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A framework for network traffic analysis using GPUs

During the last years the computer networks have become an important part of our society. Networks have kept growing in size and complexity, making more complex its management and traffic monitoring and analysis processes, due to the huge amount of data and calculations involved. In the last decade, several researchers found effective to use graphics processing units (GPUs) rather than a traditional processors (CPU) to boost the execution of some algorithms not related to graphics (GPGPU). In 2006 the GPU chip manufacturer NVIDIA launched CUDA, a library that allows software developers to use their GPUs to perform general purpose algorithm calculations, using the C programming language. This thesis presents a framework which tries to simplify the task of programming network traffic analysis with CUDA to software developers. The objectives of the framework have been abstracting the task of obtaining network packets, simplify the task of creating network analysis programs using CUDA and offering an easy way to reuse the analysis code. Several network traffic analysis have also been developed

Design of an Embedded Readout System for the ALOFT Gamma-Ray Detector Instrument

Birkeland Center for Space Science has proposed a campaign known as the Airborne Lightning Observatory for FEGS & TGFs (ALOFT) to study Terrestrial Gamma-Ray Flashes (TGFs). TGFs are the most energetic natural phenomena occurring in the Earth’s atmosphere, and are important to our knowledge about the relationship between the Earth and space. The ALOFT campaign will use a gamma-ray detector instrument built by the University of Bergen which will be mounted to the NASA ER-2 High-Altitude Airborne Science Aircraft. This work covers the design and development of the embedded software used to offload and operate the detector readout system of said instrument. A similar instrument was built and flown in 2017. The new instrument differs from this by being implemented on a System on a Chip (SoC) embedded platform, reusing relevant modules from the old instrument. The software has been implemented with the FreeRTOS Realtime Operating System (RTOS). Design considerations to limit complexity, and the impact of the radiation environment the instrument is to be operated in, has been performed trough implementation of a checksum algorithm, cyclic rewriting of registers, and modular design strategies. A verification system has been realized with a prototype hardware setup, in which test systems has been added to process synthetic TGF-events in the software and hardware. Test with emulated data and a Telnet control interface has been successfully implemented. The current implementation focuses on modularity, and thus offers a very good framework for further development of the instrument when campaign specifications are decided.Masteroppgåve i fysikkMAMN-PHYSPHYS39

Automatic transmit power control for power efficient communications in UAS

Nowadays, unmanned aerial vehicles (UAV) have become one of the most popular tools that can be used in commercial, scientific, agricultural and military applications. As drones become faster, smaller and cheaper, with the ability to add payloads, the usage of the drone can be versatile. In most of the cases, unmanned aerials systems (UAS) are equipped with a wireless communication system to establish a link with the ground control station to transfer the control commands, video stream, and payload data. However, with the limited onboard calculation resources in the UAS, and the growing size and volume of the payload data, computational complex signal processing such as deep learning cannot be easily done on the drone. Hence, in many drone applications, the UAS is just a tool for capturing and storing data, and then the data is post-processed off-line in a more powerful computing device. The other solution is to stream payload data to the ground control station (GCS) and let the powerful computer on the ground station to handle these data in real-time. With the development of communication techniques such as orthogonal frequency-division multiplexing (OFDM) and multiple-input multiple-output (MIMO) transmissions, it is possible to increase the spectral efficiency over large bandwidths and consequently achieve high transmission rates. However, the drone and the communication system are usually being designed separately, which means that regardless of the situation of the drone, the communication system is working independently to provide the data link. Consequently, by taking into account the position of the drone, the communication system has some room to optimize the link budget efficiency. In this master thesis, a power-efficient wireless communication downlink for UAS has been designed. It is achieved by developing an automatic transmit power control system and a custom OFDM communication system. The work has been divided into three parts: research of the drone communication system, an optimized communication system design and finally, FPGA implementation. In the first part, an overview on commercial drone communication schemes is presented and discussed. The advantages and disadvantages shown are the source of inspiration for improvement. With these ideas, an optimized scheme is presented. In the second part, an automatic transmit power control system for UAV wireless communication and a power-efficient OFDM downlink scheme are proposed. The automatic transmit power control system can estimate the required power level by the relative position between the drone and the GCS and then inform the system to adjust the power amplifier (PA) gain and power supply settings. To obtain high power efficiency for different output power levels, a searching strategy has been applied to the PA testbed to find out the best voltage supply and gain configurations. Besides, the OFDM signal generation developed in Python can encode data bytes to the baseband signal for testing purpose. Digital predistortion (DPD) linearization has been included in the transmitter’s design to guarantee the signal linearity. In the third part, two core algorithms: IFFT and LUT-based DPD, have been implemented in the FPGA platform to meet the real-time and high-speed I/O requirements. By using the high-level synthesis design process provided by Xilinx Corp, the algorithms are implemented as reusable IP blocks. The conclusion of the project is given in the end, including the summary of the proposed drone communication system and envisioning possible future lines of research

Energy-aware Software

Luca Ardito has focused his PhD on studying how to identify and to reduce the energy consumption caused by software. The project concentrates on the application level, with an experimental approach to discover and modify characteristics that waste energy. We can define five research goals: RG1. Is it possible to measure the energy consumption of an application? Measuring the energy consumption of an electronic device (PC, mobile phone, etc.) is straightforward, but several applications coexist on it, possibly with very different energy needs. Usage profiles for applications are certainly important too. We will consider the most common platforms (Windows, Linux, Mac Osx). RG2. Could Energy Efficiency be considered as a software non- functional requirement? Research has increasingly focused on improving the Energy Efficiency of hardware, but the literature still lacks in quantifying accurately the energy impact of software. This research goal is strictly related to the following one. RG3. Is it possible to profile the energy consumption of a software application? An empirical experiment could assess quantitatively the energetic impact of software usage by building up common application usage scenarios and executing them independently to collect power consumption data. RG4. Is there a relationship between the way a program is written and its energy consumption? The same application, at the code level, can be written in different ways. Here the question is if the different ways have impact on energy consumption. The code should be considered at two levels: source code (programmer) and object code/byte code (compiler). RG5. Is it possible to use the energy consumption information to trigger self-adaptation? A software application could automatically modify its behaviour in order to reduce its energy consumption

The Development of a Frequency Control System of a Seeded Laser for DGV Application

For an effective Doppler Global Velocimeter (DGV), there is a requirement to accurately record and tune the frequency content of the laser used. The laser used for this experiment was an ND:YAG. Adjusting the mean frequency of the ND:YAG is accomplished by controlling the seed laser diode output, which also narrows the bandwidth of the laser to below 20 MHz. The exact frequency of operation is critical for the operation of the system. Standard interferometry techniques that measure laser frequency content, such as Fabre-Perot and grating based systems, are not able to provide an adequate spectrum resolution for the 9 ns pulse duration of the ND:YAG laser. A method was developed that employs a CCD line camera and a laser reference cell to effectively and cost efficiently solve this problem. The hardware and software for this real time monitoring system were developed and used with a real time feedback loop to stabilize the laser operating frequency at a specified value. The receiving optics of this DGV system were upgraded with 12 bit CCD cameras and a temperature controlled laser reference cell to decrease the uncertainty to the velocity measurement from over 4 m/s to less than 1 m/s. Recommendations to the effectiveness of the system and future improvements are provided