Test Bus Evaluation

DTIC Science & Technology

1998-04-01

selected is statistically based on the total number of faults and the failure rate distribution in the system under test. The fault set is also...implemented the BPM and system level emulation consolidation logic as well as statistics counters for cache misses and various bus transactions. These...instruction F22 Advanced Tactical Fighter FET Field Effect Transitor FF Flip-Flop FM Failures/Milhon hours C-3 FPGA Field Programmable Gate Array GET

Information management system study results. Volume 2: IMS study results appendixes

NASA Technical Reports Server (NTRS)

1971-01-01

Computer systems program specifications are presented for the modular space station information management system. These are the computer program contract end item, data bus system, data bus breadboard, and display interface adapter specifications. The performance, design, tests, and qualification requirements are established for the implementation of the information management system. For Vol. 1, see N72-19972.

Testing of Environmental Satellite Bus-Instrument Interfaces Using Engineering Models

NASA Technical Reports Server (NTRS)

Gagnier, Donald; Hayner, Rick; Nosek, Thomas; Roza, Michael; Hendershot, James E.; Razzaghi, Andrea I.

2004-01-01

This paper discusses the formulation and execution of a laboratory test of the electrical interfaces between multiple atmospheric scientific instruments and the spacecraft bus that carries them. The testing, performed in 2002, used engineering models of the instruments and the Aura spacecraft bus electronics. Aura is one of NASA s Earth Observatory System missions. The test was designed to evaluate the complex interfaces in the command and data handling subsystems prior to integration of the complete flight instruments on the spacecraft. A problem discovered during the flight integration phase of the observatory can cause significant cost and schedule impacts. The tests successfully revealed problems and led to their resolution before the full-up integration phase, saving significant cost and schedule. This approach could be beneficial for future environmental satellite programs involving the integration of multiple, complex scientific instruments onto a spacecraft bus.

Variability of particle number emissions from diesel and hybrid diesel-electric buses in real driving conditions.

PubMed

Sonntag, Darrell B; Gao, H Oliver; Holmén, Britt A

2008-08-01

A linear mixed model was developed to quantify the variability of particle number emissions from transit buses tested in real-world driving conditions. Two conventional diesel buses and two hybrid diesel-electric buses were tested throughout 2004 under different aftertreatments, fuels, drivers, and bus routes. The mixed model controlled the confounding influence of factors inherent to on-board testing. Statistical tests showed that particle number emissions varied significantly according to the after treatment, bus route, driver, bus type, and daily temperature, with only minor variability attributable to differences between fuel types. The daily setup and operation of the sampling equipment (electrical low pressure impactor) and mini-dilution system contributed to 30-84% of the total random variability of particle measurements among tests with diesel oxidation catalysts. By controlling for the sampling day variability, the model better defined the differences in particle emissions among bus routes. In contrast, the low particle number emissions measured with diesel particle filters (decreased by over 99%) did not vary according to operating conditions or bus type but did vary substantially with ambient temperature.

Single Axis Attitude Control and DC Bus Regulation with Two Flywheels

NASA Technical Reports Server (NTRS)

Kascak, Peter E.; Jansen, Ralph H.; Kenny, Barbara; Dever, Timothy P.

2002-01-01

A computer simulation of a flywheel energy storage single axis attitude control system is described. The simulation models hardware which will be experimentally tested in the future. This hardware consists of two counter rotating flywheels mounted to an air table. The air table allows one axis of rotational motion. An inertia DC bus coordinator is set forth that allows the two control problems, bus regulation and attitude control, to be separated. Simulation results are presented with a previously derived flywheel bus regulator and a simple PID attitude controller.

Testing of Environmental Satellite Bus-Instrument Interfaces Using Engineering Models

NASA Technical Reports Server (NTRS)

Gagnier, Don; Hayner, Rick; Roza, Michael; Nosek, Thomas; Razzaghi, Andrea

2004-01-01

This paper discusses the formulation and execution of a laboratory test of the electrical interfaces between multiple atmospheric science instruments and the spacecraft bus that carries them. The testing, performed in 2002, used engineering models of the instruments that will be flown on the Aura s p a c m and of the Aura spacecraft bus electronics. Aura is one of NASA's Earth Observing System @OS) Program missions managed by the Goddard Space Flight Center. The test was designed to evaluate the complex interfaces in the spacecraft and instrument command and data handling (C&DH) subsystems prior to integration of the complete flight instruments on the spacecraft. A problem discovered during (and not before) the flight hardware integration phase can cause significant cost and schedule impacts. The testing successfully surfaced problems and led to their resolution before the full-up integration phase, saving significant cost and schedule time. This approach could be used on future environmental satellite programs involving multiple, complex scientific instruments being integrated onto a bus.

Resonant AC power system proof-of-concept test program

NASA Technical Reports Server (NTRS)

Wappes, Loran J.

1986-01-01

Proof-of-concept testing was performed on a 20-kHz, resonant power system breadboard from 1981 through 1985. The testing began with the evaluation of a single, 1.0-kW resonant inverter and progressed to the testing of breadboard systems with higher power levels and more capability. The final breadboard configuration tested was a 25.0-kW breadboard with six inverters providing power to three user-interface modules over a 50-meter, 20-kHz bus. The breadboard demonstrated the ability to synchronize multiple resonant inverters to power a common bus. Single-phase and three-phase 20-kHz power distribution was demonstrated. Simple conversion of 20-kHz to dc and variable-frequency ac was demonstrated as was bidirectional power flow between 20-kHz and dc. Steady state measurements of efficiency, power-factor tolerance, and conducted emissions and conducted susceptibility were made. In addition, transient responses were recorded for such conditions as start up, shut down, load changes. The results showed the 20-kHz resonant system to be a desirable technology for a spacecraft power management and distribution system with multiple users and a utility-type bus.

Real life testing of a Hybrid PEM Fuel Cell Bus

NASA Astrophysics Data System (ADS)

Folkesson, Anders; Andersson, Christian; Alvfors, Per; Alaküla, Mats; Overgaard, Lars

Fuel cells produce low quantities of local emissions, if any, and are therefore one of the most promising alternatives to internal combustion engines as the main power source in future vehicles. It is likely that urban buses will be among the first commercial applications for fuel cells in vehicles. This is due to the fact that urban buses are highly visible for the public, they contribute significantly to air pollution in urban areas, they have small limitations in weight and volume and fuelling is handled via a centralised infrastructure. Results and experiences from real life measurements of energy flows in a Scania Hybrid PEM Fuel Cell Concept Bus are presented in this paper. The tests consist of measurements during several standard duty cycles. The efficiency of the fuel cell system and of the complete vehicle are presented and discussed. The net efficiency of the fuel cell system was approximately 40% and the fuel consumption of the concept bus is between 42 and 48% lower compared to a standard Scania bus. Energy recovery by regenerative braking saves up 28% energy. Bus subsystems such as the pneumatic system for door opening, suspension and brakes, the hydraulic power steering, the 24 V grid, the water pump and the cooling fans consume approximately 7% of the energy in the fuel input or 17% of the net power output from the fuel cell system. The bus was built by a number of companies in a project partly financed by the European Commission's Joule programme. The comprehensive testing is partly financed by the Swedish programme "Den Gröna Bilen" (The Green Car). A 50 kW el fuel cell system is the power source and a high voltage battery pack works as an energy buffer and power booster. The fuel, compressed hydrogen, is stored in two high-pressure stainless steel vessels mounted on the roof of the bus. The bus has a series hybrid electric driveline with wheel hub motors with a maximum power of 100 kW. Hybrid Fuel Cell Buses have a big potential, but there are still many issues to consider prior to full-scale commercialisation of the technology. These are related to durability, lifetime, costs, vehicle and system optimisation and subsystem design. A very important factor is to implement an automotive design policy in the design and construction of all components, both in the propulsion system as well as in the subsystems.

Changes in baseline concussion assessment scores following a school bus crash.

PubMed

Poland, Kristin M; McKay, Mary Pat; Zonfrillo, Mark R; Barth, Thomas H; Kaminski, Ronald

2016-09-01

The objective of this article is to present concussion assessment data for 30 male athletes prior to and after being involved in a large school bus crash. The athletes on the bus, all male and aged 14-18 years, were participants in their school's concussion management program that included baseline and postinjury testing using Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). This case study described changes in concussion assessment scores for 30 male athletes following a primarily frontal school bus crash. Data from the school's concussion management program, including baseline test data and postinjury assessment data, were reviewed. Athletes who required multiple postinjury assessments by the program were identified as having had significant cognitive changes as a result of the bus crash. Twenty-nine of 30 athletes were injured. One had lumbar compression fractures; others had various lacerations, abrasions, contusions, sprains, and nasal fractures. ImPACT data (postcrash) were available for all 30 athletes and 28 had available precrash baseline data. A total of 16 athletes (53.3%) had significant cognitive changes indicated by changes in their concussion assessment scores, some of which took months to improve. This case study highlights a unique opportunity to evaluate concussion assessment data from 30 male athletes involved in a high-speed school bus crash. Further, these data provide additional insight into assessing the effectiveness of current school bus occupant protection systems.

Application of new electro-optic technology to Space Station Freedom data management system

NASA Technical Reports Server (NTRS)

Husbands, C. R.; Girard, M. M.

1993-01-01

A low risk design methodology to permit the local bus structures to support increased data carrying capacities and to speed messages and data flow between nodes or stations on the Space Station Freedom Data Management System in anticipation of growing requirements was evaluated and recommended. The recommended design employs a collateral fiber optic technique that follows a NATO avionic standard that is developed, tested, and available. Application of this process will permit a potential 25 fold increase in data transfer performance on the local wire bus network with a fiber optic network, maintaining the functionality of the low-speed bus and supporting all of the redundant transmission and fault detection capabilities designed into the existing system. The application of wavelength division multiplexing (WDM) technology to both the local data bus and global data bus segments of the Data Management System to support anticipated additional highspeed data transmission requirements was also examined. Techniques were examined to provide a dual wavelength implementation of the fiber optic collateral networks. This dual wavelength implementation would permit each local bus to support two simultaneous high-speed transfers on the same fiber optic bus structure and operate within the limits of the existing protocol standard. A second WDM study examined the use of spectral sliced technology to provide a fourfold increase in the Fiber Distributed Data Interface (FDDI) global bus networks without requiring modifications to the existing installed cable plant. Computer simulations presented indicated that this data rate improvement can be achieved with commercially available optical components.

Deployment of Directory Service for IEEE N Bus Test System Information

NASA Astrophysics Data System (ADS)

Barman, Amal; Sil, Jaya

2008-10-01

Exchanging information over Internet and Intranet becomes a defacto standard in computer applications, among various users and organizations. Distributed system study, e-governance etc require transparent information exchange between applications, constituencies, manufacturers, and vendors. To serve these purposes database system is needed for storing system data and other relevant information. Directory service, which is a specialized database along with access protocol, could be the single solution since it runs over TCP/IP, supported by all POSIX compliance platforms and is based on open standard. This paper describes a way to deploy directory service, to store IEEE n bus test system data and integrating load flow program with it.

Available Transfer Capability Determination Using Hybrid Evolutionary Algorithm

NASA Astrophysics Data System (ADS)

Jirapong, Peeraool; Ongsakul, Weerakorn

2008-10-01

This paper proposes a new hybrid evolutionary algorithm (HEA) based on evolutionary programming (EP), tabu search (TS), and simulated annealing (SA) to determine the available transfer capability (ATC) of power transactions between different control areas in deregulated power systems. The optimal power flow (OPF)-based ATC determination is used to evaluate the feasible maximum ATC value within real and reactive power generation limits, line thermal limits, voltage limits, and voltage and angle stability limits. The HEA approach simultaneously searches for real power generations except slack bus in a source area, real power loads in a sink area, and generation bus voltages to solve the OPF-based ATC problem. Test results on the modified IEEE 24-bus reliability test system (RTS) indicate that ATC determination by the HEA could enhance ATC far more than those from EP, TS, hybrid TS/SA, and improved EP (IEP) algorithms, leading to an efficient utilization of the existing transmission system.

Autonomous Cryogenics Loading Operations Simulation Software: Knowledgebase Autonomous Test Engineer

NASA Technical Reports Server (NTRS)

Wehner, Walter S.

2012-01-01

The Simulation Software, KATE (Knowledgebase Autonomous Test Engineer), is used to demonstrate the automatic identification of faults in a system. The ACLO (Autonomous Cryogenics Loading Operation) project uses KATE to monitor and find faults in the loading of the cryogenics int o a vehicle fuel tank. The KATE software interfaces with the IHM (Integrated Health Management) systems bus to communicate with other systems that are part of ACLO. One system that KATE uses the IHM bus to communicate with is AIS (Advanced Inspection System). KATE will send messages to AIS when there is a detected anomaly. These messages include visual inspection of specific valves, pressure gauges and control messages to have AIS open or close manual valves. My goals include implementing the connection to the IHM bus within KATE and for the AIS project. I will also be working on implementing changes to KATE's Ul and implementing the physics objects in KATE that will model portions of the cryogenics loading operation.

AFTI/F16 Automated Maneuvering Attack System Test Reports/Special Technologies and Outlook.

DTIC Science & Technology

1986-07-11

Multiplex Data Bus A-A Air-To-Air A-S Air-to-Surface AFTI Advanced Fighter Technology Integration SYSTEM DESIGN AGL Above-Ground-Level AMAS Automated...Maneuvering Attack System Design requirements for the AFTI/F-16 are driven AMUX Avionics Multiplex Data Bus by realistic air combat scenarios and are...the avionics subsystem IFIM and avionics systems are single-thread, much of the sensed various flight control sensors. Additionally, along with data

Designing a New National Household Travel Survey : Innovations in Collecting and Analyzing Long-distance Travel Information

DOT National Transportation Integrated Search

2013-10-21

As part of its commitment to clean vehicle technologies, the City of Burbank tests a fuel cell bus in its mass transit system. BurbankBus, which provides transit services in and around the City of Burbank, California, has four fixedroute transit line...

Hydrogen-oxygen driven Zero Emissions bus drives around KSC Visitor Complex

NASA Technical Reports Server (NTRS)

1999-01-01

The Zero Emissions (ZE) transit bus tours the KSC Visitor Complex for a test ride. In the background are a mock-up orbiter named Explorer (left) and a stack of solid rocket boosters and external tank (right), typically used on Shuttle launches. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. The ZE bus is being used on tour routes at the KSC Visitor Complex for two days to introduce the public to the concept.

Transmission Loss Calculation using A and B Loss Coefficients in Dynamic Economic Dispatch Problem

NASA Astrophysics Data System (ADS)

Jethmalani, C. H. Ram; Dumpa, Poornima; Simon, Sishaj P.; Sundareswaran, K.

2016-04-01

This paper analyzes the performance of A-loss coefficients while evaluating transmission losses in a Dynamic Economic Dispatch (DED) Problem. The performance analysis is carried out by comparing the losses computed using nominal A loss coefficients and nominal B loss coefficients in reference with load flow solution obtained by standard Newton-Raphson (NR) method. Density based clustering method based on connected regions with sufficiently high density (DBSCAN) is employed in identifying the best regions of A and B loss coefficients. Based on the results obtained through cluster analysis, a novel approach in improving the accuracy of network loss calculation is proposed. Here, based on the change in per unit load values between the load intervals, loss coefficients are updated for calculating the transmission losses. The proposed algorithm is tested and validated on IEEE 6 bus system, IEEE 14 bus, system IEEE 30 bus system and IEEE 118 bus system. All simulations are carried out using SCILAB 5.4 (www.scilab.org) which is an open source software.

Aids to School Bus Design

NASA Technical Reports Server (NTRS)

1991-01-01

Navistar International Transportation Corporation, Chicago, IL, used three separate NASA-developed technologies in the design and testing of their 3000 Series Bus Chassis which was developed expressly for school bus applications. For structural analysis, they used the MSC/NASTRAN program which mathematically analyzes a design and predicts how it will hold up under stress. They also used the SPATE 9000 system for non-contact measurement of stress, load transfer mechanisms, detection of hidden flaws, and monitoring structural changes during fatigue testing. SPATE 9000 was based on infrared stress measurement technology developed by Langley Research Center. They also employed the Wyle Ride Quality Meter, which was developed by Langley to aid in passenger aircraft design by providing an accurate measurement of ride vibration and sound level. These numbers translate into a subjective discomfort level index. These technologies contribute to the company's 45-48 percent share of the school bus chassis market.

Public transit research: Rail, bus, and new technology, 1991. Transportation Research Record

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

Kassabian, N.C.; Tobias, A.G.; Crayton, L.

1991-01-01

The report contains: Image of Rail Transit; Train Operations Computer Simulation Case Study: Single-Tracking Operations for Philadelphia's Market-Frankford Subway Elevated Rail Rapid Transit Line; Transit Railcar Quantities: Scale Economies; Evaluation of Training Programs in Rail Transit: Its Role and Status; Methodology for Evaluating Out-of-Direction Bus Route Segments; Integration of Fixed- and Flexible-Route Bus Systems; Downtown Space for Buses--The Manhattan Experience; Implications of Transit Drug Testing and Maintenance Service Procurement for Small Urban and Rural Systems; Challenges for Integration of Alternative Fuels in the Transit Industry; Short History of the Transbay Transit Terminal and the Relocation of the San Francisco Greyhoundmore » Depot Thereto; Airport Development with Automated People Mover Systems; Review of Four Alternative Airport Terminal Passenger Mobility Systems.« less

Concept and Design of the Hybrid Sensor Bus System for Telecommunication Satellites

NASA Astrophysics Data System (ADS)

Hurni, Andreas; Tiefenbeck, Christoph; Manhart, Markus; Heyer, Heinz-Volker; Plattner, Markus; Putzer, Philipp; Roßner, Max; Koch, Alexander W.; Furano, Gianluca; McKenzie, Iain; Lam, King

2012-08-01

The Hybrid Sensor Bus (HSB) is a system for sensor interrogation in telecommunication satellites, which will be developed in the frame of the ESA ARTES program. The main target of the HSB system is the replacement of classical point-to-point wired sensors by sensors connected on bus networks. This will save mass and reduces efforts in assembly, integration and testing (AIT). The HSB system is able to manage an electrical I2C and a fiber-optical sensor network. The system consists of an intelligent power module, an electrical and a fiber-optical interrogator module in cold redundancy. Additional features of the HSB system are its modularity and the adaptability to different satellite platforms. The implementation of a HSB system allows platform manufacturers to build a more cost efficient satellite.This paper presents the concept and the design status of the HSB system.

77 FR 27277 - FTA Supplemental Fiscal Year 2012 Apportionments, Allocations, and Program Information

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-09

... allocates Section 5309 Bus and Bus Facilities funds to bus testing and the Fuel Cell program. Tables... Fuel Cell program. FTA will issue a supplemental notice at a later date if additional contract... allocated CA, GA, MA E2012-BUSP-018 Fuel Cell Bus Program..... $13,500,000 PA E2012-BUSP-019 Bus Testing 3...

Propulsion system for a motor vehicle using a bidirectional energy converter

DOEpatents

Tamor, Michael Alan; Gale, Allan Roy

1999-01-01

A motor vehicle propulsion system includes an electrical energy source and a traction motor coupled to receive electrical energy from the electrical energy source. The system also has a first bus provided electrical energy by the electrical energy source and a second bus of relatively lower voltage than the first bus. In addition, the system includes an electrically-driven source of reaction gas for the electrical energy source, the source of reaction gas coupled to receive electrical energy from the first bus. Also, the system has an electrical storage device coupled to the second bus for storing electrical energy at the lower voltage. The system also includes a bidirectional energy converter coupled to convert electrical energy from the first bus to the second bus and from the second bus to the first bus.

Energy management strategy based on fuzzy logic for a fuel cell hybrid bus

NASA Astrophysics Data System (ADS)

Gao, Dawei; Jin, Zhenhua; Lu, Qingchun

Fuel cell vehicles, as a substitute for internal-combustion-engine vehicles, have become a research hotspot for most automobile manufacturers all over the world. Fuel cell systems have disadvantages, such as high cost, slow response and no regenerative energy recovery during braking; hybridization can be a solution to these drawbacks. This paper presents a fuel cell hybrid bus which is equipped with a fuel cell system and two energy storage devices, i.e., a battery and an ultracapacitor. An energy management strategy based on fuzzy logic, which is employed to control the power flow of the vehicular power train, is described. This strategy is capable of determining the desired output power of the fuel cell system, battery and ultracapacitor according to the propulsion power and recuperated braking power. Some tests to verify the strategy were developed, and the results of the tests show the effectiveness of the proposed energy management strategy and the good performance of the fuel cell hybrid bus.

Damage Detection Sensitivity of a Vehicle-based Bridge Health Monitoring System

NASA Astrophysics Data System (ADS)

Miyamoto, Ayaho; Yabe, Akito; Lúcio, Válter J. G.

2017-05-01

As one solution to the problem for condition assessment of existing short and medium span (10-30m) reinforced/prestressed concrete bridges, a new monitoring method using a public bus as part of a public transit system (called “Bus monitoring system”) was proposed, along with safety indices, namely, “characteristic deflection”, which is relatively free from the influence of dynamic disturbances due to such factors as the roughness of the road surface, and a structural anomaly parameter. In this study, to evaluate the practicality of the newly developed bus monitoring system, it has been field-tested over a period of about four years by using an in-service fixed-route bus operating on a bus route in the city of Ube, Yamaguchi Prefecture, Japan. In here, although there are some useful monitoring methods for short and medium span bridges based on the qualitative or quantitative information, the sensitivity of damage detection was newly discussed for safety assessment based on long term health monitoring data. The verification results thus obtained are also described in this paper, and also evaluates the sensitivity of the “characteristic deflection”, which is a bridge (health) condition indicator used by the bus monitoring system, in damage detection. Sensitivity of “characteristic deflection” is verified by introducing artificial damage into a bridge that has ended its service life and is awaiting removal. Furthermore, the sensitivity of “characteristic deflection” is verified by 3D FEM analysis.

Harmonic Resonance in Power Transmission Systems due to the Addition of Shunt Capacitors

NASA Astrophysics Data System (ADS)

Patil, Hardik U.

Shunt capacitors are often added in transmission networks at suitable locations to improve the voltage profile. In this thesis, the transmission system in Arizona is considered as a test bed. Many shunt capacitors already exist in the Arizona transmission system and more are planned to be added. Addition of these shunt capacitors may create resonance conditions in response to harmonic voltages and currents. Such resonance, if it occurs, may create problematic issues in the system. It is main objective of this thesis to identify potential problematic effects that could occur after placing new shunt capacitors at selected buses in the Arizona network. Part of the objective is to create a systematic plan for avoidance of resonance issues. For this study, a method of capacitance scan is proposed. The bus admittance matrix is used as a model of the networked transmission system. The calculations on the admittance matrix were done using Matlab. The test bed is the actual transmission system in Arizona; however, for proprietary reasons, bus names are masked in the thesis copy intended for the public domain. The admittance matrix was obtained from data using the PowerWorld Simulator after equivalencing the 2016 summer peak load (planning case). The full Western Electricity Coordinating Council (WECC) system data were used. The equivalencing procedure retains only the Arizona portion of the WECC. The capacitor scan results for single capacitor placement and multiple capacitor placement cases are presented. Problematic cases are identified in the form of 'forbidden response. The harmonic voltage impact of known sources of harmonics, mainly large scale HVDC sources, is also presented. Specific key results for the study indicated include: (1) The forbidden zones obtained as per the IEEE 519 standard indicates the bus 10 to be the most problematic bus. (2) The forbidden zones also indicate that switching values for the switched shunt capacitor (if used) at bus 3 should be should be considered carefully to avoid resonance condition from existing. (3) The highest sensitivity of 0.0033 per unit for HVDC sources of harmonics was observed at bus 7 when all the HVDC sources were active at the same time.

Interprocessor bus switching system for simultaneous communication in plural bus parallel processing system

DOEpatents

Atac, R.; Fischler, M.S.; Husby, D.E.

1991-01-15

A bus switching apparatus and method for multiple processor computer systems comprises a plurality of bus switches interconnected by branch buses. Each processor or other module of the system is connected to a spigot of a bus switch. Each bus switch also serves as part of a backplane of a modular crate hardware package. A processor initiates communication with another processor by identifying that other processor. The bus switch to which the initiating processor is connected identifies and secures, if possible, a path to that other processor, either directly or via one or more other bus switches which operate similarly. If a particular desired path through a given bus switch is not available to be used, an alternate path is considered, identified and secured. 11 figures.

Interprocessor bus switching system for simultaneous communication in plural bus parallel processing system

DOEpatents

Atac, Robert; Fischler, Mark S.; Husby, Donald E.

1991-01-01

A bus switching apparatus and method for multiple processor computer systems comprises a plurality of bus switches interconnected by branch buses. Each processor or other module of the system is connected to a spigot of a bus switch. Each bus switch also serves as part of a backplane of a modular crate hardware package. A processor initiates communication with another processor by identifying that other processor. The bus switch to which the initiating processor is connected identifies and secures, if possible, a path to that other processor, either directly or via one or more other bus switches which operate similarly. If a particular desired path through a given bus switch is not available to be used, an alternate path is considered, identified and secured.

49 CFR 236.107 - Ground tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Ground tests. 236.107 Section 236.107...: All Systems Inspections and Tests; All Systems § 236.107 Ground tests. (a) Except as provided in paragraph (b) of this section, a test for grounds on each energy bus furnishing power to circuits, the...

49 CFR 236.107 - Ground tests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Ground tests. 236.107 Section 236.107...: All Systems Inspections and Tests; All Systems § 236.107 Ground tests. (a) Except as provided in paragraph (b) of this section, a test for grounds on each energy bus furnishing power to circuits, the...

KSC-99pp1252

NASA Image and Video Library

1999-10-25

The Zero Emissions (ZE) transit bus tours the KSC Visitor Complex for a test ride. In the background are a mock-up orbiter named Explorer (left) and a stack of solid rocket boosters and external tank (right), typically used on Shuttle launches. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product "exhaust" from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. The ZE bus is being used on tour routes at the KSC Visitor Complex for two days to introduce the public to the concept

Operationally Responsive Space Standard Bus Battery Thermal Balance Testing and Heat Dissipation Analysis

NASA Technical Reports Server (NTRS)

Marley, Mike

2008-01-01

The focus of this paper will be on the thermal balance testing for the Operationally Responsive Space Standard Bus Battery. The Standard Bus thermal design required that the battery be isolated from the bus itself. This required the battery to have its own thermal control, including heaters and a radiator surface. Since the battery was not ready for testing during the overall bus thermal balance testing, a separate test was conducted to verify the thermal design for the battery. This paper will discuss in detail, the test set up, test procedure, and results from this test. Additionally this paper will consider the methods taken to determine the heat dissipation of the battery during charge and discharge. It seems that the heat dissipation for Lithium Ion batteries is relatively unknown and hard to quantify. The methods used during test and the post test analysis to estimate the heat dissipation of the battery will be discussed.

49 CFR Appendix A to Part 665 - Tests To Be Performed at the Bus Testing Facility

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Tests To Be Performed at the Bus Testing Facility... Part 665—Tests To Be Performed at the Bus Testing Facility The eight tests to be performed on each vehicle are required by SAFETEA-LU and are based in part on tests described in the FTA report “First...

49 CFR Appendix A to Part 665 - Tests To Be Performed at the Bus Testing Facility

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Tests To Be Performed at the Bus Testing Facility... Part 665—Tests To Be Performed at the Bus Testing Facility The eight tests to be performed on each vehicle are required by SAFETEA-LU and are based in part on tests described in the FTA report “First...

Instrumentation & Data Acquisition System (D AS) Engineer

NASA Technical Reports Server (NTRS)

Jackson, Markus Deon

2015-01-01

The primary job of an Instrumentation and Data Acquisition System (DAS) Engineer is to properly measure physical phenomenon of hardware using appropriate instrumentation and DAS equipment designed to record data during a specified test of the hardware. A DAS system includes a CPU or processor, a data storage device such as a hard drive, a data communication bus such as Universal Serial Bus, software to control the DAS system processes like calibrations, recording of data and processing of data. It also includes signal conditioning amplifiers, and certain sensors for specified measurements. My internship responsibilities have included testing and adjusting Pacific Instruments Model 9355 signal conditioning amplifiers, writing and performing checkout procedures, writing and performing calibration procedures while learning the basics of instrumentation.

A Thermal Expert System (TEXSYS) development overview - AI-based control of a Space Station prototype thermal bus

NASA Technical Reports Server (NTRS)

Glass, B. J.; Hack, E. C.

1990-01-01

A knowledge-based control system for real-time control and fault detection, isolation and recovery (FDIR) of a prototype two-phase Space Station Freedom external thermal control system (TCS) is discussed in this paper. The Thermal Expert System (TEXSYS) has been demonstrated in recent tests to be capable of both fault anticipation and detection and real-time control of the thermal bus. Performance requirements were achieved by using a symbolic control approach, layering model-based expert system software on a conventional numerical data acquisition and control system. The model-based capabilities of TEXSYS were shown to be advantageous during software development and testing. One representative example is given from on-line TCS tests of TEXSYS. The integration and testing of TEXSYS with a live TCS testbed provides some insight on the use of formal software design, development and documentation methodologies to qualify knowledge-based systems for on-line or flight applications.

49 CFR Appendix A to Part 665 - Tests To Be Performed at the Bus Testing Facility

Code of Federal Regulations, 2010 CFR

2010-10-01

.... Because the operator will not become familiar with the detailed design of all new bus models that are tested, tests to determine the time and skill required to remove and reinstall an engine, a transmission... feasible to conduct statistical reliability tests. The detected bus failures, repair time, and the actions...

49 CFR Appendix A to Part 665 - Tests To Be Performed at the Bus Testing Facility

Code of Federal Regulations, 2011 CFR

2011-10-01

.... Because the operator will not become familiar with the detailed design of all new bus models that are tested, tests to determine the time and skill required to remove and reinstall an engine, a transmission... feasible to conduct statistical reliability tests. The detected bus failures, repair time, and the actions...

49 CFR Appendix A to Part 665 - Tests To Be Performed at the Bus Testing Facility

Code of Federal Regulations, 2013 CFR

2013-10-01

.... Because the operator will not become familiar with the detailed design of all new bus models that are tested, tests to determine the time and skill required to remove and reinstall an engine, a transmission... feasible to conduct statistical reliability tests. The detected bus failures, repair time, and the actions...

BBIS: Beacon Bus Information System

NASA Astrophysics Data System (ADS)

Kasim, Shahreen; Hafit, Hanayanti; Pei Juin, Kong; Afizah Afif, Zehan; Hashim, Rathiah; Ruslai, Husni; Jahidin, Kamaruzzaman; Syafwan Arshad, Mohammad

2016-11-01

Lack of bus information for example bus timetable, status of the bus and messy advertisement on bulletin board at the bus stop will give negative impact to tourist. Therefore, a real-time update bus information bulletin board provides all information needed so that passengers can save their bus information searching time. Supported with Android or iOS, Beacon Bus Information System (BBIS) provides bus information between Batu Pahat and Kluang area. BBIS is a system that implements physical web technology and interaction on demand. It built on Backend-as-a-Service, a cloud solution and Firebase non relational database as data persistence backend and syncs between user client in the real-time. People walk through bus stop with smart device and do not require any application. Bluetooth Beacon is used to achieve smart device's best performance of data sharing. Intellij IDEA 15 is one of the tools that that used to develop the BBIS system. Multi-language included front end and backend supported Integration development environment (IDE) helped to speed up integration process.

Numeric Modified Adomian Decomposition Method for Power System Simulations

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

Dimitrovski, Aleksandar D; Simunovic, Srdjan; Pannala, Sreekanth

This paper investigates the applicability of numeric Wazwaz El Sayed modified Adomian Decomposition Method (WES-ADM) for time domain simulation of power systems. WESADM is a numerical method based on a modified Adomian decomposition (ADM) technique. WES-ADM is a numerical approximation method for the solution of nonlinear ordinary differential equations. The non-linear terms in the differential equations are approximated using Adomian polynomials. In this paper WES-ADM is applied to time domain simulations of multimachine power systems. WECC 3-generator, 9-bus system and IEEE 10-generator, 39-bus system have been used to test the applicability of the approach. Several fault scenarios have been tested.more » It has been found that the proposed approach is faster than the trapezoidal method with comparable accuracy.« less

TMS communications software. Volume 2: Bus interface unit

NASA Technical Reports Server (NTRS)

Gregor, P. J.

1979-01-01

A data bus communication system to support the space shuttle's Trend Monitoring System (TMS) and to provide a basis for evaluation of the bus concept is described. Installation of the system included developing both hardware and software interfaces between the bus and the specific TMS computers and terminals. The software written for the microprocessor-based bus interface units is described. The software implements both the general bus communications protocol and also the specific interface protocols for the TMS computers and terminals.

On-line determination of transient stability status using multilayer perceptron neural network

NASA Astrophysics Data System (ADS)

Frimpong, Emmanuel Asuming; Okyere, Philip Yaw; Asumadu, Johnson

2018-01-01

A scheme to predict transient stability status following a disturbance is presented. The scheme is activated upon the tripping of a line or bus and operates as follows: Two samples of frequency deviation values at all generator buses are obtained. At each generator bus, the maximum frequency deviation within the two samples is extracted. A vector is then constructed from the extracted maximum frequency deviations. The Euclidean norm of the constructed vector is calculated and then fed as input to a trained multilayer perceptron neural network which predicts the stability status of the system. The scheme was tested using data generated from the New England test system. The scheme successfully predicted the stability status of all two hundred and five disturbance test cases.

Risk Assessment of Power System considering the CPS of Transformers

NASA Astrophysics Data System (ADS)

Zhou, Long; Peng, Zewu; Liu, Xindong; Li, Canbing; Chen, Can

2018-02-01

This paper constructs a risk assessment framework of power system for device-level information security, analyzes the typical protection configuration of power transformers, and takes transformer gas protection and differential protection as examples to put forward a method that analyzes the cyber security in electric power system, which targets transformer protection parameters. We estimate the risk of power system accounting for the cyber security of transformer through utilizing Monte Carlo method and two indexes, which are the loss of load probability and the expected demand not supplied. The proposed approach is tested with IEEE 9 bus system and IEEE 118 bus system.

Assessing transfer property and reliability of urban bus network based on complex network theory

NASA Astrophysics Data System (ADS)

Zhang, Hui; Zhuge, Cheng-Xiang; Zhao, Xiang; Song, Wen-Bo

Transfer reliability has an important impact on the urban bus network. The proportion of zero and one transfer time is a key indicator to measure the connectivity of bus networks. However, it is hard to calculate the transfer time between nodes because of the complicated network structure. In this paper, the topological structures of urban bus network in Jinan are constructed by space L and space P. A method to calculate transfer times between stations has been proposed by reachable matrix under space P. The result shows that it is efficient to calculate the transfer time between nodes in large networks. In order to test the transfer reliability, a node failure process has been built according to degree, clustering coefficient and betweenness centrality under space L and space P. The results show that the deliberate attack by betweenness centrality under space P is more effective compared with other five attack modes. This research could provide a power tool to find hub stations in bus networks and give a help for traffic manager to guarantee the normal operation of urban bus systems.

Effect of B20 and Low Aromatic Diesel on Transit Bus NOx Emissions Over Driving Cycles with a Range of Kinetic Intensity

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

Lammert, M. P.; McCormick, R. L.; Sindler, P.

2012-10-01

Oxides of nitrogen (NOx) emissions for transit buses for up to five different fuels and three standard transit duty cycles were compared to establish whether there is a real-world biodiesel NOx increase for transit bus duty cycles and engine calibrations. Six buses representing the majority of the current national transit fleet and including hybrid and selective catalyst reduction systems were tested on a heavy-duty chassis dynamometer with certification diesel, certification B20 blend, low aromatic (California Air Resources Board) diesel, low aromatic B20 blend, and B100 fuels over the Manhattan, Orange County and UDDS test cycles. Engine emissions certification level hadmore » the dominant effect on NOx; kinetic intensity was the secondary driving factor. The biodiesel effect on NOx emissions was not statistically significant for most buses and duty cycles for blends with certification diesel, except for a 2008 model year bus. CARB fuel had many more instances of a statistically significant effect of reducing NOx. SCR systems proved effective at reducing NOx to near the detection limit on all duty cycles and fuels, including B100. While offering a fuel economy benefit, a hybrid system significantly increased NOx emissions over a same year bus with a conventional drivetrain and the same engine.« less

Electrical system architecture

DOEpatents

Algrain, Marcelo C [Peoria, IL; Johnson, Kris W [Washington, IL; Akasam, Sivaprasad [Peoria, IL; Hoff, Brian D [East Peoria, IL

2008-07-15

An electrical system for a vehicle includes a first power source generating a first voltage level, the first power source being in electrical communication with a first bus. A second power source generates a second voltage level greater than the first voltage level, the second power source being in electrical communication with a second bus. A starter generator may be configured to provide power to at least one of the first bus and the second bus, and at least one additional power source may be configured to provide power to at least one of the first bus and the second bus. The electrical system also includes at least one power consumer in electrical communication with the first bus and at least one power consumer in electrical communication with the second bus.

HERMES travels by CAN bus

NASA Astrophysics Data System (ADS)

Waller, Lewis G.; Shortridge, Keith; Farrell, Tony J.; Vuong, Minh; Muller, Rolf; Sheinis, Andrew I.

2014-07-01

The new HERMES spectrograph represents the first foray by AAO into the use of commercial off-the-shelf industrial field bus technology for instrument control, and we regard the final system, with its relatively simple wiring requirements, as a great success. However, both software and hardware teams had to work together to solve a number of problems integrating the chosen CANopen/CAN bus system into our normal observing systems. A Linux system running in an industrial PC chassis ran the HERMES control software, using a PCI CAN bus interface connected to a number of distributed CANopen/CAN bus I/O devices and servo amplifiers. In the main, the servo amplifiers performed impressively, although some experimentation with homing algorithms was required, and we hit a significant hurdle when we discovered that we needed to disable some of the encoders used during observations; we learned a lot about how servo amplifiers respond when their encoders are turned off, and about how encoders react to losing power. The software was based around a commercial CANopen library from Copley Controls. Early worries about how this heavily multithreaded library would work with our standard data acquisition system led to the development of a very low-level CANopen software simulator to verify the design. This also enabled the software group to develop and test almost all the control software well in advance of the construction of the hardware. In the end, the instrument went from initial installation at the telescope to successful commissioning remarkably smoothly.

Research Electrical Distribution Bus | Energy Systems Integration Facility

Science.gov Websites

| NREL Research Electrical Distribution Bus Research Electrical Distribution Bus The research electrical distribution bus (REDB) is the heart of the Energy Systems Integration Facility electrical system throughout the laboratories. Photo of a technician performing maintenance on the Research Electrical

Electric School Bus Testing | Transportation Research | NREL

Science.gov Websites

Electric School Bus Evaluation Electric School Bus Evaluation Photo of children boarding school bus . NREL is evaluating the performance of electric and conventional school buses operated by two California school districts. Photo courtesy of School Bus Fleet Magazine NREL is evaluating the in-service

Baseline Testing of the Hybrid Electric Transit Bus

NASA Technical Reports Server (NTRS)

Brown, Jeffrey C.; Eichenberg, Dennis J.; Thompson, William K.

1999-01-01

A government, industry and academic cooperative has developed a Hybrid Electric Transit Bus (HETB). Goals of the program include doubling the fuel economy of city transit buses currently in service, and reducing emissions to one-tenth of EPA standards. Unique aspects of the vehicle's power system include the use of ultra-capacitors for the energy storage system and the planned use of a natural gas fueled turbogenerator, to be developed from a small jet engine. At over 17000 kg gross weight, this is the largest vehicle to use ultra-capacitor energy storage. A description of the HETB, the results of performance testing, and future vehicle development plans are the subject of this report.

Description of the PMAD systems test bed facility and data system

NASA Technical Reports Server (NTRS)

Trase, Larry; Fong, Don; Adkins, Vicki; Birchenough, Arthur

1992-01-01

The power management and distribution (PMAD) systems test bed facility, including the power sources and loads available, is discussed, and the PMAD data system (PDS) is described. The PDS controls the test-bed facility hardware, and monitors and records the electric power system control data bus and external data. The PDS architecture is discussed, and each of the subsystems is described.

49 CFR 234.249 - Ground tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Ground tests. 234.249 Section 234.249... EMERGENCY NOTIFICATION SYSTEMS Maintenance, Inspection, and Testing Inspections and Tests § 234.249 Ground tests. A test for grounds on each energy bus furnishing power to circuits that affect the safety of...

Evaluating the attractiveness of a new light rail extension: Testing simple change and displacement change hypotheses

PubMed Central

Brown, Barbara B.; Tribby, Calvin P.; Tharp, Doug; Flick, Kristi; Miller, Harvey J.; Smith, Ken R.; Jensen, Wyatt

2015-01-01

Many communities in the United States have been adding new light rail to bus-predominant public transit systems. However, there is disagreement as to whether opening light rail lines attracts new ridership or merely draws ridership from existing transit users. We study a new light rail line in Salt Lake City, Utah, USA, which is part of a complete street redevelopment. We utilize a pre-test post-test control group quasi-experimental design to test two different measures of ridership change. The first measure is calculated from stops along the light rail route; the second assumes that nearby bus stops might be displaced by the rail and calculates ridership change with those stops included as baseline. Both the simple measure (transit use changes on the complete street light rail corridor) and the “displacement” measure (transit use changes in the one-quarter mile catchment areas around new light rail stops) showed significant (p < .01) and substantial (677%) increases in transit passengers compared to pre-light rail bus users. In particular, the displacement analysis discredits a common challenge that when a new light rail line opens, most passengers are simply former bus riders whose routes were canceled in favor of light rail. The study suggests that light rail services can attract additional ridership to public transit systems. In addition, although pre-post control-group designs require time and effort, this project underscores the benefits of such quasi-experimental designs in terms of the strength of the inferences that can be drawn about the impacts of new transit infrastructure and services. PMID:26543329

Evaluating the attractiveness of a new light rail extension: Testing simple change and displacement change hypotheses.

PubMed

Werner, Carol M; Brown, Barbara B; Tribby, Calvin P; Tharp, Doug; Flick, Kristi; Miller, Harvey J; Smith, Ken R; Jensen, Wyatt

2016-01-01

Many communities in the United States have been adding new light rail to bus-predominant public transit systems. However, there is disagreement as to whether opening light rail lines attracts new ridership or merely draws ridership from existing transit users. We study a new light rail line in Salt Lake City, Utah, USA, which is part of a complete street redevelopment. We utilize a pre-test post-test control group quasi-experimental design to test two different measures of ridership change. The first measure is calculated from stops along the light rail route; the second assumes that nearby bus stops might be displaced by the rail and calculates ridership change with those stops included as baseline. Both the simple measure (transit use changes on the complete street light rail corridor) and the "displacement" measure (transit use changes in the one-quarter mile catchment areas around new light rail stops) showed significant ( p < .01) and substantial (677%) increases in transit passengers compared to pre-light rail bus users. In particular, the displacement analysis discredits a common challenge that when a new light rail line opens, most passengers are simply former bus riders whose routes were canceled in favor of light rail. The study suggests that light rail services can attract additional ridership to public transit systems. In addition, although pre-post control-group designs require time and effort, this project underscores the benefits of such quasi-experimental designs in terms of the strength of the inferences that can be drawn about the impacts of new transit infrastructure and services.

Design of a CAN bus interface for photoelectric encoder in the spaceflight camera

NASA Astrophysics Data System (ADS)

Sun, Ying; Wan, Qiu-hua; She, Rong-hong; Zhao, Chang-hai; Jiang, Yong

2009-05-01

In order to make photoelectric encoder usable in a spaceflight camera which adopts CAN bus as the communication method, CAN bus interface of the photoelectric encoder is designed in this paper. CAN bus interface hardware circuit of photoelectric encoder consists of CAN bus controller SJA 1000, CAN bus transceiver TJA1050 and singlechip. CAN bus interface controlling software program is completed in C language. A ten-meter shield twisted pair line is used as the transmission medium in the spaceflight camera, and speed rate is 600kbps.The experiments show that: the photoelectric encoder with CAN bus interface which has the advantages of more reliability, real-time, transfer rate and transfer distance overcomes communication line's shortcomings of classical photoelectric encoder system. The system works well in automatic measuring and controlling system.

Overview of drug and alcohol use among large truck and bus drivers, 2011–13.

DOT National Transportation Integrated Search

2016-12-01

This report provides a broad overview of drug and alcohol usage among large truck and bus drivers for 201113. Data sources for the overview are: testing results from motor carrier drug testing programs, roadside inspections on large trucks and bus...

77 FR 74452 - Bus Testing: Calculation of Average Passenger Weight and Test Vehicle Weight

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-14

... require FTA to work with bus manufacturers and transit agencies to establish a new pass/ fail standard for... buses from the current value of 150 pounds to a new value of 175 pounds. This increase was proposed to... new pass/fail standards that require a more comprehensive review of its overall bus testing program...

Massachusetts Fuel Cell Bus Project: Demonstrating a Total Transit Solution for Fuel Cell Electric Buses in Boston

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

The Federal Transit Administration's National Fuel Cell Bus Program focuses on developing commercially viable fuel cell bus technologies. Nuvera is leading the Massachusetts Fuel Cell Bus project to demonstrate a complete transit solution for fuel cell electric buses that includes one bus and an on-site hydrogen generation station for the Massachusetts Bay Transportation Authority (MBTA). A team consisting of ElDorado National, BAE Systems, and Ballard Power Systems built the fuel cell electric bus, and Nuvera is providing its PowerTap on-site hydrogen generator to provide fuel for the bus.

FAST BUS Test Box (LAIKA) (Engineering Materials)

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

Not Available

1983-01-01

The assembly drawing AD 135-518-00-RO, and the drawings referenced thereon, provide the data and specifications for constructing the LAIKA Test Box. Some drawings are not available, although they are listed on the material lists included. The assembly is a manual tester for FAST BUS modules, both masters and slaves. FAST BUS signals are generated by means of switches or push buttons and provide the state of the bus lines by lighting LED's. The box acts as either a master or slave - depending upon the module under test. It also acts as an ATC to test the arbitration logic ofmore » a master or ATC device.« less

Specifications and implementation of the RT MHD control system for the EC launcher of FTU

NASA Astrophysics Data System (ADS)

Galperti, C.; Alessi, E.; Boncagni, L.; Bruschi, A.; Granucci, G.; Grosso, A.; Iannone, F.; Marchetto, C.; Nowak, S.; Panella, M.; Sozzi, C.; Tilia, B.

2012-09-01

To perform real time plasma control experiments using EC heating waves by using the new fast launcher installed on FTU a dedicated data acquisition and elaboration system has been designed recently. A prototypical version of the acquisition/control system has been recently developed and will be tested on FTU machine in its next experimental campaign. The open-source framework MARTe (Multi-threaded Application Real-Time executor) on Linux/RTAI real-time operating system has been chosen as software platform to realize the control system. Standard open-architecture industrial PCs, based either on VME bus and CompactPCI bus equipped with standard input/output cards are the chosen hardware platform.

Optical technology for flight control systems

NASA Technical Reports Server (NTRS)

Mayanagi, M.

1986-01-01

Optical applications to the flight control system including optical data bus, sensors, and transducers are analyzed. Examples of optical data bus include airborne light optical fiber technology (ALOFT), F-5E, YA-7D, MIL-STD-1553 fiber optic data bus and NAL-optic data bus. This NAL-optic data bus is applied to STOL, and its characteristics are stressed. Principles and advantages of optical pulse-digital transducers are discussed.

Security awareness for public bus transportation : case studies of attacks against the Israeli public bus system [research brief].

DOT National Transportation Integrated Search

2012-03-01

Government regulators and transportation operators of public bus systems are concerned about terrorist attacks. Bus attacks in Israel between late September 2000 and the end of 2006, a period known as the Second Intifada, are particularly well known....

Loran-C flight test software

NASA Technical Reports Server (NTRS)

Nickum, J. D.

