No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
A Structured Approach to Developing Real-Time, Distributed Network Applications for ITS Deployment
... The SDD data communications model described here does not propose to perform any actions on the data flow. In our model, the data flows through a series of components [21] and is transformed by the components so that the communication task and protocol are independent of the data flow. It is possible to create a component that would perform a request/response interaction with clients but that is outside the scope of defining an SDD flow. ...
... The dictionary contents is the information about the actual sensors in this data transfer that can be used to construct a database describing either: 1) the slowly changing dynamic contents or 2) the unchanging static contents. This is the component that contains particular values describing attributes of each sensor (e.g., sensor one is at 122. 23 longitude, 47. 21 latitude, and measures rainfall in inches). We define a contents language and associated parser to facilitate verification that the schema contents are compatible with the schema into which they are to be placed. ...
... Transfer of the dictionary and data between computer systems is accomplished by encoding the data according to the basic encoding rules (BERs) defined for the ASN.1 standard. As a block of data is received, it is encoded and sent to all clients using the redistributor methodology detailed in [21]. In our example application, the data is a stream of bytes, and the information is extracted using algorithms specified in the data dictionary. ...
The wide variety of remote sensors used in Intelligent Transportation Systems (ITS) applications (loops, probe vehicles, radar, cameras, etc.) has created a need for general methods by which data can be shared among agencies and users who own disparate computer systems. In this paper, we present a methodology that demonstrates that it is possible to create, encode, and decode a self-describing data stream using: 1) existing data description language standards; 2) parsers to enforce language compliance; 3) a simple content language that flows out of the data description language; and 4) architecture neutral encoders and decoders based on ASN.1.
... The SDD transfer can be implemented either by viewing the MIB as a control that initiates an out of band data transfer, as in [15], or the MIB can actually contain the components of SDD as objects. SDD transfers leverage NTCIP in that SDD has an agreed-upon data-description language that includes methods to describe and extract the elements of data from a data stream without the need for a great deal of a priori knowledge. ...
... Transfer of the dictionary and data between computer systems is accomplished by encoding the data according to the Basic Encoding Rules (BER) defined for the ASN.1 standard. As a block of data is received, it is encoded and sent to all clients via the redistributor methodology detailed in [15]. In our application, the data are a stream of bytes, and the information is extracted with algorithms specified in the Data Dictionary. ...
The wide variety of remote sensors used in intelligent transportation systems (ITS) applications (loops, probe vehicles, radar, cameras, etc.) has created a need for general methods by which data can be shared among agencies and users who own disparate computer systems. In this paper a methodology is presented that demonstrates that it is possible to create, encode, and decode a self-describing data (SDD) stream using existing data description language standards, parsers to enforce language compliance, a simple content language that flows out of the data description language, and architecture neutral encoders and decoders based on Abstract Syntax Notation One (ASN.1). Further, it documents a reference implementation of an SDD receiver.
... Dailey et al. introduced a distributed intelligent transportation system [3] to apply to domains where real-time data is asynchronously provided by spatially distributed, heterogeneous sensor systems like road networks. ...
... First Level assume that each governed sub-graph G c0 is path-connected, i.e., for all nodes n 1 , n 2 ∈ G c0 there exists an internal path in G c0 from n 1 to n 2 (without leaving G c0 ). 3 This property will prove useful for the reasoning process later introduced in Section 5. ...
This paper introduces a generic approach to integrating dif-ferent kinds of geo-referenced sensor measurements along a physical in-frastructure. The underlying core ontology is domain-independent and realized using Semantic Web technologies; it can be specialized for dif-ferent domains. In particular, railway infrastructures are presented as a case study. Using the physical infrastructure as a common spatial refer-ence system constitutes a central point of the integration, which allows to perform reasoning tasks, such as answering network-related queries (involving measurements from both stationary and mobile sensors). A classification of different query types is presented together with the cor-responding algorithms.
... Loupe has been used for the verification of P/S architectures ranging from control of road tunnels [5] to remote assistance to elderly people [3]. Here we illustrate the use of Loupe in the design of an information system for transport scenarios [23]. ...
... Consider the problem of monitoring a fleet of buses in a metropolitan area. The scenario is a realistic one, as demonstrated by large efforts currently under way [23], [58]. A system to achieve this goal is composed of the following actors: ...
