Module 33 - A317a
A317a: Understanding User Needs for CCTV Systems Based on NTCIP 1205 Standard
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A317a: Understanding User Needs for CCTV Systems Based on NTCIP 1205 Standard
Table of Contents
The purpose of this module is to teach the students how to identify and write user needs specific to the NTCIP 1205 v01 CCTV Standard, which does not currently contain user needs and requirements. The focus of this module is to assist technical staff in developing a set of user needs that meet operational needs to support traffic management and traveler information service functions.
This module explains the scope of the CCTV Standard and details available to users. It provides information helpful in identifying the uses and associated operational needs of CCTV systems. This module is to be placed in the context of the SEP as well as in the acquisition curriculum path with I101, A101, A102, A201, and A202 modules being the prerequisites.
This module builds on A202: Identifying and Writing User Needs When ITS Standards Do Not Have SEP Content, which defined user need extraction process and techniques linked to the NTCIP 1205 v01 Standard and acquire a CCTV system based on what the user is seeking to accomplish with support from tools and resources such as an MIB and conformance groups and statement.
1. Introduction to CCTV System and User Needs
Close Circuit Television (CCTV) System or CCTV System
A System is a collection of components organized to accomplish a specific function or set of functions. In the ITS standards deployments, we deal with systems or subsystems which consist of multiple field devices. CCTV system is one of the most widely used ITS subsystem.
The term CCTV has a specific meaning; a CCTV images remains within the circuit, unlike the broadcast TV images which can be seen by anyone. The CCTV system consists of multiple
cameras installed on a transportation facility to provide "images" in near real-time and includes monitors and camera control unit. Additional parts are added as need to share video and record images for later uses. The CCTV systems in many variations are used in a major way in both security industry to protect property and people, and in transportation-ITS deployments for managing networks and services in real-time. Thus a CCTV system can be termed as a safety and security tool.
Here is how Virginia Department of Transportation (VDOT) defines its CCTV system:
The "CCTV system", for the purposes of (VDOT document), is defined as the use of VDOT owned and operated video cameras located along VDOT and associated County assets in the NRO region for traffic surveillance, congestion monitoring, incident verification, and public/media information. The CCTV system includes the CCTV cameras, communication infrastructure, and the variety of output sources (Ref.8).
The CCTV system provides versatile real-time visual information to the xxTMC operators. Acting as eyes in the field, the system aids TMC operators in quickly and effectively identifying and responding to incidents, events, and maintenance needs. A CCTV camera is typically equipped with pan-tilt-zoom capabilities to allow the operator to adjust the view and observe specific areas. The information obtained from the video provides confirmation of traffic incidents, event, weather conditions, and emergency issues. The CCTV camera system also provides video distribution for public and media use (Ref.8).
Specific Uses of a CCTV System in Transportation Sector
Understanding Permissible Use of Video Feeds Made available by the TMC Examples (Based on Arizona Department of Transportation)
How does NTCIP use a CCTV System?
The NTCIP communications layout shown in Figure 1 shows how a central management station to communicate to the field cameras in real-time and control device for multiple uses.
(Extended Text Description: CCTV System Communications Interface: There are two text boxes in the figure-Management Station Applications and SNMP Agent. At the top right, both are connected with one-way arrow with control signal to camera unit. At left bottom, both are connected with a one-way arrow from SNMP agent box to management station (video signal). )
Figure 1: CCTV System Communications Interface CCTV System Operations
Typically three operations are used in a CCTV system:
These operations are carried out by SNMP messages; SET and GET. This will be discussed in the next Module A317b - Understanding Requirements for CCTV Systems Based on NTCIP 1205 Standard.
National Transportation Communications for Intelligent Transportation System Protocol (NTCIP)
The NTCIP is a framework of a family of standards which serves two categories of needs: center to field communications for devices and center to center communications for information exchange among centers. The NTCIP framework uses SNMP as a communications protocol does which controls a device indirectly (implicitly using commands (GET, SET).
Management System (Station)/SNMP Agent Model
A management station is a computer or computer network that houses a SNMP Manager which interact with the device via the defined interface to realize the features of the device, such as a Traffic Management System referenced in NTCIP device standards. The SNMP Agent is a software module that resides in a device firmware and interfaces with both the device and the central SNMP manager. CCTV system works as a Manager/Agent model.
Objects and Management Information Base (MIB)
A MIB is a set of device object definitions or data elements. The object has a definite structure provided by the format called Abstract Syntax Notation 1 (ASN.1), which is an international standard for defining objects.
