209398246
From Kansas to Oz.
45789414
A Simple and Unifying Approach to Subjective Objects
Abstract Most object-oriented languages are objective: an object always responds to the same message in the same way. Subjective objects more closely match naturally occurring systems, and they provide consistent solutions to a wide range of problems, problems that otherwise must be solved by varied and specialized mechanisms. Applying a perspective-receiver symmetry principle in designing the subjectivity semantics of an object-oriented language results in a semantically uncluttered language with a surprisingly wide range of utility. We employ this approach in creating the language Us, a subjective version of Self.
41296063
Prototype-based languages: object lessons from class-free programming
61043025
Auditory icons in large-scale collaborative environments
52856801
Subjectivity in object-oriented systems
5462210
Programming as an Experience: The Inspiration for Self
The Self system attempts to integrate intellectual and nonintellectual aspects of programming to create an overall experience. The language semantics, user interface, and implementation each help create this integrated experience. The language semantics embed the programmer in a uniform world of simple objects that can be modified without appealing to definitions of abstractions. In a similar way, the graphical interface puts the user into a uniform world of tangible objects that can be direcdy manipulated and changed without switching modes. The implementation strives to support the world-of-objects illusion by minimizing perceptible pauses and by providing true source-level semantics without sacrificing performance. As a side benefit, it encourages factoring. Although we see areas that fall short of the vision, on the whole, the language, interface, and implementation conspire so that die Self programmer lives and acts in a consistent and malleable world of objects.
17086760
Cost profile of a highly assured, secure operating system
The Logical Coprocessing Kernel (LOCK) began as a research project to stretch the state of the art in secure computing by trying to meet or even exceed the “A1” requirements of the Trusted Computer System Evaluation Criteria (TCSEC). Over the span os seven years, the project was transformed into an effort to develop and deploy a product: the Standard Mail Guard (SMG). Since the project took place under a US government contract, the development team needed to maintain detailed records of the time spent on the project. The records from 1987 to 1992 have been combined with information about software code size and error detection. This information has been used to examine the practical impacts of high assurance techniques on a large-scale software development program. Tasks are associated with the A1 formal assurance requirements added approximately 58% to the development cost of security-critical software. In exchange for these costs, the formal assurance tasks (formal specifications, proofs, and specification code correspondence) uncovered 68% of the security flaws detected in LOCK's critical security mechanisms. However, a study of flaw detection during the SMG program found that only 14% of all flaws detected were of the type that could be detected using formal assurance, and that the work of the formal assusrance team only accounted for 19% of all flaws detected. While formal assurance is clearly effective at detecting flaws, its practicality hinges on the degree to which the formally modeled system properties represent all of a system's esential properties.
12720907
XCS for robust automatic target recognition
A primary strength of the XCS approach is its ability to create maximally accurate general rules. In automatic target recognition (ATR) there is a need for robust performance beyond so-called standard operating conditions (SOCs, those conditions for which training data is available) to extended operating conditions (EOCs, conditions of known targets that cannot be foreseen and trained for). EOCs include things like vehicle-specific variations, environmental effects (mud, etc.), unanticipated viewing angles, and articulation of components of the target (hatches, turrets, etc.). This paper presents experiments where XCS addresses structural generalization over global and local features normally used in ATR classification. In many SOCs, these features are adequate for target recognition. Our goal with XCS is to form generalized rules that utilize these features for effective ATR in EOCs. Results show that XCS is effective in this generalization task. Conclusions and future directions for research are discussed.
33919116
The Fighter Aircraft LCS: A Case of Different LCS Goals and Techniques
A system employed by the authors to acquire novel fighter aircraft manoeuvres from combat simulation is more akin to the traditional LCS model than to more recent systems. Given the difficulties often experienced in LCS research on simple problems, one must ask how a relatively primitive LCS has had consistent success in the complex domain of fighter aircraft manoeuvring. This paper presents the fighter aircraft LCS, in greater detail than in previous publications. Positive results from the system are discussed. The paper then focuses on the primary reasons the fighter aircraft LCS has avoided the difficulties of the traditional LCS. The authors believe the system's success has three primary origins: differences in credit assignment, differences in action encoding, and (possibly most importantly) a difference in system goals. In the fighter aircraft system, the goal has been simply the discovery of innovative, novel tactics, rather than online control. The paper concludes by discussing the most salient features of the fighter aircraft learning system, and how those features may be profitably combined with other LCS developments.
11105386
Automated auditing of design principle adherence
Software design patterns and refactoring browsers are useful tools in developing high-quality software. Object-Oriented Oracle (OOO) is a tool that combines patterns and refactoring and extends them with the ability to recognize when the source-base doesn't adhere to software design principles. OOO relies on sophisticated compiler analyses and a set of heuristics to recognize characteristics of the code where a design principle is applicable, but is not being used. We present an example where the OOO can recognize noncompliance of design rules and the analyses and heuristics that are used to do the recognition. We also discuss other patterns where this approach applies and results from a prototype.
10260970
Pure adaptive search in global optimization
Pure adaptive seach iteratively constructs a sequence of interior points uniformly distributed within the corresponding sequence of nested improving regions of the feasible space. That is, at any iteration, the next point in the sequence is uniformly distributed over the region of feasible space containing all points that are strictly superior in value to the previous points in the sequence. The complexity of this algorithm is measured by the expected number of iterations required to achieve a given accuracy of solution. We show that for global mathematical programs satisfying the Lipschitz condition, its complexity increases at mostlinearly in the dimension of the problem.