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Prueba 1 > ASIS CPP - Physical Security (Part 1) > Flashcards

ASIS CPP - Physical Security (Part 1) Flashcards

1
Q

CPTED

8 Main categories of Physical Security Measures

A
  1. CPTED (Crime-Prevention Through Environmental Design
  2. Physical barriers & site hardening
  3. Physical entry & access control
  4. Security Lighting
  5. Intrusion Detection
  6. Video Surveillance
  7. Security Personnel
  8. Security policies & procedures
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2
Q

CPTED

What can lead to a reduction in the opportunity fear & incidence of predatory, stranger-to-stranger type crime?

A

Proper design & effective use of the built environment

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3
Q

CPTED

Should be divided into smaller, more clearly defined areas or zones (defensible space, per Oscar Newman)

A
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4
Q

CPTED

What can also result in an improvement of the quality of life - how & where we live, work, & play?

A

CPTED

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5
Q

CPTED

CPTED should be integrated into…?

A

The design & function of the buildings or location

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6
Q

CPTED

All Human Space…

A

Has some designated purpose

Has social, cultural, legal or physical definitions that prescribe the desired & acceptable behaviors

Is designed to support & control the desired & acceptable behaviors

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7
Q

CPTED

CPTED is the design or redesign of a venue to reduce crime opportunity & fear of crime through?

A

Natural Means

Mechanical Means

Procedural (organizational) means

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8
Q

CPTED

At its core, CPTED is based on common sense & a heightened awareness about how people use their space for legitimate & criminal intentions

A
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9
Q

CPTED

3 Classes of CPTED Strategies

A
  1. Mechanical measures
  2. Organizational measures
  3. Natural or architectural measures
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10
Q

CPTED Strategies

A

Natural access control

Natural surveillance

Natural territorial reinforcement

Management & maintenance

Legitimate activity support

Compartmentalization

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11
Q

CPTED

Methods for implementing CPTED

A

Organized methods (staffing)

Mechanical methods (technical products)

Natural methods (site planning, design, landscaping, signage)

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12
Q

CPTED

Once the first window is broken, vandalism and/or other crime quietly follow if it is not prepared

A

Broken Window Theory

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13
Q

CPTED

CPTED is congruent with the 3 D’s

A

Deterring

Detecting

Delaying aggressors

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14
Q

CPTED

Preventing crime & losses is inherent in many human functions behaviors & activities

A
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15
Q

CPTED

CPTED security standards focus on 4 categories

A
  1. Perimeter & exterior security
  2. Entry security
  3. Interior security
  4. Security planning
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16
Q

CPTED

Types of CPTED Security Zones

A
  1. Unrestricted zones
  2. Controlled zones - authorized personnel in these general areas
  3. Restricted zones - authorized personnel in these specific areas
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17
Q

CPTED

Deterrence is achieved through…?

A

Measures that potential adversaries perceive as too difficult to defeat

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18
Q

CPTED

For the security professional, CPTED is a set of management tools targeting…?

A

Places

Behavior

Design & Use of Space

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19
Q

CPTED

What is more cost-effective than making changes after construction starts

A

Integrating CPTED during the initial planning

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20
Q

CPTED

Whenever possible, security planning should begin during…?

A

Site Selection

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21
Q

CPTED

CPTED is intended to be integrated throughout the construction process

A

Programming

Schematic Design (SD)

Design Development (DD)

Construction documents or working drawings (CD)

Bids for construction & selection of contractor (RFP)

Security needs should be addressed int he programming phase

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22
Q

CPTED

Establish a secure perimeter around the building as far out as possible… setbacks how far?

A

100 ft. is suggested

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23
Q

CPTED

Where should you position concrete flower planters etc…?

A

Near curbs less than 4 ft between them to block cars

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24
Q

CPTED

Locate parking as far from the building as practical & place it within view of occupied rooms or facilities

A
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25
Q

CPTED

Landscaping Considerations

A

Low growing plants should be set back 1 yard from the edge of paths or walkways

Low-growing shrubs should be kept no higher than 32” in height

Tree canopies should be trimmed up to 8’ to provide a clear line of the site & reduce hiding spots

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26
Q

CPTED

Parking garages should be equipped with what?

