Active temperature compensation for an accelerometer based angle measuring device

An angle measuring device using a high performance and very compact accelerometer provides a new and exciting method for producing highly compact and accurate angle measuring devices. Accelerometers are micro-machined and are able to measure acceleration to a very high accuracy. By using gravity as a reference these compact devices can also be used for measuring angles of rotation. The inherent problem with these devices is that their response characteristic changes with temperature which is detrimental to measurement accuracy. This paper describes an effective method to overcome this problem using a temperature sensor and intelligent software to compensate for this drift characteristic. In order to demonstrate the effectiveness of this work, experiments have been developed and conducted with the results and analysis provided at the end
of this paper for discussion.

A discussion on passive location discovery in emitter networks using angle-only measurements

In this paper we discuss the ghost node problem found when triangulation of 2 or more nodes is required. We present and discuss a simple algorithm, termed ABLE (Angle Based Location Estimation), that will position randomly placed emitters in a wireless sensor network using a mobile antenna array. The individual nodes in the network are relieved of the localization task by the mobile antenna system and require no modifications to account for location determination. Furthermore, no beacon nodes (i.e. nodes that know their own position) are required. We provide analysis that indicates a reasonably small number of measurements are required to guarantee the successful
localization of the emitting nodes and demonstrate our results through simulation.

Derivative actions as a mechanism for the protection of minority shareholders in China: a result of convergence or divergence

The protection of minority shareholders has become one of the key features of company law reform in many countries in recent years. Various mechanisms have been created to achieve this objective. Australia has introduced the statutory derivative action procedure mainly based on models drawn from Canada and New Zealand; this provision was inserted into the Corporations Act in March 2000. China has also adopted a similar mechanism – known as the shareholder representative action; this scheme was based upon China’s understanding of statutory derivative actions in Western countries. China’s derivative action mechanism is reflected in amendments to the 2005 PRC Company Law and 2005 Securities Law that both were passed on 27 October 2005 and came into effective on 1 January 2006. The development of statutory derivative actions in different countries demonstrates the interaction between forces of convergence and divergence in company law reforms. This article reviews different mechanisms adopted in the Chinese law for the protection of minority shareholders. It especially focuses on an analysis of the nature of the shareholder representative action and the procedures for its utilisation in China – the equivalent to Western countries’ derivative actions. In comparison with statutory derivative actions in Australia, this article argues that the concept of the shareholder representative action in China rests upon a misunderstanding of Western derivative actions; this has involved a compromise between the dire need to protect shareholders and the ambiguities of a weak court system. As a consequence, China’s reforms in this area are largely a tentative gesture and are therefore unlikely to be very effective.

Fuzzy terminal attitude guidance controller with angle only measurements

This paper introduces the concept of terminal attitude guidance as an alternative to precision guidance and uses fuzzy control ideas in designing a control strategy for a pursuer in countering a manoeuvreing target. The fuzzy controller uses only angle measurements in the control strategy and produces satisfactory results in comparison to the LQR or H∞ type guidance controllers, although they were addressed in a precision guidance context. Both 2D and 3D cases have been considered.

Passive angle measurement based localization consistency via geometric constraints

In this paper, we examine the geometric relations between various measured parameters and their corresponding errors in angle-measurement based emitter localization scenarios. We derive a geometric constraint formulating the relationship among the measurement errors in such a scenario. Using this constraint, we formulate the localization task as a constrained optimization problem that can be performed on the measurements in order to provide the optimal values such that the solution is consistent with the underlying geometry.

The generation of new high angle boundaries during the hot torsional deformation of aluminium

The crystallographic rotation field for deformation in torsion is such that it is possible for orientations close to stable orientations to rotate away from the stable orientation. A Taylor type model was used to demonstrate that this phenomenon has the potential to transform randomly generated low-angle boundaries into high-angle boundaries. After imposing an equivalent strain of 1.2, up to 40% of the simulated boundaries displayed a disorientation in excess of 15°. These high-angle boundaries were characterised by a disorientation axis close to parallel with the sample radial direction. A series of hot torsion tests was carried out on 1050 aluminium to seek evidence for boundaries formed by this mechanism. A number of deformation-induced high-angle boundaries were identified. Many of these boundaries showed disorientation axes and rotation senses similar to those seen in the simulations. Between 10% and 25% of all the high-angle boundary present in samples twisted to equivalent strains between 2 and 7 could be attributed to the present mechanism.

Review of applications of the Cutting Angle methods

The theory of abstract convexity provides us with the necessary tools for building accurate one-sided approximations of functions. Cutting angle methods have recently emerged as a tool for global optimization of families of abstract convex functions. Their applicability have been subsequently extended to other problems, such as scattered data interpolation. This paper reviews three different applications of cutting angle methods, namely global optimization, generation of nonuniform random variates and multivatiate interpolation.

