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1

MIL-STD-1553 programmable dual redundant remote terminal, bus controller, bus monitor, unit  

NASA Astrophysics Data System (ADS)

The performance, physical and electrical characteristics of the BUS-65600 Superhybrid are described. The Superhybrid is a programmable, fully compliant MIL-STD-1553 Dual Redundant Remote Terminal Unit (RTU), BUS Controller (BC) or BUS Monitor (BM). It requires the BUS-63125 Dual Redundant Monolithic Hybrid Transceiver or two BUS-63102 Universal Transceivers for MIL-STD-1553B or McAir sinusoidal applications. A discussion of the custom Monolithic LSI components implemented in the Superhybrid is included. The special features and capabilities are highlighted, along with special programming options which facilitate a broad array of applications. The BUS-65600 Superhybrid has a Direct Memory Access (DMA) Computer Interface plus necessary control lines which are also described in detail.

Friedman, S. N.

2

MIL-STD-1553 Dual Redundant Remote Terminal Unit, BUS Controller and BUS Monitor Superhybrid  

NASA Astrophysics Data System (ADS)

This paper describes the performance, physical, and electrical characteristics of the BUS-65600 Superhybrid. The Superhybrid is a programmable, fully compliant MIL-STD-1553 Dual Redundant Remote Terminal Unit (RTU), BUS Controller (BC) and BUS Monitor (BM). The BUS-65600 requires an external transceiver, clock, and transformers to provide a fully functional terminal interface. A discussion of the next generation CMOS Silicon-On-Sapphire (SOS) single monolithic chip RTU/BC/BM is included. The special features and capabilities, along with special package technologies are highlighted. The Superhybrid has a Direct Memory Access computer interface plus special control lines which are fully described.

Friedman, Steven N.

3

Effect of labor transfer times on labor flexibility in dual-resource queueing systems  

Microsoft Academic Search

A dual resource queueing system consisting of four machines in parallel is simulated in this study. This study differs from previous studies in that labor transfer delays are introduced. Experimental variables are labor transfer times, number of laborers, job sequence, and laborer assignment. Increasing the number of laborers decreases labor flexibility as was found in previous studies. Introducing transfer times,

M. Fruchtman; R. Gunther

1982-01-01

4

Interface For Dual-Channel MIL-STD-1553 Data Bus  

NASA Technical Reports Server (NTRS)

Digital electronic subsystem made of commercially available programmable logic arrays and discrete logic devices serves as interface between microprocessor and dual-channel MIL-STD-1553 data bus. Subsystem consumes only 800 mW of power. Provides flexibility in that it is controllable via firmware. Includes only two reading-and-writing ports: one for status and control signals, other for transmission and reception of data.

Davies, Bryan L.; Heaps, Timothy L.

1992-01-01

5

Maximizing Queueing Network Utility Subject to Stability: Greedy Primal-Dual Algorithm  

Microsoft Academic Search

We study a model of controlled queueing network, which operates and makes control decisions in discrete time. An underlying random network mode determines the set of available controls in each time slot. Each control decision \\

Alexander L. Stolyar

2005-01-01

6

Queue Applet  

NSDL National Science Digital Library

An applet that shows a queue in three different views: abstract, logical and physical. The abstract view visualizes how items are inserted into the tail end of the queue and removed from the head of the queue. The logical view represents the queue as a circular structure and shows how the head and tail pointers traverse from the end of the array to the start of the array. The physical view shows how the queue items are stored in the computer memory. The abstract view is shown by default, while the other two can be shown or hidden by the user. There is also a set of instructions on how to use the applet. The applet shows well how queues work and how they are implemented. The use of three different views support learning by showing the queue structure and queue operations in various abstraction levels. The user interface is simple and easy to use but maybe the use of other colours than just grey and black could make it more pleasant to watch. For example queue items with different colours might help in following of the animation. Also, it would be useful to have a possibility to insert some random default values into the queue. Recommended as lecture aide, standalone, self-study suppliment to tutorial or lecture.

Gilley, Shad

7

Degree Worksheet -Accounting/Dual (The only difference b/w Accounting and Dual is the number of major electives required: 1 for Accounting, 6 for Dual)  

E-print Network

Degree Worksheet - Accounting/Dual (The only difference b/w Accounting and Dual is the number Management BUS 340 Business Finance BUS 350 Business Law BUS 450 Strategic Management Degree Worksheet - ACC Worksheet - ACC-Dual Page 2 #12;

8

Analysis of the most appropriate electrical architecture and communication bus for the new dual voltage 14\\/42 V system  

Microsoft Academic Search

In this paper we analyze the advantages and disadvantages of the basic electrical architecture of the dual voltage 14\\/42 V system for vehicles proposed up to date. Certain functions of management of the electrical power and protection of the electrical system are also discussed such as the circuit protection, battery management system and fusing. In our analysis of circuit protection

Javier MaixC Altes; Ernest Gil Dolcet; B. P. Solorzano

2002-01-01

9

On Jockeying in Queues  

Microsoft Academic Search

There are numerous queueing situations in which those awaiting service may be allowed to make choices which affect the time spent in the service system. In such cases, it should be possible to formulate a \\

Ernest Koenigsberg

1966-01-01

10

Stacks, Queues and Tracks  

Microsoft Academic Search

This paper studies stack, queue, and track layouts of graph subdivisions. It is known that every graph has a 3-stack subdivision. The best known upper bound on the number of division vertices per edge in a 3-stack subdivision of an n-vertex graph G is improved from O(log n) to O(log minfsn(G);qn(G)g). This result reduces the question of whether queue-number is

David R. Wood

11

On RAM priority queues  

SciTech Connect

Priority queues are some of the most fundamental data structures. They are used directly for, say, task scheduling in operating systems. Moreover, they are essential to greedy algorithms. We study the complexity of priority queue operations on a RAM with arbitrary word size. We present exponential improvements over previous bounds, and we show tight relations to sorting. Our first result is a RAM priority queue supporting insert and extract-min operations in worst case time O(log log n) where n is the current number of keys in the queue. This is an exponential improvement over the O({radical}log n) bound of Redman and Willard from STOC`90. Our algorithm is simple, and it only uses AC{sup 0} operations, meaning that there is no hidden time dependency on the word size. Plugging this priority queue into Dijkstra`s algorithm gives an 0(mloglogm) algorithm for the single source shortest path problem on a graph with m edges, as compared with the previous O(m {radical} log m) bound based on Redman and Willard`s priority queue.

Thorup, M. [Univ. of Coepnhagen (Denmark)

1996-12-31

12

Priority Queues Page 1 Priority Queues  

E-print Network

to children and parents as seen in the previous chapter. Used as a priority queue ­ regular insertion based addressing, the formula would be Children(i) = 2i+1 and 2i+2 Parent(i) = (i-1)/2 NOTE: if we have the null path length of a binary tree to be the shortest path from the node to a node without two children

Allan, Vicki H.

13

Queueing for healthcare.  

PubMed

Patient queues are prevalent in healthcare and wait time is one measure of access to care. We illustrate Queueing Theory-an analytical tool that has provided many insights to service providers when designing new service systems and managing existing ones. This established theory helps us to quantify the appropriate service capacity to meet the patient demand, balancing system utilization and the patient's wait time. It considers four key factors that affect the patient's wait time: average patient demand, average service rate and the variation in both. We illustrate four basic insights that will be useful for managers and doctors who manage healthcare delivery systems, at hospital or department level. Two examples from local hospitals are shown where we have used queueing models to estimate the service capacity and analyze the impact of capacity configurations, while considering the inherent variation in healthcare. PMID:20703697

Palvannan, R Kannapiran; Teow, Kiok Liang

2012-04-01

14

A software bus for thread objects  

NASA Technical Reports Server (NTRS)

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.

Callahan, John R.; Li, Dehuai

1995-01-01

15

Job Queues and Wages  

Microsoft Academic Search

This paper uses job applications data to investigate the relationship between job queues and wage differentials. The main finding is that openings for jobs that pay the minimum wage attract more job applicants than jobs that pay either slightly more or slightly less than the minimum wage. This spike in the job application rate distribution suggests that ex ante rents

Harry J. Holzer; Lawrence F. Katz; Alan B. Krueger

1991-01-01

16

Queueing systems and networks. Models and applications  

Microsoft Academic Search

This article describes queueing systems and queueing networks which are successfully used for performance analysis of different systems such as computer, communications, transportation networks and manufacturing. It incorporates classical Markovian systems with exponential service times and a Poisson arrival process, and queueing systems with individual service. Oscillating queueing systems and queueing systems with Cox and Weibull service time distribution as

B. FILIPOWICZand J. KWIECIE

17

Bus Training Handbook.  

ERIC Educational Resources Information Center

This manual presents guidelines for teaching students with disabilities necessary skills for safe and independent travel on public buses. Six guidelines for teachers include: (1) participate in bus training; (2) use wise and intelligent judgment; (3) utilize the bus checklist; (4) know and teach bus rules; (5) know bus routes; and (6) know bus

Dorny, Audrea; Cole, ChiKay

18

A decentralized software bus based on IP multicas ting  

NASA Technical Reports Server (NTRS)

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.

Callahan, John R.; Montgomery, Todd

1995-01-01

19

Dynamics of Priority-Queue Networks  

NASA Astrophysics Data System (ADS)

In this Work-in-Progress paper, we study the dynamics of priority-queue networks by generalizing the interacting priority queue model of Oliveira and Vazquez [Physica A 388, 187 (2009)]. We show that the original AND-type protocol for interacting tasks is not scalable for the queue networks with more than two queues. We then introduce a scalable interaction protocol, an OR-type one, and examine the effects of the number of queues and the network topology on the waiting time dynamics of the priority-queue networks. We also study the effect of synchronicity in task executions to the waiting time dynamics in the priority-queue networks.

Min, Byung-Joon; Goh, Kwang-Il; Kim, In-Mook

20

Caudal Characteristic Curve of Queues.  

National Technical Information Service (NTIS)

Queues and other stochastic models having embedded Markov chains which, in the stable case, have a modified matrix geometric steady state probabilty vector, are discussed. The theory of matrix-geometric steady-state probabilities is outlined and the prope...

M. F. Neuts

1982-01-01

21

Message passing with queues and channels  

DOEpatents

In an embodiment, a reception thread receives a source node identifier, a type, and a data pointer from an application and, in response, creates a receive request. If the source node identifier specifies a source node, the reception thread adds the receive request to a fast-post queue. If a message received from a network does not match a receive request on a posted queue, a polling thread adds a receive request that represents the message to an unexpected queue. If the fast-post queue contains the receive request, the polling thread removes the receive request from the fast-post queue. If the receive request that was removed from the fast-post queue does not match the receive request on the unexpected queue, the polling thread adds the receive request that was removed from the fast-post queue to the posted queue. The reception thread and the polling thread execute asynchronously from each other.

Dozsa, Gabor J; Heidelberger, Philip; Kumar, Sameer; Ratterman, Joseph D; Steinmacher-Burrow, Burkhard

2013-02-19

22

Task allocation policies for State Dependent queues  

E-print Network

Consider a model of a dynamical queue with deterministic arrival and service rates, where the service rate depends on the server utilization history. This proposed queueing model occurs in many practical situations. for ...

Siew, Christine Chiu Hsia

2011-01-01

23

Factors influencing bus network design  

E-print Network

Bus network design and frequency setting, the highest level subproblems in the bus planning process, have long-term impacts on bus network performance. Improving network performance not only improves the attractiveness of ...

Loh, Zhen Xiang Kenneth

2014-01-01

24

Bus Programmable Slave Module.  

National Technical Information Service (NTIS)

A bus programmable slave module card for use in a computer control system is disclosed which comprises a master computer and one or more slave computer modules interfacing by means of a bus. Each slave module includes its own microprocessor, memory, and c...

W. A. Hall

1989-01-01

25

THE READING BUS \\  

Microsoft Academic Search

This paper focuses on the potential of parents to develop and use social capital generated through research activities organised by the Aberdeen Reading Bus. The Reading Bus project is a multi- agency partnership between schools, local libraries and colleagues working in adult learning, family learning and Community Learning and Development, with support and input from school liaison police officers, the

Kevin Stelfox; Rachel Shanks

26

Analysis on Realization of Sequential Queue  

NASA Astrophysics Data System (ADS)

Analyzed and introduced the sequential storage structure of the queue, detailed analyzed several specific methods for the circular queue to resolve the "false overflow", gave the algorithm descriptions in C of the corresponding basic operations of the queue, compared and analyzed each algorithm the time complexity and the space complexity, so as to complement and play a guiding role in the relevant chapters in "Data Structure" curriculum.

Wang, Min

27

MODELS FOR PREDICTING BUS DELAYS  

Microsoft Academic Search

The provision of accurate bus arrival time information to users is essential for improving the attractiveness of public transit service. Although bus-tracking technology provides real-time information to the control center about the location of a bus, there is a need to improve the prediction of bus travel time downstream from location of last observation in mixed traffic operations. Methods are

Ali Abdelfattah; Ata Khan

1998-01-01

28

Dynamics of priority-queue networks  

NASA Astrophysics Data System (ADS)

Recent application of priority queue models for human dynamics opened a way to study the human behavior under quantitative framework. Given the evident active engagement in social networking of individuals, dynamics of priority queues forming networks needs to be understood. Along this line, here we study the dynamics of priority-queue networks by generalizing the binary interacting priority queue model of Oliveira and Vazquez (OV). We found that the OV model with AND-type protocol for interacting tasks is in general not scalable for the queue networks with more than two queues, because the dynamics for interacting tasks become quickly frozen due to the priority conflicts. We then consider a scalable interaction protocol, an OR-type one, and examine the effects of the number of queues and the network topology on the waiting time dynamics of the priority-queue networks, finding that its distribution exhibits power-law tail in all cases considered, yet with exponents dependent on the network topology. We also show that when the tasks in the queue network are executed synchronously, priority conflicts affect the waiting time dynamics strongly, resulting in a different power law.

Min, Byungjoon; Goh, Kwang-Il; Kim, In-Mook

2009-03-01

29

Creative Bus Financing.  

ERIC Educational Resources Information Center

Alternative ways of financing school bus purchases include financing privately through contractors or commercial banks, financing through sources such as insurance companies and pension funds, leasing the buses, or contracting for transportation services. (Author/MLF)

Malone, Wade

1982-01-01

30

SCSI Communication Test Bus  

NASA Technical Reports Server (NTRS)

Small Computer System Interface (SCSI) communication test bus provides high-data-rate, standard interconnection enabling communication among International Business Machines (IBM) Personal System/2 Micro Channel, other devices connected to Micro Channel, test equipment, and host computer. Serves primarily as nonintrusive input/output attachment to PS/2 Micro Channel bus, providing rapid communication for debugger. Opens up possibility of using debugger in real-time applications.

Hua, Chanh V.; D'Ambrose, John J.; Jaworski, Richard C.; Halula, Elaine M.; Thornton, David N.; Heligman, Robert L.; Turner, Michael R.

1990-01-01

31

MIL-STD-1553 dynamic bus controller/remote terminal hybrid set  

NASA Astrophysics Data System (ADS)

This paper describes the performance, physical and electrical requirements of a Dual Redundant BUS Interface Unit (BIU) acting as a BUS Controller Interface Unit (BCIU) or Remote Terminal Unit (RTU) between a Motorola 68000 VME BUS and MIL-STD-1553B Multiplex Data Bus. A discussion of how the BIU Hybrid set is programmed, and operates as a BCIU or RTU, will be included. This paper will review Dynamic Bus Control and other Mode Code capabilities. The BIU Hybrid Set interfaces to a 68000 Microprocessor with a VME Bus using programmed I/O transfers. This special interface will be discussed along with the internal Dual Access Memory (4K x 16) used to support the data exchanges between the CPU and the BIU Hybrid Set. The hybrid set's physical size and power requirements will be covered. This includes the present Double Eurocard the BIU function is presently being offered on.

Friedman, S. N.

32

Task Release Control for Decision Making Queues  

Microsoft Academic Search

We consider the optimal duration allocation in a decision making queue. Decision making tasks arrive at a given rate to a human operator. The correctness of the decision made by human evolves as a sigmoidal function of the duration allocated to the task. Each task in the queue loses its value continuously. We elucidate on this trade-off and determine optimal

Vaibhav Srivastava; Ruggero Carli; Francesco Bullo; Cédric Langbort

2010-01-01

33

THE EFFECT OF CORRELATED ARRIVALS ON QUEUES  

Microsoft Academic Search

Using Markov renewal arrival processes, a study of the effect of serial correlations in the arrival process on the mean queueing performance has been done. We show that positive serial correlations may have major impact on the mean queue lengths (and consequently on other performance measures).

B. EDDY PATUWO; RALPH L. DISNEY; DONALD C. McNICKLE

1993-01-01

34

Bus supervision deployment strategies for improved bus service reliability  

E-print Network

Bus service reliability has always been a top concern for transit agencies and their customers. Unfortunately, there are several factors detrimental to reliable bus service. Outside influences such as weather, traffic, and ...

Pangilinan, Christopher Allan

2006-01-01

35

Multipurpose satellite bus (MPS)  

NASA Technical Reports Server (NTRS)

The Naval Postgraduate School Advanced Design Project sponsored by the Universities Space Research Association Advanced Design Program is a multipurpose satellite bus (MPS). The design was initiated from a Statement of Work (SOW) developed by the Defense Advanced Research Projects Agency (DARPA). The SOW called for a 'proposal to design a small, low-cost, lightweight, general purpose spacecraft bus capable of accommodating any of a variety of mission payloads. Typical payloads envisioned include those associated with meteorological, communication, surveillance and tracking, target location, and navigation mission areas.' The design project investigates two dissimilar missions, a meteorological payload and a communications payload, mated with a single spacecraft bus with minimal modifications. The MPS is designed for launch aboard the Pegasus Air Launched Vehicle (ALV) or the Taurus Standard Small Launch Vehicle (SSLV).

1991-01-01

36

Analysis and simulation of a fair queueing algorithm  

Microsoft Academic Search

We discuss gateway queueing algorithms and their role in controlling congestion in datagram networks. A fair queueing algorithm, based on an earlier suggestion by Nagle, is proposed. Analysis and simulations are used to compare this algorithm to other congestion control schemes. We find that fair queueing provides several important advantages over the usual first-come-first-serve queueing algorithm: fair allocation of bandwidth,

Alan J. Demers; Srinivasan Keshav; Scott J. Shenker

1989-01-01

37

Bus Annunciator System.  

National Technical Information Service (NTIS)

As a means of saving energy while minimizing the need for passenger cars, vans, and trucks in the Oak Ridge Y-12 Plant, buses are provided which operate along approximately 6 miles of in-plant roads. A bus annunciator system was developed, fabricated, and...

D. W. Carver, M. G. Duncan

1981-01-01

38

Augmented Thermal Bus  

NASA Technical Reports Server (NTRS)

The present invention is directed to an augmented thermal bus. In the present design a plurality of thermo-electric heat pumps are used to couple a source plate to a sink plate. Each heat pump is individually controlled by a model based controller. The controller coordinates the heat pumps to maintain isothermality in the source.

Schrage, Dean S. (Inventor)

1996-01-01

39

Bus annunciator system  

Microsoft Academic Search

As a means of saving energy while minimizing the need for passenger cars, vans, and trucks in the Oak Ridge Y-12 Plant, buses are provided which operate along approximately 6 miles of in-plant roads. A bus annunciator system was developed, fabricated, and installed which reduces the waiting time to near zero. The system consists of three separate devices: (1) an

D. W. Carver; M. G. Duncan

1981-01-01

40

Electric trolley bus - revisited  

Microsoft Academic Search

The electric trolley bus has never been dominant in the spectrum of public transit modes. Today, a total of 675 vehicles service 200 route-miles in 5 urban areas in the US. Trolley buses run in 4 cities in Canada and 2 in Mexico. Because of attitudes changing toward environmental impacts, riding comfort for passengers, preferential treatment for transit vehicles on

J. W. Schumann; B. J. Hanson

1979-01-01

41

Large scale queueing systems : asymptotics and insights  

E-print Network

Parallel server queues are a family of stochastic models useful in a variety of applications, including service systems and telecommunication networks. A particular application that has received considerable attention in ...

Goldberg, David Alan, Ph. D. Massachusetts Institute of Technology

2011-01-01

42

Performance Bounds for Scheduling Queueing Networks  

E-print Network

The goal of this paper is to assess the improvement in performance that might' be achieved by optimally scheduling a multiclass open queueing network. A stochastic process is defined whose steady-state mean value is less ...

Ou, Jihong

43

Rate-Controlled Static-Priority Queueing  

Microsoft Academic Search

We propose a new service discipline, called the Rate- Controlled Static-Priority(RCSP)queueingdiscipline, that can provide throughput, delay, delay jitter, and loss free guarantees in a connection-orientedpacket-switching net- work. Previously proposed solutions are based on either a time-framing strategy, or a sorted priority queue mecha- nism. Time-framing schemes suffer from the dependencies they introduce between the queueing delay and the granu- larity

Hui Zhang; Domenico Ferrari

1993-01-01

44

Model Predictive Control for the Acquisition Queue and Related Queueing Networks  

E-print Network

Predictive Control (MPC) is a well established method in control theory and engineering practice. It is often the method of choice for systems that need to be controlled in view of constraints. The main idea of MPCModel Predictive Control for the Acquisition Queue and Related Queueing Networks Johan S.H. van

Nazarathy, Yoni

45

THE QUEUE-READ QUEUE-WRITE PRAM MODEL: ACCOUNTING FOR CONTENTION IN PARALLEL ALGORITHMS  

E-print Network

) parallel random access machine (pram) model, which permits concurrent reading and writing to shared by reading and writing locations in a shared memory. Existing pram models can be distinguished by their rulesTHE QUEUE-READ QUEUE-WRITE PRAM MODEL: ACCOUNTING FOR CONTENTION IN PARALLEL ALGORITHMS PHILLIP B

Gibbons, Phillip B.

46

Optimal queue length for orthopaedic surgery with surgeon-specific queues and maximum waiting time  

Microsoft Academic Search

Lengthened waiting times to surgical operations lead to a diminished patient satisfaction, deteriorated medical quality and increased costs. In order to avoid long queues, authorities have enacted care guarantees that define the maximum waiting time to services. In this study, the effect of queue length and care guarantee of maximum waiting time on OR productivity is discussed from a case

Antti Peltokorpi; Juha-Matti Lehtonen; Paulus Torkki; Teemu Moilanen

47

A Framework for Alternate Queueing: Towards Traffic Management by P C-UNIX Based Routers  

Microsoft Academic Search

Queueing is an essential element of traffic manage- ment, but the only queueing discipline used in traditional UNIX systems is simple FIFO queueing. This paper de- scribes ALTQ, a queueing framework that allows the use of a set of queueing disciplines. We investigate the is- sues involved in designing a generic queueing framework as well as the issues involved in

Kenjiro Cho

1998-01-01

48

Maximally Stabilizing Task Release Control Policy for a Dynamical Queue  

E-print Network

In this technical note, we introduce a model of dynamical queue, in which the service time depends on the server utilization history. The proposed queueing model is motivated by widely accepted empirical laws describing ...

Savla, Ketan

49

Euro Data Bus  

SciTech Connect

With the disintegration of the Soviet Union and the opening of the Iron Curtain, a downsizing of the Defense Establishment in the West is occurring, causing industry to look for opportunities where technology used for military applications can be applied to meet former East Block countries. Among these requirements has been the urgent desire of the people in former East Block countries for access to Western media which had been denied them, and has led to numerous opportunities for the implementation of Cable Television (CATV) systems. In addition, there are also requirements for utility metering for electricity, gas, water, heat, etc. which had previously been provided to the population by the Government at little or no cost. EWT of Augsburg, Germany, previously a subcontractor to ASEC on military security system projects, who has a subsidiary, TSS, which is a prominent CATV systems house, requested ASEC to provide a system which can provide utility meter reading and other control and monitoring services utilizing CATV. Working with CableBus Systems Corporation, a CATV data communications supplier and various utility meter manufacturers, ASEC, as the System Integrator, has developed a utilities monitoring system. This system. in cooperation with EWT, is being marketed and sold in Europe as EURO DATA BUS. This paper describes EURO DATA BUS and its applications, as well as the actual system designs for two pilot applications. One system is oriented at Utility Meter Reading and Demand side Management primarily, but will also be used to demonstrate other system capabilities such as security and fire alarm monitoring, etc. The design is therefore quite straightforward and {open_quotes}standard{close_quotes}. The second system has more of an industrial orientation and involves the monitoring and load control for a Municipal Electric Utility. While well within the capabilities of the system to accomplish, a more customized design was required to meet these requirements.

Engel, H.E.; Hall, J.R. II; Schrock, C.B.

1995-12-31

50

Bridging genetic networks and queueing theory  

NASA Astrophysics Data System (ADS)

One of the main challenges facing biology today is the understanding of the joint action of genes, proteins and RNA molecules, interwoven in intricate interdependencies commonly known as genetic networks. To this end, several mathematical approaches have been introduced to date. In addition to developing the analytical tools required for this task anew, one can utilize knowledge found in existing disciplines, specializing in the representation and analysis of systems featuring similar aspects. We suggest queueing theory as a possible source of such knowledge. This discipline, which focuses on the study of workloads forming in a variety of scenarios, offers an assortment of tools allowing for the derivation of the statistical properties of the inspected systems. We argue that a proper adaptation of modeling techniques and analytical methods used in queueing theory can contribute to the study of genetic regulatory networks. This is demonstrated by presenting a queueing-inspired model of a genetic network of arbitrary size and structure, for which the probability distribution function is derived. This model is further applied to the description of the lac operon regulation mechanism. In addition, we discuss the possible benefits stemming for queueing theory from the interdisciplinary dialogue with molecular biology-in particular, the incorporation of various dynamical behaviours into queueing networks.

Arazi, Arnon; Ben-Jacob, Eshel; Yechiali, Uri

2004-02-01

51

KalmanQueue: An Adaptive Approach to Virtual Queuing  

E-print Network

are not significantly affected and (2) maximum waiting time for QuickPass users is small. To build a solid foundation then develop two QuickPass systems, GhostQueue and KalmanQueue. GhostQueue is an intuitive and simple system.1 Computer Simulation of Long Line Model Plus Noise . . . . . . . 10 7 Mixing the Two Lines 11 8 Ghost

Morrow, James A.

52

Dynamic queue behavior in networks with window protocols  

Microsoft Academic Search

In this paper we employ a deterministic analysis technique to characterize the dynamic queueing aspects of window protocols. The deterministic behavior of these protocols and the deterministic influence of the resources along the physical path are explicitly considered in the evaluation of path queue behavior. Transient and steady state queue behavior of fixed and sliding window protocols are investigated. We

John G. Waclawsky; Ashok K. Agrawala

1990-01-01

53

Priority queues: Where social justice and equity collide  

Microsoft Academic Search

Multilevel queues have become a common feature in service sector contexts, examples include ‘guest lists’ at night clubs and ‘priority boarding’ in air travel. This paper explores multilevel queueing systems within the context of theme parks, specifically their effects on consumers. Previous studies have focussed on single line systems and multilevel queues remain under-researched. By applying social justice and equity

Matthew Alexander; Andrew MacLaren; Kevin O’Gorman; Christopher White

54

Cycle time variability for a network under two queueing disciplines  

E-print Network

A network of three single-server queues is investigated. Performance of two queueing disciplines is compared on the basis of the mean and variance of the network cycle time. The two queueing disciplines are first-in-system first-out (FISFO...

Vasquez Pariente, Marta Irene

2012-06-07

55

BUS high current battery model  

Microsoft Academic Search

Attention is given to an empirical model for voltage and equivalent series resistance (ESR) developed for lead acid batteries used as a pulsed power source. The Battery Upgraded Supply (BUS) for Elgin Air Force Base is a 5 MA, 500 MJ inductive power supply charged by batteries for use as a railgun power supply. BUS is designed to reach peak

J. P. Kajs; R. C. Zowarka

1993-01-01

56

Improving School Bus Driver Performance.  

ERIC Educational Resources Information Center

This reference source is intended to assist the school bus driver training instructor in course preparation. Instructional units for program planning each contain pertinent course questions, a summary, and evaluation questions. Unit 1, "Introduction to the School Bus Driver Training Program," focuses on basic course objectives and requirements and…

Farmer, Ernest

57

Hybrid shuttle bus using ultracapacitors  

Microsoft Academic Search

The Electric Vehicle Institute, College of Technology at Bowling Green State University in Ohio has developed a diesel\\/electric hybrid propulsion system. This system has been installed in a 27 passenger shuttle bus. This bus has recently been put into shuttle service on campus in order to collect application data, receive feedback from professional operators and provide a demonstration of the

Jeff Major

2005-01-01

58

Tennessee Minimum School Bus Standards.  

ERIC Educational Resources Information Center

The School Bus Specifications and Procedures adopted by the 2000 National Conference on School Transportation and the Federal Motor Vehicle Safety Standards (FMVSS) were used as guides by the Tennessee State Board of Education Pupil Transportation Advisory Committee in developing the revised minimum specifications for school bus chassis and school…

Tennessee State Board of Education, 2004

2004-01-01

59

Hybrid Electric Transit Bus  

NASA Technical Reports Server (NTRS)

A government, industry, and university cooperative is developing an advanced hybrid electric city transit bus. Goals of this effort include doubling the fuel economy compared to current buses and reducing emissions to one-tenth of current EPA standards. Unique aspects of the vehicle's power system include the use of ultra-capacitors as an energy storage system, and a planned natural gas fueled turbogenerator developed from a small jet engine. Power from both the generator and energy storage system is provided to a variable speed electric motor attached to the rear axle. At over 15000 kg gross weight, this is the largest vehicle of its kind ever built using ultra-capacitor energy storage. This paper describes the overall power system architecture, the evolution of the control strategy, and its performance over industry standard drive cycles.

Viterna, Larry A.

1997-01-01

60

Waiting time dynamics of priority-queue networks  

NASA Astrophysics Data System (ADS)

We study the dynamics of priority-queue networks, generalizations of the binary interacting priority-queue model introduced by Oliveira and Vazquez [Physica A 388, 187 (2009)]. We found that the original AND-type protocol for interacting tasks is not scalable for the queue networks with loops because the dynamics becomes frozen due to the priority conflicts. We then consider a scalable interaction protocol, an OR-type one, and examine the effects of the network topology and the number of queues on the waiting time distributions of the priority-queue networks, finding that they exhibit power-law tails in all cases considered, yet with model-dependent power-law exponents. We also show that the synchronicity in task executions, giving rise to priority conflicts in the priority-queue networks, is a relevant factor in the queue dynamics that can change the power-law exponent of the waiting time distribution.

Min, Byungjoon; Goh, K.-I.; Kim, I.-M.

2009-05-01

61

Queue lengths and workloads in polling systems  

E-print Network

We consider a polling system: a queueing system of $N\\ge 1$ queues with Poisson arrivals $Q_1,...,Q_N$ visited in a cyclic order (with or without switchover times) by a single server. For this system we derive the probability generating function $\\mathscr Q(\\cdot)$ of the joint queue length distribution at an arbitrary epoch in a stationary cycle, under no assumptions on service disciplines. We also derive the Laplace-Stieltjes transform $\\mathscr W(\\cdot)$ of the joint workload distribution at an arbitrary epoch. We express $\\mathscr Q$ and $\\mathscr W$ in the probability generating functions of the joint queue length distribution at visit beginnings, ${\\mathscr V}_{b_i}(\\cdot)$, and visit completions, ${\\mathscr V}_{c_i}(\\cdot)$, at $Q_i$, $i=1,...,N$. It is well known that ${\\mathscr V}_{b_i}$ and ${\\mathscr V}_{c_i}$ can be computed in a broad variety of cases. Furthermore, we establish a workload decomposition result.

Boxma, Onno; Kosinski, Kamil Marcin

2011-01-01

62

Cooperative Cognitive Radio with Priority Queueing Analysis  

Microsoft Academic Search

In this paper, we model the hierarchical structures inherent in cognitive radio networks as the priority queueing system in which primary users interact with the highest priority and secondary users belong to the lowest priority class. In a M\\/G\\/l system containing one primary user and multiple secondary users, we obtain analytical forms of delay and throughput for different users with

Caoxie Zhang; Xinbing Wang; Jun Li

2009-01-01

63

Reducing transit bus emissions: Alternative fuels or traffic operations?  

NASA Astrophysics Data System (ADS)

In this study, we simulated the operations and greenhouse gas (GHG) emissions of transit buses along a busy corridor and quantified the effects of two different fuels (conventional diesel and compressed natural gas) as well as a set of driving conditions on emissions. Results indicate that compressed natural gas (CNG) reduces GHG emissions by 8-12% compared to conventional diesel, this reduction could increase to 16% with high levels of traffic congestion. However, the benefits of switching from conventional diesel to CNG are less apparent when the road network is uncongested. We also investigated the effects of bus operations on emissions by applying several strategies such as transit signal priority (TSP), queue jumper lanes, and relocation of bus stops. Results show that in congested conditions, TSP alone can reduce GHG emissions by 14% and when combined with improved technology; a reduction of 23% is achieved. The reduction benefits are even more apparent when other transit operational improvements are combined with TSP. Finally a sensitivity analysis was performed to investigate the effect of operational improvements on emissions under varying levels of network congestion. We observe that under “extreme congestion”, the benefits of TSP decrease.

Alam, Ahsan; Hatzopoulou, Marianne

2014-06-01

64

High-Speed Ring Bus  

NASA Technical Reports Server (NTRS)

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.

