Acquiring user information needs for recommender systems

Most recommender systems attempt to use collaborative filtering, content-based filtering or hybrid approach to recommend items to new users. Collaborative filtering recommends items to new users based on their similar neighbours, and content-based filtering approach tries to recommend items that are similar to new users' profiles. The fundamental issues include how to profile new users, and how to deal with the over-specialization in content-based recommender systems. Indeed, the terms used to describe items can be formed as a concept hierarchy. Therefore, we aim to describe user profiles or information needs by using concepts vectors. This paper presents a new method to acquire user information needs, which allows new users to describe their preferences on a concept hierarchy rather than rating items. It also develops a new ranking function to recommend items to new users based on their information needs. The proposed approach is evaluated on Amazon book datasets. The experimental results demonstrate that the proposed approach can largely improve the effectiveness of recommender systems.

Tensor reduction for user profiling in personalized recommender systems

User profiling is the process of constructing user models which represent personal characteristics and preferences of customers. User profiles play a central role in many recommender systems. Recommender systems recommend items to users based on user profiles, in which the items can be any objects which the users are interested in, such as documents, web pages, books, movies, etc. In recent years, multidimensional data are getting more and more attention for creating better recommender systems from both academia and industry. Additional metadata provides algorithms with more details for better understanding the interactions between users and items. However, most of the existing user/item profiling techniques for multidimensional data analyze data through splitting the multidimensional relations, which causes information loss of the multidimensionality. In this paper, we propose a user profiling approach using a tensor reduction algorithm, which we will show is based on a Tucker2 model. The proposed profiling approach incorporates latent interactions between all dimensions into user profiles, which significantly benefits the quality of neighborhood formation. We further propose to integrate the profiling approach into neighborhoodbased collaborative filtering recommender algorithms. Experimental results show significant improvements in terms of recommendation accuracy.

Using smartphones for cycling safety: A survey of riders preferences and interest in new technologies

Cyclists are among the most vulnerable road users. Many recent interventions have aimed at improving their safety on the road, such as the minimum overtaking distance rule introduced in Queensland in 2014. Smartphones offer excellent opportunities for technical intervention for road safety at a limited cost. Indeed, they have a lot of available processing power and many embedded sensors that allow analysing a rider's (or driver's) motion, behaviour, and environment; this is especially relevant for cyclists, as they do not have the space or power allowance that can be found in most motor vehicles. The aim of the study presented in this paper is to assess cyclists’ support for a range of new smartphone-based safety technologies. The preliminary results for an online survey with cyclists recruited from Bicycle Queensland and Triathlon Queensland, with N=191, are presented. A number of innovative safety systems such as automatic logging of incidents without injuries, reporting of dangerous area via a website/app, automatic notification of emergency services in case of crash or fall, and advanced navigation apps were assessed. A significant part of the survey is dedicated to GoSafeCycle, a cooperative collision prevention app based on motion tracking and Wi-Fi communications developed at CARRS-Q. Results show a marked preference toward automatic detection and notification of emergencies (62-70% positive assessment) and GoSafeCycle (61.7% positive assessment), as well as reporting apps (59.1% positive assessment). Such findings are important in the context of current promotion of active transports and highlight the need for further development of system supported by the general public.

