<p>The field of athletic training is growing rapidly and needs to be recognized in our institutions of higher education. Currently, there are 80 colleges and universities throughout the United States with undergraduate athletic training curriculums accredited by the National Athletic Trainers' Association (NATA) and several more who have internship programs in athletic training (N.A.T.A. Staff, personal communication, January 18, 1993).</p> / Master of Science

This paper describes a model of the software requirements development process. The need for this model and its application to system engineering is addressed. Model design is accomplished through the use of system dynamics, and the computer code was written using the Dynamo III simulation language. The model is divided into four subsystems and the components of each subsystem are discussed in some detail. The applicability of this model as an addition to an earlier, comprehensive software development model is also discussed. Finally, this paper shows the effects of manipulating several key model parameters on model output. / Master of Science

The Department of Defense (DoD) has recently undergone radical changes as a result of the collapse of the Soviet Union. As the United States continues to downsize its conventional armed forces, new threats, both inside and outside its borders, are emerging. These new challenges include narco-traffickers, rising crime rates, and a massive immigration of illegal aliens that threaten to overwhelm our already strained social programs. This scenario is complicated by limited government resources that can no longer afford the luxury of expensive military equipment which takes an average of seven to ten years to design, manufacture, and field. Government agencies desperately need low-cost, off-the-shelf hardware that can reduce manpower requirements and be rapidly fielded to meet these emerging threats. <p> In response to these new threats and declining budgets, a new system, TAClink, recently "came into being". TAClink is a single-man portable system that can receive, record, display, and play back imagery transmitted from a surveillance aircraft. <p> This report describes how the systems engineering process¹ was applied to the development of TAClink. Throughout the process, the author applied the most techniques he could to maintain a "top-down" systems engineering approach. However, the author was operating under severe constraints: no internal or external funding, only a two month period to produce a prototype, and poorly defined system requirements. Consequently, the approach deviated from a pure systems engineering process and became "bottoms-up." <p> TAClink was designed, prototyped, tested, and delivered to the US Army last year. The system was recently upgraded (TAClink II) using technological advances and feedback from operational users. The system is designed using commercial off-the-shelf components, resulting in a dramatic savings in size, weight, and cost over the existing Army ground station. TAClink is currently manufactured in Arlington, VA and has been operationally deployed with U.S. Forces in this nation's war on drugs. <p> The author and Mr. Gerald V. Bate worked side-by-side to develop TAClink for its rapid fielding. Their combined efforts are largely responsible for the creation and success of the system. / Master of Science

<p>A crush test fixture for measuring energy absorption of flat plate specimens from an earlier study was redesigned to eliminate the problem of binding of the load transfer platen with the guide posts. Further modifications were to increase the stroke, and combine the two scaled test fixtures into one. This new crush test fixture was shown to produce load displacement histories exhibiting well developed sustained crushing loads over long strokes.</p> <p> An experimental study was conducted on two material systems: AS4/3502 graphite/epoxy, and a hybrid AS4-Kevlar/3502 composite. The effect of geometric scaling of specimen size, the effect of ply-level and sublaminate-Ievel scaling of the stacking sequence of the full scale specimens, and the effect of trigger mechanism on the energy absorption capability were investigated.</p> <p> The new crush test fixture and flat plate specimens produced peak and sustained crushing loads that were lower than obtained with the old crush test fixture. The trigger mechanism used influenced the specific sustained crushing stress (SSCS). The results of this study indicated that to avoid any reduction in the SSCS when scaling from the 1/2 scale to full scale specimen size, the sublaminate-level scaling approach should be used, in agreement with experiments on tubes. The use of Kevlar in place of the graphite 45° plies was not as effective a means for supporting and containing the 0° graphite plies for crushing of flat plates and resulted in a drop in the SSCS. This result did not correlate with that obtained for tubes.</p> / Master of Science

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The goal of this project was to develop part of an environment that would allow the creation of distributed applications using the actor model in an heterogeneous environment. The actor model is realized by ACT++, a C++ framework for building actor applications. This project is concerned only with the problems of the creation, destruction and the invocations of the methods of a remote server actor. A related project concerns the client activities and the message transfer. Three elements comprised the solution: a run-time loading entity using the facilities of a dynanlic linker called "DId," a query service to identify the classes present in an object file using a tool derived from the source-level debugger "GDB" and a directory service allowing both classes and actors to be located in memory. The solution was tested on several simple examples. The fundamental features of C++ and of the actor model have been retained in the distributed environment. The typing mechanisms used by C++ are preserved, and both polymorphic and overloaded functions are available. Regarding the actor model, the main components, namely actors, behaviors, messages and the replacement behavior are present. However, a choice had to be made concerning the communication model and the argument passing semantics. C++ and the actor model support synchronous and asynchronous communications, respectively. The latter was chosen, as our solution was based on the actor model and its message passing mechanism. C++ allows by reference parameters, while in the distributed environment, only by value parameters are allowed. It appears that the tools derived from GDB and DId could also be used as a software engineering tool, allowing the dynamic linking and unlinking of a class, the creation of objects of that class, and the invocation of its methods for testing purposes. / Master of Science

see document / Master of Science

The systems engineering approach was used to implement conformal solder mask in the manufacture of printed wiring boards (PWBs) at the AT&T Microelectronics Richmond Plant. Existing solder mask had a planar surface causing low soldering process yields on PWBs using Surface Mount Technology (SMT). SMT reduced product cost by allowing 50% more components per unit area of a PWB. Conformal solder mask processing reduced the mask thickness applied, and allowed future SMT PWBs to be manufactured. Coating methods to apply solder mask were evaluated. Two methods, curtain coating and electrostatic spray (ESS) f were chosen since no method satisfied all operational requirements. Ciba Geigy's Probimer process was implemented to meet short term revenue and capacity requirements. Probimer was an industry standard but had performance limitations. ESS met all requirements but required additional development to select a solder mask material and obtain customer approval. / Master of Science