Herding model and 1/f noise

We provide evidence that for some values of the parameters a simple agent based model, describing herding behavior, yields signals with 1/f power spectral density. We derive a non-linear stochastic differential equation for the ratio of number of agents and show, that it has the form proposed earlier for modeling of 1/f^beta noise with different exponents beta. The non-linear terms in the transition probabilities, quantifying the herding behavior, are crucial to the appearance of 1/f noise. Thus, the herding dynamics can be seen as a microscopic explanation of the proposed non-linear stochastic differential equations generating signals with 1/f^beta spectrum. We also consider the possible feedback of macroscopic state on microscopic transition probabilities strengthening the non-linearity of equations and providing more opportunities in the modeling of processes exhibiting power-law statistics

Derivation of a No-significant-risk-level (NSRL) for dermal exposures to diethanolamine

AbstractDiethanolamine (DEA) has been found to produce liver and kidney tumors in mice following lifetime dermal exposures. Data regarding the mode of action by which DEA produces these tumors were used to support a dose-response assessment that resulted in a no-significant-risk-level (NSRL) for dermal exposures to DEA. DEA and its metabolites are structural analogs to endogenous agents important to choline homeostasis. Sufficient information is available to support an epigenetic MOA involving the perturbation of choline homeostasis and hepatic methylation reactions in the formation of mouse liver tumors. This MOA may also apply to mouse kidney tumors, but direct measurements for key events in kidney are lacking. For both tumor types, dose-response data were pooled across four cancer bioassays conducted for DEA and DEA-containing condensates in order to provide a more robust characterization of the dose-response relationships. Doses were expressed in terms of dermally absorbed dose so that the dose-dependency and species differences in the dermal absorption of DEA were addressed. The resulting NSRL value of 3400 ug/day for dermal exposures to DEA is considered to be protective of human health for both tumor endpoints

BOLLOCKS!! Designing pervasive games that play with the social rules of built environments

We propose that pervasive games designed with mechanics that are specifically in opposition with, or disruptive of, social rules of the environment in which they are played, have unique potential to provide interesting, provocative experiences for players. We explore this concept through the design and evaluation of an experimental game prototype, Shhh!, inspired by the juvenile game Bollocks, and implemented on Android mobile devices, which challenges players to make loud noises in libraries. Six participants played the game before engaging in semi-structured interviews, explored through inductive thematic analysis. Results suggest that the game provoked in players a heightened awareness of social rules, as well as a complex social dilemma of whether or not to act. We conclude by presenting a model for designing games that play with the social, as well as physical, rules of the environments in which they are set

Exploring Twitter as a game platform; strategies and opportunities for microblogging-based games

Recent years have seen the massive daily engagement of players with games that are integrated with online social networking sites, such as Facebook. However, few games have successfully created engaging experiences through integration with microblogging websites. In this paper, we explore the opportunities and challenges in using Twitter as a platform for playing games, through the case study of the game Hashtag Dungeon, a dungeon-crawling game that uses Twitter for collaborative creation of game content. Two studies were carried out. A quantitative user study with 32 participants demonstrated that players found the game engaging and rewarding. A follow-up qualitative study with 8 participants suggests that Twitter integration in this game is meaningful, but that there are concerns over the impact of the game on players’ Twitter profiles. Based on findings from both studies, we propose strategies for the design of Microblogging-based games, and discuss wider implications of social media integration in games

Formation of Common Investment Networks by Project Establishment between Agents

We present an investment model integrated with trust-reputation mechanisms where agents interact with each other to establish investment projects. We investigate the establishment of investment projects, the influence of the interaction between agents in the evolution of the distribution of wealth, as well as the formation of common investment networks and some of their properties. Simulation results show that the wealth distribution presents a power law in its tail. Also, it is shown that the trust and reputation mechanism presented leads to the establishment of networks among agents, which present some of the typical characteristics of real-life networks like a high clustering coefficient and short average path length

The Strategic Exploitation of Limited Information and Opportunity in Networked Markets

This paper studies the effect of constraining interactions within a market. A model is analysed in which boundedly rational agents trade with and gather information from their neighbours within a trade network. It is demonstrated that a trader’s ability to profit and to identify the equilibrium price is positively correlated with its degree of connectivity within the market. Where traders differ in their number of potential trading partners, well-connected traders are found to benefit from aggressive trading behaviour.Where information propagation is constrained by the topology of the trade network, connectedness affects the nature of the strategies employed

Creating wheelchair-controlled video games: challenges and opportunities when involving young people with mobility impairments and game design experts

