Design and Performance Evaluation of Network-on-Chip Communication Protocols and Architectures

The scale down of transistor technology allows microelectronics manufacturers such as Intel and IBM to build always more sophisticated systems on a single microchip. The classical interconnection solutions based on shared buses or direct connections between the modules of the chip are becoming obsolete as they struggle to sustain the increasing tight bandwidth and latency constraints that these systems demand. The most promising solution for the future chip interconnects are the Networks on Chip (NoC). NoCs are network composed by routers and channels used to inter- connect the different components installed on the single microchip. Examples of advanced processors based on NoC interconnects are the IBM Cell processor, composed by eight CPUs that is installed on the Sony Playstation III and the Intel Teraflops pro ject composed by 80 independent (simple) microprocessors. On chip integration is becoming popular not only in the Chip Multi Processor (CMP) research area but also in the wider and more heterogeneous world of Systems on Chip (SoC). SoC comprehend all the electronic devices that surround us such as cell-phones, smart-phones, house embedded systems, automotive systems, set-top boxes etc... SoC manufacturers such as ST Microelectronics , Samsung, Philips and also Universities such as Bologna University, M.I.T., Berkeley and more are all proposing proprietary frameworks based on NoC interconnects. These frameworks help engineers in the switch of design methodology and speed up the development of new NoC-based systems on chip. In this Thesis we propose an introduction of CMP and SoC interconnection networks. Then focusing on SoC systems we propose: • a detailed analysis based on simulation of the Spidergon NoC, a ST Microelectronics solution for SoC interconnects. The Spidergon NoC differs from many classical solutions inherited from the parallel computing world. Here we propose a detailed analysis of this NoC topology and routing algorithms. Furthermore we propose aEqualized a new routing algorithm designed to optimize the use of the resources of the network while also increasing its performance; • a methodology flow based on modified publicly available tools that combined can be used to design, model and analyze any kind of System on Chip; • a detailed analysis of a ST Microelectronics-proprietary transport-level protocol that the author of this Thesis helped developing; • a simulation-based comprehensive comparison of different network interface designs proposed by the author and the researchers at AST lab, in order to integrate shared-memory and message-passing based components on a single System on Chip; • a powerful and flexible solution to address the time closure exception issue in the design of synchronous Networks on Chip. Our solution is based on relay stations repeaters and allows to reduce the power and area demands of NoC interconnects while also reducing its buffer needs; • a solution to simplify the design of the NoC by also increasing their performance and reducing their power and area consumption. We propose to replace complex and slow virtual channel-based routers with multiple and flexible small Multi Plane ones. This solution allows us to reduce the area and power dissipation of any NoC while also increasing its performance especially when the resources are reduced. This Thesis has been written in collaboration with the Advanced System Technology laboratory in Grenoble France, and the Computer Science Department at Columbia University in the city of New York.

Learn-Achieve-Succeed: New technologies for enhancing student performance

Tegrity Campus 2.0 is the first student achievement system that impacts learning across the entire institution, improving retention and student satisfaction. Tegrity makes class time available all the time by automatically capturing, storing and indexing every class on campus for replay by every student. With Tegrity, students quickly recall key moments or replay entire classes online, with digital notes, on their iPods and cell phones. [See PDF for complete abstract]

The Choosing Healthy Options of Starches (CHOOS) diet and dietary intake self-monitoring for weight loss among adolescent females

