3. LA BELLEZA DEL CUERPO EN LA PUBLICIDAD Y CULTURA TELEVISIVA
3.3 Los datos hablan solos
Determine PPS Objectives Design PPS Physical Protection Systems
Detection Delay Response
Response Force Access
Delay Exterior Sensors
Interior Sensors
EASI Model Adversary Sequence Diagrams Computer Models Risk Assessment Response Force
Communications Alarm Assessment
Alarm
Communication & Display Entry Control
Analyze PPS Design
Analysis/Evaluation
Final PPS Design
Redesign PPS Facility
Characterization
Threat Definition
Target Identification
The designer now knows the objectives of the PPS, that is, what to protect and against whom. The next step is to design the new system or characterize the existing system. If designing a new system, we must determine how best to integrate people, procedures, and equip-ment to meet the objectives of the system.
Once a PPS is designed or characterized, it must be analyzed and evaluated to ensure that it meets the physical protec-tion objectives. The PPS design must allow the combination of protection elements working together to assure protection rather than regarding each feature sepa-rately. Implementation of the PPS design then addresses the systematic and inte-grated protection of assets in anticipation of adversary attacks, rather than in reaction to attacks after they occur.
If designing a new PPS, the designer must determine how best to combine such elements as fences, barriers, sensors, procedures, communication devices, and security personnel into a PPS that can achieve the protection objectives. The resulting PPS design should meet these
objectives within the operational, safety, legal, and economic constraints of the facility. The primary functions of a PPS are detection of an adversary, delay of that adversary, and response by security personnel (guard force). These functions and some of their components are shown in Figure 5.1.
Certain guidelines should be observed during the PPS design. A PPS system performs better if detection is as far from the target as possible and delays are near the target. In addition, there is close asso-ciation between detection (using exterior or interior sensors) and assessment. It is a basic principle of security system design that detection without assessment is not detection, because without assessment the operator does not know the cause of an alarm. If the alarm is the result of trash blowing across an exterior area or lights being turned off in an interior area, there is no need for a response, since there is no valid intrusion (i.e., by an adversary).
Another close association is the relation-ship between response and response force communications. A response force cannot 57
PPS Functions
Detection
• Intrusion Sensing • Barriers
• Response Force
• Interruption:
– Communication to Response Force – Deployment of Response Force
• Alarm Communication
• Alarm Assessment
Delay Response
Figure 5.1 Functions of a Physical Protec-tion System. The PPS funcProtec-tions include detection, delay, and response
respond unless it receives a communi-cation call for a response. These and many other particular features of PPS components help to ensure that the designer takes advantage of the strengths of each piece of equipment and uses equip-ment in combinations that allow them to complement each other and protect any weaknesses.
Design of the PPS begins with a review and thorough understanding of the protec-tion objectives that the designed system must meet. This can be done simply by checking for required features of a PPS, such as intrusion detection, entry control, access delay, response communications, and a protective force. However, a PPS design based on required features cannot be expected to lead to a high-performance system unless those features, when used together, are sufficient to assure adequate levels of protection. Feature-based designs only check for the presence of a partic-ular number or type of component, with no consideration for how effectively the component will perform during an adver-sary attack. A good PPS is designed using components that have validated perfor-mance measures established for opera-tion. Component performance measures are combined into system performance measures by the application of system modeling techniques.
Physical Protection System Design A system may be defined as a collection of components or elements designed to achieve an objective according to a plan.
The ultimate objective of a PPS is to prevent the accomplishment of overt or covert malevolent actions. Typical objec-tives are to prevent sabotage of critical equipment, theft of assets or information from within the facility, and protection of people. A PPS must accomplish its objec-tives by either deterrence or a combination of detection, delay, and response. Listed below are the component subsystems that provide the tools to perform these func-tions. Each of these component subsystems will be discussed in detail in the remainder of Part Two.
Functions and Component Subsystems Detection
Exterior/Interior Intrusion Sensors Alarm Assessment
Alarm Communication and Display Entry Control Systems
Delay
Access Delay Response
Response Force
Response Force Communications
The system functions of detection and delay can be accomplished by the use of either hardware and/or guards. Guards usually handle response, although auto-mated response technologies are under development. There is always a balance between the use of hardware and the use of guards. In different conditions and appli-cations, one is often the preferable choice.
The key to a successful system is the inte-gration of people, procedures, and equip-ment into a system that protects assets from threats. This integration requires a tradeoff analysis of cost versus perfor-mance, so if a designer decides to use more guards and less hardware, there should be a corresponding analysis that supports this
Physical Protection System Design 59
decision. Keep in mind that humans are generally not good detectors, while equip-ment is very good at the repetition and boredom associated with constant close monitoring.
Detection, delay, and response are all required functions of an effective PPS.
These functions must be performed in this order and within a length of time that is less than the time required for the adversary to complete his or her task. A well-designed system provides protection-in-depth, minimizes the conse-quence of component failures, and exhibits balanced protection. In addition, a design process based on performance criteria rather than feature criteria will select elements and procedures according to the contribution they make to overall system performance. Performance criteria are also measurable, so they can help in the anal-ysis of the designed system.
