Analytical edge power loss at the lower hybrid resonance: ANTITER IV validation and application to ion cyclotron resonance heating systems

In the ion cyclotron range of frequency (ICRF), the presence of a lower hybrid (LH) resonance can appear in the edge of a tokamak plasma and lead to deleterious edge power depositions. An analytic formula for these losses is derived in the cold plasma approximation and for a slab geometry using an asymptotic approach and an analytical continuation near the LH resonance. The way to minimize these losses in a large machine like ITER is discussed. An internal verification between the power loss computed with the semi-analytical code ANTITER IV for ion cyclotron resonance heating (ICRH) and the analytic result is performed. This allows us to check the precision of the numerical integration of the singular set of cold plasma wave differential equations. The set of cold plasma equations used is general and can be applied in other parameters domain.

Acceleration-based disturbance compensation for elastic rack-and-pinion drives

Rack-and-pinion drives are mainly used for large machine tools and are often operated with indirect position control. Due to the lack of state information on the output side, this results in reduced accuracy regarding the table position. In addition, the system can only react inadequately to disturbances outside the control loop, meaning that often insufficient results can be achieved in typical application scenarios such as milling. To meet the increasing dynamic and accuracy requirements of the modern manufacturing industry, this paper presents a highly dynamic acceleration-based disturbance compensation method. For this purpose, the table acceleration is estimated using a dynamical model of the drive train and compared to the signal from an additional acceleration sensor attached to the machine table. Based on the resulting difference, an additional compensation torque is provided, which suppresses the disturbance in counterphase. The approach is tested experimentally on an open control platform with industrial drive components and the behavior is investigated based on compliance frequency responses and externally applied milling forces. At the same time, a standardized parametrization methodology is developed and the robustness is evaluated by varying table masses. In summary, a considerable improvement of the dynamic disturbance behavior can be achieved compared to the conventional system without compensator.

“[T]hat Monstrous Machine of his”: The Machine Metaphor in John Cleland’s Memoir of a Woman of Pleasure

John Cleland’s Memoir of a Woman of Pleasure (1748–49), commonly known as Fanny Hill, is regarded as the first pornographic novel in English literature. Its description of sexual activities is explicit but its language is not coarse. It employs a wide range of metaphors to refer to both sexual acts and genitalia and the metaphor used most frequently to refer to the penis is “the machine.” The machine metaphor will be the focus of this paper, which aims to argue that the machine metaphor carries two meanings. The first is the machine as one of military metaphors common in erotica since sexual acts have long been represented as battles. Female sexual pleasure, portrayed in this novel, depends on the state of being destroyed or conquered by a large machine. The second usage of the military metaphor suggests the strong affiliation between the penis and a hydraulic machine – the hydraulic penis—as this paper will call it. That is, female sexual pleasure is not only entwined with the state of being ruined but also with a fluid flow.

Research Status of Hydrostatic Bearing Technology in Machine Tool

Background: As the basis of mechanical manufacturing, large-scale machine tools are developing in the direction of improving processing accuracy, load-bearing capacity and rigidity. Hydrostatic thrust bearing, hydrostatic guide and hydrostatic ram are important components of large machine tools, with the continuous improvement of product accuracy requirements, the research on hydrostatic thrust bearing, hydrostatic guide and hydrostatic ram are more important. Objective: This paper introduces the current research on hydrostatic thrust bearing, hydrostatic guide and hydrostatic ram to express the importance of hydrostatic ram in improving the machining accuracy of machine tools. The study aims to lay a foundation for research and development of hydrostatic ram in the future. Methods: Firstly, the hydrostatic bearing technology is introduced. Secondly, the research status of hydrostatic thrust bearing, hydrostatic guide and hydrostatic ram are introduced to provide theoretical basis for improving the processing performance of rest ram. Result: Deformation compensation and thermal deformation compensation of hydrostatic ram have been studied more. Most of study focus on the accuracy of hydrostatic ram, but less on the bearing performance of hydrostatic ram. Conclusion: Breakthroughs have been made in the research on precision control and structural form of the hydrostatic bearing at home and abroad. Most scholars take the ram of Computer Numerically Control (CNC) boring and milling machines as the research object, but there are less research on the ram of vertical lathes. Therefore, the academic circle should pay more attention to the bearing performance of the hydrostatic ram of vertical lathes.

Störgrößenkompensation für Vorschubantriebe/Disturbance compensation for feed drives

Zahnstange-Ritzel-Antriebe werden überwiegend bei großen Werkzeugmaschinen eingesetzt und häufig mit indirekter Lageregelung betrieben. Hieraus resultiert eine geringe Positioniergenauigkeit und ein unzureichendes dynamisches Nachgiebigkeitsverhalten. Um den hohen Genauigkeitsanforderungen moderner Werkzeugmaschinen gerecht zu werden, wird in diesem Beitrag eine beschleunigungsbasierte Störgrößenkompensation vorgestellt. Experimentelle Ergebnisse belegen eine Verbesserung des Störverhaltens.   Rack-and-pinion drives are mainly used in large machine tools and controlled by indirect position control. This leads to low positioning accuracy as well as an insufficient dynamic compliance. To meet the high accuracy requirements of modern machine tools, this paper presents an acceleration-based disturbance compensation. Experimental results prove a considerable improvement of the disturbance behavior.

Falcon: Honest-Majority Maliciously Secure Framework for Private Deep Learning

We propose Falcon, an end-to-end 3-party protocol for efficient private training and inference of large machine learning models. Falcon presents four main advantages – (i) It is highly expressive with support for high capacity networks such as VGG16 (ii) it supports batch normalization which is important for training complex networks such as AlexNet (iii) Falcon guarantees security with abort against malicious adversaries, assuming an honest majority (iv) Lastly, Falcon presents new theoretical insights for protocol design that make it highly efficient and allow it to outperform existing secure deep learning solutions. Compared to prior art for private inference, we are about 8× faster than SecureNN (PETS’19) on average and comparable to ABY3 (CCS’18). We are about 16 − 200× more communication efficient than either of these. For private training, we are about 6× faster than SecureNN, 4.4× faster than ABY3 and about 2−60× more communication efficient. Our experiments in the WAN setting show that over large networks and datasets, compute operations dominate the overall latency of MPC, as opposed to the communication.