intro/intro.tex

   1 \documentclass[../thesis.tex]{subfiles}
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   3 \input{subfilepreamble}
   4
   5 \begin{document}
   6 \chapter{Prelude}%
   7 \label{chp:introduction}
   8 \begin{chapterabstract}
   9         This chapter introduces the contents of the thesis and a reading guide.
  10         Furthermore, it provides background material on \glsxtrlong{IOT}, \glsxtrlongpl{DSL}, and \glsxtrlong{TOP}; and a detailed overview of the contributions.
  11         It also gives a brief introduction to two \gls{TOP} languages: \gls{ITASK} and \gls{MTASK}.
  12 \end{chapterabstract}
  13
  14 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}}.
  15 These devices sense, act, or otherwise interact with people, other computers, and the world surrounding us.
  16 Notwithstanding the substantial variety among these devices, they have one thing in common: they are all require software to operate.
  17
  18 An increasing amount of these connected devices are so-called \emph{edge devices} that operate in the \gls{IOT}.
  19 Typically these edge devices are small microcontrollers containing sensors and actuators to interact with the physical world.
  20 Microcontrollers are integrated circuits containing a microprocessor designed for use in embedded applications.
  21 The edge devices come in many different types and they differ substantially from the other devices in the system.
  22 Consequently, programming \gls{IOT} systems is very complex and error prone.
  23 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.
  24
  25 This thesis introduces research on the many aspects of orchestrating \gls{IOT} systems using \gls{TOP}.
  26 \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.
  27 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.
  28 Unfortunately, because the abstraction level is so high, the hardware requirements are too excessive to be suitable for the average edge device.
  29
  30 This is where \glspl{DSL} come into play.
  31 \Glspl{DSL} are languages created with a specific domain in mind.
  32 Consequently, domain knowledge does not have to be expressed in the language itself but they can be built-in features, thus drastically reducing the hardware requirements even with high levels of abstraction.
  33
  34 \section{Reading guide}
  35 On Wikipedia, a musical rhapsody is defined as follows \citep{wikipedia_contributors_rhapsody_2022}:
  36 \begin{quote}\emph{%
  37         A \emph{rhapsody} in music is a one-movement work that is episodic yet integrated, free-flowing in structure, featuring a range of highly contrasted moods, colour, and tonality.}
  38 \end{quote}
  39 This thesis is structured as a pure functional rhapsody containing three episodes barded by the introduction and conclusion (\cref{chp:introduction,chp:conclusion}).
  40 \Cref{prt:dsl} is a paper-based---otherwise known as cumulative---episode providing insight in advanced \gls{DSL} embedding techniques.
  41 The chapters are readable independently.
  42 \Cref{prt:top} is a monograph showing \gls{MTASK}, a \gls{TOP} \gls{DSL} for the \gls{IOT}.
  43 Hence, the chapters are best read in order.
  44 \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.
  45 The chapter is readable independently.
  46
  47 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.
  48 Text typeset as \texttt{teletype} represents source code.
  49 Standalone source code listings are used are marked with the programming language used.
  50 For the \gls{FP} language \gls{CLEAN}, a guide tailored to \gls{HASKELL} programmers is available as in \cref{chp:clean_for_haskell_programmers}.
  51
  52 \section{Internet of things}\label{sec:back_iot}
  53 The \gls{IOT} is growing rapidly and it is changing the way people and machines interact with the world.
  54 While the term \gls{IOT} briefly gained interest around 1999 to describe the communication of \gls{RFID} devices \citep{ashton_internet_1999,ashton_that_2009}, it probably already popped up halfway the eighties in a speech by \citet{peter_t_lewis_speech_1985}:
  55
  56 \begin{quote}
  57         \emph{The \glsxtrlong{IOT}, or \glsxtrshort{IOT}, is the integration of people, processes and technology with connectable devices and sensors to enable remote monitoring, status, manipulation and evaluation of trends of such devices.}
  58 \end{quote}
  59
  60 CISCO states that the \gls{IOT} started when there where as many connected devices as there were people on the globe, i.e.\ around 2008 \citep{evans_internet_2011}.
