Process mining using BPMN: relating event logs and process models

Process-aware information systems (PAIS) are systems relying on processes, which involve human and software resources to achieve concrete goals. There is a need to develop approaches for modeling, analysis, improvement and monitoring processes within PAIS. These approaches include process mining techniques used to discover process models from event logs, find log and model deviations, and analyze performance characteristics of processes. The representational bias (a way to model processes) plays an important role in process mining. The BPMN 2.0 (Business Process Model and Notation) standard is widely used and allows to build conventional and understandable process models. In addition to the flat control flow perspective, subprocesses, data flows, resources can be integrated within one BPMN diagram. This makes BPMN very attractive for both process miners and business users, since the control flow perspective can be integrated with data and resource perspectives discovered from event logs. In this paper, we describe and justify robust control flow conversion algorithms, which provide the basis for more advanced BPMN-based discovery and conformance checking algorithms. Thus, on the basis of these conversion algorithms low-level models (such as Petri nets, causal nets and process trees) discovered from event logs using existing approaches can be represented in terms of BPMN. Moreover, we establish behavioral relations between Petri nets and BPMN models and use them to adopt existing conformance checking and performance analysis techniques in order to visualize conformance and performance information within a BPMN diagram. We believe that the results presented in this paper can be used for a wide variety of BPMN mining and conformance checking algorithms. We also provide metrics for the processes discovered before and after the conversion to BPMN structures. Cases for which conversion algorithms produce more compact or more complicated BPMN models in comparison with the initial models are identified.     

Dynamic Virtual Resource Allocation in Virtualized multi-RAT Cellular Networks

The legacy wireless systems are designed to exploit static configuration and deployment, and cannot handle the discrepancies of the spatio-temporal traffic demand. Cloud RAN (C-RAN) is a novel flexible radio technology that utilizes the virtualization concepts and can efficiently address the static deployment of conventional wireless systems. The C-RAN also leverages high radio network flexibility by introducing the network function virtualization approach to wireless networks. This paper presents a novel C-RAN platform that virtualizes and operates with full GSM and LTE systems. The presented platform is solely based on open-source and off the shelf solutions, providing easy implementation, low cost and high scalability. The paper also introduces a novel dynamic resource allocation algorithm that facilitates the C-RAN’s optimal performance in dynamic scenarios. The proposed algorithm is analyzed and validated on the presented C-RAN platform. The results of the performance analysis clearly show the advantages of the proposed dynamic resource allocation algorithm. Moreover, they prove the applicability of the C-RAN platform for variety of different scenarios.     

Convenient approach to making nanocomposites based on a chitosan–poly(vinyl pyrrolidone) polymer matrix and a graphene nanofiller

Conducting, mechanically durable, elastic nanocomposite films were prepared with chitosan (CS) as the polymer matrix, graphene obtained from highly exfoliated graphite as the nanofiller, and poly(vinyl pyrrolidone) (PVP) as the stabilizer of the graphene sheets. The maximum graphene content in the composites without a loss of uniformity and other useful properties increased up to 4.0 wt %. The resulting composites were characterized by scanning electron microscopy, Raman spectroscopy, X‐ray diffraction analysis, mechanical testing, and electrical conductivity testing to determine the effects of the addition of graphene on the morphology and mechanical and electrical properties of the CS–PVP–graphene nanocomposite films. In this study, we took an approach to making nanocomposites from the perspectives of green chemistry, environmental protection, regenerative medicine, and low cost. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45038.     

High-Tc superconductor in an a.c. field

The behavior of high-T _c oxides in an alternating field is studied. The short coherence length and the layered structure require an unconventional microscopic analysis. The complex conductivity(, k) is evaluated. The frequency and temperature dependences of the impedance are obtained (in the region of small frequencies). The effect of impurities is discussed. The microwave properties of the proximity system S_h-N (S_h and N are high-T _c and normal films, respectively) are discussed.     

Hybrid incoherent optical pattern recognition system

A pattern recognition system that uses incoherent spatial filtering to recognize images directly from a narrowband phosphor television monitor is described. Images of real objects are captured with a television camera. These images are then edge-enhanced electronically and displayed on the TV monitor. The monitor output is used directly as the input to a holographic correlator. An optical multichannel analyzer at the correlation plane is used to analyze the shape of the correlation function and to determine the position of its peak. Experimental results agree well with theory. Concepts for handling rotation, aspect angle, and scale variations of the input are discussed.     

