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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

An efficient synchronization method for dual bus networks  

Microsoft Academic Search

The problem of the loss of synchronization in high-speed dual-bus MANs or LANs (metropolitan or local area networks) is considered, and an efficient method to recover alignment is proposed. The proposed mechanism provides for use of a particular bit pattern, called a synchronization pattern, which is inserted into the network through an empty slot. This pattern implicity defines a variable

S. Casale; A. Lombardo; S. Palazzo

1989-01-01

4

Microprocessor Based Dual Bus Structured Data Acquisition and Processing System : DAPS-80.  

National Technical Information Service (NTIS)

The microprocessor based dual bus structured data acquisition and processing system has been designed around Intel 8080 microprocessor. The system is described and operational results are given. (Atomindex citation 15:019168)

V. A. Pethe A. M. Patankar L. S. Ram A. K. Bayala M. D. Ghodgaonkar

1983-01-01

5

A dual speed, MIL-STD-1553B compatible fiber optic data bus  

NASA Astrophysics Data System (ADS)

A demonstration system of a dual speed, fiber optic data bus is described. This work is based on a previously described concept (1) which envisioned a data bus populated with MIL-STD-1553B avionic components which evolve as equipment is upgraded to higher data rates. The approach described herein provides for the coexistence of bus nodes operating at 1 Mb/s, and 20 Mb/s, on a single fiber bus medium. The 1 Mb/s interface of each node is 1553B compatible, making use of readily available hardware and software. Both existing, 1 Mb/s 1553B compatible interfaces and new equipment operating at 20 Mb/s have been shown to work simultaneously on the single bus structure. The design provides a sound, low-risk method for transitioning from current 1 Mb/s equipment to a unified bus structure incorporating both existing 1553B compatible components and newly designed higher speed equipment.

Blaha, M. S.; Degennaro, C. H.; Utley, S. F.

6

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

7

A Duality Theorem for Phase Type Queues.  

National Technical Information Service (NTIS)

A duality theorem of Heathcote exhibiting and relationship between first passage times of the queue length in the GI/M/1 queue and the busy period of its dual M/G/1 queue is generalized to the phase type queues GI/PH1 and PH/G/1. The phase type distributi...

V. Ramaswami M. F. Neuts

1978-01-01

8

Comparison of FDDI asynchronous mode and DQDB queue arbitrated mode data transmission for metropolitan area network applications  

NASA Astrophysics Data System (ADS)

The performance of the FDDI (Fiber Distributed Data Interface) token ring and IEEE 802.6 DQDB (Distributed Queue Dual Bus) protocols are compared using discrete event simulation models. A Metropolitan Area Network (MAN) of 100 km and with 50 stations was modeled. A 100 Mbps channel is used for both networks, with a traffic model with large (1 kbyte) low priority packets and smaller (100 byte) high priority packets. The delay and fairness characteristics of both networks are analyzed.

Burr, William E.; Wakid, Shukri; Qian, Xiaomei; Vaman, Dhadesugoor

1994-02-01

9

Measuring in-cabin school bus tailpipe and crankcase PM2.5: a new dual tracer method.  

PubMed

Exposures of occupants in school buses to on-road vehicle emissions, including emissions from the bus itself, can be substantially greater than those in outdoor settings. A dual tracer method was developed and applied to two school buses in Seattle in 2005 to quantify in-cabin fine particulate matter (PM2.5) concentrations attributable to the buses' diesel engine tailpipe (DPMtp) and crankcase vent (PMck) emissions. The new method avoids the problem of differentiating bus emissions from chemically identical emissions of other vehicles by using a fuel-based organometallic iridium tracer for engine exhaust and by adding deuterated hexatriacontane to engine oil. Source testing results showed consistent PM:tracer ratios for the primary tracer for each type of emissions. Comparisons of the PM:tracer ratios indicated that there was a small amount of unburned lubricating oil emitted from the tailpipe; however, virtually no diesel fuel combustion products were found in the crankcase emissions. For the limited testing conducted here, although PMck emission rates (averages of 0.028 and 0.099 g/km for the two buses) were lower than those from the tailpipe (0.18 and 0.14 g/km), in-cabin PMck concentrations averaging 6.8 microg/m3 were higher than DPMtp (0.91 microg/m3 average). In-cabin DPMtp and PMck concentrations were significantly higher with bus windows closed (1.4 and 12 microg/m3, respectively) as compared with open (0.44 and 1.3 microg/m3, respectively). For comparison, average closed- and open-window in-cabin total PM2.5 concentrations were 26 and 12 microg/m3, respectively. Despite the relatively short in-cabin sampling times, very high sensitivities were achieved, with detection limits of 0.002 microg/m3 for DPMtp and 0.05 microg/m3 for PMck. PMID:21608489

Ireson, Robert G; Ondov, John M; Zielinska, Barbara; Weaver, Christopher S; Easter, Michael D; Lawson, Douglas R; Hesterberg, Thomas W; Davey, Mark E; Liu, L-J Sally

2011-05-01

10

The network queueing system  

NASA Technical Reports Server (NTRS)

Described is the implementation of a networked, UNIX based queueing system developed on contract for NASA. The system discussed supports both batch and device requests, and provides the facilities of remote queueing, request routing, remote status, queue access controls, batch request resource quota limits, and remote output return.

Kingsbury, Brent K.

1986-01-01

11

A Multiprocessor Bus Design Model Validated by System Measurement  

Microsoft Academic Search

An accurate and efficient model of a commercial multiprocessor bus is developed. Fourimportant characteristics of the bus design are modeled: asynchronous memory writeoperations; in-order delivery of responses to processor read requests; priority schedulingof memory responses; and upper bounds on the number of outstanding processorrequests. A two-level hierarchical model employing both Markov chain and mean valueanalysis techniques for analyzing queueing networks

Thin-fong Tsuei; Mary K. Vernon

1992-01-01

12

Traffic Jam Queues.  

National Technical Information Service (NTIS)

The paper generalizes and extends the queuing model and results of McNeil (1969) for the study of a traffic jam on a single-lane highway. By allowing a vehicle to leave the queue at a slower speed than its arrival speed, the original queue may produce a f...

L. Shaw

1970-01-01

13

Queueing for Healthcare  

Microsoft Academic Search

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\\u000a ones. This established theory helps us to quantify the appropriate service capacity to meet the patient demand, balancing\\u000a system utilization and the

R. Kannapiran Palvannan; Kiok Liang Teow

14

Fussing management system in a dual voltage 14 V\\/42 V system using the communication protocol request detection bus (RDbus)  

Microsoft Academic Search

The use of the dual voltage system 14 V\\/42 V in the electric systems of cars brings many advantages, but it also poses new challenges like a bigger short circuits (SC) casuistic. The fussing management system (FMS) is responsible for managing the 14 V-gnd, 42 V-gnd and 14 V-42 V short circuits, with the objective of eliminating them as soon

Benito Perez-Solorzano; Ernest Gil Dolcet; J. M. Altes; Enric Vidal

2004-01-01

15

Dependence in packet queues  

Microsoft Academic Search

The burstiness of the total arrival process has been previously characterized in packet network performance models by the dependence among successive interarrival times. It is shown that associated dependence among successive service times and between service times and interarrival times also can be important for packet queues involving variable packet lengths. These dependence effects are demonstrated analytically by considering a

K. W. Fendick; V. R. Saksena; W. Whitt

1989-01-01

16

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

17

Modeling and analysis of single bus tightly coupled multiprocessors  

SciTech Connect

This thesis presents and analyses a stochastic queueing model for single bus tightly coupled multiprocessors. The model is based on an experimental single bus multiprocessor in operation at Illinois Institute of Technology. The model is a hierarchical one, with each processor being described by its own submodel. The submodel takes into consideration local task (group) behavior and the prioritized structure of interprocessor communication. A direct numerical analysis of the submodel is done in order to establish future test data. It is shown that each submodel can be reduced to a single queue/server pair with the service rate depending on the number of tasks in the server's queue. An analytic expression for this service rate is derived, and a CPU sensitivity analysis for it is done. Based on this reduction to a queue/server pair, multiprocessor performance (based on net bus throughput) is obtained. An approximate limiting expression for the submodel valid for heavy loads or low CPU speeds is derived and, based on this approximately expression, closed form solutions for throughput increase (over that afforded by a uniprocessor) are obtained for a system consisting of two nonhomogenous processors and for a system consisting of an arbitrary number of homogeneous processors.

Bodnar, B.L.

1986-01-01

18

75 FR 52054 - Bus and Bus Facilities Discretionary Program Funds  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF TRANSPORTATION Federal Transit Administration Bus and Bus Facilities Discretionary Program Funds AGENCY: Federal Transit Administration (FTA), DOT. ACTION: Bus and Bus Facilities Livability...

2010-08-24

19

Stability, queue length, and delay of deterministic and stochastic queueing networks  

Microsoft Academic Search

We present two types of stability problems: 1) conditions for queueing networks that render bounded queue lengths and bounded delay for customers, and 2) conditions for queueing networks in which the queue length distribution of a queue has an exponential tail with rate ?. To answer these two types of stability problems, we introduce two new notions of traffic characterization:

Cheng-Shang Chang

1994-01-01

20

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

21

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

22

Transit Bus Maintenance Management.  

National Technical Information Service (NTIS)

The 8 papers in the report deal with the following areas: some recent developments in summary; research needs in transit bus maintenance; transit bus maintenance in New York State; issues and analysis; management of transit bus prerun inspections; applica...

S. J. Andrle J. F. Zimmerman J. Duffy J. F. Foerster S. Puente

1986-01-01

23

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

24

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

25

Simulating Traffic with Queueing Models  

Microsoft Academic Search

Abstract: Queueing models for traffic simulations are interesting models for applications. They can be used to simulate up to 10^8 cars\\/s on completely standard hard-ware. Unfortunately, uptonow, there was a catch: they sometimes show weird results, most notably jams that do not run backward. This work shows how queueing models can be made as realistic as most car-following models. Two

Nils Eissfeldt; Peter Wagner

2003-01-01

26

Transit bus maintenance management  

SciTech Connect

The 8 papers in the report deal with the following areas: some recent developments in summary; research needs in transit-bus maintenance; transit-bus maintenance in New York State; issues and analysis; management of transit-bus prerun inspections; application of a transit-maintenance management-evaluation procedure; analysis of bus transit's maintenance efficiency using section 15 data; climatic effects on bus durability; exploring the multiple factor concept for bus maintenance using simulation; effectiveness of improved repair scheduling in the performance of bus-transit maintenance.

Andrle, S.J.; Zimmerman, J.F.; Duffy, J.; Foerster, J.F.; Puente, S.

1986-01-01

27

Analysis and design of an adaptive virtual queue (AVQ) algorithm for active queue management  

Microsoft Academic Search

Virtual Queue-based marking schemes have been recently proposed for AQM (Active Queue Management) in Internet routers. We consider a particular scheme, which we call the Adaptive Virtual Queue (AVQ), and study its following properties: stability in the presence of feedback delays, its ability to maintain small queue lengths and its robustness in the presence of extremely short flows (the so-called

Srisankar S. Kunniyur; Rayadurgam Srikant

2001-01-01

28

Balancing Queues by Mean Field Interaction  

Microsoft Academic Search

Consider a queueing network with N nodes in which queue lengths are balanced through mean-field interaction. When N is large, we study the performance of such a network in terms of limiting results as N goes to infinity.

Donald A. Dawson; Jiashan Tang; Yiqiang Q. Zhao

2005-01-01

29

Some Problems in Queueing Network Theory.  

National Technical Information Service (NTIS)

The study of networks of queues poses some interesting theoretical and practical problems. In the paper the author discusses one method used to study queueing networks. The method attempts to decompose the network into smaller parts (decomposition), analy...

R. L. Disney

1973-01-01

30

Theoretical and practical eciency of priority queues  

Microsoft Academic Search

Abstract This is a study of the theoretical and practical eciency,of priority queues. The priority queue is an old and well studied data structure on which a great deal of theoretical and practical work has already been done. A priority queue can be realised in many ways, some of the most commonly used data structures for this are binary heaps

Claus Jensen

2006-01-01

31

77 FR 48592 - Bus and Bus Facilities Discretionary Program Funds  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF TRANSPORTATION Federal Transit Administration Bus and Bus Facilities Discretionary...at replacing or rehabilitating transit infrastructure for buses, bus facilities, bus-related equipment, and transit asset management systems....

2012-08-14

32

The Bus Stops Here.  

ERIC Educational Resources Information Center

Explores some of the factors to consider before school planners decide to buy new school buses. Provides a checklist to help build and maintain a bus fleet. Concludes by addressing bus safety and advertising. (GR)

Milshtein, Amy

1999-01-01

33

Fuss on the Bus.  

ERIC Educational Resources Information Center

Approaches to maintaining order and discipline in school transportation include revoking or suspending a student's bus-riding privileges, using radios and video cameras, and using bus monitors. School leaders must demonstrate support for their school-bus drivers. A sidebar lists 17 suggested rules for student behavior to ensure safe…

George, Katherine L.

1995-01-01

34

Queueing theory and operations management  

Microsoft Academic Search

Waiting is an intimate dimension of our daily lives. Everyone has ex- perienced waiting in line at the supermarket, the bank and any num- ber of other places. We constantly observe traffic, hospital or court congestion, customers or machines are waiting and we experience wai- ting times for almost every service offered. These waiting-line situa- tions are also called queueing

Marc Lambrecht; Nico Vandaele

1994-01-01

35

Queueing Model with Service Interruption.  

National Technical Information Service (NTIS)

Single-server queues in which the server takes vacations arise naturally as models for a wide range of computer-, communication-, and production-systems. In almost all studies on vacation models, the vacation lengths are assumed to be independent of the a...

M. R. H. Mandjes O. Kella O. J. Boxma

2006-01-01

36

Open Networks of Queues with Blocking: Split and Merge Configurations  

Microsoft Academic Search

Split and merge configurations of open networks of queues with blocking are analyzed approximately. The approximation procedure developed decomposes these queue networks into individual queues with revised queue capacity and revised arrival and service processes. These individual queues are then analyzed in isolation. The results obtained seem to have an acceptable error level. Stability conditions for these two configurations are

Tayfur Altiok; H. G. Perros

1986-01-01

37

Message passing with queues and channels  

DOEpatents

In an embodiment, a send thread receives an identifier that identifies a destination node and a pointer to data. The send thread creates a first send request in response to the receipt of the identifier and the data pointer. The send thread selects a selected channel from among a plurality of channels. The selected channel comprises a selected hand-off queue and an identification of a selected message unit. Each of the channels identifies a different message unit. The selected hand-off queue is randomly accessible. If the selected hand-off queue contains an available entry, the send thread adds the first send request to the selected hand-off queue. If the selected hand-off queue does not contain an available entry, the send thread removes a second send request from the selected hand-off queue and sends the second send request to the selected message unit.

Dozsa, Gabor J; Heidelberger, Philip; Kumar, Sameer; Ratterman, Joseph D; Steinmacher-Burow, Burkhard; Wisniewski, Robert W

2013-09-24

38

Calendar queues: a fast 0(1) priority queue implementation for the simulation event set problem  

Microsoft Academic Search

A new priority queue implementation for the future event set problem is described in this article. The new implementation is shown experimentally to be O(1) in queue size for the priority increment distributions recently considered by Jones in his review article. It displays hold times three times shorter than splay trees for a queue size of 10,000 events. The new

Randy Brown

1988-01-01

39

Hierarchical packet fair queueing algorithms  

Microsoft Academic Search

In this paper, we propose to use the idealized HierarchicalGeneralized Processor Sharing (H-GPS) model to simultaneouslysupport guaranteed real-time, rate-adaptivebest-effort, and controlled link-sharing services. We designHierarchical Packet Fair Queueing (H-PFQ) algorithms toapproximate H-GPS by using one-level variable-rate PFQservers as basic building blocks. By computing the systemvirtual time and per packet virtual start\\/finish times in unitof bits instead of seconds, most of

Jon C. R. Bennett; Hui Zhang

1997-01-01

40

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

41

Hydrogen powered bus  

SciTech Connect

Take a ride on a new type of bus, fueled by hydrogen. These hydrogen taxis are part of a Department of Energy-funded deployment of hydrogen powered vehicles and fueling infrastructure at nine federal facilities across the country to demonstrate this market-ready advanced technology. Produced and leased by Ford Motor Company , they consist of one 12- passenger bus and one nine-passenger bus. More information at: http://go.usa.gov/Tgr

None

2011-04-07

42

Hydrogen powered bus  

ScienceCinema

Take a ride on a new type of bus, fueled by hydrogen. These hydrogen taxis are part of a Department of Energy-funded deployment of hydrogen powered vehicles and fueling infrastructure at nine federal facilities across the country to demonstrate this market-ready advanced technology. Produced and leased by Ford Motor Company , they consist of one 12- passenger bus and one nine-passenger bus. More information at: http://go.usa.gov/Tgr

None

2013-11-22

43

Impact of Arterial Bus Priority Treatments on Bus Operating Costs.  

National Technical Information Service (NTIS)

A study was conducted to ascertain whether or not an arterial bus priority treatment affects the cost of bus operations. Arterial priority treatments were evaluated for the effectiveness of operations within the Central Business District. Bus operating co...

M. S. Hirsh

1975-01-01

44

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

45

Preferences Lower Bound in the Queueing Model  

NASA Astrophysics Data System (ADS)

We show the existence of a first best incentive compatible mechanism for the queueing model that satisfies identical preferences lower bound. We call this mechanism the FB' mechanism. We also show that for the queueing model, either with three agents or with four agents, the FB' mechanism is the only first best incentive compatible mechanism that satisfies identical preferences lower bound.

Mitra, Manipushpak

46

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.

47

School Bus Safety.  

ERIC Educational Resources Information Center

Explains why fewer school students are injured are killed while being transported in school buses than any other mode of transportation. Political and community action in school bus transportation safety is addressed. (GR)

Rittner-Heir, Robbin M.

2001-01-01

48

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

49

Bus Operations and Performance.  

National Technical Information Service (NTIS)

Contents: Public transportation in the 1980s--responding to pressures of fiscal austerity; Design of bus transit monitoring programs; Performance-based funding-allocation guidelines for transit operators in Los Angeles County; Transit performance in New Y...

B. Hemily M. D. Meyer J. Attanucci N. Wilson B. McCollom

1981-01-01

50

Downtown Bus Transportation.  

National Technical Information Service (NTIS)

The research examined special downtown or small bus systems in forty cities throughout the United States. Data were collected in questionnaires received from fourteen cities using small-size buses and nine cities using standard vehicles. Emphasis is focus...

L. D. Goldstein

1972-01-01

51

Some Topics in Queueing Network Theory.  

National Technical Information Service (NTIS)

In the report the author summarize some of the major results obtained in the decomposition study of queueing networks. In particular, results for departure processes, decomposition switching, superposition and feedback, are reviewed. (Author)

W. P. Cherry R. L. Disney

1973-01-01

52

Redesigning an active queue management system  

Microsoft Academic Search

A robust proportional-integral-derivative (PID) controller is proposed for active queue management (AQM). A linear quadratic regulator (LQR) method is used to design the controller, named LQR-PID. LQR is a robust design technique as compared to classical gain-and-phase margin and dominant pole placement methods. The LQR-PID controller marks the packets according to queue length with a probability and notifies congestion to

Deepak Agrawal; Fabrizio Granelli

2004-01-01

53

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

54

The WorkQueue project - a task queue for the CMS workload management system  

NASA Astrophysics Data System (ADS)

We present the development and first experience of a new component (termed WorkQueue) in the CMS workload management system. This component provides a link between a global request system (Request Manager) and agents (WMAgents) which process requests at compute and storage resources (known as sites). These requests typically consist of creation or processing of a data sample (possibly terabytes in size). Unlike the standard concept of a task queue, the WorkQueue does not contain fully resolved work units (known typically as jobs in HEP). This would require the WorkQueue to run computationally heavy algorithms that are better suited to run in the WMAgents. Instead the request specifies an algorithm that the WorkQueue uses to split the request into reasonable size chunks (known as elements). An advantage of performing lazy evaluation of an element is that expanding datasets can be accommodated by having job details resolved as late as possible. The WorkQueue architecture consists of a global WorkQueue which obtains requests from the request system, expands them and forms an element ordering based on the request priority. Each WMAgent contains a local WorkQueue which buffers work close to the agent, this overcomes temporary unavailability of the global WorkQueue and reduces latency for an agent to begin processing. Elements are pulled from the global WorkQueue to the local WorkQueue and into the WMAgent based on the estimate of the amount of work within the element and the resources available to the agent. WorkQueue is based on CouchDB, a document oriented NoSQL database. The WorkQueue uses the features of CouchDB (map/reduce views and bi-directional replication between distributed instances) to provide a scalable distributed system for managing large queues of work. The project described here represents an improvement over the old approach to workload management in CMS which involved individual operators feeding requests into agents. This new approach allows for a system where individual WMAgents are transient and can be added or removed from the system as needed.

Ryu, S.; Wakefield, S.

2012-12-01

55

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

56

Recent advances in bus transit operations planning  

Microsoft Academic Search

The 11 papers in the report deal with the following areas: comparative evaluation of bus route costing procedures; estimating bus ridership; FRACAS: a strategic planning model for bus transit systems; limited-stop bus operations; an evaluation; operational evaluation of bus priority strategies; use of supercalc to compile and report statistics in public transportation; optimal design of bus routes and frequencies for

D. W. Carter; S. R. Mundle; B. E. McCollom; H. S. Levinson; O. B. West

1984-01-01

57

Bus-Programmable Slave Card  

NASA Technical Reports Server (NTRS)

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

Hall, William A.

1990-01-01

58

Bus deregulation: ten years on  

Microsoft Academic Search

This paper identifies the principal areas of disagreement in the bus policy debate of 1984–85, and reviews the outcome of bus deregulation against that background. It is concluded that the commercial bus market is imperfectly contestable. Entry may occur where the incumbent is inefficient, where the incumbent is efficient but weak enough to be supplanted, or simply through over?optimism. Incumbents

Peter Mackie; John Preston; Chris Nash

1995-01-01

59

Augmented thermal bus  

NASA Technical Reports Server (NTRS)

The present invention is directed to an augmented thermal bus. In the present design a plurity 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 pump to maintain isothermality in the source.

Schrage, Dean S. (inventor)

1993-01-01

60

A Low-Power Instruction Issue Queue for Microprocessors  

Microsoft Academic Search

Instruction issue queue is a key component which extracts instruction level parallelism (ILP) in modern out-of-order microprocessors. In order to exploit ILP for improving processor performance, instruction queue size should be increased. However, it is difficult to increase the size, since instruction queue is implemented by a content addressable memory (CAM) whose power and delay are much large. This paper

Shingo Watanabe; Akihiro Chiyonobu; Toshinori Sato

2008-01-01

61

The design of a graphic representation of bus route information for use at bus stops  

Microsoft Academic Search

The bus information sign at a bus stop is a basic and important means for providing bus users with necessary transportation information (e.g., bus route information). If bus route information at a bus stop is insufficient, bus passengers may have problems finding the bus route(s) and bus stop(s) required to reach their destination(s). In contrast, if too much information is

Sheng-Hsiung Chang; Wan-Hui Chen; Wan-I Lin; Szu-Yu Lin; Kui-Chuan Kao

2010-01-01

62

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

63

Queueing Networks with Blocking: A Bibliography  

Microsoft Academic Search

In recent years, queueing networks with blocking have been studied by researchers from various research communities such as Computer Performance Modelling, Operations Research, and Industrial Engineering. In view of this, related results are scattered throughout various journals. The bibliography given below is the result of a first attempt to compile an exhaustive list of related papers in which analytic investigations

Harry G. Perros

1984-01-01

64

Approximate analysis of arbitrary configurations of open queueing networks with blocking  

Microsoft Academic Search

An algorithm for analyzing approximately open exponential queueing networks with blocking is presented. The algorithm decomposes a queueing network with blocking into individual queues with revised capacity, and revised arrival and service processes. These individual queues are then analyzed in isolation. Numerical experience with this algorithm is reported for three-node and four-node queueing networks. The approximate results obtained were compared

T. Altiok; H. G. Perros

1987-01-01

65

Bus management with improved passenger situations  

Microsoft Academic Search

Bus passengers normally could be divided into those who are on the bus and those who are at the roadside bus-stop waiting for the bus. Both kinds of passengers should be at least in equal importance. This paper has described how to supply an improved environment to passengers at roadside, and how to estimate the passengers waiting at the bus

Baichuan Lu; Jost Viegas

2003-01-01

66

Mass Transit: Bus Rapid Transit Shows Promise.  

National Technical Information Service (NTIS)

Bus Rapid Transit as a comprehensive transportation option is exemplified in Curitiba, Brazil. Curitiba's Bus Rapid Transit system is an extensive commuter bus system that includes exclusive busways and a number of other features designed to increase spee...