Although participatory design (PD) is currently the most acceptable and respectful process we have for designing technology, recent discussions suggest that there may be two barriers to the successful application of PD to the design of digital games: First, the involvement of audiences with special needs can introduce new practical and ethical challenges to the design process. Second, the use of non-experts in game design roles has been criticised in that participants lack skills necessary to create games of appropriate quality. To explore how domain knowledge and user involvement influence game design, we present results from two projects that addressed the creation of movement-based wheelchair-controlled video games from different perspectives. The first project was carried out together with a local school that provides education for young people with special needs, where we invited students who use wheelchairs to take part in design sessions. The second project involved university students on a game development course, who do not use wheelchairs, taking on the role of expert designers. They were asked to design concepts for wheelchair-controlled games as part of a final-year course on game design. Our results show that concepts developed by both groups were generally suitable examples of wheelchair-controlled motion-based video games, but we observed differences regarding level of detail of game concepts, and ideas of disability. Additionally, our results show that the design exercise exposed vulnerabilities in both groups, outlining that the risk of practical and emotional vulnerability needs to be considered when working with the target audience as well as expert designers

Crises and collective socio-economic phenomena: simple models and challenges

Financial and economic history is strewn with bubbles and crashes, booms and busts, crises and upheavals of all sorts. Understanding the origin of these events is arguably one of the most important problems in economic theory. In this paper, we review recent efforts to include heterogeneities and interactions in models of decision. We argue that the Random Field Ising model (RFIM) indeed provides a unifying framework to account for many collective socio-economic phenomena that lead to sudden ruptures and crises. We discuss different models that can capture potentially destabilising self-referential feedback loops, induced either by herding, i.e. reference to peers, or trending, i.e. reference to the past, and account for some of the phenomenology missing in the standard models. We discuss some empirically testable predictions of these models, for example robust signatures of RFIM-like herding effects, or the logarithmic decay of spatial correlations of voting patterns. One of the most striking result, inspired by statistical physics methods, is that Adam Smith's invisible hand can badly fail at solving simple coordination problems. We also insist on the issue of time-scales, that can be extremely long in some cases, and prevent socially optimal equilibria to be reached. As a theoretical challenge, the study of so-called "detailed-balance" violating decision rules is needed to decide whether conclusions based on current models (that all assume detailed-balance) are indeed robust and generic.Comment: Review paper accepted for a special issue of J Stat Phys; several minor improvements along reviewers' comment

Creating wheelchair-controlled video games: challenges and opportunities when involving young people with mobility impairments and game design experts

Although participatory design (PD) is currently the most acceptable and respectful process we have for designing technology, recent discussions suggest that there may be two barriers to the successful application of PD to the design of digital games: First, the involvement of audiences with special needs can introduce new practical and ethical challenges to the design process. Second, the use of non-experts in game design roles has been criticised in that participants lack skills necessary to create games of appropriate quality. To explore how domain knowledge and user involvement influence game design, we present results from two projects that addressed the creation of movement-based wheelchair-controlled video games from different perspectives. The first project was carried out together with a local school that provides education for young people with special needs, where we invited students who use wheelchairs to take part in design sessions. The second project involved university students on a game development course, who do not use wheelchairs, taking on the role of expert designers. They were asked to design concepts for wheelchair-controlled games as part of a final-year course on game design. Our results show that concepts developed by both groups were generally suitable examples of wheelchair-controlled motion-based video games, but we observed differences regarding level of detail of game concepts, and ideas of disability. Additionally, our results show that the design exercise exposed vulnerabilities in both groups, outlining that the risk of practical and emotional vulnerability needs to be considered when working with the target audience as well as expert designers

Head-mounted Sensory Augmentation Device: Comparing Haptic and Audio Modality

This paper investigates and compares the effectiveness of haptic and audio modality for navigation in low visibility environment using a sensory augmentation device. A second generation head-mounted vibrotactile interface as a sensory augmentation prototype was developed to help users to navigate in such environments. In our experiment, a subject navigates along a wall relying on the haptic or audio feedbacks as navigation commands. Haptic/audio feedback is presented to the subjects according to the information measured from the walls to a set of 12 ultrasound sensors placed around a helmet and a classification algorithm by using multilayer perceptron neural network. Results showed the haptic modality leads to significantly lower route deviation in navigation compared to auditory feedback. Furthermore, the NASA TLX questionnaire showed that subjects reported lower cognitive workload with haptic modality although both modalities were able to navigate the users along the wall