Previous research has shown dietary intake self-monitoring, and culturally tailored weight loss interventions to be effective tools for weight loss. Technology can be used to tailor weight loss interventions to better suit adolescents. There is a lack of research to date on the use of personal digital assistants (PDAs) to self-monitor dietary intake among adolescents. The objective of this study was to determine the difference in dietary intake self-monitoring frequency between using a Personal Digital Assistant (PDA) or paper logs as a diet diary in obese adolescent females; and to describe differences in diet adherence, as well as changes in body size and self-efficacy to resist eating. We hypothesized dietary intake self-monitoring frequency would be greater during PDA use than during paper log use. This study was a randomized crossover trial. Participants recorded their diet for 4 weeks: 2 weeks on a PDA and 2 weeks on paper logs. Thirty-four obese females ages 12-20 were recruited for participation. Thirty were included in analyses. Participants recorded more entries/day while using the paper logs (4.10 entries/day ± 0.63) than while using the PDA (3.01 entries/day ±0.75) (p<0.001). Significantly more meals and snacks were skipped during paper log use (0.81/day ± 0.65) than during PDA use (0.23/day ± 0.22) (p=0.011). Changes in body size (BMI, weight, and waist circumference) and self-efficacy to resist eating did not differ significantly between PDA and paper log use. When compared to paper logs, participants felt the PDA was more convenient (p=0.020), looked forward to using the PDA more (p=0.008), and would rather continue using the PDA than the paper logs (p=0.020). The findings of this study indicate use of a PDA as a dietary intake self-monitoring tool among adolescents would not result in increased dietary intake self-monitoring to aid in weight loss. Use of paper logs would result in greater data returned to clinicians, though use of PDAs would likely get adolescents more excited about adhering to recommendations to record their diet. Future research should look at updated communication devices, such as cell phones and other PDAs with additional features, and the role they can play in increasing dietary intake self-monitoring among adolescents.^

Integrated luminescent chemical microsensors based on GaN LEDs for security applications using smartphones

Development of PCB-integrateable microsensors for monitoring chemical species is a goal in areas such as lab-on-a-chip analytical devices, diagnostics medicine and electronics for hand-held instruments where the device size is a major issue. Cellular phones have pervaded the world inhabitants and their usefulness has dramatically increased with the introduction of smartphones due to a combination of amazing processing power in a confined space, geolocalization and manifold telecommunication features. Therefore, a number of physical and chemical sensors that add value to the terminal for health monitoring, personal safety (at home, at work) and, eventually, national security have started to be developed, capitalizing also on the huge number of circulating cell phones. The chemical sensor-enabled “super” smartphone provides a unique (bio)sensing platform for monitoring airborne or waterborne hazardous chemicals or microorganisms for both single user and crowdsourcing security applications. Some of the latest ones are illustrated by a few examples. Moreover, we have recently achieved for the first time (covalent) functionalization of p- and n-GaN semiconductor surfaces with tuneable luminescent indicator dyes of the Ru-polypyridyl family, as a key step in the development of innovative microsensors for smartphone applications. Chemical “sensoring” of GaN-based blue LED chips with those indicators has also been achieved by plasma treatment of their surface, and the micrometer-sized devices have been tested to monitor O2 in the gas phase to show their full functionality. Novel strategies to enhance the sensor sensitivity such as changing the length and nature of the siloxane buffer layer are discussed in this paper.

