We investigate the role of directed information in portfolio theory, data compression, and statistics with causality constraints. In particular, we show that directed information is an upper bound on ...the increment in growth rates of optimal portfolios in a stock market due to causal side information. This upper bound is tight for gambling in a horse race, which is an extreme case of stock markets. Directed information also characterizes the value of causal side information in instantaneous compression and quantifies the benefit of causal inference in joint compression of two stochastic processes. In hypothesis testing, directed information evaluates the best error exponent for testing whether a random process Y causally influences another process X or not. These results lead to a natural interpretation of directed information I ( Yn → Xn ) as the amount of information that a random sequence Yn = ( Y 1 , Y 2 ,..., Yn ) causally provides about another random sequence Xn = ( X 1 , X 2 ,..., Xn ). A new measure, directed lautum information, is also introduced and interpreted in portfolio theory, data compression, and hypothesis testing.
Bridge Builders National Research Council; Policy and Global Affairs; Office of International Affairs ...
01/2000
eBook
Open access
This volume tells 16 remarkable stories?first person accounts of how information and communication technologies have been successfully introduced into institutions for the benefit of scientists and ...engineers in sub-Saharan Africa. These case studies focus on the lessons learned in designing and implementing projects dealing with scientific and technological information and examine the impact.
•Blogger activities of 17 brands in Turkey were analyzed via in-depth interviews.•Results reveal that bloggers’ online authority make them a digital influencer.•Brand communication through digital ...influencers model is developed based on two-step flow communication theory.•Winning bloggers’ support and leveraging their endorsement enable brands to gain the influence necessary to spread messages virally.
The growing power of bloggers to influence their connected network has emerged as a new communication venue for brands. This study elaborates upon the role of bloggers in brand communication, and reveals how brands can engage with bloggers, currently considered as online opinion leaders, from the perspective of the two-step flow theory. Following clarification of the aims of the study, we report on in-depth interviews with 17 brand and digital agency representatives, selected because they regard communication with bloggers as an important strategy in increasing the influence of their brands among online communities. This exploratory study reflects current blogger communication implementations, and concludes with a discussion of seven major issues arising from the literature review and interviews (definition of bloggers, blogger selection criteria, digital integration, power of bloggers, long-term relationship building with bloggers, measurement, and budgetary issues in blogger communication). These areas represent relatively unexplored areas of blogger engagement from both an academic and managerial perspective. Based on the findings of the interviews, we propose a model which traces the influencer role of bloggers from the two-step flow theory perspective. This model is named as the brand communication through digital influencers model.
Personalized services are increasingly popular in the Internet world. This study identifies theories related to the use of personalized content services and their effect on user satisfaction. Three ...major theories have been identified-information overload, uses and gratifications, and user involvement. The information overload theory implies that user satisfaction increases when the recommended content fits user interests (i.e., the recommendation accuracy increases). The uses and gratifications theory indicates that motivations for information access affect user satisfaction. The user involvement theory implies that users prefer content recommended by a process in which they have explicit involvement. In this research, a research model was proposed to integrate these theories and two experiments were conducted to examine the theoretical relationships. Our findings indicate that information overload and uses and gratifications are two major theories for explaining user satisfaction with personalized services. Personalized services can reduce information overload and, hence, increase user satisfaction, but their effects may be moderated by the motivation for information access. The effect is stronger for users whose motivation is in searching for a specific target. This implies that content recommendation would be more useful for knowledge management systems, where users are often looking for specific knowledge, rather than for general purpose Web sites, whose customers often come for scanning. Explicit user involvement in the personalization process may affect a user's perception of customization, but has no significant effect on overall satisfaction.
Purpose
The purpose of this paper is to argue that scholars in the information behavior (IB) field should embrace the theoretical framework of the everyday to explore a more holistic view of IB.
...Design/methodology/approach
The paper describes the theory of the everyday and delineates four opportunities offered by scholars of the everyday. The paper concludes with three examples that highlight what a more everyday-focused everyday information behavior might look like.
Findings
The theory of the everyday provides a useful theoretical framework to ground research addressing the everyday world as well as useful concepts for analysis and research methodology.
Originality/value
The theoretical framework of the everyday contributes to IB research by providing a theoretical justification for work addressing everyday life as well as useful concepts for analysis. The paper also outlines the benefits of integrating methods influenced by institutional ethnography, a methodology previously used to address the nuances of the everyday world.
•Address the problem of low response rate in social Q&A that happens on a Chinese microblogging site.•Propose 17 factors from both the questioner and the question's perspectives and investigate their ...effectiveness in determine whether or not a question will be answered.•Build a model to differentiate questions with high probabilities of being responded from those with low probabilities of being answered, which achieved a prediction accuracy of 74%.•Our results show that whether or not a question will be answered depend more on the questioner than the question.•Propose the potential implication of improving visibility of users with low social capital to increase their question's response probability.
With the noted popularity of social networking sites, people increasingly rely on these social networks to address their information needs. Although social question and answering is potentially an important venue seeking information online, it, unfortunately, suffers from a problem of low response rate, with the majority of questions receiving no response. To understand why the response rate of social question and answering is low and hopefully to increase it in the future, this research analyzes extrinsic factors that may influence the response probability of questions posted on Sina Weibo. We propose 17 influential factors from 2 different perspectives: the content of the question, and the characteristics of the questioner. We also train a prediction model to forecast a question's likelihood of being responded based on the proposed features We test our predictive model on more than 60,000 real-world questions posted on Weibo, which generate more than 600,000 responses. Findings show that a Weibo's question answerability is primarily contingent on the questioner versus the question. Our findings indicate that using appreciation emojis can increase a question's response probability, whereas the use of hashtags negatively influences the chances of receiving answers. Our contribution is in providing insights for the design and development of future social question and answering tools, as well as for enhancing social network users’ collaboration in supporting social information seeking activities.
This book studies the intertwined processes of information systems implementation and organizational change within the current trend of economic globalization. It highlights the significance of local ...context and points out the institutional forces and the multiple rationalities that influence the implementation and use of information technology in diverse organizational settings.
•All six theoretical models have good explanatory power of behavioral intention (BI).•Based on variance explanation, the motivational model (MM) and the technology acceptance model (TAM) have ...stronger explanatory powers.•The theory of planned behavior (TPB) and the TAM have larger effect size compared to other theories.•Perceived usefulness (PU), attitude (ATT), cloud service quality (CSQ), perceived behavior control (PBC), result demonstration (RD), visibility (VIS), and cloud self-efficacy (CSE) are important factors of a unified model.
Cloud computing is an innovative information technology that has been applied to education and has facilitated the development of cloud computing classrooms; however, student behavioral intention (BI) toward cloud computing remains unclear. Most researchers have evaluated, integrated, or compared only few theories to examine user BI. In this study, we tested, compared, and unified six well-known theories, namely service quality (SQ), self-efficacy (SE), the motivational model (MM), the technology acceptance model (TAM), the theory of reasoned action or theory of planned behavior (TRA/TPB), and innovation diffusion theory (IDT), in the context of cloud computing classrooms. This empirical study was conducted using an online survey. The data collected from the samples (n=478) were analyzed using structural equation modeling. We independently analyzed each theory, by formulating a united model. The analysis yielded three valuable findings. First, all six theoretical models and the united model exhibited adequate explanatory power. Second, variance explanation, Chi-squared statistics, effect size, and predictive relevance results revealed the ranking importance of the theoretical models. Third, the united model provided a comprehensive understanding of the factors that significantly affect the college students’ BI toward a cloud computing classroom. The discussions and implications of this study are critical for researchers and practitioners.
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