Porqpine: a peer-to-peer search engine

In this paper, we present a fully distributed and collaborative search engine for web pages: Porqpine. This system uses a novel query-based model and collaborative filtering techniques in order to obtain user-customized results. All knowledge about users and profiles is stored in each user node?s application. Overall the system is a multi-agent system that runs on the computers of the user community. The nodes interact in a peer-to-peer fashion in order to create a real distributed search engine where information is completely distributed among all the nodes in the network. Moreover, the system preserves the privacy of user queries and results by maintaining the anonymity of the queries? consumers and results? producers. The knowledge required by the system to work is implicitly caught through the monitoring of users actions, not only within the system?s interface but also within one of the most popular web browsers. Thus, users are not required to explicitly feed knowledge about their interests into the system since this process is done automatically. In this manner, users obtain the benefits of a personalized search engine just by installing the application on their computer. Porqpine does not intend to shun completely conventional centralized search engines but to complement them by issuing more accurate and personalized results.Postprint (published version

Public Health for the Internet φ Towards A New Grand Challenge for Information Management

Business incentives have brought us within a small factor of achieving the database community\u27s Grand Challenge set out in the Asilomar Report of 1998. This paper makes the case for a new, focused Grand Challenge: Public Health for the Internet. The goal of PHI (or φ) is to enable collectives of hosts on the Internet to jointly monitor and promote network health by sharing information on network conditions in a peer-to-peer fashion. We argue that this will be a positive effort for the research community for a variety of reasons, both in terms of its technical reach and its societal impact. This version of the φ vision is targeted at readers in the database research community, but the effort is clearly multidisciplinary. A more generalist version of this paper will be maintained at http://openphi.net

Supporting the workflow of archaeo-related sciences by providing storage, sharing, analysis, and retrieval methods

The recovery and analysis of material culture is the main focus of archaeo-related work. The corpus of findings like rest of buildings, artifacts, human burial remains, or faunal remains is excavated, described, categorized, and analyzed in projects all over the world. A huge amount of archaeo-related data is the basis for many analyses. The results of analyzing collected data make us learn about the past. All disciplines of archaeo-related sciences deal with similar challenges. The workflow of the disciplines is similar, however there are still differences in the nature of the data. These circumstances result in questions how to store, share, retrieve, and analyze these heterogeneous and distributed data. The contribution of this thesis is to support archaeologists and bioarchaeologists in their work by providing methods following the archaeo-related workflow which is split in five main parts. Therefore, the first part of this thesis describes the xBook framework that has been developed to gather and store archaeological data. It allows creating several database applications to provide necessary features for the archaeo-related context. The second part deals with methods to share information, collaborate with colleagues, and retrieve distributed data of cohesive archaeological contexts to bring together archaeo-related data. The third part addresses a dynamic framework for data analyses which features a flexible and easy to be used tool to support archaeologists and bioarchaeologists executing analyses on their data without any programming skills and without the necessity to get familiar with external technologies. The fourth part introduces an interactive tool to compare the temporal position of archaeological findings in form of a Harris Matrix with their spatial position as 2D and 3D site plan sketches by using the introduced data retrieval methods. Finally, the fifth part specifies an architecture for an information system which allows distributed and interdisciplinary data to be searched by using dynamic joins of results from heterogeneous data formats. This novel way of information retrieval enables scientists to cross-connect archaeological information with domain-extrinsic knowledge. However, the concept of this information system is not limited to the archaeo-related context. Other sciences could also benefit from this architecture.Die Wiederherstellung und Analyse von materieller Kultur ist der Schwerpunkt archäologischer Arbeit. Das Material von Funden wie Gebäudereste, Artefakte, menschliche Überreste aus Bestattungen oder tierische Reste wird in Projekten auf der ganzen Welt ausgegraben, beschrieben, kategorisiert und analysiert. Die große Anzahl an archäologischen Daten bildet die Grundlage für viele Analysen. Die Ergebnisse der Auswertung der gesammelten Daten gibt uns Aufschluss über die Vergangenheit. Alle Disziplinen der archäologischen Wissenschaften setzen sich mit ähnlichen Herausforderungen auseinander. Der Arbeitsablauf ist in den einzelnen Disziplinen ähnlich, jedoch gibt es aufgrund der Art der Daten Unterschiede. Das führt zu Fragestellungen, wie heterogene und verteilte Daten erfasst, geteilt, abgerufen und analysiert werden können. Diese Dissertation beschäftigt sich mit der Unterstützung von Archäologen und Bioarchäologen bei ihrer Arbeit, indem unterstützende Methoden bereitgestellt werden, die dem archäologischen Arbeitsablauf , der in fünf Schritte unterteilt ist, folgt. Der erste Teil dieser Arbeit beschreibt das xBook Framework, welches entwickelt wurde, um archäologische Daten zu erfassen und zu speichern. Es ermöglicht die Erstellung zahlreicher Datenbankanwendungen, um notwendige Funktionen für den archäologischen Kontext bereitzustellen. Der zweite Teil beschäftigt sich mit der Zusammentragung von archäologischen Daten und setzt sich mit Methoden zum Teilen von Informationen, Methoden zur Zusammenarbeit zwischen Kollegen und Methoden zum Abruf von verteilten, aber zusammenhängenden archäologischen Daten auseinander. Der dritte Teil stellt ein dynamisches Framework für Datenanalysen vor, welches ein flexibles und leicht zu bedienendes Tool bereitstellt, das Archäologen und Bioarchäologen in der Ausführung von Analysen ihrer Daten unterstützt, so dass weder Programmierkenntnisse noch die Einarbeitung in externe Technologien benötigt werden. Der vierte Teil führt ein interaktives Tool ein, mit dem – unter Verwendung der zuvor beschriebenen Methoden zur Datenabfrage – die zeitliche Position von archäologischen Funden in Form einer Harris Matrix mit ihrer räumlichen Position als 2D- und 3D-Lageplan verglichen werden kann. Abschließend spezifiziert der fünfte Teil eine Architektur für ein Informationssystem, das die Durchsuchung von verteilten und interdisziplinären Daten durch dynamische Joins von Suchergebnissen aus heterogenen Datenformaten ermöglicht. Diese neue Art an Informationsabfrage erlaubt Wissenschaftlern eine Querverbindung von archäologischen Informationen mit fachfremdem Wissen. Das Konzept für dieses Informationssystem ist jedoch nicht auf den archäologischen Kontext begrenzt. Auch andere wissenschaftliche Bereiche können von dieser Architektur profitieren

