Oral exams provide a compelling alternative to traditional evaluation methods, expanding or replacing traditional written work. Interest in oral exams is growing rapidly in computer science (CS) education due to shifts to remote learning and concerns around AI-supported programming. This Birds of a Feather (BoF) session is broadly applicable to many in the CS education community, whether they have previously tried oral exams, have concerns about the use of oral exams in CS education, or are curious to hear more about how oral exams might work. The BoF session will provide a forum to discover and discuss previous approaches to oral exams, dive into common themes of interest in small groups, and collectively identify promising future directions for oral exams in CS courses.

An oral exam is an assessment approach involving verbal explanations of key concepts or thought process to achieve a solution to a problem, sometimes accompanied by written or typed work. As a complement or refreshing alternative to standard written assessments, oral exams are being implemented in CS courses in a variety of formats. This Birds of a Feather (BoF) session will bring together the growing community of CS educators who have previously used oral exams and those interested in alternative assessment approaches to share ideas and discuss best practices. The discussion leaders represent a wide range of institutions and have varied previous expertise in the design, implementation, and study of oral exams in CS courses. The BoF session will involve (1) introduction to oral exams and previous approaches led by the discussion leaders, (2) small group discussions based on shared interests or concerns with oral exams, and (3) discussion of best practices for oral exams in CS courses.

Oral proficiency exams implemented in introductory programming courses at a public, research, minority-serving university provide a way to connect with students one-on-one, keep students accountable on the course material to improve their learning, and help improve feelings of belongingness in the learning environment. This study analyzes data disaggregated based on majority and underrepresented demographic groups by gender, race/ethnicity, and parental education level, to investigate the following three research themes across all groups: (1) to determine the impact of the oral exams on student motivation for independent learning; (2) to compare student stress levels related to the oral exams; and (3) to compare belongingness and final course performance. Student survey data was collected and analyzed following the oral exam intervention. For research theme (1), students across nearly all demographic groups reported that oral exams improved their understanding of the material and encouraged them to do more independent work. For research theme (2), students in some underrepresented groups reported higher stress levels than their majority group peers, and all groups reported a reduction in stress level after completing the oral exam. For research theme (3), students in some underrepresented groups reported lower sense of belonging and had lower final course performance than their majority group peers.

Overflows in the ocean occur when dense water flows down a continental slope into less dense ambient water.It is important to study idealized and small-scale models, which allow for confidence and control of parameters.The work presented here is a direct qualitative and quantitative comparison between physical laboratory experiments and lab-scale numerical simulations.Physical parameters are varied, including the Coriolis parameter, the inflow density, and the inflow volumetric flow rate.Laboratory experiments are conducted using a rotating square tank and high-resolution camera mounted on the table in the rotating reference frame.Video results are digitized in order to compare directly to numerical simulations.The MIT General Circulation Model (MITgcm), a three-dimensional ocean model, is used for the direct numerical simulations corresponding to the specific laboratory experiments.It was found that the MITgcm was not a good match to laboratory experiments when physical parameters fell within the high eddy activity regime.However, a more extensive resolution study is needed to understand this fully.The MITgcm simulations did provide a good qualitative and quantitative match to laboratory experiments run in a low eddy activity regime.In all cases, the MITgcm simulations had more eddy activity than the laboratory experiments.

The effects of isothermal stratification strength on vorticity dynamics for single-mode Rayleigh-Taylor instability (RTI) are examined using two dimensional fully compressible wavelet-based direct numerical simulations. The simulations model low Atwood number ($A=0.04$) RTI development for four different stratification strengths, corresponding to Mach numbers from 0.3 (weakly stratified) to 1.2 (strongly stratified), and for three different perturbation Reynolds numbers, from 5,000 to 20,000. All simulations use adaptive wavelet-based mesh refinement to achieve very fine spatial resolutions at relatively low computational cost. For all stratifications, the bubble and spike go through the exponential growth regime, followed by a slowing of the RTI evolution. For the weakest stratification, this slow-down is then followed by a re-acceleration, while for stronger stratifications the suppression of RTI growth continues. Bubble and spike asymmetries are observed for weak stratifications, with bubble and spike growth rates becoming increasingly similar as the stratification strength increases. For the range of cases studied, there is relatively little effect of Reynolds number on bubble and spike heights, although the formation of secondary vortices becomes more pronounced as Reynolds number increases. The underlying dynamics are analyzed in detail through an examination of the vorticity transport equation, revealing that incompressible baroclinicity drives RTI growth for small and moderate stratifications, but increasingly leads to the suppression of vorticity production and RTI growth for stronger stratifications. These variations in baroclinicity are used to explain the suppression of RTI growth for strong stratifications, as well as the anomalous asymmetry in bubble and spike growth rates for weak stratifications.

