Footprint generation using fuzzy-neighborhood clustering

Geometric footprints, which delineate the region occupied by a spatial point pattern, serve a variety of functions in GIScience. This research explores the use of two density-based clustering algorithms for footprint generation. First, the Density-Based Spatial Clustering with Noise (DBSCAN) algorithm is used to classify points as core points, non-core points, or statistical noise; then a footprint is created from the core and non-core points in each cluster using convex hulls. Second, a Fuzzy-Neighborhood (FN)-DBSCAN algorithm, which incorporates fuzzy set theory, is used to assign points to clusters based on membership values. Then, two methods are presented for delineating footprints with FN-DBSCAN: (1) hull-based techniques and (2) contouring methods based on interpolated membership values. The latter approach offers increased flexibility for footprint generation, as it provides a continuous surface of membership values from which precise contours can be delineated. Then, a heuristic parameter selection method is described for FN-DBSCAN, and the approach is demonstrated in the context of wildlife home range estimation, where the goal is to a generate footprint of an animal’s movements from tracking data. Additionally, FN-DBSCAN is applied to produce crime footprints for a county in Florida. The results are used to guide a discussion of the relative merits of the new techniques. In summary, the fuzzy clustering approach offers a novel method of footprint generation that can be applied to characterize a variety of point patterns in GIScience.     

Zeolite synthesis from paper sludge ash at low temperature (90 degrees C) with addition of diatomite

Paper sludge ash was partially converted into zeolites by reaction with 3M NaOH solution at 90 degrees C for 24 h. The paper sludge ash had a low abundance of Si and significant Ca content, due to the presence of calcite that was used as a paper filler. Diatomite was added to the NaOH solution to increase its Si content in order to synthesize zeolites with high cation exchange capacity. Diatomite residue was filtered from solution before addition of ash. The original ash without addition of diatomite yielded hydroxysodalite with a cation exchange capacity ca. 50 cmol/kg. Addition of Si to the solution yielded Na-P1 (zeolite-P) with a higher cation exchange capacity (ca. 130 cmol/kg). The observed concentrations of Si and Al in the solution during the reaction explain the crystallization of these two phases. The reaction products were tested for their capacity for PO(4)(3-) removal from solution as a function of Ca(2+) content, suggesting the formation of an insoluble Ca-phosphate salt. The product with Na-P1 exhibits the ability to remove NH(4)(+) as well as PO(4)(3-) from solution in concentrations sufficient for application in water purification. Both NH(4)(+) and PO(4)(3-) removal showed little variation with pH between 5 and 9. Alternative processing methods of zeolite synthesis, including the addition of ash to an unfiltered Si-NaOH solution and addition of a dry ash/diatomite mixture to NaOH solution, were tested. The third process yielded materials with lower cation exchange capacity due to formation of hydroxysodalite. The second process results in a product with relatively high cation exchange capacity, and reduces the number of processing steps necessary for zeolite synthesis.     

System for foreign exchange trading using genetic algorithms and reinforcement learning

Foreign exchange trading has emerged recently as a significant activity in many countries. As with most forms of trading, the activity is influenced by many random parameters so that the creation of a system that effectively emulates the trading process will be very helpful. A major issue for traders in the deregulated Foreign Exchange Market is when to sell and when to buy a particular currency in order to maximize profit. This paper presents novel trading strategies based on the machine learning methods of genetic algorithms and reinforcement learning.     

电阻式触摸屏实现人机接口

引言 触摸屏接口对包括个人数字助理(PDA)等在内的许多信息设备都很有用,而且还可在测量与控制应用中用作通用指示设备.如何将通过触摸屏获得的信息传递给微处理器呢?这项工作可能具有相当的挑战性.本文将介绍电阻式触摸屏的工作原理,并指出如何最有效地将模拟输入转换为可用的数字数据.我们将讨论建立时间、噪声过滤以及速度权衡等问题.     

Work-sample tests of trainability: A meta-analysis.

The difference between normal work-sample tests and trainability tests is described, in that the former are for trained people and the latter are tests that incorporate a learning period and are specifically for untrained people. Several meta-analyses were conducted using different predictor criterion pairs. Total Ns?=?2,542 and 2,772. The meta-analyses were based on independent samples on which information was available on sample size, validity coefficient, type of predictor and, in most cases, type of criterion and length of follow-up period. The results of the meta-analyses suggest that trainability work-sample tests predict short-term training success more accurately than longer term training success, but there may be greater situational variability when short-term follow-up periods are involved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The panE gene, encoding ketopantoate reductase, maps at 10 minutes and is allelic to apbA in Salmonella typhimurium

In Salmonella typhimurium, precursors to the pyrimidine moiety of thiamine are synthesized de novo by the purine biosynthetic pathway or the alternative pyrimidine biosynthetic (APB) pathway. The apbA gene was the first locus defined as required for function of the APB pathway (D. M. Downs and L. Petersen, J. Bacteriol. 176:4858-4864, 1994). Recent work showed the ApbA protein catalyzes the NADPH-specific reduction of ketopantoic acid to pantoic acid. This activity had previously been associated with the pantothenate biosynthetic gene panE. Although previous reports placed panE at 87 min on the Escherichia coli chromosome, we show herein that apbA and panE are allelic and map to 10 min on both the S. typhimurium and E. coli chromosomes. Results presented here suggest that the role of ApbA in thiamine synthesis is indirect since in vivo labeling studies showed that pantoic acid, the product of the ApbA-catalyzed reaction, is not a direct precursor to thiamine via the APB pathway.     

Self-esteem as an interpersonal monitor: The sociometer hypothesis.

Five studies tested hypotheses derived from the sociometer model of self-esteem according to which the self-esteem system monitors others' reactions and alerts the individual to the possibility of social exclusion. Study 1 showed that the effects of events on participants' state of self-esteem paralleled their assumptions about whether such events would lead others to accept or reject them. In Study 2, participants' ratings of how included they felt in a real social situation correlated highly with their self-esteem feelings. In Studies 3 and 4, social exclusion caused decreases in self-esteem when respondents were excluded from a group for personal reasons, but not when exclusion was random, but this effect was not mediated by self-presentation. Study 5 showed that trait self-esteem correlated highly with the degree to which respondents generally felt included versus excluded by other people. Overall, results provided converging evidence for the sociometer model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine modulates effort-based decision making in rats.

Previous research has implicated dopamine as a modulating factor in choice behavior based on effort. The purpose of the present study was to determine the individual contribution of different dopamine receptors to effort-based decision making in rats. Rats were trained in a T-maze to choose a large-reward arm that contained 8 pellets of food over a small-reward arm that contained 2 pellets of food. The rats then were trained to climb progressively higher barriers to obtain the food from the large-reward arm. Using a discounting procedure on each test day, it was found that rats were more likely to choose the small-reward arm after treatment with the D1 antagonist, SCH-23390, or the D2 antagonist, haloperidol. The dopamine agonist, D-amphetamine, biased the rats toward choosing the large-reward arm and blunted the effects of SCH-23390 or haloperidol. Treatment with the D3 receptor antagonist, U99194, or the D3 receptor agonist, 7-OH-DPAT, did not alter choice behavior. These data indicate that D1 and D2 receptors are required for decisions based on effort. (PsycINFO Database Record (c) 2010 APA, all rights reserved)