Kinematic Graphs Research Articles

The effect of the native kinematics of the knee on the outcome following total knee arthroplasty.

The aim of this study was to investigate differences in pain, range of movement function and satisfaction at three months and one year after total knee arthroplasty (TKA) in patients with an oblique pattern of kinematic graph of the knee and those with a varus pattern. A total of 91 patients who underwent TKA were included in this retrospective study. Patients (59 women and 32 men with mean age of 68.7 years; 38.6 to 88.4) were grouped according to kinematic graphs which were generated during navigated TKA and the outcomes between the groups were compared. The graphs were varus in 50 patients (55%), oblique in 19 (21%), neutral in 17 (18.5%) and valgus in five (5.5%). After adjustment for pre-operative scores and gender, compared with patients with varus knee kinematics, patients with an oblique kinematic graph had a poorer outcome with lower Knee Society scores at three months (9.2 points, p = 0.038). We found four distinct kinematic graphs in knees and that patients with an oblique graph have a poorer outcome in the short-term after TKA. Cite this article: Bone Joint J 2016;98-B:1471-8.

A new user friendly visual environment for breast MRI data analysis

Introduction In recent years, there has been a great effort for the exploitation of powerful computer systems in order to support clinical decisions, the so-called CDSS (Clinical Desicion Support Systems). After processing imaging data in an automatic way they can provide useful diagnostic information facilitating like this clinical decisions. Purpose This study demonstrates the advantages of a newly developed friendly visual CDSS environment for Breast MRI Data Analysis, the co-called BreDAn. This software process all dynamic MRI data prior and post contrast medium injection generating kinematic graphs, color maps of signal increase and decrease and finally detecting high risk breast areas. The great advantage of BreDAn is the automation of the radiodiagnostic process in a reliable manner. Materials and methods BreDAn involves a series of steps of MRI Breast data processing, such as data initialization, windowing, intensity filter, intensity curve slope filter, color fragment filter and data display. It has been tested and evaluated using 534 MRI data sets (522 F, age group 31–79 y and 12 M, 55–68 y). A GE Signa HDxt 1.5 Tesla system was used throughout all MRI scans. A description of the MRI protocol is given. Results Out of the 534 cases studied, 9.55% of them found to be pathological and 90.45% were non-malignant. All automatically generated results by BreDAn were compared by radiologist’s diagnosis and found to be in agreement. BreDAn in practice simulates the radiological diagnostic methodology. Conclusion This study illustrates the advantages of BreDAn, a user friendly visual environment for MRI Breast data analysis, which have been tested thoroughly and validated successfully.

Development of Kinematic Graphs of Median Nerve during Active Finger Motion: Implications of Smartphone Use.

BackgroundCertain hand activities cause deformation and displacement of the median nerve at the carpal tunnel due to the gliding motion of tendons surrounding it. As smartphone usage escalates, this raises the public’s concern whether hand activities while using smartphones can lead to median nerve problems.ObjectiveThe aims of this study were to 1) develop kinematic graphs and 2) investigate the associated deformation and rotational information of median nerve in the carpal tunnel during hand activities.MethodsDominant wrists of 30 young adults were examined with ultrasonography by placing a transducer transversely on their wrist crease. Ultrasound video clips were recorded when the subject performing 1) thumb opposition with the wrist in neutral position, 2) thumb opposition with the wrist in ulnar deviation and 3) pinch grip with the wrist in neutral position. Six still images that were separated by 0.2-second intervals were then captured from the ultrasound video for the determination of 1) cross-sectional area (CSA), 2) flattening ratio (FR), 3) rotational displacement (RD) and 4) translational displacement (TD) of median nerve in the carpal tunnel, and these collected information of deformation, rotational and displacement of median nerve were compared between 1) two successive time points during a single hand activity and 2) different hand motions at the same time point. Finally, kinematic graphs were constructed to demonstrate the mobility of median nerve during different hand activities.ResultsPerforming different hand activities during this study led to a gradual reduction in CSA of the median nerve, with thumb opposition together with the wrist in ulnar deviation causing the greatest extent of deformation of the median nerve. Thumb opposition with the wrist in ulnar deviation also led to the largest extent of TD when compared to the other two hand activities of this study. Kinematic graphs showed that the motion pathways of median nerve during different hand activities were complex.ConclusionWe observed that the median nerve in the carpal tunnel was rotated, deformed and displaced during the hand activities that people may be performed when using a smartphone, suggesting an increased risk of carpal tunnel syndrome (CTS). In addition, the kinematic graphs of median nerve developed in the present study provide new clues for further studies on the pathophysiology of CTS, and alerting smartphone users to establish proper postural habits when using handheld electronic devices.

