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Software components are meant to be reusable and flexible by design. These characteristics and others continue attracting software developers to adapt a component (typically designed elsewhere) into their systems. However, software components are also vulnerable to reliability and security problems due to existence of non-obvious faults. We believe that a systematic approach to detect failures of a component and prioritize components using such failures can help developers decide on appropriate solutions to improve reliability. In this thesis, we present a framework that can help developers in detecting and ranking component failures systematically so that more reliable software can be achieved. Our proposed framework can allow monitoring critical components within a system under instrumentation, detecting failures based on specifications and using failure data and input from developers to rank the components. The proposed approach provides information for developers who could decide if the reliability could be improved by trivial code modification or require advanced reliability techniques. A prototype is designed along with a number of failure scenarios to detect specific failure types within a component. Four major failure types (value, timing, commission, and omission) are detected and used to rank software components. We conducted an experimental evaluation using two subject systems to assess the effectiveness of the proposed framework and to measure its performance overhead. Our experimental results show that the approach can benefit system developers by prioritizing components for effective maintenance with a minimal overhead. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2013-09-09 23:08:02.035

Lu Guowei. / "January 2005." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

A comprehensive framework has been developed for designing a GSN. The focus of this thesis is the capacity planning problem which finds the edge capacities for a given physical topology with specifications of the I/O constraints at the nodes. Two kinds of GSN are studied: (1) For the design of a Wide-Sense Non-Blocking GSN (WSNB-GSN), a rigorous mathematical framework is presented. Duality transformation technique that transforms the initial, infinite and infeasible mathematical formulation into a finite feasible formulation is shown. A procedure for finding the realizable lower bound of the cost of a WSNB-GSN is presented and two different solution approaches are proposed. (2) For the design of a Rearrangeably Non-Blocking GSN (RNB-GSN), a straightforward mathematical formulation is presented first. A procedure using the cut condition to find the lower bound of the cost of a RNB-GSN with a general topology is shown then. The optimal solution in the design of a RNB-GSN with an unlimited-size ring topology is demonstrated with a theorem. / Dynamic bandwidth provisioning and full survivability against link failures are two of the most important requirements for future optical networks. Since previous methodologies could not deal with these two issues simultaneously, a new survivable network concept called the "Generalized Survivable Network" (GSN) is proposed. Generalized Survivable Network incorporates the non-blocking network concept into the survivable network design. Here, "generalized" means the generalization of a network from satisfying a single demand matrix to satisfying the set of all allowable demand matrices under the Input and Output (I/O) access capacity constraints at the network nodes. / Numerical experiments have been carried out to verify the performance of GSN. It is demonstrated that the deploying cost of a WSNB-GSN is within a factor of 2 compared with that of a random sample of a single-period survivable network. The cost of building a RNB-GSN with a ring topology is shown to be about 14% to 45% less than that of building a WSNB-GSN. The framework for planning a GSN is applicable to network planning for future optical networks and survivable IP networks. / Ho Kwok-shing. / "September 2006." / Adviser: Cheung Kwok Wai. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1823. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 118-124). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Internet computing enables the construction of large-scale and complex applications by aggregating and sharing computational, data and other resources across institutional boundaries. The agent model can address the ever-increasing challenges of scalability and complexity, driven by the prevalence of Internet computing, by its intrinsic properties of autonomy and reactivity, which support the flexible management of application execution in distributed, open, and dynamic environments. However, the non-deterministic behaviour of autonomous agents leads to a lack of control, which complicates exception management in the system, thus threatening the robustness and reliability of the system, because improperly handled exceptions may cause unexpected system failure and crashes. / In this dissertation, we investigate and develop mechanisms to integrate intrinsic support for concurrency control, exception handling, recoverability, and robustness into multi-agent systems. The research covers agent specification, planning and scheduling, execution, and overall coordination, in order to reduce the impact of environmental uncertainty. Simulation results confirm that our model can improve the robustness and performance of the system, while relieving developers from dealing with the low level complexity of exception handling. / A survey, along with a taxonomy, of existing proposals and approaches for building robust multi-agent systems is provided first. In addition, the merits and limitations of each category are highlighted. / Next, we introduce the ARTS (Agent-Oriented Robust Transactional System) platform which allows agent developers to compose recursively-defined, atomically-handled tasks to specify scoped and hierarchically-organized exception-handling plans for a given goal. ARTS then supports automatic selection, execution, and monitoring of appropriate plans in a systematic way, for both normal and recovery executions. Moreover, we propose multiple-step backtracking, which extends the existing step-by-step plan reversal, to serve as the default exception handling and recovery mechanism in ARTS. This mechanism utilizes previous planning results in determining the response to a failure, and allows a substitutable path to start, prior to, or in parallel with, the compensation process, thus allowing an agent to achieve its goals more directly and efficiently. ARTS helps developers to focus on high-level business logic and relaxes them from considering low-level complexity of exception management. / One of the reasons for the occurrence of exceptions in a multi-agent system is that agents are unable to adhere to their commitments. We propose two scheduling algorithms for minimising such exceptions when commitments are unreliable. The first scheduling algorithm is trust-based scheduling, which incorporates the concept of trust, that is, the probability that an agent will comply with its commitments, along with the constraints of system budget and deadline, to improve the predictability and stability of the schedule. Trust-based scheduling supports the runtime adaptation and evolvement of the schedule by interleaving the processes of evaluation, scheduling, execution, and monitoring in the life cycle of a plan. The second scheduling algorithm is commitment-based scheduling, which focuses on the interaction and coordination protocol among agents, and augments agents with the ability to reason about and manipulate their commitments. Commitment-based scheduling supports the refactoring and parallel execution of commitments to maximize the system's overall robustness and performance. While the first scheduling algorithm needs to be performed by a central coordinator, the second algorithm is designed to be distributed and embedded into the individual agent. / Finally, we discuss the integration of our approaches into Internet-based applications, to build flexible but robust systems. Specifically, we discuss the designs of an adaptive business process management system and of robust scientific workflow scheduling.

