\begin{chapterabstract}
This chapter introduces the contents of the thesis and a reading guide.
Furthermore, it provides background material on \glsxtrlong{IOT}, \glsxtrlongpl{DSL}, and \glsxtrlong{TOP}; and a detailed overview of the contributions.
+ It also gives a brief introduction to two \gls{TOP} languages: \gls{ITASK} and \gls{MTASK}.
\end{chapterabstract}
-There are at least 13.4 billion computers connected to the internet at the time of writing\footnote{\url{https://transformainsights.com/research/tam/market}, accessed on: \formatdate{13}{10}{2022}}.
+There are at least 13.4 billion devices connected to the internet at the time of writing\footnote{\url{https://transformainsights.com/research/tam/market}, accessed on: \formatdate{13}{10}{2022}}.
These devices sense, act, or otherwise interact with people, other computers, and the world surrounding us.
Notwithstanding the substantial variety among these devices, they have one thing in common: they are all require software to operate.
An increasing amount of these connected devices are so-called \emph{edge devices} that operate in the \gls{IOT}.
-Typically these edge devices are small microprocessors containing sensors and actuators to interact with the physical world.
-The variety within edge devices, and the fact that they differ substantially from other types of devices, makes it complex to program \gls{IOT} systems.\todo{make sentence logical}
+Typically these edge devices are small microcontrollers containing sensors and actuators to interact with the physical world.
+Microcontrollers are integrated circuits containing a microprocessor designed for use in embedded applications.
+The edge devices come in many different types and they differ substantially from the other devices in the system.
+Consequently, programming \gls{IOT} systems is very complex and error prone.
Hence, an \gls{IOT} programmer has to program each device and their interoperation using different programming paradigms, programming languages, and abstraction levels resulting in semantic friction.
This thesis introduces research on the many aspects of orchestrating \gls{IOT} systems using \gls{TOP}.
-\Gls{TOP} is a novel programming paradigm for programming multi-tier workflow systems using a single declarative specification of the work that needs to be done.
-Using advanced compiler technologies, much of the internals and communication of multi-tier applications are automatically generated and the result of compilation is a ready-for-work application.
+\Gls{TOP} is a innovative tierless programming paradigm for programming multi-tier interactive systems using a single declarative specification of the work that needs to be done.
+Using advanced compiler technologies, much of the internals and communication of multi-tier applications is automatically generated and the result of compilation is a ready-for-work application.
Unfortunately, because the abstraction level is so high, the hardware requirements are too excessive to be suitable for the average edge device.
This is where \glspl{DSL} come into play.
The chapters are readable independently.
\Cref{prt:top} is a monograph showing \gls{MTASK}, a \gls{TOP} \gls{DSL} for the \gls{IOT}.
Hence, the chapters are best read in order.
-\Cref{prt:tvt} is a journal article in which quantitative and qualitatively compares traditional tiered \gls{IOT} programming to tierless programming.
+\Cref{prt:tvt} is a journal article in which traditional tiered \gls{IOT} programming is qualitatively and quantitatively compared to tierless programming using a real-world application.
The chapter is readable independently.
The following sections provide background material on the \gls{IOT}, \glspl{DSL}, and \gls{TOP} after which a detailed overview of the contributions is presented.
The application layer provides the \glspl{API}, data interfaces, and data storage of the \gls{IOT} system.
A cloud server or local server provides this layer in a typical home automation application.
-All layers are connected using the network layer.
-In many applications this is implemented using conventional networking techniques such as WiFi or Ethernet.
-However, networks or layers on top of it---tailored to the needs of \gls{IOT} systems---have been increasingly popular such as \gls{BLE}, LoRa, ZigBee, LTE-M, or \gls{MQTT}.
-
The perception layer---also called edge layer---collects the data and interacts with the environment.
-It consists of edge devices such as microprocessors equipped with various sensors and actuators.