Wysocky, Terry; Kopf, Edward, Jr.; Katanyoutananti, Sunant; Steiner, Carl; Balian, Harry

2010-01-01

65

Main Entrances Free City Bus Stops  

E-print Network

647 EASBY ROAD A647 A647 25 26 27 B Main Entrances Free City Bus Stops Controlled parking areas Information B Bus Stops B Main Entrances Free City Bus Stops Controlled parking areas (permit holders only B Main Entrances Free City Bus Stops Controlled parking areas (permit holders only)P Visitor car

Magee, Derek

66

Bus Serialization for Reducing Power Consumption  

Microsoft Academic Search

yyy Shared-bus chip multiprocessors require buses with long wires. The portion of power consumed in wires relatively increases with device scaling. In this paper, we advocate the use of bus serialization to reduce bus power consumption. Bus serialization decreases the number of wires, and increases the pitch between wires. The wider pitch decreases the coupling capacitances of wires, and consequently

Naoya Hatta; Niko Demus Barli; Chitaka Iwama; Luong Dinh Hung; Daisuke Tashiro; Shuichi Sakai; Hidehiko Tanaka

2006-01-01

67

BUS DISPATCHING AT TIMED TRANSFER TRANSIT STATIONS  

E-print Network

BUS DISPATCHING AT TIMED TRANSFER TRANSIT STATIONS USING BUS TRACKING TECHNOLOGY May 26, 1999 Maged BUS TRACKING TECHNOLOGY ABSTRACT A timed transfer terminal synchronizes the arrival of incoming of Southern California Los Angeles, CA 90089-0193 #12;BUS DISPATCHING AT TIMED TRANSFER TRANSIT STATIONS USING

Dessouky, Maged

68

Ring Buffered Network Bus  

NASA Technical Reports Server (NTRS)

This report describes the research effort to demonstrate the integration of a data sharing technology, Ring Buffered Network Bus, in development by Dryden Flight Research Center, with an engine simulation application, the Java Gas Turbine Simulator, in development at the University of Toledo under a grant from the Glenn Research Center. The objective of this task was to examine the application of the RBNB technologies as a key component in the data sharing, health monitoring and system wide modeling elements of the NASA Aviation Safety Program (AVSP) [Golding, 1997]. System-wide monitoring and modeling of aircraft and air safety systems will require access to all data sources which are relative factors when monitoring or modeling the national airspace such as radar, weather, aircraft performance, engine performance, schedule and planning, airport configuration, flight operations, etc. The data sharing portion of the overall AVSP program is responsible for providing the hardware and software architecture to access and distribute data, including real-time flight operations data, among all of the AVSP elements. The integration of an engine code capable of numerically "flying" through recorded flight paths and weather data using a software tool that allows for distributed access of data to this engine code demonstrates initial steps toward building a system capable of monitoring and modeling the National Airspace.

1997-01-01

69

Simple spectral Representations for the M\\/M\\/1 Queue  

Microsoft Academic Search

This paper shows that certain basic descriptions of the time-dependent behavior of the M\\/M\\/1 queue have very simple representations as mixtures of exponentials. In particular, this is true for the busy-period density, the probability that the server is busy starting at zero, the expected queue length starting at zero and the autocorrelation function of the stationary queue-length process. In each

Joseph Abate; Ward Whitt

1988-01-01

70

Enhanced queue status reporting scheme on PON  

NASA Astrophysics Data System (ADS)

In the passive optical network (PON) system, the optical line terminal (OLT) assigns bandwidth to each optical network unit (ONU) in accordance with the traffic condition at an ONU. The OLT needs to predict the remote ONU's required bandwidth. We give consideration about the error margin in the bandwidth prediction, and point out a problem in the future high-bit-rate PON and propose an enhanced queue status reporting method.

Mukai, Hiroaki; Yokotani, Tetsuya; Seno, Shoichiro; Motoshima, Kuniaki

2007-06-01

71

The Average Velocity in a Queue  

ERIC Educational Resources Information Center

A number of cars drive along a narrow road that does not allow overtaking. Each driver has a certain maximum speed at which he or she will drive if alone on the road. As a result of slower cars ahead, many cars are forced to drive at speeds lower than their maximum ones. The average velocity in the queue offers a non-trivial example of a mean…

Frette, Vidar

2009-01-01

72

Forecast analysis of optical waveguide bus performance  

NASA Technical Reports Server (NTRS)

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.

Ledesma, R.; Rourke, M. D.

1979-01-01

73

Flow-Level Fair Queue Management Scheme Stabilizing Buffer Utilization  

NASA Astrophysics Data System (ADS)

Multimedia traffic on the Internet is rapidly increasing with the advent of broadband networks. However, the Best-Effort (BE) service used with Internet Protocol (IP) networking was never intended to guarantee Quality of Service (QoS) for each user. Therefore, the realization of QoS guarantees has become a very important issue. Previously, we have proposed a queue management scheme, called Dual Metrics Fair Queuing (DMFQ), to improve fairness and to guarantee QoS. DMFQ improves fairness and throughput by considering the amount of instantaneous and historical network resources consumed per flow. In addition, DMFQ has characteristics of high speed and high scalability because it is hardware oriented. However, DMFQ may be unable to adapt to network fluctuations, given that it has static setup parameters. Moreover, DMFQ is unable to support a multiclass environment. In this paper, we propose a new buffer management scheme based on DMFQ that can adapt flexibly to network conditions and can provide classified services. The proposed scheme stabilizes buffer utilization within a fixed range by controlling the buffer threshold, which affects the calculated packet discard probability. Moreover, by applying the proposed scheme to Differentiated Services (DiffServ), we achieve prioritized buffer management.

Shinohara, Yusuke; Yamagaki, Norio; Tode, Hideki; Murakami, Koso

74

46 CFR 183.324 - Dual voltage generators.  

Code of Federal Regulations, 2012 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) ELECTRICAL...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2012-10-01

75

46 CFR 183.324 - Dual voltage generators.  

Code of Federal Regulations, 2010 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) ELECTRICAL...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2010-10-01

76

46 CFR 183.324 - Dual voltage generators.  

Code of Federal Regulations, 2013 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) ELECTRICAL...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2013-10-01

77

46 CFR 183.324 - Dual voltage generators.  

Code of Federal Regulations, 2011 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) ELECTRICAL...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2011-10-01

78

Design, analysis, and testing of a precision guidance, navigation, and control system for a dual-spinning Cubesat  

E-print Network

The Microsized Microwave Atmospheric Satellite (MicroMAS) combines two traditional control approaches: a dual spinner and a three-axis gyrostat. Unlike typical dual spinners, the purpose of MicroMAS 's 2U bus and spinner ...

Wise, Evan Dale

2013-01-01

79

Decomposition and Customer Streams of Feedback Queueing Networks in Equilibrium.  

National Technical Information Service (NTIS)

P. J. Burke and E. Reich independently showed the output of a M/M/1 queue in equilibrium to be a Poisson process. Consequently, analysis of tandem exponential servers with a Poisson input stream can be reduced to consideration of a series of M/M/1 queues....

F. J. Beutler, B. Melamed

1975-01-01

80

Queueing systems subject to random server failures: an approximation  

E-print Network

In the traditional study of queueing theory, a typical ics. assumption is that the server is not subject to failures. This assumption, however, is not realistic for modeling many queueing systems in practice. Since the late 1950's, there has been...

Matis, Timothy

2012-06-07

81

Tagged Up\\/Down Sorter - A Hardware Priority Queue  

Microsoft Academic Search

We present a hardware oriented priority queue algorithm re- quiring n 2 comparators and swappers to maintain an n item queue. It supports two operations, insert and extract mini- mum (or alternatively, extract maximum), both of which op- erate in a single cycle. Thus, sorting time isO(n). Records with identical keys are always extracted in FIFO order of insertion. A

Simon W. Moore; Brian T. Graham

1995-01-01

82

The threat of punishment enforces peaceful cooperation and stabilizes queues  

E-print Network

The threat of punishment enforces peaceful cooperation and stabilizes queues in a coral-reef fish by subordinates as a form of peaceful cooperation whereby they avoid inflicting costs on dominants to promote the resolution of conflict over rank between group members. Keywords: social queue; eviction

Buston, Peter

83

HEAVYTRAFFIC EXTREMEVALUE LIMITS FOR QUEUES Peter W. Glynn  

E-print Network

HEAVY­TRAFFIC EXTREME­VALUE LIMITS FOR QUEUES by Peter W. Glynn Department of Operations Research­value distributions depend upon the queueing processes, and thus the model data, in a complicated way. Berger parameters. In particular, Berger and Whitt [6] developed and evaluated several heuristic approximations

Whitt, Ward

84

General Conference.(Part B) A FINITE BUFFER QUEUE  

E-print Network

the buffer sizelimits the amountof work that canbe stored in the queue. The arrival process is a Poisson or a Markov mod- ulated Poisson process. The service times (packet lengths) are iid with a general and the probability of packet loss. Key Words:Finite buffer queue, MMPP arrival process. 1. Introduction In this paper

Sharma, Vinod

85

Queues with waiting time dependent service , G.M. Koole  

E-print Network

; Deterministic threshold; Overflow; Level crossing. 1 Introduction In service systems, the tail probability (or]. Motivated by performance measures in terms of tail probabilities of waiting times, we consider queueing of the first customer in line. This model is related to the study of dams and queueing systems with workload

86

Improving multirobot, cooperative search via local target queues  

Microsoft Academic Search

Multirobot coordination techniques range from sharing state and intent information to explicit coordination strategies. The choice of cooperation strategy can affect task performance and resource utilization. This paper investigates the use of local search queues, rather than globally shared search queues. This work shows this change improves search in terms of interference and communications loads, two key factors in multirobot

Monica Anderson; Nikolaos Papanikolopoulos

2007-01-01

87

Queue response to input correlation functions: continuous spectral analysis  

Microsoft Academic Search

This paper, together with [1] and [2], opens a new window for the study of queueing performance in a richer, heterogeneous input environment. It offers a unique way to understand the effect of second- and higher-order input statistics on queues, and develops new concepts of traffic measurement, network control and resource allocation for high speed networks in the frequency domain.

San-qi Li; Chia-Lin Hwang

1993-01-01

88

BUS high current battery model  

Microsoft Academic Search

An empirical model for voltage and equivalent series resistance (ESR) has been developed for lead acid batteries used as a pulsed power source. During the design of the battery upgraded supply (BUS) for Eglin Air Force Base, the Center for Electromechanics at the University of Texas at Austin (CEM-UT) developed a model for the batteries to be used in this

J. P. Kajs; R. C. Zowarka

1993-01-01

89

HERMES travels by CAN bus  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

90

Sexual Harassment on the School Bus  

Microsoft Academic Search

Sexual harassment is commonplace in schools, particularly among adolescents. Although information on this topic is typically gathered from students and teachers, this study collected information from school bus drivers. Based on feedback from 58 school bus drivers, 39 (67%) reported observing students making sexual comments or jokes. Almost half of the bus drivers reported observing students “mooning” and\\/or “flashing.” Of

Melissa Allen; Ellie L. Young; Betty Y. Ashbaker; Emily Heaton; Marisa Parkinson

2003-01-01

91

School Bus Accidents and Driver Age.  

ERIC Educational Resources Information Center

The study examines the rates and types of school bus accidents according to the age of the school bus driver. Accident rates in North Carolina for the school year 1971-72 were analyzed using three sources of data: accident reports, driver and mileage data, and questionnaires administered to a sample of school bus drivers. Data were obtained on…

McMichael, Judith

92

Maximum Queue Length of a Fluid Model with a Gaussian Input  

E-print Network

queueing model, which is a queueing model with an input of a continuous Gaussian process, has received much attention. In this dissertation, a Gaussian queueing model is discussed and the maximum queue length over a time interval [0, t] is analyzed. Under...

Jin, Yasong

2007-12-11

93

PinBus Interface Design  

SciTech Connect

On behalf of the U.S. Department of Energy, PNNL has explored and expanded upon a simple control interface that might have merit for the inexpensive communication of smart grid operational objectives (demand response, for example) to small electric end-use devices and appliances. The approach relies on bi-directional communication via the electrical voltage states of from one to eight shared interconnection pins. The name PinBus has been suggested and adopted for the proposed interface protocol. The protocol is defined through the presentation of state diagrams and the pins’ functional definitions. Both simulations and laboratory demonstrations are being conducted to demonstrate the elegance and power of the suggested approach. PinBus supports a very high degree of interoperability across its interfaces, allowing innumerable pairings of devices and communication protocols and supporting the practice of practically any smart grid use case.

Hammerstrom, Donald J.; Adgerson, Jewel D.; Sastry, Chellury; Pratt, Richard M.; Pratt, Robert G.

2009-12-30

94

Updatable Queue Protocol Based On TCP For Virtual Reality Environment  

E-print Network

The variance in number and types of tasks required to be implemented within Distributed Virtual Environments (DVE) highlights the needs for communication protocols can achieve consistency. In addition, these applications have to handle an increasing number of participants and deal with the difficult problem of scalability. Moreover, the real-time requirements of these applications make the scalability problem more difficult to solve. In this paper, we have implemented Updatable Queue Abstraction protocol (UQA) on TCP (TCP-UQA) and compared it with original TCP, UDP, and Updatable Queue Abstraction based on UDP (UDP-UQA) protocols. Results showed that TCP-UQA was the best in queue management.

Al-Howaide, Ala'a Z; Salhieh, Ayad M

2011-01-01

95

On Poisson Approximations for Superposition Arrival Processes in Queues  

Microsoft Academic Search

We report on simulations of \\\\Sigma i<\\/sub>GIi<\\/sub>\\/M\\/1 queues; the arrival process is the superposition (sum) of up to 1024 i.i.d. renewal processes and there is a single exponential server. As one might anticipate, the simulation estimate of the expected number of customers in a \\\\Sigma i<\\/sub>GIi<\\/sub>\\/M\\/1 queueing system approaches the expected number in an M\\/M\\/1 queueing system as the number

S. L. Albin

1982-01-01

96

A new vehicle data bus architecture and IVIS evaluation platform for ITS modulus  

SciTech Connect

An increasing number of ITS-related after-market systems present a set of in-vehicle installation and use problems relatively unique in the history of automobile use. Many automobile manufacturers would like to offer these new state of the art devices to customers, but are hampered by the current design cycle of new cars. While auto manufacturers are indeed using multiplex buses (the automotive equivalent of a computer local area network), problems remain because manufacturers are not converging on a single bus standard. This paper presents a new dual-bus architecture to address these problems, with an In-Vehicle Information System (IVIS) research platform on which the principles embodied in the ITS Data Bus architecture can be evaluated. The dual-bus architecture has been embodied in a proposed SAE standard, with a ratification vote in December, 1996. The architecture and a reference model for the interfaces and protocols of the new bus are presented and described. The goals of the ITS Data Bus are to be inexpensive and easy to install, and to provide for safe and secure functioning. These high-level goals are embodied in the proposed standard. The IVIS Development Platform comprises a number of personal computers linked via ethernet LAN, with a high-end PC serving as the IVIS computer. In this LAN, actual devices can be inserted in place of the original PC which emulated them. This platform will serve as the development and test bed for an ITS Data Bus Conformity Test, the SAE standard for which has also been developed.

Spelt, P.F. [Oak Ridge National Lab., TN (United States); Kirson, A.M. [Motorola, Inc., Northbrook, IL (United States); Scott, S. [Jet Propulsion Lab., Washington, DC (United States)

1998-12-31

97

Longest-queue-first scheduling under SINR interference model  

E-print Network

We investigate the performance of longest-queue-first (LQF) scheduling (i.e., greedy maximal scheduling) for wireless networks under the SINR interference model. This interference model takes network geometry and the ...

Le, Long Bao

98

A Report on Stochastic Fairness Queueing (SFQ) Experiments  

NASA Technical Reports Server (NTRS)

SRI International (SRI) has developed an improved queueing algorithm, known as Stochastic Fairness Queueing (SFQ), for best-effort traffic (i.e., traffic that does not require any guaranteed service). SFQ is a probablistic variant of strict fair queueing where instead of a single queue being allocated per flow, a fixed number of queues are used and a hash function maps the IP source and destination to a particular queue. A seed to the hash function is also perturbed occasionally to help distribute the flows amongst different queues when more than one flow maps to the same queue during the lifetime of the flow. SFQ provides 'fair' access by trying to ensure that each flow from source to destination host obtains equal access to the available bandwidth. This report covers a series of experiments performed on DARTnet evaluating the behavior and performance of SFQ against a FIFO queueing discipline. These experiments were designed to show SFQ's advantages and performance, and include tests demonstrating: Fair utilization of available resources; Starvation prevention; Graceful degradation under overload conditions; and Resource usage. In general, the experiments do show that SFQ is better than FIFO queueing at allocating bandwidth equally among a set of flows. SFQ also prevents a stream from dominating the available bandwidth, which seems to be a tendency with FIFO queueing (i.e., if a flow demands more than its share of the available bandwidth, with FIFO queueing that stream receives a disproportionate amount when compared to flows demanding less than their share). Furthermore, SFQ seems to reward 'nice' users of the network by providing a lower variance in delay and more throughput when their resource demand is less than their available share. Both SFQ and FIFO queueing seem to degrade fairly well as the network becomes saturated and to recover well as the network becomes less congested. Not unexpectedly, FIFO queueing is a little more efficient than SFQ-the delays are less and the throughput slightly higher because SFQ requires more processing. However, the performance difference between the two queueing disciplines is relatively small. However, the experiments do point out some interesting behavior. FIFO queueing can behave better than SFQ with seed perturbation. We recommend further evaluation of the hash function and the seed perturbation technique. There are probably weaknesses in their current selection that cause this unexpected behavior. SFQ also seems to possess good scaling properties. To verify this, more experiments with a larger number of streams from more hosts need to be executed and examined, including the staggered introduction of streams. Staggering the streams may prove important, because graphs in the degradation experiment revealed some unexpected increases and decreases in throughput, which should be examined. This may again be due to the interaction of the hash function with the seed perturbation but it may also be related to some other unknown problem.

Denny, Barbara A.

1993-01-01

99

Sorting Using Networks of Stacks and Queues Stefan Felsner  

E-print Network

nodes are storage elements of type stack or queue. A railway switchyard could be an instance that the question is well motivated from a practical point of view, after all switchyards are cyclic in general

Felsner, Stefan

100

Integrating Queueing Theory and Scheduling for Dynamic Scheduling Problems  

E-print Network

Integrating Queueing Theory and Scheduling for Dynamic Scheduling Problems Daria Terekhov dterekho and conference papers (Terekhov, Tran, & Beck, 2010; Terekhov, Tran, Down, & Beck, 2012). The work in Section 4

Down, Doug

101

Optimal Routing in General Finite Multi-Server Queueing Networks  

PubMed Central

The design of general finite multi-server queueing networks is a challenging problem that arises in many real-life situations, including computer networks, manufacturing systems, and telecommunication networks. In this paper, we examine the optimal routing problem in arbitrary configured acyclic queueing networks. The performance of the finite queueing network is evaluated with a known approximate performance evaluation method and the optimization is done by means of a heuristics based on the Powell algorithm. The proposed methodology is then applied to determine the optimal routing probability vector that maximizes the throughput of the queueing network. We show numerical results for some networks to quantify the quality of the routing vector approximations obtained. PMID:25010660

van Woensel, Tom; Cruz, Frederico R. B.

2014-01-01

102

ON THE WORKLOAD PROCESS IN A FLUID QUEUE WITH  

E-print Network

between silence periods and active pe- riods+ At random epochs of times, the source becomes ready to send, the queue exceeds some threshold value K ~threshold discarding! @10#+ We have focused both on the discrete

103

Multiserver queueing in supervisory control of autonomous unmanned vehicles  

E-print Network

Multiserver queueing in supervisory control of autonomous unmanned vehicles Nathan D. Powel control of autonomous unmanned vehicles Nathan D. Powel Chair of the Supervisory Committee: Associate Professor Kristi Morgansen Aeronautics & Astronautics Widespread adoption of unmanned aerial vehicles has

Morgansen, Kristi

104

Behavior of queues at signalized intersections in heavy traffic  

NASA Technical Reports Server (NTRS)

This paper derives the asymptotic behavior of traffic queues at signalized intersections when the excess of departure capacity over arrivals approaches zero from above. The most interesting result is that the distribution of queue length approaches a negative exponential, with fewer restrictive assumptions than hitherto known. The main improvement results from more precise use of a combinatorial lemma of Spitzer, giving the maximum of the partial sums of a sequence of independent identically distributed random variables, plus some specific constructive probability calculations, many of them involving the Fourier transform. New results are presented on the probability that the queue be below a fixed bound and/or on the probability that the queue be empty. Applications to on-line estimators for real-time traffic control are suggested.

Posner, E. C.; Rodemich, E. R.

1976-01-01

105

Fairness and Scheduling in Single Server Queues Adam Wierman  

E-print Network

Fairness and Scheduling in Single Server Queues Adam Wierman Computing and Mathematical Sciences transactions. The same tradeoff has appeared across diverse computer system application areas, e.g., process

Wierman, Adam

106

Increasing available FIFO space to prevent messaging queue deadlocks in a DMA environment  

DOEpatents

Embodiments of the invention may be used to manage message queues in a parallel computing environment to prevent message queue deadlock. A direct memory access controller of a compute node may determine when a messaging queue is full. In response, the DMA may generate an interrupt. An interrupt handler may stop the DMA and swap all descriptors from the full messaging queue into a larger queue (or enlarge the original queue). The interrupt handler then restarts the DMA. Alternatively, the interrupt handler stops the DMA, allocates a memory block to hold queue data, and then moves descriptors from the full messaging queue into the allocated memory block. The interrupt handler then restarts the DMA. During a normal messaging advance cycle, a messaging manager attempts to inject the descriptors in the memory block into other messaging queues until the descriptors have all been processed.

Blocksome, Michael A. (Rochester, MN); Chen, Dong (Croton On Hudson, NY); Gooding, Thomas (Rochester, MN); Heidelberger, Philip (Cortlandt Manor, NY); Parker, Jeff (Rochester, MN)

2012-02-07

107

An analysis of queueing systems with multi-task servers  

Microsoft Academic Search

We study a Markovian queueing system with multi-task servers. Each server can perform two types of job-serving the queue as primary jobs and taking vacations as secondary jobs. In such a system with c>1 servers, if at a service completion instant the server finds no customer waiting in line and the number of servers already on vacations is less than

Zhe George Zhang; Naishuo Tian

2004-01-01

108

Predicting Queue Times on Space-Sharing Parallel Computers  

Microsoft Academic Search

We present statistical techniques for predicting the queue times experienced by jobs submitted to a space-sharing par- allel machine with first-come-first-served (FCFS) schedul- ing. We apply these techniques to trace data from the Intel Paragon at the San Diego Supercomputer Center and the IBM SP2 at the Cornell Theory Center. We show that it is possible to predict queue times

Allen B. Downey

1997-01-01

109

Ride comfort optimization of a city bus  

Microsoft Academic Search

.   Ride comfort optimization of a city bus is considered in this article, using stiffness and related damping of the power unit\\u000a mounts as design variables. The response of the bus, due to road irregularities, is calculated in the time domain by using\\u000a a finite element (FE) model describing the complete vehicle. The body of the bus is condensed, using

P. Eriksson; O. Friberg

2000-01-01

110

Evaluation of concurrent priority queue algorithms. Technical report  

SciTech Connect

The priority queue is a fundamental data structure that is used in a large variety of parallel algorithms, such as multiprocessor scheduling and parallel best-first search of state-space graphs. This thesis addresses the design and experimental evaluation of two novel concurrent priority queues: a parallel Fibonacci heap and a concurrent priority pool, and compares them with the concurrent binary heap. The parallel Fibonacci heap is based on the sequential Fibonacci heap, which is theoretically the most efficient data structure for sequential priority queues. This scheme not only preserves the efficient operation time bounds of its sequential counterpart, but also has very low contention by distributing locks over the entire data structure. The experimental results show its linearly scalable throughput and speedup up to as many processors as tested (currently 18). A concurrent access scheme for a doubly linked list is described as part of the implementation of the parallel Fibonacci heap. The concurrent priority pool is based on the concurrent B-tree and the concurrent pool. The concurrent priority pool has the highest throughput among the priority queues studied. Like the parallel Fibonacci heap, the concurrent priority pool scales linearly up to as many processors as tested. The priority queues are evaluated in terms of throughput and speedup. Some applications of concurrent priority queues such as the vertex cover problem and the single source shortest path problem are tested.

Huang, Q.

1991-02-01

111

Implementing GIS in Bus Identification and Monitoring System  

Microsoft Academic Search

GIS is a system that analyses and displays geographic information. This paper focuses on the GIS application for Bus Identification and Monitoring System. GIS is used to map out the bus location and movement in the system. The results show that the bus operation in terms of time schedule, driver's and bus' identification, and bus' location can be monitored and

Aishah Mahani Mustapha; MA Hannan; Aini Hussain; Hassan Basri

2011-01-01

112

School Bus Driver Instructional Program. Course Guide.  

ERIC Educational Resources Information Center

A standardized and comprehensive school bus driver instructional program has been developed under contract with the Federal Government. The course has been organized to provide in one package a program for developing the minimum skills and knowledge needed by the school bus driver, as well as those supplemental skills and knowledge which the…

Department of Transportation, Washington, DC. National Highway Safety Bureau.

113

Expert Offers School Bus Safety Tips  

MedlinePLUS

... on how to avoid accidents: To keep them out of the blind spot, encourage kids to stay 10 feet away from the front or back of the school bus. Get children to the school bus stop at least 5 minutes early so they won't put themselves at risk ...

114

Who's Driving This Bus Anyway? Empowering Drivers.  

ERIC Educational Resources Information Center

In 1977, a school transportation director developed a policy giving school bus drivers authority to discipline unruly student behavior via a system of graduated warnings and suspension of riding privileges. Most parents have been supportive and expect their kids to behave on the bus. In the interest of safety, school administrators should support…

Allen, J. D.

1997-01-01

115

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

DOEpatents

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.

Atac, Robert (Aurora, IL); Fischler, Mark S. (Warrenville, IL); Husby, Donald E. (DeKalb, IL)

1991-01-01

116

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

DOEpatents

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.

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

1991-01-15

117

User equilibria for a parallel queueing system with state dependent routing  

Microsoft Academic Search

Consider a system of two queues in parallel, one of which is a ?|M|1 single-server infinite capacity queue, and the other a ?|G\\u000a (N)|? batch service queue. A stream of general arrivals choose which queue to join, after observing the current state of the\\u000a system, and so as to minimize their own expected delay. We show that a unique user equilibrium

Heti Afimeimounga; Wiremu Solomon; Ilze Ziedins

2010-01-01

118

Rate-based versus queue-based models of congestion control  

Microsoft Academic Search

Mathematical models of congestion control capture the congestion indication mechanism at the router in two different ways: rate-based models, where the queue-length at the router does not explicitly appear in the model, and queue-based models, where the queue length at the router is explicitly a part of the model. Even though most congestion indication mechanisms use the queue length to

Supratim Deb; R. Srikant

2004-01-01

119

Rate-based versus queue-based models of congestion control  

Microsoft Academic Search

Mathematical models of congestion control capture the congestion indication mechanism at the router in two different ways: Rate-based models, where the queue-length at the router does not explicitly appear in the model, and queue-based models, where the queue length at the router is explicitly a part of the model. Even though most congestion indication mechanisms use the queue length to

Supratim Deb; R. Srikant

2006-01-01

120

Analog bus driver and multiplexer  

NASA Technical Reports Server (NTRS)

For a source-follower signal chain, the ohmic drop in the selection switch causes unacceptable voltage offset, non-linearity, and reduced small signal gain. For an op amp signal chain, the required bias current and the output noise rises rapidly with increasing the array format due to a rapid increase in the effective capacitance caused by the Miller effect boosting up the contribution of the bus capacitance. A new switched source-follower signal chain circuit overcomes limitations of existing op-amp based or source follower based circuits used in column multiplexers and data readout. This will improve performance of CMOS imagers, and focal plane read-out integrated circuits for detectors of infrared or ultraviolet light.

Pain, Bedabrata (Inventor); Hancock, Bruce (Inventor); Cunningham, Thomas J. (Inventor)

2012-01-01

121

Zero-Buffer Queueing Networks Andriansyah, van Woensel, Cruz, & Duczmal Performance Optimization of  

E-print Network

Zero-Buffer Queueing Networks Andriansyah, van Woensel, Cruz, & Duczmal Performance Optimization of Open Zero-Buffer Multi-Server Queueing Networks R. Andriansyah T. Van Woensel F. R. B. Cruz§ L. Duczmal Abstract -- Open zero-buffer multi-server general queue- ing networks occur throughout a number of physical

Cruz, Frederico

122

A genetic algorithm for the design of a fuzzy controller for active queue management  

Microsoft Academic Search

Active queue management (AQM) policies are those policies of router queue management that allow for the detection of network congestion, the notification of such occurrences to the hosts on the network borders, and the adoption of a suitable control policy. This paper proposes the adoption of a fuzzy proportional integral (FPI) controller as an active queue manager for Internet routers.

Giuseppe Di Fatta; F. Hoffmann; Giuseppe Lo Re; Alfonso Urso

2003-01-01

123

Using Queueing Network Models to Set Lot-sizing Policies for Printed Circuit Board Assembly Operations  

E-print Network

1 Using Queueing Network Models to Set Lot-sizing Policies for Printed Circuit Board Assembly because more setup time is incurred. In this paper, we propose the use of queueing network models to determine the best lot-sizing policy that minimizes the WIP. The queueing network model is validated

Dessouky, Maged

124

A Dynamical Queue Approach to Intelligent Task Management for Human Operators  

Microsoft Academic Search

Formal methods for task management for human operators are gathering increasing attention to improve efficiency of human-in-the-loop systems. In this paper, we consider a novel dynamical queue approach to intelligent task management for human operators. We consider a model of a dynamical queue, where the service time depends on the server utilization history. The proposed queueing model is motivated by,

Ketan Savla; Emilio Frazzoli

2012-01-01

125

Simple queueing model applied to the city of Portland  

SciTech Connect

The authors present a simple traffic micro-simulation model that models the effects of capacity cut-off, i.e. the effect of queue built-up when demand is exceeding capacity, and queue spillback, i.e. the effect that queues can spill back across intersections when a congested link is filled up. They derive the model`s fundamental diagrams and explain it. The simulation is used to simulate traffic on the emme/2 network of the Portland (Oregon) metropolitan region (20,000 links). Demand is generated by a simplified home-to-work assignment which generates about half a million trips for the AM peak. Route assignment is done by iterative feedback between micro-simulation and router. Relaxation of the route assignment for the above problem can be achieved within about half a day of computing time on a desktop workstation.

Simon, P.M.; Nagel, K. [Los Alamos National Lab., NM (United States)]|[Santa Fe Inst., NM (United States)

1998-07-31

126

Parallel discrete-event simulation of FCFS stochastic queueing networks  

NASA Technical Reports Server (NTRS)

Physical systems are inherently parallel. Intuition suggests that simulations of these systems may be amenable to parallel execution. The parallel execution of a discrete-event simulation requires careful synchronization of processes in order to ensure the execution's correctness; this synchronization can degrade performance. Largely negative results were recently reported in a study which used a well-known synchronization method on queueing network simulations. Discussed here is a synchronization method (appointments), which has proven itself to be effective on simulations of FCFS queueing networks. The key concept behind appointments is the provision of lookahead. Lookahead is a prediction on a processor's future behavior, based on an analysis of the processor's simulation state. It is shown how lookahead can be computed for FCFS queueing network simulations, give performance data that demonstrates the method's effectiveness under moderate to heavy loads, and discuss performance tradeoffs between the quality of lookahead, and the cost of computing lookahead.

Nicol, David M.

1988-01-01

127

Ultralight Stainless Steel Urban Bus Concept  

SciTech Connect

While stainless steel buses are certainly not new, this study reveals opportunities for substantial improvements in structural performance.The objective of this project was to investigate the mass saving potential of ultra-high strength stainless steel as applied to the structure of a full size urban transit bus.The resulting design for a low floor,hybrid bus has an empty weight less than half that of a conventional transit bus.The reduced curb weight allows for a greater payload,without exceeding legal axle limits. A combination of finite element modeling and dynamic testing of scale models was used to predict structural performance.

J. Bruce Emmons; Leonard J. Blessing

2001-05-14

128

Entropy estimation for M/M/1 queueing systems  

NASA Astrophysics Data System (ADS)

The aim of this paper is to estimate the entropy of Markovian queueing systems. The marginal entropy and entropy rate of a stochastic process are well-known to measure its uncertainty. When only observations of the process are available, the need to estimate themarises. Regnault [5, 6] provide estimators with good asymptotic properties of the entropy of continuous-time ergodic Markov processes. We specialize these results in the context of birth-death processes used in continuous-time M/M/1 queueing systems. Links with maximum entropy arguments are used to characterize the asymptotic behavior of the estimators.

Regnault, Philippe

2012-05-01

129

Computerized Bus Routing in San Francisco.  

ERIC Educational Resources Information Center

A computerized routing and scheduling system for the San Francisco Public Schools includes the batch processing of bus route assignments and schedules for all schools and the online terminal processing of daily changes. (Author/MLF)

Caswell, Peter J.; Jungherr, J. Anton

1979-01-01

130

16 Load Data Cleansing and Bus Load  

E-print Network

375 16 Load Data Cleansing and Bus Load Coincidence Factors* Wenyuan Li, Ke Wang, and Wijarn .................................................................................................. 375 16.2 Load Curve Data Cleansing..................................................................................377 16.2.2 Method for Cleansing Outliers .........................................................378

Wang, Ke

131

Finding an Individual Optimal Threshold of Queue Length in Hybrid Overlay/Underlay Spectrum Access in Cognitive Radio Networks  

NASA Astrophysics Data System (ADS)

In this paper, a hybrid overlay/underlay cognitive radio system is modeled as an M/M/1 queue where the rate of arrival and the service capacity are subject to Poisson alternations. Each packet as a customer arriving at the queue makes a decision to join the queue or not. Upon arrival, the individual decision of each packet is optimized based on his observation about the queue length and the state of system. It is shown that the individually optimal strategy for joining the queue is characterized by a threshold of queue length. Thus, the individual optimal threshold of queue length is analyzed in detail in this work.

Do, Cuong T.; Tran, Nguyen H.; Hong, Choong Seon; Lee, Sungwon

132

TMS communications software. Volume 2: Bus interface unit  

NASA Technical Reports Server (NTRS)

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.

Gregor, P. J.

