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African savanna ecosystems are home to the world's richest large herbivore (LH) assemblages. However, its landscapes are changing faster than any other region on Earth due to human activities and natural events. Therefore, understanding the factors influencing the distribution of LH in these human‐dominated environments is crucial for decision‐making on wildlife and habitat management. We combined ecological aerial surveys, camera trap, and dung count data to investigate how ecological (habitat types, perennial rivers, and rainfall) and anthropogenic (human settlements and cattle grazing areas) factors influence the distribution of LH species in Limpopo National Park (LNP). We used generalized linear models fitting binary logistic regression models to distinguish 25‐km2 cells occupied (where the species were detected) by elephants (Loxodonta africana), buffalos (Syncerus caffer), zebras (Equus quagga), kudus (Tragelaphus strepsiceros), nyalas (Tragelaphus angasii), and impalas (Aepyceros melampus) from unoccupied regions (where the species were not detected) in the LNP landscape. We found that habitat type and rainfall were the most influential factors shaping the pattern of LH distribution in the LNP, except for elephants, whose prevalence was not associated with rainfall. The prevalence of zebras was positively associated with the proximity to perennial rivers, while kudus avoided these areas. While some species (zebras, kudus, and impalas) tended to avoid settlements, others (elephants, buffalos, and nyala) seemed attracted to settlements. Cattle grazing areas were the worst predictors of the distribution of all study species. Our results disclosed the role of ecological factors for the distribution of LH and showed that anthropogenic disturbances seemed to either (partially) prevent the occurrence of LH or show the potential for human–wildlife conflict risk in the study area. Therefore, the results highlight the need to investigate/quantify the potential human–wildlife conflict risk at finer spatial scales to improve future management. [ABSTRACT FROM AUTHOR]

Abstract Savannas are characterized by the co-occurrence of two different plant life forms: grasses and trees. Herbivory plays a major role in the balance between grasses and trees in savanna ecosystems. The present study aimed to investigate the impact and interactions between long-term (i.e. 20 years) herbivory and/or its exclusion and plant life form on the soil biochemistry of a protected semi-arid savanna ecosystem in the Kruger National Park (KNP), South Africa. To study the effects of herbivory on soil properties, herbivore exclosures (fully fenced areas, partially fenced areas, and an unfenced area) were used in conjunction with plant life form (trees and grasses) were considered. Interaction effects of herbivory and plant life form on soil pH, electrical conductivity (EC), total nitrogen (TN), total carbon (TC), available phosphorus (available P), exchangeable cations (K+, Na+, Mg2+ and Ca2+) cation exchange capacity (CEC), organic matter (OM) and total microbial activity were determined on savanna soils in the Nkuhlu exclosures, KNP. Exclosures where herbivores were present had significantly higher soil pH, The presence of herbivores caused an increase in soil pH, EC, exchangeable Na, CEC, and OM. The influence of the tree canopy was significantly more pronounced in elevating total C and N, exchangeable K+, Mg2+ and Ca2+, CEC and OM than observed in the open grassland zones across all exclosures. The two-way interaction between herbivory and plant life form resulted in significant decreases in TN, TC, exchangeable K, Na and Mg in open grassland areas outside of herbivore exclosures where large animals had direct access, as compared to areas within the exclosures which was protected from animal entry herbivory. This data can be used by national parks as an indicator to increase their knowledge of environmental issues relating to maintaining and preserving landscape features of savannas.

Abstract African savanna ecosystems are home to the world's richest large herbivore (LH) assemblages. However, its landscapes are changing faster than any other region on Earth due to human activities and natural events. Therefore, understanding the factors influencing the distribution of LH in these human‐dominated environments is crucial for decision‐making on wildlife and habitat management. We combined ecological aerial surveys, camera trap, and dung count data to investigate how ecological (habitat types, perennial rivers, and rainfall) and anthropogenic (human settlements and cattle grazing areas) factors influence the distribution of LH species in Limpopo National Park (LNP). We used generalized linear models fitting binary logistic regression models to distinguish 25‐km2 cells occupied (where the species were detected) by elephants (Loxodonta africana), buffalos (Syncerus caffer), zebras (Equus quagga), kudus (Tragelaphus strepsiceros), nyalas (Tragelaphus angasii), and impalas (Aepyceros melampus) from unoccupied regions (where the species were not detected) in the LNP landscape. We found that habitat type and rainfall were the most influential factors shaping the pattern of LH distribution in the LNP, except for elephants, whose prevalence was not associated with rainfall. The prevalence of zebras was positively associated with the proximity to perennial rivers, while kudus avoided these areas. While some species (zebras, kudus, and impalas) tended to avoid settlements, others (elephants, buffalos, and nyala) seemed attracted to settlements. Cattle grazing areas were the worst predictors of the distribution of all study species. Our results disclosed the role of ecological factors for the distribution of LH and showed that anthropogenic disturbances seemed to either (partially) prevent the occurrence of LH or show the potential for human–wildlife conflict risk in the study area. Therefore, the results highlight the need to investigate/quantify the potential human–wildlife conflict risk at finer spatial scales to improve future management.

Savannas are characterized by the co-occurrence of two different plant life forms: grasses and trees. Herbivory plays a major role in the balance between grasses and trees in savanna ecosystems. The present study aimed to investigate the impact and interactions between long-term (i.e. 20 years) herbivory and/or its exclusion and plant life form on the soil biochemistry of a protected semi-arid savanna ecosystem in the Kruger National Park (KNP), South Africa. To study the effects of herbivory on soil properties, herbivore exclosures (fully fenced areas, partially fenced areas, and an unfenced area) were used in conjunction with plant life form (trees and grasses) were considered. Interaction effects of herbivory and plant life form on soil pH, electrical conductivity (EC), total nitrogen (TN), total carbon (TC), available phosphorus (available P), exchangeable cations (K+, Na+, Mg2+ and Ca2+) cation exchange capacity (CEC), organic matter (OM) and total microbial activity were determined on savanna soils in the Nkuhlu exclosures, KNP. Exclosures where herbivores were present had significantly higher soil pH, The presence of herbivores caused an increase in soil pH, EC, exchangeable Na, CEC, and OM. The influence of the tree canopy was significantly more pronounced in elevating total C and N, exchangeable K+, Mg2+ and Ca2+, CEC and OM than observed in the open grassland zones across all exclosures. The two-way interaction between herbivory and plant life form resulted in significant decreases in TN, TC, exchangeable K, Na and Mg in open grassland areas outside of herbivore exclosures where large animals had direct access, as compared to areas within the exclosures which was protected from animal entry herbivory. This data can be used by national parks as an indicator to increase their knowledge of environmental issues relating to maintaining and preserving landscape features of savannas. [ABSTRACT FROM AUTHOR]

