Ship Seakeeping Operability, Motion Control, and Autonomy - A Bayesian Perspective

Ship seakeeping operability refers to the quantification of motion performance in waves relative to mission requirements. This is used to make decisions about preferred vessel designs, but it can also be used as comprehensive assessment of the benefits of ship-motion-control systems. Traditionally, operability computation aggregates statistics of motion computed over over the envelope of likely environmental conditions in order to determine a coefficient in the range from 0 to 1 called operability. When used for assessment of motion-control systems, the increase of operability is taken as the key performance indicator. The operability coefficient is often given the interpretation of the percentage of time operable. This paper considers an alternative probabilistic approach to this traditional computation of operability. It characterises operability not as a number to which a frequency interpretation is attached, but as a hypothesis that a vessel will attain the desired performance in one mission considering the envelope of likely operational conditions. This enables the use of Bayesian theory to compute the probability of that this hypothesis is true conditional on data from simulations. Thus, the metric considered is the probability of operability. This formulation not only adheres to recent developments in reliability and risk analysis, but also allows incorporating into the analysis more accurate descriptions of ship-motion-control systems since the analysis is not limited to linear ship responses in the frequency domain. The paper also discusses an extension of the approach to the case of assessment of increased levels of autonomy for unmanned marine craft.

The physiological and behavioral responses of steers to gaseous ammonia in simulated long distance transport by ship.

Ammonia (NH3) can accumulate in high density cattle accommodation during live export shipments and could potentially threaten the animals' health and welfare. The effects of 4 NH3 concentrations, control (<8), 15, 30, and 45 ppm, on the physiology and behavior of steers were recorded. The animals were held for 12 d under a micro-climate and stocking density similar to shipboard conditions experienced on voyages from Australia to the Middle East during the northern hemispheric summer. In bronchoalveolar lavage samples, ammonia increased (P < 0.05) macrophage activity in proportion to NH3 concentration and it increased (P < 0.05) neutrophil percentage at 30 and 45 ppm, indicating active pulmonary inflammation. It also increased (P < 0.05) lacrimation, nasal secretions and coughing, particularly at 45 ppm, indicating that the NH3 was irritating the mucous membranes of the eyes, nasal cavity and respiratory tract. Ammonia had no effect (P > 0.05) on hematological parameters or body weight. Twenty-eight days after exposure to NH3, the steers' pulmonary macrophage activity and neutrophil levels had returned to normal. It was concluded that ammonia concentrations of 30 and 45 ppm induced temporary inflammatory responses which indicate an adverse effect on the welfare of steers.

Walter Gottschalk and Fritz Gottschalk (Papa) saying goodbye to Elizabeth and Hans Krakauer who are on board the ship Koenigstein leaving to emigrate to America; Antwerp, Belgium.

Digital Image

Albert Einstein; Princeton, New Jersey Portraits; Men

Digital Image

Albert Einstein; Princeton, New Jersey Portraits; Men

Digital Image

Albert Einstein; Princeton, New Jersey Portraits; Men

Digital Image

Albert Einstein "The Giant"; New Jersey Portraits; Men

"Der Riese"

Albert Einstein; Princeton, New Jersey Portraits; Men

Digital Image

Albert Einstein playing the violin with small orchestra; Princeton, New Jersey Portraits Men

Digital Image

Albert Einstein with David Ben Gurion; Princeton, New Jersey Portraits; Groups; Men

Digital Image

Albert Einstein with David Ben Gurion and unidentified man; Princeton, New Jersey Portraits; Groups; Men

Digital Image

Albert Einstein during naturalization oath ceremony for United States citizenship; Trenton, New Jersey Portraits Groups

Digital Image

Unidentified man, Elizabeth Krakauer nee Gottschalk and Hans Krakauer on board the ship Koenigstein traveling from Antwerp to New York City on their emigration voyage from Germany.

Digital Image

Herman Sommerfeld with unidentifed men and women on board a ship from Tallin to Helsinki (and on to the United States) Portraits Groups

Digital Image

Rose Wergert nee Herz on deck of the ship New York.

Rose, sister of Fred and Beatrice Herz