Merging smart card data and train movement data: How to assign trips to trains?

This report explains the assignment method applied to link trips compiled in smart card data to train movements recorded in the signalling system. Particular attention has been paid to (1) origin-destination pairs with multiple potential route options, (2) peak-hour trips delayed by di culties in boarding crowded trains at the origin station, and (3) trips originating or ending on rail lines not included in the train movement dataset. In the current version of this paper the metro network on which the method has been applied is anonymised

Skinner and Rosanvallon: Reconciling the History of Political Thought with Political Philosophy*

This paper addresses the issue of whether a proper history of political thought should avoid any contact with substantive political philosophy, as it was vehemently claimed earlier by Cambridge historians of political thought, or not. It argues that (A) a strong political or philosophical bias might kill the credibility of a reliable history of political thought, but (B), in this genre, it is by definition impossible to avoid taking on board politico-philosophical concerns. What is more, the paper also tries to show (C) the relevance of political philosophy for the history of political thought and vice versa. In particular, it will argue along the following two lines: (a) Without a political philosophical self-positioning any reconstruction of the history of political thought remains underdetermined and therefore uninstructive, and (b) without a look at the history of political thought political philosophy remains blind, alienated, theoretically unfounded and therefore potentially even dangerous.Methodologically, the paper aims to recapture some of the conclusions of the debates of the relationship of the two disciplines, with special attention to the French and British contexts (more particularly to the oeuvres of Rosanvallon and Skinner).Artykuł podejmuje zagadnienie czy właściwa historia myśli politycznej powinna wystrzegać się wszelkiego kontaktu z poważną filozofią polityczną, którego to stanowiska żarliwie bronili wcześniej historycy myśli politycznej z Cambridge, czy też nie. Przedstawiono tu pogląd, że silna stronniczość w dziedzinie polityki czy filozofii może zniszczyć wiarygodność miarodajnej historii myśli politycznej, ale uprawiając tę naukę z definicji nie sposób uchronić się przed rozważaniami polityczno-filozoficznymi. Artykuł próbuje także wykazać związek filozofii politycznej z historią myśli politycznej i vice versa. Artykuł szczególnie koncentruje się na następujących dwóch twierdzeniach: (a) wszelka rekonstrukcja historii myśli politycznej pozbawiona własnej pozycji polityczno-filozoficznej jest nieokreślona i dlatego nie stanowi źródła wiedzy, (b) bez przyjrzenia się historii myśli politycznej filozofia polityczna jest ślepa, wyobcowana, nieuzasadniona teoretycznie, a tym samym nawet potencjalnie niebezpieczna.Z metodologicznego punktu widzenia w artykule podjęto próbę ponownego ujęcia niektórych wniosków z rozważań na temat związku obu dyscyplin ze szczególnym uwzględnieniem kontekstu francuskiego i angielskiego (a konkretnie dzieł Rosanvallona i Skinnera)

Conservation of Limited Resources: Design Principles for Security and Usability on Mobile Devices

Mobile devices have evolved from an accessory to the primary computing device for an increasing portion of the general population. Not only is mobile the primary device, consumers on average have multiple Internet-connected devices. The trend towards mobile has resulted in a shift to “mobile-first” strategies for delivering information and services in business organizations, universities, and government agencies. Though principles for good security design exist, those principles were formulated based upon the traditional workstation configuration instead of the mobile platform. Security design needs to follow the shift to a “mobile-first” emphasis to ensure the usability of the security interface. The mobile platform has constraints on resources that can adversely impact the usability of security. This research sought to identify design principles for usable security for mobile devices that address the constraints of the mobile platform. Security and usability have been seen as mutually exclusive. To accurately identify design principles, the relationship between principles for good security design and usability design must be understood. The constraints for the mobile environment must also be identified, and then evaluated for their impact on the interaction of a consumer with a security interface. To understand how the application of the proposed mobile security design principles is perceived by users, an artifact was built to instantiate the principles. Through a series of guided interactions, the importance of proposed design principles was measured in a simulation, in human-computer interaction, and in user perception. The measures showed a resounding difference between the usability of the same security design delivered on mobile vs. workstation platform. It also reveals that acknowledging the constraints of an environment and compensating for the constraints yields mobile security that is both usable and secure. Finally, the hidden cost of security design choices that distract the user from the surrounding environment were examined from both the security perspective and public safety perspective