Towards Scalable Network Traffic Measurement With Sketches

Driven by the ever-increasing data volume through the Internet, the per-port speed of network devices reached 400 Gbps, and high-end switches are capable of processing 25.6 Tbps of network traffic. To improve the efficiency and security of the network, network traffic measurement becomes more important than ever. For fast and accurate traffic measurement, managing an accurate working set of active flows (WSAF) at line rates is a key challenge. WSAF is usually located in high-speed but expensive memories, such as TCAM or SRAM, and thus their capacity is quite limited. To scale up the per-flow measurement, we pursue three thrusts. In the first thrust, we propose to use In-DRAM WSAF and put a compact data structure (i.e., sketch) called FlowRegulator before WSAF to compensate for DRAM\u27s slow access time. Per our results, FlowRegulator can substantially reduce massive influxes to WSAF without compromising measurement accuracy. In the second thrust, we integrate our sketch into a network system and propose an SDN-based WLAN monitoring and management framework called RFlow+, which can overcome the limitations of existing traffic measurement solutions (e.g., OpenFlow and sFlow), such as a limited view, incomplete flow statistics, and poor trade-off between measurement accuracy and CPU/network overheads. In the third thrust, we introduce a novel sampling scheme to deal with the poor trade-off that is provided by the standard simple random sampling (SRS). Even though SRS has been widely used in practice because of its simplicity, it provides non-uniform sampling rates for different flows, because it samples packets over an aggregated data flow. Starting with a simple idea that independent per-flow packet sampling provides the most accurate estimation of each flow, we introduce a new concept of per-flow systematic sampling, aiming to provide the same sampling rate across all flows. In addition, we provide a concrete sampling method called SketchFlow, which approximates the idea of the per-flow systematic sampling using a sketch saturation event

Strategy and ritual in institutional encounters: a linguistic ethnography of weekly meetings in the British Embassy in Brussels

This study enters the closed and secluded community of a British embassy. It enters a cultural milieu, a setting where a group of self-identifying people with certain shared beliefs engage in a set of distinctive and mutually intelligible practices and tries to gain a more complete understanding of its norms, values and expectations. In particular, it investigates the role of the weekly gathering of Heads of Section as organizational ritual and symbol of collective experience, conveying cultural norms, interpretations and expectations. The work is essentially anthropologically-informed and inspired, while at the same time guided by a profound interest in and concern for language and communication. Apart from linguistics and anthropology, the study relies on and expands upon existing methods and views in a variety of other independently established disciplines. It draws on the sociological writings of Goffman, the philosophical work of Durkheim and Turner, the political ideas of Marx and Weber and many others

A Survey on the Evolution of Stream Processing Systems

Stream processing has been an active research field for more than 20 years, but it is now witnessing its prime time due to recent successful efforts by the research community and numerous worldwide open-source communities. This survey provides a comprehensive overview of fundamental aspects of stream processing systems and their evolution in the functional areas of out-of-order data management, state management, fault tolerance, high availability, load management, elasticity, and reconfiguration. We review noteworthy past research findings, outline the similarities and differences between early ('00-'10) and modern ('11-'18) streaming systems, and discuss recent trends and open problems.Comment: 34 pages, 15 figures, 5 table

Proceedings of the Salford Postgraduate Annual Research Conference (SPARC) 2011

These proceedings bring together a selection of papers from the 2011 Salford Postgraduate Annual Research Conference(SPARC). It includes papers from PhD students in the arts and social sciences, business, computing, science and engineering, education, environment, built environment and health sciences. Contributions from Salford researchers are published here alongside papers from students at the Universities of Anglia Ruskin, Birmingham City, Chester,De Montfort, Exeter, Leeds, Liverpool, Liverpool John Moores and Manchester

Managing Natural Resources Through Vulnerability Analysis: An Applied Case Study into Recreational Activities at Coral Reefs in Puerto Rico

The purpose of this dissertation is to add knowledge to coral reef management by designing and testing a methodology to assess the vulnerability of select coral reefs to diving and snorkeling recreational activities within La Cordillera Nature Reserve, Puerto Rico. Vulnerability research consists of three main components. This includes measuring exposure to the stressor, characterizing the sensitivity of the exposure, and characterizing the capacity to act. In the context of this research, exposure refers to the number of potentially harmful actions that recreational snorkelers inflict on coral reef ecosystems when they contact the reef and includes the number of individuals over the reef, the duration of time spent over the reef, and the depth of the coral in relation to the location of individuals. Sensitivity includes the qualities that make some corals experience more impact when exposed to the same stressor (the snorkeler and diver behavior) and include the morphology of the coral and the topography of the reef. Finally, adaptive actions in this case refer to decisions and actions taken by a variety of individuals within the tourism industry. This includes crew decisions about dive and snorkel trips, interactions with divers and snorkelers during trips, and the attitudes, knowledge, and beliefs of divers and snorkelers about coral reefs. Dive and snorkel data were collected between January 2011 and June 2014. My findings indicate that some reefs within La Cordillera Nature Reserve, Puerto Rico are vulnerable to snorkeling activities. Icacos Island reefs have a high exposure to contacts, most likely because of the depth of the coral in relationship to the snorkeler. Fin contacts were the most potentially damaging behavior. Topographic features of these reefs may lead to more contacts. The number of potentially damaging contacts for snorkelers was high, (0.28 contacts per minute) at La Cordillera Nature Reserve when compared to the only other location where snorkeler contact rates were observed (St. Lucia). When this frequency is multiplied by the number of visitor-minutes spent at reefs on a yearly basis, the scale of the problem can appear to be a significant factor in increasing vulnerability. Reefs within La Cordillera Nature Reserve are also vulnerable to scuba diving activities. Dive operator data analyzed found the average number of trips during both the peak and non-peak season was the same, 107 trips. The average number of divers per trip was nine. The dives lasted from 35 – 51 minutes with a mean of 45 minutes at an average depth of 50 feet. This averages to slightly more than 3,200 divers per year, which is below all of the other recommended carrying capacities in coral reef locations globally. While the average number of divers may be below carrying capacity, the contact rate for divers observed in La Cordillera Nature Reserve, was 0.5 contacts per diver per minute. This rate is five times higher than all but two other coral reef locations where research on number of contacts with reefs was conducted. Similar to other research, divers who use cameras while diving had significantly more contacts with the reef than non-camera users. The reefs at one of the main dive sites, Diablo Cay, had a high percentage of soft corals. The unpredictable movement of these corals can make it difficult for a diver to avoid a contact and may be a contributing factor to why the contact rate per minute is higher for divers in Puerto Rico. Coral reef related tourism and recreational activities rank among one of the most important industries in Puerto Rico by providing jobs, supporting local economies, increasing visitor knowledge of coral reefs, promoting pro-environmental values, and helping to create a conservation ethic. Healthy and resilient coral reef ecosystems are essential to the tourism industry, specifically scuba diving and snorkeling operations. Given the current and expected growth in tourism and marine recreational activities, the problem of recreationally-based damage to coral ecosystems will continue to grow. This dissertation can inform management decisions designed to mitigate the impacts that dive and snorkel tourism have on coral reef systems in order to decrease the overall vulnerability of these systems. Recommended measures can be implemented to reduce the vulnerability of the system which then can continue to provide benefits to those who depend on this economy for their livelihood and well-being. Specifically, actions that decrease exposure is a tangible possibility. Reducing contacts is one such measure. Actions to encourage pro-environmental behaviors at the reef include revising briefings that reinforce etiquette at the reef and social norms that empower snorkelers, non-certified divers, and certified divers to make a greater effort to not contact the reef. Crew members should consider the skill and perceptions of their guests, mooring use, in water supervision, interventions, attending best practices workshops, and emphasis on the content and delivery of coral reef etiquette messages. Such measures are important for reducing the vulnerability of coral reefs to recreational activities, conserving these ecosystems, and sustaining the tourism economy of Puerto Rico and beyond

