ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper tries to discuss the mobility management when Internet technology is applied along the whole path from spacecraft to ultimate customers in ground. In addition to Mobile IP protocol, micromobility solution is introduced during cross-support. Those competing micromobility solutions in mobile network research area are compared to select one that is most suitable to space network topology characteristics and operation traditions. Other issues are also taken into account, such as deployment and compatibility with Mobile IP when cross-support is not provided. Simulation comparison for hand-off performance with and without micro-mobility solution during cross-support is presented to justify our proposition.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The increasing of space explorations requires space communication protocols to provide more capabilities, such as dynamic routing, adaptive data transformation and automatic resource allocation. Accordingly, a universal space communication protocol stack should be provided instead of specially designing protocol for given space mission. Considering the requirements and characters of space mission, potential protocols of all layers were compared and analyzed. Simulations were made based on OPNET. And a suggestion for space communication protocol stacks is proposed.

This dissertation focuses on service scheduling and transshipment problems. The study of service scheduling is motivated by decisions facing service planners, who must inspect and maintain geographically dispersed infrastructure facilities. We study the problem of deciding which operations a service unit must perform at each customer location, given the sequence in which the unit periodically visits these locations. Each customer requires multiple service operations, and each operation has a time-varying completion or penalty cost that depends on the previous service time. The goal is to schedule the service start time for each customer and select the operations to perform so as to minimize the total completion cost. We first discuss how to solve a special case of this problem in which each site is visited only once per service cycle. We formulate this problem as a discrete time indexed network flow problem and prove that it is NP-hard in the ordinary sense. Then, we represent the problem as a multidimensional shortest path problem with path-dependent arc lengths. In this structure, arc costs depend on the total time spent for all customers. The resulting formulation is solvable via algorithms that have pseudo-polynomial run times. Computational results show that the shortest path approach outperformed the general network flow model. We then analyze the general case of this problem, in which each site can be visited more than once and prove that the problem is NP-Hard in the strong sense. We discuss the valid cuts and describe the preprocessor that reduces the problem size. Next, we examine an application to the general case of the problem and develop a fast and effective heuristic procedure that repeatedly applies the shortest path approach to subsequences that do not visit any customer more than once. Computational results for several problem instances show that the proposed heuristic identifies near optimal results very quickly, whereas a general purpose integer-programming solver (CPLEX) is not able to find an optimal solution even after many hours of computational time. Then we focus on techniques such as problem reduction, branching variables, and subdividing problem to smaller problems to get better solution times for the actual problem. Computational results show that these techniques can improve solution times substantially. Finally, we study a transshipment problem, in which the shipments need to be transported from their origin to destination and are subject to the logical and physical transportation network on which they rely. We consider a space-time network that allows one to formulate the problem as a multi-commodity network flow problem with additional side constraints and show the complexity results. We propose alternative models and propose algorithms for lower and upper bound calculations. / text

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Presently, NASA's Space Network (SN) does not have the ability to receive random messages from satellites using the system. Scheduling of the service must be done by the owner of the spacecraft through Goddard Space Flight Center (GSFC). The goal of NASA is to improve the current system so that random messages, that are generated on board the satellite, can be received by the SN. The messages will be requests for service that the satellites control system deems necessary. These messages will then be sent to the owner of the spacecraft where appropriate action and scheduling can take place. This new service is known as the Demand Assignment Multiple Access system (DAMA).

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The National Aeronautics and Space Administration (NASA) Space Network (SN) consists of a Space Segment, composed of the Tracking and Data Relay Satellite (TDRS) fleet, and a Ground Segment that includes the White Sands Ground Terminal (WSGT), Second TDRS Ground Terminal (STGT) and the Guam Remote Ground Terminal (GRGT). Collectively, the SN Ground Segment is commonly referred to as the White Sands Complex (WSC). Traditional methods of latency and performance measurement across the component links of network have relied on the use of simplified test patterns and basic data formats that are often specific to the instruments providing the measurements. These tests do not often correlate to the operational data normally transferred through the network. This paper discusses an alternative approach to performance measurement within the Space Network. By embedding and extracting performance metrics directly within simulated data sets that closely resemble operational traffic, performance measurement can be combined with link verification and validation to provide a single, comprehensive set of test and measurement activities.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / NASA's Space Network (SN) provides both single access (SA) and multiple access (MA) services through a pre-scheduling system. Currently, a user's spacecraft is incapable of receiving service unless prior scheduling occurred with the control center. NASA is interested in efficiently utilizing the time between scheduled services. Thus, a demand assignment multiple access (DAMA) service study was conducted to provide a solution. The DAMA service would allow the user's spacecraft to initiate a service request. The control center could then schedule the next available time slot upon owner approval. In this paper, the basic DAMA service request design and integration is presented.