1978-01-01

The software package developed for the KIM-1 Micro-System and the Mini-L PLL receiver to simplify taking flight test data is described along with the address and data bus buffers used in the KIM-1 Micro-system. The interface hardware and timing are also presented to describe completely the software programs.

Stability improvement of wind turbine penetrated using power system stabilizer (PSS) on South Sulawesi transmission system

NASA Astrophysics Data System (ADS)

Siswanto, Agus; Gunadin, Indar Chaerah; Said, Sri Mawar; Suyuti, Ansar

2018-03-01

The purpose of this research is to improve the stability of interconnection of South Sulawesi system caused by penetration new wind turbine in Sidrap area on bus 2 and in Jeniponto area on bus 34. The method used in this research was via software Power System analysis Toolbox (PSAT) under MATLAB. In this research, there are two problems that are evaluated, the stability of the system before and after penetration wind turbine into the system South Sulawesi system. From the simulation result shows that penetration of wind turbine on bus 2 Sidrap, bus 37 Jeniponto give effect oscillation on the system. The oscillation was damped by installation of Power System Stabilizer (PSS) on bus 29 area Sungguminasa, that South Sulawesi system stable according to normal condition.

Electric bus systems.

DOT National Transportation Integrated Search

2017-04-01

Pure electric buses (EBs) offer an alternative fuel for the nations transit bus systems. To : evaluate EBs in a transit setting, this project investigated the five electric bus fleet of the : StarMetro transit system of the city of Tallahassee, FL...

Design of a steering stabilizer based on CAN bus

NASA Astrophysics Data System (ADS)

Zhan, Zhaomin; Yan, Yibin

2018-04-01

This design realizes a posture correction device of griping steering wheel based on CAN bus, which is embedded in the steering wheel of vehicles. The system aims to detect the drivers' abnormal griping postures and provides drivers with classification alerts, by combining the recorded griping postures data and the vehicle speed data that are obtained via the CAN bus. The warning information are automatically stored and retained in the device for 12 months. To enhance the alerting effect, the count of this warning message for both the latest month and the last 12 months are displayed on the dashboard panel. In addition to prevent itself from being blocked and self-detect any faults in advance, the appliance also provide a self-test function, which will communicate with the integrated instrument system in vehicle and do simulation test right after the vehicle power on. This appliance can help to urge and ensure drivers to operate the steering wheel correctly, effectively, and timely; prevent some typical incorrect behaviors which commonly happen along with the change of griping postures, such as the using cellphone, and ultimately, reduce the incidence of traffic accidents.

Forecast analysis of optical waveguide bus performance

NASA Technical Reports Server (NTRS)

Ledesma, R.; Rourke, M. D.

1979-01-01

Elements to be considered in the design of a data bus include: architecture; data rate; modulation, encoding, detection; power distribution requirements; protocol, work structure; bus reliability, maintainability; interterminal transmission medium; cost; and others specific to application. Fiber- optic data bus considerations for a 32 port transmissive star architecture, are discussed in a tutorial format. General optical-waveguide bus concepts, are reviewed. The electrical and optical performance of a 32 port transmissive star bus, and the effects of temperature on the performance of optical-waveguide buses are examined. A bibliography of pertinent references and the bus receiver test results are included.

TMS communications software. Volume 1: Computer interfaces

NASA Technical Reports Server (NTRS)

Brown, J. S.; Lenker, M. D.

1979-01-01

A prototype bus communications system, which is being used to support the Trend Monitoring System (TMS) as well as for evaluation of the bus concept is considered. Hardware and software interfaces to the MODCOMP and NOVA minicomputers are included. The system software required to drive the interfaces in each TMS computer is described. Documentation of other software for bus statistics monitoring and for transferring files across the bus is also included.

On Per-Phase Topology Control and Switching in Emerging Distribution Systems

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

Ding, Fei; Mousavi, Mirrasoul J.

This paper presents a new concept and approach for topology control and switching in distribution systems by extending the traditional circuit switching to laterals and single-phase loads. Voltage unbalance and other key performance indicators including voltage magnitudes, line loading, and energy losses are used to characterize and demonstrate the technical value of optimizing system topology on a per-phase basis in response to feeder conditions. The near-optimal per-phase topology control is defined as a series of hierarchical optimization problems. The proposed approach is respectively applied to IEEE 13-bus and 123-bus test systems for demonstration, which included the impact of integrating electricmore » vehicles (EVs) in the test circuit. It is concluded that the proposed approach can be effectively leveraged to improve voltage profiles with electric vehicles, the extent of which depends upon the performance of the base case without EVs.« less

Bus Testing Program

DOT National Transportation Integrated Search

1993-01-01

The Bus Testing Program of the Federal Transit Administration was established in response to the requirements of the Surface Transportation and Uniform Relocation Assistance Act (STURAA) of 1987. Under the program, testing is required on all new mode...

Analysis of Mesh Distribution Systems Considering Load Models and Load Growth Impact with Loops on System Performance

NASA Astrophysics Data System (ADS)

Kumar Sharma, A.; Murty, V. V. S. N.

2014-12-01

The distribution system is the final link between bulk power system and consumer end. A distinctive load flow solution method is used for analysis of the load flow of radial and weakly meshed network based on Kirchhoff's Current Law (KCL) and KVL. This method has excellent convergence characteristics for both radial as well as weakly meshed structure and is based on bus injection to branch current and branch-current to bus-voltage matrix. The main contribution of the paper is: (i) an analysis has been carried out for a weekly mesh network considering number of loops addition and its impact on the losses, kW and kVAr requirements from a system, and voltage profile, (ii) different load models, realistic ZIP load model and load growth impact on losses, voltage profile, kVA and kVAr requirements, (iii) impact of addition of loops on losses, voltage profile, kVA and kVAr requirements from substation, and (iv) comparison of system performance with radial distribution system. Voltage stability is a major concern in planning and operation of power systems. This paper also includes identifying the closeness critical bus which is the most sensitive to the voltage collapse in radial distribution networks. Node having minimum value of voltage stability index is the most sensitive node. Voltage stability index values are computed for meshed network with number of loops added in the system. The results have been obtained for IEEE 33 and 69 bus test system. The results have also been obtained for radial distribution system for comparison.

Electrical system architecture having high voltage bus

DOEpatents

Hoff, Brian Douglas [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL

2011-03-22

An electrical system architecture is disclosed. The architecture has a power source configured to generate a first power, and a first bus configured to receive the first power from the power source. The architecture also has a converter configured to receive the first power from the first bus and convert the first power to a second power, wherein a voltage of the second power is greater than a voltage of the first power, and a second bus configured to receive the second power from the converter. The architecture further has a power storage device configured to receive the second power from the second bus and deliver the second power to the second bus, a propulsion motor configured to receive the second power from the second bus, and an accessory motor configured to receive the second power from the second bus.

Advanced Vehicle Monitoring And Communication Systems For Bus Transit Benefits And Economic Feasibility

DOT National Transportation Integrated Search

1993-03-01

THIS REPORT ANALYZES THE FEASIBILITY OF ADVANCED VEHICLE MONITORING AND COMMUNICATION (AVM/C) SYSTEMS FOR BUS TRANSIT IN THE UNITED STATES. SUCH SYSTEMS ARE WIDELY USED IN EUROPE AND CANADA TO PROVIDE MORE RELIABLE AND EFFICIENT BUS SERVICES, BUT HAV...

Advanced Vehicle Monitoring And Communication Systems For Bus Transit, Benefits And Economic Feasibility

DOT National Transportation Integrated Search

1991-09-01

THIS REPORT ANALYZES THE FEASIBILITY OF ADVANCED VEHICLE MONITORING AND COMMUNICATION (AVM/C) SYSTEMS FOR BUS TRANSIT IN THE UNITED STATES. SUCH SYSTEMS ARE WIDELY USED IN EUROPE AND CANADA TO PROVIDE MORE RELIABLE AND EFFICIENT BUS SERVICES, BUT HAV...

Smart infrared inspection system field operational test : [technology brief].

DOT National Transportation Integrated Search

2014-04-01

One of the main goals of the Commercial Vehicle : Roadside Technology Corridor (CMVRTC) is to : support and evaluate the use of innovative : technologies that improve commercial truck and bus : safety. The Smart Infrared Inspection System : (SIRIS) w...

Evaluation of transit bus turn warning systems for pedestrians and cyclists.

DOT National Transportation Integrated Search

2015-05-01

As part of a cooperative agreement with the Federal Transit Administration (FTA), the Tri-County Metropolitan Transportation District of Oregon (TriMet) conducted a demonstration test of three commercially-available pedestrian turn warning systems fo...

Bus 54 -- Where are you? A school bus intelligent information system

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

Truett, L.F.; Moore, S.; Tonn, B.

1998-07-01

Although major accidents involving school buses are rare (only about 0.3% of all fatal crashes since 1986 are classified as school-bus-related), even minor accidents and breakdowns cause a great deal of parental anxiety. The objective of this research is to design an efficient, cost-effective, accurate, and secure system that will track individual school buses and communicate appropriate information to the school system`s central administration unit, to the school transportation administrator, and to parents of children on the bus. The greatest benefit of the proposed information system is that parents and officials can always know the location and condition (these conditionsmore » would vary depending on the needs of a particular school system) of the school buses. In case of an accident or mechanical problem, when emergency crews are needed, they can be dispatched almost immediately with a good understanding of the problem and the exact location of the bus. In addition to being able to track the bus while the child is on board, parents will be able to determine the location of their child`s bus prior to its arrival in the morning in order to prevent the child from needing to wait outside in inclement weather. The information available to parents can also be expanded to include maps of limited routes (e.g., snow routes). Basically, the Bus 54 concept consists of a bus component and a central data processing unit. Each bus will be outfitted with a global positioning satellite (GPS) device, a wireless communication device, and wireless data communication service. The central data processing unit will receive and process information from the buses and provide information access to parents and officials via an Internet link.« less

Preliminary Flight Results of the Microelectronics and Photonics Test Bed: NASA DR1773 Fiber Optic Data Bus Experiment

NASA Technical Reports Server (NTRS)

Jackson, George L.; LaBel, Kenneth A.; Marshall, Cheryl; Barth, Janet; Seidleck, Christina; Marshall, Paul

1998-01-01

NASA Goddard Spare Flight Center's (GSFC) Dual Rate 1773 (DR1773) Experiment on the Microelectronic and Photonic Test Bed (MPTB) has provided valuable information on the performance of the AS 1773 fiber optic data bus in the space radiation environment. Correlation of preliminary experiment data to ground based radiation test results show the AS 1773 bus is employable in future spacecraft applications requiring radiation tolerant communication links.

ALR-46 Computer Graphics System for the Robins Air Force Base Electronic Warfare Division Engineering Branch Laboratory.

DTIC Science & Technology

1981-12-01

CGS Funtional Requirements and System Configuration Introduction The first phase of any system development is to define requirements. The development of...between any two devices and the bus is in a master/slave relationship . During any bus operation, the bus master controls the bus when communicating with...illustrate the CASE statement of the PASCAL language. These extensions are mentioned to illustrate the relationships that the Warnier-Orr diagrams exhibit

Fault tolerant data management system

NASA Technical Reports Server (NTRS)

Gustin, W. M.; Smither, M. A.

1972-01-01

Described in detail are: (1) results obtained in modifying the onboard data management system software to a multiprocessor fault tolerant system; (2) a functional description of the prototype buffer I/O units; (3) description of modification to the ACADC and stimuli generating unit of the DTS; and (4) summaries and conclusions on techniques implemented in the rack and prototype buffers. Also documented is the work done in investigating techniques of high speed (5 Mbps) digital data transmission in the data bus environment. The application considered is a multiport data bus operating with the following constraints: no preferred stations; random bus access by all stations; all stations equally likely to source or sink data; no limit to the number of stations along the bus; no branching of the bus; and no restriction on station placement along the bus.

Design and test of data acquisition systems for the Medipix2 chip based on PC standard interfaces

NASA Astrophysics Data System (ADS)

Fanti, Viviana; Marzeddu, Roberto; Piredda, Giuseppina; Randaccio, Paolo

2005-07-01

We describe two readout systems for hybrid detectors using the Medipix2 single photon counting chip, developed within the Medipix Collaboration. The Medipix2 chip (256×256 pixels, 55 μm pitch) has an active area of about 2 cm 2 and is bump-bonded to a pixel semiconductor array of silicon or other semiconductor material. The readout systems we are developing are based on two widespread standard PC interfaces: parallel port and USB (Universal Serial Bus) version 1.1. The parallel port is the simplest PC interface even if slow and the USB is a serial bus interface present nowadays on all PCs and offering good performances.

Multi-channel temperature measurement system for automotive battery stack

NASA Astrophysics Data System (ADS)

Lewczuk, Radoslaw; Wojtkowski, Wojciech

2017-08-01

A multi-channel temperature measurement system for monitoring of automotive battery stack is presented in the paper. The presented system is a complete battery temperature measuring system for hybrid / electric vehicles that incorporates multi-channel temperature measurements with digital temperature sensors communicating through 1-Wire buses, individual 1-Wire bus for each sensor for parallel computing (parallel measurements instead of sequential), FPGA device which collects data from sensors and translates it for CAN bus frames. CAN bus is incorporated for communication with car Battery Management System and uses additional CAN bus controller which communicates with FPGA device through SPI bus. The described system can parallel measure up to 12 temperatures but can be easily extended in the future in case of additional needs. The structure of the system as well as particular devices are described in the paper. Selected results of experimental investigations which show proper operation of the system are presented as well.

Bus-stop Based Real Time Passenger Information System - Case Study Maribor

NASA Astrophysics Data System (ADS)

Čelan, Marko; Klemenčič, Mitja; Mrgole, Anamarija L.; Lep, Marjan

2017-10-01

Real time passenger information system is one of the key element of promoting public transport. For the successful implementation of real time passenger information systems, various components should be considered, such as: passenger needs and requirements, stakeholder involvement, technological solution for tracking, data transfer, etc. This article carrying out designing and evaluation of real time passenger information (RTPI) in the city of Maribor. The design phase included development of methodology for selection of appropriate macro and micro location of the real-time panel, development of a real-time passenger algorithm, definition of a technical specification, financial issues and time frame. The evaluation shows that different people have different requirements; therefore, the system should be adaptable to be used by various types of people, according to the age, the purpose of journey, experience of using public transport, etc. The average difference between perceived waiting time for a bus is 35% higher than the actual waiting time and grow with the headway increase. Experiences from Maribor have shown that the reliability of real time passenger system (from technical point of view) must be close to 100%, otherwise the system may have negative impact on passengers and may discourage the use of public transport. Among considered events of arrivals during the test period, 92% of all prediction were accurate. The cost benefit analysis has focused only on potential benefits from reduced perceived users waiting time and foreseen costs of real time information system in Maribor for 10 years’ period. Analysis shows that the optimal number for implementing real time passenger information system at the bus stops in Maribor is set on 83 bus stops (approx. 20 %) with the highest number of passenger. If we consider all entries at the chosen bus stops, the total perceived waiting time on yearly level could be decreased by about 60,000 hours.

The bus transit system : ITS underutilized potential

DOT National Transportation Integrated Search

1994-05-01

The bus system represents the most widely used transit mode. Upgraded bus services, primarily those which have partially or fully separated rights-of-way, represent a very cost-effective method to improve the balance between automobile and transit. M...

The crew activity planning system bus interface unit

NASA Technical Reports Server (NTRS)

Allen, M. A.

1979-01-01

The hardware and software designs used to implement a high speed parallel communications interface to the MITRE 307.2 kilobit/second serial bus communications system are described. The primary topic is the development of the bus interface unit.

Applications for improved inventory management for public transit systems

DOT National Transportation Integrated Search

2001-01-01

This report documents and presents the results of a Testing and Demonstration (T&D) Project on applications for improved inventory management for public transit systems. This project is a follow-up to an earlier study on inventory management for bus ...

TMS communications hardware. Volume 2: Bus interface unit

NASA Technical Reports Server (NTRS)

Brown, J. S.; Hopkins, G. T.

1979-01-01

A prototype coaxial cable bus communication system used in the Trend Monitoring System to interconnect intelligent graphics terminals to a host minicomputer is described. The terminals and host are connected to the bus through a microprocessor-based RF modem termed a Bus Interface Unit (BIU). The BIU hardware and the Carrier Sense Multiple Access Listen-While-Talk protocol used on the network are described.

A decentralized software bus based on IP multicas ting

NASA Technical Reports Server (NTRS)

Callahan, John R.; Montgomery, Todd

1995-01-01

We describe decentralized reconfigurable implementation of a conference management system based on the low-level Internet Protocol (IP) multicasting protocol. IP multicasting allows low-cost, world-wide, two-way transmission of data between large numbers of conferencing participants through the Multicasting Backbone (MBone). Each conference is structured as a software bus -- a messaging system that provides a run-time interconnection model that acts as a separate agent (i.e., the bus) for routing, queuing, and delivering messages between distributed programs. Unlike the client-server interconnection model, the software bus model provides a level of indirection that enhances the flexibility and reconfigurability of a distributed system. Current software bus implementations like POLYLITH, however, rely on a centralized bus process and point-to-point protocols (i.e., TCP/IP) to route, queue, and deliver messages. We implement a software bus called the MULTIBUS that relies on a separate process only for routing and uses a reliable IP multicasting protocol for delivery of messages. The use of multicasting means that interconnections are independent of IP machine addresses. This approach allows reconfiguration of bus participants during system execution without notifying other participants of new IP addresses. The use of IP multicasting also permits an economy of scale in the number of participants. We describe the MULITIBUS protocol elements and show how our implementation performs better than centralized bus implementations.

Transit bus stop pedestrian warning application : acceptance test plan : final report.

DOT National Transportation Integrated Search

2016-10-14

This document is the Acceptance Test Plan for the Transit Bus Stop Pedestrian Warning (TSPW) application. This report describes the test and demonstration plan to verify that the application meets its functional and performance requirements.

A new bus lane on urban expressway with no-bay bus stop

NASA Astrophysics Data System (ADS)

Tian, Zhao; Jia, Limin

2016-01-01

The sharp increase in residents and vehicles causes heavy traffic pressure in many cities. To ease traffic congestion, it has been the common sense that we should develop public transit system. The priority of the bus appears particularly necessary with the rapid development of the public transport system. The bus lane is an important embodiment of the bus priority. Focusing on the problem of the unreasonable dedicated bus lane (DBL) under the lower ratio of buses, this paper proposed a new bus lane with limited physical length. And this bus lane can reduce the lane-changing conflict caused by the buses and cars running on roads without bus lanes. Based on the cellular automata (CA) traffic flow model and the lane-changing behavior of the vehicle including the optional lane-changing and the mandatory lane-changing, a three-lane traffic model with an isolated no-bay bus stop is proposed. The ordinary three-lane traffic without a bus lane and the cases of traffic with a DBL or the proposed bus lane are simulated, and the comparisons in the form of the fundamental diagrams are made among them. It is shown that the no-bay bus stop can act as a bottleneck on the traffic flow because of the mandatory lane-changing behavior. Under a certain ratio of the bus number to the total vehicles number, (1) the traffic with the proposed bus lane has less lane-changing conflict and can provide higher traffic capacity than the ordinary traffic without a bus lane, (2) compared with the DBL, the proposed bus lane is advantageous in easing congestion on the ordinary lanes when the traffic flow is high and can avoid unreasonable allocation of the road resources.

49 CFR 665.13 - Test report and manufacturer certification.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Test report and manufacturer certification. 665.13 Section 665.13 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BUS TESTING Bus Testing Procedures § 665.13 Test report and manufacturer certification. (a) Upon...

Optimal Congestion Management in Electricity Market Using Particle Swarm Optimization with Time Varying Acceleration Coefficients

NASA Astrophysics Data System (ADS)

Boonyaritdachochai, Panida; Boonchuay, Chanwit; Ongsakul, Weerakorn

2010-06-01

This paper proposes an optimal power redispatching approach for congestion management in deregulated electricity market. Generator sensitivity is considered to indicate the redispatched generators. It can reduce the number of participating generators. The power adjustment cost and total redispatched power are minimized by particle swarm optimization with time varying acceleration coefficients (PSO-TVAC). The IEEE 30-bus and IEEE 118-bus systems are used to illustrate the proposed approach. Test results show that the proposed optimization scheme provides the lowest adjustment cost and redispatched power compared to the other schemes. The proposed approach is useful for the system operator to manage the transmission congestion.

Placement of Synchronized Measurements for Power System Observability during Cascaded Outages

NASA Astrophysics Data System (ADS)

Thirugnanasambandam, Venkatesh; Jain, Trapti

2017-11-01

Cascaded outages often result in power system islanding followed by a blackout and therefore considered as a severe disturbance. Maintaining the observability of each island may help in taking proper control actions to preserve the stability of individual islands thus, averting system collapse. With this intent, a strategy for placement of synchronized measurements, which can be obtained from phasor measurement units (PMU), has been proposed in this paper to keep the system observable during cascaded outages also. Since, all the cascaded failures may not lead to islanding situations, therefore, failures leading to islanding as well as non-islanding situations have been considered. A topology based algorithm has been developed to identify the islanding/non-islanding condition created by a particular cascaded event. Additional contingencies such as single line loss and single PMU failure have also been considered after the occurrence of cascaded events. The proposed method is further extended to incorporate the measurement redundancy, which is desirable for a reliable state estimation. The proposed scheme is tested on IEEE 14-bus, IEEE 30-bus and a practical Indian 246-bus networks. The numerical results ensure the observability of the power system under system intact as well as during cascaded islanding and non-islanding disturbances.

Mars Reconnaissance Orbiter Taking Shape

NASA Image and Video Library

2004-08-09

Lockheed Martin Space Systems engineer Terry Kampmann left and lead technician Jack Farmerie work on assembly and test of NASA Mars Reconnaissance Orbiter spacecraft bus in a cleanroom at the company Denver facility.

Connecticut DOT statewide bus system study : executive summary

DOT National Transportation Integrated Search

2000-07-01

The Connecticut Statewide Bus System Study has been undertaken to ensure that bus transit in Connecticut serves continuing needs in the most efficient manner possible. The Study has taken a comprehensive look at the state's twenty urban and rural tra...

Intelligent transportation systems field operational test cross-cutting study : emergency notification and response

DOT National Transportation Integrated Search

2000-08-01

Transportation is vital to the social and economic health of the nation. Surface transportation systems ? the networks of highways, local streets, bus routes, and rail lines ? are the ties that bind communities and facilitate commerce. Despite the fa...

Road safety issues for bus transport management.

PubMed

Cafiso, Salvatore; Di Graziano, Alessandro; Pappalardo, Giuseppina

2013-11-01

Because of the low percentage of crashes involving buses and the assumption that public transport improves road safety by reducing vehicular traffic, public interest in bus safety is not as great as that in the safety of other types of vehicles. It is possible that less attention is paid to the significance of crashes involving buses because the safety level of bus systems is considered to be adequate. The purpose of this study was to evaluate the knowledge and perceptions of bus managers with respect to safety issues and the potential effectiveness of various technologies in achieving higher safety standards. Bus managers were asked to give their opinions on safety issues related to drivers (training, skills, performance evaluation and behaviour), vehicles (maintenance and advanced devices) and roads (road and traffic safety issues) in response to a research survey. Kendall's algorithm was used to evaluate the level of concordance. The results showed that the majority of the proposed items were considered to have great potential for improving bus safety. The data indicated that in the experience of the participants, passenger unloading and pedestrians crossing near bus stops are the most dangerous actions with respect to vulnerable users. The final results of the investigation showed that start inhibition, automatic door opening, and the materials and internal architecture of buses were considered the items most strongly related to bus passenger safety. Brake assistance and vehicle monitoring systems were also considered to be very effective. With the exception of driver assistance systems for passenger and pedestrian safety, the perceptions of the importance of other driver assistance systems for vehicle monitoring and bus safety were not unanimous among the bus company managers who participated in this survey. The study results showed that the introduction of new technologies is perceived as an important factor in improving bus safety, but a better understanding of their actual effectiveness and related risk factor avoidance must be developed to permit their useful implementation in bus fleets. Copyright © 2013 Elsevier Ltd. All rights reserved.

Global system data bus using the Digital Autonomous Terminal Access Communication protocol

NASA Technical Reports Server (NTRS)

Holmes, David C. E.

1986-01-01

Modern digital avionic systems with distributed processing require networking to connect the many elements. Digital Autonomous Terminal Access Communication (DATAC) is one of many such networks. DATAC has been implemented on the Transport Systems Research Vehicle (TSRV), a Boeing 737 aircraft operated by the National Aeronautics and Space Administration's Advanced Transport Operating Systems Program Office (ATOPS). This paper presents the TSRV implementation of the DATAC bus, a description of the DATAC system, a synchronization mechanism, details of data flow throughout the system, and a discussion of the modes available with DATAC. Numerous flight tests have been conducted using DATAC as the only means of communication between systems with outstanding results. DATAC is now an integral part of the TSRV and is expected to satisfy near term as well as future requirements for growth and flexibility.

An evaluation of the Shirley Highway Express-Bus-on-Freeway Demonstration Project.

DOT National Transportation Integrated Search

1973-01-01

The Shirley Highway Express-Bus-on-Freeway Demonstration Project was initiated to test the hypothesis that the provision of rapid and convenient bus service over an exclusive lane would attract significant numbers of automobile passengers. Such a div...

76 FR 28947 - Bus Testing: Calculation of Average Passenger Weight and Test Vehicle Weight, and Public Meeting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-19

...-0015] RIN 2132-AB01 Bus Testing: Calculation of Average Passenger Weight and Test Vehicle Weight, and... of proposed rulemaking (NPRM) regarding the calculation of average passenger weights and test vehicle... passenger weights and actual transit vehicle loads. Specifically, FTA proposed to change the average...

Impact of Distribution Feeders that do not have Voltage Regulators on the number of Charged Electric Vehicles using IEEE 34 Bus Test Feeder

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

Allehyani, Ahmed; Beshir, Mohammed

Voltage regulators help maintain an acceptable voltage profile for the system. This paper discusses the effect of installing voltage regulators to the system to fix the voltage drop resulting from the electrical vehicles loading increase when they are being charged. The effect will be studied in the afternoon, when the peak load occurs, using the IEEE 34 bus test feeder. First, only one spot node is used to charge the electric vehicles while a voltage regulator is present. Second, five spot nodes are loaded at the same time to charge the electric vehicles while voltage regulators are installed at eachmore » node. After that, the impact of electric vehicles on distribution feeders that do not have voltage regulators will appear.« less

Spacecraft design project: High temperature superconducting infrared imaging satellite

NASA Technical Reports Server (NTRS)

1991-01-01

The High Temperature Superconductor Infrared Imaging Satellite (HTSCIRIS) is designed to perform the space based infrared imaging and surveillance mission. The design of the satellite follows the black box approach. The payload is a stand alone unit, with the spacecraft bus designed to meet the requirements of the payload as listed in the statement of work. Specifications influencing the design of the spacecraft bus were originated by the Naval Research Lab. A description of the following systems is included: spacecraft configuration, orbital dynamics, radio frequency communication subsystem, electrical power system, propulsion, attitude control system, thermal control, and structural design. The issues of testing and cost analysis are also addressed. This design project was part of the course Advanced Spacecraft Design taught at the Naval Postgraduate School.

Implementation of Ada protocols on Mil-STD-1553 B data bus

NASA Technical Reports Server (NTRS)

Ruhman, Smil; Rosemberg, Flavia

1986-01-01

Standardization activity of data communication in avionic systems started in 1968 for the purpose of total system integration and the elimination of heavy wire bundles carrying signals between various subassemblies. The growing complexity of avionic systems is straining the capabilities of MIL-STD-1553 B (first issued in 1973), but a much greater challenge to it is posed by Ada, the standard language adopted for real-time, computer embedded-systems. Hardware implementation of Ada communication protocols in a contention/token bus or token ring network is proposed. However, during the transition period when the current command/response multiplex data bus is still flourishing and the development environment for distributed multi-computer Ada systems is as yet lacking, a temporary accomodation of the standard language with the standard bus could be very useful and even highly desirable. By concentrating all status informtion and decisions at the bus controller, it was found to be possible to construct an elegant and efficient harware impelementation of the Ada protocols at the bus interface. This solution is discussed.

Optimal placement and sizing of wind / solar based DG sources in distribution system

NASA Astrophysics Data System (ADS)

Guan, Wanlin; Guo, Niao; Yu, Chunlai; Chen, Xiaoguang; Yu, Haiyang; Liu, Zhipeng; Cui, Jiapeng

2017-06-01

Proper placement and sizing of Distributed Generation (DG) in distribution system can obtain maximum potential benefits. This paper proposes quantum particle swarm algorithm (QPSO) based wind turbine generation unit (WTGU) and photovoltaic (PV) array placement and sizing approach for real power loss reduction and voltage stability improvement of distribution system. Performance modeling of wind and solar generation system are described and classified into PQ\\PQ (V)\\PI type models in power flow. Considering the WTGU and PV based DGs in distribution system is geographical restrictive, the optimal area and DG capacity limits of each bus in the setting area need to be set before optimization, the area optimization method is proposed . The method has been tested on IEEE 33-bus radial distribution systems to demonstrate the performance and effectiveness of the proposed method.

TLBO based Voltage Stable Environment Friendly Economic Dispatch Considering Real and Reactive Power Constraints

NASA Astrophysics Data System (ADS)

Verma, H. K.; Mafidar, P.

2013-09-01

In view of growing concern towards environment, power system engineers are forced to generate quality green energy. Hence the economic dispatch (ED) aims at the power generation to meet the load demand at minimum fuel cost with environmental and voltage constraints along with essential constraints on real and reactive power. The emission control which reduces the negative impact on environment is achieved by including the additional constraints in ED problem. Presently, the power system mostly operates near its stability limits, therefore with increased demand the system faces voltage problem. The bus voltages are brought within limit in the present work by placement of static var compensator (SVC) at weak bus which is identified from bus participation factor. The optimal size of SVC is determined by univariate search method. This paper presents the use of Teaching Learning based Optimization (TLBO) algorithm for voltage stable environment friendly ED problem with real and reactive power constraints. The computational effectiveness of TLBO is established through test results over particle swarm optimization (PSO) and Big Bang-Big Crunch (BB-BC) algorithms for the ED problem.

Clustering method for counting passengers getting in a bus with single camera

NASA Astrophysics Data System (ADS)

Yang, Tao; Zhang, Yanning; Shao, Dapei; Li, Ying

2010-03-01

Automatic counting of passengers is very important for both business and security applications. We present a single-camera-based vision system that is able to count passengers in a highly crowded situation at the entrance of a traffic bus. The unique characteristics of the proposed system include, First, a novel feature-point-tracking- and online clustering-based passenger counting framework, which performs much better than those of background-modeling-and foreground-blob-tracking-based methods. Second, a simple and highly accurate clustering algorithm is developed that projects the high-dimensional feature point trajectories into a 2-D feature space by their appearance and disappearance times and counts the number of people through online clustering. Finally, all test video sequences in the experiment are captured from a real traffic bus in Shanghai, China. The results show that the system can process two 320×240 video sequences at a frame rate of 25 fps simultaneously, and can count passengers reliably in various difficult scenarios with complex interaction and occlusion among people. The method achieves high accuracy rates up to 96.5%.

Bus-based park-and-ride system: a stochastic model on multimodal network with congestion pricing schemes

NASA Astrophysics Data System (ADS)

Liu, Zhiyuan; Meng, Qiang

2014-05-01

This paper focuses on modelling the network flow equilibrium problem on a multimodal transport network with bus-based park-and-ride (P&R) system and congestion pricing charges. The multimodal network has three travel modes: auto mode, transit mode and P&R mode. A continuously distributed value-of-time is assumed to convert toll charges and transit fares to time unit, and the users' route choice behaviour is assumed to follow the probit-based stochastic user equilibrium principle with elastic demand. These two assumptions have caused randomness to the users' generalised travel times on the multimodal network. A comprehensive network framework is first defined for the flow equilibrium problem with consideration of interactions between auto flows and transit (bus) flows. Then, a fixed-point model with unique solution is proposed for the equilibrium flows, which can be solved by a convergent cost averaging method. Finally, the proposed methodology is tested by a network example.

System Critical Design Audit (CDA). Books 1, 2 and 3; [Small Satellite Technology Initiative (SSTI Lewis Spacecraft Program)

NASA Technical Reports Server (NTRS)

1995-01-01

Small Satellite Technology Initiative (SSTI) Lewis Spacecraft Program is evaluated. Spacecraft integration, test, launch, and spacecraft bus are discussed. Payloads and technology demonstrations are presented. Mission data management system and ground segment are also addressed.

Distributed control system for parallel-connected DC boost converters

DOEpatents

Goldsmith, Steven

2017-08-15

The disclosed invention is a distributed control system for operating a DC bus fed by disparate DC power sources that service a known or unknown load. The voltage sources vary in v-i characteristics and have time-varying, maximum supply capacities. Each source is connected to the bus via a boost converter, which may have different dynamic characteristics and power transfer capacities, but are controlled through PWM. The invention tracks the time-varying power sources and apportions their power contribution while maintaining the DC bus voltage within the specifications. A central digital controller solves the steady-state system for the optimal duty cycle settings that achieve a desired power supply apportionment scheme for a known or predictable DC load. A distributed networked control system is derived from the central system that utilizes communications among controllers to compute a shared estimate of the unknown time-varying load through shared bus current measurements and bus voltage measurements.

Fault-tolerant processing system

NASA Technical Reports Server (NTRS)

Palumbo, Daniel L. (Inventor)

1996-01-01

A fault-tolerant, fiber optic interconnect, or backplane, which serves as a via for data transfer between modules. Fault tolerance algorithms are embedded in the backplane by dividing the backplane into a read bus and a write bus and placing a redundancy management unit (RMU) between the read bus and the write bus so that all data transmitted by the write bus is subjected to the fault tolerance algorithms before the data is passed for distribution to the read bus. The RMU provides both backplane control and fault tolerance.

A software bus for thread objects

NASA Technical Reports Server (NTRS)

Callahan, John R.; Li, Dehuai

1995-01-01

The authors have implemented a software bus for lightweight threads in an object-oriented programming environment that allows for rapid reconfiguration and reuse of thread objects in discrete-event simulation experiments. While previous research in object-oriented, parallel programming environments has focused on direct communication between threads, our lightweight software bus, called the MiniBus, provides a means to isolate threads from their contexts of execution by restricting communications between threads to message-passing via their local ports only. The software bus maintains a topology of connections between these ports. It routes, queues, and delivers messages according to this topology. This approach allows for rapid reconfiguration and reuse of thread objects in other systems without making changes to the specifications or source code. A layered approach that provides the needed transparency to developers is presented. Examples of using the MiniBus are given, and the value of bus architectures in building and conducting simulations of discrete-event systems is discussed.

Dynamically reconfigurable photovoltaic system

DOEpatents

Okandan, Murat; Nielson, Gregory N.

2016-05-31

A PV system composed of sub-arrays, each having a group of PV cells that are electrically connected to each other. A power management circuit for each sub-array has a communications interface and serves to connect or disconnect the sub-array to a programmable power grid. The power grid has bus rows and bus columns. A bus management circuit is positioned at a respective junction of a bus column and a bus row and is programmable through its communication interface to connect or disconnect a power path in the grid. As a result, selected sub-arrays are connected by selected power paths to be in parallel so as to produce a low system voltage, and, alternately in series so as to produce a high system voltage that is greater than the low voltage by at least a factor of ten.

Dynamically reconfigurable photovoltaic system

DOEpatents

Okandan, Murat; Nielson, Gregory N.

2016-12-27

A PV system composed of sub-arrays, each having a group of PV cells that are electrically connected to each other. A power management circuit for each sub-array has a communications interface and serves to connect or disconnect the sub-array to a programmable power grid. The power grid has bus rows and bus columns. A bus management circuit is positioned at a respective junction of a bus column and a bus row and is programmable through its communication interface to connect or disconnect a power path in the grid. As a result, selected sub-arrays are connected by selected power paths to be in parallel so as to produce a low system voltage, and, alternately in series so as to produce a high system voltage that is greater than the low voltage by at least a factor of ten.

46 CFR 112.05-3 - Main-emergency bus-tie.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS General § 112.05-3 Main-emergency bus-tie. Each bus-tie between a main switchboard... other source of electric power, except for interlock systems for momentary transfer of loads; and (c) If...

46 CFR 112.05-3 - Main-emergency bus-tie.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS General § 112.05-3 Main-emergency bus-tie. Each bus-tie between a main switchboard... other source of electric power, except for interlock systems for momentary transfer of loads; and (c) If...

46 CFR 112.05-3 - Main-emergency bus-tie.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS General § 112.05-3 Main-emergency bus-tie. Each bus-tie between a main switchboard... other source of electric power, except for interlock systems for momentary transfer of loads; and (c) If...

46 CFR 112.05-3 - Main-emergency bus-tie.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS General § 112.05-3 Main-emergency bus-tie. Each bus-tie between a main switchboard... other source of electric power, except for interlock systems for momentary transfer of loads; and (c) If...

Security awareness for public bus transportation : case studies of attacks against the Israeli public bus system.

DOT National Transportation Integrated Search

2012-03-01

This report presents 16 case studies of attacks planned or carried out against Israeli bus targets, along with statistical data on the number, frequency, and lethality of attacks against bus targets that have taken place in Israel since 1970 and duri...

Harmonizing Automatic Test System Assets, Drivers, and Control Methodologies

DTIC Science & Technology

1999-07-18

ORGANIZATION PRINCIPAL AREAS OF INTEREST TO ATS NAME 1394 TA Firewire Trade Association Defining high speed bus protocol Active Group Accelerating ActiveX ...System Assets, Drivers, and Control Methodologies 17 JUL, 1999 component is a diagonal matrix containing scaling values such that when the three

Updating the school bus standard vehicle for load rating Alabama bridges.

DOT National Transportation Integrated Search

2010-06-01

The objective of this project is to identify a representative school bus (weight and axle spacing) for load rating highway bridges. The ALDOT Bridge Rating and Load Test Section currently uses a 12.5-ton school bus (four tons on the front axle and 8....

Performance Evaluation of UHF RFID Technologies for Real-Time Bus Recognition in the Taipei Bus Station

PubMed Central

Own, Chung-Ming; Lee, Da-Sheng; Wang, Ti-Ho; Wang, De-Jun; Ting, Yu-Lun

2013-01-01

Transport stations such as airports, ports, and railways have adopted blocked-type pathway management to process and control travel systems in a one-directional manner. However, this excludes highway transportation where large buses have great variability and mobility; thus, an instant influx of numerous buses increases risks and complicates station management. Focusing on Taipei Bus Station, this study employed RFID technology to develop a system platform integrated with modern information technology that has numerous characteristics. This modern information technology comprised the following systems: ultra-high frequency (UHF) radio-frequency identification (RFID), ultrasound and license number identification, and backstage graphic controls. In conclusion, the system enabled management, bus companies, and passengers to experience the national bus station's new generation technology, which provides diverse information and synchronization functions. Furthermore, this technology reached a new milestone in the energy-saving and efficiency-increasing performance of Taiwan's buses. PMID:23778192

Dispersion of CNG Following a High-Pressure Release

DOT National Transportation Integrated Search

1996-05-01

This report discusses the results of tests to determine the dispersive behavior of compressed natural gas (CNG) when released in enclosed areas such as transit bus facility, and presents the Volpe National Transportation Systems Center's (VNTSC) conc...

Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

PubMed Central

Kong, Y. S.; Omar, M. Z.; Chua, L. B.; Abdullah, S.

2013-01-01

This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability. PMID:24298209

Explicit nonlinear finite element geometric analysis of parabolic leaf springs under various loads.

PubMed

Kong, Y S; Omar, M Z; Chua, L B; Abdullah, S

2013-01-01

This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

Analysis of a diesel-electric hybrid urban bus system

NASA Astrophysics Data System (ADS)

Marr, W. W.; Sekar, R. R.; Ahlheim, M. C.

A hybrid bus powered by a diesel engine and a battery pack was analyzed over an idealized bus-driving cycle in Chicago. Three hybrid configurations, two parallel and one series, were evaluated. The results indicate that the fuel economy of a hybrid bus, taking into account the regenerative braking, is comparable with that of a conventional diesel bus. Life-cycle costs are slightly higher because of the added weight and cost of the battery.

Concept and design of a fiber-optic and an I2C hybrid sensor bus system for telecommunication satellites

NASA Astrophysics Data System (ADS)

Putzer, P.; Hurni, A.; Manhart, M.; Tiefenbeck, C.; Plattner, M.; Koch, A. W.

2012-04-01

In this paper the concept and design of the Hybrid Sensor Bus (HSB) system for telecommunication satellites is presented. The HSB development in the frame of an ESA-ARTES project has been started in 2011 and the system will be tested as flight demonstrator onboard the German Heinrich Hertz communication satellite (H2Sat) in 2016. In state-of-the-art telecommunication platforms hundreds of sensors are necessary for satellite control and monitoring. The sensors are wired point-to-point (p2p) to the satellite management unit (SMU) which results in a high mass impact but preliminary increases AIT effort and thereby the overall satellite costs. Sensor bus architectures reduce AIT cost by reduction of wiring effort, reduction in required test time and by providing a flexible sensor network topology. The HSB system is based on a modular concept including a controller module, a fiber-optic interrogator module and an I²C electric interrogator module The HSB system provides advanced performance which includes programmable and sensor specific alarm functions, averaging of dedicated sensor values and thereby a reduction of SMU processor load. The combination of electrical I2C sensors for punctual resolved measurements and fiber-optic sensors for e.g. thermal mapping of panels by embedding sensor fibers in the satellite structures results in a versatile system. In this paper we present the design of the HSB system taking into account the requirements from European platform manufacturers. The HSB design yields a product which can be implemented as replacement of standard p2p systems to build up a more cost efficient sensor system for geostationary satellites.

Analyzing Pulse-Code Modulation On A Small Computer

NASA Technical Reports Server (NTRS)

Massey, David E.

1988-01-01

System for analysis pulse-code modulation (PCM) comprises personal computer, computer program, and peripheral interface adapter on circuit board that plugs into expansion bus of computer. Functions essentially as "snapshot" PCM decommutator, which accepts and stores thousands of frames of PCM data, sifts through them repeatedly to process according to routines specified by operator. Enables faster testing and involves less equipment than older testing systems.

Development of a School Bus Fuel System Integrity Compliance Procedure. Final Report.

ERIC Educational Resources Information Center

Morrow, G. W.; Johnson, N. B.

This report presents a program that derived a compliance test procedure for school buses with a gross vehicle weight of 10,000 pounds or greater. The objective of this program was to evaluate Fuel System Integrity (FMVSS 301) in relation to school buses, conduct a limited state-of-the-art survey and run full-scale dynamic tests to produce an…

Combined Simulated Annealing and Genetic Algorithm Approach to Bus Network Design

NASA Astrophysics Data System (ADS)

Liu, Li; Olszewski, Piotr; Goh, Pong-Chai

A new method - combined simulated annealing (SA) and genetic algorithm (GA) approach is proposed to solve the problem of bus route design and frequency setting for a given road network with fixed bus stop locations and fixed travel demand. The method involves two steps: a set of candidate routes is generated first and then the best subset of these routes is selected by the combined SA and GA procedure. SA is the main process to search for a better solution to minimize the total system cost, comprising user and operator costs. GA is used as a sub-process to generate new solutions. Bus demand assignment on two alternative paths is performed at the solution evaluation stage. The method was implemented on four theoretical grid networks of different size and a benchmark network. Several GA operators (crossover and mutation) were utilized and tested for their effectiveness. The results show that the proposed method can efficiently converge to the optimal solution on a small network but computation time increases significantly with network size. The method can also be used for other transport operation management problems.

Methods for Trustworthy Design of On-Chip Bus Interconnect for General-Purpose Processors

DTIC Science & Technology

2012-03-01

Technology Andrew Huang, was able to test the security properties of HyperTransport bus protocol on an Xbox [20]. In his research, he was able to...TRUSTWORTHY DESIGN OF ON -CHIP BUS INTERCONNECT FOR GENERAL-PURPOSE PROCESSORS by Jay F. Elson March 2012 Thesis Advisor: Ted Huffmire Second...AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Methods for Trustworthy Design of On -Chip Bus Interconnect for General-Purpose Processors 5

49 CFR 383.73 - State procedures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... endorsement knowledge tests; (iv) Allow only a group-specific passenger (P) and school bus (S) endorsement and... must verify the name, date of birth, and Social Security Number provided by the applicant with the...-domiciled CDL. (n) Computer system controls. The State must establish computer system controls that will: (1...

Voltage Analysis Improvement of 150 kV Transmission Subsystem Using Static Synchronous Compensator (STATCOM)

NASA Astrophysics Data System (ADS)

Akbar, P. A.; Hakim, D. L.; Sucita, T.

2018-02-01

In this research, testing improvements to the distribution voltage electricity at 150 kV transmission subsystem Bandung Selatan and New Ujungberung using Flexible AC Transmission System (FACTS) technology. One of them is by doing the control of active and reactive power through the power electronics equipment Static Synchronous Compensator (STATCOM). The subsystem is tested because it has a voltage profile are relatively less well when based on the IEEE / ANSI C.84.1 (142.5 - 157.5 kV). This study was conducted by analyzing the Newton-Raphson power flow on the simulator DigSilent Power Factory 15 to determine the profile of the voltage (V) on the system. Bus which has the lowest voltage to be a reference in the installation of STATCOM. From this research is known that the voltage on the conditions of the existing bus 28, as many as 21-23 still below standard buses (142.5 kV), after the installation is done using STATCOM, voltage on the buses improved by increasing the number of tracks that follow the standard / is in the range 142.5 kV -157.5 kV as many as 23-27 buses or 78.6% - 96%, with the optimum mounting on a bus Rancaekek STATCOM II with a capacity of 300 MVA.

Cathode power distribution system and method of using the same for power distribution

DOEpatents

Williamson, Mark A; Wiedmeyer, Stanley G; Koehl, Eugene R; Bailey, James L; Willit, James L; Barnes, Laurel A; Blaskovitz, Robert J

2014-11-11

Embodiments include a cathode power distribution system and/or method of using the same for power distribution. The cathode power distribution system includes a plurality of cathode assemblies. Each cathode assembly of the plurality of cathode assemblies includes a plurality of cathode rods. The system also includes a plurality of bus bars configured to distribute current to each of the plurality of cathode assemblies. The plurality of bus bars include a first bus bar configured to distribute the current to first ends of the plurality of cathode assemblies and a second bus bar configured to distribute the current to second ends of the plurality of cathode assemblies.

Modular sensor network node

DOEpatents

Davis, Jesse Harper Zehring [Berkeley, CA; Stark, Jr., Douglas Paul; Kershaw, Christopher Patrick [Hayward, CA; Kyker, Ronald Dean [Livermore, CA

2008-06-10

A distributed wireless sensor network node is disclosed. The wireless sensor network node includes a plurality of sensor modules coupled to a system bus and configured to sense a parameter. The parameter may be an object, an event or any other parameter. The node collects data representative of the parameter. The node also includes a communication module coupled to the system bus and configured to allow the node to communicate with other nodes. The node also includes a processing module coupled to the system bus and adapted to receive the data from the sensor module and operable to analyze the data. The node also includes a power module connected to the system bus and operable to generate a regulated voltage.

Research and design of intelligent distributed traffic signal light control system based on CAN bus

NASA Astrophysics Data System (ADS)

Chen, Yu

2007-12-01

Intelligent distributed traffic signal light control system was designed based on technologies of infrared, CAN bus, single chip microprocessor (SCM), etc. The traffic flow signal is processed with the core of SCM AT89C51. At the same time, the SCM controls the CAN bus controller SJA1000/transceiver PCA82C250 to build a CAN bus communication system to transmit data. Moreover, up PC realizes to connect and communicate with SCM through USBCAN chip PDIUSBD12. The distributed traffic signal light control system with three control styles of Vehicle flux, remote and PC is designed. This paper introduces the system composition method and parts of hardware/software design in detail.

