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This paper discusses the requirements of current and emerging applications based on the Open Archives Initiative (OAI) and emphasizes the need for a common infrastructure to support them. Inspired by HTTP proxy, cache, gateway and web service concepts, a design for a scalable and reliable infrastructure that aims at satisfying these requirements is presented. Moreover it is shown how various applications can exploit the services included in the proposed infrastructure. The paper concludes by discussing the current status of several prototype implementations., Comment: 20 pages, 6 figures

As the semiconductor industry accelerates the pace of change, a shift in exposure wavelength from 248 nm to 193 nm becomes inevitable. Correspondingly, the change to a shorter wavelength and the desire to maintain productivity, necessitates a fundamental reassessment of system design approach. Evaluation of resolution and k-factor for a lithographic tool operating at 193 nm and 0.75 numerical aperture indicates that 130 nm node production will be manageable with binary mask, and that performance consistent with 100 nm node requirements and potentially beyond will be achievable with the use of advanced lithographic techniques. This paper reviews the design, system performance analysis and early results for a full-field catadioptric lithography tool operating at numerical apertures up to 0.75 NA.

The never ending drive for faster and denser ICS has reached a staggering pace is attributable to the economics of the semiconductor industry and competition among chip manufacturers. This quest may be approached in different ways. A common approach is to continue to push the 248nm wavelength lithographic tools. This paper reviews the status of 193nm lithography with respect to its production worthiness, capability and extendibility when compared to 248nm systems. Key issues such as cost of ownership and process maturity are discussed. Analytical results, system analyses and recent lithographic results are presented. Conclusions are offered with respect to the logical timing of the insertion of 193nm lithography tools into semiconductor manufacturing.

A meeting was held in Santa Fe, New Mexico, October 21--22, 1999, to generate discussion and consensus about interoperability of publicly available scholarly information archives. The invitees represented several well known e-print and report archive initiatives, as well as organizations with interests in digital libraries and the transformation of scholarly communication. The central goal of the meeting was to agree on recommendations that would make the creation of end-user services--such as scientific search engines and linking systems--for data originating from distributed and dissimilar archives easier. The Universal Preprint Service (UPS) Prototype was developed in preparation for this meeting. As a proof-of-concept of a multi-discipline digital library of publicly available scholarly material, the Prototype harvested nearly 200,000 records from several different archives and created an attractive end-user environment. This paper describes the results of the project. This is done in two ways. On the one hand, the experimental end-user service that was created during the project is illustrated. On the other hand, the lessons that the project team drew from the experience of creating the Prototype are presented.

This paper presents a path planning algorithm that is part of the STESCA control architecture for autonomous vehicles. The path planning algorithm models an autonomous vehicle's path as a series of line segments in Cartesian space and compares each line segment to a list of known obstacles and hazardous areas to determine if any collisions or hindrances exist. In the event of a detected collision, the algorithm selects a point outside the obstacle or hazardous area, generates two new path segments that avoid the obstruction and recursively checks the new paths for other collisions. Once underway, if the autonomous vehicle encounters previously unknown obstacles or hazardous areas, the path planner operates in a run-time mode that decides how to re-route the path around the obstacle or abort. This paper describes the path planner along with examples of path planning in a two-dimensional environment with a wheeled land-based robotic vehicle.

The Strategic-Tactical-Execution Software Control Architecture (STESCA) is a tri-level approach to controlling autonomous vehicles. Using an object-oriented approach, STESCA has been developed as a generalization of the Rational Behavior Model (RBM). STESCA was initially implemented for the Phoenix Autonomous Underwater Vehicle (Naval Postgraduate School -- Monterey, CA), and is currently being implemented for the Pioneer AT land-based wheeled vehicle. The goals of STESCA are twofold. First is to create a generic framework to simplify the process of creating a software control architecture for autonomous vehicles of any type. Second is to allow for mission specification system by 'anyone' with minimal training to control the overall vehicle functionality. This paper describes the prototype implementation of STESCA for the Pioneer AT.