A

  • 3 ft. or higher shrubs/trees should be 10-15 ft. from the structure
  • Booths should have 360 degrees visibility & a means of communication
  • No public restrooms but should be within view of the booth
  • One vehicle entry/exit should be used if possible (based on traffic volume)
  • Open-walled, upper levels to allow natural surveillance & permit hearing of calls for help
  • Egress only exterior pedestrian doors
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27
Q

CPTED

Parking Garages (ctd…)

A

  • Potholes in solid walls for visibility
  • Stairwells & elevators in a central location visible from both
  • Stairwells visible from exterior & offering no hiding place & no roof access
  • Elevators with glass for exterior visibility along the exterior of the facility
  • Access only to the lobby from the garage elevators or stairs
  • Adequate lighting
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28
Q

Access Control

Refers to the process of managing databases or other records & determining the parameters of authorized entry, such as who or what will be granted access when they may enter where access will occur

A

Access Control

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29
Q

Access Control

Categories of Access Control

A

Manual

Machine Aided

Automated

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30
Q

Access Control

Types of attacks used to defeat access controls

A

Deceit

Direct Physical Attack

Technical Attack

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31
Q

Entry Control

An entry control subsystem includes the following performance measures…

A

Throughout

Error Rates

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32
Q

Entry Control

An Entry Control Subsystem

A
  • is not an access control system
  • Is part of the detection system
  • Allows the movement of authorized personnel & material into & out of facilities
  • Detects & possibly delays movement of unauthorized personnel & contraband
  • Refers to the physical equipment used to control the movement of people or material into an area
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33
Q

Entry Control

Objections of an entry control system used for physical protection are…

A
  • To permit authorized persons to enter & exit
  • To detect & prevent the entry or exit of contraband material (weapons, explosions, unauthorized tools, or critical assets)
  • To provide information to security personnel to facilitate assessment & response
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34
Q

Entry Control

Verification of authorization of personnel to enter a controlled area is usually based on…

A
  1. Carrying a valid credential (what you have)
  2. Knowing a valid PIN (what you know)
  3. Possessing the proper, unique physical characteristics on file (who you are)
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35
Q

Badge Technologies

Magnetic Stripe (“mag stripe”)

A
  • Widely used in commercial credit/debit cards
  • Low-coercivity (“LoCo”) cards are 300 oersteds; easy to erase; typical of credit/debit cards
  • High-coercivity (Hi - CO) cards are 2500 to 4000 oersteds; hard to erase, but can be done with rare_earth magnets; typical of company badges
  • Easily forged, duplicated (can use proprietary encoding schemes but not common)
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36
Q

Access & Entry Control

Badge Technologies

A
  • Magnetic Stripe
  • Bar Code
  • Proximity
  • Smart Card
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37
Q

Access/Entry Control

Badge Technologies Proximity…

A
  • Small RF transponder/transmitter is powered by an onboard battery (active) or it is energized by the card reader (passive)

- Low-frequency badges are in the 125 KHz range

  • High-frequency badges range from 2.5 MHz to over 1 GHz
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38
Q

Access/Entry Control

Badge Technologies - Smart Card

A
  • Gold contacts on the surface of the card allow for communication with a reading device
  • Contactless smart cards use RF communications & do not have the gold contacts
  • Main advantages: Large memory & its high degree of resistance to forgery or compromise
  • Ability to encrypt communications
  • Can be prohibitively expensive
  • Homeland Defense Presidential Directive (HSPD 12)
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39
Q

Access/Entry Control

Personal Identity Verification System

Biometrics

A
  • Corroborate claimed identities on the basis of one or more unique physical biometric characteristics of the individual
  • Can differentiate between: verification & recognition
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40
Q

Access/Entry Control

Personal identify verification systems

All personal identity verification systems consider 3 things

A
  • The uniqueness of the feature used for identification
  • The variability of the characteristic
  • The difficulty of implementing the system that processes the characteristic
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41
Q

Personal identity verification systems

Type 1 error rate:

A

False rejection of a valid user

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42
Q

Personal identity verification systems

Type II Error rate

A

False acceptance of an invalid user

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43
Q

Access/Entry Control

Personal identity verification systems

Equal error rate

A
  • Cross-over point where Type 1 & Type 2 errors are equal

- Not necessarily the point at which the device should be operated

- Not the lowest point for either type of error

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44
Q

Access/Entry Control

Personal identity verification systems

Finger Prints

A
  • Still considered one of the most reliable means of distinguishing one individual from another
  • Most systems use image processing & pattern recognition

