Naval Postgraduate School

About: Naval Postgraduate School is a education organization based out in Monterey, California, United States. It is known for research contribution in the topics: Tropical cyclone & Boundary layer. The organization has 5246 authors who have published 11614 publications receiving 298300 citations. The organization is also known as: NPS & U.S. Naval Postgraduate School.

Networked virtual environments: design and implementation

Abstract: 1. The Promises and Challenges of Networked Virtual Environments. What Is a Networked Virtual Environment? Graphics Engines and Displays. Control and Communication Devices. Processing Systems. Data Network. Challenges in Net-VE Design and Development. Network Bandwidth. Heterogeneity. Distributed Interaction. Real-Time System Design and Resource Management. Failure Management. Scalability. Deployment and Configuration. Conclusion. References. 2. The Origin of Networked Virtual Environments. Department of Defense Networked Virtual Environments. SIMNET. Distributed Interactive Simulation. Networked Games and Demos. SGI Flight and Dogfight. Doom. Other Games. Academic Networked Virtual Environments. NPSNET. PARADISE. DIVE. Brick Net. MR Toolkit Peer Package. Others. Conclusion. References. 3. A Networking Primer. Fundamentals of Data Transfer. Network Latency. Network Bandwidth. Network Reliability. Network Protocol. The BSD Sockets Architecture. Sockets and Ports. The Internet Protocol. Introducing the Internet Protocols for Net-Ves. Transmission Control Protocol. User Datagram Protocol. IP Broadcasting Using UDP. IP Multicasting. Selecting a Net-VE Protocol. Using TCP/IP. Using UDP/IP. Using IP Broadcasting. Using IP Multicasting. Conclusion. References. 4. Communication Architectures. Two Players on a LAN. Multiplayer Client-Server Systems. Multiplayer Client-Server, with Multiple-Server Architectures. Peer-to-Peer Architectures. Conclusion. References. 5. Managing Dynamic Shared State. The Consistency-Throughput Tradeoff. Maintaining Shared State Inside Centralized Repositories. Reducing Coupling through Frequent State Regeneration. Dead Reckoning of Shared State. Conclusion. References. 6. Systems Design. One Thread, Multiple Threads. Important Subsystems. Conclusion. References and Further Reading. 7. Resource Management for Scalability and Performance. An Information-Centric View of Resources. Optimizing the Communications Protocol. Controlling the Visibility of Data. Taking Advantage of Perceptual Limitations. Enhancing the System Architecture. Conclusion. References. 8. Internet Networked Virtual Environments. VRML-Based Virtual Environments. Virtual Reality Transfer Protocol. Internet Gaming. Conclusion. References. 9. Perspective and Predictions. Better Library Support. Toward a Better Internet. Research Frontiers. Past, Present, and Future. References. Appendix: Network Communication in C, C++, and Java. Using TCP/IP from C and C++. Managing Concurrent Connections in C and C++. Using TCP/IP from Java. Managing Concurrent Connections in Java. Using UDP/IP from C and C++. Using UDP/IP from Java. Broadcasting from C and C++. Broadcasting from Java. Multicasting from C and C++. Multicasting from Java. References. Index. 0201325578T04062001

