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THE necessary manoeuvres of fighting aeroplanes in the present war may occasionally be expected to stress them beyond their strength. In addition to this, the increase in speed may be expected to produce unpleasant vibration. It is interesting, therefore, to consider how recent flutter investigations have influenced aeroplane design, and it is proposed in this article to review the more practical aspect of flutter research and to give a general guide to designers as to the importance of the many parameters influencing flutter speed.

IN the 1940 Wilbur Wright memorial lecture on the future of British Civil Aviation Dr. Roxbec Cox has stated that the study of passenger convenience leads to consideration of over weather flying and that the study of improvements in safety leads to consideration of flutter prevention. He has stated also that all aviation authorities recognize the danger of flutter and warns that the chief danger to be guarded against in the future is a sense of security. It has, therefore, been thought worth while to examine the effect on wing flutter speed of flying at great heights. The effects have already been briefly considered by Williams, Pugsley and Duncan in this country and by Kassner and Fingado in Germany.

THE stiffness of an aeroplane wing is usually considered in terms of its torsional and llexural stiffnesses as measured at the “mid‐aileron” and “equivalent tip” sections(1), (2). It appears at present that the stiffness in torsion is more significant than that in flexure, partly because high torsional stiffness is necessary to prevent not only flutter but also reversal of aileron control and divergence(1), (2), both of which are independent of llexural stiff‐ness ; and partly because it is found in practice that when a wing is designed to meet minimum existing strength requirements alone, its torsional stiffness may be inadequate whereas its llexural stiffness is commonly sufficient. The more important of the two torsional stiff‐nesses (“mid‐aileron” and “equivalent‐tip”) is that at the “mid‐aileron” section. The present paper examines the effect of the various parameters on the torsional stiffness of a tapered rectangular tube of proportions representative of an aeroplane wing under a con‐centrated torque applied at a section equivalent to the average “mid‐aileron” section. The analysis of the problem is based on the stress distribution in an axially constrained tapered tube given by Williams in R. & M. 1761(3), and the stiffness obtained is compared with that for a tube with the simple shear stress distribution of the Bredt‐Batho type for a tube with free ends. The similar problem for a uniform tube has already been solved from the equations of reference (3) in R. & M. 1790(4).

At the annual general meeting of British Messier Ltd., held on July 24, 1953, it was announced that the Rt. Hon. The Lord Hives, C.H., M.B.E., D.Sc., had tendered his resignation from the Board to take effect from that date. Mr W. T. Gill has consented to fill the vacancy caused by the resignation of Lord Hives. The British Messier Board now consists of the following: Sir W. Reginald Vcrdon Smith, Mr W. T. Gill, Lt.‐Gen. Sir John Evctts, Mr L. S. Armandias, Mr H. G. Conway.

IN the past, the required amount of directional stability was dictated mainly by asymmetric power considerations and by the maximum angles of sideslip in manoeuvres permissible from the structural strength viewpoint. The requirement for satisfactory recovery from steady spin would in certain cases influence both the directional stability and control power in such a fashion as ultimately to be the determining factor. Present indications are that the choice of the required degree of directional stability will be based on supersonic lateral dynamic stability considerations, in particular the stability of the so‐called Dutch roll oscillation, or on considerations of avoiding inertia coupling between the lateral and longitudinal degrees of freedom during rolling. Both of these problems will be discussed in some detail later. It should be emphasized, however, that large values of subsonic directional stability will be required for supersonic aircraft in order to provide satisfactory dynamic characteristics at supersonic speeds at high altitudes.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics and publications of other similar research bodies as issued

Multiple classifier systems have been used widely in computing, communications, and informatics. Combining multiple classifier systems (MCS) has been shown to outperform a single classifier system. It has been demonstrated that improvement in ensemble performance depends on either the diversity among or the performance of individual systems. A variety of diversity measures and ensemble methods have been proposed and studied. However, it remains a challenging problem to estimate the ensemble performance in terms of the performance of and the diversity among individual systems. The purpose of this paper is to study the general problem of estimating ensemble performance for various combination methods using the concept of a performance distribution pattern (PDP).

In particular, the paper establishes upper and lower bounds for majority voting ensemble performance with disagreement diversity measure Dis, weighted majority voting performance in terms of weighted average performance and weighted disagreement diversity, and plurality voting ensemble performance with entropy diversity measure D.

Bounds for these three cases are shown to be tight using the PDP for the input set.