Dynamic State Estimation for Multi-Machine Power System by Unscented Kalman Filter With Enhanced Numerical Stability

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

Qi, Junjian; Sun, Kai; Wang, Jianhui

In this paper, in order to enhance the numerical stability of the unscented Kalman filter (UKF) used for power system dynamic state estimation, a new UKF with guaranteed positive semidifinite estimation error covariance (UKFGPS) is proposed and compared with five existing approaches, including UKFschol, UKF-kappa, UKFmodified, UKF-Delta Q, and the squareroot UKF (SRUKF). These methods and the extended Kalman filter (EKF) are tested by performing dynamic state estimation on WSCC 3-machine 9-bus system and NPCC 48-machine 140-bus system. For WSCC system, all methods obtain good estimates. However, for NPCC system, both EKF and the classic UKF fail. It is foundmore » that UKFschol, UKF-kappa, and UKF-Delta Q do not work well in some estimations while UKFGPS works well in most cases. UKFmodified and SRUKF can always work well, indicating their better scalability mainly due to the enhanced numerical stability.« less

Method and systems for a radiation tolerant bus interface circuit

NASA Technical Reports Server (NTRS)

Kinstler, Gary A. (Inventor)

2007-01-01

A bus management tool that allows communication to be maintained between a group of nodes operatively connected on two busses in the presence of radiation by transmitting periodically a first message from one to another of the nodes on one of the busses, determining whether the first message was received by the other of the nodes on the first bus, and when it is determined that the first message was not received by the other of the nodes, transmitting a recovery command to the other of the nodes on a second of the of busses. Methods, systems, and articles of manufacture consistent with the present invention also provide for a bus recovery tool on the other node that re-initializes a bus interface circuit operatively connecting the other node to the first bus in response to the recovery command.

Method and system for pipeline communication

DOEpatents

Richardson,; John, G [Idaho Falls, ID

2008-01-29

A pipeline communication system and method includes a pipeline having a surface extending along at least a portion of the length of the pipeline. A conductive bus is formed to and extends along a portion of the surface of the pipeline. The conductive bus includes a first conductive trace and a second conductive trace with the first and second conductive traces being adapted to conformally couple with a pipeline at the surface extending along at least a portion of the length of the pipeline. A transmitter for sending information along the conductive bus on the pipeline is coupled thereto and a receiver for receiving the information from the conductive bus on the pipeline is also couple to the conductive bus.

High speed bus technology development

NASA Astrophysics Data System (ADS)

Modrow, Marlan B.; Hatfield, Donald W.

1989-09-01

The development and demonstration of the High Speed Data Bus system, a 50 Million bits per second (Mbps) local data network intended for avionics applications in advanced military aircraft is described. The Advanced System Avionics (ASA)/PAVE PILLAR program provided the avionics architecture concept and basic requirements. Designs for wire and fiber optic media were produced and hardware demonstrations were performed. An efficient, robust token-passing protocol was developed and partially demonstrated. The requirements specifications, the trade-offs made, and the resulting designs for both a coaxial wire media system and a fiber optics design are examined. Also, the development of a message-oriented media access protocol is described, from requirements definition through analysis, simulation and experimentation. Finally, the testing and demonstrations conducted on the breadboard and brassboard hardware is presented.

SunLine Transit Agency Advanced Technology Fuel Cell Bus Evaluation: Fourth Results Report

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

Eudy, L.; Chandler, K.

2013-01-01

SunLine Transit Agency, which provides public transit services to the Coachella Valley area of California, has demonstrated hydrogen and fuel cell bus technologies for more than 10 years. In May 2010, SunLine began demonstrating the advanced technology (AT) fuel cell bus with a hybrid electric propulsion system, fuel cell power system, and lithium-based hybrid batteries. This report describes operations at SunLine for the AT fuel cell bus and five compressed natural gas buses. The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is working with SunLine to evaluate the bus in real-world service to document the results and helpmore » determine the progress toward technology readiness. NREL has previously published three reports documenting the operation of the fuel cell bus in service. This report provides a summary of the results with a focus on the bus operation from February 2012 through November 2012.« less

Application of PSAT to Load Flow Analysis with STATCOM under Load Increase Scenario and Line Contingencies

NASA Astrophysics Data System (ADS)

Telang, Aparna S.; Bedekar, P. P.

2017-09-01

Load flow analysis is the initial and essential step for any power system computation. It is required for choosing better options for power system expansion to meet with ever increasing load demand. Implementation of Flexible AC Transmission System (FACTS) device like STATCOM, in the load flow, which is having fast and very flexible control, is one of the important tasks for power system researchers. This paper presents a simple and systematic approach for steady state power flow calculations with FACTS controller, static synchronous compensator (STATCOM) using command line usage of MATLAB tool-power system analysis toolbox (PSAT). The complexity of MATLAB language programming increases due to incorporation of STATCOM in an existing Newton-Raphson load flow algorithm. Thus, the main contribution of this paper is to show how command line usage of user friendly MATLAB tool, PSAT, can extensively be used for quicker and wider interpretation of the results of load flow with STATCOM. The novelty of this paper lies in the method of applying the load increase pattern, where the active and reactive loads have been changed simultaneously at all the load buses under consideration for creating stressed conditions for load flow analysis with STATCOM. The performance have been evaluated on many standard IEEE test systems and the results for standard IEEE-30 bus system, IEEE-57 bus system, and IEEE-118 bus system are presented.

What's Happening on the School Bus Performance Front?

ERIC Educational Resources Information Center

Combs, Hanford L.

The most urgent order of business in the national scene is to complete the development of a series of new performance tests for school bus bodies and chassis to establish a benchmark for safe construction that can be verified by independent testing agencies. Such performance tests should incorporate the new Federal Joint Strength Efficiency…

Cluster Inter-Spacecraft Communications

NASA Technical Reports Server (NTRS)

Cox, Brian

2008-01-01

A document describes a radio communication system being developed for exchanging data and sharing data-processing capabilities among spacecraft flying in formation. The system would establish a high-speed, low-latency, deterministic loop communication path connecting all the spacecraft in a cluster. The system would be a wireless version of a ring bus that complies with the Institute of Electrical and Electronics Engineers (IEEE) standard 1393 (which pertains to a spaceborne fiber-optic data bus enhancement to the IEEE standard developed at NASA's Jet Propulsion Laboratory). Every spacecraft in the cluster would be equipped with a ring-bus radio transceiver. The identity of a spacecraft would be established upon connection into the ring bus, and the spacecraft could be at any location in the ring communication sequence. In the event of failure of a spacecraft, the ring bus would reconfigure itself, bypassing a failed spacecraft. Similarly, the ring bus would reconfigure itself to accommodate a spacecraft newly added to the cluster or newly enabled or re-enabled. Thus, the ring bus would be scalable and robust. Reliability could be increased by launching, into the cluster, spare spacecraft to be activated in the event of failure of other spacecraft.

Evaluation of alternate bus routing project : Phase I

DOT National Transportation Integrated Search

1998-06-01

The official testing of the Alternate Bus Routing (ABR) Project on Garden State Parkway (GSP) commenced on November 17, 1997, by an evaluation team from Rutgers University. Testing lasted for a period of four weeks up to December 12, 1997. This repor...

The EOS Aqua/Aura Experience: Lessons Learned on Design, Integration, and Test of Earth-Observing Satellites

NASA Technical Reports Server (NTRS)

Nosek, Thomas P.

2004-01-01

NASA and NOAA earth observing satellite programs are flying a number of sophisticated scientific instruments which collect data on many phenomena and parameters of the earth's environment. The NASA Earth Observing System (EOS) Program originated the EOS Common Bus approach, which featured two spacecraft (Aqua and Aura) of virtually identical design but with completely different instruments. Significant savings were obtained by the Common Bus approach and these lessons learned are presented as information for future program requiring multiple busses for new diversified instruments with increased capabilities for acquiring earth environmental data volume, accuracy, and type.

The Minerva Multi-Microprocessor.

DTIC Science & Technology

A multiprocessor system is described which is an experiment in low cost, extensible, multiprocessor architectures. Global issues such as inclusion of a central bus, design of the bus arbiter, and methods of interrupt handling are considered. The system initially includes two processor types, based on microprocessors, and these are discussed. Methods for reducing processor demand for the central bus are described.

Unregulated emissions from compressed natural gas (CNG) transit buses configured with and without oxidation catalyst.

PubMed

Okamoto, Robert A; Kado, Norman Y; Kuzmicky, Paul A; Ayala, Alberto; Kobayashi, Reiko

2006-01-01

The unregulated emissions from two in-use heavy-duty transit buses fueled by compressed natural gas (CNG) and equipped with oxidation catalyst (OxiCat) control were evaluated. We tested emissions from a transit bus powered by a 2001 Cummins Westport C Gas Plus 8.3-L engine (CWest), which meets the California Air Resources Board's (CARB) 2002 optional NOx standard (2.0 g/bhp-hr). In California, this engine is certified only with an OxiCat, so our study did not include emissions testing without it. We also tested a 2000 New Flyer 40-passenger low-floor bus powered by a Detroit Diesel series 50G engine (DDCs50G) that is currently certified in California without an OxiCat. The original equipment manufacturer (OEM) offers a "low-emission" package for this bus that includes an OxiCat for transit bus applications, thus, this configuration was also tested in this study. Previously, we reported that formaldehyde and other volatile organic emissions detected in the exhaust of the DDCs50G bus equipped with an OxiCat were significantly reduced relative to the same DDCs50G bus without OxiCat. In this paper, we examine othertoxic unregulated emissions of significance. The specific mutagenic activity of emission sample extracts was examined using the microsuspension assay. The total mutagenic activity of emissions (activity per mile) from the OxiCat-equipped DDC bus was generally lower than that from the DDC bus without the OxiCat. The CWest bus emission samples had mutagenic activity that was comparable to that of the OxiCat-equipped DDC bus. In general, polycyclic aromatic hydrocarbon (PAH) emissions were lower forthe OxiCat-equipped buses, with greater reductions observed for the volatile and semivolatile PAH emissions. Elemental carbon (EC) was detected in the exhaust from the all three bus configurations, and we found that the total carbon (TC) composition of particulate matter (PM) emissions was primarily organic carbon (OC). The amount of carbon emissions far exceeded the PM-associated inorganic element emissions, which were detected in all exhaust samples, at comparatively small emission rates. In summary, based on these results and those referenced from our group, the use of OxiCat for the new CWest engine and as a retrofit option for the DDCs50G engine generally results in the reduction of tailpipe toxic emissions. However, the conclusions of this study do not take into account OxiCat durability, deterioration, lubricant consumption, or vehicle maintenance, and these parameters merit further study.

Bus-Programmable Slave Card

NASA Technical Reports Server (NTRS)

Hall, William A.

1990-01-01

Slave microprocessors in multimicroprocessor computing system contains modified circuit cards programmed via bus connecting master processor with slave microprocessors. Enables interactive, microprocessor-based, single-loop control. Confers ability to load and run program from master/slave bus, without need for microprocessor development station. Tristate buffers latch all data and information on status. Slave central processing unit never connected directly to bus.

Survey of transit bus maintenance programs in Virginia.

DOT National Transportation Integrated Search

1981-01-01

Transit bus maintenance practices as used by thirteen small and medium-sized transit systems in Virginia were cataloged. Different approaches to maintenance were investigated and the current condition of transit bus maintenance was determined. Factor...

TET-1- A German Microsatellite for Technology On -Orbit Verification

NASA Astrophysics Data System (ADS)

Föckersperger, S.; Lattner, K.; Kaiser, C.; Eckert, S.; Bärwald, W.; Ritzmann, S.; Mühlbauer, P.; Turk, M.; Willemsen, P.

2008-08-01

Due to the high safety standards in the space industry every new product must go through a verification process before qualifying for operation in a space system. Within the verification process the payload undergoes a series of tests which prove that it is in accordance with mission requirements in terms of function, reliability and safety. Important verification components are the qualification for use on the ground as well as the On-Orbit Verification (OOV), i.e. proof that the product is suitable for use under virtual space conditions (on-orbit). Here it is demonstrated that the product functions under conditions which cannot or can only be partially simulated on the ground. The OOV-Program of the DLR serves to bridge the gap between the product tested and qualified on the ground and the utilization of the product in space. Due to regular and short-term availability of flight opportunities industry and research facilities can verify their latest products under space conditions and demonstrate their reliability and marketability. The Technologie-Erprobungs-Tr&äger TET (Technology Experiments Carrier) comprises the core elements of the OOV Program. A programmatic requirement of the OOV Program is that a satellite bus already verified in orbit be used in the first segment of the program. An analysis of suitable satellite buses showed that a realization of the TET satellite bus based on the BIRD satellite bus fulfilled the programmatic requirements best. Kayser-Threde was selected by DLR as Prime Contractor to perform the project together with its major subcontractors Astro- und Feinwerktechnik, Berlin for the platform development and DLR-GSOC for the ground segment development. TET is now designed to be a modular and flexible micro-satellite for any orbit between 450 and 850 km altitude and inclination between 53° and SSO. With an overall mass of 120 kg TET is able to accommodate experiments of up to 50 kg. A multipurpose payload supply systemThere is significant confusion in the space industry today over the terms used to describe satellite bus architectures. Terms such as "standard bus" (or "common bus"), "modular bus" and "plug-and-play bus" are often used with little understanding of what the terms actually mean, and even less understanding of what the differences in these space architectures mean. It may seem that these terms are subtle differentiators, but in reality these terms describe radically different ways to design, build, test, and operate satellites. Furthermore, these terms imply very different business models for the acquisition, operation, and sustainment of space systems. This paper will define and describe the difference between "standard buses", "modular buses" and "plug-and-play buses"; giving examples of each kind with a cost/benefit discussion of each type. under Kayser-Threde responsibility provides the necessary interfaces to the experiments. The first TET mission is scheduled for mid of 2010. TET will be launched as piggy-back payload on any available launcher worldwide to reduce launch cost and provide maximum flexibility. Finally, TET will provide all services required by the experimenters for a one year mission operation to perform a successful OOV-mission with its technology experiments leading to an efficient access to space for German industry and institutions.

Combined comfort model of thermal comfort and air quality on buses in Hong Kong.

PubMed

Shek, Ka Wing; Chan, Wai Tin

2008-01-25

Air-conditioning settings are important factors in controlling the comfort of passengers on buses. The local bus operators control in-bus air quality and thermal environment by conforming to the prescribed levels stated in published standards. As a result, the settings are merely adjusted to fulfill the standards, rather than to satisfy the passengers' thermal comfort and air quality. Such "standard-oriented" practices are not appropriate; the passengers' preferences and satisfaction should be emphasized instead. Thus a "comfort-oriented" philosophy should be implemented to achieve a comfortable in-bus commuting environment. In this study, the achievement of a comfortable in-bus environment was examined with emphasis on thermal comfort and air quality. Both the measurement of physical parameters and subjective questionnaire surveys were conducted to collect practical in-bus thermal and air parameters data, as well as subjective satisfaction and sensation votes from the passengers. By analyzing the correlation between the objective and subjective data, a combined comfort models were developed. The models helped in evaluating the percentage of dissatisfaction under various combinations of passengers' sensation votes towards thermal comfort and air quality. An effective approach integrated the combined comfort model, hardware and software systems and the bus air-conditioning system could effectively control the transient in-bus environment. By processing and analyzing the data from the continuous monitoring system with the combined comfort model, air-conditioning setting adjustment commands could be determined and delivered to the hardware. This system adjusted air-conditioning settings depending on real-time commands along the bus journey. Therefore, a comfortable in-bus air quality and thermal environment could be achieved and efficiently maintained along the bus journey despite dynamic outdoor influences. Moreover, this model can help optimize air-conditioning control by striking a beneficial balance between energy conservation and passengers' satisfaction level.

Advanced Stirling Convertor Dual Convertor Controller Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

NASA Technical Reports Server (NTRS)

Dugala, Gina M.; Taylor, Linda M.; Bell, Mark E.; Dolce, James L.; Fraeman, Martin; Frankford, David P.

2015-01-01

NASA Glenn Research Center developed a nonnuclear representation of a Radioisotope Power System (RPS) consisting of a pair of Advanced Stirling Convertors (ASCs), Dual Convertor Controller (DCC) EMs (engineering models) 2 and 3, and associated support equipment, which were tested in the Radioisotope Power Systems System Integration Laboratory (RSIL). The DCC was designed by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) to actively control a pair of ASCs. The first phase of testing included a Dual Advanced Stirling Convertor Simulator (DASCS), which was developed by JHU/APL and simulates the operation and electrical behavior of a pair of ASCs in real time via a combination of hardware and software. RSIL provides insight into the electrical interactions between a representative radioisotope power generator, its associated control schemes, and realistic electric system loads. The first phase of integration testing included the following spacecraft bus configurations: capacitive, battery, and super-capacitor. A load profile, created based on data from several missions, tested the RPS's and RSIL's ability to maintain operation during load demands above and below the power provided by the RPS. The integration testing also confirmed the DCC's ability to disconnect from the spacecraft when the bus voltage dipped below 22 volts or exceeded 36 volts. Once operation was verified with the DASCS, the tests were repeated with actual operating ASCs. The goal of this integration testing was to verify operation of the DCC when connected to a spacecraft and to verify the functionality of the newly designed RSIL. The results of these tests are presented in this paper.

Test-bench system for a borehole azimuthal acoustic reflection imaging logging tool

NASA Astrophysics Data System (ADS)

Liu, Xianping; Ju, Xiaodong; Qiao, Wenxiao; Lu, Junqiang; Men, Baiyong; Liu, Dong

2016-06-01

The borehole azimuthal acoustic reflection imaging logging tool (BAAR) is a new generation of imaging logging tool, which is able to investigate stratums in a relatively larger range of space around the borehole. The BAAR is designed based on the idea of modularization with a very complex structure, so it has become urgent for us to develop a dedicated test-bench system to debug each module of the BAAR. With the help of a test-bench system introduced in this paper, test and calibration of BAAR can be easily achieved. The test-bench system is designed based on the client/server model. The hardware system mainly consists of a host computer, an embedded controlling board, a bus interface board, a data acquisition board and a telemetry communication board. The host computer serves as the human machine interface and processes the uploaded data. The software running on the host computer is designed based on VC++. The embedded controlling board uses Advanced Reduced Instruction Set Machines 7 (ARM7) as the micro controller and communicates with the host computer via Ethernet. The software for the embedded controlling board is developed based on the operating system uClinux. The bus interface board, data acquisition board and telemetry communication board are designed based on a field programmable gate array (FPGA) and provide test interfaces for the logging tool. To examine the feasibility of the test-bench system, it was set up to perform a test on BAAR. By analyzing the test results, an unqualified channel of the electronic receiving cabin was discovered. It is suggested that the test-bench system can be used to quickly determine the working condition of sub modules of BAAR and it is of great significance in improving production efficiency and accelerating industrial production of the logging tool.

Design and development of an automatic data acquisition system for a balance study using a smartcard system.

PubMed

Ambrozy, C; Kolar, N A; Rattay, F

2010-01-01

For measurement value logging of board angle values during balance training, it is necessary to develop a measurement system. This study will provide data for a balance study using the smartcard. The data acquisition comes automatically. An individually training plan for each proband is necessary. To store the proband identification a smartcard with an I2C data bus protocol and an E2PROM memory system is used. For reading the smartcard data a smartcard reader is connected via universal serial bus (USB) to a notebook. The data acquisition and smartcard read programme is designed with Microsoft® Visual C#. A training plan file contains the individual training plan for each proband. The data of the test persons are saved in a proband directory. Each event is automatically saved as a log-file for the exact documentation. This system makes study development easy and time-saving.

Simulation of an Urban Battery Bus Vehicle

DOT National Transportation Integrated Search

1979-07-01

This report describes the computer simulation of a battery-powered bus as it traverses an arbitrary mission profile of specified acceleration, roadway grade, and headwind. The battery-bus system components comprise a DC shunt motor, solid-state power...

Methods of computing steady-state voltage stability margins of power systems

DOEpatents

Chow, Joe Hong; Ghiocel, Scott Gordon

2018-03-20

In steady-state voltage stability analysis, as load increases toward a maximum, conventional Newton-Raphson power flow Jacobian matrix becomes increasingly ill-conditioned so power flow fails to converge before reaching maximum loading. A method to directly eliminate this singularity reformulates the power flow problem by introducing an AQ bus with specified bus angle and reactive power consumption of a load bus. For steady-state voltage stability analysis, the angle separation between the swing bus and AQ bus can be varied to control power transfer to the load, rather than specifying the load power itself. For an AQ bus, the power flow formulation is only made up of a reactive power equation, thus reducing the size of the Jacobian matrix by one. This reduced Jacobian matrix is nonsingular at the critical voltage point, eliminating a major difficulty in voltage stability analysis for power system operations.

Systems evaluation of thermal bus concepts

NASA Technical Reports Server (NTRS)

Stalmach, D. D.

1982-01-01

Thermal bus concepts, to provide a centralized thermal utility for large, multihundred kilowatt space platforms, were studied and the results are summarized. Concepts were generated, defined, and screened for inclusion in system level thermal bus trades. Parametric trade studies were conducted in order to define the operational envelope, performance, and physical characteristics of each. Two concepts were selected as offering the most promise for thermal bus development. All of four concepts involved two phase flow in order to meet the required isothermal nature of the thermal bus. Two of the concepts employ a mechanical means to circulate the working fluid, a liquid pump in one case and a vapor compressor in another. Another concept utilizes direct osmosis as the driving force of the thermal bus. The fourth concept was a high capacity monogroove heat pipe. After preliminary sizing and screening, three of these concepts were selected to carry into the trade studies. The monogroove heat pipe concept was deemed unsuitable for further consideration because of its heat transport limitations. One additional concept utilizing capillary forces to drive the working fluid was added. Parametric system level trade studies were performed. Sizing and weight calculations were performed for thermal bus sizes ranging from 5 to 350 kW and operating temperatures in the range of 4 to 120 C. System level considerations such as heat rejection and electrical power penalties and interface temperature losses were included in the weight calculations.

Evaluating a GPS-Based Transportation Device to Support Independent Bus Travel by People with Intellectual Disability

ERIC Educational Resources Information Center

Davies, Daniel K.; Stock, Steven E.; Holloway, Shane; Wehmeyer, Michael L.

2010-01-01

We examined the utility of a PDA-based software system with integrated GPS technology for providing location-aware visual and auditory prompts to enable people with intellectual disability to successfully navigate a downtown bus route. Participants using the system were significantly more successful at completing a bus route than were people in a…

Spacecraft System Integration and Test: SSTI Lewis critical design audit

NASA Technical Reports Server (NTRS)

Brooks, R. P.; Cha, K. K.

1995-01-01

The Critical Design Audit package is the final detailed design package which provides a comprehensive description of the SSTI mission. This package includes the program overview, the system requirements, the science and applications activities, the ground segment development, the assembly, integration and test description, the payload and technology demonstrations, and the spacecraft bus subsystems. Publication and presentation of this document marks the final requirements and design freeze for SSTI.

Concept Study on a Flexible Standard Bus for Small Scientific Satellites

NASA Astrophysics Data System (ADS)

Fukuda, Seisuke; Sawai, Shujiro; Sakai, Shin-Ichiro; Saito, Hirobumi; Tohma, Takayuki; Takahashi, Junko; Toriumi, Tsuyoshi; Kitade, Kenji

In this paper, a new standard bus system for a series of small scientific satellites in the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA) is described. Since each mission proposed for the series has a wide variety of requirements, a lot of efforts are needed to enhance flexibility of the standard bus. Some concepts from different viewpoints are proposed. First, standardization layers concerning satellite configuration, instruments, interfaces, and design methods are defined respectively. Methods of product platform engineering, which classify specifications of the bus system into a core platform, alternative variants, and selectable variants, are also investigated in order to realize a semi-custom-made bus. Furthermore, a tradeoff between integration and modularization architecture is fully considered.

Study of the impact of automation on productivity in bus-maintenance facilities. Final report

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

Sumanth, D.J.; Weiss, H.J.; Adya, B.

1988-12-01

Whether or not the various types of automation and new technologies introduced in a bus-transit system really have an impact on productivity is the question addressed in the study. The report describes a new procedure of productivity measurement and evaluation for a county-transit system and provides an objective perspective on the impact of automation on productivity in bus maintenance facilities. The research objectives were: to study the impact of automation on total productivity in transit maintenance facilities; to develop and apply a methodology for measuring the total productivity of a Floridian transit maintenance facility (Bradenton-Manatee County bus maintenance facility whichmore » has been introducing automation since 1983); and to develop a practical step-by-step implementation scheme for the total productivity-based productivity measurement system that any bus manager can use. All 3 objectives were successfully accomplished.« less

Study on emission characteristics of hybrid bus under driving cycles in typical Chinese city

NASA Astrophysics Data System (ADS)

Xie, Yongdong; Xu, Guangju

2017-09-01

In this study, hybrid city bus was taken as the research object, through the vehicle drum test, the vehicle emissions of hybrid bus, the transient emissions of gas pollutants, as well as the particle size and number distribution were surveyed. The results of the studies are listed as follows: First, compared to traditional fuel bus, hybrid bus could reduce about 44% of the NOx emissions, 33% of the total hydrocarbon emissions, and 51% of the particles emissions. Furthermore, the distribution of particles number concentration of test vehicle became high in middle and low in both sides. More specifically, the particle number concentration was mainly concentrated in the range from 0.021 to 0.755μm, the maximum was 0.2μm, and particle size of particulate matter (PM) less than 1.2μm accounted for 95% of the total number concentration. Particulate mass concentration was increased with increment of particle size, and the maximum of particulate mass (PM) concentration was 6.2μm. On average, whether traditional fuel bus or hybrid bus, the particle size of particulate matter(PM) less than 2.5μm accounted for more than 98% in the particles emission. It is found that the particles are more likely to deposit to the lung, respiratory bronchioles and alveoli, causing respiratory and lung diseases. Therefore, how to control the PM emissions of hybrid bus is the key factor of the study.

The universal serial bus endoscope: design and initial clinical experience.

PubMed

Hernandez-Zendejas, Gregorio; Dobke, Marek K; Guerrerosantos, Jose

2004-01-01

Endoscopic forehead lift is a well-established procedure in aesthetic plastic surgery. Many agree that currently available video-endoscopic equipment is bulky, multipieced and sometimes cumbersome in the operating theater. A novel system, the Universal Serial Bus Endoscope (USBE) was designed to simplify and reduce the number of necessary equipment pieces in the endoscopic setup. The USBE is attached by a single cable to a Universal Serial Bus (USB) port of a laptop computer. A built-in miniaturized cold light source provides illumination. A built-in digital camera chip enables procedure recording. The real-time images and movies obtained with USBE are displayed on the computer's screen and recorded on the laptop's hard disk drive. In this study, 25 patients underwent endoscopic browlift using the USBE system to test its clinical usefulness, all with good results and without complications or need for revision. The USBE was found to be reliable and easier to use than current video-endoscope equipment. The operative time needed to complete the procedure by the authors was reduced approximately 50%. The design and main technical characteristics of the USBE are presented.

Interfacing external sensors with Android smartphones through near field communication

NASA Astrophysics Data System (ADS)

Leikanger, Tore; Häkkinen, Juha; Schuss, Christian

2017-04-01

In this paper, we present and evaluate a new approach to communicate with inter-integrated circuit (I2C) enabled circuits such as sensors over near field communication (NFC). The NFC-to-I2C interface was designed using a non-standard NFC command to control the I2C bus directly from a smartphone, which was controlling both, the read and write operations on the I2C bus. The NFC-to-I2C interface was reporting back the data bytes on the bus to the smartphone when the transaction was completed successfully. The proposed system was tested experimentally, both, with write and read requests to a commercial microcontroller featuring a hardware I2C port, as well as reading a commercial I2C enabled humidity and temperature sensor. We present experimental results of the system which show that our approach enables an easy interface between smartphones and external sensors. Interfacing external sensors is useful and beneficial for smartphone users, especially, if certain types of sensors are not available on smartphones.

Performance evaluation of Platform Data ManagementSystem under various degrees of protocol implementation

NASA Technical Reports Server (NTRS)

Arozullah, Mohammed

1991-01-01

The Platform Data Management System (DMS) collects Housekeeping (H/K), Payload (P/L) Engineering, and Payload Science data from various subsystems and payloads on the platform for transmission to the ground through the downlink via TDRSS. The DMS also distributes command data received from the ground to various subsystems and payloads. In addition, DMS distributes timing and safemode data. The function of collection and distribution of various types of data is performed by the Command and Data Handling (C&DH) subsystem of DMS. The C&DH subsystem uses for this purpose a number of data buses namely, Housekeeping, Payload Engineering, Payload Science, and Time and Safemode buses. Out of these buses, the H/K, P/L Engineering, and P/L Science buses are planned to be implemented by using MIL-STD 1553 bus. Most of the period covered was spent in developing a queue theoretic model of the 1553 Bus as used in the DMS. The aim is to use this model to test the performance and suitability of the 1553 Bus to the DMS under a number of alternative design scenarios.

Mass transit : bus rapid transit shows promise

DOT National Transportation Integrated Search

2001-09-17

The U. S. General Accounting Office (GAO) was asked to (1) examine the federal role in supporting Bus Rapid Transit; (2) compare the capital costs, operating costs, and performance characteristics of Bus Rapid Transit and Light Rail systems; and (3) ...

49 CFR 383.73 - State procedures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... endorsement knowledge tests; (iv) Allow only a group-specific passenger (P) and school bus (S) endorsement and... verification. (1) Prior to issuing a CLP or a CDL to a person the State must verify the name, date of birth... of issuance of the CLP or CDL. (n) Computer system controls. The State must establish computer system...

49 CFR 383.73 - State procedures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... endorsement knowledge tests; (iv) Allow only a group-specific passenger (P) and school bus (S) endorsement and... verification. (1) Prior to issuing a CLP or a CDL to a person the State must verify the name, date of birth... of issuance of the CLP or CDL. (n) Computer system controls. The State must establish computer system...

Magnet measurement interfacing to the G-64 Euro standard bus and testing G-64 modules

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

Hogrefe, R.L.

1995-07-01

The Magnet Measurement system utilizes various modules with a G-64 Euro (Gespac) Standard Interface. All modules are designed to be software controlled, normally under the constraints of the OS-9 operating system with all data transfers to a host computer accomplished by a serial link.

Advanced flight control system study

NASA Technical Reports Server (NTRS)

Mcgough, J.; Moses, K.; Klafin, J. F.

1982-01-01

The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed.

Power System Test and Verification at Satellite Level

NASA Astrophysics Data System (ADS)

Simonelli, Giulio; Mourra, Olivier; Tonicello, Ferdinando

2008-09-01

Most of the articles on Power Systems deal with the architecture and technical solutions related to the functionalities of the power system and their performances. Very few articles, if none, address integration and verification aspects of the Power System at satellite level and the related issues with the Power EGSE (Electrical Ground Support Equipment), which, also, have to support the AIT/AIV (Assembly Integration Test and Verification) program of the satellite and, eventually, the launch campaign. In the last years a more complex development and testing concept based on MDVE (Model Based Development and Verification Environment) has been introduced. In the MDVE approach the simulation software is used to simulate the Satellite environment and, in the early stages, the satellites units. This approach changed significantly the Power EGSE requirements. Power EGSEs or, better, Power SCOEs (Special Check Out Equipment) are now requested to provide the instantaneous power generated by the solar array throughout the orbit. To achieve that, the Power SCOE interfaces to the RTS (Real Time Simulator) of the MDVE. The RTS provides the instantaneous settings, which belong to that point along the orbit, to the Power SCOE so that the Power SCOE generates the instantaneous {I,V} curve of the SA (Solar Array). That means a real time test for the power system, which is even more valuable for EO (Earth Observation) satellites where the Solar Array aspect angle to the sun is rarely fixed, and the power load profile can be particularly complex (for example, in radar applications). In this article the major issues related to integration and testing of Power Systems will be discussed taking into account different power system topologies (i.e. regulated bus, unregulated bus, battery bus, based on MPPT or S3R…). Also aspects about Power System AIT I/Fs (interfaces) and Umbilical I/Fs with the launcher and the Power SCOE I/Fs will be addressed. Last but not least, protection strategy of the Power System during AIT/AIV program will also be discussed. The objective of this discussion is also to provide the Power System Engineer with a checklist of key aspects linked to the satellite AIT/AIV program, that have to be considered in the early phases of a new power system development.

The In-Orbit Battery Reconditioning Experience On Board the Orion 1 Spacecraft

NASA Technical Reports Server (NTRS)

Hoover, S. A.; Daughtridge, S.; Johnson, P. J.; King, S. T.

1997-01-01

The Orion 1 spacecraft is a three-axis stabilized geostationary earth orbiting commercial communications satellite which was launched on November 29, 1994 aboard an Atlas II launch vehicle. The power subsystem is a dual bus, dual battery semi-regulated system with one 78 Ampere-hour nickel-hydrogen battery per bus. The batteries were built and tested by Eagle Picher Industries, Inc., of Joplin, MO and were integrated into the spacecraft by its manufacturer, Matra Marconi Space UK Ltd. This paper presents the results obtained during the first four in-orbit reconditioning cycles and compares the battery performance to ground test data. In addition, the on-station battery management strategy and implementation constraints are described. Battery performance has been nominal throughout each reconditioning cycle and subsequent eclipse season.

49 CFR 665.25 - Transportation of vehicle.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Transportation of vehicle. 665.25 Section 665.25..., DEPARTMENT OF TRANSPORTATION BUS TESTING Operations § 665.25 Transportation of vehicle. A manufacturer shall be responsible for transporting its vehicle to and from the bus testing facility at the beginning and...

49 CFR 665.25 - Transportation of vehicle.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Transportation of vehicle. 665.25 Section 665.25..., DEPARTMENT OF TRANSPORTATION BUS TESTING Operations § 665.25 Transportation of vehicle. A manufacturer shall be responsible for transporting its vehicle to and from the bus testing facility at the beginning and...

Integration of Fixed and Flexible Route Public Transportation Systems, Phase II

DOT National Transportation Integrated Search

2012-01-01

Conventional bus service (with fixed routes and schedules) has lower average cost than flexible bus service (with : demand-responsive routes) at high demand densities. At low demand densities flexible bus service has lower : average costs and provide...

Intelligent subsystem interface for modular hardware system

NASA Technical Reports Server (NTRS)

Caffrey, Robert T. (Inventor); Krening, Douglas N. (Inventor); Lannan, Gregory B. (Inventor); Schneiderwind, Michael J. (Inventor); Schneiderwind, Robert A. (Inventor)

2000-01-01

A single chip application specific integrated circuit (ASIC) which provides a flexible, modular interface between a subsystem and a standard system bus. The ASIC includes a microcontroller/microprocessor, a serial interface for connection to the bus, and a variety of communications interface devices available for coupling to the subsystem. A three-bus architecture, utilizing arbitration, provides connectivity within the ASIC and between the ASIC and the subsystem. The communication interface devices include UART (serial), parallel, analog, and external device interface utilizing bus connections paired with device select signals. A low power (sleep) mode is provided as is a processor disable option.

Structural Bus and Release Mechanisms on the ST5 Satellites: Summary and Status

NASA Technical Reports Server (NTRS)

Rossoni, Peter

2007-01-01

The Space Technology 5 Mechanical System met the challenge of packaging a fully functional science and technology satellite system with its Deployer mechanism into a compact 0.07cu m volume. Three 25 kg satellites were orbited in constellation in March, 2006. The ST5 mechanical system is composed of 1) The Structural Bus; 2) Magnetometer Instrument Boom 3) Spacecraft Deployer Release Mechanism This system includes a highly integrated electronics enclosure as a multifunctional structure; a lightweight, magnetically clean Magnetometer Boom; the first use of Nitinol Shape-Memory Alloy trigger devices for deploying multiple spacecraft; an innovative compliant mount for the umbilical connector and a Deployer mechanism that imparts both separation velocity and mission spin rate to three constellation flying satellites These elements employed cutting-edge design and analysis tools, state-of-the-art testing facilities and proven engineering techniques to meet stringent performance criteria, enabling the mission s success.

Applying Reduced Generator Models in the Coarse Solver of Parareal in Time Parallel Power System Simulation

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

Duan, Nan; Dimitrovski, Aleksandar D; Simunovic, Srdjan

2016-01-01

The development of high-performance computing techniques and platforms has provided many opportunities for real-time or even faster-than-real-time implementation of power system simulations. One approach uses the Parareal in time framework. The Parareal algorithm has shown promising theoretical simulation speedups by temporal decomposing a simulation run into a coarse simulation on the entire simulation interval and fine simulations on sequential sub-intervals linked through the coarse simulation. However, it has been found that the time cost of the coarse solver needs to be reduced to fully exploit the potentials of the Parareal algorithm. This paper studies a Parareal implementation using reduced generatormore » models for the coarse solver and reports the testing results on the IEEE 39-bus system and a 327-generator 2383-bus Polish system model.« less

Measuring self-pollution in school buses using a tracer gas technique

NASA Astrophysics Data System (ADS)

Behrentz, Eduardo; Fitz, Dennis R.; Pankratz, David V.; Sabin, Lisa D.; Colome, Steven D.; Fruin, Scott A.; Winer, Arthur M.

A potentially important, but inadequately studied, source of children's exposure to pollutants during school bus commutes is the introduction of a bus's own exhaust into the passenger compartment. We developed and applied a method to determine the amount of a bus's own exhaust penetrating into the cabin in a study of six in-use school buses over a range of routes, roadway types, fuels, and emission control technologies. A tracer gas, SF 6, was metered into the bus's exhaust system using a mass flow controller whose flow rate was logged by a data acquisition system and processed with the concurrent real-time pollutant measurement data. At the same time, the SF 6 concentration inside the bus was measured using an AeroVironment CTA-1000 continuous analyzer connected to a series of solenoids that switched the sample inlet between the front and rear of the bus cabin. To account for a baseline drift of the CTA-1000, SF 6-free air was also drawn through a line located outside at the front of the bus. Although this third sample line generally provided a reference zero value, it also showed that under certain wind conditions (i.e., wind from the rear) when the bus was stopped and was idling, significant amounts of the bus's own exhaust reached this location at the front of the bus. Self-pollution, the percentage of a bus's own exhaust that can be found inside its cabin, was a function of bus type and age, and a strong function of window position (i.e., open or closed). We estimated up to 0.3% of the air inside the cabin was from the bus's own exhaust in older buses, approximately 10 times the percentage observed for newer buses, and 25% of the black carbon concentration variance was explained by the buses' self-pollution. Analysis of the tracer gas concentrations provided a powerful tool for identifying potentially high-exposure conditions.

Protective effect of L-carnitine and L-arginine against busulfan-induced oligospermia in adult rat.

PubMed

Abd-Elrazek, A M; Ahmed-Farid, O A H

2018-02-01

Busulfan is an anticancer drug caused variety of adverse effects for patients with cancer. But it could cause damage to the male reproductive system as one of its adverse effects. This study aimed to investigate the protective effect of L-carnitine and L-arginine on semen quality, oxidative stress parameters and testes cell energy after busulfan treatment. Adult male rats were divided into four groups: control (Con), busulfan (Bus), busulfan plus L-arginine (Bus + L-arg) and busulfan plus L-carnitine (Bus + L-car). After 28 days, the semen was collected from the epididymis and the testes were assessed. Sperm count, motility and velocity were measured by CASA, and smears were prepared for assessment of sperm morphology. Serum and testes supernatants were separated for DNA metabolites, oxidative stress and cell energy parameters. Testes tissues also subjected for caspase-3. The results showed significant improvement in sperm morphology, motility, velocity and count in the groups treated with L-arginine and L-carnitine and accompanied with an increase in MDA, GSSG and ATP, reduction in GSH, AMP, ADP, NO and 8-OHDG also recorded. These results are supported by caspase-3. Administration of L-arg and L-car attenuated the cytotoxic effects of busulfan by improving semen parameters, reducing oxidative stress and maintaining cell energy. © 2017 Blackwell Verlag GmbH.

The SMART MIL-STD-1553 bus adapter hardware manual

NASA Technical Reports Server (NTRS)

Ton, T. T.

1981-01-01

The SMART Multiplexer Interface Adapter, (SMIA) a complete system interface for message structure of the MIL-STD-1553, is described. It provides buffering and storage for transmitted and received data and handles all the necessary handshaking to interface between parallel 8-bit data bus and a MIL-STD serial bit stream. The bus adapter is configured as either a bus controller of a remote terminal interface. It is coupled directly to the multiplex bus, or stub coupled through an additional isolation transformer located at the connection point. Fault isolation resistors provide short circuit protection.

Front Range commuter bus study. Phase 2 : final report

DOT National Transportation Integrated Search

2003-10-01

The goal of Front Range Commuter Bus service would be to provide a commuter bus service that would operate seamlessly with local transit systems and would be run through a partnership with each of the cities, CDOT, RTD and participating private provi...

Design of temperature monitoring system based on CAN bus

NASA Astrophysics Data System (ADS)

Zhang, Li

2017-10-01

The remote temperature monitoring system based on the Controller Area Network (CAN) bus is designed to collect the multi-node remote temperature. By using the STM32F103 as main controller and multiple DS18B20s as temperature sensors, the system achieves a master-slave node data acquisition and transmission based on the CAN bus protocol. And making use of the serial port communication technology to communicate with the host computer, the system achieves the function of remote temperature storage, historical data show and the temperature waveform display.

Modular Cooling Components

NASA Technical Reports Server (NTRS)

Eastman, G. Yale; Dussinger, Peter M.; Hartenstine, John R.

1994-01-01

Three modular heat-transfer components designed for use together or separately. Simple mechanical connections facilitate assembly of these and related heat-transfer components into cooling systems of various configurations, such as to cool laboratory equipment rearranged for different experiments. Components are clamp-on cold plate, cold plate attached to flexible heat pipe, and thermal-bus receptacle. Clamp-on cold plate moved to any convenient location for attachment of equipment cooled by it, then clamped onto thermal bus. Heat from equipment conducted through plate and into coolant. Thermal-bus receptacle integral with thermal bus. Includes part of thermal bus to which clamp-on cold plate attached, plus tapered socket into which condenser end of flexible heat pipe plugged. Thermal-bus receptacle includes heat-pipe wick structure using coolant in bus to enhance transfer of heat from cold plate.

System level latchup mitigation for single event and transient radiation effects on electronics

DOEpatents

Kimbrough, J.R.; Colella, N.J.

1997-09-30

A ``blink`` technique, analogous to a person blinking at a flash of bright light, is provided for mitigating the effects of single event current latchup and prompt pulse destructive radiation on a micro-electronic circuit. The system includes event detection circuitry, power dump logic circuitry, and energy limiting measures with autonomous recovery. The event detection circuitry includes ionizing radiation pulse detection means for detecting a pulse of ionizing radiation and for providing at an output terminal thereof a detection signal indicative of the detection of a pulse of ionizing radiation. The current sensing circuitry is coupled to the power bus for determining an occurrence of excess current through the power bus caused by ionizing radiation or by ion-induced destructive latchup of a semiconductor device. The power dump circuitry includes power dump logic circuitry having a first input terminal connected to the output terminal of the ionizing radiation pulse detection circuitry and having a second input terminal connected to the output terminal of the current sensing circuitry. The power dump logic circuitry provides an output signal to the input terminal of the circuitry for opening the power bus and the circuitry for shorting the power bus to a ground potential to remove power from the power bus. The energy limiting circuitry with autonomous recovery includes circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential. The circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential includes a series FET and a shunt FET. The invention provides for self-contained sensing for latchup, first removal of power to protect latched components, and autonomous recovery to enable transparent operation of other system elements. 18 figs.

System level latchup mitigation for single event and transient radiation effects on electronics

DOEpatents

Kimbrough, Joseph Robert; Colella, Nicholas John

1997-01-01

A "blink" technique, analogous to a person blinking at a flash of bright light, is provided for mitigating the effects of single event current latchup and prompt pulse destructive radiation on a micro-electronic circuit. The system includes event detection circuitry, power dump logic circuitry, and energy limiting measures with autonomous recovery. The event detection circuitry includes ionizing radiation pulse detection means for detecting a pulse of ionizing radiation and for providing at an output terminal thereof a detection signal indicative of the detection of a pulse of ionizing radiation. The current sensing circuitry is coupled to the power bus for determining an occurrence of excess current through the power bus caused by ionizing radiation or by ion-induced destructive latchup of a semiconductor device. The power dump circuitry includes power dump logic circuitry having a first input terminal connected to the output terminal of the ionizing radiation pulse detection circuitry and having a second input terminal connected to the output terminal of the current sensing circuitry. The power dump logic circuitry provides an output signal to the input terminal of the circuitry for opening the power bus and the circuitry for shorting the power bus to a ground potential to remove power from the power bus. The energy limiting circuitry with autonomous recovery includes circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential. The circuitry for opening the power bus and circuitry for shorting the power bus to a ground potential includes a series FET and a shunt FET. The invention provides for self-contained sensing for latchup, first removal of power to protect latched components, and autonomous recovery to enable transparent operation of other system elements.

Systems design study of the Pioneer Venus spacecraft. Volume 2. Preliminary program development plan

NASA Technical Reports Server (NTRS)

1973-01-01

The preliminary development plan for the Pioneer Venus program is presented. This preliminary plan treats only developmental aspects that would have a significant effect on program cost. These significant development areas were: master program schedule planning; test planning - both unit and system testing for probes/orbiter/ probe bus; ground support equipment; performance assurance; and science integration Various test planning options and test method techniques were evaluated in terms of achieving a low-cost program without degrading mission performance or system reliability. The approaches studied and the methodology of the selected approach are defined.

Evaluation of bus emissions generated near bus stops

NASA Astrophysics Data System (ADS)

Yu, Qian; Li, Tiezhu

2014-03-01

The purpose of this research is to demonstrate a methodology for quantification of bus emissions generated near bus stops based on the real-world on-road emissions data collected by the Portable Emission Measurement System (PEMS). Data collection was carried out on an urban diesel bus throughout a bus line under normal operation condition on four work days. Stop influence zone is defined as the area in which the normal bus driving is interrupted by bus stops. The second-by-second data were screened out within the stop influence zone. And the bus running state near a stop was classified into three driving modes, deceleration, idling, and acceleration. Then emission characteristics were analyzed for each mode. Under the idling condition, the emission rates (g s-1) were not constant all the time. The NOX emission rate decreased in the first 4-6 s while the corresponding emission rates of CO2, CO, NOX, and HC increased in the last 4 s of idling. Besides, the influence of bus stop characteristics on emissions was investigated using statistical methods. Platform type, length and location of bus stops showed significant effects on the length of the stop influence zone. However, there were no significant effects on distance-based emission factors.

IMP: Using microsat technology to support engineering research inside of the International Space Station

NASA Astrophysics Data System (ADS)

Carroll, Kieran A.

2000-01-01

This paper describes an International Space Station (ISS) experiment-support facility being developed by Dynacon for the Canadian Space Agency (CSA), based on microsatellite technology. The facility is called the ``Intravehicular Maneuverable Platform,'' or IMP. The core of IMP is a small, free-floating platform (or ``bus'') deployed inside one of the pressurized crew modules of ISS. Exchangeable experimental payloads can then be mounted to the IMP bus, in order to carry out engineering development or demonstration tests, or microgravity science experiments: the bus provides these payloads with services typical of a standard satellite bus (power, attitude control, etc.). The IMP facility takes advantage of unique features of the ISS, such as the Shuttle-based logistics system and the continuous availability of crew members, to greatly reduce the expense of carrying out space engineering experiments. Further cost reduction has been made possible by incorporating technology that Dynacon has developed for use in a current microsatellite mission. Numerous potential payloads for IMP have been identified, and the first of these (a flexible satellite control experiment) is under development by Dynacon and the University of Toronto's Institute for Aerospace Studies, for the CSA. .