Minutia points

Ridge endings

Bifurcations

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45
Q

Access/Entry Control

Personal identity verification systems

Hand/Finger Geometry

A
  • Characterizes the shape of the hand
  • Measures 3-dimensional features of the hand such as the widths & lengths & the thickness of the hand
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46
Q

Personal Identity Verification System

Eye Pattern

A
  • Imaging of iris by a video camera
  • Operates in the recognition mode
  • 10 - 12” read distance (no physical contact)
  • 2% of population cannot be enrolled due to blindness or other eye issues
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47
Q

Personal identity verification system

Face

A

- Utilize distinguishing characteristics of the face

- Captured with video camera or thermal image

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48
Q

Personal identity verification system

Voice

A
  • Speech measurements: waveform envelope, voice pitch period, relative amplitude spectrum, resonant frequencies of the vocal tract
  • Low security, easily deployed, more public acceptance (low distrust)
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49
Q

Personal identity verification system

Handwriting

A
  • Used for many years by the bank
  • Signatures can be easily forged
  • Handwriting dynamics include displacement velocity & acceleration
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50
Q

Access/Entry Control

Access control barriers include…

A

Doors

Gates

Turnstiles

Elevators

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51
Q

Access/Entry Control

Vehicle access controls are…

A

Manual

Electronic

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52
Q

Access/Entry Control

Electro-Mechanical Lock Types

A
  • Electric deadbolts
  • Electric latch
  • Electric strike
  • Electric lockset
  • Exit device
  • Electromagnetic lock
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53
Q

Access/Entry Control

Device unlocks upon loss of power (but may stay latched - “positive latching”)

A

Fail Safe

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54
Q

Access/Entry Control

Device locks upon loss of power

A

Fail Secure

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55
Q

Access/Entry Control

Single action / motion egress

A

One action/motion required to release door to exit

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56
Q

Alarm Communications & Display (AC&D)

The part of a PPS that transports alarm & assessment information to a central point & presents the information to a human operator

A

AC&D: Alarm Communication & Display

57
Q

The most important measure of AC&D Effectiveness?

A

How well it quickly & clearly communicates alarm data from sensors to the system

58
Q

AC&D

Two critical elements of alarm communication & display

A
  • Transportation or communication of data

- Presentation or display of that data to a human operator in a meaningful manner

59
Q

AC&D

When an alarm occurs, the AC&D system must communicate to the operator the following information

A

- When an alarm has occurred

- What or who caused the alarm

- When the alarm happened

60
Q

AC&D

Security communications require the following assurances

A

- The integrity of the communications medium (availability of the message path)

- The integrity of the message (complete & errorless transmission of the data)

- Timeliness of the transmission (data communication within an appropriate time frame)

- Message security (accessibility of the communication to authorized persons only)

61
Q

AC&D

Communications Security - Line Protection

A

- Outside lines should be installed underground

- Inside wiring should be encased in conduit

62
Q

AC&D

Communication Security - Line Supervision

A

Simplest line supervision: End-of-line (EOC) resister (detects open circuit, ground, wire-to-wire short)

63
Q

AC&D

Communication Security - Scramblers

A
  • Disguise interceptible communications
  • 2 characteristics of voice that can be scrambled

frequency (pitch of voice) (most typically scrambled)

Amplitude (loudness)

64
Q

AC&D

Transmission of Alarm Signals

A

Alarm signals may be transmitted on an unshielded pair of direct current (DC) Conductors

65
Q

AC&D

Signals also may be transmitted on…

A

Lines installed to carry electric power

66
Q

AC&D

Optical Fiber

A

A strand of high-purity, spun glass, typically about the thickness of a human hair

67
Q

AC&D

Optical fibers can be used to carry…

A

- Voice-grade signals

- Video signals

- Digital or data grade signals

68
Q

AC&D

Optical fibers differ from a conventional metal wire in several ways

A
  • Not affected by (EMI) or (RFI)
  • Don’t carry electrical current nor radiate signals
  • Can carry many more multiplexed messages
  • Much smaller & lighter than conventional
  • Flexible & can take an irregular course from P to P
  • Not vulnerable to interception by acoustical or inductive coupling
69
Q

AC&D

Optical Fiber

A

Optical fiber is less expensive than copper

70
Q

AC&D

Video Transmission Methods

A

Coaxial Cable

Telephone Lines

Optical Fiber

Dedicated Twisted Pair

DC Wire

71
Q

AC&D

Video Transmission Methods

A

No processing required if transmission distance is short enough, typically 1,000 ft.

