IMPASS is a novel spoke-wheel robot invented by researchers at the Robotics and Mechanisms Lab (RoMeLa) at Virginia Tech. The robot is driven by a rimless spoke wheel which can alter the length of any given spoke in the hub. This form of novel locomotion combines the efficiency of a wheeled robot and the mobility of a legged robot, arriving at a very practical mobility platform. A highly mobile robot such as IMPASS could prove very valuable in applications where the terrain is complex and dangerous, such as search and rescue, reconnaissance, or anti-terror response. A prototype has been constructed that effectively demonstrates the actuated spoke wheel concept using two wheels containing six spokes each. Manually controlling the motion of two wheels and twelve spokes would be a daunting task for any operator. Due to this inherent complexity, automated motion control is a necessity for the IMPASS platform. The work presented here will discuss two different approaches to the motion planning problem for the two-dimensional sagittal plane. The first approach is deliberative in nature and depends on fairly accurate terrain sensing. The motion planning first decides on a set of contact points based on obstacle configurations and a Lagrangian interpolation of the terrain. A lower level motion planning component then executes the movements that guide the spoke ends to the contact points. The second motion planning approach is reactive in nature. Proprioceptive and tactile sensors are used to determine the robot's pose and immediate surroundings. These sensors directly affect the motion profile of the robot. The reactive approach follows much simpler logic, which theoretically will make it more robust. Motion planning strategies were tested in simulation and on the IMPASS prototype. Both strategies proved to be well suited for different applications. The deliberative control was very successful in a structured environment, whereas the reactive control was able to cross a wider variety of terrain. The results from the testing also provided some insight into variables introduced by the hardware. Future improvements to the motion planning control include accounting for these variables in the hardware and eventually developing three-dimensional motion planning algorithms based on the lessons learned from the two-dimension case. / Master of Science

Abstract Background: Over the last few years, the principle of cross-docking has prominently spreadthrough the companies in which they try hard to make their supply chain channels efficientand achieve higher demands of the society. Studies claimed that inventory management remains to be challenge for professionals of supply chain as long-term processing times may result in considerable financial losses for firms. Aim: This research aims to evaluate the effectiveness of Hub-and-Spoke cross-dockingstrategy in inventory management by understanding the impact, outcomes or efficacy of its implementation. Methodology: This research has adopted qualitative research method to generate extensive data and deep insights to underlying factors behind organizations' decisions and behavior on the implementation of cross-docking concept. The interviews have been chosen as the main data collection method of this research because it has been used successfully in order to produce rich and detailed information about the participants in the supply chain management.The total sample size of the participants is 10. For instance, the research conducted interviews via In-person, Zoom and WhatsApp video calls. The researcher recruited supply chain managers including companies’ representatives, supply chain practitioners, logistic managers,inventory managers and related stakeholders responsible for executing and overviewing inventory management approaches within their firms operating in Sweden. Thus, individuals can offer useful information related to supply planning, implementing and optimising cross-docking operations within their organisations. Findings and Conclusion: The research has, however, led to the impact of the organizational culture on the sustainable Hub-and-Spoke cross-docking strategy with the participants, all agreeing on the role that culture plays in shaping the structure of the strategy in the long-term. Finally, organizational culture was considered to be the cornerstone system,emphasizing the values of innovation, collaboration, transparency, and employee empowerment that serve as the driving force for its application. Participants highlighted the significance of facilitating discussions on various levels, recognizing the importance of collaborations and teams, establishing training and development systems, creating the culture of continuous improvement, and empowering employees as key measures utilized in dealing with the organizational culture challenges in cross-docking implementation and sustainability. KPIs for the cross-dock's level of success and effectiveness include order fulfillment rates,inventory turnover and customer satisfaction, compliance, employee satisfaction, operational efficiency, and the practice of ethical business conduct and corporate values. Thus, thisresearch proves the connection between the organizational culture and best productivity ,results of cross-docking. This makes it clear that a supportive environment is important for a continued performance in cross-docking operations.

No description available.

