Filtro Schen-Castan (ISEF) para detecção de borda.

Com esta publicação, dá-se prosseguimento na implementação de algoritmos úteis para a detecção de bordas, atividade importante também no campo de visão por computador. O objetivo maior dessas implementações é a constituição de uma biblioteca de processamento de imagens em Java, como software livre, sob a General Public License - GNU, conforme publicada pela Free Software Foundation. Todas as implementações encontram-se disponíveis no diretório da Rede Agrolivre ().

Manual do Sistema Bife de Qualidade: verão 1.0.

O presente trabalho foi elaborado a fim de que os usuários que utilizam o Sistema Bife de Qualidade pudessem consultar um manual de uso das ferramentas do sistema sempre que tivessem dúvidas em relação ao uso do mesmo. A vantagem de um manual de uso é que se consegue explicitar as principais funcionalidades do sistema sem exibir, no entanto, um texto abrangente e cansativo de ser lido. As diversas informações obtidas durante o desenvolvimento do sistema, tais como as coletadas em entrevistas com os principais usuários do sistema, foram consideradas na elaboração deste trabalho. Sendo assim, o objetivo do manual é reunir, de forma clara e objetiva, todas as funcionalidades fornecidas pelo Sistema Bife de Qualidade, de tal modo que os usuários possam encontrar instruções para interagir facilmente com cada uma das funcionalidades apresentadas.

Design and implementation of robust systems for secure malware detection

Malicious software (malware) have significantly increased in terms of number and effectiveness during the past years. Until 2006, such software were mostly used to disrupt network infrastructures or to show coders’ skills. Nowadays, malware constitute a very important source of economical profit, and are very difficult to detect. Thousands of novel variants are released every day, and modern obfuscation techniques are used to ensure that signature-based anti-malware systems are not able to detect such threats. This tendency has also appeared on mobile devices, with Android being the most targeted platform. To counteract this phenomenon, a lot of approaches have been developed by the scientific community that attempt to increase the resilience of anti-malware systems. Most of these approaches rely on machine learning, and have become very popular also in commercial applications. However, attackers are now knowledgeable about these systems, and have started preparing their countermeasures. This has lead to an arms race between attackers and developers. Novel systems are progressively built to tackle the attacks that get more and more sophisticated. For this reason, a necessity grows for the developers to anticipate the attackers’ moves. This means that defense systems should be built proactively, i.e., by introducing some security design principles in their development. The main goal of this work is showing that such proactive approach can be employed on a number of case studies. To do so, I adopted a global methodology that can be divided in two steps. First, understanding what are the vulnerabilities of current state-of-the-art systems (this anticipates the attacker’s moves). Then, developing novel systems that are robust to these attacks, or suggesting research guidelines with which current systems can be improved. This work presents two main case studies, concerning the detection of PDF and Android malware. The idea is showing that a proactive approach can be applied both on the X86 and mobile world. The contributions provided on this two case studies are multifolded. With respect to PDF files, I first develop novel attacks that can empirically and optimally evade current state-of-the-art detectors. Then, I propose possible solutions with which it is possible to increase the robustness of such detectors against known and novel attacks. With respect to the Android case study, I first show how current signature-based tools and academically developed systems are weak against empirical obfuscation attacks, which can be easily employed without particular knowledge of the targeted systems. Then, I examine a possible strategy to build a machine learning detector that is robust against both empirical obfuscation and optimal attacks. Finally, I will show how proactive approaches can be also employed to develop systems that are not aimed at detecting malware, such as mobile fingerprinting systems. In particular, I propose a methodology to build a powerful mobile fingerprinting system, and examine possible attacks with which users might be able to evade it, thus preserving their privacy. To provide the aforementioned contributions, I co-developed (with the cooperation of the researchers at PRALab and Ruhr-Universität Bochum) various systems: a library to perform optimal attacks against machine learning systems (AdversariaLib), a framework for automatically obfuscating Android applications, a system to the robust detection of Javascript malware inside PDF files (LuxOR), a robust machine learning system to the detection of Android malware, and a system to fingerprint mobile devices. I also contributed to develop Android PRAGuard, a dataset containing a lot of empirical obfuscation attacks against the Android platform. Finally, I entirely developed Slayer NEO, an evolution of a previous system to the detection of PDF malware. The results attained by using the aforementioned tools show that it is possible to proactively build systems that predict possible evasion attacks. This suggests that a proactive approach is crucial to build systems that provide concrete security against general and evasion attacks.

Roll Project Rich Vehicle Routing benchmark problems.

This document describes a large set of Benchmark Problem Instances for the Rich Vehicle Routing Problem. All files are supplied as a single compressed (zipped) archive containing the instances, in XML format, an Object-Oriented Model supplied in XSD format, documentation and an XML parser written in Java to ease use.