72
Q

Video Transmission Methods

The transmission distance without amplification is 1 mile or more

A

Optical Fiber

73
Q

AC&D

Good performance can be achieved at wire distances of up to 4,000 ft.

A

Dedicated Twisted Pair

74
Q

AC&D

Video signals cannot be transmitted directly on DC lines

A

DC Wire

75
Q

AC&D

3 Types of line transmission used in electronic protection systems

A

Loop

Point-to-Point

Multi-plexed

76
Q

AC&D

Two methods used to separate multiplexed signals

A
  • Time division multiplexing (TDM)
  • Frequency division multiplexing (FDM)
77
Q

AC&D

A wireless communication requires

A
  • A transmitter to furnish radio frequency energy
  • An antenna to radiate the energy into the atmosphere
  • A receiver
  • Power for the transmitter & receiver
78
Q

AC&D

Wireless Transmission

A

Any unscrambled or unencrypted communication transmitted by wireless technology should be considered available for interception

79
Q

AC&D

Voice radio (2-way radio) cost & power are determined by

A
  • The distance required to communicate
  • Barriers in the transmission path
  • Signal interference in the area
80
Q

AC&D

Microwave Transmission

A

- Operates between 30 - 300 GHz

- Requires microwave generator, power, amplifier, modulation, antenna

- One-way & two-way communications

- Often require FCC licenses

- Penetrates rain, fog, snow & man-made noise

- Used in television, multiplexed telephone, multiplexed alarm & high-speed data transmissions

- Line-of-sight (LOS) required

81
Q

AC&D

Laser Communication

A

- Light amplification by stimulated emission of radiation (LASER)

- Laser light is modulated at a very rapid rate

- A photo-detector at the receiver demodulates the laser

- Virtually impossible to intercept without detection

- A 4-mile transmission line of sight

- Reflected can be used but the resolution is reduced

- interference from snow, fog, and rain

- No FCC license required

82
Q

AC&D

Most common causes of wireless interference

A

- Signals from other transmitters

- Industrial & atmosphere noise

83
Q

Intrusion Detection

The process of detecting a person or vehicle attempting to gain unauthorized entry into an area

A

Intrusion Detection

84
Q

Intrusion Detection

Considerations for intrusion detection systems

A

- Should meet security needs of the facility

- Should operate in harmony with other systems

- Should not interfere with business operations

- Should be cost effective

85
Q

Intrusion Detection

Basic building blocks of an intrusion detection systems

A

Sensors

86
Q

Intrusion Detection

Detection criteria for a sensor or sensor system includes

A

- What will be detected

- What actions are expected

- Weight or speed of movement

- Probability of detection required

87
Q

Intrusion Detection

3 main characteristics of intrusion sensor performance are…

A

- Probability of detection (PD)

- Nuisance Alarm Rate (NAR)

- Vulnerability to Defeat

88
Q

Intrusion Detection

If the sensor is inappropriate for the operating environment or threat, or not installed, operated, maintained & tested properly, the output of an entire system, is severely limited, becoming a greater burden than a benefit - sensor selection must match the application & environment

A
89
Q

Intrusion Detection

Probability of Detection

A
  • Perfect is a “1” - reality is always less than “1”
  • Confidence Level (CL) is often described in conjunction with PD - unstated CL implies a 90% or better confidence level
  • PD is always conditional
  • PD also varies by the sophistication of threat
  • When high PD is required at all times & all weather conditions, use of multiple sensors
90
Q

Intrusion Detection

Probability of Detection

PD depends primarily on these facts:

A
  • Target to be detected (walk, crawl, tunneling etc…)
  • Sensor hardware design
  • Installation conditions
  • Sensitivity adjustment
  • Weather conditions
  • Condition of the equipment
91
Q