Methodology to obtain the user's Human Values Scale from Smart User Models

En años recientes,la Inteligencia Artificial ha contribuido a resolver problemas encontrados en el desempeño de las tareas de unidades informáticas, tanto si las computadoras están distribuidas para interactuar entre ellas o en cualquier entorno (Inteligencia Artificial Distribuida). Las Tecnologías de la Información permiten la creación de soluciones novedosas para problemas específicos mediante la aplicación de los hallazgos en diversas áreas de investigación. Nuestro trabajo está dirigido a la creación de modelos de usuario mediante un enfoque multidisciplinario en los cuales se emplean los principios de la psicología, inteligencia artificial distribuida, y el aprendizaje automático para crear modelos de usuario en entornos abiertos; uno de estos es la Inteligencia Ambiental basada en Modelos de Usuario con funciones de aprendizaje incremental y distribuido (conocidos como Smart User Model). Basándonos en estos modelos de usuario, dirigimos esta investigación a la adquisición de características del usuario importantes y que determinan la escala de valores dominantes de este en aquellos temas en los cuales está más interesado, desarrollando una metodología para obtener la Escala de Valores Humanos del usuario con respecto a sus características objetivas, subjetivas y emocionales (particularmente en Sistemas de Recomendación).Una de las áreas que ha sido poco investigada es la inclusión de la escala de valores humanos en los sistemas de información. Un Sistema de Recomendación, Modelo de usuario o Sistemas de Información, solo toman en cuenta las preferencias y emociones del usuario [Velásquez, 1996, 1997; Goldspink, 2000; Conte and Paolucci, 2001; Urban and Schmidt, 2001; Dal Forno and Merlone, 2001, 2002; Berkovsky et al., 2007c]. Por lo tanto, el principal enfoque de nuestra investigación está basado en la creación de una metodología que permita la generación de una escala de valores humanos para el usuario desde el modelo de usuario. Presentamos resultados obtenidos de un estudio de casos utilizando las características objetivas, subjetivas y emocionales en las áreas de servicios bancarios y de restaurantes donde la metodología propuesta en esta investigación fue puesta a prueba.En esta tesis, las principales contribuciones son: El desarrollo de una metodología que, dado un modelo de usuario con atributos objetivos, subjetivos y emocionales, se obtenga la Escala de Valores Humanos del usuario. La metodología propuesta está basada en el uso de aplicaciones ya existentes, donde todas las conexiones entre usuarios, agentes y dominios que se caracterizan por estas particularidades y atributos; por lo tanto, no se requiere de un esfuerzo extra por parte del usuario.

A web 2.0 user interface for wide-area resource monitoring

Resource monitoring in distributed systems is required to understand the 'health' of the overall system and to help identify particular problems, such as dysfunctional hardware or faulty system or application software. Monitoring systems such as GridRM provide the ability to connect to any number of different types of monitoring agents and provide different views of the system, based on a client's particular preferences. Web 2.0 technologies, and in particular 'mashups', are emerging as a promising technique for rapidly constructing rich user interfaces, that combine and present data in intuitive ways. This paper describes a Web 2.0 user interface that was created to expose resource data harvested by the GridRM resource monitoring system.

An ontological modelling of user requirements for personalised information provision

The knowledge economy offers opportunity to a broad and diverse community of information systems users to efficiently gain information and know-how for improving qualifications and enhancing productivity in the work place. Such demand will continue and users will frequently require optimised and personalised information content. The advancement of information technology and the wide dissemination of information endorse individual users when constructing new knowledge from their experience in the real-world context. However, a design of personalised information provision is challenging because users’ requirements and information provision specifications are complex in their representation. The existing methods are not able to effectively support this analysis process. This paper presents a mechanism which can holistically facilitate customisation of information provision based on individual users’ goals, level of knowledge and cognitive styles preferences. An ontology model with embedded norms represents the domain knowledge of information provision in a specific context where users’ needs can be articulated and represented in a user profile. These formal requirements can then be transformed onto information provision specifications which are used to discover suitable information content from repositories and pedagogically organise the selected content to meet the users’ needs. The method is provided with adaptability which enables an appropriate response to changes in users’ requirements during the process of acquiring knowledge and skills.