+It consists of edge devices such as microcontrollers equipped with various sensors and actuators.
In home automation this layer consists of all the devices hosting the sensors and actuators such as a smart lightbulb, an actuator to open a door or a temperature and humidity sensor.
+All layers are connected using the network layer.
+In many applications this is implemented using conventional networking techniques such as WiFi or Ethernet.
+However, networks or layers on top of it---tailored to the needs of the specific interconnection between layers---have been increasingly popular.
+Examples of this are \gls{BLE}, LoRa, ZigBee, LTE-M, or \gls{MQTT} for connecting the perception layer to the application layer and techniques such as HTTP, AJAX, and WebSocket for connecting the presentation layer to the application layer.
+
Across the layers, the devices are a large heterogeneous collection of different platforms, protocols, paradigms, and programming languages often resulting in impedance problems or semantic friction between layers when programming \citep{ireland_classification_2009}.
-Even more so, perception layer itself often is a heterogeneous collections of microprocessors in itself as well, each having their own peculiarities, language of choice, and hardware interfaces.
-As the edge hardware needs to be cheap, small-scale, and energy efficient, the microprocessors used to power these devices do not have a lot of computational power, only a soup\c{c}on of memory, and little communication bandwidth.
-Typically the devices do not run a full fledged \gls{OS} but a compiled firmware that written in an imperative language.
+Even more so, perception layer itself often is a heterogeneous collections of microcontrollers in itself as well, each having their own peculiarities, language of choice, and hardware interfaces.
+As the edge hardware needs to be cheap, small-scale, and energy efficient, the microcontrollers used to power these devices do not have a lot of computational power, only a soup\c{c}on of memory, and little communication bandwidth.
+Typically the devices are unable to run a full-fledged general-purpose \gls{OS} but use compiled firmwares that are written in an imperative language.
While devices are getting a bit faster, smaller, and cheaper, they keep these properties to an extent, greatly reducing the flexibility for dynamic systems where tasks are created on the fly, executed on demand, or require parallel execution.
As program memory is mostly flash based and only lasts a couple of thousand writes before it wears out, it is not suitable for rapid reconfiguring and reprogramming.
-These problems can be mitigated by dynamically sending code to be interpreted to the microprocessor.
+These problems can be mitigated by dynamically sending code to be interpreted to the microcontroller.
With interpretation, a specialized interpreter is flashed in the program memory once that receives the program code to execute at runtime.
Interpretation always comes with an overhead, making it challenging to create them for small edge devices.
However, the hardware requirements can be reduced by embedding domain-specific data into the programming language to be interpreted, so called \glspl{DSL}.
\section{\texorpdfstring{\Glsxtrlong{TOP}}{Task-oriented programming}}\label{sec:back_top}
\Gls{TOP} is a declarative programming paradigm designed to model interactive systems \citep{plasmeijer_task-oriented_2012}.
\Citet{steenvoorden_tophat_2022} defines two instruments for \gls{TOP}: \gls{TOP} languages and \gls{TOP} engines.
-A \gls{TOP} language is a language to specify workflows.\todo{improve sentence}
-A \gls{TOP} engine executes such a specification as a ready-for-work application.
-Instead of dividing problems into layers or tiers, as is done in \gls{IOT} architectures, it deals with separation of concerns in a novel way.
+A \gls{TOP} language is the language to specify interactive systems.
+A \gls{TOP} engine is software or hardware that executes such a specification as a ready-for-work application.
+Instead of dividing problems into \gls{LSOC} it deals with separation of concerns in a novel way.
From the data types, utilising various \emph{type-parametrised} concepts, all other aspects are handled automatically (see \cref{fig:tosd}).