Transformation Toughening in Sol–Gel-Derived Alumina-Zirconia Composites

The microstructures of α-Al₂O₃ seeded sol–gel-derived alumina-zirconia composites containing 20 wt% unstabilized zirconia (processed from zirconium n-propoxide) were very fine, with submicrometer alumina grains and small, mainly intergranular zirconia particles, the latter having a critical size for the tetragonal-to-monoclinic phase transformation of 0.45 μm. The corresponding ratios of the toughening contribution to the matrix toughness are relatively low (δK_c/K₀<1). This finding is confirmed by an analysis of the tetragonal zirconia particle size dependence of the stress-induced transformation toughening.     

Automation of cell-based drug absorption assays in 96-well format using permeable support systems

Cell-based drug absorption assays, such as Caco-2 and MDCK-MDR1, are an essential component of lead compound ADME/Tox testing. The permeability and transport data they provide can determine whether a compound continues in the drug discovery process. Current methods typically incorporate 24-well microplates and are performed manually. Yet the need to generate absorption data earlier in the drug discovery process, on an increasing number of compounds, is driving the use of higher density plates. A simple, more efficient process that incorporates 96-well permeable supports and proper instrumentation in an automated process provides more reproducible data compared to manual methods. Here we demonstrate the ability to perform drug permeability and transport assays using Caco-2 or MDCKII-MDR1 cells. The assay procedure was automated in a 96-well format, including cell seeding, media and buffer exchanges, compound dispense, and sample removal using simple robotic instrumentation. Cell monolayer integrity was confirmed via transepithelial electrical resistance and Lucifer yellow measurements. Proper cell function was validated by analyzing apical-to-basolateral and basolateral-to-apical movement of rhodamine 123, a known P-glycoprotein substrate. Apparent permeability and efflux data demonstrate how the automated procedure provides a less variable method than manual processing, and delivers a more accurate assessment of a compound's absorption characteristics.     

Comparison of methods for calculating stress intensity factors with quarter-point elements

The quarter-point quadrilateral element is employed with various methods for calculating the stress intensity factor in order to provide guidelines for a best method. These methods include displacement extrapolation, J-integral and Griffith's energy calculations, and the stiffness derivative technique. Three geometries are considered: a central crack, a single edge crack and double edge cracks in a rectangular sheet. For these cases, it is observed that the stiffness derivative method yields the most accurate results, whereas displacement extrapolation is the easiest method to implement and still yields reasonable accuracy.

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Résumé On utilise les éléments en quadrilatère quart point dans diverses méthodes de calcul du facteur d'intensité de contrainte, afin de servir de guide pour le choix de la meilleure méthode. Il s'agit notamment des méthodes par extrapolation des déplacements, par calcul d'intégrale J ou d'énergie de Griffith, et par dérivée de la raideur. On considère trois géométries: une fissure centrale, une fissure de bord simple et deux fissures de bord dans une feuille rectangulaire. On observe pour ces trois cas que la méthode de la dérivée de la raideur conduit aux résultats les plus précis; par ailleurs, la méthode d'extrapolation des déplacements est la plus aisée à mettre en oeuvre et conduit néanmoins à une raisonnable exactitude.

     

The course of patients with suspected myocardial infarction. The identification of low-risk patients for early transfer from intensive care

The hospital course of all patients admitted to a medical intensive-care unit (ICU) with suspected myocardial infarction was reviewed to test the feasibility of identifying patients suitable for earlier transfer from the ICU. Three hundred sixty patients admitted after presentation with uncomplicated chest pain could be stratified into three risk groups within 24 hours of admission to the ICU. One hundred sixty-eight patients (47 per cent), who were without major complications, elevation of total serum creatine phosphokinase, or electrocardiographic evidence of transmural infarction during the first day, could be designated "low-risk" patients. Three per cent of the low-risk patients subsequently met clinical criteria for infarction, 2 percent had late complications in the ICU, and none died. Rates of infarction, late complications in the ICU, and mortality in the hospital were significantly higher for patients at intermediate and high risk. Identification of low-risk patients for whom early transfer may be routinely indicated is feasible and could reduce by 55 per cent the total number of days that such patients spend in the ICU.