Rationale 2. Building a community-driven PID 2.1 Community-demand as a driver 2.2 Incorporated expertise and best practices as facilitators 2.3 Managing growth 2.4 Adaptable responses to community needs 2.5 Success factors 3. Issues around risks and trust regarding the emergence of new PIDs 3.1 Sustainability 3.2 Community requirements 3.3 Brand effects 3.4 Technical reliability and up-to-dateness 3.5 Indicators of trust 3.6 Issues of risks 4.

Rationale

The International Generic Sample Number (IGSN) was initially a persistent identifier for physical objects (samples).

It is used by a range of organizations as for instance System for Earth Sample Registration (SESAR), Geoscience Australia, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australian Research Data Commons (ARDC), University of Bremen's MARUM, German Research Center for Geosciences (GFZ), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) and the Korea Institute of Geoscience & Mineral Resources (KIGAM). Even though it was developed to assign PIDs only to physical samples from the Geosciences, it can be used today to assign PIDs to any physical object or collection of objects. Due to its technical and organisational openness to other use cases, IGSN became an interesting service for other communities -which is also reflected by the IGSN implementation organisation's (IGSN e.V.)1 decision to change the initial name of the identifier from International Geo Sample Number to International Generic Sample Number and rename the organisation accordingly. In late 2021 the IGSN e.V. and DataCite agreed that DataCite will operate the IGSN ID registration services and supporting technology. On the 21st of September 2022, DataCite announced that the registration of IGSNs was now technically possible. 2IGSN is considered a valuable case study first because its IDs point to physical objects instead of intellectual property or outcomes (as DOIs mostly do) or their creators. Besides, the service itself and its organisational framework were developed bottom-up in a sheer community-based effort. This effort succeeded in a way that makes it worthwhile to investigate the preconditions of this success in terms of organisational/technical growth (and how this is managed and scaled). From the beginning, the service sought technical-organisational similarity to a best practice -a strategy that made it easy to drop its own handle systems in favour of a partnership with an established PID provider as DataCite.

Given that this also means that IGSN identifiers would become DataCite DOIs, and any DataCite member will be able to register identifiers for samples as IGSNs through DataCite, the IGSN Case Study may also help to illustrate how the PID system itself evolves by bringing up new PIDs through community services -especially where the initial needs are regarded as too marginal to be satisfied by established service providers not serving a community. IGSN made systematic use of brand effects (or produced them through cooperation), and made systematic use of funding to safeguard its growth and clearly identified the need for professionalisation. It also benefited from experience (organisational and technical) gained by one of the main actors in the implementation and operation of the service, which had a far-reaching impact on the chosen technology and organisational form.

2 Building a community-driven PID

Community-demand as a driver

The need to build a dedicated PID for samples or physical objects arose from the lack of one that could be used across organisations: "Organisations such as museums, geological surveys, and networked research programmes like the International Ocean Discovery Program (IODP) have systems in place for the unique identification of their samples. These systems, however, are limited to the scope of the organisation, they do not extend beyond institutional boundaries." [START_REF] Klump | Towards Globally Unique Identification of Physical Samples: Governance and Technical Implementation of the IGSN Global Sample Number[END_REF] At the time there was a need for PIDs for physical samples articulated, there was no organization insight to operate such a service: "The concept of IGSN was developed by Kerstin Lehnert at the Lamont-Doherty Earth Observatory in 2004 in a precursor project as the System for Earth Sample Registration (SESAR) [START_REF] Lehnert | SESAR: Addressing the need for unique sample identification in the Solid Earth Sciences[END_REF]. At this time DataCite had not yet been founded and the few first DOIs for datasets were registered through the German National Library of Science and Technology (TIB) [START_REF] Brase | Using Digital Library Techniques -Registration of Scientific Primary Data[END_REF]. TIB saw the need for a persistent identifier system for samples but considered this use case to be out of scope of their DOI operations." (Interview with Jens Klump). Also a membership in "the International DOI Foundation (IDF) to be able to mint DOI independently of TIB was ruled out due to the high fees for IDF membership." [START_REF] Klump | Towards Globally Unique Identification of Physical Samples: Governance and Technical Implementation of the IGSN Global Sample Number[END_REF]). Consequently, it was decided to run the IGSN on a "generic implementation of the Handle. net System, which went into operation in 2008." (Interview with Jens Klump).

Incorporated expertise and best practices as facilitators

A central player in IGSN development (both technically and organizationally) was and is Jens Klump, with whom the consultants conducted an interview. IGSN benefited from his experience in the implementation of DOIs in Germany by TIB Hannover which addressed disciplinary demands that were not met by existing services: "I got to know Kerstin Lehnert at Lamont-Doherty Earth Observatory, and learned about her idea of developing an identifier for geological samples. To me, it was an obvious thing to use persistent identifiers like DOI to identify geological samples, not something homegrown. (...) So we approached TIB Hannover to ask them whether we could use DOI for rocks and Irina Sens said she loves the concept, but it was out of scope of TIB's mandate. So I put down 50 US dollars to buy a Handle namespace. 'Okay, then we do our own thing.'. We just cloned the STD DOI as it was called at the time. And since parts of the infrastructure were built by my team anyway, so that was easy." (Interview with Jens Klump) After these first steps, IGSN focused on its organizational growth and further development, again following a best practice familiar to Jens Klump: "And then DataCite started to emerge and was incorporated in 2009 and then we could see this concept of IGSN growing. And we saw that it wouldn't really flourish if we kept it as an NSF project, as a just purely US based project. So I suggested that we first think about what it should look like and look at the example of DOI and DataCite, and maybe also copy the organizational model. So we did that too, we copied the statutes and founded an 'Eingetragener Verein' (e.V.), went to the German consulate in San Francisco to get it registered, because that American Geophysical Union meeting in San Francisco was the only place where we could get all the founding members into one room. And that's how that started." (Interview with Jens Klump).

Unlike DataCite, however, IGSN focused on community advocacy rather than national infrastructure institutions during this phase of differentiation. Nevertheless IGSN again followed the example of DataCite and incorporated the governance and operation of the central IGSN services into the International Geo Sample Number Implementation Organization (IGSN e.V.).

Since IGSN obviously met a pressing need in the community and no significant alternatives existed, IGSN prevailed as the standard identifier for samples: "Over the past years, IGSN has grown dramatically from a niche solution for petrology to becoming a global identification system for samples with nearly 10 million registered objects. The uptake of IGSN by national geological survey organisations and major collections, as well as the integration of IGSN into the scientific record through links into the scientific literature, make IGSN a strong candidate solution for a globally unique identifier for physical samples" (Interview with Jens Klump).

Obviously, other PIDs for physical objects have been discussed, e.g., the Life Science Identifier LSID, however, these are not gaining acceptance to the extent that the IGSN has: "At the same time, community-specific sample identifier systems have been introduced, most actively pursued in life sciences and geosciences. For example, the bioinformatics and biodiversity communities created an identifier system (Life Sciences Identifier, LSID) to identify samples and biological taxa. Due to various socio-technical reasons, LSID was not adopted, and the community pragmatically decided to discontinue LSID". (Interview with Jens Klump, see also [START_REF] Klump | 20 Years of Persistent Identifiers -Which Systems are Here to Stay?[END_REF].

LSID was based on an urn:nbn namespace without being registered with the Internet Assigned Numbers Authority (IANA), why these IDs are not strictly URNs or URIs. However, the implementation and uptake of LSID suffered from controversy whether the LSID URN approach or an HTTP URIs approach should be followed. Nevertheless, services likeZoobank are still assigning LSIDs to records. 3

Managing growth

In turn, the success of IGSN was so challenging that an organizational and technical realignment was advisable. " [T]he governance and the technical solutions are both in transition at the moment, because one of the things that we did realize was that we were struggling to keep everything going. And I asked for what I at the time called professionalization of the organization, to not run it on a volunteer basis with contributions from the members, but to run it with somebody in charge whose career it is to keep it going. The same path that DataCite had gone. But not necessarily copying that. So we applied to the Sloan Foundation for project funding. (...) And we realized in this project that we needed to change our business model, we needed to find a partner (...)... where we could partner in sharing some fundamental aspects of running the organization. And it then turned out, (...) that DataCite actually was very interested to partner with IGSN. So in May last year, we started negotiating the terms and in late September, we signed a memorandum of agreement between the two organizations to partner on running the technical infrastructure of IGSN. So IGSN, now segwaying into the technical side, is transitioning from being a Handle on its own into DOIs issued through DataCite." (Interview with Jens Klump).

