Search results for "11"
showing 10 items of 17291 documents
A new approach for estimating a nonlinear growth component in multilevel modeling
2011
This study presents a new approach to estimation of a nonlinear growth curve component with fixed and random effects in multilevel modeling. This approach can be used to estimate change in longitudinal data, such as day-of-the-week fluctuation. The motivation of the new approach is to avoid spurious estimates in a random coefficient regression model due to the synchronized periodical effect (e.g., day-of-the-week fluctuation) appearing both in independent and dependent variables. First, the new approach is introduced. Second, a Monte Carlo simulation study is carried out to examine the functioning of the proposed new approach in the case of small sample sizes. Third, the use of the approac…
Depressive symptoms during adolescence: Do learning difficulties matter?
2011
To examine whether learning difficulties play a role in depressive symptoms, 658 Finnish adolescents were asked to complete scales for depression three times during the transition to post-comprehensive education. They also reported on their learning difficulties and feelings of inadequacy as a student. The results showed that learning difficulties prospectively predicted depressive symptoms. Moreover, the impact of learning difficulties was mediated via inadequacy as a student: learning difficulties predicted feelings of inadequacy as a student which, in turn, contributed to greater increases in depressive symptoms. Finally, gender moderated the association between learning difficulties an…
Accuracy, Coherence, and Discrepancy in Self and Other Reports: Moving Toward an Interactive Perspective of Organizational Dissent.
2013
The purpose of this study was twofold and involved examining the viability of using the Organizational Dissent Scale as an other-report instrument, and developing additional perceptual data related to dissent expression. A sample of 291 people completed survey questionnaire measures of organizational dissent. Equal-sized groups ( n = 97) completed either a self-report, a workplace colleague other-report, or an organizational outsider other-report. Results indicated the Organizational Dissent Scale performed reliably as an other-report, but it showed some tendency for social desirability. In addition, findings suggested that certain indicators of proximity to the dissenter reduced discrepan…
Surrogate-assisted evolutionary multiobjective shape optimization of an air intake ventilation system
2017
We tackle three different challenges in solving a real-world industrial problem: formulating the optimization problem, connecting different simulation tools and dealing with computationally expensive objective functions. The problem to be optimized is an air intake ventilation system of a tractor and consists of three computationally expensive objective functions. We describe the modeling of the system and its numerical evaluation with a commercial software. To obtain solutions in few function evaluations, a recently proposed surrogate-assisted evolutionary algorithm K-RVEA is applied. The diameters of four different outlets of the ventilation system are considered as decision variables. Fr…
Supporting Cyber Resilience with Semantic Wiki
2016
Cyber resilient organizations, their functions and computing infrastructures, should be tolerant towards rapid and unexpected changes in the environment. Information security is an organization-wide common mission; whose success strongly depends on efficient knowledge sharing. For this purpose, semantic wikis have proved their strength as a flexible collaboration and knowledge sharing platforms. However, there has not been notable academic research on how semantic wikis could be used as information security management platform in organizations for improved cyber resilience. In this paper, we propose to use semantic wiki as an agile information security management platform. More precisely, t…
Simultaneous optimization of harvest schedule and measurement strategy
2013
In many recent studies, the value of forest inventory information in the harvest scheduling has been examined. Usually only the profitability of measuring simultaneously all the stands in the area is examined. Yet, it may be more profitable to concentrate the measurement efforts to some subset of them. In this paper, the authors demonstrate that stochastic optimization can be used for defining the optimal measurement strategy simultaneously with the harvest decisions. The results show that without end-inventory constraints, it was most profitable to measure the stands that were just below the medium age. Measuring the oldest stands was not profitable at all. It turned out to be profitable t…
T9+HUD: Physical Keypad and HUD can Improve Driving Performance while Typing and Driving
2016
We introduce T9+HUD, a text entry method designed to decrease visual distraction while driving and typing. T9+HUD combines a physical 3x4 keypad on the steering wheel with a head-up-display (HUD) for projecting output on the windshield. Previous work suggests this may be a visually less demanding way to type while driving than the popular case which requires shifts of visual attention away from the road. We present a prototype design and report first results from a controlled evaluation in a driving simulator. While driving, the T9+HUD text entry rate was equal compared to a dashboard-mounted touchscreen device, but it reduced lane deviations by 70%. Furthermore, there was no significant di…
Voice traffic bicasting enhancements in mobile HSPA network
2014
This paper discusses methods for improving the effectiveness of delivering voice traffic over High-Speed Downlink Packet Access (HSDPA) network by employing transmission diversity with Single-Frequency Dual-Cell (SF-DC) Aggregation that is part of the Multiflow specification. SF-DC Aggregation allows the user to be served at the same time by two different cells. The enhancements discussed in the paper capitalize strongly on the availability of the composed Channel Quality Indication (CQI) feedback at both serving cells. According to the results obtained from the network simulations, the ability to select the better channel for each voice transmission significantly decreases the required tra…
Generalizability and Simplicity as Criteria in Feature Selection: Application to Mood Classification in Music
2011
Classification of musical audio signals according to expressed mood or emotion has evident applications to content-based music retrieval in large databases. Wrapper selection is a dimension reduction method that has been proposed for improving classification performance. However, the technique is prone to lead to overfitting of the training data, which decreases the generalizability of the obtained results. We claim that previous attempts to apply wrapper selection in the field of music information retrieval (MIR) have led to disputable conclusions about the used methods due to inadequate analysis frameworks, indicative of overfitting, and biased results. This paper presents a framework bas…
Acoustic detection and classification of river boats
2011
We present a robust algorithm to detect the arrival of a boat of a certain type when other background noises are present. It is done via the analysis of its acoustic signature against an existing database of recorded and processed acoustic signals. We characterize the signals by the distribution of their energies among blocks of wavelet packet coefficients. To derive the acoustic signature of the boat of interest, we use the Best Discriminant Basis method. The decision is made by combining the answers from the Linear Discriminant Analysis (LDA) classifier and from the Classification and Regression Trees (CART) that is also accompanied with an additional unit, called Aisles, that reduces fal…