skip to main content

Search for: All records

Creators/Authors contains: "Nguyen, H."

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Free, publicly-accessible full text available August 1, 2023
  2. Free, publicly-accessible full text available August 1, 2023
  3. Free, publicly-accessible full text available April 15, 2023
  4. Free, publicly-accessible full text available January 1, 2023
  5. Free, publicly-accessible full text available November 19, 2022
  6. Abstract: Developing student interest is critical to supporting student learning in computer science. Research indicates that student interest is a key predictor of persistence and achievement. While there is a growing body of work on developing computing identities for diverse students, little research focuses on early exposure to develop multilingual students’ interest in computing. These students represent one of the fastest growing populations in the US, yet they are dramatically underrepresented in computer science education. This study examines identity development of upper elementary multilingual students as they engage in a year-long computational thinking curriculum, and follows their engagement across multiple settings (i.e., school, club, home, community). Findings from pre- and -post surveys of identity showed significant differences favoring students’ experiences with computer science, their perceptions of computer science, their perceptions of themselves as computer scientists, and their family support for computer science. Findings from follow-up interviews and prior research suggest that tailored instruction provides opportunities for connections to out-of-school learning environments with friends and family that may shift students’ perceptions of their abilities to pursue computer science and persist when encountering challenges.
    Free, publicly-accessible full text available November 1, 2022
  7. This work presents the design and autonomous navigation policy of the Resilient Micro Flyer, a new type of collision-tolerant robot tailored to fly through extremely confined environments and manhole-sized tubes. The robot maintains a low weight (<500g) and implements a combined rigid-compliant design through the integration of elastic flaps around its stiff collision-tolerant frame. These passive flaps ensure compliant collisions, contact sensing and smooth navigation in contact with the environment. Focusing on resilient autonomy, capable of running on resource-constrained hardware, we demonstrate the beneficial role of compliant collisions for the reliability of the onboard visual-inertial odometry and propose a safe navigation policy that exploits both collision-avoidance using lightweight time-of-flight sensing and adaptive control in response to collisions. The robot further realizes an explicit manhole navigation mode that exploits the direct mechanical feedback provided by the flaps and a special navigation strategy to self-align inside manholes with non-straight geometry. Comprehensive experimental studies are presented to evaluate, both individually and as a whole, how resilience is achieved based on the robot design and its navigation scheme.
  8. Rates of development of the feeding larvae of marine invertebrates may often be limited by inadequate food, extending the length of the larval period and increasing overall larval mortality. A better understanding of the frequency and importance of this phenomenon requires knowledge of the food concentration below which larvae are limited, and above which they are not, as well as estimates of how strongly food supply affects length of the planktonic period. We addressed these issues using larvae of the sand dollar Dendraster excentricus as a model and chl a concentration as a metric of food abundance. We reared larvae in natural seawater collected from coastal southern California (USA), as well as in reduced and supplemented food treatments created from this natural seawater, 6 times from 2017 to 2019 to take advantage of temporal variation in chl a concentration. Larvae showed morphological responses indicative of low food in nature in only 1 of 6 experiments and showed delayed time to 50% metamorphic competence in 2 of 6 experiments. Larvae appeared to be food limited below chl a concentrations of ~2.4-3.0 µg l -1 , but developed at maximal rates at higher food concentrations. Low natural food supplies delayed time tomore »50% competence by up to 1.25 d. An 11 yr record of chl a concentration in waters of coastal southern California suggests that larvae of D. excentricus are likely food limited in developmental rate throughout much of the year except for late winter to late spring.« less