The Publish-Subscribe (P/S) communication paradigm fosters high decoupling among distributed components. This facilitates the design of dynamic applications, but also impacts negatively on their verification, making it difficult to reason on the overall federation of components. In addition, existing P/S infrastructures offer radically different features to the applications, e.g., in terms of message reliability. This further complicates the verification as its outcome depends on the specific guarantees provided by the underlying P/S system. Although model checking has been proposed as a tool for the verification of P/S architectures, existing solutions overlook many characteristics of the underlying communication infrastructure to avoid state explosion problems. To overcome these limitations, the Loupe domain-specific model checker adopts a different approach. The P/S infrastructure is not modeled on top of a general-purpose model checker. Instead, it is embedded within the checking engine, and the traditional P/S operations become part of the modeling language. In this paper, we describe Loupe's design and the dedicated state abstractions that enable accurate verification without incurring state explosion problems. We also illustrate our use of state-of-the-art software verification tools to assess some key functionality in Loupe's current implementation. A complete case study shows how Loupe eases the verification of P/S architectures. Finally, we quantitatively compare Loupe's performance against alternative approaches. The results indicate that Loupe is effective and efficient in enabling accurate verification of P/S architectures.
... Einen verteilten Ansatz für allgemeine Verkehrstelematik-Systemen stellen Dailey et al. vor [DHM96]. Hier werden vier Typen von Systemkomponenten unterschieden, die entweder Sensordaten produzieren, verteilen, verarbeiten oder konsumieren. ...
... Real time data stream will provides an interactive query or update of information and enables data analysis to be executed on-the-fly. From the integrated spatial database this system will also enables detailed analysis of pipeline data from present or historical inspections and provide spatial information for graphical output, for reports and further analysis (9), (10) . This paper discusses the design challenges; proposed the architecture framework, describes the system components and presents the benefits of developing RTPPTMS in sequential order. ...
Many tracking method have been used to detect the movement of pigs through pipelines over the years. With varying degrees of success these systems can be made to do the job for which they were created. Alas, in terms of data collection and inputs, the tracking of pigs involved loads of manual data collection. Manual data input necessitate the training of on-site workers as to how to interpret data, allow time for its input, and include error assumptions in final reports and obviously all this at the expense of the pipeline operator. Considering the large amount of data and the critical timescales of pigging operations, it is ideal that data input take place electronically. This paper discusses the possibility to develop Real Time Pig Tracking and Monitoring System by presenting the architecture framework which addresses different components from acquisition layer to presentation layer and, the challenges and trade-off to develop this system.
... We develop a Real Time Tracking and Monitoring System for Pipeline Pigging (RTTMPP) to overcome some of mentioned problems. It provides similar functionality to the Intelligent Transport System (ITS) [3] [4]. It shows different pigs location in different sections or pipelines and at the same time allows an interactive input, query or update of information. ...
In order to track a pig inside a pipeline and sending the data in real time, it is highly important to have a magnetic module that is strong enough to saturate a section of the pipeline. The issue is to specify the exact location of where the module should be placed to achieve the best tracking results to transmit the data. This paper describes the setting up of the experiments and their finding that has been carried out to examine the relationship of the distance between the magnetic module and the pig with respect to the magnetic field strength detected at gradiometer. Detail analysis of the result shows that the strength of the magnetic force field would lessen by half if the module sticks to the pig.
... Außerdem gibt es Untersuchungen zum Einsatz satellitengestützer Verkehrsdatenerfassungssysteme mittels GPS [www-Multisat]. In dem Projekt Floating Car Data (FCD) wird auf Verkehrszustände im Umfeld von Einzelfahrzeugen aus deren GPS-Aufzeichnungen geschlossen [Schäfer, 2003] [Dailey, 1996]. ...
