Ivan Mauricio Cabezas Troyano

Sustainability is a global concern. It must be addressed by different sectors of society, even by the information technology sector. Moreover, such effort should not be only focused on direct impacts of technology over the environment, but also on the software engineering discipline by itself, which is facing now other dimensions of sustainability. In this paper, an adaptation of the Attribute-Driven Design method including sustainability as a driver is introduced. The proposal is based on… Mostrar más

Sustainability is a global concern. It must be addressed by different sectors of society, even by the information technology sector. Moreover, such effort should not be only focused on direct impacts of technology over the environment, but also on the software engineering discipline by itself, which is facing now other dimensions of sustainability. In this paper, an adaptation of the Attribute-Driven Design method including sustainability as a driver is introduced. The proposal is based on sustainability guidelines established by the Karlskrona Manifesto. It involves a multidimensional sustainability analysis considering three levels of impacts and opportunities for each one of the architectural components. The adaptation is motivated by the design of a sustainable architecture of a cloud-based personal health record. The designed architecture is termed Health Catalogue Repository. It offers cloud services, allowing interoperability and timely access to patients’ clinical information. Energy consumption and resources optimization are contemplated like fundamental sustainability characteristics in the architectural design. The achieved design offers a better trade-off among quality attributes and sustainability constraints. The achieved design by using the proposal reduces the long-term impacts whilst increases the sustainability opportunities in architectural components. Mostrar menos

Clinical Decision Support Systems (CDSS) were explicitly introduced in the 90's with the aim of providing knowledge to clinicians in order to influence its decisions and, therefore, improve patients' health care. There are different architectural approaches for implementing CDSS. Some of these approaches are based on cloud computing, which provides on-demand computing resources over internet. The goal of this paper is to determine and discuss key issues and approaches involving architectural… Mostrar más

Clinical Decision Support Systems (CDSS) were explicitly introduced in the 90's with the aim of providing knowledge to clinicians in order to influence its decisions and, therefore, improve patients' health care. There are different architectural approaches for implementing CDSS. Some of these approaches are based on cloud computing, which provides on-demand computing resources over internet. The goal of this paper is to determine and discuss key issues and approaches involving architectural designs in implementing a CDSS using cloud computing. To this end, we performed a standard Systematic Literature Review (SLR) of primary studies showing the intervention of cloud computing on CDSS implementations. Twenty-one primary studies were reviewed. We found that CDSS architectural components are similar in most of studies. Cloud-based CDSS are most used in Home Healthcare and Emergency Medical Systems. Alerts/Reminders and Knowledge Service are the most common implementations. Major challenges are around security, performance and compatibility. We concluded on the benefits of implementing a cloud-based CDSS, since it allows cost-efficient, ubiquitous and elastic computing resources. We highlight that some studies show weaknesses regarding the conceptualization of a cloud-based computing approach and lack of a formal methodology in the architectural design process. Mostrar menos

The stereo correspondence problem has received significant attention in literature during approximately three decades. During that period of time, the development on stereo matching algorithms has been quite considerable. In contrast, the proposals on evaluation methods for stereo matching algorithms are not so many. This is not trivial issue, since an objective assessment of algorithms is required not only to measure improvements on the area, but also to properly identify where the gaps really… Mostrar más

The stereo correspondence problem has received significant attention in literature during approximately three decades. During that period of time, the development on stereo matching algorithms has been quite considerable. In contrast, the proposals on evaluation methods for stereo matching algorithms are not so many. This is not trivial issue, since an objective assessment of algorithms is required not only to measure improvements on the area, but also to properly identify where the gaps really are, and consequently, guiding the research. In this paper, a systematic review on evaluation methods for stereo matching algorithms is presented. The contributions are not only on the found results, but also on how it is explained and presented: aiming to be useful for the researching community on visual computing, in which such systematic review process is not yet broadly adopted. Mostrar menos

The camera calibration problem consists in estimating intrinsic and extrinsic parameters. It can be solved by computing a 3x3 matrix enclosing such parameters - the fundamental matrix -, which can be obtained from a set of corresponding points. Nevertheless, in practice, corresponding points may be falsely matched or badly located, due to occlusion and ambiguity. Moreover, if the set of corresponding points does not include information on existing scene depth, the estimated fundamental matrix… Mostrar más