International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper describes the new Telemetry Processor Hardware (TPH) that Avtec Systems has developed for the Deep Space Network (DSN) Telemetry Processor (TLP) system. Avtec is providing the Telemetry Processor Hardware to RTLogic! for integration into the Telemetry Processor system. The Deep Space Network (DSN) is an international network of antennas that supports interplanetary spacecraft missions for exploration of the solar system and the universe. The Jet Propulsion Laboratory manages the DSN for NASA. The TLP system provides the capability to acquire, process, decode and distribute deep space probe and Earth orbiter telemetry data. The new TLP systems will be deployed at each of the three deep-space communications facilities placed approximately 120 degrees apart around the world: at Goldstone, California; near Madrid, Spain; and near Canberra, Australia. The Telemetry Processor Hardware (TPH) supports both CCSDS and TDM telemetry data formats. The TPH performs the following processing steps: soft-symbol input selection and measurement; convolutional decoding; routing to external decoders; time tagging; frame synchronization; derandomization; and Reed-Solomon decoding. The TPH consists of a VME Viterbi Decoder/MCD III Interface board (VM-7001) and a PCI-mezzanine Frame Synchronizer/Reed-Solomon Decoder (PMC- 6130-J) board. The new Telemetry Processor Hardware is implemented using the latest Field Programmable Gate Array (FPGA) technology to provide the density and speed to meet the current requirements as well as the flexibility to accommodate processing enhancements in the future.

O problema de escalonamento de veículos com múltiplas garagens (MDVSP, do inglês Multi-Depot Vehicle Scheduling Problem) é um problema clássico de logística e transportes. O MDVSP também é a base para a solução de vários problemas correlatos, tais como o problema de escalonamento de veículos em tempo-real e soluções integradas com o escalonamento de veículos, tais como o escalonamento da tripulação e otimização da tabela de horários. Desta forma, aprimorar a solução deste problema pode ser considerado de grande relevância, a qual permitirá resolver grandes instâncias reais de forma eficiente, bem como permitir a solução de problemas correlatos. O objetivo desta dissertação é verificar a aplicabilidade da utilização da rede tempo-espaço e do método de geração de colunas modificado proposto, para a solução deste problema, e de sua variante com frota heterogênea, considerando grandes instâncias. Diversos testes foram realizados utilizando o gerador de instâncias aleatórias com base na distribuição de demandas proposto. Grandes instâncias, envolvendo milhares de viagens (entre 500-10.000) e dezenas de garagens (4-128) são resolvidas em tempos razoáveis. / The multiple-depot vehicle-scheduling problem (MDVSP) is a classic logistic and transportation problem. The MDVSP is also a subproblem for solving various related problems, such as the real time vehicle scheduling problem, disruption management; and integrated problems such as the vehicle and crew scheduling problems. Although several mathematical and solution method have been developed in the literature, large instances (involving thousands of trips and several depots) are still difficult to solve in a reasonable time. The objective of this research work is to verify the applicability of the use of the space-time network towards obtaining good solutions for large instances in short time. Time-space network was suggested by Kliewer et al (2006), and it is positioned with respect to two-dimensional axes, one representing time and the other one space or stations. The arcs represent deadheading movements; and waiting periods in the same station. Solution methods for the MDVS combining time space with integer linear programming solvers and column generation were developed. Extensive testing was carried out using random generated instances, based on demands distribution. Large instances, involving thousands of trips (between 1,000-10,000) and dozen (4-64) depots, are solved in reasonable times.

