Improved Space Surveillance Network (SSN) Scheduling using Artificial Intelligence Techniques

NASA Astrophysics Data System (ADS)

Stottler, D.

There are close to 20,000 cataloged manmade objects in space, the large majority of which are not active, functioning satellites. These are tracked by phased array and mechanical radars and ground and space-based optical telescopes, collectively known as the Space Surveillance Network (SSN). A better SSN schedule of observations could, using exactly the same legacy sensor resources, improve space catalog accuracy through more complementary tracking, provide better responsiveness to real-time changes, better track small debris in low earth orbit (LEO) through efficient use of applicable sensors, efficiently track deep space (DS) frequent revisit objects, handle increased numbers of objects and new types of sensors, and take advantage of future improved communication and control to globally optimize the SSN schedule. We have developed a scheduling algorithm that takes as input the space catalog and the associated covariance matrices and produces a globally optimized schedule for each sensor site as to what objects to observe and when. This algorithm is able to schedule more observations with the same sensor resources and have those observations be more complementary, in terms of the precision with which each orbit metric is known, to produce a satellite observation schedule that, when executed, minimizes the covariances across the entire space object catalog. If used operationally, the results would be significantly increased accuracy of the space catalog with fewer lost objects with the same set of sensor resources. This approach inherently can also trade-off fewer high priority tasks against more lower-priority tasks, when there is benefit in doing so. Currently the project has completed a prototyping and feasibility study, using open source data on the SSN's sensors, that showed significant reduction in orbit metric covariances. The algorithm techniques and results will be discussed along with future directions for the research.

The JPL Resource Allocation Planning and Scheduling Office (RAPSO) process

NASA Technical Reports Server (NTRS)

Morris, D. G.; Burke, E. S.

2002-01-01

The Jet Propulsion Laboratory's Resource Allocation Planning and Scheduling Office is chartered to divide the limited amount of tracking hours of the Deep Space Network amongst the various missions in as equitable allotment as can be achieved. To best deal with this division of assets and time, an interactive process has evolved that promotes discussion with agreement by consensus between all of the customers that use the Deep Space Network (DSN). Aided by a suite of tools, the task of division of asset time is then performed in three stages of granularity. Using this approach, DSN loads are either forecasted or scheduled throughout a moving 10-year window.

Networks Technology Conference

NASA Technical Reports Server (NTRS)

Tasaki, Keiji K. (Editor)

1993-01-01

The papers included in these proceedings represent the most interesting and current topics being pursued by personnel at GSFC's Networks Division and supporting contractors involved in Space, Ground, and Deep Space Network (DSN) technical work. Although 29 papers are represented in the proceedings, only 12 were presented at the conference because of space and time limitations. The proceedings are organized according to five principal technical areas of interest to the Networks Division: Project Management; Network Operations; Network Control, Scheduling, and Monitoring; Modeling and Simulation; and Telecommunications Engineering.

NASDA knowledge-based network planning system

NASA Technical Reports Server (NTRS)

Yamaya, K.; Fujiwara, M.; Kosugi, S.; Yambe, M.; Ohmori, M.

1993-01-01

One of the SODS (space operation and data system) sub-systems, NP (network planning) was the first expert system used by NASDA (national space development agency of Japan) for tracking and control of satellite. The major responsibilities of the NP system are: first, the allocation of network and satellite control resources and, second, the generation of the network operation plan data (NOP) used in automated control of the stations and control center facilities. Up to now, the first task of network resource scheduling was done by network operators. NP system automatically generates schedules using its knowledge base, which contains information on satellite orbits, station availability, which computer is dedicated to which satellite, and how many stations must be available for a particular satellite pass or a certain time period. The NP system is introduced.

Cash transportation vehicle routing and scheduling under stochastic travel times

NASA Astrophysics Data System (ADS)

Yan, Shangyao; Wang, Sin-Siang; Chang, Yu-Hsuan

2014-03-01

Stochastic disturbances occurring in real-world operations could have a significant influence on the planned routing and scheduling results of cash transportation vehicles. In this study, a time-space network flow technique is utilized to construct a cash transportation vehicle routing and scheduling model incorporating stochastic travel times. In addition, to help security carriers to formulate more flexible routes and schedules, a concept of the similarity of time and space for vehicle routing and scheduling is incorporated into the model. The test results show that the model could be useful for security carriers in actual practice.

Collaborative Scheduling Using JMS in a Mixed Java and .NET Environment

NASA Technical Reports Server (NTRS)

Wang, Yeou-Fang; Wax, Allan; Lam, Ray; Baldwin, John; Borden, Chet

2006-01-01

A viewgraph presentation to demonstrate collaborative scheduling using Java Message Service (JMS) in a mixed Java and .Net environment is given. The topics include: 1) NASA Deep Space Network scheduling; 2) Collaborative scheduling concept; 3) Distributed computing environment; 4) Platform concerns in a distributed environment; 5) Messaging and data synchronization; and 6) The prototype.

Cell transmission model of dynamic assignment for urban rail transit networks.

PubMed

Xu, Guangming; Zhao, Shuo; Shi, Feng; Zhang, Feilian

2017-01-01

For urban rail transit network, the space-time flow distribution can play an important role in evaluating and optimizing the space-time resource allocation. For obtaining the space-time flow distribution without the restriction of schedules, a dynamic assignment problem is proposed based on the concept of continuous transmission. To solve the dynamic assignment problem, the cell transmission model is built for urban rail transit networks. The priority principle, queuing process, capacity constraints and congestion effects are considered in the cell transmission mechanism. Then an efficient method is designed to solve the shortest path for an urban rail network, which decreases the computing cost for solving the cell transmission model. The instantaneous dynamic user optimal state can be reached with the method of successive average. Many evaluation indexes of passenger flow can be generated, to provide effective support for the optimization of train schedules and the capacity evaluation for urban rail transit network. Finally, the model and its potential application are demonstrated via two numerical experiments using a small-scale network and the Beijing Metro network.

In-Space Crew-Collaborative Task Scheduling

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth; Richardson, Lea

2006-01-01

As humans venture farther from Earth for longer durations, it will become essential for those on the journey to have significant control over the scheduling of their own activities as well as the activities of their companion systems and robots. However, the crew will not do all the scheduling; timelines will be the result of collaboration with ground personnel. Emerging technologies such as in-space message buses, delay-tolerant networks, and in-space internet will be the carriers on which the collaboration rides. Advances in scheduling technology, in the areas of task modeling, scheduling engines, and user interfaces will allow the crew to become virtual scheduling experts. New concepts of operations for producing the timeline will allow the crew and the ground support to collaborate while providing safeguards to ensure that the mission will be effectively accomplished without endangering the systems or personnel.

The deep space network, volume 6

NASA Technical Reports Server (NTRS)

1971-01-01

Progress on Deep Space Network (DSN) supporting research and technology is presented, together with advanced development and engineering, implementation, and DSN operations of flight projects. The DSN is described. Interplanetary and planetary flight projects and radio science experiments are discussed. Tracking and navigational accuracy analysis, communications systems and elements research, and supporting research are considered. Development of the ground communications and deep space instrumentation facilities is also presented. Network allocation schedules and angle tracking and test development are included.

Learning Search Control Knowledge for Deep Space Network Scheduling

NASA Technical Reports Server (NTRS)

Gratch, Jonathan; Chien, Steve; DeJong, Gerald

1993-01-01

While the general class of most scheduling problems is NP-hard in worst-case complexity, in practice, for specific distributions of problems and constraints, domain-specific solutions have been shown to perform in much better than exponential time.

In-Space Crew-Collaborative Task Scheduling

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth; Richardson, Lea

2006-01-01

As humans venture farther from earth for longer durations, it will become essential for those on the journey to have significant control over the scheduling of their own activities as well as the activities of their companion systems and robots. However, there are many reasons why the crew will not do all the scheduling; timelines will be the result of collaboration with ground personnel. Emerging technologies such as in-space message buses, delay-tolerant networks, and in-space internet will be the carriers on which the collaboration rides. Advances in scheduling technology, in the areas of task modeling, scheduling engines, and user interfaces will allow the crew to become virtual scheduling experts. New concepts of operations for producing the timeline will allow the crew and the ground support to collaborate while providing safeguards to ensure that the mission will be effectively accomplished without endangering the systems or personnel.

Virtual Mission Operations of Remote Sensors With Rapid Access To and From Space

NASA Technical Reports Server (NTRS)

Ivancic, William D.; Stewart, Dave; Walke, Jon; Dikeman, Larry; Sage, Steven; Miller, Eric; Northam, James; Jackson, Chris; Taylor, John; Lynch, Scott;

Sensor-scheduling simulation of disparate sensors for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Hobson, T.; Clarkson, I.

2011-09-01

The art and science of space situational awareness (SSA) has been practised and developed from the time of Sputnik. However, recent developments, such as the accelerating pace of satellite launch, the proliferation of launch capable agencies, both commercial and sovereign, and recent well-publicised collisions involving man-made space objects, has further magnified the importance of timely and accurate SSA. The United States Strategic Command (USSTRATCOM) operates the Space Surveillance Network (SSN), a global network of sensors tasked with maintaining SSA. The rapidly increasing number of resident space objects will require commensurate improvements in the SSN. Sensors are scarce resources that must be scheduled judiciously to obtain measurements of maximum utility. Improvements in sensor scheduling and fusion, can serve to reduce the number of additional sensors that may be required. Recently, Hill et al. [1] have proposed and developed a simulation environment named TASMAN (Tasking Autonomous Sensors in a Multiple Application Network) to enable testing of alternative scheduling strategies within a simulated multi-sensor, multi-target environment. TASMAN simulates a high-fidelity, hardware-in-the-loop system by running multiple machines with different roles in parallel. At present, TASMAN is limited to simulations involving electro-optic sensors. Its high fidelity is at once a feature and a limitation, since supercomputing is required to run simulations of appreciable scale. In this paper, we describe an alternative, modular and scalable SSA simulation system that can extend the work of Hill et al with reduced complexity, albeit also with reduced fidelity. The tool has been developed in MATLAB and therefore can be run on a very wide range of computing platforms. It can also make use of MATLAB’s parallel processing capabilities to obtain considerable speed-up. The speed and flexibility so obtained can be used to quickly test scheduling algorithms even with a relatively large number of space objects. We further describe an application of the tool by exploring how the relative mixture of electro-optical and radar sensors can impact the scheduling, fusion and achievable accuracy of an SSA system. By varying the mixture of sensor types, we are able to characterise the main advantages and disadvantages of each configuration.

Space Network Control Conference on Resource Allocation Concepts and Approaches

NASA Technical Reports Server (NTRS)

Moe, Karen L. (Editor)

1991-01-01

The results are presented of the Space Network Control (SNC) Conference. In the late 1990s, when the Advanced Tracking and Data Relay Satellite System is operational, Space Network communication services will be supported and controlled by the SNC. The goals of the conference were to survey existing resource allocation concepts and approaches, to identify solutions applicable to the Space Network, and to identify avenues of study in support of the SNC development. The conference was divided into three sessions: (1) Concepts for Space Network Allocation; (2) SNC and User Payload Operations Control Center (POCC) Human-Computer Interface Concepts; and (3) Resource Allocation Tools, Technology, and Algorithms. Key recommendations addressed approaches to achieving higher levels of automation in the scheduling process.

Optimal Scheduling and Fair Service Policy for STDMA in Underwater Networks with Acoustic Communications

PubMed Central

2018-01-01

In this work, a multi-hop string network with a single sink node is analyzed. A periodic optimal scheduling for TDMA operation that considers the characteristic long propagation delay of the underwater acoustic channel is presented. This planning of transmissions is obtained with the help of a new geometrical method based on a 2D lattice in the space-time domain. In order to evaluate the performance of this optimal scheduling, two service policies have been compared: FIFO and Round-Robin. Simulation results, including achievable throughput, packet delay, and queue length, are shown. The network fairness has also been quantified with the Gini index. PMID:29462966

Utilizing Novel Non-traditional Sensor Tasking Approaches to Enhance the Space Situational Awareness Picture Maintained by the Space Surveillance Network

NASA Astrophysics Data System (ADS)

Herz, A.; Herz, E.; Center, K.; George, P.; Axelrad, P.; Mutschler, S.; Jones, B.

2016-09-01

The Space Surveillance Network (SSN) is tasked with the increasingly difficult mission of detecting, tracking, cataloging and identifying artificial objects orbiting the Earth, including active and inactive satellites, spent rocket bodies, and fragmented debris. Much of the architecture and operations of the SSN are limited and outdated. Efforts are underway to modernize some elements of the systems. Even so, the ability to maintain the best current Space Situational Awareness (SSA) picture and identify emerging events in a timely fashion could be significantly improved by leveraging non-traditional sensor sites. Orbit Logic, the University of Colorado and the University of Texas at Austin are developing an innovative architecture and operations concept to coordinate the tasking and observation information processing of non - traditional assets based on information-theoretic approaches. These confirmed tasking schedules and the resulting data can then be used to "inform" the SSN tasking process. The 'Heimdall Web' system is comprised of core tasking optimization components and accompanying Web interfaces within a secure, split architecture that will for the first time allow non-traditional sensors to support SSA and improve SSN tasking. Heimdall Web application components appropriately score/prioritize space catalog objects based on covariance, priority, observability, expected information gain, and probability of detect - then coordinate an efficient sensor observation schedule for non-SSN sensors contributing to the overall SSA picture maintained by the Joint Space Operations Center (JSpOC). The Heimdall Web Ops concept supports sensor participation levels of "Scheduled", "Tasked" and "Contributing". Scheduled and Tasked sensors are provided optimized observation schedules or object tracking lists from central algorithms, while Contributing sensors review and select from a list of "desired track objects". All sensors are "Web Enabled" for tasking and feedback, supplying observation schedules, confirmed observations and related data back to Heimdall Web to complete the feedback loop for the next scheduling iteration.

Collaborative Resource Allocation

NASA Technical Reports Server (NTRS)

Wang, Yeou-Fang; Wax, Allan; Lam, Raymond; Baldwin, John; Borden, Chester

2007-01-01

Collaborative Resource Allocation Networking Environment (CRANE) Version 0.5 is a prototype created to prove the newest concept of using a distributed environment to schedule Deep Space Network (DSN) antenna times in a collaborative fashion. This program is for all space-flight and terrestrial science project users and DSN schedulers to perform scheduling activities and conflict resolution, both synchronously and asynchronously. Project schedulers can, for the first time, participate directly in scheduling their tracking times into the official DSN schedule, and negotiate directly with other projects in an integrated scheduling system. A master schedule covers long-range, mid-range, near-real-time, and real-time scheduling time frames all in one, rather than the current method of separate functions that are supported by different processes and tools. CRANE also provides private workspaces (both dynamic and static), data sharing, scenario management, user control, rapid messaging (based on Java Message Service), data/time synchronization, workflow management, notification (including emails), conflict checking, and a linkage to a schedule generation engine. The data structure with corresponding database design combines object trees with multiple associated mortal instances and relational database to provide unprecedented traceability and simplify the existing DSN XML schedule representation. These technologies are used to provide traceability, schedule negotiation, conflict resolution, and load forecasting from real-time operations to long-range loading analysis up to 20 years in the future. CRANE includes a database, a stored procedure layer, an agent-based middle tier, a Web service wrapper, a Windows Integrated Analysis Environment (IAE), a Java application, and a Web page interface.

Columbia's first flight shakes down space transportation system

NASA Technical Reports Server (NTRS)

Garrett, D.; Young, D.; White, T.

1981-01-01

The first space shuttle mission is described. Topics include launch preparations, flight profile, trajectory, and landing operations. The spaceflight tracking and data network is discussed and the photography and television schedules are included.

Analysis on Tracking Schedule and Measurements Characteristics for the Spacecraft on the Phase of Lunar Transfer and Capture

NASA Astrophysics Data System (ADS)

Song, Young-Joo; Choi, Su-Jin; Ahn, Sang-il; Sim, Eun-Sup

2014-03-01

In this work, the preliminary analysis on both the tracking schedule and measurements characteristics for the spacecraft on the phase of lunar transfer and capture is performed. To analyze both the tracking schedule and measurements characteristics, lunar transfer and capture phases¡¯ optimized trajectories are directly adapted from former research, and eleven ground tracking facilities (three Deep Space Network sties, seven Near Earth Network sites, one Daejeon site) are assumed to support the mission. Under these conceptual mission scenarios, detailed tracking schedules and expected measurement characteristics during critical maneuvers (Trans Lunar Injection, Lunar Orbit Insertion and Apoapsis Adjustment Maneuver), especially for the Deajeon station, are successfully analyzed. The orders of predicted measurements' variances during lunar capture phase according to critical maneuvers are found to be within the order of mm/s for the range and micro-deg/s for the angular measurements rates which are in good agreement with the recommended values of typical measurement modeling accuracies for Deep Space Networks. Although preliminary navigation accuracy guidelines are provided through this work, it is expected to give more practical insights into preparing the Korea's future lunar mission, especially for developing flight dynamics subsystem.

Deep Space Network Scheduling Using Evolutionary Computational Methods

NASA Technical Reports Server (NTRS)

Guillaume, Alexandre; Lee, Seugnwon; Wang, Yeou-Fang; Terrile, Richard J.

2007-01-01

The paper presents the specific approach taken to formulate the problem in terms of gene encoding, fitness function, and genetic operations. The genome is encoded such that a subset of the scheduling constraints is automatically satisfied. Several fitness functions are formulated to emphasize different aspects of the scheduling problem. The optimal solutions of the different fitness functions demonstrate the trade-off of the scheduling problem and provide insight into a conflict resolution process.

Automated Platform Management System Scheduling

NASA Technical Reports Server (NTRS)

Hull, Larry G.

1990-01-01

The Platform Management System was established to coordinate the operation of platform systems and instruments. The management functions are split between ground and space components. Since platforms are to be out of contact with the ground more than the manned base, the on-board functions are required to be more autonomous than those of the manned base. Under this concept, automated replanning and rescheduling, including on-board real-time schedule maintenance and schedule repair, are required to effectively and efficiently meet Space Station Freedom mission goals. In a FY88 study, we developed several promising alternatives for automated platform planning and scheduling. We recommended both a specific alternative and a phased approach to automated platform resource scheduling. Our recommended alternative was based upon use of exactly the same scheduling engine in both ground and space components of the platform management system. Our phased approach recommendation was based upon evolutionary development of the platform. In the past year, we developed platform scheduler requirements and implemented a rapid prototype of a baseline platform scheduler. Presently we are rehosting this platform scheduler rapid prototype and integrating the scheduler prototype into two Goddard Space Flight Center testbeds, as the ground scheduler in the Scheduling Concepts, Architectures, and Networks Testbed and as the on-board scheduler in the Platform Management System Testbed. Using these testbeds, we will investigate rescheduling issues, evaluate operational performance and enhance the platform scheduler prototype to demonstrate our evolutionary approach to automated platform scheduling. The work described in this paper was performed prior to Space Station Freedom rephasing, transfer of platform responsibility to Code E, and other recently discussed changes. We neither speculate on these changes nor attempt to predict the impact of the final decisions. As a consequence some of our work and results may be outdated when this paper is published.

Integrated resource scheduling in a distributed scheduling environment

NASA Technical Reports Server (NTRS)

Zoch, David; Hall, Gardiner

1988-01-01

The Space Station era presents a highly-complex multi-mission planning and scheduling environment exercised over a highly distributed system. In order to automate the scheduling process, customers require a mechanism for communicating their scheduling requirements to NASA. A request language that a remotely-located customer can use to specify his scheduling requirements to a NASA scheduler, thus automating the customer-scheduler interface, is described. This notation, Flexible Envelope-Request Notation (FERN), allows the user to completely specify his scheduling requirements such as resource usage, temporal constraints, and scheduling preferences and options. The FERN also contains mechanisms for representing schedule and resource availability information, which are used in the inter-scheduler inconsistency resolution process. Additionally, a scheduler is described that can accept these requests, process them, generate schedules, and return schedule and resource availability information to the requester. The Request-Oriented Scheduling Engine (ROSE) was designed to function either as an independent scheduler or as a scheduling element in a network of schedulers. When used in a network of schedulers, each ROSE communicates schedule and resource usage information to other schedulers via the FERN notation, enabling inconsistencies to be resolved between schedulers. Individual ROSE schedules are created by viewing the problem as a constraint satisfaction problem with a heuristically guided search strategy.

Request-Driven Schedule Automation for the Deep Space Network

NASA Technical Reports Server (NTRS)

Johnston, Mark D.; Tran, Daniel; Arroyo, Belinda; Call, Jared; Mercado, Marisol

2010-01-01

The DSN Scheduling Engine (DSE) has been developed to increase the level of automated scheduling support available to users of NASA s Deep Space Network (DSN). We have adopted a request-driven approach to DSN scheduling, in contrast to the activity-oriented approach used up to now. Scheduling requests allow users to declaratively specify patterns and conditions on their DSN service allocations, including timing, resource requirements, gaps, overlaps, time linkages among services, repetition, priorities, and a wide range of additional factors and preferences. The DSE incorporates a model of the key constraints and preferences of the DSN scheduling domain, along with algorithms to expand scheduling requests into valid resource allocations, to resolve schedule conflicts, and to repair unsatisfied requests. We use time-bounded systematic search with constraint relaxation to return nearby solutions if exact ones cannot be found, where the relaxation options and order are under user control. To explore the usability aspects of our approach we have developed a graphical user interface incorporating some crucial features to make it easier to work with complex scheduling requests. Among these are: progressive revelation of relevant detail, immediate propagation and visual feedback from a user s decisions, and a meeting calendar metaphor for repeated patterns of requests. Even as a prototype, the DSE has been deployed and adopted as the initial step in building the operational DSN schedule, thus representing an important initial validation of our overall approach. The DSE is a core element of the DSN Service Scheduling Software (S(sup 3)), a web-based collaborative scheduling system now under development for deployment to all DSN users.

The Automated Conflict Resolution System (ACRS)

NASA Technical Reports Server (NTRS)

Kaplan, Ted; Musliner, Andrew; Wampler, David

1993-01-01

The Automated Conflict Resolution System (ACRS) is a mission-current scheduling aid that predicts periods of mutual interference when two or more orbiting spacecraft are scheduled to communicate with the same Tracking and Data Relay Satellite (TDRS) at the same time. The mutual interference predicted has the potential to degrade or prevent communications. Thus the ACRS system is a useful tool for aiding in the scheduling of Space Network (SN) communications.

The Automated Conflict Resolution System (ACRS)

NASA Astrophysics Data System (ADS)

Kaplan, Ted; Musliner, Andrew; Wampler, David

1993-11-01

The Automated Conflict Resolution System (ACRS) is a mission-current scheduling aid that predicts periods of mutual interference when two or more orbiting spacecraft are scheduled to communicate with the same Tracking and Data Relay Satellite (TDRS) at the same time. The mutual interference predicted has the potential to degrade or prevent communications. Thus the ACRS system is a useful tool for aiding in the scheduling of Space Network (SN) communications.

On-Line Data Reconstruction in Redundant Disk Arrays.

DTIC Science & Technology

1994-05-01

each sale, - file servers that support a large number of clients with differing work schedules , and * automated teller networks in banking systems...24KB Head scheduling : FIFO User data layout: Sequential in address space of array Disk spindles: Synchronized Table 2.2: Default array parameters for...package and a set of scheduling and queueing routines. 2.3.3. Default workload This dissertation reports on many performance evaluations. In order to

Runtime Performance and Virtual Network Control Alternatives in VM-Based High-Fidelity Network Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoginath, Srikanth B; Perumalla, Kalyan S; Henz, Brian J

2012-01-01

In prior work (Yoginath and Perumalla, 2011; Yoginath, Perumalla and Henz, 2012), the motivation, challenges and issues were articulated in favor of virtual time ordering of Virtual Machines (VMs) in network simulations hosted on multi-core machines. Two major components in the overall virtualization challenge are (1) virtual timeline establishment and scheduling of VMs, and (2) virtualization of inter-VM communication. Here, we extend prior work by presenting scaling results for the first component, with experiment results on up to 128 VMs scheduled in virtual time order on a single 12-core host. We also explore the solution space of design alternatives formore » the second component, and present performance results from a multi-threaded, multi-queue implementation of inter-VM network control for synchronized execution with VM scheduling, incorporated in our NetWarp simulation system.« less

DSN Resource Scheduling

NASA Technical Reports Server (NTRS)

Wang, Yeou-Fang; Baldwin, John

2007-01-01

TIGRAS is client-side software, which provides tracking-station equipment planning, allocation, and scheduling services to the DSMS (Deep Space Mission System). TIGRAS provides functions for schedulers to coordinate the DSN (Deep Space Network) antenna usage time and to resolve the resource usage conflicts among tracking passes, antenna calibrations, maintenance, and system testing activities. TIGRAS provides a fully integrated multi-pane graphical user interface for all scheduling operations. This is a great improvement over the legacy VAX VMS command line user interface. TIGRAS has the capability to handle all DSN resource scheduling aspects from long-range to real time. TIGRAS assists NASA mission operations for DSN tracking of station equipment resource request processes from long-range load forecasts (ten years or longer), to midrange, short-range, and real-time (less than one week) emergency tracking plan changes. TIGRAS can be operated by NASA mission operations worldwide to make schedule requests for the DSN station equipment.

Remote Collaboration on Task Scheduling for Humans at Mars

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth; Richardson, Lea

2006-01-01

As humans venture farther from Earth for longer durations, it will become essential for those on the journey to have significant control over the scheduling of their own activities as well as the activities of their companion systems and robots. However, the crew will not do all the scheduling; timelines will be the result of collaboration with ground personnel. Emerging technologies such as in-space message buses, delay-tolerant networks, and in-space internet will be the carriers on which the collaboration rides. Advances in scheduling technology, in the areas of task modeling, scheduling engines, and user interfaces will allow the crew to become virtual scheduling experts. New concepts of operations for producing the timeline will allow the crew and the ground support to collaborate while providing safeguards to ensure that the mission will be effectively accomplished without endangering the systems or personnel.

High performance techniques for space mission scheduling

NASA Technical Reports Server (NTRS)

Smith, Stephen F.

1994-01-01

In this paper, we summarize current research at Carnegie Mellon University aimed at development of high performance techniques and tools for space mission scheduling. Similar to prior research in opportunistic scheduling, our approach assumes the use of dynamic analysis of problem constraints as a basis for heuristic focusing of problem solving search. This methodology, however, is grounded in representational assumptions more akin to those adopted in recent temporal planning research, and in a problem solving framework which similarly emphasizes constraint posting in an explicitly maintained solution constraint network. These more general representational assumptions are necessitated by the predominance of state-dependent constraints in space mission planning domains, and the consequent need to integrate resource allocation and plan synthesis processes. First, we review the space mission problems we have considered to date and indicate the results obtained in these application domains. Next, we summarize recent work in constraint posting scheduling procedures, which offer the promise of better future solutions to this class of problems.

Mixed Integer Programming and Heuristic Scheduling for Space Communication

NASA Technical Reports Server (NTRS)

Lee, Charles H.; Cheung, Kar-Ming

2013-01-01

Optimal planning and scheduling for a communication network was created where the nodes within the network are communicating at the highest possible rates while meeting the mission requirements and operational constraints. The planning and scheduling problem was formulated in the framework of Mixed Integer Programming (MIP) to introduce a special penalty function to convert the MIP problem into a continuous optimization problem, and to solve the constrained optimization problem using heuristic optimization. The communication network consists of space and ground assets with the link dynamics between any two assets varying with respect to time, distance, and telecom configurations. One asset could be communicating with another at very high data rates at one time, and at other times, communication is impossible, as the asset could be inaccessible from the network due to planetary occultation. Based on the network's geometric dynamics and link capabilities, the start time, end time, and link configuration of each view period are selected to maximize the communication efficiency within the network. Mathematical formulations for the constrained mixed integer optimization problem were derived, and efficient analytical and numerical techniques were developed to find the optimal solution. By setting up the problem using MIP, the search space for the optimization problem is reduced significantly, thereby speeding up the solution process. The ratio of the dimension of the traditional method over the proposed formulation is approximately an order N (single) to 2*N (arraying), where N is the number of receiving antennas of a node. By introducing a special penalty function, the MIP problem with non-differentiable cost function and nonlinear constraints can be converted into a continuous variable problem, whose solution is possible.

Genetic algorithms applied to the scheduling of the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Sponsler, Jeffrey L.

1989-01-01

A prototype system employing a genetic algorithm (GA) has been developed to support the scheduling of the Hubble Space Telescope. A non-standard knowledge structure is used and appropriate genetic operators have been created. Several different crossover styles (random point selection, evolving points, and smart point selection) are tested and the best GA is compared with a neural network (NN) based optimizer. The smart crossover operator produces the best results and the GA system is able to evolve complete schedules using it. The GA is not as time-efficient as the NN system and the NN solutions tend to be better.

The R-Shell approach - Using scheduling agents in complex distributed real-time systems

NASA Technical Reports Server (NTRS)

Natarajan, Swaminathan; Zhao, Wei; Goforth, Andre

1993-01-01

Large, complex real-time systems such as space and avionics systems are extremely demanding in their scheduling requirements. The current OS design approaches are quite limited in the capabilities they provide for task scheduling. Typically, they simply implement a particular uniprocessor scheduling strategy and do not provide any special support for network scheduling, overload handling, fault tolerance, distributed processing, etc. Our design of the R-Shell real-time environment fcilitates the implementation of a variety of sophisticated but efficient scheduling strategies, including incorporation of all these capabilities. This is accomplished by the use of scheduling agents which reside in the application run-time environment and are responsible for coordinating the scheduling of the application.

Collaborative Scheduling Using JMS in a Mixed Java and .NET Environment

NASA Technical Reports Server (NTRS)

Wang, Yeou-Fang; Wax, Allan; Lam, Ray; Baldwin, John; Borden, Chet

2006-01-01

A collaborative framework/environment was proto-typed to prove the feasibility of scheduling space flight missions on NASA's Deep Space Network (DSN) in a distributed fashion. In this environment, effective collaboration relies on efficient communications among all flight mission and DSN scheduling users. There-fore, messaging becomes critical to timely event notification and data synchronization. In the prototype, a rapid messaging system using Java Message Service (JMS) in a mixed Java and .NET environment is established. This scheme allows both Java and .NET applications to communicate with each other for data synchronization and schedule negotiation. The JMS approach we used is based on a centralized messaging scheme. With proper use of a high speed messaging system, all users in this collaborative framework can communicate with each other to generate a schedule collaboratively to meet DSN and projects tracking needs.

Space-based Networking Technology Developments in the Interplanetary Network Directorate Information Technology Program

NASA Technical Reports Server (NTRS)

Clare, Loren; Clement, B.; Gao, J.; Hutcherson, J.; Jennings, E.

2006-01-01

Described recent development of communications protocols, services, and associated tools targeted to reduce risk, reduce cost and increase efficiency of IND infrastructure and supported mission operations. Space-based networking technologies developed were: a) Provide differentiated quality of service (QoS) that will give precedence to traffic that users have selected as having the greatest importance and/or time-criticality; b) Improve the total value of information to users through the use of QoS prioritization techniques; c) Increase operational flexibility and improve command-response turnaround; d) Enable new class of networked and collaborative science missions; e) Simplify applications interfaces to communications services; and f) Reduce risk and cost from a common object model and automated scheduling and communications protocols. Technologies are described in three general areas: communications scheduling, middleware, and protocols. Additionally developed simulation environment, which provides comprehensive, quantitative understanding of the technologies performance within overall, evolving architecture, as well as ability to refine & optimize specific components.

Building a Solar System Internet

NASA Technical Reports Server (NTRS)

Clark, Gilbert J.

2018-01-01

This presentation is expected to be given during the scheduled Communications Technology and Development discussion in the University Student Design Challenge (2). It is an introduction to various challenges inherent to the construction of networks in space. The presentation also includes both an overview of networking in general, as well as approaches taken to the construction of delay- and disruption- tolerant networks.

Message Mode Operations for Spacecraft: A Proposal for Operating Spacecraft During Cruise and Mitigating the Network Loading Crunch

NASA Technical Reports Server (NTRS)

Greenberg, Ed; MacMedan, Marv; Kazz, Greg; Kallemeyn, Pieter

2000-01-01

The NASA Deep Space Network (DSN) is a world-class spacecraft tracking facility with stations located in Spain, Australia and USA, servicing Deep Space Missions of many space agencies. The current system of scheduling spacecraft during cruise for multiple 8 hour tracking sessions per week currently leads to an overcommitted DSN. Studies indicate that future projected mission demands upon the Network will only make the loading problem worse. Therefore, a more efficient scheduling of DSN resources is necessary in order to support the additional network loading envisioned in the next few years: The number of missions is projected to increase from 25 in 1998 to 34 by 2001. In fact given the challenge of the NASA administrator, Dan Goldin, of launching 12 spacecraft per year, the DSN would be tracking approximately 90 spacecraft by 2010. Currently a large amount of antenna time and network resources are subscribed by a project in order to have their mission supported during the cruise phase. The recently completed Mars Pathfinder mission was tracked 3 times a week (8 hours/day) during the majority of its cruise to Mars. This paper proposes an innovative approach called Message Mode Operations (MMO) for mitigating the Network loading problem while continuing to meet the tracking, reporting, time management, and scheduling requirements of these missions during Cruise while occupying very short tracking times. MMO satisfies these requirements by providing the following services: Spacecraft Health and Welfare Monitoring Service Command Delivery Service Adaptive Spacecraft Scheduling Service Orbit Determination Service Time Calibration Service Utilizing more efficient engineering telemetry summarization and filtering techniques on-board the spacecraft and collapsing the navigation requirements for Doppler and Range into shorter tracks, we believe spacecraft can be adequately serviced using short 10 to 30 minute tracking sessions. This claim assumes that certain changes would have to he made in the way the Network traditionally services missions in Cruise. Furthermore, limiting spacecraft to short sessions will free up larger blocks of time in the tracking schedule to help accommodate future tracking demands soon to be placed upon the Network. This paper describes the key characteristics and benefits of MMO, the operational scenarios for its use, the required changes to the ground system in order to make this approach feasible and the results of two simulations: 1) to determine the effects of MMO on projected mission loading on the DSN and, 2) to determine the effect MMO has on spacecraft orbit determination.

The 1991 research and technology report, Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Soffen, Gerald (Editor); Ottenstein, Howard (Editor); Montgomery, Harry (Editor); Truszkowski, Walter (Editor); Frost, Kenneth (Editor); Sullivan, Walter (Editor); Boyle, Charles (Editor)

1991-01-01

The 1991 Research and Technology Report for Goddard Space Flight Center is presented. Research covered areas such as (1) earth sciences including upper atmosphere, lower atmosphere, oceans, hydrology, and global studies; (2) space sciences including solar studies, planetary studies, Astro-1, gamma ray investigations, and astrophysics; (3) flight projects; (4) engineering including robotics, mechanical engineering, electronics, imaging and optics, thermal and cryogenic studies, and balloons; and (5) ground systems, networks, and communications including data and networks, TDRSS, mission planning and scheduling, and software development and test.

Spike: Artificial intelligence scheduling for Hubble space telescope

NASA Technical Reports Server (NTRS)

Johnston, Mark; Miller, Glenn; Sponsler, Jeff; Vick, Shon; Jackson, Robert

1990-01-01

Efficient utilization of spacecraft resources is essential, but the accompanying scheduling problems are often computationally intractable and are difficult to approximate because of the presence of numerous interacting constraints. Artificial intelligence techniques were applied to the scheduling of the NASA/ESA Hubble Space Telescope (HST). This presents a particularly challenging problem since a yearlong observing program can contain some tens of thousands of exposures which are subject to a large number of scientific, operational, spacecraft, and environmental constraints. New techniques were developed for machine reasoning about scheduling constraints and goals, especially in cases where uncertainty is an important scheduling consideration and where resolving conflicts among conflicting preferences is essential. These technique were utilized in a set of workstation based scheduling tools (Spike) for HST. Graphical displays of activities, constraints, and schedules are an important feature of the system. High level scheduling strategies using both rule based and neural network approaches were developed. While the specific constraints implemented are those most relevant to HST, the framework developed is far more general and could easily handle other kinds of scheduling problems. The concept and implementation of the Spike system are described along with some experiments in adapting Spike to other spacecraft scheduling domains.

A Service Portal for the Integrated SCaN Network

NASA Technical Reports Server (NTRS)

Marx, Sarah R.

2012-01-01

The Space Communication and Navigation (SCaN) program office owns the assets and services provided by the Deep Space Network (DSN), Near Earth Network (NEN), and Space Network (SN). At present, these individual networks are operated by different NASA centers--JPL for DSN--and Goddard Space Flight Center (GSFC) for NEN and SN--with separate commitments offices for each center. In the near future, SCaN's program office would like to deploy an integrated service portal which would merge the two commitments offices with the goal of easing the task of user planning for space missions requiring services of two or more of these networks. Following interviews with subject matter experts in this field, use cases were created to include the services and functionality mission users would like to see in this new integrated service portal. These use cases provide a guideline for a mock-up of the design of the user interface for the portal. The benefit of this work will ease the time required and streamline/standardize the process for planning and scheduling SCAN's services for future space missions.

Research of the key technology in satellite communication networks

NASA Astrophysics Data System (ADS)

Zeng, Yuan

2018-02-01

According to the prediction, in the next 10 years the wireless data traffic will be increased by 500-1000 times. Not only the wireless data traffic will be increased exponentially, and the demand for diversified traffic will be increased. Higher requirements for future mobile wireless communication system had brought huge market space for satellite communication system. At the same time, the space information networks had been greatly developed with the depth of human exploration of space activities, the development of space application, the expansion of military and civilian application. The core of spatial information networks is the satellite communication. The dissertation presented the communication system architecture, the communication protocol, the routing strategy, switch scheduling algorithm and the handoff strategy based on the satellite communication system. We built the simulation platform of the LEO satellites networks and simulated the key technology using OPNET.

Need for a network of observatories for space debris dynamical and physical characterization

NASA Astrophysics Data System (ADS)

Piergentili, Fabrizio; Santoni, Fabio; Castronuovo, Marco; Portelli, Claudio; Cardona, Tommaso; Arena, Lorenzo; Sciré, Gioacchino; Seitzer, Patrick

2016-01-01

Space debris represents a major concern for space missions since the risk of impact with uncontrolled objects has increased dramatically in recent years. Passive and active mitigation countermeasures are currently under consideration but, at the base of any of such corrective actions is the space debris continuous monitoring through ground based surveillance systems.At the present, many space agencies have the capability to get optical measurements of space orbiting objects mainly relaying on single observatories. The recent research in the field of space debris, demonstrated how it is possible to increase the effectiveness of optical measurements exploitation by using joint observations of the same target from different sites.The University of Rome "La Sapienza", in collaboration with Italian Space Agency (ASI), is developing a scientific network of observatories dedicated to Space Debris deployed in Italy (S5Scope at Rome and SPADE at Matera) and in Kenya at the Broglio Space Center in Malindi (EQUO). ASI founded a program dedicated to space debris, in order to spread the Italian capability to deal with different aspects of this issue. In this framework, the University of Rome is in charge of coordinating the observatories network both in the operation scheduling and in the data analysis. This work describes the features of the observatories dedicated to space debris observation, highlighting their capabilities and detailing their instrumentation. Moreover, the main features of the scheduler under development, devoted to harmonizing the operations of the network, will be shown. This is a new system, which will autonomously coordinate the observations, aiming to optimize results in terms of number of followed targets, amount of time dedicated to survey, accuracy of orbit determination and feasibility of attitude determination through photometric data.Thus, the authors will describe the techniques developed and applied (i) to implement the multi-site orbit determination and (ii) to solve the attitude motion of uncontrolled orbiting objects by exploiting photometric quasi-simultaneous measurements.

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, workers check over the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

NASA Image and Video Library

2004-02-03

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, workers check over the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

The 1992 Goddard Conference on Space Applications of Artificial Intelligence

NASA Technical Reports Server (NTRS)

Rash, James L. (Editor)

1992-01-01

The purpose of this conference is to provide a forum in which current research and development directed at space applications of artificial intelligence can be presented and discussed. The papers fall into the following areas: planning and scheduling, control, fault monitoring/diagnosis and recovery, information management, tools, neural networks, and miscellaneous applications.

Evolutionary space platform concept study. Volume 3: Programmatics for manned space platform concepts

NASA Technical Reports Server (NTRS)

1982-01-01

The programmatic data for the reference concept of the Manned Space Platform is presented. Details regarding work breakdown structure (WBS) and dictionary, the facilities and equipment required to produce the modules, the project schedule and logic diagram, a preliminary assessment of environmental impacts and details regarding the estimated costs for the reference concept are included. The proposed WBS which was developed to provide summary and system level segregation of the nonrecurring and recurring portions of the Manned Space Platform project is also included. The accompanying dictionary outlines the function and activities contained within each WBS element. The facility and equipment required to produce the various modules is discussed. Generally, required equipment is within the existing state of the art although the size of some of the items to be manufactured is a consideration. A preliminary manufacturing flow was also provided. The project schedules presented consist of the Master Project Summary Schedule, the Master Project Phasing Chart and the Logic Network.

An extended abstract: A heuristic repair method for constraint-satisfaction and scheduling problems

NASA Technical Reports Server (NTRS)

Minton, Steven; Johnston, Mark D.; Philips, Andrew B.; Laird, Philip

1992-01-01

The work described in this paper was inspired by a surprisingly effective neural network developed for scheduling astronomical observations on the Hubble Space Telescope. Our heuristic constraint satisfaction problem (CSP) method was distilled from an analysis of the network. In the process of carrying out the analysis, we discovered that the effectiveness of the network has little to do with its connectionist implementation. Furthermore, the ideas employed in the network can be implemented very efficiently within a symbolic CSP framework. The symbolic implementation is extremely simple. It also has the advantage that several different search strategies can be employed, although we have found that hill-climbing methods are particularly well-suited for the applications that we have investigated. We begin the paper with a brief review of the neural network. Following this, we describe our symbolic method for heuristic repair.

DSN Scheduling Engine

NASA Technical Reports Server (NTRS)

Clement, Bradley; Johnston, Mark; Wax, Allan; Chouinard, Caroline

2008-01-01

The DSN (Deep Space Network) Scheduling Engine targets all space missions that use DSN services. It allows clients to issue scheduling, conflict identification, conflict resolution, and status requests in XML over a Java Message Service interface. The scheduling requests may include new requirements that represent a set of tracks to be scheduled under some constraints. This program uses a heuristic local search to schedule a variety of schedule requirements, and is being infused into the Service Scheduling Assembly, a mixed-initiative scheduling application. The engine resolves conflicting schedules of resource allocation according to a range of existing and possible requirement specifications, including optional antennas; start of track and track duration ranges; periodic tracks; locks on track start, duration, and allocated antenna; MSPA (multiple spacecraft per aperture); arraying/VLBI (very long baseline interferometry)/delta DOR (differential one-way ranging); continuous tracks; segmented tracks; gap-to-track ratio; and override or block-out of requirements. The scheduling models now include conflict identification for SOA(start of activity), BOT (beginning of track), RFI (radio frequency interference), and equipment constraints. This software will search through all possible allocations while providing a best-effort solution at any time. The engine reschedules to accommodate individual emergency tracks in 0.2 second, and emergency antenna downtime in 0.2 second. The software handles doubling of one mission's track requests over one week (to 42 total) in 2.7 seconds. Further tests will be performed in the context of actual schedules.

77 FR 55837 - Information Collection Being Reviewed by the Federal Communications Commission

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

..., Satellite Network Stations and Space Stations. Form No.: FCC Form 312; Schedule S. Type of Review: Extension... determine the technical and legal qualifications of applicants or licensees to operate a station, transfer...

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra aids in Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

NASA Image and Video Library

2004-02-03

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra aids in Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

Cross support overview and operations concept for future space missions

NASA Technical Reports Server (NTRS)

Stallings, William; Kaufeler, Jean-Francois

1994-01-01

Ground networks must respond to the requirements of future missions, which include smaller sizes, tighter budgets, increased numbers, and shorter development schedules. The Consultative Committee for Space Data Systems (CCSDS) is meeting these challenges by developing a general cross support concept, reference model, and service specifications for Space Link Extension services for space missions involving cross support among Space Agencies. This paper identifies and bounds the problem, describes the need to extend Space Link services, gives an overview of the operations concept, and introduces complimentary CCSDS work on standardizing Space Link Extension services.

Representations and evolutionary operators for the scheduling of pump operations in water distribution networks.

PubMed

López-Ibáñez, Manuel; Prasad, T Devi; Paechter, Ben

2011-01-01

Reducing the energy consumption of water distribution networks has never had more significance. The greatest energy savings can be obtained by carefully scheduling the operations of pumps. Schedules can be defined either implicitly, in terms of other elements of the network such as tank levels; or explicitly, by specifying the time during which each pump is on/off. The traditional representation of explicit schedules is a string of binary values with each bit representing pump on/off status during a particular time interval. In this paper, we formally define and analyze two new explicit representations based on time-controlled triggers, where the maximum number of pump switches is established beforehand and the schedule may contain fewer than the maximum number of switches. In these representations, a pump schedule is divided into a series of integers with each integer representing the number of hours for which a pump is active/inactive. This reduces the number of potential schedules compared to the binary representation, and allows the algorithm to operate on the feasible region of the search space. We propose evolutionary operators for these two new representations. The new representations and their corresponding operations are compared with the two most-used representations in pump scheduling, namely, binary representation and level-controlled triggers. A detailed statistical analysis of the results indicates which parameters have the greatest effect on the performance of evolutionary algorithms. The empirical results show that an evolutionary algorithm using the proposed representations is an improvement over the results obtained by a recent state of the art hybrid genetic algorithm for pump scheduling using level-controlled triggers.

NCC simulation model. Phase 2: Simulating the operations of the Network Control Center and NCC message manual

NASA Technical Reports Server (NTRS)

Benjamin, Norman M.; Gill, Tepper; Charles, Mary

1994-01-01

The network control center (NCC) provides scheduling, monitoring, and control of services to the NASA space network. The space network provides tracking and data acquisition services to many low-earth orbiting spacecraft. This report describes the second phase in the development of simulation models for the FCC. Phase one concentrated on the computer systems and interconnecting network.Phase two focuses on the implementation of the network message dialogs and the resources controlled by the NCC. Performance measures were developed along with selected indicators of the NCC's operational effectiveness.The NCC performance indicators were defined in terms of the following: (1) transfer rate, (2) network delay, (3) channel establishment time, (4) line turn around time, (5) availability, (6) reliability, (7) accuracy, (8) maintainability, and (9) security. An NCC internal and external message manual is appended to this report.

Space time neural networks for tether operations in space

NASA Technical Reports Server (NTRS)

Lea, Robert N.; Villarreal, James A.; Jani, Yashvant; Copeland, Charles

1993-01-01

A space shuttle flight scheduled for 1992 will attempt to prove the feasibility of operating tethered payloads in earth orbit. due to the interaction between the Earth's magnetic field and current pulsing through the tether, the tethered system may exhibit a circular transverse oscillation referred to as the 'skiprope' phenomenon. Effective damping of skiprope motion depends on rapid and accurate detection of skiprope magnitude and phase. Because of non-linear dynamic coupling, the satellite attitude behavior has characteristic oscillations during the skiprope motion. Since the satellite attitude motion has many other perturbations, the relationship between the skiprope parameters and attitude time history is very involved and non-linear. We propose a Space-Time Neural Network implementation for filtering satellite rate gyro data to rapidly detect and predict skiprope magnitude and phase. Training and testing of the skiprope detection system will be performed using a validated Orbital Operations Simulator and Space-Time Neural Network software developed in the Software Technology Branch at NASA's Lyndon B. Johnson Space Center.

Resource constrained design of artificial neural networks using comparator neural network

NASA Technical Reports Server (NTRS)

Wah, Benjamin W.; Karnik, Tanay S.

