Baptiste Moutaud
email: moutaud.baptiste@sfr.fr

Keywords: Exploring, Treating, Enhancing forms of life, medical experimentation, neuroenhancement, neuromodulation, neuroscience

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NEUROMODULATION TECHNOLOGIES AND THE REGULATION OF FORMS OF LIFE:EXPLORING, TREATING, ENHANCING

Baptiste Moutaud

In 1986, a lucky clinical observation during a neurosurgical intervention on a patient suffering from Parkinson's disease led the French neurosurgeon Alim Louis Benabid to conceive of a new treatment for the neurodegenerative disorder. While he was electrically stimulating a cerebral area of the patient's brain with high frequency currents, he observed thesuppression of the patient's motor symptoms. A few months later, he introduced a new therapeutic intervention, deep brain stimulation (DBS) [START_REF] Benabid | Combined (thalamotomy and stimulation) stereotactic surgery of the VIM thalamic nucleus for bilateral Parkinson disease[END_REF]. The basisof this neurosurgical technology is themodulation of cerebral activity by means of electrodes implanted in patients' brains, mainly in the basal ganglia, a group of nuclei situated deep in the brain. These electrodes are connected to a battery placed in patients'chests, enabling longterm stimulation. The clinician can then alter the stimulation parameters (frequency, voltage and impulse duration) by telemetry, according to symptoms and side effects, using an external programmer.

After a decade of experiments, DBS was recognized as a reference therapy for certain forms of Parkinson's disease and replaced lesional procedures. 1 DBS is now used primarily for patients for whom chemical treatment (levodopa) has ceased to be effective on symptoms, and for whom it induces pervasive and disabling motor sides effects (dyskinesia, repetitive involuntary body movements). For this population,several clinical trials haveestablishedthat DBS efficiently improves motor symptoms (shaking and rigidity) and allows reducing medication even if, as we will see, several complications at timesappear under stimulation [START_REF] Volkmann | Deep brain stimulation for the treatment of Parkinson's disease[END_REF]).

In the early 2000s, the technology started to spread widely. 2 Furthermore, its application was experimentally extended to a wide range of neurological and psychiatric disorders, in particular dystonia (in 1999 in Canada and France), Tourette's syndrome (in 1999 in the Netherlands), obsessive-compulsive disorder (in 1999 in Belgium) and depression (in 2005 in Canada). There are now many clinical trials underway worldwide to assess the safety and efficacy of DBS in forms of these conditions that are resistant to conventional treatments (for example,pharmacology or cognitive behavioral therapies in the case of psychiatric disorders).According to Medtronic, the largest DBS device manufacturer, over 100,000 patients have undergone DBS worldwide. 3 Today, new candidate conditionsare discussed or experimented on, such as eating disorders, minimallyconscious states, addictions (alcohol, heroin, and cocaine), multiple sclerosis, bipolar disorder, schizophrenia, andAlzheimer's disease (see [START_REF] Chen | Deep brain stimulation[END_REF].

Through this expansion of applications,DBS becamea central issue not only in functional neurosurgery, neurology, and psychiatry, butalso in contemporary neuroscience, whether in terms of fundamental research or forthe purposes of care and treatment.DBShas become a priority in neuroscience research planning in many countries, largely due to neurologists' and psychiatrists'hopes that the technologymight provide solid evidence of the increasing potential of neuroscience to treat neurodegenerative diseases or psychiatric disordersin the near future. 4 Already, the success of this discovery and the expansion of uses of the intervention resulted in Benabid receiving the Lasker Award in 2014.

Among the scientific and medical challenges that have accompanied the development of neuroscience over the last 30 years, the ability to act directly on the brain to modulate its functions so as to treat illnesses or even improve individual performance stands out. Aside from neuroscientists' philosophical claims that their discipline will reveal the fundamental nature of human life, neuroscience can be defined as an aggregate of medical and scientific disciplines (such as neurobiology, cognitive sciences, neuroanatomy, psychiatry, neurology or pharmacology) sharing a common project: the study of brain anatomy and functioning in order to (1)identify and explore the neural basis of cognitive functions, thought, emotions and behaviors, and (2) discover the causes of neurological and psychiatric disorders and to elaborate therapeutics. However, considering the means available, the discourses generated, and their symbolic positioning in the public space, therapeutic innovations in neuroscience have been relatively few in number since the 1980s. In this respect, many expectations about the potential of neuroscience to develop innovative treatments have been oriented toward DBS(and more broadly neuromodulation technologies). 5 This technology and its applications have therefore received a great deal of attention from the general public,while at the same time raisingmanyethical, medical, and social issues [START_REF] Gilbert | Deep brain stimulation in the media: Over-optimistic portrayals call for a new strategy involving journalists and scientists in ethical debates[END_REF][START_REF] Racine | Currents of hope: Neurostimulation techniques in US and UK print media[END_REF].

Two lines of discourse have so far monopolized the ethical, medical and socialdiscussions of DBS. Considered together, they highlight the controversies of the field.

The first discourse appears cautious andpreventive and belongs to practitionersthemselves (neurosurgeons, psychiatrists,and neurologists). While exploring the historical development of the technology, they aim to regulate and protect the technology from excesses of hope and applications, especiallysince DBS has renewed the interest of psychiatrists and neurosurgeons for the surgical treatment of mental disorders(for instance, see Benabid's article provocatively entitled -Beware! Psychosurgery is back!,‖2006; see also Moutaud2014). 6 The second type of discourse is bioethical, and aims to arbitrate the moral issues raised by DBS. To bioethicists, DBS empiricallyunderlines what it is or is not possible-or whatmight be desirable, ethical, or moral-to do to a human being in order to provide care or to enhancecognitive and/or emotional capacities(e.g. Glannon 2014;Koivuniemi and Otto 2014).Both these approaches suggest that DBS interventions and experimentationsare a starting point for questioningneuroscienceknowledge and practice,and the acceptable forms of existence for mankind they are ultimately producing. But at the same time they contribute to generating standards of practice [START_REF] Bateman | La bioéthique comme objet sociologique[END_REF][START_REF] Tournay | De la bioéthique à l'action publique en matière de biotechnologies : la production des thérapies cellulaires[END_REF]). These discourses are therefore statements that should be examined in the light of actual practices and in relation tomedical or social interests and organizational or economic factors.

Focusing on the individual identities and the material bodies produced through DBS clinical and experimental practice,I will describe how alternative experimental uses of this technology and deviations from its original therapeutic objectives both interfere with and promote its dissemination.DBS is a compellingexample of neuroscience leaving the laboratory to inhabit bodies and modify individual experience.As an invasive biomedical technology, DBS does not merely alter representations of diseases; it reconsiders and reconfigures the links between body, individual and identity, and their co-productions [START_REF] Lock | Living and Working with the New Medical Technologies: Intersections of Inquiry[END_REF][START_REF] Hacking | Genetics, biosocialgroups and the future of identity[END_REF][START_REF] Rabinow | Artificiality and enlightenment: From sociobiology to biosociality[END_REF]. As a result, I am interested in tracingthe outlines of the various forms of life, orhuman ontologies (i.e. what kinds of human are present in concrete situations, see Piette 2012) and identities that are emerging from the use of this medical technology.I seek to apprehend empirically how the material reality of bodies and identities are produced and enacted through this biomedical innovationaccording to time and place, and how they co-exist [START_REF] Mol | The Body Multiple: Ontology in Medical Practice[END_REF].

Several authors have described how neuroscience-its practices, knowledge, technologies, therapeutics, discourses-contribute to shapea new form of existence for the individual, a new manner of seeing him/herself and of defining his/her personal identity and relational life in accordance with his/her brain and its functioning (e.g. [START_REF] Dumit | Is it me or my brain? Depression and neuroscientific facts[END_REF][START_REF] Ehrenberg | Le sujet cérébral[END_REF][START_REF] Rose | Neurochemical selves[END_REF][START_REF] Vidal | Brainhood, anthropological figure of modernity[END_REF]).If we follow Stanley [START_REF] Cavell | Declining decline. Wittgenstein as a philosopher of culture[END_REF], -forms of life‖ can be defined as the tension between a human beings' biological basis (life and its emergent forms) and the rules that govern social relations (the cultural forms of social life).Neuroscience seems tooffer new collective or individual means to negotiate the tension and the variety of modes of existence that could emergebetween these two continua. My point is therefore to clarify how human beings' new forms of existence produced through the DBS applications are discussed, regulated, or become object of controversies, and how they could hinder or accelerate the circulation and use of DBS.In this article, I therefore focusnot only on the potentialities opened for implanted patients to reconfigure their world, butalso examine the life forms this hybrid between a human being and technology allows researchers and clinicians to elaborate.

In order to do this, I will describe how neuroscientists beganto use DBS as a powerful tool to create an ‗experimental body,' a reproducible experimental human model of emotional or behavioral symptoms, so as to explore the functions of the human brain in vivo. In parallel, implanted patients influenced the care program by viewing DBS as a potential technology of self-enhancement for a wide range of attributes and personal situations. I will then explore how these alternative uses of DBS have challenged its modes of regulation and standardization and have raised new medical, scientific, and moral controversies. These concern not only ethical and methodological norms of medical and scientific practices, but also the anthropological tensions of the potential new forms of life produced by the use of this neuromodulation technology.These issues will be explored by focusing on the local deployment of DBS in a French university hospital department dedicated to clinical research in the area of neuroscience.