Design and control of multi-finger haptic devices for dexterous manipulation

En la interacción con el entorno que nos rodea durante nuestra vida diaria (utilizar un cepillo de dientes, abrir puertas, utilizar el teléfono móvil, etc.) y en situaciones profesionales (intervenciones médicas, procesos de producción, etc.), típicamente realizamos manipulaciones avanzadas que incluyen la utilización de los dedos de ambas manos. De esta forma el desarrollo de métodos de interacción háptica multi-dedo dan lugar a interfaces hombre-máquina más naturales y realistas. No obstante, la mayoría de interfaces hápticas disponibles en el mercado están basadas en interacciones con un solo punto de contacto; esto puede ser suficiente para la exploración o palpación del entorno pero no permite la realización de tareas más avanzadas como agarres. En esta tesis, se investiga el diseño mecánico, control y aplicaciones de dispositivos hápticos modulares con capacidad de reflexión de fuerzas en los dedos índice, corazón y pulgar del usuario. El diseño mecánico de la interfaz diseñada, ha sido optimizado con funciones multi-objetivo para conseguir una baja inercia, un amplio espacio de trabajo, alta manipulabilidad y reflexión de fuerzas superiores a 3 N en el espacio de trabajo. El ancho de banda y la rigidez del dispositivo se han evaluado mediante simulación y experimentación real. Una de las áreas más importantes en el diseño de estos dispositivos es el efector final, ya que es la parte que está en contacto con el usuario. Durante este trabajo se ha diseñado un dedal de bajo peso, adaptable a diferentes usuarios que, mediante la incorporación de sensores de contacto, permite estimar fuerzas normales y tangenciales durante la interacción con entornos reales y virtuales. Para el diseño de la arquitectura de control, se estudiaron los principales requisitos para estos dispositivos. Entre estos, cabe destacar la adquisición, procesado e intercambio a través de internet de numerosas señales de control e instrumentación; la computación de equaciones matemáticas incluyendo la cinemática directa e inversa, jacobiana, algoritmos de detección de agarres, etc. Todos estos componentes deben calcularse en tiempo real garantizando una frecuencia mínima de 1 KHz. Además, se describen sistemas para manipulación de precisión virtual y remota; así como el diseño de un método denominado "desacoplo cinemático iterativo" para computar la cinemática inversa de robots y la comparación con otros métodos actuales. Para entender la importancia de la interacción multimodal, se ha llevado a cabo un estudio para comprobar qué estímulos sensoriales se correlacionan con tiempos de respuesta más rápidos y de mayor precisión. Estos experimentos se desarrollaron en colaboración con neurocientíficos del instituto Technion Israel Institute of Technology. Comparando los tiempos de respuesta en la interacción unimodal (auditiva, visual y háptica) con combinaciones bimodales y trimodales de los mismos, se demuestra que el movimiento sincronizado de los dedos para generar respuestas de agarre se basa principalmente en la percepción háptica. La ventaja en el tiempo de procesamiento de los estímulos hápticos, sugiere que los entornos virtuales que incluyen esta componente sensorial generan mejores contingencias motoras y mejoran la credibilidad de los eventos. Se concluye que, los sistemas que incluyen percepción háptica dotan a los usuarios de más tiempo en las etapas cognitivas para rellenar información de forma creativa y formar una experiencia más rica. Una aplicación interesante de los dispositivos hápticos es el diseño de nuevos simuladores que permitan entrenar habilidades manuales en el sector médico. En colaboración con fisioterapeutas de Griffith University en Australia, se desarrolló un simulador que permite realizar ejercicios de rehabilitación de la mano. Las propiedades de rigidez no lineales de la articulación metacarpofalange del dedo índice se estimaron mediante la utilización del efector final diseñado. Estos parámetros, se han implementado en un escenario que simula el comportamiento de la mano humana y que permite la interacción háptica a través de esta interfaz. Las aplicaciones potenciales de este simulador están relacionadas con entrenamiento y educación de estudiantes de fisioterapia. En esta tesis, se han desarrollado nuevos métodos que permiten el control simultáneo de robots y manos robóticas en la interacción con entornos reales. El espacio de trabajo alcanzable por el dispositivo háptico, se extiende mediante el cambio de modo de control automático entre posición y velocidad. Además, estos métodos permiten reconocer el gesto del usuario durante las primeras etapas de aproximación al objeto para su agarre. Mediante experimentos de manipulación avanzada de objetos con un manipulador y diferentes manos robóticas, se muestra que el tiempo en realizar una tarea se reduce y que el sistema permite la realización de la tarea con precisión. Este trabajo, es el resultado de una colaboración con investigadores de Harvard BioRobotics Laboratory. ABSTRACT When we interact with the environment in our daily life (using a