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Center for Computational Science and Advanced Distributed Simulation (C2SDS)

ANNUAL REPORT
September 29, 2000 - January 15, 2002

Advanced Distributed Simulation Research Consortium

(ADSRC)

 

Parallel and Distributed Evaluation, Visualization, and AI Reasoning to Advanced DIS Technology

 

none

 

 

Army Research Office

Grant No. DAAH04-95-1-0250

 

Grambling State University

Department of Mathematics and Computer Science

Grambling, LA 71245


Table of Contents

 

1.       Project Progress Reports from Task Teams

           1.1       ADS Architecture Design and Evaluation (ADS-ADE) Task                                2 - 13

                        Coordinator: Ratan K. Guha

             1.2       ADS Visualization and Synthetic Environment (ADS-VSE) Task                       14 - 28

                        Coordinators: Patrick Bobbie/Henry Williams

             1.3       ADS Knowledge Base Systems (ADS-KBS) Task                                           29 - 37

                        Coordinator: Richard Al󼯰>

 

            1.4       Student Outreach and Training Program Task                                                    40 - 48

                        Coordinator: Muddapu Balaram/Y. B. Reddy

 

2.       Publications, Presentations and Personnel

 

          2.1       ADS Architecture Design and Evaluation (ADS-ADE) Task                              50 - 51

                        Coordinator: Ratan K. Guha

 

            2.2       ADS Visualization and Synthetic Environment  (ADS-VSE) Task                      52 - 53

                        Coordinator: Patrick Bobbie/Henry Williams

 

            2.3       ADS Knowledge Base Systems (ADS-KBS) Task                                           54 - 56

                        Coordinator: Richard Al󼯰>

 

            2.4       Student Outreach and Training Program (ADS-KBS) Task                               57 - 61

                        Coordinator: Muddapu Balaram/ Y. B. Reddy

 

 

            Appendix: Publication Abstracts                                                           62 - 80

SECTION 1.

 

PROJECT PROGRESS REPORTS

FROM TASK TEAMS


 

1.1 ADS Architecture Design and Evaluation (ADS-ADE) Task

Task Coordinator: Ratan K. Guha

 

OVERVIEW

 

Objectives and Significance:

The main objectives of the research performed by the ADS Architecture Design and Evaluation team are: (1) to develop techniques to model/evaluate the performance of large scale ADS systems, (2) to develop algorithms for improving the scalability and reducing the bandwidth requirement of networks supporting distributed interactive simulation, and (3) to improve solution techniques used by tools for the modeling and performance evaluation of ADS systems.

 

Specifically, the main objective for the final year of this project was to continue our research in (1) advanced networking and wireless technology, (2) synchronization problems of distributed systems, (3) relevance filtering, (4) analytic and simulation tools for transport protocols and (5) algorithm developments for multimedia servers. For general-purpose tools, we have worked on developing easily accessible interval computation software, which can reliably perform fundamental interval arithmetic, set operation and bound elementary interval functions.

 

Networked and distributed system design is the major thrust of our research. In one of our wireless projects, we developed algorithms to control and optimize the number of non-critical calls in a video-intensive mobile environment supporting critical applications. In another project, we designed a hybrid cellular/ad-hoc architecture and evaluated its performance and fault-tolerance. For synchronization problem of distributed systems, we extended our triangular level coteries to trapezoidal and incomplete triangular level coteries and developed an algebraic method for generating coteries. The successful implementation of efficient relevance filtering in network gateways would help solve one of the challenges facing the design of highly scalable DIS and HLA systems.

 

Army Relevance:

Wireless and mobile communication technologies will continue to play increasingly important role in the various functions of armed forces. One of our projects addresses the problem of controlling wireless connections and improving QoS while achieving graceful degradation of non-critical calls during congestion. Categorizing connections into critical and non-critical makes our algorithm suitable for Army applications requiring the prioritization of a selected class of calls. The development of efficient channel assignment and handoff protocols is another critical problem facing the designers of third generation wireless systems. Our research addresses the real-time performance issues of handoff protocols and seeks to develop efficient channel assignment and handoff schemes.  Our wireless research also helps in the effort to incorporate live vehicles in military simulation training exercises.

 

The research on filtering and routing spaces is crucial to the scalability of HLA currently being developed under the auspices of the Defense Modeling and Simulation Office as the DoD-wide standard for simulation. The results of this research have provided good insight into the behavior of relevance filtering schemes, their real-time performance and their reliability.  With this insight, the development of reliable and efficient filtering methods is greatly enhanced.

 

For synchronization in a distributed system, the special class of non-token-based algorithm, known as the quorum based approach, requires each process to only exchange messages with a subset of specific nodes in the distributed system. The quorum-based approach is attractive due to its well-defined concept, low message overhead, and its capability to tolerate both the site and link failures. The development of this concept will contribute to the efficiency and fault tolerance capabilities of HLA systems.