In late 2021 the IGSN e.V. and DataCite agreed that DataCite will operate the IGSN ID registration services and supporting technology. This also means that IGSN identifiers will become DataCite DOIs, and any DataCite member will be able to register identifiers for samples as IGSNs through DataCite. [START_REF] Klump | Towards Globally Unique Identification of Physical Samples: Governance and Technical Implementation of the IGSN Global Sample Number[END_REF]. 4

Adaptable responses to community needs

As mentioned at the beginning of section 2.1, identification systems for physical objects existed, but they did not work across organizations and thus did not ensure, for example, the disambiguation of an object: "Addressing these types of ambiguities was a primary motivation for the development of a globally unique identifier, then called the International Geo Sample Number" (Interview with Jens Klump), so there was a strong community need for a PID meeting their demands.

Another requirement addressed by IGSN is the need to identify not only specific samples, but also physical collections: "IGSN is now both a governance and technical system for assigning and preserving globally unique persistent identifiers to physical samples and aggregates of samples." (Interview with Jens Klump).

Another disciplinary characteristic is the fact that IGSN IDs are assigned not only to objects or collections of objects, but to objects/entities that were necessary for generating the samples: "IGSN can be used to identify related entities that are closely linked to physical samples. Examples are boreholes, mines, outcrops, or 3.

See for instance https://zoobank.org/References/33521a45-4306-4a49-89fc-ac47a015551d 4.

As mentioned, on the 21st of September 2022, DataCite announced that the registration of IGSNs was now technically possible. other sites. They all have in common that they are not samples themselves, but (...) sampling features." (Interview with Jens Klump).

Success factors

Meeting specific needs and knowing these needs of the community Furthermore, the IGSN ID enables the management of different metadata schemas, which allows sub-disciplinary applications and increased the adoption of IGSN:

"Separating the registration metadata of the identifier from the description of the object gives the IGSN system the flexibility to accommodate a greater variety of applications, which may require different metadata profiles to describe their samples, e.g. for different disciplines or use cases." (Interview with Jens Klump).

"Allowing such application-specific metadata profiles gives IGSN agents greater flexibility to describe samples for different applications, e.g. allowing harvesting of certain sample types with their domain-specific description metadata required for domain-specific catalogues and applications [see [START_REF] Devaraju | Towards a web-enabled geo-sample web: An open source registration and management system for connecting geo-samples to the web[END_REF]." (Interview with Jens Klump)

The intensive participation of the communities in the development of these schemes is likely to have had a positive influence on their applicability and adaptation:

"The IGSN Description Metadata schema 5 This flexibility also enabled the transformation/growth of IGSN from a PID for petrology to a PID for physical objects and collections per se: "We had to find some meaning to it, but in the communication, it will just be IGSN. But the question then is what does this mean for the community? It's a very geo and environmental community at the moment, we have some observers from archaeology and material science, but the concept that we develop for broadening the application of IGSN identifiers is by developing this concept of a 'community of communities'. So the kind of disciplinary communities operate by themselves, because they know what they need." (Interview with Jens Klump). This conceptual openness makes ISGN an attractive partner for PID implementations also from other disciplines and contexts: "We were approached by DiSSCo 6 , the Consortium for national history collections in Europe, whether we could provide identifiers for them, and they expected three billion objects. And DataCite had already said, 'No, too big.' And I thought, well, then this is not going to happen tomorrow, this is going to take 10 years, in 10 years time we can do that. So I said yes, of course. But we will have to think of a way how to do this." (Interview with Jens Klump). 7 5. http://schema.igsn.org/description/ and http://igsn.github.io/metadata, see also the crosswalk from IGSN to DataCite metadata, https://support.datacite.org/docs/igsn-id-metadata-recommendations 6.

https://www.dissco.eu/

7.

DiSSCo, the Distributed System of Scientific Collections (DiSSCo) is a research infrastructure planned in Europe to commence implementation in 2024. In order to start out as a FAIRified system, different handle-based PIDs were evaluated by the project to determine their approach to persistent identification. IGSN was one of them, but DiSSCo, after careful evaluation decided to implement a "DOI-driven approach", because of the "substantial achievements, operational experience and reputation of DOI/ IDF to date". [START_REF] Hardisty | A choice of persistent identifier schemes for the Distributed System of Scientific Collections (DiSSCo)[END_REF] Flexible use cases and social, technicalconceptual openness IGSN is governed by an international body, the IGSN Implementation Organization (IGSN e.V., http://www. igsn.org) [START_REF] Klump | Towards Globally Unique Identification of Physical Samples: Governance and Technical Implementation of the IGSN Global Sample Number[END_REF]. In 2021, IGSN and DataCite signed a Memorandum of Agreement and entered into a partnership. This means that existing IGSN ID handles will now be registered IGSN ID DOIs and the handles aliased to the DOIs to ensure that these continue to resolve. DataCite will provide the technical infrastructure and all DataCite members will be able to assign IGSN IDs as well.

The metadata scheme for IGSNs will not be changed, however, because persistent identification of geological samples has very different requirements than the publication oriented DataCite scheme can offer. IGSN's approach of assigning metadata based on decisions by communities of practice 8 while requirements for a basic set of descriptive metadata has been agreed upon 9 is somehow unique. This allows IGSN to be very flexible and attractive for different communities and use cases. For example domain specific community portals, such as the System for Earth Science Sample Registration (SESAR) 10 function as a hub to make samples searchable and accessible.

Community-engagement

It would certainly not be wrong to also mention the trust in the competence of responsible people within the community, who have proven to have the technicalorganizational knowledge (in this case from the DOI application in Germany) to develop a PID application for the community.

Community engagement is vital for PID systems that specifically cater to the needs of a research discipline or community, because features of the service are developed with much closer regards to the communitycentric use cases than generic PID systems (see above). The establishment of a IGSN Community manager new role at DataCite emphasises this critical factor.

Merging with established PID providers

Since a central actor, Jens Klump, was familiar with the DOI implementations by TIB Hannover, the design of IGSN was strongly oriented to the developments at TIB and subsequently DataCite from the beginning: Starting with the cloning of the implementation of DOIs in Germany by TIB Hannover (mentioned in the interview), up to the organizational form as a registered association (Eingetragener Verein, e.V.). The alignment with DataCite was a crucial element in the development of IGSN from the very start: "This includes the choice of Handle as the underlying persistent identifier protocol, which was chosen in 2008 to keep IGSN as much as possible interoperable with DataCite." (Interview with Jens Klump) As this approach was not only based on familiarity with TIB/DataCite, but also on the consideration of alternatives, not only did familiarity work as a trust factor, but also the evaluation of DataCite as a best practiceespecially its capability to build or integrate communities. This trust in DataCite's ability to manage communities was underpinned by DataCite's provision of resources, which of course further strengthened the trust:

"Because what I actually didn't expect from DataCite was the commitment to this partnership. So DataCite did go for funding to do this, but they're committing two persons to implement IGSN. So they just hired a community manager. And they are in the process of hiring a technical support role to help IGSN members on the technical level to make the transition. But the samples Community Manager is somebody who will work both with the existing IGSN membership who are all DataCite members, and with DataCite members who might be interested in registering PID for physical samples to get them on board with this process. (...) For this person, it will be much easier to use the existing DataCite network to approach potential new users for this aspect, for something that they already know. (...) They are already using DataCite DOI. They're just not maybe using the resource type physical object. I actually would say, IGSN is in a quite privileged position at the moment of having this fantastic support from DataCite, that they commit two people to working with this community. And through the partnership agreement there's a partnership steering group that links between the two organizations". (Interview with Jens Klump). 3. Issues around risks and trust regarding the emergence of new PIDs

Sustainability

In the Interview, the IGSN representative strongly emphasized the role of sustainable business models, just as he and Robert Huber did in their publication from 2017: "It might be a bitter pill to swallow for some members in the research data community wary of all things commercial, but business models are essential aspects of PID systems -sustainable PID systems do not come for free." [START_REF] Klump | 20 Years of Persistent Identifiers -Which Systems are Here to Stay?[END_REF]

