The Proof-of-Work algorithm that underlies Bitcoin, Ethereum w , 1 and many other cryptocurrencies is well known for its energy-intensive requirements. The Proof-of-Stake algorithm that underlies Ethereum and various other cryptocurrencies is less impactful environmentally, but it has a second, looming issue: the problem of wealth inequality. We have developed an alternative to Proof-of-Work and Proof-of-Stake, called Proof-by-Location, that has the potential to address both of these issues. This article describes Proof-by-Location and a financial platform called Xylem that is based on it. This platform seeks to distribute transaction fees to billions of cryptocurrency “Notaries” around the world (essentially, anyone with a smartphone), who work together to establish a distributed consensus about financial transactions. In this article, we demonstrate that this platform can scale to more than 3.9 trillion transactions per year (more than triple the number of digital payments per year currently occurring). We show a reduction of electricity usage per transaction of 99.9999914% compared to Bitcoin, 99.999905% compared to Ethereum w , 99.83% compared to Ethereum, and 95.9% compared to the Visa financial services company. We demonstrate that this platform would have a redistributive rather than consolidatory effect on wealth compared to any of these platforms, leading to a source of income for more than 1 billion people around the world, including more than 110 million in the bottom 10th to 20th percentile by income, with income for that group equivalent to 8.8 million full-time jobs. Finally, this currency provides a positive, non-compulsory mechanism for shaping human habitation patterns in ways that can slow global biodiversity loss and enable ecological restoration. Using Xylem as a global financial infrastructure could lead to significantly better social and environmental outcomes than existing financial platforms. 2

Network Analysis has traditionally been applied to analyzing interactions among learners in online learning platforms such as discussion boards. However, there are opportunities to bring Network Analysis to bear on networks representing learners' mental models of course material, rather than learner interactions. This paper describes the construction and analysis of collaborative educational networks based on concept maps created by undergraduates. Concept mapping activities were deployed throughout two separate quarters of a large General Education (GE) course about sustainability and technology at a large university on the West Coast of the United States. A variety of Network Analysis metrics are evaluated on their ability to predict an individual learner's understanding based on that learner's contributions to a network representing the collective understanding of all learners in the course. Several of the metrics significantly correlated with learner performance, especially those that compare an individual learner's conformity to the larger group's consensus. The novel network metrics based on collective networks of learner concept maps are shown to produce stronger and more reproducible correlations with learner performance than metrics traditionally used in the literature to evaluate concept maps. This paper thus demonstrates that Network Analysis in conjunction with collective networks of concept maps can provide insights into learners' conceptual understanding of course material.

Interactive computing systems increasingly allow for experimental evaluations of fundamental issues in law, government, and society. In this paper, we describe a participatory simulation of the Accountable Capitalism Act, a bill proposed in 2018 by US Senator Elizabeth Warren. We present findings from an empirical study conducted using this system, relating to the impact of 1) interactive visualization and 2) the Accountable Capitalism Act legal framework on the behavior of participants acting as corporate directors. From this study, we draw lessons about research possibilities at the juncture of HCI and legal and policy studies. This study contributes an analysis and evaluation of a design probe used to investigate potential impacts of the Accountable Capitalism Act, experimental evidence from a study conducted using the design probe, and guidance for future participatory simulations that seek to inform the design of social institutions.

Information system designers embed values into the systems they design, even if unwittingly. However, the values embedded in many information systems clash with values held by many sustainability communities. This research focuses on two grassroots sustainable agriculture communities, which are seeking to develop a food infrastructure that is under their own control, and thereby more resilient to disruptions across the globe. This paper presents a five-year ethnographic study of these two communities, maps out the values of members of these communities, and explores the implications of their values on the information systems that members use and that could be developed to support them in the future. By doing so, we hope to influence the design of future information systems to align more closely with the values of these stakeholders, and through these stakeholders to move toward a food system that supports food security and global sustainability.

What happens if efforts to achieve sustainability fail? Research in many fields argues that contemporary global industrial civilization will not persist indefinitely in its current form, and may, like many past human societies, eventually collapse. Arguments in environmental studies, anthropology, and other fields indicate that this transformation could begin within the next half-century. While imminent collapse is far from certain, it is prudent to consider now how to develop sociotechnical systems for use in these scenarios. We introduce the notion of collapse informatics—the study, design, and development of sociotechnical systems in the abundant present for use in a future of scarcity. We sketch the design space of collapse informatics and a variety of example projects. We ask how notions of practice—theorized as collective activity in the “here and now”—can shift to the future since collapse has yet to occur.

Research in many fields argues that contemporary global industrial civilization will not persist indefinitely in its current form, and may, like many past human societies, eventually collapse. Arguments in environmental studies, anthropology, and other fields indicate that this transformation could begin within the next half-century. While imminent collapse is far from certain, it is prudent to consider now how to develop sociotechnical systems for use in these scenarios. We introduce the notion of collapse informatics---the study, design, and development of sociotechnical systems in the abundant present for use in a future of scarcity---as a complement to ICT4D and mitigation-oriented sustainable HCI. We draw on a variety of literatures to offer a set of relevant concepts and articulate the relationships among them to orient and evaluate collapse informatics work. Observing that collapse informatics poses a unique class of cross-cultural design problems, we sketch the design space of collapse informatics and provide a variety of example projects. We explore points of connection and distinction between collapse informatics and sustainable HCI, ICT4D, and crisis informatics. Finally, we discuss next steps and comment on the potential value of collapse informatics work even in the event that collapse never occurs.

