Open Access

Wireless sensor networks have found their way into a wide range of applications among which environmental monitoring systems have attracted increasing interests of researchers. The main challenges for the applications are scalability of the network size and energy efficiency of the spatially distributed motes. These devices are mostly battery-powered and spend most of their energy budget on the radio transceiver module. A so-called Wake-On-Radio (WOR) technology can be used to achieve a reasonable balance among power consumption, range, complexity and response time. In this paper, a novel design for integration of WOR into IEEE802.1.5.4 is presented, which flexibly allows trade-offs in energy consumption between sender and receiver station, between real-time capability and energy consumption. For identical behavior, the proposed scheme is significantly more efficient than other schemes, which were proposed in recent publications, while preserving backward compatibility with standard IEEE802.15.4 transceivers.

In the work at hand, we combine a Private Information Retrieval (PIR) protocol with Somewhat Homomorphic Encryption (SHE) and use Searchable Encryption (SE) with the objective to provide security and confidentiality features for a third party cloud security audit. During the auditing process, a third party auditor will act on behalf of a cloud service user to validate the security requirements performed by a cloud service provider. Our concrete contribution consists of developing a PIR protocol which is proceeding directly on a log database of encrypted data and allowing to retrieve a sum or a product of multiple encrypted elements. Subsequently, we concretely apply our new form of PIR protocol to a cloud audit use case where searchable encryption is employed to allow additional confidentiality requirements to the privacy of the user. Exemplarily we are considering and evaluating an audit of client accesses to a controlled resource provided by a cloud service provider.

Die Verwendung von Kameras als Messmittel für medizinische Anwendungen setzt deren präzise Kalibrierung voraus. Gängige Verfahren modellieren die Abbildungseigenschaften einer Kamera mittels perspektivischer Projektion und parametrisierter Funktionen zur Beschreibung von Linsenverzerrung. In den Randbereichen des Kamerabildes sind diese Modelle oft unzureichend. Außerdem bedingt die Verwendung starrer Kalibriermuster eine in der Regel kleine Anzahl an nicht gleichmäßig verteilten Punktkorrespondenzen zur Bestimmung der Modellparameter. In der vorliegenden Arbeit wird ein vollkommen neues und nicht auf Modellen basierendes Kalibrierverfahren vorgestellt, bei dem jedes Kamerapixel unabhängig von jedem anderen kalibriert wird.

Gamification implies the application of methods and design patterns from gaming to non-gaming areas like learning or working. We applied an existing gamification design to production processes in an organization which provides sheltered employment for impaired persons. In contrast to existing work, we investigated not only a short period but a complete workday to measure the effects on the work performance. The study indicates that gamification has (1) a negative effect on workers with considerable cognitive impairments, (2) no significant effect on workers with medium cognitive impairments and (3) a positive effect on workers with mild cognitive impairments.

In the age data digitalization, important applications of optics and photonics based sensors and technology lie in the field of biometrics and image processing. Protecting user data in a safe and secure way is an essential task in this area. However, traditional cryptographic protocols rely heavily on computer aided computation. Secure protocols which rely only on human interactions are usually simpler to understand. In many scenarios development of such protocols are also important for ease of implementation and deployment. Visual cryptography (VC) is an encryption technique on images (or text) in which decryption is done by human visual system. In this technique, an image is encrypted into number of pieces (known as shares). When the printed shares are physically superimposed together, the image can be decrypted with human vision. Modern digital watermarking technologies can be combined with VC for image copyright protection where the shares can be watermarks (small identification) embedded in the image. Similarly, VC can be used for improving security of biometric authentication. This paper presents about design and implementation of a practical laboratory experiment based on the concept of VC for a course in media engineering. Specifically, our contribution deals with integration of VC in different schemes for applications like digital watermarking and biometric authentication in the field of optics and photonics. We describe theoretical concepts and propose our infrastructure for the experiment. Finally, we will evaluate the learning outcome of the experiment, performed by the students. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.