Community requirements

This sustainability is complemented as a trust marker by the community's perception that the PID is valuable for it, that it is functional and serves their requirements: "I think the key factors here are that there's a sustainable business model. Because at the end, you have to have people that run it. It's a socio-technical system, where the easier part is running the technology, the more difficult part is the social part, to have the trust of the community that this is actually something that is worthwhile, that it works, it serves their needs." (Interview with Jens Klump). This point can also be witnessed in DiSSCo's decision process. Following Park et al. (2001) they noted that: "Consistent, high-quality and excellent delivery of PID services built behind a branding that creates instant recognition for PIDs of the chosen scheme as the unambiguous pointers to specific accurate and authentic digital data about a specimen, including an unbreakable link to the corresponding physical specimen acts to confer authority. Trustworthiness should follow. Information quality is the strongest factor to influence organizational benefits through perceived usefulness and user satisfaction." They concluded that "operating under another Handle-system prefix than those used by IDF and ePIC is the substantially weakest option because of the difficulties associated with introducing an identifier that is not perceived to be a DOI." [START_REF] Hardisty | A choice of persistent identifier schemes for the Distributed System of Scientific Collections (DiSSCo)[END_REF] In its early days, before it partnered with DataCite, IGSN itself sought to establish trustworthiness through cooperation with a reputable institution: "We try to mirror that in IGSN, where, even

Brand effects

Indicators of trust

Jens Klump also introduced an indicator that can provide information on the extent to which the community (or at least organizations as representatives of the community) trusts a service, its willingness to commit to and invest in the service 13 :

"So one important measure for me whether they trust in the system is whether they invest in it. Whether they put resources to it. This is in particular, with government agencies, when they make a commitment. Once they make this a line item, they stick with it. But to get to that point is hard. So they have to be convinced it's worthwhile going through all this. So that's from an infrastructure perspective." (Interview with Jens Klump)

Away from organizations, with individuals as representatives of a community, indicators of trust are more difficult to identify, most likely as demand for the service:

"And the user perspective, it's much more difficult to pinpoint whether the community has trust in the system or not. It's because the uptake is difficult to measure. (...) So when we then see people asking for the service to be provided, then … this is also an indication of trust. With other homegrown identifier systems, we wouldn't see the community advocating anywhere that this should be used and see the uptake on the provider side is also not that frequent." (Interview with Jens Klump)

Issues of risks

So far, no elements of risks have been identified in this case study, even though the signs of the partnership with DataCite are very positive (outreach, possible adaptations by other communities, investment in the form of human resources), possible resulting risks (overburdening of the provider DataCite or loss of IGSN's agility through cooperation with DataCite) can only be identified over time.

  11. ISO. (2010). Guidelines for bibliographic references and citations to information resources (ISO 690:2010) (Standard No. ISO 690:2010). Geneva, Switzerland: International Organization for Standardization (ISO).

  is developed by the IGSN members with inputs from a community of practice in the earth and environmental sciences. It is used to catalogue a minimum set of descriptive properties of samples and sample collections, such as sample type, material type, contributor, and sampling activity, to aggregate catalogues of samples across IGSN agents into overarching portals. This schema was deliberately kept general to allow the compilation of a global catalogue of, e.g., geological and biological samples and sample collections." (Interview with Jens Klump)

  "The reason why we decided to partner with DataCite was because of the now mature model of the experience of bringing new members on board. And today, they are eager to broaden their services to other applications. And that they started out with something that was very bibliographical. So the original metadata starting from STD DOI were based on ISO 690 11 bibliographic metadata, that was the kernel and describes the intended purpose because it all had to flow into the TIB catalogue, because there were no portals at the time, portal was a novel thing. And then things changed over those years. But it's still that DataCite is a very bibliographic heavy system, but now other applications want to use persistent identifiers, like ROR and instruments, and others are now approaching DataCite.And DataCite is open to that. But with IGSN, they also saw an opportunity to bring a quite mature community on board, with a different use case, where the system already has 10 million identifiers registered, that's not much smaller than DataCite." (Interview with JensKlump)

	8.

https://igsn.github.io/communities/ 9.

https://igsn.github.io/metadata/ 10. https://www.geosamples.org/

  The remark that national libraries, while having the trust advantage of having existed for centuries, are technically somewhat less agile, may lead to the idea of an ideal picture of a PID provider which combines both characteristics, a long-standing existence and a willingness to innovate technically, with solid funding on top (which perhaps was manifested to some extent in the TIB Hannover and DataCite): "So you can see these separate lines where, technically it's not that difficult, but you need to have a strong organizational base that can run this for decades. There has to be money coming in. And you have to find a way that it does serve the community, solves the problems and is seen as trustworthy." (Interview with JensKlump)

	will be piecemeal, it will be very hard. But if we get	the identifiers to us with the checksum appended. No,
	those large organizations on board, we can demonstrate	that's not how it works. We have more than a million
	trust, and we can grow very fast."	identifiers already! This is not that we're pushing 40
	(Interview with Jens Klump).	books per day across the counter".
		(Interview with Jens Klump)
	Even DataCite benefits to a certain extent from the brand
	value of another institution, the TIB Hannover, which
	operates the DataCites office: "Well, I think what you said
	earlier about the organization having a good backing,
	then it has its own sustainability and resilience. I think
	TIB offered a very fortunate combination in that they
	were well established, but also forward looking. And
	that DOI wasn't the only opportunity where I could
	see them realizing the potential of a new
	development, seizing it. So with TIB, it's a very good
	combination. But to have a solid foundation, I think,
	was really important. And in the early days getting
	from DFG funded project to being a line item in the
	TIB budget was a really important thing."
	(Interview with Jens Klump)
	3.4 Technical reliability and up-to-dateness
	As another trust component, the expert makes the
	technical reliability and up-to-dateness, which spoke in
	the evaluation phase against URN and for Handle:
	"And when we evaluated and implemented URN, we
	ran into an interesting problem there because here we
	had to deal with a kind of immature technology. There
	were parts in place and others were promised, but they
	never materialized. (...) And in the URN example, this
	was an interesting learning experience in service quality.
	So the service was very reliable, because it was run by
	the National Library. But it was so cumbersome. But
	we're talking about 2004 here, so Web Services is
	something new. When Michael Diepenbroek and I
	asked TIB to provide us with a web service endpoint, at
	the next meeting, we were presented with a web form and we just looked at him quizzically: 'What?' There was a bit of a cultural divide there. And the National Library worked in the same way that for us to register URNs for datasets, they wanted us to send Excel spreadsheets by email, and then they would return	though it started out with working with individual researchers, very early on we said we must work with the National Geological Surveys. Because they are trustworthy, and they have large collections. Working with individual researchers

13. Perhaps the caveat might be: provided the community has funds and can invest sovereignly to support the service.

https://blog.datacite.org/start-registering-igsn-ids-with-datacite-now/

Rationale

Building a community-driven PID

See Kotarski et al. (2020)

Issues around risks and trust regarding the emergence of new PIDs

Case study 3. Issues around risks and trust regarding the emergence of new PIDs

Authorship

This case study has mainly been written by Ulrich Herb (Saarland University, ORCID https://orcid.org/0000-0002-3500-3119) within a team of consultants including Pablo de Castro (University of Strathclyde and euroCRIS, ORCID https://orcid.org/0000-0001-6300-1033), Laura Rothfritz (Humboldt University Berlin, ORCID https://orcid.org/0000-0001-7525-0635) and Joachim Schöpfel (University of Lille and euroCRIS, ORCID https://orcid.org/0000-0002-4000-807X) under the umbrella of scidecode science consulting (ROR https://ror.org/02c0bjd31). The work has been overseen by the Knowledge Exchange Task & Finish Group whose composition is listed at https://www.knowledge-exchange.info/event/pids-risk-and-trust.


Pablo De Castro

Ulrich Herb

Laura Rothfritz

Joachim Schöpfel

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

The RePEc Author Service (RAS) is a useful addition to the DAI case study, as it has similarities to DAI in that it is a non-profit, community-based service, but also differences in that it is disciplinary, and especially as it survived the advent of ORCIDs.

RAS is notable for its connection with a variety of other services (document download statistics, bibliometric analysis, citation counts, person and institution rankings) that reside within a kind of RePEc service family.1 Strikingly, RePEc or the RAS operates its own affiliation manager that identifies institutions down to the department level 2 and neither implemented ORCID and ROR nor synchronizes data with these services. Selecting RAS as a case study provides valuable information about why RAS (despite the competing ORCID and ROR initiatives) still exists (while, for example, the DAI no longer does) and how this relates to community support and funding. A first insight is that RAS, perhaps more than DAI, which may have been a more organisation-driven effort, is actually being adopted by researchers themselves and by that is (just as the PIDs for research instruments and facilities or IGSN) a technical PID. Possibly its disciplinary nature also plays a role for its resilience, contributing more to the profiling of institutions and individuals (also in the linked RePEc cosmos). At the time when the DAI was operational, there was no application for this use case with DAI, whereas it is evident in ORCID through integration with databases such as Web of Science or Scopus. Also of interest is the question of funding (also to be retrospectively considered ) and other tools as a kind of academic genealogy tree for economics (RePEc Genealogy 7 ).