Reasoning with incomplete and imprecise preferences

Preferences are present in many real life situations but it is often difficult to quantify them giving a precise value. Sometimes preference values may be missing because of privacy reasons or because they are expensive to obtain or to produce. In some other situations the user of an automated system may have a vague idea of whats he wants. In this thesis we considered the general formalism of soft constraints, where preferences play a crucial role and we extended such a framework to handle both incomplete and imprecise preferences. In particular we provided new theoretical frameworks to handle such kinds of preferences. By admitting missing or imprecise preferences, solving a soft constraint problem becomes a different task. In fact, the new goal is to find solutions which are the best ones independently of the precise value the each preference may have. With this in mind we defined two notions of optimality: the possibly optimal solutions and the necessary optimal solutions, which are optimal no matter we assign a precise value to a missing or imprecise preference. We provided several algorithms, bases on both systematic and local search approaches, to find such kind of solutions. Moreover, we also studied the impact of our techniques also in a specific class of problems (the stable marriage problems) where imprecision and incompleteness have a specific meaning and up to now have been tackled with different techniques. In the context of the classical stable marriage problem we developed a fair method to randomly generate stable marriages of a given problem instance. Furthermore, we adapted our techniques to solve stable marriage problems with ties and incomplete lists, which are known to be NP-hard, obtaining good results both in terms of size of the returned marriage and in terms of steps need to find a solution.

Exploring users inter-temporal preferences for measuring transport social equity effects

There exist different ways for defining a welfare function. Traditionally, welfare economic theory foundation is based on the Net Present Value (NPV) calculation where the time dependent preferences of considered agents are taken into account. However, the time preferences, remains a controversial subject. Currently, the traditional approach employs a unique discount rate for various agents. Nevertheless, this way of discounting appears inconsistent with sustainable development. New research work suggests that the discount rate may not be a homogeneous value. The discount rates may change following the individual’s preferences. A significant body of evidence suggests that people do not behave following a constant discount rate. In fact, UK Government has quickly recognized the power of the arguments for time-varying rates, as it has done in its official guidance to Ministries on the appraisal of investments and policies. Other authors deal with not just time preference but with uncertainty about future income (precautionary saving). In a situation in which economic growth rates are similar across time periods, the rationale for declining social optimal discount rates is driven by the preferences of the individuals in the economy, rather than expectations of growth. However, these approaches have been mainly focused on long-term policies where intergenerational risks may appear. The traditional cost-benefit analysis (CBA) uses a unique discount rate derived from market interest rates or investment rates of return for discounting the costs and benefits of all social agents included in the CBA. However, recent literature showed that a more adequate measure of social benefit is possible by using different discount rates including inter-temporal preferences rate of users, private investment discount rate and intertemporal preferences rate of government. Actually, the costs of opportunity may differ amongst individuals, firms, governments, or society in general, as do the returns on savings. In general, the firms or operators require an investment rate linked to the current return on savings, while the discount rate of consumers-users depends on their time preferences with respect of the current and the future consumption, as well as society can take into account the intergenerational well-being, adopting a lower discount rate for today’s generation. Time discount rate of social actors (users, operators, government and society) places a lower value in a future gain, but the uncertainty about future income strongly determines the individual preferences. These time and uncertainty depends on preferences and should be integrated into a transport policy formulation that may have significant social impacts. The discount rate of a user cannot be the same than the operator’s discount rate. The preferences of both are different. In addition, another school of thought suggests that people, such as a social group, may have different attitudes towards future costs and benefits. Particularly, the users have different discount rates related to their income. Some research work tried to modify user discount rates using a compensating weight which represents the inverse of household income level. The inter-temporal preferences are a proxy of the willingness to pay during the time. Its consideration is important in order to make acceptable or not a policy or investment

User experience with immersive and interactive media = Experiencia de usuario en entornos 3D inmersivos e interactivos

