Gesundheitsinformationen im Internet

Electronic Health (E-Health) increasingly strives to provide health information and services to healthcare stakeholders (e.g., insurances, physicians, hospital and patient alliances, self-help groups) via the Internet, and to actively involve patients in their care. One major chance for these participatory healthcare and patient-oriented approaches that integrate patients in healthcare are the phenomena and ideas associated with providing information and healthcare on the Internet. This paper examines the existing body of knowledge on online health information and explores the current state of research through a review of literature by classifying articles published between the last two decades in IS, BISE, and health domain-specific journals as well as a review of past and current BMBF-, DFG-, and EU-funded research projects in this field. The fundamental categories of the analysis represent the stakeholders in the healthcare sector, the connecting information flows, the information-transferring technological applications, as well as the categories of the TEMPEST model. Amongst others, the results show that most of the analyzed papers discuss conventional, transactional E-Health applications. Within the TEMPEST model the technological category has the largest share of all categories. Based on these findings, causes and future research fields are discussed.     

Experimental analysis of the dynamic noise behavior of a two-stage cylindrical gearbox

There are several objectives in the design phase of gears: Besides a sufficient load capacity and a high efficiency of the gearbox, the acoustic behavior has to be taken into account. For a single-stage gearbox, several research projects have been carried out regarding the improvement of the noise behavior. Because of the mutual interactions between the gear meshes at a multi-stage gearbox, the knowledge at single-stage gearboxes cannot be transferred without restrictions. In this report, experimental investigations are carried out on a two-stage test gearbox. The experimental tests are analyzed by means of the stiffness of the intermediate shaft and the number of teeth of the two gear stages. The noise generation process will be investigated by the measured signals along the machine acoustic noise generation process. First, the excitation behavior of the gear mesh is analyzed by the detected rotational acceleration using angular rotation measurement systems. Subsequently, the transfer path between the gear meshes is determined to evaluate the mutual interactions between source and receiver. Based on the results, a guideline will be provided which stage has to be focused during the design phase.     

RTS-MAC: A Relative Time Synchronization MAC Protocol for Low Duty Cycle Body Sensor Networks

Emerging applications in the medical field require body sensor networks to communicate in real-time in a very energy-efficient way. An example is the Artificial Accommodation System??a set of two small active medical implants aiming at restoring accommodation of the human eye??in which sensor data have to be exchanged continuously between both eyes. To achieve energy efficiency, it is essential to operate the radios with a very low duty cycle. Therefore, idle listening and general protocol overhead must be reduced as much as possible. In this paper, we present a relative time synchronization medium access control protocol (RTS-MAC), which keeps relative time synchronization between two or more sensor nodes in a very energy-efficient manner: RTS-MAC makes use of the periodic broadcast of regular data messages and exploits the inter-arrival times to predict future arrivals within tight boundaries. Thereby, no overhead is generated for synchronization purposes, and still, idle listening is reduced to a minimum, which solely depends on the short-term accuracy of the underlying clock systems. We implemented the proposed protocol using off-the-shelf components and employed the internal low-accuracy oscillators of the microcontrollers as clock sources. Thereby, we achieved very low duty cycles close to an ideal minimum. Further, our results indicate that through omitting external crystals in favor of a minimally larger battery, the battery life of a sensor node can be prolonged.     

Manufacturing‐induced surface contaminations

In the course of classical optics manufacturing glass components are in permanent direct contact with aqueous operating materials. Such contact leads to a certain absorption of water and hydrogenous compounds that may induce severe glass defects. In this contribution, absorption of hydrogen and other contaminants during grinding of glass was observed and qualitatively detected via laser‐induced breakdown spectroscopy. It is shown that hydrogen, calcium, magnesium, and carbon are implanted into the glass surface where the contaminant concentration increases over grinding time or contact time of the glass surface with water and the grinding tool, respectively. The contaminants hydrogen, calcium, and magnesium can be attributed to the water used as lubricant. In contrast, carbon most likely originates from wear debris of the used silicon carbide grinding pads. Several possible mechanisms that lead to such surface contamination of glasses during grinding – diffusion, accumulation in micro cracks as well as the formation of hydrated silica – are finally introduced.     

Data-driven parameterization of polymer electrolyte membrane fuel cell models via simultaneous local linear structured state space identification

In order to mitigate the degradation and prolong the lifetime of polymer electrolyte membrane fuel cells, advanced, model-based control strategies are becoming indispensable. Thereby, the availability of accurate yet computationally efficient fuel cell models is of crucial importance. Associated with this is the need to efficiently parameterize a given model to a concise and cost-effective experimental data set. A challenging task due to the large number of unknown parameters and the resulting complex optimization problem. In this work, a parameterization scheme based on the simultaneous estimation of multiple structured state space models, obtained by analytic linearization of a candidate fuel cell stack model, is proposed. These local linear models have the advantage of high computational efficiency, regaining the desired flexibility required for the typically iterative task of model parameterization. Due to the analytic derivation of the local linear models, the relation to the original parameters of the non-linear model is retained. Furthermore, the local linear models enable a straight-forward parameter significance and identifiability analysis with respect to experimental data. The proposed method is demonstrated using experimental data from a 30 kW commercial polymer electrolyte membrane fuel cell stack.     

Weighted fuzzy clustering for capability-driven service aggregation

Workflow design, mashup configuration, and composite service formation are examples where the capabilities of multiple simple services combined achieve a complex functionality. In this paper, we address the problem of limiting the number of required services that fulfill the required capabilities while exploiting the functional specialization of individual services. Our approach strikes a balance between finding one service that matches all required capabilities and having one service for each required capability. Specifically, we introduce a weighted fuzzy clustering algorithm that detects implicit service capability groups. The clustering algorithm considers capability importance and service fitness to support those capabilities. Evaluation based on a real-world data set successfully demonstrates the effectiveness of and applicability for service aggregation.