A Train Protection Logic Based on Topological Manifolds for Virtual Coupling

Virtual coupling is a promising innovation aimed at increasing railway capacity. Compared to current railway signaling systems, it allows two or more trains to run with reduced headway between them. However, such reduced headways are a challenge to safety. In this work we consider this challenge by formally describing and verifying an approach to virtual coupling. We propose a general modeling method based on topological manifolds to describe the protection logic for virtual coupling train control systems. We also describe the basic train control elements in topological terms and analyze the line condition of our virtual coupling logic. We establish that the line condition safety requirements and its representation as a manifold are equivalent and further provide a formal definition of the concept of a movement authority with manifold notations. This allows us to consider the dynamic behavior of trains and a series of theorems that establish the correctness of our protection logic for virtual coupling. Finally, we apply the presented methods to a case study. The results show that the proposed method provides a suitable way to realize a virtual coupling logic safely

Advances in fault diagnosis for high-speed railway: A review

The high speed railway (HSR) is a complex system with many subsystems and components. The reliability of its core subsystems is a key consideration in ensuring the safety and operation efficiency of the whole system. As the service time increases, the degradation of these subsystems and components may lead to a range of faults and deteriorate the whole system performance. To ensure the operation safety and to develop reasonable maintenance strategies, fault detection and isolation is an indispensable functionality in high speed railway systems. In this paper, the traction power supply system, bogie system, civil infrastructure system, and control and signaling system of HSR are briefly summarized, and then different fault diagnosis methods for these subsystems are comprehensively reviewed. Finally, some future research topics are discussed

VERIFICATION AND APPLICATION OF DETECTABILITY BASED ON PETRI NETS

In many real-world systems, due to limitations of sensors or constraints of the environment, the system dynamics is usually not perfectly known. However, the state information of the system is usually crucial for the purpose of decision making. The state of the system needs to be determined in many applications. Due to its importance, the state estimation problem has received considerable attention in the discrete event system (DES) community. Recently, the state estimation problem has been studied systematically in the framework of detectability. The detectability properties characterize the possibility to determine the current and the subsequent states of a system after the observation of a finite number of events generated by the system. To model and analyze practical systems, powerful DES models are needed to describe the different observation behaviors of the system. Secondly, due to the state explosion problem, analysis methods that rely on exhaustively enumerating all possible states are not applicable for practical systems. It is necessary to develop more efficient and achievable verification methods for detectability. Furthermore, in this thesis, efficient detectability verification methods using Petri nets are investigated, then detectability is extended to a more general definition (C-detectability) that only requires that a given set of crucial states can be distinguished from other states. Formal definitions and efficient verification methods for C-detectability properties are proposed. Finally, C-detectability is applied to the railway signal system to verify the feasibility of this property: 1. Four types of detectability are extended from finite automata to labeled Petri nets. In particular, strong detectability, weak detectability, periodically strong detectability, and periodically weak detectability are formally defined in labeled Petri nets. 2. Based on the notion of basis reachability graph (BRG), a practically efficient approach (the BRG-observer method) to verify the four detectability properties in bounded labeled Petri nets is proposed. Using basis markings, there is no need to enumerate all the markings that are consistent with an observation. It has been shown by other researchers that the size of the BRG is usually much smaller than the size of the reachability graph (RG). Thus, the method improves the analysis efficiency and avoids the state space explosion problem. 3. Three novel approaches for the verification of the strong detectability and periodically strong detectability are proposed, which use three different structures whose construction has a polynomial complexity. Moreover, rather than computing all cycles of the structure at hand, which is NP-hard, it is shown that strong detectability can be verified looking at the strongly connected components whose computation also has a polynomial complexity. As a result, they have lower computational complexity than other methods in the literature. 4. Detectability could be too restrictive in real applications. Thus, detectability is extended to C-detectability that only requires that a given set of crucial states can be distinguished from other states. Four types of C-detectability are defined in the framework of labeled Petri nets. Moreover, efficient approaches are proposed to verify such properties in the case of bounded labeled Petri net systems based on the BRG. 5. Finally, a general modeling framework of railway systems is presented for the states estimation using labeled Petri nets. Then, C-detectability is applied to railway signal systems to verify its feasibility in the real-world system. Taking the RBC handover procedure in the Chinese train control system level 3 (CTCS-3) as an example, the RBC handover procedure is modeled using labeled Petri nets. Then based on the proposed approaches, it is shown that that the RBC handover procedure satisfies strongly C-detectability

