Verification and FPGA circuits of a block-2 fast path-based predictor

This paper formally derives a new path-based neural branch prediction algorithm (FPP) into blocks of size two for a lower hardware solution while maintaining similar input-output characteristic to the algorithm. The blocked solution, here referred to as B2P algorithm, is obtained using graph theory and retiming methods. Verification approaches were exercised to show that prediction performances obtained from the FPP and B2P algorithms differ within one mis-prediction per thousand instructions using a known framework for branch prediction evaluation. For a chosen FPGA device, circuits generated from the B2P algorithm showed average area savings of over 25% against circuits for the FPP algorithm with similar time performances thus making the proposed blocked predictor superior from a practical viewpoint.

FPGA organization for the fast path-based neural branch predictor

This paper develops cycle-level FPGA circuits of an organization for a fast path-based neural branch predictor Our results suggest that practical sizes of prediction tables are limited to around 32 KB to 64 KB in current FPGA technology due mainly to FPGA area of logic resources to maintain the tables. However the predictor scales well in terms of prediction speed. Table sizes alone should not be used as the only metric for hardware budget when comparing neural-based predictor to predictors of totally different organizations. This paper also gives early evidence to shift the attention on to the recovery from mis-prediction latency rather than on prediction latency as the most critical factor impacting accuracy of predictions for this class of branch predictors.

Maximizing Resource Sharing in WDM Mesh Networks With Path-Based Protection and Sparse OEO Regeneration

We propose a resource-sharing scheme that supports three kinds of sharing scenarios in a WDM mesh network with path-based protection and sparse OEO regeneration. Several approaches are used to maximize the sharing of wavelength-links and OEO regenerators.

A path-based framework for analyzing large markov models

Reliability and dependability modeling can be employed during many stages of analysis of a computing system to gain insights into its critical behaviors. To provide useful results, realistic models of systems are often necessarily large and complex. Numerical analysis of these models presents a formidable challenge because the sizes of their state-space descriptions grow exponentially in proportion to the sizes of the models. On the other hand, simulation of the models requires analysis of many trajectories in order to compute statistically correct solutions. This dissertation presents a novel framework for performing both numerical analysis and simulation. The new numerical approach computes bounds on the solutions of transient measures in large continuous-time Markov chains (CTMCs). It extends existing path-based and uniformization-based methods by identifying sets of paths that are equivalent with respect to a reward measure and related to one another via a simple structural relationship. This relationship makes it possible for the approach to explore multiple paths at the same time,· thus significantly increasing the number of paths that can be explored in a given amount of time. Furthermore, the use of a structured representation for the state space and the direct computation of the desired reward measure (without ever storing the solution vector) allow it to analyze very large models using a very small amount of storage. Often, path-based techniques must compute many paths to obtain tight bounds. In addition to presenting the basic path-based approach, we also present algorithms for computing more paths and tighter bounds quickly. One resulting approach is based on the concept of path composition whereby precomputed subpaths are composed to compute the whole paths efficiently. Another approach is based on selecting important paths (among a set of many paths) for evaluation. Many path-based techniques suffer from having to evaluate many (unimportant) paths. Evaluating the important ones helps to compute tight bounds efficiently and quickly.

Split message-based anonymity for JXTA applications

JXTA is an open peer-to-peer (P2P) protocols specification that, in its about 10 years of history, has slowly evolved to appeal to a broad set of applications. As part of this process,some long awaited security improvements have been included in the latest versions. However, under some contexts, even more advanced security requirements should be met, such as anonymity. Several approaches exist to deploy anonymity in P2P networks, but no perfect solution exists. Even though path-based approaches are quite popular, it is considered that, in dynamicgroups, using a split message-based one is better. In this work, we propose an anonymity service for JXTA using such approach. The proposal takes advantage JXTA's core services, in a manner so that it can be easily integrated to existing end applications and services.

Payone : incentive for epidemic protocol-based anonymity system

Anonymity systems maintain the anonymity of communicating nodes by camouflaging them, either with peer nodes generating dummy traffic or with peer nodes participating in the actual communication process. The probability of any adversary breaking down the anonymity of the communicating nodes is inversely proportional to the number of peer nodes participating in the network. Hence to maintain the anonymity of the communicating nodes, a large number of peer nodes are needed. Lack of peer availability weakens the anonymity of any large scale anonymity system. This work proposes PayOne, an incentive based scheme for promoting peer availability. PayOne aims to increase the peer availability by encouraging nodes to participate in the anonymity system by awarding them with incentives and thereby promoting the anonymity strength. Existing incentive schemes are designed for single path based approaches. There is no incentive scheme for multipath based or epidemic based anonymity systems. This work has been specifically designed for epidemic protocols and has been implemented over MuON, one of the latest entries to the area of multicasting based anonymity systems. MuON is a peer-to-peer based anonymity system which uses epidemic protocol for data dissemination. Existing incentive schemes involve paying every intermediate node that is involved in the communication between the initiator and the receiver. These schemes are not appropriate for epidemic based anonymity systems due to the incurred overhead. PayOne differs from the existing schemes because it involves paying a single intermediate node that participates in the network. The intermediate node can be any random node that participates in the communication and does not necessarily need to lie in the communication path between the initiator and the receiver. The light-weight characteristics of PayOne make it viable for large-scale epidemic based anonymity systems.

