Optimal Location of Distributed Generation Sources and Capacitance of Distribution Network to Reduce Losses, Improve Voltage Profile, and Minimizing the Costs Using Genetic and Harmonic Search Algorithm

International audienceReducing losses and improving the voltage profile have been the main objectives of electrical power system designers. One of the suggested solutions for achieving these goals is the use of parallel capacitors and distributed generation sources in distribution systems. A location that is optimized for DG installation may not be the best place to minimize losses in improving the system voltage profile. In this paper, determining the optimal location of the dispersed generation unit and the capacitive bank with the goal of optimizing a target function, including losses, improving the voltage profile, and the cost of investment in capacitors and dispersed production. In this paper, IEEE standard 33 buses is considered for simulation, and the results are obtained by using genetic and harmonic search algorithm indicate that DG optimization and capacitor with a target function in which the loss reduction and improvement of the voltage profile is considered to reduce costs, reduce losses, and improve the voltage profile, which are remarkable improvements

Banco de testes para monitoramento sub-Nyquist de espectro de banda larga

Radioelectric spectrum management is a concern for today’s world, mainly due to the misuse that has been given to this resource through the years, especially on the UHF band. To address this problem, a testbed for sub-Nyquist Wideband Spectrum Monitoring was built, that includes a web interface to remotely measure occupancy of the UHF band. To achieve the above, an RF interface that allows tuning UHF frequencies with an instantaneous bandwidth of 95 MHz was built. Afterwards, a Random Demodulator was connected, and then an embedded system performed sub--Nyquist sampling and spectrum recovery. The embedded system connected to an information system that serves a web page, through which remote users can perform UHF band monitoring. Experimental results showed that spectrum sensing can be achieved by using different algorithms on certain sparse spectra. In addition, the aforementioned web interface allowed simultaneous user connections, in order to perform independent measurements by sharing a hardware subsystem.La gestión del espectro radioeléctrico es una preocupación en la actualidad, hecho derivado, ante todo, del mal uso que se ha dado a este recurso a través de los años, especialmente en la banda de UHF. Para afrontar este problema, se construyó un banco de pruebas para la supervisión del espectro de banda ancha a través de muestreo sub-Nyquist, el cual incluye una interfaz web para medir de forma remota la ocupación de la banda UHF. Para lograr esto, se construyó una interfaz RF que permitiría sintonizar frecuencias UHF con un ancho de banda instantáneo de 95 MHz. Después, se conectó un demodulador aleatorio; y luego, un sistema embebido realizaría el muestreo sub-Nyquist y la recuperación del espectro. Este se conectaría, a su turno, con un sistema de información que sirve una página web, a través de la cual los usuarios remotos pueden realizar la supervisión de la banda de UHF. Los resultados muestran que la detección del espectro se puede lograr mediante diferentes algoritmos en ciertos espectros dispersos. Además, la interfaz web permitió que existiesen conexiones de usuario simultáneas, de tal manera que se realizaran mediciones independientes compartiendo el subsistema de hardware.O gerenciamento do espectro radioelétrico é uma preocupação na atualidade, fato derivado, inicialmente, do mau uso que se tem dado a esse recurso através dos anos, especialmente na banda de UHF. Para enfrentar esse problema, construiu-se um banco de testes para a supervisão do espectro de banda larga por meio de amostragem sub-Nyquist, a qual inclui uma interface web para medir de forma remota a ocupação da banda UHF. Para isso, construiu-se uma interface RF que permitiria sintonizar frequências UHF com uma largura de banda instantânea de 95 MHz. Em seguida, ligou-se um demodulador aleatório; logo, um sistema embebido realizaria a amostragem sub-Nyquist e a recuperação do espectro. Este se ligaria, por sua vez, com um sistema de informação que serve um site, através do qual os usuários remotos podem realizar a supervisão da banda de UHF. Os resultados mostram que a detecção do espectro pode ser conseguida mediante diferentes algoritmos em certos espectros dispersos. Além disso, a interface web permitiu que existissem conexões de usuário simultâneas, de tal maneira que se realizassem medidas independentes compartilhando o subsistema de hardware.&nbsp

Active inductor-based tunable impedance matching network for RF power amplifier application

