Disturbance decoupled observers for systems with unknown inputs

This note deals with the design of reduced-order disturbance decoupled scalar functional observers for linear systems with unknown inputs. Based on a parametric approach, existence conditions are derived and a design procedure for finding reduced-order scalar functional observers is given. The derived existence conditions are relaxed and the procedure can find first-order disturbance decoupled scalar functional observers for some cases where the number of unknown inputs is more than the number of outputs. Also, the observer matching condition, which is the necessary requirement for the design of state observers for linear systems with unknown inputs, is not required. Numerical examples are given to illustrate the attractiveness of the proposed design method.

Multi-agent based supply chain management with dynamic reconfiguration capability

Supply chain management (SCM) has received increased attention in a globally challenging environment as companies face the necessity to improve customer service and maximize profit. Therefore, dynamic reconfiguration capability is vital for supply chain management to respond to changing customer requirements and operating environments. On the other hand, for its flexible and autonomous characteristics, multi-agent systems are a viable technology for SCM, and have been widely applied in SCM. To this end, dynamic reconfiguration in agent-based SCM systems is proposed from autonomy oriented computing point of view. The performance of agent-based SCM with dynamic reconfiguration is evaluated under a modified TAC SCM scenario. With a dynamic reconfigurable SCM system, new products and processes can be introduced with considerably less expense and ramp-up time.

Functional observability and the design of minimum order linear functional observers

The design of a minimum-order linear functional observer for linear time-invariant systems has been an open problem for over four decades. This technical note provides a solution to this problem. The technical note also introduces the concept of Functional Observability/Detectability and shows that the well-known concept of Observability/Detectability is a special case of Functional Observability/Detectability.

Time-delay systems : design of delay-free and low-order observers

This note provides a comprehensive treatment on the design of functional observers for linear systems having a time-varying delay in the state variables. The designed observers possess attractive features of being low-order and delay-free and hence they are cost effective and easy to implement. Existence conditions are derived and a design procedure for finding low-order observers is given.

Automatic grain texture analysis using integral transforms

Tonewood for musical instruments is quarter-sawn and frequently quality-graded based on visual appearance, mechanical and acoustic properties. The assessment uses simple human (subjective) observation, and two ‘‘experts’’ can rate the same sample differently. This paper describes the application of integral transforms (Fourier and Radon) for automatic (objective) assessment of the visual appearance of 10 Sitka spruce (Picea sitchensis) sample images. This work considers surface classification on the basis of grain orientation, count, spacing, and evenness or uniformity.

Existence conditions for functional observability from an eigenspace perspective

Two theorems on conditions for nonexistence and for existence, of built functional observers, from an eigenspace perspective are presented and proved. One more theorem on Functional Observability in terms of constructed products of matrices A,C and L0 is also presented. This theorem provides an easy way to check Functional Observability before proceeding with the design of functional observers. The existence and the nonexistence theorems are used to unify previously reported theorems on Functional Observability by showing their equivalence. The connection between the concept of Functional Observability and the well known concept of State Observability is also presented.

Robust finite-horizon Kalman filtering for uncertain discrete-time systems

In this note, we propose a design for a robust finite-horizon Kalman filtering for discrete-time systems suffering from uncertainties in the modeling parameters and uncertainties in the observations process (missing measurements). The system parameter uncertainties are expected in the state, output and white noise covariance matrices. We find the upper-bound on the estimation error covariance and we minimize the proposed upper-bound.

High-pressure study of low-compressibility Ta2N

Room temperature synchrotron x-ray diffraction experiments were performed on nanocrystal Ta₂N in a diamond anvil cell to a pressure of 55.48 GPa. This nitride is a well-known kind of high-hardness material, and it is found to be highly incompressible. The structure is stable with no phase transitions observed in this pressure range. The zero-pressure bulk modulus and its pressure derivative at ambient pressure are B₀ = 360 ± 3 GPa, B₀' = 4, and in room conditions, the a and c parameters are 3.054 Å, 4.996 Å, respectively. The bulk modulus of Ta₂N is greater than those of TaC, ε-TaN, Cr₂N and MoN. The differences in bulk moduli might be due to the differences in structure and the cohesive energy among these phases.

The association between alcohol interventions and Dui incidents in Geelong, Victoria

Introduction and aims : Driving under the influence of alcohol is a major public health problem, every year affecting the lives of billions around the world - and not least in Australia. Since 2001, several Traffic Accident Commission (TAC), police, and community interventions have been implemented in Geelong, Australia to curb drink driving. The current paper aims to assess the impact of 13 alcohol interventions on drink-driving rates in the Geelong region of Australia. The interventions comprised seven TAC media campaigns, three Victoria Police operations, two community interventions targeting licensed premises, and the alcohol interlock program.

Method : This study examined two types of Victoria Police frequency data: Driving under the influence (DUI) offences, and roadside preliminary breath testing (PBT) rates. Multiple regressions were carried out to determine if any of the interventions were significantly associated with frequency fluctuations in the data.

Results : Of the 13 alcohol interventions examined, three TAC campaigns and one Victoria Police operation precipitated significant decreases in drink-driving rates, while another three TAC campaigns were associated with significant increases in drink-driving rates. Over one in five (22.5%) had recorded prior DUI offences.

Conclusions : The most promising approach to curbing DUI-rates in Geelong, appear to be through informative media campaigns which show people specific settings where they might become mildly intoxicated without being aware of it, such as TAC’s ‘Education 1’ campaign. However, there remains a worrying level of recidivist drink drivers in Geelong suggesting the need for tailored approaches.

Attributions of responsibility for motor vehicle accidents and post-injury outcomes.

 This thesis explored the relationship between attributions of responsibility for motor vehicle accidents and post-injury outcomes among a large sample of TAC clients. Results demonstrated that, despite similar levels of physical injury, people who attribute responsibility for accidents to other persons or circumstances experience poorer physical and mental health recovery in comparison to those who attribute responsibility to themselves.