The motion planning problem can be formulated as a Markov decision process (MDP), if the uncertainties in the robot motion and environments can be modeled probabilistically. The complexity of solving these MDPs grow exponentially as the dimension of the problem increases and hence, it is nearly impossible to solve the problem even without constraints. Using hierarchical methods, these MDPs can be transformed into a semi-Markov decision process (SMDP) which only needs to be solved at certain landmark states. In the deterministic robotics motion planning community, sampling based algorithms like probabilistic roadmaps (PRM) and rapidly exploring random trees (RRTs) have been successful in solving very high dimensional deterministic problem. However they are not robust to system with uncertainties in the system dynamics and hence, one of the primary objective of this work is to generalize PRM/RRT to solve motion planning with uncertainty. We first present generalizations of randomized sampling based algorithms PRM and RRT, to incorporate the process uncertainty, and obstacle location uncertainty, termed as "generalized PRM" (GPRM) and "generalized RRT" (GRRT). The controllers used at the lower level of these planners are feedback controllers which ensure convergence of trajectories while mitigating the effects of process uncertainty. The results indicate that the algorithms solve the motion planning problem for a single agent in continuous state/control spaces in the presence of process uncertainty, and constraints such as obstacles and other state/input constraints. Secondly, a novel adaptive sampling technique, termed as "adaptive GPRM" (AGPRM), is proposed for these generalized planners to increase the efficiency and overall success probability of these planners. It was implemented on high-dimensional robot n-link manipulators, with up to 8 links, i.e. in a 16-dimensional state-space. The results demonstrate the ability of the proposed algorithm to handle the motion planning problem for highly non-linear systems in very high-dimensional state space. Finally, a solution methodology, termed the "multi-agent AGPRM" (MAGPRM), is proposed to solve the multi-agent motion planning problem under uncertainty. The technique uses a existing solution technique to the multiple traveling salesman problem (MTSP) in conjunction with GPRM. For real-time implementation, an ?inter-agent collision detection and avoidance? module was designed which ensures that no two agents collide at any time-step. Algorithm was tested on teams of homogeneous and heterogeneous agents in cluttered obstacle space and the algorithm demonstrate the ability to handle such problems in continuous state/control spaces in presence of process uncertainty.

Error-control codes, which are being extensively used in communication systems, have found themselves very useful in data storage as well during the past decade. This thesis deals with two types of codes for data storage, one pertaining to the issue of privacy and the other to reliability. In many scenarios, user accessing some critical data from a server would not want the server to learn the identity of data retrieved. This problem, called Private Information Retrieval (PIR) was rst formally introduced by Chor et al and they gave protocols for PIR in the case where multiple copies of the same data is stored in non-communicating servers. The PIR protocols that came up later also followed this replication model. The problem with data replication is the high storage overhead involved, which will lead to large storage costs. Later, Fazeli, Vardy and Yaakobi, came up with the notion of PIR code that enables information-theoretic PIR with low storage overhead. In the rst part of this thesis, construction of PIR codes for certain parameter values is presented. These constructions are based on a variant of conventional Reed-Muller (RM) codes called binary Projective Reed-Muller (PRM) codes. A lower bound on block length of systematic PIR codes is derived and the PRM based PIR codes are shown to be optimal with respect to this bound in some special cases. The codes constructed here have smaller block lengths than the short block length PIR codes known in the literature. The generalized Hamming weights of binary PRM codes are also studied. Another work described here is the implementation and evaluation of an erasure code called Coupled Layer (CL) code in Ceph distributed storage system. Erasure codes are used in distributed storage to ensure reliability. An additional desirable feature required for codes used in this setting is the ability to handle node repair efficiently. The Minimum Storage Regenerating (MSR) version of CL code downloads optimal amount of data from other nodes during repair of a failed node and even disk reads during this process is optimum, for that storage overhead. The CL-Near-MSR code, which is a variant of CL-MSR, can efficiently handle a restricted set of multiple node failures also. Four example CL codes were evaluated using a 26 node Amazon cluster and performance metrics like network bandwidth, disk read and repair time were measured. Repair time reduction of the order of 3 was observed for one of those codes, in comparison with Reed Solomon code having same parameters. To the best of our knowledge, such large gains in repair performance have never been demonstrated before.

Effective Governance of Enterprise Information Technology (GEIT) is very important for an enterprise that has a huge investment in IT infrastructure. Implementing effective GEIT helps an enterprise to meet stakeholder needs by creating business value through strategic business-IT alignment. This study focuses on the analysis of GEIT implementation related to strategic business-IT alignment using Control Objectives for Information and Related Technology (COBIT 5), using the Commercial Bank of Ethiopia (CBE) as a case study. Strategic alignment is found to be the main concern of GEIT and strong alignment between business objectives and IT capabilities as a means of creating an effective foundation for business execution. There are various internationally accepted GEIT good practices and standards. In this study, COBIT 5 is selected for its strong aspects of control objectives for strategic business-IT alignment that help enterprises’ security, risk and compliance guidance and serves as a tool for leveraging GEIT. COBIT 5 is the leading business framework for the GEIT by making clear that there is a separation between governance and management of IT. This is a single integrated framework that covers the enterprise holistically and integrates with other important frameworks and standards at an advanced level. In addition to this, the use of COBIT 5 Balanced Score Card (BSC) for performance measurement tool (goals cascade), Process Reference Model (PRM), Process Assessment Model (PAM), principles and enablers and Capability Maturity Model (CMM) tool also utilise IT investments more effectively and accurately and measure performance with lower costs through stronger governance. This study analysed how enterprises effectively implement GEIT practices using COBIT 5 to achieve strong strategic business-IT alignment. The target groups of the study were the top management and IT management of CBE. The researcher used explanatory sequential mixed methods (both quantitative and qualitative) data collection techniques and analysis procedures. In the quantitative data collection, data were collected and analysed using GEIT practices maturity assessment tool, Luftman Strategic Alignment Maturity Model (LAMM) tool and the data analysed using Statistical Package for the Social Science (SPSS). In the qualitative phase of the study, evidence was collected and examined from observation and participation, document review, focus group, formal and informal discussions with selected managements of CBE and gap assessment using COBIT 5. Finally, the researcher integrated results to combine the quantitative and qualitative methods. The finidngs of the quantitative analysis indicate that the maturity level of GEIT practices implementation was 1.77, around level 2 maturity level (repeatable but intuitive), whereas the business-IT alignment maturity level of 53.13% agrees that strategic alignment business-IT was good level 3 (established, focused processes) in the case of CBE. GEIT practices implementation regarding strategic business-IT alignment is found to be positive. The data qualitative analysis indicates that the achievement of the capability level of GEIT processes is not defined and deployed based on international best practices and also confirms that the GEIT BSC is not yet implemented. The achievement capability level of GEIT processes implementation using COBIT 5 is under level 2. In this study, the gap between the existing GEIT practices processes and desirable level 4 (managed and measurable) using COBIT 5 was identified and a method to fill the gap was proposed. / School of Computing / M. Sc. (Computing)