E-Bike Engagement and Accessibility

ME450 Capstone Design and Manufacturing Experience: Winter 2021There is currently a large barrier of entry to the design space surrounding a DIY E-bike retrofit build. The combination of necessary knowledge regarding gearing and transmission, mechatronics and motor control, battery charge and capacity, and force analyses, all in addition to general bike-related knowledge can be completely overwhelming to a novice user. Our team approached this project through a Socially-Engaged Design strategy to provide access, regardless of mechanical ability and budget, to a low-cost and easily accessible E-bike. We defined requirements for our solution design to incentivize the use, purchase or build of E-bikes, to be usable without much background knowledge, to be safe, to be attractive and accessible to the user, and to be inexpensive. We began our design process by conducting research on existing designs solutions. From here, we conveyed every step that a user would go through to access an E-bike themselves and how they could optimize an E-bike or E-bike retrofit of their own. Our theoretical stakeholder persona for this project is a University of Michigan student looking to commute across campus daily. This persona helped us build specifications such as hill climb ability, battery life and a target max flat ground speed. Primary subsystems were identified as system controls like throttling or pedal assist, motor and transmission, power supply, and the mounting interface. Our final CAD model of this design and its subsystems includes the motor, power supply, transmission, housing, and interfaces for any other subsystem. We also developed a model for a sustainable modular battery prototype design. This accomplishes our aim to make each battery cell replaceable while achieving a high cycle life compared to other batteries of similar size and cost. The transmission design solution provides a smooth ride up the steepest Ann Arbor hills and its mounting design provides easy access for maintenance and diagnosability. After completing the design, we evaluated it against our set specifications through physical testing and virtual analysis. We also examined the effectiveness of our design solution by evaluating the gap between existing market solutions and the user needs. Through our analysis, we realized that our retrofit design is a helpful tool to convey our DIY decision making process, though its mechanical complexity prevented it from properly addressing our defined need for increased E-bike accessibility. To effectively address the needs of our problem space, we determined that we should communicate our process to users through inclusive web design, rather than only conveying it through the prototype design. We therefore developed a website which takes the user through several pages covering our mission statement, E-bike related background information, evaluation criteria for E-Bike selection, the design and decision-making process, maintenance guides and safety practices, end-of-life recycling details, and opportunities for further customization of a DIY retrofit build. We validated our website solution against several inclusive web design and educational guidelines which include the Nielsen Norman group and the US Department of Education. While the website needs further building and revision for optimal accessibility, these verification techniques indicate that its framework and existing structure will help users access, regardless of mechanical ability and budget, to a low-cost and easily accessible E-bike. In the future, we plan to finalize a website design with the use of HTML and CSS programming and conduct usability tests with potential users to iterate on our design and improve it further.http://deepblue.lib.umich.edu/bitstream/2027.42/167638/1/Team_21-E-Bike_Engagement_and_Accessibility.pd

Formal Specification and Testing of a Management Architecture

The importance of network and distributed systems management to supply and maintain services required by users has led to a demand for management facilities. Open network management is assisted by representing the system resources to be managed as objects, and providing standard services and protocols for interrogating and manipulating these objects. This paper examines the application of formal description techniques to the specification of managed objects by presenting a case study in the specification and testing of a management architecture. We describe a formal specification of a management architecture suitable for scheduling and distributing services across nodes in a distributed system. In addition, we show how formal specifications can be used to generate conformance tests for the management architecture

Testing refinements by refining tests

One of the potential benefits of formal methods is that they offer the possibility of reducing the costs of testing. A specification acts as both the benchmark against which any implementation is tested, and also as the means by which tests are generated. There has therefore been interest in developing test generation techniques from formal specifications, and a number of different methods have been derived for state based languages such as Z, B and VDM. However, in addition to deriving tests from a formal specification, we might wish to refine the specification further before its implementation. The purpose of this paper is to explore the relationship between testing and refinement. As our model for test generation we use a DNF partition analysis for operations written in Z, which produces a number of disjoint test cases for each operation. In this paper we discuss how the partition analysis of an operation alters upon refinement, and we develop techniques that allow us to refine abstract tests in order to generate test cases for a refinement. To do so we use (and extend existing) methods for calculating the weakest data refinement of a specification