8 resultados para enhancement of performance
em Digital Commons at Florida International University
Resumo:
In recent years, wireless communication infrastructures have been widely deployed for both personal and business applications. IEEE 802.11 series Wireless Local Area Network (WLAN) standards attract lots of attention due to their low cost and high data rate. Wireless ad hoc networks which use IEEE 802.11 standards are one of hot spots of recent network research. Designing appropriate Media Access Control (MAC) layer protocols is one of the key issues for wireless ad hoc networks. ^ Existing wireless applications typically use omni-directional antennas. When using an omni-directional antenna, the gain of the antenna in all directions is the same. Due to the nature of the Distributed Coordination Function (DCF) mechanism of IEEE 802.11 standards, only one of the one-hop neighbors can send data at one time. Nodes other than the sender and the receiver must be either in idle or listening state, otherwise collisions could occur. The downside of the omni-directionality of antennas is that the spatial reuse ratio is low and the capacity of the network is considerably limited. ^ It is therefore obvious that the directional antenna has been introduced to improve spatial reutilization. As we know, a directional antenna has the following benefits. It can improve transport capacity by decreasing interference of a directional main lobe. It can increase coverage range due to a higher SINR (Signal Interference to Noise Ratio), i.e., with the same power consumption, better connectivity can be achieved. And the usage of power can be reduced, i.e., for the same coverage, a transmitter can reduce its power consumption. ^ To utilizing the advantages of directional antennas, we propose a relay-enabled MAC protocol. Two relay nodes are chosen to forward data when the channel condition of direct link from the sender to the receiver is poor. The two relay nodes can transfer data at the same time and a pipelined data transmission can be achieved by using directional antennas. The throughput can be improved significant when introducing the relay-enabled MAC protocol. ^ Besides the strong points, directional antennas also have some explicit drawbacks, such as the hidden terminal and deafness problems and the requirements of retaining location information for each node. Therefore, an omni-directional antenna should be used in some situations. The combination use of omni-directional and directional antennas leads to the problem of configuring heterogeneous antennas, i e., given a network topology and a traffic pattern, we need to find a tradeoff between using omni-directional and using directional antennas to obtain a better network performance over this configuration. ^ Directly and mathematically establishing the relationship between the network performance and the antenna configurations is extremely difficult, if not intractable. Therefore, in this research, we proposed several clustering-based methods to obtain approximate solutions for heterogeneous antennas configuration problem, which can improve network performance significantly. ^ Our proposed methods consist of two steps. The first step (i.e., clustering links) is to cluster the links into different groups based on the matrix-based system model. After being clustered, the links in the same group have similar neighborhood nodes and will use the same type of antenna. The second step (i.e., labeling links) is to decide the type of antenna for each group. For heterogeneous antennas, some groups of links will use directional antenna and others will adopt omni-directional antenna. Experiments are conducted to compare the proposed methods with existing methods. Experimental results demonstrate that our clustering-based methods can improve the network performance significantly. ^
Resumo:
The purpose of this study is to identify the determinants of local officials' preferences of performance measures under the assumption that public officials' consensus on performance measures can enhance the accountability in public service delivery. This research consists of two steps: multiple case studies and a survey. The author conducted the case studies in five general-purpose municipalities in Florida, interviewing 25 local officials, attending community meetings, and reviewing relevant local documents. Based on the case studies and the relevant literature, a survey was developed and sent to 445 local officials in 67 general-purpose municipalities in Dade, Broward, and Palm Beach Counties, Florida. The findings of the case studies and the survey suggest that local officials' preferences of performance measures are influenced by their perception of utilities of performance measures and their desire to measure the achievement of organizational goals. The author concludes that a consensus among local officials for outcome-oriented performance measures is easier to achieve if a prospective performance measurement system is designed for reporting and management purposes rather than for budgeting purposes. ^
Resumo:
Current demands for accountability in education emphasize outcome-based program evaluation and tie program funding to individual student performance. As has been the case for elementary and secondary programs, demands for accountability have increased pressure on adult educators to show evidence of the benefits of their programs in order to justify their financial support. In Florida, recent legislation fundamentally changes the delivery of adult education in the state by establishing a performance-based funding system that is based on outcomes related to the retention, completion, and employment of program participants.^ A performance-based funding system requires an evaluation process that stresses outcome indicators over indicators that focus on program context or process. Although the state has adopted indicators of program quality to evaluate its adult education programs, these indicators focus mostly on program processes rather than student outcomes. In addition, the indicators are not specifically tied to workforce development outcomes, a priority to federal and local funding agents.^ Improving the accountability of adult education programs and defining the role of these programs in Florida's Workforce Development System has become a priority to policy makers across the state. Another priority has been to involve adult education practitioners in every step of this process.^ This study was conducted in order to determine what performance indicators, as judged by the directors and supervisors of adult education programs in the state of Florida, are important and feasible in measuring the quality and effectiveness of these programs. The results of the study indicated that, both statewide and by region, the respondents consistently gave the highest ratings on both importance and feasibility to the indicators of Program Context, which reflect the needs, composition, and structure of the programs, and to the indicators of Educational Gain, which reflect learner progress in the attainment of basic skills and competencies. In turn, the respondents gave the lowest ratings on both importance and feasibility to the indicators in the areas of Return on State's Investment, Efficiency, Retention, and Workforce Training. In general, the indicators that received high ratings for importance also received high ratings for feasibility. ^