This paper presents the use of a new structure of active inductor named cascoded flipped-active inductor (CASFAI) in a T-type high-pass tunable output matching network of a class-E RF power amplifier (RFPA) to control the output power and enhance the efficiency. The designed CASFAI behaves as an inductor in the frequency range of 0–6.9 GHz, and has reached to a maximum quality factor of 4406, inductance value of 7.56 nH, 3rd order harmonic distortion better than -30 dB for 0 dBm input power, while consumes only 2 mW power. In order to consider the performance of the proposed active inductor-based tunable output matching network on the output power level and power added efficiency (PAE) of RFPA, the CASFAI is applied as a variable inductor to the output matching network of RFPA. The overall circuit is designed and validated in ADS in a 0.18 µm CMOS process and 1.5 V supply voltage. The results indicate that by increasing the inductance value of the matching network in constant operating frequency, the PAE peak moves from high power to low power levels without any degradation. Therefore, it is possible to maintain the power efficiency at the same maximum level for lower input drive levels.Peer ReviewedPostprint (author's final draft

Interfaz humano-computador basada en gestos faciales y orientada a la aplicación WhatsApp para personas con limitación motriz de miembros superiores

People with reduced upper-limb mobility depend mainly on facial gestures to communicate with the world; nonetheless, current facial gesture-based interfaces do not take into account the reduction in mobility that most people with motor limitations experience during recovery periods. This study presents an alternative to overcome this limitation, a human-computer interface based on computer vision techniques over two types of images: images of the user’s face captured by a webcam and screenshots of a desktop application running on the foreground. The first type is used to detect, track, and estimate gestures, facial patterns in order to move and execute commands with the cursor, while the second one is used to ensure that the cursor moves to specific interaction areas of the desktop application. The interface was fully programmed in Python 3.6 using open source libraries and runs in the background in Windows operating systems. The performance of the interface was evaluated with videos of people using four interaction commands in WhatsApp Desktop. We conclude that the interface can operate with various types of lighting, backgrounds, camera distances, body postures, and movement speeds; and the location and size of the WhatsApp window does not affect its effectiveness. The interface operates at a speed of 1 Hz and uses 35 % of the capacity a desktop computer with an Intel Core i5 processor and 1.5 GB of RAM for its execution; therefore, this solution can be implemented in ordinary, low-end personal computers.En el caso de personas con limitación motriz de miembros superiores, los gestos faciales son la principal forma de comunicarse con el mundo. Sin embargo, las interfaces actuales basadas en gestos no tienen en cuenta la reducción de movilidad que la mayoría de las personas con limitación motriz experimentan durante sus periodos de recuperación. Como alternativa para superar esta limitación, se presenta una interfaz humana-computador basada en técnicas de visión por computador sobre dos tipos de imagen: la imagen del rostro capturada mediante webcam y la captura de pantalla de una aplicación de escritorio en primer plano. La primera imagen es utilizada para detectar, seguir y estimar la pose del rostro con el fin de desplazar y ejecutar comandos con el cursor; la segunda imagen es utilizada para lograr que los desplazamientos del cursor sean realizados a zonas específicas de interacción de la aplicación de escritorio. La interfaz es programada totalmente en Python 3.6 utilizando bibliotecas de código abierto y se ejecuta en segundo plano dentro del sistema operativo Windows. El desempeño de la interfaz se evalúa con videos de personas utilizando cuatro comandos de interacción con la aplicación WhatsApp versión de escritorio. Se encontró que la interfaz puede operar con varios tipos de iluminación, fondos, distancias a la cámara, posturas y velocidades de movimiento; la ubicación y el tamaño de la ventana de WhatsApp no afecta la efectividad de la interfaz. La interfaz opera a una velocidad de 1 Hz y utiliza el 35 % de la capacidad de un procesador Intel Core i5 y 1,5 GB de RAM para su ejecución lo que permite concebir esta solución en equipos de cómputo personales