Graphic Comprehension and Interpretation Skills of Preservice Teachers with Different Learning Approaches in a Technology-Aided Learning Environment

A one-group quasi-experimental design and survey methodology were used to investigate the effect of virtual laboratory practices on preservice teachers’ (N = 29) graphic comprehension and interpretation skills with different learning approaches. Pretest and posttest data were collected with the Test of Understanding Kinematic Graphs. The Learning Approaches Scale was administered to the preservice science teachers to determine if they used an in-depth, superficial, or strategic approach. These data were analyzed using non-parametric statistics. The effect of virtual laboratory practices on these preservice teachers’ graphic comprehension and interpretation skills was evaluated, and a significant pretest–posttest gain for “Selecting the graphic related to the explanation of movement” was found. Suggestions are made to address the effects of teaching models and technology-integrated learning environments on students’ learning approach in science courses at different levels of education.

An approach to automatic adaptation of assembly models

Adaptation plays a fundamental role in case-based design. However, after decades of efforts, automatic adaptation is still an open issue. In works of case-based design, a designer usually chooses a start-up product model (a candidate model) of moderate complexity based on a query model possessing primary new design requirements (kinematic semantics and geometry), then achieves the target design by adapting the candidate model according to the new design requirements and human interventions are often indispensable. To smartly adapt the candidate model to fit the new design requirements, a novel approach to automatic adaptation of assembly models is proposed in this paper. First, in order to effectively identify the corresponding links and interfaces between two non-preregistered assembly models as relevant elements, an attributed kinematic graph is put forward and adopted. Second, based on the attributed kinematic graph, the kinematic semantics of the candidate model is automatically adapted to that of the query model. Third, through performing interface layout transferring, the geometry of the candidate model is automatically adapted to that of the query model based on the corresponding links and interfaces. A prototype system is also implemented to verify the effectiveness of the proposed approach.

Pre-service Science Teachers’ Understanding of One-Dimensional Motion Graphs in the Kinematic Context

The aim of this study is to examine pre-service science teachers’ understanding of graphs in kinematic context. This study focuses on one-dimensional motion graphs. The participants in this study are 115 pre-service science teachers. The data of the study was gathered with an open-ended questionnaire. The case study approach was used in this study. The qualitative data is analysed using thematic content analysis. The results of this study reveal that more than half of the participants cannot adequately understand the one-dimensional motion graphs. These findings suggest that pre-service science teachers’ instructors should be aware of their students’ difficulties in understanding of kinematic graphs. Furthermore, teaching modules which will promote the pre-service science teachers’ understanding of kinematic graphs are designed and implemented.

The Maiden Voyage of a Kinematics Robot

In a Montessori preschool classroom, students work independently on tasks that absorb their attention in part because the apparatus are carefully designed to make mistakes directly observable and limit exploration to one aspect or dimension. Control of error inheres in the apparatus itself, so that teacher intervention can be minimal.1 Inspired by this example, I created a robotic kinematics apparatus that also shapes the inquiry experience. Students program the robot by drawing kinematic graphs on a computer and then observe its motion. Exploration is at once limited to constant velocity and constant acceleration motion, yet open to complex multi-segment examples difficult to achieve in the lab in other ways. The robot precisely and reliably produces the motion described by the students' graphs, so that the apparatus itself provides immediate visual feedback about whether their understanding is correct as they are free to explore within the hard-coded limits. In particular, the kinematic robot enables hands-on study of multi-segment constant velocity situations, which lays a far stronger foundation for the study of accelerated motion. When correction is anonymous—just between one group of lab partners and their robot—students using the kinematic robot tend to flow right back to work because they view the correction as an integral part of the inquiry learning process. By contrast, when correction occurs by the teacher and/or in public (e.g., returning a graded assignment or pointing out student misconceptions during class), students all too often treat the event as the endpoint to inquiry. Furthermore, quantitative evidence shows a large gain from pre-test to post-test scores using the Test of Understanding Graphs in Kinematics (TUG-K).