 

Other subtasks of our research provide useful utilities for an array of military and civilian applications. These subtasks include caching schemes and data allocation algorithms for distributed multimedia servers, an online interval calculator, and a parallel global optimization software tool.

 

Accomplishments:

Several teams have been formed to work on several sub-tasks. Areas of accomplishments include simulation and analytic models for transport protocols, algorithms to control and optimize the number of non-critical calls in wireless environments supporting critical applications, real-time protocols for channel assignments and handoff handling in mobile wireless environments, trapezoidal and incomplete triangular level quorums for distributed mutual exclusion, relevance document filtering, data caching scheme and data allocation algorithms for distributed multimedia servers, an online interval calculator, and a parallel global optimization software tool. The details of these accomplishments are elaborated in the following sections.

 

Managing QoS for Wireless Cells with Critical Load

S. Rakshit and R. Guha (UCF)

 

Research Objectives and Significance:

Wireless networks are becoming increasingly important to both military and civilian applications. Their advantages include the rapid development and deployment of the communications infrastructure as well as their high degree of mobility. Compared to wired networks, however, wireless networks have higher bit error rates and have a more constrained bandwidth. It is therefore essential to design and employ efficient algorithms for scheduling and prioritizing user calls, managing bandwidth allocation and the graceful performance degradation during times of congestion. These design and management issues are the main target of this project.

 

Army Relevance:

Wireless networks are a major technology thrust in many military and civilian applications.  Improving QoS in wireless networks and the graceful degradation of such networks during congestion are important goals of the Army.

 

Methodology:

We divide the connections (calls) in wireless networks into two categories: a) critical calls and b) non-critical calls. Critical calls are assigned higher priority than non-critical ones and are allowed preemptive access to the network resources. We have given special attention to video-intensive application environments. Both simulation and analysis have been used in designing and fine-tuning our control algorithms.

 

Accomplishments:

  1.  We have designed a novel algorithm to control and optimize the number of non-critical calls in a video-intensive mobile environment supporting critical applications.
  2. We have published two papers in conference proceedings: the first paper was presented in the Summer Simulation Conference, July 2001, and the second paper was presented in the IEEE Globecom Conference, November 2001.

Relevance Filtering for Scalable DIS/HLA Systems

 

Y. B. Reddy (GSU)

 

Research Objectives and Significance:

The goal of our research in this area is to examine the design of relevance filtering schemes, analyze their reliability, evaluate and improve their filtering efficiency by using various techniques. The successful implementation of efficient relevance filtering in network gateways would help solve one of the challenges facing the design of highly scalable DIS and HLA systems. In HLA, the Data Distribution Management is the RTI component responsible for increasing the scalability of the training exercise and reducing the traffic among federates. Filtering is obtained by allowing federates to declare and use routing spaces and custom filtering schemes. Improving the effectiveness of filtering greatly improves HLA scalability.

 

Army Relevance:

The research on filtering and routing spaces is crucial to the scalability of HLA currently being developed under the auspices of the Defense Modeling and Simulation Office as the DoD-wide standard for simulation. The results of this research have provided good insight into the behavior of relevance filtering schemes, their real-time performance and their reliability. With this insight, the development of reliable and efficient filtering methods is greatly enhanced.

 

Methodology:

An HLA routing space is a multidimensional coordinate system by which federates can implement a filtering mechanism without requiring the RTI to have complex domain specific knowledge. The three components of a vector location are used as the three variables of a three-dimensional routing space. We have used a circular region of interest to determine the relevancy of transmitted messages and implemented filtering algorithms at the sending receiving gateways. Both analysis and simulation have been used to study the performance and reliability of relevance filtering algorithms.

 

Accomplishments:

Filtering at transmission and filtering at reception are two important requirements in all DIS exercises. Algorithms for distance based filtering and grid based filtering was developed and used in local and gateway dead-reckoning. There are other approaches to filter the irrelevant messages. One of the methods is calculating the fitness of the entity using genetic algorithm approach. The approach provides better results because relevance of the message normally depends upon type of entity, position of entity, direction of its movement, and other characteristics. The total characteristics are coded into blocks of bits and test for fitness. The messages are delivered to the best-fit entities. The GA method is faster and more accurate. Some work has been done using GA approach. Other approaches in progress include:

  •        Mapping the entities located in the same terrain region to hosts located in the same LAN helps to localize the set of hosts that would need to receive state update messages from each entity.
  •        Grid based data distribution.
  •        Estimating the entity position using previous state and related information.

