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Hydrogen sulfide contributes to hypoxic inhibition of airway transepithelial sodium absorption
(2016)
We demonstrated previously that phosphocholine and phosphocholine-modified macromolecules efficiently inhibit ATP-dependent release of interleukin-1β from human and murine monocytes by a mechanism involving nicotinic acetylcholine receptors (nAChR). Interleukin-1β is a potent pro-inflammatory cytokine of innate immunity that plays pivotal roles in host defence. Control of interleukin-1β release is vital as excessively high systemic levels cause life threatening inflammatory diseases. In spite of its structural similarity to acetylcholine, there are no other reports on interactions of phosphocholine with nAChR. In this study, we demonstrate that phosphocholine inhibits ion-channel function of ATP receptor P2X7 in monocytic cells via nAChR containing α9 and α10 subunits. In stark contrast to choline, phosphocholine does not evoke ion current responses in Xenopus laevis oocytes, which heterologously express functional homomeric nAChR composed of α9 subunits or heteromeric receptors containing α9 and α10 subunits. Preincubation of these oocytes with phosphocholine, however, attenuated choline-induced ion current changes, suggesting that phosphocholine may act as a silent agonist. We conclude that phophocholine activates immuno-modulatory nAChR expressed by monocytes but does not stimulate canonical ionotropic receptor functions.
Hydrogen sulfide (H2S) is a well-known environmental chemical threat with an unpleasant smell of rotten eggs. Aside from the established toxic effects of high-dose H2S, research over the past decade revealed that cells endogenously produce small amounts of H2S with physiological functions. H2S has therefore been classified as a gasotransmitter. A major challenge for cells and tissues is the maintenance of low physiological concentrations of H2S in order to prevent potential toxicity. Epithelia of the respiratory and gastrointestinal tract are especially faced with this problem, since these barriers are predominantly exposed to exogenous H2S from environmental sources or sulfur-metabolising microbiota. In this paper, we review the cellular mechanisms by which epithelial cells maintain physiological, endogenous H2S concentrations. Furthermore, we suggest a concept by which epithelia use their electrolyte and liquid transport machinery as defence mechanisms in order to eliminate exogenous sources for potentially harmful H2S concentrations.
An exploratory study: Analysis of Serbian tourism market and identification of major market segments
(2016)
Currently, there are a lot of research activities dealing with gamma titanium aluminide (γ-TiAl) alloys as new materials for low pressure turbine (LPT) blades. Even though the scatter in mechanical properties of such intermetallic alloys is more distinctive as in conventional metallic alloys, stochastic investigations on γ -TiAl alloys are very rare. For this reason, we analyzed the scatter in static and dynamic mechanical properties of the cast alloy Ti-48Al-2Cr-2Nb. It was found that this alloy shows a size effect in strength which is less pronounced than the size effect of brittle materials. A weakest-link approach is enhanced for describing a scalable size effect under multiaxial stress states and implemented in a post processing tool for reliability analysis of real components. The presented approach is a first applicable reliability model for semi-brittle materials. The developed reliability tool was integrated into a multidisciplinary optimization of the geometry of a LPT blade. Some processes of the optimization were distributed in a wide area network, so that specialized tools for each discipline could be employed. The optimization results show that it is possible to increase the aerodynamic efficiency and the structural mechanics reliability at the same time, while ensuring the blade can be manufactured in an investment casting process.
Recent years have seen extensive adoption of domain generation algorithms (DGA) by modern botnets. The main goal is to generate a large number of domain names and then use a small subset for actual C&C communication. This makes DGAs very compelling for botmasters to harden the infrastructure of their botnets and make it resilient to blacklisting and attacks such as takedown efforts. While early DGAs were used as a backup communication mechanism, several new botnets use them as their primary communication method, making it extremely important to study DGAs in detail.
In this paper, we perform a comprehensive measurement study of the DGA landscape by analyzing 43 DGAbased malware families and variants. We also present a taxonomy for DGAs and use it to characterize and compare the properties of the studied families. By reimplementing the algorithms, we pre-compute all possible domains they generate, covering the majority of known and active DGAs. Then, we study the registration status of over 18 million DGA domains and show that corresponding malware families and related campaigns can be reliably identified by pre-computing future DGA domains. We also give insights into botmasters’ strategies regarding domain registration and identify several pitfalls in previous takedown efforts of DGA-based botnets. We will share the dataset for future research and will also provide a web service to check domains for potential DGA identity.
Helping Johnny to Analyze Malware: A Usability-Optimized Decompiler and Malware Analysis User Study
(2016)
This paper presents methods for the reduction and compression of meteorological data for web-based wind flow visualizations, which are tailored to the flow visualization technique. Flow data sets represent a large amount of data and are therefore not well suited for mobile networks with low data throughput rates and high latency. Using the mechanisms introduced in this paper, an efficient transfer of thinned out and compressed data can be achieved, while keeping the accuracy of the visualized information almost at the same quality level as for the original data.