Introduction: The wide range of the perceived value dimensions in the field of consumer behavior has led the present study to investigate the perceived value of shopping centers and malls in Iran, its antecedents and consequents and how they affect each other. The mixed research approach is a sequential-heuristic one. In the qualitative section, the hermeneutic phenomenology method was applied to explore the lived experience of the participants. On the whole, eighteen informants were selected based on the snowball sampling method for deep interviews. The data were analyzed by using coding and sequential mixed data analysis via the Atlasti software. Finally, thirty three themes were extracted. In the quantitative part, the descriptive survey method was used. The data were collected from mall browsers through a questionnaire. Structural equation modeling was done via the AMOS software to analyze the model. According to the findings, there were eight values including economic, hedonic, escapism, epistemic, time convenience, utilitarian, status and Islamic values. All the dimensions of the perceived value had a significant positive effect on loyalty. Using a mixed approach, this study has introduced some new categories and themes about perceived value and its antecedents from the perspective of Iranian customers going to shopping centers.Methodology: In the current research, a mixed approach consisting of two parts, quantitative and qualitative, has been used. In the qualitative part of the research, the sampling is based on the purpose. Eighteen people who referred to shopping centers were selected to participate in the qualitative part of the research using the snowball method. In order to collect the data, in-depth interviews were conducted with the participants based on the interview protocol. The data were analyzed by using a coding method similar to the coding method in the grounded theory and with the help of the Atlas t software. In the quantitative part, it is an applied research in terms of its purpose. In terms of the method, it is a descriptive research of a survey type. Also, this study is cross-sectional based on the level of in-depth observation. In this part, the findings obtained from the qualitative section were used to design a questionnaire and develop a tool to measure the concept of the perceived value of the shopping center and malls. The structural equation modeling method was used with the help of the AMOS software to analyze quantitative data.Result and Discussion: In the first stage of coding, which is called open coding, 1,188 open codes were discovered, and then, after repeated refinement, they were organized into eighty-seven more abstract concepts called categories. Then, the categories were classified into thirty three themes. The results of the present research can be divided into three general categories. The first to eleventh themes reflect the structure of the perceived value of the shopping centers and malls. The twelfth to twenty-seventh themes represent the anticipants of the perceived value of the shopping centers and malls. The 28th to 33rd themes refer the consequences of the perceived value of the shopping centers and malls. In the quantitative part of the research, namely the exploratory factor analysis, 60 items were loaded in fifteen components. These items were measured on a five-point Likert scale ranging from completely disagree to completely agree. In the end, a model with 28 paths remained on the perceived values positively and significantly. As the results of the model fit indicate, the fit index has the necessary values ​​and supports the agreement between the experimental data and the extracted model. The indices of the final model were NFI: 0.832, CFI: 0.907, GFI: 0.825, AGFI: 0.808, RMSEA: 0.43. The results extracted for the model indicated that the items of each component had a positive loading factor greater than 0.50, and the calculated t-value for each of them was greater than 1.96 and 2.58. All the path coefficients were significant at the 95% confidence level. There were eight perceived value components of shopping centers including economic, hedonic, escapism, epistemic, time convenience, utilitarian, status and Islamic components. According to the results of the current research model, behavioural consequences (loyalty) are significantly influenced by all these eight components.Conclusion: Due to the fact that the number of shopping centers and homogeneous malls is increasing day by day and the needs and demands of customers get to be more complex and diverse, managers of shopping centers who understand the reasons for appropriate behavior have competitive advantages. They can use the knowledge in this field to maintain the existing customers and convince new customers from among the competitors, to present a distinctive image of the shopping centers under their management. The researchers in the present study, influenced by native values, reached factors such as environmental features, internal motivators, the nature of the shopping center, sports and health facilities, facilities for children and visual attractions. The number of factors affecting the choice of shopping centers are different based on the country of study. Shopping centers are considered more profitable if they satisfy both types of buyers with values ​​of hedonism and utilitarianism. This result leads to the support of the customers who desire to stay longer in shopping centers, increase patronage and spend more money. The present study has explained the value structures of customers' shopping experience and identified various factors that make customers want to visit shopping centers.

We used a long-term herbivore removal experiment where paired exclosure–open treatments were established at the Mpala Research Centre, Laikipia, Kenya, in 1999 to examine changes in soil nitrogen (N) at nutrient-rich glades and adjacent nutrient-poor bushland sites after almost two decades of herbivore removal. Glades in this landscape are created by large inputs of dung and urine from previous long-term corralling of cattle in an otherwise nutrient-poor matrix of woodland (bushland). We predicted (1) a net gain of soil nutrients at bushland sites (that is, inputs of nutrients > losses) and (2) a net loss of soil nutrients at glade sites (that is, inputs of nutrients < losses) following herbivore exclusion. As expected, soil N increased (by 28% after 17 years) with herbivore removal, but remained largely unchanged in the presence of herbivores at low-nutrient bushland sites. However, contrary to our expectations, soil total N in nutrient-rich glades also increased (+ 18%) when herbivores were removed, but declined when grazed (− 11%). Although the underlying mechanisms are unclear, we suggest that increased N fixation by Acacia spp., combined with increased canopy cover and associated tree leaf litter, resulted in elevated soil N following browser removal in low-nutrient bushland sites, while grazer-induced increases in the rate of N transformations between organic and mineral forms resulted in a more "open" N cycle (as evidenced by higher N mineralization rates and foliar N), with increased potential for N loss in gaseous forms, in grazed nutrient-rich glade sites. Grazers and browsers thus appear to affect the N cycle and create and reinforce heterogeneity in unique ways. [ABSTRACT FROM AUTHOR]

Fuelbreaks are used to manage wildfires worldwide. Regular mowing within fuelbreaks can alter species composition and transform them into grassland habitats. These changes may provide more herbaceous plants to large herbivores, subsequently influencing their distribution. To clarify the impact of fuelbreaks on herbivores' food resources, we conducted molecular dietary analysis to quantify the dietary composition of sika deer (Cervus nippon) in both the Sino-Russian border fuelbreak and forest interior, with an average distance of 1.6 km away from the fuelbreak. We constructed a local barcode database to enhance the resolution of the molecular dietary analysis. In addition, we surveyed the vegetation in these two habitats to determine the availability of food resources. We also used camera traps to monitor the visitation intensity of sika deer in both habitats. The results indicated that sika deer increased their visitation intensity at the fuelbreak during the snow-free season. The biomass of graminoids and herbaceous plants was high in the fuelbreak. However, the results of the molecular dietary analysis showed that during the snow-free season, the sika deer that visited the fuelbreak consumed fewer herbaceous plants. We used the Jacobs index to determine the dietary preferences of the sika deer and found that they were consistent browsers with a stable preference for woody plants. By assessing habitat quality, specifically the proportion of preferred plants, we found that the habitat quality of the fuelbreak was relatively low. In conclusion, fuelbreaks may attract herbivores. However, for browsers, such as sika deer, the major function of fuelbreaks is not to provide food resources. • Molecular dietary analysis reveals the diet of the sika deer. • Sika deer consistently prefer woody plants and they are browsers. • Fuelbreaks have a lower proportion of palatable plants for sika deer. • For browsers, the major function of fuelbreaks is not to provide food resources. • Sika deer increased their visits at the fuelbreak during the snow-free season. [ABSTRACT FROM AUTHOR]

