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Experimental evaluation of OSB-faced structural insulated panels subject to blast loads
No full textThis paper reports the results of an experimental program to quantify the blast protection provided by as-built and strengthened structural insulated panels (SIP) subjected to short-duration uniform pressure loads in a blast load simulator facility. SIPs are used in residential and light-commercial buildings. The SIPs used in this study had an overall thickness of 117 mm with 11 mm thick oriented strand board (OSB) facers and a 95-mm thick polyurethane closed-cell foam core. This type of sandwich panel provides improved energy efficiency and reduced construction time. A total of eight panels were tested in four different configurations: (1) as-built SIP design with standard connections, (2) as-built SIP design with strengthened roof connection, (3) flexural strengthened SIP using galvanized steel straps with strengthened roof connections, and (4) flexural strengthened SIP using fiber reinforced polymer (FRP) wallboard with strengthened roof connections. Each panel in this experimental program was 1.2 m by 2.4 m and was tested independently. The panels were subjected to two to five incrementally increasing pressure-impulse combinations. The first was a low pressure shot to verify the elastic performance of the SIP. The magnitude of the pressure-impulse combination for the subsequent shots increased until ultimate failure of the panels. By strengthening the roof connection, the as-built panels withstood a 27% larger impulse. The steel strap and FRP flexural strengthening with the strengthened roof connections led to a three-fold and five-fold increase in impulse resisted, respectively, when compared to the as-built SIP with standard connections. The results of the experimental study were validated using single-degree-of-freedom (SDOF) models. The SDOF analysis included an elastic resistance function for each panel configuration. The SDOF analysis estimated displacements 9% larger than the experimental results on average. The analytical model was more conservative for the lower pressure shots indicating that one-way behavior of SIPs subjected to short duration uniform pressure loads may be reasonably estimated using fundamental bending mechanics. Overall, the results of the experimental and analytical study indicated simple strengthening methods may be used to significantly improve the blast resistance of SIPs
GPS and IMU Fusion for Human Gait Estimation
No full textThis paper proposes a framework for fusing information coming from an independent inertial measurement unit (IMU) and global positioning system (GPS) to deliver robust estimation of human gait. Because these two sensors provide very different kinds of data at different scales and frequencies, a novel approach which fuses global trajectory estimates and back-propagates this information to correct step vectors is put forth here. In several high-fidelity simulations, the proposed technique is shown to improve step estimation error up to 40% in comparison with an IMU-only approach. This work has implications for not only in-the-field biomechanics research, but also cooperative field robotic systems where it may be critical to accurately monitor a person’s position and state in real-time
Towards Finding the Optimum Position in the Visual Field for a Head Worn Display Used for Task Guidance with Non-registered Graphics
No full textWhere should a HWD be placed in a user’s visual field? We present two studies that compare comfort, preference, task efficiency and accuracy for various HWD positions. The first study offsets a 9.2° horizontal field-of-view (FOV) display temporally (toward the ear) from 0° to 30° in 10° steps. 30° proves too uncomfortable while 10° is the most preferred position for a simple button-pushing game, corroborating results from previous single-task reading experiments. The second experiment uses a Magic Leap One to compare 10° x 10° FOV interfaces centered at line-of-sight, temporally offset 15° (center-right), inferiorly offset 15° (bottom-center), and offset in both directions (bottom-right) for an order picking task. The bottom-right position proved worst in terms of accuracy and several subjective metrics when compared to the line-of-sight position
Integrating ‘FORTE’ to Enhance Speaking Confidence in the Arabic Classroom
Get PDFThis research project sought to enhance students’ ability to “perform” in a second language (SL) through a modification to course instruction through an emphasis on ‘FORTE’ (Family, Occupation, Recreation, Travel, Education). This study was conducted over the Spring semester of 2021 across two classroom sections of LA204 - Basic Arabic II (n=24). The objective of this research was to determine the extent to which modifications to course instruction methods affect students’ level of confidence in speaking Arabic as measured by survey responses, instructor observation, and verbal feedback. Additionally, the research sought to determine if ability to perform in a second language demonstrated an increased interest in pursuing additional language study. Over the course of the semester, students were introduced to specific material relating to FORTE and practiced this material during the ‘warm-up’ period of the class (first 10 to 15 minutes). While the findings show significant increase in reported confidence in student speaking ability, more research is required to determine what effect this may have on enthusiasm for continued Arabic study
Cybersecurity Anomaly Detection in Adversarial Environments
No full textThe proliferation of interconnected battlefield information-sharing devices, known as the Internet of Battlefield Things (IoBT), introduced several security challenges. Inherent to the IoBT operating environment is the practice of adversarial machine learning, which attempts to circumvent machine learning models. This work examines the feasibility of cost-effective unsupervised learning and graph-based methods for anomaly detection in the network intrusion detection system setting, and also leverages an ensemble approach to supervised learning of the anomaly detection problem. We incorporate a realistic adversarial training mechanism when training supervised models to enable strong classification performance in adversarial environments. The results indicate that the unsupervised and graph-based methods were outperformed in detecting anomalies (malicious activity) by the supervised stacking ensemble method with two levels. This model consists of three different classifiers in the first level, followed by either a Naive Bayes or Decision Tree classifier for the second level. The model maintains an F1-score above 0.97 for malicious samples across all tested level two classifiers. Notably, Naive Bayes is the fastest level two classifier averaging 1.12 seconds while Decision Tree maintains the highest AUC score of 0.98