-WHAT DID YOU DO?‖ AN ETHNOGRAPHIC VIGNETTE There was this patient who would call Katya [the neurosurgeon] in the night to say he was in love with her. He was readmitted to the neurology department, and we altered the stimulation. And lo and behold, he didn't want to marry her anymore! Vincent, neurologist Combining fundamental research in neuroscience and medical experimentation in psychiatry and neurology, the French department team, comprising clinicians and researchers (psychiatrists, neurologists, neurosurgeons, psychologists, neuropsychologists, anatomist, brain imagers, etc.) has historically been one of the most innovative and pioneering centers in the world for DBS and its applications. 7 Members of the team started implanting Parkinson patients in 1996, and developed clinical trials for the treatment of various neurological or psychiatric conditions such as dystonia, Tourette's syndrome, OCD, addiction or depression.Between September 2004 and December 2008, I conducted ethnographic researchin this ward. I was interested in describing how this research team had operationalized the translation of DBS from neurology to psychiatry and how they legitimated it, redefining the frontiers of practice but also reconfiguring the disease definition and patients' experience (Moutaud2009). This research took place at a time when DBS research and practice was undergoing profound reconfigurations: questions were being raised concerning its extension from neurological to psychiatric indications as well as the very nature of DBS effects and follow-up required by patients as a result. Importantly, this ward initiated or actively participated in these debates, debates thatstill deeply impact on the diffusion and regulation of the technology.

In a team meeting in 2006, Vincent, one of the team's neurologists, described a consultation he had had with a patient suffering from Parkinson's disease who had been implanted. The stimulation had been adjusted and there had been good hopes that his motor symptoms would improve, as was indeed the case. However the patient had returned a few days later with his wife, who told the neurologist that once they got back home, the patient's behavior had changed. He had become restless and hyperactive, talking incessantly, interrupting her and even behaving aggressively. Vincent explained that he consequently changed the stimulation parameters, warning the patient that he might feelthe motor symptoms were a little less well controlled. He then referredthe patient to Hadrien, the team psychiatrist, for assessment. When Hadrien saw the patient, he noticed nothing in particular, and wondered why he had been referred. He reported that the patient's wife then told him that her husband had stopped his incessant talking upon leavingVincent's consulting room. After several clinical evaluations, both clinicians agreed that the initial stimulation settings led to a situation in which DBS had caused reversible symptoms of hypomania. 8 Hadrien concluded:

-and that's where the story [of their research] starts‖.

From the 2000s, neurological and psychiatricliterature reported numerous cases of behavioral or emotional side effects generated by DBS among Parkinson patients. The reports concerned a wide range of effects, such asdepression, pathological gambling, hypersexuality, episodes of rage, neurological laughter, or even a sudden passion for Johnny Cash (seeCastrioto et al. 2014, for example). These effects appeared(sometimes after only a few seconds) during or after surgery, while clinicians were adjustingthe stimulation parameters.

Symptoms of hypomania and mania were the most frequently reported. They appear close topsychopathology and are spectacular in that they involve complex, subtle behaviors. This was true of the patient mentioned above, a case that was soon followed by a second. Subsequently, Hadrien used these two cases in conferences to introduce the research in his team. In the illustrative videos he showed about the cases, the first of these two implanted Parkinson patients, aged around fifty, is seen being interviewed by a psychiatrist. He describes a party he has just organized in his home with neighbors. The evening seems to have been good fun, with ‗ball games' and ‗beach games' in his garden and swimming pool.

There are a few other anecdotes that nevertheless suggest he had been behaving strangely in the days surrounding the party and video production. He is tenseand restless. The video then shows his wife, who among other things explained that -he is very agitated, he talks all the time and is very bad-tempered‖. He even became aggressive towards her and slapped her. The following scene shows the patient, this time surprisingly calm. He says he feels ‗slow', but that the medical team -did not want to leave [him] euphoric‖.

In the second case, the scene takes placein a consultation cubicle whereHadrien and Elizabeth, one of the team's neurologists, see a patient. The video shows a woman who is agitated, talking loudly, explaining that she is ‗over-excited' and ‗yells'rather than talks.

Hadrien asks her if this is -very different from what you are usually like? Were you never like this before?‖ She answers: -I'm over-excited-why am I like that? I've never been this way in all my life. I'm fed up with being like that. Something inside me has changed, but I don't know what.‖ Elizabeth is then seen changing the parameters of the stimulation. In a new video shot a few minutes later, the woman says: -I feel less agitated. I feel better, I'm back to normal. Well, if you can call that normal...‖ In a further video shot the following morning we can seen the patient, who appears more calm, explaining that she feels -a lot less agitated, less strength in my muscles. I am calmer. I feel I'm in a normal state. Yesterday I wasn't my normal self. I'm better. What did you do?‖ Hadrien then informs the audience that in each case, the stimulation zone has merely been shifted a few millimeters in the brain structure where the electrodes were implanted.

The narrative takes on a new dimension when we learn that the team obtained consent from both patients to reproduce the effect over 24 hours for research purposes. In light of the many case reports published by other research groups, the team aimed to distinguish itself by (1) reportingthe precise localization of the electrodes in the brain and(2) correlating the results with a clinical investigation of patients in both stimulation conditions (i.e. with and without symptoms of hypomania). The case study was informed by functional brain imaging findings and motor, cognitive and behavioral assessments carried out at each consultation. The publication of the results in 2007 was an important landmark for the teamand the articlebecame a reference in this area. This research led the team to develop a general theory of brain function, at once explaining the effects of DBS on behavioral symptoms and justifying its extension to psychiatric disorders. The focus of the present paper is the entities, forms of life and forms of practice and their co-production that emerge from this research.

PRODUCING EXPERIMENTAL HUMAN BODIES, EXPLORING THE HUMAN BRAIN IN VIVO

The ethnographic vignette presented aboveillustrates the roots of the shared interest in DBS on the part of neurologists and psychiatrists, whether clinicians orresearchers, and even more so among neurosurgeons, neurophysiologists, anatomists, neuroimaging practitioners, psychologists, neuropsychologists and so forth. Indeed, in addition to being seen as a potential therapeutic technology for a whole range of conditions, DBS makes it possible to develop experimental clinical models of behavioral disorders in humans, and enables functional exploration of their neural foundations. In this sense, and independently from the issue of its efficacy, the technology is a powerful tool for functional in vivo exploration of the human brain. It feeds research on the links between motion and emotionsand between behaviors and mental states, which are central issues in neuroscience and inthe long-debated relationship between neurology and psychiatry(Moutaud2015). This use of DBS is part of the long-established neurophysiologicalculturein which electricity is enrolled to conduct functional brain exploration (see [START_REF] Borck | Through the looking glass: Past futures of brain research[END_REF][START_REF] Finger | Origins of Neuroscience: A History of Explorations into Brain Function[END_REF][START_REF] Leigh Star | Regions of the Mind[END_REF]. Several DBSresearcherswho have attempted to retrace the origins of the technologyhave indeed referred to this link (e.g. [START_REF] Butler | Historyofthetherapeuticuseofelectricityonthebrain and the development of deep brain stimulation[END_REF][START_REF] Gildenberg | Evolution of neuromodulation[END_REF][START_REF] Hariz | Deep brain stimulation between 1947 and 1987: The untold story[END_REF][START_REF] Schwalb | The history and future of deep brain stimulation[END_REF]. However these are internalist and -recurrent histories‖ (histoires récurrentes, Canguilhem 1983: 183)concerned with the technical development of DBS. They arecharacterized by their irreversibility,painting a linear trajectoryof scientific discovery and medical progress disconnected from any social, institutional or organizational contexts or interests. They do not reflect the variety of care or research practices resulting from the application of DBS to neurological or psychiatric disorders. One of the figures regularly included in these narratives is the Canadian neurosurgeon Wilder Penfield . Inclusion of this father of modern neurosurgery is indeed difficult to avoid, but as his actual implication in the history of DBS is never really specified-perhaps owing to researchers' beliefs that his role is obvious to readers-he simply serves as one of many of ‗heroic' figures in the field. 9 However, I will describe how the reference to Penfield's practices cast light on the paradigms underpinning the experimental use of DBS, its exponential development (in particular compared to less invasive or non-invasive procedures, such as vagus nerve stimulation or transcranial magnetic stimulation), and the shifts brought about in the way knowledge is produced in neuroscience.

Penfield developed asurgical methodology from a neurophysiological investigative technique using electric stimulation, which revolutionized the possibility for clinical observation and learning in operating theaters. Using this technique, any neurosurgical operation could provide scope for functional exploration of the human brain. Thus in the course of surgical interventions on patients under local anesthesia, he systematically practised a series of stimulations of the cortex. During operations, once the skull was open and the cortex accessible, Penfield subjected a given cerebral zone to electrical stimulations. An assistant remained beside the conscious patient so as to note the clinical signs triggered by these successive stimulations, and to question the patient on what s/he was experiencing. The simulated zone was then correlated with the clinical observations. This functional mapping, known as the Montreal Procedure, was performed on hundreds of individuals, yielding new maps of sensory-motor functions in the cortex, and numerous observations and discoveries on the functions of language, memory, behaviors, and emotions (see [START_REF] Eccles | Wilder Graves Penfield. 26 January 1891-5[END_REF].

