2,268 research outputs found
Entwicklung eines Multifunktionsinstruments für die laparoskopische Chirurgie
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Chirurgische Eingriffe werden zunehmend minimul-invasiv durchgeführt, um die Belastung der Patienten durch die Operation zu verringern. Die Innovation der hier vorgestellten technischen Lösung besteht darin,dass die einzelnen Instrumente, die für verschiedene Operationsschritte erforderlich sind, in einem gemeinsamen Handgriff zusammengefasst und damit im Operationsfeld simultan und rasch austauschbar vorgehalten werden können. Durch die Verwendung von verschiedenen Aktuatoren erfolgt der Wechsel zwischen den integrierten Insimmenten automatisiert, so dass eine Einhandbedienung gewährleistet ist
Neural basis of somatosensory target detection independent of uncertainty, relevance, and reports
Research on somatosensory awareness has yielded highly diverse findings with putative neural correlates ranging from activity within somatosensory cortex to activation of widely distributed frontoparietal networks. Divergent results from previous studies may reside in cognitive processes that often coincide with stimulus awareness in experimental settings. To scrutinise the specific relevance of regions implied in the target detection network, we used functional magnetic resonance imaging (n = 27) on a novel somatosensory detection task that explicitly controls for stimulus uncertainty, behavioural relevance, overt reports, and motor responses. Using Bayesian Model Selection, we show that responses reflecting target detection are restricted to secondary somatosensory cortex, whereas activity in insular, cingulate, and motor regions is best explained in terms of stimulus uncertainty and overt reports. Our results emphasise the role of sensory-specific cortex for the emergence of perceptual awareness and dissect the contribution of the frontoparietal network to classical detection tasks
Neverlast: Towards the Design and Implementation of the NVM-based Everlasting Operating System
Novel non-volatile memory (NVM) technologies allow for the efficient implementation of \u27\u27intermittently-powered\u27\u27 smart dust and edge computing systems in a previously unfamiliar way. Operating with rough environmental conditions where power-supply failures occur often requires adjustments to all parts of the system. This leads to an inevitable trade-off in the design of operating systems -- the overhead of persisting the achieved computation progress over power failures is detrimental to the possible amount of progress with the available energy budgets. It is, therefore, crucial to minimize the overhead of ensuring persistence. This paper presents the case that persistence should be provided as an operating-system service to achieve everlasting operating capabilities. Triggered by power-failure interrupts, an implicit persistence service for the processor status of a process preserves progress on the CPU-instruction level. This interrupt only triggers if necessary so that no power-state polling is needed. We outline architectures for everlasting systems and discuss their benefits and drawbacks compared to existing approaches. Thereby, the operating system provides persistence as a service at run-time to the application, with minimal overhead. Our approach enables the separation of the application from energy-supply state estimation, as well as state-preserving logic for software and hardware components
Challenges in Annotation of useR Data for UbiquitOUs Systems: Results from the 1st ARDUOUS Workshop
Labelling user data is a central part of the design and evaluation of
pervasive systems that aim to support the user through situation-aware
reasoning. It is essential both in designing and training the system to
recognise and reason about the situation, either through the definition of a
suitable situation model in knowledge-driven applications, or through the
preparation of training data for learning tasks in data-driven models. Hence,
the quality of annotations can have a significant impact on the performance of
the derived systems. Labelling is also vital for validating and quantifying the
performance of applications. In particular, comparative evaluations require the
production of benchmark datasets based on high-quality and consistent
annotations. With pervasive systems relying increasingly on large datasets for
designing and testing models of users' activities, the process of data
labelling is becoming a major concern for the community. In this work we
present a qualitative and quantitative analysis of the challenges associated
with annotation of user data and possible strategies towards addressing these
challenges. The analysis was based on the data gathered during the 1st
International Workshop on Annotation of useR Data for UbiquitOUs Systems
(ARDUOUS) and consisted of brainstorming as well as annotation and
questionnaire data gathered during the talks, poster session, live annotation
session, and discussion session