Resumo:
The study described herein examined personality as a predictor of task and contextual performance. The Big Five personality dimensions (i.e., Neuroticism, Extraversion, Agreeableness, Openness to Experience, and Conscientiousness) were studied in relation to both task and contextual performance within an organization in the service industry. The situational factor, autonomy, was examined as a potential moderator for the hypothesized personality-contextual performance relationship. Hierarchical regression analyses indicated that Conscientiousness was a valid predictor of task performance, Neuroticism was a valid predictor of contextual performance, and Extraversion was a valid predictor of delinquent performance. However, results did not yield support for the moderating role of autonomy on the personality-contextual performance relationship. Nevertheless, job satisfaction did moderate the Openness to Experience-delinquent performance relationship. Practical implications of these results and suggestions for future research are discussed. ^
Resumo:
The purpose of this study was to assess the effect of performance feedback on Athletic Trainers’ (ATs) perceived knowledge (PK) and likelihood to pursue continuing education (CE). The investigation was grounded in the theories of “the definition of the situation” (Thomas & Thomas, 1928) and the “illusion of knowing,” (Glenberg, Wilkinson, & Epstein, 1982) suggesting that PK drives behavior. This investigation measured the degree to which knowledge gap predicted CE seeking behavior by providing performance feedback designed to change PK. A pre-test post-test control-group design was used to measure PK and likelihood to pursue CE before and after assessing actual knowledge. ATs (n=103) were randomly sampled and assigned to two groups, with and without performance feedback. Two independent samples t-tests were used to compare groups on the difference scores of the dependent variables. Likelihood to pursue CE was predicted by three variables using multiple linear regression: perceived knowledge, pre-test likelihood to pursue CE, and knowledge gap. There was a 68.4% significant difference (t101=2.72, p=0.01, ES=0.45) between groups in the change scores for likelihood to pursue CE because of the performance feedback (Experimental group=13.7% increase; Control group=4.3% increase). The strongest relationship among the dependent variables was between pre-test and post-test measures of likelihood to pursue CE (F2,102=56.80, p<0.01, r=0.73, R2=0.53). The pre- and post-test predictive relationship was enhanced when group was included in the model. In this model [YCEpost=0.76XCEpre-0.34 Xgroup+2.24+E], group accounted for a significant amount of unique variance in predicting CE while the pre-test likelihood to pursue CE variable was held constant (F3,102=40.28, p<0.01, r=0.74, R2=0.55). Pre-test knowledge gap, regardless of group allocation, was a linear predictor of the likelihood to pursue CE (F1,102=10.90, p=.01, r=.31, R2=.10). In this investigation, performance feedback significantly increased participants’ likelihood to pursue CE. Pre-test knowledge gap was a significant predictor of likelihood to pursue CE, regardless if performance feedback was provided. ATs may have self-assessed and engaged in internal feedback as a result of their test-taking experience. These findings indicate that feedback, both internal and external, may be necessary to trigger CE seeking behavior.
Resumo:
Do restaurant managers commonly use performance appraisals and, if so, how frequently anf for what purposes? The authors address these questions and review the restaurant industry in general.
Resumo:
The field emission measurements for the multistage structured nanotubes (i.e., thin-multiwall and single wall carbon nanotubes grown on multiwall carbon nanotubes) were carried out and a low turn-on field of ~0.45 V/ μm, high emission current of 450 μA at a field of IV/μm and a large field enhancement factor of ~26200 were obtained. The thin multiwall carbon nanotubes (thin-MWNTs) and single wall carbon nanotubes (SWNTs) were grown on the regular arrays of vertically aligned multi wall carbon nanotubes (MWNTs) on porous silicon substrate by Chemical Vapor Deposition (CVD) method. The thin-MWNTs and SWNTs grown on MWNTs in this way have a multistage structure which gives higher enhancement of the electric field and hence the electron field emission.
Resumo:
The purpose of this study was to assess the effect of performance feedback on Athletic Trainers’ (ATs) perceived knowledge (PK) and likelihood to pursue continuing education (CE). The investigation was grounded in the theories of “the definition of the situation” (Thomas & Thomas, 1928) and the “illusion of knowing,” (Glenberg, Wilkinson, & Epstein, 1982) suggesting that PK drives behavior. This investigation measured the degree to which knowledge gap predicted CE seeking behavior by providing performance feedback designed to change PK. A pre-test post-test control-group design was used to measure PK and likelihood to pursue CE before and after assessing actual knowledge. ATs (n=103) were randomly sampled and assigned to two groups, with and without performance feedback. Two independent samples t-tests were used to compare groups on the difference scores of the dependent variables. Likelihood to pursue CE was predicted by three variables using multiple linear regression: perceived knowledge, pre-test likelihood to pursue CE, and knowledge gap. There was a 68.4% significant difference (t101= 2.72, p=0.01, ES=0.45) between groups in the change scores for likelihood to pursue CE because of the performance feedback (Experimental group=13.7% increase; Control group= 4.3% increase). The strongest relationship among the dependent variables was between pre-test and post-test measures of likelihood to pursue CE (F2,102=56.80, p<0.01, r=0.73, R2=0.53). The pre- and post-test predictive relationship was enhanced when group was included in the model. In this model [YCEpost=0.76XCEpre-0.34 Xgroup+2.24+E], group accounted for a significant amount of unique variance in predicting CE while the pre-test likelihood to pursue CE variable was held constant (F3,102=40.28, p<0.01,: r=0.74, R2=0.55). Pre-test knowledge gap, regardless of group allocation, was a linear predictor of the likelihood to pursue CE (F1,102=10.90, p=.01, r=.31, R2=.10). In this investigation, performance feedback significantly increased participants’ likelihood to pursue CE. Pre-test knowledge gap was a significant predictor of likelihood to pursue CE, regardless if performance feedback was provided. ATs may have self-assessed and engaged in internal feedback as a result of their test-taking experience. These findings indicate that feedback, both internal and external, may be necessary to trigger CE seeking behavior.