During the registration process, authors are required to choose an affiliation from RePEc's affiliation manager EDIRC (Economics Departments, Institutes and Research Centers) or to suggest a new one. Newly suggested affiliations are obviously added automatically to the service (and also removed after some time, if no publications are linked to them), the affiliation index is not based or synchronized with ROR, also there is no integration of ORCID into the RAS -authors may not even add an ORCID to their RAS profile. EDIRC covers according to its website currently 15,076 institutions in 232 countries and territories. 8

According to an email conversation with RePEc, the service considers including features that allow adding and import other identifiers, perhaps WikiData, for starters.

The utilization of the RAS profile within other RePEc services may be illustrated especially by its integration in IDEAS, which displays the RAS information 9 in the IDEAS profile. It compromises the basic personal information, information about affiliations (which may be split proportionally between several organizations), publications, citations to these (both from scientific publications and blogs), download statistics, a researcher's position in an abundant number of rankings, co-authorship networks (providing network analysis measures as closeness, betweenness, centrality, etc.). 10 RAS is also used within the CitEc service to generate more detailed citation data and bibliometric information (as e.g. co-authorships or recent citations) 11 :

8.

https://edirc.repec.org/ 9.

In the following, Andrei Shleifer's profile is used for illustrative purposes, https://ideas.repec.org/e/psh93.html 10. https://app.collec.repec.org/app_direct/collec_app/ 11. http://citec.repec.org/p/s/psh93.html

Uptake

While ORCID has (according to its website 12 with date of 20th September 2022) 14,959,053 registered IDs, RAS indicates (as of 20th September 2022) 65,169 registered authors (which have authored 1,878,499 items listed in RePEc) 13 . RePEc states that its data is re-used e.g. in the databases EconLit, EconStor, OpenAIRE, Sciverse and EBSCO databases. Nevertheless, it is unclear to what extent these very rich data and valuable services of RePEc are integrated in external databases or services. Most databases mentioned by RePEc as re-using its information are probably simply importing its bibliographic data. Also, the Leibniz Information Centre for Economics (Leibniz-Informationszentrum Wirtschaft ZBW) does not reuse RePEc PIDs (RAS and EDIRC) in its own services, but citation data from CitEc. Nevertheless, in 2017 the ZBW used Wikidata to match around 3,000 authors with RAS IDs and the Integrated Authority File IDs (GND) by their publications 14 to allow a more accurate attribution of publications to authors in their EconBiz 15 portal.

Sustainability & Governance

Shortly after the acquisition of SSRN by Elsevier, RePEc published a statement 16 pointing out that it would be "impossible" to buy RePEc. The key argument says that RePEc is not attractive for commercial stakeholders, as it (even though generating values for the community it serves) has no financial value. Operating the service without secure funding is only possible as RePEc is optimized to run at extremely low cost, so its services are offered for free. This in fact requires volunteer work 17 and sponsorship for hardware, hosting and bandwidth. As all RePEc data is openly available (even in public domain 18 ) there is, in RePEc's opinion, no chance of selling its data to generate noticeable revenues. In fact, this open data approach would allow to re-build in the case of RePEc's failure its services freely from scratch. This point was also made several times in expert interviews during this study. The fact that RePEc appears to have very low operating costs is an indication of resilience and sustainability, which is only found in other services at a higher investment. Considering RePEc's launch already back in 1997 this approach so far did not prove to be unsustainable. Sticking to it, RePEc is asking its community for support in a range of areas as for instance RePEc archive maintainer (curation of publications submitted by an institution), NEP report editor (dissemination of new online working papers via weekly reports), editor for the Munich Personal RePEc Archive (a kind of orphan repository), help with EDIRC, RAS, RePEc Genealogy, RePEc Biblio, RePEc's Plagiarism Committee. RePEc also asks to contribute hardware or hosting services. Regarding EDIRC RePEc mentions: 19 "This database has grown tremendously, and help is needed to maintain it." This sheds light on the administrative and curation burden when operating an affiliation manager. The support needed with RAS is described as help "in monitoring the activity on the service and managing the profiles of deceased authors."

12. https://orcid.org/statistics 13. https://ideas.repec.org/stats.html 14. https://zbw.eu/labs/en/blog/wikidata-as-authority-linking-hub-connecting-repec-and-gnd-researcher-identifiers 15. http://www.econbiz.de/ 16. https://blog.repec.org/2016/05/17/repec-is-independent-and-cannot-be-bought/ 17. As of March 29th, RePEc mentions twelve team members, https://ideas.repec.org/team.html 18. A corresponding statement can be found here: http://repec.org 19. https://ideas.repec.org/volunteers.html

Funding parties

Information about the funding of RePEc are spare and scattered around its website, this mentions in different sections the Federal Reserve Bank of St. Louis, which offers hosting capacities since 2011 20 . This organization is also the employer of Christian Zimmermann, who is obviously one of the main contact persons for RePEc, why it may be considered RePEc's most important sponsor. In an email conversation, Christian Zimmermann also stated that he would be allowed to spend some of his working time on RePEc.

Additionally, in the context of the RePEc service ArchEC that provides long-term archiving of RePEc templates and full-text files there are three sponsors mentioned 21 : a) the Fondation Banque de France, b) "an important economics research organization based in the United States, who pay for the server" (probably the Federal Reserve Bank of St. Louis), c) the Open Library Society in New York. The last one mentions on its website 22 one of RePEc's establishers back in 1992 23 as its founder, Thomas Krichel. This makes it seem possible that the Open Library Society was set up to organize external funding through third parties for RePEc.

Not only RePEc as such is hosted by a sponsor, the same is true for at least one of its services, the coauthoship analysis tool CollEC, 24 that is according to its website hosted by Symplectic. Symplectic is one of the services offered by Digital Science, a commercial provider in research analysis. Also, EconPapers, another RePEc service, relies on funding, in this case by the Örebro University School of Business. [START_REF]has been overseen by the Knowledge Exchange Task & Finish Group whose composition[END_REF]

Issues around risks and trust

RePEc as an (un-)organization

RePEc's organizational form seems quite undefined. It is also not clear (at least from an outside perspective) how the community is engaged in plans for further development of RePEc and RAS.

There are two mailing lists available, RePEc-announce (with general information about RePEc developments) and RePEc-run (with discussions of technical matters regarding RePEc services), but the overwhelming number of mails on the first one are postings contributed by two RePEc team members while access to second list's archive is restricted. One feedback channel may be the volunteers supporting RePEc's operation through their manpower -even if there is no indication to what extent the volunteers have any influence on any strategic or organizational decisions.

The degree to which RePEc and its PIDs (RAS and EDIRC) depend on volunteers may reflect a sort of weakness (risk) and strength (trust) at the same time: Having a larger volume of continuous funding or another more formalized governance structure might weaken the responsibility the community feels for RePEc. On the other hand, this kind of loose organizational structure requires a lot of trust in the service and the people behind it for authors and institutions to make use of it. Mentioning this, however, the age structure of the RePEc makers and team members 26 may be seen as critical for a service obviously relying so much on individuals, their knowledge and expertise. According to an email conversation with RePEc both issues of technical viability through switching to up-to-date web/ database techniques and team members succession plans are to be addressed.

Funding & Sustainability

Apparently RePEc organizes its funding `through the Open Library Society (instead of e.g. SCOSS) which was launched by one of the inventors of RePEc which may indicate a strong emphasis of the service's independence.

`within its own organizational network, what can -if successful -of course be considered in indicator of trust:

One reason for this mistrust in centralized approaches to organize or finance infrastructures may lay in the fact that ORCID used RAS data as seed data to populate its databases, but deleted the RAS identifiers afterwards (as reported by Christian Zimmermann), which probably provoked the feeling of having been exploited.

Focussing on the sustainability, RePEc seems either to rely heavily on external funding without revealing much information about that or really manages to operate quite successful with its minimum cost approach. Having a look at the huge number of services that were built around RePEc, some surely are of great importance and have 26. https://ideas.repec.org/team.html So one important measure for me whether they trust in the system is whether they invest in it.

Whether they put resources to it. This is in particular, with government agencies, when they make a commitment. Once they make this a line item, they stick with it. But to get to that point is hard.

significant value, while others perhaps may be results of some sort of "play with the data" attitude. This does not necessarily indicate a risk, it may even reflect that RePEc even is operating his business so balanced that they can even afford to set up services without any specific demand for an evident use case.