Business optimization through automated signaling design

M.Ing. (Engineering Management)Abstract: Railway signaling has become pivotal in the development of railway systems over the years. There is a global demand for upgrading signaling systems for improved efficiency. Upgrading signaling systems requires new signaling designs and modifications to adjacent signaling systems. The purpose of this research is to compare manually produced designs with design automation by covering the framework of multiple aspects of railway signaling designs in view of business optimization using computer drawings, programming software language and management of signaling designs. The research focuses on design automation from the preliminary design stage to the detailed design stage with the intention of investigating and resolving a common project challenge of time management. Various autonomous methods are used to seek improvement on the detailed design phase of re-signaling projects. An analysis on the project’s duration, resources and review cycles is conducted to demonstrate the challenges that are faced during the design of a project. Signaling designs are sophisticated and crucial in an ever-changing railway environment. As a result, there is a demand for efficiency and knowledge within railway signaling to achieve successful completion project target dates. A quantitative approach is used to identify the gaps leading to delays and best practices are applied using a comparative analysis to remediate on any snags that may potentially extend the project duration. The results illustrate that the resources required when automating detailed designs are reduced by two thirds for cable plans and book of circuits and reduced by one third for source documents. Successively, the projects benefit with reduced organizational resources, reduced design durations and reduced design review cycles. This research concludes that software integration of the signaling designs due to the efficiency and innovation of the selected computer drawing software and programming software language such as AutoCAD required less resources for computer drawings that are generated using automation tools compared to computer drawings that are generated manually. The resources required when automating the generation of signaling detailed designs are reduced for cable plans, book of circuits and source documents. This means that the business is optimized by utilizing less resources and subsequently delays are reduced during the design stage

Simulation combined model-based testing method for train control systems

A Train Control System (TCS) is utilised to guard the operational safety of the trains in railway systems. Therefore, functional testing is applied to verify consistency between the TCS and specification requirements. Traditional functional testing in TCSs is mainly based on manually designed test cases, which is becoming unsuitable for testing increasingly complex TCSs. Therefore, Model-Based Testing (MBT) methods have been introduced into TCS functional testing, to improve the efficiency and coverage of TCS testing, with application difficulties. To overcome the difficulties of applying MBT methods to test TCSs, the author introduces simulation combined MBT which combines an MBT method with simulation. Modelling method and implementation method for the proposed approach were explained in detail. Two case studies were undertaken to explore the effectiveness of the testing platform developed. The testing results obtained prove that the testing platform can be utilised to implement the functional testing of TCSs. To prove that the MBT platform is effective in detecting errors in the SUT, validation and verification was undertaken, which include validation of specification requirements and verification of the MBT platform. The testing performance is proven to be better than existing MBT methods in terms of coverage and efficiency

Empowered Youth: The Co-Creation of Youth as Technological Citizens and Consumers Within Community-Based Technology Programs

Thesis advisor: Stephen PfohlThe purpose of this study is to investigate the new media ecologies of urban, low-income youth and youth of color, and how they develop literacies and competencies around technology in the particular spaces of Community Technology Centers (CTCs), while placing them within their broader technological experiences and raced, classed, and gendered identities. This study builds on the concept of youth as experiencing a "new media ecology" in which youth engagement with technology is understood as a phenomenon which connects all spheres of experience. Through this work, I refine the understanding of how marginalized young people engage with technology in order to expand our understanding of digital inequality and its effects, as well as how digital inequality and inclusion interact with young people's identities and social worlds more broadly. Young people, marginalized by their raced, classes, and gendered identities, are both accused of being wasteful in their technology engagement, and are welcomed into these non-traditional learning spaces in order to cultivate their uses of technology into more meaningful and productive outcomes. There is a growing proliferation of informal and creative digital learning programs, and corresponding research and interrogation of the activities within these spaces. However, we lack a full and holistic understanding of who these young people are as technological citizens and consumers, an understanding that is necessary to inform effective interventions around digital inequality. Through qualitative research within two Boston-area Community Technology Centers, including participant observation and interviews, this study presents an analysis of how young people as agentic individuals interact with the contexts they enter into to produce new forms of agency and disempowerment. Rather than focusing on one area of the digital learning environment or youth technological experience, as other researchers have done, I delineate a more complete and dialogic view of less-advantaged young people and their technological engagement. My findings build on the need for supportive informal technology learning environments for marginalized youth, both in terms of providing stable environments with rich resources for technological exploration and skill-building, as well as providing learning environments which valorize and encourage youth agency and identity work. It is also necessary to recognize and allow for differences among youth in these spaces, who vary not only in terms of race, class, and gender, but also skills, abilities, interests, and motivations. I also call attention to the ways in which structural inequalities enter into these informal learning environments, resulting in their reproduction.Thesis (PhD) — Boston College, 2014.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Sociology