Scheduled Peripheral Component Interconnect Arbiter

NASA Technical Reports Server (NTRS)

Nixon, Scott Alan (Inventor)

2015-01-01

Systems and methods are described for arbitrating access of a communication bus. In one embodiment, a method includes performing steps on one or more processors. The steps include: receiving an access request from a device of the communication bus; evaluating a bus schedule to determine an importance of the device based on the access request; and selectively granting access of the communication bus to the device based on the importance of the device.

Multiple IMU system hardware interface design, volume 2

NASA Technical Reports Server (NTRS)

Landey, M.; Brown, D.

1975-01-01

The design of each system component is described. Emphasis is placed on functional requirements unique in this system, including data bus communication, data bus transmitters and receivers, and ternary-to-binary torquing decision logic. Mechanization drawings are presented.

Bus incident reporting, tracking and analysis system

DOT National Transportation Integrated Search

2006-08-01

Many Florida transit systems do little formal analysis of all accidents on an aggregate basis. In many transit system accidents and incidents are not being tracked or analyzed to identify common trends from types of incidents, location, driver, bus r...

Design of belt conveyor electric control device based on CC-link bus

NASA Astrophysics Data System (ADS)

Chen, Goufen; Zhan, Minhua; Li, Jiehua

2016-01-01

In view of problem of the existing coal mine belt conveyor is no field bus communication function, two levels belt conveyor electric control system design is proposed based on field bus. Two-stage belt conveyor electric control system consists of operation platform, PLC control unit, various sensors, alarm device and the water spraying device. The error protection is realized by PLC programming, made use of CC-Link bus technology, the data share and the cooperative control came true between host station and slave station. The real-time monitor was achieved by the touch screen program. Practical application shows that the system can ensure the coalmine production, and improve the automatic level of the coalmine transport equipment.

An experimental study on real time bus arrival time prediction with GPS data

DOT National Transportation Integrated Search

2001-01-01

Bus headway in a rural area is usually much larger than that in an urban area. Providing real-time bus : arrival information could make the public transit system more user-friendly and thus enhance its : competitiveness among various transportation m...

An experimental study on real time bus arrival time prediction with GPS data

DOT National Transportation Integrated Search

1999-01-01

Bus headway in a rural area usually is much larger than that in an urban area. Providing real-time bus arrival information could make the public transit system more user-friendly and thus enhance its competitiveness among various transportation modes...

Implementation of neuromorphic systems: from discrete components to analog VLSI chips (testing and communication issues).

PubMed

Dante, V; Del Giudice, P; Mattia, M

2001-01-01

We review a series of implementations of electronic devices aiming at imitating to some extent structure and function of simple neural systems, with particular emphasis on communication issues. We first provide a short overview of general features of such "neuromorphic" devices and the implications of setting up "tests" for them. We then review the developments directly related to our work at the Istituto Superiore di Sanità (ISS): a pilot electronic neural network implementing a simple classifier, autonomously developing internal representations of incoming stimuli; an output network, collecting information from the previous classifier and extracting the relevant part to be forwarded to the observer; an analog, VLSI (very large scale integration) neural chip implementing a recurrent network of spiking neurons and plastic synapses, and the test setup for it; a board designed to interface the standard PCI (peripheral component interconnect) bus of a PC with a special purpose, asynchronous bus for communication among neuromorphic chips; a short and preliminary account of an application-oriented device, taking advantage of the above communication infrastructure.

A series of small scientific satellite with flexible standard bus

NASA Astrophysics Data System (ADS)

Saito, Hirobumi; Sawai, Syujiro; Sakai, Shin-ichiro; Fukuda, Seisuke; Kitade, Kenji

2009-11-01

Japan Aerospace Exploration Agency has a plan to develop the small satellite standard bus for various scientific missions and disaster monitoring missions. The satellite bus is a class of 250-400 kg mass with three-axis control capability of 0.02∘ accuracy. The science missions include X-ray astronomy missions, planetary telescope missions, and magnetosphere atmosphere missions. In order to adapt the wide range of mission requirements, the satellite bus has to be provided with flexibility. The concepts of modularization, reusability, and product line are applied to the standard bus system. This paper describes the characteristics of the small satellite standard bus which will be firstly launched in 2011.

Advanced Intelligent System Application to Load Forecasting and Control for Hybrid Electric Bus

NASA Technical Reports Server (NTRS)

Momoh, James; Chattopadhyay, Deb; Elfayoumy, Mahmoud

1996-01-01

The primary motivation for this research emanates from providing a decision support system to the electric bus operators in the municipal and urban localities which will guide the operators to maintain an optimal compromise among the noise level, pollution level, fuel usage etc. This study is backed up by our previous studies on study of battery characteristics, permanent magnet DC motor studies and electric traction motor size studies completed in the first year. The operator of the Hybrid Electric Car must determine optimal power management schedule to meet a given load demand for different weather and road conditions. The decision support system for the bus operator comprises three sub-tasks viz. forecast of the electrical load for the route to be traversed divided into specified time periods (few minutes); deriving an optimal 'plan' or 'preschedule' based on the load forecast for the entire time-horizon (i.e., for all time periods) ahead of time; and finally employing corrective control action to monitor and modify the optimal plan in real-time. A fully connected artificial neural network (ANN) model is developed for forecasting the kW requirement for hybrid electric bus based on inputs like climatic conditions, passenger load, road inclination, etc. The ANN model is trained using back-propagation algorithm employing improved optimization techniques like projected Lagrangian technique. The pre-scheduler is based on a Goal-Programming (GP) optimization model with noise, pollution and fuel usage as the three objectives. GP has the capability of analyzing the trade-off among the conflicting objectives and arriving at the optimal activity levels, e.g., throttle settings. The corrective control action or the third sub-task is formulated as an optimal control model with inputs from the real-time data base as well as the GP model to minimize the error (or deviation) from the optimal plan. These three activities linked with the ANN forecaster proving the output to the GP model which in turn produces the pre-schedule of the optimal control model. Some preliminary results based on a hypothetical test case will be presented for the load forecasting module. The computer codes for the three modules will be made available fe adoption by bus operating agencies. Sample results will be provided using these models. The software will be a useful tool for supporting the control systems for the Electric Bus project of NASA.

Advanced Stirling Convertor Dual Convertor Controller Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

NASA Technical Reports Server (NTRS)

Dugala, Gina M.; Taylor, Linda M.; Bell, Mark E.; Dolce, James L.; Fraeman, Martin; Frankford, David P.

2015-01-01

NASA Glenn Research Center (GRC) developed a non-nuclear representation of a Radioisotope Power System (RPS) consisting of a pair of Advanced Stirling Convertors (ASC), a Dual Convertor Controller (DCC) EM (engineering model) 2 & 3, and associated support equipment, which were tested in the Radioisotope Power Systems System Integration Laboratory (RSIL). The DCC was designed by the Johns Hopkins University/Applied Physics Laboratory (JHU/APL) to actively control a pair of Advanced Stirling Convertors (ASC). The first phase of testing included a Dual Advanced Stirling Convertor Simulator (DASCS) which was developed by JHU/APL and simulates the operation and electrical behavior of a pair of ASC's in real time via a combination of hardware and software. RSIL provides insight into the electrical interactions between a representative radioisotope power generator, its associated control schemes, and realistic electric system loads. The first phase of integration testing included the following spacecraft bus configurations: capacitive, battery, and supercapacitor. A load profile, created based on data from several missions, tested the RPS and RSIL ability to maintain operation during load demands above and below the power provided by the RPS. The integration testing also confirmed the DCC's ability to disconnect from the spacecraft when the bus voltage dipped below 22 V or exceeded 36 V. Once operation was verified with the DASCS, the tests were repeated with actual operating ASC's. The goal of this integration testing was to verify operation of the DCC when connected to a spacecraft and to verify the functionality of the newly designed RSIL. The results of these tests are presented in this paper.

Development and Commissioning Results of the Hybrid Sensor Bus Engineering Qualification Model

NASA Astrophysics Data System (ADS)

Hurni, Andreas; Putzer, Phillipp; Roner, Markus; Gurster, Markus; Hulsemeyer, Christian; Lemke, Norbert M. K.

2016-08-01

In order to reduce mass, AIT effort and overall costs of classical point-to-point wired temperature sensor harness on-board spacecraft OHB System AGhas introduced the Hybrid Sensor Bus (HSB) system which interrogates sensors connected in a bus architecture. To use the advantages of electrical as wellas of fiber-optical sensing technologies, HSB is designed as a modular measurement system interrogating digital sensors connected on electricalsensor buses based on I2C and fiber-optical sensor buses based on fiber Bragg grating (FBG) sensors inscribed in optical fibers. Fiber-optical sensor bus networks on-board satellites are well suited for temperature measurement due to low mass, electro-magnetic insensitivity and the capability to embed them inside structure parts. The lightweight FBG sensors inscribed in radiation tolerant fibers can reach every part of the satellite. HSB has been developed in the frame of the ESA ARTES program with European and German co- funding and will be verified as flight demonstrator on- board the German Heinrich Hertz satellite (H2Sat).In this paper the Engineering Qualification Model (EQM) development of HSB and first commissioning results are presented. For the HSB development requirements applicable for telecommunication satellite platforms have been considered. This includes an operation of at least 15 years in a geostationary orbit.In Q3/2016 the qualification test campaign is planned to be carried out. The HSB EQM undergoes a full qualification according to ECSS. The paper concludes with an outlook regarding this HSB flight demonstrator development and its in-orbit verification (IOV) on board H2Sat.

Stand-alone containment analysis of Phébus FPT tests with ASTEC and MELCOR codes: the FPT-2 test.

PubMed

Gonfiotti, Bruno; Paci, Sandro

2018-03-01

During the last 40 years, many studies have been carried out to investigate the different phenomena occurring during a Severe Accident (SA) in a Nuclear Power Plant (NPP). Such efforts have been supported by the execution of different experimental campaigns, and the integral Phébus FP tests were probably some of the most important experiments in this field. In these tests, the degradation of a Pressurized Water Reactor (PWR) fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the findings on these and previous tests, numerical codes such as ASTEC and MELCOR have been developed to analyze the evolution of a SA in real NPPs. After the termination of the Phébus FP campaign, these two codes have been furthermore improved to implement the more recent findings coming from different experimental campaigns. Therefore, continuous verification and validation is still necessary to check that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The aim of the present work is to re-analyze the Phébus FPT-2 test employing the updated ASTEC and MELCOR code versions. The analysis focuses on the stand-alone containment aspects of this test, and three different spatial nodalizations of the containment vessel (CV) have been developed. The paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products (FP) behavior. When possible, a comparison among the results obtained during this work and by different authors in previous work is also performed. This paper is part of a series of publications covering the four Phébus FP tests using a PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3, excluding the FPT-4 one, related to the study of the release of low-volatility FP and transuranic elements from a debris bed and a pool of melted fuel.

An impurity-induced gap system as a quantum data bus for quantum state transfer

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

Chen, Bing, E-mail: chenbingphys@gmail.com; Li, Yong; Song, Z.

2014-09-15

We introduce a tight-binding chain with a single impurity to act as a quantum data bus for perfect quantum state transfer. Our proposal is based on the weak coupling limit of the two outermost quantum dots to the data bus, which is a gapped system induced by the impurity. By connecting two quantum dots to two sites of the data bus, the system can accomplish a high-fidelity and long-distance quantum state transfer. Numerical simulations for finite system show that the numerical and analytical results of the effective coupling strength agree well with each other. Moreover, we study the robustness ofmore » this quantum communication protocol in the presence of disorder in the couplings between the nearest-neighbor quantum dots. We find that the gap of the system plays an important role in robust quantum state transfer.« less

Aircraft Alerting Systems Standardization Study. Volume I. Candidate System Validation and Time-Critical Display Evaluation.

DTIC Science & Technology

1981-01-01

SELCAL FLT ALT ATNI AUO ALT BRK CANSELCAL OVSO CALL CONTRL ALRT _ I7CT be SPLR b 0 11CALL Figure 5.4.4-1 Pilot’s Response Panel Figure 5.4.4-2 Flight...Galley bus off 27 GLY BUS OFF A RP ELEC CYCLE SWITCH Utility bus off 28 UTIL BUS OFF A RP ELEC CYCLE SWITCH Right engine 29 R ENG HYD PUMP A RP HYD...CYCLE SWITCH hydraulic pump Left engine 30 L ENG FIRE DET A RP FIRE RP FIRE fire detector Left brake overheat 31 L BRAKE OVHT A RP BRK RP BRK Right

A preliminary survey analysis of school shuttle bus system towards smart mobility solutions

NASA Astrophysics Data System (ADS)

Yue, Wong Seng; Hoy, Cheong Wan; Chye, Koh Keng

2017-10-01

Mobility and accessibility are crucial indicators of urban development. Public transport in the urban areas came into existence to fulfil transportation needs as well as mobility and accessibility demands. Ridership can be affected by the quality and quantity of transit service. However, technical improvements are needed for such as real-time bus information, controlling run time and headway delay. Thus, this paper is aimed to carry out a preliminary survey to determine the problems of school shuttle bus that faced by the students in a selected educational institution, their perceptions of using shuttle bus tracking and information mobile application and impacts of real-time information of public transits on bus ridership and towards smart mobility solutions. Efficient public transportation system needs further investigation about the role of mobile application for the bus tracking system in supporting smart mobility actions and real-time information. The proposed application also provides a smart solution for the management of public infrastructures and urban facilities in Malaysia in future. Eventually, this study opens an opportunity to improve Malaysian quality of life on the public value that created for the city as a whole.

Measurement and comparison of Bangkok diesel bus emissions and performance using on-board equipment

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

Burnette, A.D.; Kishan, S.; Wangwongwatana, S.

1997-12-31

An on-board measurement system was assembled and used to compare the emissions and performance of buses in Bangkok, Thailand under actual driving conditions. Three similar buses were compared: one using an engine without special emissions control design, one with an engine meeting Euro 1 standards, and one with an engine meeting Euro 2 standards. As the buses drove their routes, second-by-second data were collected for engine rpm, throttle position, vehicle speed, exhaust concentrations of hydrocarbons, carbon monoxide, carbon dioxide, oxygen, nitric oxide, and exhaust opacity. Vehicle performance data were calculated using algorithms developed during previous driving studies in Bangkok. Grammore » per liter of fuel used emission factors were developed for gaseous pollutants using combustion calculations and these were translated into gram per kilometer traveled emission factors using the fuel efficiency data for the buses. Smoke data were left in terms of opacity. Test results are designed to be used to compare the cost benefit of upgrading buses with no emissions controls to Euro 1 or Euro 2 technologies. Ongoing tests will help bus companies determine the benefit of incremental improvements to bus engines and other emissions reduction strategies.« less

Integrated corridor management initiative : demonstration phase evaluation, Dallas benefit-cost analysis test plan.

DOT National Transportation Integrated Search

2000-12-01

The focus of this paper is on advanced public transportation systems (APTS) technologies. It assesses the extent of their deployment and judges their degree of success. It covers APTS technologies in use only by bus and demand responsive service oper...

Analysis of a dc bus system with a nonlinear constant power load and its delayed feedback control.

PubMed

Konishi, Keiji; Sugitani, Yoshiki; Hara, Naoyuki

2014-02-01

This paper tackles a destabilizing problem of a direct-current (dc) bus system with constant power loads, which can be considered a fundamental problem of dc power grid networks. The present paper clarifies scenarios of the destabilization and applies the well-known delayed-feedback control to the stabilization of the destabilized bus system on the basis of nonlinear science. Further, we propose a systematic procedure for designing the delayed feedback controller. This controller can converge the bus voltage exactly on an unstable operating point without accurate information and can track it using tiny control energy even when a system parameter, such as the power consumption of the load, is slowly varied. These features demonstrate that delayed feedback control can be considered a strong candidate for solving the destabilizing problem.

Cops, cameras, and enclosures : a synthesis of the effectiveness of methods to provide enhanced security for bus operators

DOT National Transportation Integrated Search

2001-05-31

The safety of operators and passengers is a primary concern of transit systems and has become an increasingly important issue to transit bus operators themselves. Many transit agencies have experienced incidents of assaults against their bus operator...

Comparison of on-road emissions for hybrid and regular transit buses.

PubMed

Hallmark, Shauna L; Wang, Bo; Sperry, Robert

2013-10-01

Hybrid technology offers an attractive option for transit buses, since it has the potential to significantly reduce operating costs for transit agencies. The main impetus behind use of hybrid transit vehicles is fuel savings and reduced emissions. Laboratory tests have indicated that hybrid transit buses can have significantly lower emissions compared with conventional transit buses. However the number of studies is limited and laboratory tests may not represent actual driving conditions, since in-use vehicle operation differs from laboratory test cycles. This paper describes an on-road evaluation of in-use emission differences between hybrid-electric and conventional transit buses for the Ames, Iowa transit authority, CyRide. Emissions were collected on-road using a portable emissions monitoring system (PEMS) for three hybrid and two control buses. Emissions were collected for at least one operating bus day. Each bus was evaluated over the same route pattern, which utilizes the same driver. The number of passengers embarking or disembarking at each stop was collected by an on-board data collector so that passenger load could be included. Vehicle emissions are correlated to engine load demand, which is a function of factors such as vehicle load, speed, and acceleration. PEMS data are provided second by second and vehicle-specific power (VSP) was calculated for each row of data. Instantaneous data were stratified into the defined VSP bins and then average modal emission rates and standard errors were calculated for each bus for each pollutant. Pollutants were then compared by bus type. Carbon dioxide, carbon monoxide, and hydrocarbon emissions were higher for the regular buses across most VSP bins than for the hybrid buses. Nitrogen oxide emissions were unexpectedly higher for the hybrid buses than for the control buses.

Evaluation of Effective Factors on Travel Time in Optimization of Bus Stops Placement Using Genetic Algorithm

NASA Astrophysics Data System (ADS)

Bargegol, Iraj; Ghorbanzadeh, Mahyar; Ghasedi, Meisam; Rastbod, Mohammad

2017-10-01

In congested cities, locating and proper designing of bus stops according to the unequal distribution of passengers is crucial issue economically and functionally, since this subject plays an important role in the use of bus system by passengers. Location of bus stops is a complicated subject; by reducing distances between stops, walking time decreases, but the total travel time may increase. In this paper, a specified corridor in the city of Rasht in north of Iran is studied. Firstly, a new formula is presented to calculate the travel time, by which the number of stops and consequently, the travel time can be optimized. An intended corridor with specified number of stops and distances between them is addressed, the related formulas to travel time are created, and its travel time is calculated. Then the corridor is modelled using a meta-heuristic method in order that the placement and the optimal distances of bus stops for that are determined. It was found that alighting and boarding time along with bus capacity are the most effective factors affecting travel time. Consequently, it is better to have more concentration on indicated factors for improving the efficiency of bus system.

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

Chandler, K.; Eudy, L.

This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three new diesel buses operating from the same location. The prototype fuel cell bus was manufactured by Van Hool and ISE Corp. and features an electric hybrid drive system with a UTC Power PureMotion 120 Fuel Cell Power System and ZEBRA batteries for energy storage. The fuel cell bus started operation in April 2007, and evaluation results through October 2009 are provided in this report.

Interface of the transport systems research vehicle monochrome display system to the digital autonomous terminal access communication data bus

NASA Technical Reports Server (NTRS)

Easley, W. C.; Tanguy, J. S.

1986-01-01

An upgrade of the transport systems research vehicle (TSRV) experimental flight system retained the original monochrome display system. The original host computer was replaced with a Norden 11/70, a new digital autonomous terminal access communication (DATAC) data bus was installed for data transfer between display system and host, while a new data interface method was required. The new display data interface uses four split phase bipolar (SPBP) serial busses. The DATAC bus uses a shared interface ram (SIR) for intermediate storage of its data transfer. A display interface unit (DIU) was designed and configured to read from and write to the SIR to properly convert the data from parallel to SPBP serial and vice versa. It is found that separation of data for use by each SPBP bus and synchronization of data tranfer throughout the entire experimental flight system are major problems which require solution in DIU design. The techniques used to accomplish these new data interface requirements are described.

Results of an electrical power system fault study

NASA Technical Reports Server (NTRS)

Dugal-Whitehead, Norma R.; Johnson, Yvette B.

1992-01-01

NASA-Marshall conducted a study of electrical power system faults with a view to the development of AI control systems for a spacecraft power system breadboard. The results of this study have been applied to a multichannel high voltage dc spacecraft power system, the Large Autonomous Spacecraft Electrical Power System (LASEPS) breadboard. Some of the faults encountered in testing LASEPS included the shorting of a bus an a falloff in battery cell capacity.

A study of headway maintenance for bus routes : causes and effects of "bus bunching" in extensive and congested service areas.

DOT National Transportation Integrated Search

2012-07-01

A healthy and efficient public transit system is indispensable to reduce congestion, emissions, energy consumption, and car : dependency in urban areas. The objective of this research is to 1) develop methods to evaluate and visualize bus service rel...

Autonomous Cryogenics Loading Operations Simulation Software: Knowledgebase Autonomous Test Engineer

NASA Technical Reports Server (NTRS)

Wehner, Walter S., Jr.

2013-01-01

Working on the ACLO (Autonomous Cryogenics Loading Operations) project I have had the opportunity to add functionality to the physics simulation software known as KATE (Knowledgebase Autonomous Test Engineer), create a new application allowing WYSIWYG (what-you-see-is-what-you-get) creation of KATE schematic files and begin a preliminary design and implementation of a new subsystem that will provide vision services on the IHM (Integrated Health Management) bus. The functionality I added to KATE over the past few months includes a dynamic visual representation of the fluid height in a pipe based on number of gallons of fluid in the pipe and implementing the IHM bus connection within KATE. I also fixed a broken feature in the system called the Browser Display, implemented many bug fixes and made changes to the GUI (Graphical User Interface).

Transit bus stop pedestrian warning application : requirements document.

DOT National Transportation Integrated Search

2016-08-01

This document describes the System Requirements for the Transit Bus Stop Pedestrian Warning (TSPW) application. The requirements describe the system of interest for the implementation team including the required functions and performance along with t...

A Feeder-Bus Dispatch Planning Model for Emergency Evacuation in Urban Rail Transit Corridors

PubMed Central

Wang, Yun; Yan, Xuedong; Zhou, Yu; Zhang, Wenyi

2016-01-01

The mobility of modern metropolises strongly relies on urban rail transit (URT) systems, and such a heavy dependence causes that even minor service interruptions would make the URT systems unsustainable. This study aims at optimally dispatching the ground feeder-bus to coordinate with the urban rails’ operation for eliminating the effect of unexpected service interruptions in URT corridors. A feeder-bus dispatch planning model was proposed for the collaborative optimization of URT and feeder-bus cooperation under emergency situations and minimizing the total evacuation cost of the feeder-buses. To solve the model, a concept of dummy feeder-bus system is proposed to transform the non-linear model into traditional linear programming (ILP) model, i.e., traditional transportation problem. The case study of Line #2 of Nanjing URT in China was adopted to illustrate the model application and sensitivity analyses of the key variables. The modeling results show that as the evacuation time window increases, the total evacuation cost as well as the number of dispatched feeder-buses decrease, and the dispatched feeder-buses need operate for more times along the feeder-bus line. The number of dispatched feeder-buses does not show an obvious change with the increase of parking spot capacity and time window, indicating that simply increasing the parking spot capacity would cause huge waste for the emergent bus utilization. When the unbalanced evacuation demand exists between stations, the more feeder-buses are needed. The method of this study will contribute to improving transportation emergency management and resource allocation for URT systems. PMID:27676179

A program downloader and other utility software for the DATAC bus monitor unit

NASA Technical Reports Server (NTRS)

Novacki, Stanley M., III

1987-01-01

A set or programs designed to facilitate software testing on the DATAC Bus Monitor is described. By providing a means to simplify program loading, firmware generation, and subsequent testing of programs, the overhead involved in software evaluation is reduced and that time is used more productively in performance, analysis and improvement of current software.

76 FR 46893 - Agency Information Collection Activity Under OMB Review

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-03

... manufacturer certifies to a FTA grantee that the bus the grantee is purchasing has been tested at the Center. Also, grantees about to purchase a bus use this report to assist them in making their purchasing decisions. PTI maintains a reference file for all the test reports which are made available to the public...

Body Mass Index is a Poor Predictor of Bedside Appendix Ultrasound Success or Accuracy

PubMed Central

Lam, Samuel H.F.; Kerwin, Christopher; Konicki, P. John; Goodwine, Diana; Lambert, Michael J.

2016-01-01

Introduction The objective of this study was to determine whether there is a relationship between body mass index (BMI) and success or accuracy rate of beside ultrasound (BUS) for the diagnosis of appendicitis. Methods Patients four years of age and older presenting to the emergency department with suspected appendicitis were eligible. Enrollment was by convenience sampling. After informed consent, BUS was performed by trained emergency physicians who had undergone a minimum of one-hour didactic training on the use of BUS to diagnose appendicitis. We ascertained subject outcomes by a combination of medical record review and telephone follow up. Calculated BMI for adults and children were divided into four categories (underweight, normal, overweight, obese) according to Centers for Disease Control and Prevention classifications. Results A total of 125 subjects consented for the study, and 116 of them had adequate image data for final analysis. Seventy (60%) of the subjects were children. Prevalence of appendicitis was 39%. Fifty-two (45%) of the BUS studies were diagnostic (successful). Overall accuracy rate was 75%. Analysis by chi-square test or Mann-Whitney U test did not find any significant correlation between BMI category and BUS success. Similarly, there was no significant correlation between BMI category and BUS accuracy. The same conclusion was reached when children and adults were analyzed separately, or when subjects were dichotomized into underweight/normal and overweight/obese categories. Conclusion BMI category alone is a poor predictor of appendix BUS success or accuracy. PMID:27429696

Static power reduction for midpoint-terminated busses

DOEpatents

Coteus, Paul W [Yorktown Heights, NY; Takken, Todd [Brewster, NY

2011-01-18

A memory system is disclosed which is comprised of a memory controller and addressable memory devices such as DRAMs. The invention provides a programmable register to control the high vs. low drive state of each bit of a memory system address and control bus during periods of bus inactivity. In this way, termination voltage supply current can be minimized, while permitting selected bus bits to be driven to a required state. This minimizes termination power dissipation while not affecting memory system performance. The technique can be extended to work for other high-speed busses as well.

Research on fuel cell and battery hybrid bus system parameters based on ADVISOR

NASA Astrophysics Data System (ADS)

Lai, Lianfeng; Lu, Youwen; Guo, Weiwei; Lin, Yuxiang; Xie, Yichun; Zheng, Liping; Chen, Wei; Liang, Boshan

2018-06-01

This paper aims at the fuel cell and battery hybrid automobile, based on one bus parameters, considers their own characteristics of fuel cell and battery and power demand when automobiles start, accelerate, climb, brake and other different working conditions, calculate the hybrid bus system parameters that match the fuel cell/battery., and ADVISOR is used is to verify simulation. The results show that the parameters of power drive system of this electric automobile are reasonable, and can meet the requirements of dynamic design indexes.

46 CFR 28.855 - Electrical distribution systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Electrical distribution systems. 28.855 Section 28.855... FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.855 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

46 CFR 28.360 - Electrical distribution systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Electrical distribution systems. 28.360 Section 28.360... Operate With More Than 16 Individuals on Board § 28.360 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

46 CFR 28.360 - Electrical distribution systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Electrical distribution systems. 28.360 Section 28.360... Operate With More Than 16 Individuals on Board § 28.360 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

46 CFR 28.360 - Electrical distribution systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Electrical distribution systems. 28.360 Section 28.360... Operate With More Than 16 Individuals on Board § 28.360 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

46 CFR 28.855 - Electrical distribution systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Electrical distribution systems. 28.855 Section 28.855... FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.855 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

46 CFR 28.360 - Electrical distribution systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Electrical distribution systems. 28.360 Section 28.360... Operate With More Than 16 Individuals on Board § 28.360 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

46 CFR 28.855 - Electrical distribution systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Electrical distribution systems. 28.855 Section 28.855... FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.855 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

46 CFR 28.855 - Electrical distribution systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Electrical distribution systems. 28.855 Section 28.855... FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.855 Electrical distribution systems. (a) Each electrical distribution system which has a neutral bus or conductor must have the neutral bus or conductor...

Heavy Duty Diesel Truck and Bus Hybrid Powertrain Study

DTIC Science & Technology

2012-03-01

electric 22 ft. bus that offers greater range than battery-electric buses can provide. Designed to seat 22 passengers plus standees, this Ebus model...system that has both parallel and series operating modes. The relatively low volume of many truck and bus designs has inhibited the development of...that battery packs need to be designed for 50,000 lifetime energy storage cycles in a hybrid transit bus vs. just 3,600 cycles in the typical

Diagnostic procedures for Trend Monitoring System (TMS) communications. [coaxial cable bus system

NASA Technical Reports Server (NTRS)

Brown, J. S.; Lenker, M. D.

1979-01-01

A prototype coaxial cable bus communications sytem was developed to support the trend monitoring system (TMS). Troubleshooting procedures are described at the system level. The procedures can be used by repair personnel to isolate a fault in the TMS and to restore the system to operation by swapping out failed components.

Wireless global positioning system fleet tracking system at the University at Albany.

DOT National Transportation Integrated Search

2014-07-01

This report provides an overview of the project undertaken at the University at Albany to make alternative transportation a more : viable option by implementing a GPS Tracking System on the University bus fleet and broadcasting the bus locations to c...

Bus Fare Collection System Assessment

DOT National Transportation Integrated Search

1986-01-01

An assessment was conducted to examine the impact that rising fare levels are having on bus transit fare collection systems. Problems have been reported with regard to the handling of dollar bills and lost revenue. This report addresses these problem...

Performance of school bus retrofit systems: ultrafine particles and other vehicular pollutants.

PubMed

Zhang, Qunfang; Zhu, Yifang

2011-08-01

This study evaluated the performance of retrofit systems for diesel-powered school buses, a diesel oxidation catalyst (DOC) muffler and a spiracle crankcase filtration system (CFS), regarding ultrafine particles (UFPs) and other air pollutants from tailpipe emissions and inside bus cabins. Tailpipe emissions and in-cabin air pollutant levels were measured before and after retrofitting when the buses were idling and during actual pick-up/drop off routes. Retrofit systems significantly reduced tailpipe emissions with a reduction of 20-94% of total particles with both DOC and CFS installed. However, no unequivocal decrease was observed for in-cabin air pollutants after retrofitting. The AC/fan unit and the surrounding air pollutant concentrations played more important roles for determining the in-cabin air quality of school buses than did retrofit technologies. Although current retrofit systems reduce children's exposure while waiting to board at a bus station, retrofitting by itself does not protect children satisfactorily from in-cabin particle exposures. Turning on the bus engine increased in-cabin UFP levels significantly only when the wind blew from the bus' tailpipe toward its hood with its windows open. This indicated that wind direction and window position are significant factors determining how much self-released tailpipe emissions may penetrate into the bus cabin. The use of an air purifier was found to remove in-cabin particles by up to 50% which might be an alternative short-to-medium term strategy to protect children's health.

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

NASA Technical Reports Server (NTRS)

1999-01-01

KSC workers, with Center Director Roy Bridges (at right next to bus), head for the open door of the Zero Emissions (ZE) transit bus and a ride around the center. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available to employees for viewing and a ride, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

PMU Data Integrity Evaluation through Analytics on a Virtual Test-Bed

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

Olama, Mohammed M.; Shankar, Mallikarjun

Power systems are rapidly becoming populated by phasor measurement units (PMUs) in ever increasing numbers. PMUs are critical components of today s energy management systems, designed to enable near real-time wide area monitoring and control of the electric power system. They are able to measure highly accurate bus voltage phasors as well as branch current phasors incident to the buses at which PMUs are equipped. Synchrophasor data is used for applications varying from state estimation, islanding control, identifying outages, voltage stability detection and correction, disturbance recording, and others. However, PMU-measured readings may suffer from errors due to meter biases ormore » drifts, incorrect configurations, or even cyber-attacks. Furthermore, the testing of early PMUs showed a large disparity between the reported values from PMUs provided by different manufacturers, particularly when frequency was off-nominal, during dynamic events, and when harmonic/inter-harmonic content was present. Detection and identification of PMU gross measurement errors are thus crucial in maintaining highly accurate phasor readings throughout the system. In this paper, we present our work in conducting analytics to determine the trustworthiness and worth of the PMU readings collected across an electric network system. By implementing the IEEE 118 bus test case on a virtual test bed (VTB) , we are able to emulate PMU readings (bus voltage and branch current phasors in addition to bus frequencies) under normal and abnormal conditions using (virtual) PMU sensors deployed across major substations in the network. We emulate a variety of failures such as bus, line, transformer, generator, and/or load failures. Data analytics on the voltage phase angles and frequencies collected from the PMUs show that specious (or compromised) PMU device(s) can be identified through abnormal behaviour by comparing the trend of its frequency and phase angle reading with the ensemble of all other PMU readings in the network. If the reading trend of a particular PMU deviates from the weighted average of the reading trends of other PMUs at nearby substations, then it is likely that the PMU is malfunctioning. We assign a weight to each PMU denoting how electric-topology-wise close it is from where the PMU under consideration is located. The closer a PMU is, the higher the weight it has. To compute the closeness between two nodes in the power network, we employ a form of the resistance distance metric. It computes the electrical distance by taking into consideration the underlying topology as well as the physical laws that govern the electrical connections or flows between the network components. The detection accuracy of erroneous PMUs should be improved by employing this metric. We present results to validate the proposed approach. We also discuss the effectiveness of using an end-to-end VTB approach that allows us to investigate different types of failures and their responses as seen by the ensemble of PMUs. The collected data on certain types of events may be amenable to certain types of analysis (e.g., alerting for sudden changes can be done on a small window of data) and hence determine the data analytics architectures is required to evaluate the streaming PMU data.« less

Design Report for Isolated RS-485 Bus Node

DTIC Science & Technology

2016-07-01

controlled wired RS-485 network. The Android-based smartphone or tablet is used in conjunction with a USB to serial bridge to operate as the bus master in...Android-based smartphone or tablet is used in conjunction with a USB to serial bridge to operate as the bus master in the system. The Android device

Development of a Microcomputer-Based Adaptive Testing System. Phase I. Specification of Requirements and Preliminary Design.

DTIC Science & Technology

1982-06-30

treatments, and cure (or kill ) a patient. Administratively, the items were in a multiple-choice format and the simulation proceeded by branching...Discs: dual 5 1/4 inch floppies (IM) Bus: N/A Operating System: CP/M, MmmOST Price: $3,495 -14 ~-174- - ’i~ Model 820 Xerox 1341 West Mockingbird Lane

Analysis of real-time variables affecting children's exposure to diesel-related pollutants during school bus commutes in Los Angeles

NASA Astrophysics Data System (ADS)

Sabin, Lisa D.; Kozawa, Kathleen; Behrentz, Eduardo; Winer, Arthur M.; Fitz, Dennis R.; Pankratz, David V.; Colome, Steven D.; Fruin, Scott A.

Variables affecting children's exposure during school bus commutes were investigated using real-time measurements of black carbon (BC), particle-bound polycyclic aromatic hydrocarbons (PB-PAH) and nitrogen dioxide (NO 2) inside 3 conventional diesel school buses, a particle trap-outfitted (TO) diesel school bus and a compressed natural gas (CNG) school bus, while traveling along an urban Los Angeles Unified School District bus route. A video camera was mounted at the front of each bus to record roadway conditions ahead of the bus during each commute. The videotapes from 12 commutes, in conjunction with pollutant concentration time series, were used to determine the influence of variables such as vehicles being followed, bus type and roadway type on pollutant concentrations inside the bus. For all buses tested, the highest concentrations of BC, PB-PAH and NO 2 were observed when following a diesel school bus, especially if that bus was emitting visible exhaust. This result was important because other diesel school buses were responsible for the majority of the diesel vehicle encounters, primarily due to caravanning with each other when leaving a school at the same time. Compared with following a gasoline vehicle or no target, following a smoky diesel school bus yielded BC and PB-PAH concentrations inside the cabin 8 and 11 times higher, respectively, with windows open, and ˜1.8 times higher for both pollutants with windows closed. When other diesel vehicles were not present, pollutant concentrations were highest inside the conventional diesel buses and lowest inside the CNG bus, while the TO diesel bus exhibited intermediate concentrations. Differences in pollutant concentrations between buses were most pronounced with the bus windows closed, and were attributed to a combination of higher concentrations in the exhaust and higher exhaust gas intrusion rates for the conventional diesel buses. Conventional diesel school buses can have a double exposure impact on commuting children: first, exposures to the exhaust from other nearby diesel school buses and, second, exposure to the bus's own exhaust through "self-pollution".

Countermeasures for Developing New Energy Bus Standards in China

NASA Astrophysics Data System (ADS)

Shi, Xin

2018-01-01

With the rapid development of new energy vehicle technology, new energy bus has become more and more popular in China, and the relevant standards and policy are urgently needed to guide the market. According to the assessment of the development situation on new energy vehicle technology and new energy bus, combing with traffic policy guidance and the development trend of new energy vehicles, this paper aims to put forward the countermeasures of the new energy bus standard in China, including standard system, key standards and relevant recommendations. Research result is expected to provide decision support for the wide application of new energy bus in China.

State and Federal project development procedures for bus rapid transit : managing differences and reducing implementation delays

DOT National Transportation Integrated Search

2011-08-01

This report documents an investigation into the transportation project development process in the : context of the implementation of bus rapid transit systems on the State Highway System as well as such : systems being part of the Federal New Starts ...

Synchronizing Data-Bus Messages

NASA Technical Reports Server (NTRS)

Harris, L. H.

1985-01-01

Adapter allows communications among as many as 30 data processors without central bus controller. Adapter improves reliability of multiprocessor system by eliminating point of failure that causes entire system to fail. Scheme prevents data collisions and eliminates nonessential polling, thereby reducing power consumption.

49 CFR 611.301 - Small Starts eligibility.

Code of Federal Regulations, 2014 CFR

2014-10-01

... extension to a fixed guideway, or a corridor-based bus rapid transit system, a project must: (1) Be a Small... extension to a fixed guideway, or a corridor-based bus rapid system, a project must: (1) Be a Small Starts...

49 CFR 611.301 - Small Starts eligibility.

Code of Federal Regulations, 2013 CFR

2013-10-01

... extension to a fixed guideway, or a corridor-based bus rapid transit system, a project must: (1) Be a Small... extension to a fixed guideway, or a corridor-based bus rapid system, a project must: (1) Be a Small Starts...

Multibus-based parallel processor for simulation

NASA Technical Reports Server (NTRS)

Ogrady, E. P.; Wang, C.-H.

1983-01-01

A Multibus-based parallel processor simulation system is described. The system is intended to serve as a vehicle for gaining hands-on experience, testing system and application software, and evaluating parallel processor performance during development of a larger system based on the horizontal/vertical-bus interprocessor communication mechanism. The prototype system consists of up to seven Intel iSBC 86/12A single-board computers which serve as processing elements, a multiple transmission controller (MTC) designed to support system operation, and an Intel Model 225 Microcomputer Development System which serves as the user interface and input/output processor. All components are interconnected by a Multibus/IEEE 796 bus. An important characteristic of the system is that it provides a mechanism for a processing element to broadcast data to other selected processing elements. This parallel transfer capability is provided through the design of the MTC and a minor modification to the iSBC 86/12A board. The operation of the MTC, the basic hardware-level operation of the system, and pertinent details about the iSBC 86/12A and the Multibus are described.

Space station common module thermal management: Design and construction of a test bed

NASA Technical Reports Server (NTRS)

Barile, R. G.

1986-01-01

In this project, a thermal test bed was designed, simulated, and planned for construction. The thermal system features interior and exterior thermal loads and interfacing with the central-radiator thermal bus. Components of the test bed include body mounted radiator loop with interface heat exchangers (600 Btu/hr); an internal loop with cabin air-conditioning and cold plates (3400 Btu/hr); interface heat exchangers to the central bus (13,000 Btu/hr); and provisions for new technology including advanced radiators, thermal storage, and refrigeration. The apparatus will be mounted in a chamber, heated with lamps, and tested in a vacuum chamber with LN2-cooled walls. Simulation of the test bed was accomplished using a DEC PRO 350 computer and the software package TK! olver. Key input variables were absorbed solar radiation and cold plate loads. The results indicate temperatures on the two loops will be nominal when the radiation and cold plate loads are in the range of 25% to 75% of peak loads. If all loads fall to zero, except the cabin air system which was fixed, the radiator fluid will drop below -100 F and may cause excessive pressure drop. If all loads reach 100%, the cabin air temperature could rise to 96 F.

Vehicle occupants' exposure to aromatic volatile organic compounds while commuting on an urban-suburban route in Korea.

PubMed

Jo, W K; Choi, S J

1996-08-01

This study identified in-auto and in-bus exposures to six selected aromatic volatile organic compounds (VOCs) for commutes on an urban-suburban route in Korea. A bus-service route was selected to include three segments of Taegu and one suburban segment (Hayang) to satisfy the criteria specified for this study. This study indicates that motor vehicle exhaust and evaporative emissions are major sources of both auto and bus occupants' exposures to aromatic VOCs in both Taegu and Hayang. A nonparametric statistical test (Wilcoxon test) showed that in-auto benzene levels were significantly different from in-bus benzene levels for both urban-segment and suburban-segment commutes. The test also showed that the benzene-level difference between urban-segment and suburban-segment commutes was significant for both autos and buses. An F-test showed the same statistical results for the comparison of the summed in-vehicle concentration of the six target VOCs (benzene, toluene, ethylbenzene, and o,m,p-xylenes) as those for the comparison of the in-vehicle benzene concentration. On the other hand, the in-vehicle benzene level only and the sum were not significantly different among the three urban-segment commutes and between the morning and evening commutes. The in-auto VOC concentrations were intermediate between the results for the Los Angeles and Boston. The in-bus VOC concentrations were about one-tenth of the Taipei, Taiwan results.

Hydrogen-oxygen driven Zero Emissions bus drives around KSC Visitor Complex

NASA Technical Reports Server (NTRS)

1999-01-01

The Zero Emissions (ZE) transit bus passes a mock-up orbiter named Explorer on a trek through the KSC Visitor Complex. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. The ZE bus is being used on tour routes at the KSC Visitor Complex for two days to introduce the public to the concept.

Effect of distributed generation installation on power loss using genetic algorithm method

NASA Astrophysics Data System (ADS)

Hasibuan, A.; Masri, S.; Othman, W. A. F. W. B.

2018-02-01

Injection of the generator distributed in the distribution network can affect the power system significantly. The effect that occurs depends on the allocation of DG on each part of the distribution network. Implementation of this approach has been made to the IEEE 30 bus standard and shows the optimum location and size of the DG which shows a decrease in power losses in the system. This paper aims to show the impact of distributed generation on the distribution system losses. The main purpose of installing DG on a distribution system is to reduce power losses on the power system.Some problems in power systems that can be solved with the installation of DG, one of which will be explored in the use of DG in this study is to reduce the power loss in the transmission line. Simulation results from case studies on the IEEE 30 bus standard system show that the system power loss decreased from 5.7781 MW to 1,5757 MW or just 27,27%. The simulated DG is injected to the bus with the lowest voltage drop on the bus number 8.

Battery performance of the SKYNET 4A spacecraft during the first six years of on station operation

NASA Technical Reports Server (NTRS)

Johnson, P. J.; Francis, N. R.

1996-01-01

The SKYNET 4A spacecraft is a three-axis stabilized geostationary earth-orbiting military communications satellite which was launched on 1 Jan. 1990 aboard a Titan 3 launch vehicle. The power subsystem is a twin bus, twin battery semi-regulated system and is equipped with one 28-cell, 35 Ampere-hour battery per bus. The cells were manufactured by Gates Aerospace Batteries of Gainesville, FL, and the batteries were built, tested and integrated by British Aerospace Space Systems Ltd. This paper presents a brief survey of the first six years of on-station operation and the operational battery management strategy that has been adopted. Thermal management constraints have led to an unconventional battery operational regime. However, no sign of degradation is evident and the observed spacecraft battery performance remains nominal.

76 FR 27172 - Notice of Request for the Reinstatement of an Information Collection

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-10

... the bus the grantee is purchasing has been tested at the Center. Also, grantees about to purchase a bus use this report to assist them in making their purchasing decisions. PTI maintains a reference...

Orbiter multiplexer-demultiplexer (MDM)/Space Lab Bus Interface Unit (SL/BIU) serial data interface evaluation, volume 2

NASA Technical Reports Server (NTRS)

Tobey, G. L.

1978-01-01

Tests were performed to evaluate the operating characteristics of the interface between the Space Lab Bus Interface Unit (SL/BIU) and the Orbiter Multiplexer-Demultiplexer (MDM) serial data input-output (SIO) module. This volume contains the test equipment preparation procedures and a detailed description of the Nova/Input Output Processor Simulator (IOPS) software used during the data transfer tests to determine word error rates (WER).

An evaluation plan of bus architectures and protocols using the NASA Ames intelligent redundant actuation system

NASA Technical Reports Server (NTRS)

Defeo, P.; Chen, M.

1987-01-01

Means for evaluating data bus architectures and protocols for highly integrated flight control system applications are needed. Described are the criteria and plans to do this by using the NASA/Ames Intelligent Redundant Actuation System (IRAS) experimental set-up. Candidate bus architectures differ from one another in terms of: topology, access control, message transfer schemes, message characteristics, initialization. data flow control, transmission rates, fault tolerance, and time synchronization. The evaluation criteria are developed relative to these features. A preliminary, analytical evaluation of four candidate busses (MIL-STD-1553B, DATAC, Ethernet, and HSIS) is described. A bus must be exercised in a real-time environment to evaluate its dynamic characteristics. A plan for real-time evaluation of these four busses using a combination of hardware and simulation techniques is presented.

Integration of a MicroCAT Propulsion System and a PhoneSat Bus into a 1.5U CubeSat

NASA Technical Reports Server (NTRS)

Agasid, Elwood Floyd; Perez, Andres Dono; Gazulla, Oriol Tintore; Trinh, Greenfield Tran; Uribe, Eddie Anthony; Keidar, Michael; Haque, Samudra; Teel, George

2014-01-01

NASA Ames Research Center and the George Washington University have developed an electric propulsion subsystem that can be integrated into the PhoneSat bus. Experimental tests have shown a reliable performance by firing three different thrusters at various frequencies in vacuum conditions. The three thrusters were controlled by a SmartPhone that was running the PhoneSat software. The subsystem is fully operational and it requires low average power to function (about 0.1 W). The interface consists of a microcontroller that sends a trigger pulses to the PPU (Plasma Processing Unit), which is responsible for the thruster operation. Frequencies ranging from 1 to 50Hz have been tested, showing a strong flexibility. A SmartPhone acts as the main user interface for the selection of commands that control the entire system. The micro cathode arc thruster MicroCAT provides a high 1(sub sp) of 3000s that allows a 4kg satellite to obtain a (delta)V of 300m/s. The system mass is only 200g with a total of volume of 200(cu cm). The propellant is based on a solid cylinder made of Titanium, which is the cathode at the same time. This simplicity in the design avoids miniaturization and manufacturing problems. The characteristics of this thruster allow an array of MicroCATs to perform attitude control and orbital correcton maneuvers that will open the door for the implementation of an extensive collection of new mission concepts and space applications for CubeSats. NASA Ames is currently working on the integration of the system to fit the thrusters and PPU inside a 1.5U CubeSat together with the PhoneSat bus into a 1.5U CubeSat. This satellite is intended to be deployed from the ISS in 2015 and test the functionality of the thrusters by spinning the satellite around its long axis and measure the rotational speed with the phone byros. This test flight will raise the TRL of the propulsion system from 5 to 7 and will be a first test for further CubeSats with propulsion systems, a key subsystem for long duration or interplanetary CubeSat missions.

An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

PubMed Central

Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M. A.

