7 Search Results for "Koehler, Jana"


Document
Invited Talk
Beyond Optimal Solutions for Real-World Problems (Invited Talk)

Authors: Maria Garcia de la Banda

Published in: LIPIcs, Volume 280, 29th International Conference on Principles and Practice of Constraint Programming (CP 2023)


Abstract
Combinatorial optimisation technology has come a long way. We now have mature high-level modelling languages in which to specify a model of the particular problem of interest [Nethercote et al., 2007; Frisch et al., 2008; Van Hentenryck, 1999; Fourer et al., 1990]; robust complete solvers in each major constraint paradigm, including Constraint Programming (CP), MaxSAT [Jessica Davies and Fahiem Bacchus, 2011; Alexey Ignatiev et al., 2019], and Mixed Integer Programming (MIP); effective incomplete search techniques that can easily be combined with complete solvers to speed up the search such as Large Neighbourhood Search [Paul Shaw, 1998]; and enough general knowledge about modelling techniques to understand the need for our models to incorporate components such as global constraints [Willem-Jan van Hoeve and Irit Katriel, 2006], symmetry constraints [Ian P. Gent et al., 2006], and more. All this has significantly reduced the amount of knowledge required to apply this technology successfully to the many different combinatorial optimisation problems that permeate our society. And yet, not many organisations use such advanced optimisation technology; instead, they often rely on the solutions provided by problem-specific algorithms that are implemented in traditional imperative languages and lack any of the above advances. Further, while advanced optimisation technology is particularly suitable for the kind of complex human-in-the-loop decision-making problems that occur in critical sectors of our society, including health, transport, energy, disaster management, environment and finance, these decisions are often still made by people with little or no technological support. In this extended abstract I argue that to change this state of affairs, our research focus needs to change from improving the technology on its own, to improving it so that users can better trust, use, and maintain the optimisation systems that we develop with it. The rest of this extended abstract discusses my personal experiences and opinion on these three points. Trust I highlight trust (which focuses on the user’s point of view) rather than trustworthiness (which is a characteristic of the software itself) because I think it is the former rather than the latter that is at stake for the adoption of optimisation technology. One of the biggest hurdles I have found for trust in the context of optimisation systems is for the domain experts to (feel like they) understand the underlying model. While many users will never do (or have to), I believe it is key for domain experts to have a high-level understanding of the constraints in the model, since their (dis)trust will likely spread through the organisation, impacting the adoption of the system. Thanks to the use of high-level modelling languages in CP, our group has achieved this [Matthias Klapperstueck et al., 2023] by documenting the constraints in a language the user knows (mathematics) and linking each constraint to the particular part of the model that implements it (via comments). While domain experts do not completely understand the model, the similarity between the format they understand (mathematics) and the model constraint has helped them verify our perception of their problem and improved their trust in the model. However, more needs to be done in this direction via the development of formal techniques. For example, our group is exploring the use of domain-specific languages [Hudak, 1997] as a bridge between domain experts and modellers that helps both trust and maintenance (see later). This [Sameela Suharshani Wijesundara et al., 2023] and other approaches need to be explored. A very significant source of trust for our domain experts (and of trustworthiness for the software) has been the development of two different models implemented by two different people for the same problem [Matthias Klapperstueck et al., 2023]. While this can be seen as a prohibitively expensive exercise, it did not take that long once the first model was mature, is a good way to onboard new optimisation team members, and has helped up detect not only bugs but also differences in the interpretation of domain expert information. For optimisation problems where it is not possible to verify the optimality (or even correctness) of the solution, we see such redundant modelling as the only solution for now. Interestingly, a significant step forward in obtaining the trust of our domain experts has been the generation of an optimality gap whenever an optimal solution could not be found due to time constraints. While explaining this concept took time, once understood it has boosted their trust, particularly when tackling problems where the solution is not easy verifiable or when approximated models/data are used (needed for speed, see later). This makes it difficult to work with CP and SAT solvers, as they usually lack tight lower bounds. Finally, trust is often developed through the use of the system, which I discuss below. Use Usability is known to be key for the deployment of software systems. By "system" in our context, I refer to the combination of the problem model(s), the associated solver(s) and, importantly, the User Interface (UI) that often integrates them and is fundamental to their success. In addition to the traditional usability characteristics of software systems, I believe an optimisation system requires particular care in the following areas. Interaction, i.e., the system must allow users to interact with the UI not only to provide and modify the input data, but also to modify the constraints (at the very least by turning some on/off) as well as explore and compare solutions, as argued in [David Meignan et al., 2015; Jie Liu et al., 2021]. Incremental compilers and solvers would significantly help in making this easier, as well as generic ways for the UIs to communicate with them. Conflict resolution, that is, ensuring the system can not only detect infeasible instances, but also support users in understanding the data/constraints that cause infeasibility and how to modify the instance to make it feasible. Any interactive optimisation system that has users, will likely have conflicts. Thus, it is mandatory for CP to improve its conflict resolution technology which, while existent [João Marques-Silva and Alessandro Previti, 2014; Lauffer and Topcu, 2019; Ilankaikone Senthooran et al., 2023], is not widespread and it is often still problem-dependent, overwhelming (in the number of constraints shown to the user) and slow. Without it, users will be "stumped" when (rather than if) infeasibility is reached. Solution diversity, that is, supporting users in obtaining a diverse set of (close-to-optimal) solutions, where diversity is measured by a user-provided metric modelled somehow. While some solver-independent technology has been developed and implemented for this [Emmanuel Hebrard et al., 2005; Thierry Petit and Andrew C. Trapp, 2015; Linnea Ingmar et al., 2020], it should be easier to use and more widespread. Further, it requires sophisticated solution comparison capabilities and, importantly, for optimal solutions to be found in seconds rather than hours. This brings me to speed, an area where CP solvers are falling behind. Most of our research group applications now use MIP solvers due to the need for floats (which precludes us from using learning solvers such as Chuffed [Geoffrey Chu, 2013]), but also to the lack of effective warm-start processes that are available in MIP solvers. Interestingly, data and model approximations have been proved to achieve orders of magnitude speedups with small reductions in optimality [Matthias Klapperstueck et al., 2023]. Developing generic (i.e., problem independent) accurate approximations would be extremely useful for complex decision systems. Other areas where I think generic CP methods are worth investigating more include dealing with uncertainty and online problems, ensuring solution fairness (even if it is over time), and studying predict + optimise approaches. Maintain I know very few papers devoted to the issue of maintenance in optimisation technology. While this may be due to my lack of knowledge, I suspect it is also due to the limited adoption of optimisation technology. While the issues in this area are again common to other software systems, I believe the solutions for CP require special attention. For example, the issue of changes in user requirements (that our research group calls problem drift) seems particularly prevalent in decision-making systems, as such problems can evolve rapidly due to unforeseen circumstances. This can make optimisation systems obsolete faster than expected. Our research group has proposed to tackle problem drift by developing a requirements model implemented in the above-mentioned MDSLs and created by both domain experts and modellers that, when modified re-generates parts of the model to support the modifications [Sameela Suharshani Wijesundara et al., 2023]. This and other approaches such as the creation of reusable models components [Sophia Saller and Jana Koehler, 2022; Toby Walsh, 2003], or instantiatable classes for common problem domains, are worth investigating.

