Extending the Battery Life of the ZigBee Routers and Coordinator by Modifying Their Mode of Operation.

Wireless sensor networks proliferate more and more in all social scopes and sectors. Such networks are implemented in smart homes, smart cities, security systems, medical resources, agriculture, automotive industry, etc. Communication devices and sensors of such networks are powered with batteries: the enlarging of battery life is a hot research topic. We focus on wireless sensor networks based on ZigBee technology. While sleep standard operation mode is defined for end devices, it is not the case for the rest of devices (routers and Coordinator), which usually always remain in active mode. We designed a formal optimization model for maximizing the enlarging of the battery life of routers and Coordinator, allowing us to delimit practical successful conditions. It was successfully tested with a standard ZigBee datasheet comprising technical data for sensors, routers, and coordinators. It was tested in a practical wireless sensor network assembly with XBee S2C devices. We derived, from the previous model, a novel but simple protocol of communication among routers and coordinators. It was tested in different use cases. We showed that when end devices generate traffic at regular intervals, the enlarging of the battery life of routers and Coordinator was possible only under certain use cases.

Hardware Mechanism for Energy Saving in WiFi Access Points.

Wireless fidelity (WiFi) networks are deployed in several varied environments all around the World. Usually, the wireless fidelity access points are always on in houses and other small companies. In buildings of large companies and public organizations and in university campuses the number of access points is elevated; they are powered using power over the ethernet and are always on. Consequently, they consume a considerable amount of electric energy. The last versions of the International Electric and Electronic Engineers 802.11 standardized procedures to save energy in a wireless fidelity terminal but not in the access point. We designed a formal method to show when energy can be saved in wireless fidelity access points considering different power supplies for the access point: an electric energy battery and a standard voltage supply. We use an external battery that stores electric energy during an interval of time from a standard voltage supply (Charge period). After that interval (Discharge period), the energy supply for the access point is the external battery. Those intervals of time are repeated sequentially (Charge and Discharge cycles). We verified our formal model implementing a hardware circuit that controls the power supply for the access point. The amount of energy saving for a large number of of access points during a long period of time is considerably high.

Low Cost Efficient Deliverying Video Surveillance Service to Moving Guard for Smart Home.

Low-cost video surveillance systems are attractive for Smart Home applications (especially in emerging economies). Those systems use the flexibility of the Internet of Things to operate the video camera only when an intrusion is detected. We are the only ones that focus on the design of protocols based on intelligent agents to communicate the video of an intrusion in real time to the guards by wireless or mobile networks. The goal is to communicate, in real time, the video to the guards who can be moving towards the smart home. However, this communication suffers from sporadic disruptions that difficults the control and drastically reduces user satisfaction and operativity of the system. In a novel way, we have designed a generic software architecture based on design patterns that can be adapted to any hardware in a simple way. The implanted hardware is of very low economic cost; the software frameworks are free. In the experimental tests we have shown that it is possible to communicate to the moving guard, intrusion notifications (by e-mail and by instant messaging), and the first video frames in less than 20 s. In addition, we automatically recovered the frames of video lost in the disruptions in a transparent way to the user, we supported vertical handover processes and we could save energy of the smartphone's battery. However, the most important thing was that the high satisfaction of the people who have used the system.

Interference Effects Redress over Power-Efficient Wireless-Friendly Mesh Networks for Ubiquitous Sensor Communications across Smart Cities.

Ubiquitous sensing allows smart cities to take control of many parameters (e.g., road traffic, air or noise pollution levels, etc.). An inexpensive Wireless Mesh Network can be used as an efficient way to transport sensed data. When that mesh is autonomously powered (e.g., solar powered), it constitutes an ideal portable network system which can be deployed when needed. Nevertheless, its power consumption must be restrained to extend its operational cycle and for preserving the environment. To this end, our strategy fosters wireless interface deactivation among nodes which do not participate in any route. As we show, this contributes to a significant power saving for the mesh. Furthermore, our strategy is wireless-friendly, meaning that it gives priority to deactivation of nodes receiving (and also causing) interferences from (to) the rest of the smart city. We also show that a routing protocol can adapt to this strategy in which certain nodes deactivate their own wireless interfaces.

Mobile sensing systems.

Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high.

Ubiquitous monitoring of electrical household appliances.