Makerspace Models and Organizational Policies for Technological Inclusion

In the early part of the 21st Century, discourses about the “Creative Economy” rose to prominence resulting in educational, economic, and policy initiatives supporting what became known generically as “makerspaces.” As interdisciplinary sites where arts, technology, design, and entrepreneurship meet, makerspaces were heralded as transformational organizational models for learning and innovation. This dissertation explores the social arrangements opened and foreclosed by makerspaces through ethnographic case studies of how different institutions introduced and adapted makerspace models from 2013-2019. Using a communicative ecology approach (Foth & Hearn, 2007), this study interrogates the structures and practices that shape participant experience of these collaborative media, technology, and design spaces, analyzes the construction of “maker literacies,” and traces the broader evolution of technology access concerns in the U.S. This study thereby contributes to the research literature on social production practices, technological literacy, and technological inequality as well as offering recommendations for similar initiatives. The Maker Movement refers to the early 2000s rise in visibility of Do-It-Yourself (DIY) “making” activities aided by the advent of publications such as Make magazine, online communities such as Instructables, in-person meetups called Maker Faires, and localized communities of practice in makerspaces. Unfortunately, many of the independent makerspaces that were opened during the height of The Maker Movement from 2011-2016 have since closed due to leadership issues, funding shortfalls, and other organizational challenges. As of 2019, libraries, universities, schools, and museums are the most common places to find makerspaces. Rather than a unique phenomenon, makerspaces are conceptualized here as an evolution and re-branding of community access points for social inclusion like that of the community technology centers (CTCs) that arose throughout the U.S. when policy concerns for “digital divides” were at their height. Examining these spaces from a communication perspective as part of a longer history of technology access initiatives reveals how emerging technologies continually reorganize activities and influence priorities for organizations with social inclusion goals. Through in-depth case studies of three makerspaces in Massachusetts with different institutional ties—a community access media center, a public library, and an economic/community development project—this study explores the contributions of makerspaces to local ecologies with special attention to how media and technological literacies are enacted in makerspace initiatives. In particular, the study documents how policies and practices shape participation through questioning the impetus for creating a makerspace and what activities are recognized and valued in these spaces. The study also explores the sustainability of initiatives concerned with media and technological literacies amidst the changing terrain of digital inequality in the U.S. While political and economic transformations in the U.S. continually change access initiative priorities, interrogating discourses related to digital inequality, creativity, and innovation are still important for supporting equitable community development. A fuller understanding of the promises and pitfalls of the makerspace approach will enrich our understanding of social values related to technology and may be used to inform media and technological literacy initiatives

Use Of Integrated Training Environments To Sustain Army Warfighting Proficiency In An Era Of Constrained Resources: Understanding What\u27s Required To Win The First Battle Of The Next Conflict

This research investigates the current state and ability of homestation training infrastructure (TADSS, networks, and facilities) and framework for training (scenarios, databases, and training support packages) to support a Live Virtual Constructive – Integrating Architecture (LVC-IA) delivered Integrated Training Environment (ITE). As combat operations in Central and Southwest Asia come to a close the Army is faced with extreme post-conflict budget cuts and force reductions. Continued evolution of Army training methodology is required to overcome limited resources and maintain force readiness in the anticipated “era of persistent conflict”. A LVC-IA delivered ITE promises to be the next step in the evolution of training. Interoperation of live, virtual, and constructive simulations in a persistent and consistent manner can collectively train brigade and below units on combined arms tasks in a resource constrained homestation environment. However, LVC-IA cannot act alone in establishing the ITE. Prior to the fielding of LVC-IA, local installations must already possess a training infrastructure that optimizes training resources as well as a framework for training that meets Operational Adaptability training requirements. To measure the perceived state and ability of homestation training infrastructure and framework for training to support a LVC-IA delivered ITE, a survey was conducted of homestation training community members at the 18 Army installations scheduled for LVC-IA fielding. Additionally, perceptions regarding the role of LVC-IA in establishing the ITE and emerging resources, useful in the development of local framework for training were sought. Findings, conclusions, limitations, lessons learned, and recommendations for future research are presented

