, settings that are not controlled. Pedestrian crossings fall under this category: as children (and later as adults) they have to learn to cross roads safely. In this paper, we report on a study we carried out with 6 children with PDD-NOS over a period of four (4) days using a VR CAVE virtual environment to teach them how to safely cross at a pedestrian crossing. Results indicated that most children were able to achieve the desired goal of learning the task, which was verified in the end of the 4-day period by having them cross a real pedestrian crossing (albeit with their parent/educator discretely next to them for safety reasons).

Visualizing and Assessing Hypotheses for Marine Archaeology in a VR CAVE Environment

The understanding and reconstruction of a wrecks formation process can be a complicated procedure that needs to take into account many interrelated components. The team of the University of Cyprus investigating the 4th-century BC Mazotos shipwreck are unable to interact easily and intuitively with the recorded data, a fact that impedes visualization and reconstruction and subsequently delays the evaluation of their hypotheses. An immersive 3D visualization application that utilizes a VR CAVE was developed, with the intent to enable researchers to mine the wealth of information this ancient shipwreck has to offer. Through the implementation and evaluation of the proposed application, this research seeks to investigate whether such an environment can aid the interpretation and analysis process and ultimately serve as an additional scientific tool for underwater archaeology.

User Experience Observations on Factors That Affect Performance in a Road-Crossing Training Application for Children Using the CAVE

Each year thousands of pedestrian get killed in road accidents and millions are non-fatally injured. Many of these involve children and occur when crossing at or between intersections. It is more difficult for children to understand, assess and predict risky situations, especially in settings that they don’t have that much experience in, such as in a city. Virtual Reality has been used to simulate situations that are too dangerous to practice in real life and has proven to be advantageous when used in training, aiming at improving skills. This paper presents a road-crossing application that simulates a pedestrian crossing found in a city setting. Children have to evaluate all given pieces of information (traffic lights, cars crossing, etc.) and then try to safely cross the road in a virtual environment. A VR CAVE is used to immerse children in the city scene. User experience observations were made so as to identify the factors that seem to affect children’s performance. Results indicate that the application was well received as a learning tool and that gender; immersion and traffic noise seem to affect children’s performance.

Navigation in virtual reality: Comparison of gaze-directed and pointing motion control

We compared two locomotion techniques in an immersive CAVE-like display in order to determine which one promotes better performance in a wayfinding task. One method, commonly found in computer games, allows participants to steer through the 3D scene according to their gaze direction while the other uncouples the gaze direction from the direction of travel. In both cases tracked physical head movements determined the gaze direction. In order to provide a realistic scenario for comparing these methods we devised a task in which participants had to navigate to various houses of a virtual village that was previously seen on a map. The 2D coordinates of paths taken by participants were recorded together with their success rates in finding the targets, and the time taken to reach their destination. Participants showed better results with the pointing method of motion control, reaching the targets faster and with fewer errors. Results are interpreted with respect to the benefits afforded by large field of view displays.

ArchReco: a software tool to assist software design based on context aware recommendations of design patterns

This work describes the design, development and evaluation of a software Prototype, named ArchReco, an educational tool that employs two types of Context-aware Recommendations of Design Patterns, to support users (CS students or professionals) who want to improve their design skills when it comes to training for High Level Software models. The tool’s underlying algorithms take advantage of Semantic Web technologies, and the usage of Content based analysis for the computation of non-personalized recommendations for Design Patterns. The recommendations’ objective is to support users in functions such as finding the most suitable Design Pattern to use according to the working context, learn the meaning, objectives and usages of each Design Pattern. The current work presents the Semantic Modeling of the Software Design process through the definition of the context that defines the Software Design process and in particular the representation of the Design Patterns as Ontology model, the implemented Context Aware Recommendation Algorithms and the evaluation results extracted from a user based testing for the ArchReco prototype.

Reflecting on the Design Process for Virtual Reality Applications

ABSTRACT A reflective analysis on the experience of virtual environment (VE) design is presented focusing on the human–computer interaction (HCI) challenges presented by virtual reality (VR). HCI design guidelines were applied to development of two VRs, one in marine archaeology and the other in situation awareness simulation experiments. The impact of methods and HCI knowledge on the VR design process is analyzed, leading to proposals for presenting HCI and cognitive knowledge in the context of design trade-offs in the choice of VR design techniques. Problems reconciling VE and standard Graphical User Interface (GUI) design components are investigated. A trade-off framework for design options set against criteria for usability, efficient operation, realism, and presence is proposed. HCI-VR design advice and proposals for further research aimed towards improving human factor-related design in VEs are discussed.

Studying Children’s Navigation in Virtual Reality

Navigation in large-scale virtual environments is composed of locomotion and wayfinding. We compared two locomotion techniques in an immersive CAVE-like display in order to determine which one promotes better performance in children in a wayfinding task. A ‘treasure hunt’ game scenario was devised in which participants had to navigate to various houses of a virtual village that was previously seen only on a map. The 2D coordinates of paths taken by participants were recorded together with their success rates in finding the targets, and the time taken to reach their destination. Children showed that although the pointing method allowed them better control in locomotion, neither method was preferred in terms of success rates and timing.

A Social Creativity Support Tool Enhanced by Recommendation Algorithms: The Case of Software Architecture Design

Reusability of existing knowledge for the design and development of new ideas is a key principle of the definition of creativity as a process. Professionals to create the Architecture design of innovative software tools use software Architecture Design as such process. This work proposes a framework/tool by which the design of SAD can be directed based on several types of recommendations and in particular of well-known design patterns [1]. This work approaches the recommendations the use of contextual factors in combination with recommendation methods and known recommendation algorithms.