For decades, vocabulary size tests have been built upon the idea that if a test-taker knows enough words at a given level of frequency based on a list from corpus, they will also know other words of that approximate frequency as well as all words that are more frequent. However, many vocabulary size tests are based on corpora that are as out-of-date as 70 years old and that may be ill-suited for these tests. Based on these potentially problematic areas, the following research questions were asked. First, to what degree would a vocabulary size test based on a large, contemporary corpus be reliable and valid? Second, would it be more reliable and valid than previously designed vocabulary size tests? Third, do words across, 1,000-word frequency bands vary in their item difficulty? In order to answer these research questions, 403 ESL learners took the Vocabulary of American English Size Test (VAST). This test was based on a words list generated from the Corpus of Contemporary American English (COCA). This thesis shows that COCA word list might be better suited for measuring vocabulary size than lists used in previous vocabulary size assessments. As a 450-million-word corpus, it far surpasses any corpus used in previously designed vocabulary size tests in terms of size, balance, and representativeness. The vocabulary size test built from the COCA list was both highly valid and highly reliable according to a Rasch-based analysis. Rasch person reliability and separation was calculated to be 0.96 and 4.62, respectively. However, the most significant finding of this thesis is that frequency ranking in a word list is actually not as good of a predictor of item difficulty in a vocabulary size assessment as perhaps researchers had previously assumed. A Pearson correlation between frequency ranking in the COCA list and item difficulty for 501 items taken from the first 5,000 most frequent words was 0.474 (r^2 = 0.225) meaning that frequency rank only accounted for 22.5% of the variability of item difficulty. The correlation decreased greatly when item difficulty was correlated against bands of 1,000 words to a weak r = 0.306, (r^2 = 0.094) meaning that 1,000-word bands of frequency only accounts for 9.4% of the variance. Because frequency is a not a highly accurate predictor of item difficulty, it is important to reconsider how vocabulary size tests are designed.

This study aims to explore the socialization issues of new-coming professional engineers. Based on theory socialization, social learning theory and social information processing approach, this study attempts to introduce work group socialization (group level) and self socialization (individual level), i.e., information seeking behavior, to the research model simultaneously. It is to improve the inconsistency between theories and empirical studies, and further to provide integral perspective on newcomer¡¦s socialization issues. Therefore, this study applies cross-level research design to explore and analyze relationships among socialization tactics at group and individual level, role breath self-efficacy and role performance. Collecting data from 91 groups, which include 91 immediate supervisors and 384 new-coming professional engineers, the research draws conclusion in two dimensions: (1) information seeking behavior, role breath self-efficacy, and role performance relationships at individual level; (2) socialization tactics, role breath self-efficacy and role performance relationships at cross-level. At the individual level, the results show that (1) when individuals apply overt, third party, and observation as the information seeking behaviors, there is a positive effect on role performance; when apply indirect and test as the information seeking behaviors, there is a negative effect on role performance. (2) When individuals apply ¡§overt¡¨, ¡§third party¡¨, and ¡§observation¡¨ as the information seeking behaviors, there is a positive effect on role breath self-efficacy; when apply ¡§indirect¡¨ and ¡§test¡¨ as the information seeking behaviors, there is a negative effect on role breath self-efficacy. (3) When individuals have high level of role breath self-efficacy, they are more willing to undertake tasks beyond work requirement, and thus have significant increase in role performance. (4) Role breath self-efficacy has full mediating effect on the relationship between overt, indirect, third party, test and role performance, and it has partial mediating effect on the relationship between observation and role performance. At the cross-level, it is found that (1) when the groups adopt ¡§investiture¡¨ and ¡§sequential¡¨ socialization tactics, the individual¡¦s role performance is positively increased; when the groups adopt ¡§collective¡¨, ¡§formal¡¨, ¡§serial¡¨ and ¡§fixed¡¨ socialization tactics, there is no significant influence on individual¡¦s role performance. (2) The level of groups¡¦ ¡§collective tactic¡¨ has negative moderating effect on the relationship between individual¡¦s ¡§third party¡¨ information seeking behavior and role breadth self-efficacy; ¡§sequential tactic¡¨ has positive moderating effects on the relationship between third-party information seeking behavior and role breadth self-efficacy; ¡§formal tactic¡¨ has negative moderating effect on the relationship between ¡§testing¡¨ information seeking behavior and role breadth self-efficacy; sequential tactic and fixed tactic have negative moderating effect on the relationship between observation information seeking behavior and role breadth self-efficacy; and serial tactic have positive moderating effect on the relationship between observation information seeking behavior and role breadth self-efficacy. (3) Each socialization tactic does not have direct contextual effect on role breath self-efficacy, while role breath self-efficacy also does not have mediating effect on the relationship between socialization tactics and role performance.

A connected dominating set D is a set of vertices of a graph G=(V,E) such that every vertex in V-D is adjacent to at least one vertex in D and the subgraph induced by the set D is connected. The connected domination number is the minimum of the cardinalities of the connected dominating sets of G. The problem of finding a minimum connected dominating set D is known to be NP-hard. Many polynomial time algorithms that achieve some approximation factors have been provided earlier in finding a minimum connected dominating set. In this work, we present a survey on known properties of graph domination as well as some approximation algorithms. We implemented some of these algorithms and tested them with random graphs and compared their performance in finding a minimum connected dominating set D.