  61 Today, \gls{IOT} is the term for a system of devices that sense the environment, act upon it and communicate with each other and the world.
  62 These connected devices are already in households all around us in the form of smart electricity meters, fridges, phones, watches, home automation, \etc.
  63
  64 When describing \gls{IOT} systems, a tiered---or layered---architecture is often used to compartmentalize the technology.
  65 The number of tiers heavily depends on the required complexity of the model but for the intents and purposes of this thesis, the four layer architecture as shown in \cref{fig:iot-layers} is used.
  66
  67 \begin{figure}[ht]
  68         \centering
  69         \includestandalone{iot-layers}
  70         \caption{A four-tier \gls{IOT} architecture.}%
  71         \label{fig:iot-layers}
  72 \end{figure}
  73
  74 To explain the tiers, an example \gls{IOT} application---home automation---is dissected accordingly.
  75 Closest to the end-user is the presentation layer, it provides the interface between the user and the \gls{IOT} system.
  76 In home automation this may be a web interface or an app used on a phone or mounted tablet to interact with the edge devices and view the sensor data.
  77
  78 The application layer provides the \glspl{API}, data interfaces, and data storage of the \gls{IOT} system.
  79 A cloud server or local server provides this layer in a typical home automation application.
  80
  81 The perception layer---also called edge layer---collects the data and interacts with the environment.
  82 It consists of edge devices such as microcontrollers equipped with various sensors and actuators.
  83 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.
  84
  85 All layers are connected using the network layer.
  86 In many applications this is implemented using conventional networking techniques such as WiFi or Ethernet.
  87 However, networks or layers on top of it---tailored to the needs of the specific interconnection between layers---have been increasingly popular.
  88 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.
  89
  90 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}.
  91 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.
  92 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.
  93 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.
  94 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.
  95 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.
  96
  97 These problems can be mitigated by dynamically sending code to be interpreted to the microcontroller.
  98 With interpretation, a specialized interpreter is flashed in the program memory once that receives the program code to execute at runtime.
  99 Interpretation always comes with an overhead, making it challenging to create them for small edge devices.
 100 However, the hardware requirements can be reduced by embedding domain-specific data into the programming language to be interpreted, so called \glspl{DSL}.
 101
 102 \section{\texorpdfstring{\Glsxtrlongpl{DSL}}{Domain-specific languages}}\label{sec:back_dsl}
 103 % General
 104 Programming languages can be divided up into two categories: \glspl{DSL}\footnote{Historically this has been called DSEL as well.} and \glspl{GPL} \citep{fowler_domain_2010}.
 105 Where \glspl{GPL} are not made with a demarcated area in mind, \glspl{DSL} are tailor-made for a specific domain.
 106 Writing idiomatic domain-specific code in an \gls{DSL} is easy but this may come at the cost of the \gls{DSL} being less expressive to an extent that it may not even be Turing complete.
 107 \Glspl{DSL} come in two main flavours: standalone and embedded (\cref{sec:standalone_embedded})\footnote{Also called external and internal respectively.} of which \glspl{EDSL} can again be classified into heterogeneous and homogeneous languages (\cref{sec:hetero_homo}).
 108 This hyponymy is shown in \cref{fig:hyponymy_of_dsls}.
 109
 110 \begin{figure}[ht]
 111         \centering
 112         \includestandalone{hyponymy_of_dsls}
 113         \caption{Hyponymy of \glspl{DSL} (adapted from \citet[\citepage{2}]{mernik_extensible_2013})}%
 114         \label{fig:hyponymy_of_dsls}
 115 \end{figure}
 116
 117 \subsection{Standalone and embedded}\label{sec:standalone_embedded}
 118 \glspl{DSL} where historically created as standalone languages, meaning all the machinery is developed solely for the language.
 119 The advantage of this approach is that the language designer is free to define the syntax and type system of the language as they wish, not being restricted by any constraint.
 120 Unfortunately it also means that they need to develop a compiler or interpreter for the language to be usable making standalone \glspl{DSL} costly to create.