Estudios recientes promueven la integración de estímulos multisensoriales en activos multimedia con el fin de mejorar la experiencia de usuario mediante la estimulación de nuevos sentidos, más allá de la tradicional experiencia audiovisual. Del mismo modo, varios trabajos proponen la introducción de componentes de interacción capaces de complementar con nuevas características, funcionalidades y/o información la experiencia multimedia. Efectos sensoriales basados en el uso de nuevas técnicas de audio, olores, viento, vibraciones y control de la iluminación, han demostrado tener un impacto favorable en la sensación de Presencia, en el disfrute de la experiencia multimedia y en la calidad, relevancia y realismo de la misma percibidos por el usuario. Asimismo, los servicios basados en dos pantallas y la manipulación directa de (elementos en) la escena de video tienen el potencial de mejorar la comprensión, la concentración y la implicación proactiva del usuario en la experiencia multimedia. El deporte se encuentra entre los géneros con mayor potencial para integrar y explotar éstas soluciones tecnológicas. Trabajos previos han demostrado asimismo la viabilidad técnica de integrar éstas tecnologías con los estándares actualmente adoptados a lo largo de toda la cadena de transmisión de televisión. De este modo, los sistemas multimedia enriquecidos con efectos sensoriales, los servicios interactivos multiplataforma y un mayor control del usuario sobre la escena de vídeo emergen como nuevas formas de llevar la multimedia immersiva e interactiva al mercado de consumo de forma no disruptiva. Sin embargo, existen numerosas interrogantes relativas a los efectos sensoriales y/o soluciones interactivas más adecuadas para complementar un contenido audiovisual determinado o a la mejor manera de de integrar y combinar dichos componentes para mejorar la experiencia de usuario de un segmento de audiencia objetivo. Además, la evidencia científica sobre el impacto de factores humanos en la experiencia de usuario con estas nuevas formas de immersión e interacción en el contexto multimedia es aún insuficiente y en ocasiones, contradictoria. Así, el papel de éstos factores en el potencial de adopción de éstas tecnologías ha sido amplia-mente ignorado. La presente tesis analiza el impacto del audio binaural, efectos sensoriales (de iluminación y olfativos), interacción con objetos 3D integrados en la escena de vídeo e interacción con contenido adicional utilizando una segunda pantalla en la experiencia de usuario con contenidos de deporte. La posible influencia de dichos componentes en las variables dependientes se explora tanto a nivel global (efecto promedio) como en función de las características de los usuarios (efectos heterogéneos). Para ello, se ha llevado a cabo un experimento con usuarios orientado a explorar la influencia de éstos componentes immersivos e interactivos en dos grandes dimensiones de la experiencia multimedia: calidad y Presencia. La calidad de la experiencia multimedia se analiza en términos de las posibles variaciones asociadas a la calidad global y a la calidad del contenido, la imagen, el audio, los efectos sensoriales, la interacción con objetos 3D y la interacción con la segunda pantalla. El posible impacto en la Presencia considera dos de las dimensiones definidas por el cuestionario ITC-SOPI: Presencia Espacial (Spatial Presence) e Implicación (Engagement). Por último, los individuos son caracterizados teniendo en cuenta los siguientes atributos afectivos, cognitivos y conductuales: preferencias y hábitos en relación con el contenido, grado de conocimiento de las tecnologías integradas en el sistema, tendencia a involucrarse emocionalmente, tendencia a concentrarse en una actividad bloqueando estímulos externos y los cinco grandes rasgos de la personalidad: extroversión, amabilidad, responsabilidad, inestabilidad emocional y apertura a nuevas experiencias. A nivel global, nuestro estudio revela que los participantes prefieren el audio binaural frente al sistema estéreo y que los efectos sensoriales generan un aumento significativo del nivel de Presencia Espacial percibido por los usuarios. Además, las manipulaciones experimentales realizadas permitieron identificar una gran variedad de efectos heterogéneos. Un resultado interesante es que dichos efectos no se encuentran distribuidos de forma equitativa entre las medidas de calidad y Presencia. Nuestros datos revelan un impacto generalizado del audio binaural en la mayoría de las medidas de calidad y Presencia analizadas. En cambio, la influencia de los efectos sensoriales y de la interacción con la segunda pantalla se concentran en las medidas de Presencia y calidad, respectivamente. La magnitud de los efectos heterogéneos identificados está modulada por las siguientes características personales: preferencias en relación con el contenido, frecuencia con la que el usuario suele ver contenido similar, conocimiento de las tecnologías integradas en el demostrador, sexo, tendencia a involucrarse emocionalmente, tendencia a a concentrarse en una actividad bloqueando estímulos externos y niveles de amabilidad, responsabilidad y apertura a nuevas experiencias. Las características personales consideradas en nuestro experimento explicaron la mayor parte de la variación en las variables dependientes, confirmando así el importante (y frecuentemente ignorado) papel de las diferencias individuales en la experiencia multimedia. Entre las características de los usuarios con un impacto más generalizado se encuentran las preferencias en relación con el contenido, el grado de conocimiento de las tecnologías integradas en el sistema