Intrusion Detection

A nuisance alarm is any alarm not caused by an intrusion

A
  • The NAR identifies the number of nuisance alarms over a given period (ideally zero, but not realistic)
  • Alarm assessment is needed to preserve manpower without assessment, detection is incomplete
  • Natural causes: vegetation, wildlife, weather conditions, etc…
  • Industrial causes: ground vibration, debris moved by wind, electromagnetic interference, etc..
92
Q

Intrusion Detection

A false alarm is a nuisance alarm generated by the equipment itself

A
  • Acceptable false alarm rate (FAR) should also be specified
  • Poor design inadequate maintenance or component failure
93
Q

Intrusion Detection

Vulnerability to Defeat

A
  • All sensors can be defeated
  • The objective is to make the system very difficult to defeat
  • Two general ways to defeat the system

Bypass: going around the detection

Spoof: passing through sensor’s normal detection zone without generating the alarm

94
Q

Intrusion Detection

Occurrence of a potential intrusion event…

A

Intrusion

95
Q

A change in the condition being monitored

A

State

96
Q

Intrusion Detection

Loss of electrical power: or failure of the sensor itself

A

Fault Event

97
Q

Intrusion Detection

Opening, shorting, or grounding of the device circuitry, the enclosure of control panels

A

Tamper

98
Q

Intrusion Detection

Five ways of classifying intrusion sensors

A
  1. Passive or active (interior & exterior)
  2. Covert or overt (interior & exterior)
  3. LOS or Terrah following (exterior only)
  4. Volumetric or line detection (point) (interior & exterior)
  5. Application (interior & exterior)
99
Q

Intrusion Detection

Two types of passive sensors

A
  1. Detect target-generated mechanical energy (walking climbing vibration)
  2. Detect target-emitted energy in a natural field of energy (heat, sound, magnetic field etc…)
100
Q

Passive Sensors

A
  • Sensors are harder to locate by aggressors because they do not emit energy
  • Safer to use in an explosive environment
  • Passive infrared, mechanical activity (walking climbing) vibration etc…
101
Q

Active Sensors

A
  • Transmit energy & detect changes to it
  • Includes transmitter & receiver (bi-static)
  • Create fewer nuisance alarms
  • Microwave, infrared, RF etc..
102
Q

Separate Transmitter & Receiver

A

Bistatic

103
Q

Transmitter & Receiver are Combined

A

Monostatic

104
Q

Detect interruption at a fixed, or volume of space

A

Volumetric Sensors

105
Q

Detect intrusion at a specific point or alarm time

A

Line or Point Sensors

106
Q

Intrusion Detection

Types of motion detectors

A

Microwave

PIR

Dual Technology

Ultrasonic

Beam Detectors

107
Q

Intrusion Detection

Video Motion Detectors (VMD)

A
  • Passive, covert, line-of-sight
  • Exterior or interior applications
  • Sufficient lighting & resolution required
  • Nuisance alarms can be plentiful - flickering lights, vegetation movement, animals, rain, camera noise
  • Analytics improve NAR
  • Digital is more sophisticated but analog is less expensive
  • Most VMDs susceptible to very slow movement
108
Q

VMD

Video Motion Detection is based on pixel changes

A
  • Changes in brightness or contrast
  • Local movement across adjacent cells
  • The speed of motion across all cells
  • Size of objects within cells
  • Global changes across most or all cells
109
Q

Wireless Sensors

A

Operate in the 300 MHz or 900 MHz bands

110
Q

Issues with wireless sensors include

A

- Collisions: multiple messages received at the same time causing none to be read

- Fading: degradation of the signal due to distance

- Interference: other signals overpowering the sensor’s signals

111
Q

Line supervision techniques

A
  • Reverse polarity
  • Sound monitoring
  • Radio class C
  • Steady direct current class B
  • Tone
  • Digital classes A & AB
112
Q

Exterior application sensors are divided into 3 categories

A

Buried Line

Fence-associated

Free Standing

113
Q

Exterior perimeter intrusion sensors

A
  • Typically used by government, nuclear, & correctional facilities
  • Ported coaxial cables
  • Fence disturbance sensors
  • Sensor fences
  • Electric field or capacitance
  • Bistatic microwave sensors
  • Exterior video motion detectors (VMDs)
114
Q

