Benchmarking the Utility of -event Differential Privacy Mechanisms – When Baselines Become Mighty Competitors

The -event framework is the current standard for ensuring differential privacy on continuously monitored data streams. Following the proposition of-event differential privacy, various mechanisms to implement the framework were proposed. Their comparability in empirical studies is vital for both practitioners to choose a suitable mechanism and researchers to identify current limitations and propose novel mechanisms. By conducting a literature survey, we observe that the results of existing studies are hardly comparable and partially intrinsically inconsistent. To this end, we formalize an empirical study of -event mechanisms by a four-tuple containing re-occurring elements found in our survey. We introduce requirements on these elements that ensure the comparability of experimental results. Moreover, we propose a benchmark that meets all requirements and establishes a new way to evaluate existing and newly proposed mechanisms. Conducting a large-scale empirical study, we gain valuable new insights into the strengths and weaknesses of existing mechanisms. An unexpected – yet explainable – result is a baseline supremacy, i.e., using one of the two baseline mechanisms is expected to deliver good or even the best utility. Finally, we provide guidelines for practitioners to select suitable mechanisms and improvement options for researchers to break the baseline supremacy

Scientific and Practical Understandings of Smart Cities

Cities are key agents in the transformation of energy systems, since the majority of the world population lives in cities and most energy is consumed in urban areas. In recent times, the concept of smart cities has raised the attention of both scientists and practitioners in different fields. Smart cities are envisioned to link different fields of action such as mobility; energy production, distribution, and consumption; buildings; governance and stakeholder processes; and urban planning. Information and communication technologies are seen as key to these interconnections. The overall goal of a smart city is to save energy and simultaneously to increase the quality of life for inhabitants. Although a broad variety of descriptions of smart cities have been developed, the concept itself appears to be rather fuzzy and hard to grasp. A clear-cut, common definition of smart cities is still lacking. The goal of this paper is to better understand what a smart city constitutes and what it means from the perspective of science, as well as from a practical point of view. In a thorough literature analysis, we identify different i) definitions, ii) approaches, iii) fields of actions and iv) technologies associated with smart cities. Our analysis is based on interdisciplinary scientific literature, as well as on practical documents (e.g. websites of pilot projects). In a subsequent step, we compare the different understandings of smart cities. In so doing, we focus on similarities and differences between scientific and practical approaches. In a final step, we identify opportunities and challenges arising from the identified similarities and differences. Recognising these challenges and potentials is of particular interest for so-called transdisciplinary research in urban development, where scientists and practitioners work closely together. Differences between science and practice might on the one hand inform research on smart cities concerning practical implications and experiences. On the other hand, they can also inform practitioners about scientific innovation in urban development (e.g. cloud computing assessing sensor data in real time)

Benchmarking the Utility of w-Event Differential Privacy Mechanisms: When Baselines Become Mighty Competitors

The w-event framework is the current standard for ensuring differential privacy on continuously monitored data streams. Following the proposition of w-event differential privacy, various mechanisms to implement the framework are proposed. Their comparability in empirical studies is vital for both practitioners to choose a suitable mechanism, and researchers to identify current limitations and propose novel mechanisms. By conducting a literature survey, we observe that the results of existing studies are hardly comparable and partially intrinsically inconsistent. To this end, we formalize an empirical study of w-event mechanisms by re-occurring elements found in our survey. We introduce requirements on these elements that ensure the comparability of experimental results. Moreover, we propose a benchmark that meets all requirements and establishes a new way to evaluate existing and newly proposed mechanisms. Conducting a large-scale empirical study, we gain valuable new insights into the strengths and weaknesses of existing mechanisms. An unexpected - yet explainable - result is a baseline supremacy, i.e., using one of the two baseline mechanisms is expected to deliver good or even the best utility. Finally, we provide guidelines for practitioners to select suitable mechanisms and improvement options for researchers

Transplantation of selected or transgenic blood stem cells – a future treatment for HIV/AIDS?