PPS Functions
The primary PPS functions are detection, delay, and response. It is essential to consider the system functions in detail, since a thorough understanding of the defi-nitions of these functions and the measure of effectiveness of each is required to eval-uate the system. It is important to note that detection must be accomplished for delay to be effective. Recall that the highest priority system goal is to protect critical assets from theft or sabotage by a malevo-lent adversary. For a system to be effective at this objective, there must be notifica-tion of an attack (detecnotifica-tion), then adversary progress must be slowed (delay), which will allow the response force time to inter-rupt or stop the adversary (response).
Detection
Detection is the discovery of an adver-sary action. It includes sensing of covert
or overt actions. In order to discover an adversary action, the following events need to occur:
1. A sensor reacts to a stimulus and initiates an alarm.
2. The information from the sensor and assessment subsystems is reported and displayed.
3. A person assesses information and judges the alarm to be valid or invalid. If assessed as a nuisance alarm, detection has not occurred.
Detection without assessment is not considered detection. Assessment is the process of determining whether the source of the alarm is due to an attack or a nuisance alarm.
These events are depicted in Figure 5.2 and show that detection is not an instan-taneous event. Included in the detec-tion funcdetec-tion of physical protecdetec-tion is entry control. Entry control allows entry to authorized personnel and detects the attempted entry of unauthorized personnel and material. The measures of effective-ness of entry control are throughput, false acceptance rate, and false rejection rate.
Throughput is defined as the number of authorized personnel allowed access per unit time, assuming that all personnel who attempt entry are authorized for entrance.
False acceptance is the rate at which false identities or credentials are allowed entry, while false rejection rate is the frequency of denying access to authorized personnel.
The measures of effectiveness for the detection function are the probability of sensing adversary action, the time required
Sensor Activated
Alarm Signal Initiated
Alarm Reported
Alarm Assessed
Figure 5.2 Detection Functions in a PPS.
Detection starts with sensor activation and ends with assessment of the alarm to deter-mine the cause
for reporting and assessing the alarm, and nuisance alarm rate. A sensor acti-vates at time T0, then at a later time a person receives information from the sensor and assessment subsystems. If the time delay between when the sensor acti-vates and when the alarm is assessed as short, the probability of detection, PD, will be close to the probability that the sensor will sense the unauthorized action, PS. The probability of detection decreases as the time before assessment increases.
Figure 5.3 shows that a long time delay between detection and assessment lowers the probability of detection, because the more the time required to make an accu-rate assessment, the less likely it will be that the cause of the alarm is still present.
For example, if sensor alarms are assessed by sending a guard to the sensor location, by the time the guard arrives there may no longer be an obvious alarm source. In this case, the delay between sensor initia-tion and assessment was so lengthy that no assessment could be made. This is why PD decreases. In addition, the delay between detection and assessment favors the adversary due to the further progres-sion of the adversary toward the target before the response force has been notified of an attack.
Response force personnel can also accomplish detection. Guards at fixed posts or on patrol may serve a vital role in sensing an intrusion. An effective assessment system provides two types of information associated with detection:
information about whether the alarm is valid or nuisance, and details about the cause of the alarm—what, who, where, and how many. However, even when assisted by a video-assessment system, humans do not make good detectors.
Studies have shown that brief instances of movement are missed by 48% of human observers using video monitors (Tickner and Poulton, 1973).
An additional performance measure of sensors is the nuisance alarm rate.
A nuisance alarm is any alarm that is not
1 Ps*
T0
Assessment Time
*Probability that sensor alarms Probability of Detection PD
T1 T2 PD
T3
Figure 5.3 Relationship between Assess-ment Time and Probability of Detection.
The probability of detection will decrease as assessment time increases
caused by an intrusion. In an ideal sensor system, the nuisance alarm rate would be zero. However, in the real world all sensors interact with their environment and they cannot discriminate between intrusions and other events in their detection zone.
This is why an alarm assessment system is needed: not all sensor alarms are caused by intrusions.
Usually nuisance alarms are further clas-sified by source. Both natural and indus-trial environments can cause nuisance alarms. Common sources of natural noise are vegetation (trees and weeds), wildlife (animals and birds), and weather condi-tions (wind, rain, snow, fog, lightning).
Industrial sources of noise include ground vibration, debris moved by wind, and elec-tromagnetic interference. False alarms are those nuisance alarms generated by the equipment itself (whether by poor design, inadequate maintenance, or component failure).
Delay
Delay is the second function of a PPS. It is the slowing down of adversary progress.
Delay can be accomplished by people,
Physical Protection System Design 61
Delay
Provide Obstacles to Increase Adversary Task Time
Barriers Response Force (Guards)
Figure 5.4 Delay Function. Delay compo-nents include barriers and members of the response force. Barriers include active and passive barriers
barriers, locks, and activated delays. The response force can be considered elements of delay if they are in fixed and well-protected positions. The measure of delay effectiveness is the time required by the adversary (after detection) to bypass each delay element. Although the adversary may be delayed prior to detection, this delay is of no value to the effective-ness of the PPS since it does not provide additional time to respond to the adver-sary. Delay before detection is primarily a deterrent. There are some situations where barriers are placed before detec-tion; however, this application is meant to force adversaries to change or abandon their tactic. For example, the use of speed bumps or placement of jersey bounce barriers along the sides of a road will slow down or prevent an adversary in a vehicle from leaving the road. Figure 5.4 summa-rizes the function of delay in a PPS.
