Tiago da Silva

User-Centered Design and Agile Methods: A Systematic Review

This paper presents the results of a systematic review of existing literature on the integration of agile software development with user-centered design approaches. It shows that a common process model underlies such approaches and discusses which artifacts are used to support the collaboration between designers and developers.

Software effort prediction: a hyper-heuristic decision-tree based approach

Software effort prediction is an important task within software engineering. In particular, machine learning algorithms have been widely-employed to this task, bearing in mind their capability of providing accurate predictive models for the analysis of project stakeholders. Nevertheless, none of these algorithms has become the de facto standard for metrics prediction given the particularities of different software projects. Among these intelligent strategies, decision trees and evolutionary algorithms have been continuously employed for software metrics prediction, though mostly independent from each other. A recent work has proposed evolving decision trees through an evolutionary algorithm, and applying the resulting tree in the context of software maintenance effort prediction. In this paper, we raise the search-space level of an evolutionary algorithm by proposing the evolution of a decision-tree algorithm instead of the decision tree itself --- an approach known as hyper-heuristic. Our findings show that the decision-tree algorithm automatically generated by a hyper-heuristic is capable of statistically outperforming state-of-the-art top-down and evolution-based decision-tree algorithms, as well as traditional logistic regression. The ability of generating a highly-accurate comprehensible predictive model is crucial in software projects, considering that it allows the stakeholder to properly manage the teams resources with an improved confidence in the model predictions.

Ten Lessons Learned from Integrating Interaction Design and Agile Development

Agile development have a distinct culture that at first glance seems to conflict with Interaction Design. Therefore, integrating these two areas becomes a challenging task. There is little guidance about integrating them. Very limited empirical evidence exists on Agile development and Interaction Design being combined in practice. In order to better understand how these approaches are combined in practice, a multiple-case study of Agile teams working with Interaction Designers was performed. In the paper, we present a set of ten lessons learned from these studies.

Agile Usability Patterns for UCD Early Stages

The integration between agile methods and UCD has been addressed by several authors in recent years. However, a gap remains regarding how the practices have been described, lacking a standard that both designers and agile practitioners can understand and apply.

AGILEUX Model: Towards a Reference Model on Integrating UX in Developing Software Using Agile Methodologies

This paper presents a maturity model for integrating agile methods and user experience in the software development cycle that may be suitable for small companies. The proposal is in line with CMMI, MPS. BR and ISO18529. The model focuses on the first level of maturity where seeks to establish a standard process within an organization by defining agile practices, principles, techniques and artifacts of user experience. It also offers guidelines on how to integrate practices that are important for the evolution of maturity in order to evolve to more advanced levels. The preliminary model was verified by panels of experts. Future studies will be conducted so as to extend the model and do so by detailing other process levels and conducting action research at companies with experience in the maturation of process of integrating user experience into the software development cycle with CMMI and/or MPS. BR certifications.

lnterleukin-8 gene polymorphism and susceptibility to gastric cancer in a Brazilian population.

BACKGROUND Studies have demonstrated that some polymorphisms in different interleukin genes may increase the risk of cancer. The aim of this study was to investigate the association between the IL-8 (rs4073) -251A/T gene polymorphism and the risk of gastric cancer (GC). PATIENTS AND METHODS A case-control study was conducted on patients with noncardia gastric cancer. DNA was extracted from leukocytes and the IL-8 (rs4073) -251A/T polymorphism was analyzed by PCR-RFLP. Infection with Helicobacter pylori was investigated in the serum by ELISA. RESULTS The sample consisted of 104 patients with GC and 196 controls. Cigarette smoking (P=0.007) and high fat intake (P=0.01) were more frequent in patients with GC. The proportion of patients infected with H. pylori was similar in the two groups (P=0.101). The frequency of the genotype A/T was higher in the cancer group (P=0.008). An increased risk of GC was found in subjects carrying the genotype A/T (OR=2.50, CI: 1.27-4.90), subjects with high fat intake (OR=1.92, CI: 1.17-3.15), and smokers (OR=2.00, CI: 1.203.31). CONCLUSIONS Subjects with the heterozygous A/T genotype, high fat intake and smokers or ex-smokers presented an increased risk of GC. Individuals with A/A genotype may have protective effect for GC.

Understanding the UX designer's role within agile teams

User-Centered Design spends a considerable effort on research and analysis before development begins. On the other hand, Agile methods strive to deliver small sets of software features to customers as fast as possible in short iterations. Whereas the two methodologies have tensions regarding requirements gathering and upfront design, they also share similarities. For instance, both approaches are iterative and customer focused. However, there is little guidance on how to integrate these two perspectives and a lack of understanding with respect to the User Experience (UX) Designers role in an agile environment. Based on four ethnographically-informed studies in two large companies, we aim at providing a better understanding of the integration of Agile development and UX Design by describing the different roles that a UX Designer plays within an Agile environment.

Usability Evaluation Practices within Agile Development

Despite having different underlying concepts, agile methods and User-Centered Design aim ultimately at producing high quality software. Aiming at providing better understanding on how usability evaluation is addressed within agile environments, we carried out multiple-case studies in two large IT companies. On the one hand, our studies corroborate the literature with regards to the execution of usability inspection evaluations on lightweight prototypes, taking advantage of the iterative nature of Agile. On the other hand, we observed contrary to the literature that this iterative nature of Agile has not facilitated the execution of user testing sessions. Furthermore, we noticed that it is extremely difficult to perform traditional user testing sessions due to the tight schedules inherent to Agile. Finally, we describe a set of practices that can help improve specific artifacts in different stages of an agile process in order to successfully evaluate software product usability.

Association between the C3435T single-nucleotide polymorphism of multidrug resistance 1 gene and risk of gastric cancer

The multidrug resistance 1 (MDR1) gene encodes P-glycoprotein, which confers resistance to antineoplastic drugs, but also affects the kinetic disposition of certain drugs and carcinogens. The C3435T polymorphism of the MDR1 gene may influence the transport and excretion of carcinogens, increasing the risk of cancer. The aim of this study was to evaluate the association between this polymorphism and the risk of gastric cancer (GC). Ninety-eight patients with non-cardia GC and 203 healthy subjects participated in the study. DNA was extracted from leukocytes and the MDR1 polymorphism was analyzed using PCR-RFLP. Serology was performed by ELISA for the investigation of infection with Helicobacter pylori. No significant difference in the genotype (p=0.668) or allele (p=0.745) frequency of the C3435T polymorphism was observed between the GC and control groups. There was no association between the genotypes studied and the risk of GC in patients infected with H. pylori (p=0.662). Patient survival was not correlated with the genotypes studied (p=0.454). No correlation was observed between the C3435T polymorphism of the MDR1 gene and GC risk or prognosis in the population studied.

A grammatical evolution approach for software effort estimation

Software effort estimation is an important task within software engineering. It is widely used for planning and monitoring software project development as a means to deliver the product on time and within budget. Several approaches for generating predictive models from collected metrics have been proposed throughout the years. Machine learning algorithms, in particular, have been widely-employed to this task, bearing in mind their capability of providing accurate predictive models for the analysis of project stakeholders. In this paper, we propose a grammatical evolution approach for software metrics estimation. Our novel algorithm, namely SEEGE, is empirically evaluated on public project data sets, and we compare its performance with state-of-the-art machine learning algorithms such as support vector machines for regression and artificial neural networks, and also to popular linear regression. Results show that SEEGE outperforms the other algorithms considering three different evaluation measures, clearly indicating its effectiveness for the effort estimation task.