Debugging: the good, the bad, and the quirky -- a qualitative analysis of novices' strategies

Murphy, L., Lewandowski, G., McCauley, R., Simon, B., Thomas, L., and Zander, C. 2008. Debugging: the good, the bad, and the quirky -- a qualitative analysis of novices' strategies. SIGCSE Bull. 40, 1 (Feb. 2008), 163-167

But consciousness isn't everything.

Comments on an article entitled `No Good News for DATA,' by Norman Lillegard in the Spring 1994 issue of `Cross Currents' magazine. Lillegard's stand that the android Commander Data in `Star Trek' fails to satisfy the biblical conception of persons; Lillegard's presentation of models that espouse functionalist theories of mind; Views of the essence of the human person.

Some Considerations on a Calculus with Weak References

Weak references are references that do not prevent the object they point to from being garbage collected. Most realistic languages, including Java, SML/NJ, and OCaml to name a few, have some facility for programming with weak references. Weak references are used in implementing idioms like memoizing functions and hash-consing in order to avoid potential memory leaks. However, the semantics of weak references in many languages are not clearly specified. Without a formal semantics for weak references it becomes impossible to prove the correctness of implementations making use of this feature. Previous work by Hallett and Kfoury extends λgc, a language for modeling garbage collection, to λweak, a similar language with weak references. Using this previously formalized semantics for weak references, we consider two issues related to well-behavedness of programs. Firstly, we provide a new, simpler proof of the well-behavedness of the syntactically restricted fragment of λweak defined previously. Secondly, we give a natural semantic criterion for well-behavedness much broader than the syntactic restriction, which is useful as principle for programming with weak references. Furthermore we extend the result, proved in previously of λgc, which allows one to use type-inference to collect some reachable objects that are never used. We prove that this result holds of our language, and we extend this result to allow the collection of weakly-referenced reachable garbage without incurring the computational overhead sometimes associated with collecting weak bindings (e.g. the need to recompute a memoized function). Lastly we use extend the semantic framework to model the key/value weak references found in Haskell and we prove the Haskell is semantics equivalent to a simpler semantics due to the lack of side-effects in our language.

A Formal Semantics for Weak References

A weak reference is a reference to an object that is not followed by the pointer tracer when garbage collection is called. That is, a weak reference cannot prevent the object it references from being garbage collected. Weak references remain a troublesome programming feature largely because there is not an accepted, precise semantics that describes their behavior (in fact, we are not aware of any formalization of their semantics). The trouble is that weak references allow reachable objects to be garbage collected, therefore allowing garbage collection to influence the result of a program. Despite this difficulty, weak references continue to be used in practice for reasons related to efficient storage management, and are included in many popular programming languages (Standard ML, Haskell, OCaml, and Java). We give a formal semantics for a calculus called λweak that includes weak references and is derived from Morrisett, Felleisen, and Harper’s λgc. λgc formalizes the notion of garbage collection by means of a rewrite rule. Such a formalization is required to precisely characterize the semantics of weak references. However, the inclusion of a garbage-collection rewrite-rule in a language with weak references introduces non-deterministic evaluation, even if the parameter-passing mechanism is deterministic (call-by-value in our case). This raises the question of confluence for our rewrite system. We discuss natural restrictions under which our rewrite system is confluent, thus guaranteeing uniqueness of program result. We define conditions that allow other garbage collection algorithms to co-exist with our semantics of weak references. We also introduce a polymorphic type system to prove the absence of erroneous program behavior (i.e., the absence of “stuck evaluation”) and a corresponding type inference algorithm. We prove the type system sound and the inference algorithm sound and complete.

Extending snBench to Support Hierarchical and Configurable Scheduling

It is useful in systems that must support multiple applications with various temporal requirements to allow application-specific policies to manage resources accordingly. However, there is a tension between this goal and the desire to control and police possibly malicious programs. The Java-based Sensor Execution Environment (SXE) in snBench presents a situation where such considerations add value to the system. Multiple applications can be run by multiple users with varied temporal requirements, some Real-Time and others best effort. This paper outlines and documents an implementation of a hierarchical and configurable scheduling system with which different applications can be executed using application-specific scheduling policies. Concurrently the system administrator can define fairness policies between applications that are imposed upon the system. Additionally, to ensure forward progress of system execution in the face of malicious or malformed user programs, an infrastructure for execution using multiple threads is described.

A cycle route planner mobile-app for Dublin city

In a road network, cyclists are the group exposed to the maximum amount of risk. Route choice of a cyclist is often based on level of expertise, perceived or actual road risks, personal decisions, weather conditions and a number of other factors. Consequently, cycling tends to be the only significant travel mode where optimised route choice is not based on least-path or least-time. This paper presents an Android platform based mobile-app for personalised route planning of cyclists in Dublin. The mobile-app, apart from its immediate advantage to the cyclists, acts as the departure point for a number of research projects and aids in establishing some critical calibration values for the cycling network in Dublin. 

