bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unification of the Abridged Nautical Almanac and the American Nautical Almanac
Authors: Clemence G. M. , Sadler D. H. 
Published: January 2010

Announcement. As from the editions for the year 1958 the Abridged Nautical Almanac and the American Nautical Almanac will become identical in content, and will be reproduced from identical material, apart from the title pages and covers; they will for the time being retain their present titles, and will continue to be printed and published separately in the United Kingdom and the United States. The unified Almanac will be produced jointly by H.M. Nautical Almanac Office of the Royal Greenwich Observatory, Herstmonceux, and the Nautical Almanac Office of the U.S. Naval Observatory in Washington, to meet the general requirements for surface navigation in the two countries.Unification became a possibility with the decision to prepare copy for the Abridged Nautical Almanac on the card-controlled typewriter in H.M. Nautical Almanac Office; this machine is identical with that at the U.S. Naval Observatory, which has been used to prepare copy for the American Nautical Almanac since 1950. A large number of arrangements were tried for the daily pages, some with one day to the page or two days to the opening, and others with three days to the opening. The consensus of opinion in the United Kingdom favoured the latter form, which is already in use in the American Nautical Almanac. This opened the way to a detailed investigation into an arrangement that would prove acceptable to users and producers in both countries. The unified Almanac is the result of this collaboration.
A Modern View of Lunar Distances
Authors: Almanac Office H.M. Nautical 
Published: January 2010

In 1766 Nevil Maskelyne, fifth Astronomer Royal, compiled and published the first edition of The Nautical Almanac and Astronomical Ephemeris, designed to make practicable the determination of longitude at sea by the method of lunar distances. To mark the occasion of the two-hundredth anniversary of this event the staff of H.M. Nautical Almanac Office presents an objective assessment of the method of determining longitude by the measurement of lunar distances, in terms of modern knowledge, outlook, notation and computing facilities.Reference to contemporary publications has been deliberately avoided; the story of the development of methods and techniques for the observation and reduction of lunar distances requires, and deserves, a separate study.
Separation Standards—II
Authors: Reich P. G. 
Published: January 2010

In the first part of this series of papers an outline was given of the approach made at the Royal Aircraft Establishment to the problems of estimating collision risk and of specifying the quality of navigation needed to make separation standards safe. It was stressed that estimates should be based on intensive observation of flying errors, rather than on speculative theories, and that it is more feasible to develop ‘upper limit’ estimating techniques than those which purport to give the exact risk. In summary, a list of seven ‘requirements’ was given, as a reminder of the essential principles which can so easily be overlooked in the piecemeal task of relating separation standards to collision risk.The purpose of this paper is to show some of the theoretical techniques which have been developed at R.A.E. to satisfy five of these requirements. (The remaining two do not call for special techniques and will be dealt with when practical applications are described in Part III.) The paper contains three Appendixes, dealing with the frequency of losing separation in one dimension, the computation of P's from the assumed tail shapes, and the treatment of relative errors. These are not included here but will appear in the off-printed version which may be obtained from the Royal Aircraft Establishment.Both this paper and the paper that follows by Mr. Attwooll are crown copyright and are reproduced with the permission of H.M. Stationery Office.
Visual Direction Indication for Ships
Authors: Wepster A. 
Published: January 2010

Already many years ago Captain A. Vreugdenhil proposed the use of visual aids to supplement the sound signals used to indicate changes in heading. His idea of using visual aids was based on the erratic behaviour of sound and the consequent possibility of misinterpretation of sound signals.Choosing between two possible systems, the directional illuminated arrow and, for example, flashing lights, he preferred and constructed an illuminated arrow, visible as such from a distance of approximately 1½—2 miles. He was against the use of synchronous flashing lights, pointing out the large difference in speed of propagation between sound and light signals and consequent possibility of errors when different sound signals are given in quick succession.
Sight Reduction Tables for Marine Navigation
Authors: Blythe J. H. , Duncombe R. L. , Sadler D. H. 
Published: January 2010

The purpose of this article is to describe the new tables, with the above title, which are shortly to be published by the U.S. Naval Oceanographic Office as H.O. Pub. No. 229.Historical Survey. The most comprehensive tables designed for the application of the intercept method of plotting position lines in the practice of astronomical navigation at sea are the well-known Tables of Computed Altitude and Azimuth, originally published in the years 1936–1945 as H.O. Pub. No. 214 by the U.S. Navy Hydrographic Office (as it was then called). These are by no means the earliest of such tables in concept and objective, for Lord Kelvin, generally considered the father of modern navigation methods, expressed interest in tables from which solutions could be extracted direct; he recognized, however, that the tabulation of 903 × 603 or 157,464,000,000 solutions, which would be required to avoid interpolation, was quite impracticable.
Longitude without Time
Authors: Evans J. J. 
Published: January 2010