 

 

 

Hybrid Cellular/Ad-hoc Wireless Network Architectures

 

M. Bassiouni and W. Cui (UCF)

 

Research Objectives and Significance:

The cellular architecture plays an eminent role in the field of wireless data communications. The mobile terminals only establish direct links with the nearest base stations and therefore routing is much simplified. The stationary base stations must be deployed across all areas of desired coverage and the failure of one base station blocks all services in its area of coverage. On the other hand, ad-hoc networks show more benefits in terms of mobility, ease of deployment and tolerance to node failure. To get the benefits of both architectures, we have studied layered cellular/ad-hoc network architectures that allow cellular and ad-hoc protocols running on different layers of nodes. Layers of nodes will then be organized and coordinated to provide a flexible and robust network environment.

 

Army Relevance:

A hybrid cellular/ad-hoc architecture will be an alternative and robust solution to dynamically deployable wireless data networks. The new architecture will have lower cost than pure ad-hoc solutions since mature technology and products can be applied.

 

Methodology:

We have built a mobile wireless simulator which is running on Linux and Sun stations. Different mobility models can be easily specified during the simulation. Teletraffic is currently assumed to be Poisson, however, alternative traffic model can be incorporated if necessary.

 

Accomplishments:

  1.   We have designed and simulated a new protocol that allows the base stations to move in a cellular environment. In addition, several enhancement measures have also been proposed and studied.

 

  1.   We have published a refereed chapter in a book entitled ?Next  Generation Wireless Networks?  edited by S. Tekinay, Kluwer Publishing, December 2000.

 

 

 

 


 Trapezoidal and Incomplete Triangular Level Coteries and Coterie Transformations

 

R. Guha and J. Chu (UCF)

 

Research Objectives and Significance:

We have developed a new approach, called triangular level coterie, to generate relatively small and equal sized quorums and we have studied the properties satisfied by the triangular level quorums. In quorum based approach, each process only exchange messages with a subset of specific nodes in the distributed system before entering its critical section. The specific subset is called a quorum. The set of quorums is called a coterie. The quorum-based approach is attractive due to its well-defined concept, low message overhead, and its capability to tolerate both the site and link failures. However, triangular level coteries can be developed only if the number of nodes is m(m+1)/2 for some integer m. The objectives of this project are to (1) to extend our work to the case where the number of nodes are not m(m+1)/2 for some integer m and (2) develop a general concept of coterie transformation to generate a new coterie from a given coterie. The significance of this proposed work is that for any number of nodes we will be able to generate relatively small and equal sized quorums.

 

Army Relevance:

The HLA, designated as the standard architecture for distributed simulation systems, can only be implemented as a large distributed system. For a system like this, it is desirable to have the quorum size as small as possible to enter a critical section. On the other hand, to increase the fault tolerance capability, the coterie size should be as large as possible. This project addresses issues that influence the efficiency and fault tolerance capabilities in the implementation of HLA.

 

Methodology:

We have developed the concept of triangular level quorums as follows. Let U = {1, 2, ?, N} be the nodes in a distributed system. Let the m sets S1, S2, ?, Sm be subsets of U such that Si Ǽ/span> Sj = Ƽ/span> for 1 ? i ? j ? m, | S1 | = 1, | Si | = | Si-1 | + 1 for 2 ? i ? m, and U = S1 ȼ/span> S2 ȼ/span>? ȼ/span> Sm. The m-level structure S1, S2, ?, Sm forms an equilateral triangular structure, and the level coterie constructed from the triangular structure is called an m-level triangular level coterie, denoted as Dm.  Because |S1| = 1, and | Si | = | Si-1 | + 1 for i = 2, 3, ?, m, we have | Si | = i for i = 1, 2, ?, m.

Let U={1, 2, 3, ?, N} be the N nodes in a distributed system. The N nodes are logically arranged into m levels S1, S2, ?, Sm, where Si are non-empty subsets of U. Si Ǽ/span> Sj = Ƽ/span>, for all 1 ? i ? j ? m, and U = S1 ȼ/span> S2 ȼ/span>?ȼ/span> Sm. If  | Si | = i for 1 ? i ? m, then the ND level coterie Dm = Q1 ȼ/span> Q2 ȼ/span> ? ȼ/span> Qm is called an m-level triangular level coterie, q μ/span> Dm is an m-level triangular level quorum, where Qi, 1 ? i ? m,  are defined as

 

                           m

      Q1 = {S1 ȼ/span> ( ȼ/span> {Xj}) | Xj μ/span> Sj, j = 2, 3, ?, m}

                          j=2

 

                           m

      Q2 = {S2 ȼ/span> ( ȼ/span> {Xj}) | Xj μ/span> Sj, j = 3, 4, ?, m}

                          j=3

       ?

