Optimisation of work flow

AeroSpace Technologies of Australia (ASTA) is a supplier of aircraft components for several of the world's major aircraft manufacturers. Its anticipation of a substantial increase in demand has led to concern as to its ability to satisfy customer imposed schedules. ASTA's main concern is scheduling at its five autoclaves. The autoclaves, which are large pressurised ovens in which components are cured before non destructive testing and final assembly, appear to be the bottlenecks in ASTA's manufacturing process. ASTA came to the Australian Mathematics-in-Industry Study Group (MISG) with the objective of developing an optimised loading plan for the autoclaves to improve their utilisation while meeting demand for final components. This report discusses the results of an intensive three day study by the MISG group working on the ASTA problem. Its findings were that: • Modifying the way in which Materials Requirements Planning (MRP) is used may usefully increase autoclave utilisation. • A single product which will account for 60% of factory hours could and should be scheduled separately. • It is feasible and very helpful to group products into a small number of sets with common autoclave processing requirements. • Integer programming models modelling the production line show considerable promise and should be developed further

Building an Optimal Census of the Solar Neighborhood with Pan-STARRS Data

We estimate the fidelity of solar neighborhood (D < 100 pc) catalogs soon to be derived from Pan-STARRS astrometric data. We explore two quantities used to measure catalog quality: completeness, the fraction of desired sources included in a catalog; and reliability, the fraction of entries corresponding to desired sources. We show that the main challenge in identifying nearby objects with Pan-STARRS will be reliably distinguishing these objects from distant stars, which are vastly more numerous. We explore how joint cuts on proper motion and parallax will impact catalog reliability and completeness. Using synthesized astrometry catalogs, we derive optimum parallax and proper motion cuts to build a census of the solar neighborhood with the Pan-STARRS 3 Pi Survey. Depending on the Galactic latitude, a parallax cut pi / sigma pi > 5 combined with a proper motion cut ranging from mu / sigma mu > 1-8 achieves 99% reliability and 60% completeness.Comment: 7 Pages, 4 Figures, 3 Tables. PASP in pres

Simple approach to include external resistances in the Monte Carlo simulation of MESFETs and HEMTs

The contact and external series resistances play an important role in the performance of modern 0.1-0.2 μm HEMT's. It is not possible to include these resistances directly into the Monte Carlo simulations. Here we describe a simple and efficient way to include the external series resistances into the Monte Carlo results of the intrinsic device simulations. Examples of simulation results are given for a 0.2 μm pseudomorphic HEMT

The SoLid anti-neutrino detector's readout system

The SoLid collaboration have developed an intelligent readout system to reduce their 3200 silicon photomultiplier detector's data rate by a factor of 10000 whilst maintaining high efficiency for storing data from anti-neutrino interactions. The system employs an FPGA-level waveform characterisation to trigger on neutron signals. Following a trigger, data from a space time region of interest around the neutron will be read out using the IPbus protocol. In these proceedings the design of the readout system is explained and results showing the performance of a prototype version of the system are presented

Bounded analysis of constrained dynamical systems: a case study in nuclear arms control

We introduce a simple dynamical system that describes key features of a bilateral nuclear arms control regime. The evolution of each party's beliefs and declarations under the regime are represented, and the e ects of inspection processes are captured. Bounded analysis of this model allows us to explore { within a nite horizon { the consequences of changes to the rules of the arms control process and to the strategies of each party, bounded scope invariants for variables of interest, and dynamics for initial states containing strict uncertainty. Together these would potentially enable a decision support system to consider cases of interest irrespective of unknowns. We realize such abilities by building a Python package that draws on the capabilities of a Satis ability Modulo Theory (SMT) solver to explore particular scenarios and to optimize measures of interest { such as the belief of one nation in the statements made by another, or the timing of an unscheduled inspection such that it has maximum value. We show that these capabilities can in principle support the design or assessment of future bilateral arms control instruments by applying them to a set of representative and relevant test scenarios with realistic nite horizons

Locations of marine animals revealed by carbon isotopes

Knowing the distribution of marine animals is central to understanding climatic and other environmental influences on population ecology. This information has proven difficult to gain through capture-based methods biased by capture location. Here we show that marine location can be inferred from animal tissues. As the carbon isotope composition of animal tissues varies with sea surface temperature, marine location can be identified by matching time series of carbon isotopes measured in tissues to sea surface temperature records. Applying this technique to populations of Atlantic salmon (Salmo salar L.) produces isotopically-derived maps of oceanic feeding grounds, consistent with the current understanding of salmon migrations, that additionally reveal geographic segregation in feeding grounds between individual philopatric populations and age-classes. Carbon isotope ratios can be used to identify the location of open ocean feeding grounds for any pelagic animals for which tissue archives and matching records of sea surface temperature are available

Inferring introduction routes of invasive species using approximate Bayesian computation on microsatellite data

Determining the routes of introduction provides not only information about the history of an invasion process, but also information about the origin and construction of the genetic composition of the invading population. It remains difficult, however, to infer introduction routes from molecular data because of a lack of appropriate methods. We evaluate here the use of an approximate Bayesian computation (ABC) method for estimating the probabilities of introduction routes of invasive populations based on microsatellite data. We considered the crucial case of a single source population from which two invasive populations originated either serially from a single introduction event or from two independent introduction events. Using simulated datasets, we found that the method gave correct inferences and was robust to many erroneous beliefs. The method was also more efficient than traditional methods based on raw values of statistics such as assignment likelihood or pairwise F(ST). We illustrate some of the features of our ABC method, using real microsatellite datasets obtained for invasive populations of the western corn rootworm, Diabrotica virgifera virgifera. Most computations were performed with the DIYABC program (http://www1.montpellier.inra.fr/CBGP/diyabc/)