Activities for Students: As the Ball Rolls: A Quadratic Investigation Using Multiple Representations

2009 ◽  
Vol 103 (1) ◽  
pp. 62-68
Author(s):  
Kathleen Cage Mittag ◽  
Sharon Taylor

Using activities to create and collect data is not a new idea. Teachers have been incorporating real-world data into their classes since at least the advent of the graphing calculator. Plenty of data collection activities and data sets exist, and the graphing calculator has made modeling data much easier. However, the authors were in search of a better physical model for a quadratic. We wanted students to see an actual parabola take shape in real time and then explore its characteristics, but we could not find such a hands-on model.

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 507
Author(s):  
Piotr Białczak ◽  
Wojciech Mazurczyk

Malicious software utilizes HTTP protocol for communication purposes, creating network traffic that is hard to identify as it blends into the traffic generated by benign applications. To this aim, fingerprinting tools have been developed to help track and identify such traffic by providing a short representation of malicious HTTP requests. However, currently existing tools do not analyze all information included in the HTTP message or analyze it insufficiently. To address these issues, we propose Hfinger, a novel malware HTTP request fingerprinting tool. It extracts information from the parts of the request such as URI, protocol information, headers, and payload, providing a concise request representation that preserves the extracted information in a form interpretable by a human analyst. For the developed solution, we have performed an extensive experimental evaluation using real-world data sets and we also compared Hfinger with the most related and popular existing tools such as FATT, Mercury, and p0f. The conducted effectiveness analysis reveals that on average only 1.85% of requests fingerprinted by Hfinger collide between malware families, what is 8–34 times lower than existing tools. Moreover, unlike these tools, in default mode, Hfinger does not introduce collisions between malware and benign applications and achieves it by increasing the number of fingerprints by at most 3 times. As a result, Hfinger can effectively track and hunt malware by providing more unique fingerprints than other standard tools.


Author(s):  
Martyna Bogacz ◽  
Stephane Hess ◽  
Chiara Calastri ◽  
Charisma F. Choudhury ◽  
Alexander Erath ◽  
...  

The use of virtual reality (VR) in transport research offers the opportunity to collect behavioral data in a controlled dynamic setting. VR settings are useful in the context of hypothetical situations in which real-world data does not exist or in situations which involve risk and safety issues making real-world data collection infeasible. Nevertheless, VR studies can contribute to transport-related research only if the behavior elicited in a virtual environment closely resembles real-world behavior. Importantly, as VR is a relatively new research tool, the best-practice with regards to the experimental design is still to be established. In this paper, we contribute to a better understanding of the implications of the choice of the experimental setup by comparing cycling behavior in VR between two groups of participants in similar immersive scenarios, the first group controlling the maneuvers using a keyboard and the other group riding an instrumented bicycle. We critically compare the speed, acceleration, braking and head movements of the participants in the two experiments. We also collect electroencephalography (EEG) data to compare the alpha wave amplitudes and assess the engagement levels of participants in the two settings. The results demonstrate the ability of VR to elicit behavioral patterns in line with those observed in the real-world and indicate the importance of the experimental design in a VR environment beyond the choice of audio-visual stimuli. The findings will be useful for researchers in designing the experimental setup of VR for behavioral data collection.


2013 ◽  
Vol 34 (3) ◽  
pp. 133-148 ◽  
Author(s):  
François Pomerleau ◽  
Francis Colas ◽  
Roland Siegwart ◽  
Stéphane Magnenat

Author(s):  
Lutz Oettershagen ◽  
Petra Mutzel

AbstractThe closeness centrality of a vertex in a classical static graph is the reciprocal of the sum of the distances to all other vertices. However, networks are often dynamic and change over time. Temporal distances take these dynamics into account. In this work, we consider the harmonic temporal closeness with respect to the shortest duration distance. We introduce an efficient algorithm for computing the exact top-k temporal closeness values and the corresponding vertices. The algorithm can be generalized to the task of computing all closeness values. Furthermore, we derive heuristic modifications that perform well on real-world data sets and drastically reduce the running times. For the case that edge traversal takes an equal amount of time for all edges, we lift two approximation algorithms to the temporal domain. The algorithms approximate the transitive closure of a temporal graph (which is an essential ingredient for the top-k algorithm) and the temporal closeness for all vertices, respectively, with high probability. We experimentally evaluate all our new approaches on real-world data sets and show that they lead to drastically reduced running times while keeping high quality in many cases. Moreover, we demonstrate that the top-k temporal and static closeness vertex sets differ quite largely in the considered temporal networks.


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