Genomic research emerges from collaborative work within and across different scientific disciplines. A diverse range of visualisation techniques has been employed to aid this research, yet relatively little is known as to how these techniques facilitate collaboration. We conducted a case study of collaborative research within a biomedical institute to learn more about the role visualisation plays in genomic mapping. Interviews were conducted with molecular biologists (N = 5) and bioinformaticians (N = 6). We found that genomic research comprises a variety of distinct disciplines engaged in complex analytic tasks that each resist simplification, and their complexity influences how visualisations were used. Visualisation use was impacted by group-specific interactions and temporal work patterns. Visualisations were also crucial to the scientific workflow, used for both question formation and confirmation of hypotheses, and acted as an anchor for the communication of ideas and discussion. In the latter case, two approaches were taken: providing collaborators with either interactive or static imagery representing a viewpoint. The use of generic software for simplified visualisations, and quick production and curation was also noted. We discuss these findings with reference to group-specific interactions and present recommendations for improving collaborative practices through visual analytics. [ABSTRACT FROM AUTHOR]

Elicitation studies have become a popular method of participatory design. While traditionally used to examine unimodal gesture interactions, elicitation has started being used with other novel interaction modalities. Unfortunately, there has been no work that examines the impact of referent display on elicited interaction proposals. To address that concern this work provides a detailed comparison between two elicitation studies that were similar in design apart from the way that participants were prompted for interaction proposals (i.e., the referents). Based on this comparison the impact of referent display on speech and gesture interaction proposals are each discussed. The interaction proposals between these elicitation studies were not identical. Gesture proposals were the least impacted by referent display, showing high proposal similarity between the two works. Speech proposals were highly biased by text referents with proposals directly mirroring text-based referents an average of 69.36% of the time. In short, the way that referents are presented during elicitation studies can impact the resulting interaction proposals; however, the level of impact found is dependent on the modality of input elicited. [ABSTRACT FROM AUTHOR]

Modern mobile operating systems support displaying Web pages in native mobile applications. When an app user navigates to a specific location containing a Web page, the Web page will be loaded and rendered from within the app. Such kind of Web browsing, as we call embedded Web browsing, is different from traditional Web browsing, which involves typing a URL on a browser and loading the Web page. However, little has been known about the prevalence or performance of such embedded Web pages. In this paper, we conduct, to the best of our knowledge, the first measurement study on embedded Web browsing on Android. Our study on 22,521 popular Android apps shows that 57.9 and 73.8 percent of apps embed Web pages on two popular app markets, that is, Google Play and Wandoujia, respectively. We design and implement EWProfiler, a tool that can automatically search for embedded Web pages inside apps, trigger page loads, and retrieve performance metrics to analyze the embedded Web browsing performance at scale. Based on 445 embedded Web pages obtained by EWProfiler in 99 popular apps from the two app markets, we investigate the characteristics and performance of embedded Web pages, and find that embedded Web pages significantly impede the app user experience. We investigate the effectiveness of three techniques, i.e., separating the browser kernel to a different process, loading pages from the local storage, and pre-rendering, to optimize the performance of embedded Web browsing. We believe that our findings could draw the attention of Web developers, browser vendors, app developers, and mobile OS vendors together toward a better performance of embedded Web browsing. [ABSTRACT FROM AUTHOR]

The dominant markup language for Web visualizations—Scalable Vector Graphics (SVG)—is comparatively easy to learn, and is open, accessible, customizable via CSS, and searchable via the DOM, with easy interaction handling and debugging. Because these attributes allow visualization creators to focus on design on implementation details, tools built on top of SVG, such as D3.js, are essential to the visualization community. However, slow SVG rendering can limit designs by effectively capping the number of on-screen data points, and this can force visualization creators to switch to Canvas or WebGL. These are less flexible (e.g., no search or styling via CSS), and harder to learn. We introduce Scalable Scalable Vector Graphics (SSVG) to reduce these limitations and allow complex and smooth visualizations to be created with SVG. SSVG automatically translates interactive SVG visualizations into a dynamic virtual DOM (VDOM) to bypass the browser's slow ‘to specification’ rendering by intercepting JavaScript function calls. De-coupling the SVG visualization specification from SVG rendering, and obtaining a dynamic VDOM, creates flexibility and opportunity for visualization system research. SSVG uses this flexibility to free up the main thread for more interactivity and renders the visualization with Canvas or WebGL on a web worker. Together, these concepts create a drop-in JavaScript library which can improve rendering performance by 3–9× with only one line of code added. To demonstrate applicability, we describe the use of SSVG on multiple example visualizations including published visualization research. A free copy of this article, collected data, and source code are available as open science at osf.io/ge8wp. [ABSTRACT FROM AUTHOR]

Savanna tree cover often exhibits sudden discontinuities across space. It has been proposed that local spatial processes imposed by variation in tree cover itself (as opposed to by external drivers such as edaphic variation) can reinforce such discontinuities. Despite this, we generally lack data on tree demography and the environmental drivers affecting the former as a function of tree neighborhoods in these systems. Given the importance of disturbance traps in savannas, spatial processes affecting the likelihood of escape from the seedling/sapling stage to the adult tree stage are likely to be critical. In a longitudinal survey of 800 saplings distributed along eight 1‐km transects spanning woodland–grassland transitions in Serengeti National Park, we found a positive association between tree cover and sapling growth and survival, but no relationship with sapling abundance, maximum tree height, disturbance, or topkill. Based on microclimate and soil moisture dynamics data, we found no evidence to suggest that tree cover itself drives variation in growth. Based on a prior analysis of soil properties along these transects, we hypothesized that underlying edaphic conditions may be responsible for variation in growth. Regardless of the underlying mechanism, we used simulations to show that subtle growth rate gradients interacted with intense disturbance regimes to produce sharp discontinuities in tree cover, with strong demographic bottlenecks where growth is slowest, explaining the observed patterns of tree cover along the transects. Our results indicated that disturbance and herbivory are equally intense in areas of high and low tree cover, and that although trees have the potential to successfully establish and reach adulthood in open, grassy sites, they grow too slowly to escape disturbance traps there. Importantly, we showed that although herbivory and fire are fundamental for explaining savanna structural patterns, their effects are not necessarily reinforced by tree cover itself. [ABSTRACT FROM AUTHOR]

Abstract Research in the past decade has demonstrated that a single reference genome is not representative of a species’ diversity. MaizeGDB introduces a pan-genomic approach to hosting genomic data, leveraging the large number of diverse maize genomes and their associated datasets to quickly and efficiently connect genomes, gene models, expression, epigenome, sequence variation, structural variation, transposable elements, and diversity data across genomes so that researchers can easily track the structural and functional differences of a locus and its orthologs across maize. We believe our framework is unique and provides a template for any genomic database poised to host large-scale pan-genomic data.