                           m

       Qi = {Si ȼ/span> ( ȼ/span> {Xj}) | Xj μ/span> Sj, j = i+1, i+2, ?, m}

                        j=i+1

        ?

       Qm = {Sm}     

 

If the number of nodes is not m(m+1)/2 for some integer m, and equal-sized quorums are required, then we can form a trapezoid level structure {S1, S2, ?, Sm } such that Si Ǽ/span> Sj = Ƽ/span> for 1 ? i ? j ? m, | S1 | = r >1, | Si | = | Si-1 | + 1 for 2 ? i ? m, and U = S1 ȼ/span> S2 ȼ/span>? ȼ/span> Sm. The m-level structure S1, S2, ?, Sm forms an m-level trapezoid level structure. The quorum size of any quorum in the coterie is (r+m-1). We have shown that a trapezoid level coterie is a dominated coterie.

 

If m(m+1)/2 < N < (m+1)(m+2)/2, then N cannot be logically arranged into a complete equilateral triangular level structure. If a non-dominated level coterie is required and unequal-sized quorums are acceptable, then a non-dominated level coterie can be constructed from an incomplete equilateral triangular level structure.

 

In the above, we have developed level coteries from geometric structure. It is also possible to utilize an algebraic approach to construct level coteries. Coterie transformations for dominated as well as non-dominated cases have been studied.

 

Accomplishments:

The following tasks have been accomplished

 

  1. Our paper entitled ?Triangular Level Quorums for Distributed Mutual Exclusion? has been published in the Journal of Computer Systems Science and Engineering, Vol. 15, No. 6, pp. 373 - 384, November 2000.

 

  1. We have developed trapezoid level coteries and investigated incomplete triangular level coteries.

 

  1. We have also developed the concept of coterie transformation. A coterie transformation is a function that generates a new coterie from a given coterie.

 

 


Data Caching and Data Allocation for Multimedia Servers

 

R. Guha and J. Wang (UCF)

 

Research Objectives and Significance:

Two most important features of the multimedia data, especially video data, are their large storage and bandwidth requirement.  Recent advances in workstation architecture, high-speed networking, high-speed modem and storage technologies have set the foundation of delivering the streaming media to the ordinary families.  Together with the improvement in hardware technologies, advances in software technologies, such as data compression, Internet browser and streaming media player, have brought the Video-on-Demand from concept to reality.  On the other hand, the rapid growth of the Internet and WWW has driven the technology industry into a new arena in which Web hosting and content hosting have become very popular businesses.  Many companies operate several distributed data centers where the other companies? Web servers and Web contents are hosted. In this distributed multimedia environment, there are many challenges in storing, retrieving and delivering the multimedia data due to the storage capacity limitation, I/O bandwidth limitation and communication bandwidth limitation. Those constraints become even obvious in the distributed Video-On-Demand (VOD) environment.

 

Army Relevance:

Internet, WWW and distributed Video-On-Demand will play significant role in Army?s training and distributed simulation.

 

Methodology:

Two most important features of the video objects are their large storage space requirement and large I/O bandwidth requirement.  The traditional LRU memory page replacement algorithms are not suitable for continuous video objects.  We propose a Bi-directional Fragmental Pipelining (BFP) technique and its variable buffer size data caching scheme BFPV to reduce the disk I/O bandwidth requirement for multimedia servers.

Multimedia data management has been thoroughly studied in the non-distributed multimedia environment.  The data management in this environment focuses on device level data allocation and management.  We discuss the server level data allocation problems in the distributed multimedia environment, especially in the distributed Video-on-Demand systems.  We proposed two data allocation algorithms, Bandwidth Weighted Partition (BWP) algorithm and Popularity Based (PB) algorithm, based on the network bandwidth and storage capacity limits of the distributed multimedia servers.

 

Accomplishments:

  1. We have developed a novel data caching scheme for multimedia servers. We have also developed data allocation algorithms for distributed multimedia servers.
  2. Our paper entitled ?Efficiently Allocating Video Data in Distributed Multimedia Applications? has been accepted for publication in the Journal of Applied System Studies- Special Issue on Distributed Multimedia Systems with Applications.
  3. We have also published two papers in conference proceedings: the first paper was presented in the Conference on Simulation Methods and Applications, November 2000, and the second paper was presented in the 8th ACM International Conference on Multimedia, November 2000.

 


Efficient Algorithms for Real-time and Transport Protocols in Wireless Networks

 

M. Bassiouni, C. Fang and H. ElAarag (UCF)

 

Research Objectives and Significance:

Real-time protocols with linear time and space complexity are poised to have good scalability features. These protocols are needed in different functions of the layered communications stack. The transport protocol in the fourth layer of this stack has a particularly important role in connection establishment and reliability. Our goal in this project is to improve the design of these types of protocols for wireless networks and/or improve our ability to characterize their behavior and predict their performance.