O problema de escalonamento de veículos com múltiplas garagens (MDVSP, do inglês Multi-Depot Vehicle Scheduling Problem) é um problema clássico de logística e transportes. O MDVSP também é a base para a solução de vários problemas correlatos, tais como o problema de escalonamento de veículos em tempo-real e soluções integradas com o escalonamento de veículos, tais como o escalonamento da tripulação e otimização da tabela de horários. Desta forma, aprimorar a solução deste problema pode ser considerado de grande relevância, a qual permitirá resolver grandes instâncias reais de forma eficiente, bem como permitir a solução de problemas correlatos. O objetivo desta dissertação é verificar a aplicabilidade da utilização da rede tempo-espaço e do método de geração de colunas modificado proposto, para a solução deste problema, e de sua variante com frota heterogênea, considerando grandes instâncias. Diversos testes foram realizados utilizando o gerador de instâncias aleatórias com base na distribuição de demandas proposto. Grandes instâncias, envolvendo milhares de viagens (entre 500-10.000) e dezenas de garagens (4-128) são resolvidas em tempos razoáveis. / The multiple-depot vehicle-scheduling problem (MDVSP) is a classic logistic and transportation problem. The MDVSP is also a subproblem for solving various related problems, such as the real time vehicle scheduling problem, disruption management; and integrated problems such as the vehicle and crew scheduling problems. Although several mathematical and solution method have been developed in the literature, large instances (involving thousands of trips and several depots) are still difficult to solve in a reasonable time. The objective of this research work is to verify the applicability of the use of the space-time network towards obtaining good solutions for large instances in short time. Time-space network was suggested by Kliewer et al (2006), and it is positioned with respect to two-dimensional axes, one representing time and the other one space or stations. The arcs represent deadheading movements; and waiting periods in the same station. Solution methods for the MDVS combining time space with integer linear programming solvers and column generation were developed. Extensive testing was carried out using random generated instances, based on demands distribution. Large instances, involving thousands of trips (between 1,000-10,000) and dozen (4-64) depots, are solved in reasonable times.

O problema de escalonamento de veículos com múltiplas garagens (MDVSP, do inglês Multi-Depot Vehicle Scheduling Problem) é um problema clássico de logística e transportes. O MDVSP também é a base para a solução de vários problemas correlatos, tais como o problema de escalonamento de veículos em tempo-real e soluções integradas com o escalonamento de veículos, tais como o escalonamento da tripulação e otimização da tabela de horários. Desta forma, aprimorar a solução deste problema pode ser considerado de grande relevância, a qual permitirá resolver grandes instâncias reais de forma eficiente, bem como permitir a solução de problemas correlatos. O objetivo desta dissertação é verificar a aplicabilidade da utilização da rede tempo-espaço e do método de geração de colunas modificado proposto, para a solução deste problema, e de sua variante com frota heterogênea, considerando grandes instâncias. Diversos testes foram realizados utilizando o gerador de instâncias aleatórias com base na distribuição de demandas proposto. Grandes instâncias, envolvendo milhares de viagens (entre 500-10.000) e dezenas de garagens (4-128) são resolvidas em tempos razoáveis. / The multiple-depot vehicle-scheduling problem (MDVSP) is a classic logistic and transportation problem. The MDVSP is also a subproblem for solving various related problems, such as the real time vehicle scheduling problem, disruption management; and integrated problems such as the vehicle and crew scheduling problems. Although several mathematical and solution method have been developed in the literature, large instances (involving thousands of trips and several depots) are still difficult to solve in a reasonable time. The objective of this research work is to verify the applicability of the use of the space-time network towards obtaining good solutions for large instances in short time. Time-space network was suggested by Kliewer et al (2006), and it is positioned with respect to two-dimensional axes, one representing time and the other one space or stations. The arcs represent deadheading movements; and waiting periods in the same station. Solution methods for the MDVS combining time space with integer linear programming solvers and column generation were developed. Extensive testing was carried out using random generated instances, based on demands distribution. Large instances, involving thousands of trips (between 1,000-10,000) and dozen (4-64) depots, are solved in reasonable times.