Interrupting the web tracking kill chain is enough to disrupt the tracker's ability to leverage the collected information; however, this may disrupt the personalized services enjoyed by many. Empowering the user to select which domains can be co-tracked gives him/her the upper hand over web trackers. This allows the user to enjoy the personalized services without fearing full inter-domain tracking. To achieve this, we propose a solution that attempts to introduce layers of anonymization serving as temporary identities to be used by the user while browsing. Those identities will be used for limited time (to sustain the customization and user experience resulting from tracking), and then discarded for a new identity. This approach allows the user to divide the activity into profiles which eliminates browsing history spilling over to other sessions. We proved the security of this approach mathematically and we demonstrated its usability using an open-source Proof-of-Concept built on top of blockchain. [ABSTRACT FROM AUTHOR]

The measurement of response time in hypertext transfer protocol (HTTP) requests is the most basic proxy measurement method for evaluating Web browsing quality. It is used in the research literature and in application performance measurement instruments. During the development of a website, response time is obtained from in-browser measurements. After the website has been deployed, network traffic is used to continuously monitor activity, and the measurement data are used for service management and planning. In this study, we evaluate the accuracy of the measurements obtained from network traffic by comparing them with the in-browser measurement of resource load time. We evaluate the response times for encrypted and clear-text requests in an emulated network environment, in a laboratory deployment equivalent to a data centre network, and accessing popular Web sites on the public Internet. The accuracy for response time measurements obtained from network traffic is noticeable higher for Internet long distance paths than for low-delay paths (below 20 ms round-trip). The overhead of traffic encryption in secure HTTP requests has a negative effect on measurement accuracy, and we find relative measurement errors higher than 70% when using network traffic to infer HTTP response times compared with in-browser measurements. [ABSTRACT FROM AUTHOR]

To detect fraudulent TLS server certificates and improve the accountability of certification authorities (CAs), certificate transparency (CT) is proposed to record certificates in publicly-visible logs, from which the monitors fetch all certificates and watch for suspicious ones. However, if the monitors, either domain owners themselves or third-party services, fail to return a complete set of certificates issued for a domain of interest, potentially fraudulent certificates may not be detected and then the CT framework becomes less reliable. This paper presents the first systematic study on CT monitors. We analyze the data in 88 public logs and the services of 5 active third-party monitors regarding 3,000,431 certificates of 6,000 selected Alexa Top-1M websites. We find that although CT allows ordinary domain owners to act as monitors, it is impractical for them to perform reliable processing by themselves, due to the rapidly increasing volume of certificates in public logs (e.g., on average about 5 million records or 28.29 GB daily for the minimal set of logs that need to be monitored in 2018, or more than 7 million records per day in 2020, according to the Chrome CT policy). Moreover, our study discloses that (${a}$) none of the third-party monitors guarantees to return the complete set of certificates for a domain, and (${b}$) for some domains, even the union of the certificates returned by the five third-party monitors can probably be incomplete. As a result, the certificates accepted by CT-enabled browsers are not actually visible to the claimed domain owners, even when CT is adopted with well-functioning logs. The risk of invisible fraudulent certificates in public logs raises doubts on the reliability of CT in practice. [ABSTRACT FROM AUTHOR]

This work considers active deanonymization of bipartite networks. The scenario arises naturally in evaluating privacy in various applications such as social networks, mobility networks, and medical databases. For instance, in active deanonymization of social networks, an anonymous victim is targeted by an attacker (e.g. the victim visits the attacker’s website), and the attacker queries her group memberships (e.g. by querying the browser history) to deanonymize her. In this work, the fundamental limits of privacy, in terms of the minimum number of queries necessary for deanonymization, is investigated. A stochastic model is considered, where 1) the bipartite network of group memberships is generated randomly; 2) the attacker has partial prior knowledge of the group memberships; and 3) it receives noisy responses to its real-time queries. The bipartite network is generated based on linear and sublinear preferential attachment, and the stochastic block model. The victim’s identity is chosen randomly based on a distribution modeling the users’ risk of being the victim (e.g. probability of visiting the website). An attack algorithm is proposed which builds upon techniques from communication with feedback, and its performance, in terms of expected number of queries, is analyzed. Simulation results are provided to verify the theoretical derivations. [ABSTRACT FROM AUTHOR]

We formulate and study the problem of ON-OFF privacy. ON-OFF privacy algorithms enable a user to continuously switch his privacy between ON and OFF. An obvious example is the incognito mode in internet browsers. But beyond internet browsing, ON-OFF privacy can be a desired feature in most online applications. The challenge is that the statistical correlation over time of a user’s online behavior can lead to leakage of information. We consider the setting in which a user is interested in retrieving the latest message generated by one of $N$ sources. The user’s privacy status can change between ON and OFF over time. When privacy is ON the user wants to hide his request. Moreover, since the user’s requests depend on personal attributes such as age, gender, and political views, they are typically correlated over time. As a consequence, the user cannot simply ignore privacy when privacy is OFF. We model the correlation between user’s requests by an $N$ state Markov chain. The goal is to design query schemes with optimal download rate, that preserve privacy in an ON-OFF privacy setting. In this paper, we present inner and outer bounds on the achievable download rate for $N$ sources. We also devise an efficient algorithm to construct an ON-OFF privacy scheme achieving the inner bound and prove its optimality in the case $N=2$ sources. For $N > 2$ , finding tighter outer bounds and efficient constructions of ON-OFF privacy schemes that would achieve them remains an open question. [ABSTRACT FROM AUTHOR]

Certificate Transparency is a maturing system to provide visibility into the certificates that are issued as part of the web's public key infrastructure. In this article, we survey the history of Certificate Transparency deployment so far and discuss ongoing engineering and research challenges. [ABSTRACT FROM AUTHOR]

This article studies the feasibility of using a botnet to automate stock market manipulation, incorporating data from U.S. Securities and Exchange Commission case files, security surveys of online retail brokerage accounts, and dark web marketplace listings. [ABSTRACT FROM AUTHOR]

