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Technologies that allow accurate measurement of rotorblade dynamics can impact almost all areas of the rotorcraft sector; ranging from maintenance all the way to blade design. The BladeSense project initiated in 2016 aims to take a step in developing and demonstrating such a capability using novel fibre optic sensors that allow direct shape measurement. In this article the authors summarise key project activities in modelling and simulation, instrumentation development and ground testing. The engineering approach and associated challenges and achievements in each of these disciplines are discussed albeit briefly. This ranges from the use of computational aerodynamics and structural modelling to predict blade dynamics to the development of direct fibre optic shape sensing that allows measurements above 1kHz over numerous positions on the blade. Moreover, the development of the prototype onboard system that overcomes the challenge of transferring data between the rotating main rotor to the fixed fuselage frames is also discussed.

Journal of Educational Thought / Revue de la Pensée Educative, Vol 19 No 2 (1985)

In this paper, we present how we created a Domain Specific Language (DSL) dedicated to IP Multimedia Subsystem (IMS) at Ericsson. First, we introduce IMS and how developers are burdened by its complexity when integrating it in their application. Then we describe the principles we followed to create our new IMS DSL from its core in the Scala language to its syntax. We then present how we integrated it in two existing projects and show how it can save time for developers and how readable the syntax of the IMS DSL is., 19 pages, 2 figures, 1 table, oral presentation at SDL 2013: Model-Driven Dependability Engineering conference

Tree growth and crown form of 131 open-grown and 63 forest-grown lodgepole pine were investigated. Areas sampled included representative sites in the Interior, Lower Mainland and Vancouver Island in British Columbia. Both graphical and multiple regression analyses were used. The best, but still inadequate, estimator of either radial or basal area growth for the last five years was the growth for the period six to ten years ago. Standard errors of estimate ranged from 21.4 percent for basal-area growth of individual open-grown trees to 43.5 percent for basal-area growth of individual forest-grown trees. More than 90 percent of the total variation in the crown width of open-grown lodgepole pine was accounted for by d.b.h. alone. For forest-grown trees only 56.8 percent was accounted for by d.b.h. This percentage may be increased to 81.1 percent by the addition of height-crown width (H/CW), and to 68.4 percent by the addition of crown width/diameter (CW/D). Average value for CW/D was 0.99 for the forest-grown, and 2.13 for 90 open-grown trees ten years of age or older. Both H/CW and CW/D are significantly related to site index and age. However, when d.b.h. is taken into account, only six percent of the variation in CW/D is affected by site index. Almost 50 percent of the height to the lowest dead branch, and over 90 percent of the height to the lowest live branch could be accounted for by tree age, d.b.h. and height. One of four "competition factors", all related to distance to, and size of, competing trees, accounted for an additional 13.7 percent of the variation in height to dead branches. However, basal area, H/CW, and CW/D were of little importance after the effects of age, d.b.h. and height were accounted for. The maximum growth rate for open-grown trees was determined graphically for ages from 30 to 50 years by site index classes. Comparison with normally grown trees showed that at least twice the normal yield-table-estimate of growth rate may be expected from open-grown trees. Using regression equations developed from the data, a theoretical conversion to lumber was made for a butt log from an open-grown tree. For boards, graded under the Western Pine Association's rules, it was shown that large knots may degrade lumber grown at the maximum rate. Therefore, use of an open-to-normal density model, which allows crowns to compete before excessive knot formation occurs, would be a desirable objective for management of lodgepole pine.

This thesis describes an optimization model for the allocation of logs from alternative sources for a series of successive time periods. The model was formulated as a multi-stage decision process and is solved by dynamic programming. The analytic framework consists of two connected recurrence equations, each incorporating two decision-variables. These two relationships, together with the feasibility regions defined for a hypothetical problem, describe the optimization process. The hypothetical allocation problem, used as a vehicle for model development, requires mill demands for quantities of pulplogs and sawlogs to be satisfied for three time periods. Logs are delivered from five available sources, four log-producing areas and an open log market, and temporary log surpluses are allowed. Only a limited quantity of logs is available from each source in each period, two of the four forest areas supply only pulplogs and a third area is inaccessible in one period. The variable unit costs of delivered logs differ not only between each source and period but are also dependent upon the magnitude of an allocation. In addition to satisfying mill demands for specified quantities of logs, there is a further requirement with regard to sawlogs. Average lumber prices are assumed to be dependent upon the tree species processed and variable log conversion costs are assumed to decrease with increase in log diameter. Consequently, the comparison of alternative allocation policies involves not only the sum of the variable delivered log costs but also a measure of the value of delivered sawlogs. In the thesis "sawlog net worth" is evaluated and combined with log production and log transportation costs to give a composite cost term, "net delivered log cost." This is the measure used to evaluate each allocation and is incorporated in the first of the two recurrence equations. This equation is used to derive minimum cost allocation policies for all possible quantities that may be allocated from each period. In the second equation the minimum costs derived from the first allocation process are combined with a second term to evaluate alternative allocations between periods. This second cost component is incurred when surplus logs are "cold-decked" for subsequent mill conversion. To ensure a sufficient flow of logs, and to take advantage of seasonal differences in "net delivered log costs," log surpluses are permitted. When log surpluses are "cold-decked" additional log handling costs are incurred which must be considered when alternative allocations between periods are evaluated. This requirement is satisfied by introducing the additional cost component into the second equation. The different derivations given for the "net delivered log costs" for five sources of logs demonstrate an important feature of the formulation: there is no requirement that costs must be linearly related to the quantity allocated. This freedom is well illustrated by the introduction of additional "fixed" costs which are dependent upon the magnitudes of the quantities allocated. In a demonstration of the flexibility of the formulation a complex log production system was assumed for source two. For each allocation from this source two optimal quantities were derived. The first was the quantity of sawlogs selected from specified log classes, the second was the optimal portion of the quantity of peeler logs developed that should be traded. An exchange could be made either for sawlogs, or for pulplogs, or both. With the development of this log allocation model a fresh approach to log production planning is now possible. The analytic framework is capable of extensive adaptation and the model itself can be readily modified to suit a variety of conditions. Whether used as described, or as part of a larger analytical system, the computational advantages of dynamic programming are now available to the planner.