toothbrush, opening doors, using cell-phones, etc.), or in professional situations (medical interventions, manufacturing processes, etc.) we typically perform dexterous manipulations that involve multiple fingers and palm for both hands. Therefore, multi-Finger haptic methods can provide a realistic and natural human-machine interface to enhance immersion when interacting with simulated or remote environments. Most commercial devices allow haptic interaction with only one contact point, which may be sufficient for some exploration or palpation tasks but are not enough to perform advanced object manipulations such as grasping. In this thesis, I investigate the mechanical design, control and applications of a modular haptic device that can provide force feedback to the index, thumb and middle fingers of the user. The designed mechanical device is optimized with a multi-objective design function to achieve a low inertia, a large workspace, manipulability, and force-feedback of up to 3 N within the workspace; the bandwidth and rigidity for the device is assessed through simulation and real experimentation. One of the most important areas when designing haptic devices is the end-effector, since it is in contact with the user. In this thesis the design and evaluation of a thimble-like, lightweight, user-adaptable, and cost-effective device that incorporates four contact force sensors is described. This design allows estimation of the forces applied by a user during manipulation of virtual and real objects. The design of a real-time, modular control architecture for multi-finger haptic interaction is described. Requirements for control of multi-finger haptic devices are explored. Moreover, a large number of signals have to be acquired, processed, sent over the network and mathematical computations such as device direct and inverse kinematics, jacobian, grasp detection algorithms, etc. have to be calculated in Real Time to assure the required high fidelity for the haptic interaction. The Hardware control architecture has different modules and consists of an FPGA for the low-level controller and a RT controller for managing all the complex calculations (jacobian, kinematics, etc.); this provides a compact and scalable solution for the required high computation capabilities assuring a correct frequency rate for the control loop of 1 kHz. A set-up for dexterous virtual and real manipulation is described. Moreover, a new algorithm named the iterative kinematic decoupling method was implemented to solve the inverse kinematics of a robotic manipulator. In order to understand the importance of multi-modal interaction including haptics, a subject study was carried out to look for sensory stimuli that correlate with fast response time and enhanced accuracy. This experiment was carried out in collaboration with neuro-scientists from Technion Israel Institute of Technology. By comparing the grasping response times in unimodal (auditory, visual, and haptic) events with the response times in events with bimodal and trimodal combinations. It is concluded that in grasping tasks the synchronized motion of the fingers to generate the grasping response relies on haptic cues. This processing-speed advantage of haptic cues suggests that multimodalhaptic virtual environments are superior in generating motor contingencies, enhancing the plausibility of events. Applications that include haptics provide users with more time at the cognitive stages to fill in missing information creatively and form a richer experience. A major application of haptic devices is the design of new simulators to train manual skills for the medical sector. In collaboration with physical therapists from Griffith University in Australia, we developed a simulator to allow hand rehabilitation manipulations. First, the non-linear stiffness properties of the metacarpophalangeal joint of the index finger were estimated by using the designed end-effector; these parameters are implemented in a scenario that simulates the behavior of the human hand and that allows haptic interaction through the designed haptic device. The potential application of this work is related to educational and medical training purposes. In this thesis, new methods to simultaneously control the position and orientation of a robotic manipulator and the grasp of a robotic hand when interacting with large real environments are studied. The reachable workspace is extended by automatically switching between rate and position control modes. Moreover, the human hand gesture is recognized by reading the relative movements of the index, thumb and middle fingers of the user during the early stages of the approximation-to-the-object phase and then mapped to the robotic hand actuators. These methods are validated to perform dexterous manipulation of objects with a robotic manipulator, and different robotic hands. This work is the result of a research collaboration with researchers from the Harvard BioRobotics Laboratory. The developed experiments show that the overall task time is reduced and that the developed methods allow for full dexterity and correct completion of dexterous manipulations.