1979-01-01

133

A Self-Clocked Fair Queueing Scheme for Broadband Applications  

Microsoft Academic Search

An eficient fair queueing scheme which is feasi- ble for broadband implementation is proposed and its performance is analyzed. We define fairness in a self- contained manner, eliminating the need for the hypo- thetical fluid-flow reference system used in the present state of art and thereby removing the associated com- putational complexity. The scheme is based on the adoption of

S. Jamaloddin Golestani

1994-01-01

134

Recommendations on Queue Management and Congestion Avoidance in the Internet  

Microsoft Academic Search

This memo presents two recommendations to the Internet community concerning measures to improve and preserve Internet performance. It presents a strong recommendation for testing, standardization, and widespread deployment of active queue management in routers, to improve the performance of today's Internet. It also urges a concerted effort of research, measurement, and ultimate deployment of router mechanisms to protect the Internet

B. Braden; D. Clark; J. Crowcroft; UCL B. Davie; S. Deering; D. Estrin; V. Jacobson; G. Minshall; C. Partridge; BBN L. Peterson; K. Ramakrishnan; S. Shenker; LCS L. Zhang

1998-01-01

135

Recommendations on Queue Management and Congestion Avoidance in the Internet  

Microsoft Academic Search

This memo presents two recommendations to the Internet community concerning measuresto improve and preserve Internet performance. It presents a strong recommendationfor testing, standardization, and widespread deployment of active queue managementin routers, to improve the performance of today's Internet. It also urges aconcerted effort of research, measurement, and ultimate deployment of router mechanismsto protect the Internet from flows that are not

Bob Braden

1997-01-01

136

Lyapunov-based Fuzzy Queue Scheduling for Internet Routers  

Microsoft Academic Search

Quality of Service (QoS) in the Internet depends on queuing and sophisticated scheduling in routers. In this paper, we address the issue of managing traffic flows with different priorities. In our reference model, incoming packets are first classified based on their priority, placed into different queues with different capacities, and then multiplexed onto one router link. The fuzzy nature of

Hyun Cheol Cho; M. Sami Fadali; Jin Woo Lee; Young Jin Lee; Kwon Soon Lee

2007-01-01

137

Dynamic Queue Scheduling Using Fuzzy Systems for Internet Routers  

Microsoft Academic Search

Quality of service (QoS) in the Internet depends on queuing and sophisticated scheduling in routers. In this paper, we address the issue of managing traffic flows with different priorities. In our reference model, incoming packets are first classified based on their priority, placed into different queues with different capacities, and then multiplexed onto one router link. The fuzzy nature of

Hyun C. Cho; M. Sami Fadali; Hyunjeong Lee

2005-01-01

138

Job queues and the union status of workers  

Microsoft Academic Search

This paper develops a model of the determination of the union status of workers that allows for the possibility of queuing for union jobs. The empirical results derived, using a sample from the University of Michigan Panel Study of Income Dynamics, are supportive of the queuing hypothesis. The no-queue model can be rejected using a likelihood-ratio test. This suggests that

John M. Abowd; Henry S. Farber

1982-01-01

139

Scheduling in a Queueing System with Asynchronously Varying Service Rates  

Microsoft Academic Search

Abstract: We consider the following queueing system which arises as a model of a wirelesslink shared by multiple users. There is anite number N of input ows served by aserver. The system operates in discrete time t = 0; 1; 2; : : : . Each input ow can bedescribed as an irreducible countable Markov chain; waiting customers of each

M. Andrews; K. Kumaran; K. Ramanan; A. L. Stolyar; R. Vijayakumar; P. Whiting

2000-01-01

140

Job Queues, Certification Status, and the Education Labor Market  

ERIC Educational Resources Information Center

This research explores the interaction between training programs and certification status in one education labor market to examine the micro-level interactions that shape the recruitment process. Using job queue theory, it is found that the information available to novice teachers operates to stratify and shape their worksite choices in addition…

Evans, Lorraine

2011-01-01

141

Flow Management in Packet Networks Through Interacting Queues  

E-print Network

Thomas Meyer and Christian Tschudin Technical Report CS-2011-001 University of Basel January 31st, 2011 Abstract Classical queueing disciplines are work conserving: From the allocated chan- nel's perspective engineering wise, the resulting network dynamics is difficult to handle. In this report, we show

Vetter, Thomas

142

Worst-Case Efficiency Analysis of Queueing Disciplines  

E-print Network

Worst-Case Efficiency Analysis of Queueing Disciplines Damon Mosk-Aoyama and Tim Roughgarden1 dictate the allocation x = (x1, . . . , xn) can easily choose the allocation that maximizes the welfare W natural way to proceed is equilibrium analysis, where we model each user as maximizing its own payoff

Roughgarden, Tim

143

GPS Queues with Heterogeneous Traffic Classes Sem Borst,,  

E-print Network

GPS Queues with Heterogeneous Traffic Classes Sem Borst,, , Michel Mandjes, , Miranda van Uitert traffic classes are served in accordance with the Gen- eralized Processor Sharing (GPS) discipline. GPS of the light-tailed class for the situation where its GPS weight is larger than its traffic intensity. The GPS

Boucherie, Richard J.

144

Permuting machines and priority queues R. E. L. Aldred  

E-print Network

Permuting machines and priority queues R. E. L. Aldred M. D. Atkinson H. P. van Ditmarsch C. C. Handley D. A. Holton D. J. McCaughan March 31, 2005 Abstract Machines whose sole function is to re-order their input data are consid- ered. Every such machine defines a set of allowable input-output pairs

Atkinson, Mike

145

A fair queueing architecture for ATM switches with input buffers  

Microsoft Academic Search

The available bit rate (ABR) and unspecified bit rate (UBR) are reservationless service categories at the ATM layer. ATM switches are required to have large cell buffers to provide such services. A new queueing architecture named Kago for the large input buffer switch is proposed. Kago provides per-VC fair scheduling among the multiple input buffers. The mechanism is divided among

Yosliiniitsu Shimojo; Toshiba Corp

1996-01-01

146

Quasi-Stationary Approximation for PPBP Queues -Mathematica  

E-print Network

Quasi-Stationary Approximation for PPBP Queues - Mathematica Source Code Ron Addie, University of Southern Queensland, September 2008 This notebook contains all the mathematica procedures, including plots-1113 . If you wish to have access to the mathematica notebook from which this document was generated, please

Zukerman, Moshe

147

Queueing up for enzymatic processing: correlated signaling through coupled degradation  

E-print Network

the observed network connections is critical for the further development of systems and synthetic biology. Here queueing using a synthetic biology application, in which two independent synthetic networks demonstrate 2011; doi:10.1038/msb.2011.94 Subject Categories: metabolic & regulatory networks; synthetic biology

148

An optimization of bus interconnects pitch for low-power and reliable bus encoding scheme  

Microsoft Academic Search

Energy consumption is one of the most critical constraints in the current VLSI system designs. In addition, fault tolerance of VLSI systems is also one of the most important requirements in the current shrunk VLSI technologies. This paper presents low power and fault tolerant bus encoding methods considering coupling effects of bus interconnects. Experiments using SPEC2000 benchmark programs show that

Satoshi Komatsu; Masahiro Fujita

2006-01-01

149

Empirical findings of Bus Bunching Distributions and Attributes Using Archived AVL/APC Bus Data  

E-print Network

performance. This study is motivated by the low performance of a route operated by Portland Tri problems, it may be possible to implement corrective measures and new strategies to improve bus operations causes include improper schedule design, stop spacing, and bus operator behaviors; external causes

Bertini, Robert L.

150

Effects of the Bus Regulatory Reform Act of 1982 on the Texas intercity bus industry  

E-print Network

. The passage of the Bus Regulatory Reform Act of 1982 was an effort to decrease operating costs and increase ridership by allowing bus companies to discontinue unprofitable routes, have freedom over the setting of fares, and enter into new, competitive markets...

Kuenzer, Karen Elizabeth

2012-06-07

151

Sexual Harassment on the School Bus: Supporting and Preparing Bus Drivers to Respond Appropriately  

ERIC Educational Resources Information Center

Sexual harassment is commonplace in schools, particularly among adolescents. Although information on this topic is typically gathered from students and teachers, this study collected information from school bus drivers. Based on feedback from 58 school bus drivers, 39 (67%) reported observing students making sexual comments or jokes. Almost half…

Allen, Melissa; Young, Ellie L.; Ashbaker, Betty Y.; Heaton, Emily; Parkinson, Marisa

2003-01-01

152

School Bus and School Pupil Activity Bus Inspection and Maintenance Guide.  

ERIC Educational Resources Information Center

This publication deals with suggested maintenance standards that apply to vehicles used for pupil transportation in California and covers all the safety-related systems that are common to most buses. The guide has been prepared to help all school bus and school pupil activity bus operators set up an inspection and preventive maintenance program…

Sowash, Fred W.

153

Bus dispatching at timed transfer transit stations using bus tracking technology  

Microsoft Academic Search

A timed transfer terminal synchronizes the arrival of incoming vehicles with the departure of outgoing vehicles so as to minimize transfer delays. Most bus timed transfer terminals follow fixed schedules, and do not utilize intelligent transportation systems for vehicle tracking and control. This paper reviews technologies that enable real-time control of timed transfer. We evaluate the benefits of tracking bus

Maged Dessouky; Randolph Hall; Ali Nowroozi; Karen Mourikas

1999-01-01

154

Running the model in production mode: using the queue. High performance computing (HPC) systems use a queue system to make  

E-print Network

Running the model in production mode: using the queue. High performance computing (HPC) systems use. I've worked on three HPC systems to date, and each is quite similar in this regard, although. But processors are connected together in clusters, or nodes, that are more tightly bound together. On NYU's HPC

Gerber, Edwin

155

Fuel Cell Bus Takes a Starring Role in the BurbankBus Fleet (Fact Sheet)  

SciTech Connect

This fact sheet reports on the City of Burbank, California's fuel cell bus demonstration project and the U.S. Department of Energy's (DOE) involvement. Included are specifications for the fuel cell bus and information about its operation. BurbankBus, the city's mass transit entity, received a grant from the California Air Resources Board to fund its zero-emission bus demonstration and is collaborating with DOE's Fuel Cell Technologies Program to evaluate the bus performance. DOE's National Renewable Energy Laboratory will collect and analyze performance and operations data for at least one year. Researchers will use the data to better understand the technology and determine future development work. In addition, demonstration information will help fleets make informed purchase decisions.

Not Available

2010-05-01

156

[Tuberculosis microepidemic in a commuter bus].  

PubMed

A tuberculosis microepidemic in a commuter bus was reported. Index patient was a 22-year-old woman who was an employee of an electronic company. An abnormal shadow was found on her chest roentgenogram during an annual medical check-up in June, 1996. As her sputum smear was Gaffky 6, she was admitted to our hospital for medication. Extraordinary examinations including PPD skin test and chest X-ray were carried out on 49 employees of the company in October, 1996. As the result of these examinations, the distribution of maximum diameters of erythema in PPD skin test showed bimodal distribution, and tuberculosis was discovered in two patients by Chest X-ray examination. Moreover, preventive administration of Isonicotinic acid hydrazide (INH) was indicated for 3 employees based on very strong skin reaction to PPD. These five employees were working separately from the index patient and had little contact with the patient in the work places, but using a same commuter bus. Therefore, we strongly suspect that they were infected from the index patient not in the work place but in the commuter bus. The air-conditioning of the bus used a closed recirculation system, hence insufficient ventilation in the bus contributed to the spread of tuberculosis infection. PMID:10423962

Yagi, T; Sasaki, Y; Yamagishi, F; Mizutani, F; Wada, A; Kuroda, F

1999-06-01

157

VICbus: A standard inter-crate bus  

NASA Astrophysics Data System (ADS)

VICbus is a standard inter-crate cable bus being developed by a working group of the ISO/IEC. Derived from an initiative of the VMEbus Working Group of ESONE, VICbus aims to provide users of multi-crate VMEbus and other backplane bus systems with a standard inter-crate connection. Multi-drop operation is provided for up to 31 devices on a cable of maximum 100 metres in length. Two data transfer protocols are specified, compelled (asynchronous) transfers for transparent interconnection of backplane bus systems (VMEbus in the first instance), and high-speed, non-compelled (synchronous) transfers between VICbus interfaces. A limited interrupt mechanism is specified, as well as simple, but efficient arbitration technique. Conventional technology is employed: copper cables, existing transcievers, and differential signal transmission, together with proven low-level protocols. Data transfer rates in excess of 30 Mbyte/s will be possible on a cable length of 30 metres.

Parkman, Christopher F.

1990-08-01

158

Generalized priority-queue network dynamics: impact of team and hierarchy.  

PubMed

We study the effect of team and hierarchy on the waiting-time dynamics of priority-queue networks. To this end, we introduce generalized priority-queue network models incorporating interaction rules based on team-execution and hierarchy in decision making, respectively. It is numerically found that the waiting-time distribution exhibits a power law for long waiting times in both cases, yet with different exponents depending on the team size and the position of queue nodes in the hierarchy, respectively. The observed power-law behaviors have in many cases a corresponding single or pairwise-interacting queue dynamics, suggesting that the pairwise interaction may constitute a major dynamic consequence in the priority-queue networks. It is also found that the reciprocity of influence is a relevant factor for the priority-queue network dynamics. PMID:20866480

Cho, Won-kuk; Min, Byungjoon; Goh, K-I; Kim, I-M

2010-06-01

159

Generalized priority-queue network dynamics: Impact of team and hierarchy  

NASA Astrophysics Data System (ADS)

We study the effect of team and hierarchy on the waiting-time dynamics of priority-queue networks. To this end, we introduce generalized priority-queue network models incorporating interaction rules based on team-execution and hierarchy in decision making, respectively. It is numerically found that the waiting-time distribution exhibits a power law for long waiting times in both cases, yet with different exponents depending on the team size and the position of queue nodes in the hierarchy, respectively. The observed power-law behaviors have in many cases a corresponding single or pairwise-interacting queue dynamics, suggesting that the pairwise interaction may constitute a major dynamic consequence in the priority-queue networks. It is also found that the reciprocity of influence is a relevant factor for the priority-queue network dynamics.

Cho, Won-Kuk; Min, Byungjoon; Goh, K.-I.; Kim, I.-M.

2010-06-01

160

Conservative parallel simulation of priority class queueing networks  

NASA Technical Reports Server (NTRS)

A conservative synchronization protocol is described for the parallel simulation of queueing networks having C job priority classes, where a job's class is fixed. This problem has long vexed designers of conservative synchronization protocols because of its seemingly poor ability to compute lookahead: the time of the next departure. For, a job in service having low priority can be preempted at any time by an arrival having higher priority and an arbitrarily small service time. The solution is to skew the event generation activity so that the events for higher priority jobs are generated farther ahead in simulated time than lower priority jobs. Thus, when a lower priority job enters service for the first time, all the higher priority jobs that may preempt it are already known and the job's departure time can be exactly predicted. Finally, the protocol was analyzed and it was demonstrated that good performance can be expected on the simulation of large queueing networks.

Nicol, David M.

1990-01-01

161

The Effect of Queueing Strategy on Network Traffic  

NASA Astrophysics Data System (ADS)

In recent years, the transportation system has been faced by increasing challenge in congestion and inefficiency, and research in traffic network has become a significant area of interest. In this paper, we introduce a dynamic-information-based (DIB) queueing strategy into network traffic model under the efficient routing strategy. DIB makes a packet with higher priority to be delivered if there are less packets travelling along its path from the current node to the destination. It is found that, compared with the traditional first-in-first-out (FIFO) queueing strategy, DIB can effectively balance the traffic load of the system via delaying packets to be delivered to congested nodes. Although the network capacity has no obvious changes, some other indexes which reflect transportation efficiency are efficiently improved in the congestion state. Besides, extensive simulation results and discussions are provided to explain the phenomena. The results may provide novel insights for research on traffic systems.

Zhang, Xue-Jun; Guan, Xiang-Min; Sun, Deng-Feng; Tang, Shao-Ting

2013-10-01

162

Resource Selection Using Execution and Queue Wait Time Predictions  

NASA Technical Reports Server (NTRS)

Computational grids provide users with many possible places to execute their applications. We wish to help users select where to run their applications by providing predictions of the execution times of applications on space shared parallel computers and predictions of when scheduling systems for such parallel computers will start applications. Our predictions are based on instance based learning techniques and simulations of scheduling algorithms. We find that our execution time prediction techniques have an average error of 37 percent of the execution times for trace data recorded from SGI Origins at NASA Ames Research Center and that this error is 67 percent lower than the error of user estimates. We also find that the error when predicting how long applications will wait in scheduling queues is 95 percent of mean queue wait times when using our execution time predictions and this is 57 percent lower than if we use user execution time estimates.

Warren, Smith; Wong, Parkson; Biegel, Bryan A. (Technical Monitor)

2002-01-01

163

On Queueing Network Models of Flexible Manufacturing Systems  

Microsoft Academic Search

This paper outlines the state-of-the-art in studying flexible manufacturing systems (FMSs) using analytical queueing network models. These include Jackson networks, reversible networks and approximate models of non-product-form networks. The focus is on identifying the major features of the models as they relate to the operational characteristics of FMSs. Prescriptive models concerning the optimal design and\\/or operational control of FMS networks

John A. Buzacott; David D. Yao

1986-01-01

164

Cooperative dynamics of loyal customers in queueing networks  

Microsoft Academic Search

We consider queueing networks (QN’s) with feedback loops roamed by “intelligent” agents, able to select their routing on the\\u000a basis of their measured waiting times at the QN nodes. This is an idealized model to discuss the dynamics of customers who\\u000a stay loyal to a service supplier, provided their service time remains below a critical threshold. For these QN’s, we

Olivier Gallay; Max-Olivier Hongler

2008-01-01

165

GENERAL: The queueing model for quantum key distribution network  

NASA Astrophysics Data System (ADS)

This paper develops a QKD (quantum key distribution)-based queueing model to investigate the data delay on QKD link and network, especially that based on trusted relays. It shows the mean packet delay performance of the QKD system. Furthermore, it proposes a key buffering policy which could effectively improve the delay performance in practice. The results will be helpful for quality of service in practical QKD systems.

Wen, Hao; Han, Zheng-Fu; Guo, Guang-Can; Hong, Pei-Lin

2009-01-01

166

Stacks, Queues and Tracks: Layouts of Graph Subdivisions  

Microsoft Academic Search

Abstract A k-stack layout (respectively, k-queue layout) of a graph consists of a total order of the vertices, and a partition of the edges into k sets of non-crossing (non-nested) edges with respect to the vertex ordering. A k-track layout of a graph consists of a vertex k-colouring, and a total order of each vertex colour class, such that between

Vida Dujmovic; David R. Wood

2005-01-01

167

Communication Subsystem Synthesis and Analysis Tool using Bus Architecture Generation and  

E-print Network

that various constraints, like bus length, topology complexity, potential for communication conflicts over time function models bus length, bus topology complexity, potential for communication conflicts over timeCommunication Subsystem Synthesis and Analysis Tool using Bus Architecture Generation

Doboli, Simona

168

32 CFR 935.138 - Motor bus operation.  

... 6 2014-07-01 2014-07-01 false Motor bus operation. 935.138 Section 935.138...TERRITORIAL AND INSULAR REGULATIONS WAKE ISLAND CODE Motor Vehicle Code § 935.138 Motor bus operation. Each person operating a...

2014-07-01

169

Queueing models for token and slotted ring networks. Thesis  

NASA Technical Reports Server (NTRS)

Currently the end-to-end delay characteristics of very high speed local area networks are not well understood. The transmission speed of computer networks is increasing, and local area networks especially are finding increasing use in real time systems. Ring networks operation is generally well understood for both token rings and slotted rings. There is, however, a severe lack of queueing models for high layer operation. There are several factors which contribute to the processing delay of a packet, as opposed to the transmission delay, e.g., packet priority, its length, the user load, the processor load, the use of priority preemption, the use of preemption at packet reception, the number of processors, the number of protocol processing layers, the speed of each processor, and queue length limitations. Currently existing medium access queueing models are extended by adding modeling techniques which will handle exhaustive limited service both with and without priority traffic, and modeling capabilities are extended into the upper layers of the OSI model. Some of the model are parameterized solution methods, since it is shown that certain models do not exist as parameterized solutions, but rather as solution methods.

Peden, Jeffery H.

1990-01-01

170

Apparatus and method for managing digital resources by passing digital resource tokens between queues  

DOEpatents

A method of managing digital resources of a digital system includes the step of reserving token values for certain digital resources in the digital system. A selected token value in a free-buffer-queue is then matched to an incoming digital resource request. The selected token value is then moved to a valid-request-queue. The selected token is subsequently removed from the valid-request-queue to allow a digital agent in the digital system to process the incoming digital resource request associated with the selected token. Thereafter, the selected token is returned to the free-buffer-queue. 6 figs.

Crawford, H.J.; Lindenstruth, V.

1999-06-29

171

Apparatus and method for managing digital resources by passing digital resource tokens between queues  

DOEpatents

A method of managing digital resources of a digital system includes the step of reserving token values for certain digital resources in the digital system. A selected token value in a free-buffer-queue is then matched to an incoming digital resource request. The selected token value is then moved to a valid-request-queue. The selected token is subsequently removed from the valid-request-queue to allow a digital agent in the digital system to process the incoming digital resource request associated with the selected token. Thereafter, the selected token is returned to the free-buffer-queue.

Crawford, Henry J. (Berkeley, CA); Lindenstruth, Volker (El Cerrito, CA)

1999-01-01

172

Analysis of a diesel-electric hybrid urban bus system  

NASA Astrophysics Data System (ADS)

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.

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

173

Analysis of a diesel-electric hybrid urban bus system  

SciTech Connect

A hybrid bus powered by a diesel engine and a battery pack has been analyzed over an idealized bus-driving cycle in Chicago. Three hybrid configurations, two parallel and one series, have been 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.

Marr, W.W.; Sekar, R.R. [Argonne National Lab., IL (United States); Ahlheim, M.C. [Regional Transportation Authority, Chicago, IL (United States)

1993-08-01

174

Bus Maintenance is a Sound Investment.  

ERIC Educational Resources Information Center

Preventive school bus maintenance to reduce long-term costs should include daily visual inspections by drivers, frequent checks by mechanics, and comprehensive inspections every 5,000 miles. Mechanics recommend checking tail lights, batteries, brakes, lug nuts, leaf springs, tail pipes, and exhaust pipe hangers. (RW)

American School Board Journal, 1981

1981-01-01

175

Repeater For A Digital-Communication Bus  

NASA Technical Reports Server (NTRS)

Digital repeater circuit designed to extend range of communication on MIL-STD-1553 bus beyond original maximum allowable length of 300 ft. Circuit provides two-way communication, one way at time, and conforms to specifications of MIL-STD-1553. Crosstalk and instability eliminated.

Torres-Guzman, Esteban; Olson, Stephen; Heaps, Tim

1993-01-01

176

A Survey of Computerized School Bus Routing.  

ERIC Educational Resources Information Center

A review of significant activities in the area of computerized school bus routing is conducted. The various factors which contribute to the complexity of transporting students to and from school are first surveyed and, following this, the overall problem is formalized in terms of a system of nodes and links. An analysis of several routing systems…

Richards, Thomas C.

177

School Bus Accidents: Reducing Incidents and Injuries  

ERIC Educational Resources Information Center

The number of children injured in nonfatal school bus accidents annually is more than double the number previously estimated. In Ohio alone, approximately 20,800 children younger than 18 were occupants of school buses that were involved in crashes in 2003 and 2004 (McGeehan 2007). Among those children, most had minor or no injuries. However, there…

Mahoney, Daniel

2009-01-01

178

FUEL CELL BUS DEMONSTRATION IN MEXICO CITY  

EPA Science Inventory

The report discusses the performance of a cull-size, zero-emission, Proton Exchange Membrane (PEM) fuel-cell-powered transit bus in the atmospheric environment of Mexico City. To address the air quality problems caused by vehicle emissions in Mexico City, a seminar on clean vehic...

179

Energy DataBus (Fact Sheet)  

SciTech Connect

NREL has developed the Energy DataBus, an open-sourced software that collects massive amounts of energy-related data at second-to-second intervals; stores it in a massive, scalable database; and turns it into useful information.

Not Available

2013-07-01

180

SDRAM bus schedule of HDTV video decoder  

NASA Astrophysics Data System (ADS)

In this paper, a time division multiplexed task scheduling (TDM) is designed for HDTV video decoder is proposed. There are three tasks: to fetch decoded data from SDRAM for displaying (DIS), read the reference data from SDRAM for motion compensating (REF) and write the motion compensated data back to SDRAM (WB) on the bus. The proposed schedule is based on the novel 4 banks interlaced SDRAM storage structure which results in less overhead on read/write time. Two SDRAM of 64M bits (4Bank×512K×32bit) are used. Compared with two banks, the four banks storage strategy read/write data with 45% less time. Therefore the process data rates for those three tasks are reduced. TDM is developed by round robin scheduling and fixed slot allocating. There are both MB slot and task slot. As a result the conflicts on bus are avoided, and the buffer size is reduced 48% compared with the priority bus scheduling. Moreover, there is a compacted bus schedule for the worst case of stuffing owning to the reduced executing time on tasks. The size of buffer is reduced and the control logic is simplified.

Wang, Hui; He, Yan L.; Yu, Lu

2001-12-01

181

Analysis of commercial mini-bus accidents  

Microsoft Academic Search

This paper presents a study of mini-bus traffic accidents aimed at gaining insight into the factors affecting accident occurrence and severity. Understanding these factors can help to bring forth realistic strategies to improve the safety of these buses. Two disaggregate models related to the time until accident occurrence and the number of accident injuries were specified and estimated. The models

Mohammad M. Hamed; A. S. Jaradat; Said M. Easa

1998-01-01

182

Tel Aviv: Bus Stop on Allenby Street  

Microsoft Academic Search

Allenby Street is a main commercial street in Tel Aviv. It is also a main route on the city bus system. At night, Allenby Street is a destination for nightlife, while during the day it is a busy area for retail shopping. Alleby Street is known for it’s inexpensive shops and adult oriented clubs.

Chet Smolski

1980-01-01

183

Mission Services Evolution Center Message Bus  

NASA Technical Reports Server (NTRS)

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.

Mayorga, Arturo; Bristow, John O.; Butschky, Mike

2011-01-01

184

Bus rapid transit identity meets universal design  

Microsoft Academic Search

As bus rapid transit (BRT) systems continue to become more popular and as capital expenditure for such projects continues to grow, careful consideration of BRT identity design becomes ever more necessary. Properly considered identity systems can ensure accessibility to and usability of physical features and can also ensure that BRT systems are accessible and practical to use. Based on the

Alex Bitterman; Daniel Baldwin Hess

2008-01-01

185

UW Employee Bus Pass Online Ordering Instructions  

E-print Network

or in the wrong order, follow the directions to update your address. Once complete, click "Parking Account Main complete, click "Parking Account Main Home Page". 7. Click "Purchase Permits and Bus Passes". 8. Click. Review payment information, click "Pay Now" and follow the instructions for a credit card payment or pre

Wisconsin at Madison, University of

186

Information management advanced development. Volume 3: Digital data bus breadboard  

NASA Technical Reports Server (NTRS)

The design, development, and evaluation of the digital data bus breadboard for the modular space station are discussed. Subjects presented are: (1) requirements summary, (2) parametric data for bus design, (3) redundancy concepts, and (4) data bus breadboard performance and interface requirements.

Gerber, C. R.

1972-01-01

187

Transit Bus Life Cycle Cost and Year 2007 Emissions Estimation.  

National Technical Information Service (NTIS)

The report presents a study of transit bus life cycle cost (LCC) analysis, and projected transit bus emissions and fuel economy for 2007 model year buses. It covers four bus types: diesel buses using ultra low sulfur diesel (ULSD), diesel buses using B20 ...

D. W. Lyons, F. Zhen, N. N. Clark, W. S. Wayne

2007-01-01

188

75 FR 5847 - Section 5309 Bus and Bus Facilities Livability Initiative and Urban Circulator Program Grants  

Federal Register 2010, 2011, 2012, 2013

...August 10, 2005. The Urban Circulator Program is funded...discretionary Bus Livability and Urban Circulator Programs to February...general information on the Urban Circulator Program contact Elizabeth Day, Office of Planning and Environment,...

2010-02-04

189

46 CFR 120.324 - Dual voltage generators.  

Code of Federal Regulations, 2013 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2013-10-01

190

46 CFR 120.324 - Dual voltage generators.  

Code of Federal Regulations, 2012 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2012-10-01

191

46 CFR 120.324 - Dual voltage generators.  

Code of Federal Regulations, 2011 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2011-10-01

192

46 CFR 120.324 - Dual voltage generators.  

Code of Federal Regulations, 2010 CFR

...SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR...A dual voltage generator installed on a vessel shall be of the grounded type, where...connected to the bus. (c) Ground detection must be provided that: (1) For...

2010-10-01

193

Queue length asymptotics for generalized max-weight scheduling in the presence of heavy-tailed traffic  

E-print Network

We investigate the asymptotic behavior of the steady-state queue length distribution under generalized max-weight scheduling in the presence of heavy-tailed traffic. We consider a system consisting of two parallel queues, ...

Jagannathan

194

58. VIEW OF SIGNAL BUS SECTION NUMBER 2 LOCATED OVER ...  

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

58. VIEW OF SIGNAL BUS SECTION NUMBER 2 LOCATED OVER THE CONTROL ROOM MEZZANINE IN THE SIGNAL POWER CONDITIONING ROOM. BUS IS A HEAVY COPPER BAR APPROXIMATELY 1/2" BY 4" WHICH CONDUCTS POWER THROUGHOUT THE POWER PLANT. BUS ARE PROTECTED BY A BRICK AND SOAPSTONE HOUSING. OPENINGS FOR INSPECTION AND ACCESS WOULD NORMALLY BE PROTECTED BY GLASS DOORS. THE BUS WOULD BE SUPPORTED ON INSULATORS WITHIN THE BRICK CHAMBER. BUS WAS REMOVED AND SALVAGED WHEN THE STATION WAS ABANDONED. THE OBJECT IN THE TOP CENTER OF THE PHOTOGRAPH IS A POTENTIAL TRANSFORMER USED TO REDUCE BUS POTENTIAL OF 2200 VOLTS TO LOW VOLTAGES SAFE FOR USE IN CONTROL ROOM CIRCUITRY. POTENTIAL TRANSFORMERS ARE PRECISION DEVICES WHICH PRODUCE AN ACCURATE LOW VOLTAGE ANALOG OF THE HIGH VOLTAGE ON THE BUS. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

195

Isolated ARQ Queue with ARQ ARQ in Downlink ARQ in MANETs Reliability by Retransmissions in the Wireless  

E-print Network

Isolated ARQ Queue with ARQ ARQ in Downlink ARQ in MANETs Reliability by Retransmissions by Retransmissions in the Wireless World #12;Isolated ARQ Queue with ARQ ARQ in Downlink ARQ in MANETs Outline 1 Isolated ARQ 2 Queue with ARQ 3 ARQ in Downlink 4 ARQ in MANETs Anastasios Giovanidis Reliability

Gesbert, David

196

A Binary Channel with Additive Bursty Noise Based on a Finite Queue  

E-print Network

of Mathematics and Statistics and the School of Graduate Studies for their #12;nancial assistance over the past this study. My special thanks are due to Hongyan Kuai and other members in the Communica- tion Group cases: a uniform queue-based mode where we experiment on the cells of the queue with equal probability

Alajaji, Fady

197

EFFECTIVE BANDWIDTHS AT MULTI-CLASS QUEUES Statistical Laboratory, University of Cambridge, 16 Mill Lane,  

E-print Network

of the queue. Keywords: large deviations, M/G/1 queue, circuit-switched network, connection acceptance control. 1. Introduction The traditional model of a circuit-switched network assumes that each link k, the probability of resource overload can be held below a desired level by requiring that the number of calls nj

Kelly, Frank

198

Queueing Network-Model Human Processor (QN-MHP): A Computational Architecture for  

E-print Network

approaches to cognitive modeling: the queueing network approach and the symbolic approach (exemplified by the MHP/GOMS family of models, ACT-R, EPIC, and SOAR). Queueing networks are particularly suited concurrent manner. QN-MHP expands the three discrete serial stages of MHP, of perceptual, cognitive

Liu, Yili

199

Adaptive RED: An Algorithm for Increasing the Robustness of RED's Active Queue Management  

E-print Network

Adaptive RED: An Algorithm for Increasing the Robustness of RED's Active Queue Management Sally, under submission Abstract The RED active queue management algorithm allows net- work operators is quite sensitive to the level of congestion and to the RED parameter settings, and is therefore not pre

Floyd, Sally

200

Adaptive RED: An Algorithm for Increasing the Robustness of RED's Active Queue Management  

E-print Network

Adaptive RED: An Algorithm for Increasing the Robustness of RED's Active Queue Management Sally, under submission Abstract The RED active queue management algorithm allows net­ work operators is quite sensitive to the level of congestion and to the RED parameter settings, and is therefore not pre

Floyd, Sally

201

Queueing Theory for Semiconductor Manufacturing Systems: A Survey and Open Problems  

Microsoft Academic Search

This paper surveys applications of queueing theory for semiconductor manufacturing systems (SMSs). Due to sophisticated tool specifications and process flows in semiconductor manufacturing, queueing models can be very complicated. Research efforts have been on the improvement of model assumptions and model input, mainly in the first moment (averages) and the second moment (variations). However, practices show that implementation of classical

J. George Shanthikumar; Shengwei Ding; Mike Tao Zhang

2007-01-01

202

On the distribution of the number of customers in the symmetric M/G/1 queue  

E-print Network

moment of time the M/G/1 LCFS queue and PS queue coincide in distribution , i.e. QPS t =D QLCFS be the Laplace-Stieltjes transform (LST) of the service distribution B1 and define the net input process Y (t problem to the analysis of an embe

203

Queueing Systems 42, 325353, 2002 2002 Kluwer Academic Publishers. Manufactured in The Netherlands.  

