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Dive into the research topics where Diogo R. Ferreira is active.

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Featured researches published by Diogo R. Ferreira.


business process management | 2012

Process Mining Manifesto

Wil M. P. van der Aalst; A Arya Adriansyah; Ana Karla Alves de Medeiros; Franco Arcieri; Thomas Baier; Tobias Blickle; R. P. Jagadeesh Chandra Bose; Peter van den Brand; Ronald Brandtjen; Joos C. A. M. Buijs; Andrea Burattin; Josep Carmona; Malu Castellanos; Jan Claes; Jonathan E. Cook; Nicola Costantini; Francisco Curbera; Ernesto Damiani; Massimiliano de Leoni; Pavlos Delias; Boudewijn F. van Dongen; Marlon Dumas; Schahram Dustdar; Dirk Fahland; Diogo R. Ferreira; Walid Gaaloul; Frank van Geffen; Sukriti Goel; Cw Christian Günther; Antonella Guzzo

Process mining techniques are able to extract knowledge from event logs commonly available in today’s information systems. These techniques provide new means to discover, monitor, and improve processes in a variety of application domains. There are two main drivers for the growing interest in process mining. On the one hand, more and more events are being recorded, thus, providing detailed information about the history of processes. On the other hand, there is a need to improve and support business processes in competitive and rapidly changing environments. This manifesto is created by the IEEE Task Force on Process Mining and aims to promote the topic of process mining. Moreover, by defining a set of guiding principles and listing important challenges, this manifesto hopes to serve as a guide for software developers, scientists, consultants, business managers, and end-users. The goal is to increase the maturity of process mining as a new tool to improve the (re)design, control, and support of operational business processes.


ubiquitous computing | 2010

Preprocessing techniques for context recognition from accelerometer data

Davide Figo; Pedro C. Diniz; Diogo R. Ferreira; João M. P. Cardoso

The ubiquity of communication devices such as smartphones has led to the emergence of context-aware services that are able to respond to specific user activities or contexts. These services allow communication providers to develop new, added-value services for a wide range of applications such as social networking, elderly care and near-emergency early warning systems. At the core of these services is the ability to detect specific physical settings or the context a user is in, using either internal or external sensors. For example, using built-in accelerometers, it is possible to determine whether a user is walking or running at a specific time of day. By correlating this knowledge with GPS data, it is possible to provide specific information services to users with similar daily routines. This article presents a survey of the techniques for extracting this activity information from raw accelerometer data. The techniques that can be implemented in mobile devices range from classical signal processing techniques such as FFT to contemporary string-based methods. We present experimental results to compare and evaluate the accuracy of the various techniques using real data sets collected from daily activities.


Information Systems | 2012

Business process analysis in healthcare environments: A methodology based on process mining

Álvaro Rebuge; Diogo R. Ferreira

Performing business process analysis in healthcare organizations is particularly difficult due to the highly dynamic, complex, ad hoc, and multi-disciplinary nature of healthcare processes. Process mining is a promising approach to obtain a better understanding about those processes by analyzing event data recorded in healthcare information systems. However, not all process mining techniques perform well in capturing the complex and ad hoc nature of clinical workflows. In this work we introduce a methodology for the application of process mining techniques that leads to the identification of regular behavior, process variants, and exceptional medical cases. The approach is demonstrated in a case study conducted at a hospital emergency service. For this purpose, we implemented the methodology in a tool that integrates the main stages of process analysis. The tool is specific to the case study, but the same methodology can be used in other healthcare environments.


business process management | 2007

Approaching process mining with sequence clustering: experiments and findings

Diogo R. Ferreira; Marielba Zacarias; Miguel Malheiros; Pedro Ferreira

Sequence clustering is a technique of bioinformatics that is used todiscover the properties of sequences by grouping them into clusters and assigningeach sequence to one of those clusters. In business process mining, the goal is alsoto extract sequence behaviour from an event log but the problem is oftensimplified by assuming that each event is already known to belong to a givenprocess and process instance. In this paper, we describe two experiments wherethis information is not available. One is based on a real-world case study ofobserving a software development team for three weeks. The other is based onsimulation and shows that it is possible to recover the original behaviour in a fullyautomated way. In both experiments, sequence clustering plays a central role.


business process management | 2009

Discovering Process Models from Unlabelled Event Logs

Diogo R. Ferreira; Daniel Gillblad

Existing process mining techniques are able to discover process models from event logs where each event is known to have been produced by a given process instance. In this paper we remove this restriction and address the problem of discovering the process model when the event log is provided as an unlabelled stream of events. Using a probabilistic approach, it is possible to estimate the model by means of an iterative Expectaction---Maximization procedure. The same procedure can be used to find the case id in unlabelled event logs. A series of experiments show how the proposed technique performs under varying conditions and in the presence of certain workflow patterns. Results are presented for a running example based on a technical support process.


