Closed-loop control of hydraulic telescopic handler

Automatization is supposed to improve working conditions and safety in the construction industry, as it already did in manufacturing industries. This paper presents the development of a robotic control system for a commercially available hydraulic telescopic handler. The target application for the telescopic handler is semi-automated assembly of facade panels. The base handler was upgraded with two additional hydraulic axes, position sensors and closed-loop control system, while the original handler safety assurance mechanisms were preserved. The control approach is based on a PI controller with velocity feedforward and valve overlap compensation. The direct and inverse kinematic models of handler mechanism were developed to enable control of end-effector motion along a straight line in the Cartesian coordinate system. The motion performances were evaluated following the ISO 9283 standard with payload of 2000 kg. Results show the repeatability of positioning bellow 7.0 mm and the straight line tracking error smaller than 63 mm.     

Assessing the Impacts of Nutrient Load Uncertainties on Predicted Truckee River Water Quality

This study examined the effects of uncertain model boundary conditions on dissolved oxygen (DO) predictions for the lower Truckee River, Nevada using an augmented version of the EPA’s Water Quality Analysis Simulation Program Version 5 (WASP5) that included periphyton, or attached algae, in eutrophication kinetics. Uncertainty analyses were performed on selected organic nitrogen (ON) and carbonaceous biochemical oxygen demand boundary conditions using Monte Carlo techniques. The stochastic model was run using boundary concentrations assigned from observed probability distributions. Ranges of simulated values were used to construct confidence intervals, the magnitudes of which indicated the uncertainty associated with model predictions. Uncertainty in agricultural ditch return concentrations had minimal effects on in-stream model predictions, as predicted values of daily minimum and maximum DOs, daily average ON, and periphyton biomass all failed to show significant variability as a result of ditch concentration uncertainty. This result indicates that while ditch return nutrient loads are not trivial, their exact concentrations are not needed to make relatively accurate predictions of in-stream DO. However, uncertainty in the upstream ON boundary did result in significant uncertainty during summer months with regard to in-stream model predictions of ON, periphyton biomass, and DO. The model is clearly more sensitive to changes in this boundary than to changes in agricultural ditch concentrations.     

Seasonal fouling on seawater desalination RO membrane

A pilot study has been performed to investigate the seasonal characteristic of seawater reverse osmosis (RO) membrane fouling. Two batches of experiment during summer and winter were both performed 18 days to provide a clear picture on microbial population variability. The feed water of the pilot from seawater desalination plant has significant difference in temperature and silica content between the two seasons.In our experiments, scaling and biofouling are more serious in summer. And the permeate flux decline is closely related to the rise in microbial population, and it was dominated by cell multiplication rather than adhesion. In addition, the summer cell multiplication is much more abundant. Moreover, the extracellular polymeric substance (EPS) feature intensity detected by Fourier-transform infrared spectroscopy was also stronger in summer. The abundant EPS was one of the major reasons to cause the inorganic matter adsorption. Si, Al, Fe, Ca and Mg were found as the major inorganic foulants deposited on the Ro membranes. Silica and calcium in summer appeared obvious higher amounts than that in winter, which indicated that they should be affected by microbial action directly or indirectly more than other elements.In summary, there exists a seasonal effect on membrane scaling and fouling, and scaling is associated with biofouling in some degree. Further researches could be focus on actual association between microbial action and inorganic fouling.     

Decisions,decisions: analysis of age,cohort, and time of testing on framing of risky decision options

Decision making in uncertain environments is a daily challenge faced by adults of all ages. Framing decision options as either gains or losses is a common method of altering decision-making behavior. In the experiment reported here, benchmark decision-making data collected in the 1970s by Tversky and Kahneman (1981, 1988) were compared with data collected from current samples of young and older adults to determine whether behavior was consistent across time. Although differences did emerge between the benchmark and the present samples, the effect of framing on decision behavior was relatively stable. The present findings suggest that adults of all ages are susceptible to framing effects. Results also indicated that apparent age differences might be better explained by an analysis of cohort and time-of-testing effects. Actual or potential applications of this research include an understanding of how framing might influence the decision-making behavior of people of all ages in a number of applied contexts, such as product warning interactions and medical decision scenarios.     