Research in Information-Centric Networking (ICN) and Named Data Networking (NDN) has produced many protocol designs and software prototypes, but they need to be validated and evaluated by real usage on the Internet, which is also critical to the realization of the ICN/NDN vision in the long run. This article presents the first Internet-scale adaptive video streaming service over NDN, which allows regular users to watch videos using NDN technology with no software installation or manual configuration. Since mid-2019, the official NDN website [1] has started using our service to deliver its videos to Internet users over the global NDN testbed, showcasing the feasibility of NDN. We conduct real-world experiments on the NDN testbed to validate the proper implementation of the client, network, and server sides of the proposed system and also evaluate the performance of our video streaming service. [ABSTRACT FROM AUTHOR]

Research in the past decade has demonstrated that a single reference genome is not representative of a species' diversity. MaizeGDB introduces a pan-genomic approach to hosting genomic data, leveraging the large number of diverse maize genomes and their associated datasets to quickly and efficiently connect genomes, gene models, expression, epigenome, sequence variation, structural variation, transposable elements, and diversity data across genomes so that researchers can easily track the structural and functional differences of a locus and its orthologs across maize. We believe our framework is unique and provides a template for any genomic database poised to host large-scale pan-genomic data. [ABSTRACT FROM AUTHOR]

We present VRIA, a Web-based framework for creating Immersive Analytics (IA) experiences in Virtual Reality. VRIA is built upon WebVR, A-Frame, React and D3.js, and offers a visualization creation workflow which enables users, of different levels of expertise, to rapidly develop Immersive Analytics experiences for the Web. The use of these open-standards Web-based technologies allows us to implement VR experiences in a browser and offers strong synergies with popular visualization libraries, through the HTML Document Object Model (DOM). This makes VRIA ubiquitous and platform-independent. Moreover, by using WebVR's progressive enhancement, the experiences VRIA creates are accessible on a plethora of devices. We elaborate on our motivation for focusing on open-standards Web technologies, present the VRIA creation workflow and detail the underlying mechanics of our framework. We also report on techniques and optimizations necessary for implementing Immersive Analytics experiences on the Web, discuss scalability implications of our framework, and present a series of use case applications to demonstrate the various features of VRIA. Finally, we discuss current limitations of our framework, the lessons learned from its development, and outline further extensions. [ABSTRACT FROM AUTHOR]

Web 2.0 application based on JavaScript is a wide-spread application domain today as it delivers rich, interactive user experiences. However, with the increasing number of browsers and platforms on which the applications can be executed, cross-browser incompatibilities (XBIs) are becoming a serious problem for organizations to develop modern JavaScript-based Web applications. Although lots of XBIs detection techniques have been proposed, there are still some limitations: 1) existing techniques are prone to generating certain false positives/negatives that result from the fact that they ignore non-deterministic events (e.g., timer, asynchronous request/response) inside the browser; 2) detection process is inefficient, as the same elements located in different pages will be repeatedly checked even if they stay unchanged after an event is triggered. Leveraging existing record/replay technique, we proposed X-Check, a novel cross-browser testing technique, which supports automated XBIs detection effectively. To improve the efficiency of XBIs detection, this paper further designed an incremental detection algorithm by only checking DOM-mutated and layout-changed nodes. Our empirical evaluation shows that X-Check is effective and efficient. For the selected 21 real-world Web applications, it identifies XBIs with a fairly high precision (83 percent) and recall (93 percent), and improves the performance of XBIs detection about 5.79 times compared to its non-optimized version. [ABSTRACT FROM AUTHOR]

Due to their heavy reliance on server infrastructure, the current computation-intensive SaaS suffer from scalability issues compared to the existing data-intensive commercial SaaS. Offloading certain computations to the client browser can resolve these scalability issues but the current Browser APIs are complex to use and integrate in a single software. We propose in this paper four high level APIs that harness existing browser-based paradigms and proven software architectures to reduce the complexity of parallel computing and device-agnostic interactive rendering in the web browser. To allow experimental results, we have developed a proof-of-concept browser-based and interactive diffusion MRI where we have particularly deployed a parallel Diffusion Tensor Estimation. Our platform provides us easy APIs achieving up to 4 times speedup in parallel computation and real-time interactive rendering performances across different Browsers and Devices in comparison to other existing solutions in the Diffusion MRI Community. [ABSTRACT FROM AUTHOR]

To validate a certificate, a user needs to install the certificate of the root certification authority (CA) and download the certificate revocation information (CRI). Although operating systems and browsers manage the certificate trust list (CTL) of publicly-trusted root CAs for global users, locally-trusted root CAs still play an important role and it is difficult for a user to manage its CTL properly by itself. Meanwhile, the CRI access is inefficient, sometimes even unavailable, and causes privacy leakage. We revisit these problems by analyzing the TLS sessions within an organization. To the best of our knowledge, we are the first to analyze CTL management and CRI access on the scale of medium-sized organizations. Based on the analysis, a locally-centralized design is proposed to manage the CTLs of all users by IT administrators and access the CRI services for all users, within an organization. We apply this design to desktop virtualization systems to demonstrate its applicability, and build vCertGuard with oVirt and KVM-QEMU. In vCertGuard, the CTLs of all virtual machines (VMs) are managed in the VM monitors (VMMs). In the CTL, the self-signed certificates of publicly-trusted root CAs are properly configured, while each locally-trusted certificate chain is specified one by one. vCertGuard accesses the CRI services for all VMs, and the downloaded CRI is cached and shared among VMs. Because most TLS servers are visited by multiple users of an organization, it reduces the cost of CRI access. Experimental results of the prototype system show that vCertGuard maintains the CTLs with a negligible overhead, and significantly improves the performance of CRI access. [ABSTRACT FROM AUTHOR]

In 2019, around 57% of the population of the world has broadband access to the Internet. Moreover, there are 5.9 billion mobile broadband subscriptions, i.e., 1.3 subscriptions per user. So there is an enormous interconnected computational power held by users all around the world. Also, it is estimated that Internet users spend more than six and a half hours online every day. But in spite of being a great amount of time, those resources are idle most of the day. Therefore, taking advantage of them presents an interesting opportunity. In this study, we introduce JSDoop, a prototype implementation to profit from this opportunity. In particular, we propose a volunteer web browser-based high-performance computing library. JSdoop divides a problem into tasks and uses different queues to distribute the computation. Then, volunteers access the web page of the problem and start processing the tasks in their web browsers. We conducted a proof-of-concept using our proposal and TensorFlow.js to train a recurrent neural network that predicts text. We tested it in a computer cluster and with up to 32 volunteers. The experimental results show that training a neural network in distributed web browsers is feasible and accurate, has a high scalability, and it is an interesting area for research.