1992-01-01

We present a systematic design method executed under resource constraints for automating the design of artificial neural networks using the back error propagation algorithm. Our system aims at finding the best possible configuration for solving the given application with proper tradeoff between the training time and the network complexity. The design of such a system is hampered by three related problems. First, there are infinitely many possible network configurations, each may take an exceedingly long time to train; hence, it is impossible to enumerate and train all of them to completion within fixed time, space, and resource constraints. Second, expert knowledge on predicting good network configurations is heuristic in nature and is application dependent, rendering it difficult to characterize fully in the design process. A learning procedure that refines this knowledge based on examples on training neural networks for various applications is, therefore, essential. Third, the objective of the network to be designed is ill-defined, as it is based on a subjective tradeoff between the training time and the network cost. A design process that proposes alternate configurations under different cost-performance tradeoff is important. We have developed a Design System which schedules the available time, divided into quanta, for testing alternative network configurations. Its goal is to select/generate and test alternative network configurations in each quantum, and find the best network when time is expended. Since time is limited, a dynamic schedule that determines the network configuration to be tested in each quantum is developed. The schedule is based on relative comparison of predicted training times of alternative network configurations using comparator network paradigm. The comparator network has been trained to compare training times for a large variety of traces of TSSE-versus-time collected during back-propagation learning of various applications.

A new technology for manufacturing scheduling derived from space system operations

NASA Technical Reports Server (NTRS)

Hornstein, R. S.; Willoughby, J. K.

1993-01-01

A new technology for producing finite capacity schedules has been developed in response to complex requirements for operating space systems such as the Space Shuttle, the Space Station, and the Deep Space Network for telecommunications. This technology has proven its effectiveness in manufacturing environments where popular scheduling techniques associated with Materials Resources Planning (MRPII) and with factory simulation are not adequate for shop-floor work planning and control. The technology has three components. The first is a set of data structures that accommodate an extremely general description of a factory's resources, its manufacturing activities, and the constraints imposed by the environment. The second component is a language and set of software utilities that enable a rapid synthesis of functional capabilities. The third component is an algorithmic architecture called the Five Ruleset Model which accommodates the unique needs of each factory. Using the new technology, systems can model activities that generate, consume, and/or obligate resources. This allows work-in-process (WIP) to be generated and used; it permits constraints to be imposed or intermediate as well as finished goods inventories. It is also possible to match as closely as possible both the current factory state and future conditions such as promise dates. Schedule revisions can be accommodated without impacting the entire production schedule. Applications have been successful in both discrete and process manufacturing environments. The availability of a high-quality finite capacity production planning capability enhances the data management capabilities of MRP II systems. These schedules can be integrated with shop-floor data collection systems and accounting systems. Using the new technology, semi-custom systems can be developed at costs that are comparable to products that do not have equivalent functional capabilities and/or extensibility.

The 1991 Goddard Conference on Space Applications of Artificial Intelligence

NASA Technical Reports Server (NTRS)

Rash, James L. (Editor)

1991-01-01

The purpose of this annual conference is to provide a forum in which current research and development directed at space applications of artificial intelligence can be presented and discussed. The papers in this proceeding fall into the following areas: Planning and scheduling, fault monitoring/diagnosis/recovery, machine vision, robotics, system development, information management, knowledge acquisition and representation, distributed systems, tools, neural networks, and miscellaneous applications.

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra (facing camera) aids in Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

NASA Image and Video Library

2004-02-03

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra (facing camera) aids in Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra talks to a technician (off-camera) during Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

NASA Image and Video Library

2004-02-03

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra talks to a technician (off-camera) during Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

Deep space network software cost estimation model

NASA Technical Reports Server (NTRS)

Tausworthe, R. C.

1981-01-01

A parametric software cost estimation model prepared for Deep Space Network (DSN) Data Systems implementation tasks is presented. The resource estimation model incorporates principles and data from a number of existing models. The model calibrates task magnitude and difficulty, development environment, and software technology effects through prompted responses to a set of approximately 50 questions. Parameters in the model are adjusted to fit DSN software life cycle statistics. The estimation model output scales a standard DSN Work Breakdown Structure skeleton, which is then input into a PERT/CPM system, producing a detailed schedule and resource budget for the project being planned.

Mixed Integer Programming and Heuristic Scheduling for Space Communication Networks

NASA Technical Reports Server (NTRS)

Lee, Charles H.; Cheung, Kar-Ming

2012-01-01

In this paper, we propose to solve the constrained optimization problem in two phases. The first phase uses heuristic methods such as the ant colony method, particle swarming optimization, and genetic algorithm to seek a near optimal solution among a list of feasible initial populations. The final optimal solution can be found by using the solution of the first phase as the initial condition to the SQP algorithm. We demonstrate the above problem formulation and optimization schemes with a large-scale network that includes the DSN ground stations and a number of spacecraft of deep space missions.

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra (second from right) talks with workers in the Space Station Processing Facility about the Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. . The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

NASA Image and Video Library

2004-02-03

KENNEDY SPACE CENTER, FLA. - Astronaut Tim Kopra (second from right) talks with workers in the Space Station Processing Facility about the Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. . The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

Edison Demonstration of Smallsat Networks

NASA Technical Reports Server (NTRS)

Westley, Deborah; Martinez, Andres; Petro, Andrew

2015-01-01

The goal of NASA's Edison Demonstration of Smallsat Networks (EDSN) mission is to demonstrate interactive satellite swarms capable of collecting, exchanging and transmitting multi-point scientific measurements. Satellite swarms enable a wide array of scientific, commercial and academic research not achievable with a single satellite. The EDSN satellites are scheduled to be launched into space as secondary payloads on the first flight of the Super Strypi launch vehicle no earlier than Oct. 29, 2015.

ESTRACK Support for CCSDS Space Communication Cross Support Service Management

NASA Astrophysics Data System (ADS)

Dreihahn, H.; Unal, M.; Hoffmann, A.

2011-08-01

The CCSDS Recommended Standard for Space Communication Cross Support Service Management (SCCS SM) published as Blue Book in August 2009 is intended to provide standardised interfaces to negotiate, schedule, and manage the support of space missions by ground station network operators. ESA as a member of CCSDS has actively supported the development of the SCCS SM standard and is obviously interested in adopting it. Support of SCCS SM conforming interfaces and procedures includes:• Provision of SCCS SM conforming interfaces to non ESA missions;• Use of SCCS SM interfaces provided by other ground station operators to manage cross support of ESA missions;• In longer terms potentially use of SCCS SM interfaces and procedures also internally for support of ESA missions by ESTRACK.In the recent years ESOC has automated management and scheduling of ESA Tracking Network (ESTRACK) services by the specification, development, and deployment of the ESTRACK Management System (EMS), more specifically its planning and scheduling components ESTRACK Planning System and ESTRACK Scheduling System. While full support of the SCCS SM standard will involve also other elements of the ground segment operated by ESOC such as the Flight Dynamic System, EMS is at the core of service management and it is therefore appropriate to initially focus on the question to what extent EMS can support SCCS SM. This paper presents results of the initial analysis phase. After briefly presenting the SCCS SM standard and the relevant components of the ESTRACK management system, we will discuss the initial deployment options, open issues and a tentative roadmap for the way to proceed. Obviously the adoption of a cross support standard requires and discussion and coordination of the involved parties and agencies, especially in the light of the fact that the SCCS SM standard has many optional parts.

R and T report: Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Soffen, Gerald A. (Editor)

1993-01-01

The 1993 Research and Technology Report for Goddard Space Flight Center is presented. Research covered areas such as (1) flight projects; (2) space sciences including cosmology, high energy, stars and galaxies, and the solar system; (3) earth sciences including process modeling, hydrology/cryology, atmospheres, biosphere, and solid earth; (4) networks, planning, and information systems including support for mission operations, data distribution, advanced software and systems engineering, and planning/scheduling; and (5) engineering and materials including spacecraft systems, material and testing, optics and photonics and robotics.

Scheduling: A guide for program managers

NASA Technical Reports Server (NTRS)

1994-01-01

The following topics are discussed concerning scheduling: (1) milestone scheduling; (2) network scheduling; (3) program evaluation and review technique; (4) critical path method; (5) developing a network; (6) converting an ugly duckling to a swan; (7) network scheduling problem; (8) (9) network scheduling when resources are limited; (10) multi-program considerations; (11) influence on program performance; (12) line-of-balance technique; (13) time management; (14) recapitulization; and (15) analysis.

Gigabit Network Communications Research

DTIC Science & Technology

1992-12-31

additional BPF channels, raw bytesync support for video codecs, and others. All source file modifications were logged with RCS. Source and object trees were...34 (RFCs). 20 RFCs were published this quarter: RFC 1366: Gerich, E., " Guidelines for Management of IP Address Space", Merit, October 1992. RFC 1367...Topolcic, C., "Schedule for IP Address Space Management Guidelines ", CNRI, October 1992. RFC 1368: McMaster, D. (Synoptics Communications, Inc.), K

SpaceFibre: The Standard and the Multi-Lane Layer

NASA Astrophysics Data System (ADS)

Parkes, Steve; McClements, Chris; McLaren, David; Florit, Albert Ferrer; Gonzalez Villafranca, Alberto

2016-08-01

SpaceFibre is a new standard for spacecraft on-board data-handling networks, initially designed to deliver multi-Gbit/s data rates for synthetic aperture radar and high-resolution, multi-spectral imaging instruments, The addition of quality of service (QoS) and fault detection, isolation and recovery (FDIR) capabilities to SpaceFibre has resulted in a unified network technology. SpaceFibre provides high bandwidth, low latency, fault isolation and recovery suitable for space applications, and novel QoS that combines priority, bandwidth reservation and scheduling and which provides babbling node protection. SpaceFibre is backwards compatible with the widely used SpaceWire standard at the network level allowing simple interconnection of existing SpaceWire equipment to a SpaceFibre link or network.Developed by STAR-Dundee and the University of Dundee for the European Space Agency (ESA) SpaceFibre is able to operate over fibre-optic and electrical cable. A single lane of SpaceFibre comprises four signals (TX+/- and RX+/-) and supports data rates of 2 Gbits/s (2.5 Gbits/s data signalling rate) with data rates up to 5 Gbits/s already planned.Several lanes can operate together to provide a multi- lane link. Multi-laning increases the data-rate to well over 20 Gbits/s.This paper details the current state of SpaceFibre which is now in the process of formal standardisation by the European Cooperation for Space Standardization (ECSS). The multi-lane layer of SpaceFibre is then described.

Nodes

NASA Technical Reports Server (NTRS)

Hanson, John; Martinez, Andres; Petro, Andrew

2015-01-01

Nodes is a technology demonstration mission that is scheduled for launch to the International SpaceStation no earlier than Nov.19, 2015. The two Nodes satellites will be deployed from the Station in early 2016 todemonstrate new network capabilities critical to the operation of swarms of spacecraft. They will demonstrate the ability ofmulti spacecraft swarms to receive and distribute ground commands, exchange information periodically, andautonomously configure the network by determining which spacecraft should communicate with the ground each day ofthe mission.

A global spacecraft control network for spacecraft autonomy research

NASA Technical Reports Server (NTRS)

Kitts, Christopher A.

1996-01-01

The development and implementation of the Automated Space System Experimental Testbed (ASSET) space operations and control network, is reported on. This network will serve as a command and control architecture for spacecraft operations and will offer a real testbed for the application and validation of advanced autonomous spacecraft operations strategies. The proposed network will initially consist of globally distributed amateur radio ground stations at locations throughout North America and Europe. These stations will be linked via Internet to various control centers. The Stanford (CA) control center will be capable of human and computer based decision making for the coordination of user experiments, resource scheduling and fault management. The project's system architecture is described together with its proposed use as a command and control system, its value as a testbed for spacecraft autonomy research, and its current implementation.

Deep Space Network-Wide Portal Development: Planning Service Pilot Project

NASA Technical Reports Server (NTRS)

Doneva, Silviya

2011-01-01

The Deep Space Network (DSN) is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. DSN provides the vital two-way communications link that guides and controls planetary explorers, and brings back the images and new scientific information they collect. In an attempt to streamline operations and improve overall services provided by the Deep Space Network a DSN-wide portal is under development. The project is one step in a larger effort to centralize the data collected from current missions including user input parameters for spacecraft to be tracked. This information will be placed into a principal repository where all operations related to the DSN are stored. Furthermore, providing statistical characterization of data volumes will help identify technically feasible tracking opportunities and more precise mission planning by providing upfront scheduling proposals. Business intelligence tools are to be incorporated in the output to deliver data visualization.

FASTER - A tool for DSN forecasting and scheduling

NASA Technical Reports Server (NTRS)

Werntz, David; Loyola, Steven; Zendejas, Silvino

1993-01-01

FASTER (Forecasting And Scheduling Tool for Earth-based Resources) is a suite of tools designed for forecasting and scheduling JPL's Deep Space Network (DSN). The DSN is a set of antennas and other associated resources that must be scheduled for satellite communications, astronomy, maintenance, and testing. FASTER consists of MS-Windows based programs that replace two existing programs (RALPH and PC4CAST). FASTER was designed to be more flexible, maintainable, and user friendly. FASTER makes heavy use of commercial software to allow for customization by users. FASTER implements scheduling as a two pass process: the first pass calculates a predictive profile of resource utilization; the second pass uses this information to calculate a cost function used in a dynamic programming optimization step. This information allows the scheduler to 'look ahead' at activities that are not as yet scheduled. FASTER has succeeded in allowing wider access to data and tools, reducing the amount of effort expended and increasing the quality of analysis.

Visualizing and Integrating AFSCN Utilization into a Common Operational Picture

NASA Astrophysics Data System (ADS)

Hays, B.; Carlile, A.; Mitchell, T.

The Department of Defense (DoD) and the 50th Space Network Operations Group Studies and Analysis branch (50th SCS/SCXI), located at Schriever AFB Colorado, face the unique challenge of forecasting the expected near term and future utilization of the Air Force Satellite Control Network (AFSCN). The forecasting timeframe covers the planned load from the current date to ten years out. The various satellite missions, satellite requirements, orbital regions, and ground architecture dynamics provide the model inputs and constraints that are used in generating the forecasted load. The AFSCN is the largest network the Air Force uses to control satellites worldwide. Each day, network personnel perform over 500 scheduled events-from satellite maneuvers to critical data downloads. The Forecasting Objective is to provide leadership with the insights necessary to manage the network today and tomorrow. For both today's needs and future needs, SCXI develops AFSCN utilization forecasts to optimize the ground system's coverage and capacity to meet user satellite requirements. SCXI also performs satellite program specific studies to determine network support feasibility. STK and STK Scheduler form the core of the tools used by SCXI. To establish this tool suite, we had to evaluate, evolve, and validate both the COTS products and our own developed code and processes. This began with calibrating the network model to emulate the real life scheduling environment of the AFSCN. Multiple STK Scheduler optimizing (de-confliction) algorithms, including Multi-Pass, Sequential, Random, and Neural, were evaluated and adjusted to determine applicability to the model and the accuracy of the prediction. Additionally, the scheduling Figure of Merit (FOM), which permits custom weighting of various parameters, was analyzed and tested to achieve the most accurate real life result. With the inherent capabilities of STK and the ability to wrap and automate output, SCXI is now able to visually communicate satellite loads in a manner never seen before in AFSCN management meetings. Scenarios such as regional antenna load stress, satellite missed opportunities, and the overall network "big picture" can be visually displayed in 3D versus the textual and line graph methods used for many years. This is the first step towards an integrated space awareness picture with an operational focus. SCXI is working on taking the visual forecast concept farther and begin fusing multiple sources of data to build a 50 SW Common Operating Picture (COP). The vision is to integrate more effective orbital determination processes, resource outages, current and forecasted satellite mission requirements, and future architectural changes into a real-time visual status to enable quick and responsive decisions. This COP would be utilized in a Wing Operations Center to provide up to the minute network status on where satellites are, which ground resources are in contact with them, and what resources are down. The ability to quickly absorb and process this data will enhance decision analysis and save valuable time in both day to day operations and wartime scenarios.

Mission and Assets Database

NASA Technical Reports Server (NTRS)

Baldwin, John; Zendejas, Silvino; Gutheinz, Sandy; Borden, Chester; Wang, Yeou-Fang

2009-01-01

Mission and Assets Database (MADB) Version 1.0 is an SQL database system with a Web user interface to centralize information. The database stores flight project support resource requirements, view periods, antenna information, schedule, and forecast results for use in mid-range and long-term planning of Deep Space Network (DSN) assets.

Global Precipitation Measurement (GPM) Mission

NASA Image and Video Library

2014-02-26

Members of the weather team prepare reports for the Global Precipitation Measurement (GPM) Core Observatory Launch Readiness Review (LRR) with Chief officers from Mitsubishi Heavy Industries, Ltd., the Japan Aerospace Exploration Agency (JAXA), and NASA, on Wednesday, Feb. 26, 2014 at Tanegashima Space Center, Japan. The GPM spacecraft is scheduled to launch aboard an H-IIA rocket early on the morning of Feb. 28 Japan time. At the meeting in the space center's Range Control Center, all preparations to date were reviewed and approval was given to proceed with launch on schedule. Once launched, the GPM spacecraft will collect information that unifies data from an international network of existing and future satellites to map global rainfall and snowfall every three hours. Photo Credit: (NASA/Bill Ingalls)

Global Precipitation Measurement (GPM) Mission

NASA Image and Video Library

2014-02-26

Art Azarbarzin, NASA Global Precipitation Measurement (GPM) project manager, left, participates in the GPM Launch Readiness Review (LRR) along with Chief officers from Mitsubishi Heavy Industries, Ltd., and the Japan Aerospace Exploration Agency (JAXA) on Wednesday, Feb. 26, 2014 at Tanegashima Space Center, Japan. The spacecraft is scheduled to launch aboard an H-IIA rocket early on the morning of Feb. 28 Japan time. At the meeting in the space center's Range Control Center, all preparations to date were reviewed and approval was given to proceed with launch on schedule. Once launched, the GPM spacecraft will collect information that unifies data from an international network of existing and future satellites to map global rainfall and snowfall every three hours. Photo Credit: (NASA/Bill Ingalls)

Contact Graph Routing Enhancements Developed in ION for DTN

NASA Technical Reports Server (NTRS)

Segui, John S.; Burleigh, Scott

2013-01-01

The Interplanetary Overlay Network (ION) software suite is an open-source, flight-ready implementation of networking protocols including the Delay/Disruption Tolerant Networking (DTN) Bundle Protocol (BP), the CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol (CFDP), and many others including the Contact Graph Routing (CGR) DTN routing system. While DTN offers the capability to tolerate disruption and long signal propagation delays in transmission, without an appropriate routing protocol, no data can be delivered. CGR was built for space exploration networks with scheduled communication opportunities (typically based on trajectories and orbits), represented as a contact graph. Since CGR uses knowledge of future connectivity, the contact graph can grow rather large, and so efficient processing is desired. These enhancements allow CGR to scale to predicted NASA space network complexities and beyond. This software improves upon CGR by adopting an earliest-arrival-time cost metric and using the Dijkstra path selection algorithm. Moving to Dijkstra path selection also enables construction of an earliest- arrival-time tree for multicast routing. The enhancements have been rolled into ION 3.0 available on sourceforge.net.

Space Surveillance Network (SSN) Optical Augmentation (SOA)

DTIC Science & Technology

1999-04-01

physical characteristics, and the geocentric and topocentric positions of each satellite in the deep space object catalog. The SKYMAP propagator...maintains the geocentric and topocentric positions and recomputes the position of each object several times a minute. For each scheduling...AINTENANCE Mission Personnel ( Staffing ) Officers 0.0 0.0 0.0 0.0 $90K/person (0) Enlisted 0.0 0.0 0.0 0.0 $45K/person (0) Contractor 20.0

The Falcon Telescope Network

NASA Astrophysics Data System (ADS)

Chun, F.; Tippets, R.; Dearborn, M.; Gresham, K.; Freckleton, R.; Douglas, M.

2014-09-01

The Falcon Telescope Network (FTN) is a global network of small aperture telescopes developed by the Center for Space Situational Awareness Research in the Department of Physics at the United States Air Force Academy (USAFA). Consisting of commercially available equipment, the FTN is a collaborative effort between USAFA and other educational institutions ranging from two- and four-year colleges to major research universities. USAFA provides the equipment (e.g. telescope, mount, camera, filter wheel, dome, weather station, computers and storage devices) while the educational partners provide the building and infrastructure to support an observatory. The user base includes USAFA along with K-12 and higher education faculty and students. Since the FTN has a general use purpose, objects of interest include satellites, astronomical research, and STEM support images. The raw imagery, all in the public domain, will be accessible to FTN partners and will be archived at USAFA in the Cadet Space Operations Center. FTN users will be able to submit observational requests via a web interface. The requests will then be prioritized based on the type of user, the object of interest, and a user-defined priority. A network wide schedule will be developed every 24 hours and each FTN site will autonomously execute its portion of the schedule. After an observational request is completed, the FTN user will receive notification of collection and a link to the data. The Falcon Telescope Network is an ambitious endeavor, but demonstrates the cooperation that can be achieved by multiple educational institutions.

Current Status of the International Lunar Network (ILN) Anchor Nodes Mission

NASA Astrophysics Data System (ADS)

Cohen, Barbara; Bassler, J.; Harris, D.; Morse, B.; Reed, C.; Kirby, K.; Eng, D.

2009-09-01

NASA's Science Mission Directorate's (SMD) International Lunar Network Anchor Nodes Mission continues its concept development and is scheduled to complete the first formal milestone gate of a Mission Concept Review (MCR) in late 2009. The mission will establish two-four nodes of the International Lunar Network (ILN), a network of lunar geophysical stations envisioned to be emplaced by the many nations collaborating on this joint endeavor. This mission will operate over six years or more and make significant progress in satisfying many of the National Research Council's lunar science objectives, while strategically contributing to the U.S. Vision for Space Exploration Policy's objective for a robust robotic lunar program. This paper will provide a status report on the ILN Anchor Nodes mission and overview of the concept to date, which is being implemented jointly by NASA's Marshall Space Flight Center and The Johns Hopkins University Applied Physics Laboratory.

Delay and Disruption Tolerant Networking MACHETE Model

NASA Technical Reports Server (NTRS)

Segui, John S.; Jennings, Esther H.; Gao, Jay L.

2011-01-01

To verify satisfaction of communication requirements imposed by unique missions, as early as 2000, the Communications Networking Group at the Jet Propulsion Laboratory (JPL) saw the need for an environment to support interplanetary communication protocol design, validation, and characterization. JPL's Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE), described in Simulator of Space Communication Networks (NPO-41373) NASA Tech Briefs, Vol. 29, No. 8 (August 2005), p. 44, combines various commercial, non-commercial, and in-house custom tools for simulation and performance analysis of space networks. The MACHETE environment supports orbital analysis, link budget analysis, communications network simulations, and hardware-in-the-loop testing. As NASA is expanding its Space Communications and Navigation (SCaN) capabilities to support planned and future missions, building infrastructure to maintain services and developing enabling technologies, an important and broader role is seen for MACHETE in design-phase evaluation of future SCaN architectures. To support evaluation of the developing Delay Tolerant Networking (DTN) field and its applicability for space networks, JPL developed MACHETE models for DTN Bundle Protocol (BP) and Licklider/Long-haul Transmission Protocol (LTP). DTN is an Internet Research Task Force (IRTF) architecture providing communication in and/or through highly stressed networking environments such as space exploration and battlefield networks. Stressed networking environments include those with intermittent (predictable and unknown) connectivity, large and/or variable delays, and high bit error rates. To provide its services over existing domain specific protocols, the DTN protocols reside at the application layer of the TCP/IP stack, forming a store-and-forward overlay network. The key capabilities of the Bundle Protocol include custody-based reliability, the ability to cope with intermittent connectivity, the ability to take advantage of scheduled and opportunistic connectivity, and late binding of names to addresses.

Ethernet for Space Flight Applications

NASA Technical Reports Server (NTRS)

Webb, Evan; Day, John H. (Technical Monitor)

2002-01-01

NASA's Goddard Space Flight Center (GSFC) is adapting current data networking technologies to fly on future spaceflight missions. The benefits of using commercially based networking standards and protocols have been widely discussed and are expected to include reduction in overall mission cost, shortened integration and test (I&T) schedules, increased operations flexibility, and hardware and software upgradeability/scalability with developments ongoing in the commercial world. The networking effort is a comprehensive one encompassing missions ranging from small University Explorer (UNEX) class spacecraft to large observatories such as the Next Generation Space Telescope (NGST). Mission aspects such as flight hardware and software, ground station hardware and software, operations, RF communications, and security (physical and electronic) are all being addressed to ensure a complete end-to-end system solution. One of the current networking development efforts at GSFC is the SpaceLAN (Spacecraft Local Area Network) project, development of a space-qualifiable Ethernet network. To this end we have purchased an IEEE 802.3-compatible 10/100/1000 Media Access Control (MAC) layer Intellectual Property (IP) core and are designing a network node interface (NNI) and associated network components such as a switch. These systems will ultimately allow the replacement of the typical MIL-STD-1553/1773 and custom interfaces that inhabit most spacecraft. In this paper we will describe our current Ethernet NNI development along with a novel new space qualified physical layer that will be used in place of the standard interfaces. We will outline our plans for development of space qualified network components that will allow future spacecraft to operate in significant radiation environments while using a single onboard network for reliable commanding and data transfer. There will be a brief discussion of some issues surrounding system implications of a flight Ethernet. Finally, we will show an onboard network architecture for a proposed new mission using Ethernet for science data transport.

Conflict-Aware Scheduling Algorithm

NASA Technical Reports Server (NTRS)

Wang, Yeou-Fang; Borden, Chester

2006-01-01

conflict-aware scheduling algorithm is being developed to help automate the allocation of NASA s Deep Space Network (DSN) antennas and equipment that are used to communicate with interplanetary scientific spacecraft. The current approach for scheduling DSN ground resources seeks to provide an equitable distribution of tracking services among the multiple scientific missions and is very labor intensive. Due to the large (and increasing) number of mission requests for DSN services, combined with technical and geometric constraints, the DSN is highly oversubscribed. To help automate the process, and reduce the DSN and spaceflight project labor effort required for initiating, maintaining, and negotiating schedules, a new scheduling algorithm is being developed. The scheduling algorithm generates a "conflict-aware" schedule, where all requests are scheduled based on a dynamic priority scheme. The conflict-aware scheduling algorithm allocates all requests for DSN tracking services while identifying and maintaining the conflicts to facilitate collaboration and negotiation between spaceflight missions. These contrast with traditional "conflict-free" scheduling algorithms that assign tracks that are not in conflict and mark the remainder as unscheduled. In the case where full schedule automation is desired (based on mission/event priorities, fairness, allocation rules, geometric constraints, and ground system capabilities/ constraints), a conflict-free schedule can easily be created from the conflict-aware schedule by removing lower priority items that are in conflict.

Large Phased Array Radar Using Networked Small Parabolic Reflectors

NASA Technical Reports Server (NTRS)

Amoozegar, Farid

2006-01-01

Multifunction phased array systems with radar, telecom, and imaging applications have already been established for flat plate phased arrays of dipoles, or waveguides. In this paper the design trades and candidate options for combining the radar and telecom functions of the Deep Space Network (DSN) into a single large transmit array of small parabolic reflectors will be discussed. In particular the effect of combing the radar and telecom functions on the sizes of individual antenna apertures and the corresponding spacing between the antenna elements of the array will be analyzed. A heterogeneous architecture for the DSN large transmit array is proposed to meet the radar and telecom requirements while considering the budget, scheduling, and strategic planning constrains.

What we were asked to do

NASA Technical Reports Server (NTRS)

1991-01-01

Recommendations are made after 32 interviews, lesson identification, lesson analysis, and mission characteristics identification. The major recommendations are as follows: (1) to develop end-to-end planning and scheduling operations concepts by mission class and to ensure their consideration in system life cycle documentation; (2) to create an organizational infrastructure at the Code 500 level, supported by a Directorate level steering committee with project representation, responsible for systems engineering of end-to-end planning and scheduling systems; (3) to develop and refine mission capabilities to assess impacts of early mission design decisions on planning and scheduling; and (4) to emphasize operational flexibility in the development of the Advanced Space Network, other institutional resources, external (e.g., project) capabilities and resources, operational software and support tools.

Software for Allocating Resources in the Deep Space Network

NASA Technical Reports Server (NTRS)

Wang, Yeou-Fang; Borden, Chester; Zendejas, Silvino; Baldwin, John

2003-01-01

TIGRAS 2.0 is a computer program designed to satisfy a need for improved means for analyzing the tracking demands of interplanetary space-flight missions upon the set of ground antenna resources of the Deep Space Network (DSN) and for allocating those resources. Written in Microsoft Visual C++, TIGRAS 2.0 provides a single rich graphical analysis environment for use by diverse DSN personnel, by connecting to various data sources (relational databases or files) based on the stages of the analyses being performed. Notable among the algorithms implemented by TIGRAS 2.0 are a DSN antenna-load-forecasting algorithm and a conflict-aware DSN schedule-generating algorithm. Computers running TIGRAS 2.0 can also be connected using SOAP/XML to a Web services server that provides analysis services via the World Wide Web. TIGRAS 2.0 supports multiple windows and multiple panes in each window for users to view and use information, all in the same environment, to eliminate repeated switching among various application programs and Web pages. TIGRAS 2.0 enables the use of multiple windows for various requirements, trajectory-based time intervals during which spacecraft are viewable, ground resources, forecasts, and schedules. Each window includes a time navigation pane, a selection pane, a graphical display pane, a list pane, and a statistics pane.

Constraint based scheduling for the Goddard Space Flight Center distributed Active Archive Center's data archive and distribution system

NASA Technical Reports Server (NTRS)

Short, Nick, Jr.; Bedet, Jean-Jacques; Bodden, Lee; Boddy, Mark; White, Jim; Beane, John

1994-01-01

The Goddard Space Flight Center (GSFC) Distributed Active Archive Center (DAAC) has been operational since October 1, 1993. Its mission is to support the Earth Observing System (EOS) by providing rapid access to EOS data and analysis products, and to test Earth Observing System Data and Information System (EOSDIS) design concepts. One of the challenges is to ensure quick and easy retrieval of any data archived within the DAAC's Data Archive and Distributed System (DADS). Over the 15-year life of EOS project, an estimated several Petabytes (10(exp 15)) of data will be permanently stored. Accessing that amount of information is a formidable task that will require innovative approaches. As a precursor of the full EOS system, the GSFC DAAC with a few Terabits of storage, has implemented a prototype of a constraint-based task and resource scheduler to improve the performance of the DADS. This Honeywell Task and Resource Scheduler (HTRS), developed by Honeywell Technology Center in cooperation the Information Science and Technology Branch/935, the Code X Operations Technology Program, and the GSFC DAAC, makes better use of limited resources, prevents backlog of data, provides information about resources bottlenecks and performance characteristics. The prototype which is developed concurrently with the GSFC Version 0 (V0) DADS, models DADS activities such as ingestion and distribution with priority, precedence, resource requirements (disk and network bandwidth) and temporal constraints. HTRS supports schedule updates, insertions, and retrieval of task information via an Application Program Interface (API). The prototype has demonstrated with a few examples, the substantial advantages of using HTRS over scheduling algorithms such as a First In First Out (FIFO) queue. The kernel scheduling engine for HTRS, called Kronos, has been successfully applied to several other domains such as space shuttle mission scheduling, demand flow manufacturing, and avionics communications scheduling.

Pre-Scheduled and Self Organized Sleep-Scheduling Algorithms for Efficient K-Coverage in Wireless Sensor Networks

PubMed Central

Hwang, I-Shyan

2017-01-01

The K-coverage configuration that guarantees coverage of each location by at least K sensors is highly popular and is extensively used to monitor diversified applications in wireless sensor networks. Long network lifetime and high detection quality are the essentials of such K-covered sleep-scheduling algorithms. However, the existing sleep-scheduling algorithms either cause high cost or cannot preserve the detection quality effectively. In this paper, the Pre-Scheduling-based K-coverage Group Scheduling (PSKGS) and Self-Organized K-coverage Scheduling (SKS) algorithms are proposed to settle the problems in the existing sleep-scheduling algorithms. Simulation results show that our pre-scheduled-based KGS approach enhances the detection quality and network lifetime, whereas the self-organized-based SKS algorithm minimizes the computation and communication cost of the nodes and thereby is energy efficient. Besides, SKS outperforms PSKGS in terms of network lifetime and detection quality as it is self-organized. PMID:29257078

Advanced systems engineering and network planning support

NASA Technical Reports Server (NTRS)

Walters, David H.; Barrett, Larry K.; Boyd, Ronald; Bazaj, Suresh; Mitchell, Lionel; Brosi, Fred

1990-01-01

The objective of this task was to take a fresh look at the NASA Space Network Control (SNC) element for the Advanced Tracking and Data Relay Satellite System (ATDRSS) such that it can be made more efficient and responsive to the user by introducing new concepts and technologies appropriate for the 1997 timeframe. In particular, it was desired to investigate the technologies and concepts employed in similar systems that may be applicable to the SNC. The recommendations resulting from this study include resource partitioning, on-line access to subsets of the SN schedule, fluid scheduling, increased use of demand access on the MA service, automating Inter-System Control functions using monitor by exception, increase automation for distributed data management and distributed work management, viewing SN operational control in terms of the OSI Management framework, and the introduction of automated interface management.

Applications of dynamic scheduling technique to space related problems: Some case studies

NASA Astrophysics Data System (ADS)

Nakasuka, Shinichi; Ninomiya, Tetsujiro

1994-10-01

The paper discusses the applications of 'Dynamic Scheduling' technique, which has been invented for the scheduling of Flexible Manufacturing System, to two space related scheduling problems: operation scheduling of a future space transportation system, and resource allocation in a space system with limited resources such as space station or space shuttle.

SMC: SCENIC Model Control

NASA Technical Reports Server (NTRS)

Srivastava, Priyaka; Kraus, Jeff; Murawski, Robert; Golden, Bertsel, Jr.

2015-01-01

NASAs Space Communications and Navigation (SCaN) program manages three active networks: the Near Earth Network, the Space Network, and the Deep Space Network. These networks simultaneously support NASA missions and provide communications services to customers worldwide. To efficiently manage these resources and their capabilities, a team of student interns at the NASA Glenn Research Center is developing a distributed system to model the SCaN networks. Once complete, the system shall provide a platform that enables users to perform capacity modeling of current and prospective missions with finer-grained control of information between several simulation and modeling tools. This will enable the SCaN program to access a holistic view of its networks and simulate the effects of modifications in order to provide NASA with decisional information. The development of this capacity modeling system is managed by NASAs Strategic Center for Education, Networking, Integration, and Communication (SCENIC). Three primary third-party software tools offer their unique abilities in different stages of the simulation process. MagicDraw provides UMLSysML modeling, AGIs Systems Tool Kit simulates the physical transmission parameters and de-conflicts scheduled communication, and Riverbed Modeler (formerly OPNET) simulates communication protocols and packet-based networking. SCENIC developers are building custom software extensions to integrate these components in an end-to-end space communications modeling platform. A central control module acts as the hub for report-based messaging between client wrappers. Backend databases provide information related to mission parameters and ground station configurations, while the end user defines scenario-specific attributes for the model. The eight SCENIC interns are working under the direction of their mentors to complete an initial version of this capacity modeling system during the summer of 2015. The intern team is composed of four students in Computer Science, two in Computer Engineering, one in Electrical Engineering, and one studying Space Systems Engineering.

Spitzer Operations: Scheduling the Out Years

NASA Technical Reports Server (NTRS)

Mahoney, William A.; Effertz, Mark J.; Fisher, Mark E.; Garcia, Lisa J.; Hunt, Joseph C. Jr.; Mannings, Vincent; McElroy, Douglas B.; Scire, Elena

2012-01-01

Spitzer Warm Mission operations have remained robust and exceptionally efficient since the cryogenic mission ended in mid-2009. The distance to the now exceeds 1 AU, making telecommunications increasingly difficult; however, analysis has shown that two-way communication could be maintained through at least 2017 with minimal loss in observing efficiency. The science program continues to emphasize the characterization of exoplanets, time domain studies, and deep surveys, all of which can impose interesting scheduling constraints. Recent changes have significantly improved on-board data compression, which both enables certain high volume observations and reduces Spitzer's demand for competitive Deep Space Network resources.

Developing algorithm for the critical care physician scheduling

NASA Astrophysics Data System (ADS)

Lee, Hyojun; Pah, Adam; Amaral, Luis; Northwestern Memorial Hospital Collaboration

Understanding the social network has enabled us to quantitatively study social phenomena such as behaviors in adoption and propagation of information. However, most work has been focusing on networks of large heterogeneous communities, and little attention has been paid to how work-relevant information spreads within networks of small and homogeneous groups of highly trained individuals, such as physicians. Within the professionals, the behavior patterns and the transmission of information relevant to the job are dependent not only on the social network between the employees but also on the schedules and teams that work together. In order to systematically investigate the dependence of the spread of ideas and adoption of innovations on a work-environment network, we sought to construct a model for the interaction network of critical care physicians at Northwestern Memorial Hospital (NMH) based on their work schedules. We inferred patterns and hidden rules from past work schedules such as turnover rates. Using the characteristics of the work schedules of the physicians and their turnover rates, we were able to create multi-year synthetic work schedules for a generic intensive care unit. The algorithm for creating shift schedules can be applied to other schedule dependent networks ARO1.

Distributed network scheduling

NASA Technical Reports Server (NTRS)

Clement, Bradley J.; Schaffer, Steven R.

2004-01-01

Distributed Network Scheduling is the scheduling of future communications of a network by nodes in the network. This report details software for doing this onboard spacecraft in a remote network. While prior work on distributed scheduling has been applied to remote spacecraft networks, the software reported here focuses on modeling communication activities in greater detail and including quality of service constraints. Our main results are based on a Mars network of spacecraft and include identifying a maximum opportunity of improving traverse exploration rate a factor of three; a simulation showing reduction in one-way delivery times from a rover to Earth from as much as 5 to 1.5 hours; simulated response to unexpected events averaging under an hour onboard; and ground schedule generation ranging from seconds to 50 minutes for 15 to 100 communication goals.

TDRS-M NASA Social

NASA Image and Video Library

2017-08-17

Neil Mallik, NASA deputy network director for Human Spaceflight, speaks to members of social media in the Kennedy Space Center’s Press Site auditorium. The briefing focused on preparations to launch NASA's Tracking and Data Relay Satellite, TDRS-M. The latest spacecraft destined for the agency's constellation of communications satellites, TDRS-M will allow nearly continuous contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. Liftoff atop a United Launch Alliance Atlas V rocket is scheduled to take place from Space Launch Complex 41 at Cape Canaveral Air Force Station at 8:03 a.m. EDT Aug. 18.

Critical issues in assuring long lifetime and fail-safe operation of optical communications network

NASA Astrophysics Data System (ADS)

Paul, Dilip K.

1993-09-01

Major factors in assuring long lifetime and fail-safe operation in optical communications networks are reviewed in this paper. Reliable functionality to design specifications, complexity of implementation, and cost are the most critical issues. As economics is the driving force to set the goals as well as priorities for the design, development, safe operation, and maintenance schedules of reliable networks, a balance is sought between the degree of reliability enhancement, cost, and acceptable outage of services. Protecting both the link and the network with high reliability components, hardware duplication, and diversity routing can ensure the best network availability. Case examples include both fiber optic and lasercom systems. Also, the state-of-the-art reliability of photonics in space environment is presented.

Escalator: An Autonomous Scheduling Scheme for Convergecast in TSCH

PubMed Central

Oh, Sukho; Hwang, DongYeop; Kim, Ki-Hyung; Kim, Kangseok

2018-01-01

Time Slotted Channel Hopping (TSCH) is widely used in the industrial wireless sensor networks due to its high reliability and energy efficiency. Various timeslot and channel scheduling schemes have been proposed for achieving high reliability and energy efficiency for TSCH networks. Recently proposed autonomous scheduling schemes provide flexible timeslot scheduling based on the routing topology, but do not take into account the network traffic and packet forwarding delays. In this paper, we propose an autonomous scheduling scheme for convergecast in TSCH networks with RPL as a routing protocol, named Escalator. Escalator generates a consecutive timeslot schedule along the packet forwarding path to minimize the packet transmission delay. The schedule is generated autonomously by utilizing only the local routing topology information without any additional signaling with other nodes. The generated schedule is guaranteed to be conflict-free, in that all nodes in the network could transmit packets to the sink in every slotframe cycle. We implement Escalator and evaluate its performance with existing autonomous scheduling schemes through a testbed and simulation. Experimental results show that the proposed Escalator has lower end-to-end delay and higher packet delivery ratio compared to the existing schemes regardless of the network topology. PMID:29659508

Escalator: An Autonomous Scheduling Scheme for Convergecast in TSCH.

PubMed

Oh, Sukho; Hwang, DongYeop; Kim, Ki-Hyung; Kim, Kangseok

2018-04-16

Time Slotted Channel Hopping (TSCH) is widely used in the industrial wireless sensor networks due to its high reliability and energy efficiency. Various timeslot and channel scheduling schemes have been proposed for achieving high reliability and energy efficiency for TSCH networks. Recently proposed autonomous scheduling schemes provide flexible timeslot scheduling based on the routing topology, but do not take into account the network traffic and packet forwarding delays. In this paper, we propose an autonomous scheduling scheme for convergecast in TSCH networks with RPL as a routing protocol, named Escalator. Escalator generates a consecutive timeslot schedule along the packet forwarding path to minimize the packet transmission delay. The schedule is generated autonomously by utilizing only the local routing topology information without any additional signaling with other nodes. The generated schedule is guaranteed to be conflict-free, in that all nodes in the network could transmit packets to the sink in every slotframe cycle. We implement Escalator and evaluate its performance with existing autonomous scheduling schemes through a testbed and simulation. Experimental results show that the proposed Escalator has lower end-to-end delay and higher packet delivery ratio compared to the existing schemes regardless of the network topology.

Experiments with a Parallel Multi-Objective Evolutionary Algorithm for Scheduling

NASA Technical Reports Server (NTRS)

Brown, Matthew; Johnston, Mark D.

2013-01-01

Evolutionary multi-objective algorithms have great potential for scheduling in those situations where tradeoffs among competing objectives represent a key requirement. One challenge, however, is runtime performance, as a consequence of evolving not just a single schedule, but an entire population, while attempting to sample the Pareto frontier as accurately and uniformly as possible. The growing availability of multi-core processors in end user workstations, and even laptops, has raised the question of the extent to which such hardware can be used to speed up evolutionary algorithms. In this paper we report on early experiments in parallelizing a Generalized Differential Evolution (GDE) algorithm for scheduling long-range activities on NASA's Deep Space Network. Initial results show that significant speedups can be achieved, but that performance does not necessarily improve as more cores are utilized. We describe our preliminary results and some initial suggestions from parallelizing the GDE algorithm. Directions for future work are outlined.

An adaptive random search for short term generation scheduling with network constraints.

PubMed

Marmolejo, J A; Velasco, Jonás; Selley, Héctor J

2017-01-01

This paper presents an adaptive random search approach to address a short term generation scheduling with network constraints, which determines the startup and shutdown schedules of thermal units over a given planning horizon. In this model, we consider the transmission network through capacity limits and line losses. The mathematical model is stated in the form of a Mixed Integer Non Linear Problem with binary variables. The proposed heuristic is a population-based method that generates a set of new potential solutions via a random search strategy. The random search is based on the Markov Chain Monte Carlo method. The main key of the proposed method is that the noise level of the random search is adaptively controlled in order to exploring and exploiting the entire search space. In order to improve the solutions, we consider coupling a local search into random search process. Several test systems are presented to evaluate the performance of the proposed heuristic. We use a commercial optimizer to compare the quality of the solutions provided by the proposed method. The solution of the proposed algorithm showed a significant reduction in computational effort with respect to the full-scale outer approximation commercial solver. Numerical results show the potential and robustness of our approach.

Tool for Merging Proposals Into DSN Schedules

NASA Technical Reports Server (NTRS)

Khanampornpan, Teerapat; Kwok, John; Call, Jared

2008-01-01

A Practical Extraction and Reporting Language (Perl) script called merge7da has been developed to facilitate determination, by a project scheduler in NASA's Deep Space Network, of whether a proposal for use of the DSN could create a conflict with the current DSN schedule. Prior to the development of merge7da, there was no way to quickly identify potential schedule conflicts: it was necessary to submit a proposal and wait a day or two for a response from a DSN scheduling facility. By using merge7da to detect and eliminate potential schedule conflicts before submitting a proposal, a project scheduler saves time and gains assurance that the proposal will probably be accepted. merge7da accepts two input files, one of which contains the current DSN schedule and is in a DSN-standard format called '7da'. The other input file contains the proposal and is in another DSN-standard format called 'C1/C2'. merge7da processes the two input files to produce a merged 7da-format output file that represents the DSN schedule as it would be if the proposal were to be adopted. This 7da output file can be loaded into various DSN scheduling software tools now in use.

KSC-2009-6830

NASA Image and Video Library

2009-12-15

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., technicians from NASA's Goddard Space Flight Center rotate the bagged Solar Dynamics Observatory, or SDO, secured to a Ransome table, into a vertical position. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. For information on SDO, visit http://www.nasa.gov/sdo. Photo credit: NASA/Troy Cryder

KSC-2009-6839

NASA Image and Video Library

2009-12-15

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., technicians from NASA's Goddard Space Flight Center secure the bagged Solar Dynamics Observatory, or SDO, onto a dolly for further processing. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. For information on SDO, visit http://www.nasa.gov/sdo. Photo credit: NASA/Troy Cryder

Active Control of Wind-Tunnel Model Aeroelastic Response Using Neural Networks

NASA Technical Reports Server (NTRS)

Scott, Robert C.

2000-01-01

NASA Langley Research Center, Hampton, VA 23681 Under a joint research and development effort conducted by the National Aeronautics and Space Administration and The Boeing Company (formerly McDonnell Douglas) three neural-network based control systems were developed and tested. The control systems were experimentally evaluated using a transonic wind-tunnel model in the Langley Transonic Dynamics Tunnel. One system used a neural network to schedule flutter suppression control laws, another employed a neural network in a predictive control scheme, and the third employed a neural network in an inverse model control scheme. All three of these control schemes successfully suppressed flutter to or near the limits of the testing apparatus, and represent the first experimental applications of neural networks to flutter suppression. This paper will summarize the findings of this project.

Interference Cognizant Network Scheduling

NASA Technical Reports Server (NTRS)

Hall, Brendan (Inventor); Bonk, Ted (Inventor); DeLay, Benjamin F. (Inventor); Varadarajan, Srivatsan (Inventor); Smithgall, William Todd (Inventor)

2017-01-01

Systems and methods for interference cognizant network scheduling are provided. In certain embodiments, a method of scheduling communications in a network comprises identifying a bin of a global timeline for scheduling an unscheduled virtual link, wherein a bin is a segment of the timeline; identifying a pre-scheduled virtual link in the bin; and determining if the pre-scheduled and unscheduled virtual links share a port. In certain embodiments, if the unscheduled and pre-scheduled virtual links don't share a port, scheduling transmission of the unscheduled virtual link to overlap with the scheduled transmission of the pre-scheduled virtual link; and if the unscheduled and pre-scheduled virtual links share a port: determining a start time delay for the unscheduled virtual link based on the port; and scheduling transmission of the unscheduled virtual link in the bin based on the start time delay to overlap part of the scheduled transmission of the pre-scheduled virtual link.

Co-scheduling of network resource provisioning and host-to-host bandwidth reservation on high-performance network and storage systems

DOEpatents

Yu, Dantong; Katramatos, Dimitrios; Sim, Alexander; Shoshani, Arie

2014-04-22

A cross-domain network resource reservation scheduler configured to schedule a path from at least one end-site includes a management plane device configured to monitor and provide information representing at least one of functionality, performance, faults, and fault recovery associated with a network resource; a control plane device configured to at least one of schedule the network resource, provision local area network quality of service, provision local area network bandwidth, and provision wide area network bandwidth; and a service plane device configured to interface with the control plane device to reserve the network resource based on a reservation request and the information from the management plane device. Corresponding methods and computer-readable medium are also disclosed.

A Multi-Verse Optimizer with Levy Flights for Numerical Optimization and Its Application in Test Scheduling for Network-on-Chip.