This book provides a practical guide to the understanding, interpretation, and application of the principles of nutritional epidemiology, set in the context of public health nutrition. Relating dietary and nutritional exposures to health outcomes requires a rigorous approach to measurement of both the key exposure and outcome variables of interest and also the associated measurement errors. Moreover, the analysis of such data requires appropriate statistical approaches that take into account sampling, measurement techniques, and the role of confounders in the context of specific study designs. The first part of the book brings a practical focus to the scientific concepts underlying study design with emphasis on design, planning, and evaluation of nutritional epidemiological studies; issues of sampling, sample size and power; and an understanding of the impact of measurement error, with practical remedies. The second part deals with the problems of measurement and interpretation of a variety of variables relevant to nutritional epidemiology. It covers issues relating to determination of food consumption and nutrient intake and the strengths and weaknesses of approaches to such measurements; the strengths and weaknesses of biochemical markers as indicators of both nutrient intake and nutritional status; validation studies of dietary assessment; and assessment of the potential influence of socio-economic factors, anthropometric measurements, and gene-nutrient interactions on diet-health associations. The final part addresses the principles and interpretation of the main types of epidemiological study in the context of questions addressing relationships between diet and health, including issues of lag time and relevant exposure.

Fifty-one male and female volunteers aged 18–90 years from a wide variety of social and occupational backgrounds completed 7284 assessments of portion size in relation to food photographs. Subjects were shown six portion sizes (two small, two medium and two large) for each of six foods, and asked to compare the amount on the plate in front of them to (a) a series of eight photographs showing weights of portions from the 5th to the 95th centile of portion size (British Adult Dietary Survey), or (b) a single photograph of the average (median) portion size. Photographs were prepared either in colour or in black and white, and in two different sizes. The order of presentation of foods; use of black and white or colour; the size of photographs; and presentation of eight or average photographs were each randomized independently. On average, the mean differences between the portion size presented and the estimate of portion size using the photographs varied from -8 to + 6g (-4 to + 5%) for the series of eight photographs, and from -34 to −1g (-23 to + 9%) for the single average photograph. Large portion sizes tended to be underestimated more than medium or small portion sizes, especially when using the average photograph (from -79 to -14g, -37 to -13%). Being female, 65 years and over, or retired, or seeing photographs in colour, were all associated with small but statistically significant overestimations of portion size. Having a body mass index ≥ 30 kg/m2 was associated with an 8% underestimate of portion size. We conclude that use of a series of eight photographs is associated with relatively small errors in portion size perception, whereas use of an average photograph is consistently associated with substantial underestimation across a variety of foods.

One hundred and fourteen 11–14-year-old schoolgirls from Wembley, Middlesex, were assessed for Fe status (haemoglobin (Hb), packed cell volume and mean corpuscular Hb concentration, height, weight eating habits, and ethnic origin, and undertook a step test to assess physical performance. Overall, 20% of girls had Hb less than 120 g/l, ranging from 11 % in White girls to 22–25% in girls of Asian origin. Prevalence of low Hb was 20% in vegetarians, higher in White vegetarians compared with non-vegetarians (23 v. 4%), but lower in the Indian vegetarians compared with non-vegetarians (17 v. 32%). Low Hb was present in 25 % of girls who had tried to lose weight in the previous year, and was more common in girls from manual social class backgrounds than non-manual (24 v. 10%). At the start of the step test the twenty-three girls with low Hb had heart rates similar to those with normal Hb, but hear rates in the low Hb group were significantly elevated immediately after the step test, and still significantly elevated 1 min later. The present results confirm the findings of a previous study in White girls, and suggest that physical performance may be compromised at mild levels of anaemia.

years, there is still considerable doubt concerning the validity of this relationship in the UK (and, by implication, in other Western countries in which diets are by and large seen to be adequate). There is no question that intelligence and academic performance are affected by nutritional status; evidence abounds from studies in undernourished children (Pollitt, 1990) and adults (Passmore

This paper presents considerations about several topics that have a direct influence on data reliability and performance in object oriented database management systems. These topics are: physical storage management (clustering), concurrency control, crash recovery, garbage collection, and database security. Each topic is illustrated by its application to the Tactical Database as designed for the Low Cost Combat Direction System.