This approach to software development is called \gls{TOSD} \citep{wang_maintaining_2018}.
\begin{subfigure}[t]{.5\textwidth}
\centering
\includestandalone{traditional}
- \caption{Traditional layered approach.}
+ \caption{\Gls{LSOC} approach.}
\end{subfigure}%
\begin{subfigure}[t]{.5\textwidth}
\centering
\label{fig:tosd}
\end{figure}
-\todo{describe relation with \gls{IOT} architecture}
\begin{description}
\item[\Glsxtrshort{UI} (presentation layer):]
The \gls{UI} of the system is automatically generated from the representation of the type.
The \gls{UOD} from the business layer is explicitly and separately modelled by the relations that exist in the functions of the host language.
\end{description}
+There are two ways of looking at this model when also incorporating edge devices for \gls{IOT} systems.
+Firstly, edge devices can be seen as simple resources, thus accessed through the resource access layer.
+Secondly, edge devices are miniature \gls{LSOC} systems in itself as well.
+In \gls{TOSD} the same can be applied.
+The individual components in the miniature systems, the tasks, the \glspl{SDS}, are connected to the other systems.
+
\subsection{\texorpdfstring{\Gls{ITASK}}{ITask}}
-The concept of \gls{TOP} originated from the \gls{ITASK} framework, a declarative workflow language and \gls{TOP} engine for defining multi-user distributed web applications implemented as an \gls{EDSL} in the lazy pure \gls{FP} language \gls{CLEAN} \citep{plasmeijer_itasks:_2007,plasmeijer_task-oriented_2012}.
+The concept of \gls{TOP} originated from the \gls{ITASK} framework, a declarative interactive systems language and \gls{TOP} engine for defining multi-user distributed web applications implemented as an \gls{EDSL} in the lazy pure \gls{FP} language \gls{CLEAN} \citep{plasmeijer_itasks:_2007,plasmeijer_task-oriented_2012}.
From the structural properties of the data types, the entire user interface is automatically generated.
As an example, \cref{lst:enter_person,fig:enter_person} show the \gls{ITASK} code and the corresponding \gls{UI} for a simple task for entering a person.
\end{lstClean}
\subsection{\texorpdfstring{\Gls{MTASK}}{MTask}}
-This thesis uses a novel \gls{TOP} language designed for defining workflows for \gls{IOT} edge devices \citep{koopman_task-based_2018}.
+This thesis uses \gls{ITASK} in conjunction with an innovative \gls{TOP} language designed for defining interactive systems for \gls{IOT} edge devices called \gls{MTASK} \citep{koopman_task-based_2018}.
It is written in \gls{CLEAN} as a multi-view \gls{EDSL} and hence there are multiple interpretations of the language of which the byte code compiler is the most relevant for this thesis.
From the terms in the \gls{TOP} language, a very compact binary representation of the work that needs to be done is compiled.
This specification is then sent to a device that runs the \gls{MTASK} \gls{RTS}, a domain-specific \gls{TOP} engine implemented as a feather-light domain-specific \gls{OS}.
\Gls{MTASK} is seamlessly integrated with \gls{ITASK}, it allows the programmer to define all layers of an \gls{IOT} system from a single declarative specification.
-\todo[inline]{Example application here, e.g.\ blink?}
-
+\todo[inline]{Is this example useful? Add more detailed explanation with line numbers?}
+\Cref{lst:intro_blink} shows an \gls{MTASK}\slash{}\gls{ITASK} application for an interactive application where the \gls{LED} on the microcontroller blinks every user-specified interval.
+Using a \glspl{SDS} defined in \gls{ITASK}, the blinking frequency of an \gls{LED} connected to \gls{GPIO} pin 13 can be changed on the fly.