PROGRAM and PROCEEDINGS THE NEBRASKA ACADEMY OF SCIENCES: 139th Anniversary Year, One Hundred-Twenty-Ninth Annual Meeting, April 12, 2019, NEBRASKA WESLEYAN UNIVERSITY, LINCOLN, NEBRASKA

PROGRAM AT-A-GLANCE FRIDAY, APRIL 12, 2019 7:30 a.m. REGISTRATION OPENS - Lobby of Lecture Wing, Olin Hall 8:00 Aeronautics and Space Science, Session A – Acklie 109 Aeronautics and Space Science, Session B – Acklie 111 Collegiate Academy; Biology, Session B - Olin B Biological and Medical Sciences, Session A - Olin 112 Biological and Medical Sciences, Session B - Smith Callen Conference Center Chemistry and Physics; Chemistry - Olin A 8:00 “Teaching and Learning the Dynamics of Cellular Respiration Using Interactive Computer Simulations” Workshop – Olin 110 9:30 “Life After College: Building Your Resume for the Future” Workshop – Acklie 218 8:25 Collegiate Academy; Chemistry and Physics, Session A – Acklie 007 8:36 Collegiate Academy; Biology, Session A - Olin 111 9:00 Chemistry and Physics; Physics – Acklie 320 9:10 Aeronautics and Space Science, Poster Session – Acklie 109 & 111 10:30 Aeronautics and Space Science, Poster Session – Acklie 109 & 111 11:00 MAIBEN MEMORIAL LECTURE: Dr David Swanson - OLIN B Scholarship and Friend of Science Award announcements 12:00 p.m. LUNCH – WESLEYAN CAFETERIA Round-Table Discussion – “Assessing the Academy: Current Issues and Avenues for Growth” led by Todd Young – Sunflower Room 12:50 Anthropology – Acklie 109 1:00 Applied Science and Technology - Olin 111 Biological and Medical Sciences, Session C - Olin 112 Biological and Medical Sciences, Session D - Smith Callen Conference Center Chemistry and Physics; Chemistry - Olin A Collegiate Academy; Biology, Session B - Olin B Earth Science – Acklie 007 Environmental Sciences – Acklie 111 Teaching of Science and Math – Acklie 218 1:20 Chemistry and Physics; Physics – Acklie 320 4:30 BUSINESS MEETING - OLIN B NEBRASKA ASSOCIATION OF TEACHERS OF SCIENCE (NATS) The 2019 Fall Conference of the Nebraska Association of Teachers of Science (NATS) will be held at the Younes Conference Center, Kearney, NE, September 19-21, 2019. President: Betsy Barent, Norris Public Schools, Firth, NE President-Elect: Anya Covarrubias, Grand Island Public Schools, Grand Island, NE AFFILIATED SOCIETIES OF THE NEBRASKA ACADEMY OF SCIENCES, INC. 1. American Association of Physics Teachers, Nebraska Section Web site: http://www.aapt.org/sections/officers.cfm?section=Nebraska 2. Friends of Loren Eiseley Web site: http://www.eiseley.org/ 3. Lincoln Gem & Mineral Club Web site: http://www.lincolngemmineralclub.org/ 4. Nebraska Chapter, National Council for Geographic Education 5. Nebraska Geological Society Web site: http://www.nebraskageologicalsociety.org Sponsors of a $50 award to the outstanding student paper presented at the Nebraska Academy of Sciences Annual Meeting, Earth Science /Nebraska Chapter, Nat\u27l Council Sections 6. Nebraska Graduate Women in Science 7. Nebraska Junior Academy of Sciences Web site: http://www.nebraskajunioracademyofsciences.org/ 8. Nebraska Ornithologists’ Union Web site: http://www.noubirds.org/ 9. Nebraska Psychological Association http://www.nebpsych.org/ 10. Nebraska-Southeast South Dakota Section Mathematical Association of America Web site: http://sections.maa.org/nesesd/ 11. Nebraska Space Grant Consortium Web site: http://www.ne.spacegrant.org