Jinghui Cheng

Fast Identification of Inactive Security Constraints in SCUC Problems

Security constrained unit commitment (SCUC) is one of the most important daily tasks that independent system operators (ISOs) or regional transmission organizations (RTOs) must accomplish in daily electric power market. Security constraints have long been regarded as difficult constraints for unit commitment problems. If the inactive security constraints can be identified and eliminated, the SCUC problem can be greatly simplified. In this paper, a necessary and sufficient condition for a security constraint to be inactive is established. It is proved that all inactive constraints can be identified by solving a series of small-scale mixed integer linear programming (MILP) problems. More importantly, an analytical sufficient condition is established and most of the inactive constraints can be quickly identified without solving MILP or linear programming (LP) problems. A very important feature of the conditions obtained is that they are only related to the load demands and parameters of the transmission network. Numerical testing is performed for three power grids and the results are impressive. Over 85% of the security constraints are identified as inactive and the crucial transmission lines affecting the total operating cost are among those associated with the remaining security constraints, providing useful information for transmission planning.

Best Practices for Teaching Accessibility in University Classrooms: Cultivating Awareness, Understanding, and Appreciation for Diverse Users

As Information and Communication Technologies (ICTs) become more diffuse, developers and designers need to consider a growing diversity of users including people with disabilities and aging populations. As a result, computing education needs to respond by providing students opportunities to learn about accessibility and designing for inclusion. This article presents results of a qualitative research study of practices in teaching accessibility in university-level programs in the US. The study included interviews with 18 professors from some of the top universities in the US and a content analysis of syllabi and other teaching materials. Using the pedagogical theory of authentic learning and elements from the 21st Century Skills framework, we found that instructors emphasized the need for students to develop awareness and understanding for a diversity of ICT users through multiple different experiences; experiences that included research projects that directly involve users with disabilities, guest speakers, field trips, simulating disabilities, and the use of videos/movies. Additionally, instructors used multiple resources (e.g., research papers, online resources), in part, to offset the challenge that there is a perceived lack of a comprehensive textbook. Instructors also emphasized the importance of their individual initiative; that is, the inclusion of accessible topics or courses was often linked to a faculty members research and/or personal commitment. This article contributes to a gap in the literature by disseminating and sharing different approaches to teaching accessibility across multiple instructors, courses, and campuses.

How do professionals who create computing technologies consider accessibility

In this paper, we present survey findings about how user experience (UX) and human-computer interaction (HCI) professionals, who create information and communication technologies (ICTs), reported considering accessibility in their work. Participants (N = 199) represented a wide range of job titles and nationalities. We found that most respondents (87%, N = 173) reported that accessibility was important or very important in their work; however, when considerations for accessibility were discussed in an open-ended question (N =185) the scope was limited. Additionally, we found that aspects of empathy and professional experience were associated with how accessibility considerations were reported. We also found that many respondents indicated that decisions about accessibility were not in their control. We argue that a better understanding about how accessibility is considered by professionals has implications for academic programs in HCI and UX as to how well programs are preparing students to consider and advocate for inclusive design.

Semantically enhanced software traceability using deep learning techniques

In most safety-critical domains the need for traceability is prescribed by certifying bodies. Trace links are generally created among requirements, design, source code, test cases and other artifacts, however, creating such links manually is time consuming and error prone. Automated solutions use information retrieval and machine learning techniques to generate trace links, however, current techniques fail to understand semantics of the software artifacts or to integrate domain knowledge into the tracing process and therefore tend to deliver imprecise and inaccurate results. In this paper, we present a solution that uses deep learning to incorporate requirements artifact semantics and domain knowledge into the tracing solution. We propose a tracing network architecture that utilizes Word Embedding and Recurrent Neural Network (RNN) models to generate trace links. Word embedding learns word vectors that represent knowledge of the domain corpus and RNN uses these word vectors to learn the sentence semantics of requirements artifacts. We trained 360 different configurations of the tracing network using existing trace links in the Positive Train Control domain and identified the Bidirectional Gated Recurrent Unit (BI-GRU) as the best model for the tracing task. BI-GRU significantly out-performed state-of-the-art tracing methods including the Vector Space Model and Latent Semantic Indexing.