A Comunicação Mediada por Interfaces Digitais: a interação humana com os jogos digitais em celulares.

O trabalho é um estudo exploratório sobre o processamento de mensagens de entretenimento. O objetivo do trabalho foi propor e testar um modelo de processamento de mensagens dedicado à compreensão de jogos digitais. Para realizar tal tarefa realizou-se um extenso levantamento de técnicas de observação de usuários diante de softwares e mídias, para conhecer as qualidades e limitações de cada uma dessas técnicas, bem como de sua abordagem do problema. Também foi realizado um levantamento dos modelos de processamento de mensagens nas mídias tradicionais e nas novas mídias. Com isso foi possível propor um novo modelo de análise de processamento de mensagens de entretenimento. Uma vez criado o modelo teórico, fez-se preciso testar se os elementos propostos como participantes desse processo estavam corretos e se seriam capazes de capturar adequadamente as semelhanças e diferenças entre a interação entre jogadores e as diferentes mídias. Por essa razão, estruturou-se uma ferramenta de coleta de dados, que foi validada junto a designers de jogos digitais, uma vez que esses profissionais conhecem o processo de criação de um jogo, seus elementos e objetivos. Posteriormente, foi feito um primeiro teste, junto a praticantes de jogos digitais de diversas idades em computadores pessoais e TV digital interativa, a fim e verificar como os elementos do modelo relacionavam-se entre si. O teste seguinte fez a coleta de dados de praticantes de jogos digitais em aparelhos celulares, tendo como objetivo capturar como se dá a formação de uma experiência através do processamento da mensagem de entretenimento num meio cujas limitações são inúmeras: tamanho de tela e teclas, para citar algumas delas. Como resultado, verificou-se, por meio de testes estatísticos, que jogos praticados em meios como computadores pessoais atraem mais por seus aspectos estéticos, enquanto a apreciação de um jogo em aparelhos celulares depende muito mais de sua habilidade de manter a interação que um jogo praticado em PC. Com isso conclui-se que o processamento das mensagens de entretenimento depende da capacidade dos seus criadores em entender os limites de cada meio e usar adequadamente os elementos que compõe o ambiente de um jogo, para conseguir levar à apreciação do mesmo.(AU)

A Comunicação Mediada por Interfaces Digitais: a interação humana com os jogos digitais em celulares.

O trabalho é um estudo exploratório sobre o processamento de mensagens de entretenimento. O objetivo do trabalho foi propor e testar um modelo de processamento de mensagens dedicado à compreensão de jogos digitais. Para realizar tal tarefa realizou-se um extenso levantamento de técnicas de observação de usuários diante de softwares e mídias, para conhecer as qualidades e limitações de cada uma dessas técnicas, bem como de sua abordagem do problema. Também foi realizado um levantamento dos modelos de processamento de mensagens nas mídias tradicionais e nas novas mídias. Com isso foi possível propor um novo modelo de análise de processamento de mensagens de entretenimento. Uma vez criado o modelo teórico, fez-se preciso testar se os elementos propostos como participantes desse processo estavam corretos e se seriam capazes de capturar adequadamente as semelhanças e diferenças entre a interação entre jogadores e as diferentes mídias. Por essa razão, estruturou-se uma ferramenta de coleta de dados, que foi validada junto a designers de jogos digitais, uma vez que esses profissionais conhecem o processo de criação de um jogo, seus elementos e objetivos. Posteriormente, foi feito um primeiro teste, junto a praticantes de jogos digitais de diversas idades em computadores pessoais e TV digital interativa, a fim e verificar como os elementos do modelo relacionavam-se entre si. O teste seguinte fez a coleta de dados de praticantes de jogos digitais em aparelhos celulares, tendo como objetivo capturar como se dá a formação de uma experiência através do processamento da mensagem de entretenimento num meio cujas limitações são inúmeras: tamanho de tela e teclas, para citar algumas delas. Como resultado, verificou-se, por meio de testes estatísticos, que jogos praticados em meios como computadores pessoais atraem mais por seus aspectos estéticos, enquanto a apreciação de um jogo em aparelhos celulares depende muito mais de sua habilidade de manter a interação que um jogo praticado em PC. Com isso conclui-se que o processamento das mensagens de entretenimento depende da capacidade dos seus criadores em entender os limites de cada meio e usar adequadamente os elementos que compõe o ambiente de um jogo, para conseguir levar à apreciação do mesmo.(AU)

An investigation of the safety implications of wireless communications in vehicles.