2001-01-01

67

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

68

Monte-Carlo Bus Regulation  

Microsoft Academic Search

In this paper we want to minimize passengers waiting times at the bus stops by making buses wait at a stop. We compare a simple rule based approach to a Monte- Carlo method for this problem. When allocated enough time, the Monte-Carlo method gives better results. If the passengers arrivals and the bus travel times are known, the best algorithm

Tristan Cazenave; Flavien Balbo; Suzanne Pinson

69

Forecasting bus transit operating costs  

Microsoft Academic Search

The study deals with forecasting the cost of operating bus transit systems in U.S. cities. The primary objective is to develop a practical forecasting model for use by transit planners, i.e., a tool that will provide quantitative estimates (forecasts) of operating costs for any proposed bus transit system. The final product is a composite of several models, each of which

1975-01-01

70

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

71

Active Queue Management using Adaptive RED  

Microsoft Academic Search

Abstract Random,Early Detection (RED) [1] is an active queue management,scheme,which has been deployed extensively to reduce packet loss during congestion. Although RED can improve loss rates, its performance,depends severely on the tuning of its operating parameters. The idea of adaptively varying RED parameters to suit the network conditions has been investigated in [2], where the maximum packet dropping probability maxp

Rahul Verma; Aravind Iyer; Abhay Karandikar

2002-01-01

72

Bayesian inference for double Pareto lognormal queues  

Microsoft Academic Search

In this article we describe a method for carrying out Bayesian estimation for the double Pareto lognormal (dPlN) distribution which has been proposed as a model for heavy-tailed phenomena. We apply our approach to estimate the dPlN?\\/?M?\\/?1 and M?\\/?dPlN?\\/?1 queueing systems. These systems cannot be analyzed using standard techniques due to the fact that the dPlN distribution does not possess

Pepa Ramirez-Cobo; Rosa E. Lillo; Simon Wilson; Michael P. Wiper

2010-01-01

73

Light traffic for workload in queues  

Microsoft Academic Search

General exact light traffic limit theorems are given for the distribution of steadystate workloadV, in open queueing networks having as input a general stationary ergodic marked point process {(tn,Kn)n=0 (where tn denotes the arrival time and Kn the routing and service times of the nth customer). No independence assumptions of any kind are required of the input. As the light

Karl Sigman

1992-01-01

74

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

75

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

76

Bus Semirapid Transit Mode Development and Evaluation  

Microsoft Academic Search

With little investment required for operating in streets, bus services are often designed to serve many overlapping routes with frequent stops. To upgrade services and attract choice riders, major bus routes should be provided with exclusive lanes, preferential signals, and fewer but more distinct stops. The Federal Transit Administration's (FTA) Bus Rapid Transit (BRT) program is aimed at upgrading bus

Vukan R. Vuchic

77

Bus travel safety - A travel chain perspective  

Microsoft Academic Search

The injury risk for bus passengers is low compared to car users. However, bus passengers also run the risk of sustaining injuries as vulnerable road users: as pedestrians or cyclists to and from the bus stop. Among vulnerable road users, seniors are a particularly important group. Hitherto, injury data have mainly been based on police-reported accidents. These accidents reveal bus

Monica Berntman; Anders Wretstrand; Bengt Holmberg

2010-01-01

78

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

79

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

80

LR-algorithm: concurrent operations on priority queues  

Microsoft Academic Search

The heap representation of priority queues is one of the most widely used methods. However, the conventional implementation tends to be inadequate for parallel applications. The paper proposes a new method, the LA-algorithm, which allows concurrent insertions on priority queues. In contrast to the conventional heap implementation, the LR-algorithm directs any two consecutive insertion requests to two different subtrees and

Rassul Ayani

1990-01-01

81

Active queue management based on particle swarm optimization PID algorithm  

Microsoft Academic Search

This paper proposes an algorithm for improving adaptation and coefficients adjustment of active queue management by particle swarm optimization PID algorithm. In this algorithm, swarm particle optimization is combined with PID algorithm, which can settle the coefficients adjustment online in PID and can adapt the variation of network traffic, so this algorithm can effectively fulfill active queue management. The simulation

Tao Wei; Shun-yi Zhang

2008-01-01

82

Optimization of active queue management based on proportional control system  

Microsoft Academic Search

This paper shows the design and performance of an AQM (Active Queue Management) enabled router. The design is based on a classical proportional control system. The appli- cation of such a router is to enhance streaming media over IP performance by avoiding bursty packet drop situations, control the router queue delay, and balancing packet drop, delay, and link utilization. The

Arne Lie; Ole M. Aamo; Leif Arne Rønningen

2004-01-01

83

Improved Active Queue Management Algorithm for High Performance Networks  

Microsoft Academic Search

On the problem of some active queue management (AQM) algorithms having long time adjustment and being not able to stabilize the queue length to the desired one in dynamic network environment. An improved AQM algorithm for high performance networks based on integral-separated PID and incomplete-derivative PID is proposed. Its performance is evaluated by simulation experiments, which demonstrate that the proposed

Long Ge; Jinsheng Sun; Zhiquan Wang

2009-01-01

84

Lightweight Active Router-Queue Management for Multimedia Networking  

Microsoft Academic Search

The Internet research community is promoting active queue management in routers as a proactive means of addressing congestion in the Internet. Active queue management mechanisms such as Random Early Detection (RED) work well for TCP flows but can fail in the presence of unresponsive UDP flows. Recent proposals extend RED to strongly favor TCP and TCP-like flows and to actively

Mark Parris; Kevin Jeffay; F. Donelson Smith

1999-01-01

85

Fast simulation of rare events in queueing and reliability models  

Microsoft Academic Search

This paper surveys efficient techniques for estimating, via simulation, the probabilities of certain rare events in queueing and reliability models. The rare events of interest are long waiting times or buffer overflows in queueing systems, and system failure events in reliability models of highly dependable computing systems. The general approach to speeding up such simulations is to accelerate the occurrence

Philip Heidelberger

1995-01-01

86

Fast Simulation of Rare Events in Queueing and Reliability Models  

Microsoft Academic Search

This paper surveys efficient techniques for estimating, via simulation, the probabilities of certain rare events in queueing and reliability models. The rare events of interest are long waiting times or buffer overflows in queueing systems, and system failure events in reliability models of highly dependable computing systems. The general approach to speeding up such simulations is to accelerate the occurrence

Philip Heidelberger

1993-01-01

87

Monitoring Queues without Observing Them: A New Technology for Industry.  

National Technical Information Service (NTIS)

The Queue Inference Engine (QIE), is analyzed. The QIE represents a new, data-oriented way to deduce queue behavior in practice by using only customer transactional data - the time of service initiation and service completion for each customer served. In ...

M. F. Cahn R. C. Larson

1990-01-01

88

Stochastic Estimation and Control of Queues within a Computer Network.  

National Technical Information Service (NTIS)

An extended Kalman filter is used to estimate size and packet arrival rate of network queues. These estimates are used by a LQG steady state linear perturbation PI controller to regulate queue size within a computer network. This paper presents the deriva...

N. C. Stuckey

2007-01-01

89

A block queueing system for slow moving traffic  

Microsoft Academic Search

A common cause of pollution and waste in urban areas is facilities which provide a continuous slow service for motor vehicles. As demand approaches supply, queues can develop and large numbers of engines can often be idling. Typical examples are car park entrances and drive through fast food outlets. This paper proposes a block queueing system to alleviate the problem

Mark Dougherty

1997-01-01

90

Asymptotic Analysis of Multiclass Closed Queueing Networks: Multiple Bottlenecks  

Microsoft Academic Search

Asymptotic expressions for the values of throughputs, utilizations, mean queue lengths, and mean cycle times are derived for multiclass product-form queueing networks with load independent servers, where different (sets of) stations may behave as bottlenecks when different population mixes load the network. The space of possible population mixes is shown to be partitioned into sectors within which several stations may

Gianfranco Balbo; Giuseppe Serazzi

1997-01-01

91

STEADY-STATE PROBABILITIES FOR SOME QUEUEING SYSTEMS: I  

Microsoft Academic Search

Two routing rules for a queuing system of two stations are considered as alternative models for modeling a queuing network. These routing rules allow customers to switch queues under certain server and other resource availability conditions, either external to the system upon arrival to the network, or internal to the system after arrival to a primary queue. Under the assumption

Mahmoud Abdel; Moaty Hussain

92

Walking School Bus Networks: A \\  

Microsoft Academic Search

Summary A Walking School Bus (WSB) is an alternative method for children to travel to and from school. Adult volunteers walk a set route to school, collecting children from designated stops along the way. In 2000, we trialed WSB \\

Carolyn O'Fallon; Charles Sullivan; Paul Cottam

93

Sheffield Study: Bus Boarding Survey.  

National Technical Information Service (NTIS)

The effectiveness was studied of two bus entrance modifications designed to facilitate boarding for the elderly and physically handicapped. One modification was a split front step for double deck buses. The other was to enable single deck buses to kneel. ...

P. R. Oxley

1983-01-01

94

Sheffield Study: Bus Users' Survey.  

National Technical Information Service (NTIS)

The effectiveness was studied of two bus entrance modifications designed to facilitate boarding for the elderly and ambulant physically handicapped. One modification was a split step for double deck buses. The other was to enable single deck buses to knee...

M. Benwell

1983-01-01

95

Feeder bus route design problem  

SciTech Connect

The US transit industry is in a financial crisis, caused primarily by the rising operating cost and shrinking resources. Among the deficit-reducing strategies that have been proposed, a better integrated transit system has significant advantages in that it offers the possibility of simultaneously reducing cost and increasing revenue. This research develops an optimization-based methodology for the design of an integrated feeder bus/rail transit system. The proposed methodology includes two types of models, an analytic model and a network model. The study defines the Feeder Bus Route Design Problem (FBRDP) as that of locating bus routes and bus stops as well as determining the service characteristics of a feeder bus system, designed to access an existing rail system. The proposed analytic model provides approximate values for the optimal route density, operating headway and bus stop spacing. Within the network approach, the author considers demand with a single (many-to-one) and with multiple (many-to-many) destinations. The network optimization models for the FBRDP are routing-type models that cannot be solved exactly and need to be solved heuristically. A two-phase heuristic is developed that can be viewed as a generalization of the sequential-savings approach to vehicle routing.

Kuah, G.K.

1986-01-01

96

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

Federal Register 2010, 2011, 2012, 2013

...TRANSPORTATION Federal Transit Administration Section 5309 Bus and Bus Facilities Livability...Grants AGENCY: Federal Transit Administration (FTA...information on the Bus Livability Program...Sledge, Office of Transit Programs,...

2010-02-04

97

Queueing phase transition: theory of translation  

PubMed Central

We study the current of particles on a lattice, where to each site a different hopping probability has been associated and the particles can move only in one direction. We show that the queueing of the particles behind a slow site can lead to a first-order phase transition, and derive analytical expressions for the configuration of slow sites for this to happen. We apply this stochastic model to describe the translation of mRNAs. We show that the first-order phase transition, uncovered in this work, is the process responsible for the classification of the proteins having different biological functions.

Romano, M. Carmen; Thiel, Marco; Stansfield, Ian; Grebogi, Celso

2013-01-01

98

Queueing analysis of finite buffer token networks  

Microsoft Academic Search

This paper introduces analytic models for evaluating demand assignment protocols in realistic finite buffer\\/finite station network configurations. We present a solution for implicit and explicit token passing systems enabling us to model local area networks, such as Token Bus. We provide, for the first time, a tractable approximate solution by using an approach based on restricted occupancy urn models. The

Aura Ganz; Imrich Chlamtac

1988-01-01

99

On Asymptotic Optimality of Dual Scheduling Algorithm In A Generalized Switch  

Microsoft Academic Search

Generalized switch is a model of a queueing system where parallel servers are interdependent and have time-varying service capabilities. This paper considers the dual scheduling algorithm that uses rate control and queue-length based scheduling to allocate resources for a generalized switch. We consider a saturated system in which each user has in£nite amount of data to be served. We prove

Lijun Chen; Steven H. Low; John C. Doyle

2006-01-01

100

Queue-length synchronization in communication networks  

NASA Astrophysics Data System (ADS)

We study the synchronization in the context of network traffic on a 2-d communication network with local clustering and geographic separations. The network consists of nodes and randomly distributed hubs where the top five hubs ranked according to their coefficient of betweenness centrality (CBC) are connected by random assortative and gradient mechanisms. For multiple message traffic, messages can trap at the high CBC hubs, and congestion can build up on the network with long queues at the congested hubs. The queue lengths are seen to synchronize in the congested phase. Both complete and phase synchronization are seen, between pairs of hubs. In the decongested phase, the pairs start clearing and synchronization is lost. A cascading master-slave relation is seen between the hubs, with the slower hubs (which are slow to decongest) driving the faster ones. These are usually the hubs of high CBC. Similar results are seen for traffic of constant density. Total synchronization between the hubs of high CBC is also seen in the congested regime. Similar behavior is seen for traffic on a network constructed using the Waxman random topology generator. We also demonstrate the existence of phase synchronization in real internet traffic data.

Mukherjee, Satyam; Gupte, Neelima

2009-05-01

101

Critical behavior of the exclusive queueing process  

NASA Astrophysics Data System (ADS)

The exclusive queueing process (EQP) is a generalization of the classical M/M/1 queue. It is equivalent to a totally asymmetric exclusion process (TASEP) of varying length. Here we consider two discrete-time versions of the EQP with parallel and backward-sequential update rules. The phase diagram (with respect to the arrival probability ? and the service probability ?) is divided into two phases corresponding to divergence and convergence of the system length. We investigate the behavior on the critical line separating these phases. For both update rules, we find diffusive behavior for small service probability (\\beta < \\beta_c) . However, for \\beta>\\beta_c it becomes sub-diffusive and nonuniversal: the critical exponents characterizing the divergence of the system length and the number of customers are found to depend on the update rule. For the backward-update case, they also depend on the hopping parameter p, and remain finite when p is large, indicating a first-order transition.

Arita, Chikashi; Schadschneider, Andreas

2013-11-01

102

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

103

Some Questions to Ask about Your School Bus Program.  

ERIC Educational Resources Information Center

Questions based on observations of a Chicago (Illinois) school bus program deal with driver capability, procedures for bus evacuation in an emergency, bus comfort for passengers, safety, fuel efficiency, and creative use of students' bus time. (MLF)

Balousek, Marvin

1980-01-01

104

Standard NIM Digital Bus (NIM/GPIB).  

National Technical Information Service (NTIS)

This document defines a standard digital data bus for NIM instruments as defined in Publication TID-20893 issued by the United States Atomic Energy Commission (now under the US Department of Energy). It utilizes the General Purpose Instrumentation Bus (GP...

1983-01-01

105

Project Super Bus: High-Capacity Bus Conceptual Design Study.  

National Technical Information Service (NTIS)

The purpose of the study was to determine the technical criteria for high-capacity transit buses for U.S. operation. Principal emphasis was placed on the articulated bus concept, because the maneuverability of articulated buses makes them suitable for ser...

1974-01-01

106

Analysis of a Non-Trivial Queueing Network.  

National Technical Information Service (NTIS)

In studying complex queueing networks, one generally seeks to employ exact analytic solutions to reduce burden on computational resources. Barring the existence of an exact solution, the alternatives include approximation techniques and simulation. Approx...

K. S. Bellamy

1999-01-01

107

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.

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

2014-01-01

108

Massively Parallel Simulation and Optimization of Queueing Networks.  

National Technical Information Service (NTIS)

We simulate several variants of a class of queueing networks corresponding to different system parameter values or operating policies - simultaneously. One clock mechanism is used to drive all the variants. This clock synchronizes the system trajectories ...

P. Vakili E. Lau

1992-01-01

109

Transient Analysis of Markov-Fluid-Driven Queues.  

National Technical Information Service (NTIS)

In this paper we study two transient characteristics of a Markov-fluid-driven queue, i.e., the busy period and the covariance function of the workload process. Both metrics are captured in terms of their Laplace transforms.

A. Es-Saghouani M. R. H. Mandjes

2008-01-01

110

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

111

A Bus Passengers' Seating Preference Model  

Microsoft Academic Search

We present an agent-based model of a public bus where some passengers board and exit at every stop. Agents are the passengers characterized by their ethnicity, age group and cultural backgrounds and respective preferences for seats in the bus. Different scenarios are set up whereby the bus moves in various parts of the city, which maybe segregated residentially, university campuses,

Shah Jamal Alam; Bogdan Werth

112

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

113

School Bus Alert System Reduces Delays.  

ERIC Educational Resources Information Center

The school bus alert monitor is a computerized school bus alert and warning sytem that notifies parents of school bus arrival via radio frequency technology. The system also has been shown to enhance the self esteem of disabled transportation users. (CL)

Pleasnick, Stephen G.

1985-01-01

114

A Symmetrical Exponential Open Queue Network with Blocking and Feedback  

Microsoft Academic Search

The exponential open queue network model studied here consists of n symmetrical queues in parallel served by independent first-level servers in tandem with a second-level server. Blocking of the flow of units through a first-level server occurs each time the server completes a service. The server remains blocked until its blocking unit completes its service at the second-level server. An

Harry G. Perros

1981-01-01

115

On the maximum queue length in the supermarket model  

Microsoft Academic Search

There are $n$ queues, each with a single server. Customers arrive in a Poisson process at rate $\\\\lambda n$, where $0<\\\\lambda<1$. Upon arrival each customer selects $d\\\\geq2$ servers uniformly at random, and joins the queue at a least-loaded server among those chosen. Service times are independent exponentially distributed random variables with mean 1. We show that the system is rapidly

Malwina J. Luczak; Colin McDiarmid

2006-01-01

116

Forecasting Bus Transit Operating Costs.  

National Technical Information Service (NTIS)

The study deals with forecasting the cost of operating bus transit systems in U.S. cities. The primary objective is to develop a practical forecasting model for use by transit planners, i.e., a tool that will provide quantitative estimates (forecasts) of ...

H. G. Wilson

1975-01-01

117

Bus Boarding and Alighting Times.  

National Technical Information Service (NTIS)

Large-scale conversion of buses to one-man-operation is currently being undertaken by many operators. The report considers in detail the stop-time characteristics of a variety of different bus types, both one-and two-man-operated, and tries to identify so...

M. A. Cundill P. F. Watts

1973-01-01

118

Memory card address bus design  

Microsoft Academic Search

The interaction of signal line impedance, crosstalk, chip capacitive loading and driver circuit output impedance on the operation of a memory address bus is demonstrated. The ASTAP circuit simulation program is used for detailed studies. The results of three parallel address lines connected to memory chips for unterminated far ends are discussed. Signal-line impedance decreases when adjacent lines are introduced.

Debra A. Gernhart; Chi Shih Chang; Keith K. T. Ho

1990-01-01

119

On the convergence of traffic measurement and queueing analysis: a statistical-matching and queueing (SMAQ) tool  

Microsoft Academic Search

The analytical tool developed in this paper provides a general solution technique for integration of traffic measurement and queueing analysis. The frequency-domain approach is used to combine the advanced techniques in two areas: signal processing and queueing analysis. Essentially, signal processing techniques are used to obtain the steady-state and second-order statistics of a traffic stream. We propose a new programming

San-qi Li; Chia-lin Hwang

1997-01-01

120

Unslotted 1- and p(i)-persistent CSMA-CD protocols for fiber optic bus networks  

NASA Astrophysics Data System (ADS)

We analyze the performance of the unslotted 1-persistent carrier sense multiple access with collision detection (CSMA-CD) protocol for fiber optic bus networks with a finite number of stations M, each of which has an infinite storage buffer for storing packets with its length fixed or exponentially distributed. Treating the bus network as an M-class priority queueing system with a preemptive-repeat-identical retransmission strategy, we show numerically that this 1-persistent retransmission strategy provides better delay-throughput performance than the non-persistent one. To satisfy the fairness of equal delays among stations in the bus network, we next present the unslotted p(sub i)-persistent CSMA-CD protocol. Under this protocol, the first packet arriving at station i is forced to enter into the backoff procedure with the probability of (1 - p(sub i)). After backoffs, transmission begins until the station becomes empty. We determine the persistent probability p(sub i) and show that the delay-throughput performance of the p(sub i)-persistent strategy is better than that of the 1-persistent one, and further it is robust for any packet lengths. Simulation results are presented to verify the analytical results.

Yoon, Chong Ho; Un, Chong Kwan

1994-02-01

121

Electrical system architecture having high voltage bus  

SciTech Connect

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

Hoff, Brian Douglas (East Peoria, IL); Akasam, Sivaprasad (Peoria, IL)

2011-03-22

122

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

123

BUS high current battery model  

NASA Astrophysics Data System (ADS)

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 current in a few seconds followed by a 5 s test. A series of tests were performed to determine the driving voltage and ESR of the batteries for discharge times from 2 to 10 s and current levels from 500 to 2,500 A. A model for voltage and ESR were obtained from these tests. The methods used and sample data from the tests are presented. The main factors affecting battery voltage and ESR are discussed.

Kajs, J. P.; Zowarka, R. C.

1993-01-01

124

Variable Length Virtual Output Queue Based Fuzzy Adaptive RED for Congestion Control at Routers  

Microsoft Academic Search

\\u000a Internet routers play an important role during the time of network congestion. All the Internet routers have some buffer at\\u000a input and output ports, which hold the packets at the time of congestion. Many queue management algorithms have been proposed\\u000a but they focus on fixed queue limit. Recognizing the fact that active queue management algorithms have fixed maximum queue\\u000a limit,

Pramod Kumar Singh; Santosh Kumar Gupta

125

Bayesian analysis of Er\\/ M\\/1 and Er\\/ M\\/ c queues  

Microsoft Academic Search

Bayesian inference and prediction tasks for Er\\/M\\/1 and Er\\/M\\/c queues are undertaken. Equilibrium probabilities of the queue size and waiting time distributions are estimated using conditional Monte-Carlo simulation methods. We illustrate that some standard queueing measures do not exist when independent priors are used for the arrival and service rates of a G\\/M\\/1 queue.

M. P. Wiper

1998-01-01

126

Permutable Queue as a 1-in-N-out Message Router  

Microsoft Academic Search

The basic queue is a first-in-first-out linear data structure (software component). It can be considered as a communication device with one input port and one output port. In the paper, we investigate the behavior of an extended queue that has one input channel and multiple output channels. An enter-queue command enters a data item into the queue as does an

Gongzhu Hu; Mount Pleasant

2007-01-01

127

Bus-coupled microresonator lasers  

NASA Astrophysics Data System (ADS)

Microresonators are of considerable interest in wavelength division multiplexing (WDM) applications due to their small feature size and versatile functionality. When combined with other high-Q passive and active elements connected through a common bus line, microresonator lasers will enable the fabrication of sophisticated photonic integrated circuits (PICs) that take full advantage of compact chip layouts. Circular microresonator lasers are attractive sources for PICs because of their cleavage-free cavity and excellent wavelength selectivity. We have demonstrated an InP/InGaAsP microdisk resonator laser, where a high-Q microdisk lasing mode is vertically coupled out through a straight bus waveguide. The vertically coupled design is realized by using wafer-boding techniques. By connecting multiple microdisk lasers through a common output bus line, we have demonstrated an 8-channel laser arrays with 1.6 nm (200 GHz) spectral channel spacing. The channel spacing is achieved by varying the disk resonator radii from 10.6 to 10.95 mm. Typical threshold current of ~ 7 mA is observed under CW lasing operation near 1510 nm. In this presentation we will discuss the operating characteristics of microresonator lasers and the use of resonators in laser cavities as wavelength selection and stabilization elements.

Choi, Seung-June; Peng, Zhen; Yang, Qi; Choi, Sang Jun; Dapkus, P. D.

2005-04-01

128

Data association in target tracking using priority queues  

NASA Astrophysics Data System (ADS)

Data association is one of the main components of target tracking. While, in its simplest form, data association links a list of tracks to a list of measurements or links two lists of measurements (2-D association), the more complex problem involves assignment of multiple number of such lists (S-D association where S ? 3). In target tracking, the presence of false detections (false alarms) and the absence of detections from some targets (missed detections) complicate the problem of data association further. In this work, we explore the possibility of applying track ordering in priority queues to solve the association problem more efficiently. The basic component of our algorithm is to form priority queues by permutations of the tracks. Each queue is served on a first-come-first-served basis, i.e., each track is assigned to the best measurement available based on its turn in the queue. It can be shown that the best solution to the 2-D problem can be obtained from one of these queues. However, the solution is computationally expensive even for a moderate number of targets. In this paper we show that due to redundancy only a small fraction of the total number of permutations is required to be evaluated to obtain the best solution.

Sinha, A.; Kirubarajan, T.; Farooq, M.

2005-09-01

129

NEWQUE with Per-flow Scheduling: Performance improvement of Active Queue Management algorithm  

Microsoft Academic Search

In order to design the congestion control scheme in the routers, an Active Queue Management (AQM) is proposed. This is used to control congestion at the router, where packets are dropped before queue becomes full. A new framework of AQM, namely NEWQUE with Per-flow Scheduling (PerNEWQUE) active queue management algorithm supporting explicit congestion notification (ECN), is proposed by extending scheduling

V. Santhi; A. M. Natarajan

2010-01-01

130

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

131

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 the detec- tion of network congestion, the notification of such occurre nces 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

132

Throughput analysis and optimal design of Banyan switches with bypass queues  

NASA Astrophysics Data System (ADS)

A Banyan switch with bypass queue can overcome the problem of head of line blocking. This paper presents the throughput analysis for such a switch and the optimal window size for the bypass queue is also obtained. Moreover, to reduce the effect of the internal blocking and to increase the throughput, a parallel Banyan switch with bypass queue is also discussed and analyzed.

Su, Yo-Song; Huang, Jau-Hsiung

1994-10-01

133

Aggregate traffic performance with active queue management and drop from tail  

Microsoft Academic Search

Active queue management (AQM) refers to a family of packet dropping mechanisms for router queues that has been proposed to support end-to-end congestion control mechanisms in the Internet. In this paper, we examine the performance of AQM mechanisms by varying two parameters: the queue size and the dropping function. AQM flavors considered include \\

Gianluca Iannaccone; Martin May; Christophe Diot

2001-01-01

134

Aggregate Traffic Performance with Active Queue Management and Drop from Tail  

Microsoft Academic Search

Active queue management (AQM) refers to a family of packet drop- ping mechanisms for router queues that has been proposed to sup- port end-to-end congestion control mechanisms in the Internet. In this paper, we examine the performance of AQM mechanisms by varying two parameters: the queue size and the dropping function. AQM flavors considered include \\

Gianluca Iannaccone; Sprint ATL; Adrian Court; Burlingame CA; Martin May; Christophe Diot

135

Queues with Dependency Between Interarrival and Service Times Using Mixtures of Bivariates  

Microsoft Academic Search

We analyze queueing models where the joint density of the interarrival time and the service time is described by a mixture of joint densities. These models occur naturally in multiclass populations serviced by a single server through a single queue. Other motivations for this model are to model the dependency between the interarrival and service times and consider queue control

Srikanth K. Iyer; D. Manjunath

2006-01-01

136

A discrimination frequency based queueing fairness measure with regard to job seniority and service requirement  

Microsoft Academic Search

Queueing theory has dealt comprehensively with waiting times, throughput, or related properties. Another important issue, which is fair queueing, has been neglected for a long time and has received reasonable attention only very recently. As of today there are no generally accepted definitions and measures although some have been proposed. It has been recognized that measuring fairness in queues suffers

Werner Sandmann

2005-01-01

137

A Novel Bus Lane Enforcement System with Vehicular Sensor Networks  

Microsoft Academic Search

Bus lane enforcement system aims to monitor illegal utilization of bus lane by non-permitted vehicles (violator). However, Road-side system leads to considerable infrastructure cost while bus mounted system has limited surveillance coverage. In this paper, we consider an interesting problem in bus mounted system: how to improve the surveillance coverage of bus mounted system without additional infrastructure cost? In other

Xu Li; Ting Cao; Hongyu Huang; Minglu Li; Wei Shu; Min-You Wu

2010-01-01

138

Bus travel time prediction model with ? - support vector regression  

Microsoft Academic Search

Bus travel time prediction is a vital part for both bus operation optimizing system and information service system. This paper reviews existing bus travel time prediction models and analyzes the strengths and weaknesses of each model. A bus travel time prediction model based on nu - Support Vector Regression is proposed, which uses the departure time of bus from origin

Jing-nan Wang; Xu-mei Chen; Shu-xia Guo

2009-01-01

139

76 FR 68819 - State of Good Repair Bus and Bus Facilities Discretionary Program Funds  

Federal Register 2010, 2011, 2012, 2013

...For general program information on the Bus and Bus Facilities program contact Samuel Snead, Office of Program Management, at (202) 366-1089, email: Samuel.Snead@dot.gov, or Kimberly Sledge, Office of Program Management, at...

