A problem in optimal search and stop

Problem in optimal search and sto

Designing an automated prototype tool for preservation quality metadata extraction for ingest into digital repository

We present a viable framework for the automated extraction of preservation quality metadata, which is adjusted to meet the needs of, ingest to digital repositories. It has three distinctive features: wide coverage, specialisation and emphasis on quality. Wide coverage is achieved through the use of a distributed system of tool repositories, which helps to implement it over a broad range of document object types. Specialisation is maintained through the selection of the most appropriate metadata extraction tool for each case based on the identification of the digital object genre. And quality is sustained by introducing control points at selected stages of the workflow of the system. The integration of these three features as components in the ingest of material into digital repositories is a defining step ahead in the current quest for improved management of digital resources

Prediction of the flow-field interference induced by the long-range laser velocimeter in the Ames 40- by 80-foot and the 80- by 120-foot wind tunnels

The predicted flow disturbances induced in the test sections of the Ames 40- by 80-Foot Wind Tunnels by the presence of the Long-Range Laser Velocimeter (LRLV) are presented. The predictions were made using a potential-flow paneling code to model the test section and the LRLV, and a calculation of the resulting flow field was made. The flow velocity and angularity were calculated at numerous locations in the flow field relative to the LRLV, and the results are presented

Design of a Multi-Moon Orbiter

The Multi-Moon Orbiter concept is introduced, wherein a single spacecraft orbits several moons of Jupiter, allowing long duration observations. The ΔV requirements for this mission can be low if ballistic captures and resonant gravity assists by Jupiter’s moons are used. For example, using only 22 m/s, a spacecraft initially injected in a jovian orbit can be directed into a capture orbit around Europa, orbiting both Callisto and Ganymede enroute. The time of flight for this preliminary trajectory is four years, but may be reduced by striking a compromise between fuel and time optimization during the inter-moon transfer phases

Application of dynamical systems theory to a very low energy transfer

We use lobe dynamics in the restricted three-body problem to design orbits with prescribed itineraries with respect to the resonance regions within a Hill’s region. The application we envision is the design of a low energy trajectory to orbit three of Jupiter’s moons using the patched three-body approximation (P3BA). We introduce the “switching region,” the P3BA analogue to the “sphere of influence.” Numerical results are given for the problem of finding the fastest trajectory from an initial region of phase space (escape orbits from moon A) to a target region (orbits captured by moon B) using small controls

Neonatal weight loss in breast and formula-fed infants

We have observed an increase in the number of breast fed babies presenting with dehydration and/or failure to thrive because of lactation failure and non-recognition of feeding problems. Recent reports1,2 support this experience and recommend monitoring of the weight of infants through the neonatal period. However, these reports acknowledge uncertainty as to what actually constitutes normal neonatal weight loss. Maisels and colleagues published two studies which have been quoted as giving guidance on normal loss. Both studies were designed primarily to study factors that influence breast milk jaundice. The first3 reported a mean weight loss of about 6% in 100 unselected well babies during the first 3 days. The subsequent study4 reported a mean weight loss of 6.86% in 186 infants. The timescale over which babies were weighed was not clearly indicated, although it may have only been 2-3 days. The sample was neither population based nor randomly selected, being largely preselected because of the presence of more pronounced jaundice. The distribution of data points for early neonatal weight loss are likely to be skewed, yet both studies reported the results as mean (SD). Owing to the design and method of data presentation, these studies cannot reliably inform the debate as to what constitutes the norm. Marchini and colleagues published reports also designed primarily to study other issues. One5 indicated a mean early weight loss of 5.7%. Measurements were recorded over a three day period, and no indication is given of the skewness of the data. Another study6 reported a median weight loss of about 6% recorded over a four day period. At least one baby lost > 15% of his/her birth weight during this time, but there is no clear information as to the frequency with which more extreme degrees of weight loss are observed