"DOT HS 808-635"--P. [4] of cover.

A Comunicação Mediada por Interfaces Digitais: a interação humana com os jogos digitais em celulares.

O trabalho é um estudo exploratório sobre o processamento de mensagens de entretenimento. O objetivo do trabalho foi propor e testar um modelo de processamento de mensagens dedicado à compreensão de jogos digitais. Para realizar tal tarefa realizou-se um extenso levantamento de técnicas de observação de usuários diante de softwares e mídias, para conhecer as qualidades e limitações de cada uma dessas técnicas, bem como de sua abordagem do problema. Também foi realizado um levantamento dos modelos de processamento de mensagens nas mídias tradicionais e nas novas mídias. Com isso foi possível propor um novo modelo de análise de processamento de mensagens de entretenimento. Uma vez criado o modelo teórico, fez-se preciso testar se os elementos propostos como participantes desse processo estavam corretos e se seriam capazes de capturar adequadamente as semelhanças e diferenças entre a interação entre jogadores e as diferentes mídias. Por essa razão, estruturou-se uma ferramenta de coleta de dados, que foi validada junto a designers de jogos digitais, uma vez que esses profissionais conhecem o processo de criação de um jogo, seus elementos e objetivos. Posteriormente, foi feito um primeiro teste, junto a praticantes de jogos digitais de diversas idades em computadores pessoais e TV digital interativa, a fim e verificar como os elementos do modelo relacionavam-se entre si. O teste seguinte fez a coleta de dados de praticantes de jogos digitais em aparelhos celulares, tendo como objetivo capturar como se dá a formação de uma experiência através do processamento da mensagem de entretenimento num meio cujas limitações são inúmeras: tamanho de tela e teclas, para citar algumas delas. Como resultado, verificou-se, por meio de testes estatísticos, que jogos praticados em meios como computadores pessoais atraem mais por seus aspectos estéticos, enquanto a apreciação de um jogo em aparelhos celulares depende muito mais de sua habilidade de manter a interação que um jogo praticado em PC. Com isso conclui-se que o processamento das mensagens de entretenimento depende da capacidade dos seus criadores em entender os limites de cada meio e usar adequadamente os elementos que compõe o ambiente de um jogo, para conseguir levar à apreciação do mesmo.(AU)

Trajectory privacy preservation in mobile Wireless Sensor Networks

In recent years, there has been an enormous growth of location-aware devices, such as GPS embedded cell phones, mobile sensors and radio-frequency identification tags. The age of combining sensing, processing and communication in one device, gives rise to a vast number of applications leading to endless possibilities and a realization of mobile Wireless Sensor Network (mWSN) applications. As computing, sensing and communication become more ubiquitous, trajectory privacy becomes a critical piece of information and an important factor for commercial success. While on the move, sensor nodes continuously transmit data streams of sensed values and spatiotemporal information, known as ``trajectory information". If adversaries can intercept this information, they can monitor the trajectory path and capture the location of the source node. ^ This research stems from the recognition that the wide applicability of mWSNs will remain elusive unless a trajectory privacy preservation mechanism is developed. The outcome seeks to lay a firm foundation in the field of trajectory privacy preservation in mWSNs against external and internal trajectory privacy attacks. First, to prevent external attacks, we particularly investigated a context-based trajectory privacy-aware routing protocol to prevent the eavesdropping attack. Traditional shortest-path oriented routing algorithms give adversaries the possibility to locate the target node in a certain area. We designed the novel privacy-aware routing phase and utilized the trajectory dissimilarity between mobile nodes to mislead adversaries about the location where the message started its journey. Second, to detect internal attacks, we developed a software-based attestation solution to detect compromised nodes. We created the dynamic attestation node chain among neighboring nodes to examine the memory checksum of suspicious nodes. The computation time for memory traversal had been improved compared to the previous work. Finally, we revisited the trust issue in trajectory privacy preservation mechanism designs. We used Bayesian game theory to model and analyze cooperative, selfish and malicious nodes' behaviors in trajectory privacy preservation activities.^

