336 research outputs found
Workflow simulation for operational decision support using YAWL and ProM
Simulation is widely used as a tool for analyzing business processes but is mostly focused on examining rather abstract steady-state situations. Such analyses are helpful for the initial design of a business process but are less suitable for operational decision making and continuous improvement. Here we describe a simulation system for operational decision support in the context of work ow management. To do this we exploit not only the work ow's design, but also logged data describing the system's observed historic behavior, and information extracted about the current state of the work ow. Making use of actual data capturing the current state and historic information allows our simulations to accurately predict potential near-future behaviors for dierent scenarios. The approach is supported by a practical toolset which combines and extends the work ow management system YAWL and the process mining framework ProM. This technical report contains a detailed description of how a simulation model including operational decision support can be generated by our software based on the running example
From Understory to Canopy: In situ Behavior of Neotropical Forest Katydids in Response to Bat Echolocation Calls
Predator-prey interactions take place in complex environments, and research on the sensory ecology of predator-detection relies on understanding when, where, and how prey experience and respond to predator cues. Bats are significant nocturnal predators, and insects have evolved diverse strategies for avoiding predation by bats. While it is well-known that insects exhibit anti-bat strategies, from avoidance flight to reduced acoustic signaling, the specific conditions that elicit some of these behaviors are less well-known. To illuminate how insects respond to bats in nature, we studied how calling behavior changed when katydids experienced echolocation calls in a Neotropical forest. The diverse Neotropical bat community includes species that eavesdrop on prey sounds, such as the songs produced by male katydids. Previous research has shown that some katydid species respond to echolocation calls by reducing acoustic signaling. To capture the interactions of bats and katydids, we placed acoustic monitors at heights of 8, 16, and 24 meters above ground in 10 locations in the forest on Barro Colorado Island, Panama and recorded continuously for 24 h at each location. We randomly selected 250 recordings with echolocation calls and compared the acoustic spectrum of the forest before a bat arrived, when a bat was present, and after the bat was no longer detectable. We tested whether the response to bat calls changes with height, the family of bat producing the calls, the duration of the echolocation sequence, call amplitude, and call peak frequency. Bats appeared on ~50% of nighttime recordings, but echolocation calls that could have been produced by eavesdropping bats were rare (<4% of calls). Insect response to bats was nuanced and context-dependent. Despite the rarity of truly dangerous predator cues, echolocation decreased insect sound at several frequencies and heights. Insect response was not uniform, and in many cases echolocation calls had little effect on insect activity, perhaps reflecting the fact that echolocation calls were an inconsistent cue for the presence of eavesdropping bats. These nuanced responses raise interesting questions about predator detection in noise and provide valuable context for laboratory investigations on the sensory ecology of how individual prey species respond to predator cues
Recommended from our members
Continuous Monitoring in Evolving Business Networks
The literature on continuous monitoring of cross-organizational processes, executed within virtual enterprises or business networks, considers monitoring as an issue regarding the network formation, since what can be monitored during process execution is fixed when the network is established. In particular, the impact of evolving agreements in such networks on continuous monitoring is not considered. Also, monitoring is limited to process execution progress and simple process data. In this paper, we extend the possible monitoring options by linking monitoring requirements to generic clauses in agreements established across a network and focus on the problem of preserving the continuous monitorability of these clauses when the agreements evolve, i.e. they are introduced, dropped, or updated. We discuss mechanisms to preserve continuous monitorability in a business network for different types of agreement evolution and we design a conceptual and technical architecture for a continuous monitoring IT infrastructure that implements the requirements derived from such mechanisms
Sensory-based niche partitioning in a multiple predator-multiple prey community