A less-than-truckload (LTL) carrier typically delivers shipments less than 10,000 pounds (classified as LTL shipment). The size of the shipment in LTL networks provides ample opportunities for consolidation. LTL carriers have focused on hub-and-spoke based consolidation to realize economies of scale. Generally, hub-and-spoke systems work as follows: the shipment is picked up from the shipper and brought to an origin terminal, which is the entry point into the hub-and-spoke system. From the terminal, the freight is sent to the first hub, where it is sorted and consolidated with other shipments, and then sent on to a second hub. It is finally sent from the second hub to the destination terminal, which is the exit point of the hub-and-spoke system. However, the flow of shipments is often more complicated in practice. In an attempt to reduce sorting costs, load planners sometimes take this hub-and-spoke infrastructure and modify it considerably to maximize their truck utilization while satisfying service constraints. Decisions made by a load planner may have a cascading effect on load building throughout the network. As a result, decentralized load planning may result in expensive global solutions. Academic as well as industrial researchers have adapted a hierarchical approach to design the hub-and-spoke networks: generate the hub-and-spoke network, route shipments within this hub-and-spoke network (generate a load plan) and finally, balance the empty trailers. We present mathematical models and heuristics for each of the steps involved in the design of the hub-and-spoke network. The heuristics are implemented in a user-friendly graphical tool that can help understand patterns of freight flow and provide insights into the design of the hub-and-spoke network. We also solved the load planning sub-problem in a parallel computation environment to achieve significant speed-ups. Because of the quick solution times, the tool lays the foundation to address pressing further research questions such as deciding location and number of hubs. We have used data provided by Roadway Parcel Services, Inc. (RPS), now FedEx Ground, as a case-study for the heuristics. Our solutions rival the existing industry solutions which have been a product of expensive commercial software and knowledge acquired by the network designers in the industry.

Transportation is one of the most vital services in modern society. It makes most of the other functions of society possible. Real transportation systems are so large and complex that in order to build the science of transportation systems it will be necessary to work in many areas, such as: Modeling, Optimization and Simulation. We are interested in solutions for the so-called fleet-sizing-and-allocation problem (FSAP). Fleet sizing and allocation problems are one of the most interesting and hard to solve logistic problems. A fleet sizing and allocation problem consists of two interdependent parts. The fleet sizing problem is to determine a number of transportation units that optimally balances service requirements against the cost of purchasing and maintaining the transportation units. The allocation problem is dealing with the repositioning of transportation units to serve future transportation demand. To make the fleet sizing and allocation problem a little bit more tractable we concentrate on logistic systems with a special hub-and-spoke structure. We start with a very simple fleet sizing of one-to-one case. This case will cause us to focus attention on several key issues in fleet sizing. Afterwards, the generalization of the one-to-one system is the one-to-many system. As a simple example can serve the continuous time situation where a single origin delivers items to many destinations. For the case that items are produced in a deterministic production cycle and transportation times are stochastic. We also studied a hub-and-spoke problem with continuous time and stochastic demand. To solve this problem, based on Marginal Analysis, we applied queueing theory methods. The investigation of the fleet-sizing-and-allocation problem for hub-and-spoke systems is started for a single-period, deterministic-demand model. In that the model hub has to decide how to use a given number of TU’s to satisfy a known (deterministic) demand in the spokes. We consider two cases: 1. Renting of additional TU’s from outside the system is not possible, 2. Renting of additional TU’s from outside the system is possible. For each case, based on Marginal Analysis, we developed a simple algorithm, which gives us the cost-minimal allocation. Since the multi-period, deterministic demand problem is NP-hard we suggest to use Genetic Algorithms. Some building elements for these are described. For the most general situation we also suggest to use simulation optimization. To realize the simulation optimization approach we could use the software tool “Calculation Assessment Optimization System” (CAOS). The idea of CAOS is to provide a software system, which separates the optimization process from the optimization problem. To solve an optimization problem the user of CAOS has to build up a model of the system to which the problem is related. Furthermore he has to define the decision parameters and their domain. Finally, we used CAOS for two classes of hub-and-spoke system: 1. A single hub with four spokes, 2. A single hub with fifty spokes. We applied four optimizers – a Genetic Algorithm, Tabu Search, Hybrid Parallel and Hybrid Serial with two distributions (Normal Distribution and Exponential Distribution) for a customer interarrival times and their demand.