Os efeitos das reclamações online na lealdade dos consumidores: um estudo experimental

In an environment of constant change, technological developments, market competition and more informed consumers, the search for a lasting relationship through the conquest of loyalty has become the objective of companies. However, several authors suggest that this loyalty can be affected by negative comments available on the internet. Therefore, this dissertation has as objective to examine if the complaints are available on the internet impact the loyalty to a brand of mobile phone. The research used as the basis the Expanded NCSB model suggest by Johnson et al. (2001), studying five prominent drives of loyalty: image/brand reputation, affective commitment, calculative commitment, perceived value and trust, beyond the satisfaction construct as moderator variable. The research method adopted was the experimental design which included 285 undergraduate students, with the trial which included 285 undergraduate students, with the field study of the mobile industry, specifically, the brands of cell phones. The research approach was quantitative and methods were descriptive statistics, factor analysis, cluster analysis, linear regression and non-parametric test of Wilcoxon for data analysis. Of the 16 hypothesis stemmed from the research model proposed, 12 were confirmed. The results showed that the complaint available on the internet, here represented by the available on the site Reclame Aqui, may impact consumer perceptions about brand loyalty, as well as its antecedents, being that these complaints can affect all the consumers, regardless of historical satisfaction with the brand. It also noted the positive relationship between the independent variables trust, image/brand reputation, perceived value, affective commitment and calculative commitment and the dependent variable - loyalty, even when considering the data obtained after exposure to the complaint. However, no unanimous conclusion that the relationship between these variables was strongest in the group with satisfactory experience. At the first moment of the research, the trust was the most important variable for the formation of loyalty. However, after exposure to treatment, the image/brand reputation, was more relevant. Contributions of the study, limitations and recommendations for future researches are approached in the present investigation

Exploring Forensic Nursing Ethics and Practice: Roles, Loyalties and Photodocumentation Practices

Thesis (Ph.D.)--University of Washington, 2016-08

An Adaptive and Hybrid Approach to Revisiting the Visibility Pipeline

We revisit the visibility problem, which is traditionally known in Computer Graphics and Vision fields as the process of computing a (potentially) visible set of primitives in the computational model of a scene. We propose a hybrid solution that uses a dry structure (in the sense of data reduction), a triangulation of the type , to accelerate the task of searching for visible primitives. We came up with a solution that is useful for real-time, on-line, interactive applications as 3D visualization. In such applications the main goal is to load the minimum amount of primitives from the scene during the rendering stage, as possible. For this purpose, our algorithm executes the culling by using a hybrid paradigm based on viewing-frustum, back-face culling and occlusion models. Results have shown substantial improvement over these traditional approaches if applied separately. This novel approach can be used in devices with no dedicated processors or with low processing power, as cell phones or embedded displays, or to visualize data through the Internet, as in virtual museums applications.

No right to sext? A critical examination of media and legal debates about teenage girls' sexual agency in the digital age