PubMed

Hu, Cong; Li, Zhi; Zhou, Tian; Zhu, Aijun; Xu, Chuanpei

2016-01-01

We propose a new meta-heuristic algorithm named Levy flights multi-verse optimizer (LFMVO), which incorporates Levy flights into multi-verse optimizer (MVO) algorithm to solve numerical and engineering optimization problems. The Original MVO easily falls into stagnation when wormholes stochastically re-span a number of universes (solutions) around the best universe achieved over the course of iterations. Since Levy flights are superior in exploring unknown, large-scale search space, they are integrated into the previous best universe to force MVO out of stagnation. We test this method on three sets of 23 well-known benchmark test functions and an NP complete problem of test scheduling for Network-on-Chip (NoC). Experimental results prove that the proposed LFMVO is more competitive than its peers in both the quality of the resulting solutions and convergence speed.

A Multi-Verse Optimizer with Levy Flights for Numerical Optimization and Its Application in Test Scheduling for Network-on-Chip

PubMed Central

Hu, Cong; Li, Zhi; Zhou, Tian; Zhu, Aijun; Xu, Chuanpei

2016-01-01

We propose a new meta-heuristic algorithm named Levy flights multi-verse optimizer (LFMVO), which incorporates Levy flights into multi-verse optimizer (MVO) algorithm to solve numerical and engineering optimization problems. The Original MVO easily falls into stagnation when wormholes stochastically re-span a number of universes (solutions) around the best universe achieved over the course of iterations. Since Levy flights are superior in exploring unknown, large-scale search space, they are integrated into the previous best universe to force MVO out of stagnation. We test this method on three sets of 23 well-known benchmark test functions and an NP complete problem of test scheduling for Network-on-Chip (NoC). Experimental results prove that the proposed LFMVO is more competitive than its peers in both the quality of the resulting solutions and convergence speed. PMID:27926946

A model for managing edge effects in harvest scheduling using spatial optimization

Treesearch

Kai L. Ross; Sándor F. Tóth

2016-01-01

Actively managed forest stands can create new forest edges. If left unchecked over time and across space, forest operations such as clear-cuts can create complex networks of forest edges. Newly created edges alter the landscape and can affect many environmental factors. These altered environmental factors have a variety of impacts on forest growth and structure and can...

Hybrid scheduling mechanisms for Next-generation Passive Optical Networks based on network coding

NASA Astrophysics Data System (ADS)

Zhao, Jijun; Bai, Wei; Liu, Xin; Feng, Nan; Maier, Martin

2014-10-01

Network coding (NC) integrated into Passive Optical Networks (PONs) is regarded as a promising solution to achieve higher throughput and energy efficiency. To efficiently support multimedia traffic under this new transmission mode, novel NC-based hybrid scheduling mechanisms for Next-generation PONs (NG-PONs) including energy management, time slot management, resource allocation, and Quality-of-Service (QoS) scheduling are proposed in this paper. First, we design an energy-saving scheme that is based on Bidirectional Centric Scheduling (BCS) to reduce the energy consumption of both the Optical Line Terminal (OLT) and Optical Network Units (ONUs). Next, we propose an intra-ONU scheduling and an inter-ONU scheduling scheme, which takes NC into account to support service differentiation and QoS assurance. The presented simulation results show that BCS achieves higher energy efficiency under low traffic loads, clearly outperforming the alternative NC-based Upstream Centric Scheduling (UCS) scheme. Furthermore, BCS is shown to provide better QoS assurance.

40 CFR 58.12 - Operating schedules.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.12 Operating schedules. State and local... part. Area-specific PAMS operating schedules must be included as part of the PAMS network description... remains once every six days. No less frequently than as part of each 5-year network assessment, the most...

40 CFR 58.12 - Operating schedules.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.12 Operating schedules. State and local... part. Area-specific PAMS operating schedules must be included as part of the PAMS network description... remains once every six days. No less frequently than as part of each 5-year network assessment, the most...

KSC-2009-6236

NASA Image and Video Library

2009-11-09

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., the Solar Dynamics Observatory, or SDO, with its solar arrays deployed, is ready to receive signal commands to test the release mechanism sequence for the arrays. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. Photo credit: NASA/Jack Pfaller

KSC-2009-5305

NASA Image and Video Library

2009-10-01

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., workers secure the Solar Dynamics Observatory, or SDO, onto a work stand during preparations for propulsion system testing and leak checks on the spacecraft. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. Photo credit: NASA/Amanda Diller

The Space Grant Internet Telescope Network (SGITN): The beginning

NASA Astrophysics Data System (ADS)

Hardersen, Paul S.

2007-12-01

The Space Grant Internet Telescope Network (SGITN) is envisioned as a national network of Internet-controllable astronomical observatories that will be available to university students and faculty residing in participating NASA Space Grant states. Our goal is to provide no-cost astronomical resources to non-AURA colleges and universities, with the hope of expanding student and faculty access to astronomical facilities and to encourage students to pursue research careers in astronomy and planetary science. The Network has been created and is managed by the North Dakota Space Grant Consortium, which is a part of the NASA Space Grant College and Fellowship Program. The SGITN began operations on August 1, 2007, with small observatories in North and South Dakota. Telescope apertures range from 10- to 26-inches and support astrometric and photometric research opportunities. Most observatories are controlled via ACP Observatory Control Software, but use of this particular software is not required. However, all participating observatories must be remotely controllable. The UND Observatory, west of Grand Forks, ND, will ultimately contribute four observatories to this Network, while South Dakota is contributing the Badlands Observatory. A new observatory in Utah will join the Network by 12/31/2007. Our goal is to attract > 15 observatories to this Network in the coming years, which will support a large user base and enable unique projects, such as near-Earth asteroid distance determinations. Current users access Network facilities via the SGITN home page at http://sgitn.space.edu. Eligible students and faculty submit observing proposals for consideration and should contribute to a scientifically valid and justifiable research project. All of the necessary forms and information are on the web site and are downloadable as PDF documents. Qualified users work with the SGITN to schedule observing dates and times. Users are encouraged to post their results on the SGITN web site.

Dynamic Hierarchical Sleep Scheduling for Wireless Ad-Hoc Sensor Networks

PubMed Central

Wen, Chih-Yu; Chen, Ying-Chih

2009-01-01

This paper presents two scheduling management schemes for wireless sensor networks, which manage the sensors by utilizing the hierarchical network structure and allocate network resources efficiently. A local criterion is used to simultaneously establish the sensing coverage and connectivity such that dynamic cluster-based sleep scheduling can be achieved. The proposed schemes are simulated and analyzed to abstract the network behaviors in a number of settings. The experimental results show that the proposed algorithms provide efficient network power control and can achieve high scalability in wireless sensor networks. PMID:22412343

Dynamic hierarchical sleep scheduling for wireless ad-hoc sensor networks.

PubMed

Wen, Chih-Yu; Chen, Ying-Chih

2009-01-01

This paper presents two scheduling management schemes for wireless sensor networks, which manage the sensors by utilizing the hierarchical network structure and allocate network resources efficiently. A local criterion is used to simultaneously establish the sensing coverage and connectivity such that dynamic cluster-based sleep scheduling can be achieved. The proposed schemes are simulated and analyzed to abstract the network behaviors in a number of settings. The experimental results show that the proposed algorithms provide efficient network power control and can achieve high scalability in wireless sensor networks.

A mission planning concept and mission planning system for future manned space missions

NASA Technical Reports Server (NTRS)

Wickler, Martin

1994-01-01

The international character of future manned space missions will compel the involvement of several international space agencies in mission planning tasks. Additionally, the community of users requires a higher degree of freedom for experiment planning. Both of these problems can be solved by a decentralized mission planning concept using the so-called 'envelope method,' by which resources are allocated to users by distributing resource profiles ('envelopes') which define resource availabilities at specified times. The users are essentially free to plan their activities independently of each other, provided that they stay within their envelopes. The new developments were aimed at refining the existing vague envelope concept into a practical method for decentralized planning. Selected critical functions were exercised by planning an example, founded on experience acquired by the MSCC during the Spacelab missions D-1 and D-2. The main activity regarding future mission planning tasks was to improve the existing MSCC mission planning system, using new techniques. An electronic interface was developed to collect all formalized user inputs more effectively, along with an 'envelope generator' for generation and manipulation of the resource envelopes. The existing scheduler and its data base were successfully replaced by an artificial intelligence scheduler. This scheduler is not only capable of handling resource envelopes, but also uses a new technology based on neuronal networks. Therefore, it is very well suited to solve the future scheduling problems more efficiently. This prototype mission planning system was used to gain new practical experience with decentralized mission planning, using the envelope method. In future steps, software tools will be optimized, and all data management planning activities will be embedded into the scheduler.

32 GHz Celestial Reference Frame Survey for Dec < -45 deg.

NASA Astrophysics Data System (ADS)

Horiuchi, Shinji; Phillips, Chris; Stevens, Jamie; Jacobs, Christopher; Sotuela, Ioana; Garcia miro, Cristina

2014-04-01

(We resubmit this proposal to extend from the previous semester. The 24 hour blocks for ATCA and Mopra were granted in May 2012 but canceled because fringe test before the scheduled experiment failed although fringes were detected between Mopra and Tidbinbilla. During the last scheduled LBA session for this project we discovered ATCA/Mopra had an issue with frequency standard, which has now been resolved.) We propose to conduct a LBA survey of compact radio sources at 32 GHz near the south pole region. This is the first attempt to fill the gap in the existing 32 GHz catalogue establish by NASA Deep Space Network toward completing the full sky celestial reference frame at 32 GHz. The catalogue will be used for future spacecraft navigation by NASA and other space agencies as well as for radio astronomical observations with southern radio telescope arrays such as ATCA and LBA.

Using Common Graphics Paradigms Implemented in a Java Applet to Represent Complex Scheduling Requirements

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth

1997-01-01

The experiments planned for the International Space Station promise to be complex, lengthy and diverse. The scarcity of the space station resources will cause significant competition for resources between experiments. The scheduling job facing the Space Station mission planning software requires a concise and comprehensive description of the experiments' requirements (to ensure a valid schedule) and a good description of the experiments' flexibility (to effectively utilize available resources). In addition, the continuous operation of the station, the wide geographic dispersion of station users, and the budgetary pressure to reduce operations manpower make a low-cost solution mandatory. A graphical representation of the scheduling requirements for station payloads implemented via an Internet-based application promises to be an elegant solution that addresses all of these issues. The graphical representation of experiment requirements permits a station user to describe his experiment by defining "activities" and "sequences of activities". Activities define the resource requirements (with alternatives) and other quantitative constraints of tasks to be performed. Activities definitions use an "outline" graphics paradigm. Sequences define the time relationships between activities. Sequences may also define time relationships with activities of other payloads or space station systems. Sequences of activities are described by a "network" graphics paradigm. The bulk of this paper will describe the graphical approach to representing requirements and provide examples that show the ease and clarity with which complex requirements can be represented. A Java applet, to run in a web browser, is being developed to support the graphical representation of payload scheduling requirements. Implementing the entry and editing of requirements via the web solves the problems introduced by the geographic dispersion of users. Reducing manpower is accomplished by developing a concise representation which eliminates the misunderstanding possible with verbose representations and which captures the complete requirements and flexibility of the experiments.

Software cost/resource modeling: Deep space network software cost estimation model

NASA Technical Reports Server (NTRS)

Tausworthe, R. J.

1980-01-01

A parametric software cost estimation model prepared for JPL deep space network (DSN) data systems implementation tasks is presented. The resource estimation model incorporates principles and data from a number of existing models, such as those of the General Research Corporation, Doty Associates, IBM (Walston-Felix), Rome Air Force Development Center, University of Maryland, and Rayleigh-Norden-Putnam. The model calibrates task magnitude and difficulty, development environment, and software technology effects through prompted responses to a set of approximately 50 questions. Parameters in the model are adjusted to fit JPL software lifecycle statistics. The estimation model output scales a standard DSN work breakdown structure skeleton, which is then input to a PERT/CPM system, producing a detailed schedule and resource budget for the project being planned.

Investigation of bus transit schedule behavior modeling using advanced techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalaputapu, R.; Demetsky, M.J.

This research focused on investigating the application of artificial neural networks (ANN) and the Box-Jenkins technique for developing and testing schedule behavior models using data obtained for a test route from Tidewater Regional Transit`s AVL system. The three ANN architectures investigated were: Feedforward Network, Elman Network and Jordan Network. In addition, five different model structures were investigated. The time-series methodology was adopted for developing the schedule behavior models. Finally, the role of a schedule behavior model within the framework of an intelligent transit management system is defined and the potential utility of the schedule behavior model is discussed using anmore » example application.« less

Integrating Space Communication Network Capabilities via Web Portal Technologies

NASA Technical Reports Server (NTRS)

Johnston, Mark D.; Lee, Carlyn-Ann; Lau, Chi-Wung; Cheung, Kar-Ming; Levesque, Michael; Carruth, Butch; Coffman, Adam; Wallace, Mike

2014-01-01

We have developed a service portal prototype as part of an investigation into the feasibility of using Java portlet technology as a means of providing integrated access to NASA communications network services. Portal servers provide an attractive platform for this role due to the various built-in collaboration applications they can provide, combined with the possibility to develop custom inter-operating portlets to extent their functionality while preserving common presentation and behavior. This paper describes various options for integration of network services related to planning and scheduling, and results based on use of a popular open-source portal framework. Plans are underway to develop an operational SCaN Service Portal, building on the experiences reported here.

Scheduling with Automatic Resolution of Conflicts

NASA Technical Reports Server (NTRS)

Clement, Bradley; Schaffer, Steve

2006-01-01

DSN Requirement Scheduler is a computer program that automatically schedules, reschedules, and resolves conflicts for allocations of resources of NASA s Deep Space Network (DSN) on the basis of ever-changing project requirements for DSN services. As used here, resources signifies, primarily, DSN antennas, ancillary equipment, and times during which they are available. Examples of project-required DSN services include arraying, segmentation, very-long-baseline interferometry, and multiple spacecraft per aperture. Requirements can include periodic reservations of specific or optional resources during specific time intervals or within ranges specified in terms of starting times and durations. This program is built on the Automated Scheduling and Planning Environment (ASPEN) software system (aspects of which have been described in previous NASA Tech Briefs articles), with customization to reflect requirements and constraints involved in allocation of DSN resources. Unlike prior DSN-resource- scheduling programs that make single passes through the requirements and require human intervention to resolve conflicts, this program makes repeated passes in a continuing search for all possible allocations, provides a best-effort solution at any time, and presents alternative solutions among which users can choose.

Next Generation NASA Initiative for Space Geodesy

NASA Technical Reports Server (NTRS)

Merkowitz, S. M.; Desai, S.; Gross, R. S.; Hilliard, L.; Lemoine, F. G.; Long, J. L.; Ma, C.; McGarry J. F.; Murphy, D.; Noll, C. E.;

On the number of different dynamics in Boolean networks with deterministic update schedules.

PubMed

Aracena, J; Demongeot, J; Fanchon, E; Montalva, M

2013-04-01

Deterministic Boolean networks are a type of discrete dynamical systems widely used in the modeling of genetic networks. The dynamics of such systems is characterized by the local activation functions and the update schedule, i.e., the order in which the nodes are updated. In this paper, we address the problem of knowing the different dynamics of a Boolean network when the update schedule is changed. We begin by proving that the problem of the existence of a pair of update schedules with different dynamics is NP-complete. However, we show that certain structural properties of the interaction diagraph are sufficient for guaranteeing distinct dynamics of a network. In [1] the authors define equivalence classes which have the property that all the update schedules of a given class yield the same dynamics. In order to determine the dynamics associated to a network, we develop an algorithm to efficiently enumerate the above equivalence classes by selecting a representative update schedule for each class with a minimum number of blocks. Finally, we run this algorithm on the well known Arabidopsis thaliana network to determine the full spectrum of its different dynamics. Copyright © 2013 Elsevier Inc. All rights reserved.

Essential SpaceWire Hardware Capabilities for a Robust Network

NASA Technical Reports Server (NTRS)

Birmingham, Michael; Krimchansky, Alexander; Anderson, William; Lombardi, Matthew

2016-01-01

The Geostationary Operational Environmental Satellite R-Series Program (GOES-R) mission is a joint program between National Oceanic & Atmospheric Administration (NOAA) and National Aeronautics & Space Administration (NASA) Goddard Space Flight Center (GSFC). GOES-R project selected SpaceWire as the best solution to satisfy the desire for simple and flexible instrument to spacecraft command and telemetry communications. GOES-R development and integration is complete and the observatory is scheduled for launch October 2016. The spacecraft design was required to support redundant SpaceWire links for each instrument side, as well as to route the fewest number of connections through a Slip Ring Assembly necessary to support Solar pointing instruments. The final design utilized two different router designs. The SpaceWire standard alone does not ensure the most practical or reliable network. On GOES-R a few key hardware capabilities were identified that merit serious consideration for future designs. Primarily these capabilities address persistent port stalls and the prevention of receive buffer overflows. Workarounds were necessary to overcome shortcomings that could be avoided in future designs if they utilize the capabilities, discussed in this paper, above and beyond the requirements of the SpaceWire standard.

Spiking neural network simulation: memory-optimal synaptic event scheduling.

PubMed

Stewart, Robert D; Gurney, Kevin N

2011-06-01

Spiking neural network simulations incorporating variable transmission delays require synaptic events to be scheduled prior to delivery. Conventional methods have memory requirements that scale with the total number of synapses in a network. We introduce novel scheduling algorithms for both discrete and continuous event delivery, where the memory requirement scales instead with the number of neurons. Superior algorithmic performance is demonstrated using large-scale, benchmarking network simulations.

An approach to rescheduling activities based on determination of priority and disruptivity

NASA Technical Reports Server (NTRS)

Sponsler, Jeffrey L.; Johnston, Mark D.

1990-01-01

A constraint-based scheduling system called SPIKE is being used to create long term schedules for the Hubble Space Telescope. Feedback for the spacecraft or from other ground support systems may invalidate some scheduling decisions and those activities concerned must be reconsidered. A function rescheduling priority is defined which for a given activity performs a heuristic analysis and produces a relative numerical value which is used to rank all such entities in the order that they should be rescheduled. A function disruptivity is also defined that is used to place a relative numeric value on how much a pre-existing schedule would be changed in order to reschedule an activity. Using these functions, two algorithms (a stochastic neural network approach and an exhaustive search approach) are proposed to find the best place to reschedule an activity. Prototypes were implemented and preliminary testing reveals that the exhaustive technique produces only marginally better results at much greater computational cost.

Capacity Model and Constraints Analysis for Integrated Remote Wireless Sensor and Satellite Network in Emergency Scenarios

PubMed Central

Zhang, Wei; Zhang, Gengxin; Dong, Feihong; Xie, Zhidong; Bian, Dongming

2015-01-01

This article investigates the capacity problem of an integrated remote wireless sensor and satellite network (IWSSN) in emergency scenarios. We formulate a general model to evaluate the remote sensor and satellite network capacity. Compared to most existing works for ground networks, the proposed model is time varying and space oriented. To capture the characteristics of a practical network, we sift through major capacity-impacting constraints and analyze the influence of these constraints. Specifically, we combine the geometric satellite orbit model and satellite tool kit (STK) engineering software to quantify the trends of the capacity constraints. Our objective in analyzing these trends is to provide insights and design guidelines for optimizing the integrated remote wireless sensor and satellite network schedules. Simulation results validate the theoretical analysis of capacity trends and show the optimization opportunities of the IWSSN. PMID:26593919

Capacity Model and Constraints Analysis for Integrated Remote Wireless Sensor and Satellite Network in Emergency Scenarios.

PubMed

Zhang, Wei; Zhang, Gengxin; Dong, Feihong; Xie, Zhidong; Bian, Dongming

2015-11-17

This article investigates the capacity problem of an integrated remote wireless sensor and satellite network (IWSSN) in emergency scenarios. We formulate a general model to evaluate the remote sensor and satellite network capacity. Compared to most existing works for ground networks, the proposed model is time varying and space oriented. To capture the characteristics of a practical network, we sift through major capacity-impacting constraints and analyze the influence of these constraints. Specifically, we combine the geometric satellite orbit model and satellite tool kit (STK) engineering software to quantify the trends of the capacity constraints. Our objective in analyzing these trends is to provide insights and design guidelines for optimizing the integrated remote wireless sensor and satellite network schedules. Simulation results validate the theoretical analysis of capacity trends and show the optimization opportunities of the IWSSN.

Improved Scheduling Mechanisms for Synchronous Information and Energy Transmission.

PubMed

Qin, Danyang; Yang, Songxiang; Zhang, Yan; Ma, Jingya; Ding, Qun

2017-06-09

Wireless energy collecting technology can effectively reduce the network time overhead and prolong the wireless sensor network (WSN) lifetime. However, the traditional energy collecting technology cannot achieve the balance between ergodic channel capacity and average collected energy. In order to solve the problem of the network transmission efficiency and the limited energy of wireless devices, three improved scheduling mechanisms are proposed: improved signal noise ratio (SNR) scheduling mechanism (IS2M), improved N-SNR scheduling mechanism (INS2M) and an improved Equal Throughput scheduling mechanism (IETSM) for different channel conditions to improve the whole network performance. Meanwhile, the average collected energy of single users and the ergodic channel capacity of three scheduling mechanisms can be obtained through the order statistical theory in Rayleig, Ricean, Nakagami- m and Weibull fading channels. It is concluded that the proposed scheduling mechanisms can achieve better balance between energy collection and data transmission, so as to provide a new solution to realize synchronous information and energy transmission for WSNs.

Improved Scheduling Mechanisms for Synchronous Information and Energy Transmission

PubMed Central

Qin, Danyang; Yang, Songxiang; Zhang, Yan; Ma, Jingya; Ding, Qun

2017-01-01

Wireless energy collecting technology can effectively reduce the network time overhead and prolong the wireless sensor network (WSN) lifetime. However, the traditional energy collecting technology cannot achieve the balance between ergodic channel capacity and average collected energy. In order to solve the problem of the network transmission efficiency and the limited energy of wireless devices, three improved scheduling mechanisms are proposed: improved signal noise ratio (SNR) scheduling mechanism (IS2M), improved N-SNR scheduling mechanism (INS2M) and an improved Equal Throughput scheduling mechanism (IETSM) for different channel conditions to improve the whole network performance. Meanwhile, the average collected energy of single users and the ergodic channel capacity of three scheduling mechanisms can be obtained through the order statistical theory in Rayleig, Ricean, Nakagami-m and Weibull fading channels. It is concluded that the proposed scheduling mechanisms can achieve better balance between energy collection and data transmission, so as to provide a new solution to realize synchronous information and energy transmission for WSNs. PMID:28598395

Some key considerations in evolving a computer system and software engineering support environment for the space station program

NASA Technical Reports Server (NTRS)

Mckay, C. W.; Bown, R. L.

1985-01-01

The space station data management system involves networks of computing resources that must work cooperatively and reliably over an indefinite life span. This program requires a long schedule of modular growth and an even longer period of maintenance and operation. The development and operation of space station computing resources will involve a spectrum of systems and software life cycle activities distributed across a variety of hosts, an integration, verification, and validation host with test bed, and distributed targets. The requirement for the early establishment and use of an apporopriate Computer Systems and Software Engineering Support Environment is identified. This environment will support the Research and Development Productivity challenges presented by the space station computing system.

KSC-04PD-0148

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Astronaut Tim Kopra (second from right) talks with workers in the Space Station Processing Facility about the Intravehicular Activity (IVA) constraints testing on the Italian-built Node 2, a future element of the International Space Station. . The second of three Station connecting modules, the Node 2 attaches to the end of the U.S. Lab and provides attach locations for several other elements. Kopra is currently assigned technical duties in the Space Station Branch of the Astronaut Office, where his primary focus involves the testing of crew interfaces for two future ISS modules as well as the implementation of support computers and operational Local Area Network on ISS. Node 2 is scheduled to launch on mission STS-120, Station assembly flight 10A.

Intelligent Resource Management for Local Area Networks: Approach and Evolution

NASA Technical Reports Server (NTRS)

Meike, Roger

1988-01-01

The Data Management System network is a complex and important part of manned space platforms. Its efficient operation is vital to crew, subsystems and experiments. AI is being considered to aid in the initial design of the network and to augment the management of its operation. The Intelligent Resource Management for Local Area Networks (IRMA-LAN) project is concerned with the application of AI techniques to network configuration and management. A network simulation was constructed employing real time process scheduling for realistic loads, and utilizing the IEEE 802.4 token passing scheme. This simulation is an integral part of the construction of the IRMA-LAN system. From it, a causal model is being constructed for use in prediction and deep reasoning about the system configuration. An AI network design advisor is being added to help in the design of an efficient network. The AI portion of the system is planned to evolve into a dynamic network management aid. The approach, the integrated simulation, project evolution, and some initial results are described.

Design and implementation of priority and time-window based traffic scheduling and routing-spectrum allocation mechanism in elastic optical networks

NASA Astrophysics Data System (ADS)

Wang, Honghuan; Xing, Fangyuan; Yin, Hongxi; Zhao, Nan; Lian, Bizhan

2016-02-01

With the explosive growth of network services, the reasonable traffic scheduling and efficient configuration of network resources have an important significance to increase the efficiency of the network. In this paper, an adaptive traffic scheduling policy based on the priority and time window is proposed and the performance of this algorithm is evaluated in terms of scheduling ratio. The routing and spectrum allocation are achieved by using the Floyd shortest path algorithm and establishing a node spectrum resource allocation model based on greedy algorithm, which is proposed by us. The fairness index is introduced to improve the capability of spectrum configuration. The results show that the designed traffic scheduling strategy can be applied to networks with multicast and broadcast functionalities, and makes them get real-time and efficient response. The scheme of node spectrum configuration improves the frequency resource utilization and gives play to the efficiency of the network.

Distributed intelligent scheduling of FMS

NASA Astrophysics Data System (ADS)

Wu, Zuobao; Cheng, Yaodong; Pan, Xiaohong

1995-08-01

In this paper, a distributed scheduling approach of a flexible manufacturing system (FMS) is presented. A new class of Petri nets called networked time Petri nets (NTPN) for system modeling of networking environment is proposed. The distributed intelligent scheduling is implemented by three schedulers which combine NTPN models with expert system techniques. The simulation results are shown.

KSC-98pc484

NASA Image and Video Library

1998-04-15

KENNEDY SPACE CENTER, FLA. -- With the Rotating Service Structure (RSS) rolled back, at left, the Space Shuttle Columbia is nearly ready for launch of STS-90. Rollback of the RSS is a major preflight milestone, typically occurring during the T-11-hour hold on L-1 (the day before launch). The scheduled launch of Columbia on Apr. 16 from Launch Pad 39B was postponed 24 hours due to difficulty with network signal processor No. 2 on the orbiter. This device formats data and voice communications between the ground and the Space Shuttle. The unit, which is located in the orbiter's mid-deck, will be removed and replaced. Prior to launch, one of the final steps will be to load the external tank with approximately 500,000 gallons of liquid hydrogen and liquid oxygen for fueling the orbiters three main engines. Tanking had not yet begun when the launch scheduled for Apr. 16 was scrubbed. STS-90 is slated to be the launch of Neurolab, a nearly 17-day mission to examine the effects of spaceflight on the brain, spinal cord, peripheral nerves and sensory organs in the human body

KSC-98pc483

NASA Image and Video Library

1998-04-15

KENNEDY SPACE CENTER, FLA. -- With the Rotating Service Structure (RSS) rolled back, at left, the Space Shuttle Columbia is nearly ready for launch of STS-90. Rollback of the RSS is a major preflight milestone, typically occurring during the T-11-hour hold on L-1 (the day before launch). The scheduled launch of Columbia on Apr. 16 from Launch Pad 39B was postponed 24 hours due to difficulty with network signal processor No. 2 on the orbiter. This device formats data and voice communications between the ground and the Space Shuttle. The unit, which is located in the orbiter's mid-deck, will be removed and replaced. Prior to launch, one of the final steps will be to load the external tank with approximately 500,000 gallons of liquid hydrogen and liquid oxygen for fueling the orbiters three main engines. Tanking had not yet begun when the launch scheduled for Apr. 16 was scrubbed. STS-90 is slated to be the launch of Neurolab, a nearly 17-day mission to examine the effects of spaceflight on the brain, spinal cord, peripheral nerves and sensory organs in the human body

Delay/Disruption Tolerance Networking (DTN) Implementation and Utilization Options on the International Space Station

NASA Technical Reports Server (NTRS)

Holbrook, Mark; Pitts, Robert Lee; Gifford, Kevin K.; Jenkins, Andrew; Kuzminsky, Sebastian

2010-01-01

The International Space Station (ISS) is in an operational configuration and nearing final assembly. With its maturity and diverse payloads onboard, the opportunity exists to extend the orbital lab into a facility to exercise and demonstrate Delay/Disruption Tolerant Networking (DTN). DTN is an end-to-end network service providing communications through environments characterized by intermittent connectivity, variable delays, high bit error rates, asymmetric links and simplex links. The DTN protocols, also known as bundle protocols, provide a store-and-forward capability to accommodate end-to-end network services. Key capabilities of the bundling protocols include: the Ability to cope with intermittent connectivity, the Ability to take advantage of scheduled and opportunistic connectivity (in addition to always up connectivity), Custody Transfer, and end-to-end security. Colorado University at Boulder and the Huntsville Operational Support Center (HOSC) have been developing a DTN capability utilizing the Commercial Generic Bioprocessing Apparatus (CGBA) payload resources onboard the ISS, at the Boulder Payload Operations Center (POC) and at the HOSC. The DTN capability is in parallel with and is designed to augment current capabilities. The architecture consists of DTN endpoint nodes on the ISS and at the Boulder POC, and a DTN node at the HOSC. The DTN network is composed of two implementations; the Interplanetary Overlay Network (ION) and the open source DTN2 implementation. This paper presents the architecture, implementation, and lessons learned. By being able to handle the types of environments described above, the DTN technology will be instrumental in extending networks into deep space to support future missions to other planets and other solar system points of interest. Thus, this paper also discusses how this technology will be applicable to these types of deep space exploration missions.

New Scheduling Algorithms for Agile All-Photonic Networks

NASA Astrophysics Data System (ADS)

Mehri, Mohammad Saleh; Ghaffarpour Rahbar, Akbar

2017-12-01

An optical overlaid star network is a class of agile all-photonic networks that consists of one or more core node(s) at the center of the star network and a number of edge nodes around the core node. In this architecture, a core node may use a scheduling algorithm for transmission of traffic through the network. A core node is responsible for scheduling optical packets that arrive from edge nodes and switching them toward their destinations. Nowadays, most edge nodes use virtual output queue (VOQ) architecture for buffering client packets to achieve high throughput. This paper presents two efficient scheduling algorithms called discretionary iterative matching (DIM) and adaptive DIM. These schedulers find maximum matching in a small number of iterations and provide high throughput and incur low delay. The number of arbiters in these schedulers and the number of messages exchanged between inputs and outputs of a core node are reduced. We show that DIM and adaptive DIM can provide better performance in comparison with iterative round-robin matching with SLIP (iSLIP). SLIP means the act of sliding for a short distance to select one of the requested connections based on the scheduling algorithm.

Systematic Hybrid Network Scheduling for Multiple Traffic Classes with Host Timing and Phase Constraints

NASA Technical Reports Server (NTRS)

Hall, Brendan (Inventor); Bonk, Ted (Inventor); Varadarajan, Srivatsan (Inventor); Smithgall, William Todd (Inventor); DeLay, Benjamin F. (Inventor)

2017-01-01

Systems and methods for systematic hybrid network scheduling for multiple traffic classes with host timing and phase constraints are provided. In certain embodiments, a method of scheduling communications in a network comprises scheduling transmission of virtual links pertaining to a first traffic class on a global schedule to coordinate transmission of the virtual links pertaining to the first traffic class across all transmitting end stations on the global schedule; and scheduling transmission of each virtual link pertaining to a second traffic class on a local schedule of the respective transmitting end station from which each respective virtual link pertaining to the second traffic class is transmitted such that transmission of each virtual link pertaining to the second traffic class is coordinated only at the respective end station from which each respective virtual link pertaining to the second traffic class is transmitted.

Space station common module power system network topology and hardware development

NASA Technical Reports Server (NTRS)

Landis, D. M.

1985-01-01

Candidate power system newtork topologies for the space station common module are defined and developed and the necessary hardware for test and evaluation is provided. Martin Marietta's approach to performing the proposed program is presented. Performance of the tasks described will assure systematic development and evaluation of program results, and will provide the necessary management tools, visibility, and control techniques for performance assessment. The plan is submitted in accordance with the data requirements given and includes a comprehensive task logic flow diagram, time phased manpower requirements, a program milestone schedule, and detailed descriptions of each program task.

KSC-2009-6485

NASA Image and Video Library

2009-11-19

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., spacecraft technicians secure one of the solar panels on the Solar Dynamics Observatory, or SDO, to the side of the spacecraft for launch. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. For information on SDO, visit http://www.nasa.gov/sdo. Photo credit: NASA/Jack Pfaller

KSC-2009-6831

NASA Image and Video Library

2009-12-15

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., the Solar Dynamics Observatory, or SDO, secured to a Ransome table, has been bagged and is rotated into a vertical position. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. For information on SDO, visit http://www.nasa.gov/sdo. Photo credit: NASA/Troy Cryder

KSC-2009-6829

NASA Image and Video Library

2009-12-15

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., the Solar Dynamics Observatory, or SDO, secured to a Ransome table, has been bagged and is being rotated from a horizontal to a vertical position. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. For information on SDO, visit http://www.nasa.gov/sdo. Photo credit: NASA/Troy Cryder

Space applications of artificial intelligence; Proceedings of the Annual Goddard Conference, Greenbelt, MD, May 16, 17, 1989

NASA Technical Reports Server (NTRS)

Rash, James L. (Editor); Dent, Carolyn P. (Editor)

1989-01-01

Theoretical and implementation aspects of AI systems for space applications are discussed in reviews and reports. Sections are devoted to planning and scheduling, fault isolation and diagnosis, data management, modeling and simulation, and development tools and methods. Particular attention is given to a situated reasoning architecture for space repair and replace tasks, parallel plan execution with self-processing networks, the electrical diagnostics expert system for Spacelab life-sciences experiments, diagnostic tolerance for missing sensor data, the integration of perception and reasoning in fast neural modules, a connectionist model for dynamic control, and applications of fuzzy sets to the development of rule-based expert systems.

Parallel plan execution with self-processing networks

NASA Technical Reports Server (NTRS)

Dautrechy, C. Lynne; Reggia, James A.

1989-01-01

A critical issue for space operations is how to develop and apply advanced automation techniques to reduce the cost and complexity of working in space. In this context, it is important to examine how recent advances in self-processing networks can be applied for planning and scheduling tasks. For this reason, the feasibility of applying self-processing network models to a variety of planning and control problems relevant to spacecraft activities is being explored. Goals are to demonstrate that self-processing methods are applicable to these problems, and that MIRRORS/II, a general purpose software environment for implementing self-processing models, is sufficiently robust to support development of a wide range of application prototypes. Using MIRRORS/II and marker passing modelling techniques, a model of the execution of a Spaceworld plan was implemented. This is a simplified model of the Voyager spacecraft which photographed Jupiter, Saturn, and their satellites. It is shown that plan execution, a task usually solved using traditional artificial intelligence (AI) techniques, can be accomplished using a self-processing network. The fact that self-processing networks were applied to other space-related tasks, in addition to the one discussed here, demonstrates the general applicability of this approach to planning and control problems relevant to spacecraft activities. It is also demonstrated that MIRRORS/II is a powerful environment for the development and evaluation of self-processing systems.

Integrated RF/Optical Interplanetary Networking Preliminary Explorations and Empirical Results

NASA Technical Reports Server (NTRS)

Raible, Daniel E.; Hylton, Alan G.

2012-01-01

Over the last decade interplanetary telecommunication capabilities have been significantly expanded--specifically in support of the Mars exploration rover and lander missions. NASA is continuing to drive advances in new, high payoff optical communications technologies to enhance the network to Gbps performance from Mars, and the transition from technology demonstration to operational system is examined through a hybrid RF/optical approach. Such a system combines the best features of RF and optical communications considering availability and performance to realize a dual band trunk line operating within characteristic constraints. Disconnection due to planetary obscuration and solar conjunction, link delays, timing, ground terminal mission congestion and scheduling policy along with space and atmospheric weather disruptions all imply the need for network protocol solutions to ultimately manage the physical layer in a transparent manner to the end user. Delay Tolerant Networking (DTN) is an approach under evaluation which addresses these challenges. A multi-hop multi-path hybrid RF and optical test bed has been constructed to emulate the integrated deep space network and to support protocol and hardware refinement. Initial experimental results characterize several of these challenges and evaluate the effectiveness of DTN as a solution to mitigate them.

Space station program phase B definition: Nuclear reactor-powered space station cost and schedules

NASA Technical Reports Server (NTRS)

1971-01-01

Tabulated data are presented on the costs, schedules, and technical characteristics for the space station phases C and D program. The work breakdown structure, schedule data, program ground rules, program costs, cost-estimating rationale, funding schedules, and supporting data are included.

Development of a Deterministic Ethernet Building blocks for Space Applications

NASA Astrophysics Data System (ADS)

Fidi, C.; Jakovljevic, Mirko

2015-09-01

The benefits of using commercially based networking standards and protocols have been widely discussed and are expected to include reduction in overall mission cost, shortened integration and test (I&T) schedules, increased operations flexibility, and hardware and software upgradeability/scalability with developments ongoing in the commercial world. The deterministic Ethernet technology TTEthernet [1] diploid on the NASA Orion spacecraft has demonstrated the use of the TTEthernet technology for a safety critical human space flight application during the Exploration Flight Test 1 (EFT-1). The TTEthernet technology used within the NASA Orion program has been matured for the use within this mission but did not lead to a broader use in space applications or an international space standard. Therefore TTTech has developed a new version which allows to scale the technology for different applications not only the high end missions allowing to decrease the size of the building blocks leading to a reduction of size weight and power enabling the use in smaller applications. TTTech is currently developing a full space products offering for its TTEthernet technology to allow the use in different space applications not restricted to launchers and human spaceflight. A broad space market assessment and the current ESA TRP7594 lead to the development of a space grade TTEthernet controller ASIC based on the ESA qualified Atmel AT1C8RHA95 process [2]. In this paper we will describe our current TTEthernet controller development towards a space qualified network component allowing future spacecrafts to operate in significant radiation environments while using a single onboard network for reliable commanding and data transfer.

HURON (HUman and Robotic Optimization Network) Multi-Agent Temporal Activity Planner/Scheduler

NASA Technical Reports Server (NTRS)

Hua, Hook; Mrozinski, Joseph J.; Elfes, Alberto; Adumitroaie, Virgil; Shelton, Kacie E.; Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

2012-01-01

HURON solves the problem of how to optimize a plan and schedule for assigning multiple agents to a temporal sequence of actions (e.g., science tasks). Developed as a generic planning and scheduling tool, HURON has been used to optimize space mission surface operations. The tool has also been used to analyze lunar architectures for a variety of surface operational scenarios in order to maximize return on investment and productivity. These scenarios include numerous science activities performed by a diverse set of agents: humans, teleoperated rovers, and autonomous rovers. Once given a set of agents, activities, resources, resource constraints, temporal constraints, and de pendencies, HURON computes an optimal schedule that meets a specified goal (e.g., maximum productivity or minimum time), subject to the constraints. HURON performs planning and scheduling optimization as a graph search in state-space with forward progression. Each node in the graph contains a state instance. Starting with the initial node, a graph is automatically constructed with new successive nodes of each new state to explore. The optimization uses a set of pre-conditions and post-conditions to create the children states. The Python language was adopted to not only enable more agile development, but to also allow the domain experts to easily define their optimization models. A graphical user interface was also developed to facilitate real-time search information feedback and interaction by the operator in the search optimization process. The HURON package has many potential uses in the fields of Operations Research and Management Science where this technology applies to many commercial domains requiring optimization to reduce costs. For example, optimizing a fleet of transportation truck routes, aircraft flight scheduling, and other route-planning scenarios involving multiple agent task optimization would all benefit by using HURON.

Optimal Learning Paths in Information Networks

PubMed Central

Rodi, G. C.; Loreto, V.; Servedio, V. D. P.; Tria, F.

2015-01-01

Each sphere of knowledge and information could be depicted as a complex mesh of correlated items. By properly exploiting these connections, innovative and more efficient navigation strategies could be defined, possibly leading to a faster learning process and an enduring retention of information. In this work we investigate how the topological structure embedding the items to be learned can affect the efficiency of the learning dynamics. To this end we introduce a general class of algorithms that simulate the exploration of knowledge/information networks standing on well-established findings on educational scheduling, namely the spacing and lag effects. While constructing their learning schedules, individuals move along connections, periodically revisiting some concepts, and sometimes jumping on very distant ones. In order to investigate the effect of networked information structures on the proposed learning dynamics we focused both on synthetic and real-world graphs such as subsections of Wikipedia and word-association graphs. We highlight the existence of optimal topological structures for the simulated learning dynamics whose efficiency is affected by the balance between hubs and the least connected items. Interestingly, the real-world graphs we considered lead naturally to almost optimal learning performances. PMID:26030508

Constraint-based integration of planning and scheduling for space-based observatory management

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Smith, Steven F.

1994-01-01

Progress toward the development of effective, practical solutions to space-based observatory scheduling problems within the HSTS scheduling framework is reported. HSTS was developed and originally applied in the context of the Hubble Space Telescope (HST) short-term observation scheduling problem. The work was motivated by the limitations of the current solution and, more generally, by the insufficiency of classical planning and scheduling approaches in this problem context. HSTS has subsequently been used to develop improved heuristic solution techniques in related scheduling domains and is currently being applied to develop a scheduling tool for the upcoming Submillimeter Wave Astronomy Satellite (SWAS) mission. The salient architectural characteristics of HSTS and their relationship to previous scheduling and AI planning research are summarized. Then, some key problem decomposition techniques underlying the integrated planning and scheduling approach to the HST problem are described; research results indicate that these techniques provide leverage in solving space-based observatory scheduling problems. Finally, more recently developed constraint-posting scheduling procedures and the current SWAS application focus are summarized.

Covariance and Uncertainty Realism in Space Surveillance and Tracking

DTIC Science & Technology

2016-06-27

control infrastructure , there are also further complications in the implementation of centralized scheduling of some of the SSN sensors due to their...this data however. 5.8.3 Long-Term Long-term developments of JSpOC processing, net-centric interfaces and sensor backends will provide the...with particle filters for mobile sensor network control. In Proceedings of the 45th IEEE Conference on Decision and Control, pages 1019–1024, December

Service-Oriented Node Scheduling Scheme for Wireless Sensor Networks Using Markov Random Field Model

PubMed Central

Cheng, Hongju; Su, Zhihuang; Lloret, Jaime; Chen, Guolong

2014-01-01

Future wireless sensor networks are expected to provide various sensing services and energy efficiency is one of the most important criterions. The node scheduling strategy aims to increase network lifetime by selecting a set of sensor nodes to provide the required sensing services in a periodic manner. In this paper, we are concerned with the service-oriented node scheduling problem to provide multiple sensing services while maximizing the network lifetime. We firstly introduce how to model the data correlation for different services by using Markov Random Field (MRF) model. Secondly, we formulate the service-oriented node scheduling issue into three different problems, namely, the multi-service data denoising problem which aims at minimizing the noise level of sensed data, the representative node selection problem concerning with selecting a number of active nodes while determining the services they provide, and the multi-service node scheduling problem which aims at maximizing the network lifetime. Thirdly, we propose a Multi-service Data Denoising (MDD) algorithm, a novel multi-service Representative node Selection and service Determination (RSD) algorithm, and a novel MRF-based Multi-service Node Scheduling (MMNS) scheme to solve the above three problems respectively. Finally, extensive experiments demonstrate that the proposed scheme efficiently extends the network lifetime. PMID:25384005

Simulation Modeling and Performance Evaluation of Space Networks

NASA Technical Reports Server (NTRS)

Jennings, Esther H.; Segui, John

2006-01-01

In space exploration missions, the coordinated use of spacecraft as communication relays increases the efficiency of the endeavors. To conduct trade-off studies of the performance and resource usage of different communication protocols and network designs, JPL designed a comprehensive extendable tool, the Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE). The design and development of MACHETE began in 2000 and is constantly evolving. Currently, MACHETE contains Consultative Committee for Space Data Systems (CCSDS) protocol standards such as Proximity-1, Advanced Orbiting Systems (AOS), Packet Telemetry/Telecommand, Space Communications Protocol Specification (SCPS), and the CCSDS File Delivery Protocol (CFDP). MACHETE uses the Aerospace Corporation s Satellite Orbital Analysis Program (SOAP) to generate the orbital geometry information and contact opportunities. Matlab scripts provide the link characteristics. At the core of MACHETE is a discrete event simulator, QualNet. Delay Tolerant Networking (DTN) is an end-to-end architecture providing communication in and/or through highly stressed networking environments. Stressed networking environments include those with intermittent connectivity, large and/or variable delays, and high bit error rates. To provide its services, the DTN protocols reside at the application layer of the constituent internets, forming a store-and-forward overlay network. The key capabilities of the bundling protocols include custody-based reliability, ability to cope with intermittent connectivity, ability to take advantage of scheduled and opportunistic connectivity, and late binding of names to addresses. In this presentation, we report on the addition of MACHETE models needed to support DTN, namely: the Bundle Protocol (BP) model. To illustrate the use of MACHETE with the additional DTN model, we provide an example simulation to benchmark its performance. We demonstrate the use of the DTN protocol and discuss statistics gathered concerning the total time needed to simulate numerous bundle transmissions

Expert systems and advanced automation for space missions operations

NASA Technical Reports Server (NTRS)

Durrani, Sajjad H.; Perkins, Dorothy C.; Carlton, P. Douglas

1990-01-01

Increased complexity of space missions during the 1980s led to the introduction of expert systems and advanced automation techniques in mission operations. This paper describes several technologies in operational use or under development at the National Aeronautics and Space Administration's Goddard Space Flight Center. Several expert systems are described that diagnose faults, analyze spacecraft operations and onboard subsystem performance (in conjunction with neural networks), and perform data quality and data accounting functions. The design of customized user interfaces is discussed, with examples of their application to space missions. Displays, which allow mission operators to see the spacecraft position, orientation, and configuration under a variety of operating conditions, are described. Automated systems for scheduling are discussed, and a testbed that allows tests and demonstrations of the associated architectures, interface protocols, and operations concepts is described. Lessons learned are summarized.

KSC-2013-4396

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at Cape Canaveral Air Force Station's Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-4394

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at Cape Canaveral Air Force Station's Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-4428

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, a Centaur second stage is positioned atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-3790

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Centaur upper stage that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4395

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at Cape Canaveral Air Force Station's Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-3792

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Centaur upper stage that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4429

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, a Centaur second stage is positioned atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

Introduction of human papillomavirus (HPV) vaccination into national immunisation schedules in Europe: Results of the VENICE 2007 survey.

PubMed

King, L A; Lévy-Bruhl, D; O'Flanagan, D; Bacci, S; Lopalco, P L; Kudjawu, Y; Salmaso, S

2008-08-14

The European Union Member States are simultaneously considering introducing HPV vaccination into their national immunisation schedules. The Vaccine European New Integrated Collaboration Effort (VENICE) project aims to develop a collaborative European vaccination network. A survey was undertaken to describe the decision status and the decision-making process regarding the potential introduction of human papillomavirus (HPV) vaccination in to their national immunisation schedules. A web-based questionnaire was developed and completed online in 2007 by 28 countries participating in VENICE. As of 31 October 2007,five countries had decided to introduce HPV vaccination into the national immunisation schedule, while another seven had started the decision-making process with a recommendation favouring introduction. Varying target populations were selected by the five countries which had introduced the vaccination. Half of the surveyed countries had undertaken at least one ad hoc study to support the decision-making process. According to an update of the decision-status from January 2008, the number of countries which had made a decision or recommendation changed to 10 and 5 respectively. This survey demonstrates the rapidly evolving nature of HPV vaccine introduction in Europe and the existence of expertise and experience among EU Member States. The VENICE network is capable of following this process and supporting countries in making vaccine introduction decisions. A VENICE collaborative web-space is being developed as a European resource for the decision-making process for vaccine introduction.

