Analysis of Traveler Characteristics by Mode Choice in HOT Corridors

This research examined travelers who have a vast array of travel options, including some rather unique ones: HOV3+ in an HOV lane, HOV2+ in an HOV lane off-peak, HOV2 plus a $2.00 toll in an HOV lane during the peak, and casual carpooling (slugging). Travelers using all these modes were surveyed in 2003, and significant differences between the groups of travelers were observed, providing some understanding of travel behavior when faced with these travel options. In the study, particular effort was spent on examining the characteristics of travelers who choose to travel as HOV2 carpools during peak periods and pay a$2.00 toll. This group of travelers was found to contain significantly more well-educated females with high household incomes on school related trips. The proximity of private schools near the terminus of the HOV lane probably contributed significantly to this result. Due to the array of mode choices available to these travelers, surveying all these groups was challenging and, therefore, the methodology employed in survey development and administration is also detailed in this paper

Adulting 101: Know Your Audience

During the winter of 2017, I began to see a common topic on library programming group threads centering around ideas such as teaching basic life skills to young and new adults that may not have been taught at home or school. Around the same time, Clara Piazzola, the library’s young adult assistant, came to me to share an idea that was buzzing around her library school discussion boards. She told me about a program idea that would teach young people necessary skills to help them survive in the grownup world. Talk about a coincidence! I gave her the go ahead, and she began planning. Clara came up with the name, Adulting 101, and a six-month program outline. Planning each session, we chose to invite local speakers for a few of the topics that warranted professional facilitators. Flyers were displayed in the library and mailed to local bulletin boards and radio stations. Adulting 101 was posted to the library website, social media, and electronic calendars. We reserved the room, bought snacks, and were ready to launch. The event post on our library’s Facebook page started a ripple effect that took us by surprise. We had Facebook likes and shares from tens of thousands of viewers. People were emailing and phoning our City Administrator, Library Director, and the library for more information. The local television station saw the post, called for an interview, and covered the first program. There were radio interviews. We had electronic inquiries and phone calls from across the country and then some. The American Library Association’s Programming Librarian asked for an article (Lucas, 2017). Adulting 101 was even mentioned on the morning talk show LiveKellyandRyan (Adulting 101 for Millenials [sic], 2017)

Integrated System Health Management (ISHM) and Autonomy

Systems capabilities on ISHM (Integrated System Health Management) and autonomy have traditionally been addressed separately. This means that ISHM functions, such as anomaly detection, diagnostics, prognostics, and comprehensive system awareness have not been considered traditionally in the context of autonomy functions such as planning, scheduling, and mission execution. One key reason is that although they address systems capabilities, both ISHM and autonomy have traditionally individually been approached as independent strategies and models for analysis. Additionally, to some degree, a unified paradigm for ISHM and autonomy has been difficult to implement due to limitations of hardware and software. This paper explores a unified treatment of ISHM and autonomy in the context of distributed hierarchical autonomous operations

Using Decision Trees to Detect and Isolate Simulated Leaks in the J-2X Rocket Engine

The goal of this work was to use data-driven methods to automatically detect and isolate faults in the J-2X rocket engine. It was decided to use decision trees, since they tend to be easier to interpret than other data-driven methods. The decision tree algorithm automatically "learns" a decision tree by performing a search through the space of possible decision trees to find one that fits the training data. The particular decision tree algorithm used is known as C4.5. Simulated J-2X data from a high-fidelity simulator developed at Pratt & Whitney Rocketdyne and known as the Detailed Real-Time Model (DRTM) was used to "train" and test the decision tree. Fifty-six DRTM simulations were performed for this purpose, with different leak sizes, different leak locations, and different times of leak onset. To make the simulations as realistic as possible, they included simulated sensor noise, and included a gradual degradation in both fuel and oxidizer turbine efficiency. A decision tree was trained using 11 of these simulations, and tested using the remaining 45 simulations. In the training phase, the C4.5 algorithm was provided with labeled examples of data from nominal operation and data including leaks in each leak location. From the data, it "learned" a decision tree that can classify unseen data as having no leak or having a leak in one of the five leak locations. In the test phase, the decision tree produced very low false alarm rates and low missed detection rates on the unseen data. It had very good fault isolation rates for three of the five simulated leak locations, but it tended to confuse the remaining two locations, perhaps because a large leak at one of these two locations can look very similar to a small leak at the other location

Irreducible background of gravitational waves from a cosmic defect network : Update and comparison of numerical techniques

Cosmological phase transitions in the early Universe may produce relics in the form of a network of cosmic defects. Independently of the order of a phase transition, topology of the defects, and their global or gauge nature, the defects are expected to emit gravitational waves (GWs) as the network energy-momentum tensor adapts itself to maintaining scaling. We show that the evolution of any defect network (and for that matter any scaling source) emits a GW background with spectrum Omega(GW) proportional to f(3) for f > f(eq), where f(0) and f(eq) denote respectively the frequencies corresponding to the present and matter-radiation equality horizons. This background represents an irreducible emission of GWs from any scaling network of cosmic defects, with its amplitude characterized only by the symmetry-breaking scale and the nature of the defects. Using classical lattice simulations we calculate the GW signal emitted by defects created after the breaking of a global symmetry O(N) -> O(N - 1). We obtain the GW spectrum for N between 2 and 20 with two different techniques: integrating over unequal-time correlators of the energy-momentum tensor, updating our previous work on smaller lattices, and for the first time, comparing the result with the real-time evolution of the tensor perturbations sourced by the same defects. Our results validate the equivalence of the two techniques. Using cosmic microwave background upper bounds on the defects' energy scale, we discuss the difficulty of detecting this GW background in the case of global defects.Peer reviewe

NASA Platform for Autonomous Systems (NPAS)

NASA Platform for Autonomous Systems (NPAS) is a disruptive software platform and processes being developed by the NASA Stennis Space Center (SSC) Autonomous Systems Laboratory (ASL). Autonomous operations are critical for the success, safety and crew survival of NASA deep space missions beyond low Earth orbit, including the Gateway, and for the future of cost-effective ground mission operations. NPAS represents the embodiment of an innovative paradigm for thinking autonomy in contrast to brute-force autonomy. NPAS uniquely addresses the requirements and integrates the primary functionalities for autonomous operations, in one platform that includes: (1) Integrated System Health Management (ISHM); (2) autonomy strategies, guided by system health and concepts of operations; (3) domain objects (system elements) and infrastructure to create complete application domain knowledge models (4) infrastructure to create, schedule, and execute mission plans; (5) infrastructure to develop user interfaces for comprehensive awareness; and (6) infrastructure to integrate distributed autonomous applications across networks. NPAS is a single platform that can be used to make any system operate with any desirable degree of autonomy, as well as provide comprehensive system awareness to operators and users

Integrated System Health Management (ISHM) Implementation in Rocket Engine Testing

A pilot operational ISHM capability has been implemented for the E-2 Rocket Engine Test Stand (RETS) and a Chemical Steam Generator (CSG) test article at NASA Stennis Space Center. The implementation currently includes an ISHM computer and a large display in the control room. The paper will address the overall approach, tools, and requirements. It will also address the infrastructure and architecture. Specific anomaly detection algorithms will be discussed regarding leak detection and diagnostics, valve validation, and sensor validation. It will also describe development and use of a Health Assessment Database System (HADS) as a repository for measurements, health, configuration, and knowledge related to a system with ISHM capability. It will conclude with a discussion of user interfaces, and a description of the operation of the ISHM system prior, during, and after testing