The number of appliances at home is increasing continuously, mainly because they make our lives easier. Currently, technology is integrated in all objects of our daily life. TCP/IP let us monitor our home in real time and check ubiquitously if something is happening at home. Bearing in mind this idea, we have developed a low-cost system, which can be used in any type of electrical household appliance that takes information from the appliance and posts the information to the Twitter Social network. Several sensors placed in the household appliances gather the sensed data and send them wired or wirelessly, depending on the case, using small and cheap devices to a gateway located in the home. This gateway takes decisions, based on the received data, and sends notifications to Twitter. We have developed a software application that takes the values and decides when to issue an alarm to the registered users (Twitter friends of our smart home). The performance of our system has been measured taking into account the home network (using IEEE 802.3u and IEEE 802.11g) and the data publishing in Twitter. As a result, we have generated an original product and service for any electrical household appliance, regardless of the model and manufacturer, that helps home users improve their quality of life. The paper also shows that there is no system with the same innovative features like the ones presented in this paper.

Architecture and protocol of a semantic system designed for video tagging with sensor data in mobile devices.

Current mobile phones come with several sensors and powerful video cameras. These video cameras can be used to capture good quality scenes, which can be complemented with the information gathered by the sensors also embedded in the phones. For example, the surroundings of a beach recorded by the camera of the mobile phone, jointly with the temperature of the site can let users know via the Internet if the weather is nice enough to swim. In this paper, we present a system that tags the video frames of the video recorded from mobile phones with the data collected by the embedded sensors. The tagged video is uploaded to a video server, which is placed on the Internet and is accessible by any user. The proposed system uses a semantic approach with the stored information in order to make easy and efficient video searches. Our experimental results show that it is possible to tag video frames in real time and send the tagged video to the server with very low packet delay variations. As far as we know there is not any other application developed as the one presented in this paper.

A hierarchical communication architecture for oceanic surveillance applications.

The interest in monitoring applications using underwater sensor networks has been growing in recent years. The severe communication restrictions imposed by underwater channels make that efficient monitoring be a challenging task. Though a lot of research has been conducted on underwater sensor networks, there are only few concrete applications to a real-world case study. In this work, hence, we propose a general three tier architecture leveraging low cost wireless technologies for acoustic communications between underwater sensors and standard technologies, Zigbee and Wireless Fidelity (WiFi), for water surface communications. We have selected a suitable Medium Access Control (MAC) layer, after making a comparison with some common MAC protocols. Thus the performance of the overall system in terms of Signals Discarding Rate (SDR), signalling delay at the surface gateway as well as the percentage of true detection have been evaluated by simulation, pointing out good results which give evidence in applicability's favour.

Asociación entre depresión e ideación suicida en un grupo de adolescentes colombianos / Association between Depression and Suicidal Ideation in a Group of Colombian Adolescents / Associação entre depressão e ideação suicida num grupo de adolescentes colombianos

Objetivo. Estimar la asociación entre los síntomas depresivos y la ideación suicida en adolescentes. Método. Se realizó un estudio de corte transeccional, en el cual se aplicó el Cuestionario de Depresión Infantil (CDI) y el Inventario de Ideación Suicida Positiva y Negativa (PANSI) a un grupo de 289 adolescentes escolarizados (126 hombres y 163 mujeres), con edades comprendidas entre 14 y 17 años, matriculados en cuatro instituciones educativas públicas de Tunja, Colombia. Resultados. El 30% de los participantes presentaron un nivel alto de ideación suicida y el 9% reportaron síntomas depresivos, hallándose puntuaciones más altas en mujeres que en hombres para ambas variables de estudio. También se encontraron relaciones significativas entre ideación suicida y ánimo negativo (rs= 0.43, p < 0.000), anhedonia (rs = 0.40, p < 0.000) y autoestima negativa (rs = 0.44, p < 0.000). Los análisis de regresión logística mostraron como factores predictores de ideación suicida en mujeres, el ánimo negativo y la autoestima negativa, mientras en los hombres no se identificó ningún factor predictor. Conclusión. Los síntomas depresivos relacionados con estado de ánimo y autoestima negativa son factores de riesgo relevantes asociados con el componente cognitivo de la conducta suicida en mujeres adolescentes.

Objective. To estimate the association between depression and suicidal ideation in adolescents. Method. The research was performed through a cross-sectional study, in which the Children's Depression Inventory (CDI) and the Positive and Negative Suicide Ideation Inventory (PANSI) was applied in a group of 289 school adolescents (126 men and 163 women), between 14 and 17 years old and enrolled in four public educational institutions of Tunja, Colombia. Results. 30% of participants were identified as presenting a high level of suicidal ideation and 9% reported depressive symptoms. Higher scores were found in females than males for both study variables. Likewise, through the Spearman correlation coefficient, significant correlations were found between suicidal ideation and negative mood (= 0.43, p < 0.000), anhedonia (= 0.40, p < 0.000) and negative self-esteem (= 0.44, p < 0.000); on the other hand, using logistic regression, the negative mood and negative self-esteem were found as predictors of suicidal ideation in women, while in men no predictive factor was identified. Conclusion. It is possible to establish that depressive symptoms associated with negative mood and self-esteem are significant risk factors associated with the cognitive component of suicidal behavior in adolescent women.