abstract: This study exmaines the effect of in-vehicle infotainment display depth on driving performance. More features are being built into infotainment displays, allowing drivers to complete a greater number of secondary tasks while driving. However, the complexity of completing these tasks can take attention away from the primary task of driving, which may present safety risks. Tasks become more time consuming as the items drivers wish to select are buried deeper in a menu’s structure. Therefore, this study aims to examine how deeper display structures impact driving performance compared to more shallow structures. Procedure. Participants complete a lead car following task, where they follow a lead car and attempt to maintain a time headway (TH) of 2 seconds behind the lead car at all times, while avoiding any collisions. Participants experience five conditions where they are given tasks to complete with an in-vehicle infotainment system. There are five conditions, each involving one of five displays with different structures: one-layer vertical, one-layer horizontal, two-layer vertical, two-layer horizontal, and three-layer. Brake Reaction Time (BRT), Mean Time Headway (MTH), Time Headway Variability (THV), and Time to Task Completion (TTC) are measured for each of the five conditions. Results. There is a significant difference in MTH, THV, and TTC for the three-layer condition. There is a significant difference in BRT for the two-layer horizontal condition. There is a significant difference between one- and two-layer displays for all variables, BRT, MTH, THV, and TTC. There is also a significant difference between one- and three-layer displays for TTC. Conclusions. Deeper displays negatively impact driving performance and make tasks more time consuming to complete while driving. One-layer displays appear to be optimal, although they may not be practical for in-vehicle displays. / Dissertation/Thesis / Masters Thesis Human Systems Engineering 2018

The remarkable diversity of plant-feeding insects could be explained by the dynamics of their plant associations, where host plant shifts and specialization onto a small fraction of available plants may promote diversification. Neotropical Adelpha butterflies contain a large number of species, and previous work indicated the colonization of a novel host plant family (Rubiaceae) fueled its rapid diversification. However, accumulating host records indicate wide taxonomic host breadth at family level and below. Here, we categorize Adelpha diet breadth based on known host plant relationships across the Neotropics and from Costa Rica, Ecuador and Brazil. We also use a diet breadth index that identifies plants used in similar ways by Adelpha, pointing to potential plant traits that could facilitate or prevent plant-insect interactions. We find that diet breadth in Adelpha is not likely to change at different geographic scales, and that regional resource specialization was uncommon. Additionally, the diversification fueled by the switch to Rubiacae, appears to have led to some lowland-clade Adelpha species specializing on a restricted subset of host genera and species within Rubiaceae, as well as in Urticaceae. In contrast, the A. serpa-group shows generalization, with each species tending to feed on its own set of several unrelated plant families. Taken together, these results indicate that Rubiaceae and additional plant families appear as important ecological factors that have promoted adaptations in Adelpha and host plant family-level switches have not always had the same effect on diversification, corroborating the importance of Rubiaceae for this butterfly genus. Further research involving detailed phylogenies is needed to investigate associations between changes in diet breadth and speciation events, and test hypotheses of diet evolution.

This thesis provides an overview of Czech astronomy education both inside and outside of school environment and develops methods to explore its possible influence on science career decision. A mixed approach was chosen for the research. Based on the first qualitative part, hypotheses and specified research questions were formulated. Consequently, the hypotheses were examined using questionnaires distributed to students of several Czech universities. However, the data analysis showed a variable stronger than involvement in astronomy education - the breadth of science interest. Possible practical outcomes and recommendations for future research are discussed.

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Recent archaeological research within the American west, especially the Great Basin (e.g., Graf and Schmitt 2007), has perpetuated the notion of decreased residential mobility accompanied by increased diet breadth of hunter-gatherer groups during the Early Holocene. The earliest occupations at North Creek Shelter (NCS), a multicomponent site in south-central Utah, date to this time, specifically the Paleoarchaic (~10,000-9000 BP) and Early Archaic (~9000-7500 BP) periods. The zooarchaeological data from these levels were analyzed to determine whether Paleoarchaic occupations on the Colorado Plateau possessed greater residential mobility and narrower diet breadth than those of the Early Archaic, as they do in the Great Basin. However, upon examination of the NCS data, neither seems to be the case, or at least not to the dramatic degree observed to the west, as settlement and subsistence strategies remain fairly constant throughout the Early Holocene.

This dissertation consists of two essays investigating the trading by institutions and its impact on the stock market. In the first essay, I investigate why changes in institutional breadth predict return. I first show that changes in breadth are positively associated with abnormal returns over the following four quarters. I then demonstrate that this return predictability can be attributed to the information about the firms' future operating performance. When I examine different types of institutions independently, I find that the predictive power varies across the population of institutions. More specifically, institutions that follow active management style are better able to predict future returns than the passive institutions, and their predictive power appears to be associated with information about future earnings growth. These findings are consistent with the information hypothesis that changes in breadth of institutional ownership can predict return because they contain information about the fundamental value of firms. In the second essay, I examine institutional herding behavior and its impact on stock prices. I document that herds by institutions usually last for more than one quarter and that herds occur more frequently for small and medium size stocks. I find that after herds end, there are reversals in stocks returns for up to four quarters. The magnitude of reversals is positively related to the duration of herding, and negatively related to the price impact of current herding activity. This pattern in returns prevails for all sub-periods examined and is concentrated in small and medium size stocks. My findings suggest that institutional herding may destabilize stock prices.

The order of acquisition of various aspects of word knowledge is underexplored. Thus, this study examined learner performance with a number of aspects of word knowledge in an attempt to see whether they form an implicational scale in terms of an accuracy order. A total of 283 English as a Second Language students were tested on their knowledge of five aspects of word knowledge. Implicational scaling analysis was utilized to determine whether the components were scalable. The findings formed a scalable accuracy order. The accuracy order of the aspects of word knowledge examined in this study from easier to more difficult include: knowledge of the written form based on the spoken form, knowledge of the spoken form based on the written form, knowledge of the written form based on the meaning, knowledge of the spoken form based on the meaning, knowledge of spelling based on the spoken form. These findings suggest a number of implications for vocabulary acquisition as well as vocabulary teaching and learning.