Prospects of caching in a distributed digital library

Many independent publishers are today offering digital libraries with fulltext archives. In an attempt to provide a single user-interface to a large set of archives, DTVs Article Database Service, offers a consolidatedinterface to a geographically distributed set of archives. While this approach offers a tremendous functional advantage to a user, the delays caused by the network and queuing delays in servers make the user-perceived interactive performance poor. In this paper, we study the prospects of caching articles at the client level as wel as intermediate points as manifested by gateways that implement the interfaces to the many fulltext archives. A central research question is what the nature of the locality is in the user accesses to such a digital library. Based on access logs to drive simulations, we find that client side caching can result in a 20% hitrate. However, at the gateway level, where multiple users may access the same article, the temporal locality is poor and caching is not so relevant. We have also studied whether spatial locality can be exploited by considering to load into cache all articles in an issue, volume, or journal, if a single article is accessed, but found that spatial locality is quite poor

Recovering from a Decade: A Systematic Mapping of Information Retrieval Approaches to Software Traceability

Engineers in large-scale software development have to manage large amounts of information, spread across many artifacts. Several researchers have proposed expressing retrieval of trace links among artifacts, i.e. trace recovery, as an Information Retrieval (IR) problem. The objective of this study is to produce a map of work on IR-based trace recovery, with a particular focus on previous evaluations and strength of evidence. We conducted a systematic mapping of IR-based trace recovery. Of the 79 publications classified, a majority applied algebraic IR models. While a set of studies on students indicate that IR-based trace recovery tools support certain work tasks, most previous studies do not go beyond reporting precision and recall of candidate trace links from evaluations using datasets containing less than 500 artifacts. Our review identified a need of industrial case studies. Furthermore, we conclude that the overall quality of reporting should be improved regarding both context and tool details, measures reported, and use of IR terminology. Finally, based on our empirical findings, we present suggestions on how to advance research on IR-based trace recovery

Cow claws on concrete slats in the waiting area in a dairy barn estimated by use of Image analysis

Slatted concrete floors are commonly used in dairy barns for aisles, feeding and waiting areas. Maximum slot opening in Sweden is 35 mm with a maximum of 28% opening area for adult cattle in order to provide the adequate claw support. The construction of the slats has to consider this together with the length of the slats and the load from the weight of the animals on the slats. Presently, the dimension of the load strength of slats is based on assumptions and experience. An alternative approach is to estimate the true load of the animals on the slats by observation of animal distribution on slatted floors. The purpose of this study was to investigate possibilities of using machine learning algorithms and image analysis for assessing actual distribution of animals in the areas of interest and maximal weight load per slat element per unit of time. Images for the study were acquired from three surveillance cameras placed in the ceiling above the common waiting area (size 6x18 m) with entrances to four automatic milking systems (AMS). Then images were used to train a convolutional neural net classifier to detect and locate the cows in the images. Then, a probability distribution of where the claws might be located was constructed. By using this distribution in a Monte Carlo simulation, a probability distribution of the number of claws on each slat could be estimated, and from that, a worst-case estimate of the actual weight load was constructed. Results indicate that the 95% percentile number of claws on 160 mm wide slat area (slat width including the opening) was estimated to 3.03 and on a 560 mm slat area width was 5.63. Cows mounting was found in 7 of 9215 (0.2 %) examined pictures. The method proposed in this report was promising and for this purpose and could be used for practical assessment of animal distribution and loading and thus be a part of the dimensioning of construction

Focused crawling in the ALVIS semantic search engine

The EU project ALVIS - Superpeer Semantic Search Engine, aiming at developing an Open Source prototype of a peer-to-peer, semantic based search engine, is brie°y presented. A focused (or topic speci¯c) crawler, responsible for creating topic-speci¯c databases within ALVIS, is presented in more detail. It is based on a combination of a standard Web crawler and an automated subject classi¯er. The topic focus is provided by an ontology that is used as topic de¯nition. When a document have been deemed relevant further processing (like character set normalization, language identi ¯cation and simple text segmentation), is done in preparation for the ALVIS processing pipeline