An object defines the attributes, properties and controllable features of the devices on a network. The device is remotely monitored, configured and controlled by manipulating the content of an object that defines a function. The following is an example of a CCTV system object for presets.
The above example of a CCTV system object structure details include an unique name-rangemaximumPreset; the syntax field which provides value-how many presets (should be more than 1, less than 255 but 0 will not deliver preset capability),this is a Mandatory-required object and it can only be read. The description explains what it will do for system and last line shows Object's unique identification-location in the MIB tree-under which node it can be found). We are able to infer from this details of the object-namely N number of presets are to be provided by the system.
For example, a large size TMC Freeway management operation may select 50 presets, while a simple operation may just have 5 presets for operation.
2. User Needs and Related Operational Considerations
IEEE standard 1362 defines user need as: "a user requirement for a system that a user believes would solve a problem experienced by the user." (Note: the use of word requirement here does not imply system requirements)
The NTCIP family of device standards refers to user need as "The business or operational problem (opportunity) that must be fulfilled in order to justify purchase or use." While this is termed a "user need' within the NTCIP community, it reflects needs of all stakeholders."
By establishing user needs, users declare what they want from the intended system and system must satisfy stated user needs. If this step is not taken carefully, the outcome could be an incomplete system and a non-interoperable system may result. To avert such adverse outcomes, we must ensure that user needs for all concerned ITS standards are identified and properly written in the specification.
The user needs identified in the NTCIP device standards do not reflect all the possible user needs that may be desired for that device. The user needs listed only reflect those features that are commonly desired by stakeholders and thus are supported by the device standard. Each procuring agency may have additional user needs not identified by the standard, and those user needs will have to be expressed in the procurement specification.
Operational environment - The operational environment defines how data may be exchanged across the communications interface.
Features - The features identify and describe the various functions that users may want the device to perform. These features are derived from the high level user needs identified in the problem statement but are refined and organized into a more manageable structure that form the basis of the traceability tools. The operational environment and features are collectively called the user needs.
How User Needs affect Interoperability
Off-the-shelf interoperability and interchangeability can only be obtained by using well documented user needs, along with their corresponding requirements and design that are broadly supported by the industry as a whole. Designing a system that uses environments or features not defined in a standard or not typically deployed in combination with one another will inhibit the goals of interoperability and interchangeability, especially if the documentation of these user needs is not available for distribution to system integrators. The standards allow implementations to support additional user needs in order to support innovation, which is constantly needed within the industry; but users should be aware of the risks involved with using such environments or features.
For an agency to achieve interoperability and interchangeability, procurement must ensure that a careful assessment of user needs is done and common set of needs are established as a first step. By defining the meaning of the words in the common language (dictionary) and their effect upon advice (functionality), the NTCIP standards such as NTCIP 1205 achieve interchangeability. The standards establish a minimum level of common functionally. While a system and its components are free to go beyond the common functionality, subscribing to the NTCIP standards ensures that a level of interchangeability is always present.
For example user needs shown here states that a TMC desires to exchange messages with other centers. Without this user need written in the specification, system developers will be unaware of the users' intentions and underlying operational needs. That will be a problem to correct later on. The user needs are central to system development and if we missed them or designer misrepresented user needs, incomplete or non-interoperable systems could result.
What is important is that the agency personnel understand what they want their devices and systems to do for them because that will provide input to the application of the mixed standards for their procurement process.
User Needs Dictate Features
A feature is a behavior of the device. A device has more than one feature to serve desired (assigned) functions. The features identify and describe the various functions that users may want the device to perform. These features are derived from the high level user needs identified in the problem statement but are refined and organized into a more manageable structure that forms the basis of the traceability table; the Protocol Requirements List (PRL). User Needs Affect Interchangeability (Vendor-independence)
A condition which exists when two or more items possess such functional and physical characteristics as to be equivalent in performance and durability, and are capable of being exchanged one for the other without alteration of the items themselves, or adjoining items, except for adjustment, and without selection for fit and performance. (National Telecommunications and Information Administration, U.S. Department of Commerce)
According to the NTCIP Guide,, interchangeability reflects the capability to exchange devices of the same type on the same communications channel and have those devices interact with others devices of the same type using standards-based functions. With interchangeability, system components can be changed out (switched) with similar components from different vendors because they possess common functional and physical characteristics. An example of interchangeability is a signal controller from different manufacturers interacting with each other to provide traffic signal coordination along an arterial throughway.