Cite as

Maria Garcia de la Banda. Beyond Optimal Solutions for Real-World Problems (Invited Talk). In 29th International Conference on Principles and Practice of Constraint Programming (CP 2023). Leibniz International Proceedings in Informatics (LIPIcs), Volume 280, pp. 1:1-1:4, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)


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@InProceedings{garciadelabanda:LIPIcs.CP.2023.1,
  author =	{Garcia de la Banda, Maria},
  title =	{{Beyond Optimal Solutions for Real-World Problems}},
  booktitle =	{29th International Conference on Principles and Practice of Constraint Programming (CP 2023)},
  pages =	{1:1--1:4},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-300-3},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{280},
  editor =	{Yap, Roland H. C.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2023.1},
  URN =		{urn:nbn:de:0030-drops-190384},
  doi =		{10.4230/LIPIcs.CP.2023.1},
  annote =	{Keywords: Combinatorial optimisation systems, usability, trust, maintenance}
}
Document
07061 Abstracts Collection – Autonomous and Adaptive Web Services

Authors: Jana Koehler, Marco Pistore, Amit P. Sheth, Paolo Traverso, and Martin Wirsing

Published in: Dagstuhl Seminar Proceedings, Volume 7061, Autonomous and Adaptive Web Services (2007)


Abstract
From 4.2.2007 to 9.2.2007, the Dagstuhl Seminar 07061 ``Autonomous and Adaptive Web Services'' was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available.