Technology and Policy: System Acquisition in a Complex Operational Environment
No full textThe United States’ (US) ability to maintain a technological edge in the current operational environment is challenged by the increased ability of near-peer nations to produce military technology. In response to this problem, the US Army Engineer Research and Development Center (ERDC) seeks to model the three key elements of military system acquisition—context, product, and process—to develop a more comprehensive understanding regarding how and why nations acquire technical solutions. Through the application of the System Dynamics Modeling Process (SDMP), this research examines the interactions between the strategic context of Germany, the military products it acquires to address its operational needs, and the processes it employs to acquire military technology. The results of this research indicate that numerous dynamic variables of context impact the acquisitions process for Germany, particularly political support and subsequent monetary allocations to research and development
Light-Weight Solution for High Speed Obstacle Avoidance
No full textThis paper proposes and evaluates a method of autonomous high-speed maneuvering, while simultaneously implementing an obstacle avoidance technique, in an unknown environment. Maneuvering in this context applies to controlling the Ackermann steering angle and speed of a small Unmanned Ground Vehicle (sUGV). The underlying principle applied in this research is a modified version of the ‘Open Path’ algorithm proposed by Wahlde et al., which processes LiDAR point clouds to make steering decisions. The original ’Open Path’ Algorithm was designed for a differential drive robot while the version proposed in this paper modifes that algorithm to fit an Ackermann steering vehicle
Progress Towards Educating the Engineer of 2020
Get PDFThe Engineer of 2020 was published in 2004 and predicted the roles that engineers would play in the year 2020. A companion text titled Educating the Engineer of 2020: Adapting Engineering Education to the New Century was published in 2005 and focused on changes necessary in engineering education to prepare engineers to practice in the year 2020. Both documents were heralded as inspirational, aspirational, and paradigm changing. But did change actually occur in the civil engineering curriculum?
The Engineer of 2020 report culminated in the presentation and description of a series of attributes. It is these attributes that the report suggested will “support the success and relevance of the engineering profession in 2020 and beyond.” The report acknowledges that those future attributes are similar to what made an engineer successful at the time the report was published, but technology was expected to make those attributes more complex.
This study investigates how civil engineering programs in the United States have adapted their curriculum to align with the attributes suggested in the report during the time period of 2005 - 2020. This study used a survey of civil engineering program leadership to collect their assessment of the importance of each of the attributes and to collect information related to program changes.
This study will be of interest to all civil engineering educators with an interest in ensuring that their graduates are prepared to meet The Engineer of 2020 attributes. This study will also be of interest to educators considering how the attributes described in 2004 remain relevant in 2020 and may spark conversation about how these attributes may need to be adjusted in the future. The study will be of particular interest to those responsible for recommending and implementing curricular changes in engineering programs
Shock to the System: How a Teaching and Learning Model Held up in a Global Pandemic
Get PDFIn the late 1990s, the Department of Civil and Mechanical Engineering at the U.S. Military Academy (West Point) formulated a teaching model which guided the training of new faculty. The model served faculty well as they provided instruction and developed learning activities. The model remained unchanged for about 15 years until a team of faculty conducted a methodical review of the literature, reflected on desired outcomes, and deliberated about the role that this model played in achieving the institution and department’s mission and vision. The result was an updated teaching and learning model which was presented at the ASEE National Convention in 2017. As was emphasized in a previous paper, the faculty believed strongly that the teaching and learning model be viewed as a living document that must be applied and regularly challenged, discussed, and updated to ensure it remained relevant.
When the coronavirus pandemic began in early 2020, the institution, which had very limited experience providing online instruction, sent students home, and switched to delivering fully remote courses within less than one week. Like most other academic institutions, this was a significant shock to the teaching and learning environment; faculty rapidly learned new tools and tried new techniques to teach, engage, and interact with students. After the semester ended, the department formed teams of faculty to devote a portion of the summer to gathering lessons learned from the spring term, examining the literature about online education, and providing recommendations for the fall term. These activities led to discussions about how well the existing teaching and learning model applied to the vastly different environment of online versus in-person education. This inspired the faculty to a thorough examination of the living document.
During the subsequent fall term, formal faculty discussions about the model were facilitated. Topics from these discussions were grouped as follows: (1) aspects of the model that can be applied unchanged in the online environment, (2) aspects of the model that are difficult or impossible to apply in the online environment, and (3) ideas that need to be included in the model to support the online environment. The discussions included topics unrelated to the online environment, highlighting important aspects of the model that deserve additional consideration. Results from these faculty discussions will inform a team of faculty that will develop an updated version of the model in the summer of 2021.
This work in progress paper summarizes the results from the discussions, highlights preliminary conclusions, and describes future work. This will be of interest to any engineering educator interested in developing and using a teaching and learning model as a guidepost for themselves or their department. This will also be of interest to educators desiring a better understanding of the similarities and differences between in-person and remote teachin