This procedure was a turning point in knowledge, and above all in the means for producing knowledge, of the brain for two reasons. Firstly Penfield shifted the location of the production of knowledge: experimental neurophysiological knowledge of the brain was no longer confined to the physiology laboratory and animal experiments. It was obtained in the operating theaterexperimenting directly on human subjects. Penfield's research methods radically changed the temporality of observations by developing experimental human models of clinical signs and neurological functions. Indeed, unlike a brain lesion, electric stimulation makes the experimental model reproducible in a number of different individuals as well as repeatable in the same individual. Overall, unlike clinical and anatomopathological approaches based on particular cases of neurological deficits and disorders, Penfield's approach afforded the possibility of observing the sign, recording the subject's reported experience, and obtaining the physiopathological cause in a specifictime lapse, all in controlled and reproducible manner (Forest 2005:69).He set research issuesalongside clinical data, combining functional neurology, neurophysiology, experimentations and therapy in a single, reproducible procedure.As a result, he is credited with layingthe foundations for functional neurosurgery, and above all having systematized the methodological paradigms involved.

What is interesting here is that DBS has moved beyond thisprocedure in time and space.

It enables experimental clinical models of behavioral disorders in humans to be developed and repeated on the same individual alongside the functional exploration of the neuronal foundations of behavioral disorders, not only in the operating room but also in the consultation room. This is described above in the cases ofthe two patients under stimulation who developed symptoms of hypomania. DBS is adaptable and reversible and its technical characteristics allowit to move on from mere empirical, transitory observations on several different cases to an approach seeking to reproduce phenomena beforeassessing them. By radically altering the temporality of clinical observations in this way, DBS contributes-in patients in their therapeutic setting so long as the device remains implanted (i.e. for life)-to producingan ‗experimental body.' For Ilana [START_REF] Löwy | The experimental body[END_REF] this ‗experimental body' is an entity enabling the exploration of normal and abnormal functioning of the human body for the purpose of generating -scientifically credible knowledge‖ (Lock and Nguyen 2010:180). Here, the patient as an experimental body is a life form, an entity easier to control than the living body captured in the bustle of life. This life form is most often restricted, for ethical and methodological reasons, to laboratory animals, or to a strict setting of clinical trials. However, while Penfield opened the way to a new temporality in the operating room, DBS does away with the boundaries between treatment and research in the very act of caring for patientsin the operating theatre as well as in the consultation room.

The experimental body is enacting the neuropsychiatric and neuroscience program in practice [START_REF] Brosnan | Enacting the ‗neuro' in practice: Translational research, adhesion and the promise of porosity[END_REF].It is the subject of perusal by multiple gazes and affords a shared space and time for the convergence and translation of various interests (neurological, psychiatric, neuropsychological, neuroanatomical, and so on). Itbecomes a -trading zone‖ (Galison 1997:783-784), giving form to collaboration among viewpoints, questionings, and heterogeneous aims. It enables collective exploration of phenomena that it contributes to rendering visible. Therefore teams can establish neuropsychiatric devicesbased on DBS and on these experimental bodies. These devicesare neuropsychiatric in the sense that in the brain they directly explore links between motion and emotions, behaviors, and mental states, and enable these different functional dimensions to be manipulated experimentally. Thus the therapeutic technology has the dual function of also being a powerful tool for research and investigation, of interest to both clinicians and researchers in the termsof future applications.It offers a program for action, and -organizationalefficiency‖ (Abbott 1988:193-194; see also Löwy 1997:53): the issue of treatment efficacy is temporarily subordinated to the ability of the technology to combine interests, and create modes of organization and collaboration around its applications.

Nevertheless, this use of DBS asa technologyto explore brain functioning has not failed to raise questions among researchers in the area as to the very nature of the procedure and the status of patients used in this research. In the following section, Iset outthe main lines of these debates.

REGULATING INTERESTS AND CONTAINING ENTHUSIASMS: CARING FOR BODIES AND PATIENTS

While the multiples uses of DBShas facilitatedits rapid diffusion, its hybrid nature as a clinical/research technology has made attempts to identify the forms of practice it enables extremely complex. The challenge of this complexity is even more evident in discourses surrounding its scientific and ethical regulation. Therefore these ‗experimental bodies'are at the core of numerous debates on different structural, ethical andepistemological levels, all intersecting.

The experimental models of behavioral disordersorhazardousside effects observed on patients stimulated via DBS raise questions for researchers about the value of what these cases appear to demonstrate, and of theirappropriate place in practice. Theseexperimental modelsor hazardous side effects are often mobilized asamajorargument to initiate new therapeutic applications, or to justify experimental implantations in new cerebral target areas.

Among the most recent instances, we can cite the case of addictive behaviors (e.g. pathological gambling or hypersexuality) triggered or improved in Parkinson patients, thus orienting teams towards the treatment of addictions (see [START_REF] Hall | Is deep brain stimulation a prospective -cure‖ for addiction?[END_REF]. Researchers have also observed effects on memoryrecoveryin the case of a single patient that led to applications of DBS in Alzheimer's disease [START_REF] Hamani | Memory enhancement induced by hypothalamic/fornix deep brain stimulation[END_REF], and more generally the side effects on the emotions, contributing to the extension ofDBS to neuropsychiatric or psychiatric disorders (e.g. [START_REF] Mallet | Compulsions, Parkinson's disease and stimulation[END_REF].

Debates withinneuroscience literature have not only focused on the clinical dimensions of the phenomenato which theseexperimental models or side effects are thought to relate. These debates have also included epistemological concerns about the demonstratedvalue of these cases, often singular and very little investigatedclinically or in their biological basis, within an evidence-based regime of biomedical practice regulation.In this highly competitive area of practice, there have been calls in the scientific community to moderate enthusiasm, remarking that existing cases do not provide adequate justifications for claims of innovation [START_REF] Schlaepfer | Deep brain stimulation and the neuroethics of responsible publishing. When one is not enough[END_REF].

It is not however on this level that I focus here. For certain clinicians or researchers involved, particularly those in the center where myresearch was conducted, the problem raised by the rapid growth of experimental DBS practicedoes not reside solely in taking shortcuts or disputing the standard modes of scientific regulation of medical practice (the risk being to end up side-stepping ethical and deontological rules). The risk is rather that the technology could diffuse too rapidly in view of the clinical and technical competence and the structural means required for its deployment. 10 This would lead to these ‗experimental bodies' being integrated into care plans and environments that are problematic, which would mean, as I describe below, that much wider medical and economic issues are at stake. Indeed, while every behavioral, emotional or cognitive side effectis potentially a source of knowledge and innovation for the teams involved, it requiresclinical expertise and considerable organizational investment to provide care for the patients who undergo DBS interventions.

As in the exclamations of the second patient quoted above, individuals who have experienced hypomania side effects reported a puzzling and upsetting experience, for which they have understood neither the causes nor the mechanisms. For instance, Melville, a patient who was suffering from OCD and was implanted by the team within the context of a clinical trial, spoke to me of his experience of what the team described as an episode of hypomania: I don't know if [Elizabeth] set it too high, but on one occasion I was very agitated when they put the current back on [the stimulation]. I wasn't supposed to know [the procedure was double-blind], but I felt it because when I got home all I could do was talk, I was running round in circles, I wasn't eating, I wasn't sleeping. After that I was admitted to emergency [psychiatric ward]. I was so agitated they thought I was mad. I couldn't stop walkingaround the bed. They put me in isolation, and it was there that I noticed there were fluctuations: sometimes I was alright, and then I started going mad again. At times I was very down, I thought they had shut me away to do experiments, I was starting to go mad. (Interview, March 05, 2009).

Melville's words highlight the fact thatpatients under stimulation have no control over these side effects, nor more widely over DBS. Unlike pharmacological treatments that a patient can adapt or discontinue, the only resort for these patients is to return to the hospital to request that clinicians alter the stimulation parameters (if, as Melville, they were not hospitalized in emergency). This feeling of -loss of control‖ [START_REF] Gisquet | Cerebral implants and Parkinson's disease: A unique form of biographical disruption?[END_REF]) can be amplified by the fact that the technology is still experimental and mostly empirical concerning the adjustment of stimulation parameterssettings, as a result of both the uncertainties as to the mechanisms of action of DBS (debate is still open on the way in which DBS operates, seeKringelbach et al. 2010) and the causes of the side effects observed. The corollary of this absence ofroom for maneuver can be that the patient feels him/herself to be dependent on the technology and on the solutions offered by the healthcare team and its competency. The ideals of autonomy that underpin care plans today are thus removed from this new ‗technical' relationship. In addition, this loss of autonomy in the management of treatment leads patientsto call on practitioners more frequently. In the center studied, this has led to a saturation of the care program, and has required the structure to be adapted to cope with the influx of demands(Moutaud2011).

These questions became particularly crucial in the center where my observations were conducted when certain patients themselves expressed the desire to redirect or reorient the effects of DBS, making it a potential biotechnology of ‗self-enhancement'.

DBS AS ABIOTECHNOLOGY OF THE SELF?