Cite as

Jana Koehler, Marco Pistore, Amit P. Sheth, Paolo Traverso, and Martin Wirsing. 07061 Abstracts Collection – Autonomous and Adaptive Web Services. In Autonomous and Adaptive Web Services. Dagstuhl Seminar Proceedings, Volume 7061, pp. 1-22, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)


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@InProceedings{koehler_et_al:DagSemProc.07061.1,
  author =	{Koehler, Jana and Pistore, Marco and Sheth, Amit P. and Traverso, Paolo and Wirsing, Martin},
  title =	{{07061 Abstracts Collection – Autonomous and Adaptive Web Services}},
  booktitle =	{Autonomous and Adaptive Web Services},
  pages =	{1--22},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2007},
  volume =	{7061},
  editor =	{Jana Koehler and Marco Pistore and Amit P. Sheth and Paolo Traverso and Martin Wirsing},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.07061.1},
  URN =		{urn:nbn:de:0030-drops-10359},
  doi =		{10.4230/DagSemProc.07061.1},
  annote =	{Keywords: Intelligent Web Services and Semantic Web, Software Architectures, Distributed Systems, Program Verification, Interoperability}
}
Document
ASG - Techniques of Adaptivity

Authors: Harald Meyer, Dominik Kuropka, and Peter Tröger

Published in: Dagstuhl Seminar Proceedings, Volume 7061, Autonomous and Adaptive Web Services (2007)


Abstract
The introduction of service-orientation leads to significant improvements regarding flexibility in the choice of business partners and IT-systems. This requires an increased adaptability of enterprise software landscapes as the environment is more dynamic than the ones in traditional approaches. In this paper we present different types of adaptation scenarios for service compositions and their implementation in a service provision platform. Based on experiences from the Adaptive Services Grid (ASG) project, we show how dynamic adaptation strategies are able to support an automated selection, composition and binding of services during run-time.

Cite as

Harald Meyer, Dominik Kuropka, and Peter Tröger. ASG - Techniques of Adaptivity. In Autonomous and Adaptive Web Services. Dagstuhl Seminar Proceedings, Volume 7061, pp. 1-19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)


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@InProceedings{meyer_et_al:DagSemProc.07061.2,
  author =	{Meyer, Harald and Kuropka, Dominik and Tr\"{o}ger, Peter},
  title =	{{ASG - Techniques of Adaptivity}},
  booktitle =	{Autonomous and Adaptive Web Services},
  pages =	{1--19},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2007},
  volume =	{7061},
  editor =	{Jana Koehler and Marco Pistore and Amit P. Sheth and Paolo Traverso and Martin Wirsing},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.07061.2},
  URN =		{urn:nbn:de:0030-drops-10361},
  doi =		{10.4230/DagSemProc.07061.2},
  annote =	{Keywords: Adaptive service provision, service selection, automated service composition, service recovery}
}
Document
Composing Web-service-like abstract state machines (ASM)

Authors: Andreas Friesen and Lemcke Jens

Published in: Dagstuhl Seminar Proceedings, Volume 7061, Autonomous and Adaptive Web Services (2007)


Abstract
The presentation provides an overview on semi-automatic design of Collaborative Business Processes for B2B/EAI integration in the EU project FUSION. The introduced Enterprise Application Integration Ontology and a mediator-based run-time architecture for CBPs integrating heterogeneous web services enabled enterprise systems build the corner stones of the FUSION solution. The functionality and the building blocks of the Collaborative Business Process Designer are discussed in detail. The talk provides then an example demonstrating initial ideas for generating an executable collaborative business process out of a CBP template automatically.

Cite as

Andreas Friesen and Lemcke Jens. Composing Web-service-like abstract state machines (ASM). In Autonomous and Adaptive Web Services. Dagstuhl Seminar Proceedings, Volume 7061, pp. 1-30, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)


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@InProceedings{friesen_et_al:DagSemProc.07061.3,
  author =	{Friesen, Andreas and Lemcke Jens},
  title =	{{Composing Web-service-like abstract state machines (ASM)}},
  booktitle =	{Autonomous and Adaptive Web Services},
  pages =	{1--30},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2007},
  volume =	{7061},
  editor =	{Jana Koehler and Marco Pistore and Amit P. Sheth and Paolo Traverso and Martin Wirsing},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.07061.3},
  URN =		{urn:nbn:de:0030-drops-10348},
  doi =		{10.4230/DagSemProc.07061.3},
  annote =	{Keywords: Business process composition, collaborative business processes, Web service composition, enterprise application integration, business-to-business inte}
}
Document
Role of semantics in Autonomic and Adaptive Web Services & Processes

