Scheduling of track inspection and maintenance activities in railroad networks

The U.S. railroad companies spend billions of dollars every year on railroad track maintenance in order to ensure safety and operational efficiency of their railroad networks. Besides maintenance costs, other costs such as train accident costs, train and shipment delay costs and rolling stock maintenance costs are also closely related to track maintenance activities. Optimizing the track maintenance process on the extensive railroad networks is a very complex problem with major cost implications. Currently, the decision making process for track maintenance planning is largely manual and primarily relies on the knowledge and judgment of experts. There is considerable potential to improve the process by using operations research techniques to develop solutions to the optimization problems on track maintenance. In this dissertation study, we propose a range of mathematical models and solution algorithms for three network-level scheduling problems on track maintenance: track inspection scheduling problem (TISP), production team scheduling problem (PTSP) and job-to-project clustering problem (JTPCP). TISP involves a set of inspection teams which travel over the railroad network to identify track defects. It is a large-scale routing and scheduling problem where thousands of tasks are to be scheduled subject to many difficult side constraints such as periodicity constraints and discrete working time constraints. A vehicle routing problem formulation was proposed for TISP, and a customized heuristic algorithm was developed to solve the model. The algorithm iteratively applies a constructive heuristic and a local search algorithm in an incremental scheduling horizon framework. The proposed model and algorithm have been adopted by a Class I railroad in its decision making process. Real-world case studies show the proposed approach outperforms the manual approach in short-term scheduling and can be used to conduct long-term what-if analyses to yield managerial insights. PTSP schedules capital track maintenance projects, which are the largest track maintenance activities and account for the majority of railroad capital spending. A time-space network model was proposed to formulate PTSP. More than ten types of side constraints were considered in the model, including very complex constraints such as mutual exclusion constraints and consecution constraints. A multiple neighborhood search algorithm, including a decomposition and restriction search and a block-interchange search, was developed to solve the model. Various performance enhancement techniques, such as data reduction, augmented cost function and subproblem prioritization, were developed to improve the algorithm. The proposed approach has been adopted by a Class I railroad for two years. Our numerical results show the model solutions are able to satisfy all hard constraints and most soft constraints. Compared with the existing manual procedure, the proposed approach is able to bring significant cost savings and operational efficiency improvement. JTPCP is an intermediate problem between TISP and PTSP. It focuses on clustering thousands of capital track maintenance jobs (based on the defects identified in track inspection) into projects so that the projects can be scheduled in PTSP. A vehicle routing problem based model and a multiple-step heuristic algorithm were developed to solve this problem. Various side constraints such as mutual exclusion constraints and rounding constraints were considered. The proposed approach has been applied in practice and has shown good performance in both solution quality and efficiency.

Nietzsche's orphans: music and the search for unity in revolutionary Russia, 1905-1921

At the dawn of the twentieth century, Imperial Russia was in the throes of immense social, political and cultural upheaval. The effects of rapid industrialization, rising capitalism and urbanization, as well as the trauma wrought by revolution and war, reverberated through all levels of society and every cultural sphere. In the aftermath of the 1905 revolution, amid a growing sense of panic over the chaos and divisions emerging in modern life, a portion of Russian educated society (obshchestvennost’) looked to the transformative and unifying power of music as a means of salvation from the personal, social and intellectual divisions of the contemporary world. Transcending professional divisions, these “orphans of Nietzsche” comprised a distinct aesthetic group within educated Russian society. While lacking a common political, religious or national outlook, these philosophers, poets, musicians and other educated members of the upper and middle strata were bound together by their shared image of music’s unifying power, itself built upon a synthesis of Russian and European ideas. They yearned for a “musical Orpheus,” a composer capable of restoring wholeness to society through his music. My dissertation is a study in what I call “musical metaphysics,” an examination of the creation, development, crisis and ultimate failure of this Orphic worldview. To begin, I examine the institutional foundations of musical life in late Imperial Russia, as well as the explosion of cultural life in the aftermath of the 1905 Revolution, a vibrant social context which nourished the formation of musical metaphysics. From here, I assess the intellectual basis upon which musical metaphysics rested: central concepts (music, life-transformation, theurgy, unity, genius, nation), as well as the philosophical heritage of Nietzsche and the Christian thinkers Vladimir Solov’ev, Aleksei Khomiakov, Ivan Kireevskii and Lev Tolstoi. Nietzsche’s orphans’ struggle to reconcile an amoral view of reality with a deeply felt sense of religious purpose gave rise to neo-Slavophile interpretations of history, in which the Russian nation (narod) was singled out as the savior of humanity from the materialism of modern life. This nationalizing tendency existed uneasily within the framework of the multi-ethnic empire. From broad social and cultural trends, I turn to detailed analysis of three of Moscow’s most admired contemporary composers, whose individual creative voices intersected with broader social concerns. The music of Aleksandr Scriabin (1871-1915) was associated with images of universal historical progress. Nikolai Medtner (1879-1951) embodied an “Imperial” worldview, in which musical style was imbued with an eternal significance which transcended the divisions of nation. The compositions of Sergei Rachmaninoff (1873-1943) were seen as the expression of a Russian “national” voice. Heightened nationalist sentiment and the impact of the Great War spelled the doom of this musical worldview. Music became an increasingly nationalized sphere within which earlier, Imperial definitions of belonging grew ever more problematic. As the Germanic heritage upon which their vision was partially based came under attack, Nietzsche’s orphans found themselves ever more divided and alienated from society as a whole. Music’s inability to physically transform the world ultimately came to symbolize the failure of Russia’s educated strata to effectively deal with the pressures of a modernizing society. In the aftermath of the 1917 revolutions, music was transformed from a symbol of active, unifying power into a space of memory, a means of commemorating, reinterpreting, and idealizing the lost world of Imperial Russia itself.