John Mark Pullen

An Architecture for Web-Services Based Interest Management in Real Time Distributed Simulation

The Experimentation Command and Control Interface (XC2I) project has developed an architecture for a Web-service based viewer/controller for use with distributed simulations supporting military experiments. As part of this activity, a capability for Interest Management with three functions is being created. The functions are Role-Based Access Control (RBAC), Area of Interest Management (AOIM), and Aggregation Interest Management (AGIM). While the approach is compatible with High Level Architecture (HLA) for Modeling and Simulation, primary information exchange takes place using the Web services, i.e. software-to-software messaging interfaces that operate over Web protocols such as XML/SOAP. This paper presents a Web Services Internet Management (WSIM) architecture designed to achieve these capabilities in a way that is compatible with simulations using the HLA. The protocols and information flow structure are described, along with the architectures design rationale, interest management rules, and plans for its implementation. The paper concludes with a description of potential for future development of WSIM, including adoption of the Command and Control Information Exchange Data Model (C2IEDM) and use of Overlay Multicast for data distribution.

Using Web services and data mediation/storage services to enable command and control to simulation interoperability

The extensible battle management language project has implemented XML based data mediation services to translate from legacy XML schemas into XML schemas, based on a common tag set generated from the command and control information exchange data model (C2IEDM). The C2IEDM was developed by NATO to enable interoperation among operational command and control (C2) systems of coalition forces. XBMLs ability to exchange simulation information based on C2IEDM enables a major expansion in interoperability, in that C2 systems now can be coupled with modeling and simulation software. The benefit of our specific data mediation approach is that legacy systems are required only to provide information exchange interfaces based on XML, as the adaptation of such systems is done by configuring the layers of the recommended architecture. We present the architecture and operational principles used to achieve interoperation in this way.

Enabling real-time distributed virtual simulation over the Internet using host-based overlay multicast

Many-to-many multicast transmission is an essential network capability for scalable distributed simulation. The many open issues that make network-layer multicast impractical over the Internet today are likely to continue to be insurmountable and to prevent deployment in a manner that will meet the quality of service (QoS) and many-to-many multicast needs of real-time distributed virtual simulation (RT-DVS). We propose an alternative approach, whereby the IP multicast function is relocated to the simulation host computer and also used to provide for QoS enabled services on a priority basis. This paper explores the concept of such a host-based multicast system with QoS and its suitability for RT-DVS. The paper defines the basic requirements of a host-based multicast protocol to support RT-DVS and proposes a quantitative model for evaluation of system alternatives.

Implementation of Host-Based Overlay Multicast to Support of Web Based Services for RT-DVS

Growing demand for use of Internet/Web-based services in real-time distributed virtual simulation (RT-DVS) and other real-time applications is fueling extensive interest in overlay multicast protocols. These applications demand Quality of Service (QoS) and many-to-many multicast services that are not available in underlying Internet services today. This paper describes an early implementation of an overlay multicast protocol designed to support many-to-many multicast for RT-DVS applications called Extensible Modeling and Simulation Framework Overlay Multicast (XOM). We first describe the architecture and key design considerations of XOM. We then provide preliminary results from lab experiments with our prototype. Our results indicate that we can achieve performance objectives for support of web-based services for RT-DVS.

Pros and cons for teaching courses in the classroom and online simultaneously

In adding an online delivery option to an existing graduate program in computer science, important choices include (1) synchronous or asynchronous delivery and (2) for synchronous delivery, whether to deliver classroom and online teaching simultaneously. This paper describes the decisions made in adding an online option to an MSCS program, which now is maturing. The factors in favor of and against simultaneous delivery are discussed in detail and the conclusions reached for one particular program are described, including experience gained in the process and an open-source software system developed to support this form of delivery.

Moodle-integrated open source synchronous teaching

It is well understood that the two prevalent approaches to distance education, synchronous and asynchronous, can be combined to good effect. However, existing open source software generally is separated into these two categories. This paper introduces an open source capability that combines the popular Moodle asynchronous learning management system with a new synchronous online teaching/conferencing system called MIST/C. This combination is supporting online delivery of the Masters programs in our Computer Science Department effectively. This paper describes the design and implementation of MIST/C and our experience using it to support Computer Science MS programs.

MIST/C: Open Source Software for Hybrid Classroom and Online Teaching

Educational research indicates that the two prevalent approaches to distance education, synchronous and asynchronous, exhibit synergy if combined. Our research addresses how to create the most effective, open source (and therefore robust and inexpensive) software to enable educators to exploit that synergy. The Moodle learning management system provides a high-quality asynchronous online learning environment, but until recently has lacked a matching synchronous component. This paper introduces synchronous open source software for filling that gap: a synchronous online teaching/conferencing system called MIST/C. The Moodle-MIST/C combination has demonstrated its effectiveness in online delivery of our Master of Science in Computer Science Department. MIST/C was created as an enhancement to the Network EducationWare system, on which we have reported in previous IASTED conferences. It was developed as open source software to work seamlessly with Moodle on all major platforms and also to be easy to install and operate. It also is tailored to support simulteaching: teaching a group of students in the hybrid mode delivering to classroom and online at the same time, which conserves teaching resources. This paper describes the design and implementation of MIST/C, including latest advanced features, and our experience using it to deliver our degree program.

An agent architecture for network support of distributed simulation

Continued research into distributed agent-based systems and evolving Web based technologies are opening up tremendous possibilities for the deployment of large scale and highly extensible and flexible simulation systems. However, the question remains as to how well agent and Web based simulation systems can use underlying network services. This is especially true for complex distributed simulations that have multiple participants and real-time data delivery requirements. This paper addresses the issue of interconnection patterns among Web-based simulation agents. We first describe a simple agent-oriented architectural extension to an existing distributed simulation system. Next, we present a set of interconnection algorithms between the agents in the system, under the assumption that only end-host multicast is available. We experimentally evaluate our approach under a number of different scenarios. Our results show that by using a proper connection strategy it is possible to get performance comparable to network-layer multicast for agent-based systems that use end-host multicast.

An International Experiment in Command and Control -- Simulation Interoperability Using Web Services

This paper addresses issues in interconnecting military command and control (C2) and simulation systems, using Web technologies and mediation via a common representation, the command and control information exchange data model (C2IEDM). The authors supported a NATO Exploratory Team that designed an experimental program to assess the approach and prepare for its use by coalitions. As part of that activity, the United States and France implemented an international demonstration of C2 and simulation systems interoperating using Web services and C2IEDM. This paper reports on how C2 and simulation systems were employed with Web technologies to achieve a successful demonstration in a very short time period, including experience gained in the process and plans for future development of C-BML capabilities

Better Online Teaching Support Using Open-Source Web Applications

This paper reports on combining emerging technologies for synchronous distance education in a student-implemented project. The goal is to realize, using latest web technologies, the MISTC open-source multimedia Internet client we developed earlier to support teaching in the classroom and online simultaneously. We summarize MISTCs capabilities, describe the development processes and tools utilized, and lessons learned.