y la tendencia a involucrarse emocionalmente. En particular, los primeros dos factores parecen generar un conflicto de atención hacia el contenido versus las características/elementos técnicos del sistema, respectivamente. Asimismo, la experiencia multimedia de los fans del fútbol parece estar modulada por procesos emociona-les, mientras que para los no-fans predominan los procesos cognitivos, en particular aquellos directamente relacionados con la percepción de calidad. Abstract Recent studies encourage the integration of multi-sensorial stimuli into multimedia assets to enhance the user experience by stimulating other senses beyond sight and hearing. Similarly, the introduction of multi-modal interaction components complementing with new features, functionalities and/or information the multimedia experience is promoted. Sensory effects as odor, wind, vibration and light effects, as well as an enhanced audio quality, have been found to favour media enjoyment and to have a positive influence on the sense of Presence and on the perceived quality, relevance and reality of a multimedia experience. Two-screen services and a direct manipulation of (elements in) the video scene have the potential to enhance user comprehension, engagement and proactive involvement of/in the media experience. Sports is among the genres that could benefit the most from these solutions. Previous works have demonstrated the technical feasibility of implementing and deploying end-to-end solutions integrating these technologies into legacy systems. Thus, sensorially-enhanced media, two-screen services and an increased user control over the displayed scene emerge as means to deliver a new form of immersive and interactive media experiences to the mass market in a non-disruptive manner. However, many questions remain concerning issues as the specific interactive solutions or sensory effects that can better complement a given audiovisual content or the best way in which to integrate and combine them to enhance the user experience of a target audience segment. Furthermore, scientific evidence on the impact of human factors on the user experience with these new forms of immersive and interactive media is still insufficient and sometimes, contradictory. Thus, the role of these factors on the potential adoption of these technologies has been widely ignored. This thesis analyzes the impact of binaural audio, sensory (light and olfactory) effects, interaction with 3D objects integrated into the video scene and interaction with additional content using a second screen on the sports media experience. The potential influence of these components on the dependent variables is explored both at the overall level (average effect) and as a function of users’ characteristics (heterogeneous effects). To these aims, we conducted an experimental study exploring the influence of these immersive and interactive elements on the quality and Presence dimensions of the media experience. Along the quality dimension, we look for possible variations on the quality scores as-signed to the overall media experience and to the media components content, image, audio, sensory effects, interaction with 3D objects and interaction using the tablet device. The potential impact on Presence is analyzed by looking at two of the four dimensions defined by the ITC-SOPI questionnaire, namely Spatial Presence and Engagement. The users’ characteristics considered encompass the following personal affective, cognitive and behavioral attributes: preferences and habits in relation to the content, knowledge of the involved technologies, tendency to get emotionally involved and tendency to get absorbed in an activity and block out external distractors and the big five personality traits extraversion, agreeableness, conscientiousness, neuroticism and openness to experience. At the overall level, we found that participants preferred binaural audio than standard stereo audio and that sensory effects increase significantly the level of Spatial Presence. Several heterogeneous effects were also revealed as a result of our experimental manipulations. Interestingly, these effects were not equally distributed across the quality and Presence measures analyzed. Whereas binaural audio was foud to have an influence on the majority of the quality and Presence measures considered, the effects of sensory effects and of interaction with additional content through the tablet device concentrate mainly on the dimensions of Presence and on quality measures, respectively. The magnitude of these effects was modulated by individual’s characteristics, such as: preferences in relation to the content, frequency of viewing similar content, knowledge of involved technologies, gender, tendency to get emotionally involved, tendency to absorption and levels of agreeableness, conscientiousness and openness to experience. The personal characteristics collected in our experiment explained most of the variation in the dependent variables, confirming the frequently neglected role of individual differences on the media experience. Preferences in relation to the content, knowledge of involved technologies and tendency to get emotionally involved were among the user variables with the most generalized influence. In particular, the former two features seem to present a conflict in the allocation of attentional resources towards the media content versus the technical features of the system, respectively. Additionally, football fans’ experience seems to be modulated by emotional processes whereas for not fans, cognitive processes (and in particular those related to quality judgment) prevail.