Cross-functional integration vs. functional self-restraint

The fact that the PIDs operated by RePEc (RAS, EDIRC) seem not be integrated in external services nor seem to offer any added values such as automated metadata retrieval may be considered either a risk (as this may reduce its acceptance in an ecosystem of increasing demands on interoperability), but may also be an indicator that RePEc is a solid system in itself with solely disciplinary use cases and therefore may not need interoperable functionalities.

Evidence of functionality and community needs

At first, operating a service as RePEc since 1997 (and RAS since 1999) may be considered a very strong trust indicator, the more as it was obviously able to cover its operational expenditures even long before invests in open infrastructure were broadly discussed.

The service itself is still considered to be highly significant in Economics, especially because of the researcher and institution rankings, especially of non-university economic research, and services as citation counts. For example, the ifo Institut -Leibniz-Institut für Wirtschaftsforschung an der Universität München e. V. uses RePEc data intensively to produce its rankings. 27

Open Data

RePEc's own argument in its trustworthiness, that data in public domains allows anyone to set up the service again for free (a principle also put forward by interviewees), is true, but assumes that there are documented database dumps available, which might not be taken for granted.

Because well, okay, there are a few issues here and there, but it's been running for a very, very long time already.

Summing up

Contrasting RAS (RePEc and EDIRC) against e.g. the Digital Author Identifier (DAI) or ORCID (or ROR) the RePEc services seem to benefit from serving the needs of a community of scientists and organizations, whereas ORCID and ROR serve -at least in Economics -more the needs of libraries, universities, funding agencies and publishers, so co-existence of RAS/ EDIRC and ORCID/ ROR seems possible, unlike DAI which addressed the same needs as ORCID. RePEc seems to be a service whose disappearance would pose very serious problems for the Economics community, since it offers functions that are highly valued and widely used in the community. RePEc never gave up the sovereignty about technical, organizational and strategic decisions -what probably was only possible as a result of the trust in it that stimulated financial and human resources support by organizations that benefit from RePEc. Just as with IGSN (see the respective case study) the benefits the service offers strongly derives from (and depends on) the incorporated knowledge of some of the individuals who build/run the service. However, while IGSN seeks solidity by following best practices, largely generic solutions, and seeking strategic partnerships, RePEc appears to be a one-of-a-kind technical/organizational entity whose persistence depends very much on individual commitment and knowledge -success factors that may be difficult to transfer to others. Hence, the issue arises of how to keep RAS operational if, for example, it is not possible to transfer or generalize the expertise concentrated in a few. This raises the concern whether it would be possible to migrate RAS to other PIDs such as ORCID in order not to lose its functionalities altogether. This example may be hypothetical in the RAS case, since the discontinuation of RAS would presumably be accompanied by that of RePEc -however, this poses the general question of procedures for the orderly replacement of one PID system by another.

And that's really important that organizations and infrastructures are addressing these and so, as an example, at DataCite, making our data far available and the CC0 and making it public deposits or archive of that and a data dump available is important, having open API is having the code Open Source, these are important insurance mechanisms to make sure that the community has that assurance that it would be long term that these things would still be in place, that technology and the date would not disappear.

Rationale

RePEc and its Author service (RAS)

Case study 2. RePEc and its Author service (RAS)

Issues around risks and trust

Authorship


Nour Chahrour

Jean-Marc Tacnet

Christophe Bérenguer

Economic Efficacy Assessment of Deteriorating Protection Structures Subjected to Natural Phenomena in Mountains

Natural phenomena in mountains pose threat to people and material assets located downstream. Different types of protection structures are implemented in mountains to resist natural phenomena and to protect vulnerable exposed elements. However, these structures deteriorate over time and the level of protection they provide is reduced, which raises for example the issue of their maintenance. To be economically effective, there should be a balance between the level of protection provided by protection structures to downstream elements at risk and the expenses spent on them (e.g., maintenance costs), as done in classical cost-benefit analysis. This study aims in proposing a conceptual model that estimates the evolution of risk level induced by natural phenomena in mountains while considering different deterioration levels of protection structures. This is achieved by performing risk analysis that integrates hazard, vulnerability and exposure assessment. Cost-benefit analysis is then adopted to assess the economic efficacy of protection structures. Finally, a simple numerical application is carried out to clarify the proposed model.

INTRODUCTION

Mountainous regions (e.g., French Alpes) are usually exposed to different types of natural phenomena such as torrential floods and debris flows. These phenomena induce risk in downstream areas where vulnerable issues (e.g., people, houses, roads) are located. Depending on their nature and intensity, they can result in direct damages (e.g., causalities, injuries, destruction) and/or indirect damages (e.g., infrastructure disruption). Such consequences prompt risk managers to acquire a comprehensive knowledge about the dynamics of natural phenomena in mountains as well as the means and alternatives for protecting people and properties. Indeed, several types of protection structures (e.g., check dams, retention dams, dykes) are implemented in mountains to control torrents. These are civil engineering structures that act on reducing the causes of the phenomena (e.g., erosion) or their consequences (e.g., overflows, deposit).

During their lifetime, protection structures are exposed to several deterioration mechanisms due to their aging and the high intensity phenomena they are subjected to. Consequently, efficacy level of these structures is reduced over time. The efficacy of protection structures corresponds to the ratio be-tween their capacity and functional objectives conditioning the risk reduction level they provide to downstream elements at risk. It is equivalent to the performance level of the structure expected at the design phase, after construction and in service. Assessing the dynamic efficacy of a protection structure involves evaluating three components: structural, functional and economic efficacy. The structure should be stable from a structural point of view (e.g., external and internal stability). Moreover, it should be operating while achieving all the desired functions (e.g., bed stabilization, flow centering, material storage). To be economically effective, the cost of damages triggered after natural phenomena should be less than the expenses spent on the construction and maintenance of protection structures, both considered in the same time period.

Recent studies have focused on developing stochastic approaches that make it possible to model and analyze the physics behind the deterioration process of protection structures when subjected to natural phenomena over their lifetime [START_REF] Chahrour | Deterioration modeling and maintenance assessment using physics-informed stochastic petri nets: Application to torrent protection structures[END_REF][START_REF] Chahrour | A surrogate deterioration model of debris retention systems towards cost-effective maintenance strategies and increased protection efficacy[END_REF]. The main objectives behind these approaches were to assess the technical efficacy (structural, functional) of protection structures and to support their maintenance decisionmaking. Moreover, Carladous (2017) has developed a decision-aiding model using cost-benefit analysis (CBA) in order to choose which protection measures to implement based on an economic efficacy assessment, which corresponds to the efficiency of reducing the risk induced by the natural phenomena and the cost of implementation of these measures. Nonetheless, the latter study has not considered assessing the evolution of the economic efficacy of protection structures over time. This means that the assessment was carried out from a static point of view, assuming that there was no technical efficacy reduction due to the deterioration of structures over time. Consequently, no maintenance operations were taken into account.

This study aims to fill the gap in the literature by proposing a simple model that makes it possible to estimate the dynamic (i.e., over time) economic efficacy of protection structures in combination with the evolution of their technical efficacy over time. This paper is structured as follows: Section 2 provides a brief description of the studied context. The methodology developed to achieve the desired objectives is presented in Section 3. Section 4 describes a simple numerical application, in which the risk and cost-benefit analyses are carried out. Conclusions and perspectives are provided in Section 5.

TORRENTIAL WATERSHEDS & PROTECTION

STRUCTURES Torrential watersheds are located in mountains and are physically composed of three zones (Figure 1) as presented below [START_REF] Surell | Étude sur les torrents des Hautes-Alpes[END_REF].

Receiving basin: upstream area exposed to intensive precipitation (storms). It is a run-off production area and sediment supply source.

Flow channel: a narrow and steep path at which the torrential phenomenon (mixture of liquid and solid materials) flows.

Alluvial fan: downstream flat area where the transported flow is deposited. It involves vulner-able elements such as people, houses and infrastructures.

Intense rain events that occur in steep torrential watersheds lead to fast-moving flows (e.g., clear water floods, debris flows), which may be very destructive. The particular features of torrential watershed (steep slope, narrow channel) enhance the capacity of the flows to erode banks and to transport and deposit materials on fans where elements are risk are located. The impact and volume of the deposited materials could disrupt infrastructures (e.g., obstruction of roads), destroy houses and industrial structures and generate causalities. In France, risk management in torrential watersheds is largely based on structural protection measures. Structural measures are mainly civil engineering structures generally constructed along the flow channel (e.g., series of check dams) and in the alluvial fan (e.g., retention dam, dykes). These structures aim to provide protection by reducing the risk level imposed on downstream areas.