The problem of determining longitude without reference to a timepiece is one which even today commands the interest of a number of mathematicians, astronomers and navigators. Having recently undertaken a crossing of the Atlantic in a small boat, I was particularly interested in Mr. Chichester's article and Mr. Sadler's comments in the January edition of this Journal.The use of the visible horizon as a reference point for measuring the lunar distance from a celestial body is described in some of the older books on Nautical Astronomy. One method consists of observing the altitudes of the Moon and second body on opposite sides of the meridian and thence computing their respective hour angles. The sum of their hour angles is then equivalent to the difference in right ascensions of the two bodies. With this information, the lunar distance can readily be found and compared with tabulated or calculated lunar distances for given instants of G.M.T. to obtain the G.M.T. of observation. Mr. Chichester's variation of the method is certainly ingenious, and the need to compare lunar distances is thereby dispensed with. I cannot, however, see any reason why intervals as large as one hour between plots should be necessary: the overall size of the plot could well be reduced to one-sixth of the size, without loss of accuracy, by using times say 5 min. on each side of the ‘guessed at’ G.M.T.
Collision Regulations and the Courts
Authors: George B. D. G. 
Published: January 2010

The Rules for Navigation were established originally by custom and prudence some 400 years ago, but they were not presented in a codified form until 1863. Since then they have been modified several times, with the most recent modification becoming effective in September 1965.The Rules apply to all British ships, together with those belonging to signatory countries of the International Conference on Safety of Life at Sea, 1960. They apply also to all ships navigating within British territorial waters, but, in areas governed by local rules, they serve to supplement not to override those local rules.
Bad Language
Authors: Anderson E. W. 
Published: January 2010

SummaryExamples have been given of certain words which seem to be used correctly by navigators where there is any chance of ambiguity. It is suggested that, if these and other terms can be formally denned and agreed by the Institutes of Navigation, bad language will gradually die out and confusion in navigation terminology will be reduced to a minimum. A similar exercise might also be undertaken with regard to abbreviations.It may be that the British Institute of Navigation working with other English-speaking Institutes of Navigation could make a start by defining certain words in the hope that they will gradually come to be used with a specific meaning. The alternative is a continuation of the present chaos whereby an official body such as the Airlines Electronics Engineering Committee can decide that ‘course’ and ‘track’ have the same meaning and therefore that a direction is a line.This note is published with the kind permission of Mr. K. Fearnside, Technical Director of Smiths Aviation Division, but is not intended to represent Company views. Mr. M. W. Richey's advice and help is gratefully acknowledged.
The Exponential Integral Frequency Distribution
Authors: Parker J. B. 
Published: January 2010

In a recent note, D. A. Lloyd has obtained a formula for the frequency distribution of time dependent errors in terms of the exponential integralThis note clarifies Lloyd's derivations by referring to a theoretically identical, though conceptually different, time-independent, physical model, relates this distribution to one described by Anderson and concludes with a short appreciation of the role of the negative exponential distribution in navigational studies.
Marine Traffic Engineering
Authors: Toyoda Seiji , Fujii Yahei 
Published: January 2010

Marine traffic engineering is defined as the study of marine traffic and the application of such studies to improvements in navigation facilities and traffic regulation. The authors review recent Japanese work in this field.Since the mountainous terrain of Japan hindered the development of road transport, goods have mainly been sent by ship, from the earliest times until the end of the last century. The rapid economic recovery of Japan after the Second World War owes much to the industrial belt along the coast which may be called the ‘Water Megalopolis’, with more than 70 million inhabitants. Shipping provides the greater part of both interzonal and international transport and consequently there is severe traffic congestion, accentuated by the presence of more than 200,000 fishing vessels.
The Master in Changing Times
Authors: Buzek F. J. , Wepster A. 
Published: January 2010

The collision, in October 1970 in the English Channel, between the Liberian registered tankers Pacific Glory and Allegro may be thought to have brought an element of timeliness to the arguments advanced in this paper in favour of an international disciplinary court of justice and international standards for certificates of competency.Dr. Buzek is both a Master Mariner and a Doctor at Law; Captain Wepster, the Institute's gold medallist for 1970, is with the Holland America Line.In a speech before the seventh meeting of the Cultural Council of Europe, Dr. Mansholt expressed the opinion that in our highly industrialized western world, the time has arrived when environment is of equal importance with economy. On a world-wide scale we need general agreements on acceptable noise levels and pollution, with binding rules for industry, transport and agriculture as well as international control on the observance of these rules.
The Air Analogy at Sea
Authors: Van Hooff J. F. Drijfhout 
Published: January 2010