 121 Examples of standalone \glspl{DSL} are regular expressions, make, yacc, XML, SQL, \etc.
 122
 123 The dichotomous approach is embedding the \gls{DSL} in a host language, i.e.\ \glspl{EDSL} \citep{hudak_modular_1998}.
 124 By defining the language as constructs in the host language, much of the machinery is inherited and the cost of creating embedded languages is very low.
 125 There is more linguistic reuse~\cite{krishnamurthi_linguistic_2001}.
 126 There are however two sides to the this coin.
 127 If the syntax of the host language is not very flexible, the syntax of the \gls{DSL} may become clumsy.
 128 Furthermore, errors shown to the programmer may be larded with host language errors, making it difficult for a non-expert of the host language to work with the \gls{DSL}.
 129 Pure \gls{FP} languages are especially suitable for hosting embedded \glspl{DSL} because they have strong and versatile type systems, minimal but flexible syntax and offer referential transparency.
 130
 131 \subsection{Heterogeneity and homogeneity}\label{sec:hetero_homo}
 132 \Citet{tratt_domain_2008} applied a notion from metaprogramming \citep{sheard_accomplishments_2001} to \glspl{EDSL} to define homogeneity and heterogeneity of \glspl{EDSL} as follows:
 133
 134 \begin{quote}
 135         \emph{
 136         A homogeneous system is one where all the components are specifically designed to work with each other, whereas in heterogeneous systems at least one of the components is largely, or completely, ignorant of the existence of the other parts of the system.
 137 }
 138 \end{quote}
 139
 140 Homogeneous \glspl{EDSL} are therefore languages that are solely defined as an extension to their host language.
 141 They often restrict features of the host language to provide a safer interface or capture an idiomatic pattern in the host language for reuse.
 142 The difference between a library and a homogeneous \glspl{EDSL} is not always clear.
 143 Examples of homogeneous \glspl{EDSL} are libraries such as ones for sets, \glspl{GUI} creation, LISP's macro system, \etc.
 144
 145 On the other hand, heterogeneous \glspl{EDSL} are languages that are not executed in the host language.
 146 For example, \citep{elliott_compiling_2003} describe the language Pan, for which the final representation in the host language is a compiler that will, when executed, generate code for a completely different target platform.
 147 In fact, \gls{ITASK} and \gls{MTASK} are both heterogeneous \glspl{EDSL} and \gls{MTASK} specifically is a compiling \gls{DSL}.
 148
 149 \section{\texorpdfstring{\Glsxtrlong{TOP}}{Task-oriented programming}}\label{sec:back_top}
 150 \Gls{TOP} is a declarative programming paradigm designed to model interactive systems \citep{plasmeijer_task-oriented_2012}.
 151 \Citet{steenvoorden_tophat_2022} defines two instruments for \gls{TOP}: \gls{TOP} languages and \gls{TOP} engines.
 152 A \gls{TOP} language is the language to specify interactive systems.
 153 A \gls{TOP} engine is software or hardware that executes such a specification as a ready-for-work application.
 154 Instead of dividing problems into \gls{LSOC} it deals with separation of concerns in a novel way.
 155 From the data types, utilising various \emph{type-parametrised} concepts, all other aspects are handled automatically (see \cref{fig:tosd}).
 156 This approach to software development is called \gls{TOSD} \citep{wang_maintaining_2018}.
 157
 158 \begin{figure}[ht]
 159         \centering
 160         \begin{subfigure}[t]{.5\textwidth}
 161                 \centering
 162                 \includestandalone{traditional}
 163                 \caption{\Gls{LSOC} approach.}
 164         \end{subfigure}%
 165         \begin{subfigure}[t]{.5\textwidth}
 166                 \centering
 167                 \includestandalone{tosd}
 168                 \caption{\Gls{TOSD} approach.}
 169         \end{subfigure}
 170         \caption{Separation of concerns in a traditional setting and in \gls{TOSD} (adapted from~\cite[\citepage{20}]{wang_maintaining_2018}).}%
 171         \label{fig:tosd}
 172 \end{figure}
 173
 174 \begin{description}
 175         \item[\Glsxtrshort{UI} (presentation layer):]
 176                 The \gls{UI} of the system is automatically generated from the representation of the type.
 177                 Even though the \gls{UI} is generated from the structure of the datatypes, in practical \gls{TOP} systems it can be tweaked afterwards to suit the specific needs of the application.