Univ., Diss.--Paderborn, 2002.

Hub and Spoke systems, is a important research area in localization theory. This occur, because of these systems are very used in logistics problems, e.g., telecommunication networks and transport of passenger and load.To serve the demand of each pair source destination, basically, the Hub and Spoke system replaces direct connections between the pairs for a hubs network. These hubs group the traffic sharing the transportation medium. To get the best hubs configuration is necessary efficient methods, because this problem, hubs allocation, is a NP-problem. In this work was developed an parallel implementation of the Benders Decomposition method for the uncapacitated multiple allocation hub location problem. In our implementation we use the Skorin- Kapov model. The parallel implementation of Benders Decomposition for hub and spoke problem is not known in literature. The results show that the parallel approach is applicable and more efficient that nonparallel one. The experiments reveals that the parallel algorithm had a time execution 70% minor when compared with the nonparallel one. / Sistemas do tipo eixo raio, tornaram-se uma importante área de pesquisa da teoria de localização nas últimas décadas. Esse destaque deve-se em grande parte ao sucesso de sua utilização em sistemas logísticos, tanto de transporte de passageiros quanto de cargas, e em redes de telecomunicações. Ao invés de servir cada par origem destino de demanda com uma conexão direta, sistemas do tipo eixo raio substituem essas conexões diretas por uma rede de concentradores. Esses concentradores permitem que o tráfego seja agrupado e transportado através de um meio de transporte compartilhado, para ser então entregue aos respectivos destinos. Sendo um problema NP, é necessário o uso de métodos eficientes para sua resolução. Neste trabalho, é desenvolvida uma implementação em paralelo do método de Decomposição de Benders para o problema de localização de concentradores de alocação múltipla não capacitados. A implementação em paralelo do método de Decomposição de Benders para o problema eixo raio não é conhecido na literatura, entretanto os bons resultados obtidos pelo algoritmo paralelo desenvolvido revelam que a abordagem paralela é aplicável e mais eficiente. Nos experimentos realizados, o algoritmo paralelo apresentou um tempo de resposta até 70% menor que o tempo de resposta do algoritmo seqüencial.

As the world changes because of the globalization, the environment of the aviation changes as well. The airlines are forced to adapt to these changes and choose new strategies to operate successfully. The main objective of this thesis is to, according to the title, describe, identify and explain the processes which significantly affect current image of the world of aviation and focus on four Central European legacy carriers. The issues of globalization and its affect on behavior of economic actors, which airlines are, are discussed as first. The following part is dedicated to the characteristics of aviation and its components, the milieu and the behavior of the airlines as well as the newest strategic trends that are being chosen is described as well. The theoretical part is followed by the empirical one where the particular steps of examined airlines are analyzed and explained. The hypotheses concerning the probable behavior and adopted strategies of four analyzed carriers are expressed according to the discovered theoretical principles of the operations of current legacy (network) carriers. Whether the hypotheses are completely or partially confirmed, is discussed at the end of the empirical chapter. Key words: globalization, air transport, legacy carriers, airline alliances, hub and spoke, codeshare

