Abstract – The Underwater Synchronous Scanner Imaging Model (USSIM) was developed as a software tool for exploring the design-trade space of the laser line scan system (LLSS). The critical software modules of USSIM have been subjected to a stressful validation process that relied on laboratory data collected with the LLSS. This validation effort demonstrated the utility of USSIM's predictive capabilities. This paper provides a description of the model and presents the results of the validation work.
This modeling effort was initiated as part of the development of an underwater laser line scan system (LLSS). This model provides an analytical capability for performing design–trade studies and to provide the means for estimating system performance in user–specified scenarios. This model is based on the small-angle scattering theory of Wells,1,2 the backscattering theory of Replogle,3,4 and standard linear system theory for incoherent imaging.5 In this first application of USSIM, estimates for the spatial frequency decay function, D(y), of the Well's theory are derived from the Duntley-Wilson empirical formula for the medium point spread function.6 This model fills a void in currently available software packages 7,8 which do not have the capability for analyzing underwater synchronous scanning systems. Validation of USSIM will occur in conjunction with laboratory tests of the LLSS.
This paper describes an approach to modeling a telecommunications network comprised of connected SONET 4-fiber bidirectional line switched rings (4F-BLSRs) for the purpose of assessing the network's reliability. This approach is this basis for the algorithms used in the NetPerm software. This paper is divided into four major sections. The first section describes the class of Markov state space models that are used to characterize a single SONET ring. The second section establishes the relationships between the failure modes of the ring and the intraring circuit paths that are affected by these failure modes. This section also develops some of the algebra for computing reliability statistics of interest to network performance. The third section accomplishes for interring circuit paths what the second section does for intraring circuits. The fourth section aggregates the relationships developed in the second and third sections to provide the formalism for computing circuit and network level reliability performance statistics.
Piracy continues to be a very real problem for ship operators, ship owners, cargo owners, insurance companies, flag states, and host states. Fortunately, the nature and locations of modern day acts of piracy tend to be fairly predictable and are concentrated in certain regions of the world. Potential acts of maritime terrorism are highly unpredictable and pose a worldwide threat since terrorists may attack a country's interests abroad. Commercial ship operators can take concrete steps to help defend themselves against maritime terrorism and piracy. Many ship self defense countermeasures against piracy and maritime terrorism are simple and inexpensive to implement. Developing a thorough ship security plan is essential for commercial ship self defense.
First responders are those elements of law enforcement, fire and rescue, emergency medical services, and national security personnel including military units who respond to emergency calls of service. In this paper, the maritime terrorist threat is introduced and an updated status of the U.S. government's response to the threat through organizational change is documented. Some of the more recent changes within the U.S. Coast Guard that affect the nation's posture against maritime terrorism are presented. A list of some of the first responders and supporting organizations to a maritime security incident is provided. A plausible incident scenario is used to illustrate the resulting flow of information and the need to rapidly disseminate data to the first responders to help them be both safe and effective.