Web prefetching is a key technology to hide network latencies from users. Conventional prefetching methods, however, misconstrue the purpose of user’s browsing behaviors and resulting experience due to their dependence on statistical characteristics or metadata of individual Web applications. In this letter, we propose a predictive prefetching scheme, WebPrefetcher, which utilizes interaction events to decipher user’s genuine intention and context. Our intensive performance analysis results obtained with a real Web browser demonstrate that WebPrefetcher improves user-perceived quality of experience noticeably, outperforming competitive models. [ABSTRACT FROM AUTHOR]

The radical progress in web services has drained more attraction towards escalating the security of several applications that serve and interact with the Internet users. In order to get authenticated from servers, the users must disclose their secret information to the server such as password and username so that they can access distinct applications on the Web. Due to distinct security attacks, such secret credentials should be discouraged from being revealed. Moreover, it is vibrant to secure the systems from known attacks. In contrast to all known security attacks, the insider attack is considered devastating because the privileged insiders of a system can violate the secret credentials, which may lead towards irrecoverable damage to both the system and the user. Therefore, to ensure the security of the system from insider attacks, different protocols have been proposed. Very recently, Rajamanickam et al. “Insider attack protection: Lightweight password-based authentication techniques using ECC,” presented novel authentication scheme for insider attack protection. They claimed that their protocol not only prevents insider attack but it is also immune to several known security attacks. This comment discloses the non-trivial weaknesses in the authentication phase between client and server. We have identified that the adversary can successfully impersonate the entities communicating with each other through this protocol. Moreover, their protocol fails to offer forward and backward secrecy. Consequently, we suggest possible solution for attack resilience. [ABSTRACT FROM AUTHOR]

The fifth version of the Hypertext Markup Language (HTML) standard is widely adopted in the diverse landscape of browser vendors and their continuously upgrading releases. One primary feature of HTML5 is native multimedia playback. The browsers’ native implementations of multimedia support bring lots of benefits such as improved security but require thorough testing, especially on the web page of complex factor combinations according to our manual checking of publicly visible existing tests. This article employs the combinatorial testing technique to trigger failure-inducing factor combinations effectively and to locate them, guided by some extracted properties that cover browsers’ major workflow of processing multimedia. Results are analyzed to give objective suggestions for browser developers to cast light on the places that implementation enhancement could be made, and for web developers to avoid undesirable effects. [ABSTRACT FROM AUTHOR]

This article presents the design, development, and deployment of an interactive online teaching and learning platform to improve the students' understanding, through different visualization tools, of core concepts delivered in electromagnetics (EM) courses. The main advantage of such tools is that they require no download time, memory space, or heavy equipment. The platform (or hub) benefits from advances in mobile technology and Internet connectivity to overcome the limitations of past pedagogical approaches. Students can use these tools anytime, from anywhere, and on any portable device. [ABSTRACT FROM AUTHOR]

HyperText Transfer Protocol (HTTP) cookies are widely used on the web to enhance communication efficiency between a client and a server by storing stateful information. However, cookies may contain private and sensitive information about users. Thus, in order to guarantee the security of cookies, most web browsers and servers support not only Transport Layer Security (TLS) but also other mechanisms such as HTTP Strict Transport Security and cookie flags. However, a recent study has shown that it is possible to circumvent cookie flags in HTTPS by exploiting a vulnerability in HTTP software that allows message truncation. In this paper, we propose a novel cookie hijacking attack called $rotten~cookie$ which deactivates cookie flags even if they are protected by TLS by exploiting a weakness in HTTP in terms of integrity checks. According to our investigation, all major browsers ignore uninterpretable sections of the header of HTTP response messages and accept incorrect formats without any rejection. We demonstrate that, when combined with TLS or application vulnerabilities, this form of attack can obtain private cookies by removing cookie flags. Thus, the attacker can impersonate a legitimate user in the eyes of the server when cookies are used as an authentication token. We prove the practicality of our attack by demonstrating that our attack can lead five major web browsers to accept a cookie without any cookie flags. We thus present a mitigation strategy for the transport layer to preserve cookie security against our attack. [ABSTRACT FROM AUTHOR]

Recommender systems have been increasingly used in a variety of web services, providing a list of recommended items in which a user may have an interest. While important, recommender systems are vulnerable to various malicious attacks. In this paper, we study a new security vulnerability in recommender systems caused by web injection, through which malicious actors stealthily tamper any unprotected in-transit HTTP webpage content and force victims to visit specific items in some web services (even running HTTPS), e.g., YouTube. By doing so, malicious actors can promote their targeted items in those web services. To obtain a deeper understanding on the recommender systems of our interest (including YouTube, Yelp, Taobao, and 360 App market), we first conduct a measurement-based analysis on several real-world recommender systems by leveraging machine learning algorithms. Then, web injection is implemented in three different types of devices (i.e., computer, router, and proxy server) to investigate the scenarios where web injection could occur. Based on the implementation of web injection, we demonstrate that it is feasible and sometimes effective to manipulate the real-world recommender systems through web injection. We also present several countermeasures against such manipulations. [ABSTRACT FROM AUTHOR]

Most of the world's tropical coastal and shelf areas are heavily affected by anthropogenic activities, but the north-west shelf of Australia is considered a 'very low-impact' area. The role of herbivory on coral reefs is recognised, but most of that research comes from reefs with considerable land-based impacts. In this study we sampled the teleost community and evaluated herbivory on the reef platform at Browse Island, a small isolated island 200 km off north-western Australia, using several approaches: (1) tethering of macroalgae; (2) herbivore exclosures; and (3) video footage. In total, 99 teleost species from 26 families were identified. Turf algal consumption was evident and 18 teleost turf consumers were identified. In contrast, no evidence was found of herbivory on large macroalgae, and browsers, the only group able to consume macroalgae, were represented by just four species all belonging to the genus Naso. The lack of diversity among these specialist herbivores may be a consequence of the small surface area of the reef and the distance to other emergent reefs. Based on a model of top-down control of macroalgae, the reef is potentially vulnerable to disturbance. Small isolated reefs can have low resilience despite having low impacts from land. We sampled fish and evaluated herbivory on the reef platform at Browse Island, 200 km off north-western Australia. We found 99 fish species, 18 of which are known to eat turf, but only 4 that eat macroalgae. Fish were eating turf on the reef, but we found no evidence they were eating macroalgae. This may make the reef more vulnerable to overgrowth of algae in the future. [ABSTRACT FROM AUTHOR]