 178         \item[Tasks (business layer):]
 179                 A task is an abstract representation of a piece of work that needs to be done.
 180                 It provides an intuitive abstraction over work in the real world.
 181                 Just as with real-life tasks and workflow, tasks can be combined in various ways such as in parallel or in sequence.
 182                 Furthermore, a task is observable which means it is possible to observe a---partial---result during execution and act upon it by for example starting new tasks.
 183                 Examples of tasks are filling in a form, sending an email, reading a sensor or even doing a physical task.
 184         \item[\Glsxtrshortpl{SDS} (resource access):]
 185                 Tasks can communicate using task values but this imposes a problem in many collaboration patterns where tasks that are not necessarily related need to share data.
 186                 Tasks can also share data using \glspl{SDS}, an abstraction over any data.
 187                 An \gls{SDS} can represent typed data stored in a file, a chunk of memory, a database \etc.
 188                 \Glspl{SDS} can also represent external impure data such as the time, random numbers or sensory data.
 189                 Similar to tasks, transformation and combination of \glspl{SDS} is possible.
 190         \item[Programming language (\glsxtrshort{UOD}):]
 191                 The \gls{UOD} from the business layer is explicitly and separately modelled by the relations that exist in the functions of the host language.
 192 \end{description}
 193
 194 There are two ways of looking at this model when also incorporating edge devices for \gls{IOT} systems.
 195 Firstly, edge devices can be seen as simple resources, thus accessed through the resource access layer.
 196 Secondly, edge devices are miniature \gls{LSOC} systems in itself as well.
 197 In \gls{TOSD} the same can be applied.
 198 The individual components in the miniature systems, the tasks, the \glspl{SDS}, are connected to the other systems.
 199
 200 \subsection{\texorpdfstring{\Gls{ITASK}}{ITask}}
 201 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}.
 202 From the structural properties of the data types, the entire user interface is automatically generated.
 203
 204 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.
 205 From the data type definitions (\cref{lst:dt_fro,lst:dt_to}), using generic programming (\cref{lst:dt_derive}), the \glspl{UI} for the data types are automatically generated.
 206 Using task combinators (see \cleaninline{>>!} at \cref{lst:task_comb}), the tasks can be combined in sequence.
 207 Only when the user entered a complete value in the web editor, then the continue button enables and the result can be viewed.
 208 Special combinators (e.g.\ \cleaninline{@>>} at \cref{lst:task_ui}) are available to tweak the \gls{UI} afterwards.
 209
 210 \begin{figure}[ht]
 211         \includegraphics[width=.32\linewidth]{person0}
 212         \includegraphics[width=.32\linewidth]{person1}
 213         \includegraphics[width=.32\linewidth]{person2}
 214         \caption{The \gls{UI} for entering a person in \gls{ITASK}.}%
 215         \label{fig:enter_person}
 216 \end{figure}
 217
 218 \begin{lstClean}[numbers=left,caption={The \gls{UI} and code for entering a person in \gls{ITASK}.},label={lst:enter_person}]
 219 :: Person = { name :: String, gender :: Gender, dateOfBirth :: Date }[+\label{lst:dt_fro}+]
 220 :: Gender = Male | Female | Other String[+\label{lst:dt_to}+]
 221
 222 derive class iTask Person, Gender[+\label{lst:dt_derive}+]
 223
 224 enterPerson :: Task Person
 225 enterPerson
 226         =            Hint "Enter a person:" @>> enterInformation [][+\label{lst:task_ui}+]
 227         >>! \result->Hint "You Entered:"    @>> viewInformation  [] result[+\label{lst:task_comb}+]
 228 \end{lstClean}
 229
 230 \subsection{\texorpdfstring{\Gls{MTASK}}{MTask}}
 231 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}.