To date, there is no design methodology that is universally accepted by the object-oriented community. Several such methodologies, however, have been proposed. They are all somewhat similar in their approach to identifying and defining the objects and in organizing them into class hierarchies. The methodology proposed in this paper is the result of a research project in object-oriented design, and benefited from the experience acquired during the design of the Tactical Database for the Low Cost Direction System.

Children (227), aged 7–12 years, weighed and recorded all food and drink consumed for seven consecutive days. Each child completed tests of verbal and non-verbal intelligence, and was then randomly allocated to one of two groups after matching for age, sex, IQ and height. In a double-blind trial lasting for 28 d, one group received a vitamin-mineral supplement daily and the other group a placebo. On re-testing, there were no significant differences in performance between the two groups. Furthermore, there were no consistent correlations between test scores and micronutrient intakes based on the weighed records. Thus, we found no evidence that learning ability in a cross-section of British schoolchildren was limited by the quality of their diets.

Like many new ideas, object oriented programming (OOP) does not yet have a universally accepted definition. Even the terminology of OOP can vary greatly from one system or language to another. This paper introduces OOP to the newcomer in a language-independent manner. The underlying theory of OOP is presented to give the reader the basics necessary to understand the nuances of the various OOP languages that are available. Several OOP languages are briefly considered, as are object-oriented database management systems, object-based programming, and object-oriented design. Various problem areas are explore in detail. This paper should also be of considerable help in making the transition from one OOP language to another.

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r= 0.76 and r= 0.69, while that for repeatability was r= 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.

Concern for the growth and development of poor inner-city children prompted an investigation of the relationship of growth to diet, health and sociological background. Between 1973 and 1976, 1000 households in poor areas of London were screened for at-risk children between the ages of one and 12 years. Two hundred and thirty-one children from 112 families qualified for the survey. Of the white children, 21 per cent fell below the 10th percentile for height. The mean energy intake of the shortest children was 72 per cent of the RDI. Half the families spent 4.80 pounds or less per person per week on food, and 33 per cent of the children fell below the 10th percentile for height. A remedial feeding programme may be of benefit to these and similar children.

In prospective studies of diet it is often necessary to know for how many days subjects should record food consumption in order to be able to rank subjects correctly according to their nutrient intakes. Data from six studies--of toddlers, families, schoolchildren, dietitians, pregnant women, and elderly subjects--were analyzed to estimate the number of recording days necessary for energy, 28 nutrients, and the ratio of polyunsaturated to saturated fatty acids (P:S). The most striking finding is that 7 d of diet record do not rank subjects with the degree of accuracy commonly assumed. For some nutrients, such as iron, zinc, nicotinic acid, and pyridoxine, it may be desirable to record diet over a number of short, separate periods to achieve the number of days required. For others, such as copper, retinol, carotene, vitamin B-12, polyunsaturated fatty acids, P:S, and alcohol, alternative methods of assessment based on dietary histories or questionnaires may be more appropriate.

Missing web pages, URIs that return the 404 "Page Not Found" error or the HTTP response code 200 but dereference unexpected content, are ubiquitous in today's browsing experience. We use Internet search engines to relocate such missing pages and provide means that help automate the rediscovery process. We propose querying web pages' titles against search engines. We investigate the retrieval performance of titles and compare them to lexical signatures which are derived from the pages' content. Since titles naturally represent the content of a document they intuitively change over time. We measure the edit distance between current titles and titles of copies of the same pages obtained from the Internet Archive and display their evolution. We further investigate the correlation between title changes and content modifications of a web page over time. Lastly we provide a predictive model for the quality of any given web page title in terms of its discovery performance. Our results show that titles return more than 60% URIs top ranked and further relevant content returned in the top 10 results. We show that titles decay slowly but are far more stable than the pages' content. We further distill stop titles than can help identify insufficiently performing search engine queries., 10 pages, 8 figures, 4 tables, 37 references, accepted for publication at Hypertext 2010 in Toronto, Canada