2014-01-01

This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

Life-cycle assessment of diesel, natural gas and hydrogen fuel cell bus transportation systems

NASA Astrophysics Data System (ADS)

Ally, Jamie; Pryor, Trevor

The Sustainable Transport Energy Programme (STEP) is an initiative of the Government of Western Australia, to explore hydrogen fuel cell technology as an alternative to the existing diesel and natural gas public transit infrastructure in Perth. This project includes three buses manufactured by DaimlerChrysler with Ballard fuel cell power sources operating in regular service alongside the existing natural gas and diesel bus fleets. The life-cycle assessment (LCA) of the fuel cell bus trial in Perth determines the overall environmental footprint and energy demand by studying all phases of the complete transportation system, including the hydrogen infrastructure, bus manufacturing, operation, and end-of-life disposal. The LCAs of the existing diesel and natural gas transportation systems are developed in parallel. The findings show that the trial is competitive with the diesel and natural gas bus systems in terms of global warming potential and eutrophication. Emissions that contribute to acidification and photochemical ozone are greater for the fuel cell buses. Scenario analysis quantifies the improvements that can be expected in future generations of fuel cell vehicles and shows that a reduction of greater than 50% is achievable in the greenhouse gas, photochemical ozone creation and primary energy demand impact categories.

An optimal control strategy for DC bus voltage regulation in photovoltaic system with battery energy storage.

PubMed

Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A

2014-01-01

This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods.

Advanced Stirling Convertor Control Unit Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

NASA Technical Reports Server (NTRS)

Dugala, Gina M.; Taylor, Linda M.; Kussmaul, Michael; Casciani, Michael; Brown, Gregory; Wiser, Joel

2017-01-01

Future NASA missions could include establishing Lunar or Martian base camps, exploring Jupiters moons and travelling beyond where generating power from sunlight may be limited. Radioisotope Power Systems (RPS) provide a dependable power source for missions where inadequate sunlight or operational requirements make other power systems impractical. Over the past decade, NASA Glenn Research Center (GRC) has been supporting the development of RPSs. The Advanced Stirling Radioisotope Generator (ASRG) utilized a pair of Advanced Stirling Convertors (ASC). While flight development of the ASRG has been cancelled, much of the technology and hardware continued development and testing to guide future activities. Specifically, a controller for the convertor(s) is an integral part of a Stirling-based RPS. For the ASRG design, the controller maintains stable operation of the convertors, regulates the alternating current produced by the linear alternator of the convertor, provides a specified direct current output voltage for the spacecraft, synchronizes the piston motion of the two convertors in order to minimize vibration as well as manage and maintain operation with a stable piston amplitude and hot end temperature. It not only provides power to the spacecraft but also must regulate convertor operation to avoid damage to internal components and maintain safe thermal conditions after fueling. Lockheed Martin Coherent Technologies has designed, developed and tested an Engineering Development Unit (EDU) Advanced Stirling Convertor Control Unit (ACU) to support this effort. GRC used the ACU EDU as part of its non-nuclear representation of a RPS which also consists of a pair of Dual Advanced Stirling Convertor Simulator (DASCS), and associated support equipment to perform a test in the Radioisotope Power Systems System Integration Laboratory (RSIL). The RSIL was designed and built to evaluate hardware utilizing RPS technology. The RSIL provides insight into the electrical interactions between as many as 3 radioisotope power generators, associated control strategies, and typical electric system loads. The first phase of testing included a DASCS which was developed by Johns Hopkins UniversityApplied Physics Laboratory and simulates the operation and electrical behavior of a pair of ASCs in real time via a combination of hardware and software. Testing included the following spacecraft electrical energy storage configurations: capacitive, battery, and supercapacitor. Testing of the DASCS and ACU in each energy storage configuration included simulation of a typical mission profile, and transient voltage and current data during load turn-on/turn-off. Testing for these devices also included the initiation of several system faults such as short circuits, electrical bus over-voltage, under-voltage and a dead bus recovery to restore normal power operations. The goal of this testing was to verify operation of the ACU(s) when connected to a spacecraft electrical bus.

Optical interconnection using polyimide waveguide for multichip module

NASA Astrophysics Data System (ADS)

Koyanagi, Mitsumasa

1996-01-01

We have developed a parallel processor system with 152 RISC processor chips specific for Monte-Carlo analysis. This system has the ring-bus architecture. The performance of several Gflops is expected in this system according to the computer simulation. However, it was revealed that the data transfer speed of the bus has to be increased more dramatically in order to further increase the performance. Then, we propose to introduce the optical interconnection into the parallel processor system to increase the data transfer speed of the buses. The double ring-bus architecture is employed in this new parallel processor system with optical interconnection. The free-space optical interconnection and the optical waveguide are used for the optical ring-bus. Thin polyimide film was used to form the optical waveguide. A relatively low propagation loss was achieved in the polyimide optical waveguide. In addition, it was confirmed that the propagation direction of signal light can be easily changed by using a micro-mirror.

The electrical performance of Ag Zn batteries for the Venus multi-probe mission

NASA Technical Reports Server (NTRS)

Palandati, C.

1975-01-01

An evaluation of 5 Ah and 21 Ah Silver-Zinc batteries was made to determine their suitability to meet the energy storage requirements of the bus vehicle, 3 small probes and large probe for the Venus multi-probe mission. The evaluation included a 4 Ah battery for the small probe, a 21 Ah battery for the large probe, one battery of each size for the bus vehicle power, a periodic cycling test on each size battery and a wet stand test of charged and discharged cells of both cell designs. The study on the probe batteries and bus vehicle batteries included both electrical and thermal simulation for the entire mission. The effects on silver migration and zinc penetration of the cellophane separators caused by the various test parameters were determined by visual and X-ray fluorescence analysis. The 5 Ah batteries supported the power requirements for the bus vehicle and small probe. The 21 Ah large probe battery supplied the required mission power. Both probe batteries delivered in excess of 132 percent of rated capacity at the completion of the mission simulation.

A computerized aircraft battery servicing facility

NASA Technical Reports Server (NTRS)

Glover, Richard D.

1992-01-01

The latest upgrade to the Aerospace Energy Systems Laboratory (AESL) is described. The AESL is a distributed digital system consisting of a central system and battery servicing stations connected by a high-speed serial data bus. The entire system is located in two adjoining rooms; the bus length is approximately 100 ft. Each battery station contains a digital processor, data acquisition, floppy diskette data storage, and operator interfaces. The operator initiates a servicing task and thereafter the battery station monitors the progress of the task and terminates it at the appropriate time. The central system provides data archives, manages the data bus, and provides a timeshare interface for multiple users. The system also hosts software production tools for the battery stations and the central system.

Transit bus stop pedestrian warning application : architecture and design : final report.

DOT National Transportation Integrated Search

2017-02-28

This document describes the Draft System Architecture and Design for the Transit Bus Stop Pedestrian Warning (TSPW) application including the design for the pedestrian detection system and DSRC radio to be deployed at transit stops and includes detai...

Digital Map Requirements For Automatic Vehicle Location

DOT National Transportation Integrated Search

1998-12-01

New Jersey Transit (NJT) is currently investigating acquisition of an automated vehicle locator (AVL) system. The purpose of the AVL system is to monitor the location of buses. Knowing the location of a bus enables the agency to manage the bus fleet ...

Sensor/Transducer Bus Alternatives for Space derived from Automotive Networks

NASA Astrophysics Data System (ADS)

Heyer, H.-V.

2004-06-01

Both automotive and space industry have major constraints concerning cable and harness. As in a satellite, the dry mass of the harness in the empty car is about 3.3% of the total car mass and the harness costs are about 12% of the total production cost. So a lot of new architectural communication and power distribution concepts are needed to reduce these drawbacks. One of the possible solutions is the use of distributed bus systems which contains in a decentralized topology busses such as CAN, TTCAN or FLEX-RAY for hard-real-time applications, MOST for fast video communication via optical fiber cabling and fire wire IEEE1394 as backbone.For the general purpose sensor/actuator tasks a simple robust one-wire bus has been defined, the Local Interconnect Network (LIN) bus. This bus is an open standard which is supported by several semiconductor manufactures. The bus was firstly introduced in 1999 and has now reached an acceptable maturity with version 2.0 turning out to be quite interesting as sensor / transducer bus for space applications.This presentation will focus on the LIN Bus and present an overview of that bus.

Research on Control Strategy of the Micro Grid’s Hybrid Energy System

NASA Astrophysics Data System (ADS)

Gao, Zi-jun; Li, Yang; Wang, Yan-ping; Zong, Ke-yong; Zhang, Jing

2018-03-01

This paper study the structure and operating characteristic of the hybrid energy system which is made of super-capacitor and battery. The system is controlled by strategy of bus voltage following. The bus voltage can change the state from swings to stable quickly when load mutation occurs in the micro grid. The transient impact also can be reduced by this way. The passage set up the model of energy system and make an analysis by the software named MATLAB/Simulink. At last, the passage proves the correctness and the effectiveness of the control strategy and draws a conclusion that the transient impact can be inhibited which occurs in the bus voltage of energy system.

A free ride? An analysis of the association of casino bus tours and problem gambling among older adults.

PubMed

van der Maas, Mark; Mann, Robert E; Matheson, Flora I; Turner, Nigel E; Hamilton, Hayley A; McCready, John

2017-12-01

Little research has examined the relationship between incentives used by gambling venues to attract customers and the experience of gambling-related harm. Organized and subsidized bus tours are a common example of such incentives. The aim of this study was to examine whether bus-tour patronage was associated with increased odds of problem gambling among older adults. This study also compared rates of bus-tour use by socio-demographic characteristics and gambling behaviours. Pearson's χ 2 tests and Mann-Whitney U-tests were applied for bivariate analyses. Multivariate generalized mixed-effects regression modelling was used to examine the relationship between bus-tour patronage and problem gambling while controlling for possible confounding factors. Seven gambling venues located in Central and Southwestern Ontario, Canada. A total of 1978 gambling venue patrons over the age of 55 years. Problem gambling as indicated by the Problem Gambling Severity Index, bus-tour patronage in the 12 months prior to the survey, spending per gambling visit and past-month slot machine participation. Regression analyses showed that bus-tour patronage was associated with higher odds of problem gambling [odds ratio (OR) = 1.71, confidence interval (CI) = 1.06, 2.76] after controlling for several demographic characteristics, type of gambling and gambling expenditures. Bivariate analyses showed past-year bus-tour patronage was associated with more frequent slot machine play (χ 2 = 48.16, P < 0.001), more past-year gambling venue visits (P < 0.001) and lower spending on gambling per casino visit (P < 0.001). Compared with non-patrons, bus tour patrons were more likely to be female (χ 2 = 21.92, P < 0.001), born outside Canada (χ 2 = 113.18, P < 0.001), above the age of 75 (χ 2 = 24.02, P < 0.001) and retired (χ 2 = 16.60, P < 0.001). When adjusting for potential confounders among older adults, using bus tours to access Canadian gambling venues is associated with increased risk of problem gambling. Bus-tour patrons are more likely to be female, born outside Canada and above the age of 75 years. © 2017 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

SunLine Test Drives Hydrogen Bus

DOT National Transportation Integrated Search

2003-08-01

SunLine collaborated with the U.S. Department of Energys (DOE) Hydrogen, Fuel Cells & Infrastructure Technologies (HFC&IT) Program on the evaluation of the 30-foot hybrid fuel cell bus that was developed by ThunderPower LLC, a joint venture by Tho...

Test Rack Development for Extended Operation of Advanced Stirling Convertors at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Dugala, Gina M.

2010-01-01

The U.S. Department of Energy, Lockheed Martin Space Systems Company, Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science missions. This generator will make use of free-piston Stirling convertors to achieve higher conversion efficiency than with currently available alternatives. One part of NASA GRC's support of ASRG development includes extended operation testing of Advanced Stirling Convertors (ASCs) developed by Sunpower Inc. and GRC. The ASC consists of a free-piston Stirling engine integrated with a linear alternator. NASA GRC has been building test facilities to support extended operation of the ASCs for several years. Operation of the convertors in the test facility provides convertor performance data over an extended period of time. One part of the test facility is the test rack, which provides a means for data collection, convertor control, and safe operation. Over the years, the test rack requirements have changed. The initial ASC test rack utilized an alternating-current (AC) bus for convertor control; the ASRG Engineering Unit (EU) test rack can operate with AC bus control or with an ASC Control Unit (ACU). A new test rack is being developed to support extended operation of the ASC-E2s with higher standards of documentation, component selection, and assembly practices. This paper discusses the differences among the ASC, ASRG EU, and ASC-E2 test racks.

Emissions of toxic pollutants from compressed natural gas and low sulfur diesel-fueled heavy-duty transit buses tested over multiple driving cycles.

PubMed

Kado, Norman Y; Okamoto, Robert A; Kuzmicky, Paul A; Kobayashi, Reiko; Ayala, Alberto; Gebel, Michael E; Rieger, Paul L; Maddox, Christine; Zafonte, Leo

2005-10-01

The number of heavy-duty vehicles using alternative fuels such as compressed natural gas (CNG) and new low-sulfur diesel fuel formulations and equipped with after-treatment devices are projected to increase. However, few peer-reviewed studies have characterized the emissions of particulate matter (PM) and other toxic compounds from these vehicles. In this study, chemical and biological analyses were used to characterize the identifiable toxic air pollutants emitted from both CNG and low-sulfur-diesel-fueled heavy-duty transit buses tested on a chassis dynamometer over three transient driving cycles and a steady-state cruise condition. The CNG bus had no after-treatment, and the diesel bus was tested first equipped with an oxidation catalyst (OC) and then with a catalyzed diesel particulate filter (DPF). Emissions were analyzed for PM, volatile organic compounds (VOCs; determined on-site), polycyclic aromatic hydrocarbons (PAHs), and mutagenic activity. The 2000 model year CNG-fueled vehicle had the highest emissions of 1,3-butadiene, benzene, and carbonyls (e.g., formaldehyde) of the three vehicle configurations tested in this study. The 1998 model year diesel bus equipped with an OC and fueled with low-sulfur diesel had the highest emission rates of PM and PAHs. The highest specific mutagenic activities (revertants/microg PM, or potency) and the highest mutagen emission rates (revertants/mi) were from the CNG bus in strain TA98 tested over the New York Bus (NYB) driving cycle. The 1998 model year diesel bus with DPF had the lowest VOCs, PAH, and mutagenic activity emission. In general, the NYB driving cycle had the highest emission rates (g/mi), and the Urban Dynamometer Driving Schedule (UDDS) had the lowest emission rates for all toxics tested over the three transient test cycles investigated. Also, transient emissions were, in general, higher than steady-state emissions. The emissions of toxic compounds from an in-use CNG transit bus (without an oxidation catalyst) and from a vehicle fueled with low-sulfur diesel fuel (equipped with DPF) were lower than from the low-sulfur diesel fueled vehicle equipped with OC. All vehicle configurations had generally lower emissions of toxics than an uncontrolled diesel engine. Tunnel backgrounds (measurements without the vehicle running) were measured throughout this study and were helpful in determining the incremental increase in pollutant emissions. Also, the on-site determination of VOCs, especially 1,3-butadiene, helped minimize measurement losses due to sample degradation after collection.

Position reporting system using small satellites

NASA Technical Reports Server (NTRS)

Pavesi, B.; Rondinelli, G.; Graziani, F.

1990-01-01

A system able to provide position reporting and monitoring services for mobile applications represents a natural complement to the Global Positioning System (GPS) navigation system. The system architecture is defined on the basis of the communications requirements derived by user needs, allowing maximum flexibility in the use of channel capacity, and a very simple and low cost terminal. The payload is sketched, outlining the block modularity and the use of qualified hardware. The global system capacity is also derived. The spacecraft characteristics are defined on the basis of the payload requirements. A small bus optimized for Ariane IV, Delta II vehicles and based on the modularity concept is presented. The design takes full advantage of each launcher with a common basic bus or bus elements for a mass production.

Wireless GPS fleet tracking system at the University of Albany.

DOT National Transportation Integrated Search

2014-07-01

This report provides an overview of the project undertaken at the University at Albany to make alternative transportation a more : viable option by implementing a GPS Tracking System on the University bus fleet and broadcasting the bus locations to c...

KSC-99pp1251

NASA Image and Video Library

1999-10-25

KSC workers, with Center Director Roy Bridges (at right next to bus), head for the open door of the Zero Emissions (ZE) transit bus and a ride around the center. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product "exhaust" from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available to employees for viewing and a ride, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

NASA Technical Reports Server (NTRS)

1999-01-01

KSC employees, along with Center Director Roy Bridges (second from left), view the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

NASA Technical Reports Server (NTRS)

1999-01-01

On view in front of the Headquarters Building, the Zero Emissions (ZE) transit bus attracts an interested group of employees, including Center Director Roy Bridges (second from left in foreground). Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC

NASA Technical Reports Server (NTRS)

1999-01-01

In front of the Headquarters Building at KSC, Center Director Roy Bridges (left) looks at the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by- product 'exhaust' from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27.

Experimental demonstration of 1.5Hz passive isolation system for precision optical payloads

NASA Astrophysics Data System (ADS)

Guan, Xin; Wang, Guang-yuan; Cao, Dong-jing; Tang, Shao-fan; Chen, Xiang; Liang, Lu; Zheng, Gang-tie

2017-11-01

The ground resolution of remote sensing satellite has been raised from hundreds of meters to less than one meter in recent few decades. As a result, the precision optical payload becomes more and more sensitive to structure vibrations of satellite buses. Although these vibrations generally have extremely low magnitude, they can result in significant image quality degradation to an optical payload. The suggestion of using vibration isolators to isolate payload from the satellite bus has been put forward in 1980s'[1]. Recently, WorldView-2 achieved its perfect image quality via using a set of low frequency isolators[2]. Recently, some of the optical payload manufacturers begin to provide vibration isolators as standard parts together with their main products . During the prototype testing of an earth resource satellite, the image of the optical payload was found to jitter for 5 10 pixels due to disturbances transmitted from the satellite bus structure. Test results indicated that the acceleration level of the vibration was of mG magnitude. To solve the problem, a highly sensitive vibration isolation system was developed to reduce the transmission of disturbances. Integrated isolation performance tests showed that the image jitter can be decreased to below 0.3 pixels.

Multisite Testing of the Discrete Address Beacon System (DABS).

DTIC Science & Technology

1981-07-01

downlink messages from an airborne distributed computer system containing , transponder in addition to performing 36 minicomputers, most of which are...the lockout function. organized into groups (or ensembles) of four computers interfaced to a local Each sensor may provide surveillance and data bus...position and velocity. Depending upon computer subsystem, which monitors the means used for scenario generation, in real time all communication and aircraft

Bus--carpool FWY lanes in San Francisco area

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

Newman, L.

1976-11-01

The California Department of Transportation is studying ways to increase the use of the urban freeway systems that will accommodate the maximum number of people with the least delay and the maximum possible safety in a cost-effective way. This paper describes operational features of four different projects under way, namely: a contraflow bus lane; a part-time bus lane in the same direction and unseparated from normal traffic; a bus-carpool lane also in the same direction and unseparated from normal traffic; and a preferential access to a metered freeway. (MCW)

49 CFR 393.83 - Exhaust systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... combustible part of the motor vehicle. (b) No exhaust system shall discharge to the atmosphere at a location... gasoline engine shall discharge to the atmosphere at or within 6 inches forward of the rearmost part of the bus. (d) The exhaust system of a bus using fuels other than gasoline shall discharge to the atmosphere...

49 CFR 393.83 - Exhaust systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... combustible part of the motor vehicle. (b) No exhaust system shall discharge to the atmosphere at a location... gasoline engine shall discharge to the atmosphere at or within 6 inches forward of the rearmost part of the bus. (d) The exhaust system of a bus using fuels other than gasoline shall discharge to the atmosphere...

49 CFR 393.83 - Exhaust systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... combustible part of the motor vehicle. (b) No exhaust system shall discharge to the atmosphere at a location... gasoline engine shall discharge to the atmosphere at or within 6 inches forward of the rearmost part of the bus. (d) The exhaust system of a bus using fuels other than gasoline shall discharge to the atmosphere...

Assessment of the applicability of cooperative vehicle-highway automation systems (CVHAS) to bus transit and intermodal freight : case study feasibility analyses in the Metropolitan Chicago Region.

DOT National Transportation Integrated Search

2008-12-01

This report presents the results of its performance assessment of the feasibility of applying cooperative vehicle- highway automation systems (CVHAS) to bus transit and freight movements in the metropolitan Chicago area. : CVHAS are systems that prov...

The wheels on the bus go "buy buy buy": school bus advertising laws.

PubMed

Pomeranz, Jennifer L

2012-09-01

School buses, a practical necessity for millions of children, are at the center of new efforts to raise revenue. School bus advertising laws bring public health and commercialization concerns to the school setting. In doing so, they potentially expose school districts to First Amendment lawsuits. I examined various school bus advertising bills and laws. I reviewed First Amendment "forum analysis" as applied in the transit and school settings to clarify how this legal test may affect school districts subject to such laws. I have made recommendations for school districts to enact appropriate policies to ensure that such advertising does not undermine public health and to enable the districts to maintain control over their property.

49 CFR 571.207 - Standard No. 207; Seating systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... means the part of the seat that provides forward and rearward positioning of the seat bench and back... than a school bus; a passenger seat on a school bus with a GVWR greater than 4,536 kilograms (10,000 pounds); and, a passenger seat on a school bus with a GVWR less than or equal to 4,536 kg manufactured...

49 CFR 571.207 - Standard No. 207; Seating systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... means the part of the seat that provides forward and rearward positioning of the seat bench and back... than a school bus; a passenger seat on a school bus with a GVWR greater than 4,536 kilograms (10,000 pounds); and, a passenger seat on a school bus with a GVWR less than or equal to 4,536 kg manufactured...

49 CFR 571.207 - Standard No. 207; Seating systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... means the part of the seat that provides forward and rearward positioning of the seat bench and back... than a school bus; a passenger seat on a school bus with a GVWR greater than 4,536 kilograms (10,000 pounds); and, a passenger seat on a school bus with a GVWR less than or equal to 4,536 kg manufactured...

75 FR 27414 - Airworthiness Directives; Airbus A318, A319, A320, A321 Series Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

... occurrences of loss of the AC [alternating current] BUS 1 have been reported which led in some instances to the loss of the AC ESS [essential] BUS and DC [direct current] ESS BUS and connected systems. The... condition for the specified products. The MCAI states: Several occurrences of loss of the AC [alternating...

National Fuel Cell Bus Program: Accelerated Testing Evaluation Report and Appendices, Alameda-Contra Costa Transit District (AC Transit)

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

Chandler, K.; Eudy, L.

2009-01-01

This is an evaluation of hydrogen fuel cell transit buses operating at AC Transit in revenue service since March 20, 2006 compared to similar diesel buses operating from the same depot. This evaluation report includes results from November 2007 through October 2008. Evaluation results include implementation experience, fueling station operation, fuel cell bus operations at Golden Gate Transit, and evaluation results at AC Transit (bus usage, availability, fuel economy, maintenance costs, and roadcalls).

Objectification of Public Bus Stop's Pavement Surface Morphology

NASA Astrophysics Data System (ADS)

Decký, Martin; Kováč, Matúš; Mužík, Juraj; Mičechová, Lenka; Ďuriš, Lukáš

2018-06-01

The article deals with the road pavement surface morphology objectification in term of the surface unevenness degradation during the life cycle of bus stop pavements. The article presents the results of long-term rut depth measurements performed during 25 years on selected bus stops which were intended to determine correlation dependences of pavement rut depth on a number of design axles. The article also presents different methods for rut depth measurements including the straightedge test, Profilograph GE, TRIMBLE CX, and dynamic Road Scanner.

75 FR 23843 - Discretionary Bus and Bus Facilities Program

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-04

... transit facilities and equipment. d. For facilities, evidence of proposed project compliance with ``Green Building'' certification. 3. For transit asset management system projects: If asset management system...-New York, Administrator, Region 7-Kansas One Bowling Green, Room 429, New City, MO, 901 Locust Street...

Evaluation of transit operations : data applications of Tri-Met's automated bus dispatching system

DOT National Transportation Integrated Search

2001-02-01

This paper presents an analysis of operating performance for Tri-Met, the transit provider for the Portland, Oregon metropolitan area. The analysis draws on data recovered by Tri-Met's automated Bus Dispatching System (BDS) and focuses on two main su...

Annoyance evaluation and the effect of noise on the health of bus drivers.

PubMed

Bruno, Portela S; Marcos, Queiroga R; Amanda, Constantini; Paulo, Zannin H T

2013-01-01

In the present study, we evaluated annoyance and the effects of noise on the health of bus drivers. For that, 200 bus drivers from a public transport company participated in a cross-sectional study. Annoyance and effects on health was measured with analog scale: Sleep quality, occurrence of tinnitus, headache, irritation, and annoyance from bus engine, traffic, and passengers. Data of age and working time of bus drivers also were obtained. For noise exposure, LA eq was evaluated in 80 buses. Statistical analysis consisted of mean, standard deviation, minimum, and maximum, Kruskal-Wallis test with post-hoc Dunn, one-way ANOVA with post-hoc Tukey and Spearman's correlation coefficient. Results indicate three groups of bus drivers (not annoyed: (N.A.), a little annoyed (L.A.) and highly annoyed (H.A.)). The group H.A. was younger and with less working time in relation to others, with a significant difference only for age. Regarding sleep quality, there was no significant difference. For results on the occurrence of tinnitus, headache and irritation after work, group H.A. had significantly higher means. Result of annoyance to the bus engine was significantly higher in H.A. than in L.A. and N.A. Annoyance to traffic and passengers, no significant differences were found, but the highest results were found for L.A., followed by H.A. and N.A. Equivalent sound pressure level in buses was above of the limit for occupational comfort. It was concluded that bus drivers has considerable level of noise annoyance and some health effects are perceived. The noise is a factor discomfort ergonomic that may cause effects on health of bus drivers. This study aims to evaluate annoyance and the effects of noise on the health of bus drivers. Cross-sectional study with buses and bus drivers. For that, 200 bus drivers from a public transport company participated in a cross-sectional study. Annoyance and effects on health was measured with analog scale: Sleep quality, occurrence of tinnitus, headache, irritation and annoyance from bus engine, traffic, and passengers. Data of age and working time of bus drivers also were obtained. For noise exposure, LA eq was evaluated in 80 buses. Statistical analysis consisted of mean, standard deviation, minimum and maximum, Kruskal-Wallis test with post-hoc Dunn, one-way ANOVA with post-hoc Tukey and Spearman's correlation coefficient. Results indicate three groups of bus drivers (N.A., a L.A. and H.A.). The group H.A. was younger and with less working time in relation to others, with a significant difference only for age. Regarding sleep quality, there was no significant difference. For results on the occurrence of tinnitus, headache and irritation after work, group H.A. had significantly higher means. Result of annoyance to the bus engine was significantly higher in H.A. than in L.A. and N.A. Annoyance to traffic and passengers, no significant differences were found, but the highest results were found for L.A., followed by H.A. and N.A. Equivalent sound pressure level in buses was above of the limit for occupational comfort. It was concluded that bus drivers has considerable level of noise annoyance and some health effects are perceived.

Use of DFIWG for Improvement of Voltage Stability Condition of a Power System

NASA Astrophysics Data System (ADS)

Hazarika, Durlav; Das, Ranjay

2017-12-01

This paper describes a method for improvement of voltage stability condition of a multi-bus power system by regulating reactive power generation at a Doubly Fed Induction Wind Generator (DFIWG). For this purpose, sensitivity relation between changes in voltage stability index at a bus with respect to change in reactive power generation of the DFIWG is derived. This relation is used to determine the required amount of change in rotor current of the DFIWG to improve the voltage stability index of the bus.

High voltage bus and auxiliary heater control system for an electric or hybrid vehicle

DOEpatents

Murty, Balarama Vempaty

2000-01-01

A control system for an electric or hybrid electric vehicle includes a vehicle system controller and a control circuit having an electric immersion heater. The heater is electrically connected to the vehicle's high voltage bus and is thermally coupled to a coolant loop containing a heater core for the vehicle's climate control system. The system controller responds to cabin heat requests from the climate control system by generating a pulse width modulated signal that is used by the control circuit to operate the heater at a duty cycle appropriate for the amount of cabin heating requested. The control system also uses the heater to dissipate excess energy produced by an auxiliary power unit and to provide electric braking when regenerative braking is not desirable and manual braking is not necessary. The control system further utilizes the heater to provide a safe discharge of a bank of energy storage capacitors following disconnection of the battery or one of the high voltage connectors used to transmit high voltage operating power to the various vehicle systems. The control circuit includes a high voltage clamping circuit that monitors the voltage on the bus and operates the heater to clamp down the bus voltage when it exceeds a pre-selected maximum voltage. The control system can also be used to phase in operation of the heater when the bus voltage exceeds a lower threshold voltage and can be used to phase out the auxiliary power unit charging and regenerative braking when the battery becomes fully charged.

49 CFR 383.73 - State procedures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... endorsement knowledge tests; (iv) Allow only a group-specific passenger (P) and school bus (S) endorsement and... issuing a CLP or a CDL to a person the State must verify the name, date of birth, and Social Security... the CLP, Non-domiciled CLP, CDL or Non-domiciled CDL. (n) Computer system controls. The State must...

Reducing school bus/light-vehicle conflicts through connected vehicle communications : final report.

DOT National Transportation Integrated Search

2016-09-15

This project aimed to develop and test a concept for improving the safety of school bus transportation using connected vehicle technology. The project consisted of three key steps that led to a final road study: 1) conducting focus groups with light ...

Accessing Faith-Based Organizations Using Public Transportation.

PubMed

Lewinson, Terri; Maley, Olivia; Esnard, Ann-Margaret

2017-01-01

Nondriving aging adults are at risk of experiencing mobility barriers that inhibit access to important community resources for managing health and wellbeing. This multimethod study explores bus transportation experiences of older adults who live in extended stay hotels and use faith-based organizations to access resources. Interviews from 17 nondriving older adults were analyzed for perspectives about using faith-based organizations and residents' experiences navigating to faith-based organizations through available bus transportation in their communities. Residents described both favorable and unfavorable experiences when reaching out for help from faith-based organizations. Although they report reliance on faith-based organizations for a variety of resources, residents were challenged by an ineffective bus system that interfered with resource accessibility. Suggestions for improving bus transit systems and providing alternative, aging-friendly transportation options are discussed.

Time-recovering PCI-AER interface for bio-inspired spiking systems

NASA Astrophysics Data System (ADS)

Paz-Vicente, R.; Linares-Barranco, A.; Cascado, D.; Vicente, S.; Jimenez, G.; Civit, A.

2005-06-01

Address Event Representation (AER) is an emergent neuromorphic interchip communication protocol that allows for real-time virtual massive connectivity between huge number neurons located on different chips. By exploiting high speed digital communication circuits (with nano-seconds timings), synaptic neural connections can be time multiplexed, while neural activity signals (with mili-seconds timings) are sampled at low frequencies. Also, neurons generate 'events' according to their activity levels. More active neurons generate more events per unit time, and access the interchip communication channel more frequently, while neurons with low activity consume less communication bandwidth. When building multi-chip muti-layered AER systems it is absolutely necessary to have a computer interface that allows (a) to read AER interchip traffic into the computer and visualize it on screen, and (b) inject a sequence of events at some point of the AER structure. This is necessary for testing and debugging complex AER systems. This paper presents a PCI to AER interface, that dispatches a sequence of events received from the PCI bus with embedded timing information to establish when each event will be delivered. A set of specialized states machines has been introduced to recovery the possible time delays introduced by the asynchronous AER bus. On the input channel, the interface capture events assigning a timestamp and delivers them through the PCI bus to MATLAB applications. It has been implemented in real time hardware using VHDL and it has been tested in a PCI-AER board, developed by authors, that includes a Spartan II 200 FPGA. The demonstration hardware is currently capable to send and receive events at a peak rate of 8,3 Mev/sec, and a typical rate of 1 Mev/sec.

Characterisation of vibration input to flywheel used on urban bus

NASA Astrophysics Data System (ADS)

Wang, L.; Kanarachos, S.; Christensen, J.

2016-09-01

Vibration induced from road surface has an impact on the durability and reliability of electrical and mechanical components attached on the vehicle. There is little research published relevant to the durability assessment of a flywheel energy recovery system installed on city and district buses. Relevant international standards and legislations were reviewed and large discrepancy was found among them, in addition, there are no standards exclusively developed for kinetic energy recovery systems on vehicles. This paper describes the experimentation of assessment of road surface vibration input to the flywheel on a bus as obtained at the MIRA Proving Ground. Power density spectra have been developed based on the raw data obtained during the experimentation. Validation of this model will be carried out using accelerated life time tests that will be carried out on a shaker rig using an accumulated profile based on the theory of fatigue damage equivalence in time and frequency domain aligned with the model predictions.

The 30-cm ion thruster power processor

NASA Technical Reports Server (NTRS)

Herron, B. G.; Hopper, D. J.

1978-01-01

A power processor unit for powering and controlling the 30 cm Mercury Electron-Bombardment Ion Thruster was designed, fabricated, and tested. The unit uses a unique and highly efficient transistor bridge inverter power stage in its implementation. The system operated from a 200 to 400 V dc input power bus, provides 12 independently controllable and closely regulated dc power outputs, and has an overall power conditioning capacity of 3.5 kW. Protective circuitry was incorporated as an integral part of the design to assure failure-free operation during transient and steady-state load faults. The implemented unit demonstrated an electrical efficiency between 91.5 and 91.9 at its nominal rated load over the 200 to 400 V dc input bus range.

Bus rapid transit and development : policies and practices that affect development around transit.

DOT National Transportation Integrated Search

2009-12-01

The development of Bus Rapid Transit (BRT) systems is relatively recent in the United States, but several systems are in operation and more are advancing. There is a need for a more comprehensive understanding of the relationship between land use and...

Circuit for Communication Over Power Lines

NASA Technical Reports Server (NTRS)

Krasowski, Michael J.; Prokop, Normal F.; Greer, Lawrence C., III; Nappier, Jennifer

2011-01-01

Many distributed systems share common sensors and instruments along with a common power line supplying current to the system. A communication technique and circuit has been developed that allows for the simple inclusion of an instrument, sensor, or actuator node within any system containing a common power bus. Wherever power is available, a node can be added, which can then draw power for itself, its associated sensors, and actuators from the power bus all while communicating with other nodes on the power bus. The technique modulates a DC power bus through capacitive coupling using on-off keying (OOK), and receives and demodulates the signal from the DC power bus through the same capacitive coupling. The circuit acts as serial modem for the physical power line communication. The circuit and technique can be made of commercially available components or included in an application specific integrated circuit (ASIC) design, which allows for the circuit to be included in current designs with additional circuitry or embedded into new designs. This device and technique moves computational, sensing, and actuation abilities closer to the source, and allows for the networking of multiple similar nodes to each other and to a central processor. This technique also allows for reconfigurable systems by adding or removing nodes at any time. It can do so using nothing more than the in situ power wiring of the system.

Digital signal conditioning for flight test instrumentation

NASA Technical Reports Server (NTRS)

Bever, Glenn A.

1991-01-01

An introduction to digital measurement processes on aircraft is provided. Flight test instrumentation systems are rapidly evolving from analog-intensive to digital intensive systems, including the use of onboard digital computers. The topics include measurements that are digital in origin, as well as sampling, encoding, transmitting, and storing data. Particular emphasis is placed on modern avionic data bus architectures and what to be aware of when extracting data from them. Examples of data extraction techniques are given. Tradeoffs between digital logic families, trends in digital development, and design testing techniques are discussed. An introduction to digital filtering is also covered.

Land use impacts of bus rapid transit : phase II -- effects of BRT station proximity on property values along the Boston silver line Washington Street Corridor.

DOT National Transportation Integrated Search

2012-07-01

The development of Bus Rapid Transit (BRT) systems is relatively recent in the U.S.; however, several systems are operating and many : more are being planned. A comprehensive understanding of the relationship between land uses and BRT systems is need...

Performance Analysis of Trans-Jakarta Bus Suburban Service Move-Across Greater Jakarta

NASA Astrophysics Data System (ADS)

Tangkudung, ESW; Widyadayinta, C.

2018-03-01

Trans-Jakarta have developed their services scope as Suburban Service or Feeder move-across service that operate from greater Jakarta into Jakarta central vice versa. One of the route is Ciputat – Bundaran Hotel Indonesia (Tosari) and integrated with corridor 1 (one) and 8 (eight). This service is not travel on the exclusive lane or bus-way. Objective of Government Jakarta to provide this service is to decrease private car to enter the central of Jakarta. The objective of this study is to find the performance of the service. Survey have conducted static and dynamic on work day to get variable of travel time and delay, waiting time of passenger at the bus stop, headway and ridership of the bus. Service Standard Minimum of Trans-Jakarta have compared with the result of variable headway, travel speed, and waiting time at bus stop as concern of all the passengers. Analysis use correlation test method and linear regression model have done. The performance of Trans-Jakarta bus suburban service, based on travel speed indicator is fairly bad, only 8.1% of trip could comply with Minimum Service Standard. Bus performance based on the indicator of density in the bus is good, where all points are below the maximum limit i.e. 8 people/m2 at peak hour and 5 people/m2 at off-peak hour.

Emergence of criticality in the transportation passenger flow: scaling and renormalization in the Seoul bus system.

PubMed

Goh, Segun; Lee, Keumsook; Choi, Moo Young; Fortin, Jean-Yves

2014-01-01

Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare) bus stops are transformed into a (renormalized) "block stop" and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow.

Emergence of Criticality in the Transportation Passenger Flow: Scaling and Renormalization in the Seoul Bus System

PubMed Central

Goh, Segun; Lee, Keumsook; Choi, MooYoung; Fortin, Jean-Yves

2014-01-01

Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare) bus stops are transformed into a (renormalized) “block stop” and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow. PMID:24599221

Non-contact data access with direction identification for industrial differential serial bus

NASA Astrophysics Data System (ADS)

Xie, Kai; Li, Xiaoping; Zhang, Hanlu; Yang, Ming; Ye, Yinghao

2013-06-01

We propose a non-contact method for accessing data in industrial differential serial bus applications, which could serve as an effective and safe online testing and diagnosing tool. The data stream and the transmission direction are reconstructed simultaneously from the near-field emanations of a twisted pair, eliminating direct contact with the actual conductors, and avoiding damage to the insulation (only the outer sheathing is removed). A non-contact probe with the ability to sense electric and magnetic fields is presented, as are theories for data reconstruction, direction identification, and a circuit implementation. The prototype was built using inexpensive components and then tested on a standard RS-485 industrial serial bus. Experimental results verified the validity of the proposed scheme.

A novel symbiotic organisms search algorithm for congestion management in deregulated environment

NASA Astrophysics Data System (ADS)

Verma, Sumit; Saha, Subhodip; Mukherjee, V.

2017-01-01

In today's competitive electricity market, managing transmission congestion in deregulated power system has created challenges for independent system operators to operate the transmission lines reliably within the limits. This paper proposes a new meta-heuristic algorithm, called as symbiotic organisms search (SOS) algorithm, for congestion management (CM) problem in pool based electricity market by real power rescheduling of generators. Inspired by interactions among organisms in ecosystem, SOS algorithm is a recent population based algorithm which does not require any algorithm specific control parameters unlike other algorithms. Various security constraints such as load bus voltage and line loading are taken into account while dealing with the CM problem. In this paper, the proposed SOS algorithm is applied on modified IEEE 30- and 57-bus test power system for the solution of CM problem. The results, thus, obtained are compared to those reported in the recent state-of-the-art literature. The efficacy of the proposed SOS algorithm for obtaining the higher quality solution is also established.

A novel symbiotic organisms search algorithm for congestion management in deregulated environment

NASA Astrophysics Data System (ADS)

Verma, Sumit; Saha, Subhodip; Mukherjee, V.

2017-01-01

In today's competitive electricity market, managing transmission congestion in deregulated power system has created challenges for independent system operators to operate the transmission lines reliably within the limits. This paper proposes a new meta-heuristic algorithm, called as symbiotic organisms search (SOS) algorithm, for congestion management (CM) problem in pool-based electricity market by real power rescheduling of generators. Inspired by interactions among organisms in ecosystem, SOS algorithm is a recent population-based algorithm which does not require any algorithm specific control parameters unlike other algorithms. Various security constraints such as load bus voltage and line loading are taken into account while dealing with the CM problem. In this paper, the proposed SOS algorithm is applied on modified IEEE 30- and 57-bus test power system for the solution of CM problem. The results, thus, obtained are compared to those reported in the recent state-of-the-art literature. The efficacy of the proposed SOS algorithm for obtaining the higher quality solution is also established.

Solid state power controllers

NASA Technical Reports Server (NTRS)

Gibbs, R. S.

1974-01-01

Solid state power controllers (SSPC's) are to be considered for use as replacements of electromechanical relays and circuit breakers in future spacecraft and aircraft. They satisfy the combined function of both the relay and circuit breaker and can be remotely controlled by small signals, typically 10 mA, 5 to 28 v(dc). They have the advantage over conventional relay/circuit breaker systems in that they can be located near the utilization equipment and the primary ac or dc bus. The low level control, trip indication and status signals can be circuited by small gauge wire for control, computer interface, logic, electrical multiplexing, onboard testing, power management, and distribution purposes. This results in increased system versatility at appreciable weight saving and increased reliability. Conventional systems require the heavy gage load wiring and the control wiring to be routed from the bus to the load to other remote relay contacts, switches, sensors, etc. and to the circuit breaker located in the flight engineer's compartment for purposes of manual reset.

Optimum bus system and water transportation study : staff report to the Board of Directors of Marin County Transit District

DOT National Transportation Integrated Search

1969-08-01

Describes an optimum bus system replacing existing Greyhound service and designed primarily for the purpose of meeting commuter travel demands in the San Francisco-Marin corridor as well as intra-county travel, and mid-day and weekend trips between M...

Analysis, operation and maintenance of a fuel cell/battery series-hybrid bus for urban transit applications

NASA Astrophysics Data System (ADS)

Bubna, Piyush; Brunner, Doug; Gangloff, John J.; Advani, Suresh G.; Prasad, Ajay K.

The fuel cell hybrid bus (FCHB) program was initiated at the University of Delaware in 2005 to demonstrate the viability of fuel cell vehicles for transit applications and to conduct research and development to facilitate the path towards their eventual commercialization. Unlike other fuel cell bus programs, the University of Delaware's FCHB design features a battery-heavy hybrid which offers multiple advantages in terms of cost, performance and durability. The current fuel cell hybrid bus is driven on a regular transit route at the University of Delaware. The paper describes the baseline specifications of the bus with a focus on the fuel cell and the balance of plant. The fuel cell/battery series-hybrid design is well suited for urban transit routes and provides key operational advantages such as hydrogen fuel economy, efficient use of the fuel cell for battery recharging, and regenerative braking. The bus is equipped with a variety of sensors including a custom-designed cell voltage monitoring system which provide a good understanding of bus performance under normal operation. Real-time data collection and analysis have yielded key insights for fuel cell bus design optimization. Results presented here illustrate the complex flow of energy within the various subsystems of the fuel cell hybrid bus. A description of maintenance events has been included to highlight the issues that arise during general operation. The paper also describes several modifications that will facilitate design improvements in future versions of the bus. Overall, the fuel cell hybrid bus demonstrates the viability of fuel cells for urban transit applications in real world conditions.

A high-speed fiber optic data bus for local data communications

NASA Astrophysics Data System (ADS)

Porter, D. R.; Couch, P. R.; Schelin, J. W.

1983-04-01

A 100 Mbit/s fiber optic data bus is described which is capable of inter-connecting up to 16 terminals by means of a passive optical star coupler for terminal separation distance of up to 2 km. The system shows substantial performance margins and a BER of less than 10 to the -10th. Descriptions are also given of techniques for rapid laser stabilization, clock recovery, and the detection of bursty data over a wide dynamic range. The dynamic time slot allocations (DTSA) access protocol, which makes efficient use of the data bus under heavy bus loading conditions, is defined.

Intelligent Urban Public Transportation for Accessibility Dedicated to People with Disabilities

PubMed Central

Zhou, Haiying; Hou, Kun-Mean; Zuo, Decheng; Li, Jian

2012-01-01

The traditional urban public transport system generally cannot provide an effective access service for people with disabilities, especially for disabled, wheelchair and blind (DWB) passengers. In this paper, based on advanced information & communication technologies (ICT) and green technologies (GT) concepts, a dedicated public urban transportation service access system named Mobi+ has been introduced, which facilitates the mobility of DWB passengers. The Mobi+ project consists of three subsystems: a wireless communication subsystem, which provides the data exchange and network connection services between buses and stations in the complex urban environments; the bus subsystem, which provides the DWB class detection & bus arrival notification services; and the station subsystem, which implements the urban environmental surveillance & bus auxiliary access services. The Mobi+ card that supports multi-microcontroller multi-transceiver adopts the fault-tolerant component-based hardware architecture, in which the dedicated embedded system software, i.e., operating system micro-kernel and wireless protocol, has been integrated. The dedicated Mobi+ embedded system provides the fault-tolerant resource awareness communication and scheduling mechanism to ensure the reliability in data exchange and service provision. At present, the Mobi+ system has been implemented on the buses and stations of line ‘2’ in the city of Clermont-Ferrand (France). The experiential results show that, on one hand the Mobi+ prototype system reaches the design expectations and provides an effective urban bus access service for people with disabilities; on the other hand the Mobi+ system is easily to deploy in the buses and at bus stations thanks to its low energy consumption and small form factor. PMID:23112622

Intelligent urban public transportation for accessibility dedicated to people with disabilities.

PubMed

Zhou, Haiying; Hou, Kun-Mean; Zuo, Decheng; Li, Jian

2012-01-01

The traditional urban public transport system generally cannot provide an effective access service for people with disabilities, especially for disabled, wheelchair and blind (DWB) passengers. In this paper, based on advanced information & communication technologies (ICT) and green technologies (GT) concepts, a dedicated public urban transportation service access system named Mobi+ has been introduced, which facilitates the mobility of DWB passengers. The Mobi+ project consists of three subsystems: a wireless communication subsystem, which provides the data exchange and network connection services between buses and stations in the complex urban environments; the bus subsystem, which provides the DWB class detection & bus arrival notification services; and the station subsystem, which implements the urban environmental surveillance & bus auxiliary access services. The Mobi+ card that supports multi-microcontroller multi-transceiver adopts the fault-tolerant component-based hardware architecture, in which the dedicated embedded system software, i.e., operating system micro-kernel and wireless protocol, has been integrated. The dedicated Mobi+ embedded system provides the fault-tolerant resource awareness communication and scheduling mechanism to ensure the reliability in data exchange and service provision. At present, the Mobi+ system has been implemented on the buses and stations of line '2' in the city of Clermont-Ferrand (France). The experiential results show that, on one hand the Mobi+ prototype system reaches the design expectations and provides an effective urban bus access service for people with disabilities; on the other hand the Mobi+ system is easily to deploy in the buses and at bus stations thanks to its low energy consumption and small form factor.

Characterisation of an urban bus network for environmental purposes.

PubMed

André, Michel; Villanova, André

2004-12-01

Since pollutant emissions are closely related to the operating conditions of vehicles, their evaluation usually involves studying these operating conditions (through bus instrumentation and monitoring under actual operation), the design of representative driving or engine test cycles and the measurement of pollutant emissions. A preliminary characterisation of the routes on a bus network should make it possible to identify typical routes, the driving conditions and pollutant emissions of which are then studied. Two approaches are envisaged and applied to the Paris area, for which a wealth of information is available, which should be transferable to other bus networks. Both approaches are based on factorial analysis and automatic clustering, to allow optimum description and the identification of a pertinent typology of the bus routes in several classes. The first attempt at characterisation is based on statistics relating to bus operations: route characteristics (length, dedicated bus lanes, number of stops, location of stops: schools, tourist sites, hospitals, railways or underground stations), travel time, commercial speed, annual statistics (number of passengers, number of vehicles per hour, total kilometres), the irregularity of travel (variation of travel times, injuries, congestion.), as well as information on the problems encountered (congestion, distribution of the passenger load, junctions, bends). A second approach is based on the analysis of the "urban context" in which buses are driven. Population, employment, housing, road network, traffic and places that generate or disturb traffic (schools, railway stations, shopping areas, etc.) are calculated for the Ile de France region, by cells of 100 x 100 m, and collected in a geographical information system (GIS). Statistical analyses enable a typology of these urban cells to be established, the main parameters being density, type of housing, road types and traffic levels. The bus routes are then analysed according to their itineraries across these typical areas (distances travelled in each type of area) using a similar approach. A comparison of the typologies obtained from operational data and from urban data highlights the advantages and disadvantages of the two approaches. The first result from these typologies is the selection of routes which are representative of the different classes, in order to instrument buses and record driving patterns. This method should also make it possible to link driving conditions and urban characteristics, and then to allocate pollutant emission factors to given geographical situations, in particular, in the context of emission inventories or impact studies.