DBS has become the terrain of inquiry of ethics in neuroscience, in particular focusing on the subject of changes of individual autonomy and responsibility, or on the use of DBS as a technology for the enhancement of capacities (see, e.g. [START_REF] Glannon | Stimulating brains, altering minds[END_REF][START_REF] Hildt | Electrodes in the brain: Some anthropological and ethical aspects of deep brain stimulation[END_REF][START_REF] Klaming | Did my brain implant make me do it? Questions raised by DBS regarding psychological continuity, responsibility for action and mental competence[END_REF]. In France for instance, in December 2013 the national ethics committee issued a statement on the ethical challenges of neuroenhancement where DBS,among others neuromodulation devices,was a choice because of the scope of possibilities it mightoffer individuals to improvetheir mental or cognitive capacities (Comité consultatif national d'éthique pour les sciences de la vie et de la santé 2013). However, as the French national ethics committee put it, there is in fact no actual practice of neuroenhancement by DBS, and certainly not on individual patient initiative-since as seen above,patients cannot adjust stimulation parameterson their own. Butthe committee defines enhancement narrowly as an objective improvement of psycho-cognitive capacities. By contrast, it has been suggested thatthe notion could cover anarray of situations interrogating the relation between the normal and pathological and individuals' subjective experience.

According to [START_REF] Bateman | L'amélioration humaine : Trois usages, trois enjeux[END_REF], questions concerning human enhancement relate to three conceptually distinct meanings and three levels of analysis (practical, general, individual): the enhancement of capacities, which relates to actual practices; the enhancement of human nature, which belongs to philosophical, moral and political discourse and debate, allied in particular to ‗transhumanism'; and the enhancement of the self, taking the form of subjective interpretation of practices by individuals, which is related to the anthropological question of self-fulfillment. I will explore this third levelthrough the case of implanted Parkinson patients who viewed DBS as a technology of self-enhancement for a wide range of attributes and personal situations.I describe howDBS could produce a rupture in the way stimulated patients understand the relations between their biological existence and their social lifeand how these relations subsequentlyinfluenced the care program and the DBSregulation.

Parkinson patients implanted in the research center, according to clinicians, had improved motor symptoms and were not experiencing side effects, but were nevertheless -not satisfied‖ (a neurologist). I saw one of these patients (among others) during my fieldwork while he was at a consultation with the neurologist. On that day, he entered the room and explained to the neurologist that he -was blocked‖: -It's as if the stimulator had stopped,‖ he said. The neurologist was surprised. The stimulator was functioning properly at that moment and it could not have stopped and started up again on its own. He examined the patient and then increased the stimulation radically while saying: -3.6 volts, 185 Hertz, and 90 milliseconds.‖ He explained to the patient that it had nothing to do with a -blockage‖: -It's a weakness, a generalized fatigue.‖ He remindedthe patient that at the beginning of stimulation, he was well, but afterwards, he was -never satisfied,‖ that he had said he -still had a problem of rigidity on the right side.‖ For the neurologist, the patient's complaints were linked to unrelated issues and the origin of the problem was not linked to residual motor symptoms. However, the patient was not here for the first time. I had observed almost the same situation the week before and months ago with the same patient,and the neurologist told me that he consulted on a very regular basis, ironically calling him his -favorite patient.‖ As was the case for patients who were experiencing side effects, these patientswerealso challenging the care program and its rationalization. They were in variedsocial and medical situations and expressed different reasons for dissatisfaction.These ranged from what they (or the team or their relatives) perceived as social maladaptation (for instance they had divorced or left their jobs) to complaints that the stimulation was not functioning, that they could not feel its effects, or the appearanceof new problems in their lives (such as problems with their partners, fatigue, general uneasiness,loss of energy, etc.). As patients are provided with psychopedagogical explanations for these situations (DBS is seen as causing a rupture in the patient's life and they-or their relatives-are not psychologically prepared), the central issue for the clinicians (and my analysis) lies inthat some of these patients considered DBS to be the cause of and/or the solution for their problems. They came to consultation to ask the neurologists to adjust the parameters:to be increased, for instance; wondering if it had stopped; in some cases, the spousemade the request, asking the neurologist to turn it off. Some of them even asked for the external programmer in order to be able to control the stimulation by themselves.

As I have suggested elsewhere, these implanted patients ‗naturalize' their problems, trying to use the technology and its effects as a new model of causality(Moutaud2011). DBS can then becomes a tool for self-enhancement (which could not be simply limited toenhancement of capacities), a -biotechnology of the Self‖ to return to the notion set out by Lock and Nguyen(2010:284).In contrast with the experience of the ‗experimental body', using DBS as a biotechnology of the self-via their care provider-might offer individuals the possibility of acting on their brain functionin the hopes of recovering control over their destiny, of becoming agents of their own change, with the prospect of re-inventing themselves. This enables them to objectify their experience as they aim to control their trajectory by determining the resulting lines of conduct. Their hope echoes that portrayed in Rose and Abi-Rached's analysis of neuroscience(2013) asinitiating a brain economy were the organ becomes the preferential object and target for individual and collective interventionsin order to definewhat we could or should become.This attempt to reorient the use of DBS produces a new form of life: it allows these individuals to reappraise the links between the fundamentally biological dimensions of their existence, their social identity, and their relationship to the world. But above all it enables them to act on these links. However, this form of life is then not so much the construction of a new biosocial identity (a kind of ‗biosociality', where people identified themselves to a new common biological ground in order to develop new forms of collectives or socialities, Rabinow 1996) as it isan idiom mobilized to reconfigure their worlds and arbitrate conflict-ridden situations or moral tensions arising from the misfortune that might befall individuals (Ehrenberg 2014; Moutaud2011). These patients are well known in the literature on DBS and became subjects ofsociological [START_REF] Gisquet | Cerebral implants and Parkinson's disease: A unique form of biographical disruption?[END_REF], anthropological (Moutaud2011) and ethical concerns (e. g. Gilbert 2012), and have additionally led physicians to assess patients' (and their relatives') experiencesof the therapeutics (e.g. [START_REF] Ferrara | Impact of STN-DBS on life and health satisfaction in patients with Parkinson's disease[END_REF][START_REF] Soileau | Caregiver burden in patients with Parkinson disease undergoing deep brain stimulation: An exploratory analysis[END_REF]. But above all, together with patients affected by disabling side effects (and, it has to be noted, sometimes the two situations are difficult for physicians to distinguish),theyput to the test the organization of careand its effectiveness. The team had to adapt its structure to the complexity of the clinical and personal situations generated by the technology. They reorganized modes of care provision, yielding complex organizational patterns and large numbers of different staff involved (psychiatrists, psychologists, social workers, support groups, therapeutic education, new neurological consultations, etc.), taking into account the necessary continuity of care for life-long follow-up. This increased organizational complexity hasconsequences on the modes of regulation and diffusion of this technology as a routine practice, especially given its cost (equipment and follow-up). Thus, while in France the technology has taken over from ablative procedures (lesional surgery) in psychiatry andneurology (the reimbursement of DBS for Parkinson's disease by the French national health insurance was authorized in 2005), in some other countries the question has been raised as to whether there should be a return to these previous approaches in view of complaints from patients and the problems they encounter adapting to the effects of stimulation that could prove to be too demanding on clinicians' time [START_REF] Rabins | Scientific and ethical issues related to deep brain stimulation for disorders of mood, behavior and thought[END_REF]. Due to the scarcity of centers able to provide DBS and to the cost of this technology, particularly for patients in countries where there is no universal health care, lesional surgery has proven easier to provide, despite its irreversible consequencesand side effects (see, e.g. [START_REF] Eskandar | Surgery for Parkinson disease in the United States, 1996 to 2000: Practice patterns, short-term outcomes, and hospital charges in a nationwide sample[END_REF]). 11 As a result, the problems raised by the regulation of the experimental bodiesand ‗unsatisfied' patients and the way they are produced highlight the challenges of the rationalization of care provision for patients under stimulation. For many observers, what is at stake is the actual survival of the technique.

CONCLUSION

In this article, I havecast light on the different forms of practice that structure and promote the development and circulation of a technology for the treatment of psychiatric and neurological disorders. I have described how researchers, physiciansand patients may divert the use of DBS from its therapeutic objectiveas a technology to explore the functioning of the human brain, or as a technology of self-enhancement. These diversions of DBS can coexist in time and space and contribute both to accelerating and to slowing down its circulation, stimulating interest or jeopardizing its future. Depending on situations, discourses and actors, DBS, as a powerful technology to produce knowledge and as a potential therapeutic approach for a large number of conditions, is offering a new dynamic for the neuroscience project by conflating research and the clinic, the care of patients with experimentation in a neuropsychiatric agenda.

At the same time, this neuromodulation technology appears as an empirical manifestation of the profound reconfigurations imposed by neuroscience on human beings, raising questions about the regulation of the bodies and new personal and biological identities that are produced. DBS is opening up a field of practice where we can question the frontiers of human life, and reappraise the ways we canethically manipulate living beings, transforming individuals. These new possibilities are apparent in my description of the wayimplanted patients use DBS as a new model of causality, a new mannerto redefine the links between their biological existence and their relational life. This neuro-technology provides them with a new language to assert control over their lives and produce a new form of life.

