Formation control and collision avoidance for a class of multi-agent systems

In this paper, a control scheme is proposed for a group of elliptical agents to achieve a predefined formation. The agents are assumed to have the same dynamics, and communication among the agents are limited. The desired formation is realized based on the reference formation and the mapping decision. In the control design, searching algorithms for both cases of minimum distance and tangents are established for each agent and its neighbors. In order to avoid collision, an optimal path planning algorithm based on collision angles, and a self-center-based rotation algorithm are also proposed. Moreover, randomized method is used to provide the optimal mapping decision for the underlying system. Two examples and analyses are presented to demonstrate the effectiveness and potential of the new control scheme.     

Impact of combining data from multiple instruments on performance of patient-based real-time quality control

IntroductionIt is unclear what is the best strategy for applying patient-based real-time quality control (PBRTQC) algorithm in the presence of multiple instruments. This simulation study compared the error detection capability of applying PBRTQC algorithms for instruments individually and in combination using serum sodium as an example.Materials and methodsFour sets of random serum sodium measurements were generated with differing means and standard deviations to represent four simulated instruments. Moving median with winsorization was selected as the PBRTQC algorithm. The PBRTQC parameters (block size and control limits) were optimized and applied to the four simulated laboratory data sets individually and in combination.ResultsWhen the PBRTQC algorithm were individually optimized and applied to the data of the individual simulated instruments, it was able to detect bias several folds faster than when they were combined. Similarly, the individually applied algorithms had perfect error detection rates across different magnitudes of bias, whereas the error detection rates of the algorithm applied on the combined data missed smaller biases. The performance of the individually applied PBRTQC algorithm performed more consistently among the simulated instruments compared to when the data were combined.DiscussionWhile combining data from different instruments can increase the data stream and hence, increase the speed of error detection, it may widen the control limits and compromising the probability of error detection. The presence of multiple instruments in the data stream may dilute the effect of the error when it only affects a selected instrument.     

Initiating Cultural Shifts in Perceptions of Cataloging Units through Interaction Assessment

Points of contact formulate the culture of any organization and shape the perceptions of decision makers and colleagues alike. This research project investigated the interactions between Cataloging and Metadata Services staff and other library employees by analyzing interactions. This article summarizes the results of data gathered from interaction assessments and compares them with surveys about the current perceptions of the cataloging unit at the Utah State University Libraries. It discusses the ways these results have influenced existing unit workflows to enhance awareness of cataloging and metadata contributions to the library and posits possible ways to continue such initiatives moving forward.     

提心吊胆的华尔街

The war in Iraq, terrorism, rising oil prices-and now the threat of higher interest rates-are all preying on the market. There comes a point in virtually every bull market when     

The Relationship of Spelling Recognition, RAN, and Phonological Awareness to Reading Skills in Older Poor Readers and Younger Reading-Matched Controls

The role of spelling recognition was examined in word reading skills and reading comprehension for dyslexic and nondyslexic children. Dyslexic and nondyslexic children were matched on their raw word reading proficiency. Relationships between spelling recognition and the following were examined for both groups of children: verbal ability, working memory, phonological measures, rapid naming, word reading, and reading comprehension. Children’s performance in spelling recognition was significantly associated with their skills in word reading and reading comprehension regardless of their reading disability status. Furthermore, spelling recognition contributed significant variance to reading comprehension for both dyslexic and nondyslexic children after the effects of phonological awareness, rapid naming, and word reading proficiency had been accounted for. The results support the role of spelling recognition in reading development for both groups of children and they are discussed using a componential reading fluency framework.     

Individual differences in negative group work experiences in collaborative student learning

This paper reports the development of the Negative Group Work Experiences questionnaire (NGWE), an assessment tool for measuring negative experiences of group work. Study 1 involved two samples of undergraduate psychology students (second‐year sample n = 425; first‐year sample n = 443), who completed research modules incorporating substantial elements of assessed group work. Participants completed a 39‐item inventory designed to measure their negative experiences of group work as part of their general module evaluation. Exploratory and confirmatory factor analysis of the second‐year sample indicated four interpretable and reliable factors: lack of group commitment, group fractionation, task disorganisation, and storming. Confirmatory factor analysis of the first‐year data set confirmed and cross‐validated the factor structure of the second‐year sample. Study 2 (n > 254) confirmed the criterion validity of the NGWE. The NGWE is proposed as a useful tool for evaluating group processes, especially in large group teaching which involves collaborative group work.     

The coming of the new distance educators in the United States: the telecommunications generation takes off

The progress of video telconferencing in American education offers striking evidence of some of the wider effects that telecommunications promises to have on distance education. The term ‘distance education’ itself is taking on broad new meanings that separate it from traditional correspondence study. The growing acceptance of video telecommunications foreshadows the coming of a new generation of distance educators who see themselves as having less in common with correspondence study professionals than with each other.

Video applications to education are galvanizing educational structures in the United States, bringing profound change to every level. The impetus for this proliferating activity and the transformation that it is bringing lies neither with traditional distance educators nor, for the most pan, with higher education as a whole. The forces driving these developments are highly fluid but can be traced to an array of societal demands and an emerging perception of learners' needs that is ushering the users of technology into roles formerly held by distance educators. Above all, these forces give every indication of insuring that the new image of distance education will not only be pervasive but will be reflected on a video screen.     

从孟、荀看战国儒家政治文化之演进

孟子与荀子的政治观从表面上看大多是对立的，但在实际上并不矛盾，他们往往说的不是一个层面上的问题。就其政治大思路而言，二者是一致的，都倡导人治，都是道德主义的，有其“同归而殊途”的内在逻辑。