+
+\begin{lstClean}[numbers=left,caption={\Gls{MTASK}\slash{}\gls{ITASK} interactive blinking.},label={lst:intro_blink}]
+interactiveBlink :: Task Int
+interactiveBlink =
+ withShared 500 \iInterval->
+ withDevice {TCPSettings | host = ..., port = ...} \dev->
+ liftmTask (intBlink iInterval) dev
+ -|| Hint "Interval (ms)" @>> updateSharedInformation [] iInterval
+
+intBlink :: Shared sds Int -> MTask v Int | mtask, liftsds v & RWShared sds
+intBlink iInterval =
+ declarePin D13 PMOutput \d13->
+ liftsds \mInterval=iInterval
+ In fun \blink=(\st->
+ writeD d13 st
+ >>|. getSds mInterval
+ >>=. \i->delay i
+ >>|. blink (Not st))
+ In {main = blink true}
+\end{lstClean}
\subsection{Other \texorpdfstring{\glsxtrshort{TOP}}{TOP} languages}
While \gls{ITASK} conceived \gls{TOP}, it is not the only \gls{TOP} language and engine.
\section{Contributions}\label{sec:contributions}
This section provides a thorough overview of the relation to publications and the scientific contributions of the episodes and chapters.
-\subsection{\nameref{prt:dsl}}
+\subsection{\Fullref{prt:dsl}}
The \gls{MTASK} system is a heterogeneous \gls{EDSL} and during the development of it, several novel basal techniques for embedding \glspl{DSL} in \gls{FP} languages have been found.
-This first episode is a cumulative---otherwise known as paper-based---episode consisting of two papers published on novel embedding techniques.
-Both papers are readable independently.
-
-\subsubsection*{\Fullref{chp:classy_deep_embedding}}
-This chapter is based on the paper: \citeentry{lubbers_deep_2022}\todo{change in-press when published}.
+This episode is a paper based episodes on these techniques.
+\Cref{chp:classy_deep_embedding} is based on the paper \emph{Deep Embedding with Class} \citep{lubbers_deep_2022}.
While supervising \citeauthor{amazonas_cabral_de_andrade_developing_2018}'s \citeyear{amazonas_cabral_de_andrade_developing_2018} Master's thesis, focussing on an early version of \gls{MTASK}, a seed was planted for a novel deep embedding technique for \glspl{DSL} where the resulting language is extendible both in constructs and in interpretation using type classes and existential data types.
Slowly the ideas organically grew to form the technique shown in the paper.
The related work section is updated with the research found only after publication.
\Cref{sec:classy_reprise} was added after publication and contains a (yet) unpublished extension of the embedding technique for reducing the required boilerplate.
-The research from this paper and writing the paper was solely performed by me.
-
-\subsubsection*{\Fullref{chp:first-class_datatypes}}
-This chapter is based on the paper: \citeentry{lubbers_first-class_2022}\todo{change when accepted}.
+\Cref{chp:first-class_datatypes} is based on the paper \emph{First-Class Data Types in Shallow Embedded Domain-Specific Languages} \citep{lubbers_first-class_2022}.
It shows how to inherit data types from the host language in \glspl{EDSL} using metaprogramming.
It does so by providing a proof-of-concept implementation using \gls{HASKELL}'s metaprogramming system: \glsxtrlong{TH}.
Besides showing the result, the paper also serves as a gentle introduction to using \glsxtrlong{TH} and contains a thorough literature study on research that uses \glsxtrlong{TH}.
-The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer in which we discussed and refined the ideas.
+%The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer in which we discussed and refined the ideas.
\subsection{\nameref{prt:top}}
-This is a monograph compiled from several papers and revised lecture notes on \gls{MTASK}, the \gls{TOP} system used to orchestrate the \gls{IOT}.
+This is a monograph compiled from the following papers and revised lecture notes on \gls{MTASK}, the \gls{TOP} system used to orchestrate the \gls{IOT}.
It provides a gentle introduction to the \gls{MTASK} system elaborates on \gls{TOP} for the \gls{IOT}.
-\todo[inline]{outline the chapters}
\begin{itemize}
- \item \citeentry{koopman_task-based_2018}
+ \item \emph{A Task-Based \glsxtrshort{DSL} for Microcomputers} \citep{koopman_task-based_2018}.