Standing at the crossroads of various clinical or research specialties, the circulation and regulation of DBS applications in neurology and psychiatry raise scientific, ethical,andsocial issues that are as wide-ranging as the plurality and entanglement of human ontologies that are shaped in its practice. DBS is too powerful and hybrid to be frozen and confined to internalist histories or imaginary narratives that ignore both the complexity of the situations produced and the different interests at stake. The question of the viability of DBS implementation as routine practice in hospital wards and national healthcare systems highlights the complexity of establishing its nature as a therapeutic technology (e.g. what it can or cannot do) and the means and goals enabling its standardization. Diffusion and circulation of neuromodulation technologies (or the lack of diffusion for some of them) correlate with ethical issues but also with institutional, industrial, financial, and structural factors that raise the question of disparities in clinical and technical skills. Tracking these moving targets still requiresprecise and systematic investigation.

functions. If the use of DBS is not the most widespread, it has a larger spectrum of therapeutic applications in neurology and psychiatry.

6. My translation. The English title provided by Benabid to the French journal is: -The return of psychosurgery.‖ 7. Although such wards are scarce and thus probably easily identified, all names have been changed to preserve anonymity, as it was agreed upon at the outset of research. 8. In psychiatry, hypomania refers to cases of elated mood leading to behaviors perceived as eccentric, and unlike the person's usual manner. The individual concerned is agitated, elated, sleeps little, talks incessantly and behaves impulsively or even aggressively. 9. See, for instance, the editorial by the psychiatrist Mayberg and the neurosurgeon Lozano (2002), two major figures in DBS, where the reference to Penfield is not explained in the text. 10. Especially in surgery, where practices are difficult to standardize [START_REF] Schlich | The art and science of surgery. Innovation and concepts of medical practice in operative fracture care, 1960s-1970s[END_REF]. The success of the procedure rests not only on surgical skills but also on the technical resources of the surgical teams (targeting technologies, brain atlases, etc.). 11. See, for instance, the recent controversy opened by a neurosurgeon who alerted the scientific community about the ethical, medical, and scientific concerns about a Mexican team which published ten cases of patients treated for ‗aggressive behavior' with lesional surgery (Lévêque, Weil and Régis 2013). While DBS was discussed as a ‗reversible' and ‗less harmful' therapeutic option, the Mexican psychiatrist in charge of these patients pointed out that families cannot afford such an expensive procedure (he evaluated the cost of DBS as approximately between US $55,000 and 70,000 versus US $500 for lesional surgery) [START_REF] Cabut | Au Mexique, l'agressivité sous le bistouri de chirurgiens[END_REF].

ACKNOWLEDGEMENTS

I am grateful to Claire Beaudevin, Stephanie Lloyd, and the three anonymous reviewers for their helpful comments on previous versions of this article.This research received funding


Damiano Nunzio Arena
email: damiano.arena@epfl.ch

Dimitris Kiritsis
email: dimitris.kiritsis@epfl.ch

Natalia Trapani
email: ntrapani@dii.unict.it

A behaviour model for risk assessment of complex systems based on HAZOP and Coloured Petri Nets

Keywords: Major Hazard Identification, HAZOP, Coloured Petri Nets

To support the knowledge of specialists during a HAZOP brainstorming session, a support system, which is able to automatically generate a preliminary HAZOP report was developed. The support system, which is based on Coloured Petri Nets (CPNs), simulates the behaviour of the system when different abnormal scenarios occur. The research demonstrates that integration of CPNs and HAZOP is very effective to obtain a smart tool for risk assessment of complex systems, improving the HAZOP analysis procedures.

Introduction

Today more than ever, safety in process industries represents an extremely important issue, which requires development and adoption of procedures helpful for carrying out a formal identification of hazard and risk assessment generated by the system complexity both in design phase and during operations. HAZOP (Hazard and Operability) analysis is a structured technique used to execute a systematic examination of process risks in major hazard plants. Although it is really time-consuming and requires significant human and economic resources, it is still most dependent tool for risk identification in chemical and petrochemical plants.

A brief literature review of these studies is discussed in order to set the state-of-theart of a potential HAZOP automation.

Literature review

A method, called HAZID, was the forerunner for the computer aided hazard identification [START_REF] Mccoy | HAZID, a computer aid for hazard identification 1[END_REF]. McCoy set out to develop a tool for hazard identification based on fault prop-agation, but did not aim that this tool would necessary emulate HAZOP. McCoy obtained a more efficient tool by the creation of a computer program for hazard identification, which is a HAZOP emulator. The general approach appears similar to HAZOPExpert [START_REF] Vaidhyanathan | HAZOPExpert: an expert system for automating HAZOP analysis[END_REF], a system based on a strong graphical interface which allows the user to easily specify piping and instrument diagrams but it is not meant to replace the HAZOP team. Its objective is to automate the routine aspects of the analysis as much as possible, thereby allowing the team to focus on more complex aspects of the analysis that cannot be automated. An evolution of HAZOPExpert for Batch processes (BHE) was first developed by Srinivasan and Venkatasubramanian, and later improved by other researchers [START_REF] Venkatasubramanian | Intelligent systems for HAZOP analysis of complex process plants[END_REF]. Thereafter, the same authors developed an automated HAZOP analysis tool for chemical processes called PHASUITE and based on Petri Nets [START_REF] Zhao | PHASUITE an automated HAZOP analysis tool for chemical processes, Part I: knowledge engineering framework[END_REF].

In the past few years, researchers have concentrated on combining HAZOP with dynamic simulation [START_REF] Wu | A novel failure model for gathering system based on Multilevel Flow modelling and HAZOP[END_REF], with Signed Directed Graph [START_REF] Isshiki | HAZOP Analysis System Compliant with Equipment Models Based on SDG[END_REF] or with techniques able to catch the structural aspects of process plants, such as Digraphs [START_REF] Boonthum | A systematic formulation for HAZOP analysis based on structural model[END_REF], D-higraphs [START_REF] Rodriguez | Automating HAZOP studies using D-higraphs[END_REF], Case-Based Reasoning, [START_REF] Cui | HASILT: An intelligent software platform for HAZOP, LOPA, SRS and SIL verification[END_REF], and Cause-Implication Diagrams [START_REF] Nemeth | Cause-Implication Diagrams for Process Systems. Their Generation, Utility and Importance[END_REF][START_REF] Toth | A structural decomposition-based diagnosis method for dynamic process systems using HAZID information[END_REF]. Most recent studies, on HAZOP methodology and its automation, was done by Lotero-Herranz and Galàn [START_REF] Lotero-Herranz | Automated HAZOP using hybrid discrete/continuous process models[END_REF]. The use of Petri Nets, as a modelling language for batch or continuous processes, has proven to be efficient and powerful, but there is a lack in literature about the use of CPNs [START_REF] Jensen | Coloured Petri Nets and CPN Tools for Modelling and Validation of Concurrent Systems[END_REF] for hazard.

HAZOP methodology

Hazard and Operability (HAZOP) study is a well-known methodology for hazard identification, useful in design phase as well as in operational phase, for analysing chemical process hazards. In order to identify causes and consequences of deviations in complex systems, a multidisciplinary team of experts applies a set of guidewords to the process sections, during structured brainstorming sessions. The analysis of problems within a HAZOP study is qualitative, but integration with quantitative risk assessment methodology is well documented [START_REF] Rausand | Risk Assessment: Theory, Methods, and Applications[END_REF]. Although this method is very liable for hazard identification in complex systems and to support risk drive engineering in manufacturing [START_REF] Trapani | Risk Driven Engineering of Prognostics and Health Management Systems in Manufacturing[END_REF], also useful for , however, the limitations of HAZOP study have been widely discussed [START_REF] Rausand | Risk Assessment: Theory, Methods, and Applications[END_REF], motivating academic and industrial researchers in seeking technological solutions for obtaining a more efficient application of this methodology.

Hence, the aim of this paper is to propose an HAZOP study carried out by analysing the propagation of several faults through different connected models that are based on Coloured Petri Nets (CPNs), taking advantage of the enhanced characteristics that will be discussed in the following section.

Coloured Petri Net language and CPN-based model

Coloured Petri Nets (CPNs) is a discrete-event graphical modelling language for constructing models of concurrent systems and analysing their properties. CPNs combine the modelling advantages of Petri Nets and compactness of the high level functional programming language Standard ML. The CPN modelling language is a general-purpose modelling language, i.e., it is not aimed at modelling a specific class of systems, but is aimed towards a very broad class of systems that can be characterized as concurrent systems.

A CPN model of a system is both state and action oriented. It describes the states of the system and the events (transitions) that can cause the system to change state. By performing simulations of the CPN model, it is possible to investigate different scenarios and explore the behaviour of the system, using customizable tokens, places, transitions and functions. The formal definition of CPNs a coloured Petri net model is a nine-tuple:

CPN {, P, T, A, N, C, G, E, IN} where Σ is a finite set of non-empty types, called colour sets, P is a finite set of places, T is a finite set of transitions, A is a finite set of arcs, N is a node function, C is a colour function, G is a guard function, E is an arc function, IN is an initialization function. Further details on CPN can be found in [START_REF] Lotero-Herranz | Automated HAZOP using hybrid discrete/continuous process models[END_REF].

The potential integration between HAZOP and CPN is studied in order to extract a behavioural model of e.g. process plant the related HAZOP analysis. The paper presents an on-going research, which shows the potential of CPN and HAZOP integration to obtain a support system for HAZOP studies. In fact, a library of component and behaviour model of typical chemical plant equipment is being developed, each component will be able to be connected with others in order to easily reproduce the P&ID (Piping & Instrumentation Diagram) of the plant, like so the system processes and information flow.

