MyriaNed

Key takeaways

MyriaNed belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect MyriaNed to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of MyriaNed from memory before moving on to harder problems.

Reference excerpt

MyriaNed is a wireless sensor network (WSN) platform developed by DevLab. It uses an epidemic communication style based on standard radio broadcasting. This approach reflects the way humans interact, which is called gossiping. Messages are sent periodically and received by adjoining neighbours. Each message is repeated and duplicated towards all nodes that span the network; it spreads like a virus (hence the term epidemic communication). This is a very efficient and robust protocol, mainly for two reasons:

First, the nodes do not need to know who is in their neighbourhood at the time of sending a message, there is no notion of an a-priori planned Routing, data is just shared instantaneously. Second, the network is implicitly reliable since messages may follow different communication routes in parallel. The loss of a message between two nodes does not mean that the data is lost. Nodes can be added, removed or may be physically moving without the need to reconfigure the network. The GOSSIP protocol is a self-configuring network solution. The network may even be heterogeneous, where several types of nodes communicate different pieces of information with each other at the same time. This is possible due to the fact that no interpretation of the message content is required in order to be able to forward it to other nodes. Message communication is fully transparent, providing a seamless communication platform, where new functionality can be added later, without the need to change the installed base. Furthermore, MyriaNed is enabled to update the wireless sensor nodes software by means of “over the air” programming of a deployed network.

Inspiration Traditionally radio communication is organized according to the master-slave philosophy. The way two nodes communicate is point-to-point. A command is sent top-down and a confirmation is sent bottom-up between two hierarchical levels. However, in biology this is organized differently. For instance adrenaline in the human body works completely different. This message (hormone and neurotransmitter) is sent to different types of cells. Every cell knows what to do with this message (increase heart rate, constrict blood vessels, dilate air passages) and does not sent a confirmation. This is the inspiration for MyriaNed in a nutshell. Another inspiration is the basic radio broadcasting principle. A radio with an antenna is made to send and receive a message to and from every direction. Implicitly it is not optimized to perform point-to-point communication. Wires are ideally suitable for that because they always link two devices. Looking at wireless communication, it should be structured in such a way that it uses the potential of radio transmission. The third inspiration is that of human gossiping. The term is sometimes associated with spreading misinformation of trivial nature but the way information is disseminated is one of the oldest and most common in nature. Information is generated by a source and gossiped to its neighbours. They spread the message to their neighbours, thereby exponentially increasing the number of people familiar with the information. Together these three inspirations led to the development of the MyriaNed platform. There is no master-slave structure in the network rather each node is hierarchically equal. MyriaNed uses biological routing which is random and independent of the function of the node. Each node decides what to do with a message. Furthermore, it sends the message to all its neighbours thereby using the basic radio communication characteristics.

Technical overview

Data dissemination In potential the complete set of information (e.g. sensor values, control data) is available to every node in the network. By using an intelligent strategy, called shared state, this information is stored as a distributed database in the network. Nodes that are newly added to the network can utilize this shared state to instantaneously adapt and contribute to the network functionality. When it comes to caching the messages there are two scenarios. The first scenario, if a message is new to the receiving node (meaning the data was not received in previous communication rounds), the node will store the message in cache and transmit this message to its own neighbours. Secondly, if the message is old (meaning the data was already received before, i.e. through another neighbour), the message is discarded. If the cache is full, different strategies can be employed in order to make room for new messages.

Interoperability Since there is no top-down structure imposed on the network and data dissemination is transparent, the network is naturally scalable. On the communication level no identification administration is necessary and messages have a standard structure. This makes it possible that a MyriaNed network can scale far beyond the limits of currently available WSN technologies. Also different functionality can be integrated and executed on a single network.

Energy consumption In order to reduce the energy consumption of the nodes in the network duty cycling is used. This means that nodes communicate periodically, and go to standby mode in a large part of the period in order to preserve energy. In order to communicate the nodes need to wake up at the same time, therefore they have a built-in synchronization mechanism.

Radio communication During radio communication a TDMA (time-division multiple access) scheme is used to overcome collisions during broadcast communication. Current implementations run on 2.4 GHz and 868 MHz radios. The concept of MyriaNed is however not restricted to these frequencies.

Topology From the previous characteristics of MyriaNed it can be derived that it uses a true mesh topology. The advantage of such a topology is reliability, and coping with mobility, because of the redundant communication paths in the network.

Setup Setup and configuration is kept to a bare minimum because of the bottom-up approach utilized in the self-organizing network. There is no notion of a coordinator or network manager entity compared to technologies such as Zigbee or WirelessHART. This reduces the effort spent on setup and maintenance.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with MyriaNed

Start with the simplest possible case. Write down what MyriaNed claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to MyriaNed before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about MyriaNed ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of MyriaNed

In research: MyriaNed appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses MyriaNed in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: MyriaNed is common in secondary-school and first-year university syllabi. It links to neighbouring topics Network protocols, Wireless, so understanding it makes those chapters shorter.
In everyday life: Look for MyriaNed outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study MyriaNed in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what MyriaNed means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain MyriaNed out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is MyriaNed in simple terms?

MyriaNed is a wireless sensor network (WSN) platform developed by DevLab. It uses an epidemic communication style based on standard radio broadcasting.

Why does MyriaNed matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study MyriaNed?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on MyriaNed.