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Because of the need for electronics use at temperatures beyond 150°C, new high temperature interconnection technologies emerge, like silver sintering and copper wire bonding. In the project PROPOWER inverter modules with IGBTs and diodes mounted on DBC substrates were investigated as a prototype. Analyses were made to study the effects of the new interconnect technologies on fatigue failure. It is...
This paper addresses the problem of evaluating and estimating the mechanical robustness of footholds for legged robots in unstructured terrain. In contrast to approaches that rely on human expert knowledge or human defined criteria to identify appropriate footholds, our method uses the robot itself to assess whether a certain foothold is adequate or not. To this end, one of the robot's legs is employed...
Lead-free reflow soldering techniques applying AuSn as well as SnAg electroplated bumps were chosen for the evaluation of the flip-chip-bonding process for X-ray pixel detectors. Both solders can be used in pick-and-place processes with a subsequent batch reflow suitable for high-volume production. AuSn solder was selected because of its fluxless bondability, good wettability, and self-alignment process...
SLIP models are generally known as one of the best and simplest abstractions describing the spring-like leg behavior found in human and animal running, and have thus been subject to exhaustive investigation. To exploit these findings in real robots, we utilize an operational space controller that projects the behavior of the SLIP model onto the dynamics of an actual segmented robotic leg. Additionally,...
Near Field Communication (NFC) has become widely available on smart phones. It helps users to intuitively establish communication between local devices. Accessing devices such as public terminals raises several security concerns in terms of confidentiality and trust. To overcome this issue, NFC can be used to leverage the trusted-computing protocol of remote attestation. In this paper, we propose...
In the last few years RFID technology has become a major driver of various businesses like logistics, supply-chain management and access control. Many of these applications base on the successful implementation of security services on the RFID tag side but also on the reader side. In this paper we present an efficient tool for early prototype implementations of RFID applications. We show how the developed...
Finding the three-dimensional representation of all or a part of a scene from a single two dimensional image is a challenging task. In this paper we propose a method for identifying the pose and location of objects with circular protrusions in three dimensions from a single image and a 3d representation or model of the object of interest. To do this, we present a method for identifying ellipses and...
In the present study, we investigate a control strategy for hopping motions of an articulated leg that is driven by series elastic actuation. A highly compliant spring in the knee joint allows the exploitation of periodic energy storage but creates a major control challenge by severely limiting the bandwidth of closed-loop position or force control. This handicap is intensified by slow actuators,...
Microprocessors are the heart of the devices we rely on every day. However, their non-volatile memory, which often contains sensitive information, can be manipulated by ultraviolet (UV) irradiation. This paper gives practical results demonstrating that the non-volatile memory can be erased with UV light by investigating the effects of UV-Clight with a wavelength of 254 nm on four different depackaged...
In the last decade, many articles have been published that demonstrate the susceptibility of cryptographic devices against implementation attacks. Usually, such devices draw their energy from a contact-based power supply. This power-supply connection is often exploited to extract the secret key by applying fault-injection methods and power-analysis attacks. In this article, we present implementation...
Web-based management solutions have become an increasingly important and promising approach especially for small and embedded environments. This article presents the design and implementation of an embedded system that leverages the Web-based enterprise management (WBEM) solution. WBEM has been designed to manage large heterogeneous environments but has not yet been deployed on small and embedded...
The electronics industry has successfully transitioned to lead free soldering for computer and consumer products while in the automotive industry due to the very high reliability requirements this step is still in an ongoing process. In order to ensure or even to enhance the reliability of electronics the improvement of lead free solder joints based on Sn-Ag-Cu (SAC) solder has been the focus of many...
The reliability of automotive electronics depends a great deal on solder joints. After the WEEE and RoHS came into effect the new focus became lead-free solder pastes such as SnAg or SnAgCu (SAC). One approach to improve the thermal fatigue properties of these alloys is to add a third or fourth alloying element SAC + X. Until now, this was always done by metallurgical alloying, requiring special apparatuses,...
We present a fully operable security gateway prototype, integrating quantum key distribution and realised as a system-on-chip. It is implemented on a field-programmable gate array and provides a virtual private network with low latency and gigabit throughput. The seamless hard- and software integration of a quantum key distribution layer enables high key-update rates for the encryption modules. Hence,...
Crucial to an evolutionary algorithm's performance is its selection scheme. We mathematically investigate the relation between polynomial rank and probabilistic tournament methods which are (respectively) generalisations of the popular linear ranking and tournament selection schemes. We show that every probabilistic tournament is equivalent to a unique polynomial rank scheme. In fact, we derived explicit...
Lead free reflow soldering techniques applying AuSn as well as SnAg electroplated bumps were chosen for the evaluation of the flip chip bonding process for a x-ray pixel detector. Both can be used in pick & place processes with a subsequent batch reflow suitable for high volume production. AuSn solder was selected due to its fluxless bondability, the good wettability and the self-alignment process...
Capitalizing on advances in CMOS and MEMS technologies, microrobots have the potential to dramatically change many aspects of medicine by navigating bodily fluids to perform targeted diagnosis and therapy. Onboard energy storage and actuation is very difficult at the microscale, but externally applied magnetic fields provide an unparalleled means of wireless power and control. Recent results have...
Chronically implantable, wireless neural interfaces require biocompatible, long term stable, and high density integration of all functional sub-components. For this, the integration and interconnection concept of the wireless neural interface was proposed and interconnection materials and methods were investigated and characterized. The module consists of an electronics IC assembled to an electrode...
In order to reduce costs in packaging especially for optoelectronic devices technologies are desirable that enable precise assembly at low cost. A flip chip assembly approach is presented using the self-alignment mechanism in combination with mechanical stops. Besides eutectic AuSn20 solder (80 wt.-% Au, Tm = 280 degC) which is widely used in optoelectronics the eutectic SnAg3.5 solder (96.5wt.-%...
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