E-print Network

in The Netherlands. A Communication Multiplexer Problem: Two Alternating Queues with Dependent Randomly-Timed Gated there depends on the arrival stream to the primary queue. We derive Laplace­Stieltjes transforms and generating at polling instants and at an arbitrary moment, mean busy period duration and mean cycle time length

Fibich, Gadi

204

Finite-Buffer Queues with Workload-Dependent Service and Arrival Rates  

E-print Network

Finite-Buffer Queues with Workload-Dependent Service and Arrival Rates Ren´e Bekker email: rbekker of the workload in two finite-buffer models, in which the ratio of arrival and service speed is equal. Second, we of restricted accessibility. The proportionality relation be- tween some finite and infinite-buffer queues

205

REDWorcester --Traffic Sensitive Active Queue Management Vishal Phirke, Mark Claypool, Robert Kinicki  

E-print Network

RED­Worcester -- Traffic Sensitive Active Queue Management Vishal Phirke, Mark Claypool, Robert of Service (QoS) 1 adapted to the current traffic mix. Most Active Queue Management (AQM) techniques|claypool|rekg@cs.wpi.edu 1 Introduction The Internet today carries traffic for applications with a wide range of delay

Kinicki, Robert E.

206

Queueing Systems 13(1993)291-314 291 A survey of Markov decision models for control  

E-print Network

of queues, consider a data communication network. Whether operating under packet switching or virtual-circuit switching, such a network can often be modelled as a network of queues. The messages or packets generated, digital switches. As an illustration of how optimal control models can be used in applications of networks

Weber, Richard

207

Q-Sim: a GUI for a queueing simulator using Tcl\\/Tk  

Microsoft Academic Search

A design and implementation are presented for a graphical user interface to a batch queueing simulator, illustrating the benefits of using a high-level script language. Rapid development was made possible with the use of Tcl\\/Tk scripts to implement the entire interface. The script implements a dynamic display of job and queue movement along with graphs of statistical behaviors. A message

Edward A. Billard; Alice E. Riedmiller

1994-01-01

208

Applications of dynamic games in queues INRIA, 2004 route des Lucioles, 06902 Sophia Antipolis, France  

E-print Network

of losses or large delay variations are quite harmful in real time voice and video applications. 1 #12Applications of dynamic games in queues E. Altman INRIA, 2004 route des Lucioles, 06902 Sophia to many challenging problems in dynamic games. We shall describe in this overview some generic queueing

209

HEAVY-TRAFFIC EXTREME-VALUE LIMITS FOR QUEUES Peter W. Glynn  

E-print Network

HEAVY-TRAFFIC EXTREME-VALUE LIMITS FOR QUEUES by Peter W. Glynn Department of Operations Research-value distributions depend upon the queueing processes, and thus the model data, in a complicated way. Berger parameters. In particular, Berger and Whitt [6] developed and evaluated several heuristic approximations

Whitt, Ward

210

Queueing Analysis and Delay Mitigation in IEEE 802.11 Random Access MAC based Wireless Networks  

Microsoft Academic Search

In this paper, we present an analytic model for evaluating the queueing delays at nodes in an IEEE 802.11 MAC based wireless network. The model can account for arbitrary arrival patterns, packet size distributions and number of nodes. Our model gives closed form expressions for obtaining the delay and queue length characteristics. We model each node as a discrete time

Omesh Tickoo; Biplab Sikdar

2004-01-01

211

A Resource-Allocation Queueing Fairness Measure School of Computer Science  

E-print Network

A Resource-Allocation Queueing Fairness Measure David Raz School of Computer Science Tel-Aviv University, Tel-Aviv, Israel davidraz@post.tau.ac.il Hanoch Levy School of Computer Science Tel, NJ, USA aviitzha@rutcor.rutgers.edu ABSTRACT Fairness is a major issue in the operation of queues

Levy, Hanoch

212

Fair Operation of Multi-Server and Multi-Queue Systems School of Computer Science  

E-print Network

Fair Operation of Multi-Server and Multi-Queue Systems David Raz School of Computer Science Tel Brunswick, NJ, USA aviitzha@rutcor.rutgers.edu Hanoch Levy School of Computer Science Tel-Aviv University, computer systems). One of the ma- jor motivations behind common queue operation strategies is to grant fair

Levy, Hanoch

213

Ramp Metering by Limitation of Density and Queue Length  

NASA Astrophysics Data System (ADS)

As shown by many works and studies, the control of traffic flow remains the best and the efficient solution of the congestion problems. The ramp metering is a means to reduce congestion effects, it has shown his effectiveness to improve the flow and consequently to reduce the total time spent (TTS) by the vehicles in the network. In Kamel et al. [2008] the concept of flatness-based control was applied to regulate the flow at the mainline section of the road on the traffic flow model LWR. This work was preceded by Abouaïssa et al. [2006]. In this article we have proceeded the same way to set the flat output for a second order model METANET. Unfortunately we were unable to prove that the system is flat and therefore define density as flat output, but we manage to define the control laws in order to respect constraints on density and queue length at the on-ramp. The idea is to express the control variable (the outflow of the on-ramp) according to the output (density or queue length at the on-ramp), then inject it in the system. We use this control method in the ramp metering case. The first aim of the control is to keep the density in the segment where the on-ramp is connected below a density (called the target density YT) for which we have the lowest TTS, and the second aim is to keep the queue length at the on-ramp below a maximum value. In order to evaluate the controller's efficiency and applicability, a comparison is made with traditional ALINEA based controller. We illustrate this approach by comparing the cases 'no control' and 'ramp metering' for a simple network.

Kamel, Boumediene; Benasser, Amar; Jolly, Daniel

2009-03-01

214

OPC-Friendly Bus Driven Floorplanning  

Microsoft Academic Search

In this paper, we address the interconnect-driven floorplan ning prob- lem that integrates OPC-friendly bus assignment with floorp lan- ning. Buses consist of a number of horizontal\\/vertical wires with identical widths. The positions of buses must be carefully designed so that the related blocks can connect to the buses with short con- nections. Meanwhile, as technologies march into deep sub-micron,

Hua Xiang; Liang Deng; Li-da Huang; Martin D. F. Wong

2007-01-01

215

Exposure assessment of diesel bus emissions.  

PubMed

The goal of this study was to measure ultrafine particle concentrations with diameters less than 1 mum emitted by diesel buses and to assess resulting human exposure levels. The study was conducted at the Woolloongabba Busway station in Brisbane, Australia in the winter months of 2002 during which temperature inversions frequently occurred. Most buses that utilize the station are fuelled by diesel, the exhaust of which contains a significant quantity of particle matter. Passengers waiting at the station are exposed to these particles emitted from the buses. During the course of this study, passenger census was conducted, based on video surveillance, yielding person-by-person waiting time data. Furthermore, a bus census revealed accurate information about the total number of diesel versus Compressed Natural Gas (CNG) powered buses. Background (outside of the bus station) and platform measurements of ultrafine particulate number size distributions were made to determine ambient aerosol concentrations. Particle number exposure concentration ranges from 10 and 40 to 60% of bus related exhaust fumes. This changes dramatically when considering the particle mass exposure concentration, where most passengers are exposed to about 50 to 80% of exhaust fumes. The obtained data can be very significant for comparison with similar work of this type because it is shown in previous studies that exhaust emissions causes cancer in laboratory animals. It was assumed that significant differences between platform and background distributions were due to bus emissions which, combined with passenger waiting times, yielded an estimate of passenger exposure to ultrafine particles from diesel buses. From an exposure point of view, the Busway station analyzed resembles a street canyon. Although the detected exhaust particle concentration at the outbound platform is found to be in the picogram range, exposure increases with the time passengers spend on the platform along with their breathing frequency. PMID:17159271

Yip, Maricela; Madl, Pierre; Wiegand, Aaron; Hofmann, Werner

2006-12-01

216

The Robo-AO automated intelligent queue system  

NASA Astrophysics Data System (ADS)

Robo-AO is the first automated laser adaptive optics instrument. In just its second year of scientific operations, it has completed the largest adaptive optics surveys to date, each comprising thousands of targets. Robo-AO uses a fully automated queue scheduling system that selects targets based on criteria entered on a per observing program or per target basis, and includes the ability to coordinate with US Strategic Command automatically to avoid lasing space assets. This enables Robo-AO to select among thousands of targets at a time, and achieve an average observation rate of approximately 20 targets per hour.

Riddle, Reed L.; Hogstrom, Kristina; Papadopoulos, Athanasios; Baranec, Christoph; Law, Nicholas M.

2014-07-01

217

The Robo-AO automated intelligent queue system  

E-print Network

Robo-AO is the first automated laser adaptive optics instrument. In just its second year of scientific operations, it has completed the largest adaptive optics surveys to date, each comprising thousands of targets. Robo-AO uses a fully automated queue scheduling system that selects targets based on criteria entered on a per observing program or per target basis, and includes the ability to coordinate with US Strategic Command automatically to avoid lasing space assets. This enables Robo-AO to select among thousands of targets at a time, and achieve an average observation rate of approximately 20 targets per hour.

Riddle, Reed L; Papadopoulos, Athanasios; Baranec, Christoph; Law, Nicholas M

2014-01-01

218

Dual diagnosis  

Microsoft Academic Search

Dual diagnosis denotes the co-occurrence of severe mental illness and substance use disorder. This contribution summarizes the literature on dual diagnosis by reviewing epidemiology, phenomenology, clinical correlates, assessment, treatment and current research. Epidemiological data from several countries show that substance abuse or dependence is common (approximately 50%) among persons disabled by severe mental disorders such as schizophrenia, bipolar disorder or

Robert E. Drake

2007-01-01

219

MIL-STD-1553 dual redundant remote terminal superhybrid  

NASA Astrophysics Data System (ADS)

This paper describes the performance, physical and electrical characteristics of the BUS-65112 Superhybrid, which performs as a fully compliant MIL-STD-1553 Dual Redundant Remote Terminal Unit (RTU). A discussion of the Custom Monolithic LSI components implemented in the Superhybrid is included. The RTU's special features and capabilities is highlighted, along with special programming options which facilitate a broad array of applications. The BUS-65112 Superhybrid contains all the necessary control lines to allow easy Direct Memory Access (DMA). The interface timing, operational philosophy, and a block diagram highlighting the Superhybrid's functional architecture are included.

Friedman, S. N.

220

Queueing up for enzymatic processing: correlated signaling through coupled degradation  

PubMed Central

High-throughput technologies have led to the generation of complex wiring diagrams as a post-sequencing paradigm for depicting the interactions between vast and diverse cellular species. While these diagrams are useful for analyzing biological systems on a large scale, a detailed understanding of the molecular mechanisms that underlie the observed network connections is critical for the further development of systems and synthetic biology. Here, we use queueing theory to investigate how ‘waiting lines' can lead to correlations between protein ‘customers' that are coupled solely through a downstream set of enzymatic ‘servers'. Using the E. coli ClpXP degradation machine as a model processing system, we observe significant cross-talk between two networks that are indirectly coupled through a common set of processors. We further illustrate the implications of enzymatic queueing using a synthetic biology application, in which two independent synthetic networks demonstrate synchronized behavior when common ClpXP machinery is overburdened. Our results demonstrate that such post-translational processes can lead to dynamic connections in cellular networks and may provide a mechanistic understanding of existing but currently inexplicable links. PMID:22186735

Cookson, Natalie A; Mather, William H; Danino, Tal; Mondragon-Palomino, Octavio; Williams, Ruth J; Tsimring, Lev S; Hasty, Jeff

2011-01-01

221

New active queue management mechanism for Web traffic  

NASA Astrophysics Data System (ADS)

In this work, we devise and study the performance of a new active queue management mechanism for Web traffic to more intelligently select packets to drop incipient of network congestion. The proposed mechanism specifically targets short-lived or fragile flows (e.g., most HTTP flows) to keep link utilization high while reducing the HTTP response time. The goal of the proposed active queue management scheme is to protect new TCP flows and TCP flows that have packet dropped recently from potential network congestion, thus achieving better response times. Our simulation studies have compared the performance of RED and the proposed AQM for a network with only HTTP traffic at loads less, close to, and more than the network capacity. Simulations show that a subsidy given to a flow that that is in its initial stage provides significantly better performance in terms of HTTP request-reply delays without sacrificing the link utilization. The new scheme is very simple to implement. It contains one additional control parameter to RED, and the tuning of this parameter is simple. Since most HTTP flows are short-lived, only the state information for a subset of active flows needs to be maintained for a very short period of time, and then all the resources used for keeping the state information can be reclaimed.

Kasthurirangan, Badri; Wang, Bin; Xu, J.

2002-07-01

222

A multiprocessor bus architecture for the LEP control system  

SciTech Connect

The architecture and the system aspects of the multi-master bus used for the construction of the process computer assemblies and the message handling assemblies of the LEP control system are presented. This bus architecture provides a fully distributed reservation mechanism and a protected access of the peripherals to prevent processor interferences. To achieve this, a channel concept is proposed, using a system bus for communication between processors and with their peripherals. The architecture is microprocessor independent, provides dynamic bus allocation amongst several microcomputers, offers processor position independence and has a multimaster bus extension to several crates with a homogeneous addressing. A global system concept, called E3S, has been developed including the definition of software primitives. The bus access software is organised in a layered structure matching the module functionality.

Altaber, J.; Rausch, R.

1983-08-01

223

Optimal routing and buffer allocation for a class of finite capacity queueing systems  

NASA Technical Reports Server (NTRS)

The problem of routing jobs to K parallel queues with identical exponential servers and unequal finite buffer capacities is considered. Routing decisions are taken by a controller which has buffering space available to it and may delay routing of a customer to a queue. Using ideas from weak majorization, it is shown that the shorter nonfull queue delayed (SNQD) policy minimizes both the total number of customers in the system at any time and the number of customers that are rejected by that time. The SNQD policy always delays routing decisions as long as all servers are busy. Only when all the buffers at the controller are occupied is a customer routed to the queue with the shortest queue length that is not at capacity. Moreover, it is shown that, if a fixed number of buffers is to be distributed among the K queues, then the optimal allocation scheme is the one in which the difference between the maximum and minimum queue capacities is minimized, i.e., becomes either 0 or 1.

Towsley, Don; Sparaggis, Panayotis D.; Cassandras, Christos G.

1992-01-01

224

TMS communications hardware. Volume 2: Bus interface unit  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

225

Characteristics of rainfall queues for rain attenuation studies over radio links at subtropical and equatorial Africa  

NASA Astrophysics Data System (ADS)

due to precipitation remains an important design factor in the future deployment of terrestrial and earth-space communication radio links. Largely, there are concerted efforts to understand the dynamics of precipitation in attenuation occurrence at subtropical, tropical, and equatorial region of Africa. In this deliberate approach, rainfall spikes pertaining to rain cells are conceptualized as distinct rain spike traffic over radio links, by applying queueing theory concepts. The queue distributions at Durban (29°52'S, 30°58'E) and Butare (2°36'S, 29°44'E)—respectively, of subtropical and equatorial climates—are investigated from distrometer measurements. The data sets at both sites are observed over four rain regimes: drizzle, widespread, shower, and thunderstorm. The queue parameters of service time and inter-arrival of rain spikes traffic at both regions are found to be Erlang-k distributed (Ek) and exponentially distributed (M), respectively. It is established that the appearance of rain rates over radio links invariably follows a First Come, First Served (FCFS), multi-server (s), infinite queue, and semi-Markovian process, designated as M/Ek/s/?/FCFS discipline. Modeled queue parameters at both regions are found to vary significantly over different regimes. However, these queue parameters over the entire data set suggest similar queue patterns at both sites. More importantly, power law relationships describing other queue-related parameters are formulated. The paper concludes by demonstrating an application of queueing theory for rainfall synthesis. The proposed technique will provide an alternative method of estimating rain cell sizes and rain attenuation over satellite and terrestrial links.

Alonge, Akintunde A.; Afullo, Thomas J.

2014-08-01

226

The Simulation of MRT Transfer System Based on Bus Holding Strategies with platform constraints  

Microsoft Academic Search

This research aims at the bus holding strategies for the simulation of mass rapid transit (MRT) transferring system in a terminal station with platform constraints for bus in the metropolitan area. We developed and evaluated the transfer system through computer simulation models for MRT with bus system that the goals of bus holding strategies in the model were: reduce bus

Shih-Che Lo; Wei-Jie Chang; Peng-Cheng Kuo; Chun-Yun Kuo

2009-01-01

227

The SMART MIL-STD-1553 bus adapter hardware manual  

NASA Technical Reports Server (NTRS)

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.

Ton, T. T.

1981-01-01

228

Reliable Fiber Sensor System with Star-Ring-Bus Architecture  

PubMed Central

This work presents a novel star-ring-bus sensor system and demonstrates its effectiveness. The main trunk of the proposed sensor system is a star topology and the sensing branches comprise a series of bus subnets. Any weakness in the reliability of the sensor system is overcome by adding remote nodes and switches to the ring and bus subnets. To construct the proposed star-ring-bus sensor system, a fiber ring laser scheme is used to improve the signal-to-noise ratio of the sensor system. The proposed system increases the reliability and capacity of fiber sensor systems. PMID:22399876

Peng, Peng-Chun; Wang, Jun-Bo; Huang, Kuan-Yan

2010-01-01

229

Enhancement of VoIP over IEEE 802.11 WLAN via Dual Queue Strategy  

E-print Network

-real-time (NRT) data services like Web browsing, e-mail, and file transfer. Recently, the needs for real-time (RT Telecom tasmea@kt.co.kr Abstract- Today's IEEE 802.11 Wireless LAN (WLAN) is an excellent solution

Choi, Sunghyun

230

Stochastic analyses arising from a new approach for closed queueing networks  

E-print Network

is presented to calculate the system size distribution at an arbitrary point in time and at departures for a ?(n)/G/1/N queue. The analysis is carried out using an embedded Markov chain approach. An algorithm is also developed that combines our analysis... functions of the SM/PH/1/N queue by using the matrix-analytic method. Closed form results iv are also obtained for particular situations of the preceding queue. In addition, it is demonstrated that the SM/PH/1/N model can be implemented to the analysis of a...

Sun, Feng

2009-05-15

231

Spaceborne Fiber Optic Data Bus (SFODB)  

NASA Technical Reports Server (NTRS)

Spaceborne Fiber Optic Data Bus (SFODB) is an IEEE 1393 compliant, gigabit per second, fiber optic network specifically designed to support the real-time, on-board data handling requirements of remote sensing spacecraft. The network is fault tolerant highly reliable, and capable of withstanding the rigors of launch and the harsh space environment. SFODB achieves this operational and environmental performance while maintaining the small size, light weight, and low power necessary for spaceborne applications. On December 9, 1998, SFODB was successfully demonstrated at NASA's Goddard Space Flight Center (GSFC).

Bretthauer, Joy W.; Chalfant, Chuck H.; Orlando, Fred J.; Parkerson, P.; Rezek, Ed; Sawyer, Marc

1999-01-01

232

Laboratory Schools 2011/2012 Bus Itinerary  

E-print Network

:15 p.m. 2:15 p.m. West end parking lot at Diversey 4:12 p.m. 3:22 p.m. and Inner LSD near St. Joe's 3 Hancock Bldg. - Delaware side 4:35 p.m. 3:45 p.m. 3:40 p.m. 2:40 p.m. 680 N. LSD (front entrance, east or Lab After School Special Classes New U-High Schedule Impact: On Tuesday and Friday, a third bus

Scherer, Norbert F.

233

Managing Student Behavior on the School Bus: A Key to Bus Safety  

ERIC Educational Resources Information Center

School buses are the safest form of mass transit in America. Every day, school buses travel through congested city traffic and on isolated country roads in all types of weather, safely transporting millions of children to and from school and school-related activities. Federal and state standards for school bus construction and maintenance and…

American Federation of Teachers (NJ), 2007

2007-01-01

234

Peer-to-Peer Information Exchange on Bus Rapid Transit (BRT) and Bus Priority Best Practices  

Microsoft Academic Search

The purpose of this effort was to foster a dialogue among peers at transportation and planning agencies about their experiences with promoting public transit and, in particular, the challenges they face related to Bus Rapid Transit (BRT) projects, as well as the solutions they have developed in response. Agencies from dozens of large cities around the United States participated at

Marta Panero; Hyeon-Shic Shin; Allen Zedrin; Samuel Zimmerman

2012-01-01

235

Optoelectronic design of the simultaneous optical multiprocessor exchange bus (SOME-Bus)  

NASA Astrophysics Data System (ADS)

Low latency, high bandwidth interconnecting networks that directly link arbitrary pairs of processing elements without contention are very desirable for parallel computers. The simultaneous optical multiprocessor exchange bus (SOME-Bus) based on a fiber optic interconnect is such a network. The SOME-Bus provides a dedicated channel for each processor for data output and thus eliminates global arbitration. Each processor can receive data simultaneously from all other processors in the system using an array of receivers. The architecture allow for simultaneous multicast and broadcast messages using several processors with zero setup time and no global scheduling. In this paper, we discuss the design of a possible opto-electronic implementation of the SOME-Bus along with an optical power budget analysis. Slant Bragg fiber grains arranged to couple light out of a fiber ribbon cable into an array of amorphous silicon detectors vertically integrated on a silicon are presented as a low cost novel means of interconnecting 10 to 120 processors.

Lindquist, Robert G.; Kulick, Jeffrey H.; Cohen, Will E.; Gaede, Rhonda K.; Wells, B. Earl; Abushagur, Mustafa A. G.; Shen, Dashen; Katsinis, Constantine; Kowel, Stephen T.

1997-04-01

236

Measurement of light capture in solar cells from silver- and tin-plated patterned bus bars  

E-print Network

Bus bars on solar cells shade silicon from light. When the bus bars are patterned, they can reflect light back onto the silicon using total internal reflection. These patterned bus bars are tin plated and produce 1-2.5% ...

Winiarz, Christine Eve

2007-01-01

237

An advanced time-dependent queueing model for airport delay analysis  

E-print Network

Introduction: In the past several years many attempts have been made to model the probabilistic nature of airport runway operations using a queueing-theoretic approach to runway modeling. Early studies were limited by ...

Roth, Emily Jane

1979-01-01

238

Improvements to a queue and delay estimation algorithm utilized in video imaging vehicle detection systems  

E-print Network

Video Imaging Vehicle Detection Systems (VIVDS) are steadily becoming the dominant method for the detection of vehicles at a signalized traffic approach. This research is intended to investigate the improvement of a queue and delay estimation...

Cheek, Marshall Tyler

2007-09-17

239

Scheduling Networks of Queues: Heavy Traffic Analysis of a Multistation Closed Network  

E-print Network

We consider the problem of finding an optimal dynamic priority sequencing policy to maximize the mean throughput rate in a multistation, multiclass closed queueing network with general service time distributions and a ...

Chevalier, Philippe B.

240

Commuting matrices in the sojourn time analysis of MAP/MAP/1 queues  

E-print Network

MAP, as its evolution can be cap- tured by means of a Quasi-Birth-Death Markov chain [10]. The sojourn- Birth-Death (QBD) queues [12] and proved that it has a matrix exponential representation of order N2

Telek, Miklós

241

An N Server Cutoff Priority Queue Where Customers Request a Random Number of Servers  

E-print Network

Consider a multi-priority, nonpreemptive, N-server Poisson arrival queueing system. The number of servers requested by an arrival has a known probability distribution. Service times are negative exponential. In order to ...

Schaack, Christian

242

Network Engineering of Elastic Data Tra#c via Tandem Queueing Network Models  

E-print Network

Network Engineering of Elastic Data Tra#c via Tandem Queueing Network Models A. W. Berger 1 , E. G is long­range dependent. The tandem CQN models are motivated by the following network engineering scenario

Coffman Jr., E. G.

243

Analyzing the make-to-stock queue in the supply chain and eBusiness settings  

E-print Network

This thesis presents two applications of the prototypical make-to-stock queue model that are mainly motivated by supply chain management and e-commerce issues. In the first part, we consider the decentralized version of ...

Caldentey, René

2001-01-01

244

An Analysis of Double Queue on PRT System and a Control Strategy for Merging  

NASA Astrophysics Data System (ADS)

This paper deals with a merging section of Personal Rapid Transit system. Several schemes have been proposed for the control of vehicles in PRT systems. In quasi-synchronous control systems, one flow of traffic must form a queue at a merging section in order to avoid the collision of vehicles. In other words, a queue is formed on one of the lines, which is called the sub line; the other line is called the main line. Basically, vehicles on the main line have priority. We propose a control strategy whereby vehicles on the main line are usually not stopped; vehicles on the main line are only stopped when the number of waiting vehicles on the sub line exceeds some specific number. Therefore, queues are formed on the main line and the sub line, respectively. This paper presents a fundamental discussion of the effects of the double queue and the relationship between traffic density and the behavior of traffic.

Kai, Cao; Matsuda, Ryuta; Yano, Youhei; Hamamatsu, Yoshio

245

Battery management system for series-hybrid electric shuttle bus  

Microsoft Academic Search

In this paper, a battery management system (BMS) of a lead-acid battery pack for a series hybrid electric vehicle (SHEV) shuttle bus is presented. The BMS is a necessary component for an optimal operation of power-train in the SHE V shuttle bus including for timely detection of an abnormal condition during charging and discharging the battery pack. The presented BMS

Teerayut Piboonrujananon; Nisai H. Fuengwarodsakul

2011-01-01

246

A multidisciplinary approach toward improving bus schedule readability  

Microsoft Academic Search

Printed schedules are critical to mass transit mobility, perhaps no more so than to bus transit users who often embark from locations where information is not provided. For economic reasons, they also rely heavily on transit. Schedules are their lifeline. After becoming concerned with the readability of its bus schedules, New Jersey Transit (NJT) enlisted an interdisciplinary research and design

Darius Sollohub; Anand Tharanathan

2006-01-01

247

Network Extender for MIL-STD-1553 Bus  

NASA Technical Reports Server (NTRS)

An extender system for MIL-STD-1553 buses transparently couples bus components at multiple developer sites. The bus network extender is a relatively inexpensive system that minimizes the time and cost of integration of avionic systems by providing a convenient mechanism for early testing without the need to transport the usual test equipment and personnel to an integration facility. This bus network extender can thus alleviate overloading of the test facility while enabling the detection of interface problems that can occur during the integration of avionic systems. With this bus extender in place, developers can correct and adjust their own hardware and software before products leave a development site. Currently resident at Johnson Space Center, the bus network extender is used to test the functionality of equipment that, although remotely located, is connected through a MILSTD- 1553 bus. Inasmuch as the standard bus protocol for avionic equipment is that of MIL-STD-1553, companies that supply MIL-STD-1553-compliant equipment to government or industry and that need long-distance communication support might benefit from this network bus extender

Marcus, Julius; Hanson, T. David

2003-01-01

248

Measuring the effects of built environment on bus stop crime  

Microsoft Academic Search

There has been considerable interest in recent decades in the identification of the physical correlates of crime in different urban settings. In this study we focus on bus stop crime and seek to understand how different environmental attributes in the vicinity of a bus stop can affect the incidence of crime. We first review evidence from the relevant literature to

Anastasia Loukaitou-Sideris; Robin Liggett; Hiroyuki Iseki; William Thurlow

2001-01-01

249

OneBusAway: Improving the Usability of Public Transit  

E-print Network

OneBusAway: Improving the Usability of Public Transit Brian Ferris A dissertation submitted;#12;University of Washington Abstract OneBusAway: Improving the Usability of Public Transit Brian Ferris Public of the community, while at the same time combating traffic congestion, reducing carbon emissions, and promoting

Anderson, Richard

250

Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Preliminary Evaluation Results  

SciTech Connect

This report provides preliminary results from a National Renewable Energy Laboratory evaluation of a protoptye fuel cell transit bus operating at Connecticut Transit in Hartford. Included are descriptions of the planned fuel cell bus demonstration and equipment; early results and agency experience are also provided.

Chandler, K.; Eudy, L.

2008-10-01

251

Power Electric Aiding Controller for Automated Bus Stopping  

E-print Network

Power Electric Aiding Controller for Automated Bus Stopping Jorge Godoy, Vicente Milanés, Joshue-CSIC {jorge.godoy, vicente.milanes, joshue.perez, jorge.villagra, carlos.gonzalez}@car.upm-csic.es Abstract bus lanes, electrical and hydrogen buses and rail-guided buses have been tested and implemented

Paris-Sud XI, Université de

252

An Investigation Into Aspects of Bus Design and Passenger Requirements  

Microsoft Academic Search

A two part investigation was undertaken by Leyland Vehicles Human Factors Group under contract to the Transport and Road Research Laboratory.Phase 1 of the project covered the physical capabilities of passengers and their design preferences, using a static wooden mock up of a bus floor layout and 200 elderly and disabled subjects. From a questionnaire on problems with bus usage,

B. M. BROOKS

1979-01-01

253

School Bus Driver Instructional Program. Instructor's Guide--Advanced Unit.  

ERIC Educational Resources Information Center

Geared to behavioral objectives, the instruction is organized into programed units on emergency driving techniques, first aid, field trips, transporting exceptional students, detecting hazards, controlling the position of the bus, driving under special conditions, and preventive maintenance of the bus. Each unit is constructed around content…

Department of Transportation, Washington, DC. National Highway Safety Bureau.

254

Red Line/Cedar Avenue Bus Rapid Transitway  

E-print Network

implementa?on ?melines than other transitway investments · BRT provides flexibility?on of dedicated bus shoulder lanes in Apple Valley and Lakeville § Use exis?ng bus shoulder facili?es on TH 77 CR 42 and Cedar Avenue #12;Weekday Transitway Service

Minnesota, University of

255

Evaluation of ITS Technology for Bus Transit Systems  

Microsoft Academic Search

Recently, bus transit service providers have begun to adopt Intelligent Transportation Systems (ITS) technologies such as Global Positioning Systems (GPS) and Mobile Data Terminals. These systems taken together have the potential to reduce the cost of providing transportation services through the execution of real-time control strategies, performance monitoring systems and data collection to support service realignment. We evaluate bus control

Randolph Hall; Maged Dessouky; Lei Zhang; Ajay Singh; Vishal Patell

1999-01-01

256

On self-similar traffic in ATM queues: definitions, overflow probability bound, and cell delay distribution  

Microsoft Academic Search

Recent traffic measurements in corporate LANs, Variable-bit-rate video sources, ISDN control-channels and other communication systems, have indicated traffic behaviour of self-similar nature. This paper first discusses some definitions and properties of (second-order) self-similarity and gives simpler criteria for it. It then gives a model of self-similar traffic suitable for queueing system analysis of an ATM queue. A lower bound to

Boris Tsybakov; Nicoals D. Georganas

1997-01-01

257

Packet loss characteristics for M\\/G\\/1\\/N queueing systems  

Microsoft Academic Search

In this contribution we investigate higher-order loss characteristics for M\\/G\\/1\\/N queueing systems. We focus on the lengths of the loss and non-loss periods as well as on the number of arrivals during these\\u000a periods. For the analysis, we extend the Markovian state of the queueing system with the time and number of admitted arrivals\\u000a since the instant where the last

Dieter Fiems; Stijn De Vuyst; Sabine Wittevrongel; Herwig Bruneel

2009-01-01

258

Development of Traffic Control and Queue Management Procedures for Oversaturated Arterials  

Microsoft Academic Search

The formulation and solution of a new algorithm for queue management and coordination of traffic signals along oversaturated arterials are pre- sented. Existing traffic-control and signal-coordination algorithms deal only with undersaturated steady-state traffic flow conditions. No prac- tical algorithms are readily available for oversaturated flow conditions. The main idea of the procedure is to manage queue formation and dis- sipation

Ghassan Abu-Lebdeh; Rahim F. B Enekohal

1997-01-01

259

A Note on the Influence of Variability in Make-to-Stock Queues Zied Jema*  

E-print Network

A Note on the Influence of Variability in Make-to-Stock Queues Zied Jemaï* and Fikri Karaesmen of inter-arrival time variability in a GI/M/1 Make-to-Stock queue. The primary result therein is an ordering of optimal base stock levels and costs. In particular, it is shown that when two GI/M/1 make-to-stock

Karaesmen, Fikri

260

Queueing models of optical delay lines in synchronous and asynchronous optical packet-switching networks  

Microsoft Academic Search

Buffering with optical delay lines (ODLs) in optical packet- switching networks is a way to mitigate network contention. We study queueing models of ODLs in synchronous and asynchronous optical packet-switching networks under uniform Bernoulli traffic. We first intro- duce a Markov chain model for a finite-length ODL forward-buffering system in synchronized networks and calculate the stationary distribution of its queueing

Xiaoming Zhu; Joseph M. Kahn

2003-01-01

261

Input Versus Output Queueing on a Space-Division Packet Switch  

Microsoft Academic Search

Two simple models of queueing on anN times Nspace-division packet switch are examined. The switch operates synchronously with fixed-length packets; during each time slot, packets may arrive on any inputs addressed to any outputs. Because packet arrivals to the switch are unscheduled, more than one packet may arrive for the same output during the same time slot, making queueing unavoidable.

M. J. Karol; M. G. Hluchyj; S. P. Morgan

1987-01-01

262

The Fairchild MIL-STD-1553 Serial Multiplex Bus Tester  

NASA Astrophysics Data System (ADS)

The Fairchild Serial Multiplex Bus Tester (SMBT) is a general purpose computer controlled MIL-STD-1553 stimulus/response/analyzer. SMBT has been selected to fulfill the data bus testing requirements of the Air Force Modular Automatic Test Equipment (MATE) systems. The design is three separate devices or functions: a monitor, a bus controller, and a remote terminal simulator, which may be operated in any combination. The purpose is to integrate the Monitor, Controller, and Remote Terminal functions into a single unit. SMBT may be controlled and synchronized by a master computer performing a coordinated total checkout of a unit under test. The monitor allows a collection of 1024 word 'windows' of bus traffic and simultaneously accumulate error statistics in all bus traffic. A system self check is incorporated as an additional feature of the design. In summary, the SMBT is designed to provide necessary stimulus, response and analysis capability for MIL-STD-1553 Line Replaceable Unit (LRU) testing.

Dunn, A. M.