 

Army Relevance:

Scalable real-time protocols are needed for efficient wireless communications. Constructing accurate models for the transport protocols enhances our ability to better design and utilize these protocols in the different Army application environments.

 

Methodology:

For the real-time handoff problem, our approach uses a non-compact initial assignment of nominal channels to neighboring cells and utilizes a set of pointers in each base station to implement an efficient channel assignment/reassignment strategy. The resulting approach greatly simplifies the selection process and avoids the expensive computation and message exchanges typically needed by dynamic channel allocation schemes. The low communication overhead of the scheme can be further reduced via control thresholds.  For the transport protocols, we used detailed simulation models and analytical models to study the performance of TCP in both ideal and non-ideal network environments.

 

Accomplishments:

  1.   We have designed a real-time channel allocation protocol that possesses the desirable features of real-time algorithms: the execution time per handoff request has a constant time complexity, the number of transmitted messages per request is small, and the space overhead is also O(1). Performance simulation results show that the scheme achieves low blocking probability and is therefore suitable for handling handoffs of real-time connections in linear topology wireless networks.

 

  1. We developed simulation and analytical models for the throughput and transfer time of TCP as a function of the file size and TCP parameters. Our models enabled us to obtain good insights into the behavior and performance of TCP in different ideal and non-ideal environments.

 

  1.   We have published the following papers: i) a paper in the Journal of Computer  Communications, December 2001, ii) a paper in  the Journal of Wireless Personal Communications, December 2001, and iii) a paper in the Proceedings of the Winter Computer Simulation Conference, December 2000.

 


A Standard for Interval Basic Linear Algebra Software

 

C. Hu (UHD)

 

Research Objective and Significance:

The objective of this project is to establish a standard for interval basic linear algebra subprograms. Interval computation provides reliable computational results. Basic linear algebra software technology (BLAST) is essential in computing. We have set the first interval BLAS standard that can be used for both computer vendors and software developers to support interval computations as well as scientific computing users to solve various application problems.

 

Army Relevance:

The reliability of computational solutions is one of the most important aspects in all Army related computing. Basic linear algebra software is essential to almost all computations required by Army applications. The interval BLAS standard will help software developers and users to apply interval computing and obtain reliable computational solutions for Army related scientific computing applications.

Methodology:

 

To establish the standard, we have actively participated in the Basic Linear Algebra Software Technology (BLAST) group and worked closely with experts from the National Institute of Standard Technology, Sandia National Laboratory, Oak Ridge National Laboratory, Bell Lab, NAG, Intel, Hewlett Packard, NEC, Tara Computers, University of California at Berkeley, University of Tennessee at Knoxville, and other participants in the Basic Linear Algebra Software Technology (BLAST) group since 1995.  We have also kept active e-mail communications with experts in the interval computing community.

 

Accomplishment:

The interval BLAS standard we established has been included in the BLAS document. The interval BLAS standard includes interval vector operations, interval vector-matrix operations, matrix-matrix operations for interval general, symmetric, banded, triangular, triangular banded, and symmetric banded matrices. It contains the interfaces for about 200 routines in Fortran77, Fortran 95 and C languages.

 


ParaGlobSol 0.1 and 0.2

Parallel Global Optimization Software Package

 

C. Hu (UHD)

 

 

Research Objective and Significance:

The objective of this project is to improve the performance of a generic non-linear global optimization interval software package named GlobSol through parallel/distributed computing. Non-linear global optimization is a fundamental research problem. With interval computing, GlobSol can reliably find global optimum in a given domain for many application problems. Our parallel implementation has significantly improved the performance of this package. 

 

Army Relevance:

ParaGlobSol is a generic global optimization package. It can be used to solve optimization problems in the Army. 

 

Methodology:

  • Our parallel implementations are on networked Sun Ultra workstations.
  • We use MPI (the Message Passing Interface) to distribute the workload to multiprocessors.
  •  By using the backward compatibility of Fortran 90, we have developed an MPI working environment that supports interval computations with Fortran 90. The original package GlobSol was written in Fortran 90. However, MPI does not have a Fortran 90 implementation.
  •  Our implementation is coarse-grained SPMD (Single Program Multiple Data).
  •   Both static and dynamic load-balancing techniques are applied to improve the overall efficiency.

