1,969 research outputs found
Searching for a Double 10-By-10
Avid readers of Word Ways may remember that I attempted a computer search for 10-by-10 word squares a number of years ago. I had a vocabulary of 55,000 ten-letter word and phrases stored in the computer, about half dictionary words and the rest names and phrases I had devised from brainstorming and free association. For example, I\u27d pick a word like carpet and think of all the things that go with it like -bags, bugs, tack, roll, shop, - less, - like, etc. My best effort, a square containing eight words from Webster\u27s Second, appearing in the February 1977 Word Ways
Lying in Wait
Many years ago, a friend challenged me to name an adjective, as opposed to an adverb, ending in LY. I do not recall if I succeeded, but the problem remained in my subconscious, and has surfaced at irregular intervals ever since. Occasionally I would sit down and mentally compose a list of ten or fifteen such words, each time trying to surpass my last effort
Inversion Squares
It is now approaching two years since I began a computer search for a 10x10 word square. Since my last report in the November 1989 Word Ways, there has been a discouraging turn in events. I furnished statistics about the distribution of letter-frequencies in my wordstock to a researcher at the IBM Yorktown Research Center. He calculated, given these letter-frequencies, that a vocabulary of 289,000 words would be required to produce a symmetric 10x10 word square. I had already projected that when I finished transcribing the Levine list, there still would be fewer than 130,000 words -- less than half the required number
The Contest Center
About a year ago, I started a small company to run word puzzle contests. I called it The Contest Center, a rather pretentious name, but one I hoped would fit as the company grew to what conceivably could become my regular occupation when I retired
10-By-10 Squares: Progress Report
In the August 1988 Word Ways, I wrote about my plans to launch a computer attack on the 10-by-10 double word square. I asked for help from Word Ways readers who might help gather 10-letter words from dictionaries and other sources. I received only one reply, from George H. Ropes, who had just written an article on his own search for a 10-by-10 word square. He had the Air force word list from Webster\u27s Second on diskettes, and graciously supplied those diskettes to me
10-By-10 Squares: Another Update
It has now been one year since I began my computer search for 10x10 double word square. My efforts have been directed against three main obstacles: the need to obtain a massive number of words, the limited speed of a personal computer, and its limited storage
USING NONDESTRUCTIVE TESTING TO IDENTIFY PREMIUM GRADES IN SOUTHERN PINE AND DOUGLAS-FIR UTILITY CROSSARMS
Unlike lumber, wood utility crossarms are not currently available in premium grades that indicate a higher level of performance in service. Previous research has shown that nondestructive testing (NDT) techniques are able to predict performance properties of solid wood products with considerable accuracy. The aim of this study was to determine the suitability of NDT methods for predicting the stiffness and strength properties of wood utility crossarms and possibly aiding in the identification of a premium grade that exhibits higher average performance values. Samples of Douglas-fir and southern pine were subjected to multiple NDT technologies to estimate modulus of elasticity (MOE). Each specimen was also measured for MOE and modulus of rupture (MOR) with a static bending test. Bivariate correlations and corresponding R2 values showed that Fibre-gen’s Director HM200 and Metriguard’s E-computer were the most accurate NDT devices among those tested for predicting both MOR and MOE. Means tests also suggested that the devices could possibly be used to identify a premium grade that shows significantly higher average performance values
Lightweight, Low-CTE Tubes Made From Biaxially Oriented LCPs
Tubes made from biaxially oriented liquid-crystal polymers (LCPs) have been developed for use as penetrations on cryogenic tanks. ( Penetrations in this context denotes feed lines, vent lines, and sensor tubes, all of which contribute to the undesired conduction of heat into the tanks.) In comparison with corresponding prior cryogenic-tank penetrations made from stainless steels and nickel alloys, the LCP penetrations offer advantages of less weight and less thermal conduction. An additional major advantage of LCP components is that one can tailor their coefficients of thermal expansion (CTEs). The estimated cost of continuous production of LCP tubes of typical sizes is about 4.17/m) [based on 1998 prices]. LCP tubes that are compatible with liquid oxygen and that feature tailored biaxial molecular orientation and quasi-isotropic properties (including quasi-isotropic CTE) have been fabricated by a combination of proprietary and patented techniques that involve the use of counterrotating dies (CRDs). Tailoring of the angle of molecular orientation is what makes it possible to tailor the CTE over a wide range to match the CTEs of adjacent penetrations of other tank components; this, in turn, makes it possible to minimize differential-thermal expansion stresses that arise during thermal cycling. The fabrication of biaxially oriented LCP tubes by use of CRDs is not new in itself. The novelty of the present development lies in tailoring the orientations and thus the CTEs and other mechanical properties of the LCPs for the intended cryogenic applications and in modifications of the CRDs for this purpose. The LCP tubes and the 304-stainless-steel tubes that the LCP tubes were intended to supplant were tested with respect to burst strength, permeability, thermal conductivity, and CTE
Truth and Deception at the Rhetorical Structure Level
This paper furthers the development of methods to dis- tinguish truth from deception in textual data. We use rhetorical structure theory (RST) as the analytic framework to identify systematic differences between deceptive and truthful stories in terms of their coher- ence and structure. A sample of 36 elicited personal stories, self-ranked as truthful or deceptive, is manu- ally analyzed by assigning RST discourse relations among each story’s constituent parts. A vector space model (VSM) assesses each story’s position in multi- dimensional RST space with respect to its distance from truthful and deceptive centers as measures of the story’s level of deception and truthfulness. Ten human judges evaluate independently whether each story is deceptive and assign their confidence levels (360 evaluations total), producing measures of the expected human ability to recognize deception. As a robustness check, a test sample of 18 truthful stories (with 180 additional evaluations) is used to determine the reli- ability of our RST-VSM method in determining decep- tion. The contribution is in demonstration of the discourse structure analysis as a significant method for automated deception detection and an effective complement to lexicosemantic analysis. The potential is in developing novel discourse-based tools to alert information users to potential deception in computer- mediated texts
Natural selection. II. Developmental variability and evolutionary rate
In classical evolutionary theory, genetic variation provides the source of
heritable phenotypic variation on which natural selection acts. Against this
classical view, several theories have emphasized that developmental variability
and learning enhance nonheritable phenotypic variation, which in turn can
accelerate evolutionary response. In this paper, I show how developmental
variability alters evolutionary dynamics by smoothing the landscape that
relates genotype to fitness. In a fitness landscape with multiple peaks and
valleys, developmental variability can smooth the landscape to provide a
directly increasing path of fitness to the highest peak. Developmental
variability also allows initial survival of a genotype in response to novel or
extreme environmental challenge, providing an opportunity for subsequent
adaptation. This initial survival advantage arises from the way in which
developmental variability smooths and broadens the fitness landscape.
Ultimately, the synergism between developmental processes and genetic variation
sets evolutionary rate
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