NASA scheduling technologies

NASA Technical Reports Server (NTRS)

Adair, Jerry R.

1994-01-01

This paper is a consolidated report on ten major planning and scheduling systems that have been developed by the National Aeronautics and Space Administration (NASA). A description of each system, its components, and how it could be potentially used in private industry is provided in this paper. The planning and scheduling technology represented by the systems ranges from activity based scheduling employing artificial intelligence (AI) techniques to constraint based, iterative repair scheduling. The space related application domains in which the systems have been deployed vary from Space Shuttle monitoring during launch countdown to long term Hubble Space Telescope (HST) scheduling. This paper also describes any correlation that may exist between the work done on different planning and scheduling systems. Finally, this paper documents the lessons learned from the work and research performed in planning and scheduling technology and describes the areas where future work will be conducted.

Chip-set for quality of service support in passive optical networks

NASA Astrophysics Data System (ADS)

Ringoot, Edwin; Hoebeke, Rudy; Slabbinck, B. Hans; Verhaert, Michel

1998-10-01

In this paper the design of a chip-set for QoS provisioning in ATM-based Passive Optical Networks is discussed. The implementation of a general-purpose switch chip on the Optical Network Unit is presented, with focus on the design of the cell scheduling and buffer management logic. The cell scheduling logic supports `colored' grants, priority jumping and weighted round-robin scheduling. The switch chip offers powerful buffer management capabilities enabling the efficient support of GFR and UBR services. Multicast forwarding is also supported. In addition, the architecture of a MAC controller chip developed for a SuperPON access network is introduced. In particular, the permit scheduling logic and its implementation on the Optical Line Termination will be discussed. The chip-set enables the efficient support of services with different service requirements on the SuperPON. The permit scheduling logic built into the MAC controller chip in combination with the cell scheduling and buffer management capabilities of the switch chip can be used by network operators to offer guaranteed service performance to delay sensitive services, and to efficiently and fairly distribute any spare capacity to delay insensitive services.

Investigations into Generalization of Constraint-Based Scheduling Theories with Applications to Space Telescope Observation Scheduling

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Smith, Steven S.

1996-01-01

This final report summarizes research performed under NASA contract NCC 2-531 toward generalization of constraint-based scheduling theories and techniques for application to space telescope observation scheduling problems. Our work into theories and techniques for solution of this class of problems has led to the development of the Heuristic Scheduling Testbed System (HSTS), a software system for integrated planning and scheduling. Within HSTS, planning and scheduling are treated as two complementary aspects of the more general process of constructing a feasible set of behaviors of a target system. We have validated the HSTS approach by applying it to the generation of observation schedules for the Hubble Space Telescope. This report summarizes the HSTS framework and its application to the Hubble Space Telescope domain. First, the HSTS software architecture is described, indicating (1) how the structure and dynamics of a system is modeled in HSTS, (2) how schedules are represented at multiple levels of abstraction, and (3) the problem solving machinery that is provided. Next, the specific scheduler developed within this software architecture for detailed management of Hubble Space Telescope operations is presented. Finally, experimental performance results are given that confirm the utility and practicality of the approach.

Scheduling work zones in multi-modal networks phase 1: scheduling work zones in transportation service networks.

DOT National Transportation Integrated Search

2016-06-01

The purpose of this project is to study the optimal scheduling of work zones so that they have minimum negative impact (e.g., travel delay, gas consumption, accidents, etc.) on transport service vehicle flows. In this project, a mixed integer linear ...

Advanced Communication and Networking Technologies for Mars Exploration

NASA Technical Reports Server (NTRS)

Bhasin, Kul; Hayden, Jeff; Agre, Jonathan R.; Clare, Loren P.; Yan, Tsun-Yee

2001-01-01

Next-generation Mars communications networks will provide communications and navigation services to a wide variety of Mars science vehicles including: spacecraft that are arriving at Mars, spacecraft that are entering and descending in the Mars atmosphere, scientific orbiter spacecraft, spacecraft that return Mars samples to Earth, landers, rovers, aerobots, airplanes, and sensing pods. In the current architecture plans, the communication services will be provided using capabilities deployed on the science vehicles as well as dedicated communication satellites that will together make up the Mars network. This network will evolve as additional vehicles arrive, depart or end their useful missions. Cost savings and increased reliability will result from the ability to share communication services between missions. This paper discusses the basic architecture that is needed to support the Mars Communications Network part of NASA's Space Science Enterprise (SSE) communications architecture. The network may use various networking technologies such as those employed in the terrestrial Internet, as well as special purpose deep-space protocols to move data and commands autonomously between vehicles, at disparate Mars vicinity sites (on the surface or in near-Mars space) and between Mars vehicles and earthbound users. The architecture of the spacecraft on-board local communications is being reconsidered in light of these new networking requirements. The trend towards increasingly autonomous operation of the spacecraft is aimed at reducing the dependence on resource scheduling provided by Earth-based operators and increasing system fault tolerance. However, these benefits will result in increased communication and software development requirements. As a result, the envisioned Mars communications infrastructure requires both hardware and protocol technology advancements. This paper will describe a number of the critical technology needs and some of the ongoing research activities.

An Optimal Schedule for Urban Road Network Repair Based on the Greedy Algorithm

PubMed Central

Lu, Guangquan; Xiong, Ying; Wang, Yunpeng

2016-01-01

The schedule of urban road network recovery caused by rainstorms, snow, and other bad weather conditions, traffic incidents, and other daily events is essential. However, limited studies have been conducted to investigate this problem. We fill this research gap by proposing an optimal schedule for urban road network repair with limited repair resources based on the greedy algorithm. Critical links will be given priority in repair according to the basic concept of the greedy algorithm. In this study, the link whose restoration produces the ratio of the system-wide travel time of the current network to the worst network is the minimum. We define such a link as the critical link for the current network. We will re-evaluate the importance of damaged links after each repair process is completed. That is, the critical link ranking will be changed along with the repair process because of the interaction among links. We repair the most critical link for the specific network state based on the greedy algorithm to obtain the optimal schedule. The algorithm can still quickly obtain an optimal schedule even if the scale of the road network is large because the greedy algorithm can reduce computational complexity. We prove that the problem can obtain the optimal solution using the greedy algorithm in theory. The algorithm is also demonstrated in the Sioux Falls network. The problem discussed in this paper is highly significant in dealing with urban road network restoration. PMID:27768732

October Spacewalks Aboard the Space Station on This Week @NASA – October 13, 2017

NASA Image and Video Library

2017-10-13

The Oct. 10th spacewalk outside the International Space Station was the second in less than a week by NASA’s Randy Bresnik and Mark Vande Hei – and one of three U.S. spacewalks planned for October. The astronauts lubricated the new latching end effector they installed on the Canadarm2 robotic arm on Oct. 5. They also replaced a faulty camera system and completed several other tasks. Joe Acaba will join Bresnik for the next spacewalk – currently scheduled for Oct. 20. Also, California Wildfires Seen from Space, NASA Pinpoints Cause of Earth’s Record CO2 Levels, Send Your Name to Mars, Celebrating the First Piloted Supersonic Flight, and Potential Asteroid Warning Network Tested!

The Temporal Configuration of Airline Networks

NASA Technical Reports Server (NTRS)

Burghouwt, Guillaume; deWit, Jaap

2003-01-01

The deregulation of US aviation in 1978 resulted in the reconfiguration of airline networks into hub-and-spoke systems, spatially concentrated around a small number of central airports or 'hubs' through which an airline operates a number of daily waves of flights. A hub-and-spoke network requires a concentration of traffic in both space and time. In contrast to the U.S. airlines, European airlines had entered the phase of spatial network concentration long before deregulation. Bilateral negotiation of traffic fights between governments forced European airlines to focus their networks spatially on small number of 'national' airports. In general, these star-shaped networks were not coordinated in time. Transfer opportunities at central airports were mostly created 'by accident'. With the deregulation of the EU air transport market from 1988 on, a second phase of airline network concentration started. European airlines concentrated their networks in time by adopting or intensifying wave-system structures in their flight schedules. Temporal concentration may increase the competitive position of the network in a deregulated market because of certain cost and demand advantages.

KSC-2009-6479

NASA Image and Video Library

2009-11-19

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., spacecraft technicians secure the high-gain communications antenna on the Solar Dynamics Observatory, or SDO, against the spacecraft following testing to verify the spacecraft's readiness for launch. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. Liftoff on an Atlas V rocket is scheduled for Feb. 3, 2010. For information on SDO, visit http://www.nasa.gov/sdo. Photo credit: NASA/Jack Pfaller

Decomposability and scalability in space-based observatory scheduling

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Smith, Stephen F.

1992-01-01

In this paper, we discuss issues of problem and model decomposition within the HSTS scheduling framework. HSTS was developed and originally applied in the context of the Hubble Space Telescope (HST) scheduling problem, motivated by the limitations of the current solution and, more generally, the insufficiency of classical planning and scheduling approaches in this problem context. We first summarize the salient architectural characteristics of HSTS and their relationship to previous scheduling and AI planning research. Then, we describe some key problem decomposition techniques supported by HSTS and underlying our integrated planning and scheduling approach, and we discuss the leverage they provide in solving space-based observatory scheduling problems.

Taming Wild Horses: The Need for Virtual Time-based Scheduling of VMs in Network Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoginath, Srikanth B; Perumalla, Kalyan S; Henz, Brian J

2012-01-01

The next generation of scalable network simulators employ virtual machines (VMs) to act as high-fidelity models of traffic producer/consumer nodes in simulated networks. However, network simulations could be inaccurate if VMs are not scheduled according to virtual time, especially when many VMs are hosted per simulator core in a multi-core simulator environment. Since VMs are by default free-running, on the outset, it is not clear if, and to what extent, their untamed execution affects the results in simulated scenarios. Here, we provide the first quantitative basis for establishing the need for generalized virtual time scheduling of VMs in network simulators,more » based on an actual prototyped implementations. To exercise breadth, our system is tested with multiple disparate applications: (a) a set of message passing parallel programs, (b) a computer worm propagation phenomenon, and (c) a mobile ad-hoc wireless network simulation. We define and use error metrics and benchmarks in scaled tests to empirically report the poor match of traditional, fairness-based VM scheduling to VM-based network simulation, and also clearly show the better performance of our simulation-specific scheduler, with up to 64 VMs hosted on a 12-core simulator node.« less

Integrated scheduling and resource management. [for Space Station Information System

NASA Technical Reports Server (NTRS)

Ward, M. T.

1987-01-01

This paper examines the problem of integrated scheduling during the Space Station era. Scheduling for Space Station entails coordinating the support of many distributed users who are sharing common resources and pursuing individual and sometimes conflicting objectives. This paper compares the scheduling integration problems of current missions with those anticipated for the Space Station era. It examines the facilities and the proposed operations environment for Space Station. It concludes that the pattern of interdependecies among the users and facilities, which are the source of the integration problem is well structured, allowing a dividing of the larger problem into smaller problems. It proposes an architecture to support integrated scheduling by scheduling efficiently at local facilities as a function of dependencies with other facilities of the program. A prototype is described that is being developed to demonstrate this integration concept.

Protocols for distributive scheduling

NASA Technical Reports Server (NTRS)

Richards, Stephen F.; Fox, Barry

1993-01-01

The increasing complexity of space operations and the inclusion of interorganizational and international groups in the planning and control of space missions lead to requirements for greater communication, coordination, and cooperation among mission schedulers. These schedulers must jointly allocate scarce shared resources among the various operational and mission oriented activities while adhering to all constraints. This scheduling environment is complicated by such factors as the presence of varying perspectives and conflicting objectives among the schedulers, the need for different schedulers to work in parallel, and limited communication among schedulers. Smooth interaction among schedulers requires the use of protocols that govern such issues as resource sharing, authority to update the schedule, and communication of updates. This paper addresses the development and characteristics of such protocols and their use in a distributed scheduling environment that incorporates computer-aided scheduling tools. An example problem is drawn from the domain of space shuttle mission planning.

Distributed project scheduling at NASA: Requirements for manual protocols and computer-based support

NASA Technical Reports Server (NTRS)

Richards, Stephen F.

1992-01-01

The increasing complexity of space operations and the inclusion of interorganizational and international groups in the planning and control of space missions lead to requirements for greater communication, coordination, and cooperation among mission schedulers. These schedulers must jointly allocate scarce shared resources among the various operational and mission oriented activities while adhering to all constraints. This scheduling environment is complicated by such factors as the presence of varying perspectives and conflicting objectives among the schedulers, the need for different schedulers to work in parallel, and limited communication among schedulers. Smooth interaction among schedulers requires the use of protocols that govern such issues as resource sharing, authority to update the schedule, and communication of updates. This paper addresses the development and characteristics of such protocols and their use in a distributed scheduling environment that incorporates computer-aided scheduling tools. An example problem is drawn from the domain of Space Shuttle mission planning.

Stochastic Control and Numerical Methods with Applications to Communications. Game Theoretic/Subsolution to Importance Sampling for Rare Event Simulation

DTIC Science & Technology

2008-11-01

support to the value of the approach. 9. Scheduling and Control of Mobile Communications Networks with Randomly Time Varying Channels by Stability ...biological systems . Many examples arise in communications and queueing, due to the finite speed of signal transmission, the nonnegligible time required...without delays, the system state takes values in a subset of some finite -dimensional Euclidean space, and the control is a functional of the current

Enabling parallel simulation of large-scale HPC network systems

DOE PAGES

Mubarak, Misbah; Carothers, Christopher D.; Ross, Robert B.; ...

2016-04-07

Here, with the increasing complexity of today’s high-performance computing (HPC) architectures, simulation has become an indispensable tool for exploring the design space of HPC systems—in particular, networks. In order to make effective design decisions, simulations of these systems must possess the following properties: (1) have high accuracy and fidelity, (2) produce results in a timely manner, and (3) be able to analyze a broad range of network workloads. Most state-of-the-art HPC network simulation frameworks, however, are constrained in one or more of these areas. In this work, we present a simulation framework for modeling two important classes of networks usedmore » in today’s IBM and Cray supercomputers: torus and dragonfly networks. We use the Co-Design of Multi-layer Exascale Storage Architecture (CODES) simulation framework to simulate these network topologies at a flit-level detail using the Rensselaer Optimistic Simulation System (ROSS) for parallel discrete-event simulation. Our simulation framework meets all the requirements of a practical network simulation and can assist network designers in design space exploration. First, it uses validated and detailed flit-level network models to provide an accurate and high-fidelity network simulation. Second, instead of relying on serial time-stepped or traditional conservative discrete-event simulations that limit simulation scalability and efficiency, we use the optimistic event-scheduling capability of ROSS to achieve efficient and scalable HPC network simulations on today’s high-performance cluster systems. Third, our models give network designers a choice in simulating a broad range of network workloads, including HPC application workloads using detailed network traces, an ability that is rarely offered in parallel with high-fidelity network simulations« less

Enabling parallel simulation of large-scale HPC network systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mubarak, Misbah; Carothers, Christopher D.; Ross, Robert B.

Here, with the increasing complexity of today’s high-performance computing (HPC) architectures, simulation has become an indispensable tool for exploring the design space of HPC systems—in particular, networks. In order to make effective design decisions, simulations of these systems must possess the following properties: (1) have high accuracy and fidelity, (2) produce results in a timely manner, and (3) be able to analyze a broad range of network workloads. Most state-of-the-art HPC network simulation frameworks, however, are constrained in one or more of these areas. In this work, we present a simulation framework for modeling two important classes of networks usedmore » in today’s IBM and Cray supercomputers: torus and dragonfly networks. We use the Co-Design of Multi-layer Exascale Storage Architecture (CODES) simulation framework to simulate these network topologies at a flit-level detail using the Rensselaer Optimistic Simulation System (ROSS) for parallel discrete-event simulation. Our simulation framework meets all the requirements of a practical network simulation and can assist network designers in design space exploration. First, it uses validated and detailed flit-level network models to provide an accurate and high-fidelity network simulation. Second, instead of relying on serial time-stepped or traditional conservative discrete-event simulations that limit simulation scalability and efficiency, we use the optimistic event-scheduling capability of ROSS to achieve efficient and scalable HPC network simulations on today’s high-performance cluster systems. Third, our models give network designers a choice in simulating a broad range of network workloads, including HPC application workloads using detailed network traces, an ability that is rarely offered in parallel with high-fidelity network simulations« less

QoS support over ultrafast TDM optical networks

NASA Astrophysics Data System (ADS)

Narvaez, Paolo; Siu, Kai-Yeung; Finn, Steven G.

1999-08-01

HLAN is a promising architecture to realize Tb/s access networks based on ultra-fast optical TDM technologies. This paper presents new research results on efficient algorithms for the support of quality of service over the HLAN network architecture. In particular, we propose a new scheduling algorithm that emulates fair queuing in a distributed manner for bandwidth allocation purpose. The proposed scheduler collects information on the queue of each host on the network and then instructs each host how much data to send. Our new scheduling algorithm ensures full bandwidth utilization, while guaranteeing fairness among all hosts.

Architectural impact of FDDI network on scheduling hard real-time traffic

NASA Technical Reports Server (NTRS)

Agrawal, Gopal; Chen, Baio; Zhao, Wei; Davari, Sadegh

1991-01-01

The architectural impact on guaranteeing synchronous message deadlines in FDDI (Fiber Distributed Data Interface) token ring networks is examined. The FDDI network does not have facility to support (global) priority arbitration which is a useful facility for scheduling hard real time activities. As a result, it was found that the worst case utilization of synchronous traffic in an FDDI network can be far less than that in a centralized single processor system. Nevertheless, it is proposed and analyzed that a scheduling method can guarantee deadlines of synchronous messages having traffic utilization up to 33 pct., the highest to date.

Enhanced Software for Scheduling Space-Shuttle Processing

NASA Technical Reports Server (NTRS)

Barretta, Joseph A.; Johnson, Earl P.; Bierman, Rocky R.; Blanco, Juan; Boaz, Kathleen; Stotz, Lisa A.; Clark, Michael; Lebovitz, George; Lotti, Kenneth J.; Moody, James M.;

TDRS-L Spacecraft Transported from Astrotech to SLC

NASA Image and Video Library

2014-01-13

CAPE CANAVERAL, Fla. – Encapsulated in its payload fairing, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft is transported along the Saturn Causeway at the Kennedy Space Center on its way to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Dimitri Gerondidakis

Cooperation and information replication in wireless networks.

PubMed

Poularakis, Konstantinos; Tassiulas, Leandros

2016-03-06

A significant portion of today's network traffic is due to recurring downloads of a few popular contents. It has been observed that replicating the latter in caches installed at network edges-close to users-can drastically reduce network bandwidth usage and improve content access delay. Such caching architectures are gaining increasing interest in recent years as a way of dealing with the explosive traffic growth, fuelled further by the downward slope in storage space price. In this work, we provide an overview of caching with a particular emphasis on emerging network architectures that enable caching at the radio access network. In this context, novel challenges arise due to the broadcast nature of the wireless medium, which allows simultaneously serving multiple users tuned into a multicast stream, and the mobility of the users who may be frequently handed off from one cell tower to another. Existing results indicate that caching at the wireless edge has a great potential in removing bottlenecks on the wired backbone networks. Taking into consideration the schedule of multicast service and mobility profiles is crucial to extract maximum benefit in network performance. © 2016 The Author(s).

Can SNMP be Used to Create a Silent SS in an 802.16 Implementation

DTIC Science & Technology

2008-09-01

wireless transmissions by using the Simple Network Management Protocol (SNMP). SNMP is a networking protocol that can be used by network ...802.16 as a unique networking technology. In a more familiar wireless networking environment like Wi-Fi, there is no central scheduler for access to...much a concern due to the scheduling algorithm , this power saving method provides good transmission security as a

KSC-2013-4406

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4431

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, a United Launch Alliance Atlas V rocket, with its Centaur second stage atop, stands in the Vertical Integration Facility as preparations continue for lift off of the Tracking and Data Relay Satellite, or TDRS-L. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4407

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4415

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket positioned in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4418

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – The United Launch Alliance Centaur second stage that will help boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4421

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, a technician supports preparations for lifting the Centaur second stage of the United Launch Alliance rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4427

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, a Centaur second stage is lifted for stacking atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-3791

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4410

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4398

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Vertical Integration Facility at Launch Complex 41, a crane is positioned to support stacking of the United Launch Alliance Atlas V rocket that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4400

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, engineers and technicians prepare the United Launch Alliance Atlas V rocket for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4389

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-3793

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4423

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, engineers and technicians support lifting a Centaur second stage for stacking atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4417

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – The United Launch Alliance Centaur second stage that will help boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4411

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4425

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, engineers and technicians support lifting a Centaur second stage for stacking atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-3789

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Centaur upper stage that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-3794

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4393

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-4408

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, a technician supports lifting of a United Launch Alliance Atlas V rocket in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4403

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4416

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket positioned in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-3784

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4405

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4422

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, engineers and technicians support preparations for lifting the Centaur second stage of the United Launch Alliance rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4430

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, engineers and technicians inspect a Centaur second stage that was just stacked atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4392

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-4401

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, engineers and technicians prepare the United Launch Alliance Atlas V rocket for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-3788

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4414

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4424

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, engineers and technicians support lifting a Centaur second stage for stacking atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4419

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – The United Launch Alliance Centaur second stage that will help boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-3787

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4390

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being prepared for transport from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-4399

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, engineers and technicians prepare the United Launch Alliance Atlas V rocket for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4409

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, the first stage of the United Launch Alliance Atlas V rocket is lifted for stacking in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4426

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Launch Complex 41, a Centaur second stage is lifted for stacking atop a United Launch Alliance Atlas V rocket that will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-3785

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

KSC-2013-4391

NASA Image and Video Library

2013-12-12

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V first stage booster that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported from the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station to Launch Complex 41. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Kim Shiflett

KSC-2013-4397

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Vertical Integration Facility at Launch Complex 41, a crane is positioned to support stacking of the United Launch Alliance Atlas V rocket that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

Distributed Estimation, Coding, and Scheduling in Wireless Visual Sensor Networks

ERIC Educational Resources Information Center

Yu, Chao

2013-01-01

In this thesis, we consider estimation, coding, and sensor scheduling for energy efficient operation of wireless visual sensor networks (VSN), which consist of battery-powered wireless sensors with sensing (imaging), computation, and communication capabilities. The competing requirements for applications of these wireless sensor networks (WSN)…

Constraint satisfaction adaptive neural network and heuristics combined approaches for generalized job-shop scheduling.

PubMed

Yang, S; Wang, D

2000-01-01

This paper presents a constraint satisfaction adaptive neural network, together with several heuristics, to solve the generalized job-shop scheduling problem, one of NP-complete constraint satisfaction problems. The proposed neural network can be easily constructed and can adaptively adjust its weights of connections and biases of units based on the sequence and resource constraints of the job-shop scheduling problem during its processing. Several heuristics that can be combined with the neural network are also presented. In the combined approaches, the neural network is used to obtain feasible solutions, the heuristic algorithms are used to improve the performance of the neural network and the quality of the obtained solutions. Simulations have shown that the proposed neural network and its combined approaches are efficient with respect to the quality of solutions and the solving speed.

Orbital Express Mission Operations Planning and Resource Management using ASPEN

NASA Technical Reports Server (NTRS)

Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel

2008-01-01

As satellite equipment and mission operations become more costly, the drive to keep working equipment running with less man-power rises.Demonstrating the feasibility of autonomous satellite servicing was the main goal behind the Orbital Express (OE) mission. Planning the satellite mission operations for OE required the ability to create a plan which could be executed autonomously over variable conditions. The Automated-Scheduling and Planning Environment (ASPEN)tool, developed at the Jet Propulsion Laboratory, was used to create the schedule of events in each daily plan for the two satellites of the OE mission. This paper presents an introduction to the ASPEN tool, the constraints of the OE domain, the variable conditions that were presented within the mission, and the solution to operations that ASPEN provided. ASPEN has been used in several other domains, including research rovers, Deep Space Network scheduling research, and in flight operations for the ASE project's EO1 satellite. Related work is discussed, as are the future of ASPEN and the future of autonomous satellite servicing.

Research on a Queue Scheduling Algorithm in Wireless Communications Network

NASA Astrophysics Data System (ADS)

Yang, Wenchuan; Hu, Yuanmei; Zhou, Qiancai

This paper proposes a protocol QS-CT, Queue Scheduling Mechanism based on Multiple Access in Ad hoc net work, which adds queue scheduling mechanism to RTS-CTS-DATA using multiple access protocol. By endowing different queues different scheduling mechanisms, it makes networks access to the channel much more fairly and effectively, and greatly enhances the performance. In order to observe the final performance of the network with QS-CT protocol, we simulate it and compare it with MACA/C-T without QS-CT protocol. Contrast to MACA/C-T, the simulation result shows that QS-CT has greatly improved the throughput, delay, rate of packets' loss and other key indicators.

Planning and Scheduling for Environmental Sensor Networks

NASA Astrophysics Data System (ADS)

Frank, J. D.

2005-12-01

Environmental Sensor Networks are a new way of monitoring the environment. They comprise autonomous sensor nodes in the environment that record real-time data, which is retrieved, analyzed, integrated with other data sets (e.g. satellite images, GIS, process models) and ultimately lead to scientific discoveries. Sensor networks must operate within time and resource constraints. Sensors have limited onboard memory, energy, computational power, communications windows and communications bandwidth. The value of data will depend on when, where and how it was collected, how detailed the data is, how long it takes to integrate the data, and how important the data was to the original scientific question. Planning and scheduling of sensor networks is necessary for effective, safe operations in the face of these constraints. For example, power bus limitations may preclude sensors from simultaneously collecting data and communicating without damaging the sensor; planners and schedulers can ensure these operations are ordered so that they do not happen simultaneously. Planning and scheduling can also ensure best use of the sensor network to maximize the value of collected science data. For example, if data is best recorded using a particular camera angle but it is costly in time and energy to achieve this, planners and schedulers can search for times when time and energy are available to achieve the optimal camera angle. Planning and scheduling can handle uncertainty in the problem specification; planners can be re-run when new information is made available, or can generate plans that include contingencies. For example, if bad weather may prevent the collection of data, a contingent plan can check lighting conditions and turn off data collection to save resources if lighting is not ideal. Both mobile and immobile sensors can benefit from planning and scheduling. For example, data collection on otherwise passive sensors can be halted to preserve limited power and memory resources and to reduce the costs of communication. Planning and scheduling is generally a heavy consumer of time, memory and energy resources. This means careful thought must be given to how much planning and scheduling should be done on the sensors themselves, and how much to do elsewhere. The difficulty of planning and scheduling is exacerbated when reasoning about uncertainty. More time, memory and energy is needed to solve such problems, leading either to more expensive sensors, or suboptimal plans. For example, scientifically interesting events may happen at random times, making it difficult to ensure that sufficient resources are availanble. Since uncertainty is usually lowest in proximity to the sensors themselves, this argues for planning and scheduling onboard the sensors. However, cost minimization dictates sensors be kept as simple as possible, reducing the amount of planning and scheduling they can do themselves. Furthermore, coordinating each sensor's independent plans can be difficult. In the full presentation, we will critically review the planning and scheduling systems used by previously fielded sensor networks. We do so primarily from the perspective of the computational sciences, with a focus on taming computational complexity when operating sensor networks. The case studies are derived from sensor networks based on UAVs, satellites, and planetary rovers. Planning and scheduling considerations include multi-sensor coordination, optimizing science value, onboard power management, onboard memory, planning movement actions to acquire data, and managing communications.These case studies offer lessons for future designs of environmental sensor networks.

Global Precipitation Measurement (GPM) Mission

NASA Image and Video Library

2017-12-08

Gail Skofronick-Jackson, NASA GPM Project Scientist, talks during a science briefing for the launch of the Global Precipitation Measurement (GPM) Core Observatory aboard an H-IIA rocket, Wednesday, Feb. 26, 2014, Tanegashima Space Center, Japan. Launch is scheduled for early in the morning of Feb. 28 Japan time. Once launched, the GPM spacecraft will collect information that unifies data from an international network of existing and future satellites to map global rainfall and snowfall every three hours. Photo Credit: (NASA/Bill Ingalls)

Global Precipitation Measurement (GPM) Mission

NASA Image and Video Library

2017-12-08

Art Azarbarzin, NASA Global Precipitation Measurement (GPM) project manager talks during a technical briefing for the launch of the Global Precipitation Measurement (GPM) Core Observatory aboard an H-IIA rocket, Wednesday, Feb. 26, 2014, Tanegashima Space Center, Japan. Launch is scheduled for early in the morning of Feb. 28 Japan time. Once launched, the GPM spacecraft will collect information that unifies data from an international network of existing and future satellites to map global rainfall and snowfall every three hours. Photo Credit: (NASA/Bill Ingalls)

Accuracy analysis of TDRSS demand forecasts

NASA Technical Reports Server (NTRS)

Stern, Daniel C.; Levine, Allen J.; Pitt, Karl J.

1994-01-01

This paper reviews Space Network (SN) demand forecasting experience over the past 16 years and describes methods used in the forecasts. The paper focuses on the Single Access (SA) service, the most sought-after resource in the Space Network. Of the ten years of actual demand data available, only the last five years (1989 to 1993) were considered predictive due to the extensive impact of the Challenger accident of 1986. NASA's Space Network provides tracking and communications services to user spacecraft such as the Shuttle and the Hubble Space Telescope. Forecasting the customer requirements is essential to planning network resources and to establishing service commitments to future customers. The lead time to procure Tracking and Data Relay Satellites (TDRS's) requires demand forecasts ten years in the future a planning horizon beyond the funding commitments for missions to be supported. The long range forecasts are shown to have had a bias toward underestimation in the 1991 -1992 period. The trend of underestimation can be expected to be replaced by overestimation for a number of years starting with 1998. At that time demand from new missions slated for launch will be larger than the demand from ongoing missions, making the potential for delay the dominant factor. If the new missions appear as scheduled, the forecasts are likely to be moderately underestimated. The SN commitment to meet the negotiated customer's requirements calls for conservatism in the forecasting. Modification of the forecasting procedure to account for a delay bias is, therefore, not advised. Fine tuning the mission model to more accurately reflect the current actual demand is recommended as it may marginally improve the first year forecasting.

Operational VGOS Scheduling

NASA Astrophysics Data System (ADS)

Searle, Anthony; Petrachenko, Bill

2016-12-01

The VLBI Global Observing System (VGOS) has been designed to take advantage of advances in data recording speeds and storage capacity, allowing for smaller and faster antennas, wider bandwidths, and shorter observation durations. Here, schedules for a ``realistic" VGOS network, frequency sequences, and expanded source lists are presented using a new source-based scheduling algorithm. The VGOS aim for continuous observations presents new operational challenges. As the source-based strategy is independent of the observing network, there are operational advantages which allow for more flexible scheduling of continuous VLBI observations. Using VieVS, simulations of several schedules are presented and compared with previous VGOS studies.

Artificial intelligence approaches to astronomical observation scheduling

NASA Technical Reports Server (NTRS)

Johnston, Mark D.; Miller, Glenn

1988-01-01

Automated scheduling will play an increasing role in future ground- and space-based observatory operations. Due to the complexity of the problem, artificial intelligence technology currently offers the greatest potential for the development of scheduling tools with sufficient power and flexibility to handle realistic scheduling situations. Summarized here are the main features of the observatory scheduling problem, how artificial intelligence (AI) techniques can be applied, and recent progress in AI scheduling for Hubble Space Telescope.

A three-stage heuristic for harvest scheduling with access road network development

Treesearch

Mark M. Clark; Russell D. Meller; Timothy P. McDonald

2000-01-01

In this article we present a new model for the scheduling of forest harvesting with spatial and temporal constraints. Our approach is unique in that we incorporate access road network development into the harvest scheduling selection process. Due to the difficulty of solving the problem optimally, we develop a heuristic that consists of a solution construction stage...

KSC-2009-4590

NASA Image and Video Library

2009-08-11

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., the Solar Dynamics Observatory, or SDO, is moved, or gimbaled, during performance testing. All of the spacecraft science instruments are being tested in their last major evaluation before launch. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. In preparation for launch, engineers will perform a battery of comprehensive tests to ensure SDO can withstand the stresses and vibrations of the launch itself, as well as what it will encounter in the space environment after launch. Liftoff on an Atlas V rocket is scheduled for Dec. 4. Photo credit: NASA/Jack Pfaller

KSC-04PD-2671B

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. A worker at Astrotech Space Operations in Titusville, Fla., begins fueling the Deep Impact spacecraft. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-04PD-2669

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Workers at Astrotech Space Operations in Titusville, Fla., suit up before fueling the Deep Impact spacecraft. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-04PD-2668

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Workers at Astrotech Space Operations in Titusville, Fla., suit up before fueling the Deep Impact spacecraft. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-04PD-2671A

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. A worker at Astrotech Space Operations in Titusville, Fla., begins fueling the Deep Impact spacecraft. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

78 FR 17946 - Consolidated Tape Association; Notice of Filing and Immediate Effectiveness of the Sixteenth...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-25

... Network A and Network B data feeds. Consistent with current practice, within each of a firm's billable... fee schedules by compressing the current 14-tier Network A device rate schedule into four tiers, by... products, unprecedented levels of trading, internationalization and developments in portfolio analysis and...

A format for the interchange of scheduling models

NASA Technical Reports Server (NTRS)

Jaap, John P.; Davis, Elizabeth K.

1994-01-01

In recent years a variety of space-activity schedulers have been developed within the aerospace community. Space-activity schedulers are characterized by their need to handle large numbers of activities which are time-window constrained and make high demands on many scarce resources, but are minimally constrained by predecessor/successor requirements or critical paths. Two needs to exchange data between these schedulers have materialized. First, there is significant interest in comparing and evaluating the different scheduling engines to ensure that the best technology is applied to each scheduling endeavor. Second, there is a developing requirement to divide a single scheduling task among different sites, each using a different scheduler. In fact, the scheduling task for International Space Station Alpha (ISSA) will be distributed among NASA centers and among the international partners. The format used to interchange scheduling data for ISSA will likely use a growth version of the format discussed in this paper. The model interchange format (or MIF, pronounced as one syllable) discussed in this paper is a robust solution to the need to interchange scheduling requirements for space activities. It is highly extensible, human-readable, and can be generated or edited with common text editors. It also serves well the need to support a 'benchmark' data case which can be delivered on any computer platform.

Exploring a QoS Driven Scheduling Approach for Peer-to-Peer Live Streaming Systems with Network Coding

PubMed Central

Cui, Laizhong; Lu, Nan; Chen, Fu

2014-01-01

Most large-scale peer-to-peer (P2P) live streaming systems use mesh to organize peers and leverage pull scheduling to transmit packets for providing robustness in dynamic environment. The pull scheduling brings large packet delay. Network coding makes the push scheduling feasible in mesh P2P live streaming and improves the efficiency. However, it may also introduce some extra delays and coding computational overhead. To improve the packet delay, streaming quality, and coding overhead, in this paper are as follows. we propose a QoS driven push scheduling approach. The main contributions of this paper are: (i) We introduce a new network coding method to increase the content diversity and reduce the complexity of scheduling; (ii) we formulate the push scheduling as an optimization problem and transform it to a min-cost flow problem for solving it in polynomial time; (iii) we propose a push scheduling algorithm to reduce the coding overhead and do extensive experiments to validate the effectiveness of our approach. Compared with previous approaches, the simulation results demonstrate that packet delay, continuity index, and coding ratio of our system can be significantly improved, especially in dynamic environments. PMID:25114968

Enabling New Operations Concepts for Lunar and Mars Exploration

NASA Astrophysics Data System (ADS)

Jaap, John; Maxwell, Theresa

2005-02-01

The planning and scheduling of human space activities is an expensive and time-consuming task that seldom provides the crew with the control, flexibility, or insight that they need. During the past thirty years, scheduling software has seen only incremental improvements; however, software limitations continue to prevent even evolutionary improvements in the ``operations concept'' that is used for human space missions. Space missions are planned on the ground long before they are executed in space, and the crew has little input or influence on the schedule. In recent years the crew has been presented with a ``job jar'' of activities that they can do whenever they have time, but the contents of the jar is limited to tasks that do not use scarce shared resources and do not have external timing constraints. Consequently, the crew has no control over the schedule of the majority of their own tasks. As humans venture farther from earth for longer durations, it will become imperative that they have the ability to plan and schedule not only their own activities, but also the unattended activities of the systems, equipment, and robots on the journey with them. Significant software breakthroughs are required to enable the change in the operations concept. The crew does not have the time to build or modify the schedule by hand. They only need to issue a request to schedule a task and the system should automatically do the rest. Of course, the crew should not be required to build the complete schedule. Controllers on the ground should contribute the models and schedules where they have the better knowledge. The system must allow multiple simultaneous users, some on earth and some in space. The Mission Operations Laboratory at NASA's Marshall Space Flight Center has been researching and prototyping a modeling schema, scheduling engine, and system architecture that can enable the needed paradigm shift - it can make the crew autonomous. This schema and engine can be the core of a planning and scheduling system that would enable multiple planners, some on the earth and some in space, to build one integrated timeline. Its modeling schema can capture all the task requirements; its scheduling engine can build the schedule automatically; and its architecture can allow those (on earth and in space) with the best knowledge of the tasks to schedule them. This paper describes the enabling technology and proposes an operations concept for astronauts autonomously scheduling their activities and the activities around them.

Enabling New Operations Concepts for Lunar and Mars Exploration

NASA Technical Reports Server (NTRS)

Jaap, John; Maxwell, Theresa

2005-01-01

The planning and scheduling of human space activities is an expensive and time-consuming task that seldom provides the crew with the control, flexibility, or insight that they need. During the past thirty years, scheduling software has seen only incremental improvements; however, software limitations continue to prevent even evolutionary improvements in the operations concept that is used for human space missions. Space missions are planned on the ground long before they are executed in space, and the crew has little input or influence on the schedule. In recent years the crew has been presented with a job jar of activities that they can do whenever they have time, but the contents of the jar is limited to tasks that do not use scarce shared resources and do not have external timing constraints. Consequently, the crew has no control over the schedule of the majority of their own tasks. As humans venture farther from earth for longer durations, it will become imperative that they have the ability to plan and schedule not only their own activities, but also the unattended activities of the systems, equipment, and robots on the journey with them. Significant software breakthroughs are required to enable the change in the operations concept. The crew does not have the time to build or modify the schedule by hand. They only need to issue a request to schedule a task and the system should automatically do the rest. Of course, the crew should not be required to build the complete schedule. Controllers on the ground should contribute the models and schedules where they have the better knowledge. The system must allow multiple simultaneous users, some on earth and some in space. The Mission Operations Laboratory at NASA's Marshall Space flight Center has been researching and prototyping a modeling schema, scheduling engine, and system architecture that can enable the needed paradigm shift - it can make the crew autonomous. This schema and engine can be the core of a planning and scheduling system that would enable multiple planners, some on the earth and some in space, to build one integrated timeline. Its modeling schema can capture all the task requirements; its scheduling engine can build the schedule automatically, and its architecture can allow those (on earth and in space) with the best knowledge of the tasks to schedule them. This paper describes the enabling technology and proposes an operations concept for astronauts autonomously scheduling their activities and the activities around them.

Space communications scheduler: A rule-based approach to adaptive deadline scheduling

NASA Technical Reports Server (NTRS)

Straguzzi, Nicholas

1990-01-01

Job scheduling is a deceptively complex subfield of computer science. The highly combinatorial nature of the problem, which is NP-complete in nearly all cases, requires a scheduling program to intelligently transverse an immense search tree to create the best possible schedule in a minimal amount of time. In addition, the program must continually make adjustments to the initial schedule when faced with last-minute user requests, cancellations, unexpected device failures, quests, cancellations, unexpected device failures, etc. A good scheduler must be quick, flexible, and efficient, even at the expense of generating slightly less-than-optimal schedules. The Space Communication Scheduler (SCS) is an intelligent rule-based scheduling system. SCS is an adaptive deadline scheduler which allocates modular communications resources to meet an ordered set of user-specified job requests on board the NASA Space Station. SCS uses pattern matching techniques to detect potential conflicts through algorithmic and heuristic means. As a result, the system generates and maintains high density schedules without relying heavily on backtracking or blind search techniques. SCS is suitable for many common real-world applications.

An incentive-based distributed mechanism for scheduling divisible loads in tree networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carroll, T. E.; Grosu, D.

The underlying assumption of Divisible Load Scheduling (DLS) theory is that the pro-cessors composing the network are obedient, i.e., they do not “cheat” the scheduling algorithm. This assumption is unrealistic if the processors are owned by autonomous, self-interested organizations that have no a priori motivation for cooperation and they will manipulate the algorithm if it is beneficial to do so. In this paper, we address this issue by designing a distributed mechanism for scheduling divisible loads in tree net-works, called DLS-T, which provides incentives to processors for reporting their true processing capacity and executing their assigned load at full processingmore » capacity. We prove that the DLS-T mechanism computes the optimal allocation in an ex post Nash equilibrium. Finally, we simulate and study the mechanism under various network structures and processor parameters.« less

Final Report on DOE Project entitled Dynamic Optimized Advanced Scheduling of Bandwidth Demands for Large-Scale Science Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramamurthy, Byravamurthy

2014-05-05

In this project, developed scheduling frameworks for dynamic bandwidth demands for large-scale science applications. In particular, we developed scheduling algorithms for dynamic bandwidth demands in this project. Apart from theoretical approaches such as Integer Linear Programming, Tabu Search and Genetic Algorithm heuristics, we have utilized practical data from ESnet OSCARS project (from our DOE lab partners) to conduct realistic simulations of our approaches. We have disseminated our work through conference paper presentations and journal papers and a book chapter. In this project we addressed the problem of scheduling of lightpaths over optical wavelength division multiplexed (WDM) networks. We published severalmore » conference papers and journal papers on this topic. We also addressed the problems of joint allocation of computing, storage and networking resources in Grid/Cloud networks and proposed energy-efficient mechanisms for operatin optical WDM networks.« less

STS-90 Columbia RSS rollback

NASA Technical Reports Server (NTRS)

1998-01-01

With the Rotating Service Structure (RSS) rolled back, at left, the Space Shuttle Columbia is nearly ready for launch of STS-90. Rollback of the RSS is a major preflight milestone, typically occurring during the T-11-hour hold on L-1 (the day before launch). The scheduled launch of Columbia on Apr. 16 from Launch Pad 39B was postponed 24 hours due to difficulty with network signal processor No. 2 on the orbiter. This device formats data and voice communications between the ground and the Space Shuttle. The unit, which is located in the orbiter's mid-deck, will be removed and replaced. Prior to launch, one of the final steps will be to load the external tank with approximately 500,000 gallons of liquid hydrogen and liquid oxygen for fueling the orbiters three main engines. Tanking had not yet begun when the launch scheduled for Apr. 16 was scrubbed. STS-90 is slated to be the launch of Neurolab, a nearly 17-day mission to examine the effects of spaceflight on the brain, spinal cord, peripheral nerves and sensory organs in the human body.

KSC-39b

NASA Image and Video Library

1998-04-15

With the Rotating Service Structure (RSS) rolled back, at left, the Space Shuttle Columbia is nearly ready for launch of STS-90. Rollback of the RSS is a major preflight milestone, typically occurring during the T-11-hour hold on L-1 (the day before launch). The scheduled launch of Columbia on Apr. 16 from Launch Pad 39B was postponed 24 hours due to difficulty with network signal processor No. 2 on the orbiter. This device formats data and voice communications between the ground and the Space Shuttle. The unit, which is located in the orbiter's mid-deck, will be removed and replaced. Prior to launch, one of the final steps will be to load the external tank with approximately 500,000 gallons of liquid hydrogen and liquid oxygen for fueling the orbiters three main engines. Tanking had not yet begun when the launch scheduled for Apr. 16 was scrubbed. STS-90 is slated to be the launch of Neurolab, a nearly 17-day mission to examine the effects of spaceflight on the brain, spinal cord, peripheral nerves and sensory organs in the human body

Scheduling and Topology Design in Networks with Directional Antennas

DTIC Science & Technology

2017-05-19

emergency response networks was recently studied in [14] and [15]. This work examines the topology control problem in group - based wireless networks that...Broadcast Fig. 7: Max-min throughput ⇢ versus number of nodes for non -uniform edge capacities [14] T. Suzuki, et al. “Directional Antenna Control based...Scheduling and Topology Design in Networks with Directional Antennas Thomas Stahlbuhk, Nathaniel M. Jones, Brooke Shrader Lincoln Laboratory

Power Grid Maintenance Scheduling Intelligence Arrangement Supporting System Based on Power Flow Forecasting

NASA Astrophysics Data System (ADS)

Xie, Chang; Wen, Jing; Liu, Wenying; Wang, Jiaming

With the development of intelligent dispatching, the intelligence level of network control center full-service urgent need to raise. As an important daily work of network control center, the application of maintenance scheduling intelligent arrangement to achieve high-quality and safety operation of power grid is very important. By analyzing the shortages of the traditional maintenance scheduling software, this paper designs a power grid maintenance scheduling intelligence arrangement supporting system based on power flow forecasting, which uses the advanced technologies in maintenance scheduling, such as artificial intelligence, online security checking, intelligent visualization techniques. It implements the online security checking of maintenance scheduling based on power flow forecasting and power flow adjusting based on visualization, in order to make the maintenance scheduling arrangement moreintelligent and visual.

A space station onboard scheduling assistant

NASA Technical Reports Server (NTRS)

Brindle, A. F.; Anderson, B. H.

1988-01-01

One of the goals for the Space Station is to achieve greater autonomy, and have less reliance on ground commanding than previous space missions. This means that the crew will have to take an active role in scheduling and rescheduling their activities onboard, perhaps working from preliminary schedules generated on the ground. Scheduling is a time intensive task, whether performed manually or automatically, so the best approach to solving onboard scheduling problems may involve crew members working with an interactive software scheduling package. A project is described which investigates a system that uses knowledge based techniques for the rescheduling of experiments within the Materials Technology Laboratory of the Space Station. Particular attention is paid to: (1) methods for rapid response rescheduling to accommodate unplanned changes in resource availability, (2) the nature of the interface to the crew, (3) the representation of the many types of data within the knowledge base, and (4) the possibility of applying rule-based and constraint-based reasoning methods to onboard activity scheduling.

Dynamic Sensor Networks

DTIC Science & Technology

2004-03-01

turned off. SLEEP Set the timer for 30 seconds before scheduled transmit time, then sleep the processor. WAKE When timer trips, power up the processor...slots where none of its neighbors are schedule to transmit. This allows the sensor nodes to perform a simple power man- agement scheme that puts the...routing This simple case study highlights the following crucial observation: optimal traffic scheduling in energy constrained networks requires future

Infusion of innovative technologies for mission operations

NASA Astrophysics Data System (ADS)

Donati, Alessandro

2010-11-01

The Advanced Mission Concepts and Technologies Office (Mission Technologies Office, MTO for short) at the European Space Operations Centre (ESOC) of ESA is entrusted with research and development of innovative mission operations concepts systems and provides operations support to special projects. Visions of future missions and requests for improvements from currently flying missions are the two major sources of inspiration to conceptualize innovative or improved mission operations processes. They include monitoring and diagnostics, planning and scheduling, resource management and optimization. The newly identified operations concepts are then proved by means of prototypes, built with embedded, enabling technology and deployed as shadow applications in mission operations for an extended validation phase. The technology so far exploited includes informatics, artificial intelligence and operational research branches. Recent outstanding results include artificial intelligence planning and scheduling applications for Mars Express, advanced integrated space weather monitoring system for the Integral space telescope and a suite of growing client applications for MUST (Mission Utilities Support Tools). The research, development and validation activities at the Mission technologies office are performed together with a network of research institutes across Europe. The objective is narrowing the gap between enabling and innovative technology and space mission operations. The paper first addresses samples of technology infusion cases with their lessons learnt. The second part is focused on the process and the methodology used at the Mission technologies office to fulfill its objectives.