Response
The response function consists of the actions taken by the response force to prevent adversary success. Response consists of interruption and neutraliza-tion. Interruption is defined as a suffi-cient number of response force personnel arriving at the appropriate location to stop the adversary’s progress. It includes the communication to the protection force
Communicate to Response
Force
Deploy Response
Force
Interrupt Adversary
Attempt
Figure 5.5 Response Function. Response components include communication, proper deployment of the response force, and interruption of the adversary prior to attack completion
of accurate information about adversary actions and the deployment of the response force. An additional measure of response force effectiveness, neutral-ization, is also used in some high-security applications. Neutralization is a measure of the outcome of a confronta-tion between the response force and adversaries. Neutralization can range from chasing away vandals up through an armed engagement with well-armed attackers.
This concept will be discussed further in Chapter 12, “Response.” The measures of response force effectiveness include the time between the receipt of communica-tion of adversary accommunica-tion and the inter-ruption of the adversary action (response force time), and the success of the response team after interruption (neutralization) function, shown in Figure 5.5.
The effectiveness measures for response communication are the probability of accu-rate communication and the time required for communication. The time after infor-mation is initially transmitted may vary considerably depending on the method of communication. After the initial period, the probability of valid communication begins to increase rapidly. As shown in Figure 5.6, with each repeat, the proba-bility of correct and current data being communicated is increased. There can be some delay in establishing accurate communication due to human behavior.
On the first attempt to communicate, the operator is alerted that there is a call, but may not have heard all the relevant inform-ation. Then a request for a second trans-mission is made to repeat the information,
Probability of correct communication increases with each transmission of information.
Time
First Notification to Response Force Second Notification
Clarification
1
0
Probability of Communication
Figure 5.6 Variation of Probability of Com-munication with Time. As the time to esta-blish accurate communication increases, the probability of communication increases
and finally, the operator understands the call and asks for clarification.
Deployment describes the actions of the protective force from the time communi-cation is received until the force is in position to interrupt the adversary. The effectiveness measure of this function is the probability of deployment to the adver-sary location and the time required to deploy the response force.
Relationship of PPS Functions
Figure 5.7 shows the relationships between adversary task time and the time required for the PPS to do its job. The total time required for the adversary to accomplish the goal has been labeled Adversary Task Time. It is dependent upon the delay provided by the PPS. The adversary may begin the task at some time before the first alarm occurs, which is labeled on the diagram as T0. The adversary task time is shown by a dashed line before this point because delay is not effective before detection. After the alarm, the alarm information must be reported and assessed to determine if the alarm is valid. The
Begin Action
Task Complete
Adversary Task Time
First Alarm
Detect Response
Time
T0 TA TI TC
Adversary Interrupted
Alarm Assessed
PPS Time Required
Figure 5.7 Interrelationship of PPS Func-tions. Detection begins upon receipt of the first alarm and ends when the alarm is assessed. The delay function slows down the adversary in order to allow the response force time to deploy. The PPS must provide enough time for the response force to stop the adversary from success-fully completing the task
time at which the alarm is assessed to be valid is labeled TA, and at this time the location of the alarm must be commu-nicated to the members of the response force. Further time is then required for the response force to respond in adequate numbers and with adequate equipment to interrupt adversary actions. The time at which the response force interrupts adver-sary actions is labeled TI and adversary task completion time is labeledTC. Clearly, in order for the PPS to accomplish its objectives, TI must occur before TC. It is equally clear that the first alarm should occur as early as possible and T0 (as well asTAandTI) should be as far to the left on the time axis as possible.
Consideration of chemical, biological, and radiological attacks does not change the time relationship among the PPS func-tions. There still must be detection with
Physical Protection System Design 63
enough time to allow whatever response is required—shelter-in-place, evacuation, put on protection equipment, and so on.
Some facilities have used different strate-gies to address these attacks, such as always filtering incoming air, but the filters must be replaced periodically to maintain effective capability. In this case, sensors can still provide detection, and delay components include filters or turning off the heating and ventilation system to slow the spread of the agent. The basic prin-ciple is the same—the spread of the agent must be delayed so there is enough time to implement whatever response is desired.
Implementation of the appropriate detec-tion, delay, and response elements must be considered for the overall system against the defined threat.
Characteristics of an Effective PPS The effectiveness of the PPS functions of detection, delay, and response and their relationships have been discussed.
In addition, all the hardware elements the system must be installed, maintained, and operated properly. The procedures of the PPS must be compatible with the facility procedures and integrated into the PPS design. Training of personnel in policies, procedures, and operation of equipment is also important to system effectiveness.
Security, safety, and operational objectives must be accomplished at all times. A well-engineered PPS will exhibit the following
Security, safety, and operational objectives must be accomplished at all times. A well-engineered PPS will exhibit the following