The field of HCI is growing, not only in the variety of application areas or the volume of research conducted, but also in the number of analytical approaches for use in the evaluation and design of interactive systems. However, despite the abundance of theoretical frameworks available, relatively little work has directly compared the application of these frameworks. This paper compares video analysis methods based on two analytic frameworks - activity theory (AT) and distributed cognition (DCog) - by performing an analysis of the same system from each of the two different theoretical perspectives. The results presented here provide a better understanding of how such theoretically informed methods in practice both resemble and differ from one another. Furthermore, this comparison enables specific insights about each of the theories themselves, as well as more general discussion about the role of theory in HCI.

Current software engineering practices have significant effects on the environment. Examples include e-waste from computers made obsolete due to software upgrades, and changes in the power demands of new versions of software. Sustainable software engineering aims to create reliable, long-lasting software that meets the needs of users while reducing environmental impacts. We conducted three related research efforts to explore this area. First, we investigated the extent to which users thought about the environmental impact of their software usage. Second, we created a tool called GreenTracker, which measures the energy consumption of software in order to raise awareness about the environmental impact of software usage. Finally, we explored the indirect environmental effects of software in order to understand how software affects sustainability beyond its own power consumption. The relationship between environmental sustainability and software engineering is complex; understanding both direct and indirect effects is critical to helping humans live more sustainably.

A significant amount of research has focused on blogs, bloggers, and blogging. However, relatively little work has examined blog readers, their interactions with bloggers, or their impact on blogging. This paper presents a qualitative study focusing specifically on readers of political blogs to develop a better understanding of readers’ interactions with blogs and bloggers. This is the first such study to examine the same blogging activity from both readers’ and bloggers’ perspectives. Readers’ significance and contributions to blogs are examined through a number of themes, including: community membership and participation; the relationship between political ideology, reading habits, and political participation; and differences and similarities between mainstream media (MSM) and blogs. Based on these analyses, this paper argues that blogging is not only a social activity, but is a collaborative process of co-creation in which both bloggers and readers engage. Implications of this finding contribute to the study and understanding of reader participation, to the design of technologies for bloggers and blog readers, and to the development of theoretical understandings of social media.

Blogs are becoming an increasingly important medium -- socially, academically, and politically. Much research has involved analyzing blogs, but less work has considered how such analytic techniques might be incorporated into tools for blog readers. A new tool, metaViz, analyzes political blogs for potential conceptual metaphors and presents them to blog readers. This paper presents a study exploring the types of critical and creative thinking fostered by metaViz as evidenced by user comments and discussion on the system. These results indicate the effectiveness of various system features at fostering critical thinking and creativity, specifically in terms of deep, structural reasoning about metaphors and creatively extending existing metaphors. Furthermore, the results carry broader implications beyond blogs and politics about exploring alternate configurations between computation and human thought.

Metaphor is often seen as a mode of creative thinking or as a means of fostering creativity. However, little work has studied creative generation of novel metaphors. This paper explores the use of computational metaphor identification (CMI) to foster creative generation of novel metaphors. CMI is a technique for analyzing textual corpora to identify potential conceptual metaphors. Drawing those metaphors to readers' attention can provide an opportunity to consider alternatives to current metaphors. This paper describes results from a study using CMI to foster metaphorical creativity in the context of science education. The results show that CMI leads to more creative mappings within metaphors. The key contributions of this paper are a demonstration that CMI can be used to foster more original metaphorical reasoning, and, more generally, implications for the study of metaphorical creativity.

Within the last decade, blogs have become an important element of popular culture, mass media, and the daily lives of countless Internet users. Despite the medium's interactive nature, most research on blogs focuses on either the blog itself or the blogger, rarely if at all focusing on the reader's impact. In order to gain a better understanding of the social practice of blogging, we must take into account the role, contributions, and significance of the reader. This paper presents the findings of a qualitative study of blog readers, including common blog reading practices, some of the dimensions along which reading practices vary, relationships between identity presentation and perception, the interpretation of temporality, and the ways in which readers feel that they are a part of the blogs they read. It also describes similarities to, and discrepancies with, previous work, and suggests a number of directions and implications for future work on blogging.

The ability to learn is a potentially compelling and important quality for interactive synthetic characters. To that end, we describe a practical approach to real-time learning for synthetic characters. Our implementation is grounded in the techniques of reinforcement learning and informed by insights from animal training. It simplifies the learning task for characters by (a) enabling them to take advantage of predictable regularities in their world, (b) allowing them to make maximal use of any supervisory signals, and (c) making them easy to train by humans.We built an autonomous animated dog that can be trained with a technique used to train real dogs called "clicker training". Capabilities demonstrated include being trained to recognize and use acoustic patterns as cues for actions, as well as to synthesize new actions from novel paths through its motion space.A key contribution of this paper is to demonstrate that by addressing the three problems of state, action, and state-action space discovery at the same time, the solution for each becomes easier. Finally, we articulate heuristics and design principles that make learning practical for synthetic characters.

This paper presents ways of approaching the design of successful character-based interactive installations. We rationalize our arguments within the context of both Disney's "illusion of life" and Daniel Dennett's "intentional stance". We present six perspectives from which intentional characters can be viewed: as interactors on a variety of time scales; as reciprocal interactors with each other, as entities exhibiting a dynamic expressive range, as creatures with life cycles; as a combination of allusions to existing media, and as a collection of well-balanced components. By conceptualizing characters in these ways, creators can generate installations that enable participants to read the desires, beliefs, and actions of the characters. This approach forms the basis of a successful character-based interactive installation.