263

BurbankBus' clean fuel fleet now includes a zero-emission hydrogen-fueled bus. BurbankBus, which provides transit  

E-print Network

; supplemental charging is provided by two 16-kilowatt Hydrogenics fuel cell power modules and by regenerative braking while the bus is in operation. The battery pack and fuel cells are controlled by on

264

A novel fair active queue management algorithm based on traffic delay jitter  

NASA Astrophysics Data System (ADS)

In order to guarantee the quantity of data traffic delivered in the network, congestion control strategy is adopted. According to the study of many active queue management (AQM) algorithms, this paper proposes a novel active queue management algorithm named JFED. JFED can stabilize queue length at a desirable level by adjusting output traffic rate and adopting a reasonable calculation of packet drop probability based on buffer queue length and traffic jitter; and it support burst packet traffic through the packet delay jitter, so that it can traffic flow medium data. JFED impose effective punishment upon non-responsible flow with a full stateless method. To verify the performance of JFED, it is implemented in NS2 and is compared with RED and CHOKe with respect to different performance metrics. Simulation results show that the proposed JFED algorithm outperforms RED and CHOKe in stabilizing instantaneous queue length and in fairness. It is also shown that JFED enables the link capacity to be fully utilized by stabilizing the queue length at a desirable level, while not incurring excessive packet loss ratio.

Wang, Xue-Shun; Yu, Shao-Hua; Dai, Jin-You; Luo, Ting

2009-11-01

265

Using Archived AVL/APC Bus Data to Identify Spatial-Temporal1 Causes of Bus Bunching2  

E-print Network

measures and new strategies to improve16 bus operations performance. This study is motivated by the low and operators to measure and visualize transit system performance. Focusing on bus7 bunching, this paper performance of a route operated by17 Portland Tri-County Metropolitan Transportation District of Oregon (Tri

Bertini, Robert L.

266

Bus industry market study. Report -- Task 3.2: Fuel cell/battery powered bus system  

SciTech Connect

In support of the commercialization of fuel cells for transportation, Georgetown University, as a part of the DOE/DOT Fuel Cell Transit Bus Program, conducted a market study to determine the inventory of passenger buses in service as of December, 1991, the number of buses delivered in 1991 and an estimate of the number of buses to be delivered in 1992. Short term and long term market projections of deliveries were also made. Data was collected according to type of bus and the field was divided into the following categories which are defined in the report: transit buses, school buses, commercial non-transit buses, and intercity buses. The findings of this study presented with various tables of data collected from identified sources as well as narrative analysis based upon interviews conducted during the survey.

Zalbowitz, M.

1992-06-02

267

The Wheels on the Bus Go "Buy Buy Buy": School Bus Advertising Laws  

PubMed Central

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

2012-01-01

268

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

PubMed

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

Pomeranz, Jennifer L

2012-09-01

269

Status of the FASTBUS standard data bus  

SciTech Connect

FASTBUS is a new laboratory standard data bus intended for use in experimental data acquisition and control. The development of FASTBUS began with a feasibility study in 1976, and is presently at the development prototyping stage. The principal aims of the standard are to provide a factor of ten or more improvement in speed of data transfers over present systems, as well as to provide an architecture for systems containing multiple processors. Developmental prototypes now in progress include crates, backplanes, cooling devices, power supplies, test and diagnostic modules, and user modules. A sizeable software development effort is also underway. Several experiments have made commitments to use FASTBUS. A review of current work and potential applications is given. 10 figures.

Larsen, R.S.

1980-11-01

270

Telemetry and control baseband bus for the modern spacecraft  

NASA Astrophysics Data System (ADS)

A typical modern spacecraft Telemetry and Control (T&C) subsystem is presented. Subsystem requirements for data rates, responsiveness, reliability, autonomy and fault tolerance are addressed. For the primary T&C data bus, an evaluation is made of two competing time multiplexed communication buses: MIL-STD-1553B and the STACC (Standard Telemetry and Command Components) Multiplex Data Bus (MDB). A review of each bus type is presented describing bus protocol, timing, expansion via remotes, inherent fault tolerance, fault avoidance, and connection medium. Bandwidth (BW) limitations are identified for each bus type and some proposed methods are presented to improve BW efficiency. Improved protocols for data rates in excess of one megabit per second which will be capable of multiplexing voice and image data are also presented. Some design options are also presented for economic and reliable bus to user interfaces. A final data bus configuration is recommended which has adequate BW, flexibility and fault tolerance for the modern spacecraft T&C subsystem.

Rao Gadwal, G.; Capots, L. H.

271

Dual Diagnosis  

Microsoft Academic Search

It is estimated that 10 million persons in me United States have at least one mental disorder and at least one substance-related disorder in any given year. Dual disorders are common in psychiatry, but misdiagnosis may be even more common. Drug and alcohol testing should be expanded from routine use in the Olympics and intercollegiate athletics to psychiatric diagnosis of

Mark S. Gold

2005-01-01

272

Dual diagnosis  

Microsoft Academic Search

Dual diagnosis in psychiatry and addiction refers to the presence of a substance use disorder coexisting with another major psychiatric disorder. This article reviews the prevalence and timing of occurrence of the various disorders and their combinations. The problems in diagnosis and management associated with these diagnoses are explored both from the point of view of the patient and of

Michael Finbar Sheehan; CAROLINE HAWKINGS

1993-01-01

273

Apollo 14 mission: Inability to disconnect main bus A  

NASA Technical Reports Server (NTRS)

During entry, the Apollo 14 spacecraft busses should have de-energized when the main bus-tie motor switches were switched to the off position. One motor switch did not transfer and main bus A remained energized until the battery bus-tie circuit breakers were opened after landing. Analysis revealed that residual catalyst caused the terminal pin seals to revert to a gummy state. Resulting reversion products then migrated to the motor commutator and caused brush degradation, increased and erratic commutator resistance, and reduced motor torque. The motor stalled when available motor torque was reduced below that required to drive through the maximum torque point of the switch.

1971-01-01

274

Classroom Activities in School Bus and Pedestrian Safety Education. Bulletin No. 93138.  

ERIC Educational Resources Information Center

School bus and related pedestrian safety education is prevention-oriented so that students will learn how to avoid bus-related accidents. This manual provides lesson plans emphasizing the school bus stop, loading and unloading zones, emergency evacuation drills, and appropriate behavior on the school bus. The guide also recognizes demographic…

Wisconsin State Dept. of Transportation, Madison.

275

Queueing models of picture archiving and communication systems  

NASA Astrophysics Data System (ADS)

At present the management of radiological information is done manually in most hospitals. Images from the digital modalities (e.g. Computer- tomography scanners, X-ray machines) are converted into films and stored in a room. These films are then distributed manually and interpretation is done by reading the films through light boxes. With the advances in semiconductor technology and digital processing techniques it is now possible to automate these operations by using a digital system for archiving and communication of images. A Picture Archiving and Communication System (PACS), is a digital system for acquiring, storing, moving and displaying picture or image information .These systems are highly dependent on the new technology for mass storage of data on optical disks. In the medical environment, the ultimate goal of using digital images and PACS is tohave a radiology department without filmjackets 2,3 A typical PACS consists of a database of medical images, display stations, acquisition systems and the communications medium. There are two possible architectures for PACS, one is the distributed PACS where all the modules are linked together through a high speed communication medium, and the other is a centralized PACS where the acquisition nodes and the display stations are part of the system which comprises the image database 4. In this paper we present analytical queueing models of distributed PACS used in the medical environments. These models are for the image database, the picture viewing stations, and the communication channels.

Khanmoradi, Hassan; Nilsson, Arne A.

1990-08-01

276

Priority queues with bursty arrivals of incoming tasks  

NASA Astrophysics Data System (ADS)

Recently increased accessibility of large-scale digital records enables one to monitor human activities such as the interevent time distributions between two consecutive visits to a web portal by a single user, two consecutive emails sent out by a user, two consecutive library loans made by a single individual, etc. Interestingly, those distributions exhibit a universal behavior, D(?)˜?-? , where ? is the interevent time, and ??1 or 3/2 . The universal behaviors have been modeled via the waiting-time distribution of a task in the queue operating based on priority; the waiting time follows a power-law distribution Pw(?)˜?-? with either ?=1 or 3/2 depending on the detail of queuing dynamics. In these models, the number of incoming tasks in a unit time interval has been assumed to follow a Poisson-type distribution. For an email system, however, the number of emails delivered to a mail box in a unit time we measured follows a power-law distribution with general exponent ? . For this case, we obtain analytically the exponent ? , which is not necessarily 1 or 3/2 and takes nonuniversal values depending on ? . We develop the generating function formalism to obtain the exponent ? , which is distinct from the continuous time approximation used in the previous studies.

Masuda, N.; Kim, J. S.; Kahng, B.

2009-03-01

277

Probabilistic Analysis of Buffer Starvation in Markovian Queues  

E-print Network

Our purpose in this paper is to obtain the exact distribution of the number of buffer starvations within a sequence of $N$ consecutive packet arrivals. The buffer is modeled as an M/M/1 queue, plus the consideration of bursty arrivals characterized by an interrupted Poisson process. When the buffer is empty, the service restarts after a certain amount of packets are prefetched. With this goal, we propose two approaches, one of which is based on Ballot theorem, and the other uses recursive equations. The Ballot theorem approach gives an explicit solution, but at the cost of the high complexity order in certain circumstances. The recursive approach, though not offering an explicit result, needs fewer computations. We further propose a fluid analysis of starvation probability on the file level, given the distribution of file size and the traffic intensity. The starvation probabilities of this paper have many potential applications. We apply them to optimize the quality of experience (QoE) of media streaming serv...

Xu, Yuedong; El-Azouzi, Rachid; Haddad, Majed; Elayoubi, Salaheddine; Jimenez, Tania

2011-01-01

278

PARENT AND FAMILY RELATIONS BUS TRIP SEAT TRASFER Date:_________________  

E-print Network

PARENT AND FAMILY RELATIONS BUS TRIP SEAT TRASFER Date:_________________ Destination: __ D-way __ Round-trip ORIGINAL PURCHASER INFORMATION: Parent/Guardian name(s): ______________________________________________ Parent/Guardian email: ________________________________________________ Student name

Rock, Chris

279

Sustainable transport at MIT : improving area bus services  

E-print Network

Everyday each member of the MIT community makes a decision about how they will travel to school or work. Using the Commuter Habit Survey and information regarding local bus services as guides, this report analyzes the ...

Beasley, Aimee K

2009-01-01

280

Bus use behavior in multi-route corridors  

E-print Network

Multi-route corridors are a common feature of bus networks. In these corridors, passengers select between a set of parallel routes. Understanding how passengers make these decisions can help better measure passenger ...

Viggiano, Cecilia A. (Cecilia Ann)

2013-01-01

281

Performance-optimized optical bidirectional backplane bus for multiprocessor systems  

NASA Astrophysics Data System (ADS)

We review the recent results on the design and implementation of the performance-optimized bidirectional optical backplane bus aimed at high speed multiprocessor systems. It employs an array of multiplexed holograms, in conjunction with a waveguiding plate within which cascaded fanouts are generated. Data transfer rate of 1.2 Gbit/sec at 1300 nm is demonstrated with a single bus line for a system composed of nine boards. Packaging-related issues and misalignment effects are addressed. Theoretical treatment to minimize fluctuations among the received powers at each board was carried out and the overall performance was optimized. We also introduce a hybrid optical backplane with multiple bus lines. The hybrid backplane maintains the same waveguiding structure, and exploits optoelectronic array devices. A new demonstration system is being implemented. The optical backplane that we developed is transparent to higher level bus protocols, thus can support standard backplane buses such as Futurebus+, Multibus II, and VMEbus.

Chen, Ray T.; Zhao, Chunhe; Oh, Tchang-Hun

1996-01-01

282

Analysis of feeder bus network design and scheduling problems.  

PubMed

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

Almasi, Mohammad Hadi; Mirzapour Mounes, Sina; Koting, Suhana; Karim, Mohamed Rehan

2014-01-01

283

Analysis of Feeder Bus Network Design and Scheduling Problems  

PubMed Central

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

Almasi, Mohammad Hadi; Karim, Mohamed Rehan

2014-01-01

284

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

285

The threat of punishment enforces peaceful cooperation and stabilizes queues in a coral-reef fish.  

PubMed

Social queues, in which subordinates wait for their turn to inherit dominant breeding status, are a familiar feature of many animal societies. However, little is known about the mechanisms stabilizing social queues given the inevitable conflict over rank between group members. Here, we report the role of punishment and cooperation in promoting the stability of size-based queues in a coral-dwelling goby, Paragobiodon xanthosomus (Gobiidae). Quantitative analysis of the size-structure of queues revealed that individuals of adjacent rank differ in size by a specific size ratio, and comparisons of individual growth rates within queues demonstrated that specific size ratios are maintained over time via the regulation of subordinate growth rates. Furthermore, contest experiments demonstrated that the specific size ratio represents a threshold above which the subordinates become a threat to their immediate dominant, and as a result, dominants evict subordinates that exceed this size ratio from the group. We propose that threshold size ratios are maintained by subordinates as a form of peaceful cooperation whereby they avoid inflicting costs on dominants, and that such cooperation arises in response to the threat of punishment in the form of eviction by dominants. Societal stability is therefore achieved through the effects of punishment and cooperation acting in concert to promote the resolution of conflict over rank between group members. PMID:17301018

Wong, Marian Y L; Buston, Peter M; Munday, Philip L; Jones, Geoffrey P

2007-04-22

286

DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

SciTech Connect

The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethylether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The bulk of the efforts over the past year were focused on the conversion of the campus shuttle bus. This process, started in August 2001, took until April 2002 to complete. The process culminated in an event to celebrate the launching of the shuttle bus on DME-diesel operation on April 19, 2002. The design of the system on the shuttle bus was patterned after the system developed in the engine laboratory, but also was subjected to a rigorous failure modes effects analysis with help from Dr. James Hansel of Air Products. The result of this FMEA was the addition of layers of redundancy and over-pressure protection to the system on the shuttle bus. The system became operation in February 2002. Preliminary emissions tests and basic operation of the shuttle bus took place at the Pennsylvania Transportation institute's test track facility near the University Park airport. After modification and optimization of the system on the bus, operation on the campus shuttle route began in early June 2002. However, the work and challenges have continued as it has been difficult to maintain operability of the shuttle bus due to fuel and component difficulties. As of late June 2002, it appears that the pump head itself developed operational problems (loss of smooth function) leading to excessive stress on the magnetic coupling and excessive current draw to operate. A new pump head is being installed on the system to alleviate this problem and get the shuttle bus back in operation. In summary, the conversion is completed but there have been operational challenges in the field. They continue to work to make the shuttle bus as reliable to operate on DME-diesel blends as possible.

Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

2003-04-01

287

Hardware Design of Automobile Door with Local Interconnect Network Bus  

Microsoft Academic Search

In this paper, we presented a hardware design example of automobile door with local interconnect network (LIN) bus. The LIN bus based automobile door has follow functions: manual or auto lift and auto lift out the car, auto anti-pinch, enable\\/disable the lift motor, central controlled door lock, door-controlled top lamp of cockpit, auto unlocking and locking, and so on. In

Zhaoxia Xiao; Youcheng Li

2011-01-01

288

Final Report for the H2Fuel Bus  

SciTech Connect

The H2Fuel Bus is the world's first hydrogen-fueled electric hybrid transit bus. It was a project developed through a public/private partnership involving several leading technological and industrial organizations, with primary funding by the Department of Energy (DOE). The primary goals of the project are to gain valuable information on the technical readiness and economic viability of hydrogen fueled buses and to enhance the public awareness and acceptance of emerging hydrogen technologies.

Jacobs, W.D.

1998-11-25

289

Solving bus terminal location problems using evolutionary algorithms  

Microsoft Academic Search

Bus terminal assignment with the objective of maximizing public transportation service is known as bus terminal location problem (BTLP). We formulate the BTLP, a problem of concern in transportation industry, as a p-uncapacitated facility location problem (p-UFLP) with distance constraint. The p-UFLP being NP-hard (Krarup and Pruzan, 1990), we propose evolutionary algorithms for its solution. According to the No Free

Reza Ghanbari; Nezam Mahdavi-Amiri

2011-01-01

290

Bus interdiction efforts by the police: United States v. Drayton  

Microsoft Academic Search

The Supreme Court recently addressed the constitutionality of police interdiction efforts when conducting bus sweeps. The\\u000a Court held that law enforcement officers are not required by the Fourth Amendment to “advise bus passengers of their right\\u000a not to cooperate and to refuse consent to searches” (U.S. v. Drayton, 2002, p. 2107). The decision may have implications for\\u000a how the judicial

THOMAS W. HUGHESt

2003-01-01

291

Compressed natural gas bus safety: a quantitative risk assessment.  

PubMed

This study assesses the fire safety risks associated with compressed natural gas (CNG) vehicle systems, comprising primarily a typical school bus and supporting fuel infrastructure. The study determines the sensitivity of the results to variations in component failure rates and consequences of fire events. The components and subsystems that contribute most to fire safety risk are determined. Finally, the results are compared to fire risks of the present generation of diesel-fueled school buses. Direct computation of the safety risks associated with diesel-powered vehicles is possible because these are mature technologies for which historical performance data are available. Because of limited experience, fatal accident data for CNG bus fleets are minimal. Therefore, this study uses the probabilistic risk assessment (PRA) approach to model and predict fire safety risk of CNG buses. Generic failure data, engineering judgments, and assumptions are used in this study. This study predicts the mean fire fatality risk for typical CNG buses as approximately 0.23 fatalities per 100-million miles for all people involved, including bus passengers. The study estimates mean values of 0.16 fatalities per 100-million miles for bus passengers only. Based on historical data, diesel school bus mean fire fatality risk is 0.091 and 0.0007 per 100-million miles for all people and bus passengers, respectively. One can therefore conclude that CNG buses are more prone to fire fatality risk by 2.5 times that of diesel buses, with the bus passengers being more at risk by over two orders of magnitude. The study estimates a mean fire risk frequency of 2.2 x 10(-5) fatalities/bus per year. The 5% and 95% uncertainty bounds are 9.1 x 10(-6) and 4.0 x 10(-5), respectively. The risk result was found to be affected most by failure rates of pressure relief valves, CNG cylinders, and fuel piping. PMID:15876211

Chamberlain, Samuel; Modarres, Mohammad

2005-04-01

292

DIMETHYL ETHER (DME)FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

Microsoft Academic Search

The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it

Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

2003-01-01

293

Scheme for Measuring Queueing Delay of a Router using Probe-Gap Model: The Single-Hop Case  

E-print Network

Scheme for Measuring Queueing Delay of a Router using Probe-Gap Model: The Single-Hop Case to measure queueing delay of a router in a single-hop path. The proposed scheme is based on estimating the change of an intra- probe gap between a pair of probing packets after they traverse the router under test

Rojas-Cessa, Roberto

294

Optimal buffer size and dynamic rate control for a queueing network with impatient customers in heavy traffic.  

E-print Network

Optimal buffer size and dynamic rate control for a queueing network with impatient customers abandonment in heavy traffic. The controller can choose a buffer size for the queuing network and also can an asymptotically optimal control policy, i.e. an optimal buffer size and an optimal service rate for the queueing

Ghosh, Arka P.

295

Buffer Allocation in General Single-Server Queueing2 F. R. B. Cruz a,, A. R. Duarte a  

E-print Network

1 Buffer Allocation in General Single-Server Queueing2 Networks3 F. R. B. Cruz a,, A. R. Duarte of Technology, Eindhoven, The6 Netherlands7 Abstract8 The optimal buffer allocation in queueing network systems harder. A good approximation for the performance measures is thus essential for11 a successful buffer

Cruz, Frederico

296

Strategies for a Centralized Single Product Multi-Class M/G/1 Make-to-Stock Queue  

E-print Network

Strategies for a Centralized Single Product Multi-Class M/G/1 Make-to-Stock Queue Hossein Abouee, ON M5S 3G8, CANADA, baris@mie.utoronto.ca Abstract Make-to-stock queues are typically investigated and SP policies. Dynamic programming, the common tool used in investigating the IR policy in make-to-stock

Balcioglu, Baris

297

STOCK RATIONING IN A MULTI-CLASS MAKE-TO-STOCK QUEUE WITH INFORMATION ON THE PRODUCTION STATUS  

E-print Network

STOCK RATIONING IN A MULTI-CLASS MAKE-TO-STOCK QUEUE WITH INFORMATION ON THE PRODUCTION STATUS Engineering Ko¸c University 34450, Sariyer, Istanbul, TURKEY fkaraesmen@ku.edu.tr #12;Stock Rationing in a Multi-class Make-to-Stock Queue with Information on the Production Status August 17, 2006 Abstract We

Karaesmen, Fikri

298

A Paradox in Optimal Flow Control of M/M/m Queues Atsushi Inoie, Hisao Kameda and Corinne Touati  

E-print Network

Abstract-- Optimal flow control problems of multiple-server (M/M/m) queueing systems are studied. Due systems into one system provides improved performance over the previously separated systems. This paper/M/m queueing systems where each player strives to optimize uni- laterally its own power where the power

Touati, Corinne

299

The abstract Cauchy problem for the non-stationary bulk queue M(t)|M[k, B]|1  

E-print Network

We derived state probability equations describing the queue M(t)|M[k, B]|1 and formulated as an abstract Cauchy problem to investigate by means of the semi-group theory of bounded linear operators in functional analysis. For the abstract Cauchy problem of this queue, we determined the eigenfunctions of maximal operator and showed some properties of the Dirichlet operator.

Yong Chol Chon

2013-11-05

300

DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

SciTech Connect

The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Their strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The bulk of the efforts over the past year were focused on the conversion of the campus shuttle bus. This process, started in August 2001, took until April 2002 to complete. The process culminated in an event to celebrate the launching of the shuttle bus on DME-diesel operation on April 19, 2002. The design of the system on the shuttle bus was patterned after the system developed in the engine laboratory, but also was subjected to a rigorous failure modes effects analysis (FMEA, referred to by Air Products as a ''HAZOP'' analysis) with help from Dr. James Hansel of Air Products. The result of this FMEA was the addition of layers of redundancy and over-pressure protection to the system on the shuttle bus. The system became operational in February 2002. Preliminary emissions tests and basic operation of the shuttle bus took place at the Pennsylvania Transportation Institute's test track facility near the University Park airport. After modification and optimization of the system on the bus, operation on the campus shuttle route began in early June 2002. However, the work and challenges continued as it has been difficult to maintain operability of the shuttle bus due to fuel and component difficulties. In late June 2002, the pump head itself developed operational problems (loss of smooth function) leading to excessive stress on the magnetic coupling and excessive current draw to operate. A new pump head was installed on the system to alleviate this problem and the shuttle bus operated successfully on DME blends from 10-25 vol% on the shuttle bus loop until September 30, 2002. During the period of operation on the campus loop, the bus was pulled from service, operated at the PTI test track and real-time emissions measurements were obtained using an on-board emissions analyzer from Clean Air Technologies International, Inc. Particulate emissions reductions of 60% and 80% were observed at DME blend ratios of 12 vol.% and 25 vol.%, respectively, as the bus was operated over the Orange County driving cycle. Increases in NOx, CO and HC emissions were observed, however. In summary, the conversion of the shuttle bus was successfully accomplished, particulate emissions reductions were observed, but there were operational challenges in the field. Nonetheless, they were able to demonstrate reliable operation of the shuttle bus on DME-diesel blends.

Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

2003-04-01

301

Stochastic ordering properties and optimal routing control for a class of finite capacity queueing systems  

NASA Technical Reports Server (NTRS)

The problem of routing jobs to parallel queues with identical exponential servers and unequal finite buffer capacities is considered. Stochastic ordering and weak majorization properties on critical performance measures are established by means of event-driven inductions. In particular, it is shown that the intuitive 'join the shortest non-full queue' (SNQ) policy is optimal with respect to an overall function that accounts for holding and blocking costs. Moreover, the buffer allocation problem is solved by proving the intuitive result that, for a fixed total buffer capacity, the optimal allocation scheme is the one in which the difference between the maximum and minimum queue capacities is minimized, i.e., becomes either 0 or 1.

Towsley, Don; Sparaggis, Panayotis D.; Cassandras, Christos G.

1990-01-01

302

Design and analysis of a model predictive controller for active queue management.  

PubMed

Model predictive (MP) control as a novel active queue management (AQM) algorithm in dynamic computer networks is proposed. According to the predicted future queue length in the data buffer, early packets at the router are dropped reasonably by the MPAQM controller so that the queue length reaches the desired value with minimal tracking error. The drop probability is obtained by optimizing the network performance. Further, randomized algorithms are applied to analyze the robustness of MPAQM successfully, and also to provide the stability domain of systems with uncertain network parameters. The performances of MPAQM are evaluated through a series of simulations in NS2. The simulation results show that the MPAQM algorithm outperforms RED, PI, and REM algorithms in terms of stability, disturbance rejection, and robustness. PMID:21963108

Wang, Ping; Chen, Hong; Yang, Xiaoping; Ma, Yan

2012-01-01

303

The M/G/1 retrial queue: New descriptors of the customer's behavior  

NASA Astrophysics Data System (ADS)

We consider queuing systems where customers are not allowed to queue; instead of that they make repeated attempts, or retrials, in order to enter service after some time. The performance of telephone systems and communication networks modelled as retrial queues differs from standard waiting lines because typically the retrial group is an invisible queue which cannot be observed. As a result, the original flow of primary arrivals and the flow of repeated attempts become undistinguished. Our aim in this paper is to consider some aspects of this problem. Thus, we focus on the main retrial model of M/G/1 type and investigate the distribution of the successful and blocked events made by the primary customers and the retrial customers.

Amador, J.; Artalejo, J. R.

2009-01-01

304

A GA-based PID active queue management control design for TCP/IP networks  

NASA Astrophysics Data System (ADS)

In this paper, a genetic algorithm-based (GA-based) proportional-integral-derivative (PID) controller as an active queue manager for Internet routers is proposed to reduce packet loss and improve network utilization in TCP/IP networks. Based on the window-based nonlinear dynamics, the TCP network was modeled as a time-delayed system with a saturated input due to the limitations of packet-dropping probability and the effects of propagation delays in TCP networks. An improved genetic algorithm is employed to derive optimal or near optimal PID control gains such that a performance index of integrated-absolute error (IAE) in terms of the error between the router queue length and the desired queue length is minimized. The performance of the proposed control scheme was evaluated in various network scenarios via a series of numerical simulations. The simulation results confirm that the proposed scheme outperforms other AQM schemes.

Kuo, H.-H.; Chen, C.-K.; Yan, J.-J.; Liao, T.-L.

2008-02-01

305

A Cost Benefit Analysis of a V2G-Capable Electric School Bus Compared to a Traditional Diesel School Bus  

E-print Network

A Cost Benefit Analysis of a V2G-Capable Electric School Bus Compared to a Traditional Diesel analysis of a V2G-capable electric school bus compared to a traditional diesel school bus. Applied Energy 19716 Abstract Fuel expenses, diesel exhaust health externalities, and climate change are concerns

Firestone, Jeremy

306

Modelling and Analysis of Priority Queueing Systems with Multi-Class Self-Similar Network Traffic: A Novel and Efficient Queue-Decomposition Approach  

Microsoft Academic Search

Traffic self-similarity has been discovered to be a ubiquitous phenomenon in communication networks and multimedia systems. Due to its fractal-like nature, performance modelling of self-similar traffic poses greater challenges and exhibits more complexity than that of traditional non-bursty traffic. As a result, most existing studies on analytical modelling of priority queueing systems with self-similar inputs have been restricted to a

Xiaolong Jin; Geyong Min

2009-01-01

307

Effect of bus size and operation to crash occurrences.  

PubMed

This paper evaluates roadway and operational factors considered to influence crashes involving buses. Factors evaluated included those related to bus sizes and operation services. Negative binomial (NB) and multinomial logit (MNL) models were used in linearizing and quantifying these factors with respect to crash frequency and injury severities, respectively. The results showed that position of the bus travel lane, presence or absence of on-street shoulder parking, posted speed limit, lane width, median width, number of lanes per direction and number of vehicles per lane has a higher influence on bus crashes compared to other roadway and traffic factors. Wider lanes and medians were found to reduce probability of bus crashes while more lanes and higher volume per lane were found to increase the likelihood of occurrences of bus-related crashes. Roadways with higher posted speed limits excluding freeways were found to have high probability of crashes compared to low speed limit roadways. Buses traveling on the inner lanes and making left turns were found to have higher probability of crashes compared to those traveling on the right most lanes. The same factors were found to influence injury severity though with varying magnitudes compared to crash frequency. PMID:20728663

Chimba, Deo; Sando, Thobias; Kwigizile, Valerian

2010-11-01

308

Queueing Syst DOI 10.1007/s11134-008-9084-7  

E-print Network

-sided exit problem for a difference of a com- pound Poisson process and a compound renewal process. More of the compound Poisson process and the re- newal process whose jumps are exponentially distributed. The advantageQueueing Syst DOI 10.1007/s11134-008-9084-7 Exit problems for the difference of a compound Poisson

Einmahl, Uwe

309

HITTING AND RUIN PROBABILITIES FOR COMPOUND POISSON PROCESSES AND THE CYCLE MAXIMUM OF THE 1 QUEUE  

Microsoft Academic Search

We derive a new formula for the probability that a compound Poisson process with positive jumps hits a lower straight line before it crosses a parallel upper line. This yields a new approach to determine the distribution of the cycle maximum of the queue. Moreover, we express the hitting probabilities in terms of the corresponding ruin probabilities.

D. Perry; W. Stadje; S. Zacks

2002-01-01

310

Shared Receive Queue based Scalable MPI Design for InfiniBand Clusters  

E-print Network

Receive Queue (SRQ) · SRQ is a hardware mechanism in InfiniBand by which a process can share receiveMPI Process Without SRQ MPI ProcessMPI Process With SRQ New question: How can senders estimate in seconds #12;Proposed MPI Design with SRQ Buffer PoolBuffer Pool Buffer PoolBuffer Pool Send/Receive RDMA

Panda, Dhabaleswar K.

311

ANALYSIS OF THE M=M=1 QUEUE WITH PROCESSOR SHARING VIA SPECTRAL THEORY  

E-print Network

analysis, which led to an integral representation of the survivor probability distribution function that the computation of the sojourn time distribution can be formulated as a spectral problem for a selfANALYSIS OF THE M=M=1 QUEUE WITH PROCESSOR SHARING VIA SPECTRAL THEORY FABRICE GUILLEMIN

Guillemin, Fabrice

312

Queueing Analysis of Polling Based Wireless MAC Protocols with Sleep-Wake Cycles  

E-print Network

1 Queueing Analysis of Polling Based Wireless MAC Protocols with Sleep-Wake Cycles Haiming Yang in ongoing transmissions. Decentralized contention based MAC protocols that use different variants of sleep-wake cycles have been studied extensively in literature [2], [3], [4]. The performance of these decentralized

Sikdar, Biplab

313

A standard interface for debugger access to message queue information in MPI.  

SciTech Connect

This paper discusses the design and implementation of an interface that allows a debugger to obtain the information necessary to display the contents of the MPI message queues. The design has been implemented in the TotalView debugger, and dynamic libraries that conform to the interface exist for MPICH, as well as the proprietary MPI implementations from Compaq, IBM, and SGI.

Cownie, J.; Gropp. W.

1999-06-25

314

A Queueing Network Analysis of Computer Communication Networks with Window Flow Control  

Microsoft Academic Search

A computer communication network with window flow control is modeled by a closed multichain queueing network. The severe computational limitation of previous solution algorithms is overcome with a heuristic derived from the recently found mean value analysis. A large numerical example is given.

MARTIN REISER

1979-01-01

315

Attendre: Mitigating Ill Effects of Race Conditions in OpenFlow via Queueing Mechanism  

E-print Network

processes them in reverse. The Type 3 race (not depicted due to space limit) is ex- perienced by the networkAttendre: Mitigating Ill Effects of Race Conditions in OpenFlow via Queueing Mechanism Xiaoye Sun, a packet-in message is sent to the controller. This be- haviour results in various types of race conditions

Ng, T. S. Eugene

316

A Collaborative Approach to Stochastic Load Balancing with Networked Queues of Autonomous Service Clusters  

Microsoft Academic Search

Load balancing has been an increasingly important issue for handling computational intensive tasks in a distributed system such as in grid and cluster computing. In such systems, multiple server instances are installed for handling requests from client applications, and each request (or task) typically needs to stay in a queue before an available server is assigned to process it. In

Cheng-Jia Lai; Wolfgang Polak

2006-01-01

317

A Factor Graph Modelling of Product-Form Loss and Queueing Networks  

E-print Network

A Factor Graph Modelling of Product-Form Loss and Queueing Networks Jian Ni and Sekhar Tatikonda of product-form stochastic networks. Based on the factor graph model one can easily derive recursive formulas graphical models to analyze product-form stochastic networks. Specifically, we propose to use factor graphs

Tatikonda, Sekhar

318

On the integral of the workload process of the single server queue  

E-print Network

. Secondly, we consider the problem of obtaining an explicit expression for the distribution of A. In the general GI|G|1 case, we use a sequential approximation to find the Laplace-Stieltjes transform of A consider moments of A in the GI|G|1 queue. Finally, we show asymptotic normality of t 0 W(s) ds. Keywords

Palmowski, Zbigniew

319

An M/M/1 queue in a semiMarkovian environment Philippe Nain Rudesindo N  

E-print Network

of Riemann-Hilbert boundary value problems we compute the z-transform of the queue-length distribution when either F0 (x) or F1 (x) has a rational Laplace-Stieltjes transform and the other may be a general-Hilbert boundary value problem; Long-range dependence; Bursty traÃ?c. Categories and Subject Descriptors C4

Núñez-Queija, Rudesindo

320

Stock Rationing in an M/Ek/1 Make-to-Stock Queue with Backorders  

E-print Network

Stock Rationing in an M/Ek/1 Make-to-Stock Queue with Backorders J.P. Gayon · Francis de V.duke.edu · fkaraesmen@ku.edu.tr We consider a single-item make-to-stock production system. The item is demanded status in a tractable way. We show different properties of the optimal stock allocation policy

Karaesmen, Fikri

321

Performance Evaluation 40 (2000) 2746 A novel approach to queue stability analysis of polling models  

E-print Network

in modeling many real-world systems. For example, token-passing LAN, polling scheme, and processor sharing on stability of the whole system. This system stability analysis, however, fails to model many real-world systems for which some queues may continue to operate under an unstable system. In this paper we address

Chang, Rocky Kow-Chuen

322

A high throughput packet-switching network with neural network controlled bypass queueing and multiplexing  

SciTech Connect

This paper proposes a high throughput packet switching network with bypass queues based on a MIN. We improve the switch throughput by partitioning the input buffers into disjoint buffer sets and multiplexing several sets of nonblocking packets within a time slot. A neural network model is presented as a controller for packet scheduling and multiplexing in the switch.