Escopo. Estimar a associação entre os sintomas depressivos e a ideação suicida em adolescentes. Metodologia. Foi feito um estudo de corte transeccional, no qual foi aplicado o Questionário de Depressão Infantil (CDI) e o Inventário de Ideação Suicida Positiva e Negativa (PANSI) num grupo de 289 adolescentes escolarizados (126 homens e 163 mulheres), com idades compreendidas entre 14 e 17 anos de idade, inscritos em quatro instituições educativas públicas de Tunja- Colômbia. Resultados. O 30% dos participantes presentaram um alto nível de ideação suicida e o 9% reportaram sintomas depressivos, sendo as pontuações mais altas as das mulheres em contraste com as dos homens para as duas variáveis do estudo. Também foram encontradas relações significativas entre ideação suicida e ânimo negativo (= 0.43, p < 0.000), anhedonia (= 0.40, p < 0.000) e autoestima negativa (= 0.44, p < 0.000). As análises de regressão logística mostraram como fatores preditores de ideação suicida em mulheres, o ânimo negativo e a autoestima negativa, enquanto que nos homens não foi identificado fator preditivo nenhum. Conclusão. Os sintomas depressivos relacionados com estado de ânimo e autoestima negativa são fatores de risco relevantes associados com o componente cognitivo da conduta suicida em mulheres adolescentes.

Factores asociados a ideación suicida en universitarios / Factors Associated with Suicidal Ideation in College Students

Estudio no experimental de tipo transeccional descriptivo cuyo objetivo fue identificar los factores asociados a ideación suicida en una muestra de 258 universitarios con edades comprendidas entre los 18 y los 24 años, pertenecientes a una universidad ubicada en el departamento de Boyacá; a partir del inventario de ideación suicida positiva y negativa (PANSI), la Escala de autoevaluación para la depresión de Zung (SDS), la Escala de impulsividad de Barratt (BIS), el Cuestionario de dependencia emocional (CDE), la Escala de eventos vitales estresantes (EEVA) y una ficha sociodemográfica. El análisis de resultados indican que el 31 % de la población participante presentó ideación suicida, hallándose a partir de las pruebas U de Mann-Whitney y Kruskal Wallis, que el estado civil unión libre, los eventos vitales estresantes, la dependencia emocional, la impulsividad y la depresión son factores asociados a ideación en universitarios.

Transactional descriptive non-experimental study aimed to identify factors associated with suicidal ideation in a sample of 258 college students aged between 18 and 24 years old, belonging to a university located in the Boyacá state; through the Positive and Negative Suicide Ideation Inventory (PANSI), the Zung Self-Rating Depression Scale (SDS), the Barratt Impulsiveness Scale (BIS), Emotional Dependency Questionnaire (CDE), Stressful Life Events Scale (EEVA) and a socio-demographic questionnaire. The analysis results indicate 31 % of the participant population had suicidal ideation, being from the U Mann-Whitney and Kruskal Wallis, the common law marital status, stressful life events, emotional dependency, impulsivity and depression are factors associated with suicidal ideation in college.

Relación entre ansiedad y estilos de personalidad en estudiantes de Psicología / Relationship between anxiety and personality styles in Psychology students

Resumen El presente estudio no experimental de tipo correlacional se realizó con el objetivo de establecer y analizar la relación entre ansiedad y estilos de personalidad en estudiantes de Psicología de una universidad colombiana, mediante la aplicación del Inventario de Ansiedad Rasgo-Estado (IDARE) y el Inventario Millon de Estilos de Personalidad (MIPS) en su adaptación española, a 121 estudiantes (34 hombres y 87 mujeres), con edades comprendidas entre 18 y 33 años, seleccionados mediante un muestreo estratificado simple. El análisis de datos, se realizó mediante el coeficiente de correlación de Pearson. En el estudio se encontró que existe relación entre ansiedad estado y los estilos de personalidad expansión, retraimiento y descontento; mientras ansiedad rasgo correlaciona con los estilos expansión, decisión, preservación, introversión, indecisión, sumisión y descontento.

Abstract This study not experimental and correlational aimed to establish and analyze the relationship between anxiety and personality styles in Psychology students of Colombian's university, through the application the Trait Anxiety Inventory-State (IDARE) and the Millon Index of Personality Styles (MIPS) in its Spanish adaptation. The sample consisted of 121 students (34 men and 87 women) aged between 18 and 33 years old, they were selected through a stratified simple sampling. Data analysis was performed using the Pearson correlation coefficient. The study found relationship between state anxiety and personality styles Enhancing, Internally Focused, Intuiting and Dissenting, while trait anxiety correlated with styles Enhancing, Asserting, Pleasure, Internally Focused, Hesitating, Yielding and Complaining.