Efficient query expansion with auxiliary data structures

Query expansion is a well-known method for improving average effectiveness in information retrieval. The most effective query expansion methods rely on retrieving documents which are used as a source of expansion terms. Retrieving those documents is costly. We examine the bottlenecks of a conventional approach and investigate alternative methods aimed at reducing query evaluation time. We propose a new method that draws candidate terms from brief document summaries that are held in memory for each document. While approximately maintaining the effectiveness of the conventional approach, this method significantly reduces the time required for query expansion by a factor of 5–10.     

Searchable words on the Web

In designing data structures for text databases, it is valuable to know how many different words are likely to be encountered in a particular collection. For example, vocabulary accumulation is central to index construction for text database systems; it is useful to be able to estimate the space requirements and performance characteristics of the main-memory data structures used for this task. However, it is not clear how many distinct words will be found in a text collection or whether new words will continue to appear after inspecting large volumes of data. We propose practical definitions of a word and investigate new word occurrences under these models in a large text collection. We inspected around two billion word occurrences in 45 GB of World Wide Web documents and found just over 9.74 million different words in 5.5 million documents; overall, 1 word in 200 was new. We observe that new words continue to occur, even in very large datasets, and that choosing stricter definitions of what constitutes a word has only limited impact on the number of new words found.     

An algorithm for computing the restriction scaffold assignment problem in computational biology

Let S and T be two finite sets of points on the real line with |S|+|T|=n and |S|>|T|. The restriction scaffold assignment problem in computational biology assigns each point of S to a point of T such that the sum of all the assignment costs is minimized, with the constraint that every element of T must be assigned at least one element of S. The cost of assigning an element si of S to an element tj of T is |si−tj|, i.e., the distance between si and tj. In 2003 Ben-Dor, Karp, Schwikowski and Shamir [J. Comput. Biol. 10 (2) (2003) 385] published an O(nlogn) time algorithm for this problem. Here we provide a counterexample to their algorithm and present a new algorithm that runs in O(n²) time, improving the best previous complexity of O(n³).     

平台2015:Intel处理器及平台在下一个十年的演化

毫无疑问,近年来计算技术取得了长足的进步。但是,在未来的十年,主流计算技术中新的工作量、使用模式的出现及变化对未来的计算平台提出的要求,与过去十年所取得的进展也差不多,这些巨大的要求包括:更高的性能、更低的功率密度、更好的功能可扩展性。倘若出现这些使用计算机的震撼性的变化,我们怎样定义和构架未来的计算平台,就将不得不做出引人注目的改变。要整体地理解和满足的,不仅仅有计算的需要,而且还有接口以及系统基础设施的需要。Intel对这三个基础平台要素的演化的长期设想,以及驱动演化的架构的创新和核心能力,即是我们称之为平台2015(Platform2015)的内容。除了考察相关的趋势、使用、平台处理含意之外,本文将集中在平台2015的计算单元,描述Intel微处理器架构在未来十年的演化。     

Long-Term Dynamic Modeling Approach to Quantifying Attached Algal Growth and Associated Impacts on Dissolved Oxygen in the Lower Truckee River, Nevada

Nutrient loads enter the lower Truckee River of western Nevada, affecting the growth of attached algae (periphyton) which causes depressed nighttime dissolved oxygen (DO) levels. The lower Truckee River is home to the endangered cui-ui and threatened Lahontan cut-throat trout, with DO standards being established to in part protect these species. Hydrodynamics, nutrient concentrations, periphyton biomass, and DO data spanning August 2000–December 2001 were used to calibrate and verify a modified version of the Water Quality Analysis Simulation Program Version 5 (WASP5). Under typical loading conditions the periphyton community is nitrogen limited, however nitrogen loading from an upstream wastewater treatment facility increased greatly during the analysis period due to approved site construction activities (discharge permit excursion) causing the periphyton community to temporarily become phosphorus limited. The developed modeling approach, with limited calibration, was able to accurately track dynamic system responses. Removing the impact of the noted discharge permit excursion resulted in a minimum computed DO value of 4.13?mg/L, occurring at the downstream end of the modeling domain on August 8, 2001. Additionally removing the impact of all nutrient loads from area agriculture resulted in a predicted minimum DO value of 4.54?mg/L, while also shifting its location significantly upstream and its timing to April 26, 2001. Meeting all prescribed DO standards required establishing a minimum in-stream flow value of 1.81?m3/s (64.0?ft3/s) downstream of Derby Dam.