The recent spate of collisions and groundings in the Dover Strait and its approaches lend some urgency to Admiral Van Hooff's paper in which he calls for the introduction of traffic information in regions at sea where the traffic may be controlled by local authority after the fashion of air traffic control. The author was until recently Director-General of Pilotage and Aids to Navigation in the Netherlands Ministry of Defence.The number of voices that maintain that the conduct of ships about the sea, particularly when approaching ports or other focal areas, should be regimented in a similar way to aircraft when under Air Traffic Control, has been steadily on the increase.
Area Navigation
Authors: Robinson W. P. 
Published: January 2010

The following discussion took place at an open meeting of the Technical Committee, held at the Royal Aeronautical Society in London on 20 January 1971 with Mr. H. E. Smith in the Chair, the introductory discussion paper being presented by Mr. W. P. Robinson, Senior Navigation Superintendent of B.O.A.C.The interest in area navigation has been stimulated by the knowledge that in many areas of the world air traffic density is expected to exceed the capacity of the existing A.T.C. system in the foreseeable future. Nevertheless, it is important to realize that air traffic delays often result from a lack of airport capacity rather than deficiencies in the air traffic services. Airport capacity is a subject in itself; it is our task to examine how we can improve the present A.T.C. system by the use of area navigation.
Sea Pilotage Today: I—Remote Pilotage
Authors: Van Hooff Drijfhout 
Published: January 2010

The recent developments at the Gironde-estuary have aroused great interest and, particularly in ports where radar installations covering the approaches are in operation today, the question arises whether the adoption of some such scheme would be feasible and advantageous.Considerable experience with shore—based radar assistance had been gained over the years, but so far information only has been supplied and never advice. It was reasoned that only the men on the spot—master and pilot on the bridge—can decide what is to be done; advice from the shore, given without proper knowledge of what goes on on board, has been looked upon as dangerous.
The Alignment of Aircraft Navigation Sub-systems
Authors: Clifford P. H. R. 
Published: January 2010

Much attention has been given in the past to the need for aligning navigational systems in the horizontal and the vertical planes. The alignment problem has, in the main, been that of aligning inertial navigators or gyro platforms, but the problem also affects all navigation and attack equipment.In the past insufficient consideration has been given to the alignment of navigational sub-systems (including missile guidance systems) to the aircraft on which they are carried. The Experimental Navigation Division of the Aeroplane and Armament Experimental Establishment is investigating current methods of aligning equipments to aircraft with a view to improving them and recommending a future policy for the overall alignment of navigation and weapon systems, for service and civil aircraft.
The Long-range Navigation of Civil Aircraft
Authors: Hampton D. E. , Mills J. R. 
Published: January 2010

This paper, which was presented at an Ordinary Meeting of the Institute held in London on 15 November 1963, sets out to comment on certain aspects of the long-range navigation of civil aircraft. It concentrates on three areas where there seems to be room for improvement: reliability (a failure rate of 1 : 10 is suggested); the integration of navigation information into a single system and display; standardization of navigation facilities so that all aircraft can use the same basic system.It is concluded that a reliable system is required down to ground level, an indication of reliability should be presented to the pilot, that high reliabilities can be obtained by comparison of ground-based and self-contained aids, that a navigation computer is necessary to reduce the information to a presentable form, and that the use of very low frequencies seems to be the most promising way of developing an aid along these lines.
Congestion in Terminal Areas
Authors: Ratcliffe S. 
Published: January 2010

Terminal area A.T.C. must provide each aircraft with access to a network of different facilities. If these each treat their customers on a “first-come first-served” basis, congestion arises which could be avoided by more comprehensive planning. In a large busy terminal area it is at present necessary to decentralize the control process to avoid overloading the human controllers and it is then hard to avoid using “firstcome first-served”. This undesirable trend can be reversed if we hand over part of the decision-making process to an electronic computer.This paper will be presented for discussion at the Eastbourne tripartite conference, 12–14 May.
Radar Displays
Authors: Glasgow J. A. 
Published: January 2010

In a recent contribution to Forum by Commandant L. Oudet (Journal, 17, 88) the problem of the rational form that marine radar displays should take has been raised. The old argument of ‘ship's head upwards’ or ‘north upwards’ may be resolved by a combination of the best of both systems without compromise to either school of thought.Before starting on how this may be achieved a short digression on terminology should not be out of place. The advantages in the use of a ‘north upwards’ display, i.e. true bearings, lack of smear, accurate plotting and the ability to add ‘true motion’ do not stem fundamentally from the fact that north is at the top but because the picture is ‘compass stabilized’. The ‘north up’ condition is purely a matter of convenience. The ‘north upwards’ display would be better termed ‘compass stabilized north upwards’.
Ministry of Transport Examinations
Authors: Stephenson G. E. 
Published: January 2010