The Web is one of the most successful Internet applications. Yet, the quality of Web users’ experience is still largely impenetrable. Whereas Web performance is typically studied with controlled experiments, in this work we perform a large-scale study of a real site, Wikipedia, explicitly asking (a small fraction of its) users for feedback on the browsing experience. The analysis of the collected feedback reveals that 85% of users are satisfied, along with both expected (e.g., the impact of browser and network connectivity) and surprising findings (e.g., absence of day/night, weekday/weekend seasonality) that we detail in this paper. Also, we leverage user responses to build supervised data-driven models to predict user satisfaction which, despite including state-of-the art quality of experience metrics, are still far from achieving accurate results (0.62 recall of negative answers). Finally, we make our dataset publicly available, hopefully contributing in enriching and refining the scientific community knowledge on Web users’ QoE. [ABSTRACT FROM AUTHOR]

Although studies have shown that mammalian herbivores often limit aboveground carbon storage in savannas, their effects on belowground soil carbon storage remain unclear. Using three sets of long‐term, large herbivore exclosures with paired controls, we asked how almost two decades of herbivore removal from a semiarid savanna in Laikipia, Kenya affected aboveground (woody and grass) and belowground soil carbon sequestration, and determined the major source (C3 vs. C4) of belowground carbon sequestered in soils with and without herbivores present. Large herbivore exclusion, which included a diverse community of grazers, browsers, and mixed‐feeding ungulates, resulted in significant increases in grass cover (~22%), woody basal area (~8 m2/ha), and woody canopy cover (31%), translating to a ~8.5 t/ha increase in aboveground carbon over two decades. Herbivore exclusion also led to a 54% increase (20.5 t/ha) in total soil carbon to 30‐cm depth, with ~71% of this derived from C4 grasses (vs. ~76% with herbivores present) despite substantial increases in woody cover. We attribute this continued high contribution of C4 grasses to soil C sequestration to the reduced offtake of grass biomass with herbivore exclusion together with the facilitative influence of open sparse woody canopies (e.g., Acacia spp.) on grass cover and productivity in this semiarid system. [ABSTRACT FROM AUTHOR]

We propose a methodology to leverage machine learning (ML) for the detection of web application vulnerabilities. We use it in the design of Mitch, the first ML solution for the black-box detection of cross-site request forgery vulnerabilities. Finally, we show the effectiveness of Mitch on real software. [ABSTRACT FROM AUTHOR]

In this paper, we propose using a decoupled architecture to create a microservice that can deliver scientific visualization remotely with efficiency, scalability, and superior availability, affordability and accessibility. Through our effort, we have created an open source platform, Tapestry, which can be deployed on Amazon AWS as a production use microservice. The applications we use to demonstrate the efficacy of the Tapestry microservice in this work are: (1) embedding interactive visualizations into lightweight web pages, (2) creating scientific visualization movies that are fully controllable by the viewers, (3) serving as a rendering engine for high-end displays such as power-walls, and (4) embedding data-intensive visualizations into augmented reality devices efficiently. In addition, we show results of an extensive performance study, and suggest how applications can make optimal use of microservices such as Tapestry. [ABSTRACT FROM AUTHOR]

Web-based DNNs provide accurate object recognition to the mobile Web AR, which is newly emerging as a lightweight mobile AR solution. Webbased DNNs are attracting a great deal of attention. However, balancing the UX against the computing cost for DNN-based object recognition on the Web is difficult for both self-contained and cloud-based offloading approaches, as it is a latency-sensitive service but also has high requirements in terms of computing and networking abilities. Fortunately, the emerging 5G networks promise not only bandwidth and latency improvement but also the pervasive deployment of edge servers which are closer to the users. In this article, we propose the first edge-based collaborative object recognition solution for mobile Web AR in the 5G era. First, we explore the finegrained and adaptive DNN partitioning for the collaboration between the cloud, the edge, and the mobile Web browser. Second, we propose a differentiated DNN computation scheduling approach specially designed for the edge platform. On one hand, performing part of DNN computations on mobile Web without decreasing the UX (i.e., keep response latency below a specific threshold) will effectively reduce the computing cost of the cloud system; on the other hand, performing the remaining DNN computations on the cloud (including remote and edge cloud) will also improve the inference latency and thus UX when compared to the self-contained solution. Obviously, our collaborative solution will balance the interests of both users and service providers. Experiments have been conducted in an actually deployed 5G trial network, and the results show the superiority of our proposed collaborative solution. [ABSTRACT FROM AUTHOR]

Web browsing is the main Internet service, and every customer wants the minimum web page loading times. To satisfy this perpetual need, web browsers offer new processing engines and increased functionalities. Web developers make use of new programming languages and paradigms, new transport protocols have been introduced, network operators offer increased bandwidth, and CDN providers deploy web servers closest to end users. To assess the efficiency of these evolutions, delivered performance is often evaluated in a standalone manner, without considering the whole chain of web browsing. We propose Web View, a measurement platform that performs automated web browsing sessions on popular websites in a user-representative environment. Through different configurable parameters, Web View measures a wide set of information in order to evaluate the impact of the different parameters (transport protocols, web browsers, CDN, access networks, etc.). Based on those measurements, to ease the understanding of web browsing and the corresponding evolutions, Web View offers a public visualization website (https://webview. orange.com). For instance, with Web View, we were able to detect that the use of different CDNs at different times of the day can decrease loading times up to 400 percent and that the delivery of content through different transport protocols can decrease loading times up to 79 percent. This article presents the Web View measurement platform as well as remarkable events we noticed during more than one year of measurements. [ABSTRACT FROM AUTHOR]

Traditional malicious attacks have evolved beyond file-based methods, with malicious files now existing as processes and services to evade detection. This article examines the rise of cryptojacking-the use of another's machine for profit through cryptocurrency mining-and how we're all at risk. [ABSTRACT FROM AUTHOR]

The transfer of terrestrial organic matter by terrestrial wild and domestic animals when they urinate and defecate directly in Savanna Rivers has already been studied. However, the eulittoral zone around waterholes receives organic matter during the dry season, which is diluted in the ecosystem when the waterholes returns to its wet season level. In our study, we evaluated this pathway of subsidies in Hwange National Park, Zimbabwe, by estimating dung density in the eulittoral zone at the peak of the dry season. We also collected dung from different herbivore species during the dry and wet seasons to measure nutrient content and estimate nitrogen and phosphorus leaching rates. Our results show a decrease in carbon:phosphorus and nitrogen:phosphorus ratios in the dry season compared to the wet season. During the dry season, the deposition of total carbon, nitrogen, and phosphorus, mostly due to elephants, is estimated to be 8.65, 0.25, and 0.06 g/m2/day, respectively, while the leaching rates of dissolved inorganic nitrogen and phosphorus are 1.52 mg and 6.59 mg m2/day, respectively. No specific coloured dissolved organic matter signature for dung was identified. We discuss the temporal dynamics of the subsidies as a distinctive feature of the system. [ABSTRACT FROM AUTHOR]

