Despite the destructive and limited nature of fossil fuels, most human-made systems are dependent on the use of oil, gas and coal. Especially agriculture relies on diesel machinery, fertilizer, transport, and cooling systems that are commonly powered by non-renewable energy sources. This independent project in design specifically focuses on the dependency on fossil fuels within agriculture. With the investigation “Vägen mot fossiloberoende jordbruk” (Utredningen om fossiloberoende jordbruk, 2021), or “Pathway to fossil independent agriculture”, Sweden is aspiring to make farming fossil-free by 2030. Consequently, a lot of responsibility to invest in new technologies and alternative energies lies on farmers. In collaboration with Länsstyrelsen Kronoberg, the author explores how farmers can be supported to transition towards renewable energies, focusing on the Swedish region Kronoberg. Through participatory design and design research, notions of fossil fuel (in)dependency are being explored in collaborative ways. Here, the farmers become the ‘experts of their experience’ (Sanders & Stappers, 2012). This independent design project examines ways to transition towards fossil fuel independent agriculture in Sweden, existing challenges and potential solutions. To communicate the complex network of energy and agriculture in Kronoberg to Länsstyrelsen, the author designed an Actor-Network-Model, which highlights the necessity of systems thinking and collaboration.

Distributed computing is very popular in the field of computer science and is widely used in web applications. In such systems, tasks and resources are partitioned among several computers so that the workload can be shared among the different computers in the network, in contrast to systems using a single server computer. Distributed system designs are used for many practical reasons and are often found to be more scalable, robust and suitable for many applications. The aim of this thesis is to study the properties of a distributed tree data-structure that allow searches, insertions and deletions of data elements. In particular, the b- tree structure [13] is considered, which is a generalization of a binary search tree. The study consists of analyzing the effect of distributing such a tree among several computers and investigates the behavior of such structure over a long period of time by growing the network of computers supporting the tree, while the state of the structure is instantly updated as insertions and deletions operations are performed. It also attempts to validate the necessary and sufficient invariants of the b-tree-structure that guarantee the correctness of the search operations. A simulation study is also conducted to verify the validity of such distributed data-structure and the performance of the algorithm that implements it. Finally, a discussion is provided in the end of the thesis to compare the performance of the system design with other distributed tree structure designs.

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This thesis examines the problem of providing high data-rate wireless connectivity to users in indoor environments. The goal is to be able to reach Gbps/user rates even when there are multiple users present. The technology that we study is to use the 60 GHz spectrum whose special propagation properties make it ideally suited to this task. The approaches developed include using multiple spatially distributed smart antennas in a room or multiple co-located antennas to provide coverage where needed and when needed. All the antennas are connected to a single access point which allows us to dynamically change spectrum and link allocation among the users (as they move or as their needs change). The innovations in this work include the exploitation of the special properties of 60 GHz and the corresponding design of algorithms for efficient spectrum allocation. We use detailed simulations to demonstrate that very high data rates are indeed achievable.

This thesis investigates the development of a low-cost passive acoustic system for localizing moving vessels to monitor areas where human activities such as fishing, snorkeling and poaching are restricted. The system uses several off-the-shelf sensors with unsynchronized clocks where the Time Difference of Arrival (TDOA) or time delay is extracted by cross-correlation of the signal between paired sensors. The cross-correlation function uses phase correlation or Phase Transform (PHAT) which whitens the cross-spectrum in order to de-emphasize dominant frequency components. Using the locations of pairs of sensors as foci, hyperbolic equations can be defined using the time delay between them. With three or more sensors, multiple hyperbolic functions can be calculated which intersect at a unique point: the boat's location. It is also found that increasing separation distances between sensors decreased the correlation between the signals. However larger separation distances have better localization capability than with small distances. Experimental results from the Columbia and Willamette Rivers are presented to demonstrate performance.

Unmanned aerial vehicles (UAV's) have recently gained popularity in military, civil service, agriculture, commercial, and hobby use. This is due in part to their affordability, which comes from advances in component technology. That technology includes microelectromechanical systems (MEMS) for inertial sensing, microprocessor technology for sequential algorithm processing, field programmable gate arrays (FPGA's) for parallel data processing, camera technology, global navigation satellite systems (GNSS's) for navigation, and battery technology such as the high energy density of lithium polymer batteries. Despite the success of the technology to date, there remains development before UAV's should be flying alongside manned aircraft or over populated areas. One concern is that UAV electronics are not as safe, reliable or robust as manned-aircraft electronics because UAV's are not certified by the FAA. Another concern for UAV operation is with control algorithms and sensors, particularly in the estimation of the aircraft state, which is the position, velocity, and orientation of the aircraft. Some problems, such as numerical stability of a control algorithm or flight in windy and turbulent conditions have only been solved for certain conditions of wind, weather, or maneuvers. Outside those conditions, the actual orientation of a flying craft can mislead to the control system, and the control system may not be able to recover without a crash. When pilots fly manned aircraft in instrument meteorological conditions, or conditions of limited visibility of the ground, terrain, and obstacles, the pilot must fly in a manner which avoids abrupt maneuvers which could disturb accuracy of the aircraft's instruments. In a UAV without a pilot, there is a need to estimate the position and orientation of a UAV in an absolute manner unambiguous relative to the Earth. The position and orientation estimate must not depend on carefully controlled flight paths, but instead the estimate must be robust in the presence of UAV flight dynamics. This thesis describes the design, implementation, and evaluation of a hardware platform for GPS based orientation sensing research. In this work, we considered a receiver with three or four RF sections, each connected to an antenna in a triangular or tetrahedral pyramid constellation. Specific requirements for the receiver hardware and functionality were created. Circuitry was designed to meet the requirements using commercial off-the-shelf (COTS) radio frequency (RF) modules, a mid-sized microcontroller, an FPGA, and other supporting components. A printed circuit board (PCB) was designed, fabricated, assembled, and tested. A GPS baseband processor was designed and coded in Verilog hardware description language. The design was synthesized and loaded to the FPGA, and the microcontroller was programmed to track satellites. With the hardware platform implemented, live satellite signals were found and tracked, and experiments were performed to explore the validity of GPS based orientation sensing using short antenna baselines. The platform successfully allows the user to develop correlator designs and explore carrier phase based orientation measurement using only software/Verilog modifications. Initial results of carrier phase based orientation sensing are promising, but the presence of multipath signal interference shows room for improvement to the baseband processing code.

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