Development of a virtual reality ophthalmoscope prototype

El examen visual es un procedimiento importante que proporciona información acerca de la condición del fondo de ojo, permitiendo la observación e identificación de anomalías, como ceguera, diabetes, hipertensión, sangrados resultado de traumas, entre otros. Un apropiado examen permite identificar condiciones que pueden comprometer la visión, sin embargo, éste es desafiante porque requiere de una práctica extensiva para desarrollar las habilidades para una adecuada interpretación que permiten la identificación exitosa de anomalías en el fondo de ojo con un oftalmoscopio. Para ayudar a los practicantes a desarrollar sus habilidades para la examinación ocular, los dispositivos de simulación médica están ofreciendo oportunidades de entrenamiento para explorar numerosos casos del ojo en escenarios simulados, controlados y monitoreados. Sin embargo, los avances en la simulación del ojo han llevado a costosos simuladores con acceso limitado ya que la práctica se mantiene con interacciones para un aprendiz y en algunos casos, ofreciendo al entrenador la visión para la interacción del practicante. Gracias a los costos asociados a la simulación médica, hay varias alternativas reportadas en la revisión de la literatura, presentando aproximaciones efectividad-costo y nivel de consumo para maximizar la efectividad del entrenamiento para el examen de ojo. En este trabajo se presenta el desarrollo de una aplicación con realidad aumentada inmersiva y no-inmersiva, para dispositivos móviles Android con interacciones a través de un controlador impreso en 3D con componentes electrónicos embebidos que imitan a un oftalmoscopio real. La aplicación presenta a los usuarios un paciente virtual visitando al doctor para un examen ocular, y requiere que el aprendiz ejecute el examen de fondo de ojo haciendo diagnosticando sus hallazgos. La versión inmersiva de la aplicación requiere del uso de un casco de realidad virtual, además del prototipo 3D de oftalmoscopio, mientras que la no inmersiva, requiere únicamente del marcador dentro del campo de visión del dispositivo móvil.The eye examination is an important procedure that provides information about the condition of the eye by observing its fundus, thus allowing the observation and identification of abnormalities, such as blindness, diabetes, hypertension, and bleeding resulting from traumas among others. A proper eye fundus examination allows identifying conditions that may compromise the sight; however, the eye examination is challenging because it requires extensive practice to develop adequate interpretation skills that allows successfully identifying abnormalities at the back of the eye seen through an ophthalmoscope. To assist trainees in developing the eye examination skills, medical simulation devices are providing training opportunities to explore numerous eye cases in simulated, controlled, and monitored scenarios. However, advances in eye simulation have led to expensive simulators with limited access as practice remain conducted on a one trainee basis in some cases offering the instructor a view of the trainee interactions. Because of the costs associated with medical simulation, there various alternatives reported in the literature review presenting cost-effective and consumerlevel approaches to maximize the effectiveness of the eye examination training. In this work, we present the development an immersive and non-immersive augmented reality application for Android mobile devices with interactions through a 3D printed controller with embedded electronic components that mimics a real ophthalmoscope. The application presents users with a virtual patient visiting the doctor for an eye examination, and requires the trainees to perform the eye fundus examination and diagnose their findings. The immersive version of the application requires the trainees to wear a mobile VR headset and hold the 3D printed ophthalmoscope, while the non-immersive version requires them to hold the marker within the field of view of the mobile device.Pregrad

E-BOOT: Preventing Boot-Time Entropy

[EN] Due to the impracticability of generating true randomness by running deterministic algorithms in computers, boot-loaders and operating systems undergo the lack of enough supplies of entropy at boot-time. This problem remains a challenge and affects all computer systems, including virtualization technologies. Unfortunately, this situation leads to undesired side effects, affecting the security of important kernel components and causing large blocking waits in the start-up of userland processes. For example, SSHD is delayed up to 4 minutes. In this paper, we analyze the boot-time entropy starvation problem, performing a comprehensive analysis of the Linux kernel boot process revealing that the problem not only affects userland applications but up to 33 kernel functions at boot time. Those functions are weakly fed by random numbers from a non-initialized CSPRNG. To overcome this problem, we propose E-Boot, a novel technique that provides high-quality random numbers to guest virtual machines. E-Boot is the first technique that completely satisfies the entropy demand of virtualized boot-loaders and operating systems at boot time. We have implemented E-Boot in Linux v5.3 and our experiments show that it effectively solves the boot-time entropy starvation problem. Our proposal successfully feeds bootloaders and boot time Linux kernel hardening techniques with high-quality random numbers, reducing also to zero the number of userspace blocks and delays. The total time overhead introduced by E-Boot is around 2 mu s and has zero memory overhead, since the memory is freed before the kernel boot ends, which makes E-boot a practical solution for cloud systems.Vañó-García, F.; Marco-Gisbert, H. (2020). E-BOOT: Preventing Boot-Time Entropy. IEEE Access. 8:61872-61890. https://doi.org/10.1109/ACCESS.2020.2984414S6187261890