Protection structures do not function separately. The objectives of protection are only achieved within a protection system composed of several structures grouped together so that they participate collaboratively in protecting socio-economic assets. The efficacy of the overall protection system in reducing the risk level decreases with the increase of its deterioration level. Consequently, the system should be regularly inspected and maintained. However, these interventions cost much. This raises the following question: Is this protection system efficient from an economic perspective? In other words, does the total cost spent on the protection system (including construction, site visits and maintenance costs) exceed the benefit (reduction in total risk value)? Another key question is to know whether the protection system will still be economically effective when it deteriorates over time (i.e., after taking depreciation into consideration)? This study addresses these questions through the methodology developed in the next section.

METHODOLOGY

Protection System Efficacy Reduction

As mentioned before, the reduction of the technical efficacy of a protection system affects the risk level imposed on downstream exposed elements. Consequently, information concerning the deterioration process of the protection system should be acquired. This process can be defined as the evolution of the system from one deteriorated state to another as shown in Figure 2. In this study, three states of a protection system are considered: new, poor and failed. These states can be defined based on degradation indicators reflecting the efficacy level E of the system as presented below:

State 1: E 1 < E ≤ 1 new system State 2: 0 < E ≤ E 1 poor system
State 3: E = 0 failed system where 1 corresponds to maximum efficacy level, 0 corresponds to total failure and E 1 is an intermediate threshold that separates states 1 and 2.

Generally, the deterioration process of any deteriorating system is stochastic. The crucial elements needed for representing this process are the probability laws associated to the transition times between the defined states of the system. Figuring out these laws is not an easy task, especially when no or few monitoring data are available. [START_REF] Chahrour | Deterioration modeling and maintenance assessment using physics-informed stochastic petri nets: Application to torrent protection structures[END_REF], has developed a physics-based model that makes it possible to estimate these laws through physically modeling the deterioration of protection structures over time. Other researchers usually assume these laws based on available data or expert assessment. Most of them assume an exponential distribution because of the simplicity in considering a constant deterioration rate. The probability density function presenting the law of transition times from state i to state j following an exponential distribution is given by:

f i-j (t) = λ i-j exp (-λ i-j • t) (1)
The mean transition time between states i and j can be then estimated as follows:

E(T i-j ) = 1/λ i-j
(2)

Risk Analysis

Generally, risk induced by a natural phenomenon is defined as a combination between hazard, vulnerability and exposure. For each type of natural phenomenon, hazard is a combination of its probability of occurrence (likelihood) and its intensity, which reflects a physical quantity describing the phenomenon (e.g., velocity). Vulnerability represents the potential damage rate relative to the intensity of the hazard. Exposure refers to the combination between elements that are exposed to the hazard and their value (e.g., in euros). This definition of risk, given by Eq. ( 3), is provided by the intergovernmental panel on climate change (IPCC).

Risk = Hazard

Vulnerability Exposure

= probability ⊗ intensity damage potential elements at risk ⊗ value (3)
where the symbol ⊗ corresponds to a combination between the terms defining a risk level. Depending on available data, risk assessment could be either based on discrete or continuous modeling of its components. Discrete modeling is much simpler to carry out, in which only four qualitative scenarios, representing the likelihood of a natural phenomenon, can be considered: exceptional, rare, occasional and frequent. On the other hand, continuous modeling provides better estimate of the risk but is more complex to obtain. It requires more information concerning the time series of the hazard, the exposed assets and the vulnerability of each. In this study, the methodology developed to evaluate the risk considers continuous modeling of its components. However, the modeling will be based on several assumptions, in which the goal is to show the principles behind the evolution of quantitative risk analysis considering deterioration states, which is not yet tackled in the context of torrential risk. To carry out this analysis, the following steps should be accomplished.

Modeling the Hazard

The first step concerns generating the "Intensity I -Probability P" curve, which characterizes a hazard linked to a specific type of natural phenomenon. This curve represents the probability of occurrence of an event (e.g., storm) that has the potential to trigger a dangerous natural phenomena (e.g., debris flow) of a given intensity (e.g., velocity of the flow) to occur in a specific area and time interval. It can be built using available historical databases where the intensities and the return periods (T = 1/P) of the events that have occurred in the past are recorded. If this data is available, a law that best fits the observed data can be assumed. If not, the modeling can be based on experts' assessment.

The presence of a protection system in a torrential watershed acts on reducing the intensity of natural phenomena. Consequently, for each state of the system (i.e., for each technical efficacy level), the "Intensity I -Probability P" curve should be established. In the case where system is in state 1 (new system), the intensity of the phenomena is reduced by a ratio α 1 and will be defined as I 1 . If the system is in state 2 (degraded system), the intensity is reduced by a ratio α 2 < α 1 and will be referred to as I 2 . In the case when the system is in state 3 (completely failed), it is assumed that as if there is no protection system. Therefore, the intensity I of the phenomena will not be reduced.

α 1 and α 2 are intensity reduction factors to be defined based on expert assessments. Moreover, these reduction factors can be only applied when the intensity of the phenomenon is less than a specific threshold I th , to be also defined by experts.

Estimating the Number of Exposed Assets

The second step concerns estimating the number of downstream assets, which are touched (impacted) by a natural phenomenon. In fact, the area reached by a natural phenomenon varies depending on the probability of propagation of the phenomenon given the fact that it has already occurred.

In this study, it is assumed that all the assets implemented in the reached area are touched by the phenomenon. To demonstrate calculation principles, a relation between the reached area A reached and the occurrence probability of the natural phenomenon P is assumed as follows:

A reached = A (1-P) max (4)
where A max is the maximum area that can be reached by any natural phenomenon.

Assuming that all the material assets have the same area A asset , the total area of touched assets A total assets and the total number of touched assets N touched assets can be obtained using Eq. 5 and Eq. 6.

A total assets = β • A reached

(5)

N touched assets = A total assets /A asset (6)
where β is a constant occupation rate reflecting the density of construction in the reached area.

Modeling the Damages on Assets

The third step concerns constructing the physical vulnerability of the assets exposed to risk, which is given by a "Damage rate D -Intensity I" curve. The intensity of a natural phenomenon is associated with a damage rate, which is a physical quantity representing the percentage of damage caused on an asset. Indeed, the asset may be partially or totally destroyed depending on the intensity of the phenomenon. [START_REF] Kang | The physical vulnerability of different types of building structure to debris flow events[END_REF] has carried out a nonlinear regression analysis to relate the damage rate to the intensity of debris flow events. Different relations were obtained depending on the intensity parameter. For example, when considering the intensity parameter I of debris flows as the flow velocity υ (in m/s), the relation will be:

D = 1 -exp(-0.0094I 2.775 ) (7)
Note that D is the damage rate in the case when there is no protection system or in the case when the system is in state 3. D 1 and D 2 , corresponding to the damage rates in the case when the system is in state 1 or 2 can be also obtained using Eq. 7 by replacing the intensity I with I 1 and I 2 respectively.

Estimating the Material Losses

In this step, the objective is to estimate the total cost of the losses triggered after natural phenomena. This is given by a "Material loss L -Probability P" curve. In this study, it is assumed that only material losses (direct damages: assets' destruction) are considered. This means that indirect damages (e.g., human mortality, impacts on the environment) are not taken into account. The cost of material losses L (in C) can be estimated using the formula developed by [START_REF] Rheinberger | Dealing with the white death: Avalanche risk management for traffic routes[END_REF] as follows:

L = (1-ε D )•D•(1-ε E )•N touched assets •A asset •V asset (8
) where ε D is the damage reduction rate linked to vulnerability reduction, ε E is the exposure reduction rate and V asset is the cost of asset (in C/m 2 ).

Note that L is the cost of material losses in the case when there is no protection system or in the case when the system is in state 3. L 1 and L 2 , corresponding to the material losses in the case when the system is in state 1 or 2 can be also obtained using Eq. 8 by replacing the damage rate D with D 1 and D 2 respectively.

Evaluating the Risk

The final step is to evaluate the risk level, i.e., the expected financial cost of the risk induced due to a natural phenomena. This is achieved by estimating the area under the curve presenting the material losses multiplied by the probability. To calculate this area, the trapezoidal method can be used.

Since three different states of the protection system are considered, three different curves presenting the material losses are obtained. Consequently, each curve will provide a risk level. For states 1, 2 and 3, the risk level is respectively defined as R 1 , R 2 and R 3 .

Cost-Benefit Analysis

Cost-benefit analysis (CBA) is a method used to assess the potential benefits and costs of a specific decision by assigning monetary values to its outcomes. The main objective behind CBA is to determine whether the benefits outweigh the costs of investment and maintenance and finally if building the protection is worthwhile.

