Lawrence Robinson

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A method for describing and structuring programs that simplifies proofs of their correctness is presented. The method formally represents a program in terms of levels of abstraction, each level of which can be described by a self-contained nonprocedural specification. The proofs, like the programs, are structured by levels. Although only manual proofs are(More)
Two nearly equivalent models of multilevel security are presented. The use of multiple models permits the utilization of each model for purposes where that model is particularly advantageous. In this case, the more general model is simple and easily comprehensible, being more abstract, and is useful for exposition of the meaning of multilevel security. The(More)
Hierarchical programming is being increasingly recognized as helpful in the construction of large programs. Users of hierarchical techniques claim or predict substantial increases in productivity and in the reliability of the programs produced. In this paper we describe a formal method for hierarchical program specification, implementation, and proof. We(More)
This paper summarizes current research at RI aimed at developing secure operating systems and verifying certain critical properties of these systems. It is seen that proofs of design properties can be relatively straightforward when the design is specified in suitable formal specification language. These proofs demonstrate the correspondence between the(More)
Abductor, adductor, and combined reinnervation procedures have been explored with variable success rates. We describe the experience of a tertiary care center with adductor reinnervation procedures, including preoperative and postoperative videostroboscopy and electromyography (EMG) findings. A retrospective chart review was performed from 1997 to 2001 that(More)
BACKGROUND Glucocorticoid replacement is commonly required to treat secondary adrenal insufficiency after surgical resection of unilateral cortisol-secreting adrenocortical adenomas. Here, we describe a patient with unilateral cortisol-secreting adenomas in which the preoperative use of mifepristone therapy was associated with recovery of the(More)
Tremor laryngeal dystonia is a clinical entity distinct from adductor laryngeal dystonia, according to perceptual, stroboscopic, and fine-wire electromyographic findings. Treatment with botulinum toxin has proven more difficult for tremor laryngeal dystonia than for adductor laryngeal dystonia, yet no treatment variations have been considered that might(More)
Although perceptual and stroboscopic data help in diagnosing and classifying laryngeal dystonia, these measures do not aid the voice clinician in targeting which specific muscles to treat with botulinum toxin. Most patients achieve smoother, less effortful voicing with standard injection regimens. However, there is a notable failure rate. We performed(More)