Pedestrian counting has attracted much interest of the academic and industry communities for its widespread application in many real-world scenarios. While many recent studies have focused on computer vision-based solutions for the problem, the deployment of cameras brings up concerns about privacy invasion. This paper proposes a novel indoor pedestrian counting approach, based on footstep-induced structural vibration signals with piezoelectric sensors. The approach is privacy-protecting because no audio or video data is acquired. Our approach analyzes the space-differential features from the vibration signals caused by pedestrian footsteps and outputs the number of pedestrians. The proposed approach supports multiple pedestrians walking together with signal mixture. Moreover, it makes no requirement about the number of groups of walking people in the detection area. The experimental results show that the averaged F1-score of our approach is over 0.98, which is better than the vibration signal-based state-of-the-art methods.

Domain Name System (DNS) injection is a censorship method for blocking access to blacklisted domain names. The method uses deep packet inspection on all DNS queries passing through the network and injects spoofed responses. Compared with other blocking mechanisms, DNS injection impacts uninvolved third-parties if their traffic is routed through a censored network. In this paper, we look for large deployments of DNS injection, measured from vantage points outside of the censored networks. DNS injection is known to be used in China since it leaked unintentionally into foreign networks. We find that DNS injection is also used in Iran and can be observed by sending DNS queries to Iranian networks. In mid 2013, the Iranian DNS filter was temporarily suspended for some names, which correlated with media coverage of political debates in Iran about blocking social media. Spoofed responses from China and Iran can be detected passively by the IP address returned. We propose an algorithm to obtain these addresses remotely. After testing 255002 open resolvers outside of China, we determined that 6% are potentially affected by Chinese DNS injection when querying top-level domains outside of China. This is essentially the result of one top-level domain name server for which an anycast instance is hosted in China.

Massively multiplayer online games have become increasingly popular. However, their operation is costly, as game servers must be maintained. To reduce these costs, we aim at providing a communication engine to develop massively multiplayer online games based on a peer-to-peer system. In this paper we analyze the requirements of such a system and present an overview of our current work.

Setup and management of smart home systems is a complex task, and thus challenging for technically inexperienced users. We conducted a qualitative user study to evaluate whether an assistance system could empower users to make better and informed decisions regarding the selection of devices, their interoperability, the resulting set of features and their price. A group of 20 participants used our assistance app on a smartphone to configure a smart home while optimizing for features, interoperability, and the price-performance ratio. The results of our user study show that our assistance app can ease the problem of selecting useful devices and at the same time users become aware of new features resulting from the interoperation of selected devices. Furthermore, the assistance app can counteract the inherent interoperability problem between devices of different vendors or platforms. Finally, users are not only interested in individual device prices. They want to learn the cost of a certain feature set, including the cost of all devices necessary to realize this feature. Interestingly, none of the current smart home systems on the market offer a comparable assistance mechanism. Third-party solutions are not available either, because an assistance app requires meta data about features, interoperability, and usage of devices. This meta data is currently not available via APIs in state-of-the-art smart home systems and marketplaces. Therefore, we present a smart home architecture resulting from our research that can, among other benefits, provide the necessary meta data. Our research indicates that commercial smart home systems should invest more effort in user assistance to gain widespread adoption among technically inexperienced users. This in turn requires substantial changes to the meta data management in smart homes, because otherwise these assistance systems cannot be realized.

Locating physical devices and accessing their functionality in pervasive environments is strongly restricted by their locality. Since there are more and more devices available, waiting to serve users, a simple way is required to access, connect, and most important to locate them in the real world. In this paper we propose an approach to connect and access arbitrary devices by federating them related to their geographical location. This approach allows us to create context-aware federations of devices - the Internet of things