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Faculty Publications

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Articles 271 - 300 of 321

Full-Text Articles in Computer Engineering

On Localized Control In Qos Routing, Srihari Nelakuditi, Srivatsan Varadarajan, Zhi-Li Zhang Jun 2002

On Localized Control In Qos Routing, Srihari Nelakuditi, Srivatsan Varadarajan, Zhi-Li Zhang

Faculty Publications

In this note, we study several issues in the design of localized quality-of-service (QoS) routing schemes that make routing decisions based on locally collected QoS state information (i.e., there is no network-wide information exchange among routers). In particular, we investigate the granularity of local QoS state information and its impact on the design of localized QoS routing schemes from a theoretical perspective. We develop two theoretical models for studying localized proportional routing: one using the link-level information and the other using path-level information. We compare the performance of these localized proportional routing models with that of a global optimal proportional …

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A Localized Adaptive Proportioning Approach To Qos Routing, Srihari Nelakuditi, Zhi-Li Zhang Jun 2002

A Localized Adaptive Proportioning Approach To Qos Routing, Srihari Nelakuditi, Zhi-Li Zhang

Faculty Publications

In QoS routing, paths for flows are selected based on knowledge of resource availability at network nodes and the QoS requirements of flows. Several QoS routing schemes have been proposed that differ in the way they gather information about the network state and select paths based on this information. We broadly categorize these schemes into best path routing and proportional routing. The best path routing schemes gather global network state information and always select the best path for an incoming I-low,based on this global view. It has been shown that best path routing schemes require frequent exchange of network state, …

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Trusted Autonomy, Michael N. Huhns, Duncan A. Buell Jan 2002

Trusted Autonomy, Michael N. Huhns, Duncan A. Buell

Faculty Publications

We describe how agents are the right building blocks for constructing trustworthy systems. Robust software and trusted autonomy represent the future for agent technology and software engineering.

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Weaving A Computing Fabric, Michael N. Huhns, Larry M. Stevens, John W. Keele, Jim E. Wray, Warren M. Snelling, Greg P. Harhay, Randy R. Bradley Jan 2002

Weaving A Computing Fabric, Michael N. Huhns, Larry M. Stevens, John W. Keele, Jim E. Wray, Warren M. Snelling, Greg P. Harhay, Randy R. Bradley

Faculty Publications

As sources of information relevant to a particular domain proliferate, we need a methodology for locating, aggregating, relating, fusing, reconciling, and presenting information to users. Interoperability thus must occur not only among the information, but also among the different software applications that process it. Given the large number of potential sources and applications, interoperability becomes an extremely large problem for which manual solutions are impractical. A combination of software agents and ontologies can supply the necessary methodology for interoperability.

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Agents As Web Services, Michael N. Huhns Jan 2002

Agents As Web Services, Michael N. Huhns

Faculty Publications

Web services are extremely flexible. Most advantageously, a developer of Web services need not know who or what will use the services being provided. The paper discusses current standards for Web services, directory services and the Semantic Web. It considers how agents extend Web services in several important ways.

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Robust Software, Michael N. Huhns, Vance T. Holderfield Jan 2002

Robust Software, Michael N. Huhns, Vance T. Holderfield

Faculty Publications

Agents offer a convenient level of granularity at which to add redundancy a key factor in developing robust software. Blindly adding code introduces more errors, makes the system more complex, and renders it harder to understand. However, adding more code can make software better, if it is added in the right way. As this article describes, the key concepts appear to be redundancy and the appropriate granularity.

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Agent Societies: Magnitude And Duration, Michael N. Huhns Jan 2002

Agent Societies: Magnitude And Duration, Michael N. Huhns

Faculty Publications

If you only need agents to search the Web for cheap CDs, scalability is not an issue. The Web can support numerous agents if each acts independently. In short order, however, billions of embedded agents that sense their environment and interact with us and other agents will fill our world, making the human environment friendlier and more efficient. These agents will need not only scalable infrastructures and communication services, but also scalable social services encompassing ethics and laws. Research projects are under way around the world to develop and deploy such services. The author takes a look at the critical …

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Making Agents Secure On The Semantic Web, Csilla Farkas, Michael N. Huhns Jan 2002

Making Agents Secure On The Semantic Web, Csilla Farkas, Michael N. Huhns

Faculty Publications

Agents were designed to collaborate and share information. While highly desirable for interoperability, this feature is scary from the security perspective. Illegal inferences, supported by semantic Web technology and ontologies, might enable users to access unauthorized information. In addition to semantic associations and replicated data with different sensitivity, malicious agents could also exploit statistical inferences. Although each agent in a system might behave in a desired and secure way, their combined knowledge could be used to disclose sensitive data. The research community must therefore develop and implement techniques that allow control over released data. To answer the questions related to …