Extended cutting angle method of global optimization

Methods of Lipschitz optimization allow one to find and confirm the global minimum of multivariate Lipschitz functions using a finite number of function evaluations. This paper extends the Cutting Angle method, in which the optimization problem is solved by building a sequence of piecewise linear underestimates of the objective function. We use a more flexible set of support functions, which yields a better underestimate of a Lipschitz objective function. An efficient algorithm for enumeration of all local minima of the underestimate is presented, along with the results of numerical experiments. One dimensional Pijavski-Shubert method arises as a special case of the proposed approach.

Femoral sulcus angle and increased patella facet cartilage volume in an osteoarthritic population

Objective
The patellofemoral joint is an example of an incongruent articulation commonly affected by osteoarthritis (OA). The relationship between femoral sulcus angle and the development and progression of patellofemoral OA is unclear. The aim of this study was to examine the relationship between the femoral sulcus angle at baseline and patella cartilage volume at baseline and at 2-year follow-up among community based adults with established knee OA.

Methods
One hundred subjects had magnetic resonance imaging of their symptomatic knee at baseline and at 2-year follow-up. From these images, patella cartilage volume was determined. Radiographic skyline views of the patellofemoral joint were taken at baseline to measure the femoral sulcus angle.

Results
For every 1° increase in the femoral sulcus angle (i.e., as the sulcus angle became more shallow) there was an associated 9.1 mm3 (95% CI 3.1, 15.0) increase in medial patella cartilage volume at baseline (P = 0.003). There was a similar trend that approached statistical significance between the femoral sulcus angle and the lateral patella facet cartilage volume at baseline (P = 0.09). There was no association between the femoral sulcus angle at baseline and the change in patella cartilage volume over 2 years in either patellofemoral compartment.

Conclusion
These results infer that the femoral sulcus angle is a cross-sectional determinant of the amount of patella cartilage, but is not a major determinant of the annual change of patella cartilage volume among people with knee OA. These data suggest that a shallower sulcus in the context of established OA may be an advantageous anatomical variant. Further longitudinal studies are required to determine the role of the femoral sulcus angle in OA.

In situ observation of the aggregated morphology and interaction of dialkyldimethylammonium bromide with DNA at air/water interface by Brewster angle microscopy

The adsorption of DNA on the Langmuir film of a cationic surfactant, dioctadecyldimethylammonium bromide (DODA·Br), and the change of the aggregation morphology of the composite monolayer with respect to surface pressure have been investigated by Brewster angle microscopy (BAM). In contrast with the case of DODA·Br on pure water subphase, when DNA was dispersed into subphase, its adsorption to the interface monolayer through electrostatic interaction decreases the charge density and therefore promotes the formation of domain at low surface pressure. In addition, the electrostatic interaction changed the phase morphology of DODA·Br Langmuir monolayer under different surface pressure, that is, from flower-shaped crystalline domain on the pure water subphase to circular domain on the subphase dispersed with DNA. The result also shows that the monolayer of the composite at air/water interface under the high pressure is not homogeneous, but consists of incompletely fused domains. For the Langmuir film of the surfactant with shorter alkyl-chains, similar morphology can be observed both under the high and low surface pressure. But the tight-stacked circular domain is no longer observed.

Investigation of the postcure reaction and surface energy of epoxy resins using time-of-flight secondary ion mass spectrometry and contact-angle measurements

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to investigate correlations between the molecular changes and postcuring reaction on the surface of a diglycidyl ether of bisphenol A and diglycidylether of bisphenol F based epoxy resin cured with two different amine-based hardeners. The aim of this work was to present a proof of concept that ToF-SIMS has the ability to provide information regarding the reaction steps, path, and mechanism for organic reactions in general and for epoxy resin curing and postcuring reactions in particular. Contact-angle measurements were taken for the cured and postcured epoxy resins to correlate changes in the surface energy with the molecular structure of the surface. Principal components analysis (PCA) of the ToFSIMS positive spectra explained the variance in the molecular information, which was related to the resin curing and postcuring reactions with different hardeners and to the surface energy values. The first principal component captured information related to the chemical phenomena of the curing reaction path, branching, and network density based on changes in the relative ion density of the aliphatic hydrocarbon and the C₇H₇O⁺ positive ions. The second principal component captured information related to the difference in the surface energy, which was correlated to the difference in the relative intensity of the C_xH_yN_z⁺ ions of the samples. PCA of the negative spectra provided insight into the extent of consumption of the hardener molecules in the curing and postcuring reactions of both systems based on the relative ion intensity of the nitrogen-containing negative ions and showed molecular correlations with the sample surface energy.