 232 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.
 233 From the terms in the \gls{TOP} language, a very compact binary representation of the work that needs to be done is compiled.
 234 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}.
 235 \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.
 236
 237 \todo[inline]{Is this example useful? Add more detailed explanation with line numbers?}
 238 \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.
 239 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.
 240
 241 \begin{lstClean}[numbers=left,caption={\Gls{MTASK}\slash{}\gls{ITASK} interactive blinking.},label={lst:intro_blink}]
 242 interactiveBlink :: Task Int
 243 interactiveBlink =
 244         withShared 500 \iInterval->
 245         withDevice {TCPSettings | host = ..., port = ...} \dev->
 246                     liftmTask (intBlink iInterval) dev
 247                 -|| Hint "Interval (ms)" @>> updateSharedInformation [] iInterval
 248
 249 intBlink :: Shared sds Int -> MTask v Int | mtask, liftsds v & RWShared sds
 250 intBlink iInterval =
 251            declarePin D13 PMOutput \d13->
 252            liftsds \mInterval=iInterval
 253         In fun \blink=(\st->
 254                      writeD d13 st
 255                 >>|. getSds mInterval
 256                 >>=. \i->delay i
 257                 >>|. blink (Not st))
 258         In {main = blink true}
 259 \end{lstClean}
 260
 261 \subsection{Other \texorpdfstring{\glsxtrshort{TOP}}{TOP} languages}
 262 While \gls{ITASK} conceived \gls{TOP}, it is not the only \gls{TOP} language and engine.
 263 Some \gls{TOP} languages and systems arose from Master's and Bachelor's thesis projects (e.g.\ \textmu{}Task \citep{piers_task-oriented_2016} and LTasks \citep{van_gemert_task_2022}) or were created to solve a practical problem (e.g.\ Toppyt \citep{lijnse_toppyt_2022} and hTask \citep{lubbers_htask_2022}).
 264 Furthermore, \gls{TOPHAT} is a fully formally specified \gls{TOP} language designed to capture the essence of \gls{TOP} formally \citep{steenvoorden_tophat_2019}.
 265 It is also possible to translate \gls{TOPHAT} code to \gls{ITASK} to piggyback on the \gls{TOP} engine it offers \citep[\citesection{G.3}]{steenvoorden_tophat_2022}.
 266
 267 \section{Contributions}\label{sec:contributions}
 268 This section provides a thorough overview of the relation to publications and the scientific contributions of the episodes and chapters.
 269
 270 \subsection{\Fullref{prt:dsl}}
 271 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.
 272 This episode is a paper based episodes on these techniques.
 273
 274 \Cref{chp:classy_deep_embedding} is based on the paper \emph{Deep Embedding with Class} \citep{lubbers_deep_2022}.
 275 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.
 276 Slowly the ideas organically grew to form the technique shown in the paper.
 277 The related work section is updated with the research found only after publication.
 278 \Cref{sec:classy_reprise} was added after publication and contains a (yet) unpublished extension of the embedding technique for reducing the required boilerplate.
 279
 280 \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}.
 281 It shows how to inherit data types from the host language in \glspl{EDSL} using metaprogramming.
 282 It does so by providing a proof-of-concept implementation using \gls{HASKELL}'s metaprogramming system: \glsxtrlong{TH}.
 283 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}.
 284 %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.
 285
 286 \subsection{\nameref{prt:top}}
 287 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}.
 288 It provides a gentle introduction to the \gls{MTASK} system elaborates on \gls{TOP} for the \gls{IOT}.
 289
 290 \begin{itemize}
 291         \item \emph{A Task-Based \glsxtrshort{DSL} for Microcomputers} \citep{koopman_task-based_2018}.
 292
 293                 This is the initial \gls{TOP}/\gls{MTASK} paper.
 294                 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.
 295         \item \emph{Task Oriented Programming for the \glsxtrlong{IOT}} \citep{lubbers_task_2018}.
