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Publications

Publications by CSE

2012

Comparison of co-authorship networks across scientific fields using motifs

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

Publication
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

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

Publication
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

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

Publication
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

Authors
Pacheco, H; Cunha, A;

Publication
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

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

Publication
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.

2011

Differences in internet and LMS usage: A case study in higher education

Authors
Babo, R; Rodrigues, AC; Lopes, CT; de Oliveira, PC; Queiros, R; Pinto, M;

Publication
Higher Education Institutions and Learning Management Systems: Adoption and Standardization

Abstract
The Internet plays an important role in higher education institutions where Learning Management Systems (LMS) occupies a main role in the eLearning realm. In this chapter we aim to characterize the Internet and LMS usage patterns and their role in the largest Portuguese Polytechnic Institute. The usage patterns were analyzed in two components: characterization of Internet usage and the role of Internet and LMS in education. Using a quantitative approach, the data analysis describes the differences between gender, age and scientific fields. The carried qualitative analysis allows a better understanding of students' both motivations, opinions and suggestions of improvement. The outcome of this work is the presentation of the Portuguese students' profile regarding Internet and LMS usage patterns. We expect that these results can be used to select the most suitable digital pedagogical processes and tools to be adopted regarding the learning process and most adequate LMS's policies. © 2012, IGI Global.

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