CVRIA Glossary

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Parse

To extract individual elements from a larger message.

Performance Measure

Indicator of how well the transportation system is performing with regard to such measures as average speed, reliability of travel, and accident rates. Used as feedback in the decisionmaking process.

Permission

Authorization granted to do something. From the System's perspective, permissions are granted to System Users and Operators determining what actions they are allowed to take when interacting with the System.

Persistent connection

A connection between two networked devices that remains open after the initial request is completed, to handle multiple requests thereafter. This reduces resource overhead of re-establishing connections for each message sent and received. This is opposite of Session-oriented Connection.

Physical Object

Person, place, or thing that makes up the connected vehicle environment. They are defined in terms of the applications they support, the processing they include, and their interfaces with other physical objects. They are grouped into four classes: Centers, Field, Vehicles, and Travelers. Example physical objects are the Traffic Management Center, the Vehicle Onboard Equipment, and the ITS Roadway Equipment. These correspond to the physical world: respectively traffic operations centers, equipped connected automobiles, and roadside signal controllers. Due to this close correspondence between the physical world and the physical objects, the interfaces between them are prime candidates for standardization.
In CVRIA, Physical Objects are defined with scope such that they are under the control of a single Enterprise Object.

Physical Security

Safeguards to deny access to unauthorized personnel (including attackers or even accidental intruders) from physically accessing a building, facility, resource, or stored information. This can range from simply a locked door to badge entry. with armed security guards

Physical View

The part of the Connected Vehicle Reference Implementation Architecture (CVRIA) that provides deployers and agencies with a physical representation (though not a detailed design) of the important connected vehicle interfaces and major system components. It describes the connections between Physical Objects within the connected vehicle environment. The physical view is depicted as a set of integrated Physical Objects that interact and exchange information to support the connected vehicle applications. It provides a high-level structure around the processes and data flows defined in the Functional View. The principal elements in the physical view are the physical objects and information flows that connect these physical objects into an overall structure. These architecture flows and their communication requirements define the interfaces required between physical objects, which form the basis for much of the ongoing standards work in the ITS program.

PNG

Portable Network Graphics file. A graphics file format that has many advantages, including their compatibility across browsers and office applications. Images in PNG format can be resized without distortion and loss of detail. Available for download for selected diagrams (e.g., application diagrams). Many diagrams displayed on the CVRIA web site are actually in GIF format.

Policy

A set of guidelines and constraints on the behaviors and states exhibited by the objects in the CVRIA.

Port

The physical element of a Node where a Link is connected. Nodes may have one or more Ports.

Priority

A rank order of status, activities, or tasks. Priority is particularly important when resources are limited.

Privacy

The ability of an individual to seclude information about themselves, and thereby reveal information about themselves selectively. From the VII Privacy Policies Framework: the respect for individual choices about, and control over an individual's personal information.

Problem domain

A set of similar problems that occur in an environment and lend themselves to common solutions.

Process

A series of actions, changes, or functions bringing about a result. A function or activity identified in the functional view of the Connected Vehicle Reference Implementation Architecture (CVRIA) that is required to support the requirements for the connected vehicle applications. The functional view presents processes in a top-down fashion beginning with general processes (e.g., "Manage Traffic") that are then decomposed into more detailed processes (e.g., "Provide Traffic Surveillance", "Monitor HOV Lane Use"). The most detailed processes (sometimes called primitives) are defined in Process Specifications (PSpecs).

Process Specification (pspec)

The textual definition of the most detailed processes identified in the functional view of the Connected Vehicle Reference Implementation Architecture (CVRIA). The process specification includes an overview, a set of functional requirements, and a complete set of inputs and outputs.

Project Architecture

A framework that identifies the institutional agreement and technical integration necessary to implement a connected vehicle project, including integration with other ITS projects and systems.

Protocol

Protocol Data Unit (PDU)

A defined data structure that is transferred at a peer level between corresponding software entities functioning at the same layer in the Open System Interconnect (OSI) standard model which are operating on different computing platforms that are interconnected via communications media.

Protocol Entity or Object

An object that performs actions to exchange or transfer data (as distinguished from a Functional Object that generates or processes data). Protocol Objects or Entities are used to support interactions between two Engineering Objects or among groups of Engineering Objects that are contained in separate Nodes (see the Physical Viewpoint for discussion of Engineering Objects and Nodes).

Pseudo-ID

An identifier used by an individual that is not associated with the individual's identity, and may change to prevent such association.

Public Key

In cryptography, a public key is a value provided by some designated authority as an encryption key that, combined with a private key derived from the public key, can be used to effectively encrypt messages and digitally sign them. The use of combined public and private keys is known as asymmetric cryptography. A system for using public keys is called a public key infrastructure (PKI).