The effects of causality,response alternatives,and context continuity on hypothesis testing reasoning

Two selection hypothesis testing tasks and nine evaluation hypothesis testing tasks which varied systematically with respect to causality, response alternatives, and context continuity were administered to two samples of adults to determine the effects of those variables and to determine the degree to which subjects (Ss) reasoned with material conditional, material biconditional, partial, or partial plus biconditional connectives. On the causal selection task the majority of Ss responded “yes” to all four instances, while on the evaluation tasks all three variables were found to affect performance. Ss responded consistently with the material biconditional connective especially when the tasks called for them to state their expectations or were written with context continuity. Results were interpreted to support the hypothesis that hypothesis testing reasoning in causal contexts begins with the material biconditional connective and involves schemata of controlling variables, probability, and correlations. A strictly “logical” falsification strategy is not viewed as operative. Implications for teaching students how to effectively test hypotheses in science classes are discussed.     

Connecting Science and Mathematics: The Nature of Proof and Disproof in Science and Mathematics

Disagreements exist among textbook authors, curriculum developers, and even among science and mathematics educators/researchers regarding the meanings and roles of several key nature-of-science (NOS) and nature-of-mathematics (NOM) terms such as proof, disproof, hypotheses, predictions, theories, laws, conjectures, axioms, theorems, and postulates. To assess the extent to which these disagreements may exist among high school science and mathematics teachers, a 14-item survey of the meanings and roles of the above terms was constructed and administered to a sample of science and mathematics teachers. As expected, the science teachers performed better than the mathematics teachers on the NOS items (44.1 versus 24.7%, respectively) and the mathematics teachers performed better than the science teachers on the NOM items (59.0 versus 26.1%, respectively). Nevertheless, responses indicated considerable disagreement and/or lack of understanding among both groups of teachers concerning the meanings/roles of proof and disproof and several other key terms. Therefore it appears that these teachers are poorly equipped to help students gain understanding of these key terms. Classroom use of the If/and/then/Therefore pattern of argumentation, which is employed in this paper to explicate the hypothesis/conjecture testing process, might be a first step toward rectifying this situation.     

Three-dimensional kinematic analysis and power output of elite flat-water kayakers

The purpose was to examine power output and three-dimensional (3D) kinematic variables in the upper limbs, lower limbs and trunk in elite flat-water kayakers during kayak ergometer paddling. An additional purpose was to analyse possible changes in kinematics with increased intensity and differences between body sides. Six male and four female international level flat-water kayakers participated. Kinematic and kinetic data were collected during three tasks; low (Int_L), high (Int_H) and maximal (Int_M) intensities. No differences were observed in any joint angles between body sides, except for shoulder abduction. Significantly greater range of motion (RoM) values were observed for Int_H compared to Int_L and for Int_M compared to Int_L in trunk and pelvis rotation, and in hip, knee and ankle flexion. The mean maximal power output was 610 ± 65 and 359 ± 33 W for the male and female athletes, respectively. The stroke frequencies were significantly different between all intensities (Int_L 59.3 ± 6.3; Int_H 108.0 ± 6.8; Int_M 141.7 ± 18.4 strokes/min). The results showed that after a certain intensity level, the power output must be increased by other factors than increasing the joint angular RoM. This information may assist coaches and athletes to understand the relationship between the movement of the kayaker and the paddling power output.     

Adaptive and online network intrusion detection system using clustering and Extreme Learning Machines

Despite the large volume of research conducted in the field of intrusion detection, finding a perfect solution of intrusion detection systems for critical applications is still a major challenge. This is mainly due to the continuous emergence of security threats which can bypass the outdated intrusion detection systems. The main objective of this paper is to propose an adaptive design of intrusion detection systems on the basis of Extreme Learning Machines. The proposed system offers the capability of detecting known and novel attacks and being updated according to new trends of data patterns provided by security experts in a cost-effective manner.     

Machine learning for people detection in guidance functionality of enabling health applications by means of cascaded SVM classifiers

Electronic assistance devices for visually impaired people often require pedestrian detection functionality. Due to the fact that these devices have only low computational processing capabilities, it is necessary to use realtime algorithms that meet these requirements.We thus propose application of a cascaded support vector machine (SVM) classifier with linear and combined cascading of SVMs based on histogram of oriented gradients (HOGs) and Fisher score preselection. Proposed algorithms are evaluated on the basis of the INRIA database and compared to the state of the art procedure with HOG-features in combination with a standard SVM.     

What are the relative effects of reasoning ability and prior knowledge on biology achievement in expository and inquiry classes?

What factor(s) influence the likelihood a student will succeed in college biology? Some researchers have found the primary determinant to be the student's prior knowledge of biology, while others have found it to be reasoning ability. Perhaps the ability of these factors to predict achievement depends on the instructional method employed. Expository instruction focuses primarily on facts and concepts. Therefore, perhaps the best predictor of achievement in expository classes is domain-specific prior knowledge. Inquiry instruction focuses more on how science is done, i.e., on scientific processes; therefore, perhaps the best predictor in inquiry classes is reasoning ability. This study was designed to test these hypotheses. Students enrolled in a nonmajors community college biology course were pretested to determine reasoning ability and prior knowledge. The number of previous biology courses was also recorded as an indicator of prior knowledge. After a semester of either expository or inquiry (learning-cycle) instruction, students took a comprehensive final examination. Reasoning ability but not prior knowledge or number of previous biology courses accounted for a significant amount of variance in final examination score in both instructional methods and with semester examination and quiz scores in inquiry classes. This suggests that reasoning ability limits achievement more than prior knowledge among these biology students, whether they are enrolled in expository or inquiry classes. Reasoning ability explained more of the variance in final examination scores for students enrolled in expository classes (18.8%) than in inquiry classes (7.2%). The reason for this is not clear, but significant improvements in reasoning were found in the inquiry but not in the expository classes. These improvements were accompanied by significant differences in achievement in the inquiry classes. Perhaps the reasoning improvement facilitated the better and more equal achievement for students in the inquiry classes, thus reducing the correlation between initial reasoning ability and final achievement. © 1998 John Wiley & Sons, Inc. J Res Sci Teach 35: 89-103, 1998.