Authors: Amit P. Sheth

Published in: Dagstuhl Seminar Proceedings, Volume 7061, Autonomous and Adaptive Web Services (2007)


Abstract
The emergence of Service Oriented Architectures (SOA) has created a new paradigm of loosely coupled distributed systems. In the METEOR-S project, we have studied the comprehensive role of semantics in all stages of the life cycle of service and process-- including annotation, publication, discovery, interoperability/data mediation, and composition. In 2002-2003, we had offered a broad framework of semantics consisting of four types:1) Data semantics, 2) Functional semantics, 3) Non-Functional semantics and 4) Execution semantics. This talk describes the need for the four types of semantics, its standards-based support through WSDL-S/SAWSDL, and the need for such semantic representation to dynamic and adaptive SOA. We also briefly review the proposal for Adaptive Web Processes introduced earlier in a ICSOC 2005 vision talk.

Cite as

Amit P. Sheth. Role of semantics in Autonomic and Adaptive Web Services & Processes. In Autonomous and Adaptive Web Services. Dagstuhl Seminar Proceedings, Volume 7061, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)


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@InProceedings{sheth:DagSemProc.07061.4,
  author =	{Sheth, Amit P.},
  title =	{{Role of semantics in Autonomic and Adaptive Web Services \& Processes}},
  booktitle =	{Autonomous and Adaptive Web Services},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2007},
  volume =	{7061},
  editor =	{Jana Koehler and Marco Pistore and Amit P. Sheth and Paolo Traverso and Martin Wirsing},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.07061.4},
  URN =		{urn:nbn:de:0030-drops-10325},
  doi =		{10.4230/DagSemProc.07061.4},
  annote =	{Keywords: Adaptive web service, autonomic web service, adaptive web process, autonomic web process, data semantics, functional semantics, non-functional semanti}
}
Document
Towards Analyzing Declarative Workflows

Authors: Dirk Fahland

Published in: Dagstuhl Seminar Proceedings, Volume 7061, Autonomous and Adaptive Web Services (2007)


Abstract
Enacting tasks in a workflow cannot always follow a pre-defined process model. In application domains like disaster management workflows are partially specified and circumstances of their enactment change. There exist various approaches for formal workflow models that are effective in such situations, like declarative specifications instead of operational models for formalizing flexible workflow process. These powerful models leave a gap to existing techniques in the domain of workflow modeling, workflow analysis, and workflow management. In this paper we bridge this gap with a compositional mechanism for translating declarative workflow models to operational workflow models. The mechanism is of a general nature and we reveal its principles as we provide an exemplary definition for translating DecSerFlow models based on LTL to Petri nets. We then demonstrate its use in analyzing and refining declarative models.

Cite as

Dirk Fahland. Towards Analyzing Declarative Workflows. In Autonomous and Adaptive Web Services. Dagstuhl Seminar Proceedings, Volume 7061, pp. 1-20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2007)


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@InProceedings{fahland:DagSemProc.07061.5,
  author =	{Fahland, Dirk},
  title =	{{Towards Analyzing Declarative Workflows}},
  booktitle =	{Autonomous and Adaptive Web Services},
  pages =	{1--20},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2007},
  volume =	{7061},
  editor =	{Jana Koehler and Marco Pistore and Amit P. Sheth and Paolo Traverso and Martin Wirsing},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.07061.5},
  URN =		{urn:nbn:de:0030-drops-10332},
  doi =		{10.4230/DagSemProc.07061.5},
  annote =	{Keywords: Workflow, declarative, temporal logic, flexible, adaptive, analysis, transformation, Petri net}
}
Document
Control of Search in AI Planning (Dagstuhl Seminar 9647)

Authors: Jim Hendler and Jana Koehler

Published in: Dagstuhl Seminar Reports. Dagstuhl Seminar Reports, Volume 1 (2021)


Abstract

Cite as

Jim Hendler and Jana Koehler. Control of Search in AI Planning (Dagstuhl Seminar 9647). Dagstuhl Seminar Report 161, pp. 1-21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (1997)


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@TechReport{hendler_et_al:DagSemRep.161,
  author =	{Hendler, Jim and Koehler, Jana},
  title =	{{Control of Search in AI Planning (Dagstuhl Seminar 9647)}},
  pages =	{1--21},
  ISSN =	{1619-0203},
  year =	{1997},
  type = 	{Dagstuhl Seminar Report},
  number =	{161},
  institution =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemRep.161},
  URN =		{urn:nbn:de:0030-drops-150482},
  doi =		{10.4230/DagSemRep.161},
}
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