Planning, visualisation and intraoperative navigation in a robot assisted environment for craniofacial surgery require highly accurate methods for the segmentation of bone structures in CT data. Clinical systems are s...
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ISBN:
(纸本)1586030140
Planning, visualisation and intraoperative navigation in a robot assisted environment for craniofacial surgery require highly accurate methods for the segmentation of bone structures in CT data. Clinical systems are still based on time consuming interactive methods like the seed-point segmentation. Faster methods with no need for interactivity lacks in precision. In the following we will present an automatic and highly accurate algorithm for the segmentation of bone contours in CT data. It is based on an algorithm for the automatic calculation of a grey-value tissue relation model for CT and MRI data.
We present the concept of a system architecture for the computer aided craniofacial surgery. The architecture is based on CORBA, an industrial standard specification for the development of distributed applications. Ou...
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ISBN:
(纸本)1586030140
We present the concept of a system architecture for the computer aided craniofacial surgery. The architecture is based on CORBA, an industrial standard specification for the development of distributed applications. Our concept includes a fundamental behaviour oriented communication model and some fundamental software safety considerations. We've developed a standard library for the integration of new services and devices into our system architecture. It decreases development time noticeably. We tested the performance and usability of our concept on an evaluation set up consisting of a surgery robot system, an infrared navigation system, a force-torque sensor and a visualisation software, obtaining excellent results. Future work will consist in the integration of further devices and the extension of our safety concept. An accurate clinical evaluation will take place continuously.
This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a m...
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This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a micro-controller or system-on-a-chip. Handling of external real-time events is performed through multithreading. Real-time threads are used as interrupt service threads (ISTs) instead of interrupt service routines (ISRs). Our proposed micro-controller supports multiple ISTs with zero-cycle context switching overhead. We investigate the behavior of fixed priority preemptive, earliest deadline first, least laxity first and guaranteed percentage scheduling with respect to multithreaded processors. Our finding is that the strategies GP and LLF result in a good blending of instructions of different threads thus enabling a multithreaded processor to utilize latencies best. Assuming a zero-cycle context switch LLF performs best, however implementation cost context, are prohibitive.
We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Re...
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We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as interrupt service threads (ISTs) instead of interrupt service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
Currently, most commercial robot manipulators are equipped with conventional PID controllers due to their simplicity in structure and ease of design. Using such a controller, however, it is difficult to achieve a desi...
Currently, most commercial robot manipulators are equipped with conventional PID controllers due to their simplicity in structure and ease of design. Using such a controller, however, it is difficult to achieve a desired control performance since the dynamic equations of a mechanical manipulator are tightly coupled. In addition, they are highly nonlinear and uncertain. This paper uses a new hybrid control scheme to control a direct drive two-link manipulator under inertial parameters changes. The proposed hybrid control scheme consists of a fuzzy logic proportional controller and a conventional integral and derivative controller (FUZZY P+ID). In comparison with a conventional PID controller, only one additional parameter has to be adjusted to tune the FUZZY P+ID controller. The outlined experimental results demonstrate the effectiveness and the robustness of the new FUZZY P+ID controller.
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