Rethinking the Patch Test for Phase Measuring Bathymetric Sonars

While conducting hydrographic survey operations in the Florida Keys, NOAA Ship Thomas Jefferson served as a test platform for the initial operational implementation of an L-3 Klein HydroChart 5000 Swath Bathymetry Sonar System1 , a hull-mounted phase measuring bathymetric sonar (PMBS). During the project it became apparent that the traditional patch test typically utilized for multibeam echosounder (MBES) systems was poorly suited to the HydroChart – and perhaps other PMBS systems as well. These systems have several inherent characteristics that make it difficult to isolate and subsequently solve for biases under the traditional patch test paradigm: presence of a nadir gap, wide swaths (typically greater than 6 times water depth), and relatively poor object-detection capability in the outer swath. After “rethinking” the patch test to account for these characteristics, the authors propose a new patch test paradigm that is better suited to the HydroChart and other PMBS systems

United States Of America

Nearly 50 years ago, Schon (1971) urged universities to become aware of life ‘beyond the stable state’ and Toffler (1970) predicted that the information age would force academia to accommodate an ‘accelerating pace of change.’ Their prescient observations about the future have characterized American higher education for nearly 50 years, perhaps best exemplified by the role distance education (DE) has played in this process. DE’s remarkable progression in the US arena began well before the electronic era, extending over a 225-year period. It is a phenomenon that perhaps represents the most significant transformation within academe in a millennium, presenting exciting opportunities and formidable challenges. This chapter offers a descriptive analysis and commentary of key aspects of DE at the post-secondary level in the US, with perspectives gained from the author’s 35 years of scholarship and practice in the field

Optimizing Sound Speed Profiling for Hydrographic Surveys

The IHO Standards for Hydrographic Surveys (S-44) requires that hydrographic surveys account for sound speed uncertainties in order to determine the Total Propagated Uncertainty. If variations in sound speed are significant, the horizontal and vertical position of a sounding can vary by as much as several meters. Refraction artefacts can be typically dealt with in post-processing. This can be time consuming and require specialized processing expertise, especially in area of significant bathymetric relief and/or environmental variations in the water column. In this paper, we examine the application of recent advances in refraction based uncertainty to the ODIM Moving Vessel Profiler (MVP) controller software in order to optimize sound speed profiling operations.Las Normas de la OHI para Levantamientos Hidrográficos (S-44) requiere que los levantamientos hidrográficos tengan en cuenta la cuenta la incertidumbre sobre la velocidad del sonido con el objeto de determinar la Incertidumbre Total Propagada. Si las variaciones en la velocidad del sonido son significativas, la posición horizontal y vertical de una sonda puede variar tanto como varios metros. Típicamente se puede considerar los elementos refractarios durante el post procesado. Esto puede tomar tiempo y requerir experiencia especializada en procesamiento, especialmente en áreas de relieve batimétrico significativo y/o variaciones ambientales en la columna de agua. En este trabajo examinamos la aplicación de recientes progresos en la determinación de las incertidumbres basado en la refracción con el software de control del Perfilador del Movimiento de la Nave ODIM (MVP) con el objeto de optimizar las operaciones de perfilar la velocidad del sonido.Les normes de l’OHI pour les levés hydrographiques (S-44) exigent que les levés hydrographiques tiennent compte des incertitudes liées à la vitesse du son afin de déterminer l’incertitude totale propagée. Si les variations de la vitesse du son sont importantes, la position horizontale et verticale d’une sonde peut subir des variations de l’ordre de plusieurs mètres. D’une manière générale, les éléments de réfraction peuvent être pris en compte dans le cadre du post-traitement. Ceci peut prendre un certain temps et requiert des compétences spécialisées dans le traitement, notamment pour un relief bathymétrique significatif et/ou pour des variations environnementales dans la colonne d’eau. Dans cet article, nous examinons l’application des dernières avancées en matière d’incertitude basée sur la réfraction, au logiciel MVP (enregistreur de profils à partir d’un navire en mouvement) d’ODIM afin d’optimiser les opérations de détermination des profils de la vitesse du son

Lawyers and Sawyers: Venetian Forest Law and the Conquest of Terraferma (1350-1476)

Throughout the fourteenth and fifteenth centuries, Venice played a direct role in shaping the future of Northeastern Italy. The standing scholarship views Venetian involvement on the mainland as either an abandonment of the city’s maritime tradition or as a buffer zone against rival powers, like Milan. Venice’s western mainland empire, Terraferma, provided Venice with many commercial products that the Eastern Mediterranean did not. One mainland product, timber, was a central focus of Venetian expansion into Terraferma and has thus far been neglected by historians. This thesis argues that the Venetian Republic manipulated mainland legal traditions in order to obtain direct control over the forest resources of Terraferma. The pressures placed upon Venice by timber shortages and rival powers in the fourteenth and fifteenth centuries instigated a departure from Venice’s passive management of mainland cities and encouraged the city to strengthen its defenses through territorial expansion and forest conservation policies. Timber acquired from Terraferma was one of the vital sinews that bound the Venetian military and mercantile machine together. In order to directly control the mainland’s timber resources, the Venetians inserted their usufructory claims into the legal traditions of mainland communities. Archival sources and primary histories illustrate that Venetian forest policy evolved from cordial requests for timber into legal statutes that controlled local communities’ access to timber stands. The fall of Constantinople in 1453 and Negroponte in 1471 opened a window of opportunity, into which the Venetians inserted the mainland legal concept of “right to reserve,” diritto di reserva, in order expand and formalize their legal claims to Terraferma common forestland. The promulgation of six forest laws in 1476 punctuated the development of Venetian forest law in the fifteenth century. The laws governed the usage of forest resources and placed the Venetians in direct control of all of Terraferma’s community forests. The Venetians answered the question “Who owns the forest?” through the development of forest laws that placed timber ownership directly with a centralized government. The question easily expands into “Who owns the land, and all of its natural resources?” American natural resource managers and NGO’s continue to develop the American answer to the question. The Venetian forest narrative provides us with one possible answer to the question that elicits further conversations. Understanding Venice’s domination of mainland cities for ship-timber may also elicit further insight into how and why modern states dominate their neighbors for natural resources

Simulation levels of detail for plant motion

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 28-30).In this paper we describe a method for simulating motion of realistically complex plants interactively. We use a precomputation stage to generate the plant structure, along with a set of simulation levels of detail. The levels of detail are made by continuously grouping branches starting from the tips of the branches and working toward the trunk. Grouped branches are simulated as single branches that have similar simulation characteristics to the original branches. During run-time, we traverse the plant and determine the allowable error in the simulation of branch motion. This allows us to choose the appropriate simulation level of detail and we provide smooth transitions from level to level. Our level of detail approach affects only the simulation parameters, allowing geometry to be handled independently. Using this method we can significantly improve simulation times for complex trees

F.A.R.O.G. FORUM, Vol. 3 No. 5

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