Airborne Electro-Mechanical Actuator Test Stand for Development of Prognostic Health Management Systems

DTIC Science & Technology

2010-10-01

based on a pre-defined UH-60 data format, then also computes the load and position profile information. File Profile Interface In order to test the...of the data set. Figure 13 shows a typical motion profile executed over a period of about twenty minutes. Figure 14 shows the desired ( computed ...flight. The stand is connected to the aircraft data bus and the motion profiles for the test actuators, as well as the load applied to them, are

Characterizing the range of children's air pollutant exposure during school bus commutes.

PubMed

Sabin, Lisa D; Behrentz, Eduardo; Winer, Arthur M; Jeong, Seong; Fitz, Dennis R; Pankratz, David V; Colome, Steven D; Fruin, Scott A

2005-09-01

Real-time and integrated measurements of gaseous and particulate pollutants were conducted inside five conventional diesel school buses, a diesel bus with a particulate trap, and a bus powered by compressed natural gas (CNG) to determine the range of children's exposures during school bus commutes and conditions leading to high exposures. Measurements were made during 24 morning and afternoon commutes on two Los Angeles Unified School District bus routes from South to West Los Angeles, with seven additional runs on a rural/suburban route, and three runs to test the effect of window position. For these commutes, the mean concentrations of diesel vehicle-related pollutants ranged from 0.9 to 19 microg/m(3) for black carbon, 23 to 400 ng/m(3) for particle-bound polycyclic aromatic hydrocarbon (PB-PAH), and 64 to 220 microg/m(3) for NO(2). Concentrations of benzene and formaldehyde ranged from 0.1 to 11 microg/m(3) and 0.3 to 5 microg/m(3), respectively. The highest real-time concentrations of black carbon, PB-PAH and NO(2) inside the buses were 52 microg/m(3), 2000 ng/m(3), and 370 microg/m(3), respectively. These pollutants were significantly higher inside conventional diesel buses compared to the CNG bus, although formaldehyde concentrations were higher inside the CNG bus. Mean black carbon, PB-PAH, benzene and formaldehyde concentrations were higher when the windows were closed, compared with partially open, in part, due to intrusion of the bus's own exhaust into the bus cabin, as demonstrated through the use of a tracer gas added to each bus's exhaust. These same pollutants tended to be higher on urban routes compared to the rural/suburban route, and substantially higher inside the bus cabins compared to ambient measurements. Mean concentrations of pollutants with substantial secondary formation, such as PM(2.5), showed smaller differences between open and closed window conditions and between bus routes. Type of bus, traffic congestion levels, and encounters with other diesel vehicles contributed to high exposure variability between runs.

The Wheels on the Bus Go “Buy Buy Buy”: School Bus Advertising Laws

PubMed Central

2012-01-01

School buses, a practical necessity for millions of children, are at the center of new efforts to raise revenue. School bus advertising laws bring public health and commercialization concerns to the school setting. In doing so, they potentially expose school districts to First Amendment lawsuits. I examined various school bus advertising bills and laws. I reviewed First Amendment “forum analysis” as applied in the transit and school settings to clarify how this legal test may affect school districts subject to such laws. I have made recommendations for school districts to enact appropriate policies to ensure that such advertising does not undermine public health and to enable the districts to maintain control over their property. PMID:22742065

[Development and evaluation of a small group-based cardiocerebrovascular disease prevention education program for male bus drivers].

PubMed

Kim, Eun Young; Hwang, Seon Young

2012-06-01

This study was conducted to examine effects of a small group-based cardiocerebrovascular disease (CVD) prevention education program on knowledge, stage of change and health behavior among male bus drivers with CVD risk factors. A non-equivalent control group pretest-posttest design was used. Participants were 68 male bus drivers recruited from two urban bus companies. Participants from the two groups were selected by matching age, education and risk factors. Experimental group (n=34) received a small group-based CVD prevention education program 8 times over 6 weeks and 3 times through telephone interviews at 2-week intervals. Data were collected between December, 2010 and March, 2011, and were analyzed using chi-square test, t-test, and repeated measure analysis of variance with SPSS/Win18.0. Experimental group showed significantly higher scores in CVD prevention knowledge (p<.001) and health behavior (p<.001) at 6 and 12 weeks after intervention. Participants in pre-contemplation and contemplation stages made progress to contemplation and action. This was significantly better at 6 and 12 weeks after intervention (p<.001). Results suggest that small group-based education programs for CVD prevention are effective in increasing knowledge, stage of change, and health behavior to prevent CVD among male bus drivers with CVD risk.

Exact and Metaheuristic Approaches for a Bi-Objective School Bus Scheduling Problem.

PubMed

Chen, Xiaopan; Kong, Yunfeng; Dang, Lanxue; Hou, Yane; Ye, Xinyue

2015-01-01

As a class of hard combinatorial optimization problems, the school bus routing problem has received considerable attention in the last decades. For a multi-school system, given the bus trips for each school, the school bus scheduling problem aims at optimizing bus schedules to serve all the trips within the school time windows. In this paper, we propose two approaches for solving the bi-objective school bus scheduling problem: an exact method of mixed integer programming (MIP) and a metaheuristic method which combines simulated annealing with local search. We develop MIP formulations for homogenous and heterogeneous fleet problems respectively and solve the models by MIP solver CPLEX. The bus type-based formulation for heterogeneous fleet problem reduces the model complexity in terms of the number of decision variables and constraints. The metaheuristic method is a two-stage framework for minimizing the number of buses to be used as well as the total travel distance of buses. We evaluate the proposed MIP and the metaheuristic method on two benchmark datasets, showing that on both instances, our metaheuristic method significantly outperforms the respective state-of-the-art methods.

Passenger bus industry weather information application.

DOT National Transportation Integrated Search

2011-03-21

Adverse weather significantly affects the United States national transportation system, including commercial companies that rely on highways to support their enterprises. The Passenger Bus (Motorcoach) Industry (PBI) is one such affected user whose o...

High-Voltage, Low-Power BNC Feedthrough Terminator

NASA Technical Reports Server (NTRS)

Bearden, Douglas

2012-01-01

This innovation is a high-voltage, lowpower BNC (Bayonet Neill-Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant. The Space Shuttle Program had a requirement to measure voltage transients on the orbiter bus through the Ground Lightning Measurement System (GLMS). This measurement has a bandwidth requirement of 1 MHz. The GLMS voltage measurement is connected to the orbiter through a DC panel. The DC panel is connected to the bus through a nonuniform cable that is approximately 75 ft (approximately equal to 23 m) long. A 15-ft (approximately equal to 5-m), 50-ohm triaxial cable is connected between the DC panel and the digitizer. Based on calculations and simulations, cable resonances and reflections due to mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. A voltage divider at the DC panel, and terminating the 50-ohm cable properly, would eliminate this issue. Due to implementation issues, an alternative design was needed to terminate the cable properly without the use of a voltage divider. Analysis shows how the cable resonances and reflections due to the mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. After simulating a dampening circuit located at the digitizer, simulations were performed to show how the cable resonances were dampened and the accuracy was improved significantly. Test cables built to verify simulations were accurate. Since the dampening circuit is low power, it can be packaged in a BNC feedthrough.

Design of limited-stop service based on the degree of unbalance of passenger demand

PubMed Central

2018-01-01

This paper presents a limited-stop service for a bus fleet to meet the unbalanced demand of passengers on a bus route and to improve the transit service of the bus route. This strategy includes two parts: a degree assessment of unbalanced passenger demand and an optimization of the limited-stop service. The degree assessment of unbalanced passenger demand, which is based on the different passenger demand between stations and the unbalance of passengers within the station, is used to judge whether implementing the limited-stop service is necessary for a bus route. The optimization of limited-stop service considers the influence of stop skipping action and bus capacity on the left-over passengers to determine the proper skipping stations for the bus fleet serving the entire route by minimizing both the waiting time and in-vehicle time of passengers and the running time of vehicles. A solution algorithm based on genetic algorithm is also presented to evaluate the degree of unbalanced passenger demand and optimize the limited-stop scheme. Then, the proper strategy is tested on a bus route in Changchun city of China. The threshold of degree assessment of unbalanced passenger demand can be calibrated and adapted to different passenger demands. PMID:29505585

Design of limited-stop service based on the degree of unbalance of passenger demand.

PubMed

Zhang, Hu; Zhao, Shuzhi; Liu, Huasheng; Liang, Shidong

2018-01-01

This paper presents a limited-stop service for a bus fleet to meet the unbalanced demand of passengers on a bus route and to improve the transit service of the bus route. This strategy includes two parts: a degree assessment of unbalanced passenger demand and an optimization of the limited-stop service. The degree assessment of unbalanced passenger demand, which is based on the different passenger demand between stations and the unbalance of passengers within the station, is used to judge whether implementing the limited-stop service is necessary for a bus route. The optimization of limited-stop service considers the influence of stop skipping action and bus capacity on the left-over passengers to determine the proper skipping stations for the bus fleet serving the entire route by minimizing both the waiting time and in-vehicle time of passengers and the running time of vehicles. A solution algorithm based on genetic algorithm is also presented to evaluate the degree of unbalanced passenger demand and optimize the limited-stop scheme. Then, the proper strategy is tested on a bus route in Changchun city of China. The threshold of degree assessment of unbalanced passenger demand can be calibrated and adapted to different passenger demands.

Architecting Service-Oriented Systems

DTIC Science & Technology

2011-08-01

Abstract Service orientation is an approach to software systems development that has become a popular way to implement distributed, loosely coupled...runtime. The later you defer binding the more flexibility service providers and service consumers have to develop their software systems independently...Enterprise Service Bus An Enterprise Service Bus (ESB) is a software pattern that can be part of a SOA infrastructure and acts as an intermediary

AIDS is an exception to bus system's offer of lower fares.

PubMed

1997-05-02

The American Civil Liberties Union (ACLU) sued the Metro Link bus system in Rock Island, IL on behalf of [name removed]. The suit claims that the bus system explicitly excludes people with AIDS from a reduced-rate fare program for riders with disabilities. Currently, Metro Link offers a discount to senior citizens or people with disabilities who have documentation. The application for the discount specifically rules out people whose sole disability is AIDS. [Name removed] asked Metro Link to eliminate the exclusion. When the request was refused, the ACLU sued, alleging a violation of the Americans with Disabilities Act (ADA), the Rehabilitation Act, and [name removed]'s constitutional right to equal protection under the law.

KSC-99pp1248

NASA Image and Video Library

1999-10-25

In front of the Headquarters Building at KSC, Center Director Roy Bridges (left) looks at the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product "exhaust" from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27

KSC-99pp1249

NASA Image and Video Library

1999-10-25

KSC employees, along with Center Director Roy Bridges (second from left), view the hydrogen-oxygen driven engine powering a Zero Emissions (ZE) transit bus. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product "exhaust" from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27

KSC-99pp1253

NASA Image and Video Library

1999-10-25

The Zero Emissions (ZE) transit bus passes a mock-up orbiter named Explorer on a trek through the KSC Visitor Complex. Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product "exhaust" from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. The ZE bus is being used on tour routes at the KSC Visitor Complex for two days to introduce the public to the concept

Fast global orbit feedback system in PLS-II

NASA Astrophysics Data System (ADS)

Lee, J.; Kim, C.; Kim, J. M.; Kim, K. R.; Lee, E. H.; Lee, J. W.; Lee, T. Y.; Park, C. D.; Shin, S.; Yoon, J. C.; Cho, W. S.; Park, G. S.; Kim, S. C.

2016-12-01

The transverse position of the electron beam in the Pohang Light Source-II is stabilized by the global orbit feedback system. A slow orbit feedback system has been operating at 2 Hz, and a fast orbit feedback (FOFB) system at 813 Hz was installed recently. This FOFB system consists of 96 electron-beam-position monitors, 48 horizontal fast correctors, 48 vertical fast correctors and Versa Module Europa bus control system. We present the design and implementation of the FOFB system and its test result. Simulation analysis is presented and future improvements are suggested.

Preliminary Investigation of Workload on Intrastate Bus Traffic Controllers

NASA Astrophysics Data System (ADS)

Yen Bin, Teo; Azlis-Sani, Jalil; Nur Annuar Mohd Yunos, Muhammad; Ismail, S. M. Sabri S. M.; Tajedi, Noor Aqilah Ahmad

2016-11-01

The daily routine of bus traffic controller which involves high mental processes would have a direct impact on the level of workload. To date, the level of workload on the bus traffic controllers in Malaysia is relatively unknown. Excessive workload on bus traffic controllers would affect the control and efficiency of the system. This paper served to study the workload on bus traffic controllers and justify the needs to conduct further detailed research on this field. The objectives of this research are to identify the level of workload on the intrastate bus traffic controllers. Based on the results, recommendations will be proposed for improvements and future studies. The level of workload for the bus traffic controllers is quantified using questionnaire adapted from NASA TLX. Interview sessions were conducted for validation of workload. Sixteen respondents were involved and it was found that the average level of workload based on NASA TLX was 6.91. It was found that workload is not affected by gender and marital status. This study also showed that the level of workload and working experience of bus traffic controllers has a strong positive linear relationship. This study would serve as a guidance and reference related to this field. Since this study is a preliminary investigation, further detailed studies could be conducted to obtain a better comprehension regarding the bus traffic controllers.

Foothill Transit Electric Bus Testing | Transportation Research | NREL

Science.gov Websites

, this study aims to improve understanding of the overall usage and effectiveness of fast-charge electric well. The electric buses under study were Proterra EcoRide BE35 transit buses with eight 368V lithium Systems Technology Simulator, or FASTSim, to study the impact of route selection and other vehicle

Hybrid Electric Transit Bus Testing | Transportation Research | NREL

Science.gov Websites

this study are featured in the Long Beach Transit: Two-Year Evaluation of Gasoline-Electric Hybrid manufactured by Orion Industries with BAE propulsion systems. The results of this study are featured in the In power units. The results of this study are featured in the Ebus Hybrid Electric Buses and Trolleys case

The AI Bus architecture for distributed knowledge-based systems

NASA Technical Reports Server (NTRS)

Schultz, Roger D.; Stobie, Iain

1991-01-01

The AI Bus architecture is layered, distributed object oriented framework developed to support the requirements of advanced technology programs for an order of magnitude improvement in software costs. The consequent need for highly autonomous computer systems, adaptable to new technology advances over a long lifespan, led to the design of an open architecture and toolbox for building large scale, robust, production quality systems. The AI Bus accommodates a mix of knowledge based and conventional components, running on heterogeneous, distributed real world and testbed environment. The concepts and design is described of the AI Bus architecture and its current implementation status as a Unix C++ library or reusable objects. Each high level semiautonomous agent process consists of a number of knowledge sources together with interagent communication mechanisms based on shared blackboards and message passing acquaintances. Standard interfaces and protocols are followed for combining and validating subsystems. Dynamic probes or demons provide an event driven means for providing active objects with shared access to resources, and each other, while not violating their security.

A Comparative Study of Discovery Learning Scientific Community Laboratories and Traditional Laboratories in Physics at an Independent University, Florida, U. S

NASA Astrophysics Data System (ADS)

Reinhard, Karl E.

Electric power is fully interwoven into the fabric of American life. Its loss for extended periods has profound impacts upon public safety, health and welfare. The power system has been termed the most complex machine built by man. Not surprisingly, the measures to address the range of power system downtime causes are as diverse as the causes themselves. One important arc of effort is providing power system operators with full knowledge of the system's operating state, timely warning when changing conditions threaten system stability, and tools guiding control actions to maintain stable operations. This research is motivated, in part, by the need to explore opportunities for leveraging nascent synchrophasor data streams against known power system stability challenges. Over the past half-decade, power system operators have aggressively installed large networks of phasor measurement units (PMUs) and phasor data concentrators (PDCs) across the United States and Canada. Today, the synchrophasor data network has reached a state of maturity that opens the door to useful application. This dissertation investigates power system stability along three lines of effort. The first two efforts address steady-state power system stability--specifically methods for assessing system vulnerabilities arising from the phase angle difference between two buses connected by a transmission line. The third effort investigates the information that can be gleaned from synchrophasor measurements during a system's dynamic system response to changing system conditions. The first line of investigation extends steady-state distribution factor theory. Distribution factors are computed from a known non-linear power system load flow solution. They provide a computationally light method for estimating new system conditions under different operating circumstances. Distribution factors are extremely useful for very rapidly screening the impact of unexpected changes in power system configuration--e.g. a transmission line dropping out of service due to environmental conditions. The Line Outage Angle Factor (LOAF) developed herein provides a method for fast computation of bus voltage angle changes after a line outage. The Line Outage Generator Factor (LOGF) modifies the simulated circuit topology to include synchronous machine transient reactances, enabling rapid screening of operating states in which line opening (or re-closure) risks damaging equipment. The LOAF and LOGF provide promising results in MATLAB simulation of the Western System Coordinating Council 3-Machine, 9-Bus System. The second investigative line seeks to develop a Thevenin equivalent model to be used in tandem with synchrophasor data streams to provide real-time bus angle difference information for buses connected by a transmission line. The appeal is that real-time bus angle difference information could be computed on-site and very rapidly--and significantly, independent of other network bus measurements. The results show that developing a Thevenin equivalent that provides a useful angle difference measure often works well on paper, but is challenging using actual synchrophasor data. Efforts to develop a Thevenin equivalent using Monte Carlo methods show promise, but require further investigation. The third line of effort shifts to investigate the useful information that a PMU can produce during a power system disturbance event. A synchrophasor is defined at a specific frequency, i.e. the system steady-state operating frequency. Thus a PMU produces a data stream recording power system changes progressing slower than the nominal system frequency; consequently, this is an "off-label" synchrophasor data application. The test system is a generator with electrical and mechanical controls connected by a pair of identical transmission lines to an infinite bus. The synchronous generator is modeled as a three-damper-winding synchronous machine. A MATLAB simulation was written to simulate both the full 14 dynamic state and the reduced order 11 dynamic state system models. A Real-Time Digital Simulator (RTDS) simulation emulating the test system provides the capability to produce real-time analog generator terminal waveforms to be sampled by a commercial off-the-shelf PMU to produce synchrophasor data. We find that the RTDS generated synchrophasor data stream is similar to the MATLAB reduced order model voltage and current generator terminal data in the dqo reference frame--reflecting parallel, but distinct, filtering processes.

Electrical Design and Evaluation of Asynchronous Serial Bus Communication Network of 48 Sensor Platform LSIs with Single-Ended I/O for Integrated MEMS-LSI Sensors.

PubMed

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Muroyama, Masanori

2018-01-15

For installing many sensors in a limited space with a limited computing resource, the digitization of the sensor output at the site of sensation has advantages such as a small amount of wiring, low signal interference and high scalability. For this purpose, we have developed a dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) (referred to as "sensor platform LSI") for bus-networked Micro-Electro-Mechanical-Systems (MEMS)-LSI integrated sensors. In this LSI, collision avoidance, adaptation and event-driven functions are simply implemented to relieve data collision and congestion in asynchronous serial bus communication. In this study, we developed a network system with 48 sensor platform LSIs based on Printed Circuit Board (PCB) in a backbone bus topology with the bus length being 2.4 m. We evaluated the serial communication performance when 48 LSIs operated simultaneously with the adaptation function. The number of data packets received from each LSI was almost identical, and the average sampling frequency of 384 capacitance channels (eight for each LSI) was 73.66 Hz.

Digital Systems Validation Handbook. Volume 2. Chapter 18. Avionic Data Bus Integration Technology

DTIC Science & Technology

1993-11-01

interaction between a digital data bus and an avionic system. Very Large Scale Integration (VLSI) ICs and multiversion software, which make up digital...1984, the Sperry Corporation developed a fault tolerant system which employed multiversion programming, voting, and monitoring for error detection and...formulate all the significant behavior of a system. MULTIVERSION PROGRAMMING. N-version programming. N-VERSION PROGRAMMING. The independent coding of a

Trend Monitoring System (TMS) graphics software

NASA Technical Reports Server (NTRS)

Brown, J. S.

1979-01-01

A prototype bus communications systems, which is being used to support the Trend Monitoring System (TMS) and to evaluate the bus concept is considered. A set of FORTRAN-callable graphics subroutines for the host MODCOMP comuter, and an approach to splitting graphics work between the host and the system's intelligent graphics terminals are described. The graphics software in the MODCOMP and the operating software package written for the graphics terminals are included.

Flywheel/Diesel Hybrid Power Drive: Urban Bus Vehicle Simulation.

DOT National Transportation Integrated Search

1978-05-01

This report describes the results of a Transportation Systems Center investigation conducted under Urban Mass Transportation Administration sponsorship, of the practicality of a flywheel/diesel hybrid power drive for urban transit bus propulsion. The...

Risk factors affecting fatal bus accident severity: Their impact on different types of bus drivers.

PubMed

Feng, Shumin; Li, Zhenning; Ci, Yusheng; Zhang, Guohui

2016-01-01

While the bus is generally considered to be a relatively safe means of transportation, the property losses and casualties caused by bus accidents, especially fatal ones, are far from negligible. The reasons for a driver to incur fatalities are different in each case, and it is essential to discover the underlying risk factors of bus fatality severity for different types of drivers in order to improve bus safety. The current study investigates the underlying risk factors of fatal bus accident severity to different types of drivers in the U.S. by estimating an ordered logistic model. Data for the analysis are retrieved from the Buses Involved in Fatal Accidents (BIFA) database from the USA for the years 2006-2010. Accidents are divided into three levels by counting their equivalent fatalities, and the drivers are classified into three clusters by the K-means cluster analysis. The analysis shows that some risk factors have the same impact on different types of drivers, they are: (a) season; (b) day of week; (c) time period; (d) number of vehicles involved; (e) land use; (f) manner of collision; (g) speed limit; (h) snow or ice surface condition; (i) school bus; (j) bus type and seating capacity; (k) driver's age; (l) driver's gender; (m) risky behaviors; and (n) restraint system. Results also show that some risk factors only have impact on the "young and elder drivers with history of traffic violations", they are: (a) section type; (b) number of lanes per direction; (c) roadway profile; (d) wet road surface; and (e) cyclist-bus accident. Notably, history of traffic violations has different impact on different types of bus drivers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spacelab, Spacehab, and Space Station Freedom payload interface projects

NASA Technical Reports Server (NTRS)

Smith, Dean Lance

1992-01-01

Contributions were made to several projects. Howard Nguyen was assisted in developing the Space Station RPS (Rack Power Supply). The RPS is a computer controlled power supply that helps test equipment used for experiments before the equipment is installed on Space Station Freedom. Ron Bennett of General Electric Government Services was assisted in the design and analysis of the Standard Interface Rack Controller hardware and software. An analysis was made of the GPIB (General Purpose Interface Bus), looking for any potential problems while transmitting data across the bus, such as the interaction of the bus controller with a data talker and its listeners. An analysis was made of GPIB bus communications in general, including any negative impact the bus may have on transmitting data back to Earth. A study was made of transmitting digital data back to Earth over a video channel. A report was written about the study and a revised version of the report will be submitted for publication. Work was started on the design of a PC/AT compatible circuit board that will combine digital data with a video signal. Another PC/AT compatible circuit board is being designed to recover the digital data from the video signal. A proposal was submitted to support the continued development of the interface boards after the author returns to Memphis State University in the fall. A study was also made of storing circuit board design software and data on the hard disk server of a LAN (Local Area Network) that connects several IBM style PCs. A report was written that makes several recommendations. A preliminary design review was started of the AIVS (Automatic Interface Verification System). The summer was over before any significant contribution could be made to this project.

Flight Computer Processing Avionics for Space Station Microgravity Experiments: A Risk Assessment of Commercial Off-the-Shelf Utilization

NASA Technical Reports Server (NTRS)

Estes, Howard; Liggin, Karl; Crawford, Kevin; Humphries, Rick (Technical Monitor)

2001-01-01

NASA/Marshall Space Flight Center (MSFC) is continually looking for ways to reduce the costs and schedule and minimize the technical risks during the development of microgravity programs. One of the more prominent ways to minimize the cost and schedule is to use off-the-shelf hardware (OTS). However, the use of OTS often increases the risk. This paper addresses relevant factors considered during the selection and utilization of commercial off-the-shelf (COTS) flight computer processing equipment for the control of space station microgravity experiments. The paper will also discuss how to minimize the technical risks when using COTS processing hardware. Two microgravity experiments for which the COTS processing equipment is being evaluated for are the Equiaxed Dendritic Solidification Experiment (EDSE) and the Self-diffusion in Liquid Elements (SDLE) experiment. Since MSFC is the lead center for Microgravity research, EDSE and SDLE processor selection will be closely watched by other experiments that are being designed to meet payload carrier requirements. This includes the payload carriers planned for the International Space Station (ISS). The purpose of EDSE is to continue to investigate microstructural evolution of, and thermal interactions between multiple dendrites growing under diffusion controlled conditions. The purpose of SDLE is to determine accurate self-diffusivity data as a function of temperature for liquid elements selected as representative of class-like structures. In 1999 MSFC initiated a Center Director's Discretionary Fund (CDDF) effort to investigate and determine the optimal commercial data bus architecture that could lead to faster, better, and lower cost data acquisition systems for the control of microgravity experiments. As part of this effort various commercial data acquisition systems were acquired and evaluated. This included equipment with various form factors, (3U, 6U, others) and equipment that utilized various bus structures, (VME, PC104, STD bus). This evaluation of hardware was performed in conjunction with a trade study that considered over twenty (20) different factors relevant to the selection of an optimum design approach. These factors included; safety, sizing and timing, radiation hardness and single event upset, power consumption, heat dissipation, size and volume, expected service life, maintainability, heritage, operating systems, requirements for software reuse, availability of compatible interface boards, relative cost, schedule, reliability, EMI/EMC factors, "hot swap" capability, standards for conduction cooling, I/O capabilities, unique carrier requirements and operating system considerations. The approach to evaluate Safety as part of this study included a review of the Preliminary Hazard Analysis (PHA) for each of the experiment designs and a determination of how each hazard could be addressed and eliminated when different processors were selected. This included evaluating various design approaches and trade-offs between fault tolerant designs and fail-safe designs in accordance with NSTS 1700.7B. This will include the results of radiation testing where available. Various operating systems, such as VxWorks, Linux, QNX, and Embedded NT are evaluated and the advantages and disadvantages of their utilization are also addressed. Design implementation strategies for the various operating systems are considered and discussed. This paper presents the results and recommendations from this trade study. Preliminary conclusions from this study are that safety concerns from lack or radiation testing on COTS equipment can be addressed by additional testing and design considerations, the PC104 bus provided adequate I/O for the SDLE and EDSE microgravity experiments, and PC104 bus components offered significant advantages over VME and cPCI for weight and space reductions.

Multi-Objective Differential Evolution for Voltage Security Constrained Optimal Power Flow in Deregulated Power Systems

NASA Astrophysics Data System (ADS)

Roselyn, J. Preetha; Devaraj, D.; Dash, Subhransu Sekhar

2013-11-01

Voltage stability is an important issue in the planning and operation of deregulated power systems. The voltage stability problems is a most challenging one for the system operators in deregulated power systems because of the intense use of transmission line capabilities and poor regulation in market environment. This article addresses the congestion management problem avoiding offline transmission capacity limits related to voltage stability by considering Voltage Security Constrained Optimal Power Flow (VSCOPF) problem in deregulated environment. This article presents the application of Multi Objective Differential Evolution (MODE) algorithm to solve the VSCOPF problem in new competitive power systems. The maximum of L-index of the load buses is taken as the indicator of voltage stability and is incorporated in the Optimal Power Flow (OPF) problem. The proposed method in hybrid power market which also gives solutions to voltage stability problems by considering the generation rescheduling cost and load shedding cost which relieves the congestion problem in deregulated environment. The buses for load shedding are selected based on the minimum eigen value of Jacobian with respect to the load shed. In the proposed approach, real power settings of generators in base case and contingency cases, generator bus voltage magnitudes, real and reactive power demands of selected load buses using sensitivity analysis are taken as the control variables and are represented as the combination of floating point numbers and integers. DE/randSF/1/bin strategy scheme of differential evolution with self-tuned parameter which employs binomial crossover and difference vector based mutation is used for the VSCOPF problem. A fuzzy based mechanism is employed to get the best compromise solution from the pareto front to aid the decision maker. The proposed VSCOPF planning model is implemented on IEEE 30-bus system, IEEE 57 bus practical system and IEEE 118 bus system. The pareto optimal front obtained from MODE is compared with reference pareto front and the best compromise solution for all the cases are obtained from fuzzy decision making strategy. The performance measures of proposed MODE in two test systems are calculated using suitable performance metrices. The simulation results show that the proposed approach provides considerable improvement in the congestion management by generation rescheduling and load shedding while enhancing the voltage stability in deregulated power system.

Complexity analysis on public transport networks of 97 large- and medium-sized cities in China

NASA Astrophysics Data System (ADS)

Tian, Zhanwei; Zhang, Zhuo; Wang, Hongfei; Ma, Li

2018-04-01

The traffic situation in Chinese urban areas is continuing to deteriorate. To make a better planning and designing of the public transport system, it is necessary to make profound research on the structure of urban public transport networks (PTNs). We investigate 97 large- and medium-sized cities’ PTNs in China, construct three types of network models — bus stop network, bus transit network and bus line network, then analyze the structural characteristics of them. It is revealed that bus stop network is small-world and scale-free, bus transit network and bus line network are both small-world. Betweenness centrality of each city’s PTN shows similar distribution pattern, although these networks’ size is various. When classifying cities according to the characteristics of PTNs or economic development level, the results are similar. It means that the development of cities’ economy and transport network has a strong correlation, PTN expands in a certain model with the development of economy.

Development and evaluation of a Fault-Tolerant Multiprocessor (FTMP) computer. Volume 3: FTMP test and evaluation

NASA Technical Reports Server (NTRS)

Lala, J. H.; Smith, T. B., III

1983-01-01

The experimental test and evaluation of the Fault-Tolerant Multiprocessor (FTMP) is described. Major objectives of this exercise include expanding validation envelope, building confidence in the system, revealing any weaknesses in the architectural concepts and in their execution in hardware and software, and in general, stressing the hardware and software. To this end, pin-level faults were injected into one LRU of the FTMP and the FTMP response was measured in terms of fault detection, isolation, and recovery times. A total of 21,055 stuck-at-0, stuck-at-1 and invert-signal faults were injected in the CPU, memory, bus interface circuits, Bus Guardian Units, and voters and error latches. Of these, 17,418 were detected. At least 80 percent of undetected faults are estimated to be on unused pins. The multiprocessor identified all detected faults correctly and recovered successfully in each case. Total recovery time for all faults averaged a little over one second. This can be reduced to half a second by including appropriate self-tests.

Evolutionary algorithm for vehicle driving cycle generation.

PubMed

Perhinschi, Mario G; Marlowe, Christopher; Tamayo, Sergio; Tu, Jun; Wayne, W Scott

2011-09-01

Modeling transit bus emissions and fuel economy requires a large amount of experimental data over wide ranges of operational conditions. Chassis dynamometer tests are typically performed using representative driving cycles defined based on vehicle instantaneous speed as sequences of "microtrips", which are intervals between consecutive vehicle stops. Overall significant parameters of the driving cycle, such as average speed, stops per mile, kinetic intensity, and others, are used as independent variables in the modeling process. Performing tests at all the necessary combinations of parameters is expensive and time consuming. In this paper, a methodology is proposed for building driving cycles at prescribed independent variable values using experimental data through the concatenation of "microtrips" isolated from a limited number of standard chassis dynamometer test cycles. The selection of the adequate "microtrips" is achieved through a customized evolutionary algorithm. The genetic representation uses microtrip definitions as genes. Specific mutation, crossover, and karyotype alteration operators have been defined. The Roulette-Wheel selection technique with elitist strategy drives the optimization process, which consists of minimizing the errors to desired overall cycle parameters. This utility is part of the Integrated Bus Information System developed at West Virginia University.

MAP Propulsion System Thermal Design

NASA Technical Reports Server (NTRS)

Mosier, Carol L.

2003-01-01

The propulsion system of the Microwave Anisotropy Probe (MAP) had stringent requirements that made the thermal design unique. To meet instrument stability requirements the system had to be designed to keep temperatures of all components within acceptable limits without heater cycling. Although the spacecraft remains at a fixed 22 sun angle at L2, the variations in solar constant, property degradation, and bus voltage range all significantly affect the temperature. Large portions of the fuel lines are external to the structure and all components are mounted to non-conductive composite structure. These two facts made the sensitivity to the MLI effective emissivity and bus temperature very high. Approximately two years prior to launch the propulsion system was redesigned to meet MAP requirements. The new design utilized hardware that was already installed in order to meet schedule constraints. The spacecraft design and the thermal requirements were changed to compensate for inadequacies of the existing hardware. The propulsion system consists of fuel lines, fill and drain lines/valve, eight thrusters, a HXCM, and a propulsion tank. A voltage regulator was added to keep critical components within limits. Software was developed to control the operational heaters. Trim resistors were put in series with each operational heater circuits and the tank survival heater. A highly sophisticated test program, which included real time model correlation, was developed to determine trim resistors sizes. These trim resistors were installed during a chamber break and verified during thermal balance testing.

49 CFR 571.220 - Standard No. 220; School bus rollover protection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... result from failure of the school bus body structure to withstand forces encountered in rollover crashes. S3. Applicability. This standard applies to school buses. S4. Requirements. When a force in Newtons... roof of the vehicle's body structure through a force application plate as specified in S5, Test...

49 CFR 571.220 - Standard No. 220; School bus rollover protection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... result from failure of the school bus body structure to withstand forces encountered in rollover crashes. S3. Applicability. This standard applies to school buses. S4. Requirements. When a force in Newtons... roof of the vehicle's body structure through a force application plate as specified in S5, Test...

49 CFR 571.220 - Standard No. 220; School bus rollover protection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... result from failure of the school bus body structure to withstand forces encountered in rollover crashes. S3. Applicability. This standard applies to school buses. S4. Requirements. When a force in Newtons... roof of the vehicle's body structure through a force application plate as specified in S5, Test...

49 CFR 571.220 - Standard No. 220; School bus rollover protection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... result from failure of the school bus body structure to withstand forces encountered in rollover crashes. S3. Applicability. This standard applies to school buses. S4. Requirements. When a force in Newtons... roof of the vehicle's body structure through a force application plate as specified in S5, Test...

Ocean Thermal Energy Conversion power system development. Phase I: preliminary design. Final report. [ODSP-3 code; OTEC Steady-State Analysis Program

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

Not Available

1978-12-04

The following appendices are included; Dynamic Simulation Program (ODSP-3); sample results of dynamic simulation; trip report - NH/sub 3/ safety precautions/accident records; trip report - US Coast Guard Headquarters; OTEC power system development, preliminary design test program report; medium turbine generator inspection point program; net energy analysis; bus bar cost of electricity; OTEC technical specifications; and engineer drawings. (WHK)

Micro Cathode Arc Thruster for PhoneSat: Development and Potential Applications

NASA Technical Reports Server (NTRS)

Gazulla, Oriol Tintore; Perez, Andres Dono; Agasid, Elwood; Uribe, Eddie; Trinh, Greenfield; Keidar, Michael; Teel, George; Haque, Samudra; Lukas, Joseph; Salas, Alberto Guillen;

Computer Simulation of an Electric Trolley Bus

DOT National Transportation Integrated Search

1979-12-01

This report describes a computer model developed at the Transportation Systems Center (TSC) to simulate power/propulsion characteristics of an urban trolley bus. The work conducted in this area is sponsored by the Urban Mass Transportation Administra...

Motorcoach and school bus fire safety analysis.

DOT National Transportation Integrated Search

2016-11-01

This report documents a motorcoach and school bus fire safety analysis performed by the John A. Volpe National Transportation Systems Center (Volpe) for the Federal Motor Carrier Safety Administration. This report aims to: 1) identify the causes, fre...

San Diego Wheelchair Accessible Bus Study

DOT National Transportation Integrated Search

1977-09-01

The study describes the implementation and early operation of a pilot project of fixed route, wheelchair accessible bus service on two routes of the San Diego Transit system. Five buses of the Transit Authority fleet were retrofitted with wheelchair ...

View of the current distribution "bus" atop switching cabinets within ...

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

View of the current distribution "bus" atop switching cabinets within the former transformer building. Looking northwest - Childs-Irving Hydroelectric Project, Childs System, Childs Powerhouse, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

Economic Load Dispatch Using Adaptive Social Acceleration Constant Based Particle Swarm Optimization

NASA Astrophysics Data System (ADS)

Jain, N. K.; Nangia, Uma; Jain, Jyoti

2018-04-01

In this paper, an Adaptive Social Acceleration Constant based Particle Swarm Optimization (ASACPSO) has been developed which uses the best value of social acceleration constant (Csg). Three formulations of Csg have been used to search for the best value of Csg. These three formulations led to the development of three algorithms-ALDPSO, AELDPSO-I and AELDPSO-II which were implemented for Economic Load Dispatch of IEEE 5 bus, 14 bus and 30 bus systems. The best value of Csg was selected based on the minimum number of Kounts i.e. number of function evaluations required to minimize the function. This value of Csg was directly used in basic PSO algorithm which led to the development of ASACPSO algorithm. ASACPSO was found to converge faster and give more accurate results compared to BPSO for IEEE 5, 14 and 30 bus systems.

Shunt regulation electric power system

NASA Technical Reports Server (NTRS)

Wright, W. H.; Bless, J. J. (Inventor)

1971-01-01

A regulated electric power system having load and return bus lines is described. A plurality of solar cells interconnected in a power supplying relationship and having a power shunt tap point electrically spaced from the bus lines is provided. A power dissipator is connected to the shunt tap point and provides for a controllable dissipation of excess energy supplied by the solar cells. A dissipation driver is coupled to the power dissipator and controls its conductance and dissipation and is also connected to the solar cells in a power taping relationship to derive operating power therefrom. An error signal generator is coupled to the load bus and to a reference signal generator to provide an error output signal which is representative of the difference between the electric parameters existing at the load bus and the reference signal generator. An error amplifier is coupled to the error signal generator and the dissipation driver to provide the driver with controlling signals.

Increasing throughput of multiplexed electrical bus in pipe-lined architecture

DOEpatents

Asaad, Sameh; Brezzo, Bernard V; Kapur, Mohit

2014-05-27

Techniques are disclosed for increasing the throughput of a multiplexed electrical bus by exploiting available pipeline stages of a computer or other system. For example, a method for increasing a throughput of an electrical bus that connects at least two devices in a system comprises introducing at least one signal hold stage in a signal-receiving one of the two devices, such that a maximum frequency at which the two devices are operated is not limited by a number of cycles of an operating frequency of the electrical bus needed for a signal to propagate from a signal-transmitting one of the two devices to the signal-receiving one of the two devices. Preferably, the signal hold stage introduced in the signal-receiving one of the two devices is a pipeline stage re-allocated from the signal-transmitting one of the two devices.

Optimal Siting and Sizing of Multiple DG Units for the Enhancement of Voltage Profile and Loss Minimization in Transmission Systems Using Nature Inspired Algorithms

PubMed Central

Ramamoorthy, Ambika; Ramachandran, Rajeswari

2016-01-01

Power grid becomes smarter nowadays along with technological development. The benefits of smart grid can be enhanced through the integration of renewable energy sources. In this paper, several studies have been made to reconfigure a conventional network into a smart grid. Amongst all the renewable sources, solar power takes the prominent position due to its availability in abundance. Proposed methodology presented in this paper is aimed at minimizing network power losses and at improving the voltage stability within the frame work of system operation and security constraints in a transmission system. Locations and capacities of DGs have a significant impact on the system losses in a transmission system. In this paper, combined nature inspired algorithms are presented for optimal location and sizing of DGs. This paper proposes a two-step optimization technique in order to integrate DG. In a first step, the best size of DG is determined through PSO metaheuristics and the results obtained through PSO is tested for reverse power flow by negative load approach to find possible bus locations. Then, optimal location is found by Loss Sensitivity Factor (LSF) and weak (WK) bus methods and the results are compared. In a second step, optimal sizing of DGs is determined by PSO, GSA, and hybrid PSOGSA algorithms. Apart from optimal sizing and siting of DGs, different scenarios with number of DGs (3, 4, and 5) and PQ capacities of DGs (P alone, Q alone, and  P and Q both) are also analyzed and the results are analyzed in this paper. A detailed performance analysis is carried out on IEEE 30-bus system to demonstrate the effectiveness of the proposed methodology. PMID:27057557

Optimal Siting and Sizing of Multiple DG Units for the Enhancement of Voltage Profile and Loss Minimization in Transmission Systems Using Nature Inspired Algorithms.

PubMed

Ramamoorthy, Ambika; Ramachandran, Rajeswari

2016-01-01

Power grid becomes smarter nowadays along with technological development. The benefits of smart grid can be enhanced through the integration of renewable energy sources. In this paper, several studies have been made to reconfigure a conventional network into a smart grid. Amongst all the renewable sources, solar power takes the prominent position due to its availability in abundance. Proposed methodology presented in this paper is aimed at minimizing network power losses and at improving the voltage stability within the frame work of system operation and security constraints in a transmission system. Locations and capacities of DGs have a significant impact on the system losses in a transmission system. In this paper, combined nature inspired algorithms are presented for optimal location and sizing of DGs. This paper proposes a two-step optimization technique in order to integrate DG. In a first step, the best size of DG is determined through PSO metaheuristics and the results obtained through PSO is tested for reverse power flow by negative load approach to find possible bus locations. Then, optimal location is found by Loss Sensitivity Factor (LSF) and weak (WK) bus methods and the results are compared. In a second step, optimal sizing of DGs is determined by PSO, GSA, and hybrid PSOGSA algorithms. Apart from optimal sizing and siting of DGs, different scenarios with number of DGs (3, 4, and 5) and PQ capacities of DGs (P alone, Q alone, and P and Q both) are also analyzed and the results are analyzed in this paper. A detailed performance analysis is carried out on IEEE 30-bus system to demonstrate the effectiveness of the proposed methodology.

KSC-99pp1250

NASA Image and Video Library

1999-10-25

On view in front of the Headquarters Building, the Zero Emissions (ZE) transit bus attracts an interested group of employees, including Center Director Roy Bridges (second from left in foreground). Provided by dbb fuel cell engines inc. of Vancouver, Canada, the ZE bus was brought to KSC as part of the Center's Alternative Fuel Initiatives Program. The bus uses a Proton Exchange Membrane fuel cell in which hydrogen and oxygen, from atmospheric air, react to produce electricity that powers an electric motor drive system. The by-product "exhaust" from the fuel cell is water vapor, thus zero harmful emissions. A typical diesel-powered bus emits more than a ton of harmful pollutants from its exhaust every year. Available for viewing by employees, the ZE bus is also being used on tour routes at the KSC Visitor Complex Oct. 26-27

NREL Showcases Hydrogen Internal Combustion Engine Bus, Helps DOE Set Standards for Outreach (Fact Sheet)

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

Not Available

2010-11-01

This fact sheet describes the National Renewable Energy Laboratory's (NREL's) accomplishments in showcasing a Ford hydrogen-powered internal combustion engine (H2ICE) bus at The Taste of Colorado festival in Denver. NREL started using its U.S. Department of Energy-funded H2ICE bus in May 2010 as the primary shuttle vehicle for VIP visitors, members of the media, and new employees. In September 2010, NREL featured the bus at The Taste of Colorado. This was the first major outreach event for the bus. NREL's educational brochure, vehicle wrap designs, and outreach efforts serve as a model for other organizations with DOE-funded H2ICE buses. Workmore » was performed by the Hydrogen Education Group and Market Transformation Group in the Hydrogen Technologies and Systems Center.« less

Statistical Characterization of School Bus Drive Cycles Collected via Onboard Logging Systems

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

Duran, A.; Walkowicz, K.

In an effort to characterize the dynamics typical of school bus operation, National Renewable Energy Laboratory (NREL) researchers set out to gather in-use duty cycle data from school bus fleets operating across the country. Employing a combination of Isaac Instruments GPS/CAN data loggers in conjunction with existing onboard telemetric systems resulted in the capture of operating information for more than 200 individual vehicles in three geographically unique domestic locations. In total, over 1,500 individual operational route shifts from Washington, New York, and Colorado were collected. Upon completing the collection of in-use field data using either NREL-installed data acquisition devices ormore » existing onboard telemetry systems, large-scale duty-cycle statistical analyses were performed to examine underlying vehicle dynamics trends within the data and to explore vehicle operation variations between fleet locations. Based on the results of these analyses, high, low, and average vehicle dynamics requirements were determined, resulting in the selection of representative standard chassis dynamometer test cycles for each condition. In this paper, the methodology and accompanying results of the large-scale duty-cycle statistical analysis are presented, including graphical and tabular representations of a number of relationships between key duty-cycle metrics observed within the larger data set. In addition to presenting the results of this analysis, conclusions are drawn and presented regarding potential applications of advanced vehicle technology as it relates specifically to school buses.« less

Effects of biodiesel on emissions of a bus diesel engine.

PubMed

Kegl, Breda

2008-03-01

This paper discusses the influence of biodiesel on the injection, spray, and engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine with injection M system. The injection, fuel spray, and engine characteristics, obtained with biodiesel, are compared to those obtained with mineral diesel (D2) under various operating regimes. The considered fuel is neat biodiesel from rapeseed oil. Its density, viscosity, surface tension, and sound velocity are determined experimentally and compared to those of D2. The obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. The injection characteristics are determined numerically under the operating regimes, corresponding to the 13 mode ESC test. The fuel spray is obtained experimentally under peak torque condition. Engine characteristics are determined experimentally under 13 mode ESC test conditions. The results indicate that, by using biodiesel, harmful emissions (NO(x), CO, smoke and HC) can be reduced to some extent by adjusting the injection pump timing properly.

The Nett Warrior System: A Case Study for the Acquisition of Soldier Systems

DTIC Science & Technology

2011-12-15

rpfkbpp=C=mr_if`=mlif`v - 10 - k^s^i=mlpqdo^ar^qb=p`elli The evolution of wearable computers continued as an open system– bus wearable design was...established. The success of NW will depend on the program?s ability to incorporate soldier-driven design requirements, commercial technology, and...on the program’s ability to incorporate soldier-driven design requirements, commercial technology, and thorough system testing.   = = ^Åèìáëáíáçå

Lagrangian Hotspots of In-Use NOX Emissions from Transit Buses.

PubMed

Kotz, Andrew J; Kittelson, David B; Northrop, William F

2016-06-07

In-use, spatiotemporal NOX emissions were measured from a conventional powertrain transit bus and a series electric hybrid bus over gradients of route kinetic intensity and ambient temperature. This paper introduces a new method for identifying NOX emissions hotspots along a bus route using high fidelity Lagrangian vehicle data to explore spatial interactions that may influence emissions production. Our study shows that the studied transit buses emit higher than regulated emissions because on-route operation does not accurately represent the range of engine operation tested according to regulatory standards. Using the Lagrangian hotspot detection, we demonstrate that NOX hotspots occurred at bus stops, during cold starts, on inclines, and for accelerations. On the selected routes, bus stops resulted in 3.3 times the route averaged emissions factor in grams/km without significant dependence on bus type or climate. The buses also emitted 2.3 times the route averaged NOX emissions factor at the beginning of each route due to cold selective catalytic reduction aftertreatment temperature. The Lagrangian hotspot detection technique demonstrated here could be employed in future connected vehicles empowered by advances in computational power, data storage capability, and improved sensor technology to optimize emissions as a function of spatial location.