A CMMI-compliant requirements management and development process

Requirements Engineering has been acknowledged an essential discipline for Software Quality. Poorly-defined processes for eliciting, analyzing, specifying and validating requirements can lead to unclear issues or misunderstandings on business needs and project’s scope. These typically result in customers’ non-satisfaction with either the products’ quality or the increase of the project’s budget and duration. Maturity models allow an organization to measure the quality of its processes and improve them according to an evolutionary path based on levels. The Capability Maturity Model Integration (CMMI) addresses the aforementioned Requirements Engineering issues. CMMI defines a set of best practices for process improvement that are divided into several process areas. Requirements Management and Requirements Development are the process areas concerned with Requirements Engineering maturity. Altran Portugal is a consulting company concerned with the quality of its software. In 2012, the Solution Center department has developed and applied successfully a set of processes aligned with CMMI-DEV v1.3, what granted them a Level 2 maturity certification. For 2015, they defined an organizational goal of addressing CMMI-DEV maturity level 3. This MSc dissertation is part of this organization effort. In particular, it is concerned with the required process areas that address the activities of Requirements Engineering. Our main goal is to contribute for the development of Altran’s internal engineering processes to conform to the guidelines of the Requirements Development process area. Throughout this dissertation, we started with an evaluation method based on CMMI and conducted a compliance assessment of Altran’s current processes. This allowed demonstrating their alignment with the CMMI Requirements Management process area and to highlight the improvements needed to conform to the Requirements Development process area. Based on the study of alternative solutions for the gaps found, we proposed a new Requirements Management and Development process that was later validated using three different approaches. The main contribution of this dissertation is the new process developed for Altran Portugal. However, given that studies on these topics are not abundant in the literature, we also expect to contribute with useful evidences to the existing body of knowledge with a survey on CMMI and requirements engineering trends. Most importantly, we hope that the implementation of the proposed processes’ improvements will minimize the risks of mishandled requirements, increasing Altran’s performance and taking them one step further to the desired maturity level.

Eutanásia ativa

Euthanasia, especially the active one, has always been an extremely discussed subject, which goes further pure dogmatics and transcends the strictly legal field. A reflection about such issue makes us re-think on what it implies for all the involved without ever loosing sight of the fact that admitting a legalization is, in a legal system as ours, to admit the lack of punishment of an homicide act or an assistance to suicide. However, burying in mind the foreign experiences, isn’t there a possibility of working on a path that respects both the basis of our legal system and the rest of the interests involved? And what interests would those be? How to admit such a path? Based on what assumptions? The present study proposes a discovery of paths and not the search for dead ends, creating definitive answers. The purpose of this dissertation is to explore the existing structure of the Portuguese legal system on these matters, in a path that is until now mostly in favour of punishment, based on homicide or assisted suicide crimes. Along with the Portuguese dynamic, we want to analyse legal systems that opted by decriminalization and, based on those experiences, shared with our legal culture, scan the viability of a decriminalization procedure. What paths would be viable for such a decriminalization in Portuguese criminal territory? The scope is only to open the eyes of who always wanted to keep them shut, or to who just never tried to open them, because at the end of the day it will always be a discussion that we want to keep light up, since that what we are here discussing is life. We want discussion, not imposition.

Routage adaptatif et qualité de service dans les réseaux optiques à commutation de rafales

