Sheela Ramanna

Sensor fusion: a rough granular approach

The paper introduces an application of a particular form of rough granular computing in fusing (combining) sensor readings. The intent of the paper is to describe a system that engages in a form of knowledge discovery based on sensor fusion. Such a system responds to sensor outputs in a manner that is selective, determines the relevance of each sensor in a classification effort, and constructs information granules computationally useful in arriving at a decision (proposed solution to a problem) in a problem-solving system. A sensor is a device that responds to each stimulus by converting its measured input to some form of usable output. Relevance of a sensor is computed with a rough integral that computes a form of ordered weighted average of sensor values. The construction of an information granule depends on the selection of a threshold for sensor values. Only those sensors with rough integral values approaching a selected threshold are fused (i.e., used to construct a granule). The contribution of the paper is the introduction of a sensor fusion method based on rough integration. By way of practical application, an approach to fusion of homogeneous sensors deemed relevant in a classification effort is considered.

Designing a dynamic integrity constraint checker with nonmonotonic logic

The authors report on the design of a dynamic integrity constraint checker with a nonmonotonic interval logic (IL). Central to this logic is the inclusion of the unless operator which captures the nonmonotonicity of dynamic integrity constraints over temporal intervals. IL is embedded in the Ada/ISL Interval Specification Language which has been utilized in the design of the Icarus Integrity System. In this system, the answer to a query depends on the availability of an explicit body of knowledge (knowledge base) about the integrity of data items contained in the query. The principal inference mechanism in this system is the refutation of faulty beliefs about data based on partial information and intuition, with respect to facts in the knowledge base. A technique for the verification of the Icarus kernel is presented. A family of assertions about the completeness, correctness, and confidence integrity characteristics about data is included in the integrity model.<<ETX>>

Temporal specification of an integrity kernel for multimedia office systems

The authors report on the temporal specification of integrity systems with the interval specification language ISL. ISL is based on a form of interval temporal logic and provides a framework for a logic of knowledge and belief about data integrity. ISL is a design tool for integrity kernels in office information systems where the dynamic evaluation of data integrity based upon partial knowledge and informed judgment is required. The D.D. Clark and D.R.A. Wilson (1981) integrity model, designed to prevent fraudulent and erroneous data modification, is subsumed. An integrity system which includes extensions to the concept defined in the Multimedia Office Server (MULTOS) project is given. An integrity characteristic tuple incorporating the notions of correctness, completeness, quality, timeliness, and confidence associated with each constrained document component is presented. A specification for a simplified integrity kernel is provided.<<ETX>>

CONDUCTOR: a model for reliable interprocess communication

The authors introduce a model for reliable interprocess communication based on an extension of the gentleman administrator model. The architecture of the CONDUCTOR model provides increased concurrency and a simplified user view of a distributed system. The increased concurrency stems from the potential for multiple instances of administrators to coexist within administrator groups. Users communicate directly with a conductor process instead of a variety of administrators. The new model provides an abstraction which hides administrators needed to service user requests. This form of multiprocess structuring is in keeping with the philosophy of the original Thoth system. A basis for reliable communication between administrator groups and the conductor process is presented. Reliable communication in this model is provided by enforcing atomicity of message delivery and ordering of messages. The architecture of the CONDUCTOR model is robust inasmuch as it is process failure tolerant. A mechanism for detecting and replacing failed administrators of a failed conductor using N. Natarjans (1988) watchdog processes is presented.<<ETX>>

Logic of knowledge and belief in the design of an integrity kernel for an office information system (abstract)

An integrity specification language (ISL) based upon a form of interval temporal logic is defined and the framework for a logic of knowledge and beliefs about data integrity is developed. The intended purpose of ISL is for the design of integrity kernels in an office information system in which the dynamic evaluation of data integrity based upon partial knowledge and informed judgement relative to update request by clients, is required. ISL itself is described in an earlier paper and summarized in this paper. Beliefs in ISL are specified with a form of interval temporal logic and provide an extension of the Moser technique for formulating beliefs. The Clark and Wilson model designed to prevent fraudulent and erroneous data modification is subsumed. An integrity Characteristic Tuple (ICT) incorporates the notions of correctness, completeness, quality, timeliness and confidence is associated with each Constrained Data Item (CDI). An integrity system which includes extensions of the concept and function of the server architecture as defined in the Multimedia Office Server (MULTOS) project, is given. An integrity kernel is defined which incorporates an algorithm for the detection of faults in presumptions about data integrity based upon knowledge and beliefs. A simplified integrity kernel is specified formally and a corresponding sample server-client session is provided.