Interaction with the chemokine receptor, CCR5, is a necessary precondition for maintaining HIV-1 infection. Individuals with the CCR5-delta32 deletion who lack this receptor are highly resistant to infection by the most common forms of HIV-1. We recently reported on the successful transplantation in an HIV-1-positive patient of allogeneic stem cells homozygous for the CCR5-delta32 allele, which stopped viral replication for more than 27 months without antiretroviral therapy

FINEX: A Fast Index for Exact & Flexible Density-Based Clustering (Extended Version with Proofs)*

Density-based clustering aims to find groups of similar objects (i.e., clusters) in a given dataset. Applications include, e.g., process mining and anomaly detection. It comes with two user parameters ({\epsilon}, MinPts) that determine the clustering result, but are typically unknown in advance. Thus, users need to interactively test various settings until satisfying clusterings are found. However, existing solutions suffer from the following limitations: (a) Ineffective pruning of expensive neighborhood computations. (b) Approximate clustering, where objects are falsely labeled noise. (c) Restricted parameter tuning that is limited to {\epsilon} whereas MinPts is constant, which reduces the explorable clusterings. (d) Inflexibility in terms of applicable data types and distance functions. We propose FINEX, a linear-space index that overcomes these limitations. Our index provides exact clusterings and can be queried with either of the two parameters. FINEX avoids neighborhood computations where possible and reduces the complexities of the remaining computations by leveraging fundamental properties of density-based clusters. Hence, our solution is effcient and flexible regarding data types and distance functions. Moreover, FINEX respects the original and straightforward notion of density-based clustering. In our experiments on 12 large real-world datasets from various domains, FINEX frequently outperforms state-of-the-art techniques for exact clustering by orders of magnitude

Micro-solid oxide fuel cells: status, challenges, and chances

Abstract: Micro-solid oxide fuel cells (micro-SOFC) are predicted to be of high energy density and are potential power sources for portable electronic devices. A micro-SOFC system consists of a fuel cell comprising a positive electrode-electrolyte-negative electrode (i.e. PEN) element, a gas-processing unit, and a thermal system where processing is based on micro-electro-mechanical-systems fabrication techniques. A possible system approach is presented. The critical properties of the thin film materials used in the PEN membrane are discussed, and the unsolved subtasks related to micro-SOFC membrane development are pointed out. Such a micro-SOFC system approach seems feasible and offers a promising alternative to state-of-the-art batteries in portable electronics. Graphical abstract: Graphical Abstract tex

Reflexion, Begleitung, Austausch – Die Online-Plattform StudentBodies-AN1 zur Prävention von Magersucht

Internetbasierte Gesundheitsinterventionen (IGI) finden aufgrund ihrer Vorteile und Möglichkeiten eine zunehmende Verbreitung und sind zugleich ein innovatives Forschungsfeld. Sie ermöglichen eine schnelle und weite Verbreitung bei relativ geringen Kosten pro Teilnehmer/in. Die ortsunabhängige Zugänglichkeit der Gesundheitsangebote erleichtert die Versorgung auch im ländlichen Raum. Weitere Vorteile bestehen in der zeitlich unabhängigen Nutzung, die sich leicht in den individuellen Tagesablauf integrieren lässt, ebenso wie in der Wahrung der Anonymität der Nutzer/innen, die eine offene und ehrliche Auseinandersetzung mit potentiell schwierigen Themen in einer Gruppe erleichtern kann. Diese Erwartungen sind die logische Konsequenz von Befunden aus der Grundlagenforschung zu computervermittelter Kommunikation

Alternative elektronische Tierkennzeichnung

Das neue Tieridentifikationssystem Agro SAW IDENT wurde gemeinsam mit Industriepartnern entwickelt. Den Kern bilden piezoelektrische Kristalle mit aufgedampften Metallstrukturen, die den internationalen Tiercode darstellen. Zum Auslesen des Tiercodes werden akustische Oberflächenwellen (Surface Acoustic Wave = SAW) ohne jegliche Energiequelle genutzt. Die SAW-Codierung und der Charakter der Funkübertragung im Mikrowellenbereich um 2,4 GHz unterscheiden sich grundlegend von der üblichen Tieridentifikation im Niederfrequenzbereich bei 134 kHz. Die Vorteile der passiven SAW-Identifikation liegen in der höheren Lesereichweite bis zu 10 m und der sehr kurzen Identifikationsdauer unter 10 ms bei hoher Erkennungssicherheit. In vier Betrieben wurde an 1.652 Milchkühen die Funktionssicherheit untersucht

Micro-solid oxide fuel cells as power supply for small portable electronic equipment

Micro-solid oxide fuel cell (SOFC) systems are anticipated for powering small, portable electronic devices, such as laptop, personal digital assistant (PDA), medical and industrial accessories. It is predicted that micro-SOFC systems have a 2-4 higher energy density than Li-ion batteries [1]. However, literature mainly focuses on the fabrication and characterization of thin films and membranes for micro-SOFC systems [2-12]; the entire system approach is not yet studied in detail. We will therefore discuss in this paper the entire approach from the fabrication of thin films and membranes up to the complete system, including fuel processing, thermal management and integration