Aufgrund der steigenden Verkehrsnachfrage und der begrenzten Resourcen zum Ausbau der Straßenverkehrsnetze werden zukünftig größere Anforderungen an die Effektivität von Telematikanwendungen gestellt. Die Erhebung und Bereitstellung aktueller Verkehrsdaten durch geeignete Sensoren ist dazu eine entscheidende Voraussetzung. Gegenstand dieser Arbeit ist die großflächige Analyse des Straßenverkehrs auf der Basis bodengebundener und verteilter opto-elektronischer Sensoren. Es wird ein Konzept vorgestellt, dass eine von der Bilddatenerhebung bis zur Bereitstellung der Daten für Verkehrsanwendungen durchgehende Verarbeitungskette enthält. Der interdisziplinäre Ansatz bildet die Basis zur Verknüpfung eines solchen Sensorsystems mit Verkehrstelematik. Die Abbildung des Verkehrsgeschehens erfolgt im Gegensatz zu herkömmlichen bodengebundenen Messsystemen innerhalb größerer zusammenhängender Ausschnitte des Verkehrsraums. Dadurch können streckenbezogene Verkehrskenngrößen direkt bestimmt werden. Die Georeferenzierung der Verkehrsobjekte ist die Grundlage für eine optimale Verkehrsanalyse und Verkehrssteuerung. Die generierten Daten sind Basis zur Findung und Verifizierung von Theorien und Modellen sowie zur Entwicklung verkehrsadaptiver Steuerungsverfahren auf mikroskopischer Ebene. Es wird gezeigt, wie aus der Fusion gleichzeitig erhaltener Daten mehrerer Sensoren, die im Bereich des Sichtbaren und im thermalen Infrarot sensitiv sind, ein zusammengesetztes Abbildungsmosaik eines vergrößerten Verkehrsraums erzeugt werden kann. In diesem Abbildungsmosaik werden Verkehrsdatenmodelle unterschiedlicher räumlicher Kategorien abgeleitet. Die Darstellung des Abbildungsmosaiks mit seinen Daten erfolgt auf unterschiedlichen Informationsebenen in geokodierten Karten. Die Bewertung mikroskopischer Verkehrsprozesse wird durch die besondere Berücksichtigung der Zeitkomponente bei der Visualisierung möglich. Die vorgestellte Verarbeitungskette beinhaltet neue Anwendungsbereiche für geografische Informationssysteme (GIS). Der beschriebene Ansatz wurde konzeptionell bearbeitet, in der Programmiersprache IDL realisiert und erfolgreich getestet.
... II. Component Architecture and AVL Data The applications architecture presented here is created using the component architecture described in [4] where the interprocess communication is done using self describing data (SDD), as described in [5]. Figure 1 is a represen tation of the applications where the individual components are shown in the boxes and the lines connecting the boxes are interprocess communications channels that use SDD over TCP/IP. This kind of modular application is desirable for a variety of reasons: (1) The application started with one transit agency and easily expanded to four. ...
In past work we described a system of components that are used to construct transit traveler information applications. In this paper we describe an ongoing project that uses the same component architecture to combine maps, schedules, and AVL information from four transit agencies. The result is a set of Web applications suitable for both transit management and traveler information. We describe both the technical and administrative challenges to be overcome in building a regional (10000 square miles) transit AVL and information system.
... An Automated Vehicle Location (AVL) system tracks each bus using a combination of odometry and signpost transmitters [7]. Internet users can monitor the location of each bus in real-time using the Busview software [6][7][8]. We developed mechanisms for recording the data being delivered to Busview clients, and for converting the recorded data into movement patterns suitable for use in the ns-2 network simulator [9], which we use to evaluate our system (Section 7). Figure 4(a) shows the number of buses in the traces we collected over a two week period starting on Saturday, November 17, 2001. ...
Few real-world applications of mobile ad hoc networks have been developed or deployed outside the military environment, and no traces of actual node movement in a real ad hoc network have been available. We propose a novel commercial application of ad hoc networking, we describe and evaluate a multitier ad hoc network architecture and routing protocol for this system, and we document a new source of real mobility traces to support detailed simulation of ad hoc network applications on a large scale. The proposed system, which we call Ad Hoc City, is a multitier wireless ad hoc network routing architecture for general-purpose wide-area communication. The backbone network in this architecture is itself also a mobile multihop network, composed of wireless devices mounted on mobile fleets such as city buses or delivery vehicles. We evaluate our proposed design through simulation based on traces of the actual movement of the fleet of city buses in the Seattle, Washington metropolitan area, on their normal routes providing passenger bus service throughout the city.
... The Busview applet is built using the component architecture described in (1). This architecture has been instantiated as the ITS Backbone of the Smart Trek MDI project. ...
The Seattle model deployment initiative has created a new technology for data sharing in an ITS environment. This technology, the ITS Backbone that uses Self Describing Data (http:/ /www.its.washington.edu/bbone/), creates a framework in which to build applications. These applications use Self Describing Data (SDD) to obtain real-time data over the Internet to perform functions ranging from ATMS to ATIS. Since the applications depend only on knowledge of SDD, they are portable to any jurisdiction where SDD is employed as the data transfer support. (SDD information and software are available for download from the ITS Backbone page noted above.) This paper describes the implementation of two such portable applications. INTRODUCTION As part of the Seattle Smart Trek model deployment, two new applications where created to provide real-time transit information. The two venues where transit riders need information are (1) on the desktop and (2) at the transit center. The first project, Busv...