Desarrollo de situaciones de aprendizaje en un escenario a distancia incorporando objetos virtuales de aprendizaje

Al introducir las nuevas tecnologías a los escenarios escolares se provocan reacciones (Chevallard, 1992) debido a que altera la armonía del Sistema Didáctico (el cual está compuesto por tres componentes; estudiantes, profesor y el saber). La relación entre los componentes del sistema didáctico se modifican debido a que existe un instrumento mediador que participa transformando las prácticas. Este proceso de integración requiere establecer las condiciones de equilibrio del Sistema Didáctico, al replantear el dominio del conocimiento, al caracterizar la interacción entre los estudiantes y el profesor, al ubicar el papel de la tecnología en el currículo, Laborde, (2001) y desde la perspectiva socioepistemológica, (Cantoral, 2004; Castañeda, 2004) explicar cómo se modifican las prácticas y cómo se construyen nuevos escenarios para el estudio de las matemáticas. Este trabajo de investigación propone describir las prácticas asociadas al estudio de la derivada en un ambiente tecnológico en las que se ponen en juego diversas situaciones interrelacionadas utilizando objetos java. Estos objetos, cuyo escenario natural de aplicación es en la red de Internet, se caracterizan por la disponibilidad de manipulación.

¿Cómo evaluar expresiones matemáticas en el computador?

En este artículo se muestra una forma de programar un evaluador de expresiones matemáticas en JAVA. El programa se construye paso a paso y se explican detalladamente las partes más importantes del mismo. El evaluador consta de dos partes o módulos, el primero se encarga de convertir la expresión digitada a notación postfija que es más sencilla para el computador; el segundo es el que evalúa la expresión que se obtuvo en un valor específico. Para poder comprender y reescribir este programa se necesita tener conocimientos básicos en la programación en JAVA, sin embargo, se explicará el uso de varias primitivas utilizadas y de algunos conceptos básicos de programación.

SOFT – generating highly flexible object code from XML specifications

Many code generation tools exist to aid developers in carrying out common mappings, such as from Object to XML or from Object to relational database. Such generated code tends to possess a high binding between the Object code and the target mapping, making integration into a broader application tedious or even impossible. In this paper we suggest XML technologies and the multiple inheritance capabilities of interface based languages such as Java, offer a means to unify such executable specifications, thus building complete, consistent and useful object models declaratively, without sacrificing component flexibility.

RAGE Architecture for Reusable Serious Gaming Technology Components

For seizing the potential of serious games, the RAGE project - funded by the Horizon-2020 Programme of the European Commission - will make available an interoperable set of advanced technology components (software assets) that support game studios at serious game development. This paper describes the overall software architecture and design conditions that are needed for the easy integration and reuse of such software assets in existing game platforms. Based on the component-based software engineering paradigm the RAGE architecture takes into account the portability of assets to different operating systems, different programming languages and different game engines. It avoids dependencies on external software frameworks and minimizes code that may hinder integration with game engine code. Furthermore it relies on a limited set of standard software patterns and well-established coding practices. The RAGE architecture has been successfully validated by implementing and testing basic software assets in four major programming languages (C#, C++, Java and Typescript/JavaScript, respectively). A demonstrator implementation of asset integration with an existing game engine was created and validated. The presented RAGE architecture paves the way for large scale development and application of cross-engine reusable software assets for enhancing the quality and diversity of serious gaming.

Operational monitoring and forecasting of bathing water quality through exploiting satellite Earth observation and models: The AlgaRisk demonstration service

Coastal zones and shelf-seas are important for tourism, commercial fishing and aquaculture. As a result the importance of good water quality within these regions to support life is recognised worldwide and a number of international directives for monitoring them now exist. This paper describes the AlgaRisk water quality monitoring demonstration service that was developed and operated for the UK Environment Agency in response to the microbiological monitoring needs within the revised European Union Bathing Waters Directive. The AlgaRisk approach used satellite Earth observation to provide a near-real time monitoring of microbiological water quality and a series of nested operational models (atmospheric and hydrodynamic-ecosystem) provided a forecast capability. For the period of the demonstration service (2008–2013) all monitoring and forecast datasets were processed in near-real time on a daily basis and disseminated through a dedicated web portal, with extracted data automatically emailed to agency staff. Near-real time data processing was achieved using a series of supercomputers and an Open Grid approach. The novel web portal and java-based viewer enabled users to visualise and interrogate current and historical data. The system description, the algorithms employed and example results focussing on a case study of an incidence of the harmful algal bloom Karenia mikimotoi are presented. Recommendations and the potential exploitation of web services for future water quality monitoring services are discussed.