Using context and preferences to implement self-adapting pervasive computing applications

Applications that exploit contextual information in order to adapt their behaviour to dynamically changing operating environments and user requirements are increasingly being explored as part of the vision of pervasive or ubiquitous computing. Despite recent advances in infrastructure to support these applications through the acquisition, interpretation and dissemination of context data from sensors, they remain prohibitively difficult to develop and have made little penetration beyond the laboratory. This situation persists largely due to a lack of appropriately high-level abstractions for describing, reasoning about and exploiting context information as a basis for adaptation. In this paper, we present our efforts to address this challenge, focusing on our novel approach involving the use of preference information as a basis for making flexible adaptation decisions. We also discuss our experiences in applying our conceptual and software frameworks for context and preference modelling to a case study involving the development of an adaptive communication application.

Website physical activity interventions: preferences of potential users

Information and communication technologies (particularly websites and e-mail) have the potential to deliver health behavior change programs to large numbers of adults at low cost. Controlled trials using these new media to promote physical activity have produced mixed results. User-centered development methods can assist in understanding the preferences of potential participants for website functions and content, and may lead to more effective programs. Eight focus group discussions were conducted with 40 adults after they had accessed a previously trialed physical activity website. The discussions were audio taped, transcribed and interpreted using a themed analysis method. Four key themes emerged: structure, interactivity, environmental context and content. Preferences were expressed for websites that include simple interactive features, together with information on local community activity opportunities. Particular suggestions included online community notice boards, personalized progress charts, e-mail access to expert advice and access to information on specific local physical activity facilities and services. Website physical activity interventions could usefully include personally relevant interactive and environmentally focused features and services identified through a user-centered development process.

Designing for User-facing Uncertainty in Everyday Sensing and Prediction

Thesis (Ph.D.)--University of Washington, 2016-07

Evidence that risk adjustment is unnecessary in estimates of the User cost of money

Investors value the special attributes of monetary assets (e.g., exchangeability, liquidity, and safety) and pay a premium for holding them in the form of a lower return rate -- The user cost of holding monetary assets can be measured approximately by the difference between the returns on illiquid risky assets and those of safer liquid assets -- A more appropriate measure should adjust this difference by the differential risk of the assets in question -- We investigate the impact that time non-separable preferences has on the estimation of the risk-adjusted user cost of money -- Using U.K. data from 1965Q1 to 2011Q1, we estimate a habit-based asset pricing model with money in the utility function and find that the risk adjustment for risky monetary assets is negligible -- Thus, researchers can dispense with risk adjusting the user cost of money in constructing monetary aggregate indexes

AN EMPIRICAL ASSESSMENT OF USER ONLINE SECURITY BEHAVIOR: EVIDENCE FROM A UNIVERSITY

The ever-increasing number and severity of cybersecurity breaches makes it vital to understand the factors that make organizations vulnerable. Since humans are considered the weakest link in the cybersecurity chain of an organization, this study evaluates users’ individual differences (demographic factors, risk-taking preferences, decision-making styles and personality traits) to understand online security behavior. This thesis studies four different yet tightly related online security behaviors that influence organizational cybersecurity: device securement, password generation, proactive awareness and updating. A survey (N=369) of students, faculty and staff in a large mid-Atlantic U.S. public university identifies individual characteristics that relate to online security behavior and characterizes the higher-risk individuals that pose threats to the university’s cybersecurity. Based on these findings and insights from interviews with phishing victims, the study concludes with recommendations to help similat organizations increase end-user cybersecurity compliance and mitigate the risks caused by humans in the organizational cybersecurity chain.