2011-11-07

140

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

141

Characteristics of the Unexpected Message Queue of MPI applications  

SciTech Connect

High Performance Computing systems are used on a regular basis to run a myriad of application codes, yet a surprising dearth of information exists with respect to communications characteristics. Even less information is available on the low-level communication libraries, such as the length of MPI Unexpected Message Queues (UMQs) and the length of time such messages spend in these queues. Such information is vital to developing appropriate strategies for handling such data at the library and system level. In this paper we present data on the communication characteristics of three applications GTC, LSMS, and S3D. We present data on the size of their UMQ, the time spend searching the UMQ and the length of time such messages spend in these queues. We find that for the particular inputs used, these applications have widely varying characteristics with regard to UMQ length and show patterns for specific applications which persist over various scales.

Keller, Rainer [Universitat Stuttgart; Graham, Richard L [ORNL

2010-01-01

142

Factors affecting the safety performance of bus companies—The experience of Taiwan bus deregulation  

Microsoft Academic Search

This study was undertaken to explore the factors affecting the safety performance of bus companies in Taiwan. A conceptual framework was developed based on the theory of organizational accidents. Environmental and organizational factors were assumed to determine the safety performance of bus companies. Since the deregulation of intercity passenger transportation in 1995 the bus transportation industry in Taiwan has been

Hsin-Li Chang; Chun-Chih Yeh

2005-01-01

143

49 CFR 605.19 - Approval of school bus operations.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Approval of school bus operations. 605.19 Section 605.19...TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SCHOOL BUS OPERATIONS School Bus Agreements § 605.19 Approval of...

2013-10-01

144

49 CFR 605.19 - Approval of school bus operations.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Approval of school bus operations. 605.19 Section 605...Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SCHOOL BUS OPERATIONS School Bus Agreements § 605.19 Approval...

2009-10-01

145

49 CFR 605.19 - Approval of school bus operations.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Approval of school bus operations. 605.19 Section 605...Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SCHOOL BUS OPERATIONS School Bus Agreements § 605.19 Approval...

2010-10-01

146

Open high speed bus for microcomputer system  

US Patent & Trademark Office Database

An open high-speed local system bus for a microcomputer system which is decoupled from I/O and provides a consistent interface to the CPU subsystem, memory subsystem, graphics subsystem and peripheral subsystem. The local system bus supports discrete and burst transactions, pipelining in both the transactions, multiple microprocessor and distributed interrupts.

1996-05-14

147

California's Bus Driver's Training Course. Instructor's Manual.  

ERIC Educational Resources Information Center

This instructor's manual was designed to help graduates of the California Bus Driver Instructor Course provide effective instruction to school bus driver trainees. It contains enough material for 20-30 hours of classroom training. The information is organized in 12 instructional units that cover the following topics: introduction to the course;…

California State Dept. of Education, Sacramento.

148

BUS RAPID TRANSIT: SYNTHESIS OF CASE STUDIES  

Microsoft Academic Search

Bus rapid transit systems have grown in popularity in recent years. Spurred by federal initiatives, the spiraling cost of rail transit, and market realities, a growing number of cities have installed or are planning bus rapid transit (BRT). There is a synthesis of current experience, drawing on ongoing research conducted in a project for the Transit Cooperative Research Program (TCRP).

Herbert S Levinson; Samuel Zimmerman; Jennifer Clinger; James Gast

2003-01-01

149

The demand performance of bus rapid transit  

Microsoft Academic Search

This article uses a trip attribute approach to examine the relative passenger attractiveness of Bus Rapid Transit (BRT) systems compared to other transit modes. It examines how passengers value trip attributes for on-street bus, BRT, and light rail and heavy rail systems in passenger behavior research. Empirical data is presented which suggests that passengers value trip attributes for BRT and

Graham Currie

2005-01-01

150

Distributed holding control of bus transit operations  

Microsoft Academic Search

A distributed control approach based on multi-agent negotiation is presented to address the bus-holding problem. The negotiation between a bus agent and a stop agent is conducted based on marginal cost calculations. Optimality conditions are discussed in the paper. Finally, comparison between the negotiation algorithm and commonly used strategies are done through simulations, which verify the robustness of our negotiation

Jiamin Zhao; Maged Dessouky; Satish Bukkapatnam

2001-01-01

151

Institutional Aspects of Bus Rapid Transit Operation  

Microsoft Academic Search

This report presents the findings of its investigation of institutional aspects of bus rapid transit (BRT) through both a macroscopic examination, a survey of members of the U.S. Bus Rapid Transit Consortium and several Canadian transit properties, and a more focused site-specific examination of three California BRT systems. The macroscopic examination resulted from a literature review, project team brainstorming meetings,

Mark A. Miller; Stephen M. Buckley

2001-01-01

152

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

153

TRIP COSTS ANALYSIS OF BUS RAPID TRANSIT  

Microsoft Academic Search

Bus rapid transit (BRT) is a kind of public transportation with the characteristics of high quality as rail system and flexibility as bus operation. The development of BRT system is a cost-effective approach to improve traffic congestion and promote public transit without increasing financial burdens. In this study, we established trip cost models in the view points of social cost

Shyue-Koong Chang; Yu-Jian Guo

2005-01-01

154

Productivity measurement in the urban bus sector  

Microsoft Academic Search

This paper investigates the relative performance of urban bus operators in Australia. An index of gross total factor productivity (GTFP) for each operator is developed and decomposed to identify the sources of variation across operators, such as the role of different institutional and regulatory ‘constraints’ on relative performance. Data has been compiled from a sample of private bus operations in

David A Hensher; Rhonda Daniels

1995-01-01

155

An analytic investigation of optimal bus size  

Microsoft Academic Search

The use of smaller buses offers passengers a better service frequency for a given service capacity, but costs more to operate per seat provided. Within this trade-off there is an optimal bus size which maximises social benefit. A mathematical model is described which can be solved analytically to provide an explicit relationship between optimal bus size and factors such as

R. H. Oldfield; P. H. Bly

1988-01-01

156

Dynamically Configured ? ? ? ?-opt Heuristics for Bus Scheduling  

Microsoft Academic Search

Bus scheduling is a complex combinatorial optimization problem (3), (10). The op- erations planning and scheduling process starts off with the designing of a timetable of trips that have to be served by buses. Each trip has a starting time\\/location and a destination time\\/location. Bus scheduling involves assigning a set of trips to a set of buses such that: 1.

Prapa Rattadilok; Raymond S K Kwan

157

Modelling Urban Bus Service and Passenger Reliability  

Microsoft Academic Search

This paper investigates some of the measures used to assess reliability of an urban bus network using a dynamic microsimulation model framework. The framework incorporates models of bus operation, passenger arrival and boarding for buses within a network model of general traffic. It therefore allows explicit modelling of the interactions among cars, buses and passengers and of their effect on

Ronghui Liu; Shalini Sinha

158

Experiencing BLISS when becoming a bus passenger  

Microsoft Academic Search

This paper understands the design of bus information panels as rooted in a landscape of human experience. It turns the mundane activity of waiting at a bus stop into a deeply problematic space of emotion and volition by understanding the dialogic relationship between human and technology. It does this by developing a novel approach to interaction design, which combines a

Darren J. Reed; Peter C. Wright

2006-01-01

159

Neurosimulation modeling of a scheduled bus route  

SciTech Connect

In a densely built-up urban society, operators of public bus services are faced with the recurrent problem of providing timely and reliable service. Wile they have no control over dynamically changing extraneous factors (such as passenger loads or road conditions) that may suddenly degrade the quality of the service provided, it is nonetheless desirable for management to study the extent to which these factors affect their business, and what measures, if any, can be adopted to neutralize them. This paper discusses how a simulation model of a bus route, embellished by a neural network, was created to model the historical pattern of the inputs (namely, passenger loads and road conditions) that affect the overall scheduled terminus-to-terminus time. Thus, in a case study of a bus route running from a suburb to the city center, it was found that the neurosimulation model could predict the cumulative terminus-to-terminus times better than a conventional simulation model could. A software module, embedded into the neurosimulation model for the purposes of speed regulation, was able to minimize the deviation of the bus service from schedule. When intentional delays were further introduced into the bus route, it was discovered that the speed regulator was more effective the longer the delay, and the further the bus traveled into the bus route. There is potential in applying neural computing in a dynamic bus scheduling problem such as the one discussed here.

Lee, S.G.; Khoo, L.P. [Nanyang Technological Univ. (Singapore). School of Mechanical and Production Engineering

1997-05-01

160

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

161

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

162

Design Considerations for Supporting TCP with Per-Flow Queueing  

Microsoft Academic Search

n this pape~ we investigate the extent to which fair queueing (and its variants), in conjunction with appropriately tailored buffer management schemes, can be used to achieve the following goals for TCP trajic: J) alleviate the inherent unfairness of TCP towards connections with long round-trip times, 2) provide isolation when connections using dl~erent TCP versions share a bottleneck link, 3)

Bernhard Suter; T. V. Lakshman; Dimitrios Stiliadis; Abhijit K. Choudhury

1998-01-01

163

Trading Rate for Balanced Queue Lengths for Network Delay Minimization  

Microsoft Academic Search

We consider a communication channel with two transmitters and one receiver, with an underlying rate region which is approximated as a general pentagon. Different from the Gaussian multiple access channel (MAC) capacity region, the sum-rate on the dominant face of this pentagon is not a constant. We allocate rates from this rate region to users according to their current queue

Jing Yang; Sennur Ulukus

2011-01-01

164

The effects of active queue management on web performance  

Microsoft Academic Search

We present an empirical study of the effects of active queue management (AQM) on the distribution of response times experienced by a population of web users. Three prominent AQM schemes are considered: the Proportional Integrator (PI) controller, the Random Exponential Marking (REM) controller, and Adaptive Random Early Detection (ARED). The effects of these AQM schemes were studied alone and in

Long Le; Jay Aikat; Kevin Jeffay; F. Donelson Smith

2003-01-01

165

Vertical dimensioning: A novel DRR implementation for efficient fair queueing  

Microsoft Academic Search

Fair bandwidth allocation is an important mechanism for traffic management in the Internet. Round robin schedulers, such as Deficit Round Robin (DRR), are well-suited for implementing fair queueing in multi-Gbps routers, as they schedule packets in constant time regardless of the total number of active flows. The main drawback of these schemes, however, lies in the maintenance of per flow

Spiridon Bakiras; Feng Wang; Dimitris Papadias; Mounir Hamdi

2008-01-01

166

Speed up the Responsiveness of Active Queue Management System  

Microsoft Academic Search

SUMMARY As an enhancement mechanism for the end-to- end congestion control, AQM (Active Queue Management) can keep smaller queuing delay and higher throughput by purpose- fully dropping the packets at the intermediate nodes. Compar- ing with RED algorithm, although the PI (Proportional-Integral) controller for AQM designed by C. Hollot improves the sta- bility, it seems unscientific to tune the controller

Fengyuan REN; Chuang LIN

2003-01-01

167

Active Queue Management Based on Single Neural Adaptive PID Algorithm  

Microsoft Academic Search

This paper proposes an algorithm for improving adaptation and parameters adjustment of active queue management by using single neural adaptive PID algorithm. In this algorithm, single neural is combined with PID algorithm, which can settle the parameters adjustment in PID and can adapt the variation of network parameters by changing the weights of the single neural online, so this algorithm

Wei Tao; Zhang Shun-yi

2008-01-01

168

Performance Analysis of Active Queue Management Schemes for IP Network  

Microsoft Academic Search

Active Queue Management schemes have evolved over time and continue to do so. In this paper, we present a comprehensive survey of AQM schemes for IP network. Its purpose is to identify the basic approaches that have been proposed and classify them according to the design goals and performance issues of AQM schemes. The results from several performance evaluation such

Jahwan Koo; Seong-jin Ahn; Jin-wook Chung

2004-01-01

169

Stable Queue Management for Supporting TCP Flows over Wireless Networks  

Microsoft Academic Search

Congestion control for wireless networks is much more challenging than that for wired networks, due to the limited wireless spectrum and severe impairments of wireless medium which suffer from time-varying fading, shadowing, interference, etc. Although the stability of the Internet using TCP congestion control and active queue management (AQM) schemes has been extensively investigated, effective congestion control for wireless networks

Hiroaki Mukaidani; Lin Cai; Xuemin Shen

2011-01-01

170

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

171

Single Server Queue with Mixed Types of Interruptions.  

National Technical Information Service (NTIS)

The singer server M/G/1 queue subject to Poisson interruptions has many useful applications in computer systems modeling. The interruptions are usually characterized by their type of service-preemption discipline. This paper deals with this model in its m...

V. F. Nicola

1985-01-01

172

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

173

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

174

A state-queueing model of thermostatically controlled appliances  

Microsoft Academic Search

This paper develops a state-queueing model to analyze the price response of aggregated loads consisting of thermostatically controlled appliances (TCAs). Assuming a perfectly diversified load before the price response, we show that TCA setpoint changes in response to the market price will result in a redistribution of TCAs in on\\/off states and therefore change the probabilities for a unit to

Ning Lu; David P. Chassin

2004-01-01

175

Performance bounds for queueing networks and scheduling policies  

Microsoft Academic Search

Except for the class of queueing networks and scheduling policies admitting a product form solution for the steady-state distribution, little is known about the performance of such systems. For example, if the priority of a part depends on its class (e.g., the buffer that the part is located in), then there are no existing results on performance, or even stability.

Sunil Kumar; P. R. Kumar

1994-01-01

176

Analysis of Queues with Autocorrelated Times to Failures  

Microsoft Academic Search

In this paper, we study process completion time analysis and propose an accurate approximation for the mean waiting time in queues with servers experiencing autocorre- lated times to failure. To do this, we employ a three-parameter renewal approximation that represents the autocorrelated times to failure stream. The analysis is exact in the case of phase-type interruption processes if the arrival

David L. Jagerman; Tayfur Altok

177

Diffusion approximations for open queueing networks with service interruptions  

Microsoft Academic Search

This paper establishes functional central limit theorems describing the heavy-traffic behavior of open single-class queueing networks with service interruptions. In particular, each station has a single server which is alternatively up and down. There are two treatments of the up and down times. The first treatment corresponds to fixed up and down times and leads to a reflected Brownian motion,

Hong Chen; Ward Whitt

1993-01-01

178

Approximate Throughput Analysis of Cyclic Queueing Networks with Finite Buffers  

Microsoft Academic Search

An approximation method for obtaining the throughput of cyclic queueing networks with blocking as a function of the number of customers in it is presented. The approximation method was developed for two different blocking mechanisms. It was also extended to the case of the central server model with blocking. Validation tests show that the algorithm is fairly accurate.

Raif O. Onvural; Harry G. Perros

1989-01-01

179

Semaphore queues: modeling multilayered window flow control mechanisms  

Microsoft Academic Search

An open queuing network for analyzing multilayered window flow control mechanisms consisting of different subnetworks is presented. The number of customers in each subnetwork is controlled by a semaphore queue. The queuing network is analyzed approximately using decomposition and aggregation. The approximation was validated against exact numerical and simulation data, and it was found to have an acceptable relative error.

S. Fdida; H. G. Perros; A. Wilk

1990-01-01

180

Lattice networks: capacity limits, optimal routing, and queueing behavior  

Microsoft Academic Search

We study capacity and routing in lattice networks. Such networks are used in regular settings like grid computing and can be seen as an approximation to dense sensor networks. Thus, limits on capacity, optimal routing policies, and performance with nite queues are key issues and are addressed in this paper. In particular, we study the routing algorithms that achieve the

Guillermo Barrenetxea; Baltasar Beferull-lozano; Martin Vetterli

2006-01-01

181

On the psychological cost of waiting in queues  

Microsoft Academic Search

In this research, building on the cognitive stress theories of waiting, we develop and test a model of the psychological cost of waiting in lines. In our model, we consider how the length of the queue, the mean waiting time, and the uncertainty in waiting time affect the accumulation of stress. We carry out an empirical test of the key

Cenk Kocas

2000-01-01

182

Optimum and equilibrium in a transport problem with queue effects  

Microsoft Academic Search

Consider a distribution of citizens in an urban area in which some services (supermarkets, post offices...) are present. Each citizen, in order to use a service, spends an amount of time which is due both to the travel time to the service and to the queue time waiting in the service. The choice of the service to be used is

Gianluca Crippa; Chloé Jimenez; Aldo Pratelli

2008-01-01

183

Analysis of a Queueing Model of the Orwell Slotted Ring.  

National Technical Information Service (NTIS)

A multi-queue system, which is intended to model a local area network with the Orwell slotted ring protocol with one slot is considered. The arrival processes at the stations are independent and identically distributed batch Poisson processes. The destina...

B. Vanarem

1989-01-01

184

PURPLE: Predictive Active Queue Management Utilizing Congestion Information  

Microsoft Academic Search

Active Queue Management (AQM) tries to find a delicate balance between two antagonistic Internet queuing re- quirements: First, buffer space should be maximized to accommo- date the possibly huge transient bursts; second, buffer occupation should be minimum so as not to introduce unnecessary end- to-end delays. Traditional AQM mechanisms have been built on heuristics to achieve this balance, and have

Roman Pletka; Marcel Waldvogel; Soenke Mannal

2003-01-01

185

Voice over IP quality of service using active queue management  

Microsoft Academic Search

This paper presents a comprehensive study about the impact of active queue management (AQM) on voice over Internet protocol (VoIP) quality of service. One of the most representative AQM scheme is analyzed through extensive simulation and its effect on the perceived quality of voice calls is evaluated. Different network scenarios, changing network loads and different scheme control parameters are investigated.

Vitalio Alfonso Reguera; Félix F. Álvarez Paliza; Evelio M. García Fernández

2006-01-01

186

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

187

Prevalence of hypertension in bus drivers.  

PubMed

This paper reports the results of a cross-sectional study conducted to evaluate the prevalence of hypertension in 1500 black and white male bus drivers from a large urban transit system in the US. Data for this study were compiled from the files of an occupational health clinic which conducts biennial medical examinations for drivers' license renewal. To test whether prevalence of hypertension was higher among bus drivers than among employed individuals in general, drivers were compared to three groups: individuals from both a national and local health survey and individuals undergoing baseline health examinations prior to employment as bus drivers. After adjustment for age and race, hypertension rates for bus drivers were significantly greater than rates for each of the three comparison groups. These findings support previous results from international studies of bus drivers suggesting that exposure to the occupation of driving a bus may carry increased health risk. This research has expanded into an on-going study which has the goals of clarifying the extent of hypertension in bus drivers and identifying specific behavioural and occupational factors that may be responsible for increased risk of cardiovascular disease. PMID:3497118

Ragland, D R; Winkleby, M A; Schwalbe, J; Holman, B L; Morse, L; Syme, S L; Fisher, J M

1987-06-01

188

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

189

The Flexible Bus Systems Using Zigbee as a Communication Medium  

Microsoft Academic Search

This paper describes a research on The Flexible Bus Systems (FBS) using Zigbee as a communication medium. The Flexible Bus System is a demand responsive transit (DRT) but it is more efficient and convenient in a sense that it entertains passenger's demands and gives bus locations in real time. The real time synchronization of The Flexible Bus System makes it

Razi Iqbal; Kenichi Yukimatsu; Tatsuya Ichikawa

2011-01-01

190

DEVELOPMENT AND EVALUATION OF INTELLIGENT BUS PRIORITY CONCEPT  

Microsoft Academic Search

Development and laboratory testing of an intelligent concept for providing priority to buses at signalized intersections without disrupting progression are discussed. The concept used bus position information to predict when in the cycle a bus would arrive at the bus stop and stop line of a signalized intersection and to determine whether a bus needs priority. The strategy used to

Kevin N. Balke; Conrad L. Dudek; Thomas Urbanik II

2000-01-01

191

Hazardous bus stop identification: An illustration using GIS  

Microsoft Academic Search

Safety and accessibility to bus transit systems play a vital role in increasing transit market potential. Bus passengers often tend to cross the streets from either behind or in front of the bus as crosswalks do not exist near most bus stops, which are typically away from intersections. These unsafe maneuvers frequently result in either autopedestrian collisions or conflicts. Identifying

Srinivas S. Pulugurtha; Vinay K. Vanapalli

2008-01-01

192

The design of high reliable serial system BUS  

Microsoft Academic Search

With the development of astronavigation and aviation technology, the currently high-reliable serious bus can not meet the requirement fully and totally show at follow aspects: 1 low system bus speed and the bus load up to 85%; 2 low system intelligentize and the bus takes too many time of CPU; 3 imperfect preventive measure for Single Event Upset (SEU) and

Zhu Xiaoyan; Zhang Weigong; Wang Jianfeng; Duan Qingya; Liu Shurong

2010-01-01

193

Automated testing methodologies for low cost, parallel optical bus components  

Microsoft Academic Search

The need for low cost, parallel optical bus modules that are competitively priced with existing copper bus technology necessarily implies a need for low cost testing methodologies. The testing of parallel optical bus components however poses unique challenges for the automated test environment. Optical bus components are high data rate, mixed signal, parallel devices that are still in the early

Kevin Stawiasz; Dan Kuchta; Peter Xiao

1997-01-01

194

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

195

Dual billiards  

NASA Astrophysics Data System (ADS)

CONTENTSIntroduction § 1. Bisecting property § 2. Generating function and periodic points § 3. Several modifications of the dual billiard map § 4. Duality between billiards and dual billiards § 5. A theorem of Poncelet and dual billiards § 6. Integrability § 7. Affine parametrization and explicit formulae § 8. Area spectrum § 9. Invariant curves §10. Dual billiard map at infinity §11. Polygonal dual billiards §12. Affine-regular pentagon §13. Higher-dimensional dual billiardsReferences

Tabachnikov, S.

1993-12-01

196

Honolulu Bus Rapid Transit (BRT) Project Evaluation.  

National Technical Information Service (NTIS)

This reference document was prepared for the Office of Research, Demonstration and Innovation of the Federal Transit Administration (FTA). This case study evaluation of the Honolulu bus rapid transit project is intended to support FTAs ongoing research on...

L. Cham M. Chang J. Chung G. Darido C. Geilfuss D. Henry E. Kim W. Romano D. Schneck

2006-01-01

197

Impact of Fare Collection on Bus Design.  

National Technical Information Service (NTIS)

The primary objectives of this study are: to investigate and evaluate the nature of new bus designs which better accommodate the primary functions of public transit, if the fundamental constraint of on-board, driver monitored, fare collection were removed...

H. Holcombe W. Magro J. Mateyka

1979-01-01

198

Bus Fleet Management Techniques Guide. Final Report.  

National Technical Information Service (NTIS)

The purpose of the Bus Fleet Management Techniques Guide is to provide transit maintenance managers with methods that they can use to derive information for maintenance planning and fleet management. The Guide covers three basic areas: (1) statistical ana...

A. R. Cook T. H. Maze U. Dutta

1985-01-01

199

Bus Fleet Management Principles and Techniques.  

National Technical Information Service (NTIS)

The purpose of the monograph is to demonstrate principles, methods, and techniques that should permit the better management of bus fleets through the systematic use of maintenance records and data. The materials presented will assist the fleet manager in ...

T. H. Maze

1987-01-01

200

Simulation Model of the Bus Stop  

NASA Astrophysics Data System (ADS)

On the basis of the research conducted at the bus stops in Krakow and Warsaw, the movement processes, related with functioning of a bus stop have been identified. As a result, the simulation model imitating its functioning has been formulated and verified. The stop has been analyzed as a system, in which the input flow comprises of municipal bus transport, whereas the service time corresponds the dwell time. The formulas for time losses incurred due to queuing to reach the boarding and alighting zones have been derived, constituting a basis for operative capacity estimation of a bus stop and specifying the selection determinants for the number of boarding and alighting zones in regards to traffic intensity as well as boarding and alighting time.

B?k, Rados?aw

2010-03-01

201

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

202

Effect of queueing disciplines on response times in distributed systems  

SciTech Connect

A distributed program consists of processes, many of which can execute concurrently on different processors in a distributed system of processors. When several processes from the same or different distributed programs have been assigned to a processor in a distributed system, the processor must select the next process to run. The question investigated is: What is an appropriate method for selecting the next process to run. Standard processor queueing disciplines, such as first-come-first-serve and round-robin-fixed-quantum, are studied. The results for four classes of queueing disciplines tested on three problems are presented. These problems were run on a testbed, consisting of a compiler and simulator used to run distributed programs on user-specified architectures.

Williams, E.

1984-01-01

203

AstroBus On-Board Software  

NASA Astrophysics Data System (ADS)

AstroBus on-board software is a customisable software for ERC32 based avionics implementing standard ESA Packet Utilization Standard functions. Its architecture based on generic design templates and relying on a library providing standard PUS TC, TM and event services enhances its reusability on various programs. Finally, AstroBus on-board software development and validation environment is based on last generation tools providing an optimised customisation environment.

Biscarros, D.; Cantenot, C.; Séronie-Vivien, J.; Schmidt, G.

204

AstroBus On-Board Software  

Microsoft Academic Search

AstroBus on-board software is a customisable software for ERC32 based avionics implementing standard ESA Packet Utilization Standard functions. Its architecture based on generic design templates and relying on a library providing standard PUS TC, TM and event services enhances its reusability on various programs. Finally, AstroBus on-board software development and validation environment is based on last generation tools providing an

D. Biscarros; C. Cantenot; J. Séronie-Vivien; G. Schmidt

2003-01-01

205

Asymptotic analysis for closed multichain queueing networks with bottlenecks  

Microsoft Academic Search

We consider a two-chain exponential queueing network with a large number of customers that consists of one infinite-server (IS) station and two processor-sharing (PS) or FCFS single-server stations. The asymptotic behavior of the partition function is studied for such a network when one or both PS (FCFS) nodes are heavily loaded. The results are derived using methods of multidimensional complex

Yaakov Kogan; Andrei Yakovlev

1996-01-01

206

Adaptive fuzzy sliding mode active queue management algorithms  

Microsoft Academic Search

Active queue management (AQM) is aimed at achieving the tradeoff between link utilization and queuing delay to enhance TCP\\u000a congestion control and is expected to perform well for a wider-range of network conditions. Static AQM schemes despite their\\u000a simplicity, often suffer from long response time due to conservative parameter setting to ensure stability. Adaptive parameter\\u000a settings, which might solve this

Xinping Guan; Bo Yang; Bin Zhao; Gang Feng; Cailian Chen

2007-01-01

207

PD-controller: a new active queue management scheme  

Microsoft Academic Search

This paper describes a proportional-differential (PD) control algorithm as a new active queue management (AQM) scheme for TCP\\/IP congestion control. From the viewpoint of the control theory, TCP congestion control system can be regarded as a feedback regulating system. In this paper, a robust AQM called PD-controller is proposed. The design principles of PD-controller are presented in details. Its performance

Jinsheng Sun; Guanrong Chen; King-Tim Ko; Sammy Chan; Moshe Zukerman

2003-01-01

208

Design of neural model predictive controller for active queue management  

Microsoft Academic Search

Recently many active queue management (AQM) algorithms have been proposed to address performance degradations of end-to-end congestion control. However, these AQM algorithms show weaknesses to detect and control congestion under dynamically changing network situations. In this paper, we use a neural model predictive controller (NMPC) for AQM in the Internet based on neural networks. Which uses P 1,2 Pade's approximation

Yi-Bin Yu; Chang-Xiu Cao; Guo-Yan Yu; Chang-Bing Li

2005-01-01

209

Analyticity of single-server queues in light traffic  

Microsoft Academic Search

Recently, several methods have been proposed to approximate performance measures of queueing systems based on their light traffic derivatives, e.g., the MacLaurin expansion, the Padé approximation, and interpolation with heavy traffic limits. The key condition required in all these approximations is that the performance measures be analytic when the arrival rates equal to zero. In this paper, we study theGI\\/G\\/1

Jian-qiang Hu

1995-01-01

210

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

211

Queue Position in the Endoscopic Schedule Impacts Effectiveness of Colonoscopy  

PubMed Central

OBJECTIVES Endoscopist fatigue potentially impacts colonoscopy. Fatigue is difficult to quantitate, but polyp detection rates between non-fatigued and fatigued time periods could represent a surrogate marker. We assessed whether timing variables impacted polyp detection rates at a busy tertiary care endoscopy suite. METHODS Consecutive patients undergoing colonoscopy were retrospectively identified. Indications, clinical demographics, pre-procedural, and procedural variables were extracted from chart review; colonoscopy findings were determined from the procedure reports. Three separate timing variables were assessed as surrogate markers for endoscopist fatigue: morning vs. afternoon procedures, start times throughout the day, and queue position, a unique variable that takes into account the number of procedures performed before the colonoscopy of interest. Univariate and multivariate analyses were performed to determine whether timing variables and other clinical, pre-procedural, and procedural variables predicted polyp detection. RESULTS During the 4-month study period, 1,083 outpatient colonoscopy procedures (57.5±0.5 years, 59.5% female) were identified, performed by 28 endoscopists (mean 38.7 procedures/endoscopist), with a mean polyp detection rate of 0.851/colonoscopy. At least, one adenoma was detected in 297 procedures (27.4%). A 12.4% reduction in mean detected polyps was detected between morning and afternoon procedures (0.90±0.06 vs. 0.76±0.06, P = 0.15). Using start time on a continuous scale, however, each elapsed hour in the day was associated with a 4.6% reduction in polyp detection (P = 0.005). When queue position was assessed, a 5.4% reduction in polyp detection was noted with each increase in queue position (P = 0.016). These results remained significant when controlled for each individual endoscopist. CONCLUSIONS Polyp detection rates decline as time passes during an endoscopist’s schedule, potentially from endoscopist fatigue. Queue position may be a novel surrogate measure for operator fatigue.

