Time and information retrieval: Introduction to the special issue

The Special Issue of Information Processing and Management includes research papers on the intersection between time and information retrieval. In 'Evaluating Document Filtering Systems over Time', Tom Kenter and Krisztian Balog propose a time-aware way of measuring a system's performance at filtering documents. Manika Kar, SeAa7acute;rgio Nunes and Cristina Ribeiro present interesting methods for summarizing changes in dynamic text collections over time in their paper 'Summarization of Changes in Dynamic Text Collection using Latent Dirichlet Allocation Model.' Hideo Joho, Adam Jatowt and Roi Blanco report on the temporal information searching behaviour of users and their strategies for dealing with searches that have a temporal nature in 'Temporal Information Searching Behaviour and Strategies', a user study. In controlled settings, thirty participants are asked to perform searches on an array of topics on the web to find information related to particular time scopes. Adam Jatowt, Ching-man Au Yeung and Katsumi Tanaka present a 'Generic Method for Detecting Content Time of Documents'. The authors propose several methods for estimating the focus time of documents, i.e. the time a document's content refers to. Xujian Zhao, Peiquan Jin and Lihua Yue present an approach to determining the time of the underlying topic or event in their article entitled 'Discovering Topic Time from Web News'

Towards memory supporting personal information management tools

In this article we discuss re-retrieving personal information objects and relate the task to recovering from lapse(s) in memory. We propose that fundamentally it is lapses in memory that impede users from successfully re-finding the information they need. Our hypothesis is that by learning more about memory lapses in non-computing contexts and how people cope and recover from these lapses, we can better inform the design of PIM tools and improve the user's ability to re-access and re-use objects. We describe a diary study that investigates the everyday memory problems of 25 people from a wide range of backgrounds. Based on the findings, we present a series of principles that we hypothesize will improve the design of personal information management tools. This hypothesis is validated by an evaluation of a tool for managing personal photographs, which was designed with respect to our findings. The evaluation suggests that users' performance when re-finding objects can be improved by building personal information management tools to support characteristics of human memory

Linear tracks and restricted temperature ranges characterise penguin foraging pathways

Marine predators are thought to follow sophisticated scale-dependent search strategies when seeking patchy and unpredictable prey. However, fine-scale information about these strategies has hitherto been difficult to obtain for diving predators that often remain at the sea surface for only limited periods of time. Using ARGOS telemetry and novel, low-powered, archival GPS, we followed the fine-scale at-sea behaviour of king penguins breeding on South Georgia. Results revealed that foraging pathways were generally linear, except at the finest scale, where movements probably reflected either fine-scale searching behaviour, or fine-scale random movements associated with having found prey. King penguins focused 45% of their foraging effort in waters with a specific surface temperature (5.0 to 5.5 degrees C) - an environmental cue potentially important in helping them locate prey, thereby reducing their need to expend energy in area-restricted search patterns. Within these waters, penguins slowed down and increased their dive effort and degree of meandering. First Passage Time analysis revealed that penguins focused much of their effort at local scales, generally in areas with a radius of 2 km. In these areas, penguins dived marginally deeper and targeted waters that, were significantly warmer at the bottom of their dives. Such information about fine-scale foraging behaviour will help increase our understanding of the environmental correlates that characterise areas where marine predators exploit their prey. The scale of these behavioural processes is better resolved using the fine-scale temporal and spatial resolution of GPS tracking data

Visual search and decision making in bees: time, speed and accuracy

An insect searching a meadow for flowers may detect several flowers from different species per second, so the task of choosing the right flowers rapidly is not trivial. Here we apply concepts from the field of visual search in human experimental psychology to the task a bee faces in searching a meadow for familiar flowers, and avoiding ‘‘distraction’’ by unknown or unrewarding flowers. Our approach highlights the importance of visual information processing for understanding the behavioral ecology of foraging. Intensity of illuminating light, target contrast with background (both chromatic and achromatic), and number of distractors are all shown to have a direct influence on decision times in behavioral choice experiments. To a considerable extent, the observed search behavior can be explained by the temporal and spatial properties of neuronal circuits underlying visual object detection. Our results also emphasize the importance of the time dimension in decision making. During visual search in humans, improved accuracy in solving discrimination tasks comes at a cost in response time, but the vast majority of studies on decision making in animals have focused on choice accuracy, not speed. We show that in behavioral choice experiments in bees, there is a tight link between the two. We demonstrate both between-individual and within- individual speed-accuracy tradeoffs, whereby bees exhibit considerable behavioral flexibility in solving visual search tasks. Motivation is an important factor in selection of behavioral strategies for a search task, and sensory discrimination capabilities may be underestimated by studies that quantify accuracy of behavioral choice but neglect the temporal dimension