The simulations compare, for the first time, three practically important background stratifications under thermal equilibrium and out of equilibrium (isentropic, isopycnic) and show significant differences on the instability growth

An investigation of compressible Rayleigh–Taylor instability (RTI) using Direct Numerical Simulations (DNS) requires efficient numerical methods, advanced boundary conditions, and consistent initialization in order to capture the wide range of scales and vortex dynamics present in the system, while reducing the computational impact associated with acoustic wave generation and the subsequent interaction with the flow. An advanced computational framework is presented that handles the challenges introduced by considering the compressive nature of RTI systems, which include sharp interfacial density gradients on strongly stratified background states, acoustic wave generation and removal at computational boundaries, and stratification dependent vorticity production. The foundation of the numerical methodology described here is the wavelet-based grid adaptivity of the Parallel Adaptive Wavelet Collocation Method (PAWCM) that maintains symmetry in single-mode RTI systems to extreme late-times. PAWCM is combined with a consistent initialization, which reduces the generation of acoustic disturbances, and effective boundary treatments, which prevent acoustic reflections. A dynamic time integration scheme that can handle highly nonlinear and potentially stiff systems, such as compressible RTI, completes the computational framework. The numerical methodology is used to simulate two-dimensional single-mode RTI to extreme late-times for a wide range of flow compressibility and variable density effects. The results show that flow compressibility acts to reduce the growth of RTI for low Atwood numbers, as predicted from linear stability analysis.

MPAS-Ocean is used to simulate an idealized, density-driven overflow using the dynamics of overflow mixing and entrainment (DOME) setup. Numerical simulations are carried out using three of the vertical coordinate types available in MPAS-Ocean, including z-star with partial bottom cells, z-star with full cells, and sigma coordinates. The results are first benchmarked against other models, including the MITgcm's z-coordinate model and HIM's isopycnal coordinate model, which are used to set the base case used for this work. A full parameter study is presented that looks at how sensitive overflow simulations are to vertical grid type, resolution, and viscosity. Horizontal resolutions with 50 km grid cells are under-resolved and produce poor results, regardless of other parameter settings. Vertical grids ranging in thickness from 15 m to 120 m were tested. A horizontal resolution of 10 km and a vertical resolution of 60 m are sufficient to resolve the mesoscale dynamics of the DOME configuration, which mimics real-world overflow parameters. Mixing and final buoyancy are least sensitive to horizontal viscosity, but strongly sensitive to vertical viscosity. This suggests that vertical viscosity could be adjusted in overflow water formation regions to influence mixing and product water characteristics. Lastly, the study shows that sigma coordinates produce much less mixing than z-type coordinates, resulting in heavier plumes that go further down slope. Sigma coordinates are less sensitive to changes in resolution but as sensitive to vertical viscosity compared to z-coordinates. (C) 2015 Elsevier Ltd. All rights reserved.

Programming is a crucial skill for today's engineering student. The majority of mechanical engineering programs in the US include an "introduction to programming" course taken during the first or second year. The primary goal of the course is to providing students with the basic programming techniques that are required to excel in specific mechanical engineering fields of study. Additionally, the course aims to develop a variety of skills that transcend all scientific disciplines, including problem solving, logical reasoning, debugging, and software training. A course in programming can be challenging for many students choosing to major in mechanical engineering. The major attracts students with diverse backgrounds and a wide variety of academic interests. It is uncommon for students to choose to study mechanical engineering because of their interest in programming or modeling. This often leads to a disconnect between the students and the instructor, which can create an intimidating classroom environment. The work presented here is driven by these findings.A new programming course has been developed to address the problems existing in the original course model, which include: (a) the course being offered outside of an engineering department, (b) the extreme variability in the rate at which the students comprehend the material, and (c) the frustration of new programmers, especially with debugging. Backward course design(1) was used to redesign the course, addressing all of the existing problems. First, the new course focuses on engineering specific computational applications, is taught by a Mechanical Engineering professor, and uses a more practical programming language, MATLAB. Thus, the essentials of programming are introduced within a focused framework that cultivates the development of analytical tools commonly used in engineering disciplines, such as statistics, data analysis, numerical differentiation and integration, and Fourier analysis. Second, the Process-Oriented Guided Inquiry Learning (POGIL) method(2) is used so that students are self-guided through part of the instruction. Lastly, class time is organized in such a way that the instructor spends over half of the time working directly with individuals and small groups. This gives the students an opportunity to have explanations individually catered to their level of understanding, as well as plenty of time for peer and instructor assistance with debugging.The course initially ran under the new model in Spring, 2013. The course ran for 15 weeks and had 37 students split into two different sections. There were no teaching assistants. Feedback from the students indicated that they benefitted greatly from the course design. Improvements for the second iteration of the new course model, which will occur in Spring, 2014, include lengthening the course from 2.5 hours per week to 4 hours per week, utilizing more traditional lecture, incorporating class discussions, adding student created supplementary video content in the essence of classroom flipping(3), and integrating an overarching humanitarian theme to all assignments in an effort to support the liberal arts goals of the university.

Numerical simulations of the compressible Rayleigh-Taylor instability are performed on an adaptive mesh using the Adaptive Wavelet Collocation Method (AWCM). Due to the physicsbased adaptivity and direct error control of the method, AWCM is ideal for resolving the wide range of scales present in the development of the instability. The problem is initialized consistent with the solutions from linear stability theory, with a background state of two diffusively mixed, stratified fluids of differing molar masses. Of interest are the compressibility effects on the departure time from the linear growth, the onset of strong non-linear interactions, and the late-time behavior of the fluid structures. The late time bubble and spike velocities are computed and compared to those obtained in the incompressible case.