operational aspects

Question 1

What is a ROC curve?

Answer 1

receiver operating characteristics curve shows either how different detectors respond compared to the same parameters, or how the same detector changes its detection ability in different environments when controlled for same detection confidence and fixed response time

closet to Y axis, the more real alarms are being seen
closer to the x axis, the more false alarms present

Question 2

what is a detection assay?

Answer 2

a way of qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity

Question 3

Describe a sampling system

Answer 3

a system that autonomously or with human interaction through a series of agreed processes, can take a sample from an environment requiring testing, use one or more sensors to try to identify threats, then provide an response to an analyst.

Question 4

What the characteristics of a biosensor ? 14 points

Answer 4

specificity
sensitivity
speed
cost
reliability
ease of manufacturing
size weight
power and consumables
ability to work in complex mixtures
low false positive rate
multianalyte detection
continuous/batch sensing
ease of operation
viability (live vs dead organisms)

Question 5

What is meant by the response time

Answer 5

time taken from a sensor reaching the limit of detection to generating an alarm

Question 6

provide a graphical representation of response time

Answer 6

Question 7

What is LOD?

Answer 7

limit of detection or detection threshold - the minimum agent concentration required for a sensor to generate an alarm.

Question 8

why is LOD important?

Answer 8

because it is the key trigger point for a system to enter an alert state

Question 9

What is a spider chart used for?

Answer 9

demonstrating the results of 12 specifications of one or more sensors

Question 10

what is a spider chart?

Answer 10

12 spoked wheel where each spoke is a measurable requirement for the sensor system. usually the further from the centre the better the system

Question 11

12 specifications of a spider chart?

Answer 11

weight
power consumption
Unit cost
reliability (MTBF)
Operating costs
MTBM
false positive rate (low dose rate)
false positive rate (high dose rate)
response time
detection confidence
sensitivity
size

Question 12

Explain deployment analysis?

Answer 12

assessment of 18 cardinal points to provide a final summary of how effective a system is, in ability to detect, but also maintain, continuously function and cost benefit

Question 13

units for weight

Answer 13

Kg though dependant on system in vivo could be mg, platform could be tonnes

Question 14

units for power consumption

Answer 14

watts

Question 15

unit for unit cost

Answer 15

£ or currency of country using device. that said, $ cost does help as an internationally understood baseline for most costings

Question 16

What is MTBF?

Answer 16

mean time between failures, or the average time between repairable failures of a technology product

Question 17

unit of MTBF

Answer 17

months, though could be context dependant to secs to years

Question 18

units for operating costs

Answer 18

£ per year

Question 19

What is MTBM

Answer 19

mean time between maintenance

Question 20

unit of MTBM

Answer 20

weeks, though could be system dependant

Question 21

unit of false positive rate

Answer 21

number per year, though could be context dependant, so covid with national screening policies could be rate per day

Question 22

response time unit

Answer 22

seconds

Question 23

unit of detection confidence

Answer 23

percentage calculated from confusion chart and ROC measurements

Question 24

unit for sensitivity

Answer 24

ACPLA - Agent Containing Particle per Litre of Air

Question 25

unit of size

Answer 25

m^3

Question 26

Is there such a thing as a one size fits all sensor?

Answer 26

no, and usually the opposite is true, should a sensor be described as a one size fits all, then it usually fails to meet the minimum requirements for any application.

Question 27

Define noise

Answer 27

is fluctuation in sensor responses due to factors that are independent of the measurement environment.

a signal to noise ration of more than 1 is important, though in some cases not necessary/ possible. in these cases more processing like conducting a Fourier transform on the data is required, but this does affect the fidelity of the output.

Question 28

define clutter

Answer 28

is the sensor response to all factors associated with the
measurement environment other than the agent.

Question 29

define signal

Answer 29

is the sensor’s response to the agent.

Question 30

18 cardinal points specifications for a bio sensor

Answer 30

specificity
selectivity
sensitivity
speed of response
stability
reproducability
repeatability
reliability
range
resolution
low false positive rate
multi analyte detection
continuous/batch sensing
ease of operation
viability
ease of manufacture
size weight power
cost

Question 31

5 S’s of cardinal points

Answer 31

specificity
selectivity
sensitivity
speed of response
stability

Question 32

4 R’s of cardinal points

Answer 32

Range
resolution
repeatability
reliability

Question 33

8 multi letters of cardinal points

Answer 33

low false positive rate
multi analyte detection
continuous/batch sensing
ease of operating
viability
ease of manufacturing
SWAP (size weight and power)
Cost

Question 34

Summary of cardinal points (13 points)

Answer 34

inital cost
operating cost
response time
limit of detection
power consumption
mission duration
consumables
maintenance
reliability
ruggedness/operationally hardened
form factor
environmental considerations