Lee, Alexander; Iskander, John M.; Gupta, Nitin; Borg, Brian B.; Zuckerman, Gary; Banerjee, Bhaskar; Gyawali, C. Prakash

2014-01-01

212

Queues allocation for multiple input-queued switches  

Microsoft Academic Search

To meet the increasing requirement for high speed switches, a multiple input-queued (MIQ) switch is explored. Rather than handling the scheduling problem heavily focused on by many researchers, a proposed dynamic queue allocation algorithm is used to handle non-uniform or hot-spot traffic. Although the performance of the original algorithm is analyzed by N.K. Sharma and M.R. Pinnu (see Parallel Computing,

Joe Shang-Chieh Wu; Raymond Miler; Tsern-Huei Lee; Ying-Dar Lin

2001-01-01

213

Queue monitor toolkit for tracking of PACS clinical workflow  

NASA Astrophysics Data System (ADS)

Expectation of rapid image retrieval and distribution from PACS contributes to increased information technology (IT) infrastructure investments and continuing demands upon PACS administrators to respond to "slow" system calls. Studies show that it is important for computer users to be able to check on the progress of their task via progress indicators (e.g., time left to download file) to know that the computer is still working. By analogy, the ability to provide predicted delivery times to a PACS user may curb user expectations for "fast" response especially during peak hours. Allowing for some periods of slow response means PACS infrastructure do not have to be overbuilt and also reduce time spent by PACS administrators fielding user inquiries on image status. For this condition, a queryable PACS queue monitor is the cornerstone for providing a progress indicator to the user. The typical PACS server holds image file information and destination workstation information in a queue until the RetrieveSend process can send the image. We developed an agent that queries the contents of the PACS RetrieveSend queue in real-time and coded an algorithm to predict delivery time. Delivery time can be predicted from the number and types of images in progress and the download time of prior images that accounts for network load and performance at that time of day. We have developed a PACS queue monitor prototype that is being tested on clinical data using the PACS Simulator at the Imaging Processing and Informatics (IPI) Laboratory of the University of Southern California (USC).

King, Nelson E.; Documet, Jorge; Zhou, Zheng; Liu, Brent

2005-04-01

214

Performance evaluation of input and output queueing techniques in ATM switching systems  

NASA Astrophysics Data System (ADS)

In this paper, alternatives to model a fast packet switching system are analyzed. A nonblocking switch fabric which runs at the same speed as the input/output links is considered. The performance of the considered approaches have been derived by theoretical analysis and computer simulations. Performance comparison between input queueing approaches with different selection policies are presented. Novel input and output queueing techniques are also proposed. In particular it is shown that, depending on the implementation, the novel input queueing approach studied in this paper achieves the same performance as the optimum (output) queueing alternative, without resorting to a faster packet switch fabric.

Delre, Enrico; Fantacci, Romano

1993-10-01

215

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

216

Systems evaluation of thermal bus concepts  

NASA Technical Reports Server (NTRS)

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

Stalmach, D. D.

1982-01-01

217

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

218

Dual billiards  

Microsoft Academic Search

CONTENTSIntroduction § 1. Bisecting property § 2. Generating function and periodic points § 3. Several modifications of the dual billiard map § 4. Duality between billiards and dual billiards § 5. A theorem of Poncelet and dual billiards § 6. Integrability § 7. Affine parametrization and explicit formulae § 8. Area spectrum § 9. Invariant curves §10. Dual billiard map

S. Tabachnikov

1993-01-01

219

SecBus: Operating System controlled hierarchical page-based memory bus protection  

Microsoft Academic Search

This paper presents a new two-levels page-based memory bus protection scheme. A trusted Operating System drives a hardware cryptographic unit and manages security contexts for each protected memory page. The hardware unit is located between the internal system bus and the memory controller. It protects the integrity and confidentiality of selected memory pages. For better acceptability the processor (CPU) architecture

Lifeng Su; Stephan Courcambeck; Pierre Guillemin; Christian Schwarz; Renaud Pacalet

2009-01-01

220

An Algebra for Queueing Networks with Time-Varying Service and Its Application to the Analysis of Integrated Service Networks  

Microsoft Academic Search

Abstract: We introduce a queueing network model that allows us to capture the time - varying service delivered to a tra c stream due to the presence of random perturbations (e g cross - tra c in a communication network) We rst present the model for a single queue and then describe how such queues may be intercon - nected

Rajeev Agrawal; François Baccelli; Rajendran Rajan

2004-01-01

221

Asymptotic expansions for waiting time probabilities in an M\\/G\\/1 queue with long-tailed service time  

Microsoft Academic Search

We consider anM\\/G\\/1 queue with FCFS queue discipline. We present asymptotic expansions for tail probabilities of the stationary waiting time when the service time distribution is longtailed and we discuss an extension of our methods to theM[x]\\/G\\/1 queue with batch arrivals.

E. Willekens; J. L. Teugels

1992-01-01

222

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

223

Instability of FIFO at Arbitrarily Low Rates in the Adversarial Queueing Model  

Microsoft Academic Search

We study the stability of the commonly used packet forwarding protocol, FIFO (First In First Out), in the adversarial queueing model. We prove that FIFO can become unstable, i.e., lead to unbounded buffer- occupancies and queueing delays, at arbitrarily low injection rates. In order to demonstrate instability at rate , we use a network of size polynomial in .

Rajat Bhattacharjee; Ashish Goel

2003-01-01

224

Statistical Analysis of a Telephone Call Center: A Queueing-Science Perspective  

Microsoft Academic Search

A call center is a service network in which agents provide telephone-based services. Customers that seek these services are delayed in tele-queues. This paper summarizes an analysis of a unique record of call center operations. The data comprise a complete operational history of a small banking call center, call by call, over a full year. Taking the perspective of queueing

Lawrence Brown; Noah Gans; Avishai Mandelbaum; Anat Sakov; Haipeng Shen; Sergey Zeltyn; Linda Zhao; Novemer

2005-01-01

225

Switching Resilient PI Controllers for Active Queue Management of TCP Flows  

Microsoft Academic Search

Active Queue Management (AQM) is used in computer networks to increase link utilization with less queueing delays. The fluid flow model of TCP based on delay differential equations supplies the mathematical background for modelling the AQM as a feedback system. Recently various PI and PID controllers are designed for this feedback system, [7], [18]. In this paper, we consider the

Deniz Üstebay; Hitay Özbay

2007-01-01

226

Bandwidth allocation for non-responsive flows with active queue management  

Microsoft Academic Search

This paper addresses the problem of configuring active queue management systems (e.g. WRED and RIO) for service level specifications in internetworks. In particular, we focus on assured forwarding (AF) for non-responsive flows in differentiated services networks. The difficulty is to determine the correct queue level thresholds that will result in correct drop rates for various AF precedence levels under any

Ed Bowen; Clark Jeffries; Lukas Kencl; Andreas Kind; Roman Pletka

2002-01-01

227

RBF-PID Based Adaptive Active Queue Management Algorithm for TCP Network  

Microsoft Academic Search

Active queue management (AQM) has been widely used for congestion avoidance in transmission control protocol (TCP) networks. Although numerous AQM schemes have been proposed to regulate a queue size close to a reference level, most of them are incapable of adequately adapting to TCP network dynamics due to TCP's non-linearity and time-varying stochastic properties. To alleviate these problems, we propose

Wang Jun-song; Gao Zhi-wei; Shu Yan-tai

2007-01-01

228

The method of active queue management based on air traffic network  

Microsoft Academic Search

As the loss probability could be the indicator of congestion possibility, the theoretical study of air traffic network was how to determinate active queue management (AQM) based on random condition. Then, a random early detection (RED) method for air traffic network was proposed, which determined the soft loss strategy with deducing the maximum threshold and average queue length. Compared to

Jun Hu; Qian Li; Yu-qing Hu

2011-01-01

229

Bayesian control of the number of servers in a GI \\/ M \\/ c queueing system  

Microsoft Academic Search

In this paper we consider the problem of designing a GI\\/M\\/c queueing system. Given arrival and service data, our objective is to choose the optimal number of servers so as to minimize an expected cost function which depends on quantities, such as the number of customers in the queue. A semiparametric approach based on Erlang mixture distributions is used to

M. Concepción Ausín; Rosa E. Lillo; Michael P. Wiper

2007-01-01

230

STATISTICAL INFERENCE ON THE TRAFFIC INTENSITY FOR THE M\\/M\\/s QUEUEING SYSTEM  

Microsoft Academic Search

In the paper it is shown that, for the certain plans of observations on the M\\/M\\/s queueing system's performances, there exists a uniformly most powerful test of statistical hypothesis on the trac intensity. 1. Preliminaries. Let us consider the M=M=s queueing system. That means we have the system with poissonian input with parameter ; > 0 and exponential output of

Alexei Leahu

231

Resequencing Delays Under Multipath Routing - Asymptotics in a Simple Queueing Model.  

National Technical Information Service (NTIS)

We study the resequencing delay caused by multi-path routing. We use a queueing model which consists of parallel queues to model the network routing behavior. We define a new metric, denoted by gamma, to study the impact of resequencing on the customer en...

Y. Han A. M. Makowski

2005-01-01

232

Performance Evaluation of Serial Photolithography Clusters: Queueing Models, Throughput and Workload Sequencing  

Microsoft Academic Search

For clustered configuration of a photolithography toolset, operating under a scheduling policy inducing serial processing, measures of system performance are deduced. Queueing models demonstrate that, due to the parallelism inherent in the system configuration, the normalized cycle time behavior is different than that of the standard single server queue. Cluster throughput is evaluated based on measures of the frequency and

James R. Morrison; Beverly Bortnick; Donald P. Martin

2006-01-01

233

A Multilayer Client-Server Queueing Network Model with Synchronous and Asynchronous Messages  

Microsoft Academic Search

We analyze a multilayered queueing network that models a client-server system where clients and servers communicate via synchronous and asynchronous messages. The servers are organized in groups such that they form a multilayered hierarchical structure. The queueing network is approximately analyzed using a decomposition algorithm. Numerical tests show that the approximation algorithm has a good accuracy.

Sridhar Ramesh; Harry G. Perros

2000-01-01

234

A multi-layer client-server queueing network model with synchronous and asynchronous messages  

Microsoft Academic Search

We analyze a multi-layered queueing network that models a client-server system where clients and servers communicate via synchronous and asynchronous messages. The servers are organized in groups such that they form a multi-layered hierarchical structure. The queueing network is analyzed approximately using a decomposition algorithm. Numerical tests show that the approximation algorithm has a good accuracy.

Sridhar Ramesh; Harry G. Perros

1998-01-01

235

A discrete-time queueing model of the shared buffer ATM switch with bursty arrivals  

Microsoft Academic Search

We model the shared buffer ATM switch as a discrete-time queueing system. The arrival process to each port of the ATM switch is assumed to be bursty and it is modelled by an interrupted Bernoulli process. The discrete-time queueing system is analyzed approximately. It is first decomposed into subsystems, and then each subsystem is analyzed separately. The results from the

S. Hong; H. G. Perros; H. Yamashita

1993-01-01

236

A unified architecture for the design and evaluation of wireless fair queueing algorithms  

Microsoft Academic Search

Fair queueing in the wireless domain poses significant challenges due to unique issues in the wireless channel such as location- dependent and bursty channel errors. In this paper, we present a wireless fair service model that captures the scheduling requirements of wireless scheduling algorithms, and present a unified wireless fair queueing architecture in which scheduling algorithms can be designed to

Thyagarajan Nandagopal; Songwu Lu; Vaduvur Bharghavan

1999-01-01

237

A Unified Architecture for the Design and Evaluation of Wireless Fair Queueing Algorithms  

Microsoft Academic Search

Fair queueing in the wireless domain poses significant challenges due to unique issues in the wireless channel such as location-dependent and bursty channel errors. In this paper, we present a wireless fair service model that captures the scheduling requirements of wireless scheduling algorithms, and present a unified wireless fair queueing architecture in which scheduling algorithms can be designed to achieve

Thyagarajan Nandagopal; Songwu Lu; Vaduvur Bharghavan

2002-01-01

238

Empirical Evaluation of a Queueing Network Model for Semiconductor Wafer Fabrication  

Microsoft Academic Search

This paper concerns performance modeling of semiconductor manufacturing operations. More specifically, it focuses on queueing network models for an analysis of wafer fabrication facilities. The congestion problems that plague wafer fabrication facilities are described in general terms, and several years' operating data from one particular facility are summarized. A simple queueing network model of that facility is constructed, and the

HONG CHEN; J. MICHAEL HARRISON; AVI MANDELBAUM; ANN VAN ACKERE; LAWRENCE M. WEIN

1988-01-01

239

A Large-Scale Agent-Based Traffic Microsimulation Based On Queue Model  

Microsoft Academic Search

We use the so-called queue model introducted by Gawron as the base of the traffic dynamics in our micro-simulation. The queue model describes the links with a flow capacity that limits the number of agents that can leave the link and a space constraint which defines the limit of the number of agents that can be on a link at

Nurhan Cetin; Adrian Burri; Kai Nagel

240

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

Microsoft Academic Search

The RED active queue management algorithm allows net- work operators to simultaneously achieve high throughput and low average delay. However, the resulting average queue length is quite sensitive to the level of congestion and to the RED parameter settings, and is therefore not pre- dictable in advance. Delay being a major component of the quality of service delivered to their

Sally Floyd; Ramakrishna Gummadi; Scott Shenker

2001-01-01

241

The State of Urban Mass Transportation Research, Development, and Demonstration. Volume III: Bus Transit.  

National Technical Information Service (NTIS)

Urban bus systems are described and related to other transportation modes. Market for bus transit and costs are discussed and the impacts of urban bus transit on riders, operators, the public and industry are presented. Area studies include Bus Technology...

E. Stabler H. Margolis S. F. Ugel

1972-01-01

242

ORION II bus demonstration. Demonstration report (Final)  

SciTech Connect

The Central New York Regional Transportation Authority conducted an 18-month demonstration to determine how the ORION II bus operates in actual service. The ORION II vehicle is a small low floor, accessible heavy duty, diesel-powered transit bus designed to meet the needs of the elderly and handicapped. It has the capacity to seat 26 passengers with 4 wheelchair lockdowns. Side and rear doors are equipped with electrically powered ramps. Eight Thomas vehicles (22-foot, 11,500 lbs, wheelchair equipped, gasoline fueled) were also tested during the demonstration period. Operations (fuel and oil usage) and maintenance (scheduled and unscheduled) data were collected and charted-out in the report as well as driver, passenger, and maintenance surveys. This report provides descriptions, photographs, and comparison charts of both the diesel-fueled ORION II transit bus and the gasoline-fueled Thomas vehicles along with the demonstration test plan, evaluations, conclusions, and survey results.

Shanley, J.

1989-02-01

243

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

244

45 CFR 1310.17 - Driver and bus monitor training.  

Code of Federal Regulations, 2010 CFR

45 Public Welfare 4 2010-10-01...2010-10-01 false Driver and bus monitor training...Section 1310.17 Public Welfare Regulations Relating to Public Welfare (Continued...Requirements § 1310.17 Driver and bus monitor...

2010-10-01

245

45 CFR 1310.17 - Driver and bus monitor training.  

Code of Federal Regulations, 2010 CFR

45 Public Welfare 4 2009-10-01...2009-10-01 false Driver and bus monitor training...Section 1310.17 Public Welfare Regulations Relating to Public Welfare (Continued...Requirements § 1310.17 Driver and bus monitor...

2009-10-01

246

Bus Rapid Transit: A Smart Alternative for Medium Sized Communities.  

National Technical Information Service (NTIS)

Many medium sized communities offer public bus transportation, however, this made does not always keep pace with growing demand for quick and efficient service. In an effort to respond to this rising demand, innovative new bus services have been introduce...

K. Ayres-Palanuk K. Hunter-Zaworski

1997-01-01

247

Connecticut Nutmeg Fuel Cell Bus Project: First Analysis Report.  

National Technical Information Service (NTIS)

This report summarizes the experience and early results from a fuel cell bus demonstration funded by the Federal Transit Administration (FTA) under the National Fuel Cell Bus Program (NFCBP). A team led by the Northeast Advanced Vehicle Consortium and UTC...

K. Chandler L. Eudy

2012-01-01

248

Dynamics and schedule of shuttle bus controlled by traffic signal  

NASA Astrophysics Data System (ADS)

We study the dynamical behavior of a shuttle bus moving through a traffic signal. The dynamics of the bus is expressed in terms of the nonlinear maps. The bus dynamics is controlled by varying the loading parameter, the cycle time of signal, and the degree of speedup. We show the dependence of the tour time on both loading parameter and cycle time. The fluctuation of boarding passengers is highly reduced by varying the cycle time. When the bus speeds up to retrieve the delay induced by loading the passengers, the bus behavior also changes highly. The shuttle bus schedule is connected with the complex motion of the shuttle bus. The region map (phase diagram) is shown to control the complex motion of the bus.

Nagatani, Takashi

2008-10-01

249

This Bus Safety Plan Emphasizes Student Awareness and Driver Training.  

ERIC Educational Resources Information Center

School bus safety includes the development of safe drivers as well as student awareness. Outlines the McDowell County schools' (North Carolina) bus safety program. Includes discussion of whether high school students should drive school buses. (MD)

Grier, Terry B.

1986-01-01

250

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

251

SunLine Test Drives Hydrogen Bus: Hydrogen Fuel Cell& Infrastructure Technologies Program, Fuel Cell Bus Demonstration Projects (Fact Sheet)  

SciTech Connect

Fact sheet describes the ThunderPower hydrogen fuel cell bus that was demonstrated at SunLine Transit Agency from November 2002 to February 2003. The bus was evaluated by DOE's Advanced Vehicle Testing Activity.

Eudy, L.

2003-08-01

252

Design of vehicle bus data acquisition and fault diagnosis system  

Microsoft Academic Search

This paper introduces the overall design of vehicle bus data acquisition and fault diagnosis system on the basis of OBD, focusing on its lower computer system and the upper computer system design principles. This system is based on the widely used CAN bus technology, to extract the vehicle's status or fault information. The CAN bus adopts the SAE J1939 protocol

Wang Quanqi; Wang Jian; Wang Yanyan

2011-01-01

253

Framework for Bus Rapid Transit Development and Deployment Planning  

Microsoft Academic Search

This report presents the results of its investigation into deployment planning for bus rapid transit systems. In this study, we conducted a macro-scale examination of bus rapid transit systems from technical, operational, institutional, and planning perspectives. We then developed the theoretical foundation for a deployment planning framework for bus rapid transit systems that specifically takes into account the unique features

Mark A. Miller; Yafeng Yin; Tunde Balvanyos; Avishai Ceder

2004-01-01

254

Evaluating new start transit program performance: Comparing rail and bus  

Microsoft Academic Search

This study by Lyndon Henry and Todd Litman compares public transit performance between U.S. cities that expanded rail systems and those that expanded bus systems. There is ongoing debate over the relative advantages of rail and bus transit investments. Rail critics assert that cities which expand their bus transit systems exhibit better performance than those that expand rail systems. This

Lyndon Henry; Todd Litman

2006-01-01

255

Electric bus operations: A feasibility study. Research report  

Microsoft Academic Search

This study determines the technical and economic feasibility of electric bus operations. A review of electric vehicle technology with an emphasis on battery-powered electric vehicles is performed, and the availability and use of electric buses are identified. A methodology is presented for selection of bus routes most suitable for electric bus operations using the Capital Metropolitan Transportation Authority as a

T. M. Fowler; M. A. Euritt; C. M. Walton

1995-01-01

256

Cost Analysis of Community Bus System Operations in Japan  

Microsoft Academic Search

In Japan, many community bus systems were already in operation when the bus service industry was deregulated in 2002. Most of these services depend on subsidies from the local municipalities and many of them have now been forced to discontinue due to budget cuts of the subsidizing local governments.As a case study of a successful operation of a community bus

Yasuo Tomita; Kouki Iwamoto

2009-01-01

257

A private-public comparison of bus service operators  

Microsoft Academic Search

Due to the steady increase in the use of private autos in Japan, the bus business is facing hard times. In particular, bus services owned by public organizations have been struggling with increases in operating deficits and subsidies, so that recently in many cities there has been a call for restructuring. Publicly and privately owned bus operators co-exist in the

Fumitoshi Mizutani; Takuya Urakami

2002-01-01

258

The Conceptual Design of New Bus Stop Board  

Microsoft Academic Search

This paper analyzes systematically widespread problems about the most of bus stop boards existing in domestic ordinary, which include incomplete bus information in one area, lack of traffic information about the city and low humanity. In view of these problems,the paper proposes conceptual design of anew bus stop board on the basis of control ability and opening information. The conceptual

Youjun Liu; Daohai Zhang; Song Gao

2008-01-01

259

Trends in Bus Transit Operations, 1960-1974.  

National Technical Information Service (NTIS)

This report analyzes the historical patterns of bus transit operations from 1960 to 1974 using data from 50 bus operations. Because of limitations on the available data, the analyzed data do not represent the universe of bus operations, nor is it a random...

1977-01-01

260

Improving bus service quality and information in Winchester  

Microsoft Academic Search

This paper reports the results of a package of measures, contained within a quality bus partnership (QBP), designed to improve bus service quality and information on three city centre routes in Winchester, including the Park and Ride (P&R) service. These measures were implemented by Hampshire County Council, Stagecoach Bus Company and Winchester City Council as part of the EU sponsored

Graham Wall; Mike McDonald

2007-01-01

261

Designing Guidable Bus Transit Database for Chinese Cities  

Microsoft Academic Search

In a complicated bus system, bus passenger guidance requires consistent database. Effective guidance needs to provide information on trip origin, destination and transfer. The transfer component is the major concern, which can only be facilitated with a carefully designed hierarchical data model. A three-tier structure of the model is presented. Some practical issues of managing a bus transit database with

2007-01-01

262

Bus Lane with Intermittent Priority (BLIMP) Concept Simulation Analysis  

Microsoft Academic Search

This report discusses the results of a preliminary implementation study to determine the potential impacts of a new and innovative transit priority treatment along a BRT corridor in Eugene, Oregon. The bus lane with intermittent priority (BLIMP) utilizes dynamic lane assignment to designate an exclusive bus lane on a temporary, bus-actuated basis. The temporary lane is designated via overhead variable

Graham Carey; Thomas Bauer; Karen Giese

2009-01-01

263

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

264

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.

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

2011-01-01

265

Modeling Crosstalk Effects in CNT Bus Architectures  

Microsoft Academic Search

Carbon nanotubes (CNTs) have been widely proposed as interconnect fabric for nano and very deep submicron (silicon-based) technologies due to their robustness to electromigration. In this paper, issues associated with crosstalk among bus lines implemented by CNTs are investigated in detail. CNT-based interconnects are modeled and the effects of crosstalk on performance and correct operation are evaluated by simulation. Existing

Daniele Rossi; José Manuel Cazeaux; Cecilia Metra; Fabrizio Lombardi

2007-01-01

266

Interconnect testing for bus-structured systems  

Microsoft Academic Search

This paper considers the problem of generating test vectors for interconnect testing within a boundary-scan environment. Provision is made for both detection and diagnosis of single and multiple bridging faults and stuck faults on driver and bus lines. The procedures developed cater for all combinations of structures within a board, and allow for the special problems of CMOS elements. The

P. J. Dickinson; B. R. Wilkins

1993-01-01

267

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

268

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

269

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

270

Classification of bus transit policy variables  

Microsoft Academic Search

This paper develops a conceptual model to classify bus transit policy variables based on their effects on the performance levels of the various inputs and total performance measured by the presence or absence of (dis)economies of scale. The four groups of variables identified in the study include those withi. Strictly positive outcome—these include speed, and the ratio of employer to

Kofi Obeng

1987-01-01

271

Modelling user perception of bus transit quality  

Microsoft Academic Search

This article evaluates how bus users perceive the quality of their public transport service. In particular it looks at how perception of quality varies according to the available information. The experiment compares an overall evaluation of service quality before and after making passengers reflect on the importance of certain fundamental system variables which they may not have previously considered.Focus groups

Luigi dell’Olio; Angel Ibeas; Patricia Cecín

2010-01-01

272

Multiple period optimization of bus transit systems  

Microsoft Academic Search

Analytic models are developed for optimizing bus services with time dependence and elasticity in their demand characteristics. Some supply parameters, i.e. vehicle operating costs and speeds are also allowed to vary over time. The multiple period models presented here allow some of the optimized system characteristics (e.g. route structure) to be fized at values representing the best compromise over different

Shyue Koong Chang; Paul M. Schonfeld

1991-01-01

273

Exploring bus transfer behaviour in metropolitan Melbourne  

Microsoft Academic Search

Although passengers dislike transferring between routes, quality transit systems need to facilitate easy transfers to provide competitive city wide access to the private car. This paper reviews bus transfer behaviour in Melbourne, Australia and aims to understand factors which enable transfer behaviour with a particular focus on buses. The research also explores if high transfer rates can be associated with

Graham Currie; Chris Loader

2009-01-01

274

EMI/EMP Resistant Data Bus.  