Thesis (M.S.)--Ohio University, June, 2007. / Title from PDF t.p. Includes bibliographical references.

Cover title, 1975/76- : Data network reliability; annual report. Principal investigator, 1975/76- : J.M. Wozencraft. Report year ends June 30. Vols. for 1975/76- report on research supported by Information Processing Technology Office, Defense Advanced Research Projects Agency, U.S. Dept. of Defense, ARPA order no. 3045.5-7-75, program code no. 5T10, ONR/N00014-75-C-1183, ONR contract no. 049-383.

Electrical reliability assurance is a very important aspect of electrical power systems; significant consideration should be given to reliability at both the planning and operation stage of power systems. A decrease in reliability levels can lead to enormous economic losses, especially for certain industrial facilities, and utilities could be penalized for violation of the mandatory reliability standards. Besides the traditional methods for electrical reliability enhancement, it is highly recommended to consider the adoption of innovative technologies, such as the integration of Distributed Generation (DG) units into the electrical network, especially those which are based on renewable energy source (wind and photovoltaic). Distributed Generation technologies can be beneficial to the electrical distribution system performance. However, these pose certain technical challenges to the reliable operation of the system. In this work, we also focus on the micro-grid operation security during islanding mode of operation in the presence of DG units. In this thesis, the unique aspects of reliability evaluation for an electrical distribution system has been performed using system-independent analytical expressions, considering probabilistic load and DG unit modeling, under different scenarios including dispatchable and renewable DG units with reasonable penetration levels. Further, a modified adequacy formulation has been adopted during the islanding mode of operation in order to consider micro-grid load correlation and an additional load curtailment level introduced in this work. The extra curtailment is needed to ensure adequate technical constraints and allow successful micro-grid operation, when the dispatchable DG units rating in a micro-grid is less than a defined percentage of the micro-grid peak load at time of islanding. Afterwards, during islanding, a second load curtailment level is adopted as needed to ensure service continuity under different operational conditions. A distribution test system is considered, and accordingly reliability indices are evaluated for both the worst case load scenario (islanding occurs at peak load), and for a realistic case (islanding might occur at any load level). Further, Expected Energy Not Served is evaluated. In conclusion, the impacts of DG units and islanded operation of micro-grids have been analyzed for the enhancement of the overall reliability of the distribution system and the successful islanding mode of operational conditions.

