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Publicações

Publicações por CSE

2012

Orchestration of E-Learning Services for Automatic Evaluation of Programming Exercises

Autores
Queiros, R; Leal, JP;

Publicação
JOURNAL OF UNIVERSAL COMPUTER SCIENCE

Abstract
Managing programming exercises require several heterogeneous systems such as evaluation engines, learning objects repositories and exercise resolution environments. The coordination of networks of such disparate systems is rather complex. These tools would be too specific to incorporate in an e-Learning platform. Even if they could be provided as pluggable components, the burden of maintaining them would be prohibitive to institutions with few courses in those domains. This work presents a standard based approach for the coordination of a network of e-Learning systems participating on the automatic evaluation of programming exercises. The proposed approach uses a pivot component to orchestrate the interaction among all the systems using communication standards. This approach was validated through its effective use on classroom and we present some preliminary results.

2012

Comparison of co-authorship networks across scientific fields using motifs

Autores
Choobdar, S; Ribeiro, P; Bugla, S; Silva, F;

Publicação
2012 IEEE/ACM INTERNATIONAL CONFERENCE ON ADVANCES IN SOCIAL NETWORKS ANALYSIS AND MINING (ASONAM)

Abstract
Comparing scientific production across different fields of knowledge is commonly controversial and subject to disagreement. Such comparisons are often based on quantitative indicators, such as papers per researcher, and data normalization is very difficult to accomplish. Different approaches can provide new insight and in this paper we focus on the comparison of different scientific fields based on their research collaboration networks. We use co-authorship networks where nodes are researchers and the edges show the existing co-authorship relations between them. Our comparison methodology is based on network motifs, which are over represented patterns, or subgraphs. We derive motif fingerprints for 22 scientific fields based on 29 different small motifs found in the corresponding co-authorship networks. These fingerprints provide a metric for assessing similarity among scientific fields, and our analysis shows that the discrimination power of the 29 motif types is not identical. We use a co-authorship dataset built from over 15,361 publications inducing a co-authorship network with over 32,842 researchers. Our results also show that we can group different fields according to their fingerprints, supporting the notion that some fields present higher similarity and can be more easily compared.

2012

Delta Lenses over Inductive Types

Autores
Pacheco, H; Cunha, A; Hu, Z;

Publicação
ECEASST

Abstract
Existing bidirectional languages are either state-based or operation-based, depending on whether they represent updates as mere states or as sequences of edit operations. In-between both worlds are delta-based frameworks, where updates are represented using alignment relationships between states. In this paper, we formalize delta lenses over inductive types using dependent type theory and develop a point-free delta lens language with an explicit separation of shape and data. In contrast with the already known issue of data alignment, we identify the new problem of shape alignment and solve it by lifting standard recursion patterns such as folds and unfolds to delta lenses that use alignment to infer meaningful shape updates. © Bidirectional Transformations 2012.

2012

Relations as Executable Specifications: Taming Partiality and Non-determinism Using Invariants

Autores
Macedo, N; Pacheco, H; Cunha, A;

Publicação
Relational and Algebraic Methods in Computer Science - 13th International Conference, RAMiCS 2012, Cambridge, UK, September 17-20, 2012. Proceedings

Abstract
The calculus of relations has been widely used in program specification and reasoning. It is very tempting to use such specifications as running prototypes of the desired program, but, even considering finite domains, the inherent partiality and non-determinism of relations makes this impractical and highly inefficient. To tame partiality we prescribe the usage of invariants, represented by coreflexives, to characterize the exact domains and codomains of relational specifications. Such invariants can be used as pre-condition checkers to avoid runtime errors. Moreover, we show how such invariants can be used to narrow the non-deterministic execution of relational specifications, making it viable for a relevant class of problems. In particular, we show how the proposed techniques can be applied to execute specifications of bidirectional transformations, a domain where partiality and non-determinism are paramount. © 2012 Springer-Verlag.

2012

Multifocal: A Strategic Bidirectional Transformation Language for XML Schemas

Autores
Pacheco, H; Cunha, A;

Publicação
Theory and Practice of Model Transformations - 5th International Conference, ICMT 2012, Prague, Czech Republic, May 28-29, 2012. Proceedings

Abstract
Lenses are one of the most popular approaches to define bidirectional transformations between data models. However, writing a lens transformation typically implies describing the concrete steps that convert values in a source schema to values in a target schema. In contrast, many XML-based languages allow writing structure-shy programs that manipulate only specific parts of XML documents without having to specify the behavior for the remaining structure. In this paper, we propose a structure-shy bidirectional two-level transformation language for XML Schemas, that describes generic type-level transformations over schema representations coupled with value-level bidirectional lenses for document migration. When applying these two-level programs to particular schemas, we employ an existing algebraic rewrite system to optimize the automatically-generated lens transformations, and compile them into Haskell bidirectional executables. We discuss particular examples involving the generic evolution of recursive XML Schemas, and compare their performance gains over non-optimized definitions. © 2012 Springer-Verlag.

2012

Innovations in XML applications and metadata management: Advancing technologies

Autores
Ramalho, JC; Simoes, A; Queiros, R;

Publicação
Innovations in XML Applications and Metadata Management: Advancing Technologies

Abstract
As new concepts such as virtualization, cloud computing, and web applications continue to emerge, XML has begun to assume the role as the universal language for communication among contrasting systems that grow throughout the internet. Innovations in XML Applications and Metadata Management: Advancing Technologies addresses the functionality between XML and its related technologies towards application development based on previous concepts. This book aims to highlights the variety of purposes for XML applications and how the technology development brings together advancements in the virtual world.

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