Les réseaux optiques à commutation de rafales (OBS) sont des candidats pour jouer un rôle important dans le cadre des réseaux optiques de nouvelle génération. Dans cette thèse, nous nous intéressons au routage adaptatif et au provisionnement de la qualité de service dans ce type de réseaux. Dans une première partie de la thèse, nous nous intéressons à la capacité du routage multi-chemins et du routage alternatif (par déflection) à améliorer les performances des réseaux OBS, pro-activement pour le premier et ré-activement pour le second. Dans ce contexte, nous proposons une approche basée sur l’apprentissage par renforcement où des agents placés dans tous les nœuds du réseau coopèrent pour apprendre, continuellement, les chemins du routage et les chemins alternatifs optimaux selon l’état actuel du réseau. Les résultats numériques montrent que cette approche améliore les performances des réseaux OBS comparativement aux solutions proposées dans la littérature. Dans la deuxième partie de cette thèse, nous nous intéressons au provisionnement absolu de la qualité de service où les performances pire-cas des classes de trafic de priorité élevée sont garanties quantitativement. Plus spécifiquement, notre objectif est de garantir la transmission sans pertes des rafales de priorité élevée à l’intérieur du réseau OBS tout en préservant le multiplexage statistique et l’utilisation efficace des ressources qui caractérisent les réseaux OBS. Aussi, nous considérons l’amélioration des performances du trafic best effort. Ainsi, nous proposons deux approches : une approche basée sur les nœuds et une approche basée sur les chemins. Dans l’approche basée sur les nœuds, un ensemble de longueurs d’onde est assigné à chaque nœud du bord du réseau OBS pour qu’il puisse envoyer son trafic garanti. Cette assignation prend en considération les distances physiques entre les nœuds du bord. En outre, nous proposons un algorithme de sélection des longueurs d’onde pour améliorer les performances des rafales best effort. Dans l’approche basée sur les chemins, le provisionnement absolu de la qualité de service est fourni au niveau des chemins entre les nœuds du bord du réseau OBS. À cette fin, nous proposons une approche de routage et d’assignation des longueurs d’onde qui a pour but la réduction du nombre requis de longueurs d’onde pour établir des chemins sans contentions. Néanmoins, si cet objectif ne peut pas être atteint à cause du nombre limité de longueurs d’onde, nous proposons de synchroniser les chemins en conflit sans le besoin pour des équipements additionnels. Là aussi, nous proposons un algorithme de sélection des longueurs d’onde pour les rafales best effort. Les résultats numériques montrent que l’approche basée sur les nœuds et l’approche basée sur les chemins fournissent le provisionnement absolu de la qualité de service pour le trafic garanti et améliorent les performances du trafic best effort. En outre, quand le nombre de longueurs d’ondes est suffisant, l’approche basée sur les chemins peut accommoder plus de trafic garanti et améliorer les performances du trafic best effort par rapport à l’approche basée sur les nœuds.

Context-sensitive analysis without calling-context

Since Sharir and Pnueli, algorithms for context-sensitivity have been defined in terms of 'valid' paths in an interprocedural flow graph. The definition of valid paths requires atomic call and ret statements, and encapsulated procedures. Thus, the resulting algorithms are not directly applicable when behavior similar to call and ret instructions may be realized using non-atomic statements, or when procedures do not have rigid boundaries, such as with programs in low level languages like assembly or RTL. We present a framework for context-sensitive analysis that requires neither atomic call and ret instructions, nor encapsulated procedures. The framework presented decouples the transfer of control semantics and the context manipulation semantics of statements. A new definition of context-sensitivity, called stack contexts, is developed. A stack context, which is defined using trace semantics, is more general than Sharir and Pnueli's interprocedural path based calling-context. An abstract interpretation based framework is developed to reason about stack-contexts and to derive analogues of calling-context based algorithms using stack-context. The framework presented is suitable for deriving algorithms for analyzing binary programs, such as malware, that employ obfuscations with the deliberate intent of defeating automated analysis. The framework is used to create a context-sensitive version of Venable et al.'s algorithm for analyzing x86 binaries without requiring that a binary conforms to a standard compilation model for maintaining procedures, calls, and returns. Experimental results show that a context-sensitive analysis using stack-context performs just as well for programs where the use of Sharir and Pnueli's calling-context produces correct approximations. However, if those programs are transformed to use call obfuscations, a contextsensitive analysis using stack-context still provides the same, correct results and without any additional overhead. © Springer Science+Business Media, LLC 2011.

Erudição e ciência: as procelas de Júlio Ribeiro no Brasil oitocentista

Pós-graduação em História - FCLAS

A hybrid method for large-scale short-term scheduling of make-and-pack production processes

Due to the ongoing trend towards increased product variety, fast-moving consumer goods such as food and beverages, pharmaceuticals, and chemicals are typically manufactured through so-called make-and-pack processes. These processes consist of a make stage, a pack stage, and intermediate storage facilities that decouple these two stages. In operations scheduling, complex technological constraints must be considered, e.g., non-identical parallel processing units, sequence-dependent changeovers, batch splitting, no-wait restrictions, material transfer times, minimum storage times, and finite storage capacity. The short-term scheduling problem is to compute a production schedule such that a given demand for products is fulfilled, all technological constraints are met, and the production makespan is minimised. A production schedule typically comprises 500–1500 operations. Due to the problem size and complexity of the technological constraints, the performance of known mixed-integer linear programming (MILP) formulations and heuristic approaches is often insufficient. We present a hybrid method consisting of three phases. First, the set of operations is divided into several subsets. Second, these subsets are iteratively scheduled using a generic and flexible MILP formulation. Third, a novel critical path-based improvement procedure is applied to the resulting schedule. We develop several strategies for the integration of the MILP model into this heuristic framework. Using these strategies, high-quality feasible solutions to large-scale instances can be obtained within reasonable CPU times using standard optimisation software. We have applied the proposed hybrid method to a set of industrial problem instances and found that the method outperforms state-of-the-art methods.

