Gabriela Marín

Performance Analysis of Sensor Placement Strategies on a Wireless Sensor Network

The positioning of nodes in a sensor network has an effect in its performance. In this paper, two predefined configurations are compared to the random distribution to gauge the magnitude of the effect on energy consumption of each type of sensor allocation. The experiments assume a flat, obstacle free, rectangular field, with Directed Diffusion used as routing protocol, and random different positions for the querying entity (sink) and the event location in the field. The results confirm that in an environment such as this, it is worth investing in the uniform positioning of sensors as they offer a significant performance gain.

Time delay performance analysis of sensor allocation strategies on a WSN

In many of query-based WSN applications, response time factor is an essential issue. Overall performance under different sensor placements depends on the pattern of queries requested from the network, which in turn might depend on the physical segmentation of the field. This paper explores three predefined configurations in order to compare the time delay performance. The experiments showed that the Uniform distribution of the nodes was the strategy that obtains the fastest response time, and as expected, Random is the one with the slowest.

Human aspects of ubiquitous computing: a study addressing willingness to use it and privacy issues

Identifying the human aspects related to ubiquitous systems focused on people’s willingness to use them and privacy concerns was our goal. We selected two ubiquitous systems: a wearable system (Google Glass) and an embedded in context system (Smart Environments). An online survey, with more than 400 participants, which included questions about how people perceive privacy issues related to the use of these two different ubiquitous systems, was conducted. Results show that privacy is not the only factor defining predisposition or aversion towards using ubiquitous systems. Financial, risk, and convenience factors are the others. We discovered that the importance of these factors on the decision to use them or not depends on the system. Regarding privacy, Google Glass generates a higher degree of concern than the Smart Environments alternative. Female participants tend to be more worried than male participants, independently of the ubiquitous system considered. Finally, the youngest participants (16–25 years old) are the most concerned about privacy threats, which was unexpected.

Towards Smart Notifications - An Adaptive Approach Using Smart Devices

The use of smart devices is increasing rapidly; this trend is changing the paradigm in which notifications are delivered to users. Smart devices are important to provide user awareness. However, their use must be controlled and human perception should be considered to avoid information overload. In this paper, we present a dynamic mechanism to coordinate the distribution of notification across smart devices. This personalized notification mechanism uses an inference engine and a set of rules to generate notification alternatives and select the “best” one. A continuous refinement approach is also used to improve notification delivery. Our system was evaluated and the baseline rules were established by 11 expert users. The main results show that in some scenarios, the notification mechanism selection converged quickly and results are promising. However, further work is required to provide not only personalized but integrated (i.e., more than one device at the time) notification management.

Use of Emerging 3D Printing and Modeling Technologies in the Health Domain

Three-Dimensional (3D) technologies emerged from the technological advances in manufacturing required to produce physical versions of digital models. The most attractive feature of 3D technologies is that virtual models are easy to mold, and custom-made items can be physically produced. Health domains are areas in which 3D technologies have been applied, and several studies have been conducted assessing the usefulness of such technologies in those domains. In this paper we present the results of a Systematic Literature Review (SLR) on the applications of 3D technologies in the health domain. Discussion from the revision of 33 papers is presented. The main finding of this SLR is that none of the available research papers are focused on computer science related areas (i.e., all papers are published by doctors or researchers in Medicine). Moreover, all the included papers were published in journals specialized in Medicine. Therefore, they do not delve in the computational conclusions of the studies. In this article, we identified significant research gaps (from the computational perspective), as well as new ideas are being proposed on the future of 3D technologies in health.

GQM + Strategies and IDEAL: A Combination of Approaches to Achieve Continuous SPI

GQM+Strategies is an approach that aligns the business goals at each level of an organization to strategies and assesses the achievement of goals. The IDEAL model is an organizational improvement model. In this paper, we present our experiences applying the IDEAL model and GQM+Strategies to conduct continuous software process improvement (SPI) and establish a measurement program in a large multi-industry state-owned company. Our goal is to provide evidence of the use of these methods and models in such complex scenarios. The motivation for this paper was the lack of “from the trenches” perspectives on SPI in this kind of contexts. The main challenges faced during the experiences reported in this paper include: rigid control structures used to manage and monitor IT investment, inadequate or incomplete use of other measurement methods, and lack of continuous improvement culture (due to many years in a monopolistic industry). Moreover, we present ways in which we combined GQM+Strategies and the IDEAL model to deploy a continuous process improvement program in a context of limited resources and serious business threats, and to convince the company employees of the need for process improvement.

Understanding Notional Machines through Traditional Teaching with Conceptual Contraposition and Program Memory Tracing

A correct understanding about how computers run code is mandatory in order to effectively learn to program. Lectures have historically been used in programming courses to teach how computers execute code, and students are assessed through traditional evaluation methods, such as exams. Constructivism learning theory objects to students’ passiveness during lessons, and traditional quantitative methods for evaluating a complex cognitive process such as understanding. Constructivism proposes complimentary techniques, such as conceptual contraposition and colloquies. We enriched lectures of a “Programming II” (CS2) course combining conceptual contraposition with program memory tracing, then we evaluated students’ understanding of programming concepts through colloquies. Results revealed that these techniques applied to the lecture are insufficient to help students develop satisfactory mental models of the C++ notional machine, and colloquies behaved as the most comprehensive traditional evaluations conducted in the course.

Tablet Use Patterns and Drivers of User Satisfaction: A Gender Approach

Understanding what for, when and where Computer Science students at the University of Costa Rica use tablets and identifying gender differences in their use were our goals. An online survey, which included closed and open questions, was conducted. Results show that women use their tablet more for leisure and appreciate it for its usability. Non-working men use tablets also for leisure but value their functionality. Finally, working men are more interested in tablets as support to their work, and value usability more than non-working men.

Smart Cities in Latin America

In almost every forum around the world, country leaders are discussing the necessity of creating smart cities. However, even the term “smart city” is diffuse nowadays. Some countries want their cities to become smarter and others want to create smart cities from scratch. Several mappings have been developed around the world to locate the smartest cities. We believe that, since Latin American and Caribbean countries are exploring in the creation of smart cities, a proper mapping and plan is necessary to assure that the efforts in creating smart cities are not a waste. Using a literature review and a survey, we try to determine the state of smart cities development and its technical readiness in the Region.

Sign Language Recognition Model Combining Non-manual Markers and Handshapes

People with disabilities have fewer opportunities. Technological developments should be used to help these people to have more opportunities. In this paper we present partial results of a research project which aims to help people with disabilities, specifically deaf and hard of hearing. We present a sign language recognition model. The model takes advantage of the natural user interfaces (NUI) and a classification algorithm (support vector machines). Moreover, we combine handshapes (signs) and non-manual markers (associated to emotions and face gestures) in the recognition process to enhance the sign language expressivity recognition. Additionally, non-manual markers representation is proposed. A model evaluation is also reported.