 

Accomplishments:

  •   Both ParaGlobSol 0.1 and 0.2 have been implemented and tested.
  •   The source programs, installation and user guide have been put online at the URL:

http://www.mscs.mu.edu/~globsol/ParaGlobSol.html

 


1.2 ADS Visualization and Synthetic Environment (ADS-VSE) Task

 

Task Coordinators: Henry Williams

 

OVERVIEW

 

Objectives and Significance:

The main objectives of the overall ADS-VSE task are to: to develop and evaluate algorithms for graphics and visualization; to analyze the real-time performance of algorithms in synthetic environments; and 3) to tailor the algorithms to the simulation of phenomenological elements like terrain, fire, and smoke in distributed synthetic environments.  To accomplish these goals, the ADS-VSE team embarked on the following subtasks. Details of each subtask, or subproject, have been individually reported following this overview, with the tasks' titles participants, and affiliations.

  1.       One subtask focused on developing a model to simulate fire in a virtual environment using a distributed parallel-computing environment. The approach involved developing a two-dimensional (2-D) simulation of fire that improves on current 2-D fire simulations and uses Monte Carlo simulation techniques and stochastic models like the Ising Model as templates.
  2.       The purpose of a subtask was to develop algorithms to determine the   equivalence of two or more geometric objects.  This simply means taking various three-dimensional models and systematically performing a point-wise comparison of the properties/attributes at each coordinate (x, y, z) point of the objects.  The goal was to develop a tool for comparing graphical objects based on their underlying 3D structure, and also tailorable to related work in the ADS-VSE task.
  3.       A subtask emphasized the insertion of graphical images into a simulated smoke model in a dynamic virtual environment. We initially limited our concentration on the exploration and development of ways to reduce the large volume of image datastreams which is created when smoke is simulated in our Ising simulation model. This subtask's focus shifted from the fire model to graphical issues in the modeling of smoke.
  4.       A subtask included reverse engineering a popular network based game to build components suitable for DIS simulations.  We have included a formalization of the process to aid in future tasks.
  5.       The objective of this subtask was to develop a methodology and an environment for creating distributed speech applications. The goal was to develop JSBB (Java Speech Builder), a visual modeling tool for specifying both distributed and non-distributed speech applications.
  6.       An image compression tutorial was initiated to address the need for a central web-based introduction to image formats and compression.  This tutorial gives a brief overview and comparison of different compression methods.
  7.       The objective of a sub-project was to develop a two-dimensional (2-D) fire simulation for accurate, graphical representation of the physical properties and features of fire. The fundamental component of the work is a 2-D fire simulation program that mimics the random behavior of fire without the effects of wind. In this subproject, we focused on the theoretical underpinnings such a heat transfer equations, temperature difference equations, and stochastic models.
  8.       A subtask was to develop a finite element model for heat propagation on the presumption that further phenomenological models could be realized more efficiently and accurately.  The current model is one-dimensional and will be expanded to 2D and eventually 3D.
  9.       A subproject, focusing on the performance issues of parallel algorithms, complemented another which uses heat transfer equations and other models for modeling fire behavior.  In the parallel algorithm subtask, it was assumed that the Message Passing Interface (MPI) system could reduce the time necessary to process large lattices both mathematically and graphically.  A parallel version of the Ising algorithm was implemented and currently runs in the MPI environment on a cluster of SGI workstations.
  10.   Fuzzy models were applied to the physical-based modeling of dust particles in virtual environments.  This allowed for the realistic simulation of the behavior of these particles.  The specific goal was to simulate dust behavior as generated by a fast moving vehicle in a virtual environment, e.g., across a simulated battlefield terrain.
  11.   One subtask was on the transformation of 3D polygon-based representation, which allows morphing, control, and correspondence and interpolation. The goal was to develop techniques for visualizing objects as their representations are transformed from one mode into another.  This subtask also required a technique for object recognition based on pattern matching.
  12.   This subtask focused on developing a graphical user interface (GUI) to JAVA JDBC, an API that allows access to any database that has the proper JDBC driver. The goal was to develop an interface that hides the details of the underlying DBMS software used to create a specific database, allowing for a simplified interface to develop queries in standard SQL DDL (Data Definition Language).

 

Army Relevance:

The effects of fire and its resulting smoke can have a significant impact on the strategic and tactical goals of a battle unit.  Military personnel training in virtual world simulations and using training simulators may experience a realistic representation of these phenomenological elements that occur in real world theaters of war.  As such, the effectiveness of combat simulators may improve as simulated fires and smoke mimic their real counterparts. Consequently, the cost of effectively training soldiers may be reduced.

 

The results of the graphical object comparison project will help in object recognition/identification by matching the subject against a database of target images.  For example, the identification of enemy weapons/vehicles can be performed by use of this geometric analysis technique.

 

The incorporation of real-time obscurants such as smoke into computer simulations makes the virtual battlefield much more realistic. This further allows for military training at higher levels of complexity thereby enhancing readiness for battle. The smoke-modeling subtask was an investigation into the plausible and realistic representation of this phenomenological element.