Online abuses give browser users an incentive to employ third-party cookie policies. These policies, built directly into the browser or provided through extensions, are intended to enhance the user's security and privacy. Unfortunately, virtually every policy can be bypassed. [ABSTRACT FROM AUTHOR]

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Colophospermum mopane, commonly known as mopane, produces secondary metabolites during the growing season. However, there is still insufficient knowledge on the quantity of secondary metabolites and the effect of browsers on the concentration of secondary metabolites. A pruning experiment was conducted in the Musina Nature Reserve, Limpopo province, South Africa, to simulate the effect of browsers on the concentration of secondary metabolites in mopane leaves. The twigs from 40 selected experimental mopane trees were pruned back 50 mm from their tips using a hand shear. The total amount of leaf and shoot biomass removed from branches of selected experimental trees was less than 10%. Three independent samples composed of seven mopane leaves per 40 mopane trees were randomly collected from the canopies of experimental and control trees per sampling event. The dried leaves from each three independent samples were then mixed separately and a pooled sample of 10 g per treatment per sample cycle (55 d) was used for determination of total phenols (TP), condensed tannins (CT) and protein-precipitating tannins (PPT). Results showed that <10% pruning does not have an effect on the amount of secondary metabolites in the mopane leaves. The concentration of TP, CT and PPT increased during leaf flush in October and then declined as the leaves matured and aged. It is concluded that the amount of secondary metabolites in mopane leaves is not dependent on <10% pruning, but appeared to be associated with leaf growth stages. The ability of mopane to produce secondary metabolites has implications on the seasonal diet composition and distribution of browsers in mopane woodland. [ABSTRACT FROM AUTHOR]

IPv6 measurement studies have focussed on measuring IPv6 adoption, while studies on measuring IPv6 performance have either become dated or only provide a snapshot view. We provide a longitudinal view of the performance of dual-stacked websites. We show that (since 2013) latency towards ALEXA 10K websites with AAAA entries over the six years have reduced by 29% over IPv4 and by 57% over IPv6. As of Dec 2018, 56% of these websites are faster over IPv6 with 95% of the rest being at most 1 ms slower. We also identify glitches in web content delivery that once fixed can help improve the user experience over IPv6. Using a publicly available dataset, we show that 40% of ALEXA 1M websites with AAAA entries were not accessible over IPv6 in 2009. These complete failures have reduced to 1.9% as of Jan 2019. However, our data collection on partial failures helps identify further that 27% of these popular websites with AAAA entries still suffer from partial failure over IPv6. These partial failures are affected by DNS resolution errors on images, javascript and CSS content. For 12% of these websites, more than half of the content belonging to same-origin sources fails over IPv6, while analytics and third-party advertisements contribute to failures from cross-origin sources. Our results also contribute to the IETF standardisation process. We witness that using an happy eyeballs timer value of 250 ms, clients prefer IPv6 connections to 99% of ALEXA 10 K websites (with AAAA entries) more than 96% of the time. Although, this makes clients prefer slower IPv6 connections in 81% of the cases. Our results show that a Happy Eyeballs (MBA) timer value of 150 ms does not severly affect IPv6 preference towards websites. The entire dataset presenting results on partial failures, latency and HE used in this paper is publicly released. [ABSTRACT FROM AUTHOR]

In order to avoid the "Midas Touch" problem, gaze-based interfaces for selection often introduce a dwell time: a fixed amount of time the user must fixate upon an object before it is selected. Past interfaces have used a uniform dwell time across all objects. Here, we propose a gaze-based browser using a two-step selection policy with variable dwell time. In the first step, a command (e.g., "back" or "select") is chosen from a menu using a dwell time that is constant across the different commands. In the second step, if the "select" command is chosen, the user selects a hyperlink using a dwell time that varies between different hyperlinks. We assign shorter dwell times to more likely hyperlinks and longer dwell times to less likely hyperlinks. In order to infer the likelihood each hyperlink will be selected, we have developed a probabilistic model of natural gaze behavior while surfing the web. We have evaluated a number of heuristic and probabilistic methods for varying the dwell times using both simulation and experiment. Our results demonstrate that varying dwell time improves the user experience in comparison with fixed dwell time, resulting in fewer errors and increased speed. While all of the methods for varying dwell time resulted in improved performance, the probabilistic models yielded much greater gains than the simple heuristics. The best performing model reduces error rate by 50% compared to 100ms uniform dwell time while maintaining a similar response time. It reduces response time by 60% compared to 300ms uniform dwell time while maintaining a similar error rate. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the accelerometer and gyroscope motion sensor-based cross-site input inference attacks that may compromise the security of many mobile Web users, and quantify the extent to which they can be effective. We formulate our attacks as a typical multi-class classification problem and build an inference framework that trains a classifier in the training phase and predicts the user’s new inputs in the attacking phase. To make our attacks effective and realistic, we design unique techniques and address major data quality and data segmentation challenges. We intensively evaluate the effectiveness of our attacks using 98 691 keystrokes collected from 20 participants. Overall, our attacks are effective, for example, they are about 10.8 times more effective than the random guessing attacks regarding inferring letters. We also perform experiments to evaluate the effect of using the data perturbation defense techniques on decreasing the accuracy of our input inference attacks. Our results demonstrate that researchers, smartphone vendors, and app developers should pay serious attention to the motion sensor-based cross-site input inference attacks that can be pervasively performed, and start to design and deploy effective defense techniques. [ABSTRACT FROM AUTHOR]

The last decade has seen innovations that make video recording, manipulation, storage, and sharing easier than ever before, thus impacting many areas of life. New video retrieval scenarios emerged as well, which challenge the state-of-the-art video retrieval approaches. Despite recent advances in content analysis, video retrieval can still benefit from involving the human user in the loop. We present our experience with a class of interactive video retrieval scenarios and our methodology to stimulate the evolution of new interactive video retrieval approaches. More specifically, the video browser showdown evaluation campaign is thoroughly analyzed, focusing on the years 2015–2017. Evaluation scenarios, objectives, and metrics are presented, complemented by the results of the annual evaluations. The results reveal promising interactive video retrieval techniques adopted by the most successful tools and confirm assumptions about the different complexity of various types of interactive retrieval scenarios. A comparison of the interactive retrieval tools with automatic approaches (including fully automatic and manual query formulation) participating in the TRECVID 2016 ad hoc video search task is discussed. Finally, based on the results of data analysis, a substantial revision of the evaluation methodology for the following years of the video browser showdown is provided. [ABSTRACT FROM AUTHOR]