The 2011 Constitutional reform in Morocco: more flaws than merits. Jean Monnet Occasional Paper No. 07/2014

Introduction. In the speech given to both Houses of Parliament on 11 October 2013 during the first parliamentary session, King Mohammed VI said that the “Moroccan democratic model” was “a precursor in the region as well as on the continental level.”1 Similarly, with the purpose of stressing the “democratic exceptionalism”2 of the country, the new government, led by Abdeilah Benkirane, emphasised that Morocco represents a “third way” compared to countries such as Tunisia, Libya or Egypt since it “…has not embarked on a limited process of reform from the top, driven and controlled by the King. Nor has it experienced a revolution brought a angry citizens rising up against the regime. Rather, it has chosen an alternate path based on a genuine partnership between the King and the PJD (Parti de la justice et du développement) that promises to bring about more far-reaching reform than palace alone would grant, without the disruption caused by uncontrolled popular upheaval.”4 It should not be at all surprising that the regime and the new Government consider Morocco a “democratic model” or a “third way.” After all, they are refe country. What is harder to understand is that when discussing the Arab uprisings, even prominent Western political leaders, representatives of the European Union institutions and the mainstream media (when they do not forget about Morocc to praise the process of democratic reform carried out by Mohammed VI. For example, on 12 September 2012, Hillary Clinton, former US Secretary of State, said, “in many ways, the United States looks to Morocco to be a leader and a model […] On political reform, we have all seen remarkable changes taking place across North Africa and the Middle East. I commend Morocco and your government for your efforts to stay ahead of these changes by holding free and fair elections, empowering the elected parliament, taking other steps to ensure that the government reflects the will of the people.”5 Similarly, former French President Nicolas Sarkozy sang the praises of the process that led to the adoption of the new 2011 Constitution: “King Mohammed VI has shown the path towards a profound, peaceful and modern transformation of Moroccan institutions and society […] France fully supports this exemplary process.” Interestingly enough, even at the European Union level the constitutional reform that took more far-reaching reform than palace alone would grant, without the disruption caused by uncontrolled popular upheaval.”4 It should not be at all surprising that the regime and the new Government consider Morocco a “democratic model” or a “third way.” After all, they are refe country. What is harder to understand is that when discussing the Arab uprisings, even prominent Western political leaders, representatives of the European Union institutions and the mainstream media (when they do not forget about Morocc to praise the process of democratic reform carried out by Mohammed VI. For example, on 12 September 2012, Hillary Clinton, former US Secretary of State, said, “in many ways, the United States looks to Morocco to be a leader and a model […] On political reform, we have all seen remarkable changes taking place across North Africa and the Middle East. I commend Morocco and your government for your efforts to stay ahead of these changes by holding free and fair elections, empowering the elected parliament, taking other steps to ensure that the government reflects the will of the people.”5 Similarly, former French President Nicolas Sarkozy sang the praises of the process that led to the adoption of the new 2011 Constitution: “King Mohammed VI has shown the path towards a profound, peaceful and modern transformation of Moroccan institutions and society […] France fully supports this exemplary process.” Interestingly enough, even at the European Union level the constitutional reform that took place in Morocco was considered an extremely positive step taken by the country, as well as a means to strengthen the cooperation between the EU and Morocco. Indeed, according to the High Representative Catherine Ashton, this reform “constitute[s] a significant response to the legitimate aspirations of the Moroccan people and [is] consistent with Morocco’s Advanced Status with the EU.”7 When it comes to the media, it is worth noting that following the ratification of the 2011 Constitution, The New York Times headlined: “All Hail the (Democratic) King.” Even sections of the academic literature have commended the constitutional reform carried out by the Moroccan Sovereign.9 In this paper I argue against the aforementioned idea, according to which Morocco should be considered a model in the region, and in particular I show that the constitution-making process, the 2011 Constitution and its subsequent implementation have more flaws than merits. Accordingly, this paper proceeds in five steps. First of all, I examine the reaction of the regime to the upheavals that broke out in the country after 20 February 2011. Secondly, I analyse the process of constitution showing its main strengths and weaknesses, and comparing it with other constituent processes that took place in the region following the Arab uprisings. In the third section, I highlight the most significant elements of continuity and discontinuity with the previous 1996 Constitution. The fourth section deals with the process of implementation: specifically process is proceeding quite slowly and that in some cases ordinary legislation is in contrast with the new Constitution and international human rights treaties. Moreover, I discuss the role that the judiciary and the Constitutional Court can play in the implementation and interpretation of the Constitution. Finally, I draw some concluding remarks.

A learning approach to swarm-based path detection and tracking

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores