Scalable Data Management in Mobile Environments: protocol design in MANETs and data management in mobile sensors

My presentation addressed with two areas of my current research interests: (1) Protocol design in Mobile Ad-hoc Networks, and (2) Sensor data management. It describes briefly the motivating challenges and our approach to dealing with them

Efficient Probabilistic Subsumption Checking for Content-Based Publish/Subscribe Systems

Abstract. Efficient subsumption checking, deciding whether a subscription or publication is covered by a set of previously defined subscriptions, is of paramount importance for publish/subscribe systems. It provides the core system functionality—matching of publications to subscriber needs expressed as subscriptions—and additionally, reduces the overall system load and generated traffic since the covered subscriptions are not propagated in distributed environments. As the subsumption problem was shown previously to be co-NP complete and existing solutions typically apply pairwise comparisons to detect the subsumption relationship, we propose a ‘Monte Carlo type ’ probabilistic algorithm for the general subsumption problem. It determines whether a publication/subscription is covered by a disjunction of subscriptions in O(k md), wherek is the number of subscriptions, m is the number of distinct attributes in subscriptions, and d is the number of tests performed to answer a subsumption question. The probability of error is problem-specific and typically very small, and sets an upper bound on d. Our experimental results show significant gains in term of subscription set reduction which has favorable impact on the overall system performance as it reduces the total computational costs and networking traffic. Furthermore, the expected theoretical bounds underestimate algorithm performance because it performs much better in practice due to introduced optimizations, and is adequate for fast forwarding of subscriptions in case of high subscription rate.

Modelling Heat Transfer and Pathogen Disinfection in a Biogas-Powered Self-Sanitizing Toilet

<p>The problem of inadequate sanitation in less developed countries has dire health consequences such as diarrheal diseases. A household-scale sanitation system consisting of an anaerobic digester, heat exchanger, and biogas-powered heater, was developed to provide a simple, potentially low cost and low carbon-footprint solution to this problem. A conceptual model was developed to predict the effectiveness of the heat sterilization system in reaching the appropriate temperatures to significantly inactivate pathogens such as E. coli, helminthe ova, and viruses. Lab experiments with a stainless steel heater and exchanger were used to establish model parameters and to verify the model. Though the model sometimes predicts higher or lower values than the experimental data, probably due to uncertainties in pathogen decay constants and in the different heat transfer coefficients, the model adequately predicts temperature across the heat exchanger and heater, and can provide a preliminary estimate of pathogen inactivation within the system. Both disinfection experiments showed the system reduces E. coli concentrations to below the WHO limit, which was predicted by the model.</p>Thesi

06431 Working Group Summary: Atomicity in Mobile Networks

We introduce different mobile network applications and show to which degree the concept of database transactions is required within the applications. We show properties of transaction processing and explain which properties are important for each of the mobile applications. Furthermore, we discuss open questions regarding transaction processing in mobile networks and identify open problems for further research

Distributed key man-agement in dynamic outsourced databases: A trie-based approach

Abstract The decision to outsource databases is strategic in many organizations due to the increasing costs of internally managing large volumes of information. The sensitive nature of this information raises the need for powerful mechanisms to protect it against unauthorized disclosure. Centralized encryption to access control at the data owner level has been proposed as one way of handling this issue. However, its prohibitive costs renders it impractical and inflexible. A distributed cryptographic approach has been suggested as a promising alternative, where keys are distributed to users on the basis of their assigned privileges. But in this case, key management becomes problematic in the face of frequent database updates and remains an open issue. In this paper, we present a novel approach based on Binary Tries 1 . By exploiting the intrinsic properties of these data structures, key management complexity, and thus its cost, is significantly reduced. Changes to the Binary Trie structure remain limited in the face of frequent updates. Preliminary experimental analysis demonstrates the validity and the effectiveness of our approach

Récuperation, caractérisation et étude électrochimique de MnO2 recyclé des piles usagées (Zn-MnO2)

The recovery of the manganese dioxide from the spent primary batteries (Zn-MnO2) is reported. Spent batteries were dismantled to separate the contained valuable metals of the cell electrodes in the form of black powder. MnO2 material was recycled by chemical precipitation. Treatment of this black powder with HCl (37%) and H2O2 (30%) with stirring at temperature 70°C for one hour, Manganese was recovered by precipitation. Important characteristics of the MnO2 recycled were investigated by X-ray diffraction spectroscopy (XRD), Thermo-gravimetric analysis (ATG), and electrochemical study of MnO2 in KOH 1M by using cyclic voltametry.La récupération  du dioxyde de manganèse des batteries primaires épuisées (Zn-MnO2) est signalée. Les piles usagées ont été démantelées pour séparer les métaux précieux contenus des électrodes sous forme de poudre noire. Le traitement de la poudre noire avec HCl (37%) et de H2O2 (30%) avec agitation à la température 70°C pendant une heure, de manganèse a été récupéré par précipitation. Des caractéristiques importantes du MnO2 recyclé ont été étudiées par spectroscopie de diffraction des rayons X (XRD), l'analyse thermogravimétrique (ATG) et étude électrochimique dans KOH 1 M en utilisant la voltamétrie cyclique

Fast Probabilistic Subsumption Checking for Publish/Subscribe Systems

Efficient subsumption checking, deciding whether a subscription or publication is subsumed (covered) by a set of previously defined subscriptions, is of paramount importance for publish/subscribe systems. It provides the core system functionality, and additionally, reduces the overall system load and generated traffic in distributed environments. As the deterministic solution was shown previously to be co-NP complete and existing solutions typically employ costly pairwise comparisons to detect the subsumption relationship, we propose a probabilistic algorithm for the general subsumption problem. It efficiently determines whether a publication/subscription is covered by a disjunction of subscriptions in $O(k~m~d)$, where $k$ is the number of subscriptions, $m$ is the number of distinct attributes in subscriptions, and $d$ is the number of tests performed to answer a subsumption question. The probability of error is problem specific and typically very small, and determines an upper bound on $d$ in polynomial time prior to the algorithm execution. Our experimental results demonstrate the algorithm performs even better in practice due to introduced optimizations, and is adequate for fast forwarding of publications/subscriptions, especially in resource scarce environments, e.g. sensor networks

LinkEHR-Ed: A multi-reference model archetype editor based on formal semantics

Purpose To develop a powerful archetype editing framework capable of handling multiple reference models and oriented towards the semantic description and standardization of legacy data. Methods The main prerequisite for implementing tools providing enhanced support for archetypes is the clear specification of archetype semantics. We propose a formalization of the definition section of archetypes based on types over tree-structured data. It covers the specialization of archetypes, the relationship between reference models and archetypes and conformance of data instances to archetypes. Results LinkEHR-Ed, a visual archetype editor based on the former formalization with advanced processing capabilities that supports multiple reference models, the editing and semantic validation of archetypes, the specification of mappings to data sources, and the automatic generation of data transformation scripts, is developed. Conclusions LinkEHR-Ed is a useful tool for building, processing and validating archetypes based on any reference model.This work was supported in part by the Spanish Ministry of Education and Science under grant TS12007-66S7S-C02; by the Generalitat Valenciana under grant APOSTD/2007/055 and by the program PAID-06-07 de la Universidad Politecnica de Valencia.Maldonado Segura, JA.; Moner Cano, D.; Boscá Tomás, D.; Fernandez Breis, JT.; Angulo Fernández, C.; Robles Viejo, M. (2009). LinkEHR-Ed: A multi-reference model archetype editor based on formal semantics. International Journal of Medical Informatics. 78(8):559-570. https://doi.org/10.1016/j.ijmedinf.2009.03.006S55957078

A design theory for e-service environments: The interoperability challenge

The delivery of e-services across organizational boundaries poses a number of issues in terms of design of inter-organizational systems that support service delivery effectively. In this context interoperability emerges as a mandatory requirement for the design of Information Technology (IT) platforms supporting collaborative e-service environments. In this paper we address this issue by presenting a design theory for IT platforms supporting e-services based on both a deep understanding of the interoperability concept and a design research approach. Through the analysis of a cooperation framework developed in the context of an EU funded project, we instantiate the theory by providing the concrete example of a solution addressing this design problem. © 2012 Springer-Verlag GmbH Berlin Heidelberg.The delivery of e-services across organizational boundaries poses a number of issues in terms of design of inter-organizational systems that support service delivery effectively. In this context interoperability emerges as a mandatory requirement for the design of Information Technology (IT) platforms supporting collaborative e-service environments. In this paper we address this issue by presenting a design theory for IT platforms supporting e-services based on both a deep understanding of the interoperability concept and a design research approach. Through the analysis of a cooperation framework developed in the context of an EU funded project, we instantiate the theory by providing the concrete example of a solution addressing this design problem. © 2012 Springer-Verlag GmbH Berlin Heidelberg.Monograph's chapter