Compact Markov-modulated models for multiclass trace fitting

Markov-modulated Poisson processes (MMPPs) are stochastic models for fitting empirical traces for simulation, workload characterization and queueing analysis purposes. In this paper, we develop the first counting process fitting algorithm for the marked MMPP (M3PP), a generalization of the MMPP for modeling traces with events of multiple types. We initially explain how to fit two-state M3PPs to empirical traces of counts. We then propose a novel form of composition, called interposition, which enables the approximate superposition of several two-state M3PPs without incurring into state space explosion. Compared to exact superposition, where the state space grows exponentially in the number of composed processes, in interposition the state space grows linearly in the number of composed M3PPs. Experimental results indicate that the proposed interposition methodology provides accurate results against artificial and real-world traces, with a significantly smaller state space than superposed processes

Seasonal residency of loggerhead turtles Caretta caretta tracked from the Gulf of Manfredonia, south Adriatic

A detailed knowledge of sea turtle distribution in relation to anthropogenic threats is key to inform conservation measures. We satellite tracked five loggerhead turtles incidentally caught in the Gulf of Manfredonia, where a high turtle occurrence and high bycatch levels have been recently reported. Turtles were tracked for a period ranging from 27 to 367 days, with a minimum travel distance ranging from 151 to 4,300 km. With the caution due to the small sample size, results suggest that: (i) the area may host residential loggerhead turtles at least in summer, while they probably move elsewhere in winter due to the low temperatures occurring in shallow waters, (ii) turtles may have very small home ranges in the area, (iii) turtle occurrence may be higher in shallow waters along the coast. Moreover (iv) one turtle showed remarkable fidelity to the same spot after seasonal migration and constant migration paths. If confirmed and further detailed, such movement patterns may guide effective conservation strategies to reduce the impact of bycatch in the area

An Uncertainty-Aware Approach to Optimal Configuration of Stream Processing Systems

Finding optimal configurations for Stream Processing Systems (SPS) is a challenging problem due to the large number of parameters that can influence their performance and the lack of analytical models to anticipate the effect of a change. To tackle this issue, we consider tuning methods where an experimenter is given a limited budget of experiments and needs to carefully allocate this budget to find optimal configurations. We propose in this setting Bayesian Optimization for Configuration Optimization (BO4CO), an auto-tuning algorithm that leverages Gaussian Processes (GPs) to iteratively capture posterior distributions of the configuration spaces and sequentially drive the experimentation. Validation based on Apache Storm demonstrates that our approach locates optimal configurations within a limited experimental budget, with an improvement of SPS performance typically of at least an order of magnitude compared to existing configuration algorithms

Is depression a real risk factor for acute myocardial infarction mortality? A retrospective cohort study

Background: Depression has been associated with a higher risk of cardiovascular events and a higher mortality in patients with one or more comorbidities. This study investigated whether continuative use of antidepressants (ADs), considered as a proxy of a state of depression, prior to acute myocardial infarction (AMI) is associated with a higher mortality afterwards. The outcome to assess was mortality by AD use. Methods: A retrospective cohort study was conducted in the Veneto Region on hospital discharge records with a primary diagnosis of AMI in 2002-2015. Subsequent deaths were ascertained from mortality records. Drug purchases were used to identify AD users. A descriptive analysis was conducted on patients' demographics and clinical data. Survival after discharge was assessed with a Kaplan-Meier survival analysis and Cox's multiple regression model. Results: Among 3985 hospital discharge records considered, 349 (8.8%) patients were classified as AD users'. The mean AMI-related hospitalization rate was 164.8/100,000 population/year, and declined significantly from 204.9 in 2002 to 130.0 in 2015, but only for AD users (-40.4%). The mean overall follow-up was 4.64.1years. Overall, 523 patients (13.1%) died within 30days of their AMI. The remainder survived a mean 5.3 +/- 4.0years. After adjusting for potential confounders, use of antidepressants was independently associated with mortality (adj OR=1.75, 95% CI: 1.40-2.19). Conclusions: Our findings show that AD users hospitalized for AMI have a worse prognosis in terms of mortality. The use of routinely-available records can prove an efficient way to monitor trends in the state of health of specific subpopulations, enabling the early identification of AMI survivors with a history of antidepressant use

Geocoding health data with Geographic Information Systems: a pilot study in northeast Italy for developing a standardized data-acquiring format

Introduction. Geographic Information Systems (GIS) have become an innovative and somewhat crucial tool for analyzing relationships between public health data and environment. This study, though focusing on a Local Health Unit of northeastern Italy, could be taken as a benchmark for developing a standardized national data-acquiring format, providing a step-by-step instructions on the manipulation of address elements specific for Italian language and traditions. Methods. Geocoding analysis was carried out on a health database comprising 268,517 records of the Local Health Unit of Rovigo in the Veneto region, covering a period of 10 years, starting from 2001 up to 2010. The Map Service provided by the Environmental Research System Institute (ESRI, Redlands, CA), and ArcMap 10.0 by ESRI\uae were, respectively, the reference data and the GIS software, employed in the geocoding process. Results. The first attempt of geocoding produced a poor quality result, having about 40% of the addresses matched. A procedure of manual standardization was performed in order to enhance the quality of the results, consequently a set of guiding principle were expounded which should be pursued for geocoding health data. High-level geocoding detail will provide a more precise geographic representation of health related events. Conclusions. The main achievement of this study was to outline some of the difficulties encountered during the geocoding of health data and to put forward a set of guidelines, which could be useful to facilitate the process and enhance the quality of the results. Public health informatics represents an emerging specialty that highlights on the application of information science and technology to public health practice and research. Therefore, this study could draw the attention of the National Health Service to the underestimated problem of geocoding accuracy in health related data for environmental risk assessment

Tri nove vrste i jedan novi rod ultraspecijaliziranih špiljskih leptodirina iz Hrvatske (Coleoptera, Cholevidae)

Croatodirus casalei Giachino & Jalžić, new species from N Velebit, Lubenovac, Slovačka jama pothole, and C. ozimeci Casale, Giachino & Jalžić new species, from Lokve, Lokvarka špilja cave, are described. The morphological features of the new taxa are compared with those of the type species of the genus (C. bozicevici Casale, Giachino & Jalžić, 2000). The genus is confirmed as a homogeneous, well characterized and monophyletic unit, and is attributed to the phyletic lineage of Anthroherpon. Velebitodromus, new genus, smidai new species, is described from N Velebit, Lubenovac, Mali kuk, Slovačka jama pothole. Owing to both external features and structures of male and female genitalia, the genus is attributed to the phyletic lineage of Anthroherpon, and is recognized as related to the genera Anthroherpon Reitter, 1889, and Paranthrophilon Reitter, 1889.U radu su opisane Croatodirus casalei Giachino & Jalžić, nova vrsta sa Sjevernog Velebita (Lubenovac, Mali kuk, Slovačka jama) i C. ozimeci Casale, Giachino & Jalžić, nova vrsta iz Lokava (špilja Lokvarka). Njihova morfološka svojstva uspoređuju se s onima tipske vrste ovog roda (C. bozicevici Casale, Giachino & Jalžić, 2000). Rod se potvrđuje kao homogen, jasno raspoznatljiv i monofiletički, te je pridodan filetičkoj liniji Anthroherpon. Novi rod Velebitodromus s novom vrstom smidai opisan je također sa Sjevernog Velebita (Lubenovac, Slovačka jama). Zbog vanjskih osobina i zbog građe muških i ženskih genitalija, rod je pridodan filetičkoj liniji Anthroherpon, i prepoznaje se kao srodan rodovima Anthroherpon Reitter, 1889 i Paranthrophilon Reitter, 1889

Mitochondrial DNA reveals regional and interregional importance of the central Mediterranean African shelf for loggerhead sea turtles (<em>Caretta caretta</em>)

The wide north African continental shelf in the central Mediterranean is known to be one of the few important areas in the basin for loggerhead turtles in the neritic stage. In order to assess the origin of these turtles, sequences of the mtDNA control region were obtained from 70 turtles caught by bottom trawlers in the area, and compared with known sequences from turtles from Mediterranean and Atlantic nesting sites. Five haplotypes were identified (Haplotype diversity = 0.262; nucleotide diversity = 5.4×10-3). Specific haplotypes indicate contributions from distant rookeries such as Turkey and the Atlantic, which shows that Atlantic turtles entering the Mediterranean while in the oceanic phase use at least one Mediterranean continental shelf as a neritic foraging ground. A new haplotype and another one previously found only in foraging areas, highlight the genetic information gaps for nesting sites, which undermine powerful mixed stock analyses. Despite these limitations, the results reveal the regional importance of the study area as a neritic foraging ground for turtles that are probably from most of the Mediterranean nesting aggregates. Therefore, reducing turtle mortality resulting from the high fishing effort in the area should be regarded as key for Mediterranean turtle conservation and is also possibly important for Atlantic populations

START: Straggler Prediction and Mitigation for Cloud Computing Environments using Encoder LSTM Networks

A common performance problem in large-scale cloud systems is dealing with straggler tasks that are slow running instances which increase the overall response time. Such tasks impact the system's QoS and the SLA. There is a need for automatic straggler detection and mitigation mechanisms that execute jobs without violating the SLA. Prior work typically builds reactive models that focus first on detection and then mitigation of straggler tasks, which leads to delays. Other works use prediction based proactive mechanisms, but ignore volatile task characteristics. We propose a Straggler Prediction and Mitigation Technique (START) that is able to predict which tasks might be stragglers and dynamically adapt scheduling to achieve lower response times. START analyzes all tasks and hosts based on compute and network resource consumption using an Encoder LSTM network to predict and mitigate expected straggler tasks. This reduces the SLA violation rate and execution time without compromising QoS. Specifically, we use the CloudSim toolkit to simulate START and compare it with IGRU-SD, SGC, Dolly, GRASS, NearestFit and Wrangler in terms of QoS parameters. Experiments show that START reduces execution time, resource contention, energy and SLA violations by 13%, 11%, 16%, 19%, compared to the state-of-the-art