As a consequence of the authors' previous results on diversity equivalence, the results of majority voting ensemble performance can be extended to several other diversity measures. Moreover, the paper showed in the case of majority voting ensemble performance that when the average of individual systems performance P is big enough, the ensemble performance P^m resulting from a maximum (information‐theoretic) entropy PDP is an increasing function with respect to the disagreement diversity Dis. Eight experiments using data sets from various application domains are conducted to demonstrate the complexity, richness, and diverseness of the problem in estimating the ensemble performance.

This study aims to improve the reliability of emergency safety barriers by using the subjective safety analysis based on evidential reasoning theory in order to develop on a framework for optimizing the reliability of emergency safety barriers.

The emergency event tree analysis is combined with an interval type-2 fuzzy-set and analytic hierarchy process (AHP) method. In order to the quantitative data is not available, this study based on interval type2 fuzzy set theory, trapezoidal fuzzy numbers describe the expert's imprecise uncertainty about the fuzzy failure probability of emergency safety barriers related to the liquefied petroleum gas storage prevent. Fuzzy fault tree analysis and fuzzy ordered weighted average aggregation are used to address uncertainties in emergency safety barrier reliability assessment. In addition, a critical analysis and some corrective actions are suggested to identify weak points in emergency safety barriers. Therefore, a framework decisions are proposed to optimize and improve safety barrier reliability. Decision-making in this framework uses evidential reasoning theory to identify corrective actions that can optimize reliability based on subjective safety analysis.

A real case study of a liquefied petroleum gas storage in Algeria is presented to demonstrate the effectiveness of the proposed methodology. The results show that the proposed methodology provides the possibility to evaluate the values of the fuzzy failure probability of emergency safety barriers. In addition, the fuzzy failure probabilities using the fuzzy type-2 AHP method are the most reliable and accurate. As a result, the improved fault tree analysis can estimate uncertain expert opinion weights, identify and evaluate failure probability values for critical basic event. Therefore, suggestions for corrective measures to reduce the failure probability of the fire-fighting system are provided. The obtained results show that of the ten proposed corrective actions, the corrective action “use of periodic maintenance tests” prioritizes reliability, optimization and improvement of safety procedures.

This study helps to determine the safest and most reliable corrective measures to improve the reliability of safety barriers. In addition, it also helps to protect people inside and outside the company from all kinds of major industrial accidents. Among the limitations of this study is that the cost of corrective actions is not taken into account.

Our contribution is to propose an integrated approach that uses interval type-2 fuzzy sets and AHP method and emergency event tree analysis to handle uncertainty in the failure probability assessment of emergency safety barriers. In addition, the integration of fault tree analysis and fuzzy ordered averaging aggregation helps to improve the reliability of the fire-fighting system and optimize the corrective actions that can improve the safety practices in liquefied petroleum gas storage tanks.

States that firms in many industries are seeking strategic partnerships with suppliers, distributors and customers. Discusses Customer‐Linked Strategy (CLS), a type of partnership being used by some firms. Evaluates the advantages and disadvantages of CLS and specifies appropriate circumstances for adopting CLS, together with information on implementing the partnership. Considers the consequencesof CLS and finds that it is of great benefit to many firms. Recommends that those businesses not currently using the technique but whose situation is suited to the strategy should reconsider their action.

How do managers, in their role as decision makers, design and implement systems for management of quality? Proposes that there is no one, definitive answer to this question, given various industrial environments and their operating constraints, diverse market conditions and numerous management philosophies. Attempts to address quality management issues in the business‐to‐business industrial service industry by presenting a case study on the quality management approach taken by Diamond Offshore Drilling, Inc. ‐ one of the largest offshore oil‐drilling companies in the world. States that the business‐to‐business industrial service markets are characterized by the sale of industrial services to business customers, who often then use these services to produce goods or services for consumers or other businesses. A wide variety of services are provided by the companies operating in this industry, such as offshore oil‐drilling and exploration, warehousing and public utilities. The case study follows the backdrop, initiation and complete implementation of Diamond Offshore’s Global Excellence in Management Systems (GEMS) programme. GEMS can be characterized as a system deeply rooted in the basics of quality management ‐ customer‐defined requirements and quality through customer satisfaction. Also discusses post‐implementation customer feedback results to illustrate the success of the programme. Based on the GEMS framework and relevant literature, proposes a generalized framework for implementing quality management in firms operating in business‐to‐business industrial service markets.