5,933 research outputs found
Ada education in a software life-cycle context
Some of the experience gained from a comprehensive educational program undertaken at The Charles Stark Draper Lab. to introduce the Ada language and to transition modern software engineering technology into the development of Ada and non-Ada applications is described. Initially, a core group, which included manager, engineers and programmers, received training in Ada. An Ada Office was established to assume the major responsibility for training, evaluation, acquisition and benchmarking of tools, and consultation on Ada projects. As a first step in this process, and in-house educational program was undertaken to introduce Ada to the Laboratory. Later, a software engineering course was added to the educational program as the need to address issues spanning the entire software life cycle became evident. Educational efforts to date are summarized, with an emphasis on the educational approach adopted. Finally, lessons learned in administering this program are addressed
P-n junctions formed in gallium antimonide
Vapor phase deposition process forms a heavily doped n-region on a melt-grown p-type gallium antimonide substrate. HCl transports gallium to the reaction zone, where it combines with antimony hydride and the dopant carrier, hydrogen telluride. Temperatures as low as 400 degrees C are required
Can high-frequency ultrasound predict metastatic lymph nodes in patients with invasive breast cancer?
Aim
To determine whether high-frequency ultrasound can predict the presence of metastatic axillary lymph nodes, with a high specificity and positive predictive value, in patients with invasive breast cancer. The clinical aim is to identify patients with axillary disease requiring surgery who would not normally, on clinical grounds, have an axillary dissection, so potentially improving outcome and survival rates.
Materials and methods
The ipsilateral and contralateral axillae of 42 consecutive patients with invasive breast cancer were scanned prior to treatment using a B-mode frequency of 13 MHz and a Power Doppler frequency of 7 MHz. The presence or absence of an echogenic centre for each lymph node detected was recorded, and measurements were also taken to determine the L/S ratio and the widest and narrowest part of the cortex. Power Doppler was also used to determine vascularity. The contralateral axilla was used as a control for each patient.
Results
In this study of patients with invasive breast cancer, ipsilateral lymph nodes with a cortical bulge ≥3 mm and/or at least two lymph nodes with absent echogenic centres indicated the presence of metastatic axillary lymph nodes (10 patients). The sensitivity and specificity were 52.6% and 100%, respectively, positive and negative predictive values were 100% and 71.9%, respectively, the P value was 0.001 and the Kappa score was 0.55.\ud
Conclusion
This would indicate that high-frequency ultrasound can be used to accurately predict metastatic lymph nodes in a proportion of patients with invasive breast cancer, which may alter patient management
Controlled substrate cooling improves reproducibility of vapor deposited semiconductor composites
Improved substrate holder preferentially provides more uniform substrate cooling and increases the proportion of vapor flowing over the substrate during growth. Nitrogen gas is constricted in the substrate holder to cool the substrate
Growth of single-crystal gallium nitride
Use of ultrahigh purity ammonia prevents oxygen contamination of GaN during growth, making it possible to grow the GaN at temperatures as high as 825 degrees C, at which point single crystal wafers are deposited on /0001/-oriented sapphire surfaces
Vapor Phase Growth Technique and System for Several III-V Compound Semiconductors Interim Scientific Report
Vapor phase crystal growth and preparation of gallium, indium, arsenic, phosphorous, and antimony alloy semiconductor material
Vapor phase growth technique and system for several 3-5 compound semiconductors Quarterly technical report
Single vapor phase growth system for preparing semiconductor material
Automatic organisation of retrieved images into a hierarchy
Image retrieval is of growing interest to both search engines and academic researchers with increased focus on both content-based and
caption-based approaches. Image search, however, is different from document retrieval: users often search a broader set of retrieved
images than they would examine returned web pages in a search engine. In this paper, we focus on a concept hierarchy generation
approach developed by Sanderson and Croft in 1999, which was used to organise retrieved images in a hierarchy automatically
generated from image captions. Thirty participants were recruited for the study. Each of them conducted two different kinds of
searching tasks within the system. Results indicated that the user retrieval performance in both interfaces of system is similar.
However, the majority of users preferred to use the concept hierarchy to complete their searching tasks and they were satisfied with
using the hierarchical menu to organize retrieved results, because the menu appeared to provide a useful summary to help users look
through the image results
Building a diversity featured search system by fusing existing tools
This paper describes our diversity featured retrieval system which are built for the task
of ImageCLEFPhoto 2008. Two existing tools are used: Solr and Carrot. We have
experimented with different settings of the system to see how the performance changes.
The results suggest that the system can indeed increase diversity of the retrieved results
and keep the precision about the same
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