Archiving the web is socially and culturally critical, but presents problems of scale. The Internet Archive's Wayback Machine can replay captured web pages as they existed at a certain point in time, but it has limited ability to provide extensive content and structural metadata about the web graph. While the live web has developed a rich ecosystem of APIs to facilitate web applications (e.g., APIs from Google and Twitter), the web archiving community has not yet broadly implemented this level of access. We present ArcLink, a proof-of-concept system that complements open source Wayback Machine installations by optimizing the construction, storage, and access to the temporal web graph. We divide the web graph construction into four stages (filtering, extraction, storage, and access) and explore optimization for each stage. ArcLink extends the current Web archive interfaces to return content and structural metadata for each URI. We show how this API can be applied to such applications as retrieving inlinks, outlinks, anchortext, and PageRank.

When a user views an archived page using the archive's user interface (UI), the user selects a datetime to view from a list. The archived web page, if available, is then displayed. From this display, the web archive UI attempts to simulate the web browsing experience by smoothly transitioning between archived pages. During this process, the target datetime changes with each link followed; drifting away from the datetime originally selected. When browsing sparsely-archived pages, this nearly-silent drift can be many years in just a few clicks. We conducted 200,000 acyclic walks of archived pages, following up to 50 links per walk, comparing the results of two target datetime policies. The Sliding Target policy allows the target datetime to change as it does in archive UIs such as the Internet Archive's Wayback Machine. The Sticky Target policy, represented by the Memento API, keeps the target datetime the same throughout the walk. We found that the Sliding Target policy drift increases with the number of walk steps, number of domains visited, and choice (number of links available). However, the Sticky Target policy controls temporal drift, holding it to less than 30 days on average regardless of walk length or number of domains visited. The Sticky Target policy shows some increase as choice increases, but this may be caused by other factors. We conclude that based on walk length, the Sticky Target policy generally produces at least 30 days less drift than the Sliding Target policy., 10 pages, JCDL 2013

The Memento aggregator currently polls every known public web archive when serving a request for an archived web page, even though some web archives focus on only specific domains and ignore the others. Similar to query routing in distributed search, we investigate the impact on aggregated Memento TimeMaps (lists of when and where a web page was archived) by only sending queries to archives likely to hold the archived page. We profile twelve public web archives using data from a variety of sources (the web, archives' access logs, and full-text queries to archives) and discover that only sending queries to the top three web archives (i.e., a 75% reduction in the number of queries) for any request produces the full TimeMaps on 84% of the cases., Comment: Appeared in TPDL 2013

When retrieving archived copies of web resources (mementos) from web archives, the original resource's URI-R is typically used as the lookup key in the web archive. This is straightforward until the resource on the live web issues a redirect: R ->R`. Then it is not clear if R or R` should be used as the lookup key to the web archive. In this paper, we report on a quantitative study to evaluate a set of policies to help the client discover the correct memento when faced with redirection. We studied the stability of 10,000 resources and found that 48% of the sample URIs tested were not stable, with respect to their status and redirection location. 27% of the resources were not perfectly reliable in terms of the number of mementos of successful responses over the total number of mementos, and 2% had a reliability score of less than 0.5. We tested two retrieval policies. The first policy covered the resources which currently issue redirects and successfully resolved 17 out of 77 URIs that did not have mementos of the original URI, but did of the resource that was being redirected to. The second policy covered archived copies with HTTP redirection and helped the client in 58% of the cases tested to discover the nearest memento to the requested datetime.