This is the initial \gls{TOP}/\gls{MTASK} paper.
- It provides an overview of the initial \gls{MTASK} language and shows first versions of a pretty printer, an \gls{ITASK} simulation and a \gls{C} code generation view.
- \paragraph{Contribution}
- Pieter Koopman wrote it, I helped with the software and research.
- \item \citeentry{lubbers_task_2018}
+ It provides an overview of the initial \gls{TOP} \gls{MTASK} language and shows first versions of a pretty printer, an \gls{ITASK} simulation and a \gls{C} code generation view.
+ \item \emph{Task Oriented Programming for the \glsxtrlong{IOT}} \citep{lubbers_task_2018}.
This paper was an extension of my Master's thesis \citep{lubbers_task_2017}.
It shows how a simple imperative variant of \gls{MTASK} was integrated with \gls{ITASK}.
While the language was a lot different than later versions, the integration mechanism is still used in \gls{MTASK} today.
- \paragraph{Contribution}
- The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer in which we discussed and refined the ideas.
- \item \citeentry{lubbers_multitasking_2019}\footnote{%
+% \paragraph{Contribution}
+% The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer in which we discussed and refined the ideas.
+ \item \emph{Multitasking on Microcontrollers using Task Oriented Programming} \citep{lubbers_multitasking_2019}\footnote{%
This work acknowledges the support of the ERASMUS+ project ``Focusing Education on Composability, Comprehensibility and Correctness of Working Software'', no. 2017--1--SK01--KA203--035402
- }
+ }.
This paper was a short paper on the multitasking capabilities of \gls{MTASK} in contrast to traditional multitasking methods for \gls{ARDUINO}.
- \paragraph{Contribution}
- The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
- \item \citeentry{koopman_simulation_2018}\footnotemark[\value{footnote}]\todo{change when published}
+% \paragraph{Contribution}
+% The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
+ \item \emph{Simulation of a Task-Based Embedded Domain Specific Language for the Internet of Things} \citep{koopman_simulation_2018}\footnotemark[\value{footnote}].
These revised lecture notes are from a course on the \gls{MTASK} simulator was provided at the 2018 \gls{CEFP}/\gls{3COWS} winter school in Ko\v{s}ice, Slovakia.
- \paragraph{Contribution}
- Pieter Koopman wrote and taught it, I helped with the software and research.
- \item \citeentry{lubbers_writing_2019}\footnotemark[\value{footnote}]\todo{change when published}
+% \paragraph{Contribution}
+% Pieter Koopman wrote and taught it, I helped with the software and research.
+ \item \emph{Writing Internet of Things Applications with Task Oriented Programming} \citep{lubbers_writing_2019}\footnotemark[\value{footnote}].
These revised lecture notes are from a course on programming in \gls{MTASK} provided at the 2019 \gls{CEFP}/\gls{3COWS} summer school in Budapest, Hungary.
- \paragraph{Contribution}
- Pieter Koopman prepared and taught half of the lecture and supervised the practical session.
- I taught the other half of the lecture, wrote the lecture notes, made the assignments and supervised the practical session.
- \item \citeentry{lubbers_interpreting_2019}
+% \paragraph{Contribution}
+% Pieter Koopman prepared and taught half of the lecture and supervised the practical session.
+% I taught the other half of the lecture, wrote the lecture notes, made the assignments and supervised the practical session.
+ \item \emph{Interpreting Task Oriented Programs on Tiny Computers} \citep{lubbers_interpreting_2019}.
This paper shows an implementation for \gls{MTASK} for microcontrollers in the form of a compilation scheme and informal semantics description.
- \paragraph{Contribution}
- The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
- \item \citeentry{crooijmans_reducing_2022}\todo{change when published}
+% \paragraph{Contribution}
+% The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
+ \item \emph{Reducing the Power Consumption of IoT with Task-Oriented Programming} \citep{crooijmans_reducing_2022}.