Hierdie studie stel ondersoek in na die voorkoms en funksie van spookkarakters in die roman-oeuvre van Etienne van Heerden, een van Afrikaanse letterkunde se mees bekroonde skrywers. Die doel van hierdie studie is om vas te stel watter funksies die spookkarakters in onderskeidelik Toorberg (1986), Die Stoetmeester (1993) en Die swye van Mario Salviati (2000) vervul, en ook of die spookkarakters in hierdie romans ʼn groter funksie buiten dié in hul onderskeie tekste vervul wat nuwe lig kan werp op Etienne van Heerden se hantering van identiteit (ʼn tema wat deurlopend in sy oeuvre na vore kom). Die ondersoek word hoofsaaklik aan die hand van teks- en romananalise gedoen. Die spookkarakters in die betrokke romans word geklassifiseer aan die hand van teorie uit die paranormale wetenskap. Alhoewel die spookkarakters en die tersaaklike romans nie genregebonde gelees word nie, word teorie uit karakterstudies, identiteitstudies, spookstories, die Gotiese, die magiese realisme, die postkolonialisme, die historiese roman en liminaliteitsteorie in die bespreking betrek. Dit word geargumenteer dat die spookkarakters in Toorberg die prototipiese, manlike Afrikaneridentiteit vergestalt en dit deur middel van uitsluiting (eksklusiwiteit) in stand hou; dat die spookkarakter in Die Stoetmeester ʼn liminale figuur in ʼn liminale historiese tydperk vergestalt, en derhalwe ʼn liminale weergawe van Afrikaneridentiteit uitbeeld; en dat die spookkarakters in Die swye van Mario Salviati ʼn meer inklusiewe (Suid-)Afrikaanse identiteit uitbeeld deur identiteite in die Suid-Afrikaanse verlede wat voorheen misken is, in spesifieke spookkarakters te vergestalt. Deur die individuele spookkarakters as verteenwoordigend van groepsidentiteite te lees binne die bepaalde historiese konteks waarin die romans afspeel en gepubliseer is, word daar ten slotte aangevoer dat die spookkarakters in die roman-oeuvre van Etienne van Heerden ʼn evolusie van Afrikaner- na Suid-Afrikaanse identiteit uitbeeld. / PhD (Afrikaans and Dutch), North-West University, Potchefstroom Campus, 2015

Hierdie studie stel ondersoek in na die voorkoms en funksie van spookkarakters in die roman-oeuvre van Etienne van Heerden, een van Afrikaanse letterkunde se mees bekroonde skrywers. Die doel van hierdie studie is om vas te stel watter funksies die spookkarakters in onderskeidelik Toorberg (1986), Die Stoetmeester (1993) en Die swye van Mario Salviati (2000) vervul, en ook of die spookkarakters in hierdie romans ʼn groter funksie buiten dié in hul onderskeie tekste vervul wat nuwe lig kan werp op Etienne van Heerden se hantering van identiteit (ʼn tema wat deurlopend in sy oeuvre na vore kom). Die ondersoek word hoofsaaklik aan die hand van teks- en romananalise gedoen. Die spookkarakters in die betrokke romans word geklassifiseer aan die hand van teorie uit die paranormale wetenskap. Alhoewel die spookkarakters en die tersaaklike romans nie genregebonde gelees word nie, word teorie uit karakterstudies, identiteitstudies, spookstories, die Gotiese, die magiese realisme, die postkolonialisme, die historiese roman en liminaliteitsteorie in die bespreking betrek. Dit word geargumenteer dat die spookkarakters in Toorberg die prototipiese, manlike Afrikaneridentiteit vergestalt en dit deur middel van uitsluiting (eksklusiwiteit) in stand hou; dat die spookkarakter in Die Stoetmeester ʼn liminale figuur in ʼn liminale historiese tydperk vergestalt, en derhalwe ʼn liminale weergawe van Afrikaneridentiteit uitbeeld; en dat die spookkarakters in Die swye van Mario Salviati ʼn meer inklusiewe (Suid-)Afrikaanse identiteit uitbeeld deur identiteite in die Suid-Afrikaanse verlede wat voorheen misken is, in spesifieke spookkarakters te vergestalt. Deur die individuele spookkarakters as verteenwoordigend van groepsidentiteite te lees binne die bepaalde historiese konteks waarin die romans afspeel en gepubliseer is, word daar ten slotte aangevoer dat die spookkarakters in die roman-oeuvre van Etienne van Heerden ʼn evolusie van Afrikaner- na Suid-Afrikaanse identiteit uitbeeld. / PhD (Afrikaans and Dutch), North-West University, Potchefstroom Campus, 2015