Strategy Synthesis for Autonomous Agents Using PRISM

We present probabilistic models for autonomous agent search and retrieve missions derived from Simulink models for an Unmanned Aerial Vehicle (UAV) and show how probabilistic model checking and the probabilistic model checker PRISM can be used for optimal controller generation. We introduce a sequence of scenarios relevant to UAVs and other autonomous agents such as underwater and ground vehicles. For each scenario we demonstrate how it can be modelled using the PRISM language, give model checking statistics and present the synthesised optimal controllers. We conclude with a discussion of the limitations when using probabilistic model checking and PRISM in this context and what steps can be taken to overcome them. In addition, we consider how the controllers can be returned to the UAV and adapted for use on larger search areas

Utilisation of intensive foraging zones by female Australian fur seals.

Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search). For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour) determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity 'hot spots' were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a foraging patch

Modelling foraging movements of diving predators : A theoretical study exploring the effect of heterogeneous landscapes on foraging efficiency

Peer reviewedPublisher PD

Searching the intranet: Corporate users and their queries

By examining the log files from a corporate intranet search engine, we have analysed the actual web searching behaviour of real users in a real business environment. While building on previous research on public search engines, we apply an alternative session definition that we argue is more appropriate. Our results regarding session length, query construction and result page viewing confirm some of the findings from similar studies carried out on public search engines but further our understanding of web searching by presenting details on corporate users’ activities. In particular, we suggest that search sessions are shorter than previously suggested, search queries have fewer terms than observed for public search engines, and number of examined result pages is smaller than reported in other research. More research on how corporate intranet users search for information is needed

Influence of temperature on host location and multisensory orientation in the parasitoid Pimpla turionellae (L.) (Hymenoptera)

The ichneumonid wasp Pimpla turionellae (L.) (Hymenoptera) is a specialist parasitoid of lepidopteran pupae, and has to overcome the challenge of reduced chemical and visual cues as pupae are immobile, do not feed and do not emit excrements. Certain hymenopteran species have developed a particular mechanosensory mechanism in order to locate hosts hidden in hollow spaces inside of plant material (Broad & Quicke 2000). Similar to echolocation they use self-produced vibrations, instead of sounds, that are transmitted by the antennae onto the substrate. In analogous way to acoustics, this mechanosensory mechanism is referred to as vibrational sounding (Wäckers & al. 1998). Thermal dependence is well known in acoustical and vibrational communication of arthropods (e.g. Pires & Hoy 1992, Shimizu & Barth 1996) and is likewise presumed to affect mechanosensory host location by vibrational sounding. The species P. turionellae has recently been found to use vibrational sounding successfully in a temperature range from 8 to 28°C, but with less performance of searching behaviour and an adjusted signal production at extreme temperatures (Kroder & al. 2006, & al. 2007b, Samietz & al. 2006). Many insects have evolved strategies to maintain a balance of body temperature by ecto- and endothermic means. Raising and maintaining body temperatures above the ambient environment by endothermic means is particularly known in several hymenopteran species (Heinrich 1993). In the case of a thermally influenced host location mechanism, such means of thermoregulation could be supposed as well in order to maintain performance with changing temperatures. The study elucidates if the wasps are able to regulate their body temperature at suboptimal conditions during vibrational sounding and furthermore examines the role of vibrational sounding in multisensory orientation at different ambient temperatures.Die Schlupfwespe Pimpla turionellae parasitiert versteckte Lepidopterenpuppen und orientiert sie sich bei der Wirtssuche multisensorisch mittels visueller Reize und aktiver Vibrationsortung mit selbst produzierten Schwingungen (Vibrational-Sounding). Die Studie untersucht, inwieweit die Wespen bei Änderung der Umgebungstemperaturen von 8-26°C (1) zwischen der temperatur-sensitiven vibratorischen und der -insensitiven visuellen Orientierung wechseln und (2) gegebenenfalls selbst die Körpertemperatur regulieren können, um die sehr präzise Vibrationsortung bei niedrigen Temperaturen aufrechtzuerhalten. Messungen mit Infrarot-Thermographie zeigen, dass suchende Wespen leicht erhöhte Körpertemperaturen während der vibratorischen Wirtssuche aufweisen, welche auf metabolische Wärmeproduktion zurückzuführen sind. Wahlexperimente unter kontrollierten Temperaturen zeigen zudem, dass die Nutzung der temperatur-sensitiven vibratorischen Reize bei pessimalen Temperaturen abnimmt und die Wespen auf fast ausschließliche visuelle Orientierung wechseln. Folglich wird die Relevanz einzelner Reize bei der multisensorischen Orientierung direkt vom Faktor Temperatur beeinflusst. Solange ein zuverlässiger Reiz vorhanden ist, nimmt dabei auch die Präzision der Lokalisation insgesamt nicht ab