TDRS-M NASA Social

NASA Image and Video Library

2017-08-17

Social media gather in Kennedy Space Center’s Press Site auditorium for a briefing focused on preparations to launch NASA's Tracking and Data Relay Satellite, TDRS-M. The latest spacecraft destined for the agency's constellation of communications satellites, TDRS-M will allow nearly continuous contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. Liftoff atop a United Launch Alliance Atlas V rocket is scheduled to take place from Space Launch Complex 41 at Cape Canaveral Air Force Station at 8:03 a.m. EDT Aug. 18. NASA Social Media Team includes: Emily Furfaro and Amber Jacobson. Guest speakers include: Badri Younes, Deputy Associate Administrator for Space Communications and Navigation at NASA Headquarters in Washington; Dave Littmann, Project Manager for TDRS-M at NASA’s Goddard Space Flight Center; Neil Mallik, NASA Deputy Network Director for Human Spaceflight; Nicole Mann, NASA Astronaut; Steve Bowen, NASA Astronaut; Skip Owen, NASA Launch Services; Scott Messer, United Launch Alliance Program Manager for NASA Missions.

The JOVE initiative - A NASA/university Joint Venture in space science

NASA Technical Reports Server (NTRS)

Six, F.; Chappell, R.

1990-01-01

The JOVE (NASA/university Joint Venture in space science) initiative is a point program between NASA and institutions of higher education whose aim is to bring about an extensive merger between these two communities. The project is discussed with emphasis on suggested contributions of partnership members, JOVE process timeline, and project schedules and costs. It is suggested that NASA provide a summer resident research associateship (one ten week stipend); scientific on-line data from space missions; an electronic network and work station, providing a link to the data base and to other scientists; matching student support, both undergraduate and graduate; matching summer salary for up to three faculty participants; and travel funds. The universities will be asked to provide research time for faculty participants, matching student support, matching summer salary for faculty participants, an instructional unit in space science, and an outreach program to pre-college students.

TDRS-L spacecraft lift to mate on Atlas V

NASA Image and Video Library

2014-01-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Vertical Integration Facility at Launch Complex 41, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft is lifted for mounting atop a United Launch Alliance Atlas V rocket. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on Jan. 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Dimitri Gerondidakis

TDRS-L spacecraft lift to mate on Atlas V

NASA Image and Video Library

2014-01-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Vertical Integration Facility at Launch Complex 41, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft is moved into position for mating atop a United Launch Alliance Atlas V rocket. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on Jan. 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Dimitri Gerondidakis

TDRS-L Spacecraft Fairing Encapsulation

NASA Image and Video Library

2014-01-08

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, United Launch Alliance engineers and technicians encapsulate the Tracking and Data Relay Satellite, or TDRS-L, spacecraft in its payload fairing. TDRS-L will then be transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

TDRS-L Spacecraft Fairing Encapsulation

NASA Image and Video Library

2014-01-08

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft is being encapsulated in its payload fairing prior to being transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

TDRS-L Spacecraft Fairing Encapsulation

NASA Image and Video Library

2014-01-08

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, the Tracking and Data Relay Satellite, or TDRS-L, spacecraft is being encapsulated in its payload fairing in preparation for begin transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

TDRS-L Spacecraft Fairing Encapsulation

NASA Image and Video Library

2014-01-08

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft has been encapsulated in its payload fairing. TDRS-L will then be transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

KSC-2013-3786

NASA Image and Video Library

2013-11-01

CAPE CANAVERAL, Fla. – The United Launch Alliance Atlas V launch vehicle, left, and Centaur upper stage that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to the hangar at the Atlas Spaceflight Operations Center on Cape Canaveral Air Force Station for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Jim Grossman

TDRS-L Spacecraft is Lifted Onto Transporter

NASA Image and Video Library

2014-01-10

TITUSVILLE, Fla. – Encapsulated in its payload fairing, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft is being mounted on a transporter for its trip from the Astrotech payload processing facility in Titusville to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Kim Shiflett

KSC-2013-4402

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, engineers and technicians support lifting the first stage of the United Launch Alliance Atlas V rocket during stacking operations in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

TDRS-L Spacecraft Transported from Astrotech to SLC

NASA Image and Video Library

2014-01-13

TITUSVILLE, Fla. – Encapsulated in its payload fairing, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft begins it trip from the Astrotech payload processing facility in Titusville to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Dimitri Gerondidakis

KSC-2013-4413

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, a technician support lifting the first stage of the United Launch Alliance Atlas V rocket during stacking operations in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

TDRS-L Spacecraft Fairing Encapsulation

NASA Image and Video Library

2014-01-08

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, United Launch Alliance engineers and technicians ensure precision as the Tracking and Data Relay Satellite, or TDRS-L, spacecraft is being encapsulated in its payload fairing in preparation for begin transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

TDRS-L Spacecraft Transported from Astrotech to SLC

NASA Image and Video Library

2014-01-13

CAPE CANAVERAL, Fla. – Encapsulated in its payload fairing, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft arrives at Cape Canaveral Air Force Station's Vertical Integration Facility at Launch Complex 41. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Dimitri Gerondidakis

KSC-2013-4420

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – The United Launch Alliance Centaur second stage that will help boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit arrives at Cape Canaveral Air Force Station's Launch Complex 41. It will be lifted and mounted atop the Atlas V first stage already in position inside the Vertical Integration Facility. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

KSC-2013-4412

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, engineers and technicians support lifting the first stage of the United Launch Alliance Atlas V rocket during stacking operations in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

TDRS-L spacecraft lift to mate on Atlas V

NASA Image and Video Library

2014-01-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station's Vertical Integration Facility at Launch Complex 41, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft has been mated atop a United Launch Alliance Atlas V rocket. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on Jan. 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Dimitri Gerondidakis

KSC-2013-3782

NASA Image and Video Library

2013-11-01

PORT CANAVERAL, Fla. – Following arrival at Port Canaveral, Fla., the United Launch Alliance Atlas V first stage and Centaur upper stage that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to Cape Canaveral Air Force Station's Atlas Spaceflight Operations Center for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Kim Shiflett

TDRS-L Spacecraft is Lifted Onto Transporter

NASA Image and Video Library

2014-01-10

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft has been encapsulated in its payload fairing in preparation for begin transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Kim Shiflett

TDRS-L Spacecraft Fairing Encapsulation

NASA Image and Video Library

2014-01-08

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, the Tracking and Data Relay Satellite, or TDRS-L, spacecraft is being encapsulated in its payload fairing in preparation for being transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

KSC-2013-4404

NASA Image and Video Library

2013-12-13

CAPE CANAVERAL, Fla. – At Cape Canaveral Air Force Station, engineers and technicians support lifting the first stage of the United Launch Alliance Atlas V rocket during stacking operations in the Vertical Integration Facility at Launch Complex 41. The vehicle will be used to boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft to orbit. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/Charisse Nahser

TDRS-L Spacecraft Fairing Encapsulation

NASA Image and Video Library

2014-01-08

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft is being encapsulated in its payload fairing in preparation for begin transported to Launch Complex 41 at Cape Canaveral Air Force Station. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on January 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

KSC-2013-3781

NASA Image and Video Library

2013-11-01

PORT CANAVERAL, Fla. – Following arrival at Port Canaveral, Fla., the United Launch Alliance Atlas V first stage and Centaur upper stage that will boost the Tracking and Data Relay Satellite, or TDRS-L, spacecraft into orbit is being transported to Cape Canaveral Air Force Station's Atlas Spaceflight Operations Center for checkout in preparation for launch. TDRS-L is the second of three next-generation satellites designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay service to missions such as the Hubble Space Telescope and International Space Station. For more information, visit: http://www.nasa.gov/content/tracking-and-data-relay-satellite-tdrs/ Photo credit: NASA/ Kim Shiflett

TDRS-L spacecraft lift to mate on Atlas V

NASA Image and Video Library

2014-01-13

CAPE CANAVERAL, Fla. – Encapsulated in its payload fairing, NASA's Tracking and Data Relay Satellite, or TDRS-L, spacecraft arrives at Cape Canaveral Air Force Station's Vertical Integration Facility at Launch Complex 41. The TDRS-L satellite will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop a United Launch Alliance Atlas V rocket on Jan. 23, 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html Photo credit: NASA/Dimitri Gerondidakis

TDRS-L Media Day

NASA Image and Video Library

2014-01-03

TITUSVILLE, Fla. – Inside the Astrotech payload processing facility in Titusville, members of the news media are given an opportunity for an up-close look at the payload fairing that will encapsulate the Tracking and Data Relay Satellite, or TDRS-L, spacecraft. Journalists visited Astrotech as part of TDRS-L Media Day to conduct interviews and photograph the satellite that will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

KSC-2010-5379

NASA Image and Video Library

2010-11-01

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, NASA Associate Administrator for Space Operations Bill Gerstenmaier addresses participants of the STS-133 Tweetup. NASA is hosting about 150 of its Twitter followers from around the world and several dozen states and providing them with a behind-the-scenes perspective to share with their own followers on the social networking service. The "Tweeps," as NASA calls them, will have a chance to tour Kennedy and meet with shuttle technicians, managers, engineers and astronauts. They also will receive a demonstration of Robonaut, a human-like robot similar to the one that will be delivered to the International Space Station on the STS-133 mission. Space shuttle Discovery and its STS-133 crew are scheduled to launch Nov. 3 at 3:52 p.m. EDT. For more information on the upcoming mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

KSC-2010-5380

NASA Image and Video Library

2010-11-01

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, space shuttle Discovery Flow Director Stephanie Stilson addresses participants of the STS-133 Tweetup. NASA is hosting about 150 of its Twitter followers from around the world and several dozen states and providing them with a behind-the-scenes perspective to share with their own followers on the social networking service. The "Tweeps," as NASA calls them, will have a chance to tour Kennedy and meet with shuttle technicians, managers, engineers and astronauts. They also will receive a demonstration of Robonaut, a human-like robot similar to the one that will be delivered to the International Space Station on the STS-133 mission. Space shuttle Discovery and its STS-133 crew are scheduled to launch Nov. 3 at 3:52 p.m. EDT. For more information on the upcoming mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

KSC-2010-5378

NASA Image and Video Library

2010-11-01

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, NASA Associate Administrator for Space Operations Bill Gerstenmaier addresses participants of the STS-133 Tweetup. NASA is hosting about 150 of its Twitter followers from around the world and several dozen states and providing them with a behind-the-scenes perspective to share with their own followers on the social networking service. The "Tweeps," as NASA calls them, will have a chance to tour Kennedy and meet with shuttle technicians, managers, engineers and astronauts. They also will receive a demonstration of Robonaut, a human-like robot similar to the one that will be delivered to the International Space Station on the STS-133 mission. Space shuttle Discovery and its STS-133 crew are scheduled to launch Nov. 3 at 3:52 p.m. EDT. For more information on the upcoming mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

Spike: AI scheduling for Hubble Space Telescope after 18 months of orbital operations

NASA Technical Reports Server (NTRS)

Johnston, Mark D.

1992-01-01

This paper is a progress report on the Spike scheduling system, developed by the Space Telescope Science Institute for long-term scheduling of Hubble Space Telescope (HST) observations. Spike is an activity-based scheduler which exploits artificial intelligence (AI) techniques for constraint representation and for scheduling search. The system has been in operational use since shortly after HST launch in April 1990. Spike was adopted for several other satellite scheduling problems; of particular interest was the demonstration that the Spike framework is sufficiently flexible to handle both long-term and short-term scheduling, on timescales of years down to minutes or less. We describe the recent progress made in scheduling search techniques, the lessons learned from early HST operations, and the application of Spike to other problem domains. We also describe plans for the future evolution of the system.

A Target Coverage Scheduling Scheme Based on Genetic Algorithms in Directional Sensor Networks

PubMed Central

Gil, Joon-Min; Han, Youn-Hee

2011-01-01

As a promising tool for monitoring the physical world, directional sensor networks (DSNs) consisting of a large number of directional sensors are attracting increasing attention. As directional sensors in DSNs have limited battery power and restricted angles of sensing range, maximizing the network lifetime while monitoring all the targets in a given area remains a challenge. A major technique to conserve the energy of directional sensors is to use a node wake-up scheduling protocol by which some sensors remain active to provide sensing services, while the others are inactive to conserve their energy. In this paper, we first address a Maximum Set Covers for DSNs (MSCD) problem, which is known to be NP-complete, and present a greedy algorithm-based target coverage scheduling scheme that can solve this problem by heuristics. This scheme is used as a baseline for comparison. We then propose a target coverage scheduling scheme based on a genetic algorithm that can find the optimal cover sets to extend the network lifetime while monitoring all targets by the evolutionary global search technique. To verify and evaluate these schemes, we conducted simulations and showed that the schemes can contribute to extending the network lifetime. Simulation results indicated that the genetic algorithm-based scheduling scheme had better performance than the greedy algorithm-based scheme in terms of maximizing network lifetime. PMID:22319387

An Enabling Technology for New Planning and Scheduling Paradigms

NASA Technical Reports Server (NTRS)

Jaap, John; Davis, Elizabeth

2004-01-01

The Night Projects Directorate at NASA's Marshall Space Flight Center is developing a new planning and scheduling environment and a new scheduling algorithm to enable a paradigm shift in planning and scheduling concepts. Over the past 33 years Marshall has developed and evolved a paradigm for generating payload timelines for Skylab, Spacelab, various other Shuttle payloads, and the International Space Station. The current paradigm starts by collecting the requirements, called ?ask models," from the scientists and technologists for the tasks that are to be scheduled. Because of shortcomings in the current modeling schema, some requirements are entered as notes. Next, a cadre with knowledge of vehicle and hardware modifies these models to encompass and be compatible with the hardware model; again, notes are added when the modeling schema does not provide a better way to represent the requirements. Finally, the models are modified to be compatible with the scheduling engine. Then the models are submitted to the scheduling engine for automatic scheduling or, when requirements are expressed in notes, the timeline is built manually. A future paradigm would provide a scheduling engine that accepts separate science models and hardware models. The modeling schema would have the capability to represent all the requirements without resorting to notes. Furthermore, the scheduling engine would not require that the models be modified to account for the capabilities (limitations) of the scheduling engine. The enabling technology under development at Marshall has three major components: (1) A new modeling schema allows expressing all the requirements of the tasks without resorting to notes or awkward contrivances. The chosen modeling schema is both maximally expressive and easy to use. It utilizes graphical methods to show hierarchies of task constraints and networks of temporal relationships. (2) A new scheduling algorithm automatically schedules the models without the intervention of a scheduling expert. The algorithm is tuned for the constraint hierarchies and the complex temporal relationships provided by the modeling schema. It has an extensive search algorithm that can exploit timing flexibilities and constraint and relationship options. (3) An innovative architecture allows multiple remote users to simultaneously model science and technology requirements and other users to model vehicle and hardware characteristics. The architecture allows the remote users to submit scheduling requests directly to the scheduling engine and immediately see the results. These three components are integrated so that science and technology experts with no knowledge of the vehicle or hardware subsystems and no knowledge of the internal workings of the scheduling engine have the ability to build and submit scheduling requests and see the results. The immediate feedback will hone the users' modeling skills and ultimately enable them to produce the desired timeline. This paper summarizes the three components of the enabling technology and describes how this technology would make a new paradigm possible.

Space station needs, attributes, and architectural options study. Volume 3: Cost and benefits

NASA Technical Reports Server (NTRS)

1983-01-01

Cost and schedule, cost/incremental capability, and schedule impact analyses are presented. Quantifiable benefits, space technology, non-quantifiable benefits, and space commercialization are addressed.

Experimental demonstration of bandwidth on demand (BoD) provisioning based on time scheduling in software-defined multi-domain optical networks

NASA Astrophysics Data System (ADS)

Zhao, Yongli; Li, Yajie; Wang, Xinbo; Chen, Bowen; Zhang, Jie

2016-09-01

A hierarchical software-defined networking (SDN) control architecture is designed for multi-domain optical networks with the Open Daylight (ODL) controller. The OpenFlow-based Control Virtual Network Interface (CVNI) protocol is deployed between the network orchestrator and the domain controllers. Then, a dynamic bandwidth on demand (BoD) provisioning solution is proposed based on time scheduling in software-defined multi-domain optical networks (SD-MDON). Shared Risk Link Groups (SRLG)-disjoint routing schemes are adopted to separate each tenant for reliability. The SD-MDON testbed is built based on the proposed hierarchical control architecture. Then the proposed time scheduling-based BoD (Ts-BoD) solution is experimentally demonstrated on the testbed. The performance of the Ts-BoD solution is evaluated with respect to blocking probability, resource utilization, and lightpath setup latency.

The Ames-Lockheed orbiter processing scheduling system

NASA Technical Reports Server (NTRS)

Zweben, Monte; Gargan, Robert

1991-01-01

A general purpose scheduling system and its application to Space Shuttle Orbiter Processing at the Kennedy Space Center (KSC) are described. Orbiter processing entails all the inspection, testing, repair, and maintenance necessary to prepare the Shuttle for launch and takes place within the Orbiter Processing Facility (OPF) at KSC, the Vehicle Assembly Building (VAB), and on the launch pad. The problems are extremely combinatoric in that there are thousands of tasks, resources, and other temporal considerations that must be coordinated. Researchers are building a scheduling tool that they hope will be an integral part of automating the planning and scheduling process at KSC. The scheduling engine is domain independent and is also being applied to Space Shuttle cargo processing problems as well as wind tunnel scheduling problems.

Remote Operations of the Deep Space Network Radio Science Subsystem

NASA Astrophysics Data System (ADS)

Caetta, J.; Asmar, S.; Abbate, S.; Connally, M.; Goltz, G.

1998-04-01

The capability for scientists to remotely control systems located at the Deep Space Network facilities only recently has been incorporated in the design and implementation of new equipment. However, time lines for the implementation, distribution, and operational readiness of such systems can extend much farther into the future than the users can wait. The Radio Science Systems Group was faced with just that circumstance; new hardware was not scheduled to become operational for several years, but the increasing number of experiments and configurations for Cassini, Galileo, Mars missions, and other flight projects made that time frame impractical because of the associated increasing risk of not acquiring critical data. Therefore, a method of interfacing with the current radio science subsystem has been developed and used with a high degree of success, although with occasional problems due to this capability not having been originally designed into the system. This article discusses both the method and the problems involved in integrating this new (remote) method of control with a legacy system.

Space shuttle maintenance program planning document

NASA Technical Reports Server (NTRS)

Brown, D. V.

1972-01-01

A means for developing a space shuttle maintenance program which will be acceptable to the development centers, the operators (KSC and AF), and the manufacturer is presented. The general organization and decision processes for determining the essential scheduled maintenance requirements for the space shuttle orbiter are outlined. The development of initial scheduled maintenance programs is discussed. The remaining maintenance, that is non-scheduled or non-routine maintenance, is directed by the findings of the scheduled maintenance program and the normal operation of the shuttle. The remaining maintenance consists of maintenance actions to correct discrepancies noted during scheduled maintenance tasks, nonscheduled maintenance, normal operation, or condition monitoring.

Time-optimum packet scheduling for many-to-one routing in wireless sensor networks

USGS Publications Warehouse

Song, W.-Z.; Yuan, F.; LaHusen, R.; Shirazi, B.

2007-01-01

This paper studies the wireless sensor networks (WSN) application scenario with periodical traffic from all sensors to a sink. We present a time-optimum and energy-efficient packet scheduling algorithm and its distributed implementation. We first give a general many-to-one packet scheduling algorithm for wireless networks, and then prove that it is time-optimum and costs [image omitted], N(u0)-1) time slots, assuming each node reports one unit of data in each round. Here [image omitted] is the total number of sensors, while [image omitted] denotes the number of sensors in a sink's largest branch subtree. With a few adjustments, we then show that our algorithm also achieves time-optimum scheduling in heterogeneous scenarios, where each sensor reports a heterogeneous amount of data in each round. Then we give a distributed implementation to let each node calculate its duty-cycle locally and maximize efficiency globally. In this packet-scheduling algorithm, each node goes to sleep whenever it is not transceiving, so that the energy waste of idle listening is also mitigated. Finally, simulations are conducted to evaluate network performance using the Qualnet simulator. Among other contributions, our study also identifies the maximum reporting frequency that a deployed sensor network can handle.

Energy efficient mechanisms for high-performance Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Alsaify, Baha'adnan

2009-12-01

Due to recent advances in microelectronics, the development of low cost, small, and energy efficient devices became possible. Those advances led to the birth of the Wireless Sensor Networks (WSNs). WSNs consist of a large set of sensor nodes equipped with communication capabilities, scattered in the area to monitor. Researchers focus on several aspects of WSNs. Such aspects include the quality of service the WSNs provide (data delivery delay, accuracy of data, etc...), the scalability of the network to contain thousands of sensor nodes (the terms node and sensor node are being used interchangeably), the robustness of the network (allowing the network to work even if a certain percentage of nodes fails), and making the energy consumption in the network as low as possible to prolong the network's lifetime. In this thesis, we present an approach that can be applied to the sensing devices that are scattered in an area for Sensor Networks. This work will use the well-known approach of using a awaking scheduling to extend the network's lifespan. We designed a scheduling algorithm that will reduce the delay's upper bound the reported data will experience, while at the same time keeps the advantages that are offered by the use of the awaking scheduling -- the energy consumption reduction which will lead to the increase in the network's lifetime. The wakeup scheduling is based on the location of the node relative to its neighbors and its distance from the Base Station (the terms Base Station and sink are being used interchangeably). We apply the proposed method to a set of simulated nodes using the "ONE Simulator". We test the performance of this approach with three other approaches -- Direct Routing technique, the well known LEACH algorithm, and a multi-parent scheduling algorithm. We demonstrate a good improvement on the network's quality of service and a reduction of the consumed energy.

24 CFR 982.624 - Manufactured home space rental: Utility allowance schedule.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Manufactured home space rental... Special Housing Types Manufactured Home Space Rental § 982.624 Manufactured home space rental: Utility allowance schedule. The PHA must establish utility allowances for manufactured home space rental. For the...

24 CFR 982.624 - Manufactured home space rental: Utility allowance schedule.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Manufactured home space rental... Special Housing Types Manufactured Home Space Rental § 982.624 Manufactured home space rental: Utility allowance schedule. The PHA must establish utility allowances for manufactured home space rental. For the...

24 CFR 982.624 - Manufactured home space rental: Utility allowance schedule.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 4 2014-04-01 2014-04-01 false Manufactured home space rental... Special Housing Types Manufactured Home Space Rental § 982.624 Manufactured home space rental: Utility allowance schedule. The PHA must establish utility allowances for manufactured home space rental. For the...

Peer-to-peer Cooperative Scheduling Architecture for National Grid Infrastructure

NASA Astrophysics Data System (ADS)

Matyska, Ludek; Ruda, Miroslav; Toth, Simon

For some ten years, the Czech National Grid Infrastructure MetaCentrum uses a single central PBSPro installation to schedule jobs across the country. This centralized approach keeps a full track about all the clusters, providing support for jobs spanning several sites, implementation for the fair-share policy and better overall control of the grid environment. Despite a steady progress in the increased stability and resilience to intermittent very short network failures, growing number of sites and processors makes this architecture, with a single point of failure and scalability limits, obsolete. As a result, a new scheduling architecture is proposed, which relies on higher autonomy of clusters. It is based on a peer to peer network of semi-independent schedulers for each site or even cluster. Each scheduler accepts jobs for the whole infrastructure, cooperating with other schedulers on implementation of global policies like central job accounting, fair-share, or submission of jobs across several sites. The scheduling system is integrated with the Magrathea system to support scheduling of virtual clusters, including the setup of their internal network, again eventually spanning several sites. On the other hand, each scheduler is local to one of several clusters and is able to directly control and submit jobs to them even if the connection of other scheduling peers is lost. In parallel to the change of the overall architecture, the scheduling system itself is being replaced. Instead of PBSPro, chosen originally for its declared support of large scale distributed environment, the new scheduling architecture is based on the open-source Torque system. The implementation and support for the most desired properties in PBSPro and Torque are discussed and the necessary modifications to Torque to support the MetaCentrum scheduling architecture are presented, too.

KSC-2009-4587

NASA Image and Video Library

2009-08-11

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., the Solar Dynamics Observatory, or SDO, is undergoing performance testing. The high-gain antenna seen at center left will be moved, or gimbaled. All of the spacecraft science instruments are being tested in their last major evaluation before launch. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. In preparation for launch, engineers will perform a battery of comprehensive tests to ensure SDO can withstand the stresses and vibrations of the launch itself, as well as what it will encounter in the space environment after launch. Liftoff on an Atlas V rocket is scheduled for Dec. 4. Photo credit: NASA/Jack Pfaller

Static-dynamic hybrid communication scheduling and control co-design for networked control systems.

PubMed

Wen, Shixi; Guo, Ge

2017-11-01

In this paper, the static-dynamic hybrid communication scheduling and control co-design is proposed for the networked control systems (NCSs) to solve the capacity limitation of the wireless communication network. The analytical most regular binary sequences (MRBSs) are used as the communication scheduling function for NCSs. When the communication conflicts yielded in the binary sequence MRBSs, a dynamic scheduling strategy is proposed to on-line reallocate the medium access status for each plant. Under such static-dynamic hybrid scheduling policy, plants in NCSs are described as the non-uniform sampled-control systems, whose controller have a group of controller gains and switch according to the sampling interval yielded by the binary sequence. A useful communication scheduling and control co-design framework is proposed for the NCSs to simultaneously decide the controller gains and the parameters used to generate the communication sequences MRBS. Numerical example and realistic example are respectively given to demonstrate the effectiveness of the proposed co-design method. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Objectively Optimized Observation Direction System Providing Situational Awareness for a Sensor Web

NASA Astrophysics Data System (ADS)

Aulov, O.; Lary, D. J.

2010-12-01

There is great utility in having a flexible and automated objective observation direction system for the decadal survey missions and beyond. Such a system allows us to optimize the observations made by suite of sensors to address specific goals from long term monitoring to rapid response. We have developed such a prototype using a network of communicating software elements to control a heterogeneous network of sensor systems, which can have multiple modes and flexible viewing geometries. Our system makes sensor systems intelligent and situationally aware. Together they form a sensor web of multiple sensors working together and capable of automated target selection, i.e. the sensors “know” where they are, what they are able to observe, what targets and with what priorities they should observe. This system is implemented in three components. The first component is a Sensor Web simulator. The Sensor Web simulator describes the capabilities and locations of each sensor as a function of time, whether they are orbital, sub-orbital, or ground based. The simulator has been implemented using AGIs Satellite Tool Kit (STK). STK makes it easy to analyze and visualize optimal solutions for complex space scenarios, and perform complex analysis of land, sea, air, space assets, and shares results in one integrated solution. The second component is target scheduler that was implemented with STK Scheduler. STK Scheduler is powered by a scheduling engine that finds better solutions in a shorter amount of time than traditional heuristic algorithms. The global search algorithm within this engine is based on neural network technology that is capable of finding solutions to larger and more complex problems and maximizing the value of limited resources. The third component is a modeling and data assimilation system. It provides situational awareness by supplying the time evolution of uncertainty and information content metrics that are used to tell us what we need to observe and the priority we should give to the observations. A prototype of this component was implemented with AutoChem. AutoChem is NASA release software constituting an automatic code generation, symbolic differentiator, analysis, documentation, and web site creation tool for atmospheric chemical modeling and data assimilation. Its model is explicit and uses an adaptive time-step, error monitoring time integration scheme for stiff systems of equations. AutoChem was the first model to ever have the facility to perform 4D-Var data assimilation and Kalman filter. The project developed a control system with three main accomplishments. First, fully multivariate observational and theoretical information with associated uncertainties was combined using a full Kalman filter data assimilation system. Second, an optimal distribution of the computations and of data queries was achieved by utilizing high performance computers/load balancing and a set of automatically mirrored databases. Third, inter-instrument bias correction was performed using machine learning. The PI for this project was Dr. David Lary of the UMBC Joint Center for Earth Systems Technology at NASA/Goddard Space Flight Center.

Deep Space Network (DSN), Network Operations Control Center (NOCC) computer-human interfaces

NASA Technical Reports Server (NTRS)

Ellman, Alvin; Carlton, Magdi

1993-01-01

The Network Operations Control Center (NOCC) of the DSN is responsible for scheduling the resources of DSN, and monitoring all multi-mission spacecraft tracking activities in real-time. Operations performs this job with computer systems at JPL connected to over 100 computers at Goldstone, Australia and Spain. The old computer system became obsolete, and the first version of the new system was installed in 1991. Significant improvements for the computer-human interfaces became the dominant theme for the replacement project. Major issues required innovating problem solving. Among these issues were: How to present several thousand data elements on displays without overloading the operator? What is the best graphical representation of DSN end-to-end data flow? How to operate the system without memorizing mnemonics of hundreds of operator directives? Which computing environment will meet the competing performance requirements? This paper presents the technical challenges, engineering solutions, and results of the NOCC computer-human interface design.

Network Control Center User Planning System (NCC UPS)

NASA Astrophysics Data System (ADS)

Dealy, Brian

1991-09-01

NCC UPS is presented in the form of the viewgraphs. The following subject areas are covered: UPS overview; NCC UPS role; major NCC UPS functional requirements; interactive user access levels; UPS interfaces; interactive user subsystem; interface navigation; scheduling screen hierarchy; interactive scheduling input panels; autogenerated schedule request panel; schedule data tabular display panel; schedule data graphic display panel; graphic scheduling aid design; and schedule data graphic display.

Network Control Center User Planning System (NCC UPS)

NASA Technical Reports Server (NTRS)

Dealy, Brian

1991-01-01

NCC UPS is presented in the form of the viewgraphs. The following subject areas are covered: UPS overview; NCC UPS role; major NCC UPS functional requirements; interactive user access levels; UPS interfaces; interactive user subsystem; interface navigation; scheduling screen hierarchy; interactive scheduling input panels; autogenerated schedule request panel; schedule data tabular display panel; schedule data graphic display panel; graphic scheduling aid design; and schedule data graphic display.

The Solaris-Panoptes Global Network of Robotic Telescopes and the Borowiec Satellite Laser Ranging System for SST: A Progress Report

NASA Astrophysics Data System (ADS)

Konacki, M.; Lejba, P.; Sybilski, P.; Pawłaszek, R.; Kozłowski, S.; Suchodolski, T.; Słonina, M.; Litwicki, M.; Sybilska, A.; Rogowska, B.; Kolb, U.; Burwitz, V.; Baader, J.; Groot, P.; Bloemen, S.; Ratajczak, M.; Hełminiak, K.; Borek, R.; Chodosiewicz, P.; Chimicz, A.

We present an update on the preparation of our assets that consists of a robotic network of eight optical telescopes and a laser ranging station for regular services in the SST domain. We report the development of new optical assets that include a double telescope system, Panoptes-1AB, and a new astrograph on our Solaris-3 telescope at the Siding Spring Observatory, Australia. Progress in the software development necessary for smooth SST operation includes a web based portal and an XML Azure Queue scheduling for the network giving easy access to our sensors. Astrometry24.net our new prototype cloud service for fast astrometry, streak detection and measurement with precision and performance results is also described. In the laser domain, for more than a year, Space Research Centre Borowiec laser station has regularly tracked space debris cooperative and uncooperative targets. The efforts of the stations’ staff have been focused on the tracking of typical rocket bodies from the LEO regime. Additionally, a second independent laser system fully dedicated to SST activities is under development. It will allow for an increased pace of operation of our consortium in the global SST laser domain.

Protocol, Engineering Research Center, University of California, Santa Barbara

DTIC Science & Technology

2005-12-01

minimizing the energy consumption in idle periods. We have designed an asynchronous wakeup schedule based on the theory of block designs. The idea is...performance of ad hoc networks through innovative packet scheduling (Baker). "* Developed a number of novel schemes to ensure loop freedom in on demand routing...network nodes to schedule their transmissions to avoid collisions (Garcia-Luna-Aceves). "* Designed and analyzed the Hybrid Activation Multiple Access (HAMA

QoS Differential Scheduling in Cognitive-Radio-Based Smart Grid Networks: An Adaptive Dynamic Programming Approach.

PubMed

Yu, Rong; Zhong, Weifeng; Xie, Shengli; Zhang, Yan; Zhang, Yun

2016-02-01

As the next-generation power grid, smart grid will be integrated with a variety of novel communication technologies to support the explosive data traffic and the diverse requirements of quality of service (QoS). Cognitive radio (CR), which has the favorable ability to improve the spectrum utilization, provides an efficient and reliable solution for smart grid communications networks. In this paper, we study the QoS differential scheduling problem in the CR-based smart grid communications networks. The scheduler is responsible for managing the spectrum resources and arranging the data transmissions of smart grid users (SGUs). To guarantee the differential QoS, the SGUs are assigned to have different priorities according to their roles and their current situations in the smart grid. Based on the QoS-aware priority policy, the scheduler adjusts the channels allocation to minimize the transmission delay of SGUs. The entire transmission scheduling problem is formulated as a semi-Markov decision process and solved by the methodology of adaptive dynamic programming. A heuristic dynamic programming (HDP) architecture is established for the scheduling problem. By the online network training, the HDP can learn from the activities of primary users and SGUs, and adjust the scheduling decision to achieve the purpose of transmission delay minimization. Simulation results illustrate that the proposed priority policy ensures the low transmission delay of high priority SGUs. In addition, the emergency data transmission delay is also reduced to a significantly low level, guaranteeing the differential QoS in smart grid.

Putting ROSE to Work: A Proposed Application of a Request-Oriented Scheduling Engine for Space Station Operations

NASA Technical Reports Server (NTRS)

Jaap, John; Muery, Kim

2000-01-01

Scheduling engines are found at the core of software systems that plan and schedule activities and resources. A Request-Oriented Scheduling Engine (ROSE) is one that processes a single request (adding a task to a timeline) and then waits for another request. For the International Space Station, a robust ROSE-based system would support multiple, simultaneous users, each formulating requests (defining scheduling requirements), submitting these requests via the internet to a single scheduling engine operating on a single timeline, and immediately viewing the resulting timeline. ROSE is significantly different from the engine currently used to schedule Space Station operations. The current engine supports essentially one person at a time, with a pre-defined set of requirements from many payloads, working in either a "batch" scheduling mode or an interactive/manual scheduling mode. A planning and scheduling process that takes advantage of the features of ROSE could produce greater customer satisfaction at reduced cost and reduced flow time. This paper describes a possible ROSE-based scheduling process and identifies the additional software component required to support it. Resulting changes to the management and control of the process are also discussed.

Enabling a New Planning and Scheduling Paradigm

NASA Technical Reports Server (NTRS)

Jaap, John; Davis, Elizabeth

2004-01-01

The Flight Projects Directorate at NASA's Marshall Space Flight Center is developing a new planning and scheduling environment and a new scheduling algorithm to enable a paradigm shift in planning and scheduling concepts. Over the past 33 years Marshall has developed and evolved a paradigm for generating payload timelines for Skylab, Spacelab, various other Shuttle payloads, and the International Space Station. The current paradigm starts by collecting the requirements, called "tasks models," from the scientists and technologists for the tasks that they want to be done. Because of shortcomings in the current modeling schema, some requirements are entered as notes. Next a cadre with knowledge of vehicle and hardware modifies these models to encompass and be compatible with the hardware model; again, notes are added when the modeling schema does not provide a better way to represent the requirements. Finally, another cadre further modifies the models to be compatible with the scheduling engine. This last cadre also submits the models to the scheduling engine or builds the timeline manually to accommodate requirements that are expressed in notes. A future paradigm would provide a scheduling engine that accepts separate science models and hardware models. The modeling schema would have the capability to represent all the requirements without resorting to notes. Furthermore, the scheduling engine would not require that the models be modified to account for the capabilities (limitations) of the scheduling engine. The enabling technology under development at Marshall has three major components. (1) A new modeling schema allows expressing all the requirements of the tasks without resorting to notes or awkward contrivances. The chosen modeling schema is both maximally expressive and easy to use. It utilizes graphics methods to show hierarchies of task constraints and networks of temporal relationships. (2) A new scheduling algorithm automatically schedules the models without the intervention of a scheduling expert. The algorithm is tuned for the constraint hierarchies and the complex temporal relationships provided by the modeling schema. It has an extensive search algorithm which can exploit timing flexibilities and constraint and relationship options. (3) A web-based architecture allows multiple remote users to simultaneously model science and technology requirements and other users to model vehicle and hardware characteristics. The architecture allows the users to submit scheduling requests directly to the scheduling engine and immediately see the results. These three components are integrated so that science and technology experts with no knowledge of the vehicle or hardware subsystems and no knowledge of the internal workings of the scheduling engine have the ability to build and submit scheduling requests and see the results. The immediate feedback will hone the users' modeling skills and ultimately enable them to produce the desired timeline. This paper summarizes the three components of the enabling technology and describes how this technology would make a new paradigm possible.

Analysis of Feeder Bus Network Design and Scheduling Problems

PubMed Central

Almasi, Mohammad Hadi; Karim, Mohamed Rehan

2014-01-01

A growing concern for public transit is its inability to shift passenger's mode from private to public transport. In order to overcome this problem, a more developed feeder bus network and matched schedules will play important roles. The present paper aims to review some of the studies performed on Feeder Bus Network Design and Scheduling Problem (FNDSP) based on three distinctive parts of the FNDSP setup, namely, problem description, problem characteristics, and solution approaches. The problems consist of different subproblems including data preparation, feeder bus network design, route generation, and feeder bus scheduling. Subsequently, descriptive analysis and classification of previous works are presented to highlight the main characteristics and solution methods. Finally, some of the issues and trends for future research are identified. This paper is targeted at dealing with the FNDSP to exhibit strategic and tactical goals and also contributes to the unification of the field which might be a useful complement to the few existing reviews. PMID:24526890

A generalized network flow model for the multi-mode resource-constrained project scheduling problem with discounted cash flows

NASA Astrophysics Data System (ADS)

Chen, Miawjane; Yan, Shangyao; Wang, Sin-Siang; Liu, Chiu-Lan

2015-02-01

An effective project schedule is essential for enterprises to increase their efficiency of project execution, to maximize profit, and to minimize wastage of resources. Heuristic algorithms have been developed to efficiently solve the complicated multi-mode resource-constrained project scheduling problem with discounted cash flows (MRCPSPDCF) that characterize real problems. However, the solutions obtained in past studies have been approximate and are difficult to evaluate in terms of optimality. In this study, a generalized network flow model, embedded in a time-precedence network, is proposed to formulate the MRCPSPDCF with the payment at activity completion times. Mathematically, the model is formulated as an integer network flow problem with side constraints, which can be efficiently solved for optimality, using existing mathematical programming software. To evaluate the model performance, numerical tests are performed. The test results indicate that the model could be a useful planning tool for project scheduling in the real world.

Results of monitoring of the high orbits with ISON optical network

NASA Astrophysics Data System (ADS)

Molotov, Igor; Schildknecht, Thomas; Zalles, Rodolfo; Rumyantsev, Vasilij; Voropaev, Viktor; Zolotov, Vladimir; Kokina, Tatiana; Montojo, Francisco Javier; Namkhai, Tungalag

2016-07-01

International Scientific Optical Network (ISON) represents one of largest systems specializing in observation of space objects. ISON provides permanent monitoring of the whole GEO region, regular surveying of Molniya type orbits, and tracking of objects at GEO, GTO, HEO and LEO. ISON project is continuously developing and is joining now the 37 observation facilities in 15 countries with 79 telescopes of different class (aperture from 12.5 cm to 2.6 m). 15.4 millions measurements in 2.1 millions of tracklets for about 4100 objects are collected by KIAM in 2015. 339 new space objects have been discovered, 307 previously lost objects have been rediscovered. Telescopes of two European observatories (AIUB Zimmerwald and TFRM Barcelona) and two Latin American observatories (Bolivian Tarija and Mexican UAS Cosala) have joined to the ISON survey subsystem. New subsystem of 7 telescopes for extended GEO surveys is created (it allows KIAM to determine more precise GEO orbits for conjunction analysis). Also deployment of Roscosmos subsystem of six dedicated mini-observatories EOP-1/EOP-2 has been completed. ISON encompasses five groups of telescopes and three scheduling centers to better serve user's requests. Obtained measurements are processing at KIAM ballistic center to be used for scientific and applied goals, including collision risks analysis and space situation analysis. Achieved parameters of the above mentioned telescopes and plans of ISON network development will be presented and discussed.

Integrated coding-aware intra-ONU scheduling for passive optical networks with inter-ONU traffic

NASA Astrophysics Data System (ADS)

Li, Yan; Dai, Shifang; Wu, Weiwei

2016-12-01

Recently, with the soaring of traffic among optical network units (ONUs), network coding (NC) is becoming an appealing technique for improving the performance of passive optical networks (PONs) with such inter-ONU traffic. However, in the existed NC-based PONs, NC can only be implemented by buffering inter-ONU traffic at the optical line terminal (OLT) to wait for the establishment of coding condition, such passive uncertain waiting severely limits the effect of NC technique. In this paper, we will study integrated coding-aware intra-ONU scheduling in which the scheduling of inter-ONU traffic within each ONU will be undertaken by the OLT to actively facilitate the forming of coding inter-ONU traffic based on the global inter-ONU traffic distribution, and then the performance of PONs with inter-ONU traffic can be significantly improved. We firstly design two report message patterns and an inter-ONU traffic transmission framework as the basis for the integrated coding-aware intra-ONU scheduling. Three specific scheduling strategies are then proposed for adapting diverse global inter-ONU traffic distributions. The effectiveness of the work is finally evaluated by both theoretical analysis and simulations.

The resource envelope as a basis for space station management system scheduling

NASA Technical Reports Server (NTRS)

Bush, Joy; Critchfield, Anna

1987-01-01

The Platform Management System (PMS) Resource Envelope Scheduling System (PRESS) expert system prototype developed for space station scheduling is described. The purpose of developing the prototype was too investigate the resource envelope concept in a practical scheduling application, using a commercially available expert system shell. PRESS is being developed on an IBM PC/AT using Teknowledge, Inc.'s M.1 expert system shell.

STS-96 Crew Interview: Dan Barry

NASA Technical Reports Server (NTRS)

1999-01-01

Live footage of a preflight interview with Mission Specialist Daniel T. Barry is seen. The interview addresses many different questions including why Barry became an astronaut, and the events that led to his interest. Other interesting information that this one-on-one interview discusses is the logistics and supply mission, why it is important to send equipment to the International Space Station (ISS), and the Integrated Cargo Carrier (ICC). Barry mentions Discovery's anticipated docking with the ISS, his scheduled space walk with Tamara E. Jernigan, plans for the supply and equipment transfers, and his responsibility during this transfer. A fly-around maneuver to take pictures of the ISS, and the deployment of the Student Tracked Atmospheric Research Satellite for Heuristic International Networking Equipment (STARSHINE) are also discussed.

A Novel Approach to Noise-Filtering Based on a Gain-Scheduling Neural Network Architecture

NASA Technical Reports Server (NTRS)

Troudet, T.; Merrill, W.

1994-01-01

A gain-scheduling neural network architecture is proposed to enhance the noise-filtering efficiency of feedforward neural networks, in terms of both nominal performance and robustness. The synergistic benefits of the proposed architecture are demonstrated and discussed in the context of the noise-filtering of signals that are typically encountered in aerospace control systems. The synthesis of such a gain-scheduled neurofiltering provides the robustness of linear filtering, while preserving the nominal performance advantage of conventional nonlinear neurofiltering. Quantitative performance and robustness evaluations are provided for the signal processing of pitch rate responses to typical pilot command inputs for a modern fighter aircraft model.

143. GENERAL DYNAMICS SPACE SYSTEMS DIVISION SCHEDULE BOARD IN LUNCH ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

143. GENERAL DYNAMICS SPACE SYSTEMS DIVISION SCHEDULE BOARD IN LUNCH ROOM (120), LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Electric Vehicles Charging Scheduling Strategy Considering the Uncertainty of Photovoltaic Output

NASA Astrophysics Data System (ADS)

Wei, Xiangxiang; Su, Su; Yue, Yunli; Wang, Wei; He, Luobin; Li, Hao; Ota, Yutaka

2017-05-01

The rapid development of electric vehicles and distributed generation bring new challenges to security and economic operation of the power system, so the collaborative research of the EVs and the distributed generation have important significance in distribution network. Under this background, an EVs charging scheduling strategy considering the uncertainty of photovoltaic(PV) output is proposed. The characteristics of EVs charging are analysed first. A PV output prediction method is proposed with a PV database then. On this basis, an EVs charging scheduling strategy is proposed with the goal to satisfy EVs users’ charging willingness and decrease the power loss in distribution network. The case study proves that the proposed PV output prediction method can predict the PV output accurately and the EVs charging scheduling strategy can reduce the power loss and stabilize the fluctuation of the load in distributed network.

Work/Family Balancing and 24/7 Work Schedules: Network Analysis of Strategies in a Transport Company Cleaning Service: Concilier travail-famille et horaires 24/7: analyse réseau des stratégies au sein du service de nettoyage d'une compagnie de transport.

PubMed

Lefrançois, Mélanie; Saint-Charles, Johanne; Riel, Jessica

2017-11-01

Whether or not official work/family balance measures exist within an organization, scheduling accommodations often go through informal channels involving colleagues and superiors and are negotiated within interpersonal relationships. This study examines the relationship dimensions of the scheduling strategies of cleaners working atypical hours in the transport sector through the lenses of ergonomic activity, network, and gender analyses. Using semi-directed interviews, observation, and network analysis, we revealed the effect of gender on relationship dynamics and the influence of these dynamics on work/family balance strategies deployed by cleaners. One of the main contributions of this study is to demonstrate the decisive effect of relationships by revealing inequalities in access to organizational social networks. Creating spaces to discuss work/family balancing and a more equitable circulation of information could contribute to reducing inequalities associated with gender, social status, and family responsibilities and support the work/family strategies developed by workers dealing with restrictive work schedules. Résumé Les accommodements du temps de travail pour la conciliation travail-famille (CTF) passent souvent par des ententes informelles qui s'inscrivent dans les relations entre collègues ou avec des gestionnaires. Notre étude, intégrant l'ergonomie et la communication dans une perspective de genre, porte sur les dimensions relationnelles des stratégies de choix d'horaire d'agentes et agents de nettoyage devant composer avec des horaires atypiques dans le secteur des transports. À partir d'entretiens semi-dirigés, d'observations et d'analyse de réseaux, nous avons pu observer l'influence des dynamiques relationnelles, notamment de genre, sur les stratégies de CTF. Un apport central de cette étude est de montrer l'effet structurant des relations en révélant notamment des inégalités dans l'accès aux ressources facilitant le choix d'horaire, mais aussi dans l'inclusion au sein du réseau de relations. L'article conclut en proposant des pistes de solutions concrètes pour la réduction de ces inégalités.

Design and implementation of a UNIX based distributed computing system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Love, J.S.; Michael, M.W.