System design of the Pioneer Venus spacecraft. Volume 3: Systems analysis

NASA Technical Reports Server (NTRS)

Fisher, J. N.

1973-01-01

The mission, systems, operations, ground systems, and reliability analysis of the Thor/Delta baseline design used for the Pioneer Space Probe are discussed. Tradeoff decisions concerning spin axis orientation, bus antenna design, communication system design, probe descent, and reduced science payload are analyzed. The reliability analysis is made for the probe bus mission, large probe mission, and small probe mission. Detailed mission sequences were established to identify critical areas and provide phasing of critical operation.

Multimode marine engine room simulation system based on field bus technology

NASA Astrophysics Data System (ADS)

Zheng, Huayao; Deng, Linlin; Guo, Yi

2003-09-01

Developing multi mode MER (Marine Engine Room) Labs is the main work in Marine Simulation Center, which is the key lab of Communication Ministry of China. It includes FPP (Fixed Pitch Propeller) and CPP (Controllable Pitch Propeller) mode MER simulation systems, integrated electrical propulsion mode MER simulation system, physical mode MER lab, etc. FPP mode simulation system, which was oriented to large container ship, had been completed since 1999, and got second level of Shanghai Municipal Science and Technical Progress award. This paper mainly introduces the recent development and achievements of Marine Simulation Center. Based on the Lon Works field bus, the structure characteristics and control strategies of completely distributed intelligent control network are discussed. The experiment mode of multi-nodes field bus detection and control system is described. Besides, intelligent fault diagnosis technology about some mechatronics integration control systems explored is also involved.

A fast adaptive convex hull algorithm on two-dimensional processor arrays with a reconfigurable BUS system

NASA Technical Reports Server (NTRS)

Olariu, S.; Schwing, J.; Zhang, J.

1991-01-01

A bus system that can change dynamically to suit computational needs is referred to as reconfigurable. We present a fast adaptive convex hull algorithm on a two-dimensional processor array with a reconfigurable bus system (2-D PARBS, for short). Specifically, we show that computing the convex hull of a planar set of n points taken O(log n/log m) time on a 2-D PARBS of size mn x n with 3 less than or equal to m less than or equal to n. Our result implies that the convex hull of n points in the plane can be computed in O(1) time in a 2-D PARBS of size n(exp 1.5) x n.

A Conceptual Approach for Optimising Bus Stop Spacing

NASA Astrophysics Data System (ADS)

Johar, Amita; Jain, S. S.; Garg, P. k.

2017-06-01

An efficient public transportation system is essential of any country. The growth, development and shape of the urban areas are mainly due to availability of good transportation (Shah et al. in Inst Town Plan India J 5(3):50-59, 1). In developing countries, like India, travel by local bus in a city is very common. The accidents, congestion, pollution and appropriate location of bus stops are the major problems arising in metropolitan cities. Among all the metropolitan cities in India, Delhi has highest percentage of growth of population and vehicles. Therefore, it is important to adopt efficient and effective ways to improve mobility in different metropolitan cities in order to overcome the problem and to reduce the number of private vehicles on the road. The primary objective of this paper is to present a methodology for developing a model for optimum bus stop spacing (OBSS). It describes the evaluation of existing urban bus route, data collection, development of model for optimizing urban bus route and application of model. In this work, the bus passenger generalized cost method is used to optimize the spacing between bus stops. For the development of model, a computer program is required to be written. The applicability of the model has been evaluated by taking the data of urban bus route of Delhi Transport Corporation (DTC) in Excel sheet in first phase. Later on, it is proposed to develop a programming in C++ language. The developed model is expected to be useful to transport planner for rational design of the spacing of bus stops to save travel time and to generalize operating cost. After analysis it is found that spacing between the bus stop comes out to be between 250 and 500 m. The Proposed Spacing of bus stops is done considering the points that they don't come nearer to metro/rail station, entry or exit of flyover and near traffic signal.

Exact and Metaheuristic Approaches for a Bi-Objective School Bus Scheduling Problem

PubMed Central

Chen, Xiaopan; Kong, Yunfeng; Dang, Lanxue; Hou, Yane; Ye, Xinyue

2015-01-01

As a class of hard combinatorial optimization problems, the school bus routing problem has received considerable attention in the last decades. For a multi-school system, given the bus trips for each school, the school bus scheduling problem aims at optimizing bus schedules to serve all the trips within the school time windows. In this paper, we propose two approaches for solving the bi-objective school bus scheduling problem: an exact method of mixed integer programming (MIP) and a metaheuristic method which combines simulated annealing with local search. We develop MIP formulations for homogenous and heterogeneous fleet problems respectively and solve the models by MIP solver CPLEX. The bus type-based formulation for heterogeneous fleet problem reduces the model complexity in terms of the number of decision variables and constraints. The metaheuristic method is a two-stage framework for minimizing the number of buses to be used as well as the total travel distance of buses. We evaluate the proposed MIP and the metaheuristic method on two benchmark datasets, showing that on both instances, our metaheuristic method significantly outperforms the respective state-of-the-art methods. PMID:26176764

Thermographic inspection and quality assurance of energy conservation procedures for electric buses

NASA Astrophysics Data System (ADS)

Fennell, Henri C.

1998-03-01

Electric buses are one of the solutions for improving air quality in our cities. Many states are adopting 'no new diesel bus' policies, thus increasing the pressure to develop alternative vehicles. The fledgling electric vehicle technology suffers from acceptance problems by major transit authorities due primarily to limited travel range from each battery charge. Utilizing electric buses in the Northeast has the added problem of maintaining an adequate cabin temperature without the availability of heat from a diesel motor. Heating the passenger cabin with an electric heater which draws from the batteries' stored energy significantly reduces the already modest range of these vehicles; therefore, energy conservation measures play an important role in allowing electric vehicles to provide practical transit services. IR thermography, in conjunction with air leakage pressurization diagnostics, has proven to be an excellent tool for developing energy-efficient bus designs as well as a valuable in-service performance testing method. This paper is based on tests performed on several Advanced Vehicle Systems, Inc. electric buses during research performed under Northeast Alternative Vehicle Consortium and Defense Advanced Research Projects Agency grants. The work demonstrates the thermographic methods used and the real- world increased performance of retrofitted and newly designed buses resulting from this initial Portland Transit retrofit project and in a follow-up project to develop a cold weather specification for a new generation of electric buses. Early diagnostic and new-technology follow-up thermographic performance testing was paralleled by energy modeling of early baseline and re-designed vehicles. Modeling and performance data are included. As a result of this research, thermography, air-leakage/pressurization testing, and fog analysis techniques are now being used regularly in research and development and quality assurance procedures by electric bus manufacturers.

Oxygen Generation System Laptop Bus Controller Flight Software

NASA Technical Reports Server (NTRS)

Rowe, Chad; Panter, Donna

2009-01-01

The Oxygen Generation System Laptop Bus Controller Flight Software was developed to allow the International Space Station (ISS) program to activate specific components of the Oxygen Generation System (OGS) to perform a checkout of key hardware operation in a microgravity environment, as well as to perform preventative maintenance operations of system valves during a long period of what would otherwise be hardware dormancy. The software provides direct connectivity to the OGS Firmware Controller with pre-programmed tasks operated by on-orbit astronauts to exercise OGS valves and motors. The software is used to manipulate the pump, separator, and valves to alleviate the concerns of hardware problems due to long-term inactivity and to allow for operational verification of microgravity-sensitive components early enough so that, if problems are found, they can be addressed before the hardware is required for operation on-orbit. The decision was made to use existing on-orbit IBM ThinkPad A31p laptops and MIL-STD-1553B interface cards as the hardware configuration. The software at the time of this reporting was developed and tested for use under the Windows 2000 Professional operating system to ensure compatibility with the existing on-orbit computer systems.

Texas Hydrogen Highway Fuel Cell Hybrid Bus and Fueling Infrastructure Technology Showcase - Final Scientific/Technical Report

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

Hitchcock, David

The Texas Hydrogen Highway project has showcased a hydrogen fuel cell transit bus and hydrogen fueling infrastructure that was designed and built through previous support from various public and private sector entities. The aim of this project has been to increase awareness among transit agencies and other public entities on these transportation technologies, and to place such technologies into commercial applications, such as a public transit agency. The initial project concept developed in 2004 was to show that a skid-mounted, fully-integrated, factory-built and tested hydrogen fueling station could be used to simplify the design, and lower the cost of fuelingmore » infrastructure for fuel cell vehicles. The approach was to design, engineer, build, and test the integrated fueling station at the factory then install it at a site that offered educational and technical resources and provide an opportunity to showcase both the fueling station and advanced hydrogen vehicles. The two primary technology components include: Hydrogen Fueling Station: The hydrogen fueling infrastructure was designed and built by Gas Technology Institute primarily through a funding grant from the Texas Commission on Environmental Quality. It includes hydrogen production, clean-up, compression, storage, and dispensing. The station consists of a steam methane reformer, gas clean-up system, gas compressor and 48 kilograms of hydrogen storage capacity for dispensing at 5000 psig. The station is skid-mounted for easy installation and can be relocated if needed. It includes a dispenser that is designed to provide temperaturecompensated fills using a control algorithm. The total station daily capacity is approximately 50 kilograms. Fuel Cell Bus: The transit passenger bus built by Ebus, a company located in Downey, CA, was commissioned and acquired by GTI prior to this project. It is a fuel cell plug-in hybrid electric vehicle which is ADA compliant, has air conditioning sufficient for Texas operations, and regenerative braking for battery charging. It uses a 19.3 kW Ballard PEM fuel cell, will store 12.6 kg of hydrogen at 350 Bar, and includes a 60 kWh battery storage system. The objectives of the project included the following: (a) To advance commercialization of hydrogen-powered transit buses and supporting infrastructure; (b) To provide public outreach and education by showcasing the operation of a 22-foot fuel cell hybrid shuttle bus and Texas first hydrogen fueling infrastructure; and (c) To showcase operation of zero-emissions vehicle for potential transit applications. As mentioned above, the project successfully demonstrated an early vehicle technology, the Ebus plug-in hybrid fuel cell bus, and that success has led to the acquisition of a more advanced vehicle that can take advantage of the same fueling infrastructure. Needed hydrogen station improvements have been identified that will enhance the capabilities of the fueling infrastructure to serve the new bus and to meet the transit agency needs. Over the course of this project, public officials, local government staff, and transit operators were engaged in outreach and education activities that acquainted them with the real world operation of a fuel cell bus and fueling infrastructure. Transit staff members in the Dallas/Ft. Worth region were invited to a workshop in Arlington, Texas at the North Central Texas Council of Governments to participate in a workshop on hydrogen and fuel cells, and to see the fuel cell bus in operation. The bus was trucked to the meeting for this purpose so that participants could see and ride the bus. Austin area transit staff members visited the fueling site in Austin to be briefed on the bus and to participate in a fueling demonstration. This led to further meetings to determine how a fuel cell bus and fueling station could be deployed at Capital Metro Transit. Target urban regions that expressed additional interest during the project in response to the outreach meetings and showcase events include San Antonio and Austin, Texas. In summary, the project objectives were achieved in the following ways: Through presentations and papers provided to a variety of audiences in multiple venues, the project team fulfilled its goal of providing education and outreach on hydrogen technology to statewide audiences. The project team generated interest that exists well beyond the completion of the project, and indeed, helped to generate financial support for a subsequent hydrogen vehicle project in Austin. The University of Texas, Center for ElectroMechanics operated the fuel cell-electric Ebus vehicle for over 13,000 miles in Austin, Texas in a variety of routes and loading configurations. The project took advantage of prior efforts that created a hydrogen fueling station and fuel cell electric-hybrid bus and continued to verify their technical foundation, while informing and educating potential future users of how these technologies work.« less

Crashworthiness evaluation of mass transit buses.

DOT National Transportation Integrated Search

2008-11-01

Mass transit bus systems are an integral part of the national transportation network, serving more than 20.6 billion passenger-miles per year with a relatively low fatality rate. Bus occupant injuries are evenly distributed among crashes on all sides...

HEARING IMPAIRMENT AND HYPERTENSION AMONG LONG DISTANCE BUS DRIVERS

PubMed Central

Abdelmoneim, Ismail

2003-01-01

Objectives: To investigate the prevalence of possible hearing impairment and hypertension in long distance bus drivers compared to the city bus drivers in Abha city. Methods: This was a cross-sectional study involving 62 long distance bus drivers and 46 city bus drivers from October 2001 to March 2002. A specially-designed questionnaire was administered to the drivers to explore some of their socioeconomic backgrounds. A pure tone air conduction audiometry and blood pressure measurements were performed. Results: Long distance bus drivers’ workload is significantly higher than that of city drivers (total weekly hours 64.0±14.3 compared to 46.7±5.5). Hearing impairment was significantly more among long distance drivers in the frequencies of 250, 500, 1000 and 2000 Hz especially in the left ear even after age corrections. The prevalence of mild hearing loss and hypertension were also higher among the long distance drivers (19.4% vs 4.5% and 38.7% vs 13% respectively). Conclusion and recommendations: This study showed more hearing affection and a higher prevalence of hypertension among long distance bus drivers than their counterparts operating in the city. Their hearing acuity should be tested before they start work and regularly afterwards. The stresses and strains of the job should be further studied and relieved; and regular health checks including blood pressure monitoring are to be instituted. PMID:23012034

Thermal Expert System (TEXSYS): Systems automony demonstration project, volume 1. Overview

NASA Technical Reports Server (NTRS)

Glass, B. J. (Editor)

1992-01-01

The Systems Autonomy Demonstration Project (SADP) produced a knowledge-based real-time control system for control and fault detection, isolation, and recovery (FDIR) of a prototype two-phase Space Station Freedom external active thermal control system (EATCS). The Thermal Expert System (TEXSYS) was demonstrated in recent tests to be capable of reliable fault anticipation and detection, as well as ordinary control of the thermal bus. Performance requirements were addressed by adopting a hierarchical symbolic control approach-layering model-based expert system software on a conventional, numerical data acquisition and control system. The model-based reasoning capabilities of TEXSYS were shown to be advantageous over typical rule-based expert systems, particularly for detection of unforeseen faults and sensor failures. Volume 1 gives a project overview and testing highlights. Volume 2 provides detail on the EATCS test bed, test operations, and online test results. Appendix A is a test archive, while Appendix B is a compendium of design and user manuals for the TEXSYS software.

Surface elastic wave detectors

NASA Technical Reports Server (NTRS)

Lawson, R. L.

1971-01-01

The potential applications of acoustic surface wave technology to multiplex communication systems such as data-bus, are examined. The goals are primarily to characterize certain aspects of surface wave trapped delay lines, surface wave modulation techniques, and surface wave applications that are relevant to the evaluation of surface wave devices in multiplex systems. The results indicate that there is a potential for the application of surface wave technology in data-bus type systems.

In-use fuel economy of hybrid-electric school buses in Iowa.

PubMed

Hallmark, Shauna; Sperry, Bob; Mudgal, Abhisek

2011-05-01

Although it is much safer and more fuel-efficient to transport children to school in buses than in private vehicles, school buses in the United States still consume 822 million gal of diesel fuel annually, and school transportation costs can account for a significant portion of resource-constrained school district budgets. Additionally, children in diesel-powered school buses may be exposed to higher levels of particulates and other pollutants than children in cars. One solution to emission and fuel concerns is use of hybrid-electric school buses, which have the potential to reduce emissions and overall lifecycle costs compared with conventional diesel buses. Hybrid-electric technologies are available in the passenger vehicle market as well as the transit bus market and have a track record indicating fuel economy and emissions benefits. This paper summarizes the results of an in-use fuel economy evaluation for two plug-in hybrid school buses deployed in two different school districts in Iowa. Each school district selected a control bus with a route similar to that of the hybrid bus. Odometer readings, fuel consumption, and maintenance needs were recorded for each bus. The buses were deployed in 2008 and data were collected through May 2010. Fuel consumption was calculated for each school district. In Nevada, IA, the overall average fuel economy was 8.23 mpg for the hybrid and 6.35 mpg for the control bus. In Sigourney, IA, the overall average fuel economy was 8.94 mpg for the hybrid and 6.42 mpg for the control bus. The fuel consumption data were compared for the hybrid and control buses using a Wilcoxon signed rank test. Results indicate that fuel economy for the Nevada hybrid bus was 29.6% better than for the Nevada control bus, and fuel economy for the Sigourney hybrid bus was 39.2% higher than for the Sigourney control bus. Both differences were statistically significant.

Design and fabrication of a full-scale actively controlled satellite appendage simulator unit

NASA Astrophysics Data System (ADS)

Jacobs, Jack H.; Quenon, Dan; Hadden, Steve; Self, Rick

1999-07-01

Modern satellites require the ability to slew and settle quickly in order to acquire or transmit data efficiently. Solar arrays and communication antennas cause low frequency disturbances to the satellite bus during these maneuvers causing undesirable induced vibration of the payload. The ability to develop and experimentally demonstrate attitude control laws which compensate for these flexible body disturbances is of prime importance to modern day satellite manufacturers. Honeywell has designed and fabricated an actively controlled Appendage Simulator Unit (ASU) which can physically induce the modal characteristics of satellite appendages on to a ground based satellite test bed installed on an air bearing. The ASU consists of two orthogonal fulcrum beams weighting over 800 pounds each utilizing two electrodynamic shakers to induce active torques onto the bus. The ASU is programmed with the state space characteristics of the desired appendage and responds in real time to the bus motion to generate realistic disturbances back onto the satellite. Two LVDT's are used on each fulcrum beam to close the loop and insure the system responds in real time the same way a real solar array would on-orbit. Each axis is independently programmable in order to simulate various orientations or modal contributions from an appendage. The design process for the ASU involved the optimization of sensors, actuators, control authority, weight, power and functionality. The smart structure system design process and experimental results are described in detail.

Task Analysis Assessment on Intrastate Bus Traffic Controllers

NASA Astrophysics Data System (ADS)

Yen Bin, Teo; Azlis-Sani, Jalil; Nur Annuar Mohd Yunos, Muhammad; Ismail, S. M. Sabri S. M.; Tajedi, Noor Aqilah Ahmad

2016-11-01

Public transportation acts as social mobility and caters the daily needs of the society for passengers to travel from one place to another. This is true for a country like Malaysia where international trade has been growing significantly over the past few decades. Task analysis assessment was conducted with the consideration of cognitive ergonomic view towards problem related to human factors. Conducting research regarding the task analysis on bus traffic controllers had allowed a better understanding regarding the nature of work and the overall monitoring activities of the bus services. This paper served to study the task analysis assessment on intrastate bus traffic controllers and the objectives of this study include to conduct task analysis assessment on the bus traffic controllers. Task analysis assessment for the bus traffic controllers was developed via Hierarchical Task Analysis (HTA). There are a total of five subsidiary tasks on level one and only two were able to be further broken down in level two. Development of HTA allowed a better understanding regarding the work and this could further ease the evaluation of the tasks conducted by the bus traffic controllers. Thus, human error could be reduced for the safety of all passengers and increase the overall efficiency of the system. Besides, it could assist in improving the operation of the bus traffic controllers by modelling or synthesizing the existing tasks if necessary.

Exploring how to make system safety work in transit

DOT National Transportation Integrated Search

1994-12-01

The New York Metropolitan Transit Authority (MTA) and its operating elements, the New York City Transit Authority (NYCTA), the Long Island Rail Road (LIRR), Metro-North Commuter Railroad, Long Island Bus (LI Bus), and the Staten Island Rapid Transit ...

Highlights of the Transit Bus Technology Workshop - April 29-30, 1982

DOT National Transportation Integrated Search

1982-09-01

The Transit Bus Technology Workshop, held at the Transportation Systems Center on April 29-30, 1982, provided UMTA with current information on research, development, and technical assistance needed to improve the economy and performance of transit bu...

Proton exchange membrane fuel cell system diagnosis based on the signed directed graph method

NASA Astrophysics Data System (ADS)

Hua, Jianfeng; Lu, Languang; Ouyang, Minggao; Li, Jianqiu; Xu, Liangfei

The fuel-cell powered bus is becoming the favored choice for electric vehicles because of its extended driving range, zero emissions, and high energy conversion efficiency when compared with battery-operated electric vehicles. In China, a demonstration program for the fuel cell bus fleet operated at the Beijing Olympics in 2008 and the Shanghai Expo in 2010. It is necessary to develop comprehensive proton exchange membrane fuel cell (PEMFC) diagnostic tools to increase the reliability of these systems. It is especially critical for fuel-cell city buses serving large numbers of passengers using public transportation. This paper presents a diagnostic analysis and implementation study based on the signed directed graph (SDG) method for the fuel-cell system. This diagnostic system was successfully implemented in the fuel-cell bus fleet at the Shanghai Expo in 2010.

A PC-based bus monitor program for use with the transport systems research vehicle RS-232 communication interfaces

NASA Technical Reports Server (NTRS)

Easley, Wesley C.

1991-01-01

Experiment critical use of RS-232 data busses in the Transport Systems Research Vehicle (TSRV) operated by the Advanced Transport Operating Systems Program Office at the NASA Langley Research Center has recently increased. Each application utilizes a number of nonidentical computer and peripheral configurations and requires task specific software development. To aid these development tasks, an IBM PC-based RS-232 bus monitoring system was produced. It can simultaneously monitor two communication ports of a PC or clone, including the nonstandard bus expansion of the TSRV Grid laptop computers. Display occurs in a separate window for each port's input with binary display being selectable. A number of other features including binary log files, screen capture to files, and a full range of communication parameters are provided.

International Space Station Bus Regulation With NASA Glenn Research Center Flywheel Energy Storage System Development Unit

NASA Technical Reports Server (NTRS)

Kascak, Peter E.; Kenny, Barbara H.; Dever, Timothy P.; Santiago, Walter; Jansen, Ralph H.

2001-01-01

An experimental flywheel energy storage system is described. This system is being used to develop a flywheel based replacement for the batteries on the International Space Station (ISS). Motor control algorithms which allow the flywheel to interface with a simplified model of the ISS power bus, and function similarly to the existing ISS battery system, are described. Results of controller experimental verification on a 300 W-hr flywheel are presented.

Electrical Design and Evaluation of Asynchronous Serial Bus Communication Network of 48 Sensor Platform LSIs with Single-Ended I/O for Integrated MEMS-LSI Sensors

PubMed Central

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki

2018-01-01

For installing many sensors in a limited space with a limited computing resource, the digitization of the sensor output at the site of sensation has advantages such as a small amount of wiring, low signal interference and high scalability. For this purpose, we have developed a dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) (referred to as “sensor platform LSI”) for bus-networked Micro-Electro-Mechanical-Systems (MEMS)-LSI integrated sensors. In this LSI, collision avoidance, adaptation and event-driven functions are simply implemented to relieve data collision and congestion in asynchronous serial bus communication. In this study, we developed a network system with 48 sensor platform LSIs based on Printed Circuit Board (PCB) in a backbone bus topology with the bus length being 2.4 m. We evaluated the serial communication performance when 48 LSIs operated simultaneously with the adaptation function. The number of data packets received from each LSI was almost identical, and the average sampling frequency of 384 capacitance channels (eight for each LSI) was 73.66 Hz. PMID:29342923

Optimation of Operation System Integration between Main and Feeder Public Transport (Case Study: Trans Jakarta-Kopaja Bus Services)

NASA Astrophysics Data System (ADS)

Miharja, M.; Priadi, Y. N.

2018-05-01

Promoting a better public transport is a key strategy to cope with urban transport problems which are mostly caused by a huge private vehicle usage. A better public transport service quality not only focuses on one type of public transport mode, but also concerns on inter modes service integration. Fragmented inter mode public transport service leads to a longer trip chain as well as average travel time which would result in its failure to compete with a private vehicle. This paper examines the optimation process of operation system integration between Trans Jakarta Bus as the main public transport mode and Kopaja Bus as feeder public transport service in Jakarta. Using scoring-interview method combined with standard parameters in operation system integration, this paper identifies the key factors that determine the success of the two public transport operation system integrations. The study found that some key integration parameters, such as the cancellation of “system setoran”, passenger get in-get out at official stop points, and systematic payment, positively contribute to a better service integration. However, some parameters such as fine system, time and changing point reliability, and information system reliability are among those which need improvement. These findings are very useful for the authority to set the right strategy to improve operation system integration between Trans Jakarta and Kopaja Bus services.

Modeling and Simulation of Bus Dispatching Policy for Timed Transfers on Signalized Networks

NASA Astrophysics Data System (ADS)

Cho, Hsun-Jung; Lin, Guey-Shii

2007-12-01

The major work of this study is to formulate the system cost functions and to integrate the bus dispatching policy with signal control. The integrated model mainly includes the flow dispersion model for links, signal control model for nodes, and dispatching control model for transfer terminals. All such models are inter-related for transfer operations in one-center transit network. The integrated model that combines dispatching policies with flexible signal control modes can be applied to assess the effectiveness of transfer operations. It is found that, if bus arrival information is reliable, an early dispatching decision made at the mean bus arrival times is preferable. The costs for coordinated operations with slack times are relatively low at the optimal common headway when applying adaptive route control. Based on such findings, a threshold function of bus headway for justifying an adaptive signal route control under various time values of auto drivers is developed.

Demonstration Advanced Avionics System (DAAS)

NASA Technical Reports Server (NTRS)

1982-01-01

The feasibility of developing an integrated avionics system suitable for general aviation was determined. A design of reliable integrated avionics which provides expanded functional capability that significantly enhances the utility and safety of general aviation at a cost commensurate with the general aviation market was developed. The use of a data bus, microprocessors, electronic displays and data entry devices, and improved function capabilities were emphasized. An avionics system capable of evaluating the most critical and promising elements of an integrated system was designed, built and flight tested in a twin engine general aviation aircraft.

Avionic Data Bus Integration Technology

DTIC Science & Technology

1991-12-01

address the hardware-software interaction between a digital data bus and an avionic system. Very Large Scale Integration (VLSI) ICs and multiversion ...the SCP. In 1984, the Sperry Corporation developed a fault tolerant system which employed multiversion programming, voting, and monitoring for error... MULTIVERSION PROGRAMMING. N-version programming. 226 N-VERSION PROGRAMMING. The independent coding of a number, N, of redundant computer programs that

Serial Back-Plane Technologies in Advanced Avionics Architectures

NASA Technical Reports Server (NTRS)

Varnavas, Kosta

2005-01-01

Current back plane technologies such as VME, and current personal computer back planes such as PCI, are shared bus systems that can exhibit nondeterministic latencies. This means a card can take control of the bus and use resources indefinitely affecting the ability of other cards in the back plane to acquire the bus. This provides a real hit on the reliability of the system. Additionally, these parallel busses only have bandwidths in the 100s of megahertz range and EMI and noise effects get worse the higher the bandwidth goes. To provide scalable, fault-tolerant, advanced computing systems, more applicable to today s connected computing environment and to better meet the needs of future requirements for advanced space instruments and vehicles, serial back-plane technologies should be implemented in advanced avionics architectures. Serial backplane technologies eliminate the problem of one card getting the bus and never relinquishing it, or one minor problem on the backplane bringing the whole system down. Being serial instead of parallel improves the reliability by reducing many of the signal integrity issues associated with parallel back planes and thus significantly improves reliability. The increased speeds associated with a serial backplane are an added bonus.

Naval Remote Ocean Sensing System (NROSS) study

NASA Technical Reports Server (NTRS)

1983-01-01

A set of hardware similar to the SEASAT A configuration requirement, suitable for installation and operation aboard a NOAA-D bus and a budgetary cost for one (1) protoflight model was provided. The scatterometer sensor is conceived as one of several sensors for the Navy Remote Ocean Sensing System (NROSS) Satellite Program. Deliverables requested were to include a final report with appropriate sketches and block diagrams showing the scatterometer design/configuration and a budgetary cost for all labor and materials to design, fabricate, test, and integrate this hardware into a NOAA-D satellite bus. This configuration consists of two (2) hardware assembles - a transmitter/receiver (T/R) assembly and an integrated electronics assembly (IEA). The T/R assembly as conceived is best located at the extreme opposite end of the satellite away from the solar array assembly and oriented in position to enable one surface of the assembly to have unobstructed exposure to space. The IEA is planned to be located at the bottom (Earth viewing) side of the satellite and requires a radiating plate.

Developing a discrete event simulation model for university student shuttle buses

NASA Astrophysics Data System (ADS)

Zulkepli, Jafri; Khalid, Ruzelan; Nawawi, Mohd Kamal Mohd; Hamid, Muhammad Hafizan

2017-11-01

Providing shuttle buses for university students to attend their classes is crucial, especially when their number is large and the distances between their classes and residential halls are far. These factors, in addition to the non-optimal current bus services, typically require the students to wait longer which eventually opens a space for them to complain. To considerably reduce the waiting time, providing the optimal number of buses to transport them from location to location and the effective route schedules to fulfil the students' demand at relevant time ranges are thus important. The optimal bus number and schedules are to be determined and tested using a flexible decision platform. This paper thus models the current services of student shuttle buses in a university using a Discrete Event Simulation approach. The model can flexibly simulate whatever changes configured to the current system and report its effects to the performance measures. How the model was conceptualized and formulated for future system configurations are the main interest of this paper.

Radial Basis Function Neural Network Application to Power System Restoration Studies

PubMed Central

Sadeghkhani, Iman; Ketabi, Abbas; Feuillet, Rene

2012-01-01

One of the most important issues in power system restoration is overvoltages caused by transformer switching. These overvoltages might damage some equipment and delay power system restoration. This paper presents a radial basis function neural network (RBFNN) to study transformer switching overvoltages. To achieve good generalization capability for developed RBFNN, equivalent parameters of the network are added to RBFNN inputs. The developed RBFNN is trained with the worst-case scenario of switching angle and remanent flux and tested for typical cases. The simulated results for a partial of 39-bus New England test system show that the proposed technique can estimate the peak values and duration of switching overvoltages with good accuracy. PMID:22792093

An implementation of particle swarm optimization to evaluate optimal under-voltage load shedding in competitive electricity markets

NASA Astrophysics Data System (ADS)

Hosseini-Bioki, M. M.; Rashidinejad, M.; Abdollahi, A.

2013-11-01

Load shedding is a crucial issue in power systems especially under restructured electricity environment. Market-driven load shedding in reregulated power systems associated with security as well as reliability is investigated in this paper. A technoeconomic multi-objective function is introduced to reveal an optimal load shedding scheme considering maximum social welfare. The proposed optimization problem includes maximum GENCOs and loads' profits as well as maximum loadability limit under normal and contingency conditions. Particle swarm optimization (PSO) as a heuristic optimization technique, is utilized to find an optimal load shedding scheme. In a market-driven structure, generators offer their bidding blocks while the dispatchable loads will bid their price-responsive demands. An independent system operator (ISO) derives a market clearing price (MCP) while rescheduling the amount of generating power in both pre-contingency and post-contingency conditions. The proposed methodology is developed on a 3-bus system and then is applied to a modified IEEE 30-bus test system. The obtained results show the effectiveness of the proposed methodology in implementing the optimal load shedding satisfying social welfare by maintaining voltage stability margin (VSM) through technoeconomic analyses.

Nonlinear Model Reduction in Power Systems by Balancing of Empirical Controllability and Observability Covariances

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

Qi, Junjian; Wang, Jianhui; Liu, Hui

Abstract: In this paper, nonlinear model reduction for power systems is performed by the balancing of empirical controllability and observability covariances that are calculated around the operating region. Unlike existing model reduction methods, the external system does not need to be linearized but is directly dealt with as a nonlinear system. A transformation is found to balance the controllability and observability covariances in order to determine which states have the greatest contribution to the input-output behavior. The original system model is then reduced by Galerkin projection based on this transformation. The proposed method is tested and validated on a systemmore » comprised of a 16-machine 68-bus system and an IEEE 50-machine 145-bus system. The results show that by using the proposed model reduction the calculation efficiency can be greatly improved; at the same time, the obtained state trajectories are close to those for directly simulating the whole system or partitioning the system while not performing reduction. Compared with the balanced truncation method based on a linearized model, the proposed nonlinear model reduction method can guarantee higher accuracy and similar calculation efficiency. It is shown that the proposed method is not sensitive to the choice of the matrices for calculating the empirical covariances.« less

Guidelines for bus transit stops in highway construction work zones.

DOT National Transportation Integrated Search

2014-12-01

Fixed route transit systems provide a valuable transportation service for many of our citizens. As users depend on : bus transit to access to the essentials of life, maintaining transit service is a critical issue. Given the extent of : nationwide bu...

Evaluation of bus transit reliability in the District of Columbia.

DOT National Transportation Integrated Search

2013-11-01

Several performance metrics can be used to assess the reliability of a transit system. These include on-time arrivals, travel-time : adherence, run-time adherence, and customer satisfaction, among others. On-time arrival at bus stops is one of the pe...

Side Object Detection Systems Evaluation : Final Evaluation Report.

DOT National Transportation Integrated Search

2008-12-15

Nearly 46 percent of bus accidents across the United States each year occur on the left or right side of the bus. These collisions result in property damage, and they can negatively impact on revenue operations and public perception. The first commer...

Design & development of the LCO-140H series hydraulic hybrid low floor transit bus.

DOT National Transportation Integrated Search

2012-09-01

Automation Alley, Altair, and the Federal Transit Administration (FTA), in a public-private partnership, teamed up to advance a new transit bus initiative that would improve Americas local and regional transit systems while requiring no infrastruc...

Zero Emission Bay Area (ZEBA) Fuel Cell Bus Demonstration Results : Third Report

DOT National Transportation Integrated Search

2014-05-01

This report presents results of a demonstration of 12 fuel cell electric buses (FCEB) operating in Oakland, California. The FCEBs have a fuel cell dominant hybrid electric propulsion system in a series configuration. The bus manufacturerVan Hool...

Zero Emission Bay Area (ZEBA) Fuel Cell Bus Demonstration : Second Results Report

DOT National Transportation Integrated Search

2012-07-04

This report presents results of a demonstration of 12 new fuel cell electric buses (FCEB) operating in Oakland, California. The FCEBs have a fuel cell dominant hybrid electric propulsion system in a series configuration. The bus manufacturerVan Ho...

Glacier Going to the Sun Road Rehabilitation Mitigation Shuttle Bus Evaluation.

DOT National Transportation Integrated Search

2008-03-31

As a mitigation measure during reconstruction of the Going to the Sun Road, Glacier National Park operated a shuttle bus system along three routes during the 2007 season. This report presents a multi-dimensional evaluation of the transportation servi...

Improvement of multiprocessing performance by using optical centralized shared bus

NASA Astrophysics Data System (ADS)

Han, Xuliang; Chen, Ray T.

2004-06-01

With the ever-increasing need to solve larger and more complex problems, multiprocessing is attracting more and more research efforts. One of the challenges facing the multiprocessor designers is to fulfill in an effective manner the communications among the processes running in parallel on multiple multiprocessors. The conventional electrical backplane bus provides narrow bandwidth as restricted by the physical limitations of electrical interconnects. In the electrical domain, in order to operate at high frequency, the backplane topology has been changed from the simple shared bus to the complicated switched medium. However, the switched medium is an indirect network. It cannot support multicast/broadcast as effectively as the shared bus. Besides the additional latency of going through the intermediate switching nodes, signal routing introduces substantial delay and considerable system complexity. Alternatively, optics has been well known for its interconnect capability. Therefore, it has become imperative to investigate how to improve multiprocessing performance by utilizing optical interconnects. From the implementation standpoint, the existing optical technologies still cannot fulfill the intelligent functions that a switch fabric should provide as effectively as their electronic counterparts. Thus, an innovative optical technology that can provide sufficient bandwidth capacity, while at the same time, retaining the essential merits of the shared bus topology, is highly desirable for the multiprocessing performance improvement. In this paper, the optical centralized shared bus is proposed for use in the multiprocessing systems. This novel optical interconnect architecture not only utilizes the beneficial characteristics of optics, but also retains the desirable properties of the shared bus topology. Meanwhile, from the architecture standpoint, it fits well in the centralized shared-memory multiprocessing scheme. Therefore, a smooth migration with substantial multiprocessing performance improvement is expected. To prove the technical feasibility from the architecture standpoint, a conceptual emulation of the centralized shared-memory multiprocessing scheme is demonstrated on a generic PCI subsystem with an optical centralized shared bus.

The LSLE echocardiograph - Commercial hardware aboard Spacelab. [Life Sciences Laboratory Equipment

NASA Technical Reports Server (NTRS)

Schwarz, R.

1983-01-01

The Life Sciences Laboratory Equipment Echocardiograph, a commercial 77020AC Ultrasound Imaging System modified to meet NASA's spacecraft standards, is described. The assembly consists of four models: display and control, scanner, scan converter, and physioamplifiers. Four separate processors communicate over an IEE-488 bus, and the system has more than 6000 individual components on 35 printed circuit cards. Three levels of self test are provided: a short test during power up, a basic test initiated by a front panel switch, and interactive tests for specific routines. Default mode operation further enhances reliability. Modifications of the original system include the replacement of ac power supplies with dc to dc converters, a slide-out keyboard (to prevent accidental operation), Teflon insulated wire, and additional shielding for the ultrasound transducer cable.

A study of an arbiter function in the structures of a shared bus

NASA Astrophysics Data System (ADS)

Seck, J.-P.

The results of a comparative study of synchronous and asynchronous arbiters for managing user access to a shared bus is presented. The best available method is determined to be modular arbiter structures attached only to the decision module. Linear and circular arbitration strategies are examined for suitability for automatic decision-making. A multiple strategies arbiter scheme is devised, involving the superposition of various strategies of one sequential machine into another. It is then possible to modify the strategy on-line if the current strategy is ineffective. The utilization of a multiple structure of cascading arbiter devices is noted to be effective if response time is not a critical matter. Finally, attention is given to automatic circuit testing and fault detection. An example is furnished in terms of a management system for a shared memory in a multimicroprocessor structure.

Thermal Expert System (TEXSYS): Systems autonomy demonstration project, volume 2. Results

NASA Technical Reports Server (NTRS)

Glass, B. J. (Editor)

1992-01-01

The Systems Autonomy Demonstration Project (SADP) produced a knowledge-based real-time control system for control and fault detection, isolation, and recovery (FDIR) of a prototype two-phase Space Station Freedom external active thermal control system (EATCS). The Thermal Expert System (TEXSYS) was demonstrated in recent tests to be capable of reliable fault anticipation and detection, as well as ordinary control of the thermal bus. Performance requirements were addressed by adopting a hierarchical symbolic control approach-layering model-based expert system software on a conventional, numerical data acquisition and control system. The model-based reasoning capabilities of TEXSYS were shown to be advantageous over typical rule-based expert systems, particularly for detection of unforeseen faults and sensor failures. Volume 1 gives a project overview and testing highlights. Volume 2 provides detail on the EATCS testbed, test operations, and online test results. Appendix A is a test archive, while Appendix B is a compendium of design and user manuals for the TEXSYS software.

Thermal Expert System (TEXSYS): Systems autonomy demonstration project, volume 2. Results

NASA Astrophysics Data System (ADS)

Glass, B. J.

1992-10-01

The Systems Autonomy Demonstration Project (SADP) produced a knowledge-based real-time control system for control and fault detection, isolation, and recovery (FDIR) of a prototype two-phase Space Station Freedom external active thermal control system (EATCS). The Thermal Expert System (TEXSYS) was demonstrated in recent tests to be capable of reliable fault anticipation and detection, as well as ordinary control of the thermal bus. Performance requirements were addressed by adopting a hierarchical symbolic control approach-layering model-based expert system software on a conventional, numerical data acquisition and control system. The model-based reasoning capabilities of TEXSYS were shown to be advantageous over typical rule-based expert systems, particularly for detection of unforeseen faults and sensor failures. Volume 1 gives a project overview and testing highlights. Volume 2 provides detail on the EATCS testbed, test operations, and online test results. Appendix A is a test archive, while Appendix B is a compendium of design and user manuals for the TEXSYS software.

CSI Flight Computer System and experimental test results

NASA Technical Reports Server (NTRS)

Sparks, Dean W., Jr.; Peri, F., Jr.; Schuler, P.

1993-01-01

This paper describes the CSI Computer System (CCS) and the experimental tests performed to validate its functionality. This system is comprised of two major components: the space flight qualified Excitation and Damping Subsystem (EDS) which performs controls calculations; and the Remote Interface Unit (RIU) which is used for data acquisition, transmission, and filtering. The flight-like RIU is the interface between the EDS and the sensors and actuators positioned on the particular structure under control. The EDS and RIU communicate over the MIL-STD-1553B, a space flight qualified bus. To test the CCS under realistic conditions, it was connected to the Phase-0 CSI Evolutionary Model (CEM) at NASA Langley Research Center. The following schematic shows how the CCS is connected to the CEM. Various tests were performed which validated the ability of the system to perform control/structures experiments.

Fairness in optimizing bus-crew scheduling process.

PubMed

Ma, Jihui; Song, Cuiying; Ceder, Avishai Avi; Liu, Tao; Guan, Wei

2017-01-01

This work proposes a model considering fairness in the problem of crew scheduling for bus drivers (CSP-BD) using a hybrid ant-colony optimization (HACO) algorithm to solve it. The main contributions of this work are the following: (a) a valid approach for cases with a special cost structure and constraints considering the fairness of working time and idle time; (b) an improved algorithm incorporating Gamma heuristic function and selecting rules. The relationships of each cost are examined with ten bus lines collected from the Beijing Public Transport Holdings (Group) Co., Ltd., one of the largest bus transit companies in the world. It shows that unfair cost is indirectly related to common cost, fixed cost and extra cost and also the unfair cost approaches to common and fixed cost when its coefficient is twice of common cost coefficient. Furthermore, the longest time for the tested bus line with 1108 pieces, 74 blocks is less than 30 minutes. The results indicate that the HACO-based algorithm can be a feasible and efficient optimization technique for CSP-BD, especially with large scale problems.

Savannah River bus project

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

Summers, W.A.

1998-08-01

The H2Fuel Bus is the world`s first hybrid hydrogen electric transit bus. It was developed through a public/private partnership involving several leading technology and industrial organizations in the Southeast, with primary funding and program management provided by the Department of Energy. The primary goals of the project are to gain valuable information on the technical readiness and economic viability of hydrogen buses and to enhance the public awareness and acceptance of emerging hydrogen technologies. The bus has been operated by the transit agency in Augusta, Georgia since April, 1997. It employs a hybrid IC engine/battery/electric drive system, with onboard hydrogenmore » fuel storage based on the use of metal hydrides. Initial operating results have demonstrated an overall energy efficiency (miles per Btu) of twice that of a similar diesel-fueled bus and an operating range twice that of an all-battery powered electric bus. Tailpipe emissions are negligible, with NOx less than 0.2 ppm. Permitting, liability and insurance issues were addressed on the basis of extensive risk assessment and safety analyses, with the inherent safety characteristic of metal hydride storage playing a major role in minimizing these concerns. Future plans for the bus include continued transit operation and use as a national testbed, with potential modifications to demonstrate other hydrogen technologies, including fuel cells.« less

JPRS Report, Science & Technology, Japan, 27th Aircraft Symposium, Part 3

DTIC Science & Technology

1991-02-14

Kaoru Wakairo, et al.] Aircraft-Mounted Optical Data Bus (3): Bus Control Software, Performance Evaluation Test [Mitsumi Mayanägi, Minoru...Article by Hiroyasu Kawahara, Kaoru Wakairo, and Akira Watanabe, National Aerospace Laboratory; Tomoyuli Udagawa, Kengo Takeda, and Noboru Shobayashi...89 pp 518-521 [Article by Tadao Uchida, Mitsumi Mayanagi, Minoru Takizawa, Toshiharu Inagaki, Koki Hozumi, and Kazutoshi Ishikawa , National

49 CFR 665.11 - Testing requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... braking performance, Structural Integrity, Fuel Economy, Noise, and Emissions; (c) If the new bus model... testing facility shall develop a test plan for the testing of vehicles at the facility. The test plan...

Using Credit Cards To Pay Bus Fares in Phoenix

DOT National Transportation Integrated Search

1996-01-01

In 1991 the City of Phoenix Public Transit System, first in the nation to install magnetic card readers on the electronic fareboxes in its buses, implemented a program known as Bus Card Plus, which billed employers for trips made by employees using e...

Economic impacts of bus rapid transit in southeast Michigan.

DOT National Transportation Integrated Search

2015-12-01

In recent years, Bus Rapid Transit (BRT) has generated great interest across the United States. There are more than 20 BRT : systems in existence, and more are in the planning stage (including in Detroit). Within the next few years, BRT will be plann...

Preliminary concept for statewide intercity bus and rail transit system : priority corridor ranking and analysis.

DOT National Transportation Integrated Search

2009-03-01

This product summarizes the preliminary concept and priority corridors for development of a potential : statewide intercity bus and rail network. The concept is based upon the results of Tasks 1 through 5 of Texas : Department of Transportation Proje...

A uniform transit safety records system for the Commonwealth of Virginia.

DOT National Transportation Integrated Search

1981-01-01

This study was conceived as the first phase of a three-phase program to develop a safety data base for intracity bus transit. It involved reviewing the state of the art of general transportation safety management, examining the current intracity bus ...

Choosing a Motion Detector.

ERIC Educational Resources Information Center

Ballard, David M.

1990-01-01

Examines the characteristics of three types of motion detectors: Doppler radar, infrared, and ultrasonic wave, and how they are used on school buses to prevent students from being killed by their own school bus. Other safety devices cited are bus crossing arms and a camera monitor system. (MLF)

The Design of a Fault-Tolerant COTS-Based Bus Architecture

NASA Technical Reports Server (NTRS)

Chau, Savio N.; Alkalai, Leon; Burt, John B.; Tai, Ann T.

1999-01-01

In this paper, we report our experiences and findings on the design of a fault-tolerant bus architecture comprised of two COTS buses, the IEEE 1394 and the 12C. This fault-tolerant bus is the backbone system bus for the avionics architecture of the X2000 program at the Jet Propulsion Laboratory. COTS buses are attractive because of the availability of low cost commercial products. However, they are not specifically designed for highly reliable applications such as long-life deep-space missions. The X2000 design team has devised a multi-level fault tolerance approach to compensate for this shortcoming of COTS buses. First, the approach enhances the fault tolerance capabilities of the IEEE 1394 and 12 C buses by adding a layer of fault handling hardware and software. Second, algorithms are developed to enable the IEEE 1394 and the 12 C buses assist each other to isolate and recovery from faults. Third, the set of IEEE 1394 and 12 C buses is duplicated to further enhance system reliability. The X2000 design team has paid special attention to guarantee that all fault tolerance provisions will not cause the bus design to deviate from the commercial standard specifications. Otherwise, the economic attractiveness of using COTS will be diminished. The hardware and software design of the X2000 fault-tolerant bus are being implemented and flight hardware will be delivered to the ST4 and Europa Orbiter missions.

PV inverter performance and reliability: What is the role of the bus capacitor?

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

Flicker, Jack; Kaplar, Robert; Marinella, Matthew

In order to elucidate how the degradation of individual components affects the state of the photovoltaic inverter as a whole, we have carried out SPICE simulations to investigate the voltage and current ripple on the DC bus. The bus capacitor is generally considered to be among the least reliable components of the system, so we have simulated how the degradation of bus capacitors affects the AC ripple at the terminals of the PV module. Degradation-induced ripple leads to an increased degradation rate in a positive feedback cycle. Additionally, laboratory experiments are being carried out to ascertain the reliability of metallizedmore » thin film capacitors. By understanding the degradation mechanisms and their effects on the inverter as a system, steps can be made to more effectively replace marginal components with more reliable ones, increasing the lifetime and efficiency of the inverter and decreasing its cost per watt towards the US Department of Energy goals.« less

Environmental Technology Verification Test Report of Mobile Source Selective Catalytic Reduction, Johnson Matthey SCCRT, Version 1, Selective Catalytic Reduction Technology with a Catalyzed Continuously Regenerating Trap

EPA Science Inventory

The Johnson Matthey SCCRT, v.1 technology is a urea-based SCR system combined with a CCRT filter designed for on-highway light, medium, and heavy heavy-duty diesel, urban and non-urban, bus exhaust gas recirculation (EGR)-or non-EGR-equipped engines for use with commercial ultra-...

