On Data Analysis Pipelines and Modular Bayesian Modeling

The most common approach to implementing data analysis pipelines involves obtaining point estimates from the upstream modules and then treating these as known quantities when working with the downstream ones. This approach is straightforward, but it is likely to underestimate the overall uncertainty associated with any final estimates. An alternative approach involves estimating parameters from the modules jointly using a Bayesian hierarchical model, which has the advantage of propagating upstream uncertainty into the downstream estimates. However, when modules are misspecified, such a joint model can behave in unexpected ways. Furthermore, hierarchical models require the development of ad-hoc computational implementations that can be laborious and computationally expensive. Cut inference modifies the posterior distribution to prevent information flow between certain parameters and provides a third alternative for statistical inference in data analysis pipelines. This paper presents a unified framework that encompasses two-step, cut, and joint inference in the context of data analysis pipelines with two modules and uses two examples to illustrate the tradeoffs associated with these approaches. Our work shows that cut inference provides both some level of robustness and ease of implementation for data analysis pipelines at a lower cost in terms of statistical inference

Explaining Differences in Voting Patterns Across Voting Domains Using Hierarchical Bayesian Models

Spatial voting models of legislators' preferences are used in political science to test theories about their voting behavior. These models posit that legislators' ideologies as well as the ideologies reflected in votes for and against a bill or measure exist as points in some low dimensional space, and that legislators vote for positions that are close to their own ideologies. Bayesian spatial voting models have been developed to test sharp hypotheses about whether a legislator's revealed ideal point differs for two distinct sets of bills. This project extends such a model to identify covariates that explain whether legislators exhibit such differences in ideal points. We use our method to examine voting behavior on procedural versus final passage votes in the U.S. house of representatives for the 93rd through 113th congresses. The analysis provides evidence that legislators in the minority party as well as legislators with a moderate constituency are more likely to have different ideal points for procedural versus final passage votes

The Legacy Lives On: An Examination of Handel’s Continued Influence

Composers can meet fame in their lives and after death, but no composer has garnered the extent of fame George Frideric Handel did after death. Handel reached an abundance of success in various cities before his death, and even more success in new cities and a new continent after he passed. His fame after death was kept alive through his audience’s efforts to celebrate, perform, and preserve his works millenniums after his death

Obsidian in Northern Ecuador: A Study of Obsidian Production and Site Function in Pambamarca

For several years the Pambamarca Archaeology Project has been investigating a dynamic frontier in the northern Ecuadorian highlands at the edge of the País Caranqui: a confederation of small-scale, autonomous, inter-warring pre-Inkan polities whose nearly twenty year resistance to Inka conquest resulted in the largest concentration of military fortresses in the Inka Empire. In addition to its violent past, Pambamarca is located within 25km of high quality obsidian sources, making it an important region for understanding obsidian production when it is part of local, non-elite exchange. This study analyzes obsidian, non-obsidian flaked lithics, and ceramics to elucidate patterns of obsidian production and site function at five of the Pambamarca sites ranging chronologically from the Early Integration period to the early Colonial Period. Directions for future research which would better clarify these patterns are also proposed

Generalized Near Horizon Extreme Binary Black Hole Geometry

We present a new vacuum solution of Einstein’s equations describing the near horizon region of two neutral, extreme (zero-temperature), corotating, nonidentical Kerr black holes. The metric is stationary, asymptotically near horizon extremal Kerr (NHEK), and contains a localized massless strut along the symmetry axis between the black holes. In the deep infrared, it flows to two separate throats which we call “pierced-NHEK” geometries: each throat is NHEK pierced by a conical singularity. We find that in spite of the presence of the strut for the pierced-NHEK geometries the isometry group SL(2,R)×U(1) is restored. We find the physical parameters and entropy

Documenting Engineering Identity: Electrical and Computer Engineering Departmental Documents and Student Identity