This paper shows how to create a scheduler so that devices running \gls{MTASK} tasks can go to sleep more automatically.
- \paragraph{Contribution}
- The research was carried out by \citet{crooijmans_reducing_2021} during his Master's thesis.
- I did the daily supervision and helped with the research, Pieter Koopman was the formal supervisor and wrote most of the paper.
+% \paragraph{Contribution}
+% The research was carried out by \citet{crooijmans_reducing_2021} during his Master's thesis.
+% I did the daily supervision and helped with the research, Pieter Koopman was the formal supervisor and wrote most of the paper.
\item \emph{Green Computing for the Internet of Things}\footnote{
- This work acknowledges the support of the Erasmus+ project ``SusTrainable---Promoting Sustainability as a Fundamental Driver in Software Development Training and Education'', no. 2020--1--PT01--KA203--078646}\todo{change when published}
+ This work acknowledges the support of the Erasmus+ project ``SusTrainable---Promoting Sustainability as a Fundamental Driver in Software Development Training and Education'', no. 2020--1--PT01--KA203--078646}.
- \paragraph{Contribution}
- These revised lecture notes are from a course on sustainable programming using \gls{MTASK} provided at the 2022 SusTrainable summer school in Rijeka, Croatia.
- Pieter prepared and taught a quarter of the lecture and supervised the practical session.
- I prepared and taught the other three quarters of the lecture, made the assignments and supervised the practical session\todo{writing contribution}.
+% \paragraph{Contribution}
+% These revised lecture notes are from a course on sustainable programming using \gls{MTASK} provided at the 2022 SusTrainable summer school in Rijeka, Croatia.
+% Pieter prepared and taught a quarter of the lecture and supervised the practical session.
+% I prepared and taught the other three quarters of the lecture, made the assignments and supervised the practical session
\end{itemize}
+\paragraph{Contribution:}
+The original imperative predecessors the \gls{MTASK} language and their initial interpretations were developed by Pieter Koopman and Rinus Plasmeijer.
+I continued with the language; developed the byte code interpreter, the precursor to the \gls{C} code generation interpretation; the integration with \gls{ITASK}; and the \gls{RTS}.
+The paper of which I am first author are written by me.
+
\subsection{\nameref{prt:tvt}}
\Cref{prt:tvt} is based on a journal paper that quantitatively and qualitatively compares traditional \gls{IOT} architectures with \gls{IOT} systems using \gls{TOP} and contains a single chapter.
-This chapter is based on the journal paper: \citeentry{lubbers_could_2022}\todo{change when published}\footnote{This work is an extension of the conference article: \citeentry{lubbers_tiered_2020}\footnotemark{}}.
+This chapter is based on the journal paper: \emph{Could Tierless Programming Reduce IoT Development Grief?} \citep{lubbers_could_2022}\footnote{This work is an extension of the conference article: \emph{Tiered versus Tierless IoT Stacks: Comparing Smart Campus Software Architectures} \citep{lubbers_tiered_2020}\footnotemark{}}.
\footnotetext{This paper was partly funded by the Radboud-Glasgow Collaboration Fund.}
It compares programming traditional tiered architectures to tierless architectures by showing a qualitative and a quantitative four-way comparison of a smart-campus application.
-\paragraph{Contribution}
+\paragraph{Contribution:}
Writing the paper was performed by all authors.
I created the server application, the \gls{CLEAN}/\gls{ITASK}/\gls{MTASK} implementation (\glsxtrshort{CWS}) and the \gls{CLEAN}/\gls{ITASK} implementation (\glsxtrshort{CRS})
Adrian Ramsingh created the \gls{MICROPYTHON} implementation (\glsxtrshort{PWS}), the original \gls{PYTHON} implementation (\glsxtrshort{PRS}) and the server application were created by \citet{hentschel_supersensors:_2016}.
repositories / phd-thesis.git / blobdiff