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The Off-The-Shelf System (OTSS) is a packaged information management system for hierarchical data bases. OTSS provides, without computer programming, processes to enter and alter data in such a data base, do complex retrievals of data from the data base, and specify various security mechanisms to limit access to, or alteration of, a data base. OTSS also provides a mechanism for extending the available processes on a project-by-project basis. OTSS has been implemented using MASTER LINKS and the NATURAL DIALOGUE SYSTEM.

Summary A geophysical well logging equipment is described which is suitable for hydrogeological investigations in aquifers found in the British Isles. The electronic equipment used is available “off the shelf” commercially and although not designed for borehole logging has been found to be ideal for this purpose. The logging sondes, cable drums, and other borehole equipment are now available to order from a British company.

A strapdown system is considered as an unaided inertial navigator aboard an aircraft. Presented here are simulation results detailing the propagation of navigation errors (in nautical miles) due to strapdown sensor errors for four trajectories. They indicate the type of performance that can be expected from a strapdown system utilizing good ?off the shelf? gyros and accelerometers, and dramatically illustrate the improvements necessary in these components to obtain navigation performance comparable to that available from a good gimballed inertial system. The total navigation error for each trajectory is broken down to show the contribution from each of the various error sources. This breakdown quickly reveals which are the critical error sources for a given trajectory class, and also points up the relationship that exists between each individual error source, aircraft maneuvers, and the resulting navigation error. Several of the error mechanisms are discussed at length and a set of linearized differential equations which can be used to analyze error propagations is presented. These results should be of particular interest to the system designer who is faced with the problem of specifying the sensor error parameters necessary to meet mission performance requirements. With an analysis similar to the one presented here, but structured around his own expected mission trajectories, the designer should be able to confidently predict system accuracies and intelligently perform tradeoffs on the critical system parameters.

More often than not, designers must use off-the-shelf components in creating a new equipment design. This is especially true when components relate to maintenance. Because much of this type of hardware is hidden from view, or is not considered part of the operating interface, components related to maintenance often are not selected with proper attention to human engineering considerations, either by the designer or the human engineer. Experience has shown that although many human engineering specialists specify general maintenance criteria, they do not follow through in selection of individual components that may be purchased off the shelf. This paper discusses typical design problems and recommends that human engineers take steps to keep up to date on new products, so that they will be in a better position to recommend those products which are better human-engineered.

Too often, engineers spend a great deal of time worrying about the sophisticated technical parameters of their problems but forget or ignore the equally important non-technical factors that will determine whether their innovations will ever get off the shelf and into the marketplace. Yet we all know that the continued success and viability of the engineering profession is sensitively dependent on our ability to cycle innovations into profits.

As the hitherto anonymous reviser who prepared the current G.H.A. edition of Martelli's Tables, was interested, instructed and surprised by Captain Cotter's article in the Forum on this subject. I was surprised that he should write of them as if they were things of the past. In fact they are available off the shelf at my local chart agents, and no doubt elsewhere, so a demand presumably exists today, and they are in current use. From some of the comments which he makes, and the extract from Table 5 which he reproduces, it appears that he has not seen the current edition.

Studies have been conducted on a group of candidate materials and structural concepts applicable to refurbishable composite ablative thermostructural heat shield panel configurations for manned lifting entry vehicles. Although some relatively advanced material concepts were briefly considered, only off the shelf materials with overall state of the art capability were selected. Practical design implications associated with the use of refurbishable heat shield panel concepts, such as panel size constraints, configuration of joints, substrate panel support interactions, heat short effects associated with the panel support system, and fabrication and cost aspects, have been evaluated and integrated into the selection of a recommended thermostructural panel configuration.

THERE is a large number of different laryngeal sprays available, and the excuse for adding to this list is that the sprays I am now using are more satisfactory than others I have tried. Nebulizers which are complicated in design, and contain metal capillary tubes, suffer from the defect that unless they are washed clean after each occasional use— a costly matter, and troublesome—they soon become attacked by the alkaloid used as analgesic. Crystals deposit, and when the spray is taken off the shelf for use in a hurry it either blows nothing but air or delivers large and dangerous drops into the pharynx. The Rogers all-glass spray does not react in any way with the analgesic solution. It can be placed on the shelf after use and taken down again weeks later, and will immediately deliver a fine spray with no large drops. This spray, moreover, extends for about a yard from the nozzle, and can easily be operated with one hand. There is therefore no need to thrust any part of the spray into the pharynx, a procedure which is all too often the cause of movement of the laryngoscope and the elicitation of unsuppressed pharyngeal reflexes. The angle of the nozzle on the stem o" the Rogers spray is about 120°. It is possible that when it is used with the patient supine, with the laryngoscope in position for direct spraying of the cords, the reservoir may be higher than the nozzle, and fluid may run down into the pharynx. Messrs. Thackray of Leeds have kindly made for me some sprays with an angle of 90°. These sprays do not deliver liquid analgesic drops in any of the positions in which they are likely to be used in normal practice.

An avalanche pulsing circuit, constructed with off the shelf components operates reliably at 4.2 K. Nanosecond pulses with amperes of peak current are delivered to low impedance loads. Physical proximity of generator and load eliminate cross talk and transmission line distortion.

Locke and Schally and four associate authors from Tulane University School of Medicine have written a book that they hope will span the gap between research-oriented physiologists and anatomists on the one hand, and practicing clinicians (including neurosurgeons) on the other. This is certainly an ambitious undertaking and, if we fault them for not reaching their goal entirely, perhaps it is because they have set their goal so high. In general, this book will be most profitable as a reference source for most readers. The authors have gathered a stupendous amount of English literature citations regarding their topic, and the good index will probably mean that this book will frequently come off the shelf to settle some neuroendocrinologic dispute or to help in understanding some puzzling case. There are some problems that came up while reading this book. Certain sections are intellectually "thin" and out of date already (eg, the

NOT SINCE THE PUBLICATION of R. G. Collingwood's Idea of History has a work of "theory'' won from historians the amount of interest recently accorded Thomas S. Kuhn's The Structure of Scientific Revolutions.' If historians are conventionally aloof from philosophy of history, they are even less attentive to philosophy of science-yet contemporary footnotes prove that Kuhn's theory of science speaks to, and for, historians asi few works of philosophy of history ever have. Even the revered Collingwood, for all his influence upon intellectual historians during the 1940S and 1950S, served to stop discussions as often as to advance them; a citation to Collingwood's profound but forbidding "Epilegomena"2 enabled historians to perform an act of calm defiance: "we historians are on to something basic and complicated about human experience, which you can read about in Collingwood, and if you can't understand what he says, well, that's your problem." This defiant use of Collingwood may have been appropriate in some cases, and Collingwood will presumably continue to serve historians in this way without coming down off the shelf he now shares with a more mobile junior partner. Kuhn, unlike Collingwood, is being read carefully by many practicing historians. Not since the time of Charles Beard has any guild historian attracted an audience among the academic intelligentsia as extensive as Kuhn's. Collingwood, too, was a historian, but he always remained the peculiar possession of historians and of a handful of philosophers; The Structure of Scientific Revolutions has become a major text for interdisciplinary discourse and has been acclaimed by the cognoscenti that reads Levi