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Constant Bearing, Decreasing Range
Constant bearing, decreasing range (CBDR) is a term in navigation which means that some object, usually another ship viewed from the deck or bridge of one's own ship, is getting closer but maintaining the same absolute bearing. If this continues, the objects will collide. Risk Sailors, especially deck hands and those who stand watch on the bridge, are trained to watch for this situation and make it known when they detect it happening. The reasoning is subtle: non-sailors who are used to driving automobiles normally are able to detect the possible risk of a collision with implicit reference to the background (e.g., the street, the scenery, the landscape, etc.) At sea, when vessels are borne in water, the sea surface removes this vital visual clue. Unaware individuals tend to gauge the risk of two vessels colliding based on which direction each vessel is heading. In other words, a novice will think that two vessels which appear to be heading apart from each other cannot collid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant Bearing, Decreasing Range
Constant bearing, decreasing range (CBDR) is a term in navigation which means that some object, usually another ship viewed from the deck or bridge of one's own ship, is getting closer but maintaining the same absolute bearing. If this continues, the objects will collide. Risk Sailors, especially deck hands and those who stand watch on the bridge, are trained to watch for this situation and make it known when they detect it happening. The reasoning is subtle: non-sailors who are used to driving automobiles normally are able to detect the possible risk of a collision with implicit reference to the background (e.g., the street, the scenery, the landscape, etc.) At sea, when vessels are borne in water, the sea surface removes this vital visual clue. Unaware individuals tend to gauge the risk of two vessels colliding based on which direction each vessel is heading. In other words, a novice will think that two vessels which appear to be heading apart from each other cannot collid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Is She Coming Our Way - Constant Bearing Decreasing Range
In linguistics, a copula (plural: copulas or copulae; abbreviated ) is a word or phrase that links the subject of a sentence to a subject complement, such as the word ''is'' in the sentence "The sky is blue" or the phrase ''was not being'' in the sentence "It was not being co-operative." The word ''copula'' derives from the Latin noun for a "link" or "tie" that connects two different things. A copula is often a verb or a verb-like word, though this is not universally the case. A verb that is a copula is sometimes called a copulative or copular verb. In English primary education grammar courses, a copula is often called a linking verb. In other languages, copulas show more resemblances to pronouns, as in Classical Chinese and Guarani, or may take the form of suffixes attached to a noun, as in Korean, Beja, and Inuit languages. Most languages have one main copula, although some (like Spanish, Portuguese and Thai) have more than one, while others have none. In the case of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigation
Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, and space navigation. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and direction. In this sense, navigation includes orienteering and pedestrian navigation. History In the European medieval period, navigation was considered part of the set of '' seven mechanical arts'', none of which were used for long voyages across open ocean. Polynesian navigation is probably the earliest form of open-ocean navigation; it was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity, and purpose. Ships have supported exploration, trade, warfare, migration, colonization, and science. After the 15th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to world population growth. Ship transport is responsible for the largest portion of world commerce. The word ''ship'' has meant, depending on the era and the context, either just a large vessel or specifically a ship-rigged sailing ship with three or more masts, each of which is square-rigged. As of 2016, there were more than 49,000 merchant ships, totaling almost 1.8 billion dead weight tons. Of these 28% were oil tankers, 43% were bulk carriers, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bearing (navigation)
In navigation, bearing or azimuth is the horizontal angle between the direction of an object and north or another object. The angle value can be specified in various angular units, such as degrees, mils, or grad. More specifically: * Absolute bearing refers to the angle between the magnetic north (''magnetic bearing'') or true north (''true bearing'') and an object. For example, an object to due east would have an absolute bearing of 90 degrees. Thus, it is the same as azimuth.U.S. Army, ''Advanced Map and Aerial Photograph Reading'', Headquarters, War Department, Washington, D.C. (17 September 1941), pp. 24-2/ref> * #Relative, Relative bearing refers to the angle between the craft's forward direction (heading) and the location of another object. For example, an object relative bearing of 0 degrees would be immediately in front; an object relative bearing 180 degrees would be behind. Bearings can be measured in mils, points, or degrees. Thus, it is the same as an ''azimuth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watchstanding
Watchkeeping or watchstanding is the assignment of sailors to specific roles on a ship to operate it continuously. These assignments, also known at sea as ''watches'', are constantly active as they are considered essential to the safe operation of the vessel and also allow the ship to respond to emergencies and other situations quickly. These watches are divided into work periods to ensure that the roles are always occupied at all times, while those members of the crew who are assigned to work during a watch are known as ''watchkeepers''. On a typical seafaring vessel, be it naval or merchant, personnel "keep a watch" in various locations and duties across the ship, such as the bridge and engine room. Typical bridge watchkeepers include a lookout and a deck officer who is responsible for the safe navigation of the ship; whereas in the engine room, an engine officer ensures that running machinery continues to operate within tolerances. Types of watches A wide variety of types of w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge (nautical)
