Discovering Evolutionary Stepping Stones through Behavior Domination

Behavior domination is proposed as a tool for understanding and harnessing the power of evolutionary systems to discover and exploit useful stepping stones. Novelty search has shown promise in overcoming deception by collecting diverse stepping stones, and several algorithms have been proposed that combine novelty with a more traditional fitness measure to refocus search and help novelty search scale to more complex domains. However, combinations of novelty and fitness do not necessarily preserve the stepping stone discovery that novelty search affords. In several existing methods, competition between solutions can lead to an unintended loss of diversity. Behavior domination defines a class of algorithms that avoid this problem, while inheriting theoretical guarantees from multiobjective optimization. Several existing algorithms are shown to be in this class, and a new algorithm is introduced based on fast non-dominated sorting. Experimental results show that this algorithm outperforms existing approaches in domains that contain useful stepping stones, and its advantage is sustained with scale. The conclusion is that behavior domination can help illuminate the complex dynamics of behavior-driven search, and can thus lead to the design of more scalable and robust algorithms.Comment: To Appear in Proceedings of the Genetic and Evolutionary Computation Conference (GECCO 2017

Importance of Baryon-Baryon Coupling in Hypernuclei

The $\Lambda N - \Sigma N$ coupling in $\Lambda$--hypernuclei and $\Lambda \Lambda - \Xi N$ coupling in $\Lambda \Lambda$--hypernuclei produce novel physics not observed in the conventional, nonstrange sector. Effects of $\Lambda \leftrightarrow \Sigma$ conversion in $^3_{\Lambda}$H are reviewed. The role of $\Lambda N - \Sigma N$ coupling suppression in the $A=4,5$ $\Lambda$--hypernuclei due to Pauli blocking is highlighted, and the implications for the structure of $^{10}_{\;\, \Lambda}$B are explored. Suppression of $\Lambda \Lambda - \Xi N$ conversion in $^{\;\;\, 6}_{\Lambda \Lambda}$He is hypothesized as the reason that the $$ matrix element is small. Measurement of $^{\;\;\, 4}_{\Lambda \Lambda}$H is proposed to investigate the full $\Lambda \Lambda - \Xi N$ interaction. The implication for $\Lambda \Lambda$ analog states is discussed.Comment: 17 pages LATEX, 1 figure uuencoded postscrip

Circuit Theory

Contains reports on four research projects

Location and efficiency of the Iowa feed-manufacturing industry

The American commercial mixed-feeds industry has experienced rapid growth, especially since World War II. Changes have occurred in the product produced, in the number, size, location, and technology of plants, and in the number, size, and organization of the purchasers of the industry’s products. The purpose of this study was to develop and use an analytical procedure to solve for the efficient number, size, and location of plants in the Iowa feed-manufacturing industry. Such information should assist the industry in adjusting to rapidly changing demand and technology. The problematical situation out of which the specific objectives emerge is to find the least-cost location and size pattern for feed-manufacturing plants in Iowa. The solution should take account of changing levels of demand, the changing levels of available technology, and the commercialization trends of modem farming. Are the existing feed-manufacturing plants economically efficient in size? Are their locations optimal? Should there be more or fewer of them

Mathematics

Contains reports on three research projects

Children\u27s Literature and Literacy Instruction: Literature-Based Elementary Teachers Belief and Practices

In recent years, there has been growing interest nation wide among elementary teachers for using children\u27s literature as the core of the reading program. A national survey (Cullinan, 1989) indicated that many states are involved in literature-based initiatives, and some states, led by California, have mandated the use of literature (Alexander, 1987). Therefore, many teachers are making the transition from highly structured commercial reading programs to literature programs that require extensive teacher decision-making regarding materials, grouping, instructional practices, and assessment. Concerns are now being raised in the profession about the nature and appropriateness of some literature-based programs\u27 implementation (Gardner, 1988; Purves, 1990). For example, philosophical tension is growing between teaching reading with literature (suggesting a primarily literacy focus) and teaching literature (implying a stronger literary perspective). In fact, Purves (1990) bluntly pinpoints this conflict by asking whether literature can be rescued from reading (p.79)

Iowa’s grain-elevator industry: Factors affecting its organization and structural adjustment

In December 1970, there were 1,178 grain elevators in Iowa. The total storage capacity of these elevators was in excess of 432 million bushels. In recent years, both the number and the storage capacity of elevators have been increasing. More than half the elevators had a storage capacity of 300,000 bushels or less. This group, however, accounted for only 21 percent of the total storage capacity. The current organization of the industry is typified by an elevator that receives com and soybeans from a supply area with a radius of 5 to 7 miles. A statistical cost function, derived from data from over 150 cooperative elevators, indicated that significant economies of scale exist in elevator operations. This cost function showed that an elevator with a capacity of 300,000 bushels would have an average cost of 11 cents per bushel of grain handled, compared with a cost of 7.9 cents for an elevator with a capacity of 2 million bushels. Since the statistical cost function was based on accounting data reflecting historical investment costs and interest rates, these estimates of elevator costs should be regarded as conservative

p120-Catenin Down-Regulation and Epidermal Growth Factor Receptor Overexpression Results in a Transformed Epithelium That Mimics Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is an aggressive malignancy with a poor prognosis due to its highly invasive and metastatic potential. The molecular pathogenesis underlying the invasive mechanism of ESCC is not well known because of the lack of existing models to study this disease. p120-Catenin (p120ctn) and the epidermal growth factor receptor (EGFR) have each been implicated in several cancers, including ESCC. p120ctn is down-regulated in 60% of ESCC tumors, whereas EGFR is the most commonly overexpressed oncogene in ESCC. For these reasons, we investigated the cooperation between p120ctn and EGFR and its effect on ESCC invasion. We show that p120ctn down-regulation is commonly associated with EGFR overexpression. By using a three-dimensional culture system, we demonstrate that the inverse relationship between p120ctn and EGFR has biological implications. Specifically, p120ctn down-regulation coupled with EGFR overexpression in human esophageal keratinocytes (EPC1-PE) was required to promote invasion. Morphological comparison of EPC1-PE cells grown in three-dimensional culture and human ESCC revealed identical features, including significantly increased cellularity, nuclear grade, and proliferation. Molecular characteristics were measured by keratin expression patterns, which were nearly identical between EPC1-PE cells in three-dimensional culture and ESCC samples. Altogether, our analyses have demonstrated that p120ctn down-regulation and EGFR overexpression are able to mimic human ESCC in a relevant three-dimensional culture model

Idealness of k-wise intersecting families

A clutter is k-wise intersecting if every k members have a common element, yet no element belongs to all members. We conjecture that, for some integer k ≥ 4, every k-wise intersecting clutter is non-ideal. As evidence for our conjecture, we prove it for k = 4 for the class of binary clutters. Two key ingredients for our proof are Jaeger’s 8-flow theorem for graphs, and Seymour’s characterization of the binary matroids with the sums of circuits property. As further evidence for our conjecture, we also note that it follows from an unpublished conjecture of Seymour from 1975. We also discuss connections to the chromatic number of a clutter, projective geometries over the two-element field, uniform cycle covers in graphs, and quarter-integral packings of value two in ideal clutters