Ported Coaxial Cables

A

- “Leaky Coax”

- Active, covert, terrain-following

- Buried underground

- Respond to objects with high dielectric constant or high conductivity (humans, vehicles, etc)

- Outer jacket of cable is “ported” to allow the signal to leak out

- Range is 1.5 to 3 ft above the surface & about 3 - 6 ft wider than the cable separation

- Nuisance alarms sources include metals, water, utility lines, large quantities of salt or metals in soil

115
Q

Fence Disturbance Sensors

A
  • Passive visible terrain-following
  • Attached to fence
  • Detect motion or shock
  • One of several technologies: fiber-optic, strain-sensing vibration-sensing
  • Nuisance alarm sources are common, including wind rain/hail, nearby vibrations
  • Can be defeated by crossing over the fence w/o touching it or tunneling under
  • Fence posts should flex/move no more than .5” against a 50 lb. force at 5 ft height

- Fence fabric should flex/move no more than 2.5” against a 30 lb. force centered between posts

116
Q

Sensor Fences

A
  • Passive, visible, terrain-following
  • Sensor cables form the fence itself
  • Horizontal-stretched high tension wires at 4” or less apart
  • Includes taut-wire fences
  • Designed to detect climbing, separation of wires or cutting
  • Less susceptible to nuisance alarms - requires about 25 lbs. of force to activate the alarm
  • Can be defeated by crossing over the fence w/o touching it, or tunneling under the fence
117
Q

Electric field or capacitance sensors

A
  • Active, visible, terrain-following
  • Detects change in “capacitive-coupling” in wires isolated from the fence itself
  • Range can extend to 3.3 ft (more nuisance alarms)
  • Susceptible to lightning, rain, small animals, motion of the fence itself
  • Requires good electrical grounding
  • Less susceptible to crossing over or tunneling under fence
118
Q

Free-Standing Infrared Sensors

A
  • Active, visible, line-of-sight, free standing
  • .9 micron wavelengths - invisible to the human eye
  • Beam is transmitted through a “collimating” lens & received by a “collecting” lens
  • Multiple beams required for higher security applications (typically a 2” x 6” detection range)
  • Nuisance alarm sources include snow, fog, dust, vegetation, etc…
119
Q

Bistatic Microwave Sensors

A
  • active, visible, line-of-sight, freestanding
  • 10 GHz or 24 GHz spectrum
  • “Vector Sum”: Direct & reflected microwave energy received by the receiver
  • Susceptible to crawling or rolling under beam if the ground is not very flat or distance between antennae is more than 120 yds.

Offset Distance: zone of no detection about 10 yds. out from the transmitting antenna - requires overlapping zones of 20 yds

120
Q

Bistatic Microwave Sensors (Ctd..)

A
  • Sensor bed surface is composed of 4” of 1.5” or smaller gravel to eliminate nuisance alarms from standing water
  • The largest detection zone is midway between sensors - approximately 4 yds wide x 3 yds high
  • Nuisance alarm sources include vegetation higher than 1-2”, loose chain link fabric, heavy snow
121
Q

Exterior, perimeter intrusion sensors

Perimeter detection systems should use protection-in-dept philosophies,** relying on **two or more simultaneous lines of detection, especially in high-security facilities

A
122
Q

Exterior, perimeter intrusion sensors

Complimentary sensors may also be considered to increase the effectiveness of a sensor deployment

A
  • each sensor brings its own strengths & weaknesses to the overall security plan - complementary sensors do not have the same nuisance sources & probability of detection under each possible scenario
  • Sensors should be prioritized for assessment purposes - higher PD sensors have first priority
  • Configuration of multiple sensors should be arranged to provide overlapping coverage AND separate lines of coverage
123
Q

Exterior, perimeter intrusion sensors

Sensor combinations operate in two ways

A
  1. OR basis: Either sensors trigger the alarm high PD, higher NAR
  2. AND basis: Both sensors are required to trigger the alarm, lower PD, lower NAR
124
Q

Perimeter-in-depth philosophies

Clear zones bounded by fences on both sides are preferable for perimeter detection systems