National Technical Information Service (NTIS)

This document is the final report of a development program concerned with the design and fabrication of an eight station EMI/EMP resistant avionic data bus. Airborne avionics systems are moving toward the use of party line multiplex data buses for the tra...

J. E. Shaunfield

1976-01-01

275

Transit bus operation with methanol fuel  

Microsoft Academic Search

American and European technology is being used to demonstrate the suitability of neat methanol as a fuel for transit buses. The project is sponsored by the California Energy Commission (CEC), and transit buses are being operated by the golden Gate Bridge, Highway and Transportation District (GGTD). Project management and bus testing are performed by Acurex Corporation. Test data are being

M. D. Jackson; S. Unnasch; C. Sullivan

1985-01-01

276

Transit bus operation with methanol fuel  

Microsoft Academic Search

American and European technology is being used to demonstrate the suitability of neat methanol as a fuel for transit buses. The project is sponsored by the California Energy Commission (CEC), and transit buses are being operated by the Golden Gate Bridge, Highway and Transportation District (GGTD). Project management and bus testing are performed by Acurex Corporation. Test data are being

M. D. Jackson; S. Unnasch; C. Sullivan; R. A. Renner

1985-01-01

277

Bus error detection employing parity verification  

US Patent & Trademark Office Database

A bus error detection system is used to detect binary bus error signals. The bus lines include an odd parity line and an even parity line. A clock means provides at least two clock signal phases. An activatable driver drives both of the odd and the even parity lines to the same predefined logic level each time a first clock signal phase occurs. A parity checker coupled to the drive checks during a second clock signal phase the parity of the binary signals which appeared on said bus lines during a preceding first clock signal phase. The driver then drives either the odd or the even parity lines to a predefined logic state according to the parity determined by the parity checker during the second clock signal phase. A verification circuit verifies that only one of the odd and the even parity lines has been driven to a predefined logic state during said second clock phase, and that of both the odd and the even parity lines have been driven during said first clock signal phase to the same predefined logic level.

1989-04-25

278

Double-bus fiber optic sensor network  

Microsoft Academic Search

Despite advantages of distributed fiber optic sensor systems, the stability, reliability and limitation of physical parameters detected by the systems are still the bottlenecks of the applications in industrial control fields. In this paper, we compare different structures of fiber optic sensor networks based on special needs for manufacturing control and monitoring. A double-bus fiber optic sensor network directly used

Xiaohan Sun; Mingde Zhang; Suiren Wan; Daxing Xu; Dong di; Wenbin Xu; Liao Hao; Jingling He; Ning Liu

1996-01-01

279

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

280

An evaluation of a lane support system for bus rapid transit on narrow shoulders and the relation to bus driver mental workload  

Microsoft Academic Search

The use of dedicated bus shoulders is a key method for implementing bus rapid transit (BRT) in areas that do not have the space for additional infrastructure. However, the narrow width of the bus shoulder and the need to anticipate traffic hazards in the adjacent lane can both be significant stressors for bus drivers. Bus driver mental workload and stress

Nicholas J. Ward; Craig Shankwitz; Alec Gorgestani; Max Donath; Dick de Waard; Erwin R. Boer

2006-01-01

281

Numerical study of urban traffic flow with dedicated bus lane and intermittent bus lane  

NASA Astrophysics Data System (ADS)

Based on the cellular automaton traffic flow model and the concept of public transport priority, a two-lane traffic model with an intermittent bus lane is proposed and the properties of urban traffic flow are studied. The cases of traffic with a dedicated bus lane (DBL), an intermittent bus lane (IBL) and an ordinary two-lane traffic are simulated, and comparisons in the form of the fundamental diagrams and the velocity-density profiles are made between them. It is shown that the DBL has the advantage of freeing buses from traffic interference and also has the disadvantage of disrupting traffic, the IBL is more efficient in improving the bus flow than ordinary two-lane traffic and maintaining the car flow at a higher level at the same time than the DBL, while the ordinary two-lane traffic suppresses public transportation and is not advantageous in easing urban traffic congestion. Also it is indicated that the DBL is only appropriate for low traffic flow in a two-lane traffic system, and this limitation can be partly overcome by opening the bus lane to general traffic intermittently when the bus lane is not in use by buses.

Zhu, H. B.

2010-08-01

282

Bus transit system: Its underutilized potential. Final report  

SciTech Connect

The main objectives of this study are to: Clearly define an upgraded bus transit system; Find out and evaluate present condition of bus services with respect to their upgrading from the simple service in mixed traffic in urban streets; Define the reasons why and under what conditions bus service improvements should be introduced; Define the obstacles commonly encountered in implementing and in maintaining measures of upgrading bus services; Recommend policies and actions which would overcome these obstacles and allow development of bus systems which have considerably higher level of efficiency, passenger attraction and positive impact on urban quality of life.

Vuchic, V.; Bruun, E.C.; Krstanoski, N.; Shin, Y.E.; Kikuchi, S.

1994-05-01

283

Priorities for an age-friendly bus system.  

PubMed

This article presents the results of a study on the barriers and facilitators to bus use for people aged 60 or older. Two complementary methodologies, nominal group technique and focussed ethnography, were used to identify barriers and facilitators and rank their importance. Two sample sites from Queensland, Australia, were selected, with 227 people participating in the nominal group technique and 40 people participating in the focussed ethnography component. Seven priorities for age-friendly bus systems emerged from the data: vehicle entrance/exit; bus driver friendliness and helpfulness; timetables and scheduling of buses; bus stop locations; pedestrian infrastructure; information and training for older people; and bus routes and destinations. These findings will assist researchers, policy makers, and transport providers to set evidence-based strategic directions for creating age-friendly bus systems. Both methods provide complementary perspectives on bus usability, which could not be gained from either method alone. PMID:20731892

Broome, Kieran; Worrall, Linda; McKenna, Kryss; Boldy, Duncan

2010-09-01

284

Simple Queueing Model Applied to the City of Portland  

NASA Astrophysics Data System (ADS)

We use a simple traffic micro-simulation model based on queueing dynamics as introduced by Gawron [IJMPC, 9(3):393, 1998] in order to simulate traffic in Portland/Oregon. Links have a flow capacity, that is, they do not release more vehicles per second than is possible according to their capacity. This leads to queue built-up if demand exceeds capacity. Links also have a storage capacity, which means that once a link is full, vehicles that want to enter the link need to wait. This leads to queue spill-back through the network. The model is compatible with route-plan-based approaches such as TRANSIMS, where each vehicle attempts to follow its pre-computed path. Yet, both the data requirements and the computational requirements are considerably lower than for the full TRANSIMS microsimulation. Indeed, the model uses standard emme/2 network data, and runs about eight times faster than real time with more than 100 000 vehicles simultaneously in the simulation on a single Pentium-type CPU. We 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 destination assignment which generates about half a million trips for the morning peak. Route assignment is done by iterative feedback between micro-simulation and router. An iterative solution of the route assignment for the above problem can be achieved within about half a day of computing time on a desktop workstation. We compare results with field data and with results of traditional assignment runs by the Portland Metropolitan Planning Organization. Thus, with a model such as this one, it is possible to use a dynamic, activities-based approach to transportation simulation (such as in TRANSIMS) with affordable data and hardware. This should enable systematic research about the coupling of demand generation, route assignment, and micro-simulation output.

Simon, Patrice M.; Esser, Jörg; Nagel, Kai

285

A comparison of queueing, cluster and distributed computing systems  

NASA Technical Reports Server (NTRS)

Using workstation clusters for distributed computing has become popular with the proliferation of inexpensive, powerful workstations. Workstation clusters offer both a cost effective alternative to batch processing and an easy entry into parallel computing. However, a number of workstations on a network does not constitute a cluster. Cluster management software is necessary to harness the collective computing power. A variety of cluster management and queuing systems are compared: Distributed Queueing Systems (DQS), Condor, Load Leveler, Load Balancer, Load Sharing Facility (LSF - formerly Utopia), Distributed Job Manager (DJM), Computing in Distributed Networked Environments (CODINE), and NQS/Exec. The systems differ in their design philosophy and implementation. Based on published reports on the different systems and conversations with the system's developers and vendors, a comparison of the systems are made on the integral issues of clustered computing.

Kaplan, Joseph A.; Nelson, Michael L.

1993-01-01

286

A queueing model for chronic recurrent conditions under panel observation.  

PubMed

In many chronic conditions, subjects alternate between an active and an inactive state, and sojourns into the active state may involve multiple lesions, infections, or other recurrences with different times of onset and resolution. We present a biologically interpretable model of such chronic recurrent conditions based on a queueing process. The model has a birth-death process describing recurrences and a semi-Markov process describing the alternation between active and inactive states, and can be fit to panel data that provide only a binary assessment of the active or inactive state at a series of discrete time points using a hidden Markov approach. We accommodate individual heterogeneity and covariates using a random effects model, and simulate the posterior distribution of unknowns using a Markov chain Monte Carlo algorithm. Application to a clinical trial of genital herpes shows how the method can characterize the biology of the disease and estimate treatment efficacy. PMID:15737093

Crespi, Catherine M; Cumberland, William G; Blower, Sally

2005-03-01

287

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

288

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.

289

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

290

Initiating Bus Rapid Transit in Jakarta, Indonesia  

Microsoft Academic Search

On February 1, 2004, a 12.9-km (8-mi) bus rapid transit (BRT) line began revenue operation in Jakarta, Indonesia. The BRT line has incorporated most of the characteristics of BRT systems. The line was implemented in only 9 months at a cost of less than US$1 million\\/km ($1.6 million\\/mi). Two additional lines are scheduled to begin operation in 2005 and triple

John P Ernst

2005-01-01

291

Mobile Journey Planning for Bus Passengers  

Microsoft Academic Search

Developments in mobile technology offer new ways of supporting mobile decision making. One application domain in the area\\u000a of Location Based Services (LBS) is the delivery of journey plans to a mobile device. Few journey planners are available for\\u000a urban bus travelers and tend to restrict users to a limited number of journey endpoints. This is due to the challenges

Desmond Rainsford; William A. Mackaness

2002-01-01

292

Simulation Model of Bus Rapid Transit  

NASA Astrophysics Data System (ADS)

Bus rapid transit system is modern solution for mass transportation system. The system, in comparison to the rail-based transportation system, is significantly cheaper and requires shorter development time, but lower performance. The BRT system performance strongly depends on variables related to station design and infrastructure. A numerical model offers an effective and efficient means to evaluate the system performance. This article offers a detailed numerical model on the basis of the discrete-event approach and demonstrates its application.

Gunawan, Fergyanto E.; Suharjito; Gunawan, Alexander A. S.

2014-03-01

293

A scalable priority queue manager architecture for output-buffered ATM switches  

Microsoft Academic Search

We describe a scalable priority queue manager that implements deadline-ordered service disciplines in an output-buffered ATM switch, which can be used as a switching node in high-speed packet switched networks to provide quality of service (QoS) guarantees. The priority queue manager can handle a range of priority levels from 0 to (216 -1), a buffer size of 64 k ATM

Viet L. Do; Kenneth Y. Yun

1999-01-01

294

FastForward for efficient pipeline parallelism: a cache-optimized concurrent lock-free queue  

Microsoft Academic Search

Low overhead core-to-core communication is critical for efficient pipeline-parallel software applications. This paper presents Fast- Forward, a cache-optimized single-producer\\/single-consumer con- current lock-free queue for pipeline parallelism on multicore archi- tectures, with weak to strongly ordered consistency models. En- queue and dequeue times on a 2.66 GHz Opteron 2218 based sys- tem are as low as 28.5 ns, up to 5x

John Giacomoni; Tipp Moseley; Manish Vachharajani

2008-01-01

295

A stable queue-based adaptive controller for improving AQM performance  

Microsoft Academic Search

Active queue management (AQM) mechanisms are designed to provide better support for end-to-end congestion control mechanisms of transmission control protocol (TCP) in TCP\\/IP networks. This paper introduces a stable queue-based adaptive proportional–integral (Q-SAPI) controller for AQM and presents an implementation. The starting points of our approach are the recently developed fluid-flow modeling and control theoretic interpretation of the TCP\\/AQM dynamics,

Xiaolin Chang; Jogesh K. Muppala

2006-01-01

296

GA-based PID active queue management control design for a class of TCP communication networks  

Microsoft Academic Search

Active queue management (AQM) is a key congestion control scheme for reducing packet loss and improving network utilization in TCP\\/IP networks. This paper proposes a proportional–integral-derivative (PID) controller as an active queue manager for Internet routers. Due to the limitations of packet-dropping probability and the effects of propagation delays in TCP networks, the TCP AQM network was modeled as a

Chang-kuo Chen; Hang-hong Kuo; Jun-juh Yan; Teh-lu Liao

2009-01-01

297

Design of rate-based controllers for active queue management in TCP\\/IP networks  

Microsoft Academic Search

In our previous work [J. Aweya, M. Ouellette, D. Montuno, K. Felske, Rate-based proportional-integral control scheme for active queue management, International Journal of Network Management, John Wiley & Sons, Ltd., vol. 16, issue 3, May–June 2006, pp. 203–231] we argued that rate-based active queue management (AQM) schemes are most appropriate for high speed links which, typically, have small buffers in

James Aweya; Michel Ouellette; Delfin Y. Montuno; Kent Felske

2008-01-01

298

Bayesian estimation for the M\\/ G\\/1 queue using a phase-type approximation  

Microsoft Academic Search

This article deals with Bayesian inference and prediction for M\\/G\\/1 queueing systems. The general service time density is approximated with a class of Erlang mixtures which are phase-type distributions. Given this phase-type approximation, an explicit evaluation of measures such as the stationary queue size, waiting time and busy period distributions can be obtained. Given arrival and service data, a Bayesian

M. C. Aus??n; M. P. Wiper; R. E. Lillo

2004-01-01

299

The Brownian approximation for rate-control throttles and the G\\/G\\/1\\/C queue  

Microsoft Academic Search

This paper studies approximations to describe the performance of a rate-control throttle based on a token bank, which is closely related to the standard G\\/G\\/1\\/C queue and the two-node cyclic network of ·\\/G\\/1\\/ queues. Several different approximations for the throttle are considered, but most attention is given to a Brownian or diffusion approximation. The Brownian approximation is supported by a

Arthur W. Berger; Ward Whitt

1992-01-01

300

Towards better multi-class parametric-decomposition approximations for open queueing networks  

Microsoft Academic Search

Methods are developed for approximately characterizing the departure process of each customer class from a multi-class single-server queue with unlimited waiting space and the first-in-first-out service discipline. The model is ?(GTi\\/GIi)\\/1 with a non-Poisson renewal arrival process and a non-exponential service-time distribution for each class. The methods provide a basis for improving parametric-decomposition approximations for analyzing non-Markov open queueing networks

Ward Whitt

1994-01-01

301

An overview of Brownian and non-Brownian FCLTs for the single-server queue  

Microsoft Academic Search

We review functional central limit theorems (FCLTs) for the queue-content process in a single-server queue with finite waiting room and the first-come first-served service disci- pline. We emphasize alternatives to the familiar heavy-traffic FCLTs with reflected Brownian motion (RBM) limit process that arise with heavy-tailed probability distributions and strong dependence. Just as for the familiar convergence to RBM, the alternative

Ward Whitt

2000-01-01

302

A Decomposition Procedure for the Analysis of a Closed Fork\\/Join Queueing System  

Microsoft Academic Search

An iterative approximation algorithm for analyzing a closed queueing system with a K-sibling fork\\/join queue is presented. The iterative procedure is based on a combination of nearly complete decomposability and the Gauss-Seidel method. The approximation procedure gives good results for the mean response time and the system throughput. The iterative procedure converges to the exact solution in the case of

Y. C. Liu; Harry G. Perros

1991-01-01

303

Spacecraft design project multipurpose satellite bus MPS  

NASA Technical Reports Server (NTRS)

The thrust of this project was to design not a single spacecraft, but to design a multimission bus capable of supporting several current payloads and unnamed, unspecified future payloads. Spiraling costs of spacecraft and shrinking defense budgets necessitated a fresh look at the feasibility of a multimission spacecraft bus. The design team chose two very diverse and different payloads, and along with them two vastly different orbits, to show that multimission spacecraft buses are an area where indeed more research and effort needs to be made. Tradeoffs, of course, were made throughout the design, but optimization of subsystem components limited weight and volume penalties, performance degradation, and reliability concerns. Simplicity was chosen over more complex, sophisticated and usually more efficient designs. Cost of individual subsystem components was not a primary concern in the design phase, but every effort was made to chose flight tested and flight proven hardware. Significant cost savings could be realized if a standard spacecraft bus was indeed designed and purchased in finite quantities.

Kellman, Lyle; Riley, John; Szostak, Michael; Watkins, Joseph; Willhelm, Joseph; Yale, Gary

1990-01-01

304

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

305

A Passive Transit Signal Priority Approach for Bus Rapid Transit System  

Microsoft Academic Search

The objective of Bus Signal Priority (BSP) for Bus Rapid Transit System(BRT) is not only decreasing buses delay but also enhancing the reliability of bus service by keeping buses on schedule or maintaining bus headway adherence. One problem with existing bus priority strategies is that they do not care about the variances of sequential buses delay at intersections. Usually buses

Wanjing Ma; Xiaoguang Yang

2007-01-01

306

Development of Real-Time Optimal Bus Scheduling and Headway Control Models  

Microsoft Academic Search

Infrequent bus service because of a sudden rise in international gas prices has created a significant social problem in South Korea. Bus service frequency is determined by considering bus operation costs to the service supplier, passenger demand, and so forth. Optimal bus frequency was determined and a timetable for each bus stop was created by applying the DTR (demand- and

Wongil Kim; Bongsoo Son; Jin-Hyuk Chung; Eungcheol Kim

2009-01-01

307

How long to wait?: predicting bus arrival time with mobile phone based participatory sensing  

Microsoft Academic Search

The bus arrival time is primary information to most city transport travelers. Excessively long waiting time at bus stops often discourages the travelers and makes them reluctant to take buses. In this paper, we present a bus arrival time prediction system based on bus passengers' participatory sensing. With commodity mobile phones, the bus passengers' surrounding environmental context is effectively collected

Pengfei Zhou; Yuanqing Zheng; Mo Li

2012-01-01

308

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

309

Subsidies and welfare maximization tradeoffs in bus transit systems  

Microsoft Academic Search

Under a maximum welfare objective, a fixed route bus system and a flexible route bus system are optimized subject to various\\u000a financial constraints. For each bus system, the decision variables including fare, headway, route spacing, and service zone\\u000a area are optimally solved to analyze unconstrained, break-even and subsidy cases. Numerical results and sensitivity analysis\\u000a are presented in the paper. From

Ying Zhou; Hong Sok Kim; Paul Schonfeld; Eungcheol Kim

2008-01-01

310

Evaluation of Truck and Bus Automation Scenarios: Operations Cost Analysis  

Microsoft Academic Search

Automated bus and truck systems hold the potential to improve road safety by eliminating some human error, increase the vehicle throughput by allowing vehicle convoying to shorten headways, and reduce costs associated with infrastructure, user time, and drivers. In this study, an automated bus system (ABUS) was compared with more-conventional light rail and bus-on-dedicated-lane (BDL) alternatives. A cost comparison (excluding

Jan Botha; Jennifer E. Day; Nagabhargavi Adibhatla

2004-01-01

311

An efficient bus architecture for system-on-chip design  

Microsoft Academic Search

This paper presents the issues confronted when integrating system-on-chip (SOC) designs and offers solution through a detailed description of the CoreFrameTM system-on-chip bus architecture that has dramatically reduced system design and verification effort while enhancing the reusability and customizability of system-on-chip product developments. The CoreFrame on-chip bus architecture is defined along with examples to illustrate how a design friendly bus

B. Cordan

1999-01-01

312

Use of the I2C Bus in Space Applications  

NASA Astrophysics Data System (ADS)

The two wire bidirectional I C-bus [1] has been proposed for use in space applications and the European Space Agency has recently expressed interest in evaluating I C for space sensor buses [2]. This paper contains an introduction to the I C-bus and gives an overview of its use. Additions to make the bus fault tolerant are discussed, as well as an alternative to the physical layer defined in the I C specification. The paper also describes SoC integration of I C IP cores as well as present and planned future, products from Aeroflex Gaisler that include support for the I C-bus.

Andersson, J.; Habinc, S.; Gaisler, J.; Furano, G.

2009-05-01

313

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

314

Limited-stop bus service at New York City Transit  

SciTech Connect

Improving the speed and reliability of high-volume urban bus service is an important transit planning objective. One means of increasing travel speed is to provide a limited-stop bus service component on heavily patronized local bus routes. This paper explores the characteristics of limited-stop bus service and the experiences of the Metropolitan Transit Authority (MTA)/New York City (NYC) Transit with this type of service. It also describes the key issues, factors, and customer response associated with this service strategy.

NONE

1998-11-01

315

Status of the IEEE P896 Future Backplane Bus  

SciTech Connect

The IEEE P896 Future Backplane Bus project has been influenced by and has influenced FASTBUS and several other contemporary bus designs. This paper summarizes the current status of that project, which is directed toward the needs of modern 32-bit microprocessor systems with multiple processors. Some of the technology developed for P896 will be important for future non-ECL implementations of FASTBUS and other buses. In particular, new bus drivers and receivers should greatly improve the performance and reliability of backplane buses and cable buses. The current status of the P896 serial bus is also summarized.

Gustavson, D.B.

1983-10-01

316

Bus Route Guidance Information Design: A Manual for Bus and Light Rail Transit Systems.  

National Technical Information Service (NTIS)

The design guide is for bus systems or light rail systems in locales in which a substantial number of riders are expected to be infrequent users, tourists, or transients. Fulfilling route information needs for those who are not daily commuters are of prim...

R. J. Koppa L. L. Higgins

1994-01-01

317

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

318

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

319

49 CFR 605.18 - Comments by private school bus operators.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Comments by private school bus operators. 605.18 Section 605.18 ...TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SCHOOL BUS OPERATIONS School Bus Agreements § 605.18 Comments by...

2013-10-01

320

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

Federal Register 2010, 2011, 2012, 2013

...have amended the Federal Transit Administration's (FTA's) bus testing regulation to increase...require FTA to work with bus manufacturers and transit agencies to establish a new pass/ fail standard for the bus testing program, which...

2012-12-14

321

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

Code of Federal Regulations, 2010 CFR

...Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BUS TESTING Pt. 665, App...report âFirst Article Transit Bus Test Plan,â which...Protection Agency (EPA) for transit bus emissions, plus...

2010-10-01

322

Schedule and complex motion of shuttle bus induced by periodic inflow of passengers  

NASA Astrophysics Data System (ADS)

We have studied the dynamic behavior of a bus in the shuttle bus transportation with a periodic inflow. A bus schedule is closely related to the dynamics. We present the modified circle map model for the dynamics of the shuttle bus. The motion of the shuttle bus depends on the loading parameter and the inflow period. The shuttle bus displays the periodic, quasi-periodic, and chaotic motions with varying both loading parameter and inflow rate.

Nagatani, Takashi; Naito, Yuichi

2011-09-01

323

A queueing approach to multi-site enzyme kinetics.  

PubMed

Multi-site enzymes, defined as where multiple substrate molecules can bind simultaneously to the same enzyme molecule, play a key role in a number of biological networks, with the Escherichia coli protease ClpXP a well-studied example. These enzymes can form a low latency 'waiting line' of substrate to the enzyme's catalytic core, such that the enzyme molecule can continue to collect substrate even when the catalytic core is occupied. To understand multi-site enzyme kinetics, we study a discrete stochastic model that includes a single catalytic core fed by a fixed number of substrate binding sites. A natural queueing systems analogy is found to provide substantial insight into the dynamics of the model. From this, we derive exact results for the probability distribution of the enzyme configuration and for the distribution of substrate departure times in the case of identical but distinguishable classes of substrate molecules. Comments are also provided for the case when different classes of substrate molecules are not processed identically. PMID:24904740

Hochendoner, Philip; Ogle, Curtis; Mather, William H

2014-06-01

324

Propagation speed of a starting wave in a queue of pedestrians  

NASA Astrophysics Data System (ADS)

The propagation speed of a starting wave, which is a wave of people's successive reactions in the relaxation process of a queue, has an essential role for pedestrians and vehicles to achieve smooth movement. For example, a queue of vehicles with appropriate headway (or density) alleviates traffic jams since the delay of reaction to start is minimized. In this paper, we have investigated the fundamental relation between the propagation speed of a starting wave and the initial density by both our mathematical model built on the stochastic cellular automata and experimental measurements. Analysis of our mathematical model implies that the relation is characterized by the power law ??-? (??1), and the experimental results verify this feature. Moreover, when the starting wave is characterized by the power law (?>1), we have revealed the existence of optimal density, where the required time, i.e., the sum of the waiting time until the starting wave reaches the last pedestrian in a queue and his/her travel time to pass the head position of the initial queue, is minimized. This optimal density inevitably plays a significant role in achieving a smooth movement of crowds and vehicles in a queue.

Tomoeda, Akiyasu; Yanagisawa, Daichi; Imamura, Takashi; Nishinari, Katsuhiro

2012-09-01

325

Propagation speed of a starting wave in a queue of pedestrians.  

PubMed

The propagation speed of a starting wave, which is a wave of people's successive reactions in the relaxation process of a queue, has an essential role for pedestrians and vehicles to achieve smooth movement. For example, a queue of vehicles with appropriate headway (or density) alleviates traffic jams since the delay of reaction to start is minimized. In this paper, we have investigated the fundamental relation between the propagation speed of a starting wave and the initial density by both our mathematical model built on the stochastic cellular automata and experimental measurements. Analysis of our mathematical model implies that the relation is characterized by the power law ??-? (??1), and the experimental results verify this feature. Moreover, when the starting wave is characterized by the power law (?>1), we have revealed the existence of optimal density, where the required time, i.e., the sum of the waiting time until the starting wave reaches the last pedestrian in a queue and his/her travel time to pass the head position of the initial queue, is minimized. This optimal density inevitably plays a significant role in achieving a smooth movement of crowds and vehicles in a queue. PMID:23030986

Tomoeda, Akiyasu; Yanagisawa, Daichi; Imamura, Takashi; Nishinari, Katsuhiro

2012-09-01

326

Bus driver well-being review: 50 years of research  

Microsoft Academic Search

This review paper consolidates the key research on the occupational health of urban bus drivers since the 1950s. Several electronic databases were searched and 27 key studies were identified, which form the basis of this paper. Early findings that bus drivers are liable to suffer ill health as a result of the job remain true today. The research has, however,

John L. M. Tse; Rhona Flin; Kathryn Mearns

2006-01-01

327

Bus-based best-practice and urban transport emissions  

NASA Astrophysics Data System (ADS)

In Britain over recent years, transport has risen to the very top of the political agenda, partly because it is the fastest growing source of urban emissions. One politically attractive solution to this rapidly worsening problem, is 'improving public transport'. This thesis examines how the bus-the most widespread form of public transport-could be improved, and at how much these improvements would contribute to solving the emissions problem. The project was studied in two inter-related parts. The first part aimed to determine the factors necessary in forming the 'best possible' bus-based transport system by identifying and analysing a number of 'best-practice' bus systems in Europe and North America, using a case study approach. The second part then sought to quantify the effect on travel patterns and emissions that implementing this best possible bus-based transport system would have. This was done by modelling a series of possible scenarios with the START strategic transport model, and a modified version of the JET emissions inventory model. The City of Leicester was used as a modelling base. The study found that bus systems contributed most to reducing urban emissions where the needs of the bus passenger were made paramount, and where bus operators worked together with local government, local businesses etc. Even where these factors existed however, the effect of bus-based transport policies on levels of pollutants was found to be significant only when applied together with strong car restraint measures.