To assess whether a protection system is economically effective, a comparison between the risk level in the absence and in the presence of the protection system should be performed. Furthermore, to estimate the benefits (in C) of a protection system, the cost of its construction should be typically considered as an initial cost, also known as a "t = 0" cost. This includes all expenses that are incurred at the beginning of the project, such as materials, labor, equipment, and other miscellaneous expenses. However, since the protection system deteriorates over time, the cost-benefit analysis should also include the ongoing costs (e.g., maintenance costs) and the benefits of the project over its lifetime. This is due to the fact that as the state of the system evolves over time, its efficacy level is reduced, which in turn leads to a decrease in risk reduction as compared to when it was first put in place.

In this study, it is assumed for the sake of simplicity, that the deterioration of the protection system is continuous in time (as shown in Figure 2). In other words, maintenance operations are not carried out over the lifetime of the system. In this case, the costs C c spent on the system are only those involved in the initial construction operation. Consequently, the evolution of the protection system's benefits B over time can be estimated as follows:

For t = 0 -→ B = (R -R 1 ) -C c For 0 < t ≤ T 1-2 -→ B = R -R 1 For T 1-2 < t ≤ T 2-3 -→ B = R -R 2 For t > T 2-3 -→ B = R -R 3
where R is the risk level when there is no protection system.

NUMERICAL APPLICATION

This section presents a simple numerical application of the developed methodology. Firstly, the risk levels in the absence and in the presence of a protection system are assessed. Secondly, the economic benefits behind the implementation of a protection system are estimated under simplified asumptions. A max (km 2 ) A asset (m 2 ) V asset ( C/m 2 ) β 1 100 2000 0.4

Absence of Protection System

The available data necessary for hazard modeling are those related to the natural phenomena occurring in the Claret torrent in France. This torrent is very active and it is characterized by a steep slope and high sediment potential. It is mainly subjected to debris flow events of different volumes. The obtained data are the volumes V (in m 3 ) and the return periods T (ONF-RTM, 2013). The probability of occurrence P of each debris flow event is estimated using Eq. 9. In this application, the intensity is considered to be the velocity (in m/s) of an event. In this case, the intensity I is estimated using Eq. 11, given by [START_REF] Rickenmann | Empirical relationships for debris flows[END_REF].

P = 1/T (9) I = 2.1 • Q 0.33 p • S 0.33 (m/s) (10)
where S = 0.53 m/m is the average slope of the torrent's flow channel and Q p is the event's peak discharge. Q p can be estimated using the following equation, given by [START_REF] Rickenmann | Empirical relationships for debris flows[END_REF].

Q p = 0.1 •V 0.833 (m 3 /s) (11)
The damage rate curve is constructed according to Eq. 7. All data necessary for estimating the number of assets touched by debris flow events are assumed and presented in Table 1. The curve presenting the material losses is then implemented using Eq. 8, considering ε D = 0.1 and ε E = 0.1.

The obtained results are presented in Figure 3. The mean risk level, corresponding to the area under the curve presenting the material losses is R = 43.75 M C.

Presence of Protection System

In the case where a protection system is present in the torrent, the intensity of a debris flow event is reduced depending on the state of the system. As mentioned before, three deterioration states are considered. The threshold, defined in Section 3.1, corresponding to the technical efficacy level of the intermediate state of the protection system, is considered to be E 1 = 0.5. It is assumed that if the system is in state 1, the intensity will be reduced respectively by α 1 = 0.8. If the system is in state 2, the intensity will be reduced respectively by α 2 = 0.5. If the system is in state 3, the intensity will not be reduced and therefore will be equal to the intensity of the events in the case of the absence of a protection system. These reduction factors make it possible to estimate the intensity I 1 , I 2 and I corresponding to the cases when the system is respectively in state 1, 2 and 3 as shown in Figure 4. However, in all cases, the intensity will not be reduced if it exceeds I th = 13 m/s, as it is considered too strong for a protection system to handle. The damage rate in each case can be then estimated using Eq. 7. Finally, the material losses in each case are computed using Eq. 8 and presented in Figure 5.

Results provided in

Benefits: Reduction in Risk level

In order to construct the evolution of the risk level over time in the presence of a deteriorating protection system, the deterioration process should be first developed. It is assumed that the deterioration rates following an exponential distribution are λ 1-2 = 0.05 and λ 2-3 = 0.02. This means that the transition times from state 1 to state 2 and from state 2 to state 3 are T 1-2 = 20 years and T 2-3 = 50 years. Considering that the modeling takes place over a duration of 100 years means that the protection system resides 20 years in state 1, 50 years in state 2 and 30 years in state 3. These results make it possible to plot the evolution of the risk level over time as shown in Figure 6,a.

For estimating the economic benefits of a protection system, its cost of construction should be first defined. Let us assume a protection system composed of four check dams, in which the cost of construction of one dam is 250000 C. In this case the total cost of construction is C c = 1 M C. Consequently, the evolution of the economic benefits over time are estimated based on Section 3.3 and presented in Figure 6,b. It can be noticed that the benefits outweigh the costs over the long term. This reveals that the project of implementing the protection system is cost-effective.

CONCLUSION

Natural phenomena in mountains can have devastating effects on communities and infrastructures. It is therefore crucial to implement protection systems/structures in order to minimize the risk of damage and loss of life and to insure economic stability. Moreover, assessing the economic efficacy of protection systems is essential for supporting risk managers to make decisions that balances between costs and benefits of the protection strategy. From this study, it has been revealed that risk and cost-benefit analyses are useful tools to compare the sum of potential economic losses resulted from natural phenomena with the costs spent on the protection system over its lifetime. Future work in this area could include considering maintenance operations, which will affect the deteriora-tion process and therefore the evolution of risk level over the lifetime of the protection system. Maintenance costs and discount rates could be also considered in the cost-benefit analysis for more reliable evaluation of long-term cost-effectiveness in different time periods. Another avenue for future work could be to conduct a real-case study to validate the method and to provide real-world examples of its use.

Figure 1 :

 1 Figure 1: Torrential watershed and structural protection measures.

Figure 2 :

 2 Figure 2: Deterioration process of a protection system.

14th

  Figure 3: Results of risk analysis in the absence of a protection system. (a) hazard modeling; (b) number of assets touched by an event of a given probability; (c) damage rate; (d) material losses.

  Figure 5 make it possible to estimate the mean risk level induced by debris flows considering the different states of the protection system: R 1 = 38.72 M C, R 2 = 42.28 M C

Figure 4 :

 4 Figure 4: Hazard curve showing the intensity reduction depending on the state of the protection system.

Figure 5 :

 5 Figure 5: Results showing the reduction in the material losses depending on the state of the protection system. (e.g., for P = 0.01, N touched assets = 3483, L = 564 MC)

14th

  Figure 6: (a) Evolution of risk level in the absence and the presence of a protection system; (b) Evolution of economic benefits of the studied protection system.

  14th International Conference on Applications of Statistics and Probability in Civil Engineering, ICASP14Dublin, Ireland, July 9-13, 2023

Table 1 :

 1 Data necessary for estimating the number of assets touched by debris flow events.

14th International Conference on Applications of Statistics and Probability in Civil Engineering, ICASP14Dublin, Ireland, July 9-13, 2023

ACKNOWLEDGEMENTS

This work has been partially supported by MIAI@Grenoble Alpes, (ANR-19-P3IA-0003).


Alexandra Basilio Lopes

Patrick Wagner

Mickaël Choury

Mihaela Gulea
email: gulea@unistra.fr

Mickael Choury

Synthesis of new N/S-containing compounds by Pd-catalyzed tandem reactions

Keywords: nitrogen-sulfur heterocycles, medium-sized rings, palladium catalysis, desulfanylative coupling, hydrothiolation ( ) m ( ) m

come   L'archive ouverte pluridisciplinaire

INTRODUCTION

Compounds containing both nitrogen and sulfur atoms can be found in the structures of a broad range of drugs approved by the FDA. 1 Several are N,S-heterocycles with 5-, 6-, or 7-membered rings (e.g. Actosâ, Claforanâ, Seroquelâ), however no representatives of the medium-sized rings (8 to 11 atoms) are found among them. Increase the molecular diversity of this class is an important task for the discovery of new leads for pharmaceutic applications. In this context, recent work from our laboratory focused on the development of metal-catalyzed processes for the synthesis of original N,S-heterocycles, 2 and in particular those with challenging medium-sized rings. 2c-2e,3

Indeed, their access is known to be difficult because of the high degree of transannular strain and unfavorable entropic factors involved, in particular when the synthetic strategies are based on intramolecular carbon-carbon or carbon-heteroatom bond formation. In this context, our results obtained using Pd-catalyzed reactions are presented herein.