On the definition of an kinematic hardening effect graph for sheet metal forming process simulations

The objective of this work is to develop a kinematic hardening effect graph (KHEG) which can be used to evaluate the effect of kinematic hardening on the model accuracy of numerical sheet metal forming simulations and this without the need of complex material characterisation. The virtual manufacturing process design and optimisation depends on the accuracy of the constitutive models used to represent material behaviour. Under reverse strain paths the Bauschinger effect phenomenon is modelled using kinematic hardening models. However, due to the complexity of the experimental testing required to characterise this phenomenon in this work the KHEG is presented as an indicator to evaluate the potential benefit of carrying out these tests. The tool is validated with the classic three point bending process and the U-channel width drawbead process. In the same way, the capability of the KHEG to identify effects in forming processes that do not include forming strain reversals is identified.

Motion sensors in mathematics teaching: learning tools for understanding general math concepts?

Incorporating technology tools into the mathematics classroom adds a new dimension to the teaching of mathematics concepts and establishes a whole new approach to mathematics learning. In particular, gathering data in a hands-on and real-time method helps classrooms coming alive. The focus of this paper is on bringing forward important mathematics concepts such as functions and rate of change with the motion detector. Findings from the author's studies suggest that the motion detector can be introduced from a very early age and used to enliven classes at any level. Using real-world data to present the main functions invites an experimental approach to mathematics and encourages students to engage actively in their learning. By emphasizing learning experiences with computer-based motion detectors and aiming to involve students in mathematical representations of real-world phenomena, six learning activities, which were developed in previous research studies, will be presented. Students use motion sensors to collect physical data that are graphed in real time and then manipulate and analyse them. Because data are presented in an immediately understandable graphical form, students are allowed to take an active role in their learning by constructing mathematical knowledge from observation of the physical world. By utilizing a predict–observe–explain format, students learn about slope, determining slope and distance vs. time graphs through motion-filled activities. Furthermore, exploring the meaning of slope, viewed as the rate of change, students acquire competencies for reading, understanding and interpreting kinematics graphs involving a multitude of mathematical representations. Consequently, the students are empowered to efficiently move among tabular, graphical and symbolic representation to analyse patterns and discover the relationships between different representations of motion. In fact, there is a need for further research to explore how mathematics teachers can integrate motion sensors into their classrooms.

Students’ approaches when dealing with kinematics graphs explored by eye-tracking research method

The paper is focused on students graphing, particularly graphing in kinematics. The main interest of the survey was in different approaches of different students group. Particularly, groups of students who performed the test the best and the worst and groups of students who answered a task correctly or incorrectly. Altogether 26 students participated in the survey from high schools and colleges. 7 tasks mostly adopted from TUGK test by Beichner (1994) were used for testing. Eye tracker research method was used and data were analysed qualitatively based on heat maps of number of fixations. We identified different numbers of fixations distributed among areas of tasks for the groups of students. Especially in most cases “Best” students did not show the same pattern like students who answered a task correctly. This indicates some general different approaches which are used by the “Best” group students. Particularly, they more frequently fixated instructions in contrast to the rest areas of the graph. They tended to judge the whole curve of a graph. Students who answered correctly or belonged to the group “Worst” tend to fixate more often the same point within the area of the task. These results suggest some hypothesis for further quantitative research.

