Distributed computer communications in support of real-time visual simulations

Approved for public release; distribution is unlimited.Complex visual simulations can strain the capability of a single workstation. A mix of different workstations is often more economical than the use of a large processor for such simulations. Methods of communicating between such workstations are needed that allow the developer to spend effort on the simulation and not on communications. Simple protocols are developed to support both broadcast and direct-connect communications between workstations using TCP/IP on an Ethernet. Comparisons are made between broadcast and direct connect protocols. Keywords: Transmission control protocol(TCP); Ethernet; Computer networks. (KR)http://archive.org/details/distributedcompu00barrMajor, United States Marine Corp

Distributed computer communications in support of real-time visual simulations

Complex visual simulations can strain the capability of a single workstation. A mix of different workstations is often more economical than the use of a large processor for such simulations. Methods of communicating between such workstations are needed that allow the developer to spend effort on the simulation and not on communications. Simple protocols are developed to support both broadcast and direct-connect communications between workstations using TCP/IP on an Ethernet. Comparisons are made between broadcast and direct connect protocols. Keywords: Transmission control protocol(TCP); Ethernet; Computer networks. (KR)http://archive.org/details/distributedcompu00barrMajor, United States Marine CorpsApproved for public release; distribution is unlimited

Distributed computer communications in support of real-time visual simulations

The modern tactical commander has a flood of sensory and intelligence information at his disposal. A tool is required to sort that information, allowing the commander to choose the information that is most pertinent to the decisions he must make at that time. This study is the preliminary work on the command and control workstation of the future. The focus of this effort is in two areas. One is a user interface using multiple windows and a mouse controlled cursor. This interface allows the user to set up the display to give him the information he needs in a way that is easy for him to interpret. The second focus is preliminary work on a real-time display that presents the user with a three-dimensional picture of the situation. This initial display uses three resolutions to display large areas of Defense Mapping Agency Digital Terrain Elevation Data with near real time animationThis report was prepared in conjunction with research conducted for the Naval Ocean Systems Center and the Naval Underwater Systems Center and funded by the Naval Postgraduate School.http://archive.org/details/distributedcomputer00barrO&MN, Direct FundingNAApproved for public release; distribution is unlimited

Songbirds are Resilient to Hurricane Disturbed Habitats During Spring Migration

The Gulf of Mexico is a conspicuous feature of the Neotropical-Nearctic bird migration system. Traveling long distances across ecological barriers comes with considerable risks, and mortality associated with intercontinental migration may be substantial, including that caused by storms or other adverse weather events. However, little, if anything, is known about how migratory birds respond to disturbance-induced changes in stopover habitat. Isolated, forested cheniere habitat along the northern coast of the Gulf of Mexico often concentrate migrants, during weather conditions unfavorable for northward movement or when birds are energetically stressed. We expected hurricane induced degradation of this habitat to negatively affect the abundance, propensity to stopover, and fueling trends of songbirds that stopover in coastal habitat. We used spring banding data collected in coastal Louisiana to compare migrant abundance and fueling trends before (1993-1996 and 1998-2005) and after hurricanes Rita (2006) and Ike (2009). We also characterized changes in vegetative structure before (1995) and after (2010) the hurricanes. The hurricanes caused dramatic changes to the vegetative structure, which likely decreased resources. Surprisingly, abundance, propensity to stopover, and fueling trends of most migrant species were not influenced by hurricane disturbance. Our results suggest that: 1) the function of chenieres as a refuge for migrants after completing a trans-Gulf flight may not have changed despite significant changes to habitat and decreases in resource availability, and 2) that most migrants may be able to cope with habitat disturbance during stopover. The fact that migrants use disturbed habitat points to their conservation value along the northern coast of the Gulf of Mexico