Mitre Corporation

About: Mitre Corporation is a company organization based out in Bedford, Massachusetts, United States. It is known for research contribution in the topics: Air traffic control & National Airspace System. The organization has 4884 authors who have published 6053 publications receiving 124808 citations. The organization is also known as: Mitre & MITRE.

Random access protocol for multi-media networks

Abstract: A protocol for mixed voice and data access to a synchronous broadcast communications channel (116) is provided. Transmission on the broadcast communications channel (116) is by means of a plurality of time division frames, each such frame being defined by a plurality of time slots (210). The protocol requires that a user determine whether a time slot is available. If a slot is available, a user transmits a preamble (212) on the broadcast communications channel and then substantially simultaneously monitors the channel for determining whether a collision of the preamble has occurred. If a collision has occurred with a second user who has a higher priority, the first user reattempts to acquire an available time slot after a time delay, the time delay being equivalent to a random number of time slots. If on the other hand, the collision was with a second user of equal priority, both users will reattempt acquisition of available time slots after respective random time delays. The preambles of users of different priority are transmitted using a non-interfering code or modulation frequency, thereby allowing the higher priority user to continue transmission of the remaining fields which make up that user's information packet. Another key feature of the protocol is the use of the preamble (212) to identify voice users that are in silence periods, transmitting no data. Under these circumstances, the protocol permits data users to utilize such identified time slots when they are encountered, thereby increasing the throughput of the data communications system.

The representation of multimodal user interface dialogues using discourse pegs

Abstract: The three-tiered discourse representation defined in (Luperfoy, 1991) is applied to multimodal human-computer interface (HCI) dialogues. In the applied system the three tiers are (1) a linguistic analysis (morphological, syntactic, sentential semantic) of input and output communicative events including keyboard-entered command language atoms, NL strings, mouse clicks, output text strings, and output graphical events; (2) a discourse model representation containing one discourse object, called a peg, for each construct (each guise of an individual) under discussion; and (3) the knowledge base (KB) representation of the computer agent's 'belief' system which is used to support its interpretation procedures. I present evidence to justify the added complexity of this three-tiered system over standard two-tiered representations, based on (A) cognitive processes that must be supported for any non-idealized dialogue environment (e.g., the agents can discuss constructs not present in their current belief systems), including information decay, and the need for a distinction between understanding a discourse and believing the information content of a discourse; (B) linguistic phenomena, in particular, context-dependent NPs, which can be partially or totally anaphoric; and (C) observed requirements of three implemented HCI dialogue systems that have employed this three-tiered discourse representation.

Trusted products evaluation

Abstract: computer and communications technologies and trends toward standardization , interoperability, and connectivity pose a growing security threat to Automatic Data Processing (ADP) and te][ecommunications systems that process sensitive or classified information. The activation of a threat could result in: disclosure, modification, or destruction of' sensitive or classified information; modification to hardware or software; and/or nonavailability of the system services. ~F\" / / // / ,/ / /

Task-structured probabilistic I/O automata

Abstract: Modeling frameworks such as probabilistic I/O automata (PIOA) and Markov decision processes permit both probabilistic and nondeterministic choices. In order to use such frameworks to express claims about probabilities of events, one needs mechanisms for resolving the nondeterministic choices. For PIOAs, nondeterministic choices have traditionally been resolved by schedulers that have perfect information about the past execution. However, such schedulers are too powerful for certain settings, such as cryptographic protocol analysis, where information must sometimes be hidden. Here, we propose a new, less powerful nondeterminism-resolution mechanism for PIOAs, consisting of tasks and local schedulers. Tasks are equivalence classes of system actions that are scheduled by oblivious, global task sequences. Local schedulers resolve nondeterminism within system components, based on local information only. The resulting task-PIOA framework yields simple notions of external behavior and implementation, and supports simple compositionality results. We also define a new kind of simulation relation, and show it to be sound for proving implementation. We illustrate the potential of the task-PIOA framework by outlining its use in verifying an oblivious transfer protocol.