X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=introduction.tex;h=62bbb9f716323ee7deaa8167908d0c907028d432;hb=76254fbf2941fa0b5a02ab3a98104cad56959218;hp=cc6b22d485f40fef8c514ba851b9d749e3e9c274;hpb=c3f505fc05f88dd9b36b433b615de6be08977601;p=msc-thesis1617.git diff --git a/introduction.tex b/introduction.tex index cc6b22d..62bbb9f 100644 --- a/introduction.tex +++ b/introduction.tex @@ -1,22 +1,136 @@ -The main goal of this thesis is to present a way to connect small \gls{IoT} -devices with high level \gls{TOP} languages. +\section{Introduction} +\Gls{IoT} technology is emerging very quickly. It offers myriads of solutions +and transforms the way we interact with technology. -\section{\acrlong{IoT}} +Initially the term was coined to describe \gls{RFID} devices and the +communication between them. However, currently the term \gls{IoT} encompasses +all small devices that communicate with each other and the world. These devices +are often equipped with sensors, \gls{GNSS}\footnote{e.g.\ the American +\gls{GPS} or the Russian \gls{GLONASS}} and actuators% +~\cite{da_xu_internet_2014}. With these new technologies information +can be tracked very accurately using very little power and bandwidth. Moreover, +\gls{IoT} technology is coming into people's homes, clothes and +healthcare~\cite{riazul_islam_internet_2015}. For example, for a few euros a +consumer ready fitness tracker watch can be bought that tracks heartbeat and +respiration levels. +The \gls{TOP} paradigm and the corresponding \gls{iTasks} implementation offer +a high abstraction level for real life workflow tasks% +~\cite{plasmeijer_itasks:_2007}. These workflow tasks can be described through +an \gls{EDSL} and modeled as \glspl{Task}. The system will generate multi-user +web app from the specification. This web service can be accessed through a +browser and is used to complete these \glspl{Task}. Familiar workflow patterns +like sequence, parallel and conditional \glspl{Task} can be modelled using +combinators. -\section{\acrlong{TOP}} +\gls{iTasks} has been proven to be useful in many fields of operation such as +incident management~~\cite{lijnse_top_2013}. Interfaces are automatically +generated for the types of data which makes rapid development possible. +\Glspl{Task} in the \gls{iTasks} system are modelled after real life workflow +tasks but the modelling is applied on a very high level. Therefore it is +difficult to connect \gls{iTasks}-\glspl{Task} to real world \glspl{Task} and +allow them to interact. A lot of the actual tasks could be performed by small +\gls{IoT} devices. Nevertheless, adding such devices to the current system is +difficult to say the least as it was not designed to cope with these devices. -\todo{Structure of the thesis} +In the current system such adapters connecting devices to \gls{iTasks} --- in +principle --- can be written as \glspl{SDS}\footnote{Similar as to resources +such as time are available in the current \gls{iTasks} implementation}. +However, this +requires a very specific adapter to be written for every device and function. +This forces a fixed logic in the device that is set at compile time. Many +small \gls{IoT} devices have limited processing power but can still contain +decision making. Oortgiese et al.\ lifted \gls{iTasks} from a single server +model to a distributed server architecture that is also runnable on small +devices such as those powered by \acrshort{ARM}~~\cite{% +oortgiese_distributed_2017}. However, this is limited to fairly high +performance devices that are equipped with high speed communication channels. +Devices in \gls{IoT} often have only \gls{LTN} communication with low bandwidth +and a very limited amount of processing power and are therefore not suitable to +run an entire \gls{iTasks} core. +\section{Problem statement} +The updates to the \gls{mTask}-system~\cite{koopman_type-safe_nodate} will +bridge this gap by introducing a new communication protocol, device application +and \glspl{Task} synchronizing the formers. The system can run on devices as +small as \gls{Arduino} microcontrollers~\cite{noauthor_arduino_nodate} and +operates via the same paradigms and patterns as regular \glspl{Task} in the +\gls{TOP} paradigm. Devices in the \gls{mTask}-system can run small imperative +programs written in an \gls{EDSL} and have access to \glspl{SDS}. \Glspl{Task} +are sent to the device at runtime, avoiding recompilation and thus write cycles +on the program memory. -\gls{TOP} is a recent new programming paradigm implemented as -\gls{iTasks}~\cite{achten_introduction_2015} in -the pure lazy functional language \gls{Clean} +\section{Document structure} +The structure of this thesis is as follows. -\todo{Main terms} -The lazy functional programming language based on graph rewriting -\gls{Clean}~\cite{brus_cleanlanguage_1987} +Chapter~\ref{chp:introduction} contains the problem statement, motivation, +related work and the structure of the document. +Chapter~\ref{chp:top} introduces the reader to the basics of \gls{TOP} and +\gls{iTasks}. +Chapter~\ref{chp:dsl} discusses the pros and cons of different embedding +methods to create \gls{EDSL}. +Chapter~\ref{chp:mtask} shows the existing \gls{mTask}-\gls{EDSL} on which is +extended upon in this dissertation. +Chapter~\ref{chp:arch} shows the architecture used for \gls{IoT}-devices that +are a part of the new \gls{mTask}-system. +Chapter~\ref{chp:mtaskcont} shows the extension added to the +\gls{mTask}-\gls{EDSL} that were needed to make the system function. +Chapter~\ref{chp:itasksint} shows the integration with \gls{iTasks} that was +built to realise the system. +Chapter~\ref{chp:conclusion} concludes by answering the research questions +and discusses future research. +Appendix~\ref{app:communication-protocol} shows the concrete protocol used for +communicating between the server and client. +Appendix~\ref{app:device-interface} shows the concrete interface for the +devices. -\todo{What am I doing} +Text written using the \CI{Teletype} font indicates code and is often +referring to a listing. \emph{Emphasized} text is used for proper nouns and +words that have a unexpected meaning. +\section{Related work} +Several types of similar research have been conducted concerning these matters. +Microcontrollers such as the \gls{Arduino} can be remotely controlled by the +\gls{Firmata}-protocol\footnote{``firmata/protocol: Documentation of the +Firmata protocol.'' (\url{https://github.com/firmata/protocol}). [Accessed: +23-May-2017].}. This protocol +is designed to expose the peripherals such as sensors to the server. This +allows very fine grained control but with the cost of excessive communication +overhead since no code is executed on the device, only the peripherals are +queried. A \gls{Haskell} implementation of the protocol has been created% +\footnote{``hArduino by LeventErkok.'' (\url{% +https://leventerkok.github.io/hArduino}). [Accessed: 23-May-2017].}. +\Gls{Clean} has a history of interpretation and there is a lot of research +happening on the intermediate language \gls{SAPL}. \Gls{SAPL} is a purely +functional intermediate language that has interpreters written in +\gls{C++}~\cite{jansen_efficient_2007} and \gls{Javascript}% +~\cite{domoszlai_implementing_2011} and \gls{Clean} and \gls{Haskell} compiler +backends~\cite{domoszlai_compiling_2012}. However, interpreting the resulting +code is still heap-heavy and therefore not directly suitable for devices with as +little as $2K$ of RAM such as the \gls{Arduino} \emph{UNO}. It might be +possible to compile the \gls{SAPL} code into efficient machine language or +\gls{C} but then the system would lose its dynamic properties since the +microcontroller then would have to be reprogrammed every time a new \gls{Task} +is sent to the device. + +\Glspl{EDSL} have often been used to generate \gls{C} code for microcontroller +environments. For starters, this work is built upon the \gls{mTask}-\gls{EDSL} +that generates \gls{C} code to run a \gls{TOP}-like system on microcontrollers% +~\cite{plasmeijer_shallow_2016}~\cite{koopman_type-safe_nodate}. +Again, this requires a reprogramming cycle every time the +\gls{Task}-specification is changed. + +Another \gls{EDSL} designed to generate low-level high-assurance programs is +called \gls{Ivory} and uses \gls{Haskell} as a host language% +~\cite{elliott_guilt_2015}. The language uses the \gls{Haskell} type-system to +make unsafe languages type safe. For example, \gls{Ivory} has been used in the +automotive industry to program parts of an autopilot% +~\cite{pike_programming_2014}~\cite{hickey_building_2014}. \Gls{Ivory}'s syntax +is deeply embedded but the type system is shallowly embedded. This requires +several \gls{Haskell} extensions that offer dependent type constructions. The +process of compiling an \gls{Ivory} program happens in stages. The embedded +code is transformed into an \gls{AST} that is sent to a backend. The +\gls{mTask} \gls{EDSL} transforms the embedded code during compile-time +directly into the backend which is often a state transformer that will execute +on runtime.