RESULTS AND DISCUSSION

Substrates 1 were used as the precursors of benzimidazole-fused medium-sized N,Sheterocycles. The benzimidazole moiety provides the advantage of its widespread occurrence in biologically active compounds and drugs (e.g. Nexiumâ). The synthetic strategy consisted in the intramolecular C-C bond formation through the Pd-catalyzed reductive cyclization (Scheme 1). 2c

Scheme 1. Synthesis of 8-and 9-membered ring N,S-heterocycles by reductive cyclocarbopalladation

We identified the following reaction conditions from the optimization study: Pd(PPh3)4 as the catalyst, ammonium formate as the hydrogen donor, DMF as the solvent, and a reaction temperature of 120 °C. Under these conditions, the desired 8-membered N,S-heterocycle 2a was obtained in 57% isolated yield (

N N S R 1 Br 1 ( ) n N N S R 1 Ph ( ) n ( ) m ( ) m ( ) m ( ) n (m, n = 0, 1) X X' X X' X X'
direct reduction of the substrate resulting in side-products 1H. The obtained heterocycles have an exocyclic double bond of which Z-geometry was controlled by the syn-carbopalladation. The mechanism of the Pd-catalyzed process is given in Scheme 2. Arylpalladium(II) species I1 led either to the hydrodebrominated side-product 1Ha, or to the cyclic alkenylpalladium(II) species I2 via an 8-exo-dig cyclization. The latter led to the corresponding thiazocine 2a after the following reductive process: bromide-to-formate ligand exchange with hydride transfer (to give I3) and formation of ammonium bromide and carbon dioxide, and final reductive elimination regenerating the Pd(0) catalytic species.

Scheme 2. Mechanism of the Pd-catalyzed processes to access thiazocine 2a.

We then attempted to access by this method larger rings (Scheme 3). Starting from 4, the reduced compound 4H was the major product (49% isolated yield). Two other products were formed in a 1:1 ratio and a combined yield of 24%, thiazecane 5 and E-thiazaundecene 6. This represents a rare example of competing processes between 10-exo and 11-endo cyclocarbopalladation of alkynes. 4 We have succeeded to crystallize thiazocine 2a, thiazonine 3c, and thiazaundecene 6, and confirmed their structures by X-ray diffraction analysis (Figure 1). Based on our previous work on the synthesis of 5-and 6-membered ring S-heterocycles via a cyclocarbopalladation/Suzuki-Miyaura coupling domino reaction, 5 we also attempted to apply this method to access benzothiazocines 7 (Scheme 4). The desired product 7q was obtained only in a small amount (8% isolated yield) along with several side products, and product 7r was isolated in low yield of 27%. 6

Scheme 4. Synthesis of 8-membered ring N,S-heterocycles by cyclocarbopalladation/Suzuki-Miyaura coupling

In the case of the transformation of 1q into 7q, we were able to isolate an unexpected side product 10q in 11% yield and determine its structure. We supposed that it was formed via a Pd-catalyzed tandem reaction consisting in a direct coupling leading to 8q, a desulfenylative coupling 7 giving 9q, then the hydrothiolation of the triple bond of the latter by the released thiolate 11 to finally give 10q (Scheme 5). Then, to study the scope of the reaction, we prepared other bromobenzylsulfenyl propargyl benzimidazoles 1 bearing the bromide in ortho, meta or para position and used various electronrich or electron-poor arylboronic acids as coupling partners (Table 2). The corresponding desired products 10 were obtained in satisfactory yields, up to 82%. 8 The mode of the hydrothiolation, intramolecular versus intermolecular, was also examined by a crossover experiment with a equimolar mixture of substrates 12a and 12b (Scheme 7). At the end of the reaction, the analysis of the resulting crude mixture (by 1 H NMR and HRMS) clearly showed only the presence of products 13a and 13b (in a 1:1 ratio) [START_REF]Experimental procedure: To a sealed tube containing a mixture of substrates 12a (0.5 equiv) and 12b (0.5 equiv), phenyl boronic acid (3.0 equiv), K2CO3 (3.0 equiv), Pd2(dba)3 (5 mol%) and PCy3 (20 mol%), was added as the solvent a mixture of 1,4-dioxane/water[END_REF] and no traces of cross-products 13ab

or 13ba. This result showed that the hydrothiolation occurs intramolecularly.

Scheme 3 .Figure 1 .

 31 Scheme 3. Extension to larger rings: 10-exo vs 11-endo-dig cyclisation

Scheme 5 .

 5 Scheme 5. Pd-catalyzed reaction of benzimidazole 1q with phenyl boronic acid; supposed reaction course

Scheme 7 .

 7 Scheme 7. Crossover experiment

Table 1

 1

	, entry 1). The scope and limitations have been established

Table 1 .

 1 Obtained 8-and 9-membered ring N,S-heterocycles 2 and 3

	Entry Ring size	m, n	R 1	X, X'	Product	Yield (%)
	1	8	1, 0	Et	H, H	2a	57
	2	8	1, 0	Ph	H, H	2b	53
	3	8	1, 0	CH2OH	H, H	2c	27
	4	8	1, 0	4-MeO-C6H4 H, H	2d	47
	5	8	1, 0	4-Me-C6H4	H, H	2e	51
	6	8	1, 0	4-CF3-C6H4	OMe, H	2f	37
	7	8	1, 0	3-F-C6H4	H, OMe	2g	40
	8	8	1, 0	3-Thienyl	H, H	2h	37
	9	8	1, 0	H	H, H	2i	not isolated
	10	8	1, 0	Et	OMe, H	2j	55
	11	8	1, 0	Et	H, OMe	2k	53
	12	8	1, 0	Ph	OMe, H	2l	49
	13	8	1, 0	Ph	H, OMe	2m	38
	14	8	1, 0	Et	Cl, H	2n	52
	15	8	1, 0	Et	H, Cl	2o	32
	16	8	1, 0	Et	Me, Me	2p	42
	17	8	0, 1	Et	H, H	2q	18
	18	9	1, 1	Et	H, H	3a	46
	19	9	1, 1	Ph	H, H	3b	45
	20 *	9	1, 1	Et	H, H	3c	38
	21	9	1, 1	Et	Me, Me	3d	40

* In the structure of the precursor 1, 2-Br-5-OMe-C6H3 was used instead 2-Br-C6H4

Table 2 .

 2 Tandem reaction of various substrates 1 with aryl boronic acids.

			Et	R			Et		S
		N N	S 1	Br	reaction conditions ArB(OH) 2 [Pd]	N N	Ar	Ar	10	R
	Reaction conditions: boronic acid (3 equiv), Pd 2 (dba) 3 (5 mol%), PCy 3 (20 mol%), K 2 CO 3 (3 equiv), dioxane/H 2 O 4/1 (0.1 M), 130 °C, 19 h.
	Entry Br-position R		Ar	Yield (%)
	1	2-Br	H		Ph	66
	2	3-Br	H		Ph	70
	3	4-Br	H		Ph	82
	4	4-Br	H		4-MeO-C6H4	62
	5	4-Br	H		4-CF3O-C6H4	64
	6	4-Br	H		4-F-C6H4	57
	7	4-Br	H		4-CF3-C6H4	46
	8	3-Br	H		3-NO2-C6H4	18
	9	3-Br	H		3-CF3-C6H4	66
	10	3-Br	H		3-MeO-C6H4	74
	11	2-Br	OMe	Ph	42
	12	2-Br	OMe	4-MeO-C6H4	56
	13	2-Br	OMe	4-F-C6H4	43
	Starting from substrate 12a without Br, the reaction still worked, leading to 13a (Scheme 6). From
	substrate 14 with methyl instead propargyl, the desulfanylative coupling product 15 was not
	obtained, suggesting that the triple bond is ideally placed to coordinate the Pd-thiolate species,
	facilitating the desulfanylation and the hydrothiolation. Indeed, the desulfenylative coupling

ACKNOWLEDGMENTS

We thank the MESRI for the doctoral grant for M.C., the University of Strasbourg for the postdoctoral IdEx grant for A.B.L., and the CNRS for recurrent financial support. We thank Dr. D. Garnier and E. Oliva (PACSI, No. GDS 3670) for NMR and mass analyses.

Graphic for Table of Contents

Synthesis of new N/S-containing compounds by Pd-catalyzed tandem reactions

Alexandra Basilio Lopes, Patrick Wagner, Mickael Choury, and Mihaela Gulea*