Automated traffic data being posted on the Internet by an increasing number of cities are a potentially invaluable source of information on national vehicle travel and highway system performance. An experimental system is presented that demonstrates the feasibility of using these data to create national indicators of vehicle travel and traffic congestion. The experiment raises a number of critical institutional and technical issues that must be resolved before a complete national system can be realized. This paper represents a progress report on the initial phase of an ongoing study.
An algorithm is presented to predict transit vehicle arrival times up to 1 h in advance. It uses the time series of data from an automated vehicle location system, consisting of time and location pairs. These data are used with historical statistics in an optimal filtering framework to predict future arrivals. The algorithm is implemented for a large transit fleet in Seattle, Washington, and the prediction results for hundreds of locations are made widely available on the Web. An evaluation of the second busiest but most complex prediction site is presented to demonstrate the value of prediction over the use of schedules alone.
This case study involved the review of the advanced traveler information system (ATIS) and advanced traffic management system (ATMS) and the use of the information backbone (I2B) component of the intelligent transportation system of the Seattle Metropolitan Model Deployment Initiative. Through a survey of documents and other material combined with interviews of key participants, the nature of any increased benefits or reduced costs associated with ATIS and ATMS integration resulting from the I2B was examined. The results suggest that the distributed nature of the I2B provided for the coordination of responsibility among multiple information contributors and processors as well as geographic flexibility. The open nature of participation was also cited as a factor in making connection to the I2B a relatively easy matter since software tools for interfacing are provided. For contributors, the I2B has provided the ability to distribute information via a single access method, thereby reducing support effort. Processors can gain easier access to existing information in addition to being able to develop composite information from multiple sources. Comparison of costs between the I2B and alternative information system designs was difficult because of the differences in functionality provided. However, it appears likely that costs are shifted from the information contributors to the processors, who gain from the addition and realization of value in the marketplace.
This paper presents an algorithm to predict transit vehicle
arrival times up to an hour in advance. The time series of data from an
automated vehicle location system, consisting of time and location
pairs, is used with historical statistics in an optimal filtering
framework to predict future arrivals
The wide variety of remote sensors used in intelligent transportation systems (ITS) applications (loops, probe vehicles, radar, cameras etc.) has created a need for general methods by which data can be shared among agencies and users who own disparate computer systems. We present a methodology that demonstrates that it is possible to create, encode, and decode a self-describing data stream using: (1) existing data description language standards, (2) parsers to enforce language compliance, (3) a simple content language that flows out of the data description language, and (4) architecture neutral encoders and decoders based on ASN.1
The Smart Trek Model Deployment Initiative, a US Department of Transportation-funded intelligent transportation systems program in the Puget Sound region, has made great strides in integrating and disseminating traveler information. The initiative focuses on real time information to help travelers make informed decisions about their travel options. The Smart Trek project has brought about a variety of real time transit information applications. One of these is MyBus, which makes departure predictions and delivers traveler information to Web browsers and cell phones. MyBus aims to present to riders, in real time, the predicted departure times of buses at specific locations throughout a transit region. King County Metro, Seattle's transit agency, operates a large fleet. Up to 1200 vehicles are in service simultaneously, departing from over 1000 locations. MyBus predicts approximately 210000 weekday and 140000 weekend scheduled departure events. This is over a million departure predictions per week. MyBus has shown that predictions on this scale are feasible and manageable. Several technologies are central to the success of MyBus. A common format for the transit agency schedule and spatial data was crucial, letting us redeploy the Seattle pilot project with data from the Portland Tri-Met transit agency with minimal effort. The format we chose was a database schema based directly on the Transit Communications Interface Profiles standards.
Great advances have been achieved in distributed systems during the last decade. In particular, a rapid technological deployment has taken place in communication networks and protocols. On top of basic communication protocols, several higher-level communication facilities have been developed to support distributed applications. From the application point of view, there is a growing demand for distributed programming. Important example areas are computer-integrated manufacturing and office automation.The paper surveys the distributed application support area, especially focusing on distributed programming and configuration techniques, use of object-oriented techniques, and development support. Several existing approaches are classified and compared with each other. Important communication approaches covered are extended message passing and remote procedure call facilities, as well as new distributed object-oriented interaction mechanisms and multiparty communication support. Important distributed configuration management issues include placement and structure support for distributed applications, dynamic configuration change support, and associated configuration languages. Details are derived from foreign system developments as well as from personal experiences with distributed systems. As an integration effort, the architecture of an object-oriented environment for distributed application development support is outlined.The paper is for researchers interested in further work in the area of distributed systems and software developers interested in a survey of existing mechanisms to support their development work.