Advances in digital photography and distribution technologies enable many people to produce and distribute images of their sex acts. When teenagers do this, the photos and videos they create can be legally classified as child pornography since the law makes no exception for youth who create sexually explicit images of themselves. The dominant discussions about teenage girls producing sexually explicit media (including sexting) are profoundly unproductive: (1) they blame teenage girls for creating private images that another person later maliciously distributed and (2) they fail to respect—or even discuss—teenagers’ rights to freedom of expression. Cell phones and the internet make producing and distributing images extremely easy, which provide widely accessible venues for both consensual sexual expression between partners and for sexual harassment. Dominant understandings view sexting as a troubling teenage trend created through the combination of camera phones and adolescent hormones and impulsivity, but this view often conflates consensual sexting between partners with the malicious distribution of a person’s private image as essentially equivalent behaviors. In this project, I ask: What is the role of assumptions about teen girls’ sexual agency in these problematic understandings of sexting that blame victims and deny teenagers’ rights? In contrast to the popular media panic about online predators and the familiar accusation that youth are wasting their leisure time by using digital media, some people champion the internet as a democratic space that offers young people the opportunity to explore identities and develop social and communication skills. Yet, when teen girls’ sexuality enters this conversation, all this debate and discussion narrows to a problematic consensus. The optimists about adolescents and technology fall silent, and the argument that media production is inherently empowering for girls does not seem to apply to a girl who produces a sexually explicit image of herself. Instead, feminist, popular, and legal commentaries assert that she is necessarily a victim: of a “sexualized” mass media, pressure from her male peers, digital technology, her brain structures or hormones, or her own low self-esteem and misplaced desire for attention. Why and how are teenage girls’ sexual choices produced as evidence of their failure or success in achieving Western liberal ideals of self-esteem, resistance, and agency? Since mass media and policy reactions to sexting have so far been overwhelmingly sexist and counter-productive, it is crucial to interrogate the concepts and assumptions that characterize mainstream understandings of sexting. I argue that the common sense that is co-produced by law and mass media underlies the problematic legal and policy responses to sexting. Analyzing a range of nonfiction texts including newspaper articles, talk shows, press releases, public service announcements, websites, legislative debates, and legal documents, I investigate gendered, racialized, age-based, and technologically determinist common sense assumptions about teenage girls’ sexual agency. I examine the consensus and continuities that exist between news, nonfiction mass media, policy, institutions, and law, and describe the limits of their debates. I find that this early 21st century post-feminist girl-power moment not only demands that girls live up to gendered sexual ideals but also insists that actively choosing to follow these norms is the only way to exercise sexual agency. This is the first study to date examining the relationship of conventional wisdom about digital media and teenage girls’ sexuality to both policy and mass media.

Os efeitos das reclamações online na lealdade dos consumidores: um estudo experimental

In an environment of constant change, technological developments, market competition and more informed consumers, the search for a lasting relationship through the conquest of loyalty has become the objective of companies. However, several authors suggest that this loyalty can be affected by negative comments available on the internet. Therefore, this dissertation has as objective to examine if the complaints are available on the internet impact the loyalty to a brand of mobile phone. The research used as the basis the Expanded NCSB model suggest by Johnson et al. (2001), studying five prominent drives of loyalty: image/brand reputation, affective commitment, calculative commitment, perceived value and trust, beyond the satisfaction construct as moderator variable. The research method adopted was the experimental design which included 285 undergraduate students, with the trial which included 285 undergraduate students, with the field study of the mobile industry, specifically, the brands of cell phones. The research approach was quantitative and methods were descriptive statistics, factor analysis, cluster analysis, linear regression and non-parametric test of Wilcoxon for data analysis. Of the 16 hypothesis stemmed from the research model proposed, 12 were confirmed. The results showed that the complaint available on the internet, here represented by the available on the site Reclame Aqui, may impact consumer perceptions about brand loyalty, as well as its antecedents, being that these complaints can affect all the consumers, regardless of historical satisfaction with the brand. It also noted the positive relationship between the independent variables trust, image/brand reputation, perceived value, affective commitment and calculative commitment and the dependent variable - loyalty, even when considering the data obtained after exposure to the complaint. However, no unanimous conclusion that the relationship between these variables was strongest in the group with satisfactory experience. At the first moment of the research, the trust was the most important variable for the formation of loyalty. However, after exposure to treatment, the image/brand reputation, was more relevant. Contributions of the study, limitations and recommendations for future researches are approached in the present investigation