 

Voice-based signals can be incorporated, with the proper level of security, into the transmission of commands among officers in battlefield environments.  The spoken-language work also provides a way to manage multiple simulators in a virtual battlefield as well as the control of battlefield vehicles, e.g. mine sweepers, where human involvement, or control, is life

threatening. Image transmission among commanding officers must be swift for effective battle management. Having the most efficient compression methods, which reduce the space and time complexities in the overall image processing, is vital to this goal.

 

Arguably, sound, mathematical models that encompass heat transfer, temperature, chemical reactions, and stochastic effects are essential to the precise calculation and simulation of fire.  These models also add accuracy to the realistic representation of phenomenological effects in virtual battlefield simulations.

 

The real-time, virtual train environment (VTE) subtask provides a testbed for students to develop real-time algorithms for simulating mobile or vehicular entities in virtual environments.  The results of this subtask will offer insight into the mechanisms for remote control of such devices and insertion of speech through dialogues.  Further, the results of this subproject will be useful for maneuvering obstacle courses and vehicular guidance in simulated environments.

 

The fuzzy modeling subtask will offer a capability to generate realistic virtual environments in simulating dust generated by virtual battlefield vehicles like fast moving tanks.

 

The morphing subtask also will be applicable to the simulation of object transformations from one mode into another, especially, in the simulation of camouflaged entities or presentation of such effects.

 

The database graphical interface tool will provide a unified approach to developing queries that target different databases without regard to the underlying logical and physical database definitions.  This will make different data formats, e.g., images, text, video, and audio databases to be uniformly queried.

 

 

Methodologies:

The ADS-VSE group has developed and improved on the computation and visualization of a two-dimensional fire simulation in its endeavor to create a three-dimensional 3-D fire simulation for virtual environment training simulations. In the subtasks involving geometric object modeling and analysis, several techniques and tools used in this research include Open GL, Java, C++ and other object-oriented software tools; algorithms for correlating different three-dimensional geometric objects to determine the objects' equivalence; and incorporation of the Voronoi and Delaunay triangulation algorithms.

 

As an extension of the 2D-fire modeling and simulation, we concentrated our efforts on the design, development, testing and implementation of a Graphical Control Engine (GCE), for representing and controlling the behavior of smoke in a virtual battlefield simulation.  We also concentrated on the development of formal mathematical tools for modeling the features and behavior of fire.  To develop FireSim2, the fire simulation system, we used large data arrays, temperature difference equations, incorporated Monte Carlo simulation techniques, and used the Ising Model as a stochastic modeling template. We integrated optimal probability values in order to introduce the predictable and erratic behavior of fire.  Further, we used a distributed computing environment, the MPI system, to map lattices of particles (from the 2D Ising model) in order to reduce the computational time required to process large lattices. The MPI distributed software architecture also allowed for the concurrent and efficient computation and visualization of the stochastic behavior of the simulated fire elements (particles).

 

In the spoken-language research our approach to design and implementation of multiple user speech applications depended on models for agent modeling, agent behavior representation, and distributed computing paradigms for propagating dialogues across multiple platforms to simulate interactions.

 

We studied and compared various data compression algorithms. A web site was developed which allows for the comparison of various image formats like JPEG, GIF, TIFF, PNG, and Fractal.  To facilitate this effort, a JAVA applet was created to compare compressed images to their original representations.  We developed another JAVA-based Deflated Compression Technique (DCT) algorithm for interactive manipulation of images.

 

The real-time control of a moving (model) train using multiple tracks required both hardware devices, e.g., sensors and solenoids. We added electronic controls and sensors to an existing non-computerized model train layout to create the train's terrain. Two transformers controlled the speed and direction of the two train cabs. Three control units were developed namely a cab control, a sensor control and a switch control. In addition, we set up thirteen manual switches, which were placed under computer control by adding a set of control solenoids, providing a directional pulse to each existing switch solenoid.  Each switch control was manipulated by signals sent through an RS-232 port. Further, we tried to use a standard PC digital camera connected to one of  the serial ports of the PC that controls the train. The idea was to video-capture the terrain data for further analysis to provide feedback control information on obstacles or defective tracks to alert the virtual conductor; however, the camera provided several problems.

 

Using rigid-particle dynamics and fluid dynamics, a physical-based model was develop to represent the structure and behavioral properties of dust particles.  A three dimensional (3D) morphing technique was developed in Open Inventor environment to test algorithms that drive the morphologies of objects.  Most of the algorithms that were developing for the morphing problem were drawn from computer graphics, e.g., projections, clipping,  and interpolations.  And the database GUI subtask involved heavy understanding and usage of JAVA systems.