Park, Y.K.; Lee, G. [Univ. of Minnesota, Minneapolis, MN (United States)

1994-12-31

323

A systems analysis and model of a parallel multi-server queueing system  

Microsoft Academic Search

A feasible set of management policies to handle multitandem queueing systems characterized by stochastic demand is presented in this paper. This type of system is common in many service related organizations. The research employs a previously developed simulation model of a State of Florida driver licensing office to manipulate policy variables in an effort to provide options for increased system

Thomas D. Clark Jr.; Donald H. Hammond; Kathy L. McCommon

1990-01-01

324

Packet Fair Queueing Algorithms for Wireless Networks with Location-Dependent Errors  

Microsoft Academic Search

While Packet Fair Queueing (PFQ) algorithms provide both bounded delay and fairness in wired networks, they cannot be applied di- rectly to wireless networks. The key difficulty is that in wireless networks sessions can experience location-dependent channel errors . This may lead to situations in which a session receives significantly less service than it is supposed to, while another receives

T. S. Eugene Ng; Ion Stoica; Hui Zhang

1998-01-01

325

Stability properties of constrained queueing systems and scheduling policies for maximum throughput in multihop radio networks  

Microsoft Academic Search

The stability of a queueing network with interdependent servers is considered. The dependency among the servers is described by the definition of their subsets that can be activated simultaneously. Multihop radio networks provide a motivation for the consideration of this system. The problem of scheduling the server activation under the constraints imposed by the dependency among servers is studied. The

Leandros Tassiulas; Anthony Ephremides

1992-01-01

326

Queueing Behavior of Hashing Methods Used to Build URL Routing Tables  

E-print Network

Queueing Behavior of Hashing Methods Used to Build URL Routing Tables Zornitza Genova Prodanoff behavior. We examine hashing as applied to URL routing used in Content Distribution Networks (CDNs). URL can be very insightful. Fig. 1 URL router forwarding or redirecting a request I. INTRODUCTION Content

Prodanoff, Zornitza Genova

327

To appear in ACM Queue, 2006 Situation Models for Observing Human Activity  

E-print Network

To appear in ACM Queue, 2006 Situation Models for Observing Human Activity James L. Crowley are described as scenarios composed of actors and objects within a network of situations. We provide formal definitions for the underlying concepts for situation models, and then propose a layered, component

Crowley, James L.

328

Individual, Class-based, and Social Optimal Admission Policies in Two-Priority Queues  

E-print Network

Individual, Class-based, and Social Optimal Admission Policies in Two-Priority Queues Feng Chen class 2 customers than the socially optimal policy, which has interesting socio-economic explanation classes of customers. Class 1 customers have preemptive resume priority over class 2 customers. Within

Kulkarni, Vidyadhar G.

329

Queueing Syst DOI 10.1007/s11134-009-9109-x  

E-print Network

, and the effect of system parameters on the structured optimal policy is analyzed for each individual operatorQueueing Syst DOI 10.1007/s11134-009-9109-x Effects of system parameters on the optimal policy Received: 18 August 2008 / Revised: 29 January 2009 © Springer Science+Business Media, LLC 2009 Abstract

Karaesmen, Fikri

330

Fokker-Planck description for the queue dynamics of large tick stocks.  

PubMed

Motivated by empirical data, we develop a statistical description of the queue dynamics for large tick assets based on a two-dimensional Fokker-Planck (diffusion) equation. Our description explicitly includes state dependence, i.e., the fact that the drift and diffusion depend on the volume present on both sides of the spread. "Jump" events, corresponding to sudden changes of the best limit price, must also be included as birth-death terms in the Fokker-Planck equation. All quantities involved in the equation can be calibrated using high-frequency data on the best quotes. One of our central findings is that the dynamical process is approximately scale invariant, i.e., the only relevant variable is the ratio of the current volume in the queue to its average value. While the latter shows intraday seasonalities and strong variability across stocks and time periods, the dynamics of the rescaled volumes is universal. In terms of rescaled volumes, we found that the drift has a complex two-dimensional structure, which is a sum of a gradient contribution and a rotational contribution, both stable across stocks and time. This drift term is entirely responsible for the dynamical correlations between the ask queue and the bid queue. PMID:24125314

Garèche, A; Disdier, G; Kockelkoren, J; Bouchaud, J-P

2013-09-01

331

Self-organization of critical behavior in controlled general queueing models  

NASA Astrophysics Data System (ADS)

We consider general queueing models of the (G/G/1) type with service times controlled by the busy period. For feedback control mechanisms driving the system to very high traffic load, it is shown the busy period probability density exhibits a generic - {3}/{2} power law which is a typical mean field behavior of SOC models.

Blanchard, Ph.; Hongler, M.-O.

2004-03-01

332

A differentiable dynamic network loading model that yields queue length distributions and accounts for spillback  

E-print Network

A differentiable dynamic network loading model that yields queue length distributions and accounts for spillback Carolina Osorio Gunnar Fl¨otter¨od Michel Bierlaire Abstract We derive a dynamic network, and dissipation. 1 Introduction The dynamic network loading (DNL) problem is to describe the time- and congestion

Bierlaire, Michel

333

HEAVY TRAFFIC APPROXIMATIONS OF BIRTH AND DEATH PROCESSES WITH SOME QUEUEING APPLICATIONS  

E-print Network

HEAVY TRAFFIC APPROXIMATIONS OF BIRTH AND DEATH PROCESSES WITH SOME QUEUEING APPLICATIONS JEAN-BERNARD GRAVEREAUX, FABRICE GUILLEMIN, AND ERIC THIBAULT Abstract. In this paper, we extend to general birth an death processes the concept of local time introduced in classic work by Stone. We show convergence results

Guillemin, Fabrice

334

HEAVY TRAFFIC APPROXIMATIONS OF BIRTH AND DEATH PROCESSES WITH SOME QUEUEING APPLICATIONS  

E-print Network

HEAVY TRAFFIC APPROXIMATIONS OF BIRTH AND DEATH PROCESSES WITH SOME QUEUEING APPLICATIONS JEAN­BERNARD GRAVEREAUX, FABRICE GUILLEMIN, AND ERIC THIBAULT Abstract. In this paper, we extend to general birth an death processes the concept of local time introduced in classic work by Stone. We show convergence results

Guillemin, Fabrice

335

A SPATIAL MARKOV QUEUEING PROCESS AND ITS APPLI-CATIONS TO WIRELESS LOSS SYSTEMS  

E-print Network

work in [13] by allowing particle mobility. Such spatial birth-mobility-and-death processes can also be seen as a general- ization of the spatial birth-and-death generator, which allows for mobility: spatial birth-and-death process, spatial queueing network, mobility, regularity, ergodicity, invariant

Boyer, Edmond

336

Making Work Queue Cluster-Friendly for Data Intensive Scientific Applications  

E-print Network

is often "unfriendly" to the individual clusters providing service. Each worker manages a single core, requiring intervention by local administrators. In this paper, we describe our modifications that make Work Queue more cluster-friendly for data intensive applications This involves adding two new components

Thain, Douglas

337

A Variable Structure Control Approach to Active Queue Management for TCP with ECN  

E-print Network

- tion. Keywords-- Variable Structure Control, TCP/IP, ECN, AQM, Robustness. I. Introduction TRAFFIC on TCP enhancement. Recently, for the purpose of alleviating congestion problem for IP networks1 A Variable Structure Control Approach to Active Queue Management for TCP with ECN Peng Yan, Yuan

Gao, Yuan

338

Applying queueing theory to improve the modeling of spares provisioning of small combat aircraft units  

Microsoft Academic Search

In Operation Desert Storm, aircraft were organized in small units. These units shared spares internally and operated aircraft with redundant systems. In this paper we compare three quick response approaches based on queueing theory to model and assess the combat effectiveness of spares provisioning decisions for such units.

Theodore P. Lewis; Jeffery K. Cochran

1995-01-01

339

Active Queue Management Controller using Smith Predictor for Time Delay Networks  

Microsoft Academic Search

This paper presents an investigation into a robust controller for active queue management (AQM) using Smith predictor (SP). A new SP random early detector (RED) controller is proposed and compared with traditional RED based controller. It is worth noting that the RED controller is augmented by a Smith predictor structure for plants with medium and high time delays. The proposed

Rafe Khalaf Alasem; M. Alamgir Hossain; Irfan-ullah Awan

2007-01-01

340

Classes, Priorities and Fairness in Queueing Systems School of Computer Science  

E-print Network

Classes, Priorities and Fairness in Queueing Systems David Raz School of Computer Science Tel Brunswick, NJ, USA aviitzha@rutcor.rutgers.edu Hanoch Levy School of Computer Science Tel-Aviv University, the fairness aspects, which are inherent to any preferential system and highly important to customers, have

Levy, Hanoch

341

Male spotted hyenas (Crocuta crocuta) queue for status in social groups dominated by females  

Microsoft Academic Search

A long-term study of immigrant male spotted hyenas (Crocuta crocuta) living in large multimale\\/multifemale groups (clans) demonstrated that males acquire social status by queuing. Maximum likelihood estimates of parameters of a stochastic queuing model that assessed queuing discipline confirmed that immigrant males respected the convention that their positions in a queue of typically 15 or more individuals was determined by

Marion L. East; Heribert Hofer

342

Development of a dual-field heteropoplar power converter  

NASA Technical Reports Server (NTRS)

The design and testing of a 400 watt, dual phase, dual rotor, field modulated inductor alternator is described. The system is designed for use as a flywheel to ac utility line or flywheel to dc bus (electric vehicle) power converter. The machine is unique in that it uses dual rotors and separately controlled fields to produce output current and voltage which are in phase with each other. Having the voltage and current in phase allows the power electronics to be made of simple low cost components. Based on analytical predictions and experimental results, development of a complete 22 kilowatt (30 Hp) power conversion system is recommended. This system would include power electronics and controls and would replace the inductor alternator with an improved electromagnetic conversion system.

Eisenhaure, D. B.; Johnson, B.; Bliamptis, T.; St. George, E.

1981-01-01

343

76 FR 42730 - In the Matter of Certain Univeral Serial Bus (“USB”) Portable Storage Devices, Including USB...  

Federal Register 2010, 2011, 2012, 2013

...Univeral Serial Bus (``USB'') Portable Storage Devices, Including USB Flash Drives and...universal serial bus (``USB'') portable storage devices, including USB flash drives and...universal serial bus (``USB'') portable storage devices, including USB flash drives...

2011-07-19

344

Fuzzy logic control for active bus suspension system  

NASA Astrophysics Data System (ADS)

In this study an active controller is presented for vibration suppression of a full-bus suspension model that use air spring. Since the air spring on the full-bus model may face different working conditions, auxiliary chambers have been designed. The vibrations, caused by the irregularities of the road surfaces, are tried to be suppressed via a multi input-single output fuzzy logic controller. The effect of changes in the number of auxiliary chambers on the vehicle vibrations is also investigated. The numerical results demonstrate that the presented fuzzy logic controller improves both ride comfort and road holding.

Turkkan, Mujde; Yagiz, Nurkan

2013-02-01

345

Quantum bus of metal nanoring with surface plasmon polaritons  

SciTech Connect

We develop an architecture for distributed quantum computation using quantum bus of plasmonic circuits and spin qubits in self-assembled quantum dots. Deterministic quantum gates between two distant spin qubits can be reached by using an adiabatic approach in which quantum dots couple with highly detuned plasmon modes in a metallic nanoring. Plasmonic quantum bus offers a robust and scalable platform for quantum optics experiments and the development of on-chip quantum networks composed of various quantum nodes, such as quantum dots, molecules, and nanoparticles.

Lin Zhirong; Guo Guoping; Tu Tao; Li Haiou; Zou Changling; Ren Xifeng; Guo Guangcan [Key Laboratory of Quantum Information, Chinese Academy of Sciences, University of Science and Technology of China, Hefei 230026 (China); Chen Junxue; Lu Yonghua [Department of Physics, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei 230026 (China)

2010-12-15

346

A bus controller for MIL-1553B and Multibus II  

NASA Astrophysics Data System (ADS)

A two-level distributed computer system has been chosen for the control system for the Heavy Ion Storage Ring K4-K10 [1]. The lower level is being developed in accordance with industrial system standards and it is linked to the upper level by means of the multidrop communication field bus MIL-1553B [3]. MIL-1553B bus controllers (BC) are located in the upper level of the control system, in the crates built to the IEEE1296 (Multibus II) standard.

Kotov, V.; Dubovik, L.; Rybaltchenko, K.

1994-12-01

347

Dynamic behavior in two-route bus traffic system with real-time information  

NASA Astrophysics Data System (ADS)

We study the dynamics of two-route bus traffic system with two buses using a bus choice scenario. The two-route bus traffic system with real-time information is not consistent with the two-route vehicular traffic system but is similar to the vehicular system. The two-route bus traffic system is mimicked by the physically dynamic model. The dynamics of two-route bus traffic system is described by a couple of nonlinear maps. A bus runs a neck- and neck race with another bus. The motion of two buses displays an irregular behavior in a complex manner. We clarify the effect of real-time information on the bus traffic.

Nagatani, Takashi

2014-11-01

348

A methodology for identifying potential locations for bus priority treatments in the London Network  

E-print Network

Bus priority strategies provide preferential treatment to buses operating in mixed traffic. This thesis aims at developing a methodology for identifying locations for potential bus priority implementation, referred to as ...

Machlab, Farah J. (Farah Jacinthe)

2014-01-01

349

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

Code of Federal Regulations, 2010 CFR

...performance requirements for school bus rollover protection. S2. Purpose...that result from failure of the school bus body structure to withstand forces encountered... This standard applies to school buses. S4. Requirements. When a...

2010-10-01

350

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

Code of Federal Regulations, 2011 CFR

...SAFETY STANDARDS Federal Motor Vehicle Safety Standards § 571.220 Standard No. 220; School bus rollover protection. S1. Scope. This standard establishes performance requirements for school bus rollover protection. S2. Purpose....

2011-10-01

351

Single chip Bus Interface Unit eases MIL-STD-1553B remote terminal/bus controller designs  

NASA Astrophysics Data System (ADS)

A new single-chip 'Smart' Bus Interface Unit (BIU), which is basically a communications processor on a chip, has been developed for use as a remote terminal and a bus controller with MIL-STD-1553B. The BIU design approach allows for future multiplex terminals without the software or BIU becoming obsolete. The use of BIU without a processor and with 8-bit, 16-bit, and other microprocessors is discussed. A sample application with the M68000 microprocessor and the inherent flexibility of the proposed design for future applications are demonstrated.

Schaire, S.; Cavin, J.

352

Implementation of field-bus interface with high performance hydraulic proportional valve  

Microsoft Academic Search

In this paper, the key technologies of electro-hydraulic control system to the requirements of field-bus interface, CAN-Bus application layer protocol as well as electro-hydraulic equipment protocol are introduced. The CAN-Bus hardware interface circuits, software system function and working models of a high-performance electro-hydraulic proportional valve are given. It provides the technical support to field-bus interface design of high-performance electro-hydraulic proportional

Hongyan Hao; Qingshan Ji

2010-01-01

353

A New Secure Architecture of Network Computer Based on Single CPU and Dual Bus  

Microsoft Academic Search

Internet is facing a serious problem: open and security. Private data, such as credit card information, login account and password, and etc., is easily theft by hackers. In this paper, we propose a new secure architecture of network computer (SANC). This new architecture is aimed to build a kind of low-cost intrusion-free network computer and reduce vulnerability of Neumann model.

Fengjing Shao; Rencheng Sun; Kegang Diao; Xiaopeng Wang

2008-01-01

354

Status Report on the P896 Backplane Bus  

Microsoft Academic Search

This report on the activities of the P896 (Advanced Microcomputer System Backplane Bus) Subcommittee of the Computer Society's Microprocessor Standards Committee describes the origins of the subcommittee and the status of the proposed specification as of its December 11, 1980 meeting. It must be emphasized that, while representing the fruits of many months of effort on the part of a

Andrew Allison

1981-01-01

355

Interface For MIL-STD-1553B Data Bus  

NASA Technical Reports Server (NTRS)

Electronic control-logic subsystem acts as interface between microcontroller and MIL-STD-1553B data bus. Subsystem made of relatively small number of integrated circuits. Advantages include low power, few integrated-circuit chips, and little need for control signals.

Davies, Bryan L.; Osborn, Stephen H.; Sullender, Craig C.

1993-01-01

356

How to Cut Costs by Saving School Bus Fuel.  

ERIC Educational Resources Information Center

A program started in Washington County, Maryland in 1980 has been successful in saving school bus fuel and bringing down transportation costs incurred by its fleet of 200 buses. Driver training and motivation, as well as a partial transfer to diesel buses, are at the heart of the program. The drivers are taught five fuel saving techniques: cut…

Seiff, Hank

357

Issues in School Bus Safety: Real or Red Herring?  

ERIC Educational Resources Information Center

In many states, the greatest threat to safe student transportation is elimination of the school transportation program. Using public transit buses, large vans, smaller vehicles, or specialized equipment can cause major-issue headaches. False issues include controversies over seat belts, bus design, and optional "bells and whistles." (10…

Leeds, Robin L.

1999-01-01

358

CAN bus embedded system for lighting network applications  

Microsoft Academic Search

This paper describes a new embedded system based on CAN bus protocol for remote monitoring and controlling of lighting networks, where the network nodes are lighting lamps and environment sensors. The main characteristic of the embedded system is its non-master capability, allowing interesting applications such as: light dimming control of a single lamp, or a group one, through one lighting

Javier Diaz; Elias Rodriguez; Luis Hurtado; Hugo Cacique; Nimrod Vazquez; Agustin Ramirez

2008-01-01

359

Bus Talk: A Preliminary Analysis of Children's Decontextualized Talk  

ERIC Educational Resources Information Center

Decontextualized conversational talk has been recognized as an important foundation for young children's early literacy and academic success. In this study, the authors explore the tape-recorded conversations of 15 typically developing preschool-age children. The children's talk was recorded as they traveled home from preschool on a school bus

Marvin, Christine A.; Cline, Keely D.

2010-01-01

360

GridBus workshop J.P. Gelas L. Lefvre  

E-print Network

... · On long distance networks (IP, TCP) #12;GridBus workshop, 7th June 2003, Melbourne · Multi cluster networks ­ ->TCP / IP for all · But Grid applications need new services for transporting their data Approach ANTS Smart Packets ANCORS Messenger CANES PLAN Active Services Active Bridging Configurable Node

Lefèvre, Laurent

361

Effects of biodiesel on emissions of a bus diesel engine  

Microsoft Academic Search

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

Breda Kegl

2008-01-01

362

Assessment of Noise Levels in Terminals at Bus Stations  

Microsoft Academic Search

At more typical levels of noise in bus stations caused by the rustle and bustle of terminals and noisy vehicles, the acoustic stimulation can have a wide range of effects on people, depending on the level and on the situation in which they are exposed. Hence, it is worthwhile to evaluate the noise levels generated inside the terminals in order

F. Rodrigues; C. A. Faria

363

Sustainability provisions in the bus-scheduling problem  

Microsoft Academic Search

The traditional vehicle scheduling problem attempts to minimize capital and operating costs. However, the carbon footprint and toxic air pollutants have become an increasingly important consideration. This paper studies the bus-scheduling problem and evaluates new types of buses that use alternative energy sources to reduce emissions, including some toxic air pollutants and carbon dioxide. A time-space network based approach is

Jing-Quan Li; K. Larry Head

2009-01-01

364

Reducing address bus transition for low power memory mapping  

Microsoft Academic Search

We present low power techniques for mapping arrays in behavioral specifications to physical memory, specifically for memory intensive behaviors that exhibit regularity in their memory access patterns. Our approach exploits this regularity in memory accesses by reducing the number of transitions on the memory address bus. We study the impact of different strategies for mapping arrays in behaviors to physical

Preeti R. Panda; Nikil D. Dutt

1996-01-01

365

Manual of First Aid Practices for School Bus Drivers.  

ERIC Educational Resources Information Center

This manual is intended to assist local school authorities in California in providing the required course in instruction in first aid practices for school bus drivers. While it deals with basic principles of handling serious medical emergencies, major emphasis is on minor injuries or illnesses that are most likely to occur while students are…

Nesbitt, William R.

366

School Bus Crash Rates on Routine and Nonroutine Routes  

ERIC Educational Resources Information Center

Background: Although prior research has established that school buses are a safe form of transportation, crashes can produce catastrophic consequences. School buses have 2 types of routes: predictable, routine routes that take children to and from school and less predictable, nonroutine routes for school events. No studies have examined school bus

O'Neal, Elizabeth; Ramirez, Marizen; Hamann, Cara; Young, Tracy; Stahlhut, Mary; Peek-Asa, Corinne

2014-01-01

367

Proposed Guide for Calculating Losses in Isolated-Phase Bus  

Microsoft Academic Search

The proposed guide forms a useful document for those responsible for evaluating losses in isolated-phase bus. The Working Group plans two modifications in the final version of the guide. The first is an extension of Fig. 1 to make it more useful in the calculation of skin effect of very large enclosures. The second modification will be the inclusion of

1968-01-01

368

Exploring the effectiveness of bus rapid transit a prototype agent-based model of commuting behavior  

E-print Network

Exploring the effectiveness of bus rapid transit a prototype agent-based model of commuting a r t i c l e i n f o Available online 24 June 2011 Keywords: Bus Rapid Transit Agent-based modeling Travel behavior Mode choice a b s t r a c t The introduction of Bus Rapid Transit (BRT), typically

Illinois at Chicago, University of

369

Wireless field bus communication with software defined IR-UWB in a manufacturing environment  

Microsoft Academic Search

This paper elaborates a concept for a wireless field bus communication with software defined ultra wide band with impulse radio modulation (IR-UWB) in manufacturing environments. A wireless field bus offers an important improvement to the smart factory due to increasing requirements for connectivity, adaptability and flexibility. Former analysis showed the benefit of using UWB technology for the wireless field bus

T. Alpert; F. Lang; M. Gro?zing; M. Berroth

2010-01-01

370

Optimal Replacement of GMC Bus Engines: An Empirical Model of Harold Zurcher  

Microsoft Academic Search

This paper formulates a simple, regenerative, optimal-stopping model of bus-eng ine replacement to describe the behavior of Harold Zurcher, superinte ndent of maintenance at the Madison (Wisconsin) Metropolitan Bus Comp any. Admittedly, few people are likely to take particular interest in Harold Zurcher and bus engine replacement per se. The author focuses on a specific individual and capital good because

John Rust

1987-01-01

371

School Bus Rider Safety Education Modules for Use with Drills on School Buses.  

ERIC Educational Resources Information Center

Developed for teachers and members of the pupil transportation staff who conduct school bus drills, these 10 lesson outlines are intended for classroom instruction on school bus safety. Lessons may be adapted to fit the grade level, intelligence, and special needs of students. Topics covered are: preparing to ride the bus, boarding and proceeding…

New York State Education Dept., Albany. Div. of Physical Education, Fitness, Health, Nutrition and Safety Services.

372

Illinois Institute of Technology Shuttle Bus Service Request for Proposals Page 1 of 10  

E-print Network

Illinois Institute of Technology ­ Shuttle Bus Service Request for Proposals Page 1 of 10 Illinois Institute of Technology REQUEST FOR PROPOSAL SHUTTLE BUS SERVICES TO: Potential Respondents FROM: Dana Royal, Director, Access, Card, and Parking Services at IIT DATE: February 15, 2013 SUBJECT: Shuttle Bus Services

Heller, Barbara

373

Instructor's Behind-the-Wheel Guide for California's Bus Driver's Training Course.  

ERIC Educational Resources Information Center

Intended to help produce safe, competent California school bus drivers, this document contains instructor's materials for a bus driver education course with eight sequential skill levels, including a final appraisal. The first section contains the curriculum's purpose and objectives, the California standards for a state-certified bus driver…

California State Dept. of Education, Sacramento.

374

A kind of new ToolBus model research and implementation  

Microsoft Academic Search

Nowadays, software architecture of CASE (Computer Aided Software Engineering) environments is evolving from layered structure to bus structure. This bus structure can greatly simplify the interconnection structure among tools and facilitate the construction of distributed CASE environments. In this paper, from the viewpoint that tool integration facilities are separated from tool logic processing function, a pure model of ToolBus first

Bing Guo; Yan Shen; Jun Xie; Yong Wang; Guang-Ze Xiong

2004-01-01

375

SunLine Leads the Way in Demonstrating Hydrogen-Fueled Bus Technologies (Brochure)  

SciTech Connect

This brochure describes SunLine Transit Agency's newest advanced technology fuel cell electric bus. SunLine is collaborating with the U.S. Department of Energy's Fuel Cell Technologies Program to evaluate the bus in revenue service. This bus represents the sixth generation of hydrogen-fueled buses that the agency has operated since 2000.

Not Available

2011-01-01

376

A Metro bus or rail line is always around the corner at  

E-print Network

A Metro bus or rail line is always around the corner at USC, making it easy to get from campus to Downtown, Culver City, Hollywood and more. For information on Metro bus and rail lines, visit metro. Every time you ride a Metro bus or rail line, you make a dent in air pollution and help curb global

Zhou, Chongwu

377

SIMPLE PROCEDURE FOR CREATING DIGITIZED BUS ROUTE INFORMATION FOR INTELLIGENT TRANSPORTATION SYSTEM APPLICATIONS  

Microsoft Academic Search

The development of procedures for creating bus route information is discussed as part of a Global Positioning System (GPS)-based bus inventory database in urban transit systems for intelligent transportation system applications. In the past, bus route information was usually entered into the database through geographic information system tools. Procedures involved in data entry were often very tedious. This study utilizes

Wei-Hua Lin; Vijaybalaji Padmanabhan

2002-01-01

378

DEVELOPMENT OF ADAPTIVE TRACKING TECHNOLOGY FOR THE UNIVERSITY OF ILLINOIS AT CHICAGO SHUTTLE BUS  

E-print Network

DEVELOPMENT OF ADAPTIVE TRACKING TECHNOLOGY FOR THE UNIVERSITY OF ILLINOIS AT CHICAGO SHUTTLE BUS of Illinois, Chicago, a bus-tracking technology for the campus shuttle bus fleet is currently under are computer-based vehicle-tracking systems that measure the real-time position of each vehicle and relay

Illinois at Chicago, University of

379

Real-time Bus Information on Mobile Devices Stuart D. Maclean, Daniel J. Dailey  

E-print Network

1 Real-time Bus Information on Mobile Devices Stuart D. Maclean, Daniel J. Dailey Abstract-- We. Introduction Recent advances in computing technology have made real-time transit vehicle information systems for tracking purposes, alarm notification sys- tems telling riders their bus is close to their bus stop

380

DVS for On-Chip Bus Designs Based on Timing Error Correction Himanshu Kaul  

E-print Network

DVS for On-Chip Bus Designs Based on Timing Error Correction Himanshu Kaul Dennis Sylvester David. The approach was implemented for a 6mm memory read bus operating at 1.5GHz (0.13µm technology node critical and directly impacts the processor cycle time. The design parameters of a bus (pitch, number

Austin, Todd M.

381

Quality-of-Service Analysis of Priority Queueing Systems under Long-Range Dependent and Short-Range Dependent Traffic  

NASA Astrophysics Data System (ADS)

Priority queueing is an important and popular traffic scheduling mechanism for the provisioning of network Quality-of-Service (QoS) which has received numerous research efforts. Realistic traffic in multi-service networks exhibits heterogeneous Long-Range Dependent (LRD) and Short-Range Dependent (SRD) properties. This chapter presents an efficient and comprehensive performance model for investigating the QoS of priority queueing systems in the presence of heterogeneous LRD and SRD traffic. We derive and validate the closedform expressions of the queue length and loss probability distributions for individual traffic flows. The analytical model is used to evaluate the impact of LRD traffic on system performance under different working conditions and investigate the buffer management and allocation in priority queueing systems with QoS constraints.

Jin, Xiaolong; Min, Geyong

382

Batch Queueing in the WINNER Resource Management System Olaf Arndt1, Bernd Freisleben1, Thilo Kielmann2, Frank Thilo1  

E-print Network

environment are described. Keywords: networks of workstations, resource man- agement, batch queueing system 1 editing text, reading mail, browsing the web, or being physically absent), the idle time of work- stations

Kielmann, Thilo

383

Real life testing of a Hybrid PEM Fuel Cell Bus  

NASA Astrophysics Data System (ADS)

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.

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

384

A New Queueing Model for QoS Analysis of IEEE 802.11 DCF with Finite Buffer and Load  

Microsoft Academic Search

Quality of Service (QoS) and queue management are important issues for IEEE 802.11 systems. However, existing 2-dimensional (2-D) Markov chain models of 802.11 systems are unable to capture the complete QoS performance and queueing behavior due to the lack of an adequate finite buffer model. We present a 3-dimensional (3-D) Markov chain that integrates the 802.11 system contention resolution and

Ren Ping Liu; Gordon J. Sutton; Iain B. Collings

2010-01-01

385

Development of the bus joint for the ITER Central Solenoid  

SciTech Connect

The terminations of the Central Solenoid (CS) modules are connected to the bus extensions by joints located outside the CS in the gap between the CS and Torodial Field (TF) assemblies. These joints have very strict space limitations. Low resistance is a common requirement for all ITER joints. In addition, the CS bus joints will experience and must be designed to withstand significant variation in the magnetic field of several tenths of a Tesla per second during initiation of plasma. The joint resistance is specified to be less than 4 nOhm. The joints also have to be soldered in the field and designed with the possibility to be installed and dismantled in order to allow cold testing in the cold test facility. We have developed coaxial joints that meet these requirements and have demonstrated the feasibility to fabricate and assemble them in the vertical configuration. We introduced a coupling cylinder with superconducting strands soldered to the surface of the cable that can be installed in the ITER assembly hall and at the Cold Test Facility. This cylinder serves as a transition area between the CS module and the bus extension. We made two racetrack samples and tested four bus joints in our Joint Test Apparatus. Resistance of the bus joints was measured by a decay method and by a microvoltmeter; the value of the current was measured by the Hall probes. This measurement method was verified in the previous tests. The resistance of the joints varied insignificantly from 1.5 to 2 nOhm. One of the challenges associated with a soldered joint is the inability to use corrosive chemicals that are difficult to clean. This paper describes our development work on cable preparation, chrome removal, compaction, soldering, and final assembly and presents the test results.

Martovetsky, Nicolai N [ORNL] [ORNL; Irick, David Kim [ORNL] [ORNL; Kenney, Steven J [ORNL] [ORNL

2013-01-01

386

ITS Solutions for School Bus Safety A local intelligent transportation case study on dynamic school bus warning signs  

E-print Network

ITS Solutions for School Bus Safety A local intelligent transportation case study on dynamic school a dynamic warning sign solution, Lund set aside the idea. A Unique Funding Source Not long after Lund an ITS con- sultant. The consultant would then develop ITS solutions for a specific traffic safety

Minnesota, University of

387

Heavy traffic analysis of a Markov-modulated queue with finite capacity and general service times  

SciTech Connect

The authors consider a set of N independent sources, each of which alternates between ``on`` and ``off`` states. When a source is on, it generates a Poisson arrival stream to a finite-capacity queue with a general server. They derive the balance equations satisfied by the joint steady-state distribution of the queue length and the number of ``on`` sources. Then they analyze the problem in the heavy traffic limit where N {yields} {infinity} and the average arrival rate is nearly equal to the mean service rate. The capacity is scaled to be O({radical}N). The first two terms in the asymptotic series are characterized as solutions to elliptic partial differential equations (PDEs) with appropriate boundary conditions. The authors then develop numerical and asymptotic methods for solving these PDEs. The analysis makes use of singular perturbation techniques and special functions.

Knessl, C.; Tier, C. [Univ. of Illinois, Chicago, IL (United States). Dept. of Mathematics, Statistics and Computer Science] [Univ. of Illinois, Chicago, IL (United States). Dept. of Mathematics, Statistics and Computer Science

1998-02-01

388

Multicast Services of QoS-Aware Active Queue Management over IP Multimedia Applications  

NASA Astrophysics Data System (ADS)

Recently, the multimedia services such as IPTV, video conference emerges to be the main traffic source. When UDP coexists with TCP, it induces not only congestion collapse but also unfairness problem. In this paper, a new Active Queue Management (AQM) algorithm, called Traffic Sensitive Active Queue Management (TSAQM), is proposed for providing multimedia services. The TSAQM comprise Dynamic Weight Allocate Scheme (DWAS) and Service Guarantee Scheme (SGS), the purpose of DWAS is to allocate resource with fairness and high end-user utility, and the purpose of SGS is to determine the satisfactory threshold (TH) and threshold region (TR). Several objectives of this proposed scheme include achieving high end-user utility for video service, considering the multicast as well as unicast proprieties to meet inter-class fairness and achieving the QoS requirement by adjusting the thresholds adaptively based on traffic situations.

Hwang, I.-Shyan; Hwang, Bor-Jiunn; Chang, Pen-Ming

2010-10-01

389

Analysis of M/G/1 queueing model with state dependent arrival and vacation  

NASA Astrophysics Data System (ADS)

This investigation deals with single server queueing system wherein the arrival of the units follow Poisson process with varying arrival rates in different states and the service time of the units is arbitrary (general) distributed. The server may take a vacation of a fixed duration or may continue to be available in the system for next service. Using the probability argument, we construct the set of steady state equations by introducing the supplementary variable corresponding to elapsed service time. Then, we obtain the probability generating function of the units present in the system. Various performance indices, such as expected number of units in the queue and in the system, average waiting time, etc., are obtained explicitly. Some special cases are also deduced by setting the appropriate parameter values. The numerical illustrations are provided to carry out the sensitivity analysis in order to explore the effect of different parameters on the system performance measures.

