Human–Computer Collaboration for Visual Analytics: an Agent-based Framework

The visual analytics community has long aimed to understand users better and assist them in their analytic endeavors. As a result, numerous conceptual models of visual analytics aim to formalize common workflows, techniques, and goals leveraged by analysts. While many of the existing approaches are rich in detail, they each are specific to a particular aspect of the visual analytic process. Furthermore, with an ever-expanding array of novel artificial intelligence techniques and advances in visual analytic settings, existing conceptual models may not provide enough expressivity to bridge the two fields. In this work, we propose an agent-based conceptual model for the visual analytic process by drawing parallels from the artificial intelligence literature. We present three examples from the visual analytics literature as case studies and examine them in detail using our framework. Our simple yet robust framework unifies the visual analytic pipeline to enable researchers and practitioners to reason about scenarios that are becoming increasingly prominent in the field, namely mixed-initiative, guided, and collaborative analysis. Furthermore, it will allow us to characterize analysts, visual analytic settings, and guidance from the lenses of human agents, environments, and artificial agents, respectively.     

A relational perspective on the walking activity in urban spaces: Shaping,transformation, and interrelations

New walking studies have been concerned with the multiplicity of pedestrian experiences. Some consider walking as an activity that unfolds as part of social life, allowing people to create relationships with others, where multiple walking types can be identified depending on these relations. Some contributions, inspired by actor-network theory (ANT), suggest understanding this activity through a networked perspective that associates human and non-human actors, with a focus on their various and dynamic relations between them. The focus on stabilized networks, which emphasizes the recurrence of these relations, helps in identifying and extending themultiplicity of walking activity experience and emerging types. Despite this potential, ANT contributions are still limited. This paper aims to present the ANT potential in unpacking the multiplicity of the walking activity. It utilizes the case of Dahiyat Al Hussain park in Jordan and applies an ANT-inspired ethnographic approach to unpackwalking. It uses desk research, in-depth interviews, go-along interviews, and observations to engage with participants’ views and experiences. By tracing the recurring relational patterns, the paper identifies three instances when walking practice can be considered as stabilized during network shaping, transformation, and interrelations. These stabilizations provide a nuanced perspective into the multiplicity of walking practices.     

Effect of fading,diversity and interference on the performance of multitone CDMA systems

The performance of a multitone Code Division Multiple Access (CDMA) system is investigated in this paper by considering the effect of multipath fading, diversity and narrowband interference. The performance is evaluated in terms of the average bit error rate when both multiple access and partial band interference are present. Results are obtained by deriving the statistics of the receiver output parameters and then tested by numerical evaluation. The bit error rate performance is analyzed as a function of bit rate, bandwidth, delay range and different diversity techniques, while considering issues relevant to system implementation. Comparisons were made between conventional single‐tone CDMA systems and multitone CDMA systems. The effectiveness of multitone CDMA in suppressing interference compared to conventional CDMA system is analyzed. Results reveal considerable performance improvement of multitone CDMA system over conventional CDMA system. Copyright © 2002 John Wiley & Sons, Ltd.