A

No sensors should be mounted on the outside fence

125
Q

Exterior, perimeter intrusion sensors

Physical & environmental conditions affecting perimeter detection system

A

Topography (gullies, slopes, water, etc)

Vegetation (motion from wind, sources of concealment/cover)

Wildlife (large animal interference with sensors, small animal burrowing & chewing

Background noise (wind, traffic, EMI, seismic activity)

Climate & weather

Soil & pavement (soil conductivity, seismic conductivity)

126
Q

Exterior, perimeter intrusion sensors

Barriers designed to delay intrusion should be placed along the inner fenceline of a dual-fence line clear zone, to prevent tampering with the barriers without first traversing the detection zone

A
127
Q

Exterior, perimeter intrusion sensors

A clear zone “compromise” width between 10 & 15 yds. facilities reduction of nuisance alarms (wide) & high resolution for alarm assessment by cameras (narrow)

A
128
Q

Interior intrusion sensors

Interior application sensors are divided into 3 categories

A

Boundary - penetration

Interior - motion

Proximity - sensors

129
Q

Interior intrusion sensors

Two important physical conditions that affect sensor performance

A

Building or room construction

Equipment & objects that occupy the space

130
Q

Interior intrusion sensors

Electromechanical Sensors

A
  • Passive, visible, line/point sensors
  • Magnetic reed switches (doors, windows, etc..)
  • Balanced magnetic switches (BMSs) or bias magnets higher sensitivity than reed switches, less susceptible to spoofing
  • Hall effect switch detects field of magnet-no moving parts - measures charge separation & polarity - most advanced switch
  • Continuity/break wire - wires embedded or attached to surface, activated by cutting (security screens) low NAR (may use optic fibers instead)
131
Q

Interior intrusion sensors

Vibration Sensors

A
  • Passive visible or covert
  • Jiggle switches
  • Inertial switches: a metal ball mounted on metal contacts - detects vibration frequencies between 2-5 KHz
  • Piezoelectric sensors: sensing element that flexes at frequencies between 5-50 KHz
  • Fiber-optic cables detect micro-bending caused by vibration
132
Q

Glass-break Sensors

A
  • Glass-mounted, passive (vibration activated); detect > = 20 KHz vibrations
  • Glass-mounted, active; generate vibrations received by another device elsewhere on the glass (lower NAR)
  • Ceiling-mounted, passive; listen for the frequency of breaking glass; volumetric by design; not vibration activated
133
Q

Interior Motion Sensors

A
  • Monostatic microwave (common)
  • Passive infrared (PIR) (Common)
  • Dual Technology
  • Video motion detection (VMD)
134
Q

Interior intrusion sensors

Passive Infrared (PIR)

A
  • Passive to human heat approximately equal to heat from the 50-watt incandescent light bulb
  • Responds to infrared energy in the walkthrough band between 8 & 14mm
  • Minimum Resolvable Temperature: Difference in heat between target & background (can be as low as 1-degree Celsius)
135
Q

Interior intrusion sensors

Microwave

A
  • Active, visible, volumetric
  • 10 GHz frequency range: senses doppler shift of the returned frequency
  • Best positioned to sense aggressors moving towards or away from a sensor; slow-moving targets may spoof microwave sensors
  • Microwave horn, printed circuit planar, or phased array antenna
  • Various detection patterns available; concave portion of detection zone is vulnerable
136
Q

Microwave

A
  • Penetrates most glass & normal wall materials (not metal)
  • Immune to high air turbulence & temperature /changes; susceptible to “pattern drift”
  • Often used in automatic door openers; multiple microwave sensors in the same area must be on different frequencies
  • Ionized gas in fluorescent lighting can reflect microwaves & cause nuisance alarms
137
Q

Proximity Sensors

A
  • Pressure Mats
  • Capacitance Sensors
138
Q

Pressure Mats

A
  • Largely obsolete - replaced by motion detectors
  • Detected weight 5-20 lbs per sq. ft
  • Still used in security portals (man traps) to prevent tailgating - based on valid user’s weight in database
139
Q

Capacitance Sensors

A
  • Large, electrical condenser that radiates energy
  • Detects changes in capacitive coupling between antenna & the ground
  • Target touches protected object & absorbs some of the radiated energy generating on alarm

Prueba 1 (19 decks)

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