Efficient enforcement of hard articulation constraints in the presence of closed loops and contacts

AbstractIn rigid body simulation, one must distinguish between contacts (so‐called unilateral constraints) and articulations (bilateral constraints). For contacts and friction, iterative solution methods have proven most useful for interactive applications, often in combination with Shock‐Propagation in cases with strong interactions between contacts (such as stacks), prioritizing performance and plausibility over accuracy. For articulation constraints, direct solution methods are preferred, because one can rely on a factorization with linear time complexity for tree‐like systems, even in ill‐conditioned cases caused by large mass‐ratios or high complexity. Despite recent advances, combining the advantages of direct and iterative solution methods wrt. performance has proven difficult and the intricacy of articulations in interactive applications is often limited by the convergence speed of the iterative solution method in the presence of closed kinematic loops (i.e. auxiliary constraints) and contacts. We identify common performance bottlenecks in the dynamic simulation of unilateral and bilateral constraints and are able to present a simulation method, that scales well in the number of constraints even in ill‐conditioned cases with frictional contacts, collisions and closed loops in the kinematic graph. For cases where many joints are connected to a single body, we propose a technique to increase the sparsity of the positive definite linear system. A solution to these bottlenecks is presented in this paper to make the simulation of a wider range of mechanisms possible in real‐time without extensive parameter tuning.

The use of intuitive rules in interpreting students’ difficulties in reading and creating kinematic graphs

The ability to form and interpret kinematic graphs is an essential skill for students studying physics. The literature, however, details a variety of students’ difficulties in this regard. The present article discusses how intuitive rules theory (Stavy and Tirosh. Int. J. Sci. Educ. 18, 653 (1996)) can be applied as a conceptual framework for understanding why some of these difficulties may occur. It suggests, moreover, that explicit teaching regarding students’ use of intuitive rules in interpreting kinematic graphs may deepen students’ general understanding of graphs in physics.

Exploring one aspect of pedagogical content knowledge of teaching assistants using the test of understanding graphs in kinematics

The Test of Understanding Graphs in Kinematics (TUG-K) is a multiple-choice test developed by Beichner in 1994 to assess students' understanding of kinematics graphs. Many of the items on the TUG-K have strong distractor choices which correspond to students' common difficulties with kinematics graphs. Instruction is unlikely to be effective if instructors do not know the common difficulties of introductory physics students and explicitly take them into account in their instructional design. We evaluate one aspect of the pedagogical content knowledge of first-year physics graduate students enrolled in a teaching assistant training course related to topics covered in the TUG-K. In particular, for each item on the TUG-K, the graduate students were asked to identify which incorrect answer choice they thought would be most commonly selected by introductory physics students if they did not know the correct answer after instruction in relevant concepts. We used the graduate student data and the data from Beichner's original paper for introductory physics students (which was collected from over 500 college and high school students) to assess this aspect of the pedagogical content knowledge of the graduate students, i.e., knowledge of student difficulties related to kinematics graphs as they are revealed by the TUG-K. We find that, although the graduate students, on average, performed better than random guessing at identifying introductory student difficulties on the TUG-K, they did not identify many common difficulties that introductory students have with graphs in kinematics. In addition, we find that the ability of graduate students to identify the difficulties of introductory students is context dependent and that discussions among the graduate students improved their understanding of student difficulties related to kinematics graphs. Moreover, we find that the ability of American graduate students in identifying common student difficulties is comparable with that of foreign graduate students.

Assessment of gait kinematic graphs pathology differences, among hemiplegic, diplegic and quadriplegic CP patients using asymmetry vs. deviation plots

Assessment of gait kinematic graphs pathology differences, among hemiplegic, diplegic and quadriplegic CP patients using asymmetry vs. deviation plots

A new user-friendly visual environment for breast MRI data analysis

In this paper a novel, user friendly visual environment for Breast MRI Data Analysis is presented (BreDAn). Given planar MRI images before and after IV contrast medium injection, BreDAn generates kinematic graphs, color maps of signal increase and decrease and finally detects high risk breast areas. The advantage of BreDAn, which has been validated and tested successfully, is the automation of the radiodiagnostic process in an accurate and reliable manner. It can potentially facilitate radiologists’ workload.