Enoch, Marcus Paul

328

Analysis of an Audio Control Protocol with Bus Collision  

Microsoft Academic Search

We analyze the data link layer of a protocol developed by Philips toconnect the devices of an audio set. The protocol allows significant timeuncertainty, and because several componets are conected to one bus theprotocol has to deal with bus collisions. Besides a proof of correctness themaximal tolerance on timing for which the protocol still functions correctlyis given. For the verification

W. o. d. Griffioen

1994-01-01

329

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

330

Preliminary Evaluation of Metro Orange Line Bus Rapid Transit Project  

Microsoft Academic Search

This paper provides a preliminary assessment of the Metro Orange Line of Los Angeles County, California, one of the first full-feature bus rapid transit (BRT) systems in the United States. The paper also compares the Orange Line with two recent transit investments in Los Angeles: the Gold Line light rail and Metro Rapid, a rapid bus service with limited BRT

Lisa Callaghan; William Vincent

2007-01-01

331

BUS RAPID TRANSIT TECHNOLOGIES IN THE AMERICAS: AN OVERVIEW  

Microsoft Academic Search

Results from a survey of international bus rapid transit (BRT) systems reveal a wide range of technology options for implementing a BRT system. Eight BRT systems (seven existing and one under development) in North and South America demonstrate innovative applications of five bus technology components--vehicles, guideways and stations, control systems (dispatching and signaling), fare systems, and passenger information systems. These

Roderick Diaz; Donald Schneck

2000-01-01

332

Delay at signal-controlled intersection with bus stop upstream  

SciTech Connect

Because of the tight constraints on many streets in urban areas, it is not uncommon to situate a bus stop upstream of a signal-controlled intersection without the provision of a proper bus bay or setback. For a single-lane approach, where the overtaking of a stopped bus at the bus stop is prohibited, the setup of such a bus stop would significantly affect the delay incurred by road users. It is believed that the delay in such situations depends on a number of factors, such as the distance between bus stop and stop line, traffic and bus flows, dwell time of buses and signal settings. In this paper, a simulation model for estimating the delay on an approach to a signal-controlled intersection with a bus stop upstream is developed. To test the reliability of the model, field surveys were conducted to validate the simulation model. A good agreement between the observed and simulation results was obtained. When the simulation model was used, a new delay formula was established and calibrated for use in the design of a signal-controlled intersection.

Wong, S.C.; Yeung, W.S.A.; Cheuk, S.L.; Lo, M.K. [Univ. of Hong Kong (Hong Kong). Dept. of Civil and Structural Engineering; Yang, H. [Hong Kong Univ. of Science and Technology, Clear Water Bay (Hong Kong)

1998-05-01

333

Cost Functions and Efficiency Estimates of Midwest Bus Transit Systems  

Microsoft Academic Search

Short-run variable cost functions are estimated with the use of a sample of 68 bus systems in the U.S. Midwest operating in the 1996 to 2002 period. Variable costs are specified as functions of outputs, input prices, bus stocks, and network size. Various output, input price, network, capacity, and disturbance specifications are examined. The cost functions are estimated with the

Donald J Harmatuck

2005-01-01

334

BUS RAPID TRANSIT: AN ALTERNATIVE FOR DEVELOPING COUNTRIES  

Microsoft Academic Search

Bus Rapid Transit (BRT) combines the benefits of light rail transit with the flexibility and efficiency of bus transit. The goal of BRT development is to enhance ridership and reduce operating costs with increased service levels and quality. A BRT system combines the technology of intelligent transportation systems, traffic signal priority, cleaner and quieter vehicles, rapid and convenient fare collection,

Monica T. Leal; Robert L. Bertini

335

Optimal Bus Stop Spacing for Minimizing Transit Operation Cost  

Microsoft Academic Search

With the increasing attention to finance issues relative to transit operation, a bus stop spacing model is generated with the aim at minimizing the operation cost without impact on transit accessibility. Two cost functions are considered in the model including passenger access cost and in-vehicle passenger stopping cost aiming at minimizing total cost. A bus route in Portland, Oregon, USA

Huan Li; Robert L. Bertini

336

Understanding ridership drivers for bus rapid transit systems in Australia  

Microsoft Academic Search

Bus Rapid Transit (BRT) systems are an increasingly popular public transport option in Australia and internationally. They provide rail-like quality for bus services for a fraction of the cost of fixed rail. Many claims of high and increasing ridership have resulted from BRT system development; however it is unclear exactly which aspects of BRT system design drive this.This paper undertakes

Graham Currie; Alexa Delbosc

2010-01-01

337

Rural Transport Experiments: The Exe Valley Market Bus.  

National Technical Information Service (NTIS)

The Exe Valley Market Bus in one of the Government's programm of Rural Transport Experiments (RUTEX). It serves an area to the north-west of Tiverton in Devon, where two conventional bus services were withdrawn because they were too uneconomic for local a...

1978-01-01

338

MICROSCOPIC MODELLING OF TRAFFIC MANAGEMENT MEASURES FOR GUIDED BUS OPERATION  

Microsoft Academic Search

Guided bus systems are increasingly appreciated as a cost effective method of luring travellers from private to public transport. This paper describes the developments made to enhance a traffic microsimulation model in order to help design and evaluate guided bus schemes and the complex traffic management issues which such systems present. The model framework is illustrated through numerical experiments on

RONGHUI LIU; STEPHEN CLARK; FRANK MONTGOMERY; DAVID WATLING

339

Baltimore feeder-bus planning study. Final report  

SciTech Connect

The study reviews the process used by Maryland's Mass Transit Administration to plan the feeder-bus services for Baltimore's rapid rail line. It documents the procedures used in planning the bus operations and compares the projected patronage and cost characteristics of the services to those which were actually achieved.

Not Available

1986-09-01

340

Bus Arrival Time Prediction Using Support Vector Machines  

Microsoft Academic Search

Effective prediction of bus arrival time is central to many advanced traveler information systems. This article presents support vector machines (SVM), a new neural network algorithm, to predict bus arrival time. The objective of this paper is to examine the feasibility and applicability of SVM in vehicle travel time forecasting area. Segment, the travel time of current segment, and the

Yu Bin; Yang Zhongzhen; Yao Baozhen

2006-01-01

341

Bus-Type Home Control System Using Coaxial Cables.  

National Technical Information Service (NTIS)

A home control system using coaxial cables for a home bus has been developed. The system, which employs the home bus type, is equipped with various kinds of home automation (HA) controllers (home security controller, TV adapter type HA controller, etc.) f...

T. Saka T. Kobayashi S. Nagamoto K. Nishii T. Hirose

1986-01-01

342

Indoor Air Quality and Occupational Exposures at a Bus Terminal  

Microsoft Academic Search

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

Mutasem El-Fadel; Nisrine El-Hougeiri

2003-01-01

343

Broome County Bus Transit Study. Evaluation, Analysis and Recommendations.  

National Technical Information Service (NTIS)

The report is an integration of three studies on the county bus system, giving a summary of the technical aspects, the economic potentials, and the social implications of the public bus transit system in Broome County. The findings constitute a data resou...

1968-01-01

344

Simulation of uniform bus alignment satellite power system  

Microsoft Academic Search

The model of uniform bus alignment satellite power system, which based on Simulink technology, Adopts Three-Domain control, considers the influence to the power system by the output of solar array and different load., computes the energy changing, simulate the uniform bus alignment satellite power system and energy balance, gives the result. The result of simulation indicates that the high current\\/small

Fan Li; Yanjia Li; Jianhui Zhao; Xinlin Yang

2008-01-01

345

HYDROGEN-FUELED BUSES: THE BAVARIAN FUEL CELL BUS PROJECT  

Microsoft Academic Search

The goal of the project was to build and operate a prototype fuel-cell powered city bus in public revenue service. The bus was equipped with proton exchange membrane fuel cells (PEMFC) and an onboard compressed hydrogen storage system. The integration of a new power train and fuel storage and supply system should provide new experiences with respect to system integration

Christian Gruber; Munich Reinhold Wurster

346

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

347

Coordinated Optimization of Bus Headways for Passenger Corridors  

Microsoft Academic Search

Passenger corridors carry high-density passenger volumes and they are intensive superposition sections of passenger OD demands in the transit network. In order to balance supply and demand distribution between different bus routes on the same passenger corridor, the optimization methodology of headways need be studied. This paper set up a bus coordination dispatching model for passenger corridors and then applied

Jing Teng; Xiaoguang Yang; Xuan Li; Ming Zhao

2009-01-01

348

Bus Passenger Origin-Destination Estimation and Related Analyses  

Microsoft Academic Search

This research explores the application of archived data from Automated Data Collection Systems (ADCS) to transport planning with a focus on bus passenger travel behavior, including Origin-Destination (OD) inference, using London as a case study. It demonstrates the feasibility and ease of applying trip-chaining to infer bus passenger OD from smart card transactions and Automatic Vehicle Location (AVL) data and

Wei Wang; John P Attanucci; Nigel H. M. Wilson

2011-01-01

349

Estimating additional capacity requirements due to free bus travel  

Microsoft Academic Search

The UK has recently seen a spike in interest in the issue of what the appropriate level of operator reimbursement should be for the carriage of concessionary bus passengers. This has come about largely as the result of the introduction of a national entitlement to free bus travel for elderly and disable passengers, first in Scotland and Wales, and more

Pedro Abrantes; Andrew Last

2011-01-01

350

An Investigation of a Battery-Trolley Bus System.  

National Technical Information Service (NTIS)

A feasibility study of a combined battery and trolley bus system has been carried out. The double-decked 80-passenger electric bus has a performance compatible with modern traffic. It is powered from overhead wires for only part of its route. For the rema...

R. Weeks

1978-01-01

351

Connecticut Transit (CTTRANSIT) Fuel Cell Transit Bus: Third Evaluation Report.  

National Technical Information Service (NTIS)

This report describes operations at Connecticut Transit (CTTRANSIT) in Hartford for one prototype fuel cell bus and three newer diesel buses operating from the same location. The prototype fuel cell bus was manufactured by Van Hool and ISE Corp. and featu...

K. Chandler L. Eudy

2010-01-01

352

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

353

Small aircraft avionics using hybrid data bus technology  

Microsoft Academic Search

This paper presents a recent study of avionics system design and implementation for small aircraft. Avionic system is one of the most important systems to all kinds of aircraft. For digital avionics system integration, a hybrid data bus is proposed in this development. The proposed hybrid data bus (HDB) adopts some characteristics from time trigger protocol (TTP) in conjunction with

C. E. Lin; S. F. Tai; C. C. Li; H. T. Lin; T. P. Chen

2006-01-01

354

OPTIMAL BUS STOP SPACING THROUGH DYNAMIC PROGRAMMING AND GEOGRAPHIC MODELING  

Microsoft Academic Search

A discrete approach was used to model the impacts of changing bus-stop spacing on a bus route. Among the impacts were delays to through riders, increased operating cost because of stopping delays, and shorter walking times perpendicular to the route. Every intersection along the route was treated as a candidate stop location. A simple geographic model was used to distribute

Peter G Furth; Adam B Rahbee

2000-01-01

355

Characterizing bus transit passenger wait times. Research report  

SciTech Connect

Mathematical models are developed to predict bus passenger waiting time components. A statistically significant quantity of waiting time data, including related passenger attributes, transits system characteristics and bus frequency, were collected by direct observation and video taping. The experimental data were collected in a six-month period at several bus transfer centers and bus stations in the city of Austin, Texas. Measured wait time was decomposed into two components: `wait time before scheduled departure time` and `wait time after scheduled departure time.` The effects of bus frequency and reliability, as well as other potential predictors on wait time components, were examined by performing Analysis of Variance and Regression. Traditional and conceptual waiting time models were evaluated using this data set and compared to the new developed models.

Salek, M.D.; Machemehl, R.B.

1999-06-01

356

Regenerative polymeric bus architecture for board-level optical interconnects.  

PubMed

A scalable multi-channel optical regenerative bus architecture based on the use of polymer waveguides is presented for the first time. The architecture offers high-speed interconnection between electrical cards allowing regenerative bus extension with multiple segments and therefore connection of an arbitrary number of cards onto the bus. In a proof-of-principle demonstration, a 4-channel 3-card polymeric bus module is designed and fabricated on standard FR4 substrates. Low insertion losses (? -15 dB) and low crosstalk values (< -30 dB) are achieved for the fabricated samples while better than ± 6 µm -1 dB alignment tolerances are obtained. 10 Gb/s data communication with a bit-error-rate (BER) lower than 10(-12) is demonstrated for the first time between card interfaces on two different bus modules using a prototype 3R regenerator. PMID:22714148

Bamiedakis, N; Hashim, A; Penty, R V; White, I H

2012-05-21

357

On the implementation of a smoothed perturbation analysis estimator for a single-server queue with multiple vacations  

Microsoft Academic Search

We consider applying perturbation analysis (PA) to a single-server queue with multiple server vacations. A major difficulty in the implementation of a PA estimator for such queueing systems is that the introduced perturbations are propagated and accumulated continuously without any resetting. This fact may lead to the divergence of PA estimates even if the limiting distribution exists. We show that

Takayuki Takagi; Naoto Miyoshi

1999-01-01

358

Stochastic Processes Occurring in the Theory of Queues and their Analysis by the Method of the Imbedded Markov Chain  

Microsoft Academic Search

The stochastic processes which occur in the theory of queues are in general not Markovian and special methods are required for their analysis. In many cases the problem can be greatly simplified by restricting attention to an imbedded Markov chain. In this paper some recent work on single-server queues is first reviewed from this standpoint, and the method is then

David G. Kendall

1953-01-01

359

USING TOKEN LEAKY BUCKETS FOR CONGESTION FEEDBACK CONTROL IN PACKETS SWITCHED NETWORKS WITH GUARANTEED BOUNDEDNESS OF BUFFER QUEUES  

Microsoft Academic Search

A fluid flow model of a FIFO queueing system is presented and extended to the so-called token leaky bucket case. A sim- ple feedback strategy that guarantees the boundedness of pack- ets buffer queue is then introduced. Some simulations are pre- sented and confronted to experiments run on a network made of Linux machines.

V. Guffens; G. Bastin; H. Mounier

360

Dual inclusion principle for dual systems  

Microsoft Academic Search

A dual inclusion is defined for dual systems in this paper. For restriction and aggregation as special inclusion cases, their dual relationships of inclusion conditions between the original system and its dual system are derived. It is shown that, in the expansions of both original and its dual overlapping interconnected systems, only one case of restriction or aggregation conditions is

Xue-Bo Chen; Srdjan S. Stankovic

2002-01-01

361

Knowledge, Attitude and Practices of Food Handlers at Bus Terminals in the Bangkok Mass Transit Authority Bus Zone7 ??????? ??????? ?????????????????????????????? ??????????? ???????????????????????? ??????????????? 7 ???? ???????????* ?????? ???????????* ???????? ?????* ?????? ????????????** ?????? ?????????* ??? ?????? ????????  

Microsoft Academic Search

Our previous paper concerning the surveying of food shops in the Bangkok Mass Transit Authority bus zone 7 showed that poor personal hygiene and behavior of food handlers are important factors that may be contributing factors for diarrhea and food poisoning of bus drivers. This study was aimed at examining food sanitation conditions and knowledge, attitude and practices of food

Danaya Wongsirikul; Suthida Chongpiyawarang; Duangrat Inthorn; Bhusita Intaraprasong; Chatchawal Singhakant; Orawan Kaewboonchoo

362

Optimal Service Capacities in a Competitive Multiple-Server Queueing Environment  

NASA Astrophysics Data System (ADS)

The study of economic behavior of service providers in a competition environment is an important and interesting research issue. A two-server queueing model has been proposed in Kalai et al. [11] for this purpose. Their model aims at studying the role and impact of service capacity in capturing larger market share so as to maximize the long-run expected profit. They formulate the problem as a two-person strategic game and analyze the equilibrium solutions. The main aim of this paper is to extend the results of the two-server queueing model in [11] to the case of multiple servers. We will only focus on the case when the queueing system is stable.

Ching, Wai-Ki; Choi, Sin-Man; Huang, Min

363

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

364

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

365

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

366

Dynamic multi-interval bus travel time prediction using bus transit data  

Microsoft Academic Search

The objective of this research is to develop a dynamic model to forecast multi-interval path travel times between bus stops of origin and destination. The research also intends to test the proposed model using real-world data. This research was brought about by the shortcomings of the existing real-time based short-term-prediction models, which have been widely utilised for single interval predictions.

Hyunho Chang; Seungjae Lee; Hosang Lee; Seungkirl Baek

2010-01-01

367

Evaluation of the benefits of using dual-source energy storage in hybrid electric vehicles  

Microsoft Academic Search

Batteries are often used as energy storage in hybrid and electric vehicles. Despite of the development, technical characteristics of batteries are the most limiting factor for further increasing the energy conversion efficiency and pure electric operation of these vehicles. In this research, dual-source energy storage system, a battery pack and ultracapacitors, has been studied by simulation of hybrid city bus

Antti Lajunen

2010-01-01

368

An overview of Brownian and non-Brownian FCLTs for the single-server queue  

Microsoft Academic Search

We review functional central limit theorems (FCLTs) for the queue-content process in a single-server queue with finite waiting\\u000a room and the first-come first-served service discipline. We emphasize alternatives to the familiar heavy-traffic FCLTs with\\u000a reflected Brownian motion (RBM) limit process that arise with heavy-tailed probability distributions and strong dependence.\\u000a Just as for the familiar convergence to RBM, the alternative FCLTs

Ward Whitt

2000-01-01

369

Bus bar electrical feedthrough for electrorefiner system  

DOEpatents

A bus bar electrical feedthrough for an electrorefiner system may include a retaining plate, electrical isolator, and/or contact block. The retaining plate may include a central opening. The electrical isolator may include a top portion, a base portion, and a slot extending through the top and base portions. The top portion of the electrical isolator may be configured to extend through the central opening of the retaining plate. The contact block may include an upper section, a lower section, and a ridge separating the upper and lower sections. The upper section of the contact block may be configured to extend through the slot of the electrical isolator and the central opening of the retaining plate. Accordingly, relatively high electrical currents may be transferred into a glovebox or hot-cell facility at a relatively low cost and higher amperage capacity without sacrificing atmosphere integrity.

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

2013-12-03

370

Automobile, Bus, and Rail Passenger Air Quality  

Microsoft Academic Search

Concentrations of pollutants emitted in the exhaust of gasoline and diesel engines and from\\u000a evaporation of fuels -- (e.g. CO, CO2, NO\\u000a \\u0009\\u0009\\u0009\\u0009\\u0009\\u0009\\u0009\\u0009x\\u000a \\u0009\\u0009\\u0009\\u0009\\u0009\\u0009\\u0009,\\u000a particulate matter, and volatile organic compounds) have been measured at elevated levels within the\\u000a enclosed spaces of automobile, bus, and train cabins in urban centers throughout the world and compared\\u000a to ambient air levels. The magnitude

Clifford P. Weisel

371

Coronary heart disease risk factors in urban bus drivers.  

PubMed

The purpose of this study was to determine the risk factors for coronary heart disease (CHD) in 2297 bus drivers and skilled workers from the Taipei Municipal Bus Administrative Bureau. Data for this study were compiled from the medical records of annual physical examinations for bus drivers and skilled workers conducted at Taipei Municipal Chronic Disease Hospital during the period from July 1998 to June 1999. The results showed that, after adjustment for age, hypertension rates for bus drivers (56.0%, 986/1361) were significantly greater than for skilled workers (30.6%, 164/536). All age groups demonstrated a similar difference. Significant differences were also noted in body mass index, serum cholesterol, serum triglyceride and ischemic heart disease between bus drivers and skilled workers. Among bus drivers, the prevalence of obesity was 9.6%, hypercholesterolemia 34.0%, hypertriglyceridemia 69.4% and ischemic heart disease 1.7%. By contrast, among skilled workers, the prevalence of obesity was only 4.6%, hypercholesterolemia 29.9%, hypertriglyceridemia 30.6% and ischemic heart disease 0.9%. These findings suggest that exposure to the occupation of driving a bus may carry an increased risk of CHD and that drivers who develop signs of cardiovascular illness should be transferred to non-driving occupations within the company. PMID:11464297

Wang, P D; Lin, R S

2001-07-01

372

Observability Analysis Of Large Bus - System Using Matlab Simulation  

NASA Astrophysics Data System (ADS)

This methodology provides a numerical approach to observability analysis. The approach enables observability analysis and restoration (pseudo-measurement selection) in a simple way with iteration, via triangular factorization of the jacobian matrix of the weight least square state estimator. An algorithm for precious measurement of topological observability in large bus - system state estimation has been proposed. The algorithm is based on observation that the search for a spanning tree of full rank. We use observability algorithm and state estimation algorithm. We use the Mat lab to obtain the various graphs of bus systems. By using simulation method of bus system we analyze the observability.

Gyanendrasingh, Er.; Pratibhatiwari, Prashant Kumar; Srivastava, Tushar

2013-03-01

373

Dual Billiards.  

National Technical Information Service (NTIS)

Given a smooth strictly convex curve in the plane, one defines the dual billiard map in its exterior in the following way. Call the curve gamma and let x be a point outside of it. There exist two tangent lines to gamma through x; choose one of them, say, ...

S. Tabachnikov

1992-01-01

374

Dual photography  

Microsoft Academic Search

We present a novel photographic technique called dual photography, which exploits Helmholtz reciprocity to interchange the lights and cameras in a scene. With a video projector providing structured illumination, reciprocity permits us to generate pictures from the viewpoint of the projector, even though no camera was present at that location. The technique is completely image-based, requiring no knowledge of scene

Pradeep Sen; Billy Chen; Gaurav Garg; Stephen R. Marschner; Mark Horowitz; Marc Levoy; Hendrik P. A. Lensch

2005-01-01

375

The workload in the MAP\\/G\\/1 queue with state-dependent services:its application to a queue with preemptive resume priority  

Microsoft Academic Search

In this paper, we consider the workload process in the MAP\\/G\\/1 queue with state-dependent service time distributions. The arrival process of customers is assumed to be a MAP(Markovian arrival process), which is a class of semi-Markovian arrival processes. The amount of work brought into the system upon arrival is distributed according to a general distribution which may depend on the

Tetsuya Takine; T. Hasegawa

1994-01-01

376

A novel GIS-based decision-making framework for the school bus routing problem  

Microsoft Academic Search

The school bus routing problem (SBRP) is a central issue in transportation planning and optimization systems. SBRP seeks to plan an efficient schedule for a fleet of school buses where each bus picks up students from various bus stops and delivers them to their designated schools while satisfying various constraints such as the maximum capacity of a bus, and the

Khalid A. ELDRANDALY; AbdelMonaem F. ABDALLAH

2012-01-01

377

On timing constraints of snooping in a bus-based COMA multiprocessor 1  

Microsoft Academic Search

Cache only memory architecture has the potential to decrease global bus traffic in shared-bus multiprocessors, thereby reducing the speed gap between modem microprocessors and global backplane bus systems. However, the (huge) size of attraction memory (AM) in each processor node makes it difficult to properly match the access time of its state and tag storage to the bus cycle. This

Sangyeun Cho; Jinseok Kong; Gyungho Lee

378

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.

379

49 CFR 605.18 - Comments by private school bus operators.  

Code of Federal Regulations, 2010 CFR

...Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT...TRANSPORTATION SCHOOL BUS OPERATIONS School Bus...proposed or existing school bus operations at the time...of the Federal Mass Transit Act of 1964, as amended...comments of private school bus operators must be...

2009-10-01

380

49 CFR 605.18 - Comments by private school bus operators.  

Code of Federal Regulations, 2010 CFR

...Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT...TRANSPORTATION SCHOOL BUS OPERATIONS School Bus...proposed or existing school bus operations at the time...of the Federal Mass Transit Act of 1964, as amended...comments of private school bus operators must be...

2010-10-01

381

Bus drivers' mental conditions and their relation to bus passengers' accidents with a focus on the psychological stress concept.  