1994-12-31

We have designed, implemented, and are running a corporate-wide distributed processing batch queue on a large number of networked workstations using the UNIX{reg_sign} operating system. Atlas Wireline researchers and scientists have used the system for over a year. The large increase in available computer power has greatly reduced the time required for nuclear and electromagnetic tool modeling. Use of remote distributed computing has simultaneously reduced computation costs and increased usable computer time. The system integrates equipment from different manufacturers, using various CPU architectures, distinct operating system revisions, and even multiple processors per machine. Various differences between the machines have tomore » be accounted for in the master scheduler. These differences include shells, command sets, swap spaces, memory sizes, CPU sizes, and OS revision levels. Remote processing across a network must be performed in a manner that is seamless from the users` perspective. The system currently uses IBM RISC System/6000{reg_sign}, SPARCstation{sup TM}, HP9000s700, HP9000s800, and DEC Alpha AXP{sup TM} machines. Each CPU in the network has its own speed rating, allowed working hours, and workload parameters. The system if designed so that all of the computers in the network can be optimally scheduled without adversely impacting the primary users of the machines. The increase in the total usable computational capacity by means of distributed batch computing can change corporate computing strategy. The integration of disparate computer platforms eliminates the need to buy one type of computer for computations, another for graphics, and yet another for day-to-day operations. It might be possible, for example, to meet all research and engineering computing needs with existing networked computers.« less

An Optimal CDS Construction Algorithm with Activity Scheduling in Ad Hoc Networks

PubMed Central

Penumalli, Chakradhar; Palanichamy, Yogesh

2015-01-01

A new energy efficient optimal Connected Dominating Set (CDS) algorithm with activity scheduling for mobile ad hoc networks (MANETs) is proposed. This algorithm achieves energy efficiency by minimizing the Broadcast Storm Problem [BSP] and at the same time considering the node's remaining energy. The Connected Dominating Set is widely used as a virtual backbone or spine in mobile ad hoc networks [MANETs] or Wireless Sensor Networks [WSN]. The CDS of a graph representing a network has a significant impact on an efficient design of routing protocol in wireless networks. Here the CDS is a distributed algorithm with activity scheduling based on unit disk graph [UDG]. The node's mobility and residual energy (RE) are considered as parameters in the construction of stable optimal energy efficient CDS. The performance is evaluated at various node densities, various transmission ranges, and mobility rates. The theoretical analysis and simulation results of this algorithm are also presented which yield better results. PMID:26221627

On the Development and Application of High Data Rate Architecture (HiDRA) in Future Space Networks

NASA Technical Reports Server (NTRS)

Hylton, Alan; Raible, Daniel; Clark, Gilbert

2017-01-01

Historically, space missions have been severely constrained by their ability to downlink the data they have collected. These constraints are a result of relatively low link rates on the spacecraft as well as limitations on the time during which data can be sent. As part of a coherent strategy to address existing limitations and get more data to the ground more quickly, the Space Communications and Navigation (SCaN) program has been developing an architecture for a future solar system Internet. The High Data Rate Architecture (HiDRA) project is designed to fit into such a future SCaN network. HiDRA's goal is to describe a general packet-based networking capability which can be used to provide assets with efficient networking capabilities while simultaneously reducing the capital costs and operational costs of developing and flying future space systems.Along these lines, this paper begins by reviewing various characteristics of modern satellite design as well as relevant characteristics of emerging technologies (such as free-space optical links capable of working at 100+ Gbps). Next, the paper describes HiDRA's design, and how the system is able to both integrate and support the operation of not only today's high-rate systems, but also the high-rate systems likely to be found in the future. This section also explores both existing and future networking technologies, such as Delay Tolerant Networking (DTN) protocol (RFC4838 citeRFC:1, RFC5050citeRFC:2), and explains how HiDRA supports them. Additionally, this section explores how HiDRA is used for scheduling data movement through both proactive and reactive link management. After this, the paper moves on to explore a reference implementation of HiDRA. This implementation is currently being realized based on a Field Programmable Gate Array (FPGA) memory and interface controller that is itself controlled by a local computer running DTN software. Next, this paper explores HiDRA's natural evolution, which includes an integration path for software-defined networking (SDN) switches. This section also describes considerations for both near-Earth and deep-space instantiations of HiDRA, describing how differences in latencies between the environments will necessarily influence how the system is configured and the networks operate. Finally, this paper describes future work. This section includes a description of a potential ISS implementation which will allow rapid advancement through the technology readiness levels (TRL). This section also explores work being done to support HiDRA's successful implementation and operation in a heterogeneous network: such a network could include communications equipment spanning many vintages and capabilities, and one significant aspect of HiDRA's future development involves balancing compatibility with capability.

A Data Scheduling and Management Infrastructure for the TEAM Network

NASA Astrophysics Data System (ADS)

Andelman, S.; Baru, C.; Chandra, S.; Fegraus, E.; Lin, K.; Unwin, R.

2009-04-01

The objective of the Tropical Ecology Assessment and Monitoring Network (www.teamnetwork.org) is "To generate real time data for monitoring long-term trends in tropical biodiversity through a global network of TEAM sites (i.e. field stations in tropical forests), providing an early warning system on the status of biodiversity to effectively guide conservation action". To achieve this, the TEAM Network operates by collecting data via standardized protocols at TEAM Sites. The standardized TEAM protocols include the Climate, Vegetation and Terrestrial Vertebrate Protocols. Some sites also implement additional protocols. There are currently 7 TEAM Sites with plans to grow the network to 15 by June 30, 2009 and 50 TEAM Sites by the end of 2010. Climate Protocol The Climate Protocol entails the collection of climate data via meteorological stations located at the TEAM Sites. This includes information such as precipitation, temperature, wind direction and strength and various solar radiation measurements. Vegetation Protocol The Vegetation Protocol collects standardized information on tropical forest trees and lianas. A TEAM Site will have between 6-9 1ha plots where trees and lianas larger than a pre-specified size are mapped, identified and measured. This results in each TEAM Site repeatedly measuring between 3000-5000 trees annually. Terrestrial Vertebrate Protocol The Terrestrial Vertebrate Protocol collects standardized information on mid-sized tropical forest fauna (i.e. birds and mammals). This information is collected via camera traps (i.e. digital cameras with motion sensors housed in weather proof casings). The images taken by the camera trap are reviewed to identify what species are captured in the image by the camera trap. The image and the interpretation of what is in the image are the data for the Terrestrial Vertebrate Protocol. The amount of data collected through the TEAM protocols provides a significant yet exciting IT challenge. The TEAM Network is currently partnering with the San Diego Super Computer Center to build the data management infrastructure. Data collected from the three core protocols as well as others are currently made available through the TEAM Network portal, which provides the content management framework, the data scheduling and management framework, an administrative framework to implement and manage TEAM sites, collaborative tools and a number of tools and applications utilizing Google Map and Google Earth products. A critical element of the TEAM Network data management infrastructure is to make the data publicly available in as close to real-time as possible (the TEAM Network Data Use Policy: http://www.teamnetwork.org/en/data/policy). This requires two essential tasks to be accomplished, 1) A data collection schedule has to be planned, proposed and approved for a given TEAM site. This is a challenging process since TEAM sites are geographically distributed across the tropics and hence have different seasons where they schedule field sampling for the different TEAM protocols. Capturing this information and ensuring that TEAM sites follow the outlined legal contract is key to the data collection process and 2) A stream-lined and efficient information management system to ensure data collected from the field meet the minimum data standards (i.e. are of the highest scientific quality) and are securely transferred, archived, processed and be rapidly made publicaly available, as a finished consumable product via the TEAM Network portal. The TEAM Network is achieving these goals by implementing an end-to-end framework consisting of the Sampling Scheduler application and the Data Management Framework. Sampling Scheduler The Sampling Scheduler is a project management, calendar based portal application that will allow scientists at a TEAM site to schedule field sampling for each of the TEAM protocols implemented at that site. The sampling scheduler addresses the specific requirements established in the TEAM protocols with the logistical scheduling needs of each TEAM Site. For example, each TEAM protocol defines when data must be collected (e.g. time of day, number of times per year, during which seasons, etc) as well as where data must be collected (from which sampling units, which trees, etc). Each TEAM Site has a limited number of resources and must create plans that will both satisfy the requirements of the protocols as well as be logistically feasible for their TEAM Site. With 15 TEAM Sites (and many more coming soon) the schedules of each TEAM Site must be communicated to the Network Office to ensure data are being collected as scheduled and to address the many problems when working in difficult environments like Tropical Forests. The Sampling Schedule provides built-in proposal and approval functionality to ensure that the TEAM Sites are and the Network office are in sync as well as provides the capability to modify schedules when needed. The Data Management Framework The Data Management framework is a three-tier data ingestion, edit and review application for protocols defined in the TEAM network. The data ingestion framework provides online web forms for field personnel to submit and edit data collected at TEAM Sites. These web forms will be accessible from the TEAM content management site. Once the data is securely uploaded, cured, processed and approved, it will be made publicly available for consumption by the scientific community. The Data Management framework, when combined with the Sampling Scheduler provides a closed loop Data Scheduling and Management infrastructure. All information starting from data collection plan, tools to input, modify and curate data, review and run QA/QC tests, as well as verify data are collected as planed are included. Finally, TEAM Network data are available for download via the Data Query and Download Application. This application utilizes a Google Maps custom interface to search, visualize, and download TEAM Network data. References • TEAM Network, http://www.teamnetwork.org • Center for Applied Biodiversity Science, Conservation International. http://science.conservation.org/portal/server.pt • TEAM Data Query and Download Application, http://www.teamnetwork.org/en/data/query

Autonomous scheduling technology for Earth orbital missions

NASA Technical Reports Server (NTRS)

Srivastava, S.

1982-01-01

The development of a dynamic autonomous system (DYASS) of resources for the mission support of near-Earth NASA spacecraft is discussed and the current NASA space data system is described from a functional perspective. The future (late 80's and early 90's) NASA space data system is discussed. The DYASS concept, the autonomous process control, and the NASA space data system are introduced. Scheduling and related disciplines are surveyed. DYASS as a scheduling problem is also discussed. Artificial intelligence and knowledge representation is considered as well as the NUDGE system and the I-Space system.

CASSIUS: The Cassini Uplink Scheduler

NASA Technical Reports Server (NTRS)

Bellinger, Earl

2012-01-01

The Cassini Uplink Scheduler (CASSIUS) is cross-platform software used to generate a radiation sequence plan for commands being sent to the Cassini spacecraft. Because signals must travel through varying amounts of Earth's atmosphere, several different modes of constant telemetry rates have been devised. These modes guarantee that the spacecraft and the Deep Space Network agree with respect to the data transmission rate. However, the memory readout of a command will be lost if it occurs on a telemetry mode boundary. Given a list of spacecraft message files as well as the available telemetry modes, CASSIUS can find an uplink sequence that ensures safe transmission of each file. In addition, it can predict when the two on-board solid state recorders will swap. CASSIUS prevents data corruption by making sure that commands are not planned for memory readout during telemetry rate changes or a solid state recorder swap.

The Consolidated Planning and Scheduling System for Space Transportation and Space Station operations - Successful development experience

NASA Technical Reports Server (NTRS)

Hornstein, Rhoda S.; Willoughby, John K.; Gardner, Jo A.; Shinkle, Gerald L.

1993-01-01

In 1992, NASA made the decision to evolve a Consolidated Planning System (CPS) by adding the Space Transportation System (STS) requirements to the Space Station Freedom (SSF) planning software. This paper describes this evolutionary process, which began with a series of six-month design-build-test cycles, using a domain-independent architecture and a set of developmental tools known as the Advanced Scheduling Environment. It is shown that, during these tests, the CPS could be used at multiple organizational levels of planning and for integrating schedules from geographically distributed (including international) planning environments. The potential for using the CPS for other planning and scheduling tasks in the SSF program is being currently examined.

Sao Paulo Lightning Mapping Array (SP-LMA): Deployment and Plans

NASA Technical Reports Server (NTRS)

Bailey, J. C.; Carey, L. D.; Blakeslee, R. J.; Albrecht, R.; Morales, C. A.; Pinto, O., Jr.

2011-01-01

An 8-10 station Lightning Mapping Array (LMA) network is being deployed in the vicinity of Sao Paulo to create the SP-LMA for total lightning measurements in association with the international CHUVA [Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)] field campaign. Besides supporting CHUVA science/mission objectives and the Sao Luz Paraitinga intensive operation period (IOP) in December 2011-January 2012, the SP-LMA will support the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), both sensors on the NOAA Geostationary Operational Environmental Satellite-R (GOES-R), presently under development and scheduled for a 2015 launch. The proxy data will be used to develop and validate operational algorithms so that they will be ready for use on "day1" following the launch of GOES-R. A preliminary survey of potential sites in the vicinity of Sao Paulo was conducted in December 2009 and January 2010, followed up by a detailed survey in July 2010, with initial network deployment scheduled for October 2010. However, due to a delay in the Sa Luz Paraitinga IOP, the SP-LMA will now be installed in July 2011 and operated for one year. Spacing between stations is on the order of 15-30 km, with the network "diameter" being on the order of 30-40 km, which provides good 3-D lightning mapping 150 km from the network center. Optionally, 1-3 additional stations may be deployed in the vicinity of Sa Jos dos Campos.

Sao Paulo Lightning Mapping Array (SP-LMA): Deployment, Operation and Initial Data Analysis

NASA Technical Reports Server (NTRS)

Blakeslee, R.; Bailey, J. C.; Carey, L. D.; Rudlosky, S.; Goodman, S. J.; Albrecht, R.; Morales, C. A.; Anseimo, E. M.; Pinto, O.

2012-01-01

An 8-10 station Lightning Mapping Array (LMA) network is being deployed in the vicinity of Sao Paulo to create the SP-LMA for total lightning measurements in association with the international CHUVA [Cloud processes of the main precipitation systems in Brazil: A contribution to cloud resolving modeling and to the GPM (Global Precipitation Measurement)] field campaign. Besides supporting CHUVA science/mission objectives and the Sao Luiz do Paraitinga intensive operation period (IOP) in November-December 2011, the SP-LMA will support the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), both sensors on the NOAA Geostationary Operational Environmental Satellite-R (GOES-R), presently under development and scheduled for a 2015 launch. The proxy data will be used to develop and validate operational algorithms so that they will be ready for use on "day1" following the launch of GOES-R. A preliminary survey of potential sites in the vicinity of Sao Paulo was conducted in December 2009 and January 2010, followed up by a detailed survey in July 2010, with initial network deployment scheduled for October 2010. However, due to a delay in the Sao Luiz do Paraitinga IOP, the SP-LMA will now be installed in July 2011 and operated for one year. Spacing between stations is on the order of 15-30 km, with the network "diameter" being on the order of 30-40 km, which provides good 3-D lightning mapping 150 km from the network center. Optionally, 1-3 additional stations may be deployed in the vicinity of Sao Jos dos Campos.

Distributed Signal Processing in Wireless Sensor Networks

DTIC Science & Technology

2005-08-01

in sensor networks. Previous endeavors focused on how to schedule trackers to go to sleep or to wake up trackers based on detection outcomes. On the...one hand, all nodes wake up according to a predefined schedule so that only involved nodes are kept active for the exact duration of a task execution...Recently a new MAC - S-MAC [70] has been proposed, and it enables nodes to sleep not only for a scheduled period, but also for other periods for which

Challenges and Lessons Learned in the Application of Autonomy to Space Operations

NASA Technical Reports Server (NTRS)

Forrest, David J.

2001-01-01

NASA's Space Operations Management Office (SOMO) is working toward a goal of providing an integrated infrastructure of mission and data services for space missions undertaken by NASA enterprises. A significant portion of this effort is focused on reducing the cost of these services. We are interested in the potential of autonomy to reduce operations costs. SOMO services support space missions, but are not part of the mission objectives; therefore the level of acceptable risk is very low. In fact, SOMO could be effective ly prevented from applying autonomy if customers merely perceive it as adding risk to their mission(s). We are interested in this workshop from the standpoint of understanding what can be done to realize the potential cost savings due to autonomy while maintaining acceptable risk and serving the needs of our customers. We would like to present our lessons learned so far in adopting autonomy and automation, which we think will contribute to clarifying the challenges facing the use of such technology. SOMO provides services to a diverse and ambitious set of mission customers. Many of these missions are groundbreaking missions for which communications, data, and other operations requirements sometimes cannot be clearly articulated early in the program. This motivates a need for systems that are robust in the face of unanticipated situations so that customer missions are not unreasonably constrained or impacted by "shortcomings" in SOMO services. One of SOMO's primary goals is to realize a paradigm in which SOMO acts as a service provider to organizations that fly space missions for NASA, other government agencies, and even the commercial sector. These organizations purchase SOMO services "by the pound" as customers. We have to provide systems that are not experiments themselves, but rather stable bases from which to do bold experiments. To this end, SOMO also seeks to work closely with industry to see that robust autonomy technology gets infused into products and services for the space industry and beyond. The potential for application of these technologies spans space-based communications networks (e.g. TDRSS) and ground-based assets including communication and tracking antenna systems, data networks, and control centers. There are several problems that are candidates for the application of autonomy, if it can be made reliable enough, including: antenna control, antenna scheduling, communication link scheduling and operation, navigation, attitude determination, fault detection, isolation, and reconfiguration (for spacecraft or ground assets), and mission-level planning and scheduling. Some attempts have been made to apply autonomy and automation in these areas in the past with varying degrees of success. We will present relevant case histories and the lessons inferred from them. Combining this past experience with anticipated future needs, we can clarify the challenges that must be met in order to realize the benefits of autonomy.

Coordinating space telescope operations in an integrated planning and scheduling architecture

NASA Technical Reports Server (NTRS)

Muscettola, Nicola; Smith, Stephen F.; Cesta, Amedeo; D'Aloisi, Daniela

1992-01-01

The Heuristic Scheduling Testbed System (HSTS), a software architecture for integrated planning and scheduling, is discussed. The architecture has been applied to the problem of generating observation schedules for the Hubble Space Telescope. This problem is representative of the class of problems that can be addressed: their complexity lies in the interaction of resource allocation and auxiliary task expansion. The architecture deals with this interaction by viewing planning and scheduling as two complementary aspects of the more general process of constructing behaviors of a dynamical system. The principal components of the software architecture are described, indicating how to model the structure and dynamics of a system, how to represent schedules at multiple levels of abstraction in the temporal database, and how the problem solving machinery operates. A scheduler for the detailed management of Hubble Space Telescope operations that has been developed within HSTS is described. Experimental performance results are given that indicate the utility and practicality of the approach.

Software defined multi-OLT passive optical network for flexible traffic allocation

NASA Astrophysics Data System (ADS)

Zhang, Shizong; Gu, Rentao; Ji, Yuefeng; Zhang, Jiawei; Li, Hui

2016-10-01

With the rapid growth of 4G mobile network and vehicular network services mobile terminal users have increasing demand on data sharing among different radio remote units (RRUs) and roadside units (RSUs). Meanwhile, commercial video-streaming, video/voice conference applications delivered through peer-to-peer (P2P) technology are still keep on stimulating the sharp increment of bandwidth demand in both business and residential subscribers. However, a significant issue is that, although wavelength division multiplexing (WDM) and orthogonal frequency division multiplexing (OFDM) technology have been proposed to fulfil the ever-increasing bandwidth demand in access network, the bandwidth of optical fiber is not unlimited due to the restriction of optical component properties and modulation/demodulation technology, and blindly increase the wavelength cannot meet the cost-sensitive characteristic of the access network. In this paper, we propose a software defined multi-OLT PON architecture to support efficient scheduling of access network traffic. By introducing software defined networking technology and wavelength selective switch into TWDM PON system in central office, multiple OLTs can be considered as a bandwidth resource pool and support flexible traffic allocation for optical network units (ONUs). Moreover, under the configuration of the control plane, ONUs have the capability of changing affiliation between different OLTs under different traffic situations, thus the inter-OLT traffic can be localized and the data exchange pressure of the core network can be released. Considering this architecture is designed to be maximum following the TWDM PON specification, the existing optical distribution network (ODN) investment can be saved and conventional EPON/GPON equipment can be compatible with the proposed architecture. What's more, based on this architecture, we propose a dynamic wavelength scheduling algorithm, which can be deployed as an application on control plane and achieve effective scheduling OLT wavelength resources between different OLTs based on various traffic situation. Simulation results show that, by using the scheduling algorithm, network traffic between different OLTs can be optimized effectively, and the wavelength utilization of the multi-OLT system can be improved due to the flexible wavelength scheduling.

Highly automated on-orbit operations of the NuSTAR telescope

NASA Astrophysics Data System (ADS)

Roberts, Bryce; Bester, Manfred; Dumlao, Renee; Eckert, Marty; Johnson, Sam; Lewis, Mark; McDonald, John; Pease, Deron; Picard, Greg; Thorsness, Jeremy

2014-08-01

UC Berkeley's Space Sciences Laboratory (SSL) currently operates a fleet of seven NASA satellites, which conduct research in the fields of space physics and astronomy. The newest addition to this fleet is a high-energy X-ray telescope called the Nuclear Spectroscopic Telescope Array (NuSTAR). Since 2012, SSL has conducted on-orbit operations for NuSTAR on behalf of the lead institution, principle investigator, and Science Operations Center at the California Institute of Technology. NuSTAR operations benefit from a truly multi-mission ground system architecture design focused on automation and autonomy that has been honed by over a decade of continual improvement and ground network expansion. This architecture has made flight operations possible with nominal 40 hours per week staffing, while not compromising mission safety. The remote NuSTAR Science Operation Center (SOC) and Mission Operations Center (MOC) are joined by a two-way electronic interface that allows the SOC to submit automatically validated telescope pointing requests, and also to receive raw data products that are automatically produced after downlink. Command loads are built and uploaded weekly, and a web-based timeline allows both the SOC and MOC to monitor the state of currently scheduled spacecraft activities. Network routing and the command and control system are fully automated by MOC's central scheduling system. A closed-loop data accounting system automatically detects and retransmits data gaps. All passes are monitored by two independent paging systems, which alert staff of pass support problems or anomalous telemetry. NuSTAR mission operations now require less than one attended pass support per workday.

Path Flow Estimation Using Time Varying Coefficient State Space Model

NASA Astrophysics Data System (ADS)

Jou, Yow-Jen; Lan, Chien-Lun

2009-08-01

The dynamic path flow information is very crucial in the field of transportation operation and management, i.e., dynamic traffic assignment, scheduling plan, and signal timing. Time-dependent path information, which is important in many aspects, is nearly impossible to be obtained. Consequently, researchers have been seeking estimation methods for deriving valuable path flow information from less expensive traffic data, primarily link traffic counts of surveillance systems. This investigation considers a path flow estimation problem involving the time varying coefficient state space model, Gibbs sampler, and Kalman filter. Numerical examples with part of a real network of the Taipei Mass Rapid Transit with real O-D matrices is demonstrated to address the accuracy of proposed model. Results of this study show that this time-varying coefficient state space model is very effective in the estimation of path flow compared to time-invariant model.

KSC-2009-4592

NASA Image and Video Library

2009-08-11

CAPE CANAVERAL, Fla. – At the Astrotech Space Operations facility in Titusville, Fla., workers in the control room monitor the data on computer screens from the movement of the high-gain antenna on the Solar Dynamics Observatory, or SDO. The SDO is undergoing performance testing. All of the spacecraft science instruments are being tested in their last major evaluation before launch. SDO is the first space weather research network mission in NASA's Living With a Star Program. The spacecraft's long-term measurements will give solar scientists in-depth information about changes in the sun's magnetic field and insight into how they affect Earth. In preparation for launch, engineers will perform a battery of comprehensive tests to ensure SDO can withstand the stresses and vibrations of the launch itself, as well as what it will encounter in the space environment after launch. Liftoff on an Atlas V rocket is scheduled for Dec. 4. Photo credit: NASA/Jack Pfaller

KSC-2010-5377

NASA Image and Video Library

2010-11-01

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, NASA Public Affairs Officer John Yembrick welcomes participants to the STS-133 Tweetup. NASA is hosting about 150 of its Twitter followers from around the world and several dozen states and providing them with a behind-the-scenes perspective to share with their own followers on the social networking service. The "Tweeps," as NASA calls them, will have a chance to tour Kennedy and meet with shuttle technicians, managers, engineers and astronauts. They also will receive a demonstration of Robonaut, a human-like robot similar to the one that will be delivered to the International Space Station on the STS-133 mission. Space shuttle Discovery and its STS-133 crew are scheduled to launch Nov. 3 at 3:52 p.m. EDT. For more information on the upcoming mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

KSC-2010-5382

NASA Image and Video Library

2010-11-01

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, NASA astronaut Ron Garan addresses participants of the STS-133 Tweetup. NASA is hosting about 150 of its Twitter followers from around the world and several dozen states and providing them with a behind-the-scenes perspective to share with their own followers on the social networking service. The "Tweeps," as NASA calls them, will have a chance to tour Kennedy and meet with shuttle technicians, managers, engineers and astronauts. They also will receive a demonstration of Robonaut, a human-like robot similar to the one that will be delivered to the International Space Station on the STS-133 mission. Space shuttle Discovery and its STS-133 crew are scheduled to launch Nov. 3 at 3:52 p.m. EDT. For more information on the upcoming mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

KSC-2010-5376

NASA Image and Video Library

2010-11-01

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, NASA Public Affairs Officer John Yembrick welcomes participants to the STS-133 Tweetup. NASA is hosting about 150 of its Twitter followers from around the world and several dozen states and providing them with a behind-the-scenes perspective to share with their own followers on the social networking service. The "Tweeps," as NASA calls them, will have a chance to tour Kennedy and meet with shuttle technicians, managers, engineers and astronauts. They also will receive a demonstration of Robonaut, a human-like robot similar to the one that will be delivered to the International Space Station on the STS-133 mission. Space shuttle Discovery and its STS-133 crew are scheduled to launch Nov. 3 at 3:52 p.m. EDT. For more information on the upcoming mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

KSC-04PD-2670

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Workers at Astrotech Space Operations in Titusville, Fla., get ready to begin fueling the Deep Impact spacecraft, seen wrapped in a protective cover in the background. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-04PD-2673

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Workers at Astrotech Space Operations in Titusville, Fla., begin fueling operations of the Deep Impact spacecraft, seen wrapped in a protective cover in the background. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-04PD-2674

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Workers at Astrotech Space Operations in Titusville, Fla., begin fueling operations of the Deep Impact spacecraft, seen wrapped in a protective cover in the background. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0128

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. On Launch Pad 17-B, Cape Canaveral Air Force Station, Fla., the Boeing Delta II rocket carrying the Deep Impact spacecraft stands out against an early dawn sky. Scheduled for liftoff at 1:47 p.m. EST today, Deep Impact will head for space and a rendezvous with Comet Tempel 1 when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile (impactor) to crash onto the surface July 4, 2005, Deep Impacts flyby spacecraft will reveal the secrets of the comets interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0124

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. On Launch Pad 17-B, Cape Canaveral Air Force Station, Fla., the Boeing Delta II rocket carrying the Deep Impact spacecraft is bathed in light waiting for tower rollback before launch. Scheduled for liftoff at 1:47 p.m. EST today, Deep Impact will head for space and a rendezvous with Comet Tempel 1 when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile (impactor) to crash onto the surface July 4, 2005, Deep Impacts flyby spacecraft will reveal the secrets of the comets interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-04PD-2671

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. Workers at Astrotech Space Operations in Titusville, Fla., get ready to begin fueling the Deep Impact spacecraft, seen wrapped in a protective cover in the background. Scheduled for liftoff Jan. 12, Deep Impact will probe beneath the surface of Comet Tempel 1 on July 4, 2005, when the comet is 83 million miles from Earth, and reveal the secrets of its interior. After releasing a 3- by 3-foot projectile to crash onto the surface, Deep Impacts flyby spacecraft will collect pictures and data of how the crater forms, measuring the craters depth and diameter, as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

Space station payload operations scheduling with ESP2

NASA Technical Reports Server (NTRS)

Stacy, Kenneth L.; Jaap, John P.

1988-01-01

The Mission Analysis Division of the Systems Analysis and Integration Laboratory at the Marshall Space Flight Center is developing a system of programs to handle all aspects of scheduling payload operations for Space Station. The Expert Scheduling Program (ESP2) is the heart of this system. The task of payload operations scheduling can be simply stated as positioning the payload activities in a mission so that they collect their desired data without interfering with other activities or violating mission constraints. ESP2 is an advanced version of the Experiment Scheduling Program (ESP) which was developed by the Mission Integration Branch beginning in 1979 to schedule Spacelab payload activities. The automatic scheduler in ESP2 is an expert system that embodies the rules that expert planners would use to schedule payload operations by hand. This scheduler uses depth-first searching, backtracking, and forward chaining techniques to place an activity so that constraints (such as crew, resources, and orbit opportunities) are not violated. It has an explanation facility to show why an activity was or was not scheduled at a certain time. The ESP2 user can also place the activities in the schedule manually. The program offers graphical assistance to the user and will advise when constraints are being violated. ESP2 also has an option to identify conflict introduced into an existing schedule by changes to payload requirements, mission constraints, and orbit opportunities.

A hybrid online scheduling mechanism with revision and progressive techniques for autonomous Earth observation satellite

NASA Astrophysics Data System (ADS)

Li, Guoliang; Xing, Lining; Chen, Yingwu

2017-11-01

The autonomicity of self-scheduling on Earth observation satellite and the increasing scale of satellite network attract much attention from researchers in the last decades. In reality, the limited onboard computational resource presents challenge for the online scheduling algorithm. This study considered online scheduling problem for a single autonomous Earth observation satellite within satellite network environment. It especially addressed that the urgent tasks arrive stochastically during the scheduling horizon. We described the problem and proposed a hybrid online scheduling mechanism with revision and progressive techniques to solve this problem. The mechanism includes two decision policies, a when-to-schedule policy combining periodic scheduling and critical cumulative number-based event-driven rescheduling, and a how-to-schedule policy combining progressive and revision approaches to accommodate two categories of task: normal tasks and urgent tasks. Thus, we developed two heuristic (re)scheduling algorithms and compared them with other generally used techniques. Computational experiments indicated that the into-scheduling percentage of urgent tasks in the proposed mechanism is much higher than that in periodic scheduling mechanism, and the specific performance is highly dependent on some mechanism-relevant and task-relevant factors. For the online scheduling, the modified weighted shortest imaging time first and dynamic profit system benefit heuristics outperformed the others on total profit and the percentage of successfully scheduled urgent tasks.

Time-optimum packet scheduling for many-to-one routing in wireless sensor networks

USGS Publications Warehouse

Song, W.-Z.; Yuan, F.; LaHuser, R.

2007-01-01

This paper studies the WSN application scenario with periodical traffic from all sensors to a sink. We present a time-optimum and energy-efficient packet scheduling algorithm and its distributed implementation. We first give a general many-to-one packet scheduling algorithm for wireless networks, and then prove that it is time-optimum and costs max(2N(u1) - 1, N(u 0) -1) time slots, assuming each node reports one unit of data in each round. Here N(u0) is the total number of sensors, while N(u 1) denotes the number of sensors in a sink's largest branch subtree. With a few adjustments, we then show that our algorithm also achieves time-optimum scheduling in heterogeneous scenarios, where each sensor reports a heterogeneous amount of data in each round. Then we give a distributed implementation to let each node calculate its duty-cycle locally and maximize efficiency globally. In this packet scheduling algorithm, each node goes to sleep whenever it is not transceiving, so that the energy waste of idle listening is also eliminated. Finally, simulations are conducted to evaluate network performance using the Qualnet simulator. Among other contributions, our study also identifies the maximum reporting frequency that a deployed sensor network can handle. ??2006 IEEE.

Contribution of Schedule Delays to Cost Growth: How to Make Peace with a Marching Army

NASA Technical Reports Server (NTRS)

Majerowicz, Walt; Bitten, Robert; Emmons, Debra; Shinn, Stephen A.

2016-01-01

Numerous research papers have shown that cost and schedule growth are interrelated for NASA space science missions. Although there has shown to be a strong correlation of cost growth with schedule growth, it is unclear what percentage of cost growth is caused by schedule growth and how schedule growth can be controlled. This paper attempts to quantify this percentage by looking at historical data and show detailed examples of how schedule growth influences cost growth. The paper also addresses a methodology to show an alternate approach for assessing and setting a robust baseline schedule and use schedule performance metrics to help assess if the project is performing to plan. Finally, recommendations are presented to help control schedule growth in order to minimize cost growth for NASA space science missions.

Using Satellite Imagery with ET Weather Station Networks to Map Crop Water Use for Irrigation Scheduling: TOPS-SIMS.

USDA-ARS?s Scientific Manuscript database

Evapotranspiration estimates for scheduling irrigation must be field specific and real time. Weather station networks provide daily reference ET values, but users need to select crop coefficients for their particular crop and field. A prototype system has been developed that combines satellite image...

Energy-saving framework for passive optical networks with ONU sleep/doze mode.

PubMed

Van, Dung Pham; Valcarenghi, Luca; Dias, Maluge Pubuduni Imali; Kondepu, Koteswararao; Castoldi, Piero; Wong, Elaine

2015-02-09

This paper proposes an energy-saving passive optical network framework (ESPON) that aims to incorporate optical network unit (ONU) sleep/doze mode into dynamic bandwidth allocation (DBA) algorithms to reduce ONU energy consumption. In the ESPON, the optical line terminal (OLT) schedules both downstream (DS) and upstream (US) transmissions in the same slot in an online and dynamic fashion whereas the ONU enters sleep mode outside the slot. The ONU sleep time is maximized based on both DS and US traffic. Moreover, during the slot, the ONU might enter doze mode when only its transmitter is idle to further improve energy efficiency. The scheduling order of data transmission, control message exchange, sleep period, and doze period defines an energy-efficient scheme under the ESPON. Three schemes are designed and evaluated in an extensive FPGA-based evaluation. Results show that whilst all the schemes significantly save ONU energy for different evaluation scenarios, the scheduling order has great impact on their performance. In addition, the ESPON allows for a scheduling order that saves ONU energy independently of the network reach.

A cross-domain communication resource scheduling method for grid-enabled communication networks

NASA Astrophysics Data System (ADS)

Zheng, Xiangquan; Wen, Xiang; Zhang, Yongding

2011-10-01

To support a wide range of different grid applications in environments where various heterogeneous communication networks coexist, it is important to enable advanced capabilities in on-demand and dynamical integration and efficient co-share with cross-domain heterogeneous communication resource, thus providing communication services which are impossible for single communication resource to afford. Based on plug-and-play co-share and soft integration with communication resource, Grid-enabled communication network is flexibly built up to provide on-demand communication services for gird applications with various requirements on quality of service. Based on the analysis of joint job and communication resource scheduling in grid-enabled communication networks (GECN), this paper presents a cross multi-domain communication resource cooperatively scheduling method and describes the main processes such as traffic requirement resolution for communication services, cross multi-domain negotiation on communication resource, on-demand communication resource scheduling, and so on. The presented method is to afford communication service capability to cross-domain traffic delivery in GECNs. Further research work towards validation and implement of the presented method is pointed out at last.

Mixed Criticality Scheduling for Industrial Wireless Sensor Networks

PubMed Central

Jin, Xi; Xia, Changqing; Xu, Huiting; Wang, Jintao; Zeng, Peng

2016-01-01

Wireless sensor networks (WSNs) have been widely used in industrial systems. Their real-time performance and reliability are fundamental to industrial production. Many works have studied the two aspects, but only focus on single criticality WSNs. Mixed criticality requirements exist in many advanced applications in which different data flows have different levels of importance (or criticality). In this paper, first, we propose a scheduling algorithm, which guarantees the real-time performance and reliability requirements of data flows with different levels of criticality. The algorithm supports centralized optimization and adaptive adjustment. It is able to improve both the scheduling performance and flexibility. Then, we provide the schedulability test through rigorous theoretical analysis. We conduct extensive simulations, and the results demonstrate that the proposed scheduling algorithm and analysis significantly outperform existing ones. PMID:27589741

Energy Efficient Cluster Based Scheduling Scheme for Wireless Sensor Networks

PubMed Central

Srie Vidhya Janani, E.; Ganesh Kumar, P.

2015-01-01

The energy utilization of sensor nodes in large scale wireless sensor network points out the crucial need for scalable and energy efficient clustering protocols. Since sensor nodes usually operate on batteries, the maximum utility of network is greatly dependent on ideal usage of energy leftover in these sensor nodes. In this paper, we propose an Energy Efficient Cluster Based Scheduling Scheme for wireless sensor networks that balances the sensor network lifetime and energy efficiency. In the first phase of our proposed scheme, cluster topology is discovered and cluster head is chosen based on remaining energy level. The cluster head monitors the network energy threshold value to identify the energy drain rate of all its cluster members. In the second phase, scheduling algorithm is presented to allocate time slots to cluster member data packets. Here congestion occurrence is totally avoided. In the third phase, energy consumption model is proposed to maintain maximum residual energy level across the network. Moreover, we also propose a new packet format which is given to all cluster member nodes. The simulation results prove that the proposed scheme greatly contributes to maximum network lifetime, high energy, reduced overhead, and maximum delivery ratio. PMID:26495417

CRI planning and scheduling for space

NASA Technical Reports Server (NTRS)

Aarup, Mads

1994-01-01

Computer Resources International (CRI) has many years of experience in developing space planning and scheduling systems for the European Space Agency. Activities range from AIT/AIV planning over mission planning to research in on-board autonomy using advanced planning and scheduling technologies in conjunction with model based diagnostics. This article presents four projects carried out for ESA by CRI with various subcontractors: (1) DI, Distributed Intelligence for Ground/Space Systems is an on-going research project; (2) GMPT, Generic Mission Planning Toolset, a feasibility study concluded in 1993; (3) OPTIMUM-AIV, Open Planning Tool for AIV, development of a knowledge based AIV planning and scheduling tool ended in 1992; and (4) PlanERS-1, development of an AI and knowledge-based mission planning prototype for the ERS-1 earth observation spacecraft ended in 1991.

TDRS-L Media Day

NASA Image and Video Library

2014-01-03

TITUSVILLE, Fla. – Members of the news media are given an up-close look at the Tracking and Data Relay Satellite, or TDRS-L, spacecraft undergoing preflight processing inside the Astrotech payload processing facility in Titusville. TDRS-L is being prepared for encapsulation inside its payload fairing prior to being transported to Launch Complex 41 at Cape Canaveral Air Force Station. Journalists visited Astrotech as part of TDRS-L Media Day to conduct interviews and photograph the satellite that will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

MPLMs viewed in SSPF

NASA Technical Reports Server (NTRS)

2000-01-01

In the Space Station Processing Facility sit Raffaello (left) and Leonardo (right), two Multi-Purpose Logistics Modules (MPLMs) built by Italy for the International Space Station. Leonardo is scheduled on mission STS-102, the 8th flight to the Space Station early in 2001. Raffaello is scheduled on mission STS-100, the 9th flight to the Space Station in 2001.

Range Scheduling Aid (RSA)

NASA Technical Reports Server (NTRS)

Logan, J. R.; Pulvermacher, M. K.

1991-01-01

Range Scheduling Aid (RSA) is presented in the form of the viewgraphs. The following subject areas are covered: satellite control network; current and new approaches to range scheduling; MITRE tasking; RSA features; RSA display; constraint based analytic capability; RSA architecture; and RSA benefits.

Future aircraft networks and schedules

NASA Astrophysics Data System (ADS)

Shu, Yan

2011-07-01

Because of the importance of air transportation scheduling, the emergence of small aircraft and the vision of future fuel-efficient aircraft, this thesis has focused on the study of aircraft scheduling and network design involving multiple types of aircraft and flight services. It develops models and solution algorithms for the schedule design problem and analyzes the computational results. First, based on the current development of small aircraft and on-demand flight services, this thesis expands a business model for integrating on-demand flight services with the traditional scheduled flight services. This thesis proposes a three-step approach to the design of aircraft schedules and networks from scratch under the model. In the first step, both a frequency assignment model for scheduled flights that incorporates a passenger path choice model and a frequency assignment model for on-demand flights that incorporates a passenger mode choice model are created. In the second step, a rough fleet assignment model that determines a set of flight legs, each of which is assigned an aircraft type and a rough departure time is constructed. In the third step, a timetable model that determines an exact departure time for each flight leg is developed. Based on the models proposed in the three steps, this thesis creates schedule design instances that involve almost all the major airports and markets in the United States. The instances of the frequency assignment model created in this thesis are large-scale non-convex mixed-integer programming problems, and this dissertation develops an overall network structure and proposes iterative algorithms for solving these instances. The instances of both the rough fleet assignment model and the timetable model created in this thesis are large-scale mixed-integer programming problems, and this dissertation develops subproblem schemes for solving these instances. Based on these solution algorithms, this dissertation also presents computational results of these large-scale instances. To validate the models and solution algorithms developed, this thesis also compares the daily flight schedules that it designs with the schedules of the existing airlines. Furthermore, it creates instances that represent different economic and fuel-prices conditions and derives schedules under these different conditions. In addition, it discusses the implication of using new aircraft in the future flight schedules. Finally, future research in three areas---model, computational method, and simulation for validation---is proposed.

KSC-2013-3560

NASA Image and Video Library

2013-09-11

CAPE CANAVERAL, Fla. – At NASA's Kennedy Space Center in Florida, engineers are running tests between the Mars Atmosphere and Volatile Evolution, or MAVEN, spacecraft and MIL-71. The control room is the Kennedy interface with the Deep Space Network, or DSN. This compatibility test with MAVEN will verify that the spacecraft will be able to relay data back through the DSN interfaces during its mission to the Red Planet. MAVEN is being prepared for its scheduled launch in November from Cape Canaveral Air Force Station, Fla. atop a United Launch Alliance Atlas V rocket. Positioned in an orbit above the Red Planet, MAVEN will study the upper atmosphere of Mars in unprecedented detail. For more information, visit: http://www.nasa.gov/mission_pages/maven/main/index.html Photo credit: NASA/Jim Grossmann

A development of logistics management models for the Space Transportation System

NASA Technical Reports Server (NTRS)

Carrillo, M. J.; Jacobsen, S. E.; Abell, J. B.; Lippiatt, T. F.

1983-01-01

A new analytic queueing approach was described which relates stockage levels, repair level decisions, and the project network schedule of prelaunch operations directly to the probability distribution of the space transportation system launch delay. Finite source population and limited repair capability were additional factors included in this logistics management model developed specifically for STS maintenance requirements. Data presently available to support logistics decisions were based on a comparability study of heavy aircraft components. A two-phase program is recommended by which NASA would implement an integrated data collection system, assemble logistics data from previous STS flights, revise extant logistics planning and resource requirement parameters using Bayes-Lin techniques, and adjust for uncertainty surrounding logistics systems performance parameters. The implementation of these recommendations can be expected to deliver more cost-effective logistics support.

14 CFR 1215.109 - Scheduling user service.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Scheduling user service. 1215.109 Section 1215.109 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION TRACKING AND DATA RELAY... highest priority: (i) Launch, reentry, landing of the STS Shuttle, or other NASA launches. (ii) NASA...

14 CFR 1215.109 - Scheduling user service.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Scheduling user service. 1215.109 Section 1215.109 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION TRACKING AND DATA RELAY... highest priority: (i) Launch, reentry, landing of the STS Shuttle, or other NASA launches. (ii) NASA...

14 CFR 1215.109 - Scheduling user service.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Scheduling user service. 1215.109 Section 1215.109 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION TRACKING AND DATA RELAY... highest priority: (i) Launch, reentry, landing of the STS Shuttle, or other NASA launches. (ii) NASA...

Synchronization in neural nets

NASA Technical Reports Server (NTRS)

Vidal, Jacques J.; Haggerty, John

1988-01-01

The paper presents an artificial neural network concept (the Synchronizable Oscillator Networks) where the instants of individual firings in the form of point processes constitute the only form of information transmitted between joining neurons. In the model, neurons fire spontaneously and regularly in the absence of perturbation. When interaction is present, the scheduled firings are advanced or delayed by the firing of neighboring neurons. Networks of such neurons become global oscillators which exhibit multiple synchronizing attractors. From arbitrary initial states, energy minimization learning procedures can make the network converge to oscillatory modes that satisfy multi-dimensional constraints. Such networks can directly represent routing and scheduling problems that consist of ordering sequences of events.

A human factors approach to range scheduling for satellite control

NASA Technical Reports Server (NTRS)

Wright, Cameron H. G.; Aitken, Donald J.

1991-01-01

Range scheduling for satellite control presents a classical problem: supervisory control of a large-scale dynamic system, with unwieldy amounts of interrelated data used as inputs to the decision process. Increased automation of the task, with the appropriate human-computer interface, is highly desirable. The development and user evaluation of a semi-automated network range scheduling system is described. The system incorporates a synergistic human-computer interface consisting of a large screen color display, voice input/output, a 'sonic pen' pointing device, a touchscreen color CRT, and a standard keyboard. From a human factors standpoint, this development represents the first major improvement in almost 30 years to the satellite control network scheduling task.

Commercial Network Television: Strategies for Programming and the Content of Prime Time TV, 1976-1979.

ERIC Educational Resources Information Center

Austin, Bruce A.

The 1976-79 schedules of the three major television networks were analyzed to determine what strategies were used to organize prime time schedules and what types of programs appeared during prime time viewing periods. Five essential programing strategies were identified: fraction of selection (cost versus reward), lowest common denominator (wide…

Global Precipitation Measurement (GPM) Mission

NASA Image and Video Library

2014-02-26

Chief officers from Mitsubishi Heavy Industries, Ltd., the Japan Aerospace Exploration Agency (JAXA) and NASA met on Wednesday, Feb. 26, 2014 in the Range Control Center (RCC) of the Tanegashima Space Center, Japan, to review the readiness of the Global Precipitation Measurement (GPM) Core Observatory for launch. The spacecraft is scheduled to launch aboard an H-IIA rocket early on the morning of Feb. 28 Japan time. Once launched, the GPM spacecraft will collect information that unifies data from an international network of existing and future satellites to map global rainfall and snowfall every three hours. Photo Credit: (NASA/Bill Ingalls)

Global Precipitation Measurement (GPM) Mission

NASA Image and Video Library

2014-02-22

A roadside sign shows visitors of Minamitane Town various locations for activities, including the viewing of rocket launches from the Japan Aerospace Exploration Agency’s (JAXA) Tanegashima Space Center (TNSC), where the launch of an H-IIA rocket carrying the Global Precipitation Measurement (GPM) Core Observatory is scheduled to take place in the next week, Saturday, Feb. 22, 2014, Minamitane Town, Tanegashima Island, Japan. The NASA-JAXA GPM spacecraft will collect information that unifies data from an international network of existing and future satellites to map global rainfall and snowfall every three hours. Launch is planned for Feb. 28, 2014. Photo Credit: (NASA/Bill Ingalls)

Technicians complete foaming around Atlantis', OV-104, 17" ET feed line

NASA Image and Video Library

1990-07-10

Technicians complete foaming around the area of Atlantis, Orbiter Vehicle (OV) 104, 17 inch diameter external tank (ET) feed line in preparation for the second liquid hydrogen tanking test at the Kennedy Space Center (KSC). An elaborate network of sensors, leak detectors, and baggies were set up on OV-104 by technicians. Engineers hope this extra instrumentation will help pinpoint the exact location of the leak. OV-104 is scheduled to be launched for the STS-38 mission, a classified Department of Defense (DOD) flight. View provided by KSC with alternate number KSC-90PC-988.

Technicians complete foaming around Atlantis', OV-104, 17' ET feed line

NASA Technical Reports Server (NTRS)

1990-01-01

Technicians complete foaming around the area of Atlantis, Orbiter Vehicle (OV) 104, 17 inch diameter external tank (ET) feed line in preparation for the second liquid hydrogen tanking test at the Kennedy Space Center (KSC). An elaborate network of sensors, leak detectors, and baggies were set up on OV-104 by technicians. Engineers hope this extra instrumentation will help pinpoint the exact location of the leak. OV-104 is scheduled to be launched for the STS-38 mission, a classified Department of Defense (DOD) flight. View provided by KSC with alternate number KSC-90PC-988.

Resilient filtering for time-varying stochastic coupling networks under the event-triggering scheduling

NASA Astrophysics Data System (ADS)

Wang, Fan; Liang, Jinling; Dobaie, Abdullah M.

2018-07-01

The resilient filtering problem is considered for a class of time-varying networks with stochastic coupling strengths. An event-triggered strategy is adopted to save the network resources by scheduling the signal transmission from the sensors to the filters based on certain prescribed rules. Moreover, the filter parameters to be designed are subject to gain perturbations. The primary aim of the addressed problem is to determine a resilient filter that ensures an acceptable filtering performance for the considered network with event-triggering scheduling. To handle such an issue, an upper bound on the estimation error variance is established for each node according to the stochastic analysis. Subsequently, the resilient filter is designed by locally minimizing the derived upper bound at each iteration. Moreover, rigorous analysis shows the monotonicity of the minimal upper bound regarding the triggering threshold. Finally, a simulation example is presented to show effectiveness of the established filter scheme.

