Presupposition failure — A comedy of errors

Presuppositions of utterances are the pieces of information you convey with an utterance no matter whether your utterance is true or not. We first study presupposition in a very simple framework of updating propositional information, with examples of how presuppositions of complex propositional updates can be calculated. Next we move on to presuppositions and quantification, in the context of a dynamic version of predicate logic, suitably modified to allow for presupposition failure. In both the propositional and the quantificational case, presupposition failure can be viewed as error abortion of procedures. Thus, a dynamic assertion logic which describes the preconditions for error abortion is the suitable tool for analysing presupposition.     

Robust crossfeed design for hovering rotorcraft

Control law design for rotorcraft fly-by-wire systems normally attempts to decouple the angular responses using fixed-gain crossfeeds. This approach can lead to poor decoupling over the frequency range of pilot inputs and increase the load on the feedback loops. In order to improve the decoupling performance, dynamic crossfeeds should be adopted. Moreover, because of the large changes that occur in the aircraft dynamics due to small changes about the nominal design condition, especially for near-hovering flight, the crossfeed design must be ‘robust’. A new low-order matching method is presented here to design robust crossfeed compensators for multi-input, multi-output (MIMO) systems. The technique minimizes cross-coupling given an anticipated set of parameter variations for the range of flight conditions of concern. Results are presented in this paper of an analysis of the pitch/roll coupling of the UH-60 Black Hawk helicopter in near-hovering flight. A robust crossfeed is designed that shows significant improvement in decoupling perfomance and robustness over the fixed-gain or single point dynamic compensators. The design method and results are presented in an easily used graphical format that lends significant physical insight to the design procedure. This plant precompensation technique is an appropriate preliminary step to the design of robust feedback control laws for rotorcraft.     

Review of Elements of episodic memory.

Reviews the book, Elements of episodic memory by Endel Tulving (1983). Those of us who have followed Tulving's investigations in the somewhat fragmented form of journal articles are very grateful to have his ideas encapsulated, elaborated, and elegantly expounded in his Elements of episodic memory. Tulving spends the initial third of the book driving home the evidence that the distinction between episodic and semantic memory is not just that episodic is time-lagged and semantic is not: it is more far-ranging, and his new work on amnesia is leading to the conclusion that for some forms of this disorder either type of memory may be attacked but not necessarily both. The first vista that opens from Tulving's vantage point is that "systems" and "schemata" are collections of connections that derive a certain autonomy from being only loosely connected to other collections. The second vista that emerges is a psychology in which the use of numbers is rich and strange. A third vista that opens up is shielded at first by a spectre of opposition. The spectre seizes on the passage on "free radicals," in which Tulving claims that certain thoughts cannot be unambiguously assigned to either episodic or semantic memory. Perhaps the most heartening aspect of this book is that Tulving could never have written this monograph without the foundations of his experiments. It is a great relief to see experimentation validated in so invigorating a form. Nevertheless, the most difficult chapters of the book, on recognition and recall, are built on experimental findings that are not yet properly understood. I am glad Tulving did not delay in writing this book until he felt more secure about the questions raised in these last chapters: the work thereby remains a challenge rather than a fait accompli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Soft-spring nonlinear vibrations of antisymmetrically laminated rectangular plates

This paper deals with the effects of initial geometric imperfections and in-plane boundary conditions on the large-amplitude vibration behavior of angle- and cross-ply rectangular thin plates. It is found that the presence of imperfection amplitudes of the order of only half the total laminated-plate thickness may significantly raise the vibration frequencies and change the large-amplitude vibration behavior from the well-known hard-spring to soft-spring behavior. The effects of fibre angles and bending-stretching coupling for angle-ply plates and Young's moduli ratios and number of layers for antisymmetric cross-ply plates are examined.     

Replacement of beef fat in Frankfurters by interesterified palm,cottonseed and olive oils

Three interesterified vegetable oils (IVOs) prepared from palm, cottonseed, and olive oil, respectively, have been studied for application to Frankfurters. Beef fat (10%) was replaced by one of the IVOs at 20, 60 or 100%. Fatty acid composition of the lipid fraction in the Frankfurters and saturated/unsaturated ratios were established for all batches. We found that total or partial replacement of beef fat by IVOs did not lead to significant changes in appearance, colour, texture, flavour or sensory score. We conclude that IVOs may be successfully applied as beef fat substitutes in Frankfurters.