 296
 297                 This paper was an extension of my Master's thesis \citep{lubbers_task_2017}.
 298                 It shows how a simple imperative variant of \gls{MTASK} was integrated with \gls{ITASK}.
 299                 While the language was a lot different than later versions, the integration mechanism is still used in \gls{MTASK} today.
 300 %               \paragraph{Contribution}
 301 %               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.
 302         \item \emph{Multitasking on Microcontrollers using Task Oriented Programming} \citep{lubbers_multitasking_2019}\footnote{%
 303                 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
 304                 }.
 305
 306                 This paper was a short paper on the multitasking capabilities of \gls{MTASK} in contrast to traditional multitasking methods for \gls{ARDUINO}.
 307 %               \paragraph{Contribution}
 308 %               The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
 309         \item \emph{Simulation of a Task-Based Embedded Domain Specific Language for the Internet of Things} \citep{koopman_simulation_2018}\footnotemark[\value{footnote}].
 310
 311                 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.
 312 %               \paragraph{Contribution}
 313 %               Pieter Koopman wrote and taught it, I helped with the software and research.
 314         \item \emph{Writing Internet of Things Applications with Task Oriented Programming} \citep{lubbers_writing_2019}\footnotemark[\value{footnote}].
 315
 316                 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.
 317 %               \paragraph{Contribution}
 318 %               Pieter Koopman prepared and taught half of the lecture and supervised the practical session.
 319 %               I taught the other half of the lecture, wrote the lecture notes, made the assignments and supervised the practical session.
 320         \item \emph{Interpreting Task Oriented Programs on Tiny Computers} \citep{lubbers_interpreting_2019}.
 321
 322                 This paper shows an implementation for \gls{MTASK} for microcontrollers in the form of a compilation scheme and informal semantics description.
 323 %               \paragraph{Contribution}
 324 %               The research in this paper and writing the paper was performed by me, though there were weekly meetings with Pieter Koopman and Rinus Plasmeijer.
 325         \item \emph{Reducing the Power Consumption of IoT with Task-Oriented Programming} \citep{crooijmans_reducing_2022}.
 326
 327                 This paper shows how to create a scheduler so that devices running \gls{MTASK} tasks can go to sleep more automatically.
 328 %               \paragraph{Contribution}
 329 %               The research was carried out by \citet{crooijmans_reducing_2021} during his Master's thesis.
 330 %               I did the daily supervision and helped with the research, Pieter Koopman was the formal supervisor and wrote most of the paper.
 331         \item \emph{Green Computing for the Internet of Things}\footnote{
 332                 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}.
 333
 334 %               \paragraph{Contribution}
 335 %               These revised lecture notes are from a course on sustainable programming using \gls{MTASK} provided at the 2022 SusTrainable summer school in Rijeka, Croatia.
 336 %               Pieter prepared and taught a quarter of the lecture and supervised the practical session.
 337 %               I prepared and taught the other three quarters of the lecture, made the assignments and supervised the practical session
 338 \end{itemize}
 339
 340 \paragraph{Contribution:}
 341 The original imperative predecessors the \gls{MTASK} language and their initial interpretations were developed by Pieter Koopman and Rinus Plasmeijer.
 342 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}.
 343 The paper of which I am first author are written by me.
 344
 345 \subsection{\nameref{prt:tvt}}
 346 \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.
 347 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{}}.
 348 \footnotetext{This paper was partly funded by the Radboud-Glasgow Collaboration Fund.}
 349
 350 It compares programming traditional tiered architectures to tierless architectures by showing a qualitative and a quantitative four-way comparison of a smart-campus application.
 351
 352 \paragraph{Contribution:}
 353 Writing the paper was performed by all authors.
 354 I created the server application, the \gls{CLEAN}/\gls{ITASK}/\gls{MTASK} implementation (\glsxtrshort{CWS}) and the \gls{CLEAN}/\gls{ITASK} implementation (\glsxtrshort{CRS})
 355 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}.
 356
 357 \input{subfilepostamble}
 358 \end{document}