A subjective scheduler for subjective dedicated networks

NASA Astrophysics Data System (ADS)

Suherman; Fakhrizal, Said Reza; Al-Akaidi, Marwan

2017-09-01

Multiple access technique is one of important techniques within medium access layer in TCP/IP protocol stack. Each network technology implements the selected access method. Priority can be implemented in those methods to differentiate services. Some internet networks are dedicated for specific purpose. Education browsing or tutorial video accesses are preferred in a library hotspot, while entertainment and sport contents could be subjects of limitation. Current solution may use IP address filter or access list. This paper proposes subjective properties of users or applications are used for priority determination in multiple access techniques. The NS-2 simulator is employed to evaluate the method. A video surveillance network using WiMAX is chosen as the object. Subjective priority is implemented on WiMAX scheduler based on traffic properties. Three different traffic sources from monitoring video: palace, park, and market are evaluated. The proposed subjective scheduler prioritizes palace monitoring video that results better quality, xx dB than the later monitoring spots.

Space station systems analysis study. Part 3: Documentation. Volume 5: Cost and schedule data

NASA Technical Reports Server (NTRS)

1977-01-01

Cost estimates for the space station systems analysis were recorded. Space construction base costs and characteristics were cited as well as mission hardware costs and characteristics. Also delineated were cost ground rules, the program schedule, and a detail cost estimate and funding distribution.

GPM Launch Day at NASA Goddard (Feb. 27, 2014)

NASA Image and Video Library

2014-02-27

One of the control rooms at NASA’s Goddard Space Flight Center in Greenbelt, Md., prepares for the GPM mission’s Core Observatory on Feb. 27, 2014. Credit: NASA's Goddard Space Flight Center/Debbie McCallum GPM's Core Observatory is poised for launch from the Japan Aerospace Exploration Agency's Tanegashima Space Center, scheduled for the afternoon of Feb. 27, 2014 (EST). GPM is a joint venture between NASA and the Japan Aerospace Exploration Agency. The GPM Core Observatory will link data from a constellation of current and planned satellites to produce next-generation global measurements of rainfall and snowfall from space. The GPM mission is the first coordinated international satellite network to provide near real-time observations of rain and snow every three hours anywhere on the globe. The GPM Core Observatory anchors this network by providing observations on all types of precipitation. The observatory's data acts as the measuring stick by which partner observations can be combined into a unified data set. The data will be used by scientists to study climate change, freshwater resources, floods and droughts, and hurricane formation and tracking. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

GPM Launch Day at NASA Goddard (Feb. 27, 2014)

NASA Image and Video Library

2014-02-27

Children at the visitor center at NASA's Goddard Space Flight Center in Greenbelt, Md., receive a rainfall demonstration as part of activities tied to the launch of the Global Precipitation Measurement mission's Core Observatory on Feb. 27, 2014. Credit: NASA's Goddard Space Flight Center/Debbie McCallum GPM's Core Observatory is poised for launch from the Japan Aerospace Exploration Agency's Tanegashima Space Center, scheduled for the afternoon of Feb. 27, 2014 (EST). GPM is a joint venture between NASA and the Japan Aerospace Exploration Agency. The GPM Core Observatory will link data from a constellation of current and planned satellites to produce next-generation global measurements of rainfall and snowfall from space. The GPM mission is the first coordinated international satellite network to provide near real-time observations of rain and snow every three hours anywhere on the globe. The GPM Core Observatory anchors this network by providing observations on all types of precipitation. The observatory's data acts as the measuring stick by which partner observations can be combined into a unified data set. The data will be used by scientists to study climate change, freshwater resources, floods and droughts, and hurricane formation and tracking. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Active Solution Space and Search on Job-shop Scheduling Problem

NASA Astrophysics Data System (ADS)

Watanabe, Masato; Ida, Kenichi; Gen, Mitsuo

In this paper we propose a new searching method of Genetic Algorithm for Job-shop scheduling problem (JSP). The coding method that represent job number in order to decide a priority to arrange a job to Gannt Chart (called the ordinal representation with a priority) in JSP, an active schedule is created by using left shift. We define an active solution at first. It is solution which can create an active schedule without using left shift, and set of its defined an active solution space. Next, we propose an algorithm named Genetic Algorithm with active solution space search (GA-asol) which can create an active solution while solution is evaluated, in order to search the active solution space effectively. We applied it for some benchmark problems to compare with other method. The experimental results show good performance.

Auditory Training for Adults Who Have Hearing Loss: A Comparison of Spaced versus Massed Practice Schedules

ERIC Educational Resources Information Center

Tye-Murray, Nancy; Spehar, Brent; Barcroft, Joe; Sommers, Mitchell

2017-01-01

Purpose: The spacing effect in human memory research refers to situations in which people learn items better when they study items in spaced intervals rather than massed intervals. This investigation was conducted to compare the efficacy of meaning-oriented auditory training when administered with a spaced versus massed practice schedule. Method:…

Spacing Effects in Vocabulary Learning: Young EFL Learners in Focus

ERIC Educational Resources Information Center

Lotfolahi, Amir Reza; Salehi, Hadi

2017-01-01

This study used a novel method to explore different schedules of spacing in young EFL learners. In doing so, we taught young EFL learners English-Farsi word pairs using different spacing schedules (massed vs. spaced). In the massed condition, learners studied five-word pairs in session one and five-other word pairs one week later. In the spaced…

Study on ecological regulation of coastal plain sluice

NASA Astrophysics Data System (ADS)

Yu, Wengong; Geng, Bing; Yu, Huanfei; Yu, Hongbo

2018-02-01

Coastal plains are densely populated and economically developed, therefore their importance is self-evident. However, there are some problems related with water in coastal plains, such as low flood control capacity and severe water pollution. Due to complicated river network hydrodynamic force, changeable flow direction and uncertain flood concentration and propagation mechanism, it is rather difficult to use sluice scheduling to realize flood control and tackle water pollution. On the base of the measured hydrological data during once-in-a-century Fitow typhoon in 2013 in Yuyao city, by typical analysis, theoretical analysis and process simulation, some key technologies were researched systematically including plain river network sluice ecological scheduling, “one tide” flood control and drainage scheduling and ecological running water scheduling. In the end, single factor health diagnostic evaluation, unit hydrograph of plain water level and evening tide scheduling were put forward.

Constraint-based scheduling

NASA Technical Reports Server (NTRS)

Zweben, Monte

1991-01-01

The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

Constraint-based scheduling

NASA Technical Reports Server (NTRS)

Zweben, Monte

1991-01-01

The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocations for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its applications to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

Constraint-based scheduling

NASA Technical Reports Server (NTRS)

Zweben, Monte

1993-01-01

The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

Considerations for Using an Incremental Scheduler for Human Exploration Task Scheduling

NASA Technical Reports Server (NTRS)

Jaap, John; Phillips, Shaun

2005-01-01

As humankind embarks on longer space missions farther from home, the requirements and environments for scheduling the activities performed on these missions are changing. As we begin to prepare for these missions it is appropriate to evaluate the merits and applicability of the different types of scheduling engines. Scheduling engines temporally arrange tasks onto a timeline so that all constraints and objectives are met and resources are not overbooked. Scheduling engines used to schedule space missions fall into three general categories: batch, mixed-initiative, and incremental. This paper presents an assessment of the engine types, a discussion of the impact of human exploration of the moon and Mars on planning and scheduling, and the applicability of the different types of scheduling engines. This paper will pursue the hypothesis that incremental scheduling engines may have a place in the new environment; they have the potential to reduce cost, to improve the satisfaction of those who execute or benefit from a particular timeline (the customers), and to allow astronauts to plan their own tasks.

Quality of service routing in wireless ad hoc networks

NASA Astrophysics Data System (ADS)

Sane, Sachin J.; Patcha, Animesh; Mishra, Amitabh

2003-08-01

An efficient routing protocol is essential to guarantee application level quality of service running on wireless ad hoc networks. In this paper we propose a novel routing algorithm that computes a path between a source and a destination by considering several important constraints such as path-life, availability of sufficient energy as well as buffer space in each of the nodes on the path between the source and destination. The algorithm chooses the best path from among the multiples paths that it computes between two endpoints. We consider the use of control packets that run at a priority higher than the data packets in determining the multiple paths. The paper also examines the impact of different schedulers such as weighted fair queuing, and weighted random early detection among others in preserving the QoS level guarantees. Our extensive simulation results indicate that the algorithm improves the overall lifetime of a network, reduces the number of dropped packets, and decreases the end-to-end delay for real-time voice application.

Transportation Network Analysis and Decomposition Methods

DOT National Transportation Integrated Search

1978-03-01

The report outlines research in transportation network analysis using decomposition techniques as a basis for problem solutions. Two transportation network problems were considered in detail: a freight network flow problem and a scheduling problem fo...

Stochastic Routing and Scheduling Policies for Energy Harvesting Communication Networks

NASA Astrophysics Data System (ADS)

Calvo-Fullana, Miguel; Anton-Haro, Carles; Matamoros, Javier; Ribeiro, Alejandro

2018-07-01

In this paper, we study the joint routing-scheduling problem in energy harvesting communication networks. Our policies, which are based on stochastic subgradient methods on the dual domain, act as an energy harvesting variant of the stochastic family of backpresure algorithms. Specifically, we propose two policies: (i) the Stochastic Backpressure with Energy Harvesting (SBP-EH), in which a node's routing-scheduling decisions are determined by the difference between the Lagrange multipliers associated to their queue stability constraints and their neighbors'; and (ii) the Stochastic Soft Backpressure with Energy Harvesting (SSBP-EH), an improved algorithm where the routing-scheduling decision is of a probabilistic nature. For both policies, we show that given sustainable data and energy arrival rates, the stability of the data queues over all network nodes is guaranteed. Numerical results corroborate the stability guarantees and illustrate the minimal gap in performance that our policies offer with respect to classical ones which work with an unlimited energy supply.

Space Technology Demonstrations Using Low Cost, Short-Schedule Airborne and Range Facilities at the Dryden Flight Research Center

NASA Technical Reports Server (NTRS)

Carter, John; Kelly, John; Jones, Dan; Lee, James

2013-01-01

There is a national effort to expedite advanced space technologies on new space systems for both government and commercial applications. In order to lower risk, these technologies should be demonstrated in a relevant environment before being installed in new space systems. This presentation introduces several low cost, short schedule space technology demonstrations using airborne and range facilities available at the Dryden Flight Research Center.

Planning as a Precursor to Scheduling for Space Station Payload Operations

NASA Technical Reports Server (NTRS)

Howell, Eric; Maxwell, Theresa

1995-01-01

Contemporary schedulers attempt to solve the problem of best fitting a set of activities into an available timeframe while still satisfying the necessary constraints. This approach produces results which are optimized for the region of time the scheduler is able to process, satisfying the near term goals of the operation. In general the scheduler is not able to reason about the activities which precede or follow the window into which it is inputs to scheduling so that the intermediate placing activities. This creates a problem for operations which are composed of many activities spanning long durations (which exceed the scheduler's reasoning horizon) such as the continuous operations environment for payload operations on the Space Station. Not only must the near term scheduling objectives be met, but somehow the results of near term scheduling must be made to support the attainment of long term goals.

Centralized Routing and Scheduling Using Multi-Channel System Single Transceiver in 802.16d

NASA Astrophysics Data System (ADS)

Al-Hemyari, A.; Noordin, N. K.; Ng, Chee Kyun; Ismail, A.; Khatun, S.

This paper proposes a cross-layer optimized strategy that reduces the effect of interferences from neighboring nodes within a mesh networks. This cross-layer design relies on the routing information in network layer and the scheduling table in medium access control (MAC) layer. A proposed routing algorithm in network layer is exploited to find the best route for all subscriber stations (SS). Also, a proposed centralized scheduling algorithm in MAC layer is exploited to assign a time slot for each possible node transmission. The cross-layer optimized strategy is using multi-channel single transceiver and single channel single transceiver systems for WiMAX mesh networks (WMNs). Each node in WMN has a transceiver that can be tuned to any available channel for eliminating the secondary interference. Among the considered parameters in the performance analysis are interference from the neighboring nodes, hop count to the base station (BS), number of children per node, slot reuse, load balancing, quality of services (QoS), and node identifier (ID). Results show that the proposed algorithms significantly improve the system performance in terms of length of scheduling, channel utilization ratio (CUR), system throughput, and average end to end transmission delay.

Capacity Limit, Link Scheduling and Power Control in Wireless Networks

ERIC Educational Resources Information Center

Zhou, Shan

2013-01-01

The rapid advancement of wireless technology has instigated the broad deployment of wireless networks. Different types of networks have been developed, including wireless sensor networks, mobile ad hoc networks, wireless local area networks, and cellular networks. These networks have different structures and applications, and require different…

Neural Network Prediction of New Aircraft Design Coefficients

NASA Technical Reports Server (NTRS)

Norgaard, Magnus; Jorgensen, Charles C.; Ross, James C.

1997-01-01

This paper discusses a neural network tool for more effective aircraft design evaluations during wind tunnel tests. Using a hybrid neural network optimization method, we have produced fast and reliable predictions of aerodynamical coefficients, found optimal flap settings, and flap schedules. For validation, the tool was tested on a 55% scale model of the USAF/NASA Subsonic High Alpha Research Concept aircraft (SHARC). Four different networks were trained to predict coefficients of lift, drag, moment of inertia, and lift drag ratio (C(sub L), C(sub D), C(sub M), and L/D) from angle of attack and flap settings. The latter network was then used to determine an overall optimal flap setting and for finding optimal flap schedules.

The Planning and Scheduling of HST: Improvements and Enhancements since Launch

NASA Astrophysics Data System (ADS)

Taylor, D. K.; Chance, D. R.; Jordan, I. J. E.; Patterson, A. P.; Stanley, M.; Taylor, D. C.

2001-12-01

The planning and scheduling (P&S) systems used in operating the Hubble Space Telescope (HST) have undergone such substantial and pervasive re-engineering that today they dimly resemble those used when HST was launched. Processes (i.e., software, procedures, networking, etc.) which allow program implementation, the generation of a Long Range Plan (LRP), and the scheduling of science and mission activities have improved drastically in nearly 12 years, resulting in a consistently high observing efficiency, a stable LRP that principal investigators can use, exceptionally clean command loads uplinked to the spacecraft, and the capability of a very fast response time due to onboard anomalies or targets of opportunity. In this presentation we describe many of the systems which comprise the P&S ("front-end") system for HST, how and why they were improved, and what benefits have been realized by either the HST user community or the STScI staff. The systems include the Guide Star System, the Remote Proposal Submission System - 2 (RPS2), Artificial Intelligence (AI) planning tools such as Spike, and the science and mission scheduling software. We also describe how using modern software languages such as Python and better development practices allow STScI staff to do more with HST (e.g., to handle much more science data when ACS is installed) without increasing the cost to HST operations.

Earth Observing System (EOS) Advanced Microwave Sounding Unit-A (AMSU-A) schedule plan

NASA Technical Reports Server (NTRS)

1994-01-01

This report describes Aerojet's methods and procedures used to control and administer contractual schedules for the EOS/AMSU-A program. Included are the following: the master, intermediate, and detail schedules; critical path analysis; and the total program logic network diagrams.

An investigation of the use of temporal decomposition in space mission scheduling

NASA Technical Reports Server (NTRS)

Bullington, Stanley E.; Narayanan, Venkat

1994-01-01

This research involves an examination of techniques for solving scheduling problems in long-duration space missions. The mission timeline is broken up into several time segments, which are then scheduled incrementally. Three methods are presented for identifying the activities that are to be attempted within these segments. The first method is a mathematical model, which is presented primarily to illustrate the structure of the temporal decomposition problem. Since the mathematical model is bound to be computationally prohibitive for realistic problems, two heuristic assignment procedures are also presented. The first heuristic method is based on dispatching rules for activity selection, and the second heuristic assigns performances of a model evenly over timeline segments. These heuristics are tested using a sample Space Station mission and a Spacelab mission. The results are compared with those obtained by scheduling the missions without any problem decomposition. The applicability of this approach to large-scale mission scheduling problems is also discussed.

Automated telescope scheduling

NASA Technical Reports Server (NTRS)

Johnston, Mark D.

1988-01-01

With the ever increasing level of automation of astronomical telescopes the benefits and feasibility of automated planning and scheduling are becoming more apparent. Improved efficiency and increased overall telescope utilization are the most obvious goals. Automated scheduling at some level has been done for several satellite observatories, but the requirements on these systems were much less stringent than on modern ground or satellite observatories. The scheduling problem is particularly acute for Hubble Space Telescope: virtually all observations must be planned in excruciating detail weeks to months in advance. Space Telescope Science Institute has recently made significant progress on the scheduling problem by exploiting state-of-the-art artificial intelligence software technology. What is especially interesting is that this effort has already yielded software that is well suited to scheduling groundbased telescopes, including the problem of optimizing the coordinated scheduling of more than one telescope.

Expert systems tools for Hubble Space Telescope observation scheduling

NASA Technical Reports Server (NTRS)

Miller, Glenn; Rosenthal, Don; Cohen, William; Johnston, Mark

1987-01-01

The utility of expert systems techniques for the Hubble Space Telescope (HST) planning and scheduling is discussed and a plan for development of expert system tools which will augment the existing ground system is described. Additional capabilities provided by these tools will include graphics-oriented plan evaluation, long-range analysis of the observation pool, analysis of optimal scheduling time intervals, constructing sequences of spacecraft activities which minimize operational overhead, and optimization of linkages between observations. Initial prototyping of a scheduler used the Automated Reasoning Tool running on a LISP workstation.

CCSDS Advanced Orbiting Systems Virtual Channel Access Service for QoS MACHETE Model

NASA Technical Reports Server (NTRS)

Jennings, Esther H.; Segui, John S.

2011-01-01

To support various communications requirements imposed by different missions, interplanetary communication protocols need to be designed, validated, and evaluated carefully. Multimission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE), described in "Simulator of Space Communication Networks" (NPO-41373), NASA Tech Briefs, Vol. 29, No. 8 (August 2005), p. 44, combines various tools for simulation and performance analysis of space networks. The MACHETE environment supports orbital analysis, link budget analysis, communications network simulations, and hardware-in-the-loop testing. By building abstract behavioral models of network protocols, one can validate performance after identifying the appropriate metrics of interest. The innovators have extended the MACHETE model library to include a generic link-layer Virtual Channel (VC) model supporting quality-of-service (QoS) controls based on IP streams. The main purpose of this generic Virtual Channel model addition was to interface fine-grain flow-based QoS (quality of service) between the network and MAC layers of the QualNet simulator, a commercial component of MACHETE. This software model adds the capability of mapping IP streams, based on header fields, to virtual channel numbers, allowing extended QoS handling at link layer. This feature further refines the QoS v existing at the network layer. QoS at the network layer (e.g. diffserv) supports few QoS classes, so data from one class will be aggregated together; differentiating between flows internal to a class/priority is not supported. By adding QoS classification capability between network and MAC layers through VC, one maps multiple VCs onto the same physical link. Users then specify different VC weights, and different queuing and scheduling policies at the link layer. This VC model supports system performance analysis of various virtual channel link-layer QoS queuing schemes independent of the network-layer QoS systems.

The Space Shuttle Columbia clears the tower to begin the mission. The liftoff occurred on schedule

NASA Technical Reports Server (NTRS)

1996-01-01

STS-75 LAUNCH VIEW --- The Space Shuttle Columbia clears the tower to begin the mission. The liftoff occurred on schedule at 3:18:00 p.m. (EST), February 22, 1996. Visible at left is the White Room on the orbiter access arm through which the flight crew had entered the orbiter. Onboard Columbia for the scheduled two-week mission were astronauts Andrew M. Allen, commander; Scott J. Horowitz, pilot; Franklin R. Chang-Diaz, payload commander; and astronauts Maurizio Cheli, Jeffrey A. Hoffman and Claude Nicollier, along with payload specialist Umberto Guidioni. Cheli and Nicollier represent the European Space Agency (ESA), while Guidioni represents the Italian Space Agency (ASI).

MPLMs viewed in SSPF

NASA Technical Reports Server (NTRS)

2000-01-01

In the Space Station Processing Facility sits Raffaello, one of two Multi-Purpose Logistics Modules (MPLMs) built by Italy for the International Space Station. Raffaello is scheduled on mission STS-100, the 9th flight to the Space Station in 2001. The other MPLM is Leonardo, scheduled on an earlier mission, STS-102, the 8th flight early in 2001.

MPLMs viewed in SSPF

NASA Technical Reports Server (NTRS)

2000-01-01

In the Space Station Processing Facility sit Leonardo (left) and Raffaello (right), two Multi-Purpose Logistics Modules (MPLMs) built by Italy for the International Space Station. Raffaello is scheduled on mission STS-100, the 9th flight to the Space Station in 2001. The other MPLM is Leonardo, scheduled on an earlier mission, STS-102, the 8th flight early in 2001.

A Flexible System for Simulating Aeronautical Telecommunication Network

NASA Technical Reports Server (NTRS)

Maly, Kurt; Overstreet, C. M.; Andey, R.

1998-01-01

At Old Dominion University, we have built Aeronautical Telecommunication Network (ATN) Simulator with NASA being the fund provider. It provides a means to evaluate the impact of modified router scheduling algorithms on the network efficiency, to perform capacity studies on various network topologies and to monitor and study various aspects of ATN through graphical user interface (GUI). In this paper we describe briefly about the proposed ATN model and our abstraction of this model. Later we describe our simulator architecture highlighting some of the design specifications, scheduling algorithms and user interface. At the end, we have provided the results of performance studies on this simulator.

Training Records And Information Network UNIX Version

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, Michael

1996-12-01

TRAIN-UNIX is used to track training requirements, qualifications, training completion and schedule training, classrooms and instructors. TRAIN-UNIX is a requirements-based system. When the identified training requirements for specific jobs are entered into the system, the employees manager or responsible training person assigns jobs to an employee. TRAIN-UNIX will then assemble an Individual Training Plan (ITP) with all courses required. ITP''s can also be modified to add any special training directed or identified by management, best business practices, procedures, etc. TRAIN-UNIX also schedules and tracks conferences, seminars, and required reading. TRAIN-UNIX is a secure database system on a server accessible viamore » the network. Access to the user functions (scheduling, data entry, ITP modification etc.) within TRAIN-UNIX are granted by function, as needed, by the system administrator. An additional level of security allows those who access TRAIN-UNIX to only add, modify or view information for the organizations to which they belong. TRAIN-UNIX scheduling function allows network access to scheduling of students. As a function of the scheduling process, TRAIN-UNIX checks to insure that the student is a valid employee, not double booked, and the instructor and classroom are not double booked. TRAIN-UNIX will report pending lapse of courses or qualifications. This ability to know the lapse of training along with built in training requesting function allows the training deliverers to forecast training needs.« less

TRAIN-UNIX. Training Records And Information Network UNIX Version

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, M.E.; Crires, J.T.; Johnston, M.

1995-12-01

TRAIN-UNIX is used to track training requirements, qualifications, training completion and schedule training, classrooms and instructors. TRAIN-UNIX is a requirements-based system. When the identified training requirements for specific jobs are entered into the system, the employees manager or responsible training person assigns jobs to an employee. TRAIN-UNIX will then assemble an Individual Training Plan (ITP) with all courses required. ITP`s can also be modified to add any special training directed or identified by management, best business practices, procedures, etc. TRAIN-UNIX also schedules and tracks conferences, seminars, and required reading. TRAIN-UNIX is a secure database system on a server accessible viamore » the network. Access to the user functions (scheduling, data entry, ITP modification etc.) within TRAIN-UNIX are granted by function, as needed, by the system administrator. An additional level of security allows those who access TRAIN-UNIX to only add, modify or view information for the organizations to which they belong. TRAIN-UNIX scheduling function allows network access to scheduling of students. As a function of the scheduling process, TRAIN-UNIX checks to insure that the student is a valid employee, not double booked, and the instructor and classroom are not double booked. TRAIN-UNIX will report pending lapse of courses or qualifications. This ability to know the lapse of training along with built in training requesting function allows the training deliverers to forecast training needs.« less

32 GHz Celestial Reference Frame Survey for Dec < -45 deg.

NASA Astrophysics Data System (ADS)

Horiuchi, Shinji; Phillips, Chris; Stevens, Jamie; Jacobs, Christopher; Sotuela, Ioana; Garcia miro, Cristina

2013-04-01

(We resubmit this proposal to extend from the previous semester. The 24 hour blocks for ATCA and Mopra were granted in May 2012 but canceled because fringe test before the scheduled experiment failed although fringes were detected between Mopra and Tidbinbilla. As it turned out ATCA had an issue with frequency standard, which has now been resolved.) We propose to conduct a LBA survey of compact radio sources at 32 GHz near the south pole region. This is the first attempt to fill the gap in the existing 32 GHz catalogue establish by NASA Deep Space Network toward completing the full sky celestial reference frame at 32 GHz. The catalogue will be used for future spacecraft navigation by NASA and other space agencies as well as for radio astronomical observations with southern radio telescope arrays such as ATCA and LBA.

Contact Graph Routing

NASA Technical Reports Server (NTRS)

Burleigh, Scott C.

2011-01-01

Contact Graph Routing (CGR) is a dynamic routing system that computes routes through a time-varying topology of scheduled communication contacts in a network based on the DTN (Delay-Tolerant Networking) architecture. It is designed to enable dynamic selection of data transmission routes in a space network based on DTN. This dynamic responsiveness in route computation should be significantly more effective and less expensive than static routing, increasing total data return while at the same time reducing mission operations cost and risk. The basic strategy of CGR is to take advantage of the fact that, since flight mission communication operations are planned in detail, the communication routes between any pair of bundle agents in a population of nodes that have all been informed of one another's plans can be inferred from those plans rather than discovered via dialogue (which is impractical over long one-way-light-time space links). Messages that convey this planning information are used to construct contact graphs (time-varying models of network connectivity) from which CGR automatically computes efficient routes for bundles. Automatic route selection increases the flexibility and resilience of the space network, simplifying cross-support and reducing mission management costs. Note that there are no routing tables in Contact Graph Routing. The best route for a bundle destined for a given node may routinely be different from the best route for a different bundle destined for the same node, depending on bundle priority, bundle expiration time, and changes in the current lengths of transmission queues for neighboring nodes; routes must be computed individually for each bundle, from the Bundle Protocol agent's current network connectivity model for the bundle s destination node (the contact graph). Clearly this places a premium on optimizing the implementation of the route computation algorithm. The scalability of CGR to very large networks remains a research topic. The information carried by CGR contact plan messages is useful not only for dynamic route computation, but also for the implementation of rate control, congestion forecasting, transmission episode initiation and termination, timeout interval computation, and retransmission timer suspension and resumption.

Toward an Autonomous Telescope Network: the TBT Scheduler

NASA Astrophysics Data System (ADS)

Racero, E.; Ibarra, A.; Ocaña, F.; de Lis, S. B.; Ponz, J. D.; Castillo, M.; Sánchez-Portal, M.

2015-09-01

Within the ESA SSA program, it is foreseen to deploy several robotic telescopes to provide surveillance and tracking services for hazardous objects. The TBT project will procure a validation platform for an autonomous optical observing system in a realistic scenario, consisting of two telescopes located in Spain and Australia, to collect representative test data for precursor SSA services. In this context, the planning and scheduling of the night consists of two software modules, the TBT Scheduler, that will allow the manual and autonomous planning of the night, and the control of the real-time response of the system, done by the RTS2 internal scheduler. The TBT Scheduler allocates tasks for both telescopes without human intervention. Every night it takes all the inputs needed and prepares the schedule following some predefined rules. The main purpose of the scheduler is the distribution of the time for follow-up of recently discovered targets and surveys. The TBT Scheduler considers the overall performance of the system, and combine follow-up with a priori survey strategies for both kind of objects. The strategy is defined according to the expected combined performance for both systems the upcoming night (weather, sky brightness, object accessibility and priority). Therefore, TBT Scheduler defines the global approach for the network and relies on the RTS2 internal scheduler for the final detailed distribution of tasks at each sensor.

Critical Path Method Networks and Their Use in Claims Analysis.

DTIC Science & Technology

1984-01-01

produced will only be as good as the time invested and the knowledge of the scheduler. A schedule which is based on faulty logic or which contains... fundementals of putting a schedule together but also *how the construction process functions so that the delays can be accurately inserted. When

A Genetic Algorithm Tool (splicer) for Complex Scheduling Problems and the Space Station Freedom Resupply Problem

NASA Technical Reports Server (NTRS)

Wang, Lui; Valenzuela-Rendon, Manuel

1993-01-01

The Space Station Freedom will require the supply of items in a regular fashion. A schedule for the delivery of these items is not easy to design due to the large span of time involved and the possibility of cancellations and changes in shuttle flights. This paper presents the basic concepts of a genetic algorithm model, and also presents the results of an effort to apply genetic algorithms to the design of propellant resupply schedules. As part of this effort, a simple simulator and an encoding by which a genetic algorithm can find near optimal schedules have been developed. Additionally, this paper proposes ways in which robust schedules, i.e., schedules that can tolerate small changes, can be found using genetic algorithms.

A survey of planning and scheduling research at the NASA Ames Research Center

NASA Technical Reports Server (NTRS)

Zweben, Monte

1989-01-01

NASA Ames Research Center has a diverse program in planning and scheduling. Some research projects as well as some applications are highlighted. Topics addressed include machine learning techniques, action representations and constraint-based scheduling systems. The applications discussed are planetary rovers, Hubble Space Telescope scheduling, and Pioneer Venus orbit scheduling.

14 CFR 399.81 - Unrealistic or deceptive scheduling.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Unrealistic or deceptive scheduling. 399.81... Unrealistic or deceptive scheduling. (a) It is the policy of the Board to consider unrealistic scheduling of... to the advertising of scheduled performance, it is the policy of the Board to regard as an unfair or...

Scheduling lessons learned from the Autonomous Power System

NASA Technical Reports Server (NTRS)

Ringer, Mark J.

1992-01-01

The Autonomous Power System (APS) project at NASA LeRC is designed to demonstrate the applications of integrated intelligent diagnosis, control, and scheduling techniques to space power distribution systems. The project consists of three elements: the Autonomous Power Expert System (APEX) for Fault Diagnosis, Isolation, and Recovery (FDIR); the Autonomous Intelligent Power Scheduler (AIPS) to efficiently assign activities start times and resources; and power hardware (Brassboard) to emulate a space-based power system. The AIPS scheduler was tested within the APS system. This scheduler is able to efficiently assign available power to the requesting activities and share this information with other software agents within the APS system in order to implement the generated schedule. The AIPS scheduler is also able to cooperatively recover from fault situations by rescheduling the affected loads on the Brassboard in conjunction with the APEX FDIR system. AIPS served as a learning tool and an initial scheduling testbed for the integration of FDIR and automated scheduling systems. Many lessons were learned from the AIPS scheduler and are now being integrated into a new scheduler called SCRAP (Scheduler for Continuous Resource Allocation and Planning). This paper will service three purposes: an overview of the AIPS implementation, lessons learned from the AIPS scheduler, and a brief section on how these lessons are being applied to the new SCRAP scheduler.

A hybrid job-shop scheduling system

NASA Technical Reports Server (NTRS)

Hellingrath, Bernd; Robbach, Peter; Bayat-Sarmadi, Fahid; Marx, Andreas

1992-01-01

The intention of the scheduling system developed at the Fraunhofer-Institute for Material Flow and Logistics is the support of a scheduler working in a job-shop. Due to the existing requirements for a job-shop scheduling system the usage of flexible knowledge representation and processing techniques is necessary. Within this system the attempt was made to combine the advantages of symbolic AI-techniques with those of neural networks.

Pitch Guidance Optimization for the Orion Abort Flight Tests

NASA Technical Reports Server (NTRS)

Stillwater, Ryan Allanque

2010-01-01

The National Aeronautics and Space Administration created the Constellation program to develop the next generation of manned space vehicles and launch vehicles. The Orion abort system is initiated in the event of an unsafe condition during launch. The system has a controller gains schedule that can be tuned to reduce the attitude errors between the simulated Orion abort trajectories and the guidance trajectory. A program was created that uses the method of steepest descent to tune the pitch gains schedule by an automated procedure. The gains schedule optimization was applied to three potential abort scenarios; each scenario tested using the optimized gains schedule resulted in reduced attitude errors when compared to the Orion production gains schedule.

Unsupervised, Robust Estimation-based Clustering for Multispectral Images

NASA Technical Reports Server (NTRS)

Netanyahu, Nathan S.

1997-01-01

To prepare for the challenge of handling the archiving and querying of terabyte-sized scientific spatial databases, the NASA Goddard Space Flight Center's Applied Information Sciences Branch (AISB, Code 935) developed a number of characterization algorithms that rely on supervised clustering techniques. The research reported upon here has been aimed at continuing the evolution of some of these supervised techniques, namely the neural network and decision tree-based classifiers, plus extending the approach to incorporating unsupervised clustering algorithms, such as those based on robust estimation (RE) techniques. The algorithms developed under this task should be suited for use by the Intelligent Information Fusion System (IIFS) metadata extraction modules, and as such these algorithms must be fast, robust, and anytime in nature. Finally, so that the planner/schedule module of the IlFS can oversee the use and execution of these algorithms, all information required by the planner/scheduler must be provided to the IIFS development team to ensure the timely integration of these algorithms into the overall system.

Centralized mission planning and scheduling system for the Landsat Data Continuity Mission

USGS Publications Warehouse

Kavelaars, Alicia; Barnoy, Assaf M.; Gregory, Shawna; Garcia, Gonzalo; Talon, Cesar; Greer, Gregory; Williams, Jason; Dulski, Vicki

2014-01-01

Satellites in Low Earth Orbit provide missions with closer range for studying aspects such as geography and topography, but often require efficient utilization of space and ground assets. Optimizing schedules for these satellites amounts to a complex planning puzzle since it requires operators to face issues such as discontinuous ground contacts, limited onboard memory storage, constrained downlink margin, and shared ground antenna resources. To solve this issue for the Landsat Data Continuity Mission (LDCM, Landsat 8), all the scheduling exchanges for science data request, ground/space station contact, and spacecraft maintenance and control will be coordinated through a centralized Mission Planning and Scheduling (MPS) engine, based upon GMV’s scheduling system flexplan9 . The synchronization between all operational functions must be strictly maintained to ensure efficient mission utilization of ground and spacecraft activities while working within the bounds of the space and ground resources, such as Solid State Recorder (SSR) and available antennas. This paper outlines the functionalities that the centralized planning and scheduling system has in its operational control and management of the Landsat 8 spacecraft.

Fair Energy Scheduling for Vehicle-to-Grid Networks Using Adaptive Dynamic Programming.

PubMed

Xie, Shengli; Zhong, Weifeng; Xie, Kan; Yu, Rong; Zhang, Yan

2016-08-01

Research on the smart grid is being given enormous supports worldwide due to its great significance in solving environmental and energy crises. Electric vehicles (EVs), which are powered by clean energy, are adopted increasingly year by year. It is predictable that the huge charge load caused by high EV penetration will have a considerable impact on the reliability of the smart grid. Therefore, fair energy scheduling for EV charge and discharge is proposed in this paper. By using the vehicle-to-grid technology, the scheduler controls the electricity loads of EVs considering fairness in the residential distribution network. We propose contribution-based fairness, in which EVs with high contributions have high priorities to obtain charge energy. The contribution value is defined by both the charge/discharge energy and the timing of the action. EVs can achieve higher contribution values when discharging during the load peak hours. However, charging during this time will decrease the contribution values seriously. We formulate the fair energy scheduling problem as an infinite-horizon Markov decision process. The methodology of adaptive dynamic programming is employed to maximize the long-term fairness by processing online network training. The numerical results illustrate that the proposed EV energy scheduling is able to mitigate and flatten the peak load in the distribution network. Furthermore, contribution-based fairness achieves a fast recovery of EV batteries that have deeply discharged and guarantee fairness in the full charge time of all EVs.

Maximally Expressive Modeling

NASA Technical Reports Server (NTRS)

Jaap, John; Davis, Elizabeth; Richardson, Lea

2004-01-01

Planning and scheduling systems organize tasks into a timeline or schedule. Tasks are logically grouped into containers called models. Models are a collection of related tasks, along with their dependencies and requirements, that when met will produce the desired result. One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed; the information sought is at the cutting edge of scientific endeavor; and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a maximally expressive modeling schema.

Space Shuttle processing - A case study in artificial intelligence

NASA Technical Reports Server (NTRS)

Mollikarimi, Cindy; Gargan, Robert; Zweben, Monte

1991-01-01

A scheduling system incorporating AI is described and applied to the automated processing of the Space Shuttle. The unique problem of addressing the temporal, resource, and orbiter-configuration requirements of shuttle processing is described with comparisons to traditional project management for manufacturing processes. The present scheduling system is developed to handle the late inputs and complex programs that characterize shuttle processing by incorporating fixed preemptive scheduling, constraint-based simulated annealing, and the characteristics of an 'anytime' algorithm. The Space-Shuttle processing environment is modeled with 500 activities broken down into 4000 subtasks and with 1600 temporal constraints, 8000 resource constraints, and 3900 state requirements. The algorithm is shown to scale to very large problems and maintain anytime characteristics suggesting that an automated scheduling process is achievable and potentially cost-effective.

Automated Scheduling of Personnel to Staff Operations for the Mars Science Laboratory

NASA Technical Reports Server (NTRS)

Knight, Russell; Mishkin, Andrew; Allbaugh, Alicia

2014-01-01

Leveraging previous work on scheduling personnel for space mission operations, we have adapted ASPEN (Activity Scheduling and Planning Environment) [1] to the domain of scheduling personnel for operations of the Mars Science Laboratory. Automated scheduling of personnel is not new. We compare our representations to a sampling of employee scheduling systems available with respect to desired features. We described the constraints required by MSL personnel schedulers and how each is handled by the scheduling algorithm.

Traffic shaping and scheduling for OBS-based IP/WDM backbones

NASA Astrophysics Data System (ADS)

Elhaddad, Mahmoud S.; Melhem, Rami G.; Znati, Taieb; Basak, Debashis

2003-10-01

We introduce Proactive Reservation-based Switching (PRS) -- a switching architecture for IP/WDM networks based on Labeled Optical Burst Switching. PRS achieves packet delay and loss performance comparable to that of packet-switched networks, without requiring large buffering capacity, or burst scheduling across a large number of wavelengths at the core routers. PRS combines proactive channel reservation with periodic shaping of ingress-egress traffic aggregates to hide the offset latency and approximate the utilization/buffering characteristics of discrete-time queues with periodic arrival streams. A channel scheduling algorithm imposes constraints on burst departure times to ensure efficient utilization of wavelength channels and to maintain the distance between consecutive bursts through the network. Results obtained from simulation using TCP traffic over carefully designed topologies indicate that PRS consistently achieves channel utilization above 90% with modest buffering requirements.

An AI approach for scheduling space-station payloads at Kennedy Space Center

NASA Technical Reports Server (NTRS)

Castillo, D.; Ihrie, D.; Mcdaniel, M.; Tilley, R.

1987-01-01

The Payload Processing for Space-Station Operations (PHITS) is a prototype modeling tool capable of addressing many Space Station related concerns. The system's object oriented design approach coupled with a powerful user interface provide the user with capabilities to easily define and model many applications. PHITS differs from many artificial intelligence based systems in that it couples scheduling and goal-directed simulation to ensure that on-orbit requirement dates are satisfied.

Energy-saving scheme based on downstream packet scheduling in ethernet passive optical networks

NASA Astrophysics Data System (ADS)

Zhang, Lincong; Liu, Yejun; Guo, Lei; Gong, Xiaoxue

2013-03-01

With increasing network sizes, the energy consumption of Passive Optical Networks (PONs) has grown significantly. Therefore, it is important to design effective energy-saving schemes in PONs. Generally, energy-saving schemes have focused on sleeping the low-loaded Optical Network Units (ONUs), which tends to bring large packet delays. Further, the traditional ONU sleep modes are not capable of sleeping the transmitter and receiver independently, though they are not required to transmit or receive packets. Clearly, this approach contributes to wasted energy. Thus, in this paper, we propose an Energy-Saving scheme that is based on downstream Packet Scheduling (ESPS) in Ethernet PON (EPON). First, we design both an algorithm and a rule for downstream packet scheduling at the inter- and intra-ONU levels, respectively, to reduce the downstream packet delay. After that, we propose a hybrid sleep mode that contains not only ONU deep sleep mode but also independent sleep modes for the transmitter and the receiver. This ensures that the energy consumed by the ONUs is minimal. To realize the hybrid sleep mode, a modified GATE control message is designed that involves 10 time points for sleep processes. In ESPS, the 10 time points are calculated according to the allocated bandwidths in both the upstream and the downstream. The simulation results show that ESPS outperforms traditional Upstream Centric Scheduling (UCS) scheme in terms of energy consumption and the average delay for both real-time and non-real-time packets downstream. The simulation results also show that the average energy consumption of each ONU in larger-sized networks is less than that in smaller-sized networks; hence, our ESPS is better suited for larger-sized networks.

Mission scheduling

NASA Technical Reports Server (NTRS)

Gaspin, Christine

1989-01-01

How a neural network can work, compared to a hybrid system based on an operations research and artificial intelligence approach, is investigated through a mission scheduling problem. The characteristic features of each system are discussed.

KSC-05PD-0126

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. On Launch Pad 17-B, Cape Canaveral Air Force Station, Fla., shadows paint the Boeing Delta II rocket carrying the Deep Impact spacecraft as the mobile service tower at left is rolled back before launch.Scheduled for liftoff at 1:47 p.m. EST today, Deep Impact will head for space and a rendezvous with Comet Tempel 1 when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile (impactor) to crash onto the surface July 4, 2005, Deep Impacts flyby spacecraft will reveal the secrets of the comets interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0125

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. On Launch Pad 17-B, Cape Canaveral Air Force Station, Fla., the Boeing Delta II rocket carrying the Deep Impact spacecraft looms into the night sky as the mobile service tower at right is rolled back before launch. Scheduled for liftoff at 1:47 p.m. EST today, Deep Impact will head for space and a rendezvous with Comet Tempel 1 when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile (impactor) to crash onto the surface July 4, 2005, Deep Impacts flyby spacecraft will reveal the secrets of the comets interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0127

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. On Launch Pad 17-B, Cape Canaveral Air Force Station, Fla., the Boeing Delta II carrying the Deep Impact spacecraft rocket shines under spotlights in the early dawn hours as it waits for launch. Scheduled for liftoff at 1:47 p.m. EST today, Deep Impact will head for space and a rendezvous with Comet Tempel 1 when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile (impactor) to crash onto the surface July 4, 2005, Deep Impacts flyby spacecraft will reveal the secrets of the comets interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

KSC-05PD-0129

NASA Technical Reports Server (NTRS)

2005-01-01

KENNEDY SPACE CENTER, FLA. The sun rises behind Launch Pad 17-B, Cape Canaveral Air Force Station, Fla., where the Boeing Delta II rocket carrying the Deep Impact spacecraft waits for launch. Gray clouds above the horizon belie the favorable weather forecast for the afternoon launch. Scheduled for liftoff at 1:47 p.m. EST today, Deep Impact will head for space and a rendezvous with Comet Tempel 1 when the comet is 83 million miles from Earth. After releasing a 3- by 3-foot projectile (impactor) to crash onto the surface July 4, 2005, Deep Impacts flyby spacecraft will reveal the secrets of the comets interior by collecting pictures and data of how the crater forms, measuring the craters depth and diameter as well as the composition of the interior of the crater and any material thrown out, and determining the changes in natural outgassing produced by the impact. It will send the data back to Earth through the antennas of the Deep Space Network. Deep Impact is a NASA Discovery mission.

Maximally Expressive Modeling of Operations Tasks

NASA Technical Reports Server (NTRS)

Jaap, John; Richardson, Lea; Davis, Elizabeth

2002-01-01

Planning and scheduling systems organize "tasks" into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as "a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled." One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed, the information sought is at the cutting edge of scientific endeavor, and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a "maximally expressive" modeling schema.

In-Space Crew-Collaborative Task Scheduling

NASA Technical Reports Server (NTRS)

Jaap, John; Meyer, Patrick; Davis, Elizabeth; Richardson, Lea

2007-01-01

For all past and current human space missions, the final scheduling of tasks to be done in space has been devoid of crew control, flexibility, and insight. Ground controllers, with minimal input from the crew, schedule the tasks and uplink the timeline to the crew or uplink the command sequences to the hardware. Prior to the International Space Station (ISS), the crew could make requests about tomorrow s timeline, they could omit a task, or they could request that something in the timeline be delayed. This lack of control over one's own schedule has had negative consequences. There is anecdotal consensus among astronauts that control over their own schedules will mitigate the stresses of long duration missions. On ISS, a modicum of crew control is provided by the job jar. Ground controllers prepare a task list (a.k.a. "job jar") of non-conflicting tasks from which jobs can be chosen by the in space crew. Because there is little free time and few interesting non-conflicting activities, the task-list approach provides little relief from the tedium of being micro-managed by the timeline. Scheduling for space missions is a complex and laborious undertaking which usually requires a large cadre of trained specialists and suites of complex software tools. It is a giant leap from today s ground prepared timeline (with a job jar) to full crew control of the timeline. However, technological advances, currently in-work or proposed, make it reasonable to consider scheduling a collaborative effort by the ground-based teams and the in-space crew. Collaboration would allow the crew to make minor adjustments, add tasks according to their preferences, understand the reasons for the placement of tasks on the timeline, and provide them a sense of control. In foreseeable but extraordinary situations, such as a quick response to anomalies and extended or unexpected loss of signal, the crew should have the autonomous ability to make appropriate modifications to the timeline, extend the timeline, or even start over with a new timeline. The Vision for Space Exploration (VSE), currently being pursued by the National Aeronautics and Space Administration (NASA), will send humans to Mars in a few decades. Stresses on the human mind will be exacerbated by the longer durations and greater distances, and it will be imperative to implement stress-reducing innovations such as giving the crew control of their daily activities.

Sao Paulo Lightning Mapping Array (SP-LMA): Network Assessment and Analyses for Intercomparison Studies and GOES-R Proxy Activities

NASA Technical Reports Server (NTRS)

Bailey, J. C.; Blakeslee, R. J.; Carey, L. D.; Goodman, S. J.; Rudlosky, S. D.; Albrecht, R.; Morales, C. A.; Anselmo, E. M.; Neves, J. R.; Buechler, D. E.

2014-01-01

A 12 station Lightning Mapping Array (LMA) network was deployed during October 2011 in the vicinity of Sao Paulo, Brazil (SP-LMA) to contribute total lightning measurements to an international field campaign [CHUVA - Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)]. The SP-LMA was operational from November 2011 through March 2012 during the Vale do Paraiba campaign. Sensor spacing was on the order of 15-30 km, with a network diameter on the order of 40-50km. The SP-LMA provides good 3-D lightning mapping out to 150 km from the network center, with 2-D coverage considerably farther. In addition to supporting CHUVA science/mission objectives, the SP-LMA is supporting the generation of unique proxy data for the Geostationary Lightning Mapper (GLM) and Advanced Baseline Imager (ABI), on NOAA's Geostationary Operational Environmental Satellite-R (GOES-R: scheduled for a 2015 launch). These proxy data will be used to develop and validate operational algorithms so that they will be ready to use on "day1" following the GOES-R launch. As the CHUVA Vale do Paraiba campaign opportunity was formulated, a broad community-based interest developed for a comprehensive Lightning Location System (LLS) intercomparison and assessment study, leading to the participation and/or deployment of eight other ground-based networks and the space-based Lightning Imaging Sensor (LIS). The SP-LMA data is being intercompared with lightning observations from other deployed lightning networks to advance our understanding of the capabilities/contributions of each of these networks toward GLM proxy and validation activities. This paper addresses the network assessment including noise reduction criteria, detection efficiency estimates, and statistical and climatological (both temporal and spatially) analyses for intercomparison studies and GOES-R proxy activities.

An optimal general type-2 fuzzy controller for Urban Traffic Network.