The camera calibration problem consists in estimating intrinsic and extrinsic parameters. It can be solved by computing a 3x3 matrix enclosing such parameters - the fundamental matrix -, which can be obtained from a set of corresponding points. Nevertheless, in practice, corresponding points may be falsely matched or badly located, due to occlusion and ambiguity. Moreover, if the set of corresponding points does not include information on existing scene depth, the estimated fundamental matrix may not be able to correctly recover the epipolar geometry. In this paper, an EA-based method for accurately selecting estimated corresponding points is introduced. It considers geometric issues that were ignored in previous EA-based approaches. Two selection operators were evaluated and obtained similar results. Additionally, a mutation operator is designed to tackle bad located points by shifting disparity vectors. An inter-technique comparison is performed against a standard camera calibration method. The qualitative evaluation is conducted by analysing obtained epipolar lines, regarding expected appearance, based on a-priori knowledge of camera systems during the capturing process. The quantitative evaluation of the proposed method is based on residuals. Experimental results shown the proposed method is able to correctly reconstruct the epipolar geometry. Mostrar menos

The main contribution of this paper is the introduction of a continuous improvement cycle for devising teaching scenarios and conducting learning experiences in engineering. The proposed cycle consists of seven steps on which gamification theory and ABET criteria are combined. It arose from the adaptation of a gamification design framework, commonly used in industry, into the specific context of high quality education in engineering. It is formulated at high level. Consequently, it should be… Mostrar más

The main contribution of this paper is the introduction of a continuous improvement cycle for devising teaching scenarios and conducting learning experiences in engineering. The proposed cycle consists of seven steps on which gamification theory and ABET criteria are combined. It arose from the adaptation of a gamification design framework, commonly used in industry, into the specific context of high quality education in engineering. It is formulated at high level. Consequently, it should be useful for practitioners having different requirements and expectations. A developed practice, following the proposed cycle, is presented, discussed and evaluated. In particular, the proposal is applied and exemplified, in a scenario for teaching introductory concepts of computer programming in a first-year course. A digital game was used within a gamified learning experience, as a teaching tool. However, the learning process does not rely solely on the use of the game by itself. Moreover, the devised scenario has a purpose beyond edutainment: contributing to achievement of student outcomes, under a continuous improvement approach, according to ABET. A quantitative and qualitative evaluation of the developed practice was performed. A positive impact on students' emotional engagement and behavior was observed as a result of the evaluation process. Mostrar menos

Template matching has multiple applications on different problems in computer vision. Image distortions remain as the main challenge that template matching algorithms have to overcome. Thus, measuring robustness of algorithms against distortion conditions is an important task. Moreover, a comparison among template matching algorithms is difficult to achieve due to the lack of a standard evaluation methodology. In this paper, a measurement for quantifying the robustness of template matching… Mostrar más

Template matching has multiple applications on different problems in computer vision. Image distortions remain as the main challenge that template matching algorithms have to overcome. Thus, measuring robustness of algorithms against distortion conditions is an important task. Moreover, a comparison among template matching algorithms is difficult to achieve due to the lack of a standard evaluation methodology. In this paper, a measurement for quantifying the robustness of template matching algorithms against a single distortion is introduced. In addition, a procedure for comparing template matching algorithms is presented, aiming to become an evaluation standard. The comparison of template matching algorithms is formulated as a Multi-objective Optimisation problem. Experimental evaluation of the proposed procedure, using the robustness coefficient, is conducted by comparing algorithms based on full-search and different similarity measurements. Mostrar menos

Health professionals should record clinical care information in order to provide adequate patient assistance. Such recording process requires an Electronic Health Record (EHR) with complete and integral information adjusted to treatments performed on a patient. Moreover, availability and access to EHR are key features supporting decision making and improve patient care. Nevertheless, designing an EHR fulfilling a set of quality attributes is not an easy task. In fact, an EHR with low usability… Mostrar más

Health professionals should record clinical care information in order to provide adequate patient assistance. Such recording process requires an Electronic Health Record (EHR) with complete and integral information adjusted to treatments performed on a patient. Moreover, availability and access to EHR are key features supporting decision making and improve patient care. Nevertheless, designing an EHR fulfilling a set of quality attributes is not an easy task. In fact, an EHR with low usability causes deficient clinical services and poor data quality on medical records. In this paper, an interpretation of the ISO 9241-210 standard, in the context of patients' care in an emergency situation, is presented. It considers three mid-level objectives: understanding, designing and evaluating. In this way, an alignment between high-level guidelines, offered by usability standards, and low-level activities to be followed during an EHR design, is achieved. Mostrar menos

