Fraunhofer Society

About: Fraunhofer Society is a government organization based out in Munich, Germany. It is known for research contribution in the topics: Laser & Silicon. The organization has 24736 authors who have published 40168 publications receiving 820894 citations.

Optimum SAR/GMTI Processing and Its Application to the Radar Satellite RADARSAT-2 for Traffic Monitoring

Abstract: This paper derives an optimum processing method for ground moving-target indication (GMTI) with a multichannel synthetic aperture radar (SAR) system. This method enables efficient detection of moving objects and accurate estimation of their parameters and does not require any knowledge of the street network. The processing is applied to data acquired with the Canadian RADARSAT-2 satellite. Results of the performed trial are compared with the expected GMTI performance of the radar in order to validate the theory.

Denial of service attacks targeting a SIP VoIP infrastructure: attack scenarios and prevention mechanisms

Abstract: In this article we address the issue of denial of service attacks targeting the hardware and software of voice over IP servers or by misusing specific signaling protocol features. As a signaling protocol we investigate here the session initiation protocol. In this context we mainly identify attacks based on exhaustion of the memory of VoIP servers, or attacks that incur high CPU load. We deliver an overview of different attack possibilities and explain some attacks in more detail, including attacks utilizing the DNS system and those targeting the parser. A major conclusion of the work is the knowledge that SIP provides a wide range of features that can be used to mount DoS attacks. Discovering these attacks is inherently difficult, as is the case with DoS attacks on other IP components. However, with adequate server design, efficient implementation, and appropriate hardware, the effects of a large portion of attacks can be reduced

A Short History of Cleaning Robots

Abstract: The definition of the desired functions and the design of an ultimate versatile personal robot is an ongoing debate. Meanwhile, however, precursors of this yet to evolve species are well on their way to become commercial products. Cleaning robots for public environments as well as for private households seem to be able to provide the breakthrough which the designers of non-industrial robot systems have long awaited. This survey describes a selection of 30 different cleaning robots, with the first developments reaching back more than 15 years. With a few exceptions we have focused on floor cleaning, in particular indoor floor cleaning. We describe a variety of scrubbing and vacuuming robots which were developed for this task. The described systems range from heavy, large, and expensive industrial cleaning vehicles to small-size, light-weight, low-cost household devices. The survey does not include, however, systems for cleaning facades of buildings, or windows, or production tools. Although not all of the 30 cleaning robots abovementioned have yet reached the state of commercial products, their number alone certainly reflects the expectations regarding the economic value associated with the automation of cleaning tasks. In Europe only the estimates for the market for cleaning services range up to the order of USd 100 billion per year. It is therefore not surprising that the cleaning industry and the manufacturers of cleaning devices are rather enthusiastic with respect to the automation of cleaning tasks using (semi-)autonomous mobile robot systems.

Implantation and explantation of a wireless epiretinal retina implant device: observations during the EPIRET3 prospective clinical trial.

Abstract: PURPOSE. Visual sensations in patients with blindness and retinal degenerations may be restored by electrical stimulation of retinal neurons with implantable microelectrode arrays. A prospective trial was initiated to evaluate the safety and efficacy of a wireless intraocular retinal implant (EPIRET3) in six volunteers with blindness and RP. METHODS. The implant is a remotely controlled, fully intraocular wireless device consisting of a receiver and a stimulator module. The stimulator is placed on the retinal surface. Data and energy are transmitted via an inductive link from outside the eye to the implant. Surgery included removal of the lens, vitrectomy, and implantation of the EPIRET3 device through a corneal incision. The clinical outcome after implantation and explantation of the device was determined. The implant was removed after 4 weeks, according to the study protocol. RESULTS. Implantation was successful in all six patients. While the anterior part was fixed with transscleral sutures, the stimulating foil was placed onto the posterior pole and fixed with retinal tacks. The implant was well tolerated, causing temporary moderate postoperative inflammation, whereas the position of the implant remained stable until surgical removal. In all cases explantation of the device was performed successfully. Adverse events were a sterile hypopyon effectively treated with steroids and antibiotics in one case and a retinal break in a second case during explantation requiring silicone oil surgery. CONCLUSIONS. The EPIRET3 system can be successfully implanted and explanted in patients with blindness and RP. The surgical steps are feasible, and the postoperative follow-up disclosed an acceptable range of adverse events.