Bulk electric system reliability assessment is an important activity in both vertically integrated and unbundled electric power utilities. The conventional deterministic N-1 criterion normally used in bulk electric system planning does not respond to the probabilistic factors that influence the reliability of the system and is a rigid criterion. New assessment procedures are therefore required that combine the traditional deterministic approach with probabilistic perspectives to provide a responsive planning criterion.<p>This research work introduces the concept of a joint deterministic-probabilistic (D-P) criterion for bulk electric system planning using a previously developed software package designated as MECORE. The D-P concept presented is a deterministic framework that incorporates a probabilistic criterion. This research examines the application of the conventional deterministic N-1, the basic probabilistic and the D-P criteria to two test systems. The studies show that the D-P approach is driven by the accepted deterministic N-1 criterion and influenced by the probabilistic criterion (Pc). The D-P technique adds additional probabilistic risk information to the traditional deterministic N-1 criterion that is useful when making system reinforcement decisions. <p>The research work illustrated in this thesis indicates that the D-P criterion and associated procedures for bulk electric system analysis can be effectively utilized in bulk electric system reliability assessment. The conclusions and the techniques presented in this thesis should prove valuable to those responsible for composite generation and transmission system expansion planning.

Microelectronic wire bonding is a manufacturing process used to electrically connect integrated circuits with circuit boards or other substrates. Conventionally, balls are molten at the end of a Au bonding wire and subsequently bonded on Al metallization of a integrated circuit. However, Pd/Ni metallization has recently been used for its improved mechanical properties. The bondability, bonding mechanism, and reliability of Au ball bonds on Pd are studied in this thesis. The substrates were produced in this project using three different materials. The base material is polished Cu in the shape of a coupon (1.0 cm × 1.0 cm × 0.5 mm). Cu coupons are plated with Ni (1.0 μm) using an electroless process, followed by electrolytic plating of a layer of Pd (0.3 μm), resulting in an arithmetic mean roughness of the surface of 0.08 μm (baseline sample, sample 0). Higher roughness values of 0.2, 0.4, and 0.5 μm are artificially produced by rolling (sample 1), sanding (sample 2), and sandblasting (sample 3), respectively, on the Cu surface before plating Ni and Pd. A 25 μm diameter Au wire is used for bonding on the polished and roughened substrates with a process temperature of T = 220 °C, and it was found that ≈ 4 % to ≈ 18 % less ultrasonic amplitude was required for successful bonding on the roughened substrates compared to the polished substrate. Bondability is measured by shear testing the ball bonds. An average ball bond strength achieved on the polished substrate is 130 MPa. This value is lower on the roughened substrate with the exception of the sandblasted substrate. Long-term thermal aging at 250 °C was performed with ball bonds on samples 0-3 for durations of ≈ 300 h. The reliability of the bonds is characterized by non-destructive contact resistance analysis during aging and destructive cross section analysis after aging. Contact resistance values for the ball bonds range from 1.6 to 3.5 mΩ at 20 °C before aging, and does not correlate with roughness. For the baseline sample, contact resistance of the ball bonds decreases during aging by -6 % (median value), which indicates electrical integrity of the interconnections at high temperature. This decrease possibly is due to interfacial gap filling by Au or Pd diffusion. In contrast, the contact resistance increases for the roughened samples 1-3 and changes are 0.4, 5, and 14 %, respectively (median values). A conclusive explanation for this increase has not yet been found. After 250 h of aging, a TEM analysis showed Au to Pd diffusion in the baseline sample with a diffusion depth of ≈ 0.1 μm Au. No intermetallics, voids, or contamination is found on the interfaces after aging according to nanohardness, SEM, and TEM analyses. No bond lift-offs or electrical opens were found for the aging temperature and durations chosen. No conclusive evidence for the presence of Au-Pd intermetallics or voids is found.