The first step for system modelling is the drawing up of a list of relevant process parameters concerning each equipment type: i.e. Flow In and Out, Level (for vessels and tanks, Pressure, Temperature, Reaction (only for reactors).Then, the mental process, through which logical connection between causes of a failure and its consequences, typical of HAZOP study, needs not only a complete knowledge of all the components failure modes but a full understanding of the so-called propagation of a failure inside and outside the component. Failure is intended as a deviation from the "normal behaviour", e.g. high level within the vessel, low flow and so on. The concept of "normal behaviour" is related to the functioning of the system, and then it is not a static condition because it evolves together with the system. Therefore, two further steps must be performed:

 The collection of all the typical causes of failure concerning each one of the modelled components;  The creation of CPN-based mechanism, which emulate the propagation of failures.

The first of these steps can be tackled by leveraging CPN colour sets. Data related to typical accidents together with their impact on the involved process variables will be collected and represented through their proper colour sets. Then, the second one is the most challenging. The automation of the so-called "failures propagation" is crucial in order to detect causes and consequences related to all the possible failures that can occur in the system. Causes and Consequences of the process variable deviations, which are related to analysed node/section/plant, constitute the main elements of a HAZOP analysis. Therefore, in this context, we define: Finally, HAZOP methodology uses a set of guidewords and parameters from which it is possible to define the above-mentioned deviations by their combination (e.g. No/Less/More Flow, Less/More Pressure, Less/More Temperature, etc.). Hence, successive issues in terms of creating models that emulate the propagation of failures through an industrial plant as well as reproducing the information flow in detail is summarized in Fig. 1.



Fig. 1. Sequence of issues in modelling process

Declarations

'CPN Tools' [19] constitute the modelling framework, which has been adopted in order to create behavioural models of industrial components such as a tank, a pump, a valve, etc. 'CPN Tools' is used for editing, simulating, state space and performance analysis of CPN models. Moreover, it supports untimed and timed hierarchical CPN models. Fig. 1 shows the types of data that are consumed within the model. In this context, coloured tokens and their properties seem particularly suitable to represent either Process variables or Causes, Consequences and Information Flow policies.

Thus, according to both the given definition of a Coloured Petri Net (Section 3) and editing framework rules, a CPN model of a component requires:

 A colour set for each kind of: ─ Process variable (VAL: Z | VL | L | N | H | VH);
─ Internal and external cause or consequence (STRING);  A set of places that may store/contain all those information modelled by colour sets.  A set of transitions, arcs and functions, which run and control the correct information flow.

"VAL" colour set represents all the "qualitative" values that can be reached by a process variable in the CPN model. It has been defined to represent the qualitative value that can be reached from any process variable, for instance, "Z" = Zero, "VL" = Very Low, L = Low, N = Normal, H = High, VH = Very High.

Components

The entire analysed section of the plant comprises of 4 elements such as, 2 valves, 1 vessel, and 1 pump. Each of the CPN models is made up of these primitive elements:

 Places, depicted as circles and necessary for storing information about the process variables;  Transitions, used for running the above mentioned information;  Arcs, connect places and transitions by driving the information flow.

Those components are consuming the above-mentioned data such as, process variable values modelled by tokens, flow policies defined by SML functions etc.

Thus, starting from previous definitions together with many available information concerning the analysed node, further issues in terms of specificity of the modelling component have been tackled during its translation into CPN model. Fig. 2 shows a snippet of the vessel model, which is made up of 5 places and 10 transitions. These are able to consume information concerning the vessel's process variables such as, temperature, pressure, level, flow-in, and flow-out, and satisfy its working policies through guards, arc and other functions.

Causes and consequences

Each grey place (see Fig. 2), which models a specific process variables, may be connected with green depicted places and transitions, which are used in order to use data related to internal and external causes (see Fig. 3). Each of those causes acts on one or more specific process variables, thus, it acts on the qualitative information modelled by a token that is stored within the relative place. During a simulation of the CPN model, the occurrence (or firing) of a green transition triggers a ripple effect, which may change the state of the involved components, according to predefined communication policies. Much of the same applies to the consequences (purple places and transitions, Fig. 4). A purple transition is enabled when specific conditions are reached by the system, which leads a component to fail in a specific way. As previously mentioned, a ripple effect is triggered when the system state changes, hence, the new state that is reached from each involved component may represent the disruption cause of a linked component. More details are given in the next section.

Information flow

Guards, inscriptions, priority levels and other customized SML functions have been defined in order to drive the information flow within the CPN model according to policies that reflect the real behaviour of the modelled system. These elements represent the model's core, in particular, guards are necessary to set bounding conditions on transitions firing, meanwhile priority levels are there to rule the execution order. This priority level definition is made according to the following typical failure evolution mechanism I→P→T (Initiation, Propagation, and Termination). In particular, only green transitions (Section 2.3) may occur at the beginning because they are the only enabled ones (Initiation of the fault). Then, the propagation of a fault is due to component's features and communication policies. This stops when a final state has been reached. Therefore, it is possible to obtain a "behaviour forecast report" from the CPN-based system by randomly firing initiating causes and tracking the system behaviour.

From CPN model to HAZOP

Once the CPN model has been developed, it is possible to extract data that will guide the HAZOP study executed by experts. Simulation of propagation of failures through the modelled system reveals interesting data about its response to those typical component failures. The term "controlled" means, it is always possible to get meaningful outputs from each firing (stop criteria have been set out not to reach meaningless states).

Therefore, CPN Tools simulation produces a ".txt" file, which exactly reports a list of all the binding elements involved during the so-called token game.

Report data should be collected even by monitoring functions or mined by external tools such as ProM [START_REF]CPN Tools homepage[END_REF] or CPNaaS (on-going project). However, data collected from simulation have been translated into a HAZOP like form through an Excel VBA macro ad-hoc designed to manage those data. The HAZOP report is still in a raw format (Fig. 5), which includes only guidewords, causes and consequences, but further developments may include important information such as automatic control systems and safeguards. The markings of a CPN represent the states of the modelled system. Once the analysed system has been modelled, the most linear procedure seems to be exploring all the possible states that system may be achieved (by performing a reachability analysis) and then analysing each path. However, this is a complex process in terms of time and computational effort. This could be at odds with proposed goals concerning time saving and process simplification for a HAZOP study. Therefore, simulating a CPN model and by reading values from the generated report, it is possible to extract all the information needed to perform a HAZOP analysis of the modelled system. For the time being the simulation has been run on a small model just to analyse both feasibility and effectiveness of the results. The under development "CPN component library" may help in expanding the model easily and quickly. Lastly, the solution obtained by translating CPN Tools report data through Excel does not represent a final product but just the quickest way to get a readable one as above mentioned. However, comparing it with an "old style" HAZOP report, the "automated" HAZOP report shows almost all the risk cases together with representing an environmentally friendly and time saving way of working. This is why the use of CPNs, in order to model the behaviour of the plant through which we can obtain a HAZOP analysis, represent a possible integration between those two methodologies, moreover, it provides a very useful and smart tool both for hazard identification process and to assess operational matters which affect production dependability and resilience.

  Internal Cause: An occurring fault within the component that causes a deviation on the component parameter (e.g., accidental event).  External Cause: The propagation of a deviation from an upstream component might be the cause of a failure within the analysed one.  Internal Consequence: Deviating process variable within a component might produce one or more internal faults.  External Consequence: An internal deviation might propagate through downstream components. It might potentially be the external cause of a downstream deviation.

Fig. 2 .

 2 Fig. 2. CPN modelvessel (D1)

Fig. 3 . 4 .

 34 Fig. 3. CPN model -Valve Causes Fig. 4. CPN Model -Pump consequences

Fig. 5 .

 5 Fig. 5. HAZOP report -"More Flow" Deviation


Anderson Luis Szejka
email: anderson.szejka@pucpr.br

Osiris Junior Canciglieri
email: osiris.canciglieri@pucpr.br

Eduardo Rocha Loures
email: eduardo.loures@pucpr.br

Hervé Panetto
email: herve.panetto@univ-lorraine.fr

Alexis Aubry
email: alexis.aubry@univ-lorraine.fr

Osiris Canciglieri Júnior

Proposal of a model-driven ontology for product development process interoperability and information sharing

Keywords: Integrated Product Development Process, Transdisciplinary Engineering, Semantic Interoperability, Formal Model, Model-Driven Ontology

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

The complexity of Product Development Process (PDP) has increased over the years to meet the customer's needs. This process requires continuous information sharing with different groups within institutional boundaries as well as across multiple organisations. Thus, the current PDP's approaches of information exchange have been based on the product master models, as detailed in [START_REF] Pahl | Engineering design: a systematic approach[END_REF] and [START_REF] Rozenfeld | Gestão de desenvolvimento de produtos: uma referência para a melhoria do processo[END_REF]. These approaches have a strict information structure, but mistakes and misinterpretation issues have been identified across different PDP phases [START_REF] Szejka | Towards a Conceptual Framework for Requirements Interoperability in Complex Systems Engineering[END_REF], [START_REF] Szejka | Requirements Interoperability Method to Support Integrated Product Development[END_REF]. This occurs because PDP has a set of transdisciplinary activities and multiple viewpoints that generate semantic obstacles without interoperability. The lack of interoperability is expensive for several globally distributed companies as discussed by [START_REF] Brunnermeier | Interoperability costs in us automotive supply chain[END_REF].

