http://lib.yhn.edu.vn/handle/YHN/66 Wed, 12 Aug 2026 11:14:06 GMT 2026-08-12T11:14:06Z http://lib.yhn.edu.vn/handle/YHN/12154 Nhan đề : test Sun, 01 Jan 2023 00:00:00 GMT https://ikr.inceif.org/image/item.png 2023-01-01T00:00:00Z http://lib.yhn.edu.vn/handle/YHN/741 Nhan đề : Best-first Enumeration Based on Bounding Conflicts, and its Application to Large-scale Hybrid Estimation Mô tả: With the rise of autonomous systems, there is a need for them to have high levels of robustness and safety. This robustness can be achieved through systems that are self-repairing. Underlying this is the ability to diagnose subtle failures. Likewise, online planners can generate novel responses to exceptional situations. These planners require an accurate estimate of state. Estimation methods based on hybrid discrete/continuous state models have emerged as a method of computing precise state estimates, which can be employed for either diagnosis or planning in hybrid domains. However, existing methods have difficulty scaling to systems with more than a handful of components. Discrete state estimation capabilities can scale to this level by combining best-first enumeration and conflict-directed search. Best-first methods have been developed for hybrid estimation, but the creation of conflict-directed methods has previously been elusive. While conflicts are used to learn from constraint violation, probabilistic hybrid estimation is relatively unconstrained. In this paper we present an approach to hybrid estimation that unifies best-first enumeration and conflict-directed search through the concept of "bounding" conflicts, an extension of conflicts that represent tighter bounds on the cost of regions of the search space. This paper presents a general best-first search and enumeration algorithm based on bounding conflicts (A*BC) and a hybrid estimation method based on this enumeration algorithm. Experiments show that an A*BC powered state estimator produces estimates faster than the current state of the art, particularly on large systems. https://ikr.inceif.org/image/item.png http://lib.yhn.edu.vn/handle/YHN/740 Nhan đề : Predicting Problems Caused by Component Upgrades Mô tả: This report presents a new, automatic technique to assess whether replacing a component of a softwaresystem by a purportedly compatible component may change the behavior of the system. The techniqueoperates before integrating the new component into the system or running system tests, permitting quickerand cheaper identification of problems. It takes into account the system s use of the component, becausea particular component upgrade may be desirable in one context but undesirable in another. No formalspecifications are required, permitting detection of problems due either to errors in the component or toerrors in the system. Both external and internal behaviors can be compared, enabling detection of problemsthat are not immediately reflected in the output.The technique generates an operational abstraction for the old component in the context of the system,and one for the new component in the context of its test suite. An operational abstraction is a set of programproperties that generalizes over observed run-time behavior. Modeling a system as divided into modules,and taking into account the control and data flow between the modules, we formulate a logical conditionto guarantee that the system s behavior is preserved across a component replacement. If automated logicalcomparison indicates that the new component does not make all the guarantees that the old one did, thenthe upgrade may affect system behavior and should not be performed without further scrutiny.We describe a practical implementation of the technique, incorporating enhancements to handle nonlocalstate, non-determinism, and missing test suites, and to distinguish old from new incompatibilities. Weevaluate the implementation in case studies using real-world systems, including the Linux C library and 48Unix programs. Our implementation identified real incompatibilities among versions of the C library thataffected some of the programs, and it approved the upgrades for other programs that were unaffected by thechanges.This report is a revision of the first author s Master s thesis, submitted January 2004. https://ikr.inceif.org/image/item.png http://lib.yhn.edu.vn/handle/YHN/739 Nhan đề : System Validation via Constraint Modeling Mô tả: Constraint modeling could be a very important system validation method, because its abilities are complementary to both testing and code inspection. In particular, even though the ability of constraint modeling to find errors is limited by the simplifications which are introduced when making a constraint model, constraint modeling can locate important classes of errors which are caused by non-local faults (i.e., are hard to find with code inspection) and manifest themselves as failures only in unusual situations (i.e., are hard to find with testing). https://ikr.inceif.org/image/item.png