Operational Considerations Related to CCTV System User Needs
(Ref. Author: Paul Olson, FHWA Resource Center)
System U sers
1 A pre-specified position where a camera is pointed to a fixed point in space. A preset includes pan, tilt, and zoom parameters. Presets are typically programmed by manually adjusting the camera position and lens zoom setting followed by initiating a save command from the camera control system. Source NTCIP 1205
Camera Tours Operational Issues
3. Criteria for Writing CCTV User Needs
Why are we Writing CCTV System User Needs?
A procurement writer is required to develop a specification to acquire a standards-based system by deriving user needs from standards. The problem occurs when a project needs to deploy standards without SEP content. These standards do not contain documented user needs from which an agency can select or customize. There are several such standards (both devices and systems) developed. For example both the traffic controller and CCTV standards do not contain user needs listing.
As stated earlier, a user need describes a business or operational problem (opportunity) that must be fulfilled in order to justify purchase or use. This representation may occur in many ways expressed by different users with varied understanding of the baseline case. This could lead to an incomplete system development or ambiguous statements confusing developers. To avoid such happenings, users must understand how to write user needs and put them in proper context and meaning of desired interoperability and/or need for vendor independence.
Criteria for Writing a Well-formed User Need
In general, ITS Standards with SEP content have followed the following SE criteria to define user needs and we need to understand this and apply to user needs extracted from standards without SEP content.
The above criterion is used in the process of extracting and writing a user needs from the standards without SEP content as discussed in the next section.
4. NTCIP 1205 CCTV Conformance Groups
A conformance group is defined as a basic unit of conformance (NTCIP standard) and contains both mandatory and optional objects. Each NTCIP device standard completed without SEP content has a section on conformance groups. A Conformance Statement (in the form of a Table) lists required conformance groups to comply with subject device standard. Please note that NTCIP 1201 Global Objects (GO) is recently updated (Users are advised to use updated standards).
Table 4-2: Conformance Statement Table
Example: Motion Control Conformance Group (Section 4.1.3)
Example of the Motion Control lists required objects-mandatory. The conformance requirement for each object within this CG is shown.
The Motion Control Conformance Group shall consist of the following objects:
Extracting CCTV User Need from the NTCIP 1205 Standard
Step-1: Read: Those Standards without SEP content do have MIB and Conformance groups listed in documentation. They represent "functions" or user needs that are served by functions. (In this example, go to NTCIP 1205 CCTV and check the details).
Step-2: Recognize: CG have collection of objects, contained in MIB, match them to what you are looking for or purpose they serve. [Go to CG Table 4.2]
Step-3: Infer: Infer from CG Motion Control with MIB objects, a need to control pre-sets, also know that mandatory CG must be selected so, UN will be mandatory. The capacity (how many pre-sets you need) is controlled by a range in the Object definition (see below). User desiring interoperability will have to select same range support at minimum. Description of an object also aids in the process.
(Extended Text Description: Maximum Number of Presets Parameter. The text of this figure is as follows:
Additional Text Description: A line from the DESCRIPTION paragraph points to the table cell labeled "UN 1.2" )
Step-4: Write: Give a unique ID and title [write criteria state that UN must be uniquely identifiable]; there is a rationale to provide for use of camera to monitor conditions an operational need UN 1.0, and a major desired capacity, to control CCTV (UN 1.1).
Using the above steps (READ-RECOGNIZE-INFER-WRITE) and prescribed Criteria discussed above a set of user needs are organized.
Validate CCTV User Needs Traceability
Each user need shall be traced to one or more functional requirements and each functional requirement shall be derived from at least one user need. This traceability is shown in the PRL for SEP based device standards, in conformance groups in standards without SEP content and in NRTM (Needs to Requirements Traceability Matrix) in system standards. Each user need shall be traced to one or more functional requirements and each functional requirement shall be derived from at least one user need. This traceability is shown in the PRL for SEP based device standards, in conformance groups in standards without SEP content and in NRTM (Needs to Requirements Traceability Matrix) in system standards.
5. Video Formats
Video format and related standards deal with conversion, storage and compression techniques used for transmission of images. These standards are outside of the transportation domain or ITS or NTCIP activities. They are developed and used by the Internet community for video-audio and data transmission. Some related information is stated below:
NTCIP 1205 standard does NOT cover these formats but they are presented here for awareness purpose:
5. Glossary [These terms are linked to user needs]
7. Study Questions
Question 1: Which of the following applies to the NTCIP 1205 standard?
Question 2: Which of the following is NOT a true statement related to traffic management?
Question 3: The NTCIP 1205 CCTV standard does not provide the documented user needs for the acquisition process. What is the Best Source of User Needs?
Question 4: Which of the following is a well-formed CCTV user need?
Question 5: Which of the following is NOT a true statement related to the NTCIP 1205 CCTV standard?