Online media consumption is the main driving force for the recent growth of the Web. As especially realtime media is becoming more and more accessible from a wide range of devices, with contrasting screen resolutions, processing resources and network connectivity, a necessary requirement is providing users with a seamless multimedia experience at the best possible quality, henceforth being able to adapt to the specific device and network conditions. This paper introduces a novel approach for adaptive media streaming in the Web. Despite the pervasive pullbased designs based on HTTP, this paper builds upon a Web-native push-based approach by which both the communication and processing overheads are reduced significantly in comparison to the pull-based counterparts. In order to maintain these properties when enhancing the scheme by adaptation features, a server-side monitoring and control needs to be developed as a consequence. Such an adaptive push-based media streaming approach is intr oduced as main contribution of this work. Moreover, the obtained evaluation results provide the evidence that with an adaptive push-based media delivery, on the one hand, an equivalent quality of experience can be provided at lower costs than by adopting pull-based media streaming. On the other hand, an improved responsiveness in switching between quality levels can be obtained at no extra costs.
Application Programming Interfaces (APIs) are a vital link between software components as well as between software and developers. Security APIs deliver crucial functionalities for programmers who see themselves in the increasing need for integrating security services into their software products. The ignorant or incorrect use of Security APIs leads to critical security flaws, as has been revealed by recent security studies. One major reason for this is rooted in usability issues. API Usability research has been deriving recommendations for designing usable APIs in general. Facing the growing relevance of Security APIs, the question arises, whether the observed usability aspects in the general space are already sufficient enough for building usable Security APIs. The currently available findings in the API Usability domain are selective fragments only, though. This still emerging field has not produced a comprehensive model yet. As a consequence, a first contribution of this paper is such a model that provides a consolidated view on the current research coverage of API Usability. On this baseline, the paper continues by conducting an analysis of relevant security studies, which give insights on usability problems developers had, when using Security APIs. This analysis leads to a proposal of eleven specific usability characteristics relevant for Security APIs. These have to be followed up by usability studies in order to evaluate how Security APIs need to be designed in a usable way and which potential trade-offs have to be balanced.
Results from the EU-project iStoppFalls : feasibility, effectiveness, approach for fall prevention
(2016)
Autonomous mobile robots comprise of several hardware and software components. These components interact with each other continuously in order to achieve autonomity. Due to the complexity of such a task, a monumental responsibility is bestowed upon the developer to make sure that the robot is always operable. Hence, some means of detecting faults should be readily available. In this work, the aforementioned fault-detection system is a robotic black box (RBB) attached to the robot which acquires all the relevant measurements of the system that are needed to achieve a fault-free robot. Due to limited computational and memory resources on-board the RBB, a distributed diagnosis is proposed. That is, the fault diagnosis task (detection and isolation) is shared among an on-board component (the black box) and an off-board component (an external computer). The distribution of the diagnosis task allows for a non-intrusive method of detecting and diagnosing faults, in addition to the ability of remotely diagnosing a robot and potentially issuing a repair command. In addition to decomposing the diagnosis task and allowing remote diagnosability of the robot, another key feature of this work is the addition of expert human knowledge to aid in the fault detection process.
Domestic Robotics
(2016)
The aim of design science research (DSR) in information systems is the user-centred creation of IT-artifacts with regard to specific social environments. For culture research in the field, which is necessary for a proper localization of IT-artifacts, models and research approaches from social sciences usually are adopted. Descriptive dimension-based culture models most commonly are applied for this purpose, which assume culture being a national phenomenon and tend to reduce it to basic values. Such models are useful for investigations in behavioural culture research because it aims to isolate, describe and explain culture-specific attitudes and characteristics within a selected society. In contrast, with the necessity to deduce concrete decisions for artifact-design, research results from DSR need to go beyond this aim. As hypothesis, this contribution generally questions the applicability of such generic culture dimensions’ models for DSR and focuses on their theoretical foundation, which goes back to Hofstede’s conceptual Onion Model of Culture. The herein applied literature-based analysis confirms the hypothesis. Consequently, an alternative conceptual culture model is being introduced and discussed as theoretical foundation for culture research in DSR.
MOOCs in POM Education
(2016)
Basic demand from enterprises towards academic education: provide students not only methodological/theoretical knowledge, but also prepare them for the future tasks in the world of works! This contradicts academia’s focus on sustainably teaching basic principles. With the extra-curricular international online program erp4students, we successfully managed to bridge this "conflict-of-interest”.
In this paper, we introduce the international program erp4students as general example on how to successfully prepare university students for the world of works without having to give up the basic principle in higher education, i.e., to exclusively provide sustainable education. We start with introducing the basic concept and design of the program and provide information regarding the demographic development over the past decade and implemented quality assurance mechanisms. Subsequently, the scope and design of and hitherto achieved insights from the Learning Culture Survey are outlined. On the basis of found results, we finally discuss how erp4students can deal with possible culture-specific issues that latest might emerge when the program gets available for learners in the Asian context.
Job-related migration has been fostered across Europe balancing unemployment in one country with demands for employees in others. However, the numbers of early school leavers and university dropouts significantly increased in the hosting countries. We propose a higher measure of cultural sensitivity in education in order to prevent frustration. The Learning Culture Survey investigates learners’ expectations towards and perceptions of education on international level with the aim to make culture in the context of education better understandable. After a brief introduction, we subsume the steps taken during the past seven years and found results. Subsequently, we introduce a method for the determination of conflict potential, which bases on the understanding of culture as the level to which people within a society accept deviations from the usual. We close with demonstrating the usefulness of the data and insights from our Learning Culture Survey in the context of practical scenarios.
Background: Falls are common in older adults and can result in serious injuries. Due to demographic changes, falls and related healthcare costs are likely to increase over the next years. Participation and motivation of older adults in fall prevention measures remain a challenge. The iStoppFalls project developed an information and communication technology (ICT)-based system for older adults to use at home in order to reduce common fall risk factors such as impaired balance and muscle weakness. The system aims at increasing older adults’ motivation to participate in ICT-based fall prevention measures. This article reports on usability, user-experience and user-acceptance aspects affecting the use of the iStoppFalls system by older adults.
Methods: In the course of a 16-week international multicenter study, 153 community-dwelling older adults aged 65+ participated in the iStoppFalls randomized controlled trial, of which half used the system in their home to exercise and assess their risk of falling. During the study, 60 participants completed questionnaires regarding the usability, user experience and user acceptance of the iStoppFalls system. Usability was measured with the System Usability Scale (SUS). For user experience the Physical Activity Enjoyment Scale (PACES) was applied. User acceptance was assessed with the Dynamic Acceptance Model for the Re-evaluation of Technologies (DART). To collect more detailed data on usability, user experience and user acceptance, additional qualitative interviews and observations were conducted with participants.
Results: Participants evaluated the usability of the system with an overall score of 62 (Standard Deviation, SD 15.58) out of 100, which suggests good usability. Most users enjoyed the iStoppFalls games and assessments, as shown by the overall PACES score of 31 (SD 8.03). With a score of 0.87 (SD 0.26), user acceptance results showed that participants accepted the iStoppFalls system for use in their own home. Interview data suggested that certain factors such as motivation, complexity or graphical design were different for gender and age.
Conclusions: The results suggest that the iStoppFalls system has good usability, user experience and user acceptance. It will be important to take these along with factors such as motivation, gender and age into consideration when designing and further developing ICT-based fall prevention systems.
Within qualitative interviews we examine attitudes towards driverless cars in order to investigate new mobility services and explore the impact of such services on everyday mobility. We identified three main issues that we would like to discuss in the workshop: (I) Designing beyond a driver-centric approach; (II) Developing mobility services for cars which drive themselves; and (III) Exploring self-driving practices.
An analysis of sharing string objects with the Java Virtual Machine was conducted; they are the most used objects in Java programs and they are immutable - thus they are read-only and easily identified. While the results are promising, it is clear that sharing more objects would result in better performance. Automatic object selection for sharing is non-trivial, because in the current state only read-only objects can be shared. This attribute can not be easily determined during runtime by an algorithm; the developer on the other hand can. This thesis presents the development of an Application Programmer Interface (API) that allows programmers to use the Java Virtual Machine (JVM) internal sharing functionality. Furthermore, we present the usage of the sharing API. Open-source software was used as real-world test cases. Afterwards the evaluation shows that the ratio between memory savings and start-up time overhead is reasonable.
SpMV Runtime Improvements with Program Optimization Techniques on Different Abstraction Levels
(2016)
The multiplication of a sparse matrix with a dense vector is a performance critical computational kernel in many applications, especially in natural and engineering sciences. To speed up this operation, many optimization techniques have been developed in the past, mainly focusing on the data layout for the sparse matrix. Strongly related to the data layout is the program code for the multiplication. But even for a fixed data layout with an accommodated kernel, there are several alternatives for program optimizations. This paper discusses a spectrum of program optimization techniques on different abstraction layers for six different sparse matrix data format and kernels. At the one end of the spectrum, compiler options can be used that hide from the programmer all optimizations done by the compiler internally. On the other end of the spectrum, a multiplication kernel can be programmed that use highly sophisticated intrinsics on an assembler level that ask for a programmer with a deep understanding of processor architectures. These special instructions can be used to efficiently utilize hardware features in processors like vector units that have the potential to speed up sparse matrix computations. The paper compares the programming effort and required knowledge level for certain program optimizations in relation to the gained runtime improvements.
The Fifth International Conference on Advances in Vehicular Systems, Technologies and Applications (VEHICULAR 2016), held between November 13-17, 2016 - Barcelona, Spain, continued the inaugural event considering the state-of-the-art technologies for information dissemination in vehicle-to-vehicle and vehicle-to-infrastructure and focusing on advances in vehicular systems, technologies and applications.