A Model of Marine Aerosol Generation Via Whitecaps and Wave Disruption

Abstract: We have, over the past several years, as one element in the development of a time-dependent model of the aerosol population of the marine atmospheric boundary layer, attempted to define, in terms of aerosol droplet radius (r) and 10m-elevation wind speed (U), a model of open-ocean sea-surface aerosol generation. This source function is represented by the expression dF(r, U)/dr, which states the rate of production of marine aerosol droplets, per unit area of the sea surface, per increment of droplet radius. In the initial modeling efforts only the indirect aerosol production mechanisms associated with the bursting of whitecap bubbles (see Figure 1) were considered. The model for sea surface aerosol generation by the indirect mechanisms, first introduced in our Canberra SSAG-1 (Monahan, et al, 1979) and Manchester SSAG-2 (Monahan, 1980) papers, is given by Equation 1, where W is the $${\rm{d}}{{\rm{F}}_0}/{\rm{dr = W}}{\tau ^{ - 1}}{\rm{dE/dr}}$$ instantaneous fraction of the sea surface covered by whitecaps, τ is the time constant characterizing the exponential whitecap decay (measured in seconds), and dE/dr is the differential whitecap aerosol productivity, i.e. the number of droplets per increment droplet radius produced during the decay of a unit area of whitecap (expressed in m−2 μm−1 ). The necessary expression for W(U) was obtained from shipboard photographic observations of white- caps (Monahan, 1971; Toba and Chaen, 1973), while values for τ and dE/dr were derived from measurements made using the University College, Galway, whitecap simulation tank.

Interannual and Interdecadal Variations of the East Asian Summer Monsoon and Tropical Pacific SSTs. Part I: Roles of the Subtropical Ridge

Abstract: The interannual relationship between the East Asian summer monsoon and the tropical Pacific SSTs is studied using rainfall data in the Yangtze River Valley and the NCEP reanalysis for 1951‐96. The datasets are also partitioned into two periods, 1951‐77 and 1978‐96, to study the interdecadal variations of this relationship. A wet summer monsoon is preceded by a warm equatorial eastern Pacific in the previous winter and followed by a cold equatorial eastern Pacific in the following fall. This relationship involves primarily the rainfall during the pre-Mei-yu/Mei-yu season (May‐June) but not the post-Mei-yu season (July‐August). In a wet monsoon year, the western North Pacific subtropical ridge is stronger as a result of positive feedback that involves the anomalous Hadley and Walker circulations, an atmospheric Rossby wave response to the western Pacific complementary cooling, and the evaporation‐wind feedback. This ridge extends farther to the west from the previous winter to the following fall, resulting in an 850-hPa anomalous anticyclone near the southeast coast of China. This anticyclone 1) blocks the pre-Mei-yu and Mei-yu fronts from moving southward thereby extending the time that the fronts produce stationary rainfall; 2) enhances the pressure gradient to its northwest resulting in a more intense front; and 3) induces anomalous warming of the South China Sea surface through increased downwelling, which leads to a higher moisture supply to the rain area. A positive feedback from the strong monsoon rainfall also appears to occur, leading to an intensified anomalous anticyclone near the monsoon region. This SST‐subtropical ridge‐monsoon rainfall relationship is observed in both the interannual timescale within each interdecadal period and in the interdecadal scale. The SST anomalies (SSTAs) change sign in northern spring and resemble a tropospheric biennial oscillation (TBO) pattern during the first interdecadal period (1951‐77). In the second interdecadal period (1978‐96) the sign change occurs in northern fall and the TBO pattern in the equatorial eastern Pacific SST is replaced by longer timescales. This interdecadal variation of the monsoon‐SST relationship results from the interdecadal change of the background state of the coupled ocean‐atmosphere system. This difference gives rise to the different degrees of importance of the feedback from the anomalous circulations near the monsoon region to the equatorial eastern Pacific. In a wet monsoon year, the anomalous easterly winds south of the monsoon-enhanced anomalous anticyclone start to propagate slowly eastward toward the eastern Pacific in May and June, apparently as a result of an atmosphere‐ocean coupled wave motion. These anomalous easterlies carry with them a cooling effect on the ocean surface. In 1951‐77 this effect is insignificant as the equatorial eastern Pacific SSTAs, already change from warm to cold in northern spring, probably as a result of negative feedback processes discussed in ENSO mechanisms. In 1978‐96 the equatorial eastern Pacific has a warmer mean SST. A stronger positive feedback between SSTA and the Walker circulation during a warm phase tends to keep the SSTA warm until northern fall, when the eastward-propagating anomalous easterly winds reach the eastern Pacific and reverse the SSTA.