Probe-based visual analysis of geospatial simulations

This work documents the design, development, refinement, and evaluation of probes as an interaction technique for expanding both the usefulness and usability of geospatial visualizations, specifically those of simulations. Existing applications that allow the visualization of, and interaction with, geospatial simulations and their results generally present views of the data that restrict the user to a single perspective. When zoomed out, local trends and anomalies become suppressed and lost; when zoomed in, spatial awareness and comparison between regions become limited. The probe-based interaction model integrates coordinated visualizations within individual probe interfaces, which depict the local data in user-defined regions-of-interest. It is especially useful when dealing with complex simulations or analyses where behavior in various localities differs from other localities and from the system as a whole. The technique has been incorporated into a number of geospatial simulations and visualization tools. In each of these applications, and in general, probe-based interaction enhances spatial awareness, improves inspection and comparison capabilities, expands the range of scopes, and facilitates collaboration among multiple users. The great freedom afforded to users in defining regions-of-interest can cause modifiable areal unit problems to affect the reliability of analyses without the user’s knowledge, leading to misleading results. However, by automatically alerting the user to these potential issues, and providing them tools to help adjust their selections, these unforeseen problems can be revealed, and even corrected

Provisions of Earth Observation data sources for use by a GIS content management system and online marketplace

The objective of this investigation was to provide PIKSEL with EO data sources. Several steps were followed to achieve this goal. The initial phase of the research involved the identification and compilation of EO data sources available. The selection process aimed to encompass a wide range of geospatial, environmental, and climatic data to cater to the diverse needs of the PIKSEL use cases and its users. Subsequently, the EO data available was subjected to an evaluation to determine its relevance to the specific application and objectives of the PIKSEL platform. This assessment considered factors such as data accuracy, spatial and temporal resolution and data format. Once the relevant EO data sources were identified, the next step involved a detailed analysis of the data downloading procedures associated with each source. Each provider often presents unique requirements, access protocols, and data delivery formats, necessitating a thorough understanding of the technical intricacies and obtaining the necessary credentials for data acquisition. To streamline and automate the data retrieval process, a custom Python script was developed for the specific case of the evolution of the coastline. Recognizing the importance of user experience, a user-friendly interface was designed to facilitate straightforward data management. The interface aims to simplify the process of accessing and querying, ensuring that users, irrespective of their technical expertise, can efficiently interact with the platform's resources. However, various hurdles were encountered during the project, including diverse data access procedures, lack of standardization among data channels, and challenges in obtaining and understanding Copernicus data. Despite these challenges, this work presents a valuable resource for non-programming experts seeking to manage EO data with ease. The work also explores future opportunities to expand the platform, integrate other Copernicus services, include diverse relevant sources, and implement the user interface on the PIKSEL website.Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats SosteniblesObjectius de Desenvolupament Sostenible::13 - Acció per al Clim