Parallel ruptures: Jews of Bessarabia and Transnistria between Romanian nationalism and Soviet communism, 1918-1940

“Parallel Ruptures: Jews of Bessarabia and Transnistria between Romanian Nationalism and Soviet Communism, 1918-1940,” explores the political and social debates that took place in Jewish communities in Romanian-held Bessarabia and the Moldovan Autonomous Soviet Socialist Republic during the interwar era. Both had been part of the Russian Pale of Settlement until its dissolution in 1917; they were then divided by the Romanian Army’s occupation of Bessarabia in 1918 with the establishment of a well-guarded border along the Dniester River between two newly-formed states, Greater Romania and the Soviet Union. At its core, the project focuses in comparative context on the traumatic and multi-faceted confrontation with these two modernizing states: exclusion, discrimination and growing violence in Bessarabia; destruction of religious tradition, agricultural resettlement, and socialist re-education and assimilation in Soviet Transnistria. It examines also the similarities in both states’ striving to create model subjects usable by the homeland, as well as commonalities within Jewish responses on both sides of the border. Contacts between Jews on either side of the border remained significant after 1918 despite the efforts of both states to curb them, thereby necessitating a transnational view in order to examine Jewish political and social life in borderland regions. The desire among Jewish secular leaders to mold their co-religionists into modern Jews reached across state borders and ideological divides and sought to manipulate respective governments to establish these goals, however unsuccessful in the final analysis. Finally, strained relations between Jews in peripheral borderlands with those at national/imperial cores, Moscow and Bucharest, sheds light on the complex circumstances surrounding the inclusion versus exclusion debates at the heart of all interwar European states and the complicated negotiations that took place within all minority communities that responded to state policies.

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.