PubMed

Khooban, Mohammad Hassan; Vafamand, Navid; Liaghat, Alireza; Dragicevic, Tomislav

2017-01-01

Urban traffic network model is illustrated by state-charts and object-diagram. However, they have limitations to show the behavioral perspective of the Traffic Information flow. Consequently, a state space model is used to calculate the half-value waiting time of vehicles. In this study, a combination of the general type-2 fuzzy logic sets and the Modified Backtracking Search Algorithm (MBSA) techniques are used in order to control the traffic signal scheduling and phase succession so as to guarantee a smooth flow of traffic with the least wait times and average queue length. The parameters of input and output membership functions are optimized simultaneously by the novel heuristic algorithm MBSA. A comparison is made between the achieved results with those of optimal and conventional type-1 fuzzy logic controllers. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Energy-efficient process-stacking multiplexing access for 60-GHz mm-wave wireless personal area networks.

PubMed

Estevez, Claudio; Kailas, Aravind

2012-01-01

Millimeter-wave technology shows high potential for future wireless personal area networks, reaching over 1 Gbps transmissions using simple modulation techniques. Current specifications consider dividing the spectrum into effortlessly separable spectrum ranges. These low requirements open a research area in time and space multiplexing techniques for millimeter-waves. In this work a process-stacking multiplexing access algorithm is designed for single channel operation. The concept is intuitive, but its implementation is not trivial. The key to stacking single channel events is to operate while simultaneously obtaining and handling a-posteriori time-frame information of scheduled events. This information is used to shift a global time pointer that the wireless access point manages and uses to synchronize all serviced nodes. The performance of the proposed multiplexing access technique is lower bounded by the performance of legacy TDMA and can significantly improve the effective throughput. Work is validated by simulation results.

Medical image diagnoses by artificial neural networks with image correlation, wavelet transform, simulated annealing

NASA Astrophysics Data System (ADS)

Szu, Harold H.

1993-09-01

Classical artificial neural networks (ANN) and neurocomputing are reviewed for implementing a real time medical image diagnosis. An algorithm known as the self-reference matched filter that emulates the spatio-temporal integration ability of the human visual system might be utilized for multi-frame processing of medical imaging data. A Cauchy machine, implementing a fast simulated annealing schedule, can determine the degree of abnormality by the degree of orthogonality between the patient imagery and the class of features of healthy persons. An automatic inspection process based on multiple modality image sequences is simulated by incorporating the following new developments: (1) 1-D space-filling Peano curves to preserve the 2-D neighborhood pixels' relationship; (2) fast simulated Cauchy annealing for the global optimization of self-feature extraction; and (3) a mini-max energy function for the intra-inter cluster-segregation respectively useful for top-down ANN designs.

LIBRA: An inexpensive geodetic network densification system

NASA Technical Reports Server (NTRS)

Fliegel, H. F.; Gantsweg, M.; Callahan, P. S.

1975-01-01

A description is given of the Libra (Locations Interposed by Ranging Aircraft) system, by which geodesy and earth strain measurements can be performed rapidly and inexpensively to several hundred auxiliary points with respect to a few fundamental control points established by any other technique, such as radio interferometry or satellite ranging. This low-cost means of extending the accuracy of space age geodesy to local surveys provides speed and spatial resolution useful, for example, for earthquake hazards estimation. Libra may be combined with an existing system, Aries (Astronomical Radio Interferometric Earth Surveying) to provide a balanced system adequate to meet the geophysical needs, and applicable to conventional surveying. The basic hardware design was outlined and specifications were defined. Then need for network densification was described. The following activities required to implement the proposed Libra system are also described: hardware development, data reduction, tropospheric calibrations, schedule of development and estimated costs.

From Fob to Noc: A Pathway to a Cyber Career for Combat Veterans

DTIC Science & Technology

2014-06-01

Assurance Certifications GS general schedule HSAC Homeland Security Advisory Council IDS intrusion detection system IP internet protocol IPS...NIPRNET non-secure internet protocol router network NIST National Institute for Standards and Technology NOC network operations center NSA National...twice a day on an irregular schedule or during contact with the enemy to keep any observing enemy wary of the force protection 13 condition at any

An Analysis of Shuttle Crew Scheduling Violations

NASA Technical Reports Server (NTRS)

Bristol, Douglas

2012-01-01

From the early years of the Space Shuttle program, National Aeronautics and Space Administration (NASA) Shuttle crews have had a timeline of activities to guide them through their time on-orbit. Planners used scheduling constraints to build timelines that ensured the health and safety of the crews. If a constraint could not be met it resulted in a violation. Other agencies of the federal government also have scheduling constraints to ensure the safety of personnel and the public. This project examined the history of Space Shuttle scheduling constraints, constraints from Federal agencies and branches of the military and how these constraints may be used as a guide for future NASA and private spacecraft. This was conducted by reviewing rules and violations with regard to human aerospace scheduling constraints, environmental, political, social and technological factors, operating environment and relevant human factors. This study includes a statistical analysis of Shuttle Extra Vehicular Activity (EVA) related violations to determine if these were a significant producer of constraint violations. It was hypothesized that the number of SCSC violations caused by EVA activities were a significant contributor to the total number of violations for Shuttle/ISS missions. Data was taken from NASA data archives at the Johnson Space Center from Space Shuttle/ISS missions prior to the STS-107 accident. The results of the analysis rejected the null hypothesis and found that EVA violations were a significant contributor to the total number of violations. This analysis could help NASA and commercial space companies understand the main source of constraint violations and allow them to create constraint rules that ensure the safe operation of future human private and exploration missions. Additional studies could be performed to evaluate other variables that could have influenced the scheduling violations that were analyzed.

TDRS-L Media Day

NASA Image and Video Library

2014-01-03

TITUSVILLE, Fla. – Members of the news media are given an opportunity for an up-close look at the Tracking and Data Relay Satellite, or TDRS-L, spacecraft undergoing preflight processing inside the Astrotech payload processing facility in Titusville. TDRS-L is being prepared for encapsulation inside its payload fairing prior to being transported to Launch Complex 41 at Cape Canaveral Air Force Station. Journalists visited Astrotech as part of TDRS-L Media Day to conduct interviews and photograph the satellite that will be a part of the second of three next-generation spacecraft designed to ensure vital operational continuity for the NASA Space Network. It is scheduled to launch from Cape Canaveral's Space Launch Complex 41 atop an Atlas V rocket in January 2014. The current Tracking and Data Relay Satellite system consists of eight in-orbit satellites distributed to provide near continuous information relay contact with orbiting spacecraft ranging from the International Space Station and Hubble Space Telescope to the array of scientific observatories. For more information, visit: http://www.nasa.gov/mission_pages/tdrs/home/index.html

Development of a Dynamic Time Sharing Scheduled Environment Final Report CRADA No. TC-824-94E

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jette, M.; Caliga, D.

Massively parallel computers, such as the Cray T3D, have historically supported resource sharing solely with space sharing. In that method, multiple problems are solved by executing them on distinct processors. This project developed a dynamic time- and space-sharing scheduler to achieve greater interactivity and throughput than could be achieved with space-sharing alone. CRI and LLNL worked together on the design, testing, and review aspects of this project. There were separate software deliverables. CFU implemented a general purpose scheduling system as per the design specifications. LLNL ported the local gang scheduler software to the LLNL Cray T3D. In this approach, processorsmore » are allocated simultaneously to aU components of a parallel program (in a “gang”). Program execution is preempted as needed to provide for interactivity. Programs are also reIocated to different processors as needed to efficiently pack the computer’s torus of processors. In phase one, CRI developed an interface specification after discussions with LLNL for systemlevel software supporting a time- and space-sharing environment on the LLNL T3D. The two parties also discussed interface specifications for external control tools (such as scheduling policy tools, system administration tools) and applications programs. CRI assumed responsibility for the writing and implementation of all the necessary system software in this phase. In phase two, CRI implemented job-rolling on the Cray T3D, a mechanism for preempting a program, saving its state to disk, and later restoring its state to memory for continued execution. LLNL ported its gang scheduler to the LLNL T3D utilizing the CRI interface implemented in phases one and two. During phase three, the functionality and effectiveness of the LLNL gang scheduler was assessed to provide input to CRI time- and space-sharing, efforts. CRI will utilize this information in the development of general schedulers suitable for other sites and future architectures.« less

Integrated Dynamic Process Planning and Scheduling in Flexible Manufacturing Systems via Autonomous Agents

NASA Astrophysics Data System (ADS)

Nejad, Hossein Tehrani Nik; Sugimura, Nobuhiro; Iwamura, Koji; Tanimizu, Yoshitaka

Process planning and scheduling are important manufacturing planning activities which deal with resource utilization and time span of manufacturing operations. The process plans and the schedules generated in the planning phase shall be modified in the execution phase due to the disturbances in the manufacturing systems. This paper deals with a multi-agent architecture of an integrated and dynamic system for process planning and scheduling for multi jobs. A negotiation protocol is discussed, in this paper, to generate the process plans and the schedules of the manufacturing resources and the individual jobs, dynamically and incrementally, based on the alternative manufacturing processes. The alternative manufacturing processes are presented by the process plan networks discussed in the previous paper, and the suitable process plans and schedules are searched and generated to cope with both the dynamic status and the disturbances of the manufacturing systems. We initiatively combine the heuristic search algorithms of the process plan networks with the negotiation protocols, in order to generate suitable process plans and schedules in the dynamic manufacturing environment. A simulation software has been developed to carry out case studies, aimed at verifying the performance of the proposed multi-agent architecture.

Energy latency tradeoffs for medium access and sleep scheduling in wireless sensor networks

NASA Astrophysics Data System (ADS)

Gang, Lu

Wireless sensor networks are expected to be used in a wide range of applications from environment monitoring to event detection. The key challenge is to provide energy efficient communication; however, latency remains an important concern for many applications that require fast response. The central thesis of this work is that energy efficient medium access and sleep scheduling mechanisms can be designed without necessarily sacrificing application-specific latency performance. We validate this thesis through results from four case studies that cover various aspects of medium access and sleep scheduling design in wireless sensor networks. Our first effort, DMAC, is to design an adaptive low latency and energy efficient MAC for data gathering to reduce the sleep latency. We propose staggered schedule, duty cycle adaptation, data prediction and the use of more-to-send packets to enable seamless packet forwarding under varying traffic load and channel contentions. Simulation and experimental results show significant energy savings and latency reduction while ensuring high data reliability. The second research effort, DESS, investigates the problem of designing sleep schedules in arbitrary network communication topologies to minimize the worst case end-to-end latency (referred to as delay diameter). We develop a novel graph-theoretical formulation, derive and analyze optimal solutions for the tree and ring topologies and heuristics for arbitrary topologies. The third study addresses the problem of minimum latency joint scheduling and routing (MLSR). By constructing a novel delay graph, the optimal joint scheduling and routing can be solved by M node-disjoint paths algorithm under multiple channel model. We further extended the algorithm to handle dynamic traffic changes and topology changes. A heuristic solution is proposed for MLSR under single channel interference. In the fourth study, EEJSPC, we first formulate a fundamental optimization problem that provides tunable energy-latency-throughput tradeoffs with joint scheduling and power control and present both exponential and polynomial complexity solutions. Then we investigate the problem of minimizing total transmission energy while satisfying transmission requests within a latency bound, and present an iterative approach which converges rapidly to the optimal parameter settings.

Wave scheduling - Decentralized scheduling of task forces in multicomputers

NASA Technical Reports Server (NTRS)

Van Tilborg, A. M.; Wittie, L. D.

1984-01-01

Decentralized operating systems that control large multicomputers need techniques to schedule competing parallel programs called task forces. Wave scheduling is a probabilistic technique that uses a hierarchical distributed virtual machine to schedule task forces by recursively subdividing and issuing wavefront-like commands to processing elements capable of executing individual tasks. Wave scheduling is highly resistant to processing element failures because it uses many distributed schedulers that dynamically assign scheduling responsibilities among themselves. The scheduling technique is trivially extensible as more processing elements join the host multicomputer. A simple model of scheduling cost is used by every scheduler node to distribute scheduling activity and minimize wasted processing capacity by using perceived workload to vary decentralized scheduling rules. At low to moderate levels of network activity, wave scheduling is only slightly less efficient than a central scheduler in its ability to direct processing elements to accomplish useful work.

Development of a decentralized multi-axis synchronous control approach for real-time networks.

PubMed

Xu, Xiong; Gu, Guo-Ying; Xiong, Zhenhua; Sheng, Xinjun; Zhu, Xiangyang

2017-05-01

The message scheduling and the network-induced delays of real-time networks, together with the different inertias and disturbances in different axes, make the synchronous control of the real-time network-based systems quite challenging. To address this challenge, a decentralized multi-axis synchronous control approach is developed in this paper. Due to the limitations of message scheduling and network bandwidth, error of the position synchronization is firstly defined in the proposed control approach as a subset of preceding-axis pairs. Then, a motion message estimator is designed to reduce the effect of network delays. It is proven that position and synchronization errors asymptotically converge to zero in the proposed controller with the delay compensation. Finally, simulation and experimental results show that the developed control approach can achieve the good position synchronization performance for the multi-axis motion over the real-time network. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Wireless Sensor Network Metrics for Real-Time Systems

DTIC Science & Technology

2009-05-20

to compute the probability of end-to-end packet delivery as a function of latency, the expected radio energy consumption on the nodes from relaying... schedules for WSNs. Particularly, we focus on the impact scheduling has on path diversity, using short repeating schedules and Greedy Maximal Matching...a greedy algorithm for constructing a mesh routing topology. Finally, we study the implications of using distributed scheduling schemes to generate

Steps Toward Optimal Competitive Scheduling

NASA Technical Reports Server (NTRS)

Frank, Jeremy; Crawford, James; Khatib, Lina; Brafman, Ronen

2006-01-01

This paper is concerned with the problem of allocating a unit capacity resource to multiple users within a pre-defined time period. The resource is indivisible, so that at most one user can use it at each time instance. However, different users may use it at different times. The users have independent, se@sh preferences for when and for how long they are allocated this resource. Thus, they value different resource access durations differently, and they value different time slots differently. We seek an optimal allocation schedule for this resource. This problem arises in many institutional settings where, e.g., different departments, agencies, or personal, compete for a single resource. We are particularly motivated by the problem of scheduling NASA's Deep Space Satellite Network (DSN) among different users within NASA. Access to DSN is needed for transmitting data from various space missions to Earth. Each mission has different needs for DSN time, depending on satellite and planetary orbits. Typically, the DSN is over-subscribed, in that not all missions will be allocated as much time as they want. This leads to various inefficiencies - missions spend much time and resource lobbying for their time, often exaggerating their needs. NASA, on the other hand, would like to make optimal use of this resource, ensuring that the good for NASA is maximized. This raises the thorny problem of how to measure the utility to NASA of each allocation. In the typical case, it is difficult for the central agency, NASA in our case, to assess the value of each interval to each user - this is really only known to the users who understand their needs. Thus, our problem is more precisely formulated as follows: find an allocation schedule for the resource that maximizes the sum of users preferences, when the preference values are private information of the users. We bypass this problem by making the assumptions that one can assign money to customers. This assumption is reasonable; a committee is usually in charge of deciding the priority of each mission competing for access to the DSN within a time period while scheduling. Instead, we can assume that the committee assigns a budget to each mission.This paper is concerned with the problem of allocating a unit capacity resource to multiple users within a pre-defined time period. The resource is indivisible, so that at most one user can use it at each time instance. However, different users may use it at different times. The users have independent, se@sh preferences for when and for how long they are allocated this resource. Thus, they value different resource access durations differently, and they value different time slots differently. We seek an optimal allocation schedule for this resource. This problem arises in many institutional settings where, e.g., different departments, agencies, or personal, compete for a single resource. We are particularly motivated by the problem of scheduling NASA's Deep Space Satellite Network (DSN) among different users within NASA. Access to DSN is needed for transmitting data from various space missions to Earth. Each mission has different needs for DSN time, depending on satellite and planetary orbits. Typically, the DSN is over-subscribed, in that not all missions will be allocated as much time as they want. This leads to various inefficiencies - missions spend much time and resource lobbying for their time, often exaggerating their needs. NASA, on the other hand, would like to make optimal use of this resource, ensuring that the good for NASA is maximized. This raises the thorny problem of how to measure the utility to NASA of each allocation. In the typical case, it is difficult for the central agency, NASA in our case, to assess the value of each interval to each user - this is really only known to the users who understand their needs. Thus, our problem is more precisely formulated as follows: find an allocation schedule for the resource that maximizes the sum ofsers preferences, when the preference values are private information of the users. We bypass this problem by making the assumptions that one can assign money to customers. This assumption is reasonable; a committee is usually in charge of deciding the priority of each mission competing for access to the DSN within a time period while scheduling. Instead, we can assume that the committee assigns a budget to each mission.

User’s guide to SNAP for ArcGIS® :ArcGIS interface for scheduling and network analysis program

Treesearch

Woodam Chung; Dennis Dykstra; Fred Bower; Stephen O’Brien; Richard Abt; John. and Sessions

2012-01-01

This document introduces a computer software named SNAP for ArcGIS® , which has been developed to streamline scheduling and transportation planning for timber harvest areas. Using modern optimization techniques, it can be used to spatially schedule timber harvest with consideration of harvesting costs, multiple products, alternative...

Space Geodetic Technique Co-location in Space: Simulation Results for the GRASP Mission

NASA Astrophysics Data System (ADS)

Kuzmicz-Cieslak, M.; Pavlis, E. C.

2011-12-01

The Global Geodetic Observing System-GGOS, places very stringent requirements in the accuracy and stability of future realizations of the International Terrestrial Reference Frame (ITRF): an origin definition at 1 mm or better at epoch and a temporal stability on the order of 0.1 mm/y, with similar numbers for the scale (0.1 ppb) and orientation components. These goals were derived from the requirements of Earth science problems that are currently the international community's highest priority. None of the geodetic positioning techniques can achieve this goal alone. This is due in part to the non-observability of certain attributes from a single technique. Another limitation is imposed from the extent and uniformity of the tracking network and the schedule of observational availability and number of suitable targets. The final limitation derives from the difficulty to "tie" the reference points of each technique at the same site, to an accuracy that will support the GGOS goals. The future GGOS network will address decisively the ground segment and to certain extent the space segment requirements. The JPL-proposed multi-technique mission GRASP (Geodetic Reference Antenna in Space) attempts to resolve the accurate tie between techniques, using their co-location in space, onboard a well-designed spacecraft equipped with GNSS receivers, a SLR retroreflector array, a VLBI beacon and a DORIS system. Using the anticipated system performance for all four techniques at the time the GGOS network is completed (ca 2020), we generated a number of simulated data sets for the development of a TRF. Our simulation studies examine the degree to which GRASP can improve the inter-technique "tie" issue compared to the classical approach, and the likely modus operandi for such a mission. The success of the examined scenarios is judged by the quality of the origin and scale definition of the resulting TRF.

Web Design for Space Operations: An Overview of the Challenges and New Technologies Used in Developing and Operating Web-Based Applications in Real-Time Operational Support Onboard the International Space Station, in Astronaut Mission Planning and Mission Control Operations

NASA Technical Reports Server (NTRS)

Khan, Ahmed

2010-01-01

The International Space Station (ISS) Operations Planning Team, Mission Control Centre and Mission Automation Support Network (MAS) have all evolved over the years to use commercial web-based technologies to create a configurable electronic infrastructure to manage the complex network of real-time planning, crew scheduling, resource and activity management as well as onboard document and procedure management required to co-ordinate ISS assembly, daily operations and mission support. While these Web technologies are classified as non-critical in nature, their use is part of an essential backbone of daily operations on the ISS and allows the crew to operate the ISS as a functioning science laboratory. The rapid evolution of the internet from 1998 (when ISS assembly began) to today, along with the nature of continuous manned operations in space, have presented a unique challenge in terms of software engineering and system development. In addition, the use of a wide array of competing internet technologies (including commercial technologies such as .NET and JAVA ) and the special requirements of having to support this network, both nationally among various control centres for International Partners (IPs), as well as onboard the station itself, have created special challenges for the MCC Web Tools Development Team, software engineers and flight controllers, who implement and maintain this system. This paper presents an overview of some of these operational challenges, and the evolving nature of the solutions and the future use of COTS based rich internet technologies in manned space flight operations. In particular this paper will focus on the use of Microsoft.s .NET API to develop Web-Based Operational tools, the use of XML based service oriented architectures (SOA) that needed to be customized to support Mission operations, the maintenance of a Microsoft IIS web server onboard the ISS, The OpsLan, functional-oriented Web Design with AJAX

Multi-layer service function chaining scheduling based on auxiliary graph in IP over optical network

NASA Astrophysics Data System (ADS)

Li, Yixuan; Li, Hui; Liu, Yuze; Ji, Yuefeng

2017-10-01

Software Defined Optical Network (SDON) can be considered as extension of Software Defined Network (SDN) in optical networks. SDON offers a unified control plane and makes optical network an intelligent transport network with dynamic flexibility and service adaptability. For this reason, a comprehensive optical transmission service, able to achieve service differentiation all the way down to the optical transport layer, can be provided to service function chaining (SFC). IP over optical network, as a promising networking architecture to interconnect data centers, is the most widely used scenarios of SFC. In this paper, we offer a flexible and dynamic resource allocation method for diverse SFC service requests in the IP over optical network. To do so, we firstly propose the concept of optical service function (OSF) and a multi-layer SFC model. OSF represents the comprehensive optical transmission service (e.g., multicast, low latency, quality of service, etc.), which can be achieved in multi-layer SFC model. OSF can also be considered as a special SF. Secondly, we design a resource allocation algorithm, which we call OSF-oriented optical service scheduling algorithm. It is able to address multi-layer SFC optical service scheduling and provide comprehensive optical transmission service, while meeting multiple optical transmission requirements (e.g., bandwidth, latency, availability). Moreover, the algorithm exploits the concept of Auxiliary Graph. Finally, we compare our algorithm with the Baseline algorithm in simulation. And simulation results show that our algorithm achieves superior performance than Baseline algorithm in low traffic load condition.

14 CFR 206.2 - Exemption from schedule filing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Exemption from schedule filing. 206.2 Section 206.2 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS CERTIFICATES OF PUBLIC CONVENIENCE AND NECESSITY: SPECIAL AUTHORIZATIONS AND...

SPIKE: Application for ASTRO-D mission planning

NASA Technical Reports Server (NTRS)

Isobe, T.; Johnston, M.; Morgan, E.; Clark, G.

1992-01-01

SPIKE is a mission planning software system developed by a team of programmers at the STScI for use with the Hubble Space Telescope (HST). SPIKE has been developed for the purpose of automating observatory scheduling to increase the effective utilization and ultimately, scientific return from orbiting telescopes. High-level scheduling strategies using both rule-based and neural network approaches have been incorporated. Graphical displays of activities, constraints, and schedules are an important feature of the system. Although SPIKE was originally developed for the HST, it can be used for other astronomy missions including ground-based observatories. One of the missions that has decided to use SPIKE is ASTRO-D, a Japanese X-ray satellite for which the U.S. is providing a part of the scientific payload. Scheduled to fly in Feb. 1993, its four telescopes will focus X-rays over a wide energy range onto CCD's and imaging gas proportional counters. ASTRO-D will be the first X-ray imaging mission operating over the 0.5-12 keV band with high energy resolution. This combination of capabilities will enable a varied and exciting program of astronomical research to be carried out. ASTRO-D is expected to observe 5 to 20 objects per day and a total of several thousands per year. This requires the implementation of an efficient planning and scheduling system which SPIKE can provide. Although the version of SPIKE that will be used for ASTRO-D mission is almost identical to that used for the HST, there are a few differences. For example, ASTRO-D will use two ground stations for data downlinks, instead of the TDRSS system for data transmission. As a consequence ASTRO-D is constrained by limited on-board data storage capacity to schedule high data-rate observations during periods of frequent high bit rate observations accordingly. We will demonstrate the ASTRO-D version of SPIKE to show what SPIKE can provide and how efficiently it creates an observational schedule.

Incremental Scheduling Engines for Human Exploration of the Cosmos

NASA Technical Reports Server (NTRS)

Jaap, John; Phillips, Shaun

2005-01-01

As humankind embarks on longer space missions farther from home, the requirements and environments for scheduling the activities performed on these missions are changing. As we begin to prepare for these missions it is appropriate to evaluate the merits and applicability of the different types of scheduling engines. Scheduling engines temporally arrange tasks onto a timeline so that all constraints and objectives are met and resources are not overbooked. Scheduling engines used to schedule space missions fall into three general categories: batch, mixed-initiative, and incremental. This paper presents an assessment of the engine types, a discussion of the impact of human exploration of the moon and Mars on planning and scheduling, and the applicability of the different types of scheduling engines. This paper will pursue the hypothesis that incremental scheduling engines may have a place in the new environment; they have the potential to reduce cost, to improve the satisfaction of those who execute or benefit from a particular timeline (the customers), and to allow astronauts to plan their own tasks and those of their companion robots.

Incremental Scheduling Engines: Cost Savings through Automation

NASA Technical Reports Server (NTRS)

Jaap, John; Phillips, Shaun

2005-01-01

As humankind embarks on longer space missions farther from home, the requirements and environments for scheduling the activities performed on these missions are changing. As we begin to prepare for these missions it is appropriate to evaluate the merits and applicability of the different types of scheduling engines. Scheduling engines temporally arrange tasks onto a timeline so that all constraints and ob.jectives are met and resources are not over-booked. Scheduling engines used to schedule space missions fall into three general categories: batch, mixed-initiative, and incremental. This paper, presents an assessment of the engine types, a discussion of the impact of human exploration of the moon and Mars on planning and scheduling, and the applicability of the different types of scheduling engines. This paper will pursue the hypothesis that incremental scheduling engines may have a place in the new environment; they have the potential to reduce cost, to improve the satisfaction of those who execute or benefit from a particular timeline (the customers), and to allow astronauts to plan their own tasks and those of their companion robots.

Improvements to Integrated Tradespace Analysis of Communications Architectures (ITACA) Network Loading Analysis Tool

NASA Technical Reports Server (NTRS)

Lee, Nathaniel; Welch, Bryan W.

2018-01-01

NASA's SCENIC project aims to simplify and reduce the cost of space mission planning by replicating the analysis capabilities of commercially licensed software which are integrated with relevant analysis parameters specific to SCaN assets and SCaN supported user missions. SCENIC differs from current tools that perform similar analyses in that it 1) does not require any licensing fees, 2) will provide an all-in-one package for various analysis capabilities that normally requires add-ons or multiple tools to complete. As part of SCENIC's capabilities, the ITACA network loading analysis tool will be responsible for assessing the loading on a given network architecture and generating a network service schedule. ITACA will allow users to evaluate the quality of service of a given network architecture and determine whether or not the architecture will satisfy the mission's requirements. ITACA is currently under development, and the following improvements were made during the fall of 2017: optimization of runtime, augmentation of network asset pre-service configuration time, augmentation of Brent's method of root finding, augmentation of network asset FOV restrictions, augmentation of mission lifetimes, and the integration of a SCaN link budget calculation tool. The improvements resulted in (a) 25% reduction in runtime, (b) more accurate contact window predictions when compared to STK(Registered Trademark) contact window predictions, and (c) increased fidelity through the use of specific SCaN asset parameters.

TTEthernet for Integrated Spacecraft Networks

NASA Technical Reports Server (NTRS)

Loveless, Andrew

2015-01-01

Aerospace projects have traditionally employed federated avionics architectures, in which each computer system is designed to perform one specific function (e.g. navigation). There are obvious downsides to this approach, including excessive weight (from so much computing hardware), and inefficient processor utilization (since modern processors are capable of performing multiple tasks). There has therefore been a push for integrated modular avionics (IMA), in which common computing platforms can be leveraged for different purposes. This consolidation of multiple vehicle functions to shared computing platforms can significantly reduce spacecraft cost, weight, and design complexity. However, the application of IMA principles introduces significant challenges, as the data network must accommodate traffic of mixed criticality and performance levels - potentially all related to the same shared computer hardware. Because individual network technologies are rarely so competent, the development of truly integrated network architectures often proves unreasonable. Several different types of networks are utilized - each suited to support a specific vehicle function. Critical functions are typically driven by precise timing loops, requiring networks with strict guarantees regarding message latency (i.e. determinism) and fault-tolerance. Alternatively, non-critical systems generally employ data networks prioritizing flexibility and high performance over reliable operation. Switched Ethernet has seen widespread success filling this role in terrestrial applications. Its high speed, flexibility, and the availability of inexpensive commercial off-the-shelf (COTS) components make it desirable for inclusion in spacecraft platforms. Basic Ethernet configurations have been incorporated into several preexisting aerospace projects, including both the Space Shuttle and International Space Station (ISS). However, classical switched Ethernet cannot provide the high level of network determinism required by real-time spacecraft applications. Even with modern advancements, the uncoordinated (i.e. event-driven) nature of Ethernet communication unavoidably leads to message contention within network switches. The arbitration process used to resolve such conflicts introduces variation in the time it takes for messages to be forwarded. TTEthernet1 introduces decentralized clock synchronization to switched Ethernet, enabling message transmission according to a time-triggered (TT) paradigm. A network planning tool is used to allocate each device a finite amount of time in which it may transmit a frame. Each time slot is repeated sequentially to form a periodic communication schedule that is then loaded onto each TTEthernet device (e.g. switches and end systems). Each network participant references the synchronized time in order to dispatch messages at predetermined instances. This schedule guarantees that no contention exists between time-triggered Ethernet frames in the network switches, therefore eliminating the need for arbitration (and the timing variation it causes). Besides time-triggered messaging, TTEthernet networks may provide two additional traffic classes to support communication of different criticality levels. In the rate-constrained (RC) traffic class, the frame payload size and rate of transmission along each communication channel are limited to predetermined maximums. The network switches can therefore be configured to accommodate the known worst-case traffic pattern, and buffer overflows can be eliminated. The best-effort (BE) traffic class behaves akin to classical Ethernet. No guarantees are provided regarding transmission latency or successful message delivery. TTEthernet coordinates transmission of all three traffic classes over the same physical connections, therefore accommodating the full spectrum of traffic criticality levels required in IMA architectures. Common computing platforms (e.g. LRUs) can share networking resources in such a way that failures in non-critical systems (using BE or RC communication modes) cannot impact flight-critical functions (using TT communication). Furthermore, TTEthernet hardware (e.g. switches, cabling) can be shared by both TTEthernet and classical Ethernet traffic.

Data Processing Center of Radioastron Project: 3 years of operation.

NASA Astrophysics Data System (ADS)

Shatskaya, Marina

ASC DATA PROCESSING CENTER (DPC) of Radioastron Project is a fail-safe complex centralized system of interconnected software/ hardware components along with organizational procedures. Tasks facing of the scientific data processing center are organization of service information exchange, collection of scientific data, storage of all of scientific data, data science oriented processing. DPC takes part in the informational exchange with two tracking stations in Pushchino (Russia) and Green Bank (USA), about 30 ground telescopes, ballistic center, tracking headquarters and session scheduling center. Enormous flows of information go to Astro Space Center. For the inquiring of enormous data volumes we develop specialized network infrastructure, Internet channels and storage. The computer complex has been designed at the Astro Space Center (ASC) of Lebedev Physical Institute and includes: - 800 TB on-line storage, - 2000 TB hard drive archive, - backup system on magnetic tapes (2000 TB); - 24 TB redundant storage at Pushchino Radio Astronomy Observatory; - Web and FTP servers, - DPC management and data transmission networks. The structure and functions of ASC Data Processing Center are fully adequate to the data processing requirements of the Radioastron Mission and has been successfully confirmed during Fringe Search, Early Science Program and first year of Key Science Program.

Aspects of job scheduling

NASA Technical Reports Server (NTRS)

Phillips, K.

1976-01-01

A mathematical model for job scheduling in a specified context is presented. The model uses both linear programming and combinatorial methods. While designed with a view toward optimization of scheduling of facility and plant operations at the Deep Space Communications Complex, the context is sufficiently general to be widely applicable. The general scheduling problem including options for scheduling objectives is discussed and fundamental parameters identified. Mathematical algorithms for partitioning problems germane to scheduling are presented.

MPLMs viewed in SSPF

NASA Technical Reports Server (NTRS)

2000-01-01

The Multi-Purpose Logistics Module (MPLM) Leonardo, seen here, is one of two in the Space Station Processing Facility. The other is named Raffaello. Both MPLMs are components built by Italy for the International Space Station. Leonardo is scheduled on mission STS-102, the 8th flight to the Space Station early in 2001. Raffaello is scheduled on mission STS-100, the 9th flight, later in 2001.

MPLMs viewed in SSPF

NASA Technical Reports Server (NTRS)

2000-01-01

The Multi-Purpose Logistics Module (MPLM) Raffaello, seen here, is one of two in the Space Station Processing Facility. The other is named Leonardo. Both MPLMs are components built by Italy for the International Space Station. Raffaello is scheduled on mission STS-100, the 9th flight to the Space Station in 2001. Leonardo is scheduled on an earlier mission, STS-102, the 8th flight early in 2001.

Astronaut Russell Schweickart inside simulator for EVA training

NASA Image and Video Library

1968-12-11

S68-55391 (11 Dec. 1968) --- Astronaut Russell L. Schweickart, lunar module pilot of the Apollo 9 (Spacecraft 104/Lunar Module 3/Saturn 504) space mission, is seen inside Chamber "A," Space Environment Simulation Laboratory, Building 32, participating in dry run activity in preparation for extravehicular activity which is scheduled in Chamber "A." The purpose of the scheduled training is to familiarize the crewmen with the operation of EVA equipment in a simulated space environment. In addition, metabolic and workload profiles will be simulated on each crewman. Astronauts Schweickart and Alan L. Bean, backup lunar module pilot, are scheduled to receive thermal-vacuum training simulating Earth-orbital EVA.

ECS: efficient communication scheduling for underwater sensor networks.

PubMed

Hong, Lu; Hong, Feng; Guo, Zhongwen; Li, Zhengbao

2011-01-01

TDMA protocols have attracted a lot of attention for underwater acoustic sensor networks (UWSNs), because of the unique characteristics of acoustic signal propagation such as great energy consumption in transmission, long propagation delay and long communication range. Previous TDMA protocols all allocated transmission time to nodes based on discrete time slots. This paper proposes an efficient continuous time scheduling TDMA protocol (ECS) for UWSNs, including the continuous time based and sender oriented conflict analysis model, the transmission moment allocation algorithm and the distributed topology maintenance algorithm. Simulation results confirm that ECS improves network throughput by 20% on average, compared to existing MAC protocols.

A new scheduling algorithm to provide proportional QoS in optical burst switching networks

NASA Astrophysics Data System (ADS)

Tan, Wei; Luo, Yunhan; Wang, Sheng; Xu, Du; Pan, Yonghong; Li, Lemin

2005-02-01

A new scheduling algorithm, which aims to provide proportional and controllable QoS in terms of burst loss probability for OBS (optical burst switching) networks, is proposed on the basis of a summary of current QoS schemes in OBS. With simulations, performance analyses and comparisons are studied in detail. The results show that, in the proposed scheme, burst loss probabilities are proportional to the given factors and the control of QoS performance can be achieved with better performance. This scheme will be beneficial to the OBS network management and the tariff policy making.

Healthcare4VideoStorm: Making Smart Decisions Based on Storm Metrics.

PubMed

Zhang, Weishan; Duan, Pengcheng; Chen, Xiufeng; Lu, Qinghua

2016-04-23

Storm-based stream processing is widely used for real-time large-scale distributed processing. Knowing the run-time status and ensuring performance is critical to providing expected dependability for some applications, e.g., continuous video processing for security surveillance. The existing scheduling strategies' granularity is too coarse to have good performance, and mainly considers network resources without computing resources while scheduling. In this paper, we propose Healthcare4Storm, a framework that finds Storm insights based on Storm metrics to gain knowledge from the health status of an application, finally ending up with smart scheduling decisions. It takes into account both network and computing resources and conducts scheduling at a fine-grained level using tuples instead of topologies. The comprehensive evaluation shows that the proposed framework has good performance and can improve the dependability of the Storm-based applications.

Video conferencing made easy

NASA Technical Reports Server (NTRS)

Larsen, D. Gail; Schwieder, Paul R.

1993-01-01

Network video conferencing is advancing rapidly throughout the nation, and the Idaho National Engineering Laboratory (INEL), a Department of Energy (DOE) facility, is at the forefront of the development. Engineers at INEL/EG&G designed and installed a very unique DOE videoconferencing system, offering many outstanding features, that include true multipoint conferencing, user-friendly design and operation with no full-time operators required, and the potential for cost effective expansion of the system. One area where INEL/EG&G engineers made a significant contribution to video conferencing was in the development of effective, user-friendly, end station driven scheduling software. A PC at each user site is used to schedule conferences via a windows package. This software interface provides information to the users concerning conference availability, scheduling, initiation, and termination. The menus are 'mouse' controlled. Once a conference is scheduled, a workstation at the hubs monitors the network to initiate all scheduled conferences. No active operator participation is required once a user schedules a conference through the local PC; the workstation automatically initiates and terminates the conference as scheduled. As each conference is scheduled, hard copy notification is also printed at each participating site. Video conferencing is the wave of the future. The use of these user-friendly systems will save millions in lost productivity and travel cost throughout the nation. The ease of operation and conference scheduling will play a key role on the extent industry uses this new technology. The INEL/EG&G has developed a prototype scheduling system for both commercial and federal government use.

Efficiently Scheduling Multi-core Guest Virtual Machines on Multi-core Hosts in Network Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoginath, Srikanth B; Perumalla, Kalyan S

2011-01-01

Virtual machine (VM)-based simulation is a method used by network simulators to incorporate realistic application behaviors by executing actual VMs as high-fidelity surrogates for simulated end-hosts. A critical requirement in such a method is the simulation time-ordered scheduling and execution of the VMs. Prior approaches such as time dilation are less efficient due to the high degree of multiplexing possible when multiple multi-core VMs are simulated on multi-core host systems. We present a new simulation time-ordered scheduler to efficiently schedule multi-core VMs on multi-core real hosts, with a virtual clock realized on each virtual core. The distinguishing features of ourmore » approach are: (1) customizable granularity of the VM scheduling time unit on the simulation time axis, (2) ability to take arbitrary leaps in virtual time by VMs to maximize the utilization of host (real) cores when guest virtual cores idle, and (3) empirically determinable optimality in the tradeoff between total execution (real) time and time-ordering accuracy levels. Experiments show that it is possible to get nearly perfect time-ordered execution, with a slight cost in total run time, relative to optimized non-simulation VM schedulers. Interestingly, with our time-ordered scheduler, it is also possible to reduce the time-ordering error from over 50% of non-simulation scheduler to less than 1% realized by our scheduler, with almost the same run time efficiency as that of the highly efficient non-simulation VM schedulers.« less

Video conferencing made easy

NASA Astrophysics Data System (ADS)

Larsen, D. Gail; Schwieder, Paul R.

1993-02-01

Network video conferencing is advancing rapidly throughout the nation, and the Idaho National Engineering Laboratory (INEL), a Department of Energy (DOE) facility, is at the forefront of the development. Engineers at INEL/EG&G designed and installed a very unique DOE videoconferencing system, offering many outstanding features, that include true multipoint conferencing, user-friendly design and operation with no full-time operators required, and the potential for cost effective expansion of the system. One area where INEL/EG&G engineers made a significant contribution to video conferencing was in the development of effective, user-friendly, end station driven scheduling software. A PC at each user site is used to schedule conferences via a windows package. This software interface provides information to the users concerning conference availability, scheduling, initiation, and termination. The menus are 'mouse' controlled. Once a conference is scheduled, a workstation at the hubs monitors the network to initiate all scheduled conferences. No active operator participation is required once a user schedules a conference through the local PC; the workstation automatically initiates and terminates the conference as scheduled. As each conference is scheduled, hard copy notification is also printed at each participating site. Video conferencing is the wave of the future. The use of these user-friendly systems will save millions in lost productivity and travel cost throughout the nation. The ease of operation and conference scheduling will play a key role on the extent industry uses this new technology. The INEL/EG&G has developed a prototype scheduling system for both commercial and federal government use.

Video conferencing made easy

NASA Astrophysics Data System (ADS)

Larsen, D. G.; Schwieder, P. R.

Network video conferencing is advancing rapidly throughout the nation, and the Idaho National Engineering Laboratory (INEL), a Department of Energy (DOE) facility, is at the forefront of the development. Engineers at INEL/EG&G designed and installed a very unique DOE video conferencing system, offering many outstanding features, that include true multipoint conferencing, user-friendly design and operation with no full-time operators required, and the potential for cost effective expansion of the system. One area where INEL/EG&G engineers made a significant contribution to video conferencing was in the development of effective, user-friendly, end station driven scheduling software. A PC at each user site is used to schedule conferences via a windows package. This software interface provides information to the users concerning conference availability, scheduling, initiation, and termination. The menus are 'mouse' controlled. Once a conference is scheduled, a workstation at the hub monitors the network to initiate all scheduled conferences. No active operator participation is required once a user schedules a conference through the local PC; the workstation automatically initiates and terminates the conference as scheduled. As each conference is scheduled, hard copy notification is also printed at each participating site. Video conferencing is the wave of the future. The use of these user-friendly systems will save millions in lost productivity and travel costs throughout the nation. The ease of operation and conference scheduling will play a key role on the extent industry uses this new technology. The INEL/EG&G has developed a prototype scheduling system for both commercial and federal government use.

Autonomous Hybrid Priority Queueing for Scheduling Residential Energy Demands

NASA Astrophysics Data System (ADS)

Kalimullah, I. Q.; Shamroukh, M.; Sahar, N.; Shetty, S.

2017-05-01

The advent of smart grid technologies has opened up opportunities to manage the energy consumption of the users within a residential smart grid system. Demand response management is particularly being employed to reduce the overall load on an electricity network which could in turn reduce outages and electricity costs. The objective of this paper is to develop an intelligible scheduler to optimize the energy available to a micro grid through hybrid queueing algorithm centered around the consumers’ energy demands. This is achieved by shifting certain schedulable load appliances to light load hours. Various factors such as the type of demand, grid load, consumers’ energy usage patterns and preferences are considered while formulating the logical constraints required for the algorithm. The algorithm thus obtained is then implemented in MATLAB workspace to simulate its execution by an Energy Consumption Scheduler (ECS) found within smart meters, which automatically finds the optimal energy consumption schedule tailor made to fit each consumer within the micro grid network.

Proportional fair scheduling algorithm based on traffic in satellite communication system

NASA Astrophysics Data System (ADS)

Pan, Cheng-Sheng; Sui, Shi-Long; Liu, Chun-ling; Shi, Yu-Xin

2018-02-01

In the satellite communication network system, in order to solve the problem of low system capacity and user fairness in multi-user access to satellite communication network in the downlink, combined with the characteristics of user data service, an algorithm study on throughput capacity and user fairness scheduling is proposed - Proportional Fairness Algorithm Based on Traffic(B-PF). The algorithm is improved on the basis of the proportional fairness algorithm in the wireless communication system, taking into account the user channel condition and caching traffic information. The user outgoing traffic is considered as the adjustment factor of the scheduling priority and presents the concept of traffic satisfaction. Firstly,the algorithm calculates the priority of the user according to the scheduling algorithm and dispatches the users with the highest priority. Secondly, when a scheduled user is the business satisfied user, the system dispatches the next priority user. The simulation results show that compared with the PF algorithm, B-PF can improve the system throughput, the business satisfaction and fairness.

Evaluation of scheduling techniques for payload activity planning

NASA Technical Reports Server (NTRS)

Bullington, Stanley F.

1991-01-01

Two tasks related to payload activity planning and scheduling were performed. The first task involved making a comparison of space mission activity scheduling problems with production scheduling problems. The second task consisted of a statistical analysis of the output of runs of the Experiment Scheduling Program (ESP). Details of the work which was performed on these two tasks are presented.

A survey of planning and scheduling research at the NASA Ames Research Center

NASA Technical Reports Server (NTRS)

Zweben, Monte

1988-01-01

NASA Ames Research Center has a diverse program in planning and scheduling. This paper highlights some of our research projects as well as some of our applications. Topics addressed include machine learning techniques, action representations and constraint-based scheduling systems. The applications discussed are planetary rovers, Hubble Space Telescope scheduling, and Pioneer Venus orbit scheduling.

Scheduler Design Criteria: Requirements and Considerations

NASA Technical Reports Server (NTRS)

Lee, Hanbong

2016-01-01

This presentation covers fundamental requirements and considerations for developing schedulers in airport operations. We first introduce performance and functional requirements for airport surface schedulers. Among various optimization problems in airport operations, we focus on airport surface scheduling problem, including runway and taxiway operations. We then describe a basic methodology for airport surface scheduling such as node-link network model and scheduling algorithms previously developed. Next, we explain how to design a mathematical formulation in more details, which consists of objectives, decision variables, and constraints. Lastly, we review other considerations, including optimization tools, computational performance, and performance metrics for evaluation.

Managing Capital Investments and Resources for Large, Complex Satellite Development Efforts

NASA Technical Reports Server (NTRS)

Ryan, Richard M.

2017-01-01

Once the schedule was baselined and the primary, secondary, and tertiary critical paths (at least) were established: Identified what entity control which portion of the schedule reserve Dollarized the time associated with the schedule reserve and segregated it off from other budget reserves authorization to spend only came when authorization to utilize the time was given Created a process to manage the control of these resources This process was above and beyond the typical schedule controls used to monitor and maintain the day-to-day schedules Webb telescope will be the premier space observatory for astronomers worldwide,extending the tantalizing discoveries of the Hubble Space telescope• An international collaboration among NASA, the European Space Agency, and theCanadian Space Agency• The largest telescope ever placed in space, Webb will be 100 times more powerful thanHubble• It is so big it has to fold origami-style to fit in the rocket and will unfold like a transformeronce in space• The 5-layer sunshield protects the telescope from the Sun, Earth, and Moon’s infraredradiation. It’s like having sun protection of SPF 1 million• Unprecedented infrared sensitivity will peer back in time over 13.5 billion years to see thefirst galaxies born after the Big Bang• Hubble orbits 350 miles above the Earth; Webb will orbit the sun 1 million miles fromEarth• Launch from French Guiana in 2018

System and Method for Network Bandwidth, Buffers and Timing Management Using Hybrid Scheduling of Traffic with Different Priorities and Guarantees

NASA Technical Reports Server (NTRS)

Bonk, Ted (Inventor); Hall, Brendan (Inventor); Smithgall, William Todd (Inventor); Varadarajan, Srivatsan (Inventor); DeLay, Benjamin F. (Inventor)

2017-01-01

Systems and methods for network bandwidth, buffers and timing management using hybrid scheduling of traffic with different priorities and guarantees are provided. In certain embodiments, a method of managing network scheduling and configuration comprises, for each transmitting end station, reserving one exclusive buffer for each virtual link to be transmitted from the transmitting end station; for each receiving end station, reserving exclusive buffers for each virtual link to be received at the receiving end station; and for each switch, reserving a exclusive buffer for each virtual link to be received at an input port of the switch. The method further comprises determining if each respective transmitting end station, receiving end station, and switch has sufficient capability to support the reserved buffers; and reporting buffer infeasibility if each respective transmitting end station, receiving end station, and switch does not have sufficient capability to support the reserved buffers.

Energy Efficient Medium Access Control Protocol for Clustered Wireless Sensor Networks with Adaptive Cross-Layer Scheduling.

PubMed

Sefuba, Maria; Walingo, Tom; Takawira, Fambirai

2015-09-18

This paper presents an Energy Efficient Medium Access Control (MAC) protocol for clustered wireless sensor networks that aims to improve energy efficiency and delay performance. The proposed protocol employs an adaptive cross-layer intra-cluster scheduling and an inter-cluster relay selection diversity. The scheduling is based on available data packets and remaining energy level of the source node (SN). This helps to minimize idle listening on nodes without data to transmit as well as reducing control packet overhead. The relay selection diversity is carried out between clusters, by the cluster head (CH), and the base station (BS). The diversity helps to improve network reliability and prolong the network lifetime. Relay selection is determined based on the communication distance, the remaining energy and the channel quality indicator (CQI) for the relay cluster head (RCH). An analytical framework for energy consumption and transmission delay for the proposed MAC protocol is presented in this work. The performance of the proposed MAC protocol is evaluated based on transmission delay, energy consumption, and network lifetime. The results obtained indicate that the proposed MAC protocol provides improved performance than traditional cluster based MAC protocols.