Pervasive and Mobile Computing | 2010

Providing user context for mobile and social networking applications

André C. Santos; João M. P. Cardoso; Diogo R. Ferreira; Pedro C. Diniz; Paulo Chainho

The processing capabilities of mobile devices coupled with portable and wearable sensors provide the basis for new context-aware services and applications tailored to the user environment and daily activities. In this article, we describe the approach developed within the UPCASE project, which makes use of sensors available in the mobile device as well as sensors externally connected via Bluetooth to provide user contexts. We describe the system architecture from sensor data acquisition to feature extraction, context inference and the publication of context information in web-centered servers that support well-known social networking services. In the current prototype, context inference is based on decision trees to learn and to identify contexts dynamically at run-time, but the middleware allows the integration of different inference engines if necessary. Experimental results in a real-world setting suggest that the proposed solution is a promising approach to provide user context to local mobile applications as well as to network-level applications such as social networking services.


business process management | 2009

Understanding Spaghetti Models with Sequence Clustering for ProM

Gabriel M. Veiga; Diogo R. Ferreira

The goal of process mining is to discover process models from event logs. However, for processes that are not well structured and have a lot of diverse behavior, existing process mining techniques generate highly complex models that are often difficult to understand; these are called spaghetti models. One way to try to understand these models is to divide the log into clusters in order to analyze reduced sets of cases. However, the amount of noise and ad-hoc behavior present in real-world logs still poses a problem, as this type of behavior interferes with the clustering and complicates the models of the generated clusters, affecting the discovery of patterns. In this paper we present an approach that aims at overcoming these difficulties by extracting only the useful data and presenting it in an understandable manner. The solution has been implemented in ProM and is divided in two stages: preprocessing and sequence clustering. We illustrate the approach in a case study where it becomes possible to identify behavioral patterns even in the presence of very diverse and confusing behavior.


International Journal of Cooperative Information Systems | 2006

AN INTEGRATED LIFE CYCLE FOR WORKFLOW MANAGEMENT BASED ON LEARNING AND PLANNING

Hugo M. Ferreira; Diogo R. Ferreira

The ability to describe business processes as executable models has always been one of the fundamental premises of workflow management. Yet, the tacit nature of human knowledge is often an obstacle to eliciting accurate process models. On the other hand, the result of process modeling is a static plan of action, which is difficult to adapt to changing procedures or to different business goals. In this article, we attempt to address these problems by approaching workflow management with a combination of learning and planning techniques. Assuming that processes cannot be fully described at build-time, we make use of learning techniques, namely Inductive Logic Programming (ILP), in order to discover workflow activities and to describe them as planning operators. These operators will be subsequently fed to a partial-order planner in order to find the process model as a planning solution. The continuous interplay between learning, planning and execution aims at arriving at a feasible plan by successive refinement of the operators. The approach is illustrated in two simple scenarios. Following a discussion of related work, the paper concludes by presenting the main challenges that remain to be solved.


mobile wireless middleware operating systems and applications | 2009

Context Inference for Mobile Applications in the UPCASE Project

André C. Santos; Luís Tarrataca; João M. P. Cardoso; Diogo R. Ferreira; Pedro C. Diniz; Paulo Chainho

The growing processing capabilities of mobile devices coupled with portable and wearable sensors have enabled the development of context-aware services tailored to the user environment and its daily activities. The problem of determining the user context at each particular point in time is one of the main challenges in this area. In this paper, we describe the approach pursued in the UPCASE project, which makes use of sensors available in the mobile device as well as sensors externally connected via Bluetooth. We describe the system architecture from raw data acquisition to feature extraction and context inference. As a proof of concept, the inference of contexts is based on a decision tree to learn and identify contexts automatically and dynamically at runtime. Preliminary results suggest that this is a promising approach for context inference in several application scenarios.


IEEE Journal on Selected Areas in Communications | 2014

Real-Time Network Coding for Live Streaming in Hyper-Dense WiFi Spaces

Diogo R. Ferreira; Rui A. Costa; João Barros

Consumer demand for high-quality video over wireless networks is increasing at fast pace. The resulting technical challenges are particularly stringent in crowded spaces, where the density of users far exceeds the ability to deploy cellular base stations or WiFi infrastructure in a cost effective way. To address this problem, we present a reliable and scalable live streaming solution based on wireless multicast with real-time network coding. At the core of our approach is a timely delivery scheme that uses a minimum amount of feedback from the receivers to generate coded repair packets that are simultaneously useful to a large number of users. Our protocol, which we implemented and tested in a real-world wireless testbed, differs from traditional wireless unicast and multicast schemes in that (a) the feedback messages of the users are treated jointly and (b) the repair mechanism considers both the playout deadlines of individual packets and the list of packets already received by the clients. In comparison with a standard video approach that sends an MPEG-2 encoded stream over 802.11 unicast links, our solution offers real-time guarantees for all users commensurate with the link quality and an 11x improvement in terms of bandwidth usage. A commercial version of the proposed solution shows a strong increase in the number of clients that can access video streams simultaneously over a single WiFi hotspot.

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Pedro C. Diniz

University of Southern California

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André C. Santos

Technical University of Lisbon

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Pedro Carvalho

Instituto Superior Técnico

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Barbara Weber

Technical University of Denmark

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Daniel Gillblad

Swedish Institute of Computer Science

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