The use of disparity estimation algorithms is required in the 3D recovery process from stereo images. These algorithms tackle the correspondence problem by computing a disparity map. The accuracy assessment of a disparity estimation process has multiple applications such as comparing among different algorithms’ performance, tuning algorithm’s parameters within a particular context, and determining the impact of components, among others. Disparity estimation algorithms can be assessed by… Mostrar más

The use of disparity estimation algorithms is required in the 3D recovery process from stereo images. These algorithms tackle the correspondence problem by computing a disparity map. The accuracy assessment of a disparity estimation process has multiple applications such as comparing among different algorithms’ performance, tuning algorithm’s parameters within a particular context, and determining the impact of components, among others. Disparity estimation algorithms can be assessed by following an evaluation methodology. This chapter is dedicated to present and discuss methodologies for evaluating disparity estimation algorithms. The discussion begins with a review of the state-of-the-art. The constitutive components of a methodology are analysed. Finally, advantages and drawbacks of existing methodologies are presented. Mostrar menos

The percentage of Bad Matched Pixels (BMP) is widely used for evaluating disparity maps. It counts the number of differences between estimated disparity values and ground-truth values that exceed a threshold. A small error is counted in the same way that a large one by computing this measure. Moreover, the BMP ignores the inverse relation between depth and disparity. Although, the percentages of BMP are equal, those disparity maps may produce different 3D reconstructions. The Mean Relative… Mostrar más

The percentage of Bad Matched Pixels (BMP) is widely used for evaluating disparity maps. It counts the number of differences between estimated disparity values and ground-truth values that exceed a threshold. A small error is counted in the same way that a large one by computing this measure. Moreover, the BMP ignores the inverse relation between depth and disparity. Although, the percentages of BMP are equal, those disparity maps may produce different 3D reconstructions. The Mean Relative Error (MRE) is calculated as an average of ratios of error magnitudes against true disparity values. It considers the inverse relation between depth and disparity. However, using the MRE, every deviation from ground-truth is considered as an error, regardless the application domain for which the disparity map was estimated. In this paper, an error measure devised for evaluating disparity maps is introduced. The introduced measure combines the advantages of the BMP and the MRE. It allows a user to declare what an estimation error is – using a threshold – and considers both, the error magnitude and the inverse relation between depth and disparity. The proposed measures is termed BMPRE and it determines estimation errors in a widely adopted way by the community and, at the same time, offers not only information, but flexibility, about the impact of those errors in the context of a 3D recovery process. Comparative analysis and experimental evaluation show that the BMPRE allows a fair evaluation of disparity maps, which impacts on a quantitative comparison of stereo correspondence algorithms. Mostrar menos

Multi-objective problems are characterised by the presence of a set of optimal trade-off solutions –a Pareto front–, from which a solution has to be selected by a decision maker. However, selecting a solution from a Pareto front depends on large quantities of solutions to select from and dimensional complexity due to many involved objectives, among others. Commonly, the selection of a solution is based on preferences specified by a decision maker. Nevertheless a decision maker may have not… Mostrar más

Multi-objective problems are characterised by the presence of a set of optimal trade-off solutions –a Pareto front–, from which a solution has to be selected by a decision maker. However, selecting a solution from a Pareto front depends on large quantities of solutions to select from and dimensional complexity due to many involved objectives, among others. Commonly, the selection of a solution is based on preferences specified by a decision maker. Nevertheless a decision maker may have not preferences at all. Thus, an informed decision making process has to be done, which is difficult to achieve. In this paper, selecting a solution from a Pareto front is addressed as a multi-objective problem using two utility functions and operating in the objective space. A quantitative comparison of stereo correspondence algorithms performance is used as an application domain. Mostrar menos

A quantitative evaluation methodology for disparity maps includes the selection of an error measure. Among existing measures, the percentage of bad matched pixels is commonly used. Nevertheless, it requires an error threshold. Thus, a score of zero bad matched pixels does not necessarily imply that a disparity map is free of errors. On the other hand, we have not found publications on the evaluation process where different error measures are applied. In this paper, error measures are… Mostrar más

