Drift-free magnetic equilibrium reconstruction using the response to plasma position modulation

Inductive magnetic sensors are widely used for plasma equilibrium reconstruction and control. However, their measurements involve electronic integration and can therefore experience drift leading to inaccurate plasma positioning. For this reason, we have studied an original drift-free approach to estimate the plasma equilibrium. The principle of this correction is based on modulation of the plasma position and current at three independent frequencies and analysing the modulated magnetic signals to provide additional estimation on the equilibrium. Using a plasma model based on current wires, the accuracy of such a method is assessed for Tore Supra in terms of the signal to noise ratio. The plasma position is recovered within a precision of 5 mm for a signal to noise ratio better than 80 dB. Applying our approach to dedicated experiments performed on the Tore Supra tokamak, we confirm the quality of the result and find that we can estimate the radial and vertical positions of the plasma to 1 mm with a one standard deviation confidence interval.     

the controversial history of the crystal skulls: a case study in interpretive drift

Abstract

In the nineteenth century, several skulls carved from rock crystal appeared in the holdings of European collectors. The provenance of the skulls was unknown and experts regarded them as pre-Columbian artifacts. In the twentieth century, two very different histories formed about these objects. Through testing and archival research, forensic experts and curators concluded that the skulls were created in the nineteenth century using European technology. Conversely, a community of skull enthusiasts believes the skulls are thousands of years old and function as a sort of esoteric computer. They believe that by communing with crystal skulls, it is possible to access records of ancient civilizations. The skull enthusiasts have strongly resisted the findings of experts. This article applies Tanya Luhrmann’s theory of “interpretive drift” to examine how the skull enthusiasts were able to construct and invest in a mythology surrounding these objects in only a few decades. This case study suggests that material objects can serve an important role in forming the types of magical worldviews outlined by Luhrmann.     

Concept drift and how to identify it

This paper studies concept drift over time. We first define the meaning of a concept in terms of intension, extension and label. Then we study concept drift over time using two theories: one based on concept identity and one based on concept morphing. A qualitative toolkit for analysing concept drift is proposed to detect concept shift and stability when concept identity is available, and concept split and strength of morphing chain if using the morphing theory. We apply our framework in four case-studies: a political vocabulary in SKOS, the DBpedia ontology in RDFS, the LKIF-Core ontology in OWL and a few biomedical ontologies in OBO. We describe ways of identifying interesting changes in the meaning of concept within given application contexts. These case-studies illustrate the feasibility of our framework in analysing concept drift in knowledge organisation schemas of varying expressiveness.     

The history of the country park, 1966–2005: Towards a renaissance?

The origins of the Country Park are examined and the implications of those origins are analysed. Country Parks are followed through to the present, including their enthusiastic sponsorship by the Countryside Commission, their role in local authority policy and practice, and the decline noted in the 1999 House of Commons Select Committee inquiry into Town and Country Parks. In the last two years, the Country Parks Network, administered by Green Space and funded by the government, has shown the tenacity of the Country Park, and there are encouraging signs from the Countryside Agency of renewed interest, and its hopes for a ‘Renaissance in Country Parks’. A summary of this period is also included, but an assessment of the effectiveness of its initiatives must wait for more time to pass.     

Increasing pattern recognition accuracy for chemical sensing by evolutionary based drift compensation

Artificial olfaction systems, which mimic human olfaction by using arrays of gas chemical sensors combined with pattern recognition methods, represent a potentially low-cost tool in many areas of industry such as perfumery, food and drink production, clinical diagnosis, health and safety, environmental monitoring and process control. However, successful applications of these systems are still largely limited to specialized laboratories. Sensor drift, i.e., the lack of a sensor’s stability over time, still limits real industrial setups. This paper presents and discusses an evolutionary based adaptive drift-correction method designed to work with state-of-the-art classification systems. The proposed approach exploits a cutting-edge evolutionary strategy to iteratively tweak the coefficients of a linear transformation which can transparently correct raw sensors’ measures thus mitigating the negative effects of the drift. The method learns the optimal correction strategy without the use of models or other hypotheses on the behavior of the physical chemical sensors.     

Coastal environment: EC‐cost 48 bioconversion projects and economic aspects

Seaweed has proved to be both a potential resource and a problem for coastal areas. In the framework of the European Communities, a scientific commission was created some 8 years ago, in order to address the matter of seaweed bioconversion in Europe. A book, recently published, represents a fair review and survey of seaweed as a resource in Europe. The matter of seaweed problems and expanded use is now under study in a new programme.

This paper traces back the development and growth of this inter‐European effort and also provides an overview of achievements.     

35MHz鉴频器的混合集成电路模块化设计

在用分离元器件设计的３５ＭＨｚ鉴频器的基础上，介绍了一种混合集成电路模块化设计方案，最后给出了实验测试结果，并与用分离元件设计的鉴频器做了比较。     

Transport properties of undoped Cd0.9Zn0.1Te grown by high pressure bridgman technique

The electron drift mobility of undoped Cd_0.9Zn_0.1Te grown by high-pressure Bridgman method is measured by a time-of-flight technique. The sample shows a room temperature mobility and mobility lifetime product of 950 cm²/Vs and 1.6 × 10⁻⁴cm²/V, respectively. The mobility increases monotonically with decreasing temperature to 3000 cm²/Vs at 100 K. The dominant scattering mechanism for the electron transport is discussed by comparing with the theoretical mobility obtained by iterative solution of the Boltzmann equation.     

具有外伸臂超高层结构的水平位移计算

以设置四道外伸臂超高层结构为例，探讨了带外伸臂超高层建筑结构的水平位移计算问题。导出了求解外伸臂约束弯矩的矩阵方程，在此基础上推导了求解顶点水平位移的计算公式，同时探讨了外伸臂抗弯刚度的计算问题。最后给出了算例，说明外伸臂的有效性和计算方法对工程设计的实用性。     

一种MAC漂移检测功能的实现与应用

提出一种MAC漂移检测功能，该功能对端口间的MAC漂移进行实时统计，并根据统计结果作出适当处理，可以有效解决这一问题，并在多种实用场景中发挥重要作用。