The interior of the bridge of the Sikuliaq'', docked in Ketchikan, Alaska">RV_Sikuliaq.html" ;"title="Research Vessel ''RV Sikuliaq">Sikuliaq'', docked in Ketchikan, Alaska file:Wheelhouse of Leao Dos Mares.jpg, Wheelhouse on a tugboat, topped with a flying bridge The bridge, also known as the pilothouse or wheelhouse, is a room or platform of a ship from which the ship can be commanded. When a ship is under way, the bridge is manned by an officer of the watch aided usually by an able seaman acting as a lookout. During critical maneuvers the captain will be on the bridge, often supported by an officer of the watch, an able seaman on the wheel and sometimes a pilot, if required. History and etymology The compass platform of a British destroyer in the Battle of the Atlantic during the Second World War with central binnacle">Second_World_War.html" ;"title="Battle of the Atlantic during the Second World War">Battle of the Atlantic during the Second World War with central bin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Bearing
In navigation, bearing or azimuth is the horizontal angle between the direction of an object and north or another object. The angle value can be specified in various angular units, such as degrees, mils, or grad. More specifically: * Absolute bearing refers to the angle between the magnetic north (''magnetic bearing'') or true north (''true bearing'') and an object. For example, an object to due east would have an absolute bearing of 90 degrees. Thus, it is the same as azimuth.U.S. Army, ''Advanced Map and Aerial Photograph Reading'', Headquarters, War Department, Washington, D.C. (17 September 1941), pp. 24-2/ref> * #Relative, Relative bearing refers to the angle between the craft's forward direction ( heading) and the location of another object. For example, an object relative bearing of 0 degrees would be immediately in front; an object relative bearing 180 degrees would be behind. Bearings can be measured in mils, points, or degrees. Thus, it is the same as an ''azimuth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Bearing
In navigation, bearing or azimuth is the horizontal angle between the direction of an object and north or another object. The angle value can be specified in various angular units, such as degrees, mils, or grad. More specifically: * Absolute bearing refers to the angle between the magnetic north (''magnetic bearing'') or true north (''true bearing'') and an object. For example, an object to due east would have an absolute bearing of 90 degrees. Thus, it is the same as azimuth.U.S. Army, ''Advanced Map and Aerial Photograph Reading'', Headquarters, War Department, Washington, D.C. (17 September 1941), pp. 24-2/ref> * #Relative, Relative bearing refers to the angle between the craft's forward direction (heading) and the location of another object. For example, an object relative bearing of 0 degrees would be immediately in front; an object relative bearing 180 degrees would be behind. Bearings can be measured in mils, points, or degrees. Thus, it is the same as an ''azimut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starboard
Port and starboard are nautical terms for watercraft and aircraft, referring respectively to the left and right sides of the vessel, when aboard and facing the bow (front). Vessels with bilateral symmetry have left and right halves which are mirror images of each other. One asymmetric feature is where access to a boat, ship, or aircraft is at the side, it is usually only on the port side (hence the name). Side Port and starboard unambiguously refer to the left and right side of the vessel, not the observer. That is, the port side of the vessel always refers to the same portion of the vessel's structure, and does not depend on which way the observer is facing. The port side is the side of the vessel which is to the left of an observer aboard the vessel and , that is, facing forward towards the direction the vehicle is heading when underway, and starboard side is to the right of such an observer. This convention allows orders and information to be given unambiguously, witho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Road Safety
Road traffic safety refers to the methods and measures used to prevent road users from being killed or seriously injured. Typical road users include pedestrians, cyclists, motorists, vehicle passengers, horse riders, and passengers of on-road public transport (mainly buses and trams). Best practices in modern road safety strategy: As sustainable solutions for classes of road safety have not been identified, particularly low-traffic rural and remote roads, a hierarchy of control should be applied, similar to classifications used to improve occupational safety and health. At the highest level is sustainable prevention of serious injury and death crashes, with sustainable requiring all key result areas to be considered. At the second level is real-time risk reduction, which involves providing users at severe risk with a specific warning to enable them to take mitigating action. The third level is about reducing the crash risk which involves applying the road-design standards a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Flow
Optical flow or optic flow is the pattern of apparent motion of objects, surfaces, and edges in a visual scene caused by the relative motion between an observer and a scene. Optical flow can also be defined as the distribution of apparent velocities of movement of brightness pattern in an image. The concept of optical flow was introduced by the American psychologist James J. Gibson in the 1940s to describe the visual stimulus provided to animals moving through the world. Gibson stressed the importance of optic flow for affordance perception, the ability to discern possibilities for action within the environment. Followers of Gibson and his ecological approach to psychology have further demonstrated the role of the optical flow stimulus for the perception of movement by the observer in the world; perception of the shape, distance and movement of objects in the world; and the control of locomotion. The term optical flow is also used by roboticists, encompassing related techniq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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