As concerns about the preparation of engineers grow, so has interest in the dimensions of engineering identity. By having a thorough understanding of engineering identity, departments will be better able to produce engineers who understand their role as a member of the profession. Generally, engineering identity literature has not focused on specific disciplinary identities, instead looking at engineering as a whole. Previous literature has utilized role identity theory (e.g., Gee, 2001) and identified key dimensions of engineering identity, including one’s performance/competence and interest in engineering courses and recognition as a current/future engineer (Godwin, 2016; Godwin et al., 2013; Godwin et al., 2016). This paper deepens our understanding of electrical and computer engineering identities. As part of research activities associated with National Science Foundation grant looking at professional formation of socio-technically minded students, we analyzed texts and documents from an electrical and computer engineering department to examine the department’s professed priorities. Using document analysis, we answered this research question: How is a department’s commitment to undergraduate engineering identity development expressed in departmental documents? Document analysis focuses on texts to describe some aspect of the social world (Bowen, 2009). This analysis was performed with two types of departmental documents: front-facing documents (e.g., websites, newsletters) and internal documents (e.g., ABET self-studies, program evaluations) from an electrical and computing engineering department at a public research university. Analysis employed a priori and emergent coding schemas to formulate themes related to identity, performance/capability, interest, and recognition present in departmental documents (Bowen, 2009; Godwin, 2016). Specifically, we skimmed documents to ascertain inclusion status; read and coded documents in depth; and identified broader themes across documents (Bowen, 2009). One broad theme was a lack of attention to identity; another showed emphasis on technical skills/competencies. By interrogating absences, we found that there is little attention being paid to identity development or its components in these documents. In other words, these texts do not indicate that the department is invested in supporting students’ senses of interest, performance, and recognition as electrical and computer engineers. Rather, we found that these texts emphasize the acquisition of specific concepts, skills, and competencies. Overall, analysis indicated that the department does not cultivate holistic engineering student identities. The resultant implications are by no means irrelevant—a focus on identity over specific skills could increase retention, increase student satisfaction, and produce better future engineers

Intersections of Design Thinking and Perceptions of Success for Electrical, Computer, and Software Engineering Students

Engineering design thinking has become an important part of the educational discussion for both researchers and practitioners. Colleges and universities seek to graduate engineering students who can engage in the complex nature of combining both technical performance with design thinking skills. Prior research has shown that design thinking can be a solution for solving complicated technical and social issues in a holistic, adaptive way. However, little is known about how students make sense of their design thinking experiences and reconcile that into their perceptions of what it means to be a successful engineer. As part of a five-year National Science Foundation REvolutionizing Engineering and Computer Science Departments (NSF-RED) grant, this study highlights the experiences of students engaged in a course which has been redesigned to enhance student development through design thinking pedagogy. This case study sought to understand how electrical, computer, and software engineering students engage with design thinking and how that engagement shapes their perceptions of what success looks like. The case study was informed through observations of lecture and lab classroom contexts, interviews with students, and a review of relevant course documents. Participants met the following criteria: (a) were over the age of 18, (b) majoring in CES engineering, and (c) were currently enrolled in one of two courses currently undergoing redesign: a second-year electrical engineering course called Circuits or a second-year computer engineering course called Embedded Systems. Preliminary findings reveal that students engaged in the design thinking course described a disconnect between design thinking elements of the course and their perceptions of what it meant to be a successful electrical, computer, or software engineer. Although design thinking concepts focused on empathy-building and customer needs, it was often difficult for engineering students to see beyond the technical content of their course and conceptualize elements of design thinking as essential to their successful performance as engineers. This study bears significance to practitioners and researchers interested in (re)designing curriculum to meet the growing needs of innovation for today’s customer’s. Implications for policy and practice will be discussed to enhance the way that engineering programs, curricula, and workforce training are created

Deporting Fathers: Involuntary Transnational Families and Intent to Remigrate among Salvadoran Deportees

One-fourth of deportees from the U.S. are parents of U.S.-citizen children. We do not know how separation from families affects remigration among deportees, who face high penalties given unlawful reentry. We examined how family separation affects intent to remigrate among Salvadoran deportees. The majority of deportees with children in the U.S. were also separated from their spouse, and the vast majority had U.S.-citizen children. Family separation was the single most important factor affecting intent to remigrate. We interpret these findings in light of immigration policy debates