If the day is not far off when communication satellites will lessen a navigator's dependence on conventional astronomical aids it is surely overdue for the deletion of obsolescent and superfluous items from the M.O.T. syllabus for candidates.Of the three ‘standard’ formulae for finding a position line from an altitude of a celestial body (ex observer's meridian) only one, Marcq St. Hilaire, is in general use at sea today. The other two, Longitude by Chronometer and Latitude by Ex-meridian, depend for survival on the patronage of the Ministry of Transport and the Nautical Schools.
Grid Navigation
Authors: Garbasz J. 
Published: January 2010

The use of the Greenaway grid (curved) lines has enabled us to measure grid directions correctly on a Lambert chart (in middle latitudes). However, due to the fact that some charts are printed with only straight grid lines (such as the NAT 3071), a transport rate correction was devised which is supposed to combine both the correction for Earth rotation and the correction required because of the straight grid lines.Whilst the idea is an interesting one, a basic mistake is introduced which leads to serious errors in grid direction measurement.
Three-Dimensional Scanning Transmission Electron Microscopy of Biological Specimens
Authors: de Jonge Niels , Sougrat Rachid , Northan Brian M. , Pennycook Stephen J. 
Published: January 2010

AbstractA three-dimensional (3D) reconstruction of the cytoskeleton and a clathrin-coated pit in mammalian cells has been achieved from a focal-series of images recorded in an aberration-corrected scanning transmission electron microscope (STEM). The specimen was a metallic replica of the biological structure comprising Pt nanoparticles 2–3 nm in diameter, with a high stability under electron beam radiation. The 3D dataset was processed by an automated deconvolution procedure. The lateral resolution was 1.1 nm, set by pixel size. Particles differing by only 10 nm in vertical position were identified as separate objects with greater than 20% dip in contrast between them. We refer to this value as the axial resolution of the deconvolution or reconstruction, the ability to recognize two objects, which were unresolved in the original dataset. The resolution of the reconstruction is comparable to that achieved by tilt-series transmission electron microscopy. However, the focal-series method does not require mechanical tilting and is therefore much faster. 3D STEM images were also recorded of the Golgi ribbon in conventional thin sections containing 3T3 cells with a comparable axial resolution in the deconvolved dataset.
Cryomesh™: A New Substrate for Cryo-Electron Microscopy
Authors: Yoshioka Craig , Carragher Bridget , Potter Clinton S. 
Published: January 2010

AbstractHere we evaluate a new grid substrate developed by ProtoChips Inc. (Raleigh, NC) for cryo-transmission electron microscopy. The new grids are fabricated from doped silicon carbide using processes adapted from the semiconductor industry. A major motivating purpose in the development of these grids was to increase the low-temperature conductivity of the substrate, a characteristic that is thought to affect the appearance of beam-induced movement (BIM) in transmission electron microscope (TEM) images of biological specimens. BIM degrades the quality of data and is especially severe when frozen biological specimens are tilted in the microscope. Our results show that this new substrate does indeed have a significant impact on reducing the appearance and severity of beam-induced movement in TEM images of tilted cryo-preserved samples. Furthermore, while we have not been able to ascertain the exact causes underlying the BIM phenomenon, we have evidence that the rigidity and flatness of these grids may play a major role in its reduction. This improvement in the reliability of imaging at tilt has a significant impact on using data collection methods such as random conical tilt or orthogonal tilt reconstruction with cryo-preserved samples. Reduction in BIM also has the potential for improving the resolution of three-dimensional cryo-reconstructions in general.
Efficient local unfolding with ancestor stacks
Authors: PUEBLA GERMÁN , ALBERT ELVIRA , HERMENEGILDO MANUEL 
Published: January 2010

AbstractThe most successful unfolding rules used nowadays in the partial evaluation of logic programs are based on well quasi orders (wqo) applied over (covering) ancestors, i.e., a subsequence of the atoms selected during a derivation. Ancestor (sub)sequences are used to increase the specialization power of unfolding while still guaranteeing termination and also to reduce the number of atoms for which the wqo has to be checked. Unfortunately, maintaining the structure of the ancestor relation during unfolding introduces significant overhead. We propose an efficient, practical local unfolding rule based on the notion of covering ancestors which can be used in combination with a wqo and allows a stack-based implementation without losing any opportunities for specialization. Using our technique, certain nonleftmost unfoldings are allowed as long as local unfolding is performed, i.e., we cover depth-first strategies. To deal with practical programs, we propose assertion-based techniques which allow our approach to treat programs that include (Prolog) built-ins and external predicates in a very extensible manner, for the case of leftmost unfolding. Finally, we report on our implementation of these techniques embedded in a practical partial evaluator, which shows that our techniques, in addition to dealing with practical programs, are also significantly more efficient in time and somewhat more efficient in memory than traditional tree-based implementations.