Singh, Charan Jeet; Jain, Madhu; Kumar, Binay

2012-05-01

390

Test program to develop vibroacoustics test criteria for the Galileo bus  

NASA Technical Reports Server (NTRS)

In order to define random vibration test requirements for Galileo bus-mounted hardware, an extensive vibroacoustics test program was conducted on hardware available from the previous Voyager spacecraft development program. The Galileo test program consisted of acoustic tests on three configurations of the Voyager Dynamic Test Model bus and shaker random vibration tests on two flight-like bus equipment bay assemblies and one dummy equipment bay assembly. The primary goal of the acoustic tests was to define vibration levels at locations on the bus structure representative of inputs to bus equipment bay assemblies and to obtain response data on bus bay subassemblies for correlation with the vibration tests response data. The primary purpose of the vibration tests was to determine if the vibration tests excited subassembly responses at least as severely as the bus acoustic tests.

Kern, D. L.; Hayes, C. D.

1982-01-01

391

Dynamic control of a multiclass queue with setups and lost sales  

Microsoft Academic Search

We consider scheduling a shared machine in a two-class make-to-stock system subject to switching costs and lost sales costs for lost jobs. If the switching costs are negligible, the optimal policy has a monotonic threshold type of switching curve provided that the service times are identical. For completely symmetric systems without set-ups, it is optimal to serve the longer queue.

M. P. Van Oyen; Eungab Kim

1997-01-01

392

A heavy traffic limit theorem for a class of open queueing networks with finite buffers  

Microsoft Academic Search

We consider a queueing network of d single server stations. Each station has a finite capacity waiting buffer, and all customers served at a station are homogeneous\\u000a in terms of service requirements and routing. The routing is assumed to be deterministic and hence feedforward. A server stops\\u000a working when the downstream buffer is full. We show that a properly normalized

J. G. Dai; W. Dai

1999-01-01

393

Target of Opportunity Observing in Queue Mode at the Gemini North Observatory  

NASA Astrophysics Data System (ADS)

The Gemini Observatories primarily operate a multi-instrument queue, with observers selecting observations that are best suited to weather and seeing conditions. Queue operations give higher ranked programs a greater chance for completion than lower ranked programs requesting the same conditions and instrument configuration. Queue observing naturally lends itself to Target of Opportunity (ToO) support since the time required to switch between programs and instruments is very short, and the staff observer is trained to operate all the available instruments and modes. Gemini Observatory has supported pre-approved ToO programs since beginning queue operations, and has implemented a rapid (less than 15 minutes response time) ToO mode since 2005. The rapid response ToO mode has thus far been exclusively utilized by the Gemini community for optical and near-IR follow-up of Gamma Ray Bursts (GRBs), primarily discovered by the Swift satellite. We discuss the ToO implementation at Gemini Observatory including the ToO user interface and the procedures followed by observatory staff astronomers once a ToO trigger is received. We present the statistics of 4 years of rapid ToOs at Gemini North Observatory, and the advances in our understanding of GRBs, their host galaxies and the intergalactic medium that this important mode has enabled. Finally we discuss recent changes in both software and policy to improve standard and rapid ToO support at the Gemini Observatories. The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciìncia e Tecnologia (Brazil), and SECYT (Argentina)

Roth, Katherine; Price, P.; Gillies, K.; Walker, S.; Miller, B.

2009-01-01

394

A queueing model for a two-stage stochastic manufacturing system with overlapping operations  

Microsoft Academic Search

This paper presents analytical expressions for estimating average process batch flow times through a stochastic manufacturing\\u000a system with overlapping operations. It is shown that the traditional queueing methodology cannot be directly applied to this\\u000a setting, as the use of the overlapping operations principle causes the arrival process of sublots at the second stage to be\\u000a a non-renewal process. An embedded

I. Van Nieuwenhuyse; N. Vandaele

2005-01-01

395

Rainbow Fair Queueing: Fair Bandwidth Sharing Without Per-Flow State  

Microsoft Academic Search

Fair bandwidth sharing at routers has several advantages, includingprotection of well-behaved flows and possible simplification of endto-end congestion control mechanisms. Traditional mechanisms to achievefair sharing (e.g., Weighted Fair Queueing, Flow Random Early Discard)require per-flow state to determine which packets to drop under congestion,and therefore are complex to implement at the interior of a high-speednetwork. In recent work, Stoica et al.

Zhiruo Cao; Zheng Wang; Ellen W. Zegura

2000-01-01

396

AQCS: Adaptive Queue-Based Chunk Scheduling for P2P Live Streaming  

Microsoft Academic Search

P2P streaming has been popular and is expected to attract even more users. The challenges for P2P streaming have been on its scalability and video viewing quality. Both require efficient utilization of resources in P2P networks. This pap er proposes an adaptive queue-based chunk scheduling method. The proposed scheme can achieve high bandwidth utilization and optimal streaming rate possible in

Yang Guo; Chao Liang; Yong Liu

2008-01-01

397

Start-time fair queueing: a scheduling algorithm for integrated services packet switching networks  

Microsoft Academic Search

Abstract— We present a Start-time Fair Queueing (SFQ) al- gorithm that is computationally efficient and achieves fairness regardless of variation in a server capacity. We analyze its single server and end-to-end deadline guarantee for variable rate Fluctuation Constrained (FC) and Exponentially Bounded Fluctuation (EBF) servers. To support heterogeneous services and multiple protocol families in integrated services networks, we present a

Pawan Goyal; Harrick M. Vin; Haichen Cheng

1997-01-01

398

Frame-based Fair Queueing: A New Traffic Scheduling Algorithm for Packet-Switched Networks  

Microsoft Academic Search

this paper we introduce and analyze frame-based fair queueing, a novel traffic schedulingalgorithm for packet-switched networks. The algorithm provides end-to-end delaybounds identical to those of PGPS (packet-level generalized processor sharing), without thecomplexity of simulating the fluid-model system in the background as required in PGPS.The algorithm is therefore ideally suited for implementation in packet switches supportinga large number of sessions. Implementations

Anujan Varma; Dimitrios Stiliadis

1995-01-01

399

Socially and Individually Optimal Control of Arrivals to a GI\\/M\\/1 Queue  

Microsoft Academic Search

We study the problem of controlling the arrivals to a single-server queue with general interarrival-time distribution and exponential service-time distribution (a GI\\/M\\/1 system). Control is exercised by accepting or rejecting arriving customers or by charging entering customers a toll or entrance fee. An entering customer receives a reward, representing his utility of service. The rewards vary randomly from customer to

Shaler Stidham Jr.

1978-01-01

400

Transient M\\/M\\/1 queue variance computation using generalized Q functions  

Microsoft Academic Search

A generalized Q function representation for the transient M\\/M\\/1 queue variance is developed. The expression is highly accurate and computationally efficient, and an upper bound on the error is easily calculated. For a Q function relative error of 2×10-12 using Parl's method, the relative error of the variance is generally less than 10-9. Average execution time is of the order

P. E. Cantrell; G. R. Beall

1988-01-01

401

A logistics problem: a non-markovian queueing network model and algorithm  

Microsoft Academic Search

In this paper, a stochastic version of the classical deterministic balanced single commodity capacitated transportation network problem is presented. In this model, each arc of the network connects a supply node to a demand node and the flow of units forming along each arc of the network forms a stochastic process (i.e.G\\/M\\/1 queueing system with generally distributed interarrival time, a

B. Pourbabai

1993-01-01

402

R+WFQ: a novel SLA-supported packet fair queueing algorithm for OLT scheduler  

NASA Astrophysics Data System (ADS)

To implement both fairness and priority scheduling in OLT scheduler, this paper proposes a SLA-supported packet fair queueing algorithm named R+WFQ. It employs WFQ discipline to serve high-priority sessions and Round Robin discipline to transmit low-priority sessions in free moments existed in traditional WFQ. Computer simulation results as well as theoretic analysis show that the proposed algorithm has excellent performance in terms of the implementation complexity, fairness and delay properties.

Zou, Junni; Qi, Shijie; Song, Yingxiong; Lin, Rujian

2005-02-01

403

Effects of Bursty and Correlated Traffic on the Performance of Active Queue Management Schemes  

NASA Astrophysics Data System (ADS)

Motivated by the need of performance analysis of Active Queue Management (AQM) schemes under highly bursty and correlated traffic in multi-service networks, this paper develops an analytical model for a finite capacity queueing system with an AQM scheme subject to two heterogeneous classes of traffic which are modeled, respectively, by the bursty Markov-Modulated Poisson Process (MMPP) and non-bursty Poisson Process. The well-known MMPP is adopted for modelling bursty traffic owing to its ability to model the time-varying arrival rate and capture the important correlation between inter-arrival times while still maintaining analytical tractability. We derive the aggregate and marginal performance metrics including the mean queue length, response time, system utilization, throughput and loss probability. The accuracy of the model is validated by comparing analytical results with those obtained from simulation. We further focus on the evaluation of the effects of traffic burstiness and correlation of inter-arrival time on the aggregate performance metrics of AQM with different thresholds.

Wang, Lan; Min, Geyong; Awan, Irfan

404

Battery management system with dual-balancing mechanism for LiFePO4 battery module  

Microsoft Academic Search

This paper presents a battery management system of LiFePO4 battery module with dual-balancing mechanism. First, the employed battery management can accurately capture some important parameters of the LiFePO4 battery module, including voltage, current, temperature, and providing protection functions for the battery module. Next, these obtained parameters of the battery are transmitted to the microcontroller through the inter-integrated circuit (I2C-bus). And

Chang-Hua Lin; Hsuan-Yi Chao; Chien-Ming Wang; Min-Hsuan Hung

2011-01-01

405

Towards ubiquitous computing in Indonesia: automated bus system  

NASA Astrophysics Data System (ADS)

The traffic jam becomes the biggest problem in urban area especially in Jakarta as the capital city of Indonesia. This is due to inadequate facilities of public transportation so, people prefers to use the private vehicles. The government has given the solution to enhance that but it is still not effective and it made the situation of traffic jam became worst. This paper proposed the Automated Bus System (ABS) to improve the existing system and enhance the traffic jam problem. This bus system has the ability to ride on his own without relying on any human driver. It can recognize any obstacles and avoid any collision using stereo vision technology. RFID technology is used to improve the accuracy. Still, this whole system is monitored by human operators. If there is any failure beyond the ability of system, the human operators could recognize the problem.

Agushinta R., Dewi; Darmayantie, Astie; Rindhayanti, Hauliza; Permatasari, Jessica; H. S, D. Suryadi

2011-10-01

406

Temporal coupled mode theory in ring-bus-ring configuration  

Microsoft Academic Search

We develop the temporal coupled mode theory for the ring-bus-ring device by taking account of the energy-conservation. The presence of the center waveguide in the tri-coupler section of the RBR facilitates the interaction between the two side-coupled rings. The correspondence between the coupled mode theory in time and transfer matrix formalism (TMF) is established. A very good agreement is obtained

Y. B. Zhang; S. Darmawan; T. Mei; D. H. Zhang

2010-01-01

407

A GPS-Based On-Demand Shuttle Bus System  

Microsoft Academic Search

We propose the implementation of an on-demand system to serve requests to ride shuttles on a university campus. Assuming that each client and each shuttle bus has a GPS device, we devise two online algorithms: the k-means based algorithm, and the general pool-based algorithm. The former has two components: the first deals with the problem of assigning requests to shuttles,

Maria Vanina; Martinez Gerardo; I. Simari; Carlos D. Castillo; Nir J. Peer

408

Design of route guidance information for elderly bus passengers  

E-print Network

because the maps and schedules provided are difficult to read and understand (Ellson and Tebb, 1978a). This problem is magnified within the elderly population. This thesis attempts to design bus route guidance information so that they may be readable... no difference in legibility, readers prefer matt paper to medium or glossy paper. Sorg (1985) reports that elderly people tend to prefer blue paper, although it tends to reduce legibility. She suggests that white or yellow paper be used for reading material...

Cheng, Pei Pei

2012-06-07

409

Structure and Metrology for an Analog Testability Bus  

Microsoft Academic Search

This paper gives a proposal for an analog testability bus that could be used as the basis for a standard such as IEEE P1149.4. The proposed testability structure is imposed on the I\\/O pin cells of the analog and mixed technology ICs. It is a superset of the existing IEEE\\/ANSI 1149.1 testability standard for digital ICs and is intended to

Kenneth P. Parker; John E. Mcdermid; Stig Oresjo

1993-01-01

410

High-speed bus debug and validation test challenges  

Microsoft Academic Search

Emerging high-speed bus technologies are presenting new test challenges for engineering device debug and validation. These challenges include: multi-gigabit operating speeds, multiple time-domains, encoding schemes, non-deterministic data, DUT-synchronous clocking modes, and SerDes transceivers with tracking receivers. A key aspect of debug and validation is the requirement for at-speed functional testing, requiring high-bandwidth interfacing to maintain signal integrity at multi-Gbps data

M. Hosman

2004-01-01

411

Safety evaluation of a hydrogen fueled transit bus  

SciTech Connect

Hydrogen fueled vehicle demonstration projects must satisfy management and regulator safety expectations. This is often accomplished using hazard and safety analyses. Such an analysis has been completed to evaluate the safety of the H2Fuel bus to be operated in Augusta, Georgia. The evaluation methods and criteria used reflect the Department of Energy`s graded approach for qualifying and documenting nuclear and chemical facility safety. The work focused on the storage and distribution of hydrogen as the bus motor fuel with emphases on the technical and operational aspects of using metal hydride beds to store hydrogen. The safety evaluation demonstrated that the operation of the H2Fuel bus represents a moderate risk. This is the same risk level determined for operation of conventionally powered transit buses in the United States. By the same criteria, private passenger automobile travel in the United States is considered a high risk. The evaluation also identified several design and operational modifications that resulted in improved safety, operability, and reliability. The hazard assessment methodology used in this project has widespread applicability to other innovative operations and systems, and the techniques can serve as a template for other similar projects.

Coutts, D.A.; Thomas, J.K.; Hovis, G.L.; Wu, T.T. [Westinghouse Savannah River Co., Aiken, SC (United States)

1997-12-31

412

Ring Bus Architecture for a Solid-State Recorder  

NASA Technical Reports Server (NTRS)

A document concisely describes a ring bus architecture for a proposed solid-state recorder (SSR) that would serve as buffer of data to be transmitted from a spacecraft to Earth. This architecture would afford fault tolerance needed for reliable operation in an anticipated high-radiation environment in which traditional SSRs cannot operate reliably. Features of the architecture include one or more controller boards and multiple memory boards interconnected in a ringlike topology. The interconnections would be high-speed serial links complying with the Institute of Electrical and Electronics Engineers (IEEE) standard 1393 (which pertains to a spaceborne fiber-optic data bus). Accordingly, each controller and memory board would be equipped with an IEEE-1393-compliant ring-bus-interface unit. The ringlike topology and the multiplicity of memory boards (and, optionally, of controller boards) would afford the redundancy needed for fault tolerance. Each board would be a fault-containment region. The IEEE 1393 links could be routed so that the SSR would continue to function even in the event of multiple failures. This architecture would also support scalability over a wide range. In a fully redundant configuration, it could accommodate between 1 and 125 memory boards.

Walker, W. John; Kopf, Edward; Cox, Brian

2008-01-01

413

Pilot Survey of Subway and Bus Stop Noise Levels  

PubMed Central

Excessive noise exposure is a serious global urban health problem, adversely affecting millions of people. One often cited source of urban noise is mass transit, particularly subway systems. As a first step in determining risk within this context, we recently conducted an environmental survey of noise levels of the New York City transit system. Over 90 noise measurements were made using a sound level meter. Average and maximum noise levels were measured on subway platforms, and maximum levels were measured inside subway cars and at several bus stops for comparison purposes. The average noise level measured on the subway platforms was 86 ± 4 dBA (decibel-A weighting). Maximum levels of 106, 112, and 89 dBA were measured on subway platforms, inside subway cars, and at bus stops, respectively. These results indicate that noise levels in subway and bus stop environments have the potential to exceed recommended exposure guidelines from the World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA), given sufficient exposure duration. Risk reduction strategies following the standard hierarchy of control measures should be applied, where feasible, to reduce subway noise exposure. PMID:16802179

Neitzel, Richard; Barrera, Marissa A.; Akram, Muhammad

2006-01-01

414

An asymptotically zero power charge-recycling bus architecture for battery-operated ultrahigh data rate ULSI's  

Microsoft Academic Search

An asymptotically zero power charge recycling bus (CRB) architecture, featuring virtual stacking of the individual bus-capacitance into a series configuration between supply voltage and ground, has been proposed. This CRB architecture makes it possible to reduce not only each bus-swing but also a total equivalent bus-capacitance of the ultramultibit buses running in parallel. The voltage swing of each bus is

Hiroyuki Yamauchi; Hironori Akamatsu; Tsutomu Fujita

1995-01-01

415

Analysis of a school bus collision: mechanism of injury in the unrestrained child  

PubMed Central

Introduction The most common type of school bus crash resulting in injury and death involves the “rollover” mechanism, which may be linked to bus design. To investigate this possibility, we carried out a detailed investigation of a severe school bus crash. Methods The crash involved 12 children, passengers in the school bus. Analysis included the determination of crash dynamics by examination of physical evidence at the crash site and deformation sustained by the structure of the bus and the other vehicle involved. The mechanism of injury was determined by comparing physical evidence collected inside the bus to injuries sustained by the children. Results Two children sustained severe injuries and 1 child was killed. The most common injuries involved the head, neck and shoulder as demonstrated by 3 illustrative reports. Specified changes to school bus design, based on mechanism of injury to the occupants include, in addition to the compartmentalization now in effect, more padding to the sides of the bus, over the window headers and on the panelling between the windows. Conclusions Injuries to the head, neck and spine are the most common types when children are involved in rollover school bus collisions. For additional safety, changes to the current bus design are needed. PMID:12930103

Lapner, Peter C.; Nguyen, Duong; Letts, Mervyn

2003-01-01

416

Dual Wavelength Lasers  

NASA Technical Reports Server (NTRS)

Dual wavelength lasers are discussed, covering fundamental aspects on the spectroscopy and laser dynamics of these systems. Results on Tm:Ho:Er:YAG dual wavelength laser action (Ho at 2.1 m and Er at 2.9 m) as well as Nd:YAG (1.06 and 1.3 m) are presented as examples of such dual wavelength systems. Dual wavelength lasers are not common, but there are criteria that govern their behavior. Based on experimental studies demonstrating simultaneous dual wavelength lasing, some general conclusions regarding the successful operation of multi-wavelength lasers can be made.

Walsh, Brian M.

2010-01-01

417

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

SciTech Connect

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 help 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.

Eudy, L.; Chandler, K.

2013-01-01

418

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC  

NASA Technical Reports Server (NTRS)

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.

1999-01-01

419

CPPk/GE/c/L G-Queue and its Application to the Analysis of the Load Balancing in MPLS Networks  

E-print Network

-service pro- cesses, queues and networks. These include the compound Poisson process (CPP) in which in the queue and have streams each of which is a CPP, i.e. a Poisson point process with batch arrivals the interarrival times have generalised exponential (GE) probability distribution [8], the Markov modulated Poisson

Do, Tien Van

420

Small Explorer Data System MIL-STD-1773 fiber optic bus  

NASA Technical Reports Server (NTRS)

The MIL-STD-1773 Fiber Optic Data Bus as implemented in the GSFC Small Explorer Data System (SEDS) for the Small Explorer Program is described. It provides an overview of the SEDS MIL-STD-1773 bus components system design considerations, reliability figures, acceptance and qualification testing requirements, radiation requirements and tests, error handling considerations, and component heritage. The first mission using the bus will be launched in June of 1992.

Flanegan, Mark; Label, Ken

1992-01-01

421

Development of Fuzzy-Based Bus Rear-End Collision Warning Thresholds Using a Driving Simulator  

Microsoft Academic Search

The purpose of this paper is to develop rear-end collision warning thresholds with appropriate values of parameters for busses driving on freeways. Based on a bus-driving simulator, we design a simulation scenario of car following with emergency braking on freeways. Bus drivers working with a bus company are recruited to manipulate the simulation. The perception-reaction time, braking deceleration rate, and

Chien-Yen Chang; Ying-Ru Chou

2009-01-01

422

Implementation of de Bruijn and Kautz bus networks using waveguide holograms  

NASA Astrophysics Data System (ADS)

In this paper, we discuss multihop optical bus interconnection networks. For massive parallel computing systems, such interconnection can interconnect a large number of processing elements and reduce system latency at the same time. We give the qualitative results of De Bruijn bus network and Kautz bus network as an engineering options based on combinatorial hypergraph theory and a uniform alphabetic constructive method. We also give an implementation method via polymer based waveguide holograms.

Fa, Jinghuai; Chen, Ray T.

1998-05-01

423

A study of multiplex data bus techniques for the space shuttle  

NASA Technical Reports Server (NTRS)

A comprehensive technology base for the design of a multiplexed data bus subsystem is provided. Extensive analyses, both analytical and empirical, were performed. Subjects covered are classified under the following headings: requirements identification and analysis; transmission media studies; signal design and detection studies; synchronization, timing, and control studies; user-subsystem interface studies; operational reliability analyses; design of candidate data bus configurations; and evaluation of candidate data bus designs.

Kearney, R. J.; Kalange, M. A.

1972-01-01

424

A DiffServ Supporting And Distributed Dynamic Dual Round Robin Scheduling Algorithm on DS-CICQ  

NASA Astrophysics Data System (ADS)

A distributed dynamic dual round robin scheduling algorithm (DSDRR) that can support differential services is presented. For each scheduler, the strategy of double pointer and round robin is adopted and scheduling complexity is substantially reduced. Its quantum function, related to the status of input queue and priority, is a traffic-adaptive dynamic scheduling mechanism and is rather sensitive to the changing network; therefore, it has the traits of dynamics and fairness. It can better support differential services and guarantee the realization of QoS.

Xiuqin, Li; Luoheng, Yan; Julong, Lan

425

Dual doubly special relativity  

NASA Astrophysics Data System (ADS)

We develop the physics of dual kappa Poincare algebra, which we will call dual DSR. First, we show that the dual kappa Poincare algebra is isomorphic to de Sitter algebra and its space-time is essentially de Sitter space-time. Second, we show how to derive the coproduct rule for Beltrami and conformal coordinates of de Sitter space-time. It follows from the current literature on de Sitter relativity that the speed of light c and the de Sitter length are the two invariant scales of the physics of dual kappa Poincare. Third, we derive the first Casimir invariant of the dual kappa Poincare algebra and use this to derive an expression for the speed of light, our fourth result. Fifth, the field equation for the scalar field is derived from the Casimir invariant. The results for the coordinate speed of light and the scalar field theory are the same as in de Sitter theory in the planar coordinate basis. Thus, we have shown that the physics of the dual kappa Poincare algebra (in the dual bicrossproduct basis), which can be appropriately called dual DSR, is essentially de Sitter relativity. Sixth, we argue the existence of an observer-independent minimum momentum. Seventh, we argue heuristically that the existence of minimum momentum will lead to a dual generalized uncertainty principle. Finally, we note that dual DSR is not a quantum theory of space-time but a quantum theory of momenta.

Magpantay, Jose A.

2011-07-01

426

Asymptotically zero power charge-recycling bus architecture for battery-operated ultrahigh data rate ULSI's  

NASA Astrophysics Data System (ADS)

An asymptotically zero power charge recycling bus (CRB) architecture, featuring virtual stacking of the individual bus-capacitance into a series configuration between supply voltage and ground, has been proposed. This CRB architecture makes it possible to reduce not only each bus-swing but also a total equivalent bus-capacitance of the ultramultibit buses running in parallel. The voltage swing of each bus is given by the recycled charge-supplying from the upper adjacent bus capacitance, instead of the power line. The dramatical power reduction was verified by the simulated and measured data. According to these data, the ultrahigh data rate of 25.6 Gb/s can be achieved while maintaining the power dissipation to be less than 100 mW, which corresponds to less than 10% that of the previously reported 0.9 V suppressed bus-swing scheme, at V(sub cc) = 3.6 V for the bus width of 512 b with the bus-capacitance of 14 pF per bit operating at 50 MHz.

Yamauchi, Hiroyuki; Akamatsu, Hironori; Fujita, Tsutomu

1995-04-01

427

Data bus of on-board data system for micro-small satellite  

NASA Astrophysics Data System (ADS)

Modularized design takes great advantage to micro-small satellites. Many modules and subsystems are manufactured individually, needs a distributed on-board data system. A kind of distributed OBDS is carried out, all the modules and subsystems connect to data bus network by ESN. Many kinds of bus can be used in satellite, and CAN, UART and 802.11 represents three typical different kind. The ESN structure is given. Take CAN bus for example, the paper details the process of bus initialization, noting some facts for PnP function.

Li, Bin; Liu, Youjun

2007-11-01

428

An interactive wireless communication system for visually impaired people using city bus transport.  

PubMed

Visually impaired people have difficulty accessing information about public transportation systems. Several systems have been developed for assisting visually impaired and blind people to use the city bus. Most systems provide only one-way communication and require high-cost and complex equipment. The purpose of this study is to reduce the difficulties faced by visually impaired people when taking city buses, using an interactive wireless communication system. The system comprised a user module and a bus module to establish a direct one-to-one connection. When the user inputs 4-digit numbers, the user module immediately sends out the information. If the bus module receives the matched bus number, it buzzes and the warning LED flashes to notify the bus driver that someone is waiting to board on the bus. User tests were conducted by two visually impaired people in a simulated vehicle and a city bus. The success rate of interactive wireless communication, recognizing the arrival of the bus and boarding the correct bus reached 100% in all of the tests. The interactive wireless communication aid system is a valid and low-cost device for assisting visually impaired people to use city buses. PMID:24776720

Wang, Hsiao-Lan; Chen, Ya-Ping; Rau, Chi-Lun; Yu, Chung-Huang

2014-05-01

429

Superconducting link bus design for the accelerator project for upgrade of LHC  

SciTech Connect

The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. Fermi National Accelerator Laboratory in collaboration with Brookhaven National Laboratory was developing sub-systems for the upgrade of the LHC final focus magnet systems. Part of the upgrade called for various lengths of superconducting power transmission lines known as SC Links which were up to 100 m long. The SC Link electrically connects the current leads in the Distribution Feed Boxes to the interaction region magnets. The SC Link is an extension of the magnet bus housed within a cryostat. The present concept for the bus consists of 22 power cables, 4 x 13 kA, 2 x 7 kA, 8 x 2.5 kA and 8 x 0.6 kA bundled into one bus. Different cable and strand possibilities were considered for the bus design including Rutherford cable. The Rutherford cable bus design potentially would have required splices at each sharp elbow in the SC Link. The advantage of the round bus design is that splices are only required at each end of the bus during installation at CERN. The round bus is very flexible and is suitable for pulling through the cryostat. Development of the round bus prototype and of 2 splice designs is described in this paper. Magnetic analysis and mechanical test results of the 13 kA cable and splices are presented.

Nobrega, F.; Brandt, J.; Cheban, S.; Feher, S.; Kaducak, M.; Kashikhin, V.; Peterson, T.; /Fermilab

2011-06-01

430

Superconducting link bus design for the accelerator project for upgrade of LHC  

SciTech Connect

The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. Fermi National Accelerator Laboratory in collaboration with Brookhaven National Laboratory was developing sub-systems for the upgrade of the LHC final focus magnet systems. Part of the upgrade called for various lengths of superconducting power transmission lines known as SC Links which were up to 100 m long. The SC Link electrically connects the current leads in the Distribution Feed Boxes to the interaction region magnets. The SC Link is an extension of the magnet bus housed within a cryostat. The present concept for the bus consists of 22 power cables, 4 x 13 kA, 2 x 7 kA, 8 x 2.5 kA and 8 x 0.6 kA bundled into one bus. Different cable and strand possibilities were considered for the bus design including Rutherford cable. The Rutherford cable bus design potentially would have required splices at each sharp elbow in the SC Link. The advantage of the round bus design is that splices are only required at each end of the bus during installation at CERN. The round bus is very flexible and is suitable for pulling through the cryostat. Development of the round bus prototype and of 2 splice designs is described in this paper. Magnetic analysis and mechanical test results of the 13 kA cable and splices are presented.

Nobrega, F.; Brandt, J.; Cheban, S.; Feher, S.; Kaducak, M.; Kashikhin, V.; Peterson, T.; /Fermilab

2010-08-01

431

DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

SciTech Connect

The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The laboratory studies have included work with a Navistar V-8 turbodiesel engine, demonstration of engine operation on DME-diesel blends and instrumentation for evaluating fuel properties. The field studies have involved performance, efficiency and emissions measurements with the Champion Motorcoach ''Defender'' shuttle bus which will be converted to DME-fueling. The results include baseline emissions, performance and combustion measurements on the Navistar engine for operation on a federal low sulfur diesel fuel (300 ppm S). Most recently, they have completed engine combustion studies on DME-diesel blends up to 30 wt% DME addition.

Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Andre L. Boehman; David Klinikowski

2003-04-01

432

A new DBA algorithm supporting priority queues and fairness for EPON  

NASA Astrophysics Data System (ADS)

EPON is an emerging local subscriber access network that consists of low-cost point-to-multipoint fiber infrastructure with Ethernet. Because several ONUs use a single shared medium in EPON, it is important to control upstream traffic. An EPON allocates upstream bandwidth to ONUs using a request/permit mechanism. In this paper, we proposed a new DBA algorithm supporting multiple priority queues and evaluated its performance. The key performance of proposed algorithm through simulation is described and the simulation results show the algorithm is fair and feasible.

Jang, Seong-Ho; Kim, Jin-Man; Jang, Jong-Wook

2005-02-01

433

Implementation of PMSM speed control software based on CAN bus  

NASA Astrophysics Data System (ADS)

In this paper, the driver's hardware structure based on TMS320F28335 is introduced, the control software flow of host computer based on CAN bus is designed, the rule of CAN communication protocol is fulfilled and accordingly the hybrid programming is realized in the background of low speed and large sinusoid operation. This system can realize the CAN communication setting, download the PID parameters to DSP, operate at constant rotate speed and at given large sinusoid rotate speed. Meanwhile the dynamical monitoring and alarm are implemented. Finally the real-time display and storage of measured current, voltage and rotate speed are completed well.

Cao, Wenlun; Chen, Bei; He, Yuyao

2013-03-01

434

Multifactor-Driven Hierarchical Routing on Enterprise Service Bus  

NASA Astrophysics Data System (ADS)

Message Routing is the foremost functionality on Enterprise Service Bus (ESB), but current ESB products don't provide an expected solution for it, especially in the aspects of runtime route change mechanism and service orchestration model. In order to solve the above drawbacks, this paper proposes a multifactor-driven hierarchical routing (MDHR) model. MDHR defines three layers for message routing on ESB. Message layer gives the original support for message delivery. Application layer can integration or encapsulate some legacy applications or un-standard services. Business layer introduces business model to supplies developers with a business rule configuration, which supports enterprise integration patterns and simplifies the service orchestration on ESB.

Mi, Xueqiang; Tang, Xinhuai; Yuan, Xiaozhou; Chen, Delai; Luo, Xiangfeng

435

DC Bus Regulation with a Flywheel Energy Storage System  

NASA Technical Reports Server (NTRS)

This paper describes the DC bus regulation control algorithm for the NASA flywheel energy storage system during charge, charge reduction and discharge modes of operation. The algorithm was experimentally verified with results given in a previous paper. This paper presents the necessary models for simulation with detailed block diagrams of the controller algorithm. It is shown that the flywheel system and the controller can be modeled in three levels of detail depending on the type of analysis required. The three models are explained and then compared using simulation results.

Kenny, Barbara H.; Kascak, Peter E.

2003-01-01

436

Common Spacecraft Bus for Earth Science Decadal Survey Missions  

NASA Astrophysics Data System (ADS)

Our study assessed the overall technical and programmatic viability of a Common Spacecraft Bus (CSB) approach that could satify the requirements of multiple Earth Science Decadal Mission programs resulting in cost and schedule savings over individual programs. Our approach developed a Common Payload Interface (CPIF) concept based on assessment of TIER I mission requirements to enable flexibility to the payloads while maintaining maximum commonality in the bus design. Satellite missions in Tier 1 of the Decadal Survey are missions with a launch period beginning in 2014. Four missions are planned and will measure climate change by examining solar and earth radiation, soil moisture and freeze/thaw cycles, ice sheet height differences, surface and ice sheet deformation from natural hazards, and vegetation structure (SMAP, ICESat-2, CLARREO, and DESDynI). Our study goals and objectives were: Develop a Common Spacecraft Bus (CSB) that incorporates the defined CPIF that can be configured to meet the individual Tier I mission specific requirements with minimal impacts or changes; Develop a efficient Assembly, Integration and Test (AI&T) flow and program schedule that can accommodate multiple Observatory level spacecraft processing and provide the flexibility to respond to program changes and other schedule perturbations; Develop a ROM cost for the CSB program approach, based on the reference design and schedules; Evaluate the CSB capability to host payloads of opportunity on the Tier I spacecraft; Evaluate the CSB capability to host the Tier II missions and what changes are required from the Tier I CSB We concluded: CSB approach for Tier I missions is feasible with very good synergy; Program Execution and AI&T approaches can be defined to take maximum advantage of CSB program approach and meet required launch readiness dates; ROM cost analysis indicates that a CSB approach is viable and offers substantial savings over separate procurements The Common Spacecraft Bus Architecture has flexibility, resources and capabilities to support beyond the Tier I Missions. There is additional CSB capability that could accommodate Payloads of Opportunity (PLO’s) on the Tier I missions - Complex Tier I operational, pointing, and field of view constraints indicate that PLO’s will need to be mostly passive and have limited additional constraints - Need to be cautious that PLO modifications for individual missions do not move away from the CSB approach; The CSB architecture has the capability to support two of the five Tier II missions; The CSB can be adapted to other LEO missions besides the Earth Science TIER I and II missions (space weather, helio/astrophysics, surveillance, etc.)

Cook, T.; Klaus, K.; Elsperman, M. S.

2010-12-01

437

DC Bus Regulation With a Flywheel Energy Storage System  

NASA Technical Reports Server (NTRS)

This paper describes the DC bus regulation control algorithm for the NASA flywheel energy storage system during charge, charge reduction and discharge modes of operation. The algorithm was experimentally verified with results given in a previous paper. This paper presents the necessary models for simulation with detailed block diagrams of the controller algorithm. It is shown that the flywheel system and the controller can be modeled in three levels of detail depending on the type of analysis required. The three models are explained and then compared using simulation results.