Several resourceful efforts have been fostered to integrate solutions, following product master models through the definition of common information models. This is the way that international standards have been providing basis for product information exchange, e.g. STEP PLCS (ISO 10303). Related works such as [6], [START_REF]Knowledge integration and sharing for collaborative molding product design and process development[END_REF], [START_REF] Ouertani | Traceability and management of dispersed product knowledge during design and manufacturing[END_REF], [START_REF] Liao | Semantic Annotation for Knowledge Explicitation in a Product Lifecycle Management Context: a Survey[END_REF] indicate that there is a tendency to explore the use of Semantic Web ontology languages, like the Web Ontology Language (OWL), to model the knowledge of product models. However, a significant problem is to work with multiple domains since it is necessary to find effective and technical methods for semantically map information across related domains during the PDP. It is also evident that current works do not entirely address the rules to establish an analysis of product requirements, defined by the costumer alongside the product design and manufacturing. Product requirements define the constraints and characteristics of a product and its information must be effectively shared across different phases of PDP without losing any meaning [START_REF]The Guide to the Systems Engineering Body of Knowledge (SEBoK)[END_REF].

Based on this context, this paper proposes a model-driven ontology concept to formally structured a product design and manufacturing interoperability system and the establishment of the main rules for the information and knowledge sharing to achieve the semantic interoperability in the PDP. Thus, the main contributions of this research are highlighted as: (i) improvement of the product design and manufacturing information and knowledge sharing; (ii) interoperability between multiple domains; (iii) continuous analysis of product constraints across the PDP.

Technological Background

PDP is a set of multidisciplinary activities structured to transform market opportunities, customers' needs and technological constraints in products [START_REF] Rozenfeld | Gestão de desenvolvimento de produtos: uma referência para a melhoria do processo[END_REF]. It is composed by six different phases: (i) planning; (ii) design; (iii) manufacturing; (iv) production; (v) maintenance and (vi) retirement. The process of product development is complex because information from multiple knowledge fields are simultaneously shared and exchanged through heterogeneous groups that may jointly function within institutional boundaries as well as across multiple organisations [START_REF] Hameed | Ontology reconciliation[END_REF]. Although, PDP has a holistic view of product, providing information support to different phases of product development, misinterpretation and mistakes has been identified in design and manufacturing phases [START_REF] Penciuc | Towards a PLM Interoperability for a Collaborative Design Support System[END_REF]. Furthermore, according to Rozenfeld et al. [START_REF] Rozenfeld | Gestão de desenvolvimento de produtos: uma referência para a melhoria do processo[END_REF], the activities of design and manufacturing are most costly (85% of product final cost). Therefore, in a modern PDP, design and manufacturing information and knowledge handling must be efficiently shared across different phases of PDP. This is a typical semantic interoperability problem for which the meaning associated to the captured information and knowledge must be effectively shared across systems without any loss of the meaning and intent of the information and knowledge during the exchange process [START_REF] Chungoora | A model-driven ontology approach for manufacturing system interoperability and knowledge sharing[END_REF]. The most common way to support information sharing has been to explore integrated solutions through defining common information models [6], [START_REF] Yang | A multi-agent system to facilitate component-based process modeling and design[END_REF]. In this way, improved information sharing is being investigated through constructing formal ontologies (lightweight and heavyweight ontologies) [START_REF] Noy | Translating the foundational model of anatomy into OWL[END_REF] in different domains of application such as engineering, medicine, dentistry, business, etc.

Ontology is originally defined by Gruber in 1993 [START_REF] Gruber | A translation approach to portable ontology specification[END_REF], as an "explicit specification of conceptualization". Another important definition is provided by ISO 18629:2005 [START_REF]:2005: Industrial automation systems and integration -Process Specification Language (PSL)[END_REF] that ontology is "a lexicon of specialised terminology along with some specification of the meaning of the terms in the lexicon", where lexicon is the vocabulary of a language. Ontologies can be classified according to their degree of expressiveness. Simple ontologies, for example, involving only taxonomy of concepts and basic relations, are referred to as lightweight ontologies. Ontologies with concepts and relations as a lightweight ontology enriched with axioms in the form of constraints are classified as heavyweight ontology. According to [START_REF] Gómez-Pérez | Ontological engineering: with examples from the areas of knowledge management, e-commerce and the semantic web[END_REF], axioms are used to clarify the intended meaning of the terms gathered on the ontology. However, ontologies are usually limited to the purpose of its application and it has limited reusability outside the scope of its application. Thus, ontology integration is an important task to achieve different levels of integration. Ontology integration is the process of finding commonalities between two different ontologies O and O' and deriving in a new ontology O" [START_REF] Gómez-Pérez | Ontological engineering: with examples from the areas of knowledge management, e-commerce and the semantic web[END_REF]. Based on this, three approaches for combining heterogeneous ontologies can be distinguished: (i) Ontology Inclusion; (ii) Ontology Mapping; and (iii) Ontology Merging.

Although, ontologies create semantic formalisms, a expressive problem is how to work with multiple ontologies of multiple domains to provide an effective mapping information across them [START_REF] Nagahanumaiah | Computer aided rapid tooling process selection and manufacturability evaluation for injection mold development[END_REF]. Ontology mapping has been a key direction to tackle semantic heterogeneity issues across ontologies, intending to promote semantic interoperability. Several categories of ontology mapping methods have been suggested [START_REF] Kalfoglou | Ontology mapping: the state of the art[END_REF], [START_REF] Ehrig | Ontology mapping -An integrated approach[END_REF], but there is a common consensus over the types of methods that can be applied. These types are: (i) Merging; (ii) Transformation; (iii) Alignment, and (iv) Articulation. Related works as [START_REF] Kalfoglou | Ontology mapping: the state of the art[END_REF], [START_REF] Ehrig | Ontology mapping -An integrated approach[END_REF] present significant results on using matching techniques that use the semantics of logic-based systems, which employ upper ontologies. Therefore, this work uses the structure of product development process, ontologies and ontologies mapping ontologies to extract and enrich information to support the information sharing across PDP design and manufacturing phases in a transdisciplinary environment and in accordance to the customer's needs.

IPDMS Concept

As discussed in the section 2, PDP is a set of multidisciplinary actions that gathers considerations of multiple domains and different developers team with multiple viewpoints across different phases of product development. These actions may jointly function within institutional boundaries as well as across multiple organisations [START_REF] Hameed | Ontology reconciliation[END_REF]. Thus, although PDP has different approaches to systematize the information structure, it has been identified problems of information misinterpretation and mistakes caused by non-semantic interoperability [START_REF] Penciuc | Towards a PLM Interoperability for a Collaborative Design Support System[END_REF].

Semantic interoperability is achieved when the meaning associated to the information and knowledge captured in computational form can be effectively exchanged across systems without losing any meaning and intent of the information and knowledge during the exchange process [START_REF] Chungoora | A model-driven ontology approach for manufacturing system interoperability and knowledge sharing[END_REF]. Additionally, interoperability is defined by IEEE [START_REF][END_REF] as the capacity of two or more systems to exchange information and to use the information that has been shared. Therefore, it is necessary to develop model-driven to semantic interoperability that provides balance and integrates multiple domain work and developers team with distinct viewpoints to allow the information exchange in a computational form across different phases of PDP.

In this context, Fig. 1 depicts the Interoperable Product Design and Manufacturing System (IPDMS) concept to support the information exchange in a computational form across three different phases of PDP. based on formal models and semantic reconciliation trough the semantic mapping concepts. The implication of each part of the IPDMS concept is next explained.

Foundation View and Application Domain View

The Foundation View (FV), detail B of Fig. 1, gathers and expressively represents concepts of different domains in a formal models at a relatively high level of abstraction. FV has Product Design Core, Tolerances Core, Materials Core, Manufacturing Core, etc. A Common Logic Based formalism is used to govern the way that the concepts can be formalised at the computational level.

In this way, we are using the ontologies approach to structure the FV, but we are not building ontologies. Thus, two distinct procedures to formalize the concepts based on ontological approaches are been used: (i) standards and information model in UML structure are formalize in a lightweight representation; and (ii) representations already published in ontology libraries, such as [DAML, OWL: Library, JOWL, DBpedia] are analysed and integrated to the FV. For both procedures, it is used Web Ontology Language (OWL) [START_REF]Web Ontology Language (OWL[END_REF] with axioms rules in Semantic Web Rule Language (SWRL) [START_REF]SWRL -A Semantic Web Rule Language Combining OWL and RuleML[END_REF].

The cores in FV can be individually specialized in the Application Domain View (ADV) to meet the needs of specifics Product Design and Manufacture domains. Thus, the ADV was structured in Product Model and Manufacturing Model, as illustrate in Detail C of Fig. 1. A product model may be defined as an information model that stores information related to a specific product. The same occurs with the manufacturing model that has specific information related to the method to perform the product. According to [START_REF] Chungoora | A model-driven ontology approach for manufacturing system interoperability and knowledge sharing[END_REF], product and manufacturing models have key role on PDP because they hold and share product information that are generated, used and maintained over the process of design, manufacturing, production, maintenance and disposal. Fig. 2 illustrates an example of three specialisation from the FV to the ADV to create the semantic links between concepts and a specific product.