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A Dipolar Coupling Based Strategy For Simultaneous Resonance Assignment And Structure Determination Of Protein Backbones, Fang Tian, Homayoun Valafar, James H. Prestegard Nov 2001

A Dipolar Coupling Based Strategy For Simultaneous Resonance Assignment And Structure Determination Of Protein Backbones, Fang Tian, Homayoun Valafar, James H. Prestegard

Faculty Publications

A new approach for simultaneous protein backbone resonance assignment and structure determination by NMR is introduced. This approach relies on recent advances in high-resolution NMR spectroscopy that allow observation of anisotropic interactions, such as dipolar couplings, from proteins partially aligned in field ordered media. Residual dipolar couplings are used for both geometric information and a filter in the assembly of residues in a sequential manner. Experimental data were collected in less than one week on a small redox protein, rubredoxin, that was 15N enriched but not enriched above 1% natural abundance in 13C. Given the acceleration possible with partial 13C …

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Consensus Ontologies: Reconciling The Semantics Of Web Pages And Agents, Larry M. Stevens, Michael N. Huhns Jan 2001

Consensus Ontologies: Reconciling The Semantics Of Web Pages And Agents, Larry M. Stevens, Michael N. Huhns

Faculty Publications

As you build a Web site, it is worthwhile asking, "Should I put my information where it belongs or where people are most likely to look for it?" Our recent research into improving searching through ontologies is providing some interesting results to answer this question. The techniques developed by our research bring organization to the information received and reconcile the semantics of each document. Our goal is to help users retrieve dynamically generated information that is tailored to their individual needs and preferences. We believe that it is easier for individuals or small groups to develop their own ontologies, regardless …

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Automating Supply Chains, Michael N. Huhns, Larry M. Stevens Jan 2001

Automating Supply Chains, Michael N. Huhns, Larry M. Stevens

Faculty Publications

A recent study found that supply-chain problems cost companies between 9 and 20 percent of their value over a six-month period (T.J. Becker, 2000). The problems range from part shortages to poorly utilized plant capacity. When you place this in the context of the overall business-to-business (B2B) market expected to reach US$7 trillion by 2004 (37 percent of which is projected to be e-commerce sales), it is easy to see that effective supply-chain management (SCM) tools could save companies billions of dollars. Attempts to automate solutions to these problems are complicated by the need for the different companies in a …

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Trust And Persistence, Paul A. Buhler, Michael N. Huhns Jan 2001

Trust And Persistence, Paul A. Buhler, Michael N. Huhns

Faculty Publications

We rely on computers to control our power plants and water supplies, our automobiles and transportation systems, and soon our economic and political systems. Increasingly, software agents are enmeshed in these systems, serving as the glue that connects distributed components. Clearly, we need mechanisms to determine whether these agents are trustworthy. What do we need to establish trust? Agents are often characterized by features such as autonomy, sociability, proactiveness, and persistent identity. This latter feature is key in determining trust. When agents operate over an extended period, they can earn a reputation for competence, timeliness, ease of use, and trustworthiness, …

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Probability And Agents, Marco Valtorta, Michael N. Huhns Jan 2001

Probability And Agents, Marco Valtorta, Michael N. Huhns

Faculty Publications

To make sense of the information that agents gather from the Web, they need to reason about it. If the information is precise and correct, they can use engines such as theorem provers to reason logically and derive correct conclusions. Unfortunately, the information is often imprecise and uncertain, which means they will need a probabilistic approach. More than 150 years ago, George Boole presented the logic that bears his name. There is concern that classical logic is not sufficient to model how people do or should reason. Adopting a probabilistic approach in constructing software agents and multiagent systems simplifies some …

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Philosophical Agents, John R. Rose, Michael N. Huhns Jan 2001

Philosophical Agents, John R. Rose, Michael N. Huhns

Faculty Publications

Abstraction is the technique we use to deal with complexity. What is the proper kind and level of abstraction for complex software agents? We think it would be reasonable to endow agents with a philosophy. Then, by understanding their philosophies, we can use them more effectively. To endow agents with ethical principles, developers need an architecture that supports explicit goals, principles and capabilities, as well as laws and ways to sanction or punish miscreants. All of the ethical approaches described in this article are single-agent in orientation and encode other agents implicitly.

