Social accounts of learning and human knowledge have led to attempts to reorganize schools as learning communities. This paper examines the utility of the World Wide Web for aiding in the construction of school-based ...
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Social accounts of learning and human knowledge have led to attempts to reorganize schools as learning communities. This paper examines the utility of the World Wide Web for aiding in the construction of school-based and work-based learning communities. An ordered list of interactions is provided to characterize the depth of students' entry into new learning communities. Current offerings on the World Wide Web are then surveyed in terms of these categories. Finally, proposals are advanced for enhancing the architecture of the WWW to facilitate its use for the creation and operation of learning communities.
作者：
Edinberg, DBack, KMcVeigh, JDavid Edinberg is a senior naval architect with Advanced Marine Enterprises in Arlington
Virginia. His experience in ship design includes dynamic analysis of ship's deck systems intact and damaged stability calculations trim and stability support during ship designs and structural design. For the last two years he has led a team of engineers in the dynamic analysis of the sideport ramp system employed on the Navy's new sealift ships. He graduated in 1979 with a B.S. degree in naval architecture and marine engineering from the University of Michigan. Keith Back is a senior engineer with Advanced Marine Enterprises in Arlington
Virginia. He is currently the section chief for the Advanced Visualization Group. He has more than ten years experience developing and using CAD models in the ship design environment. For the past two years he has led the development of visualization techniques and models for use in simulations for current ship design programs. He graduated in 1985 with a B.S. degree in aerospace and ocean engineering from Virginia Polytechnic Institute and State University. USALt. Col. Joe McVeigh USA
is currently deputy program manager (Army) for PMS 385 the Strategic Sealift Office at NavSea. As the senior U.S. Army officer on staff he is responsible for interfacing with the program's primary customer in addition to his assignment as T&E director. Lt. Col. McVeigh graduated with a B.Sc. from the United States Military Academy in 1978 after which he received his 2nd lieutenant's commission in the U.S. Army Transportation Corps. In 1991 he received M.S. degrees in mechanical engineering and naval architecture and marine engineering from MIT. Lt. Col. McVeigh's previous assignments have included: platoon leader/XO 870th Terminal Transfer Company program support officer/XO/contract administrator
DLA operations staff officer/Exercise Branch chief. Special Forces Europecompany commander
598th Medium Truck Company commander Movement Control Team Mannheim and Army watercraft systems engineer
U.S.
The Navy's Sealift program had several unique problems associated with it which have been addressed using innovative modeling and simulation tech niques. These techniques fall under two categories: visualization a...
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The Navy's Sealift program had several unique problems associated with it which have been addressed using innovative modeling and simulation tech niques. These techniques fall under two categories: visualization and dynamic analysis. This paper will discuss the employment of these techniques and the impact their application has had in the program. Also examined will be various difficulties that were encountered in the application of these techniques. Commercial-off-the-shelf (COTS) visualization tools were used to model the interior Ro/Ro spaces on the four classes of new construction and conversion ships now being procured. These models were employed for vehicle maneuvering simulations, operator familiarization and visualization of the results of an analysis of the loading and unloading of Ro/Ro vehicles. A COTS dynamic analysis system was used to simulate dynamic behavior during the assembly/deplopment and retrieval/disassembly of the side port ramp using the ships' cranes. These analyses supported reviews of design configurations, proposed handling procedures, and in conjunction with extensive post-processing, operability assessments for system operation. In a parallel effort, an interactive crane simulator was developed to support on-going engineering studies, indoctrination, and test and evaluation purposes. Lessons learned have been applied to other activities at the Naval Sea Systems Command. Critical areas were the validation and maintenance of up-to-date configuration data for the visual models, adaptive levels of detail to meet the requirements of each study objective, and the need to provide comprehensive documentation of models.
作者：
CHENG, BHDEAN, JSMILLER, RWCAVE, WLBill H. Cheng:is a physical scientist in the Numerical Fluid Dynamics Branch
Computation Mathematics and Logistics Department David Taylor Research Center (DTRC) Bethesda MD. Since joining DTRC in 1981 he has been the project leader for the XYZ Free Surface (XYZFS) Program. He received a B.S. in mechanical engineering from the National Taiwan University and a M.A.Sc. in mechanical engineering from the University of British Columbia and a S.M. degree in oceanography and meteorology from Harvard University. Mr. Cheng is a registered professional engineer in the Commonwealth of Virginia and a member of American Society of Mechanical Engineers and Sigma Xi. His experience in fluid dynamics has included theory experiments and computations. He has been the author and coauthor of numerous technical reports and papers. Janet S. Dean:is a mathematician in the Numerical Fluid Dynamics Branch
DTRC. She attended the College of William and Mary and received her B.S. degree in mathematics from The George Washington University. Mrs. Dean assisted Charles Dawson in the development of the original XYZFS Program. She has worked on improving and extending the capabilities of XYZFS and on the application of supercomputers to fluid dynamics problems. Ronald W. Miller:is a mechanical engineer in the Numerical Fluid Dynamics Branch
DTRC. He received his B.A. degree in mathematics from the University of Maryland—Baltimore County Campus in 1984 and his M.S. in ocean and marine engineering from The George Washington University in 1988. Mr. Miller is responsible for the preparation of hull geometry data used in ship hydrodynamic analysis computer codes and the graphical visualization of output from such codes. William L. Cave III:graduated from Stevens Institute of Technology in 1986 with a B.E. degree in ocean engineering. He is currently a naval architect in the Design Evaluation Branch
Ship Hydromechanics Department DTRC. He has been involved with model testing and evaluation of the CV-41 FFG-7 class USNSHayesCG-47 class
A computational capability has been developed to predict and visualize the flow about podded propulsors appended to the 154-foot transom stern research vessel, R/V Athena . The computer generation of a complex geometr...
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A computational capability has been developed to predict and visualize the flow about podded propulsors appended to the 154-foot transom stern research vessel, R/V Athena . The computer generation of a complex geometric model for the hull and appendages is an important part of this new capability. The flow field is computed using a free surface potential flow method. The steady flow induced by the propulsor is simulated by an idealized propeller model (actuator disk). The upstream effects of an actuator disk are examined and results are compared to the case without an actuator disk. Computed results for the inflow to the propeller disk are presented as velocity vector plots and contour plots. Harmonic analyses are performed on the computed velocity components. The numerical results can be used in conjunction with experiments performed at DTRC to aid in the design of podded propulsors. These flow studies are used to examine the proper alignment of the pod/strut system with the aim of obtaining the optimal flow into the propeller. The combined numerical and experimental approach is shown to be an efficient way to evaluate complex hull forms with podded propulsors. This powerful design approach can be used for future Navy ship designs.
Recent hardware advances for both enhanced computing and interactive graphics are used to improve the effectiveness of three-dimensional engineering simulations. The two examples presented, drawn from structural engin...
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Recent hardware advances for both enhanced computing and interactive graphics are used to improve the effectiveness of three-dimensional engineering simulations. The two examples presented, drawn from structural engineering, deal with the fully nonlinear transient dynamic analysis of frames and boundary element stress analysis.
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