A privacy awareness system for ubiquitous computing environments

www.inf.ethz.ch/˜langhein Abstract. Protecting personal privacy is going to be a prime concern for the deployment of ubiquitous computing systems in the real world. With daunting Orwellian visions looming, it is easy to conclude that tamper-proof technical protection mechanisms such as strong anonymization and encryption are the only solutions to such privacy threats. However, we argue that such perfect protection for personal information will hardly be achievable, and propose instead to build systems that help others respect our personal privacy, enable us to be aware of our own privacy, and to rely on social and legal norms to protect us from the few wrongdoers. We introduce a privacy awareness system targeted at ubiquitous computing environments that allows data collectors to both announce and implement data usage policies, as well as providing data subjects with technical means to keep track of their personal information as it is stored, used, and possibly removed from the system. Even though such a system cannot guarantee our privacy, we believe that it can create a sense of accountability in a world of invisible services that we will be comfortable living in and interacting with.

Social Ranking Techniques for the Web

The proliferation of social media has the potential for changing the structure and organization of the web. In the past, scientists have looked at the web as a large connected component to understand how the topology of hyperlinks correlates with the quality of information contained in the page and they proposed techniques to rank information contained in web pages. We argue that information from web pages and network data on social relationships can be combined to create a personalized and socially connected web. In this paper, we look at the web as a composition of two networks, one consisting of information in web pages and the other of personal data shared on social media web sites. Together, they allow us to analyze how social media tunnels the flow of information from person to person and how to use the structure of the social network to rank, deliver, and organize information specifically for each individual user. We validate our social ranking concepts through a ranking experiment conducted on web pages that users shared on Google Buzz and Twitter.Comment: 7 pages, ASONAM 201

Effects of experimental warming and carbon addition on nitrate reduction and respiration in coastal sediments

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Biogeochemistry 125 (2015): 81-95, doi:10.1007/s10533-015-0113-4.Climate change may have differing effects on microbial processes that control coastal N availability. We conducted a microcosm experiment to explore effects of warming and carbon availability on nitrate reduction pathways in marine sediments. Sieved continental shelf sediments were incubated for 12 weeks under aerated seawater amended with nitrate (~50 μM), at winter (4°C) or summer (17°C) temperatures, with or without biweekly particulate organic C additions. Treatments increased diffusive oxygen consumption as expected, with somewhat higher effects of C addition compared to warming. Combined warming and C addition had the strongest effect on nitrate flux across the sediment water interface, with a complete switch early in the experiment from influx to sustained efflux. Supporting this result, vial incubations with added 15N-nitrate indicated that C addition stimulated potential rates of dissimilatory nitrate reduction to ammonium (DNRA), but not denitrification. Overall capacity for both denitrification and DNRA was reduced in warmed treatments, possibly reflecting C losses due to increased respiration with warming. Anammox potential rates were much lower than DNRA or denitrification, and were slightly negatively affected by warming or C addition. Overall, results indicate that warming and C addition increased ammonium production through remineralization and possibly DNRA. This stimulated nitrate production through nitrification, but without a comparable increase in nitrate consumption through denitrification. The response to C of potential DNRA rates over denitrification, along with a switch to nitrate efflux, raises the possibility that DNRA is an important and previously overlooked source of internal N cycling in shelf sediments.This material is based upon work supported by the National Science Foundation by OCE- 0852289 to JJR and OCE-0852263 and OCE-0927400 to AEG, and Rhode Island Sea Grant to JJR

Similar temperature responses suggest future climate warming will not alter partitioning between denitrification and anammox in temperate marine sediments

Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Global Change Biology 23 (2017): 331-340, doi:10.1111/gcb.13370.Removal of biologically available nitrogen (N) by the microbially mediated processes denitrification and anaerobic ammonium oxidation (anammox) affects ecosystem N availability. Although few studies have examined temperature responses of denitrification and anammox, previous work suggests that denitrification could become more important than anammox in response to climate warming. To test this hypothesis, we determined whether temperature responses of denitrification and anammox differed in shelf and estuarine sediments from coastal Rhode Island over a seasonal cycle. The influence of temperature and organic C availability was further assessed in a 12-week laboratory microcosm experiment. Temperature responses, as characterized by thermal optima (Topt) and apparent activation energy (Ea), were determined by measuring potential rates of denitrification and anammox at 31 discrete temperatures ranging from 3 to 59°C. With a few exceptions, Topt and Ea of denitrification and anammox did not differ in Rhode Island sediments over the seasonal cycle. In microcosm sediments, Ea was somewhat lower for anammox compared to denitrification across all treatments. However, Topt did not differ between processes, and neither Ea nor Topt changed with warming or carbon addition. Thus, the two processes behaved similarly in terms of temperature response, and this response was not influenced by warming. This led us to reject the hypothesis that anammox is more cold-adapted than denitrification in our study system. Overall, our study suggests that temperature responses of both processes can be accurately modeled for temperate regions in the future using a single set of parameters, which are likely not to change over the next century as a result of predicted climate warming. We further conclude that climate warming will not directly alter the partitioning of N flow through anammox and denitrification.This material is based upon work supported by the National Science Foundation under Grant No. OCE-0852289 to JJR and OCE-0852263, OCE-0927400 and OCE1238212 to AEG, and Rhode Island Sea Grant to JJR.2017-05-2