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Inside An Agent, José M. Vidal, Paul A. Buhler, Michael N. Huhns Jan 2001

Inside An Agent, José M. Vidal, Paul A. Buhler, Michael N. Huhns

Faculty Publications

When we discuss agent-based system construction with software developers or ask students to implement common agent architectures using object-oriented techniques, we find that it is not trivial for them to create an elegant system design from the standard presentation of these architectures in textbooks or research papers. To better communicate our interpretation of popular agent architectures, we draw UML (Unified Modeling Language) diagrams to guide an implementer's design. However, before we describe these diagrams, we need to review some basic features of agents. The paper considers an architecture showing a simple agent interacting with an environment. The agent senses its …

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Hop Integrity In Computer Networks, Mohamed G. Gouda, E.N. Elnozahy, Chin-Tser Huang, Tommy M. Mcguire Nov 2000

Hop Integrity In Computer Networks, Mohamed G. Gouda, E.N. Elnozahy, Chin-Tser Huang, Tommy M. Mcguire

Faculty Publications

A computer network is said to provide hop integrity iff when any router p in the network receives a message m supposedly from an adjacent router q, then p can check that m was indeed sent by q, was not modified after it was sent, and was not a replay of an old message sent from q to p. We describe three protocols that can be added to the routers in a computer network so that the network can provide hop integrity. These three protocols are a secret exchange protocol, a weak integrity protocol, and a strong integrity protocol. All …

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3d Outside Cell Interference Factor For An Air-Ground Cdma ‘Cellular’ System, David W. Matolak May 2000

3d Outside Cell Interference Factor For An Air-Ground Cdma ‘Cellular’ System, David W. Matolak

Faculty Publications

We compute the outside-cell interference factor of a code-division multiple-access (CDMA) system for a three-dimensional (3-D) air-to-ground (AG) "cellular-like" network consisting of a set of uniformly distributed ground base stations and airborne mobile users. The CDMA capacity is roughly inversely proportional to the outside-cell interference factor. It is shown that for the nearly free-space propagation environment of these systems, the outside-cell interference factor can be larger than that for terrestrial propagation models (as expected) and depends approximately logarithmically upon both the cell height and cell radius.

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An Agent-Based Global Economy, Michael N. Huhns Jan 2000

An Agent-Based Global Economy, Michael N. Huhns

Faculty Publications

Many people are buying music CDs over the Web, but with multiple retail sites offering the same CDs, how do you decide which retailer to buy from? Typically, you visit a few sites and choose the one with the lowest price. Shopbotsshopping agents that automatically search the Internet to obtain information about prices and other attributes of goods and servicesare ideal helpers for such a task.1 The better ones can visit hundreds of sites, giving price-conscious consumers a powerful tool that could work to the detriment of some retailers.

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The Emergence Of Language Among Autonomous Agents, Piotr Gmytrasiewicz, Michael N. Huhns Jan 2000

The Emergence Of Language Among Autonomous Agents, Piotr Gmytrasiewicz, Michael N. Huhns

Faculty Publications

Suppose some autonomous shopbot agents had been representing us by dealing with a vendor's pricebot, and suppose they didn't share an agent communication language (ACL). What should they know at a fundamental level, what could each point to, and how could they establish a common language? Recent research at the University of Texas at Arlington has shown that agents first establish a common vocabulary, progress to a primitive language similar to human pidgin, then enrich the language's grammar to develop a creole, and eventually arrive at a full-blown ACL. During this process, the vocabulary and grammatical structures most important to …

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Sensors + Agents + Networks = Aware Agents, Michael N. Huhns, Sreenath Seshadri Jan 2000

Sensors + Agents + Networks = Aware Agents, Michael N. Huhns, Sreenath Seshadri

Faculty Publications

Software agents are being deployed in increasing numbers to help users find and manage information, particularly in open environments such as the Internet. For the most part, they operate independently and are typically designed to be aware only of their users and the environment in which they perform their tasks. Thus, they fail to take advantage of each other's abilities or results. For example, a shopping agent might periodically access several online databases to find the best price for a music CD and then purchase it if the price falls below its user's threshold. Other agents might be tracking prices …

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Agent Teams: Building And Implementing Software, Michael N. Huhns Jan 2000

Agent Teams: Building And Implementing Software, Michael N. Huhns

Faculty Publications

Agents will become fundamental building blocks for general-purpose Internet-based software. The software may not display any explicitly agent-like characteristics, but it will exhibit the benefits of tolerance to errors, ease of maintenance, adaptability to change, and speed of construction that agents provide. Moreover, an agent-based approach to software development can lead to new types of software solutions that might not otherwise be obvious. The author considers how an approach based on teams of active, cooperative, and persistent software components, that is agents, shows special promise in enabling the rapid construction of robust and reusable software.