PubMed

The purpose of this study was to clarify the psychological factors of bus drivers' instability that were related to bus passengers' accidents according to the hypothesis model based on the stress concept of Lazarus and Folkman (1984). This research was carried out in 2006. Participants of the study were 39 Japanese male bus drivers. Their average age was 40.2 (SD: 11.1). The average duration of employment was 4.5 (SD:6.1) years. A questionnaire was used that was composed of items concerning the frequency of bus passengers' accidents, performance of safe driving, job stressors, stress reaction and recognition from others. Based on the results, a model assuming that stress reaction caused by job stressors disturbed the bus driver's safe driving and was associated with passengers' accidents in the bus was verified to some degree. Especially, melancholy and tired feeling toward passengers showed a strong relation to the passengers' accidents in the bus. This suggested much room for intervention. Moreover, the recognition from others of their job was confirmed to act as a control factor of the stress reaction. PMID:19157155

Yamada, Yasuyuki; Mizuno, Motoki; Sugiura, Miyuki; Tanaka, Sumio; Mizuno, Yuki; Yanagiya, Toshio; Hirosawa, Masataka

2008-06-01

382

Virtual Queueing Techniques for ABR Service: Improving ABR\\/VBR Interaction  

Microsoft Academic Search

Abstract Several algorithms have been proposed for the switch behavior for congestion control of Available Bit Rate (ABR) services Schemes such as the Enhanced Proportional Rate Control Algorithm (EPRCA) and the Dynamic Max Rate Control Algorithm (DMRCA), which use the queue length as congestion indicator to make a simple approximation of the fair share converge to the actual fair share,

Fabio M. Chiussi; Ye Xia; Vijay P. Kumar

1997-01-01

383

A variable structure control approach to active queue management for TCP with ECN  

Microsoft Academic Search

It has been shown that the transmission control protocol (TCP) connections through the congested routers can be modeled as a feedback dynamic system. In this paper, we design a variable structure (VS) based control scheme in active queue management (AQM) supporting explicit congestion notification (ECN). By analyzing the robustness and performance of the control scheme for the nonlinear TCP\\/AQM model,

Peng Yan; Yuan Gao; Hitay Özbay

2005-01-01

384

AFRED: An Adaptive Fuzzy-based Control Algorithm for Active Queue Management  

Microsoft Academic Search

This paper studies the active queue management (AQM) in high-speed routers. One of the original and popularly implemented AQM algorithms is random early detection (RED). But it is hard to configure the parameters involved in RED. Although there are some new TCP-modeling based approaches to overcome this, they really show some instability under such dynamical environments with diverse connections (adaptive

Chonggang Wang; Bo Li; Kazem Sohraby; Yong Peng

2003-01-01

385

Variable Structure Control in Active Queue Management for TCP with ECN  

Microsoft Academic Search

It has been shown that the TCP connections through the congested routers can be modeled as a feedback dynamic system. In this paper, we design a variable structure (VS) based control scheme in active queue management (AQM) supporting explicit congestion notification (ECN). By analyzing the robustness and performance of the control scheme for nonlinear TCP\\/AQM model, we show that the

Peng Yan; Yuan Gao; Hitay Özbay

2003-01-01

386

The Effects of Active Queue Management and Explicit Congestion Notification on Web Performance  

Microsoft Academic Search

We present an empirical study of the effects of active queue man- agement (AQM) and explicit congestion notification (ECN) on the distribution of response times experienced by a population of users browsing the Web. Three prominent AQM schemes are consid- ered: the Proportional Integral (PI) controller, the Random Expo- nential Marking (REM) controller, and Adaptive Random Early Detection (ARED). The

Le Jay; Aikat Kevin; Jeffay F. Donelson Smith

387

Predictive functional control for active queue management in congested TCP\\/IP networks  

Microsoft Academic Search

Predictive functional control (PFC) as a new active queue management (AQM) method in dynamic TCP networks supporting explicit congestion notification (ECN) is proposed. The ability of the controller in handling system delay along with its simplicity and low computational load makes PFC a privileged AQM method in the high speed networks. Besides, considering the disturbance term (which represents model\\/process mismatches,

N. Bigdeli; M. Haeri

2009-01-01

388

Gain Adaptive Smith Predictor for Congestion Control in Robust Active Queue Management  

Microsoft Academic Search

Active queue management (AQM) policies provide an early indication of incipient congestion to the source. In this paper, in terms of Lyapunov asymptotic stability principle, a robust AQM algorithm based on the gain adaptive Smith predictor and PI controller (GAS-PI algorithm) is designed by using the linearized TCP model with time delays. With the simple structure, good robustness and better

Shaohua Xiang; Bugong Xu; Sai Wu; Dazhou Peng

2006-01-01

389

A robust active queue management scheme based on global sliding mode control  

Microsoft Academic Search

For the problem of transmission control protocol (TCP) network congestion control, on the basis of global sliding mode control, an active queue management (AQM) scheme adaptive to the change of dynamic network flow is presented. The proposed scheme can eliminate the reaching phase from conventional sliding mode control, and guarantee the system robustness during the whole control process. At the

Hongwei Wang; Georgi M. Dimirovski; Yuanwei Jing; Zhaona Chen

2008-01-01

390

The effects of active queue management and explicit congestion notification on web performance  

Microsoft Academic Search

We present an empirical study of the effects of active queue management (AQM) and explicit congestion notification (ECN) on the distribution of response times experienced by users browsing the Web. Three prominent AQM designs are considered: the Proportional Integral (PI) controller, the Random Exponential Marking (REM) controller, and Adaptive Random Early Detection (ARED). The effects of these AQM designs were

Long Le; Jay Aikat; Kevin Jeffay; F. Donelson Smith

2007-01-01

391

The effects of active queue management and explicit congestion notification on web performance  

Microsoft Academic Search

We present an empirical study of the effects of ac- tive queue management (AQM) and explicit congestion notification (ECN) on the distribution of response times experienced by users browsing the Web. Three prominent AQM designs are considered: the Proportional Integral (PI) controller, the Random Exponential Marking (REM) controller, and Adaptive Random Early Detec- tion (ARED). The effects of these AQM

Long Le; Jay Aikat; Kevin Jeffay; F. Donelson Smith

2007-01-01

392

Workforce configuration and workflow analysis of an information technology organization: a queueing network approach  

Microsoft Academic Search

This paper addresses two issues related to a hypothetical division in the Canadian Forces Geomatics Organization, which is devoted to the production of information in support of the U.S. National Imaging and Mapping Agency's (NIMA) Foundation Based Operations. First, the optimal configuration of the division is determined using queueing network and optimization principles. The second issue concerns the examination of

Kevin Y. K. Ng; Ahmed Ghanmi; M. Natalie Lam; Roy E. Mitchell

2002-01-01

393

The M\\/G\\/1 retrial queue with feedback and starting failures  

Microsoft Academic Search

This paper discusses a retrial queue with Bernoulli feedback, where the server is subjected to starting failure. The retrial time is assumed to follow an arbitrary distribution and the customers in the orbit access the server under FCFS discipline. The necessary and sufficient condition for the stability of the system is derived. Various performance measures are obtained. Some numerical results

B. Krishna Kumar; S. Pavai Madheswari; A. Vijayakumar

2002-01-01

394

Design Of Filter Thickness Based On The Application Of Queueing Theory  

Microsoft Academic Search

The random movement of washed out base particles in a filter and its clogging are treated as a stochastic process. Based on a queueing model, two equations are developed to determine the mean and variance of the washed out particles into a filter under steady state condition. The filter thickness is determined from the computed mean and standard deviation of

V. Thanikachalam; R. Sakthivadivel

1975-01-01

395

Congestion Pricing and Capacity of Large Hub Airports: A Bottleneck Model with Stochastic Queues  

Microsoft Academic Search

This paper models and estimates congestion prices and capacity for large hub airports with stochastic queues, time-varying traffic rates, and endogenous intertemporal adjustment of traffic in response to queuing delay and fees. Relative costs of queuing and schedule delays are estimated using data from Minneapolis-St. Paul. Simulations calculate equilibrium traffic patterns, queuing delays, schedule delays, congestion fees, airport revenues, airport

Joseph I. Daniel

1995-01-01

396

Isolated ramp metering feedback control utilizing mixed sensitivity for desired mainline density and ramp queues  

NASA Astrophysics Data System (ADS)

This paper presents a feedback control design for isolated ramp metering control. This feedback control design, unlike the existing isolated feedback ramp controllers, also takes into account the ramp queue length. Using a nonlinear H(infinity) control design methodology, we formulate the problem in the desired setting to be able to utilize the results of the methodology.

Kachroo, Pushkin; Rakha, Hesham

1999-01-01

397

Modeling uncertainties in aggregated thermostatically controlled loads using a State queueing model  

Microsoft Academic Search

To study the impacts of price responsive demand on the electric power system requires better load models. This paper discusses the modeling of uncertainties in aggregated thermostatically controlled loads using a state queueing (SQ) model. The cycling times of thermostatically controlled appliances (TCAs) vary with the TCA types and sizes, as well as the ambient temperatures. The random consumption of

Ning Lu; David P. Chassin; Steven E. Widergren

2005-01-01

398

Modeling Supervisory Control in the Air Defense Warfare Domain with Queueing Theory.  

National Technical Information Service (NTIS)

In this paper, we hypothesize that the performance of a supervisory control operator that must process tasks recommended by a system task manager is analogous to the performance of a vacationing server, M/Er/1 queue. Thus, we assume that the input process...

G. Osga J. DiVita R. Morris

2005-01-01

399

An efficient algorithm for the exact analysis of multiclass queueing networks with large population sizes  

Microsoft Academic Search

We introduce an e-cient algorithm for the exact analysis of closed multiclass product-form queueing network models with large population sizes. We adopt a novel approach, based on linear systems of equations, which signiflcantly re- duces the cost of computing normalizing constants. With the proposed algorithm, the analysis of a model with N circulating jobs of multiple classes requires essentially the

Giuliano Casale

2006-01-01

400

An active queue management scheme based on a capture-recapture model  

Microsoft Academic Search

One of the challenges in the design of switches\\/routers is the efficient and fair use of the shared bottleneck bandwidth among different Internet flows. In particular, various active queue management (AQM) schemes have been developed to regulate transmission control protocol traffic in response to router congestion. In addition, in order to provide fair bandwidth sharing, these AQM must protect the

Ming-Kit Chan; Mounir Hamdi

2003-01-01

401

Investigating dependence in packet queues with the index of dispersion for work  

Microsoft Academic Search

The authors continue an investigation of the way diverse traffic from different data applications affects the performance of packet queues. This traffic often exhibits significant dependence among successive interarrival times, among successive service times, and between interarrival times and service times, which can cause a significant degradation of performance under heavy loads (and often even under moderate loads). This dependence

Kerry W. Fendick; Vikram R. Saksena; Ward Whitt

1991-01-01

402

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

403

Customer recall of promotional displays at supermarket checkouts: arousal, memory and waiting in queues  

Microsoft Academic Search

Three hundred and twenty shoppers were questioned about their recall of posters and magazines displayed around supermarket checkouts. High levels of recall were noted, suggesting that checkout advertising can be an extremely useful marketing weapon. Respondents were also asked to indicate the degrees of frustration, anger, stress and upset they felt while waiting in checkout queues. This information was used

Roger Bennett

1998-01-01

404

Queues, customer characteristics and policies for managing waiting-lines in supermarkets  

Microsoft Academic Search

Shoppers leaving four supermarket outlets (two in one of London’s most prosperous boroughs and two in London’s poorest) were questioned about their attitudes towards having to wait in queues, including express checkout lines. The list of interview questions incorporated items designed to assess whether customers possessed Type A or Type B personality traits. It emerged that although Type A inclination

Roger Bennett

1998-01-01

405

Optimum and equilibrium in a transport problem with queue penalization effect  

Microsoft Academic Search

Consider a distribution of citizens in an urban area in which some services (super- markets, post offices. ..) are present. Each citizen, in orderto use a service, spends an amount of time which is due both to the travel time to the service and to the queue time waiting in the service. The choice of the service to be used

Gianluca Crippa; CHLO ´ E JIMENEZ; Aldo Pratelli

2009-01-01

406

A Manager-Friendly Platform for Simulation Modeling and Analysis of Call Center Queueing Systems  

Microsoft Academic Search

Call center operational performance is measured largely through queue times and customer abandonment rates, and thus managers have an acute need to understand how both management policies and stochastic factors affect these performance statistics. Simulation is an excellent vehicle for examining these relationships, but a lack of programming ability can be a barrier that prevents call center managers from making

Robert Saltzman; Vijay Mehrotra

2004-01-01

407

A Performance Analysis of TMN Systems Using Models of Networks of Queues, Jackson's Theorem and Simulation  

Microsoft Academic Search

We analyze the performance of a telecommunications management network (TMN) system using models of networks of queues, Jackson's theorem, and simulation. TMN systems for managing public asynchronous transfer mode (ATM) networks generally have a four-level hierarchical structure consisting of a network management system, a few element management systems (EMSs), and several pairs of agents and ATM switches. We construct a

Young Ha Hwang; Sang Wook Chung; Gil-Haeng Lee; Young Il Kim

2002-01-01

408

Perturbation Analysis Gives Strongly Consistent Sensitivity Estimates for the M\\/G\\/1 Queue  

Microsoft Academic Search

The technique of perturbation analysis has recently been introduced as an efficient way to compute parameter sensitivities for discrete event systems. Thus far, the statistical properties of perturbation analysis have been validated mainly through experiments. This paper considers, for an M\\/G\\/1 queueing system, the sensitivity of mean system time of a customer to a parameter of the arrival or service

Rajan Suri; Michael A. Zazanis

1988-01-01

409

The Effect of Multiple Time Scales and Subexponentiality in MPEG Video Streams on Queueing Behavior  

Microsoft Academic Search

Guided by the empirical observation that real- time MPEG video streams exhibit both multiple time scale and subexponential characteristics, we construct a video model that captures both of these characteristics and is amenable to queueing analysis. We investigate two fundamental approaches for extract- ing the model parameters: using sample path and second-order statistics-based methods. The model exhibits the following two

Predrag R. Jelenkovic; Aurel A. Lazar; Nemo Semret

1997-01-01

410

Active Methodologies in a Queueing Systems Course for Telecommunication Engineering Studies  

ERIC Educational Resources Information Center

This paper presents the results of a one-year experiment in incorporating active methodologies in a Queueing Systems course as part of the Telecommunication Engineering degree at the University of Zaragoza, Spain, during the period of adaptation to the European Higher Education Area. A problem-based learning methodology has been introduced, and…

Garcia, J.; Hernandez, A.

2010-01-01

411

Active Methodologies in a Queueing Systems Course for Telecommunication Engineering Studies  

Microsoft Academic Search

This paper presents the results of a one-year experiment in incorporating active methodologies in a Queueing Systems course as part of the Telecommunication Engineering degree at the University of Zaragoza, Spain, during the period of adaptation to the European Higher Education Area. A problem-based learning methodology has been introduced, and the academic results showed that students achieved higher grades (improvement

José Garcia; Ángela Hernandez

2010-01-01

412

Trace-based evaluation of job runtime and queue wait time predictions in grids  

Microsoft Academic Search

Large-scale distributed computing systems such as grids are serving a growing number of scientists. These environments bring about not only the advantages of an economy of scale, but also the challenges of resource and workload heterogeneity. A consequence of these two forms of heterogeneity is that job runtimes and queue wait times are highly variable, which generally reduces system performance

Omer Ozan Sonmez; Nezih Yigitbasi; Alexandru Iosup; Dick H. J. Epema

2009-01-01

413

Transient and busy period analysis of theGI\\/G\\/1 queue: The method of stages  

Microsoft Academic Search

In this paper we study the transient behavior of the MGEL\\/MGEM\\/1 queueing system, where MGE is the class of mixed generalized Erlang distributions which can approximate an arbitrary distribution. We use the method of stages combined with the separation of variables and root finding techniques together with linear and tensor algebra. We find simple closed form expressions for the Laplace

Dimitris J. Bertsimas; Daisuke Nakazato

1992-01-01

414

2. VIEW OF SOUTHWEST APPROACH, SHOWING BUS STAGING AREA IN ...  

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

2. VIEW OF SOUTHWEST APPROACH, SHOWING BUS STAGING AREA IN FRONT OF THE PASSENGER STATION AND RELATIONSHIP OF PARKING LOT UNDER VIADUCT - Pennsylvania Railroad, Harrisburg Station & Trainshed, Market & South Fourth Streets, Harrisburg, Dauphin County, PA

415

Terrorist Attacks on Public Bus Transportation: A Preliminary Empirical Analysis.  

National Technical Information Service (NTIS)

This report provides data on terrorist attacks against public bus transportation targets and serious crimes committed against such targets throughout the world. The data are drawn from the MTI database of attacks on public surface transportation, which is...

B. M. Jenkins B. R. Butterworth K. S. Shrum

2010-01-01

416

Design of Wiring Structure by Considering Bus Bar Inductance  

NASA Astrophysics Data System (ADS)

Recently, high-switching-frequency and high-di/dt switching operation of inverters has been studied for the purpose of finding a way to reduce the size and weight of LC filters. In power electronic circuits, the stray inductance of the bus bar between a DC capacitor and power devices may cause an overshoot voltage and electromagnetic interference (EMI) noise for high-di/dt switching operation. Therefore, it is necessary to design the bus bar structure while considering the minimization and optimization of the bus bar inductance value. Generally, the bus bar inductance is analyzed by using 3D finite element method (FEM), but it takes a long time to construct analytical models and to perform the analysis. This paper proposes an improved calculation method for a medium-voltage inverter, based on the partial inductance calculation method. In addition, the wiring structure is designed by considering the stray inductance with using an inductance-mapping method.

Ando, Masato; Wada, Keiji

417

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

418

Public transit: Bus, paratransit, and ridesharing. Transportation research record  

SciTech Connect

Contents: part 1--bus operations--service reliability program of the southern california rapid transit district: a test of the short-term impacts on line 26-51; bus route o-d matrix generation: relationship between biproportional and recursive methods; transportation systems management options to improve urban bus route performance using computer simulation; development and application of performance measures for rural public transportation operators; rural public transportation in alaska: present and future options; particulate trap installation in a man articulated transit bus; part 2--paratransit--methodology for conducting a transportation survey of persons with disabilities; marketing rural transit among senior populations; evolution of functional eligibility and certification for paratransit service: the chicago experience; part 3--ridesharing--the state of the commute in southern california; hispanic market research in the southern california market; evaluation of second-year effectiveness of guaranteed ride home service at warner center transportation management organization; effectiveness of a statewide ridesharing promotion: california rideshare week.

Not Available

1992-01-01

419

AN INDIVIDUAL RECOGNITION AWARD PROGRAM FOR BUS OPERATORS  

Microsoft Academic Search

A successful Individual Recognition Award Program which was instituted at the Milwaukee County Transit System is described. The program, which was designed to encourage all bus operators to improve their attendance and to provide a \\

K J Warren; A Gulotta-Connelly

1987-01-01

420

Deregulation and Intercity Bus Operations in Florida: A Preliminary Study.  

National Technical Information Service (NTIS)

The impact of deregulation on the intercity bus industry and those who use the services of this industry is an issue of increasing interest given Florida's July 1, 1980, deregulation of motor carrier transportation of passengers and freight. This prelimin...

K. L. Borlaug E. H. Rastatter

1981-01-01

421

Methodology for Broadband Token Passing Bus Interoperability Testing.  

National Technical Information Service (NTIS)

The document describes a method for testing broadband token passing bus interoperability. The method was tested in a controlled laboratory environment at the National Bureau of Standards with four modem manufacturers' and three headend remodulator manufac...

R. Rosenthal D. P. Stokesberry

1987-01-01

422

Vertically Coupling of Resonant Cavities to Bus Waveguides.  

National Technical Information Service (NTIS)

Embodiments of the invention involve a monolithic vertical configuration for coupling a ring resonator and a bus waveguides. The monolithic vertical coupling arrangement, with the epitaxial grown coupling between the waveguide and the resonator, provides ...

C. K. Lin K. D. Djordjev M. R. T. Tan

2004-01-01

423

49 CFR 374.317 - Identification-bus and driver.  

Code of Federal Regulations, 2013 CFR

...Identification-bus and driver...374.317 Transportation Other Regulations...Relating to Transportation (Continued...DEPARTMENT OF TRANSPORTATION FEDERAL...REGULATIONS PASSENGER CARRIER REGULATIONS...Identificationâbus and...

2013-10-01

424

Bus Land with Intermittent Priority (BLIMP) Concept Simulation Analysis.  

National Technical Information Service (NTIS)

The Lane Transit District, in cooperation with the National Bus Rapid Transit Institute (NBRTI) at the University of South Florida, completed a preliminary implementation study to determine the potential impacts of a new and innovative transit priority tr...

G. Carey K. Giese T. Basuer

2009-01-01

425

These New Devices Aim to Enhance School Bus Safety.  

ERIC Educational Resources Information Center

Describes school bus safety products currently on the market, such as motion-sensing alarms, automatic breaking shields, front-mounted crossing gates, and strobe lights. Gives price information and evaluates products' usefulness and necessity. (MLH)

Stover, Del

1988-01-01

426

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

427

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

428

Empirical analysis of bus transit on-time performance  

Microsoft Academic Search

This paper presents an empirical assessment of factors affecting on-time performance in Portland, Oregon's fixed route bus system. A multinomial logit model relating early, late and on-time bus arrivals to route, schedule, driver and operating characteristics is developed and estimated. The model results show that the probability of on-time failures increases during PM peak periods, with longer headways and higher

James G. Strathman; Janet R. Hopper

1993-01-01

429

Sleep and Sleepiness among Brazilian Shift-Working Bus Drivers  

Microsoft Academic Search

The aim of this study was to evaluate daytime and nighttime sleep, as well as daytime and nighttime sleepiness of professional shift-working bus drivers. Thirty-two licensed bus drivers were assessed by nocturnal and diurnal polysomnography (PSG) recording and multiple sleep latency testing (MSLT) sessions. Sleep length was shorter and sleep efficiency reduced during daytime sleep compared with nighttime sleep. Thirty-eight

Eduardo H. R. Santos; Marco Tulio de Mello; Marcia Pradella-Hallinan; Ligia Luchesi; Maria Laura Nogueira Pires; Sergio Tufik

2004-01-01

430

Multipurpose bus interface utilizing a digital signal processor  

Microsoft Academic Search

A multi-purpose bus interface comprising a digital signal processor which receives a clock signal and control signals from a Manchester type encoder\\/decoder and then processes the clock and control signals allowing for the serial transfer of data to and from the 1553 multiplex data bus, the encoder\\/decoder and the digital signal processor into an IC memory card for storage in

Christian L. Houlberg

1994-01-01

431

Network-based in-vehicle body bus control system  

Microsoft Academic Search

It is a tremendous requirement that more things will be possible to connect to the Internet and there will be a great advantage that combines the Internet and in-vehicle bus control network. In this paper, we propose the design and implementation of a network-based in-vehicle body bus control system. We also consider an information specification using in the system, and

He Yu; Guihe Qin; Zhizhong Tian; Jinnan Dong

2010-01-01

432

Experiences of Fast Queue health care users in primary health care facilities in eThekwini district, South Africa.  

PubMed

Background: Comprehensive Primary Health Care (PHC), based on the principles of accessibility, availability, affordability, equity and acceptability, was introduced in South Africa to address inequalities in health service provision. Whilst the Fast Queue was instrumental in the promotion of access to health care, a major goal of the PHC approach, facilities were not prepared for the sudden influx of clients. Increased access resulted in long waiting times and queues contributing to dissatisfaction with the service which could lead to missed appointments and non-compliance with established treatment plans. Objectives: Firstly to describe the experiences of clients using the Fast Queue strategy to access routine healthcare services and secondly, to determine how the clients' experiences led to satisfaction or dissatisfaction with the Fast Queue service.Method: A descriptive qualitative survey using content analysis explored the experiences of the Fast Queue users in a PHC setting. Setting was first identified based on greatest number using the Fast Queue and geographic diversity and then a convenience sample of health care users of the Fast Queue were sampled individually along with one focus group of users who accessed the Queue monthly for medication refills. The same interview guide questions were used for both individual interviews and the one focus group discussion. Five clinics with the highest number of attendees during a three month period and a total of 83 health care users of the Fast Queue were interviewed. The average participant was female, 31 years old, single and unemployed.Results: Two themes with sub-themes emerged: health care user flow and communication, which highlights both satisfaction and dissatisfaction with the fast queue and queue marshals, could assist in directing users to the respective queues, reduce waiting time and keep users satisfied with the use of sign posts where there is a lack of human resources.Conclusion: Effective health communication strategies contribute to positive experiences by health care users and these can be effected by: (1) involvement of health care providers in planning the construction of health facilities to give input about patient flow, infection prevention and control and provision of privacy, (2) effective complaints mechanisms for users to ensure that complaints are followed up and (3)encouraging users to arrive at the facility throughout the day, rather than the present practice where all users arrive at the clinic early in the morning.  PMID:23902165

Sokhela, Dudu G; Makhanya, Nonhlanhla J; Sibiya, Nokuthula M; Nokes, Kathleen M

2013-01-01

433

Study of Headway Maintenance for Bus Routes: Causes and Effects of Bus Bunching in Extensive and Congested Service Areas.  

National Technical Information Service (NTIS)

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

G. Laferriere M. Figliozzi W. Feng W. C. Feng

2012-01-01

434

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

435

Efficient entanglement purification via quantum communication bus  

NASA Astrophysics Data System (ADS)

A scheme is proposed to implement entanglement purification for two remote less entangled photons using robust continuous variable coherent modes, called as quantum communication bus (qubus), rather than consuming expensive ancilla single-photon sources. The qubus beams in the coherent states provide for the natural communication in the purification protocol, instead of the classical communication between the distant photons. Weak cross-Kerr nonlinearities, qubus beams and quantum non-demolition (QND) photon-number-resolving measurement are utilized for implementing deterministic entanglement purification. The core element to realize the QND measurement is Kerr nonlinearity. The necessary QND measurement in the present scheme is not an extra, very difficult, addition to the present protocol, but is taken care of by a phase measurement. The entanglement purification protocol (EPP) can obtain a maximally entangled pair with only one step, instead of improving the fidelity of less entangled pairs by performing continuous indefinite iterative purification procedure. The total success probability and fidelity of the present purification scheme can approach unit in principle. In addition, we investigate photon loss of the qubus beams during the transmission and decoherence effects in the entanglement purification caused by such a photon loss.

Zhu, Meng-Zheng; Ye, Liu

2014-06-01

436

Discrete-time GeoX/G/1 queue with unreliable server and multiple adaptive delayed vacations  

NASA Astrophysics Data System (ADS)

In this paper we consider a discrete-time GeoX/G/1 queue with unreliable server and multiple adaptive delayed vacations policy in which the vacation time, service time, repair time and the delayed time all follow arbitrary discrete distribution. By using a concise decomposition method, the transient and steady-state distributions of the queue length are studied, and the stochastic decomposition property of steady-state queue length has been proved. Several common vacation policies are special cases of the vacation policy presented in this study. The relationship between the generating functions of steady-state queue length at departure epoch and arbitrary epoch is obtained. Finally, we give some numerical examples to illustrate the effect of the parameters on several performance characteristics.

Tang, Yinghui; Yun, Xi; Huang, Shujuan

2008-10-01

437

Dynamic Power Management of a System With a Two-Priority Request Queue Using Probabilistic-Model Checking  

Microsoft Academic Search

In this paper, we used the accepted methodology of applying probabilistic-model checking to dynamic power management. For the first time, we analyze in this context a dynamic-power-management system with the two request priorities. First system we consider has a single two-priority service request queue. Second system to be analyzed has two single service request queues that are dedicated for high-

Aleksandra Sesic; Stanisa Dautovic; Veljko Malbasa

2008-01-01

438

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

439

Bus dynamics for mobility-aid securement design.  