 

Accomplishments:

FireSim2 is currently functional and being expanded from 2-D to 3-D. The output window is an array of 3600 panels that simulate pixels. With each iteration of the simulation, each of the panels is updated regardless of whether its color value changes.  A distributed parallel processing technique was investigated to increase the speed of the computation and to expand the capacity of the program to process large arrays. The MPI implementation yielded some performance improvements, or speedup, in particular, as the number of sublattices increases the parallel version slightly outperformed the serial execution.  The FireSim2 program currently runs on any platform that supports a stable Java environment. It was principally developed in the FAMU ADSRC laboratory.

 

The main accomplishment of the object comparison task was the development of an algorithm that performs the initial step in the graphical analysis process. The algorithm would incorporate the Voronoi diagrams and Delaunay Triangulation algorithms, which is currently under development.

 

Work on the Graphical Control Engine (GCE) subtask generated learning experiences for the students. In particular, they spent considerable time learning OpenGL and other software tools in our environment. Most of the work was done in the areas of the design of the GCE and the development of a tutorial on wavelets and other useful DSP and image processing information.

 

We have a fully functional prototype of JSBB. The JSBB environment contains a toolbar that lists the various dialogue states used to construct the dialogue. The developer chooses a state from the toolbar and adds it to the canvas, the main area in the center of the tool.  The dialogue states are then connected to form a finite-state dialogue model.

 

Further, students were involved in developing JSBB applications, or tools, for:

  •       speech-based interaction with a moving train (part of the VTE subproject),
  •       locating agents in a distributed environment, and
  •       voice-based calendar or scheduler.

 

The web-based tutorial system for image understanding and data compression was successfully completed and currently at :http://www.adsrc.famu.edu.  It allows a user to view the original image by selecting an image from the list of given choices. The user can then select the compression ratio.  The image of the user's choice is then displayed on the applet.

 

In the moving train subtask, Java objects were written for each physical object. The software components that were developed to control the simulation in real-time included the following Java objects - a cab, switch and sensor. The environment, which is functional, is set up in the graduate laboratory in the Computer Information Science Department at FAMU.

 

An investigation into the behavior of dust centered on the physical problem of airflow around moving vehicles using separated flow, particularly, the flow of turbulence at the boundary and vortex of the vehicle.  The appropriate mathematical models for modeling the movement of dust in this context were investigated.  Several steps were completed in the morphing project, resulting in the development of routines in C++. And a GUI tool for constructing a uniform SQL-based query system which dovetails a JAVA JDBC API, was developed in the database interfacing subtask.

 

 


Spoken Language Dialogue in a Distributed Environment

 

C. Allen, T. Weatherspoon (Student), K. Bartholomew (Student)

 

Research Objectives and Significance:

The objective of this research is to develop a methodology and software development environment for creating distributed speech applications. A distributed speech application allows multiple users, distributed throughout a computer network, to interact with the application using speech. Our goal is to develop JSBB, a visual modeling tool for specifying both distributed and non-distributed speech applications. The primary purpose of this research is to provide a platform that can support the development of distributed and non-distributed speech applications. The platform will be usable by both novices and experts in speech applications, and will be flexible enough to support a broad range of speech applications, for example interactive simulations.

 

 

Army Relevance:

This research has potential applications in battlefield management simulations. This work provides a way to manage multiple participants of a speech-based battlefield simulation, where the participants are distributed throughout a network. For example, voice commands can be incorporated, with the proper level of security, into the transmission of commands among officers in battlefield environments.

 

Accomplishments:

We have a fully functional prototype of JSBB. A speech application developer uses the JSBB development environment to visually model a finite-state dialogue. This dialogue model is then used to generate a working speech application. JSBB contains a toolbar that lists the various dialogue states used to construct the dialogue. The developer chooses a state from the toolbar and adds it to the canvas, the main area in the center of the tool.  The dialogue states are then connected to form a finite-state dialogue model.

 

We have developed several applications to demonstrate and test the features of JSBB. Those applications are:

 

  • Speech-Based Interaction with a Railroad Train ? This application allows someone to control a model railroad train in real-time. The user can start or stop the train, as well as control the speed, all using speech.

  • Locator Agent ? This speech-based agent moves around in a distributed environment trying to locate an item (for example a book) on behalf of someone. The agent moves from machine to machine speaking to the owner of the machine.

 

 

 Our future work will involve adding support for automatic learning of the dialogue. Constructing a spoken language system is labor intensive and requires a lot of expertise. One way to overcome these obstacles is to use machine-learning techniques to help the developer design the dialogue model. We will investigate machine-learning algorithms and incorporate a learning module in the current development environment. This learning module will use a corpus of human-to-human conversations to generate a preliminary dialogue model for the speech application.

 

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