Kenny, Barbara H.; Kascak, Peter E.

2003-01-01

438

Dual Layer CT  

Microsoft Academic Search

\\u000a Dual-energy CT enables improvement of material and possibly tissue separation when compared to regular CT. Philips Healthcare\\u000a has been successfully operating a dual-layer detector system in a modified Brilliance 64 CT scanner installed since 2005 in\\u000a Hadassah University Medical Center, Israel. The dual-layer detector acquires single x-ray source CT data using two scintillation\\u000a layers on top of each other with

Alain Vlassenbroek

439

A Conceptual Design for a Reliable Optical Bus (ROBUS)  

NASA Technical Reports Server (NTRS)

The Scalable Processor-Independent Design for Electromagnetic Resilience (SPIDER) is a new family of fault-tolerant architectures under development at NASA Langley Research Center (LaRC). The SPIDER is a general-purpose computational platform suitable for use in ultra-reliable embedded control applications. The design scales from a small configuration supporting a single aircraft function to a large distributed configuration capable of supporting several functions simultaneously. SPIDER consists of a collection of simplex processing elements communicating via a Reliable Optical Bus (ROBUS). The ROBUS is an ultra-reliable, time-division multiple access broadcast bus with strictly enforced write access (no babbling idiots) providing basic fault-tolerant services using formally verified fault-tolerance protocols including Interactive Consistency (Byzantine Agreement), Internal Clock Synchronization, and Distributed Diagnosis. The conceptual design of the ROBUS is presented in this paper including requirements, topology, protocols, and the block-level design. Verification activities, including the use of formal methods, are also discussed.

Miner, Paul S.; Malekpour, Mahyar; Torres, Wilfredo

2002-01-01

440

Indoor air quality and occupational exposures at a bus terminal.  

PubMed

This article presents an assessment of indoor air quality at a bus terminal. For this purpose, field surveys were conducted, and air samples were collected and analyzed for the presence of selected indoor air quality indicators. Mathematical modeling was performed to simulate bus emission rates, occupational exposure, and ventilation requirements to maintain acceptable indoor air quality. A sensitivity analysis based on literature-derived emission rates estimates was conducted to evaluate the effect of seasonal temperature changes within the terminal. Control measures to improve indoor air quality at the terminal are also outlined. While carbon monoxide concentrations were below the corresponding American Conference of Governmental Industrial Hygienists' (ACGIH) standards under normal operating conditions, they exceeded the 8-hr recommended average standard at peak hours and the World Health Organization (WHO) standard at all times. Total suspended particulates levels, on the other hand, were above the 24-hr American Society of Heating, Refrigerating and Air Conditioning Engineers' (ASHRAE) standard. Carbon monoxide emission rates that were estimated using the transient mass balance model correlated relatively well with those reported in the literature. Modeling results showed that the natural ventilation rate should be at least doubled for acceptable indoor air quality. While pollutant exposure levels depended on the individual activity patterns and the pollutant concentration, pollutant emissions rates within the terminal were affected mostly by the temperature with a 20-25 percent variation in carbon monoxide levels due to changes in seasonal temperatures. PMID:12791548

El-Fadel, Mutasem; El-Hougeiri, Nisrine

2003-07-01

441

Reproductive queue without overt conflict in the primitively eusocial wasp Ropalidia marginata  

PubMed Central

Colonies of the primitively eusocial wasp Ropalidia marginata consist of a single egg layer (queen) and a number of non–egg-laying workers. Although the queen is a docile individual, not at the top of the behavioral dominance hierarchy of the colony, she maintains complete reproductive monopoly. If the queen is lost or removed, one and only one of the workers [potential queen (PQ)] becomes hyperaggressive and will become the next queen of the colony. The PQ is almost never challenged because she first becomes hyperaggressive and then gradually loses her aggression, develops her ovaries, and starts laying eggs. Although we are unable to identify the PQ when the queen is present, she appears to be a “cryptic heir designate.” Here, we show that there is not just one heir designate but a long reproductive queue and that PQs take over the role of egg-laying, successively, without overt conflict, as the queen or previous PQs are removed. The dominance rank of an individual is not a significant predictor of its position in the succession hierarchy. The age of an individual is a significant predictor, but it is not a perfect predictor because PQs often bypass older individuals to become successors. We suggest that such a predesignated reproductive queue that is implemented without overt conflict is adaptive in the tropics, where conspecific usurpers from outside the colony, which can take advantage of the anarchy prevailing in a queenless colony and invade it, are likely to be present throughout the year. PMID:22908278

Bang, Alok; Gadagkar, Raghavendra

2012-01-01

442

Queueing induced by bidirectional motor motion near the end of a microtubule.  

PubMed

Recent live observations of motors in long-range microtubule (MT) dependent transport in the fungus Ustilago maydis have reported bidirectional motion of dynein and an accumulation of the motors at the polymerization-active (the plus-end) of the microtubule. Quantitative data derived from in vivo observation of dynein has enabled us to develop an accurate, quantitatively-valid asymmetric simple exclusion process (ASEP) model that describes the coordinated motion of anterograde and retrograde motors sharing a single oriented microtubule. We give approximate expressions for the size and distribution of the accumulation, and discuss queueing properties for motors entering this accumulation. We show for this ASEP model, that the mean accumulation can be modeled as an M/M/? queue that is Poisson distributed with mean F(arr)/p(d), where F(arr) is the flux of motors that arrives at the tip and p(d) is the rate at which individual motors change direction from anterograde to retrograde motion. Deviations from this can in principle be used to gain information about other processes at work in the accumulation. Furthermore, our work is a significant step toward a mathematical description of the complex interactions of motors in cellular long-range transport of organelles. PMID:21230500

Ashwin, Peter; Lin, Congping; Steinberg, Gero

2010-11-01

443

Reproductive queue without overt conflict in the primitively eusocial wasp Ropalidia marginata.  

PubMed

Colonies of the primitively eusocial wasp Ropalidia marginata consist of a single egg layer (queen) and a number of non-egg-laying workers. Although the queen is a docile individual, not at the top of the behavioral dominance hierarchy of the colony, she maintains complete reproductive monopoly. If the queen is lost or removed, one and only one of the workers [potential queen (PQ)] becomes hyperaggressive and will become the next queen of the colony. The PQ is almost never challenged because she first becomes hyperaggressive and then gradually loses her aggression, develops her ovaries, and starts laying eggs. Although we are unable to identify the PQ when the queen is present, she appears to be a "cryptic heir designate." Here, we show that there is not just one heir designate but a long reproductive queue and that PQs take over the role of egg-laying, successively, without overt conflict, as the queen or previous PQs are removed. The dominance rank of an individual is not a significant predictor of its position in the succession hierarchy. The age of an individual is a significant predictor, but it is not a perfect predictor because PQs often bypass older individuals to become successors. We suggest that such a predesignated reproductive queue that is implemented without overt conflict is adaptive in the tropics, where conspecific usurpers from outside the colony, which can take advantage of the anarchy prevailing in a queenless colony and invade it, are likely to be present throughout the year. PMID:22908278

Bang, Alok; Gadagkar, Raghavendra

2012-09-01

444

Bus Rapid Transit Impacts on Land Uses and Land Values in Seoul, Korea  

E-print Network

are turning to Bus Rapid Transit (BRT) as a way of cost- effectively expanding public transit services to help relieve traffic congestion, reduce carbon emissions, and increase mobility options for the poor. BecauseBus Rapid Transit Impacts on Land Uses and Land Values in Seoul, Korea Robert Cervero and Chang

California at Berkeley, University of

445

SIP as a Universal Communication Bus: A Methodology and an Experimental Study  

E-print Network

communication bus. This industry standard for Internet telephony provides a basis to address the challengesSIP as a Universal Communication Bus: A Methodology and an Experimental Study B. Bertran, C. Consel--This paper describes a methodology and a pro- gramming support that use the SIP protocol as a universal

Paris-Sud XI, Université de

446

School Bus Routing and Scheduling: When to Use Computer-Assisted Methods and Programs.  

ERIC Educational Resources Information Center

Discusses issues concerning the use of computers in school bus scheduling and routing. Examines the advantages, technical considerations, and costs of changing to a computerized system. Offers a five-point approach toward implementation and includes a table of comparative data for routing and scheduling models for a typical school bus fleet. (IW)

Walcott, Wayne; And Others

1986-01-01

447

Bus Str Sustainability Spring 2011 MGT 6359: BUSINESS STRATEGIES FOR SUSTAINABILITY  

E-print Network

Bus Str Sustainability Spring 2011 1/11 MGT 6359: BUSINESS STRATEGIES FOR SUSTAINABILITY Professor and management tools Corporate environmental programs Sustainable development Environmental marketing and capitalizing on these opportunities. #12;Bus Str Sustainability Spring 2011 2/11 Course Outline The course

Li, Mo

448

Fatigue Issues for Metropolitan Bus Drivers: Ramifications of Quantitative & Qualitative Research Findings for Safety Management  

Microsoft Academic Search

Metropolitan bus drivers operating in urban areas are exposed daily to a stressful and distracting work environment. To date, there has been a dearth of research exploring whether these factors cause fatigue in this population. The present study aimed to provide insight into metropolitan bus driver fatigue. The study was conducted in two phases. Firstly, focus groups were held at

H. C. Biggs

449

INCLUSIVE SERVICES: THE URBAN TRANSPORTATION PLANNING GAP IN PUBLIC BUS PROVISION IN METROPOLITAN LAGOS, NIGERIA  

Microsoft Academic Search

Public bus infrastructural provision for the movement of people, especially commuters, by cities authorities has continued to gain prominence worldwide. This is not only because it provides enhanced access to the urban poor, but also because of the fact that researches have proven that public bus infrastructure provision provides a sustainable and green alternative to cars. In view of the

Joshua A. Odeleye

2010-01-01

450

This Could Save Your Child's Life. A School Bus Handrail Handbook.  

ERIC Educational Resources Information Center

School-bus handrails have had the same basic design for more than 30 years. However, students' recent propensity to wear oversized and baggy clothing increases the likelihood that clothing or accessories may become snagged on bus handrails. Children across the United States have been injured or killed when their clothing or accessories caught in…

National Highway Traffic Safety Administration (DOT), Washington, DC.

451

Influence of bus partitioning on the reliability of transmissions Damien AZA-VALLINAa  

E-print Network

Influence of bus partitioning on the reliability of transmissions Damien AZA-VALLINAa , Bruno; several commercial solutions (Ethernet-based industrial networks like Profinet, Powerlink or AFDX in these partitions? To answer correctly to these questions, the influence of bus partitioning on the reliability

Paris-Sud XI, Université de

452

Crime on bus routes: an evaluation of a safer travel initiative  

Microsoft Academic Search

This paper reports the main findings of an evaluation of an intensive four-week policing operation along a single bus corridor, aimed at reducing the extent of crime along the bus route. The evaluation, which adopts a mixture of quantitative evaluation techniques, demonstrates that the operation was successful both in increasing officer arrest rates (up to four times for the officers

Andrew D. Newton; Shane D. Johnson; Kate J. Bowers

2004-01-01

453

A Fuzzy Logic Based Regenerative Braking Regulation For a Fuel Cell Bus  

Microsoft Academic Search

For a fuel cell bus, it is significant to equip the regenerative break system to enhance the fuel economy. A two-input, one-output Mamdani's fuzzy inference system is introduced to the regenerative braking model. Taking the safety working conditions of the batteries, the driving dynamics and the occupant comfort into consideration, the method can not only recycle the bus braking energy

Jie Yao; Zaimin Zhong; Sun Zechang

2006-01-01

454

University of MinnesotaUniversity of Minnesota Mining Bus Location, Passenger Count and  

E-print Network

University of MinnesotaUniversity of Minnesota Mining Bus Location, Passenger Count and Fare Metro Transit !! Potential Applications of Data Mining ·! Bus scheduling and planning ·! TransferUniversity of Minnesota Time-Space Diagram EarlyOn time Late Dwell Time Slope = Average Speed SNUN FAUN EMUN OAWA ANHA 4

Minnesota, University of

455

An Integrated Framework to Predict Bus Travel Time and Its Variability Using Traffic Flow Data  

Microsoft Academic Search

Information about bus travel time and its variability is a key indicator of service performance, and it is valued by passengers and operators. Despite the important effect of traffic flow on bus travel time, previous predictive approaches have not fully considered a traffic measure making their predictions unresponsive to the dynamic changes in traffic congestion. In addition, existing methodologies have

Ehsan Mazloumi; Geoff Rose; Graham Currie; Majid Sarvi

2011-01-01

456

Design and Analysis of Low Power Dynamic Bus Based on RLC simulation  

Microsoft Academic Search

In this paper, we propose a low power dynamic bus encoding scheme which simultaneously reduces the capacitive and inductive effects by the measurement of real RLC model. It should be noted that our method does not need a sufficient knowledge of the patterns on the bus. Our experimental results show that the proposed approach can save power consumption of the

Shanq-jang Ruan; Shang-fang Tsai; Yu-ting Pai

2007-01-01

457

Automatic Bus Matrix Synthesis based on Hardware Interface Selection for Fast Communication Design Space Exploration  

Microsoft Academic Search

In this paper, we present an automated bus matrix synthesis flow for efficient system-on-chip communication design space exploration at the transaction level. Especially, we consider hardware interface design, since it affects overall system cost and performance. Depending on the bus interface, a hardware block can be a master or a slave. We propose a method to solve such hardware interface

Ganghee Lee; Seokhyun Lee; Yongjin Ahn; Kiyoung Choi

2007-01-01

458

A Comparison of State Methods of Purchasing School Bus Bodies. Monographs in Education No. 6.  

ERIC Educational Resources Information Center

The purpose of this study was to explore alternative methods for saving public funds in the purchasing of school bus bodies in the state of Georgia. Officials from each of the 50 states responded to a questionnaire that solicited descriptions of the methods used by state officials in purchasing school bus bodies. The discussion focuses on (1) the…

Bryans, Charles Michael

459

49 CFR 571.221 - Standard No. 221, School bus body joint strength.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Standard No. 221, School bus body joint strength. 571.221 Section 571.221 Transportation...Safety Standards § 571.221 Standard No. 221, School bus body joint strength. S5.2.1 The requirements of...

2011-10-01

460

Use of the cars and bus at Conservation Biology 1/2 21/09/2010  

E-print Network

Use of the cars and bus at Conservation Biology 1/2 21/09/2010 General rules: The following rules below. The organization and supervision of the Conservation Biology cars and bus is done by one as a car is borrowed by a student or any other collaborator of the division the main responsibility

Richner, Heinz

461

Design of a Distributed Multiaxis Motion Control System Using the IEEE1394 Bus  

Microsoft Academic Search

This paper presents a distributed multiaxis motion control system based on the IEEE-1394 bus. In the system design, the Unified Modeling Language is employed to illustrate interactions of the objects required in the system. The developed system consists of a set of smart distributed control nodes connected one by one through the IEEE-1394 bus. Each smart node contains four modules,

GuoYing Gu; LiMin Zhu; ZhenHua Xiong; Han Ding

2010-01-01

462

Dual Gravity and Matter  

E-print Network

We consider the problem of finding a dual formulation of gravity in the presence of non-trivial matter couplings. In the absence of matter a dual graviton can be introduced only for linearised gravitational interactions. We show that the coupling of linearised gravity to matter poses obstructions to the usual construction and comment on possible resolutions of this difficulty.

Eric A. Bergshoeff; Mees de Roo; Sven F. Kerstan; Axel Kleinschmidt; Fabio Riccioni

2008-03-13

463

Dual drive actuators  

NASA Technical Reports Server (NTRS)

A new class of electromechanical actuators is described. These dual drive actuators were developed for the NASA-JPL Galileo Spacecraft. The dual drive actuators are fully redundant and therefore have high inherent reliability. They can be used for a variety of tasks, and they can be fabricated quickly and economically.

Packard, D. T.

1982-01-01

464

The Dual Career Family.  

ERIC Educational Resources Information Center

The dual career couple is forced to make a series of choices and compromises that impact the realms of marriage and career. The dilemmas that confront dual career marriages can be overcome only by compromise, accommodation, and mutual understanding on the part of the individuals involved. A revamping of human resources and recruitment programs is…

Gurtin, Lee

1980-01-01

465

Dual Enrollment Academy Programs  

ERIC Educational Resources Information Center

Dual Enrollment Engineering (DEEA) and Medical Science (DEMSA) Academies are two-year dual enrollment programs for high school students. Students explore engineering and medical careers through college coursework. Students prepare for higher education in engineering and medical fields while completing associate degrees in biology or engineering…

Gonzalez, Nicolas; Chavez, Guadalupe

2009-01-01

466

Bus passenger origin-destination estimation and travel behavior using automated data collection systems in London, UK  

E-print Network

This research explores the application of archived data from Automatic Data Collection Systems (ADCS) to transportation planning with a focus on bus passenger Origin-Destination (OD) inferences at the bus-route level and ...

Wang, Wei, S.M. Massachusetts Institute of Technology

2010-01-01

467

49 CFR 1331.5 - Additional standards for retaining antitrust immunity by passenger bus industry rate bureaus.  

Code of Federal Regulations, 2011 CFR

...retaining antitrust immunity by passenger bus industry rate bureaus. 1331.5 Section 1331...retaining antitrust immunity by passenger bus industry rate bureaus. (a) Rate bureaus...modifies in a relatively non-uniform fashion the relationship between most...

2011-10-01

468

49 CFR 1331.5 - Additional standards for retaining antitrust immunity by passenger bus industry rate bureaus.  

Code of Federal Regulations, 2013 CFR

...retaining antitrust immunity by passenger bus industry rate bureaus. 1331.5 Section 1331...retaining antitrust immunity by passenger bus industry rate bureaus. (a) Rate bureaus...modifies in a relatively non-uniform fashion the relationship between most...

2013-10-01

469

49 CFR 1331.5 - Additional standards for retaining antitrust immunity by passenger bus industry rate bureaus.  

Code of Federal Regulations, 2012 CFR

...retaining antitrust immunity by passenger bus industry rate bureaus. 1331.5 Section 1331...retaining antitrust immunity by passenger bus industry rate bureaus. (a) Rate bureaus...modifies in a relatively non-uniform fashion the relationship between most...

2012-10-01

470

Running time variability and resource allocation : a data-driven analysis of high-frequency bus operations  

E-print Network

Running time variability is one of the most important factors determining service quality and operating cost of high-frequency bus transit. This research aims to improve performance analysis tools currently used in the bus ...

Sánchez-Martínez, Gabriel Eduardo

2013-01-01

471

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC  

NASA Technical Reports Server (NTRS)

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.

1999-01-01

472

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC  

NASA Technical Reports Server (NTRS)

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.

1999-01-01

473

Hydrogen-oxygen driven Zero Emissions bus draws attention at KSC  

NASA Technical Reports Server (NTRS)

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.

1999-01-01

474

Contribution analysis of bus pass-by noise based on dynamic transfer path method  

NASA Astrophysics Data System (ADS)

Bus pass-by noise has become one of the main noise sources which seriously disturb the mental and physical health of urban residents. The key of reducing bus noise is to identify major noise source. In this paper the dynamic transfer characteristic model in the process of bus acceleration is established, which can quantitatively describe the relationship between the sound source or vibration source of the vehicle and the response points outside the vehicle; also a test method has been designed, which can quickly and easily identify the contribution of the bus pass-by noise. Experimental results show that the dynamic transfer characteristic model can identify the main noise source and their contribution during the acceleration, which has significance for the bus noise reduction.

Liu, Haitao; Zheng, Sifa; Hao, Peng; Lian, Xiaomin

2011-10-01

475

The infinite server queue with arrivals generated by a non-homogeneous compound poisson process and heterogeneous customers  

Microsoft Academic Search

We consider the infinite server queue where customers arrive in groups of various sizes according to a non-homogeneous Poisson process. The customers in each group may be of different types and also may have dependent service times. Assuming that the system is initially empty, we obtain the probability generating function of the transient distribution of the numbers of customers of

Economou Antonis; Fakinos Demetrios

1999-01-01

476

Queueing-Based Analysis of Broadcast Optical Networks * Martin W. McKinnon+, George N. Rouskad, Harry G. Pcrrd  

E-print Network

it possible to study t,hr interactions among the system parameters, and to predict, explain and fine tune that mask the transceiver tuning latency. We dcvclop and analyze a queueing model of the network in order destination probabilities and two-state MMBP t.raf- fit sources; the latter naturally capture the notion

477

52 December/January 2003-2004 QUEUE rants: feedback@acmqueue.com echnology has made it possible for organiza-  

E-print Network

of culture: national, regional, occupational, organizational, avocational, and genera- tional. Any of these might have important effects. Here we focus on national culture, assuming that knowing at least what52 December/January 2003-2004 QUEUE rants: feedback@acmqueue.com Culture T echnology has made

Olson, Judith S.

478

Optimality of monotonic policies for two-action Markovian decision processes, with applications to control of queues with delayed information  

Microsoft Academic Search

We consider a discrete-time Markov decision process with a partially ordered state space and two feasible control actions in each state. Our goal is to find general conditions, which are satisfied in a broad class of applications to control of queues, under which an optimal control policy is monotonic. An advantage of our approach is that it easily extends to

Eitan Altman; Shaler Stidham Jr.

1995-01-01

479

Simulation-Based Computation of the Workload Correlation Function in a Levy-Driven Queue (2010 Update).  

National Technical Information Service (NTIS)

In this paper we consider a single-server queue with Levy input, and in particular its workload process (Q(sub t))t greater than or equal to 0, focusing on its correlation structure. With the correlation function defined as r(t): equals Cov(Q(sub 0))(Q(su...

M. Mandjes, P. W. Glynn

2010-01-01

480

A COMPARISON OF AIRCRAFT TRAJECTORY-BASED AND AGGREGATE QUEUE-BASED CONTROL OF AIRPORT TAXI PROCESSES  

E-print Network

in the design philosophy as the individual aircraft-based approach assumes more equipage and control authorityA COMPARISON OF AIRCRAFT TRAJECTORY-BASED AND AGGREGATE QUEUE-BASED CONTROL OF AIRPORT TAXI of aircraft at airports by optimizing surface operations. A simple surface traffic optimization approach

Gummadi, Ramakrishna

481

Tze Sing Eugene Ng eugeneng@cs.cmu.edu Carnegie Mellon University 1 Packet Fair Queueing Algorithms for  

E-print Network

Tze Sing Eugene Ng eugeneng@cs.cmu.edu Carnegie Mellon University 1 Packet Fair Queueing Algorithms for Wireless Networks with Location- Dependent Errors T. S. Eugene Ng, Ion Stoica, Hui Zhang School of Computer Science Carnegie Mellon University #12;Tze Sing Eugene Ng eugeneng@cs.cmu.edu Carnegie Mellon University 2

Ng, T. S. Eugene

482

A VLSI Self-Compacting Buffer for Priority Queue Scheduling Suryanarayana B. Tatapudi and Jos G. Delgado-Frias  

E-print Network

of a self-compacting buffer (SCB) for the dynamically allocated multi-queue (DAMQ) switch architecture. The SCB dynamically allocates data regions within the output buffer for different priority values and novel circuitry. The major components of SCB are described in detail in this paper. The system has

Delgado-Frias, José G.

483

2002 Conference on Information Sciences and Systems, Princeton University, March 2022, 2002 Twinflows: Markov Chain Flow Decomposition for Tandem Queues  

E-print Network

2002 Conference on Information Sciences and Systems, Princeton University, March 20­22, 2002 -- In this short paper it is reported that the circulatory structure of two tandem finite buffer queues using-product form network, the circulatory structure would consist of some arbitrary pattern of flows. Thus

Robertazzi, Thomas G.

484

Microbial Air Quality in Mass Transport Buses and Work-Related Illness among Bus Drivers of Bangkok Mass Transit Authority  

Microsoft Academic Search

The air quality in mass transport buses, especially air-conditioned buses may affect bus drivers who work full time. Bus numbers 16, 63, 67 and 166 of the Seventh Bus Zone of Bangkok Mass Transit Authority were randomly selected to investigate for microbial air quality. Nine air-conditioned buses and 2-4 open-air buses for each number of the bus (36 air-conditioned buses

Pipat Luksamijarulkul; Viboonsri Sundhiyodhin BN; Soavalug Luksamijarulkul; Orawan Kaewboonchoo

485

Baseline Testing of the Hybrid Electric Transit Bus  

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

486

Novel low cost standardized Nano-Satellite structure bus for LEO missions  

NASA Astrophysics Data System (ADS)

This paper focuses on SRMSAT STRUCTURE BUS which is a standardized Nano-Satellite structure bus. It provides a standard platform for a wide variety of missions in LEO and can be realized in a very short developmental period. The bus was designed and developed for SRMSAT, the SRM University (Sri Ramaswamy Memorial University) student Nano-Satellite, by the undergraduate students and faculty of SRM University in collaboration with Indian Space Research Organization (ISRO). The bus can support payloads up to a mass of 20kg. SRMSAT STRUCTURE BUS has a mass of around 6 kg and dimensions 280mm × 280mm × 280mm with an available volume of 11000 cc. Vibration Testing of the bus has been performed upto 6.7 gRMS. This makes the satellite capable of being launched by any launch vehicle in the world. An innovative PCB mounting design has been introduced in this structure bus which facilitates mounting of a maximum 7 PCB trays independently, each tray capable of holding a 250 mm2 PCB. Structural analysis of SRMSAT STRUCTURE BUS was done using NX Nastran. The boundary conditions for each analysis were defined based on the loading conditions as specified by the launcher, PSLV (Polar Satellite Launch Vehicle). Optimization of each individual component was performed by maintaining a minimum threshold between the local frequencies of the component and global frequencies of the entire satellite. Static, Modal, Harmonic and Random Vibration analysis of the structure bus was performed. This paper also describes the methodology followed in the static and dynamic analysis of the structure bus to finalize the design. The results have been tested and validated at ISRO Satellite Centre, Bangalore with around 90% accuracy and the structure has been certified as a standard structure bus for Nano-satellite missions. In terms of expandability, this structure bus is capable of accommodating deployable solar panels. Also, the payload mounting is not only restricted to th- bottom deck but can also be done in the top or side decks as required for specific missions. This enhances the scope of small satellites which has not been possible with previous satellites of the same size. SRMSAT which utilized this bus was launched on-board PSLV C-18 on 12th October 2011 with the scientific objective of measuring greenhouse gases, namely CO2 and H2O.

Anubhav, T.; Sarwesh, P.; Narayan, V.; Varma, P. A.; Prasad, R. A.; Loganathan, M.; Rao, D. N.; Sriram, S.; Venkatesh, M.

487

Optimal dual frames for erasures  

Microsoft Academic Search

For any given frame (for the purpose of encoding) in a finite dimensional Hilbert space, we investigate its dual frames that are optimal for erasures (for the purpose of decoding). We show that in general the canonical dual is not necessarily optimal. Moreover, optimal dual frames are not necessarily unique. We present some sufficient conditions under which the canonical dual

Jerry Lopez; Deguang Han

2010-01-01

488

A Closed Network Queue Model of Underground Coal Mining Production, Failure, and Repair  

NASA Technical Reports Server (NTRS)

Underground coal mining system production, failures, and repair cycles were mathematically modeled as a closed network of two queues in series. The model was designed to better understand the technological constraints on availability of current underground mining systems, and to develop guidelines for estimating the availability of advanced mining systems and their associated needs for spares as well as production and maintenance personnel. It was found that: mine performance is theoretically limited by the maintainability ratio, significant gains in availability appear possible by means of small improvements in the time between failures the number of crews and sections should be properly balanced for any given maintainability ratio, and main haulage systems closest to the mine mouth require the most attention to reliability.

Lohman, G. M.

1978-01-01

489

Modeling and Control of Airport Queueing Dynamics under Severe Flow Restrictions  

NASA Technical Reports Server (NTRS)

Based on field observations and interviews with controllers at BOS and EWR, we identify the closure of local departure fixes as the most severe class of airport departure restrictions. A set of simple queueing dynamics and traffic rules are developed to model departure traffic under such restrictions. The validity of the proposed model is tested via Monte Carlo simulation against 10 hours of actual operations data collected during a case-study at EWR on June 29,2000. In general, the model successfully reproduces the aggregate departure congestion. An analysis of the average error over 40 simulation runs indicates that flow-rate restrictions also significantly impact departure traffic; work is underway to capture these effects. Several applications and what-if scenarios are discussed for future evaluation using the calibrated model.

Carr, Francis; Evans, Antony; Clarke, John-Paul; Deron, Eric

2003-01-01

490

Dual doubled geometry  

NASA Astrophysics Data System (ADS)

We probe doubled geometry with dual fundamental branes, i.e. solitons. Restricting ourselves first to solitonic branes with more than two transverse directions we find that the doubled geometry requires an effective wrapping rule for the solitonic branes which is dual to the wrapping rule for fundamental branes. This dual wrapping rule can be understood by the presence of Kaluza-Klein monopoles. Extending our analysis to supersymmetric solitonic branes with less than or equal to two transverse directions we show that such solitons are precisely obtained by applying the same dual wrapping rule to these cases as well. This extended wrapping rule cannot be explained by the standard Kaluza-Klein monopole alone. Instead, it suggests the existence of a class of generalized Kaluza-Klein monopoles in ten-dimensional string theory.

Bergshoeff, Eric A.; Riccioni, Fabio

2011-08-01

491

Single Axis Attitude Control and DC Bus Regulation with Two Flywheels  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

492

Single Axis Attitude Control and DC Bus Regulation With Two Flywheels  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

493

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

PubMed

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. PMID:15592444

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

494

Dual stage passive vibration isolation for optical interferometer missions  

NASA Astrophysics Data System (ADS)

Future space-based optical instruments such as the Space Interferometer Mission have vibration-induced error allocations at the levels of a few nano-meters and milli-arc-seconds. A dual stage passive isolation approach has been proposed using isolation first at the vibration-inducing reaction wheels, and a second isolation layer between the bus portion of the space vehicle (the backpack) and the optical payload. The development of the backpack isolator is described, with unit transmissibility results for individual isolator struts. The dual stage isolation approach is demonstrated on a dynamically feature-rich, 7-meter structural testbed (STB3). A new passive suspension that mitigates ground vibrations above 0.4 Hz has been integrated into the testbed. A series of OPD performance predictions have been made using measured transfer functions. These indicate that the 5-nm dynamic OPD allocation is within reach using the dual isolator approach. Demonstrating these low response levels in a noisy air environment has proven to be difficult. We are sequentially executing a plan to mitigate acoustic transmission between backpack and flight structure, as well as developing techniques to mitigate effects of background acoustic noise.

Bronowicki, Allen J.; MacDonald, Rhonda; Gürsel, Yekta; Goullioud, Renaud; Neville, Timothy; Platus, David L.

2003-02-01

495

A study of the accuracy of the Bernoulli approximation of the slot occupancy process in high-speed unidirectional-bus networks  

Microsoft Academic Search

Analytical models for unidirectional-bus protocols often employ a Bernoulli process to approximate the occupancy process of the slots on the bus. This approximation, which assumes independence among the statuses of consecutive slots on the bus facilitates analysis; however, it is known to provide inaccurate results, especially for stations located at the downstream end of the bus. In this paper, we

G. J. Miller; M. Paterakis

1994-01-01

496

DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

SciTech Connect

The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. The strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. Within the Combustion Laboratory of the Penn State Energy Institute, they have installed and equipped a Navistar V-8 direct-injection turbodiesel engine for measurement of gaseous and particulate emissions and examination of the impact of fuel composition on diesel combustion. They have also reconfigured a high-pressure viscometer for studies of the viscosity, bulk modulus (compressibility) and miscibility of blends of diesel fuel, dimethyl ether and lubricity additives. The results include baseline emissions, performance and combustion measurements on the Navistar engine for operation on a federal low sulfur diesel fuel (300 ppm S). Most recently, they have examined blends of an oxygenated fuel additive (a liquid fuel called CETANER{trademark}) produced by Air Products, for comparison with dimethyl ether blended at the same weight of oxygen addition, 2 wt.%. While they have not operated the engine on DME yet, they are now preparing to do so. A fuel system for delivery of DME/Diesel blends has been configured and initial investigations at low DME blend ratios (around 5-10 vol%) will begin shortly. They have also performed viscosity measurements on diesel fuel, DME and 50-50 blends of DME in diesel. These tests have verified that DME has a much lower viscosity than the diesel fuel and that the viscosity of the blended fuel is also much lower than the diesel base fuel. This has implications for the injection and atomization of the DME/diesel blends.

Elana M. Chapman; Shirish Bhide; Andre L. Boehman; David Klinikowski

2003-04-01

497

DUAL EMPLOYMENT REVISED SCHEDULE REQUEST NAME: ____________________________________________________ EMPLID: ______________________________  

E-print Network

DUAL EMPLOYMENT REVISED SCHEDULE REQUEST NAME: _______________________ DUAL EMPLOYMENT DATES: ____________________ TO ______________________ TIMES: __________________ AM SCHEDULE. IN ACCORDANCE WITH THE CLEMSON UNIVERSITY DUAL EMPLOYMENT POLICY, ALL HOURS MISSED WHILE

Bolding, M. Chad

498

Leveraging infrastructure : sustainable bus rapid transit route planning in Beirut, Lebanon  

E-print Network

This thesis applies the concepts of urban design, public transportation planning, economic development, and sustainability, to the routing and site plan of a two-kilometer bus rapid transit (BRT) line segment into downtown ...

Nabti, Jumana M., 1976-

2004-01-01

499

Urban Traffic Control and Bus Priority System. Software Manual. Volume II.  

National Technical Information Service (NTIS)

An Urban Traffic Control and Bus Priority System has been implemented by the Sperry Systems Management Division in the District of Columbia under Federal Highway Administration contract No. FH-11-7605, Advanced Control Technology in Urban Traffic Control ...

1973-01-01

500

Urban Traffic Control and Bus Priority System. Sofware Manual. Volume I.  

National Technical Information Service (NTIS)

An Urban Traffic Control and Bus Priority System has been implemented by the Sperry Systems Management Division in the District of Columbia under Federal Highway Administration contract No. FH-11-7605, Advanced Control Technology in Urban Traffic Control ...

1973-01-01