PubMed

Mobility-aid securement on large urban transit buses has been designed without an adequate knowledge of either the accelerations that are likely to occur in normal operations or the maximum accelerations that are possible short of an impact accident. These normal operation accelerations are important because they are the source of motion and corresponding sense of insecurity on the part of the passenger when riding in a mobility-aid on a bus. This paper describes the equipment and procedures used to measure the distribution of accelerations to be expected on large buses in normal transit service and the maximum accelerations possible during extreme maneuvering for six different sizes and types of transit buses. Included in the tests were low-floor buses of different lengths, a high-floor bus, a 40-ft (12.2-m) low-floor double-decker bus, and a 60-ft (18.3-m) low-floor articulated bus. During in-service tests, the accelerations were generally a function of the driver. In maneuvering tests, the mechanics of the bus design were the controlling factors. The results show that, in general, normal driving accelerations were typically less than 0.2 g in all directions and very rarely greater than 0.4 g. In the event of an emergency-driving situation, forward and turning accelerations may reach 0.4 g and stopping may result in 0.8 g. PMID:18335709

Zaworski, Joseph R; Hunter-Zaworski, K M; Baldwin, Matthew

2007-01-01

440

Overview hazard analysis for the H2Fuel Bus Program  

SciTech Connect

The H2Fuel Bus project is a joint development effort to produce a safe, near-zero emission, 32 passenger bus that is propelled by electric power with continuous on-board hydrogen powered battery recharging. A key initiative in the hydrogen bus development effort is a rigorous evaluation of operational safety. Westinghouse Savannah River Co., the prime contractor at the Department of Energy`s Savannah River Site, has developed a hazard analysis methodology designed to provide a systematic, comprehensive identification and evaluation of hazards. Although originally developed to support nuclear/chemical facility safety basis documentation, the SRS Methodology has widespread applicability to operations and/or systems that utilize hazardous materials and energy. This methodology was used to perform an overview hazard analysis for the H2Fuel Bus project to focus attention on those hypothetical circumstances that pose the greatest threat to the populace and property. The hazard analysis yields a listing of all known H2Fuel Bus hazards, postulated accident scenarios describing possible hazardous releases or conditions, an assessment of the scenarios in terms of frequency of occurrence and consequence, and binning in frequency-consequence space to assess the relative severity of postulated scenarios.

Hovis, G.L.

1996-06-18

441

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

442

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

443

Physics on the Bus-How About Physics on Your Bus?  

NASA Astrophysics Data System (ADS)

Riders on the buses of UMass Transit (here in the ``Five-College'' area) and of the University of Georgia transit system have something other than the usual ``Please don't eat on the bus'' placards to read-simple physics questions in the overhead advertising racks, with appealing cats and dogs posing questions, giving partial answers (some flat-out wrong, some partially correct), ending up with ``What do you think? ... Visit our website.'' One sample is given below; others can be viewed at http://www.amherst.edu/~physicsqanda. (More often than not, the dog gets it wrong; I'm a cat person.) This project was begun in collaboration with John King and was inspired by one of the many ideas described in his 2000 Oersted Medal address.

Romer, Robert H.

2004-12-01

444

Structural results for the control of queueing systems using event-based dynamic programming  

Microsoft Academic Search

In this paper we study monotonicity results for optimal policies of various queueing and resource sharing models. The standard\\u000a approach is to propagate, for each specific model, certain properties of the dynamic programming value function. We propose\\u000a a unified treatment of these models by concentrating on the events and the form of the value function instead of on the value

Ger Koole

1998-01-01

445

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

446

Sliding Mode Control with Fuzzy Reaching Law for Queue Management in the Internet  

Microsoft Academic Search

Due to the challenging nature of nonlinearity and time-varying behaviors in TCP dynamics, traditional active queue management (AQM) algorithms suffer from poor robustness under dynamic network scenarios. To address the above problem, a novel congestion control scheme named FSM-AQM is proposed via the fuzzy sliding mode control, which is robust against uncertainties and time-varying parameters of the system. The guidelines

Hao Wang; Zuohua Tian; Qinlong Zhang

2010-01-01

447

Active queue management controller design for TCP communication networks: Variable structure control approach  

Microsoft Academic Search

On the basis of variable structure control (VSC), an active queue management (AQM) controller is presented for a class of TCP communication networks. In the TCP\\/IP networks, the packet drop probability is limited between 0 and 1. Therefore, we modeled TCP\\/AQM as a rate-based non-linear system with a saturated input. The objective of the VSC-based AQM controller is to achieve

Chang-Kuo Chen; Teh-Lu Liao; Jun-Juh Yan

2009-01-01

448

Fuzzy and Real-Time Queue Management in Differentiated Services Networks  

Microsoft Academic Search

\\u000a In this paper, a robust active queue management system to secure high utilization as well as bounded delay and loss is designed.\\u000a Using this system, the network complies with the demands each traffic class set. We use Fuzzy Proportional-Integral-Derivative\\u000a (PID) controller in which the parameters of PID controllers are tuned based on fuzzy logic. The proposed controller is simple\\u000a to

Mahdi Jalili-kharaajoo; Mohammadreza Sadri; Farzad Habibipour Roudsari

2004-01-01

449

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

Microsoft Academic Search

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

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

2008-01-01

450

Design of Load-Adaptive Queue Management for Internet Congestion Control  

Microsoft Academic Search

\\u000a In this paper, we propose the Proportional-Integral-Derivative (PID)-controller, which can provide proactive congestion avoidance and control using an adaptive congestion indicator and control function.\\u000a The goals of PID-controller are to control congestion proactively, to stabilize the queue length around a desired level and\\u000a to give smooth and low packet loss rates. An extensive simulation study suggests that PID-controller outperforms other

Seungwan Ryu; Christopher Rump

2003-01-01

451

Fuzzy Logic Control for Active Queue Management in TCP\\/IP Networks  

Microsoft Academic Search

This paper presents a new active queue management (AQM) scheme, Fuzzy Explicit Marking (FEM), supporting explicit congestion notification (ECN), to provide congestion control in TCP\\/IP best-effort networks using a fuzzy logic control approach. While many AQM mechanisms have recently been proposed, these require careful configuration of non-intuitive control parameters, and show weaknesses to detect and control congestion under dynamic traffic

C. Chrysostomou; A. Pitsillides; G. Hadjipollas; M. Polycarpou; A. Sekercioglu

452

Design of robust active queue management controllers for a class of TCP communication networks  

Microsoft Academic Search

This paper describes the design of active queue management (AQM) controllers for a class of TCP communication networks. In TCP\\/IP networks, the packet-dropping probability function is considered as a control input. Therefore, a TCP AQM controller was modeled as a time-delayed system with a saturated input. The objective of the work described here was to design robust controllers capable of

Chang-kuo Chen; Yung-ching Hung; Teh-lu Liao; Jun-juh Yan

2007-01-01

453

Fuzzy-based PID active queue manager for TCP\\/IP networks  

Microsoft Academic Search

In this paper a novel Fuzzy-based proportional-integral derivative (PID) controller, which acts as an active queue manager (AQM) for Internet routers, is proposed. These controllers are used to reduce packet loss and improve network utilization in TCP\\/IP networks. The TCP\\/IP network is modeled as a time-delayed system with a saturated input. This is because of limitations of packet dropping probability

Shahram Mohammadi; H. M. Pour; M. Jafari; A. Javadi

2010-01-01

454

Dynamic matrix control for active queue management based on step response model  

Microsoft Academic Search

Most of existing active queue management (AQM) algorithms were designed on the fluid model of TCP\\/AQM dynamics which ignores the slow start and TCP timeout mechanism. Modeling TCP flows more precisely is very important to study AQM performance. To address this problem, this paper develops the step response model of TCP\\/AQM network based on the dumbbell topology in NS2. Then

Ping Wang; Hong Chen; Xiaohui Lu

2010-01-01

455

Tuning PI\\/PID active queue management controllers supporting TCP\\/IP flows  

Microsoft Academic Search

The active queue management (AQM) strategies are important in Internet congestion control, which bear the P\\/PI\\/PID controller structure essentially. But it is hard to configure the controlling parameters to achieve good tradeoff among a series of performance objectives. In this paper, we derive the approximate first order lag plus delay (FOLPD) model of TCP\\/AQM flows and present a guideline to

Yuedong Xu; Huifang Deng; Pingjian Zhang; Jie Yang

2005-01-01

456

A Predictive and Robust Active Queue Management for Internet Congestion Control  

Microsoft Academic Search

Recently many active queue management (AQM) algorithms have been proposed to address performance degradations of end-to-end congestion control. However, these AQM algorithms show weaknesses to detect and control congestion under dynamically changing network situations. In this paper, we propose a predictive and robust AQM algorithm, called proportional-integral-derivative (PID)-controller, using PID feedback control the incipient as well as current congestion adaptively

Seungwan Ryu; Christopher Rump; Chunming Qiao

2003-01-01

457

Design of active queue management algorithms for TCP networks: Nonlinear output feedback approach  

Microsoft Academic Search

This paper is concerned with the design of robust active queue management (AQM) controllers for a class of TCP networks. In TCP\\/IP networks, the packet-dropping probability function is limited between 0 and 1. Therefore, a TCP network with AQM controller was modeled as a rate-based non-linear system with a saturated input. The nonlinear output feedback AQM controller is proposed for

Meei-Ling Hung; Jun-Juh Yan; Cheng-Fang Huang; Teh-Lu Liao

2010-01-01

458

Active Queue Management of TCP\\/IP Networks Using Rule-Based Predictive Control  

Microsoft Academic Search

Model predictive controllers, due to their capability to control the time variant and delayed systems, are considered for congestion control in computer networks. To extend the application of these controllers as an active queue management (AQM) system in dynamic TCP\\/IP networks, a new rule-based predictive controller is proposed. This controller uses the small signal linearized fluid-flow model of the TCP\\/IP

Bahram Marami; Nooshin Bigdeli; Mohammad Haeri

2007-01-01

459

A Fuzzy-Expert-System-Based Structure for Active Queue Management  

Microsoft Academic Search

\\u000a In this paper, we demonstrate an example of using artificial intelligent in solving problems with complex and uncertain features\\u000a in communication networks. The concept of Fuzzy Expert System is used in the design of an Active Queue Management (AQM) algorithm.\\u000a Expert System and Fuzzy Logic are commonly used methods in solving various kinds of uncertain problems. Network congestion\\u000a control is

Jin Wu; Karim Djemame

2005-01-01

460

Adaptive Fuzzy Queue Management and Congestion Avoidance in TCP\\/AQM Networks  

Microsoft Academic Search

\\u000a Active Queue Management (AQM) takes a trade-off between link utilization and delay experienced by data packets. From control\\u000a point of view, it is rational to regard AQM as a typical regulation system. Recently many AQM algorithms have been proposed\\u000a to address performance degradations of end-to-end congestion control. However, these AQM algorithms show weaknesses to detect\\u000a and control congestion under dynamically

Mahdi Jalili-kharaajoo

2004-01-01

461

A Coupled Fuzzy Logic Control for Routers' Queue Management over TCP\\/AQM Networks  

Microsoft Academic Search

\\u000a Significant efforts in developing active queue management (AQM) in gateway routers in a TCP\\/IP network have been made since\\u000a random early detection (RED) in 1993, and most of them are statistical based. Our approach is to capitalize on the understanding\\u000a of the TCP dynamics to design an effective AQM scheme. In this paper, two FL-based AQM algorithms are proposed with

Zhi Li; Zhongwei Zhang

2005-01-01

462

LOCALIZED SWITCHING RAMP-METERING CONTROL WITH QUEUE LENGTH ESTIMATION AND REGULATION AND MICROSCOPIC SIMULATION RESULTS?  

Microsoft Academic Search

In this paper, we first review a localized ramp-metering strategy for freeways that achieves the goal of reducing the spatial and temporal span of traffic congestion, using locally available information. The control scheme is composed of a switching mainline-traffic responsive ramp-metering controller that adapts to the different traffic dynamics under different congestion conditions—free-flow or congested—and a queue length regulator that

Xiaotian Sun; Roberto Horowitz

463

Service Specific Queue Sorting and Scheduling Algorithm for OFDMA-Based LTE-Advanced Networks  

Microsoft Academic Search

In this paper two Service Specific Queue Sorting Algorithms (SSSA) are proposed for Real Time (RT) and Non Real Time (NRT) streaming video traffic, respectively. The proposed SSSA is implemented in a QoS aware dynamic Packet Scheduling Architecture (PSA) for Long Term Evolution-Advanced (LTE-A) networks and aims at improving the support of QoS guarantee and maintaining the overall system throughput

R. Kausar; Y. Chen; K. K. Chai

2011-01-01

464

Heavy-traffic limit theorems for the haevy-tailed GI\\/G\\/1 queue  

Microsoft Academic Search

The classic $GI\\/G\\/1$ queueing model of which the tail of the service time and\\/or the interarrival time distribution behaves as $t^{-v {S(t)$ for ${t rightarrow infty$, $1

J. W. Cohen

1997-01-01

465

TOWARDS BETTER MULTI-CLASS PARAMETRIC-DECOMPOSITION APPROXIMATIONS FOR OPEN QUEUEING NETWORKS  

Microsoft Academic Search

Methods are developed for approximately characterizing the departure process of eachcustomer class from a multi-class single-server queue with unlimited waiting space and the firstinfirst-out service discipline. The model is S(GI i \\/GI i )\\/1 with a non-Poisson renewal arrivalprocess and a non-exponential service-time distribution for each class. The methods provide abasis for improving parametric-decomposition approximations for analyzing non-Markov openqueueing networks

Ward Whitt

1992-01-01

466

Nurse-To-Patient Ratios in Hospital Staffing: A Queueing Perspective  

Microsoft Academic Search

The immediate motivation of this paper is California Bill AB 394, legislation which mandates fixed nurse-to-patient staffing ratios as a means to address the current crisis in the quality of health care delivery. Modeling medical units as closed queueing systems, we seek to determine whether or not ratio policies are effective at managing nurse workload. Our many-server asymptotic results suggest

Francis de Véricourt; Otis B. Jennings

2008-01-01

467

A Flexible Tomography Approach for Queueing Delay Distribution Inference in Communication Networks  

Microsoft Academic Search

We present in detail a flexible method for inferring in- ternal queueing-delay distributions in a network, by per- forming correlated unicast packet-pair measurements. The method is based on the quantization of the measured end- to-end delays, maximum-likelihood estimation via the ex- pectation maximization (EM) algorithm, and making nu- merical deconvolutions via the non-negative least squares (NNLS) algorithm. We have tested

P ´ Simon; Istvan Csabai

468

A solvable queueing network model for railway networks and its validation and applications for the Netherlands  

Microsoft Academic Search

Abstract The performance of new railway networks cannot be measured or simulated,as no detailed train schedules are available. Railway infrastructure and capacities are to be determined,long before the actual traffic is known. This paper therefore proposes,a solvable queueing,network,model,to compute,performance,measures,of interest without,requiring train schedules (timetables). Closed form expressions for mean delays are obtained. New network designs,traffic scenarios,and capacity expansions can so

Tijs Huisman; Richard J. Boucherie; Nico M. Van Dijk

2002-01-01

469

A Viscosity Solution Approach to the Asymptotic Analysis of Queueing Systems  

Microsoft Academic Search

We consider a system of several interconnected queues (with a single class of customers) and model the state $(X_t)$ of the system as a jump Markov process. The problem of interest is to estimate the large deviations behavior of the rescaled system $X^\\\\varepsilon_t = \\\\varepsilon X_{t\\/\\\\varepsilon}$, corresponding to large time and large excursions of the original (unscaled) system. The techniques

Paul Dupuis; Hitoshi Ishii; H. Mete Soner

1990-01-01

470

A combined activity\\/travel choice model for congested road networks with queues  

Microsoft Academic Search

This paper presents a combined activity\\/travel choice model and proposes a flow-swapping method for obtaining the model's dynamic user equilibrium solution on congested road network with queues. The activities of individuals are characterized by given temporal utility profiles. Three typical activities, which can be observed in morning peak period, namely at-home activity, non-work activity on the way from home to

William H. K. Lam; Hai-jun Huang

2002-01-01

471

Competing in a Queue for Resource Allocations among Non-Cooperative Agents  

Microsoft Academic Search

In this paper, we investigate a multi-agent non- cooperative game for resource allocations based on an M\\/D\\/1 queuing model. Specifically, agents with common goals to maximize utility are deployed to compete with each other to bid or bribe for quicker service provided by the server. The bid\\/bribe of each agent in the queue is not revealed, but the outcomes, in

Pinata Winoto; Tiffany Ya Tang

2002-01-01

472

Performance analysis of a cache-based multiprocessor system using closed queueing network model  

Microsoft Academic Search

An analysis for the performance measures (throughput and shared memory access time) of a cache-based multiprocessor system with multistage interconnection network is presented. The hit ratios of the shared data are obtained using Markov models based on various data movement policies. The developed closed queueing network model analyzes the performance of the multiprocessor system. Performance figures for 64×64 and 1024×1024

Venkat Tiruveedhula; J. S. Bedi

1991-01-01

473

LOGARITHMIC ASYMPTOTICS FOR STEADY-STATE TAIL PROBABILITIES IN A SINGLE-SERVER QUEUE  

Microsoft Academic Search

We consider the standard single-server queue with unlimited waiting space and the first-in first-out service discipline, but without any explicit independence conditions on the interarrival and service times. We find conditions for the steady-state waiting-time distribution to have small-tail asymptotics of the form x-1 logP(W?x) ? ?*as x ? ?for ?*?0. We require only stationarity of the basic sequence of

Peter W. Glynn; Ward Whitt

1993-01-01

474

Waiting-time tail probabilities in queues with long-tail service-time distributions  

Microsoft Academic Search

We consider the standard GI\\/G\\/1 queue with unlimited waiting room and the first-in first-outservice discipline. We investigate the steady-state waiting-time tail probabilities P(W > x) whenthe service-time distribution has a long-tail distribution, i.e., when the service-time distributionfails to have a finite moment generating function. We have developed algorithms for computingthe waiting-time distribution by Laplace transform inversion when the Laplace transforms

Joseph Abate; Gagan L. Choudhury; Ward Whitt

1994-01-01

475

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

476

A queueing theory description of fat-tailed price returns in imperfect financial markets  

NASA Astrophysics Data System (ADS)

In a financial market, for agents with long investment horizons or at times of severe market stress, it is often changes in the asset price that act as the trigger for transactions or shifts in investment position. This suggests the use of price thresholds to simulate agent behavior over much longer timescales than are currently used in models of order-books. We show that many phenomena, routinely ignored in efficient market theory, can be systematically introduced into an otherwise efficient market, resulting in models that robustly replicate the most important stylized facts. We then demonstrate a close link between such threshold models and queueing theory, with large price changes corresponding to the busy periods of a single-server queue. The distribution of the busy periods is known to have excess kurtosis and non-exponential decay under various assumptions on the queue parameters. Such an approach may prove useful in the development of mathematical models for rapid deleveraging and panics in financial markets, and the stress-testing of financial institutions.

Lamba, H.

2010-09-01

477

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

478

A queueing network model to analyze the impact of parallelization of care on patient cycle time.  

PubMed

The total time a patient spends in an outpatient facility, called the patient cycle time, is a major contributor to overall patient satisfaction. A frequently recommended strategy to reduce the total time is to perform some activities in parallel thereby shortening patient cycle time. To analyze patient cycle time this paper extends and improves upon existing multi-class open queueing network model (MOQN) so that the patient flow in an urgent care center can be modeled. Results of the model are analyzed using data from an urgent care center contemplating greater parallelization of patient care activities. The results indicate that parallelization can reduce the cycle time for those patient classes which require more than one diagnostic and/ or treatment intervention. However, for many patient classes there would be little if any improvement, indicating the importance of tools to analyze business process reengineering rules. The paper makes contributions by implementing an approximation for fork/join queues in the network and by improving the approximation for multiple server queues in both low traffic and high traffic conditions. We demonstrate the accuracy of the MOQN results through comparisons to simulation results. PMID:18826003

Jiang, Lixiang; Giachetti, Ronald E

2008-09-01

479

Demonstration of Caterpillar C-10 dual-fuel engines in MCI 102DL3 commuter buses  

SciTech Connect

The purpose of this program was to demonstrate the Caterpillar C-10 Dual-Fuel Natural Gas (DFNG) engine in an over-the-road bus application. Three new Motor Coach Industries (MCI) 102DL3 buses, equipped with Caterpillar C-10 DFNG engines, and one bus, equipped with a Caterpillar C-10 diesel engine, were operated side by side on similar fixed-route revenue service for a 12-month demonstration period (February 1998 to January 1999). The buses were used as part of the Clean Air Express Commuter Bus Program in Santa Barbara County, California. The performance and reliability of the DFNG engines were similar to that of the diesel engine, but the emissions results were mixed.

NONE

2000-02-28

480

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

481

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

482

Public transit 1993: Bus, paratransit, and ridesharing. Transportation research record  

SciTech Connect

Contents: evaluation of the operating cost consequences of signal preemption as an IVHS strategy; efficient transit priority at intersections; welfare comparison of fixed- and flexible-route bus systems; bus stop accessibility: a guide for virginia transit systems and public entities for complying with the americans with disabilities act of 1990; implications of technological developments for demand responsive transit; impact of nonresponse bias on forecasts of average passenger occupancy; what has happened to carpooling: trends in North Carolina, 1980 to 1990; ridesharing and the consumer: a tale of two marketing strategies; transportation demand management at small employer sites; and state of the commute in Southern California, 1992.

Kassabian, N.C.; Tobias, A.G.; Crayton, L.; Solomon, N.; Brown, S.E.G.

1993-01-01

483

Crash Protection Systems for Handicapped School Bus Occupants. Volume I. Executive Summary.  

National Technical Information Service (NTIS)

A series of sled tests were conducted to determine the influence of five major parameters on the occupant protection of handicapped school bus passengers. The selected parameters were bus crash pulse, dummy size, wheelchair orientation, wheelchair securem...

A. V. Khadilkan E. Will V. Costa

1981-01-01

484

Model to Evaluate the Impacts of Bus Priority on Signalized Intersections.  

National Technical Information Service (NTIS)

The concept of providing bus priority at signals is not new. Numerous cities have implemented bus priority strategies at signals with varying degree of success. Many of these cities have, however, discontinued using the priority measures. The advent of ne...

S. R. Sunkari P. S. Beasley T. Urbanik D. B. Fambro

1994-01-01

485

Deregulating Urban Bus Service: Britain's Early Experience and the Lessons for the United States.  

National Technical Information Service (NTIS)

The report evaluates the first eight months of British urban bus deregulation (from deregulation day, October 26, 1986, through the summer of 1987). The British program deregulated local bus services outside of the Greater London metropolitan area by (1) ...

J. A. Gomez-Ibanez, J. R. Meyer, P. Kerin, L. Meyer

1987-01-01

486

Advanced Technology Transit Bus: Final Test Report for the ATTB Prototypes.  

National Technical Information Service (NTIS)

This report provides results form the evaluation and testing program for the Advanced Technology Transit Bus (ATTB) program. The Advanced Technology Transit Bus development program with LACMTA was initiated in 1992 with the objective of developing a light...

H. L. Reuter

1999-01-01

487

77 FR 5295 - Over-the-Road Bus Accessibility Program Announcement of Project Selections  

Federal Register 2010, 2011, 2012, 2013

...TRANSPORTATION Federal Transit Administration Over-the-Road Bus Accessibility Program...Selections AGENCY: Federal Transit Administration (FTA...Transportation (DOT) Federal Transit Administration (FTA...the Over-the-Road Bus (OTRB)...

2012-02-02

488

77 FR 71865 - Over-the-Road Bus Accessibility Grant Program  

Federal Register 2010, 2011, 2012, 2013

...TRANSPORTATION Federal Transit Administration Over-the-Road Bus Accessibility Grant Program AGENCY: Federal Transit Administration (FTA...Transportation (DOT) Federal Transit Administration (FTA...the Over-the-Road Bus (OTRB)...

2012-12-04

489

76 FR 17738 - Over-the-Road Bus Accessibility Program Announcement of Project Selections  

Federal Register 2010, 2011, 2012, 2013

...TRANSPORTATION Federal Transit Administration Over-the-Road Bus Accessibility Program...Selections AGENCY: Federal Transit Administration (FTA...Transportation's (DOT) Federal Transit Administration (FTA...the Over-the- Road Bus (OTRB)...

2011-03-30

490

75 FR 20034 - Over-the-Road Bus Accessibility Program Grants: Corrections  

Federal Register 2010, 2011, 2012, 2013

...TRANSPORTATION Federal Transit Administration Over-the-Road Bus Accessibility Program...Corrections AGENCY: Federal Transit Administration (FTA...January 15, 2010 Federal Transit Administration (FTA...Over-the-Road Bus Accessibility...

2010-04-16

491

Performance evaluation of UHF RFID technologies for real-time bus recognition in the Taipei Bus Station.  

PubMed

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

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

2013-01-01

492

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

PubMed Central

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

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

2013-01-01

493

Numerical Research on LNG Tank Leakage Effect on Environment for LNG Bus  

Microsoft Academic Search

Study and analysis the fuel leakage security of current LNG alternative fuel bus. Do the simulation on surrounding concentration and temperature of LNG bus fuel tank leakage by Computational Fluid Dynamics (CFD). By analyzing the influence of three different bus velocities, 0km\\/h, 30km\\/h and 80km\\/h, we have the conclusion from the simulation that when the bus gets faster, the influence

Lei Zhang; Ying Gao; Da-wen Liu; Peng Liu

2011-01-01

494

A macroscopic model for integrating bus signal priority with vehicle rescheduling  

Microsoft Academic Search

When a bus breaks down on a scheduled trip, one or more vehicles need to be rescheduled to serve that trip and other scheduled\\u000a trips. A bus breakdown certainly delays the trip being served by the disabled bus and possibly delays or cancels other trips.\\u000a The vehicle rescheduling problem (VRSP) is to reassign and reschedule the bus fleet to minimize the

Pitu B. Mirchandani; Jing-Quan Li; Mark Hickman

2010-01-01

495

Design and implementation of dc-bus system module for parallel integrated sustainable energy conversion systems  

Microsoft Academic Search

In this paper, a performance analysis of a highly integrated, high-performance dc-bus system module is presented. This module introduces a solution for medium & low voltage DC distribution applications. It is designed for applications requiring a single bus solution to control up to twelve DC-sources sharing same dc-bus and having same dc-voltage level. The bus is also designed to interface

Mahmoud M. Amin; O. A. Mohammed

2011-01-01

496

A scheduling model and a solution algorithm for inter-city bus carriers  

Microsoft Academic Search

The setting of timetables and bus routing\\/scheduling are essential to an inter-city bus carrier's profitability, its level of service and its competitive capability in the market. In the past, carriers in Taiwan usually set their timetables and bus routes\\/schedules manually, which was inefficient. In this research we thus attempt to develop a model that will help Taiwan inter-city bus carriers

Shangyao Yan; Hao-Lei Chen

2002-01-01

497

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

Code of Federal Regulations, 2010 CFR

...during the bus' normal life cycle. Much of the maintainability...during the bus durability test at the proving ground...twenty-five percent of the bus life will be simulated and...vehicle's normal service life. During the test there will be...

2009-10-01

498

Research on designing method of CAN bus and Modbus protocol conversion interface  

Microsoft Academic Search

Fieldbus has become one of the most active fields in industrial data bus area. However, fieldbus standards are not uniform at present, which brings many difficulties to different industrial control equipments from different manufacturers to connect their devices to others. CAN bus and Modbus bus are two kinds of more popular buses in industrial control systems. This paper analyses these

Lou Guohuan; Zhang Hao; Zhao Wei

2009-01-01

499

76 FR 13580 - Bus Testing; Calculation of Average Passenger Weight and Test Vehicle Weight  

Federal Register 2010, 2011, 2012, 2013

...SUMMARY: The Federal Transit Administration (FTA) is proposing to amend its bus testing regulation to more...mandate of verifying that the bus can withstand the rigors of regular transit service, and testing a bus up to its GVWR but no...

2011-03-14

500

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