Modern Concurrency Platforms Require Modern System-Call Techniques
Writing well-maintainable parallel programs
that efficiently utilize many processor cores is still a
significant challenge. Threads are hard to use, and so are
event-based schemes. Furthermore, threads are affected by
the blocking anomaly, that is, the loss of parallelism when
threads execute a blocking system call—often resulting
in low core utilization and unnecessarily high response
times. This paper introduces pseudo-blocking system calls
built upon modern asynchronous queue-based system-call
techniques (like Linux’s io_uring) circumventing the
blocking anomaly. They are similar to Go’s programming
model, where one develops against a blocking interface to
keep the code structure clean. However, instead of using
synchronous non-blocking system calls as the underlying
technique, our approach internally uses an asynchronous
queue-based interface. We further present a novel architec-
ture for concurrency platforms, like Cilk and Go, enabling
low latencies and high throughput via pseudo-blocking
system calls. Finally, we discuss future OS enhancements
that would improve our proposed architecture. We imple-
mented and evaluated a concurrency platform based on
the concept of pseudo-blocking system calls. Our platform
can outperform state-of-the-art systems like Go by 1.17 ×
in a file-content search benchmark. It is able to increase
the throughput of a echo-server benchmark by 4 % when
compared to Go, and by 17.8 % when compared to Rust’s
Tokio while improving the tail latency
A new simulation framework for soil-root interaction, evaporation, root growth, and solute transport
We have developed a general model concept and a flexible software framework for the description of plant-scale soil-root interaction processes including the essential fluid mechanical processes in the vadose zone. The model was developed in the framework of non-isothermal, multiphase, multicomponent flow and transport in porous media. The software is an extension of the open-source porous media flow and transport simulator DuMux to embedded mixed-dimensional coupled schemes. Our coupling concept allows us to describe all processes in a strongly coupled form and adapt the complexity of the governing equations in favor of either accuracy or computational efficiency. We have developed the necessary numerical tools to solve the strongly coupled nonlinear partial differential equation systems that arise with a locally mass conservative numerical scheme even in the context of evolving root architectures. We demonstrate the model concept and its features, discussing a virtual hydraulic lift experiment including evaporation, root tracer uptake on a locally refined grid, the simultaneous simulation of root growth and root water uptake, and an irrigation scenario comparing different models for flow in unsaturated soil. We have analyzed the impact of evaporation from soil on the soil water distribution around a single plant’s root system. Moreover, we have shown that locally refined grids around the root system increase computational efficiency while maintaining accuracy. Finally, we demonstrate that the assumptions behind the Richards equation may be violated under certain conditions
A new simulation framework for soil-root interaction, evaporation, root growth, and solute transport
We have developed a general model concept and a flexible software framework for the description of plant-scale soil-root interaction processes including the essential fluid mechanical processes in the vadose zone. The model was developed in the framework of non-isothermal, multiphase, multicomponent flow and transport in porous media. The software is an extension of the open-source porous media flow and transport simulator DuMux to embedded mixed-dimensional coupled schemes. Our coupling concept allows us to describe all processes in a strongly coupled form and adapt the complexity of the governing equations in favor of either accuracy or computational efficiency. We have developed the necessary numerical tools to solve the strongly coupled nonlinear partial differential equation systems that arise with a locally mass conservative numerical scheme even in the context of evolving root architectures. We demonstrate the model concept and its features, discussing a virtual hydraulic lift experiment including evaporation, root tracer uptake on a locally refined grid, the simultaneous simulation of root growth and root water uptake, and an irrigation scenario comparing different models for flow in unsaturated soil. We have analyzed the impact of evaporation from soil on the soil water distribution around a single plant’s root system. Moreover, we have shown that locally refined grids around the root system increase computational efficiency while maintaining accuracy. Finally, we demonstrate that the assumptions behind the Richards equation may be violated under certain conditions
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