Apparatus, system and method for providing cryptographic key information with physically unclonable function circuitry

DOEpatents

Areno, Matthew

2015-12-08

Techniques and mechanisms for providing a value from physically unclonable function (PUF) circuitry for a cryptographic operation of a security module. In an embodiment, a cryptographic engine receives a value from PUF circuitry and based on the value, outputs a result of a cryptographic operation to a bus of the security module. The bus couples the cryptographic engine to control logic or interface logic of the security module. In another embodiment, the value is provided to the cryptographic engine from the PUF circuitry via a signal line which is distinct from the bus, where any exchange of the value by either of the cryptographic engine and the PUF circuitry is for communication of the first value independent of the bus.

Modular experimental platform for science and applications

NASA Technical Reports Server (NTRS)

Hill, A. S.

1984-01-01

A modularized, standardized spacecraft bus, known as MESA, suitable for a variety of science and applications missions is discussed. The basic bus consists of a simple structural arrangement housing attitude control, telemetry/command, electrical power, propulsion and thermal control subsystems. The general arrangement allows extensive subsystem adaptation to mission needs. Kits provide for the addition of tape recorders, increased power levels and propulsion growth. Both 3-axis and spin stabilized flight proven attitude control subsystems are available. The MESA bus can be launched on Ariane, as a secondary payload for low cost, or on the STS with a PAM-D or other suitable upper stage. Multi-spacecraft launches are possible with either booster. Launch vehicle integration is simple and cost-effective. The low cost of the MESA bus is achieved by the extensive utilization of existing subsystem design concepts and equipment, and efficient program management and test integration techniques.

Occupation exposed to road-traffic emissions and respiratory health among Congolese transit workers, particularly bus conductors, in Kinshasa: a cross-sectional study.

PubMed

Mbelambela, Etongola Papy; Hirota, Ryoji; Eitoku, Masamitsu; Muchanga, Sifa Marie Joelle; Kiyosawa, Hidenori; Yasumitsu-Lovell, Kahoko; Lawanga, Ontshick Leader; Suganuma, Narufumi

2017-03-20

Road-traffic emissions (RTE) induce adverse health effects, notably respiratory symptoms and respiratory diseases, as a result of pollutants deposited into the respiratory tract. The aim of this study was to evaluate the association between occupation groups of Congolese transit workers exposed to RTE, particularly bus conductors and respiratory health, in Kinshasa. A cross-sectional study was conducted from 2015 April 20 th to May 14 th , whose participants were bus conductors (n = 110), bus drivers (n = 107), taxi-motorcyclists (n = 102) and high school teachers (control group; n = 106). Subjects had completed the American Thoracic Society respiratory symptom questionnaire. Lung function test was performed by spirometry. Air pollutants levels of PM 2.5 , NO 2 and SO 2 were measured between 7:30 and 8:30 and 16:30-17:30 using a portable gas monitor. Multivariate analysis was performed to evaluate the association between occupation exposed to RTE and impaired pulmonary function, after adjustment by plausible confounders. The prevalence of mixed syndrome was 21.9% for bus conductors, 10.9% for bus drivers, 15.4% for taxi-motorcyclists and 7.1% for high school teachers with (p < 0.05). The risk of developing a mixed syndrome was seven times higher among bus conductors [OR = 7.64; 95% CI: 1.83-31.67; p < 0.05] than other groups. Additionally, the prevalence of respiratory syndromes increased with the duration of exposure. Occupation exposed to RTE is associated with impaired pulmonary function and the prevalence of respiratory symptoms among transit workers, especially bus conductors. Furthermore, this association increases with the duration of exposure suggesting the necessity to regulate these categories of occupations and to apply preventives measures.

Operational Results From a High Power Alternator Test Bed

NASA Technical Reports Server (NTRS)

Birchenough, Arthur; Hervol, David

2007-01-01

The Alternator Test Unit (ATU) in the Lunar Power System Facility (LPSF) located at the NASA Glenn Research Center (GRC) in Cleveland, Ohio was used to simulate the operating conditions and evaluate the performance of the ATU and its interaction with various LPSF components in accordance with the current Fission Surface Power System (FSPS) requirements. The testing was carried out at the breadboard development level. These results successfully demonstrated excellent ATU power bus characteristics and rectified user load power quality during steady state and transient conditions. Information gained from this work could be used to assist the design and primary power quality considerations for a possible future FSPS. This paper describes the LPSF components and some preliminary test results.

Speed limiter integrated fatigue analyzer (SLIFA) for speed and fatigue control on diesel engine truck and bus

NASA Astrophysics Data System (ADS)

Wahyudi, Haris; Pranoto, Hadi; Leman, A. M.; Sebayang, Darwin; Baba, I.

2017-09-01

Every second, the number of road traffic deaths is increased globally with millions more sustaining severe injuries and living with long-term adverse health consequences. Jakarta alone in year 2015 had recorded 556 people died due to road accidents, approximately reached 6.231 road accident cases. The identified major contributory factors of such unfortunate events are both driver fatigue and over speeding habit especially related to the driving of truck and bus. This paper presents the idea on how to control the electronic system from input fuel system of injection pump and the combustion chamber engine will control the valve solenoid in injection pump which can lock and fuel will stop for moment, and speed limit can be success, by using sensor heart rate we can input reduce speed limit when fatigue detection driver. Integration process this tool can be relevant when Speed Limiter Integrated Fatigue Analyser (SLIFA) trial in the diesel engine for truck and bus, the result of this research Speed Limiter Integrated Fatigue Analyser (SLIFA) able to control speed of diesel engine for truck and bus almost 30km/h, 60km/h, and until 70 km/h. The installation of the sensor heart rate as the input speed limit SLIFA would work when the driver is detected to be in the fatigue condition. We make Speed Limiter Integrated Fatigue Analyser (SLIFA) for control and monitoring system for diesel engine in truck and bus. Speed Limiter Integrated Fatigue Analyser (SLIFA) system can save the historical of the speed record, fatigue, rpm, and body temperature of the driver.

The Status of Spacecraft Bus and Platform Technology Development under the NASA ISPT Program

NASA Technical Reports Server (NTRS)

Anderson, David J.; Munk, Michelle M.; Pencil, Eric; Dankanich, John; Glaab, Louis; Peterson, Todd

2013-01-01

The In-Space Propulsion Technology (ISPT) program is developing spacecraft bus and platform technologies that will enable or enhance NASA robotic science missions. The ISPT program is currently developing technology in four areas that include Propulsion System Technologies (electric and chemical), Entry Vehicle Technologies (aerocapture and Earth entry vehicles), Spacecraft Bus and Sample Return Propulsion Technologies (components and ascent vehicles), and Systems/Mission Analysis. Three technologies are ready for near-term flight infusion: 1) the high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance; 2) NASA s Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6-7 kW throttle-able gridded ion system; and 3) Aerocapture technology development with investments in a family of thermal protection system (TPS) materials and structures; guidance, navigation, and control (GN&C) models of blunt-body rigid aeroshells; and aerothermal effect models. Two component technologies being developed with flight infusion in mind are the Advanced Xenon Flow Control System and ultralightweight propellant tank technologies. Future directions for ISPT are technologies that relate to sample return missions and other spacecraft bus technology needs like: 1) Mars Ascent Vehicles (MAV); 2) multi-mission technologies for Earth Entry Vehicles (MMEEV); and 3) electric propulsion. These technologies are more vehicles and mission-focused, and present a different set of technology development and infusion steps beyond those previously implemented. The Systems/Mission Analysis area is focused on developing tools and assessing the application of propulsion and spacecraft bus technologies to a wide variety of mission concepts. These inspace propulsion technologies are applicable, and potentially enabling for future NASA Discovery, New Frontiers, and sample return missions currently under consideration, as well as having broad applicability to potential Flagship missions. This paper provides a brief overview of the ISPT program, describing the development status and technology infusion readiness of in-space propulsion technologies in the areas of electric propulsion, Aerocapture, Earth entry vehicles, propulsion components, Mars ascent vehicle, and mission/systems analysis.

The status of spacecraft bus and platform technology development under the NASA ISPT program

NASA Astrophysics Data System (ADS)

Anderson, D. J.; Munk, M. M.; Pencil, E.; Dankanich, J.; Glaab, L.; Peterson, T.

The In-Space Propulsion Technology (ISPT) program is developing spacecraft bus and platform technologies that will enable or enhance NASA robotic science missions. The ISPT program is currently developing technology in four areas that include Propulsion System Technologies (electric and chemical), Entry Vehicle Technologies (aerocapture and Earth entry vehicles), Spacecraft Bus and Sample Return Propulsion Technologies (components and ascent vehicles), and Systems/Mission Analysis. Three technologies are ready for near-term flight infusion: 1) the high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance; 2) NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6-7 kW throttle-able gridded ion system; and 3) Aerocapture technology development with investments in a family of thermal protection system (TPS) materials and structures; guidance, navigation, and control (GN& C) models of blunt-body rigid aeroshells; and aerothermal effect models. Two component technologies being developed with flight infusion in mind are the Advanced Xenon Flow Control System and ultra-lightweight propellant tank technologies. Future directions for ISPT are technologies that relate to sample return missions and other spacecraft bus technology needs like: 1) Mars Ascent Vehicles (MAV); 2) multi-mission technologies for Earth Entry Vehicles (MMEEV); and 3) electric propulsion. These technologies are more vehicles and mission-focused, and present a different set of technology development and infusion steps beyond those previously implemented. The Systems/Mission Analysis area is focused on developing tools and assessing the application of propulsion and spacecraft bus technologies to a wide variety of mission concepts. These in-space propulsion technologies are applicable, and potentially enabling for future NASA Discovery, New Frontiers, and sample return missions currently under consideration, as well as having broad applicabilit- to potential Flagship missions. This paper provides a brief overview of the ISPT program, describing the development status and technology infusion readiness of in-space propulsion technologies in the areas of electric propulsion, Aerocapture, Earth entry vehicles, propulsion components, Mars ascent vehicle, and mission/systems analysis.

The Status of Spacecraft Bus and Platform Technology Development Under the NASA ISPT Program

NASA Technical Reports Server (NTRS)

Anderson, David J.; Munk, Michelle M.; Pencil, Eric J.; Dankanich, John; Glaab, Louis J.

2013-01-01

The In-Space Propulsion Technology (ISPT) program is developing spacecraft bus and platform technologies that will enable or enhance NASA robotic science missions. The ISPT program is currently developing technology in four areas that include Propulsion System Technologies (electric and chemical), Entry Vehicle Technologies (aerocapture and Earth entry vehicles), Spacecraft Bus and Sample Return Propulsion Technologies (components and ascent vehicles), and Systems/Mission Analysis. Three technologies are ready for near-term flight infusion: 1) the high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance 2) NASAs Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6-7 kW throttle-able gridded ion system and 3) Aerocapture technology development with investments in a family of thermal protection system (TPS) materials and structures guidance, navigation, and control (GN&C) models of blunt-body rigid aeroshells and aerothermal effect models. Two component technologies being developed with flight infusion in mind are the Advanced Xenon Flow Control System, and ultra-lightweight propellant tank technologies. Future direction for ISPT are technologies that relate to sample return missions and other spacecraft bus technology needs like: 1) Mars Ascent Vehicles (MAV) 2) multi-mission technologies for Earth Entry Vehicles (MMEEV) and 3) electric propulsion. These technologies are more vehicle and mission-focused, and present a different set of technology development and infusion steps beyond those previously implemented. The Systems/Mission Analysis area is focused on developing tools and assessing the application of propulsion and spacecraft bus technologies to a wide variety of mission concepts. These in-space propulsion technologies are applicable, and potentially enabling for future NASA Discovery, New Frontiers, and sample return missions currently under consideration, as well as having broad applicability to potential Flagship missions. This paper provides a brief overview of the ISPT program, describing the development status and technology infusion readiness of in-space propulsion technologies in the areas of electric propulsion, Aerocapture, Earth entry vehicles, propulsion components, Mars ascent vehicle, and mission/systems analysis.

Vehicle catalog : a compendium of vehicles and powertrain systems for bus rapid transit service

DOT National Transportation Integrated Search

2006-01-01

This report represents one part of an effort to provide information to the U.S. transit : authorities on activities related to Bus Rapid Transit (BRT). This document is prepared in : partnership with the Federal Transit Administration as part of a ...

Management Tools for Bus Maintenance: Current Practices and New Methods. Final Report.

ERIC Educational Resources Information Center

Foerster, James; And Others

Management of bus fleet maintenance requires systematic recordkeeping, management reporting, and work scheduling procedures. Tools for controlling and monitoring routine maintenance activities are in common use. These include defect and fluid consumption reports, work order systems, historical maintenance records, and performance and cost…

Aircraft Fiber-Optic Interconnect Systems Project.

DTIC Science & Technology

1980-08-15

W1 • 2 Grid Grid Figure 3-2. Receiver Schematic Diagram 3-5 .. .." - ": :- ’".. ..1 -n 13-P 430.... .... 1 II ..... .l3l I..... III .... .. . 3.1.3...the bus during conflicts caused by simultaneous requests. This in turn requires that the terminals using this protocol be " smart " to avoid a "central... UART RAM 2114 1Kx4l deoder decade? 8251 Data 4 buffeer zoo B Date bus -69 z S Control bus Peripheral decocler 5100 buffer I Kxr4 to SOL;, 5 se..onds PI

Discharging a DC bus capacitor of an electrical converter system

DOEpatents

Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

2014-10-14

A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

JPRS Report, Soviet Union, Political Affairs

DTIC Science & Technology

1988-11-28

in the development of its physical plant , improve designing , increase work quality, as well as strengthen order and organization in the sector...time, the Academy considers it essential to develop within its system a network of design bureaus and experimental plants . It must be said that almost...insufficiently developed physical plant . Over the last 10 years, not a single bus system has been built. For more than 6 years now, a trolley bus

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

Hansen, Timothy M.; Palmintier, Bryan; Suryanarayanan, Siddharth

As more Smart Grid technologies (e.g., distributed photovoltaic, spatially distributed electric vehicle charging) are integrated into distribution grids, static distribution simulations are no longer sufficient for performing modeling and analysis. GridLAB-D is an agent-based distribution system simulation environment that allows fine-grained end-user models, including geospatial and network topology detail. A problem exists in that, without outside intervention, once the GridLAB-D simulation begins execution, it will run to completion without allowing the real-time interaction of Smart Grid controls, such as home energy management systems and aggregator control. We address this lack of runtime interaction by designing a flexible communication interface, Bus.pymore » (pronounced bus-dot-pie), that uses Python to pass messages between one or more GridLAB-D instances and a Smart Grid simulator. This work describes the design and implementation of Bus.py, discusses its usefulness in terms of some Smart Grid scenarios, and provides an example of an aggregator-based residential demand response system interacting with GridLAB-D through Bus.py. The small scale example demonstrates the validity of the interface and shows that an aggregator using said interface is able to control residential loads in GridLAB-D during runtime to cause a reduction in the peak load on the distribution system in (a) peak reduction and (b) time-of-use pricing cases.« less

Assessing Liability and Legitimacy of School Transportation Services

ERIC Educational Resources Information Center

Ammon, Tim; Burns, Peggy

2011-01-01

Whenever a school district considers changing bus stops, bus routes, or bell times, the public reaction is often decidedly unequal to the magnitude of the changes proposed. Unfortunately, the severity of continued budget crises has compelled many school districts to make major changes to their transportation systems. While additional cuts in…

Princeton VLSI Project.

DTIC Science & Technology

1983-01-01

34 for these controllers: the remote words required appear On the system bus vithout having been requested, as if the controllers has ExtraSensory ... Perception .) In any case, the processor is not aware of the ESP controller (except for time delays); it operates as if it had a long bus linking it to all

76 FR 41323 - Over-the-Road Bus Accessibility Program Grants

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

..., authorized by Section 3038 of the Transportation Equity Act for the 21st Century (TEA-21). The OTRB... (TEA-21), Public Law 105-85 as amended by the Safe, Accountable, Flexible, Efficient, Transportation... bus services. These services are an important element of the U.S. transportation system. TEA-21...

Administration of Public School Transportation. School Business Administration Publication No. 6.

ERIC Educational Resources Information Center

California State Dept. of Education, Sacramento. Bureau of Administrative Services.

This document is intended to help California school boards in the selection of an appropriate and adequate student transportation system; and in the establishment, operation, and maintenance of a school bus fleet. Guidelines and pertinent State legislation are given for school bus purchase, maintenance, insurance and replacement; health…

49 CFR 665.5 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... kinetic energy for on-board storage and subsequent use. Retarder means a system other than the service brakes that slows a bus by dissipating kinetic energy. Seated load weight means the weight of the bus... which is capable of capturing, storing, and re-using energy. Major change in chassis design means, for...

49 CFR 665.5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... kinetic energy for on-board storage and subsequent use. Retarder means a system other than the service brakes that slows a bus by dissipating kinetic energy. Seated load weight means the weight of the bus... which is capable of capturing, storing, and re-using energy. Major change in chassis design means, for...

49 CFR 665.5 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... kinetic energy for on-board storage and subsequent use. Retarder means a system other than the service brakes that slows a bus by dissipating kinetic energy. Seated load weight means the weight of the bus... which is capable of capturing, storing, and re-using energy. Major change in chassis design means, for...

49 CFR 665.5 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... kinetic energy for on-board storage and subsequent use. Retarder means a system other than the service brakes that slows a bus by dissipating kinetic energy. Seated load weight means the weight of the bus... which is capable of capturing, storing, and re-using energy. Major change in chassis design means, for...

Theoretical Comparison of Fixed Route Bus and Flexible Route Subscription Bus Feeder Service in Low Density Areas

DOT National Transportation Integrated Search

1975-03-01

parametric variation of demand density was used to compare service level and cost of two alternative systems for providing low density feeder service. Supply models for fixed route and flexible route service were developed and applied to determine ra...

Sparkling Science Programs.

ERIC Educational Resources Information Center

Allen, Denise

1995-01-01

Reviews five compact disc-read only memory (CD-ROM) products and one video series that focus on science projects: (1) "Body Park" (Virtual Entertainment); (2) "The Magic School Bus Explores the Solar System" (Microsoft); (3) "The Magic School Bus Explores the Human Body" (Microsoft); (4) "Science Curriculum Assistance Program" (Demco); and (5)…

The modal transfer analysis by adding transport costs. Case study: The use of bus and private vehicle student Institut Teknologi Sumatera

NASA Astrophysics Data System (ADS)

Muliarto, H.; Alhamidi; Syahbandi, M.

2017-06-01

Since the last two years the Institut Teknologi Sumatera to accept new students in large numbers. Increasing the number of students is directly proportional to the increase of private vehicles that enter the campus it is not in line with the policy of the Institut Teknologi Sumatera as Smart, Friendly, and Forest Campus. Institut Teknologi Sumatera as Smart, Friendly, and Forest Campus fact has made some deal with mass public transport, Damri, to provide bus transportation to the Institut Teknologi Sumatera, but the number of bus users is still inferior to the number of private vehicle users. This study was conducted to see the modal transfer of the entire academic community ITERA, from private cars to public transport such as buses, with the addition of transportation costs in the form of parking rates. This study shows the dominant displacement can occur if the respondent charged parking fees of IDR 4.000. Besides the displacement mode of transportation from using private vehicles be using the bus can occur if Trans Lampung fix three systems including bus departure and arrival schedules, facility service providers that support, and the addition of the Bus Trans Lampung.

Classifying the Diversity of Bus Mapping Systems

NASA Astrophysics Data System (ADS)

Said, Mohd Shahmy Mohd; Forrest, David

2018-05-01

This study represents the first stage of an investigation into understanding the nature of different approaches to mapping bus routes and bus network, and how they may best be applied in different public transport situations. In many cities, bus services represent an important facet of easing traffic congestion and reducing pollution. However, with the entrenched car culture in many countries, persuading people to change their mode of transport is a major challenge. To promote this modal shift, people need to know what services are available and where (and when) they go. Bus service maps provide an invaluable element of providing suitable public transport information, but are often overlooked by transport planners, and are under-researched by cartographers. The method here consists of the creation of a map evaluation form and performing assessment of published bus networks maps. The analyses were completed by a combination of quantitative and qualitative data analysis of various aspects of cartographic design and classification. This paper focuses on the resulting classification, which is illustrated by a series of examples. This classification will facilitate more in depth investigations into the details of cartographic design for such maps and help direct areas for user evaluation.

Electric drive systems including smoothing capacitor cooling devices and systems

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

Dede, Ercan Mehmet; Zhou, Feng

An electric drive system includes a smoothing capacitor including at least one terminal, a bus bar electrically coupled to the at least one terminal, a thermoelectric device including a first side and a second side positioned opposite the first side, where the first side is thermally coupled to at least one of the at least one terminal and the bus bar, and a cooling element thermally coupled to the second side of the thermoelectric device, where the cooling element dissipates heat from the thermoelectric device.

Optical interconnection using polyimide waveguide for multichip module

NASA Astrophysics Data System (ADS)

Koyanagi, Mitsumasa

1996-01-01

We have developed a parallel processor system with 152 RISC processor chips specific for Monte-Carlo analysis. This system has the ring-bus architecture. The performance of several Gflops is expected in this system according to the computer simulation. However, it was revealed that the data transfer speed of the bus has to be increased more dramatically in order to further increase the performance. Then, we propose to introduce the optical interconnection into the parallel processor system to increase the data transfer speed of the buses. The double ringbus architecture is employed in this new parallel processor system with optical interconnection. The free-space optical interconnection arid the optical waveguide are used for the optical ring-bus. Thin polyimide film was used to form the optical waveguide. A relatively low propagation loss was achieved in the polyimide optical waveguide. In addition, it was confirmed that the propagation direction of signal light can be easily changed by using a micro-mirror.

Dynamic user data analysis and web composition technique using big data

NASA Astrophysics Data System (ADS)

Soundarya, P.; Vanitha, M.; Sumaiya Thaseen, I.

2017-11-01

In the existing system, a reliable service oriented system is built which is more important when compared with the traditional standalone system in the unpredictable internet service and it also a challenging task to build reliable web service. In the proposed system, the fault tolerance is determined by using the proposed heuristic algorithm. There are two kinds of strategies active and passive strategies. The user requirement is also formulated as local and global constraints. Different services are deployed in the modification process. Two bus reservation and two train reservation services are deployed along with hotel reservation service. User can choose any one of the bus reservation and specify their destination location. If corresponding destination is not available then automatic backup service to another bus reservation system is carried. If same, the service is not available then parallel service of train reservation is initiated. Automatic hotel reservation is also initiated based on the mode and type of travel of the user.

Bedside Ultrasonography as an Adjunct to Routine Evaluation of Acute Appendicitis in the Emergency Department

PubMed Central

Lam, Samuel H.F.; Grippo, Anthony; Kerwin, Chistopher; Konicki, P. John; Goodwine, Diana; Lambert, Michael J.

2014-01-01

Introduction Appendicitis is a common condition presenting to the emergency department (ED). Increasingly emergency physicians (EP) are using bedside ultrasound (BUS) as an adjunct diagnostic tool. Our objective is to investigate the test characteristics of BUS for the diagnosis of appendicitis and identify components of routine ED workup and BUS associated with the presence of appendicitis. Methods Patients four years of age and older presenting to the ED with suspected appendicitis were eligible for enrollment. After informed consent was obtained, BUS was performed on the subjects by trained EPs who had undergone a minimum of one-hour didactic training on the use of BUS to diagnose appendicitis. They then recorded elements of clinical history, physical examination, white blood cell count (WBC) with polymophonuclear percentage (PMN), and BUS findings on a data form. We ascertained subject outcomes by a combination of medical record review and telephone follow-up. Results A total of 125 subjects consented for the study, and 116 had adequate image data for final analysis. Prevalence of appendicitis was 40%. Mean age of the subjects was 20.2 years, and 51% were male. BUS was 100% sensitive (95% CI 87–100%) and 32% specific (95% CI 14–57%) for detection of appendicitis, with a positive predictive value of 72% (95% CI 56–84%), and a negative predictive value of 100% (95% CI 52–100%). Assuming all non-diagnostic studies were negative would yield a sensitivity of 72% and specificity of 81%. Subjects with appendicitis had a significantly higher occurrence of anorexia, nausea, vomiting, and a higher WBC and PMN count when compared to those without appendicitis. Their BUS studies were significantly more likely to result in visualization of the appendix, appendix diameter >6mm, appendix wall thickness >2mm, periappendiceal fluid, visualization of the appendix tip, and sonographic Mcburney’s sign (p<0.05). In subjects with diagnostic BUS studies, WBC, PMN, visualization of appendix, appendix diameter >6mm, appendix wall thickness >2mm, periappendiceal fluid were found to be predictors of appendicitis on logistic regression. Conclusion BUS is moderately useful for appendicitis diagnosis. We also identified several components in routine ED workup and BUS that are associated with appendicitis generating hypothesis for future studies. PMID:25493122

Portable Microcomputer Utilization for On-Line Pulmonary Testing

PubMed Central

Pugh, R.; Fourre, J.; Karetzky, M.

1981-01-01

A host-remote pulmonary function testing system is described that is flexible, non-dedicated, inexpensive, and readily upgradable. It is applicable for laboratories considering computerization as well as for those which have converted to one of the already available but restricted systems. The remote unit has an 8 slot bus for memory, input-output boards, and an A-D converter. It has its own terminal for manual input and display of computed and measured data which is transmitted via an acoustic modem to a larger microcomputer. The program modules are written in Pascal-Z and/or the supplied Z-80 macro assembler as external procedures.

American Fuel Cell Bus Project Evaluation. Second Report

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

Eudy, Leslie; Post, Matthew

2015-09-01

This report presents results of the American Fuel Cell Bus (AFCB) Project, a demonstration of fuel cell electric buses operating in the Coachella Valley area of California. The prototype AFCB was developed as part of the Federal Transit Administration's (FTA's) National Fuel Cell Bus Program. Through the non-profit consortia CALSTART, a team led by SunLine Transit Agency and BAE Systems developed a new fuel cell electric bus for demonstration. SunLine added two more AFCBs to its fleet in 2014 and another in 2015. FTA and the AFCB project team are collaborating with the U.S. Department of Energy (DOE) and DOE'smore » National Renewable Energy Laboratory to evaluate the buses in revenue service. This report summarizes the performance results for the buses through June 2015.« less

Decreasing the exhaust outlet temperatures on a class III bus with the lowest impact on the exhaust backpressure and the fuel consumption

NASA Astrophysics Data System (ADS)

Aslan, E.; Ozturk, Y.; Dileroglu, S.

2017-07-01

The focus of this study is to determine the most appropriate exhaust tail pipe form among three different type of designs with respect to their temperature loss efficiency for a 9.5m intercity bus equipped with an Euro VI diesel engine and an automated transmission. To provide lower temperatures at the exhaust outlet, mentioned designs were submitted on to a CFD simulation using Ansys Fluent 17.1, while for manufactured products, temperature measurement tests were conducted in an environmental chamber with Omega K-type thermocouples, and Flir T420 thermal camera was used to monitor outer surface temperature distributions to make a comparison between theoretical and practical results. In order to obtain these practical results, actual tests were performed in an environmental chamber with a constant ambient temperature during the vehicle exhaust emission system regeneration process. In conclusion, an exhaust tail pipe design with a diffuser having a circular contraction and expansion forms is designated since it was the most optimized option in terms of temperature loss efficiency, inconsiderable exhaust backpressure increase and manufacturing costs.

Programmable DMA controller

NASA Technical Reports Server (NTRS)

Hendry, David F. (Inventor)

1993-01-01

In a data system having a memory, plural input/output (I/O) devices and a bus connecting each of the I/O devices to the memory, a direct memory access (DMA) controller regulating access of each of the I/O devices to the bus, including a priority register storing priorities of bus access requests from the I/O devices, an interrupt register storing bus access requests of the I/O devices, a resolver for selecting one of the I/O devices to have access to the bus, a pointer register storing addresses of locations in the memory for communication with the one I/O device via the bus, a sequence register storing an address of a location in the memory containing a channel program instruction which is to be executed next, an ALU for incrementing and decrementing addresses stored in the pointer register, computing the next address to be stored in the sequence register, computing an initial contents of each of the register. The memory contains a sequence of channel program instructions defining a set up operation wherein the contents of each of the registers in the channel register is initialized in accordance with the initial contents computed by the ALU and an access operation wherein data is transferred on the bus between a location in the memory whose address is currently stored in the pointer register and the one I/O device enabled by the resolver.

High-Speed Ring Bus

NASA Technical Reports Server (NTRS)

Wysocky, Terry; Kopf, Edward, Jr.; Katanyoutananti, Sunant; Steiner, Carl; Balian, Harry

2010-01-01

The high-speed ring bus at the Jet Propulsion Laboratory (JPL) allows for future growth trends in spacecraft seen with future scientific missions. This innovation constitutes an enhancement of the 1393 bus as documented in the Institute of Electrical and Electronics Engineers (IEEE) 1393-1999 standard for a spaceborne fiber-optic data bus. It allows for high-bandwidth and time synchronization of all nodes on the ring. The JPL ring bus allows for interconnection of active units with autonomous operation and increased fault handling at high bandwidths. It minimizes the flight software interface with an intelligent physical layer design that has few states to manage as well as simplified testability. The design will soon be documented in the AS-1393 standard (Serial Hi-Rel Ring Network for Aerospace Applications). The framework is designed for "Class A" spacecraft operation and provides redundant data paths. It is based on "fault containment regions" and "redundant functional regions (RFR)" and has a method for allocating cables that completely supports the redundancy in spacecraft design, allowing for a complete RFR to fail. This design reduces the mass of the bus by incorporating both the Control Unit and the Data Unit in the same hardware. The standard uses ATM (asynchronous transfer mode) packets, standardized by ITU-T, ANSI, ETSI, and the ATM Forum. The IEEE-1393 standard uses the UNI form of the packet and provides no protection for the data portion of the cell. The JPL design adds optional formatting to this data portion. This design extends fault protection beyond that of the interconnect. This includes adding protection to the data portion that is contained within the Bus Interface Units (BIUs) and by adding to the signal interface between the Data Host and the JPL 1393 Ring Bus. Data transfer on the ring bus does not involve a master or initiator. Following bus protocol, any BIU may transmit data on the ring whenever it has data received from its host. There is no centralized arbitration or bus granting. The JPL design provides for autonomous synchronization of the nodes on the ring bus. An address-synchronous latency adjust buffer (LAB) has been designed that cannot get out of synchronization and needs no external input. Also, a priority-driven cable selection behavior has been programmed into each unit on the ring bus. This makes the bus able to connect itself up, according to a maximum redundancy priority system, without the need for computer intervention at startup. Switching around a failed or switched-off unit is also autonomous. The JPL bus provides a map of all the active units for the host computer to read and use for fault management. With regard to timing, this enhanced bus recognizes coordinated timing on a spacecraft as critical and addresses this with a single source of absolute and relative time, which is broadcast to all units on the bus with synchronization maintained to the tens of nanoseconds. Each BIU consists of up to five programmable triggers, which may be programmed for synchronization of events within the spacecraft of instrument. All JPL-formatted data transmitted on the ring bus are automatically time-stamped.

Power-balancing instantaneous optimization energy management for a novel series-parallel hybrid electric bus

NASA Astrophysics Data System (ADS)

Sun, Dongye; Lin, Xinyou; Qin, Datong; Deng, Tao

2012-11-01

Energy management(EM) is a core technique of hybrid electric bus(HEB) in order to advance fuel economy performance optimization and is unique for the corresponding configuration. There are existing algorithms of control strategy seldom take battery power management into account with international combustion engine power management. In this paper, a type of power-balancing instantaneous optimization(PBIO) energy management control strategy is proposed for a novel series-parallel hybrid electric bus. According to the characteristic of the novel series-parallel architecture, the switching boundary condition between series and parallel mode as well as the control rules of the power-balancing strategy are developed. The equivalent fuel model of battery is implemented and combined with the fuel of engine to constitute the objective function which is to minimize the fuel consumption at each sampled time and to coordinate the power distribution in real-time between the engine and battery. To validate the proposed strategy effective and reasonable, a forward model is built based on Matlab/Simulink for the simulation and the dSPACE autobox is applied to act as a controller for hardware in-the-loop integrated with bench test. Both the results of simulation and hardware-in-the-loop demonstrate that the proposed strategy not only enable to sustain the battery SOC within its operational range and keep the engine operation point locating the peak efficiency region, but also the fuel economy of series-parallel hybrid electric bus(SPHEB) dramatically advanced up to 30.73% via comparing with the prototype bus and a similar improvement for PBIO strategy relative to rule-based strategy, the reduction of fuel consumption is up to 12.38%. The proposed research ensures the algorithm of PBIO is real-time applicability, improves the efficiency of SPHEB system, as well as suite to complicated configuration perfectly.

DG Planning with Amalgamation of Operational and Reliability Considerations

NASA Astrophysics Data System (ADS)

Battu, Neelakanteshwar Rao; Abhyankar, A. R.; Senroy, Nilanjan

2016-04-01

Distributed Generation has been playing a vital role in dealing issues related to distribution systems. This paper presents an approach which provides policy maker with a set of solutions for DG placement to optimize reliability and real power loss of the system. Optimal location of a Distributed Generator is evaluated based on performance indices derived for reliability index and real power loss. The proposed approach is applied on a 15-bus radial distribution system and a 18-bus radial distribution system with conventional and wind distributed generators individually.

Modular Biometric Monitoring System

NASA Technical Reports Server (NTRS)

Chmiel, Alan J. (Inventor); Humphreys, Bradley T. (Inventor)

2017-01-01

A modular system for acquiring biometric data includes a plurality of data acquisition modules configured to sample biometric data from at least one respective input channel at a data acquisition rate. A representation of the sampled biometric data is stored in memory of each of the plurality of data acquisition modules. A central control system is in communication with each of the plurality of data acquisition modules through a bus. The central control system is configured to control communication of data, via the bus, with each of the plurality of data acquisition modules.

State-of-the-art cockpit design for the HH-65A helicopters

NASA Technical Reports Server (NTRS)

Castleberry, D. E.; Mcelreath, M. Y.

1982-01-01

In the design of a HH-65A helicopter cockpit, advanced integrated electronics systems technology was employed to achieve several important goals for this multimission aircraft. They were: (1) integrated systems operation with consistent and simplified cockpit procedures; (2) mission-task-related cockpit displays and controls, and (3) reduced pilot instrument scan effort with excellent outside visibility. The integrated avionics system was implemented to depend heavily upon distributed but complementary processing, multiplex digital bus technology, and multifunction CRT controls and displays. This avionics system was completely flight tested and will soon enter operational service with the Coast Guard.

GPS Spoofing Attack Characterization and Detection in Smart Grids

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

Blum, Rick S.; Pradhan, Parth; Nagananda, Kyatsandra

The problem of global positioning system (GPS) spoofing attacks on smart grids endowed with phasor measurement units (PMUs) is addressed, taking into account the dynamical behavior of the states of the system. First, it is shown how GPS spoofing introduces a timing synchronization error in the phasor readings recorded by the PMUs and alters the measurement matrix of the dynamical model. Then, a generalized likelihood ratio-based hypotheses testing procedure is devised to detect changes in the measurement matrix when the system is subjected to a spoofing attack. Monte Carlo simulations are performed on the 9-bus, 3-machine test grid to demonstratemore » the implication of the spoofing attack on dynamic state estimation and to analyze the performance of the proposed hypotheses test.« less

CHIPSat spacecraft design: significant science on a low budget

NASA Astrophysics Data System (ADS)

Janicik, Jeffrey; Wolff, Jonathan

2003-12-01

The Cosmic Hot Interstellar Plasma Spectrometer satellite (CHIPSat) was launched on January 12, 2003 and is successfully accomplishing its mission. CHIPS is NASA"s first-ever University-Class Explorer (UNEX) project, and is performed through a grant to the University of California at Berkeley (UCB) Space Sciences Laboratory (SSL). As a small start-up aerospace company, SpaceDev was awarded responsibility for a low-cost spacecraft and mission design, build, integration and test, and mission operations. The company leveraged past small satellite mission experiences to help design a robust small spacecraft system architecture. In addition, they utilized common industry hardware and software standards to facilitate design implementation, integration, and test of the bus, including the use of TCP/IP protocols and the Internet for end-to-end satellite communications. The approach called for a single-string design except in critical areas, the use of COTS parts to incorporate the latest proven technologies in commercial electronics, and the establishment of a working system as quickly as possible in order to maximize test hours prior to launch. Furthermore, automated ground systems were combined with table-configured onboard software to allow for "hands-off" mission operations. During nominal operations, the CHIPSat spacecraft uses a 3-axis stabilized zero-momentum bias "Nominal" mode. The secondary mode is a "Safehold" mode where fixed "keep-alive" arrays maintain enough power to operate the essential spacecraft bus in any attitude and spin condition, and no a-priori attitude knowledge is required to recover. Due to the omnidirectional antenna design, communications are robust in "Safehold" mode, including the transmission of basic housekeeping data at a duty cycle that is adjusted based on available solar power. This design enables the entire mission to be spent in "Observation Mode" with timed pointing files mapping the sky as desired unless an anomalous event upsets the health of the bus such that the spacecraft system toggles back to "Safehold". In all conditions, spacecraft operations do not require any time-critical operator involvement. This paper will examine the results of the first six months of CHIPSat on-orbit operations and measure them against the expectations of the aforementioned design architecture. The end result will be a "lessons learned" account of a 3-axis sun-pointing small spacecraft design architecture that will be useful for future science missions.

ESTL tracking and data relay satellite /TDRSS/ simulation system

NASA Technical Reports Server (NTRS)

Kapell, M. H.

1980-01-01

The Tracking Data Relay Satellite System (TDRSS) provides single access forward and return communication links with the Shuttle/Orbiter via S-band and Ku-band frequency bands. The ESTL (Electronic Systems Test Laboratory) at Lyndon B. Johnson Space Center (JSC) utilizes a TDRS satellite simulator and critical TDRS ground hardware for test operations. To accomplish Orbiter/TDRSS relay communications performance testing in the ESTL, a satellite simulator was developed which met the specification requirements of the TDRSS channels utilized by the Orbiter. Actual TDRSS ground hardware unique to the Orbiter communication interfaces was procured from individual vendors, integrated in the ESTL, and interfaced via a data bus for control and status monitoring. This paper discusses the satellite simulation hardware in terms of early development and subsequent modifications. The TDRS ground hardware configuration and the complex computer interface requirements are reviewed. Also, special test hardware such as a radio frequency interference test generator is discussed.

Analysis and design of a high power, digitally-controlled spacecraft power system

NASA Technical Reports Server (NTRS)

Lee, F. C.; Cho, B. H.

1990-01-01

The progress to date on the analysis and design of a high power, digitally controlled spacecraft power system is described. Several battery discharger topologies were compared for use in the space platform application. Updated information has been provided on the battery voltage specification. Initially it was thought to be in the 30 to 40 V range. It is now specified to be 53 V to 84 V. This eliminated the tapped-boost and the current-fed auto-transformer converters from consideration. After consultations with NASA, it was decided to trade-off the following topologies: (1) boost converter; (2) multi-module, multi-phase boost converter; and (3) voltage-fed push-pull with auto-transformer. A non-linear design optimization software tool was employed to facilitate an objective comparison. Non-linear design optimization insures that the best design of each topology is compared. The results indicate that a four-module, boost converter with each module operating 90 degrees out of phase is the optimum converter for the space platform. Large-signal and small-signal models were generated for the shunt, charger, discharger, battery, and the mode controller. The models were first tested individually according to the space platform power system specifications supplied by NASA. The effect of battery voltage imbalance on parallel dischargers was investigated with respect to dc and small-signal responses. Similarly, the effects of paralleling dischargers and chargers were also investigated. A solar array and shunt model was included in these simulations. A model for the bus mode controller (power control unit) was also developed to interface the Orbital replacement Unit (ORU) model to the platform power system. Small signal models were used to generate the bus impedance plots in the various operating modes. The large signal models were integrated into a system model, and time domain simulations were performed to verify bus regulation during mode transitions. Some changes have subsequently been incorporated into the models. The changes include the use of a four module boost discharger, and a new model for the mode controller, which includes the effects of saturation. The new simulations for the boost discharger show the improvement in bus ripple that can be achieved by phase-shifted operation of each of the boost modules.

Integrated High-Speed Torque Control System for a Robotic Joint

NASA Technical Reports Server (NTRS)

Davis, Donald R. (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Valvo, Michael C. (Inventor); Askew, R. Scott (Inventor)

2013-01-01

A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA).

Modular, thermal bus-to-radiator integral heat exchanger design for Space Station Freedom

NASA Technical Reports Server (NTRS)

Chambliss, Joe; Ewert, Michael

1990-01-01

The baseline concept is introduced for the 'integral heat exchanger' (IHX) which is the interface of the two-phase thermal bus with the heat-rejecting radiator panels. A direct bus-to-radiator heat-pipe integral connection replaces the present interface hardware to reduce the weight and complexity of the heat-exchange mechanism. The IHX is presented in detail and compared to the baseline system assuming certain values for heat rejection, mass per unit width, condenser capacity, contact conductance, and assembly mass. The spreadsheet comparison can be used to examine a variety of parameters such as radiator length and configuration. The IHX is shown to permit the reduction of panel size and system mass in response to better conductance and packaging efficiency. The IHX is found to be a suitable heat-rejection system for the Space Station Freedom because it uses present technology and eliminates the interface mechanisms.

An Inverter Packaging Scheme for an Integrated Segmented Traction Drive System

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

Su, Gui-Jia; Tang, Lixin; Ayers, Curtis William

The standard voltage source inverter (VSI), widely used in electric vehicle/hybrid electric vehicle (EV/HEV) traction drives, requires a bulky dc bus capacitor to absorb the large switching ripple currents and prevent them from shortening the battery s life. The dc bus capacitor presents a significant barrier to meeting inverter cost, volume, and weight requirements for mass production of affordable EVs/HEVs. The large ripple currents become even more problematic for the film capacitors (the capacitor technology of choice for EVs/HEVs) in high temperature environments as their ripple current handling capability decreases rapidly with rising temperatures. It is shown in previous workmore » that segmenting the VSI based traction drive system can significantly decrease the ripple currents and thus the size of the dc bus capacitor. This paper presents an integrated packaging scheme to reduce the system cost of a segmented traction drive.« less

Obstructive sleep apnea among express bus drivers in Malaysia: important indicators for screening.

PubMed

Yusoff, M Fadhli Mohd; Baki, Marina Mat; Mohamed, Norlen; Mohamed, A Sani; Yunus, M Razif Mohamad; Ami, Mazita; Othman, Ilhamah; Ishak, Azlan I

2010-12-01

Obstructive sleep apnea (OSA) has been identified as one of the significant risk factors for motor vehicle crashes (MVCs). In the interest of public safety, this study was conducted to determine the prevalence of OSA and its associated factors among express bus drivers in Malaysia. Identifying factors or conditions related with OSA is very important because they can be used as indicators to subject a person to a confirmatory diagnosis using polysomnography testing. Two hundred eighty-nine randomly selected express bus drivers from 5 express bus companies participated in the study. Information on demography, medical history, clinical symptoms, and signs of OSA were collected by a designated medical officer and the diagnosis of OSA was done based on the Apnea Hypopnoea Index (AHI) from polysomnography testing. Based on AHI, 128 (44.3%) subjects were diagnosed as having OSA with 83 (28.7%), 26 (9.0%), and 26 (6.6%) classified as mild, moderate, and severe OSA, respectively. Multiple logistic regression analysis results showed that age (odds ratio [OR] = 1.05, 95% confidence interval [CI] 1.01-1.09), snoring (OR = 3.54, 95% CI 1.91-6.57), body mass index (BMI; OR = 1.17, 95% CI 1.09-1.25), hypertension (OR = 1.87, 95% CI 1.02-3.40), and neck circumference (OR = 1.31, 95% CI 1.18-1.46) were significantly associated with OSA status. The results supported the need for identifying the risk group for OSA among express bus drivers and the need to diagnose them early for an early intervention.

An investigation of thermal comfort inside a bus during heating period within a climatic chamber.

PubMed

Pala, Uzeyir; Oz, H Ridvan

2015-05-01

By this study, it was aimed to define a testing and calculation model for thermal comfort assessment of a bus HVAC design and to compare effects of changing parameters on passenger's thermal comfort. For this purpose, a combined theoretical and experimental work during heating period inside a coach was carried out. The bus was left under 20 °C for more than 7 h within a climatic chamber and all heat sources were started at the beginning of a standard test. To investigate effects of fast transient conditions on passengers' physiology and thermal comfort, temperatures, air humidity and air velocities were measured. Human body was considered as one complete piece composed of core and skin compartments and the Transient Energy Balance Model developed by Gagge et al. in 1971 was used to calculate changes in thermal parameters between passenger bodies and bus interior environment. Depending on the given initial and environmental conditions, the graphs of passengers Thermal Sensation and Thermal Discomfort Level were found. At the end, a general mathematical model supported with a related experimental procedure was developed for the use of automotive HVAC engineers and scientists working on thermal comfort as a human dimension. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

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

NONE

Fieldbus technology has completed beta plant testing at Monsanto Co.`s Chocolate Bayou petrochemical complex at Alvin, Texas. The trial took place in a steam condensate recovery section of the Chocolate Bayou plant, which produces acrylonitrile, linear alkylbenzene, and a number of other petrochemical derivatives. Fieldbus is a plant communications network, or bus, that enables digital instruments to communicate with one another and with supervisory control systems. The fieldbus specification, written by the nonprofit organization Fieldbus Foundation, Austin, Texas, is called Foundation fieldbus. The beta tests at Chocolate Bayou successfully demonstrated fieldbus performance in a process control application.

Development of a prototype two-phase thermal bus system for Space Station

NASA Technical Reports Server (NTRS)

Myron, D. L.; Parish, R. C.

1987-01-01

This paper describes the basic elements of a pumped two-phase ammonia thermal control system designed for microgravity environments, the development of the concept into a Space Station flight design, and design details of the prototype to be ground-tested in the Johnson Space Center (JSC) Thermal Test Bed. The basic system concept is one of forced-flow heat transport through interface heat exchangers with anhydrous ammonia being pumped by a device expressly designed for two-phase fluid management in reduced gravity. Control of saturation conditions, and thus system interface temperatures, is accomplished with a single central pressure regulating valve. Flow control and liquid inventory are controlled by passive, nonelectromechanical devices. Use of these simple control elements results in minimal computer controls and high system reliability. Building on the basic system concept, a brief overview of a potential Space Station flight design is given. Primary verification of the system concept will involve testing at JSC of a 25-kW ground test article currently in fabrication.

Legal Self-Defense after a Bus Crash.

ERIC Educational Resources Information Center

Wright, Ron

1992-01-01

After a South Carolina school bus accident, involving the death of an automobile driver, the district was faced with a lawsuit. Advises school administrators not to rely on police authorities to gather all the evidence but to compile a thorough school-system accident report, written in close cooperation with a school attorney. Lists report…

76 FR 37393 - FY 2011 Discretionary Livability Funding Opportunity; Section 5309 Bus and Bus Facilities...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-27

... heating, solar panels, wind turbines, reflective roofing or paving materials, or other advanced... notification, FTA's system will notify the applicant if there are any problems with the submitted Supplemental... receive the validation message and to correct any problems that may have caused the application to be...

Mission Services Evolution Center Message Bus

NASA Technical Reports Server (NTRS)

Mayorga, Arturo; Bristow, John O.; Butschky, Mike

2011-01-01

The Goddard Mission Services Evolution Center (GMSEC) Message Bus is a robust, lightweight, fault-tolerant middleware implementation that supports all messaging capabilities of the GMSEC API. This architecture is a distributed software system that routes messages based on message subject names and knowledge of the locations in the network of the interested software components.