Ethical Hacking Using Penetration Testing

This thesis provides details of the hardware architecture and the software scripting, which are employed to demonstrate penetration testing in a laboratory setup. The architecture depicts an organizational computing asset or an environment.¬¬¬ With the increasing number of cyber-attacks throughout the world, the network security is becoming an important issue. This has motivated a large number of “ethical hackers” to indulge and develop methodologies and scripts to defend against the security attacks. As it is too onerous to maintain and monitor attacks on individual hardware and software in an organization, the demand for the new ways to manage security systems invoked the idea of penetration testing. Many research groups have designed algorithms depending on the size, type and purpose of application to secure networks [55]. In this thesis, we create a laboratory setup replicating an organizational infrastructure to study penetration testing on real time server-client atmosphere. To make this possible, we have used Border Gateway Protocol (BGP) as routing protocol as it is widely used in current networks. Moreover, BGP exhibits few vulnerabilities of its own and makes the security assessment more promising. Here, we propose (a) computer based attacks and (b) actual network based attacks including defense mechanisms. The thesis, thus, describes the way penetration testing is accomplished over a desired BGP network. The procedural generation of the packets, exploit, and payloads involve internal and external network attacks. In this thesis, we start with the details of all sub-fields in the stream of penetration testing, including their requirements and outcomes. As an informative and learning research, this thesis discusses the types of attacks over the routers, switches and physical client machines. Our work also deals with the limitations of the implementation of the penetration testing, discussing over the vulnerabilities of the current standards in the technology. Furthermore, we consider the possible methodologies that require attention in order to accomplish most efficient outcomes with the penetration testing. Overall, this work has provided a great learning opportunity in the area of ethical hacking using penetration testing

A User Authentication Scheme Using Physiological and Behavioral Biometrics for Multitouch Devices

With the rapid growth of mobile network, tablets and smart phones have become sorts of keys to access personal secured services in our daily life. People use these devices to manage personal finances, shop on the Internet, and even pay at vending machines. Besides, it also helps us get connected with friends and business partners through social network applications, which were widely used as personal identifications in both real and virtual societies. However, these devices use inherently weak authentication mechanism, based upon passwords and PINs that is not changed all the time. Although forcing users to change password periodically can enhance the security level, it may also be considered annoyances for users. Biometric technologies are straightforward because of the simple authentication process. However, most of the traditional biometrics methodologies require diverse equipment to acquire biometric information, which may be expensive and not portable. This paper proposes a multibiometric user authentication scheme with both physiological and behavioral biometrics. Only simple rotations with fingers on multitouch devices are required to enhance the security level without annoyances for users. In addition, the user credential is replaceable to prevent from the privacy leakage

SmartGuia: Shopping Assistant for Blind People

Dissertação de Mestrado Integrado em Engenharia Biomédica apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra.Tendo em conta as limita c~oes das pessoas com de ci^encia, o presente trabalho pretende agir num cen ario espec co melhorando a qualidade da vidas destas pessoas. Integrados num grupo de investiga c~ao em Internet das Coisas, colabor amos com tr^es institui c~oes, levantando requisitos no que concerne a aplicabilidade da Internet das Coisas para ajudar pessoas com de ci^encia. Depois disso, escolhemos e foc amo-nos no plano de trabalho adotado, sendo um dos cen arios identi cados onde poder amos ajudar. Com este trabalho e proposto um sistema para apoiar pessoas cegas na ida as compras e navega c~ao dentro de edif cios. O sistema proposto ajuda o utilizador a circular pelo edif cio e encontrar servi cos e produtos desejados ou dispon veis. Tem como objetivo aumentar a autonomia das pessoas cegas nas atividades do dia-a-dia dentro de edif cios. A pessoa cega n~ao tem acesso a informa c~ao dispon vel por meios visuais. O sistema consiste numa aplica c~ao para smartphone que oferece navega c~ao assistida em edif cios p ublicos, respondendo a quest~oes, guiando a pessoa, e disponibilizando informa c~ao objetiva sobre os espa cos, servi cos e produtos dispon veis. O sistema proposto inclui tamb em um sistema de informa c~ao. Este sistema de informa c~ao identi ca o destino pretendido e oferece informa c~ao concisa ou detalhada sobre os produtos ou sevi cos dispon veis. O sistema determina constantemente a localiza c~ao do utilizador, calcula rotas, guia a pessoa dentro do edif cio, e identi ca pontos de interesse na vizinhan ca da pessoa. O sistema requer tecnologia de localiza c~ao por beacons, que poder~ao por sua ver ser baseados nas tecnologias Bluetooth ou Wi-Fi. Relativamente ao estado da arte, a nossa solu c~ao oferece vantagens importantes: minimiza a intera c~ao com o utilizador, que seria necess aria para escolher destinos, produtos ou servios desejados em outros sistemas; lida com o ambiente din^amico resultxi ante da caminhada do utilizador, como a varia c~ao do n umero e posi c~ao de beacons ao alcance do utilizador; utiliza dispositivos que a pessoa cega j a possui, e eventualmente beacons que possam j a existir ou tenham uma custo de implanta c~ao baixo. Al em destas vantagens, desenh amos o sistema de forma a ser o mais f acil e intuitivo de utilizar poss vel, aplicando mecanismos acess veis a pessoas cegas. Para al em disso, o sistema est a desenhado para lidar com o dinamismo do caminhar, sendo que o n umero e posi c~ao dos beacons varia