Therapeutic Gaming in Context: Observing Game Use for Brain Injury Rehabilitation

Video games are often used in brain injury (BI) therapy sessions to help motivate patients to engage in rehabilitation activities. However, very little is known about contexts of game use in real-world rehabilitation settings. In this paper, we explore contexts of commercial game use in BI therapy through observation of inpatient therapy sessions. Based on a systematic analysis of the observation recordings, we found that (1) only 30% of session time was used for gameplay; (2) therapists needed to provide various kinds of cognitive and physical patient support during the play sessions; and (3) therapists adopted multiple strategies to reinforce the therapeutic values of the games. This study is helping us create decision and information sharing tools to support the use and creation of games for BI rehabilitation.

Therapist-centered requirements: A multi-method approach of requirement gathering to support rehabilitation gaming

Brain injuries (BI) are recognized as a major public health issue. Many therapists include commercial motion-based videogames in their therapy sessions to help make rehabilitation exercises fun and engaging. Our initial exploratory work exposed a need for tools to help therapists make evidence-based decisions when choosing commercial motion-games for their patients who have had a BI. Targeting this need, we are gathering requirements for a case-based recommender (CBR) system that will act as a decision tool for therapists. In this paper, we describe our ongoing work as a case study that illustrates our multi-method approach of requirement elicitation for the CBR system. Our approach is comprised of four overlapping steps: (1) interviews with therapists, (2) onsite observations of therapy game sessions, (3) diary studies in which therapists record detailed information about game sessions, and (4) a user study of a CBR prototype interface. Leveraging direct interaction with end users (i.e., therapists), this case study demonstrates requirements gathering techniques to address needs of a special population (i.e., therapists who work with patients who had BIs) in a specialized context (i.e., inpatient rehabilitation using motion-based video games).

Supporting therapists in motion-based gaming for brain injury rehabilitation

In this paper, we describe a work-in-progress that involves therapists who use commercial motion-based video games (e.g. Wii) in therapies involving patients who have had a brain injury (BI). We are collecting data to inform a case-based recommender (CBR) system that will help therapists stay current and choose appropriate motion-games for their patients. Data from the CBR system will (1) establish commercial motion-game efficacy among a larger and more diverse BI patient population than in previous work and (2) inform custom games that better meet needs for BI therapies.

Human-Centered Design in Practice: Roles, Definitions, and Communication

Human-centered design philosophy proposes that end users be at the center of technical system designs. Building on a seminal study by Gould and Lewis, we present findings from two surveys that explored the practice of building interactive systems from the perspective of information and communication technology (ICT) professionals. We generated ICT job descriptions based on a lexicon derived from practitioners’ own words. We found that while “human-centeredness” has risen among ICT professionals, our respondents varied significantly in how they considered the original three Gould and Lewis principles with respect to their job titles and roles. We thus argue that tools that support clear communication among roles are critical; in this project, we analyzed personas as a common ICT communication tool. While personas were generally perceived positively, persona creators need to consider factors that contribute to buy-in from design teams, including quality research and effective presentation.

Teaching Accessibility, Learning Empathy

As information and communication technologies (ICTs) become more diffuse, the diversity of users that designers need to consider is growing; this includes people with disabilities and aging populations. As a result, computing education must provide students the means and inspiration to learn about inclusive design. This poster presents top-level findings from 18 interviews with professors from some of the top universities in the US. Our analysis yielded four categories of findings: (1) important student learning outcomes (the most common was for students to embrace diversity); (2) exercises and teaching materials (almost all focused on inclusion of people with disabilities in discovery and evaluation of ICTs); (3) frustrations and challenges (largely focused on how to engage students in accessibility topics); and (4) the importance of instructor initiative to include the topic of accessibility in their teaching. The unifying theme was the high importance of cultivating empathy with end users.

How Do the Open Source Communities Address Usability and UX Issues?: An Exploratory Study

Usability and user experience (UX) issues are often not well emphasized and addressed in open source software (OSS) development. There is an imperative need for supporting OSS communities to collaboratively identify, understand, and fix UX design issues in a distributed environment. In this paper, we provide an initial step towards this effort and report on an exploratory study that investigated how the OSS communities currently reported, discussed, negotiated, and eventually addressed usability and UX issues. We conducted in-depth qualitative analysis of selected issue tracking threads from three OSS projects hosted on GitHub. Our findings indicated that discussions about usability and UX issues in OSS communities were largely influenced by the personal opinions and experiences of the participants. Moreover, the characteristics of the community may have greatly affected the focus of such discussion.