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Online Auctions, Michael N. Huhns, José M. Vidal May 1999

Online Auctions, Michael N. Huhns, José M. Vidal

Faculty Publications

Auctions on the Internet can involve not only consumers, but also businesses. They can form dynamically and enable the exchange of goods much as stock exchanges manage the buying and selling of securities. But because auctions have a wide scope and a short lifetime, the opportunistic behavior needed for successful interaction requires agents to both participate in and manage auctions. The article focuses on the use of software agents in such Internet based auctions

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Exploiting Expertise Through Knowledge Networks, Michael N. Huhns, Larry M. Stevens Jan 1999

Exploiting Expertise Through Knowledge Networks, Michael N. Huhns, Larry M. Stevens

Faculty Publications

The paper discusses the necessary capabilities of knowledge networks: categorizing (the ability to classify Web pages and other unstructured data automatically); hyperlinking (the ability to add to each item of information appropriate pointers to other relevant items of information); alerting (the automatic notification of users and agents to new information that might be of interest to them); and profiling (the construction of models of users and agents to describe their interests and expertise).

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Personal Ontologies, Michael N. Huhns, Larry M. Stevens Jan 1999

Personal Ontologies, Michael N. Huhns, Larry M. Stevens

Faculty Publications

Corporations can suffer from too much information, and it is often inaccessible, inconsistent, and incomprehensible. The corporate solution entails knowledge management techniques and data warehouses. The paper discusses the use of the personal ontology. The promising approach is an organization scheme based on a model of an office and its information, an ontology, coupled with the proper tools for using it.

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Benevolent Agents, Michael N. Huhns, Abdulla Mohamed Jan 1999

Benevolent Agents, Michael N. Huhns, Abdulla Mohamed

Faculty Publications

Some agents roaming the Web these days are benevolent-for example, they may clean up stalled or failed database transactions, or share query results that may have cost substantial resources to acquire and might consume more to share. The Agent Behavior Testbed is a tool for studying the economics of agent altruism. As more agents hit the Internet, benevolence and cooperation will help with overall efficiency and productivity. The paper discusses benevolent agents on the Web.

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Networking Embedded Agents, Michael N. Huhns Jan 1999

Networking Embedded Agents, Michael N. Huhns

Faculty Publications

Most of us will soon be managing an intranet in our homes, though we might not realize it. We might also be surprised at the devices that will be networked together. Just about every electrical device now contains one or more microprocessors. Designers typically find this a cost-effective way to provide device functionality, even when much of a processor's power is unnecessary or unused. For example, my coffee maker contains a processor, even though the appliance needn't be very smart and wastes most of its CPU cycles. Nevertheless, it is cheaper to include a general-purpose microprocessor than to incorporate custom …

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Negotiating For Goods And Services, Michael N. Huhns, Anuj K. Malhotra Jan 1999

Negotiating For Goods And Services, Michael N. Huhns, Anuj K. Malhotra

Faculty Publications

Can a negotiation protocol be both fair and “envy-free” when more than two agents are involved? The authors consider how envy-free apportioning is more difficult than fair apportioning, but both can help to manage critical resources. They discuss an envy-free protocol and agent-based Web auctions.

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Cognitive Agents, Michael N. Huhns, Munindar P. Singh Jan 1998

Cognitive Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

Several researchers have proposed using cognitive concepts as a semantic basis for agent communications (M.N. Huhns and M.P. Singh, 1997). One of the leading candidates for such a semantics is based on Arcol, the communication language used within Artimis. Interestingly, this application (not only of Arcol, but also in general) appears extremely misguided. The intentional concepts are well suited to designing agents, but are not suited to giving a basis to a public, standardizable view of communication. A challenge for using the cognitive concepts is that although they are natural in several respects and can guide implementations, full blown implementations …

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Personal Assistants, Michael N. Huhns, Munindar P. Singh Jan 1998

Personal Assistants, Michael N. Huhns, Munindar P. Singh

Faculty Publications

Already there are simple personal agents to help with some of our shopping. There are agents to track stocks in our portfolios, advise us on how to use particular software products, and arrange meetings within corporate workgroups. However, none of these agents takes more than one aspect of our activities into account, nor do they adapt easily to our preferences. Personal assistants, on the other hand, are agents that can represent individuals on the Web. They help users in their day-to-day activities, especially those involving information retrieval, negotiation, or coordination. A personal assistant might schedule a meeting and then, based …

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Workflow Agents, Michael N. Huhns, Munindar P. Singh Jan 1998

Workflow Agents, Michael N. Huhns, Munindar P. Singh

Faculty Publications

Software agents as user agents, resource agents, and brokers may be able to enhance usefulness of workflow applications. Workflow technology is important to network computing because workflows exist naturally wherever distributed resources are interrelated. The problem with current workflow technology is that it is often too rigid. The lack of freedom accorded to human participants causes workflow management systems to appear unfriendly. As a result, they are often ignored or circumvented. This rigidity also causes productivity losses by making it harder to accommodate the flexible, ad hoc reasoning of human intelligence. Another challenge is that system requirements are rarely static. …

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