A number of methods have been developed to assist subjects in providing an estimate of portion size but their application in improving portion size estimation by children has not been investigated systematically. The aim was to develop portion size assessment tools for use with children and to assess the accuracy of children's estimates of portion size using the tools. The tools were food photographs, food models and an interactive portion size assessment system (IPSAS). Children (n201), aged 4–16 years, were supplied with known quantities of food to eat, in school. Food leftovers were weighed. Children estimated the amount of each food using each tool, 24 h after consuming the food. The age-specific portion sizes represented were based on portion sizes consumed by children in a national survey. Significant differences were found between the accuracy of estimates using the three tools. Children of all ages performed well using the IPSAS and food photographs. The accuracy and precision of estimates made using the food models were poor. For all tools, estimates of the amount of food served were more accurate than estimates of the amount consumed. Issues relating to reporting of foods left over which impact on estimates of the amounts of foods actually consumed require further study. The IPSAS has shown potential for assessment of dietary intake with children. Before practical application in assessment of dietary intake of children the tool would need to be expanded to cover a wider range of foods and to be validated in a ‘real-life’ situation.

We describe NCSTRL+, a unified, canonical digital library for scientific and technical information (STI). NCSTRL+ is based on the Networked Computer Science Technical Report Library (NCSTRL), a World Wide Web (WWW) accessible digital library (DL) that provides access to over 100 university departments and laboratories. NCSTRL+ implements two new technologies: cluster functionality and publishing "buckets". We have extended Dienst, the protocol underlying NCSTRL, to provide the ability to "cluster" independent collections into a logically centralized digital library based upon subject category classification, type of organization, and genres of material. The bucket construct provides a mechanism for publishing and managing logically linked entities with multiple data forms as a single object. The NCSTRL+ prototype DL contains the holdings of NCSTRL and the NASA Technical Report Server (NTRS). The prototype demonstrates the feasibility of publishing into a multi-cluster DL, searching across clusters, and storing and presenting buckets of information.

Although user access patterns on the live web are well-understood, there has been no corresponding study of how users, both humans and robots, access web archives. Based on samples from the Internet Archive's public Wayback Machine, we propose a set of basic usage patterns: Dip (a single access), Slide (the same page at different archive times), Dive (different pages at approximately the same archive time), and Skim (lists of what pages are archived, i.e., TimeMaps). Robots are limited almost exclusively to Dips and Skims, but human accesses are more varied between all four types. Robots outnumber humans 10:1 in terms of sessions, 5:4 in terms of raw HTTP accesses, and 4:1 in terms of megabytes transferred. Robots almost always access TimeMaps (95% of accesses), but humans predominately access the archived web pages themselves (82% of accesses). In terms of unique archived web pages, there is no overall preference for a particular time, but the recent past (within the last year) shows significant repeat accesses.

Visualization eases insight into complex systems such as co-authorship networks. We present an initial deployment of an author navigator application for convenient visual examination of JCDL and LANL co--authorship networks.

The Internet Archive's (IA) Wayback Machine is the largest and oldest public Web archive and has become a significant repository of our recent history and cultural heritage. Despite its importance, there has been little research about how it is discovered and used. Based on Web access logs, we analyze what users are looking for, why they come to IA, where they come from, and how pages link to IA. We find that users request English pages the most, followed by the European languages. Most human users come to Web archives because they do not find the requested pages on the live Web. About 65 % of the requested archived pages no longer exist on the live Web. We find that more than 82 % of human sessions connect to the Wayback Machine via referrals from other Web sites, while only 15 % of robots have referrers. Most of the links (86 %) from Websites are to individual archived pages at specific points in time, and of those 83 % no longer exist on the live Web. Finally, we find that users who come from search engines browse more pages than users who come from external Web sites.

The Potato in the Human Diet. By Jennifer A. Woolfe. Cambridge University Press: 1987. Pp. 231. £17.50, $32.50.

How to Live Longer and Feel Better. By Linus Pauling W.H. Freeman:1986. Pp.322. Hbk 15.95, 15.95; pbk 7.95, 5.95.