Many predators and parasites eavesdrop on the communication signals of their prey. Eavesdropping is typically studied as dyadic predator-prey species interactions; yet in nature, most predators target multiple prey species and most prey must evade multiple predator species. The impact of predator communities on prey signal evolution is not well understood. Predators could converge in their preferences for conspicuous signal properties, generating competition among predators and natural selection on particular prey signal features. Alternatively, predator species could vary in their preferences for prey signal properties, resulting in sensory-based niche partitioning of prey resources. In the Neotropics, many substrate-gleaning bats use the mate-attraction songs of male katydids to locate them as prey. We studied mechanisms of niche partitioning in four substrate- gleaning bat species and found they are similar in morphology, echolocation signal design and prey-handling ability, but each species preferred different acoustic features of male song in 12 sympatric katydid species. This divergence in predator preference probably contributes to the coexistence of many substrate-gleaning bat species in the Neotropics, and the substantial diversity in the mate-attraction signals of katydids. Our results provide insight into how multiple eavesdropping predator species might influence prey signal evolution through sensory-based niche partitioning
Indexing and efficient instance-based retrieval of process models using untanglings
Process-Aware Information Systems (PAISs) support executions of operational processes that involve people, resources, and software applications on the basis of process models. Process models describe vast, often infinite, amounts of process instances, i.e., workflows supported by the systems. With the increasing adoption of PAISs, large process model repositories emerged in companies and public organizations. These repositories constitute significant information resources. Accurate and efficient retrieval of process models and/or process instances from such repositories is interesting for multiple reasons, e.g., searching for similar models/instances, filtering, reuse, standardization, process compliance checking, verification of formal properties, etc. This paper proposes a technique for indexing process models that relies on their alternative representations, called untanglings. We show the use of untanglings for retrieval of process models based on process instances that they specify via a solution to the total executability problem. Experiments with industrial process models testify that the proposed retrieval approach is up to three orders of magnitude faster than the state of the art
PELAJAR ANTARABANGASA TERUJA SAMBUNG PENGAJIAN DI USM
NIBONG TEBAL, 30 Ogos 2016 – Tiga daripada lima pelajar antarabangsa yang mendaftar diri sebagai
pelajar kejuruteraan teruja untuk menyambung pengajian di Kampus Kejuruteraan, Universiti Sains
Malaysia (USM) di sini semalam
TLR1/TLR2 Heterodimers Play an Important Role in the Recognition of Borrelia Spirochetes
After infection with Borrelia species, the risk for developing Lyme disease varies significantly between individuals. Recognition of Borrelia by the immune system is mediated by pattern recognition receptors (PRRs), such as TLRs. While TLR2 is the main recognition receptor for Borrelia spp., little is known about the role of TLR1 and TLR6, which both can form functionally active heterodimers with TLR2. Here we investigated the recognition of Borrelia by both murine and human TLR1 and TLR6. Peritoneal macrophages from TLR1- and TLR6- gene deficient mice were isolated and exposed to Borrelia. Human PBMCs were stimulated with Borrelia with or without specific TLR1 and TLR6 blocking using specific antibodies. Finally, the functional consequences of TLR polymorphisms on Borrelia-induced cytokine production were assessed. Splenocytes isolated from both TLR1−/− and TLR6−/− mice displayed a distorted Th1/Th2 cytokine balance after stimulation with B.burgdorferi, while no differences in pro-inflammatory cytokine production were observed. In contrast, blockade of TLR1 with specific neutralizing antibodies led to decreased cytokine production by human PBMCs after exposure to B.burgdorferi. Blockade of human TLR6 did not lead to suppression of cytokine production. When PBMCs from healthy individuals bearing polymorphisms in TLR1 were exposed to B.burgdorferi, a remarkably decreased in vitro cytokine production was observed in comparison to wild-type controls. TLR6 polymorphisms lead to a minor modified cytokine production. This study indicates a dominant role for TLR1/TLR2 heterodimers in the induction of the early inflammatory response by Borrelia spirochetes in humans
Relationships between population spatial occupation and population dynamics
Population dynamics is commonly described non-spatially using parameters of population demography and vital traits. Population spatial organisation is therefore considered implicit and its importance in the population dynamics ignored. The present study evidences on a variety of stocks correlation between population spatial distribution indices, population abundance, recruitment and mortality. Series of research fisheries monitoring surveys were considered for a range of different stocks (cod, herring, anchovy, hake, mullet) in different regions of the North East Atlantic and Mediterranean (North Sea, Barents Sea, Baltic Sea, Bay of Biscay, Tyrrhenian Sea, Ionian Sea and Aegean Sea). For each population, each age and each year, 9 spatial indices were computed that characterised the spatial distribution in their centre of gravity, inertia, anisotropy, extension areas, number of patches and microscale structure. For each population and age, spatial indices were linearly regressed on the abundance, on the following recruitment, and on the mortality residuals (as a constant mortality has been fitted on cohort curves). A metaanalysis table was constructed that showed the number of times that correlations were significant. The result is that spatial indices provide additional indicators for assessing population status and could be helpful in the context of stock decline and habitat loss
- …