Semantic Reconciliation View

Several transdisciplinary information are shared across different phases of PDP and need to be integrated to other models in the ADP to verify possible inconsistencies. In the event that these models need to interoperate with the intention of sharing knowledge, domain semantics need to be reconciled. Semantic Reconciliation View (SRV), detail D of Fig. 1, covers relevant applied ontology-based techniques enabling the reconciliation of domain semantics.

These techniques work segments of known ontology matching methods such as: (i) the computation of contexts for domain ontologies [START_REF] Stumme | Ontology merging for federated ontologies on the semantic web[END_REF]; (ii) ontology mapping [START_REF] Kalfoglou | Ontology mapping: the state of the art[END_REF], [START_REF] Ehrig | Ontology mapping -An integrated approach[END_REF]; and (iii) semantic alignment [START_REF] Euzenat | Ontology Matching[END_REF]. Based on this, Fig. 3 illustrates the basic concepts involved in the mapping of domain models at the SRV. The process of semantic reconciliation can be performed between pairs of models at a time, as can be encountered in almost all-current ontology mapping frameworks and methodologies [START_REF] Kalfoglou | Ontology mapping: the state of the art[END_REF]. Context Adjustment involves a first stage of contexts adjustments (namespaces in this case) of two domain models which are to be reconciled. Following this stage is a simple ontology intersection process, where both models are intact loaded on to a single specialise ontology. The last procedure in the SRV is the semantic alignment, where semantic mapping concepts are loaded into the intersected models.

Constraints View

The Constraints View (CV), detail E of Fig. 1, gathers the restrictions for developing the product based on the Product Requirements defined by the customer's needs and technological specifications. Requirement is a statement from the stakeholder's needs to define a product; system or process characteristics and it must be unambiguous, clear, unique, consistent, stand-alone and verifiable [START_REF]The Guide to the Systems Engineering Body of Knowledge (SEBoK)[END_REF]. Additionally, according to ISO/IEC 15288 [START_REF]2008: Systems and software engineering -System life cycle processes[END_REF], a requirement must be complete, coherent, unique, feasible, traceable and verifiable. Each requirement matches a single part of the future product, system or process and is grouped in an appropriate combination of textual statement views. Based on that, product requirements are used to create constraints rules to govern the way to develop the product and verify the consistency of the product design and manufacturing. Fig. 4 presents the main concepts involved to add these requirements in the IPDMS. Firstly, the main facts are manually mapped in the requirement statement and modelling in a Conceptual Graphical approach as discussed by [START_REF] Szejka | Requirements Interoperability Method to Support Integrated Product Development[END_REF]. For this modelling is used the ORM (Object Role Modelling) that is a fully communication oriented information modelling method rooted in NIAM (Natural language Information

CONSTRAINTS VIEW

Analysis Method) [START_REF] Halpin | Object-Role Modeling (ORM/NIAM)[END_REF]. According to [START_REF] Pan | Mapping Object Role Modeling into Common Logic Interchange Format[END_REF], ORM has been used in ontology engineering to model domain ontologies. Thus, the product requirements in ORM are translated to heavyweight ontologies with axiomatic rules that are submitted to the semantic reconciliation view and matched in application domain view.

Discussion of preliminary results

An experimental system has been designed and performed to validate the Interoperable Product Design and Manufacturing System (IPDMS) model-driven approach and a rotational product was chosen to explore it. The product is a polystyrene cup with thermal conservation properties, as illustrated at the left side of Fig. 5. The figure also presents a simple demonstration of the IPDMS concept, supporting the information sharing from product concept design phase to product tooling design phase.

This test case explores the material and dimension information sharing to reduce the problems with product shrinkage, which is inherent in the injection moulding process. Shrinkage occurs because the density of polymer varies from the processing temperature to the ambient temperature. According to [START_REF] Mohan | Review on the Effects of Process Parameters on Strength, Shrinkage, and Warpage of Injection Molding Plastic Component[END_REF], during the injection moulding, the variation in shrinkage creates internal stress. If the internal stress are high enough to overcome the structural integrity of the product, the product are going to wrap upon ejection from the mould or crack with external load during the extraction. Therefore, during the conception design and tooling design phases is necessary to share and transform information of the material properties and dimensions. This is a semantic obstacle because the meaning information found in the product concept must be effectively shared to product tooling design.

The IPDMS experimental demonstration is illustrates in Fig. 5. The product dimensions and geometry are extracted from the product modelled in CAD (Computer Aided Design) and structured in a XML file as illustrated on detail A of Fig. 6. The XML file has the context alignment in the Semantic Reconciliation View that identifies the main concepts and search in the foundation view the core ontologies, detail B of fig. 5, related to the information extracted from the CAD. In this test case, the ontologies specialized in the product model are material core ontology and design core ontology and the ontologies specialized in the manufacturing model are material core ontology and manufacturing core ontology. The core ontologies identified in the foundation view are specialized in the Product Model and in the Manufacturing Model of the Application View, as shown on detail C of fig. 5 and instantiated with the specific information extracted from the CAD model.

Additionally Requirements, Specifications and Technological Constraints are added to the models through the constraint view, detail D of Fig. 5, such as: Material Name, Maximum Temperature, Liquid Type, Injection Process Type, etc. These new information are semantically reconciled and intersections occur between the constraint ontology and specialized ontologies. Thus, new semantic rules are established between the both ontologies through the SWRL (Semantic Web Rule Language) and shrinkage properties are embedded in the models. Moreover, concept mapping are established between the Product Model Ontology and Manufacturing Ontology Model as well as Semantic Rules in SWRL.

According to the set of formal information and rules defined in the specialized ontologies in product and manufacturing model, a new xml file is created and is responsible for the product tooling design, as show on detail E of Fig. 5. Part of the product tooling design can be automatically performed, respecting the rules of the shrinkage process, injection process and product dimensions and tolerance. Furthermore, constraints can be added to the model, as illustrated on Detail F of Fig. 5, such as: Machine type, Injection Pressure, Cooling Time, Melt Temperature, Mould Temperature, Holding Pressure. This new XML file is converted to a CAD file and the new 3D model with the tooling design is built. This preliminary test case shows the performance of the IPDMS concept. The preliminary results show the potential of the semantic interoperability to reduce the semantic obstacles. In the test case, shrinkage issues were solved by a structured information exchange from the product design to manufacturing.

Conclusion

This paper presented the development of an Interoperable Product Design and Manufacturing System (IPDMS) concept that are able to exchange information from multiple domains across different phases of PDP in a semantic interoperability manner. The IPDMS supports the product developers, providing structured and formal information as well as transforming automatically information based on the knowledge added to the system. The IPDMS concept uses a semantically well-defined core concepts and constraints, modelling in ontologies, to instantiate the information in the application view and constraint by semantic rules. The concept architecture has four different views: (i) Foundation View, (ii) Application View, (iii) Reconciliation View and Constraint View. The Foundation View has core concepts relating to PDP, such as: material core, design core, manufacturing core, dimensional tolerance, geometry tolerance, etc. The concept core is modelled in OWL language with semantic rules in SWRL. The core concepts are specialized in Application View in Product Model and Manufacturing Model and enriched with the detailed information of the product that is being developed. More information can be added to this model by the constraints view and all information are semantically reconciled and interrelated through the semantic reconciliation view.

This concept was evaluated in a preliminary test case. The product is a polystyrene cup with thermal conservation properties. In the evaluation process the concept potential to support the information sharing between the conceptual designs and tooling design to avoid the shrinkage issues was analysed. The 3D model information was extracted and submitted to the IPDMS concept. More information was added through the constraints view. In the IPDMS, instances, context alignment, ontologies intersection and mapping concepts were established to create a product and manufacturing ontology model specialized with semantic rules to design the product tooling. The results demonstrate the potential of this concept to reduce the semantic obstacles during the information sharing across the PDP. To extend this research work it is necessary to explore more variables simultaneously and more phases of the PDP in order to analyse the potential of this concept in working and sharing information from multiple domains across different phases of PDP.

Fig. 1 .

 1 Fig. 1. Architecture of the Interoperable Product Design and Manufacturing System (IPDMS) Concept. The concept uses a semantically well-defined core of concepts and constraints to instantiate the information in the application view and link them to with the semantic rules. Thus, the architecture of IPDMS is composed by four views: (i) Foundation View; (ii) Application View; (iii) Semantic Reconciliation View; and (iv) Constraints View. The three phases of PDP are exposed on Detail A of Fig. 1: (i) Conceptual Design Phase; (ii) Tooling Design Phase; and (iii) Manufacturing Design Phase. IPDMS works

Fig. 2 .

 2 Fig. 2. Link between Foundation View and Application Domain View.

Fig. 3 .

 3 Fig. 3. Stages of Semantic Reconciliation View.

Fig. 4 .

 4 Fig. 4. Phases of Constraints View.

Fig. 5 .

 5 Fig. 5. IPDMS experimental demonstration system.

Acknowledgments. The authors would like to thank the Coordination of Improvement of Higher Education Personal -CAPES, under Science without Borders Program (Special Visiting Researcher) -Project 178/2012 and Pontifical Catholic University of Parana (PUCPR) for the financial support.