A performance measure for manual control systems

A new performance measure is introduced for multivariable closed loop experiments with a human operator. The essential feature of the phase margin performance measure (PMPM) is that the performance of each control loop can be determined independently, with prescribed disturbance and error levels. A variable filter parameter is used as the PMPM within the loop and it assures a high workload at the same time. There is a straightforward relationship between the PMPM and the inner loop feedback augmentation that can be utilized in trade-off studies. An adjustment scheme that seeks the PMPM automatically is described as employed in a single loop control task. This task applies directly to the experimental study of displays for helicopters and VTOL aircraft

The Role of Solar Wind Ion Processing in Space Weathering of Olivine: Unraveling the Paradox of Laboratory Irradiation Results Compared to Observations of Natural Samples

Ion irradiation by the solar wind plays a major role in space weathering. Among its multiple effects are ion damage and implantation processes that alter the crystal structure as well as chemical composition of the outer few 100 nanometers of space exposed regolith grains. This forms a portion of the space weathered rims on lunar and asteroidal regolith grains that is uniquely ion-processed. One aspect of these ion-processed grain rims is the possible link between their widths, and degree of ion damage, and the length of exposure of their host grain on the topmost surface of lunar and asteroidal regoliths. Ultimately, quantifying this link relies on laboratory ion irradiation experiments to calibrate the ion fluence or dose at which different degrees and depths of ion damage occur. Here we discuss evidence, specifically from the mineral olivine, suggesting there may be limitations in extrapolating the results of laboratory ion irradiation experiments to natural ion irradiation by the solar wind

Where Do We Stand on Closely-Held Firm Valuation?

This paper contains a review of issues pertaining to the valuation of privately held businesses, noting significant inconsistencies in the rationale and approaches taken in the valuation process. In addition to suggesting that appraisers stay with the tried and true rather than testing the obsolete, it may be desirable for an experiment to be conducted with a friends of the Tax Court idea, in which a few select extremely well qualified appraisers offer assistance in the Tax Court\u27s deliberations on valuation issues

Fluid Measure and Disbursement: Valuation of a Closely-Held Firm

There are about 24 million businesses in the United States, with something less than one-tenth of one percent actively traded. This case is hypothetical, but the valuation issues pertaining to many of those closely-held firms are real. The case illustrates an income statement adjustment, estimation of a required rate of return, application of discounts to an as if actively traded” price, and valuation treatment of excess assets not needed in the operation of the firm. The desire for market data is clear, but for closely-held firms market data must be proxied by the best available information and applied to sometimes less than complete information pertaining to valuation issues for closely-held business. Some of these techniques are applied in the solution of the case

A Process Writing Curriculum for Kindergarten Through Third Grade

The curriculum that has been developed for this project is designed to promote the implementation of process writing in kindergarten through third grade classrooms. Writing activities are planned within the content areas and present writing as a natural way to communicate throughout daily activities. The review of research reflects over fifteen years of work that has predominantly been carried out in classroom settings with elementary school students and teachers. Patterns of writing development have been identified that indicate a positive correlation between the students skills attainment and purposeful reading and writing experiences. The plan incorporates individualized instructional strategies that have evolved as a result of the findings of the researchers and teachers who have studied the process writing approach. Procedures for conferencing and teacher modeling techniques are illustrated in this project. The curriculum establishes the atmosphere of the classroom and outlines the stages of the writing process. Journal writing is planned as a daily activity with additional ongoing activities which encourage purposeful writing. The plan for the content areas is consistent with the whole language perspective. A culminating activity is included to provide an opportunity for students to apply the skills they have learned throughout the year. The evaluation of this project was accomplished through interviews with teachers and the presentation of an inservice program. Samples of writing that the students were currently producing were used to identify developmental stages and to model teaching techniques that were suggested in the plan. This curriculum presents writing as an integral part of daily classroom activities. The goal is for children to learn to write by writing and to develop a sense of authorship

A Mathematical Origami Puzzle

The recent axiomization of Origami has led to numerous breakthroughs in both mathematics and in understanding of the ancient art of paper folding. We propose a puzzle whose solution demonstrates the power of mathematical origami. This puzzle is accessible to the geometry student and could be used as supplemental geometry instruction as an extension of traditional compass and straight edge constructions. Detailed images and photos are provided to guide the audience through the puzzle’s solution

Valuation of Closely-Held Firms: Another Look

For the most part, closely-held firms must be valued using proxies for market data which are not available. Valuation approaches described in the literature are used by practitioners with exceptions demanded by circumstances. Results of the survey confirm statements of others that substantial discounts for non-marketability and minority interest are usually appropriate

Sets of three pairwise orthogonal Steiner triple systems

AbstractTwo Steiner triple systems (STS) are orthogonal if their sets of triples are disjoint, and two disjoint pairs of points defining intersecting triples in one system fail to do so in the other. In 1994, it was shown (Canad. J. Math. 46(2) (1994) 239–252) that there exist a pair of orthogonal Steiner triple systems of order v for all v≡1,3 (mod6), with v⩾7, v≠9. In this paper we show that there exist three pairwise orthogonal Steiner triple systems of order v for all v≡1(mod6), with v⩾19 and for all v≡3(mod6), with v⩾27 with only 24 possible exceptions