A quantitative evaluation methodology for disparity maps includes the selection of an error measure. Among existing measures, the percentage of bad matched pixels is commonly used. Nevertheless, it requires an error threshold. Thus, a score of zero bad matched pixels does not necessarily imply that a disparity map is free of errors. On the other hand, we have not found publications on the evaluation process where different error measures are applied. In this paper, error measures are characterised in order to provide the bases to select a measure during the evaluation process. An analysis of the impact on results of selecting different error measures on the evaluation of disparity maps is conducted based on the presented characterisation. The evaluation results showed that there is a lack of consistency on the results achieved by considering different error measures. It has an impact on interpreting the accuracy of stereo correspondence algorithms Mostrar menos

A comparison of stereo correspondence algorithms can be conducted by a quantitative evaluation of disparity maps. Among the existing evaluation methodologies, the Middlebury’s methodology is commonly used. However, the Middlebury’s methodology has shortcomings in the evaluation model and the error measure. These shortcomings may bias the evaluation results, and make a fair judgment about algorithms accuracy difficult. An alternative, the A* methodology is based on a multiobjective optimisation… Mostrar más

A comparison of stereo correspondence algorithms can be conducted by a quantitative evaluation of disparity maps. Among the existing evaluation methodologies, the Middlebury’s methodology is commonly used. However, the Middlebury’s methodology has shortcomings in the evaluation model and the error measure. These shortcomings may bias the evaluation results, and make a fair judgment about algorithms accuracy difficult. An alternative, the A* methodology is based on a multiobjective optimisation model that only provides a subset of algorithms with comparable accuracy. In this paper, a quantitative evaluation of disparity maps is proposed. It performs an exhaustive assessment of the entire set of algorithms. As innovative aspect, evaluation results are shown and analysed as disjoint groups of stereo correspondence algorithms with comparable accuracy. This innovation is obtained by a partitioning and grouping algorithm. On the other hand, the used error measure offers advantages over the error measure used in the Middlebury’s methodology. The experimental validation is based on the Middlebury’s test-bed and algorithms repository. The obtained results show seven groups with different accuracies. Moreover, the top-ranked stereo correspondence algorithms by the Middlebury’s methodology are not necessarily the most accurate in the proposed methodology. Mostrar menos

The quantitative evaluation of disparity maps is based on error measures. Among the existing measures, the percentage of Bad Matched Pixels (BMP) is widely adopted. Nevertheless, the BMP does not consider the magnitude of the errors and the inherent error of stereo systems, in regard to the inverse relation between depth and disparity. Consequently, different disparity maps, with quite similar percentages of BMP, may produce 3D reconstructions of largely different qualities. In this paper, a… Mostrar más

The quantitative evaluation of disparity maps is based on error measures. Among the existing measures, the percentage of Bad Matched Pixels (BMP) is widely adopted. Nevertheless, the BMP does not consider the magnitude of the errors and the inherent error of stereo systems, in regard to the inverse relation between depth and disparity. Consequently, different disparity maps, with quite similar percentages of BMP, may produce 3D reconstructions of largely different qualities. In this paper, a ground-truth based measure of errors in estimated disparity maps is presented. It offers advantages over the BMP, since it takes into account the magnitude of the errors and the inverse relation between depth and disparity. Experimental validations of the proposed measure are conducted by using two state-of-the-art quantitative evaluation methodologies. Obtained results show that the proposed measure is more suited than BMP to evaluate the depth accuracy of the estimated disparity map. Mostrar menos

Performance evaluation of vision algorithms is a necessary step during a research process. It may supports inter and intra technique comparisons. A fair evaluation process requires of a methodology. Disparity estimation evaluation involves multiple aspects. However, conventional approaches rely on the use of a single value as an indicator of comparative performance. In this paper a non-linear quantitative evaluation approach for disparity estimation is introduced. It is supported by Pareto… Mostrar más

Performance evaluation of vision algorithms is a necessary step during a research process. It may supports inter and intra technique comparisons. A fair evaluation process requires of a methodology. Disparity estimation evaluation involves multiple aspects. However, conventional approaches rely on the use of a single value as an indicator of comparative performance. In this paper a non-linear quantitative evaluation approach for disparity estimation is introduced. It is supported by Pareto dominance and Pareto optimal set concepts. The proposed approach allows different evaluation scenarios, and offers advantages over traditional evaluation approaches. The experimental validation is conducted using ground truth data. Innovative results obtained by applying the proposed approach are presented and discussed. Mostrar menos