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Electronic devices are widely used in today’s hospitals and the possibilities they offer are increasing every day. The devices are often embedded systems, running outdated operating systems and need to have a high uptime which makes them vulnerable to malicious software (malware). This thesis examines the ways malware can propagate through the Universal Serial Bus (USB) with the help of social engineering. Valuable assets are defined and different threat scenarios to these assets are presented. Lastly, the different scenarios are evaluated based on which assets they impact and how to effective mitigate the threats they present. Short- and long-term mitigations are presented to secure the devices in a broader view.

Optimization problems constrained by partial differential equations (PDEs) arise in a variety of fields when one wants to optimize a system governed by a PDE. The goal is to compute a control variable such that a state variable is as close as possible to some desired state when control and state are coupled by some PDE. The control and state may have additional conditions acting on them, such as, the so-called box constraints which define upper and lower bounds on these variables. Here we study the optimal control of the Poison equation with pointwise inequality constraints on the state variable with Moreau-Yosida regularization. The state constraints make the optimality system nonlinear and a primal-dual active set method is used to solve it. In each nonlinear step a large saddle point system has to be solved. This system is generally ill-conditioned and preconditioning is required to efficiently solve the system with an iterative solution method. The preconditioner should also be efficiently realizable. The convergence rate is also dependent on model and discretization parameters, for this reason, a preconditioning technique needs to be applicable to a wide range of parameters. Three preconditioners are tested for the problem and compared in terms of iteration counts and execution time for wide range of problem and discretization parameters.

Software Defined Networking is a technology that introduces modular and programmable networks that uses separated control- and data-planes. Traditional networks use mostly proprietary protocols and devices that needs to communicate with each other and share information about routes and paths in the network. SDN on the other hand uses a controller that communicates with devices through an open source protocol called OpenFlow. The routing rules of flows can be inserted into the networking devices by the controller. This technology is still new and it requires more research to provide evidence that it can perform better, or at least as good as, the conventional networks. By doing some experiments on different topologies, this thesis aims at discovering how delays of flows are affected by having OpenFlow in the network, and identifying overhead of using such technology. The results show that, the overhead can be to large for time and noise sensitive applications and average delay is comparable to conventional networks.

Geographical information system with remotely sensed data can be instrumental in many ways for disaster management and post disaster rehabilitation. During last few decades the usage of remotely sensed data has extensively increased, although image interpretation tools are not highly accurate but still considered as fast, reliable and useful way to get information from imagery. Disaster assessment, management and rehabilitation are always creates challenge for experts. Population growth, expansion in settlements either in the rural or in the urban areas bring more problems not only for the humans but it also affect the global environment Such global changes on the massive scale disturbs the ecological processes. GIS along with Remote sensing data can change the whole scenario in very short period of time. All the departments concerning to strategic disaster planning process can share their information by using the single platform, so for this purpose spatial database can be helpful by providing the spatial data in digital format to the department concerned. Spatial phenomena can be observed by using different image analysis techniques and the resultant thematic map display the spatial variations and changes that describe the particular phenomenon whether it was any disaster or change in soil type or vegetation type. Remotely sensed data like aerial, satellite and radar images are very useful for disaster management strategy formulation process. Integration of GIS and remote sensing proved itself the best especially for land-use, land-cover mapping. For this purpose pixel based, sub-pixel based, pre-field and object oriented classification approach are being in use around the world. But thematic maps created from image analyzed by using object oriented classifiers contain more accuracy than any other techniques.

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Abstract Over the years, the opposition parties argued that the existing election system in Ethiopia has many problems during the election process and the outcome of actual results and it is not a kind of election system they can trust.  Whereas the government officials claimed it was fair and free election system. The integrity of the election process is fundamental to the integrity of democracy itself. Hence, electronic voting (e-Voting) is a newly popular method to cast ballots of an election using electronic devices. This scheme is deployed highly as a main election system in some countries and still others are using a hybrid system. However, there are countries like Ethiopia which adopt the manual election scheme for several years till now. Therefore, the purpose of this study is to understand the perception of the government and opposition political parties towards the prospect of implementing e-voting scheme in the present context of Ethiopia.   Even though there are setbacks in implementing e-voting in the present political situation of Ethiopia. However, the benefits are deemed to be much useful. Therefore, it is in the hands of the public and the government to work in developing and adopting e-voting scheme in a way that is helpful for both stakeholders. This paper suggests the government and the oppositions should have a reasonable consensus and planned date for starting the campaign which gives the right for the people for free and fair election and the rise of new political arena.   Key words- e-voting, hybrid system, manual election scheme

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