Smart Sensors and MEMS Questions and Answers

Answer: B

The key gives sensing, data acquisition, conversion and communication.

An IoT sensor node starts by sensing the physical quantity. Data acquisition then collects the sensor output and conditions it, the signal is converted into digital form (analog to digital conversion), and the digital data is finally sent to the network by the communication module. Any order that puts communication before the data exists in digital form, as in option D, cannot work, and a chain that starts with data acquisition, as in option A, has nothing to acquire yet.

The difference between B and C is only whether acquisition comes before conversion. Descriptions of the IoT sensing chain differ on this, and I could not find a source that settles it, so B stands on the University's key and on the reading that acquisition (collecting and conditioning the signal) precedes digitisation.

Answer: B

The technology associated with IoT implementation is big data analytics.

An Internet of Things system links large numbers of sensors and devices that continuously send data to the cloud. The value lies in analysing that huge, fast-flowing and varied data, which is what big data analytics provides: storage, processing and machine-learning tools that turn sensor readings into decisions and predictions.

High power drivers and cryogenics are unrelated to IoT, whose devices are typically low-power. LTCC (low temperature co-fired ceramic) is a packaging and substrate technology for RF modules, not something that characterises IoT.

Answer: C

The functional elements of MEMS are of the order of \(1 \times 10^{-6}\) m, a micrometre.

Micro-electro-mechanical systems combine tiny mechanical parts (beams, membranes, gears) with electronics on a chip. Their functional elements typically measure from about 1 to 100 micrometres, which is why they are called micro systems.

\(1 \times 10^{-3}\) m (a millimetre) is the scale of the whole device or package, and \(1 \times 10^{-9}\) m (a nanometre) is the scale of NEMS and nanotechnology. \(1 \times 10^{6}\) m is a thousand kilometres.

Answer: B

The sequence is Sensor, Data Acquisition, Communication, Cloud storage.

An IoT system starts at the physical world: sensors measure quantities such as temperature or motion. A data acquisition stage digitises and conditions those readings, a communication module (Wi-Fi, cellular, LoRa and so on) sends them over the network, and the data are stored in the cloud, where they can then be analysed.

The other options put cloud storage, data acquisition or communication first, before any sensor has produced data, which reverses the flow of information.

Answer: B

The keyed property is a large dynamic range.

Because MEMS sensors have very small moving masses, they combine high sensitivity with high resonant frequencies, and they can respond to signals over a wide range of amplitudes, from very small to large, before saturating, which is described as a large dynamic range.

Low sensitivity is the opposite of what miniaturisation gives. Their small mass gives a high, not very low, frequency response. High mechanical strength is not what follows from miniaturisation, since tiny structures are fragile and must be packaged to protect them.

Answer: A

MEMS stands for Micro-electro-mechanical systems.

MEMS are tiny devices that combine mechanical structures, such as beams, membranes and gears, with electronics on a chip, made with the microfabrication techniques of integrated circuits. Examples are the accelerometers and gyroscopes in phones, pressure sensors and inkjet print heads.

'Miniature electronic measurement systems', 'Motorised electro-mechanical systems' and 'Mechanically enhanced micro-systems' are invented expansions built from similar words.

Answer: A

Global Sensor Network is built for reducing cost and time for development.

GSN is an open-source middleware platform for sensor networks developed at EPFL. Its design goal is to make deploying and programming sensor networks quick and cheap: sensors and data streams are described declaratively in XML 'virtual sensor' files and processed with SQL-like queries, so new sensors and applications can be added without writing low-level code. Its authors present it as reducing the cost and time of developing sensor network applications.

Any middleware aims to cut development effort, so options that increase cost, increase development time, or both, run against the purpose of the platform.

Answer: C

The correct matching is (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii).

• Sensors: a device that generates an electronic signal from a physical condition, such as temperature or pressure (iii).
• Networks: the mechanism for communicating that electronic signal from place to place (iv).
• Augmented intelligence: analytical tools that improve the ability to describe, predict and act on the phenomenon the data represents (i).
• Standards: commonly accepted prescriptions for action, technical and regulatory, that let devices and systems work together (ii).

These are the layers of the Internet of Things value chain. Options A and D pair sensors with standards, and option B swaps augmented intelligence and standards, so only C matches all four.

Answer: B

The key's answer is the cloud.

IoT devices typically collect data with sensors and send it to cloud platforms, where it is stored, processed, analysed and made available to applications; commands to the devices also come from there. The cloud is therefore the place where an IoT device's data lives and is used, which is the sense of the question.

The internet and the network are the communication paths that carry the data to the cloud, not where the device's data is associated and managed. Automata are abstract machines from the theory of computation and are not how IoT devices handle data.