Fractal Weyl law for quantum fractal eigenstates

The properties of the resonant Gamow states are studied numerically in the semiclassical limit for the quantum Chirikov standard map with absorption. It is shown that the number of such states is described by the fractal Weyl law and their Husimi distributions closely follow the strange repeller set formed by classical orbits nonescaping in future times. For large matrices the distribution of escape rates converges to a fixed shape profile characterized by a spectral gap related to the classical escape rate.Comment: 4 pages, 5 figs, minor modifications, research at http://www.quantware.ups-tlse.fr

Cross-linguistic study of vocal pathology: perceptual features of spasmodic dysphonia in French-speaking subjects

Clinical characterisation of Spasmodic Dysphonia of the adductor type (SD) in French speakers by Klap and colleagues (1993) appears to differ from that of SD in English. This perceptual analysis aims to describe the phonetic features of French SD. A video of 6 French speakers with SD supplied by Klap and colleagues was analysed for frequency of phonatory breaks, pitch breaks, harshness, creak, breathiness and falsetto voice, rate of production, and quantity of speech output. In contrast to English SD, the French speaking SD patients demonstrated no evidence pitch breaks, but phonatory breaks, harshness and breathiness were prominent features. This verifies the French authors’ (1993) clinical description. These findings suggest that phonetic properties of a specific language may affect the manifestation of pathology in neurogenic voice disorders

Two-dimensional ranking of Wikipedia articles

The Library of Babel, described by Jorge Luis Borges, stores an enormous amount of information. The Library exists {\it ab aeterno}. Wikipedia, a free online encyclopaedia, becomes a modern analogue of such a Library. Information retrieval and ranking of Wikipedia articles become the challenge of modern society. While PageRank highlights very well known nodes with many ingoing links, CheiRank highlights very communicative nodes with many outgoing links. In this way the ranking becomes two-dimensional. Using CheiRank and PageRank we analyze the properties of two-dimensional ranking of all Wikipedia English articles and show that it gives their reliable classification with rich and nontrivial features. Detailed studies are done for countries, universities, personalities, physicists, chess players, Dow-Jones companies and other categories.Comment: RevTex 9 pages, data, discussion added, more data at http://www.quantware.ups-tlse.fr/QWLIB/2drankwikipedia

You can't see what you can't see: Experimental evidence for how much relevant information may be missed due to Google's Web search personalisation

The influence of Web search personalisation on professional knowledge work is an understudied area. Here we investigate how public sector officials self-assess their dependency on the Google Web search engine, whether they are aware of the potential impact of algorithmic biases on their ability to retrieve all relevant information, and how much relevant information may actually be missed due to Web search personalisation. We find that the majority of participants in our experimental study are neither aware that there is a potential problem nor do they have a strategy to mitigate the risk of missing relevant information when performing online searches. Most significantly, we provide empirical evidence that up to 20% of relevant information may be missed due to Web search personalisation. This work has significant implications for Web research by public sector professionals, who should be provided with training about the potential algorithmic biases that may affect their judgments and decision making, as well as clear guidelines how to minimise the risk of missing relevant information.Comment: paper submitted to the 11th Intl. Conf. on Social Informatics; revision corrects error in interpretation of parameter Psi/p in RBO resulting from discrepancy between the documentation of the implementation in R (https://rdrr.io/bioc/gespeR/man/rbo.html) and the original definition (https://dl.acm.org/citation.cfm?id=1852106) as per 20/05/201

Google matrix of business process management

Development of efficient business process models and determination of their characteristic properties are subject of intense interdisciplinary research. Here, we consider a business process model as a directed graph. Its nodes correspond to the units identified by the modeler and the link direction indicates the causal dependencies between units. It is of primary interest to obtain the stationary flow on such a directed graph, which corresponds to the steady-state of a firm during the business process. Following the ideas developed recently for the World Wide Web, we construct the Google matrix for our business process model and analyze its spectral properties. The importance of nodes is characterized by Page-Rank and recently proposed CheiRank and 2DRank, respectively. The results show that this two-dimensional ranking gives a significant information about the influence and communication properties of business model units. We argue that the Google matrix method, described here, provides a new efficient tool helping companies to make their decisions on how to evolve in the exceedingly dynamic global market.Comment: submitted to European Journal of Physics