An algorithm for the construction of generalized kinematic chains

One of the major steps in the creative, conceptual, or structural synthesis of mechanical devices is to generate the necessary atlas of kinematic graphs or chains. The atlas of generalized kinematic chains includes the atlas of kinematic chains for mechanisms and the atlas of rigid chains for structures (clamping devices). This study provides an enumeration algorithm for constructing various atlases of generalized kinematic chains based on link assortments, Robinson's method, generating function of planar blocks, Euler's formula, and graph theory. Examples are provided. And, the numbers of generalized kinematic chains with up to twelve links are listed.

Function plot response: A scalable system for teaching kinematics graphs

Understanding and interpreting graphs are essential skills in all sciences. While students are mostly proficient in plotting given functions and reading values off graphs, they frequently lack the ability to construct and interpret graphs in a meaningful way. Students can use graphs as representations of value pairs, but often fail to interpret them as the representation of functions, and mostly fail to use them as representations of physical reality. Working with graphs in classroom settings has been shown to improve student abilities with graphs, particularly when the students can interact with them. We introduce a novel problem type in an online homework system, which requires students to construct the graphs themselves in free form, and requires no hand-grading by instructors. Initial experiences using the new problem type in an introductory physics course are reported.

COMPARISON OF STUDENT UNDERSTANDING OF LINE GRAPH SLOPE IN PHYSICS AND MATHEMATICS

This study gives an insight into the differences between student understanding of line graph slope in the context of physics (kinematics) and mathematics. Two pairs of parallel physics and mathematics questions that involved estimation and interpretation of line graph slope were constructed and administered to 114 Croatian second year high school students (aged 15 to 16 years). Each pair of questions referred to the same skill in different contexts—one question in the context of mathematics and the other in the context of kinematics. A sample of Croatian physics teachers (N = 90) was asked to rank the questions according to their expected difficulty for second year high school students. The prevalent ranking order suggests that most physics teachers expected mathematics questions to be more difficult for students than the parallel physics questions. Contrary to the prevalent teachers’ expectations, students succeeded better on mathematics than on physics questions. The analysis of student answers and explanations suggests that the lack of mathematical knowledge is not the main reason for student difficulties with graphs in kinematics. It appears that the interpretation of the meaning of line graph slope in a physics context presents the largest problem for students. However, students also showed problems with the understanding of the concept of slope in a mathematical context. Students exhibited slope/height confusion in both contexts, but much more frequently in the context of physics than in the context of mathematics.

A laboratory activity on the eddy current brake

The aim of this paper is to introduce a simple and low-cost experimental setup that can be used to study the eddy current brake, which considers the motion of a sliding magnet on an inclined conducting plane in terms of basic physical principles. We present a set of quantitative experiments performed to study the influence of the geometrical and electromagnetic properties of the magnet on the magnetic drag force. This video-based experiment is ideal for the study of kinematic graphs and the application of Newton's laws. Video motion analysis software enables students to make precise measurements of the magnet's position at incremental times during its motion, thus allowing them to quantify electromagnetic induction phenomena. The equipment needed for this experiment and data collection software are present in most physics teaching laboratories or are inexpensive and available.

Isomorphism Identification of Kinematic Chain Topology Embryonic Graphs

Isomorphism identification of topology embryonic graphs is a key link in plane parallel mechanism synthesis methods based on embryonic graph.Aiming at kinematic chains topology embryonic graph without binary links,the problem of isomorphism identification among them is solved.Topology embryonic graph has unique feature against topology graph.Because there aren't binary vertices in limbs of topology embryonic graph,relation among vertices are largely relative position among them.According to the feature of topology embryonic graph,the matrix of path number among any vertices of topology embryonic graph is set up from the classical theory of adjacency matrix about graph.The items of the path number matrix are arranged into path array according to certain rule.The isomorphic condition for topology embryonic graphs is demonstrated.Topology embryonic graphs are identified if they are isomorphic by second order path array when degree sequence and first order path array are same.Examples are given to illustrate identification procedure and specific application.Solution to the problem of isomorphism identification of topology embryonic graph not only lays the foundation for type synthesis based on embryonic graph,but also there is universal significance for isomorphism identification of some kinematic chain topology graphs.