Soon Ae Chun: Research Overview

With the rapid growth of Internet applications for enterprise-wide and cross-enterprise business processes with dynamically changing participants, workflow management sys- tems (WFMS) face various challenges: (1) cross-organizational workflow design and definition need to be dynamic, efficiently constructed, and customized to a user's needs; (2) workflow execution should honor the autonomy of various participating organiza- tions, avoiding centralized control which can be a potential bottleneck and single point of failure, and (3) service and business workflows should be customizable at run time to adapt to changes of requirements and exception situations. This project has contributed to the progress towards the formalization and development of a decentral- ized workflow system that supports customized workflows that can be automatically composed at design time, and that adds greater flexibility for dynamic workflows that can adapt to the changing requirements and environments. This research also has contributed to the progress towards the understanding of requirements and limitations in developing inter-agency E-government application systems.

1. Decentralized Workflow Model:
   The issues of autonomy and scalability are addressed with the decentralized workflow management model that enforces intertask dependencies without the need for a centralized WFMS. The model utilizes self-describing workflows, workflow partitions that carry sufficient information so that they can be managed by a local task execution agent rather than the central WFMS, and WFMS stubs, light-weight agent attached to a task execution agency, that is responsible for receiving the self-describing workflow, processing and dynamically partitioning the workflow.
   
   
2. Conflict-of-Interests in Inter-organizational Workflow (Chinese Wall Security)
   This project identifies conflict-of-interest problems that may arise in decentralized control of the inter-organizational workflows, where a task agent may take advantage of others by manipulating the semantics of the workflow. This project proposes a decentralized workflow Chinese Wall Security model that supports fair execution of a workflow in a decentralized manner with sensitive data, the conflict-of-interest groups, restrictive partitioning and secure dependency splitting algorithms.
   
   
3. Ontology-based Workflow Generation
   To support automatic on-the-fly composition of customized inter-organizational workflows, this project develops an ontology-based dynamic workflow generation model. This model utilizes a conceptual ontology of component services (tasks), a topic ontology of domain composition knowledge that hierarchically structures workflow com- position rules according to the given topic concepts, and user profile.
   
   
4. Dynamic Worflow Change Management
   To handle run-time changes and exceptions for a flexible workflow system, this thesis provides a dynamic change management model that allows the specification of a change request with controlled vocabulary derived from concepts in an ontology, the context manager that monitors changes in the user profiles, rules, and exceptions, and the ontology-based identification of migration rules requisite to adapt to changes. The modified workflow is ensured to be migration consistent to the original workflow and its execution states.
   
   
5. Performance Analysis of Decentralized Workflow Model
   We are also conducting the performance studies to contrast the proposed decentralized workflow execution model with the centralized architecture. Specifically, the performance advantages gained in the minimal (need-based) evaluation of dependency conditions and JOIN and SPLIT relations in different workflow cases.
   
   
6. Related Projects

1. Knowledge-based Personalized Web Service Composition
2. Policy-based Web Service Composition (with V. Atluri and N. Adam, 2003-date)
3. Ontology and pragmatic Knowlege for Semantic Web (with Y. Lee and J. Geller, 2003-date)
4. Context Model for Pervasive Semantic Web Services (with Y. Lee and J. Geller, 2003-date)
5. Related projects

1. Geospatial data Authorization Model:
   The advent of commercial observation satellites in the new millennium provides unprecedented access to timely information, as they produce images of the Earth with the sharpness and quality previously available only from U.S., Russian, and French military satellites. Due to the fact that they are commercial in nature, a broad range of government agencies (including international), the news media, businesses and non-governmental organizations can gain access to this information. This may have grave implications on national security and personal privacy. Formal policies for prohibiting the release of imagery beyond a certain resolution, and notifying when an image crosses an international boundary or when such a request is made, are beginning to emerge. Access permissions in this environment are determined by both the spatial and temporal attributes of the data, such as location, resolution level and the time of image download, as well as those of the user credentials. Since existing authorization models are not adequate to provide access control based on spatial and temporal attributes, in this paper, we propose a Geospatial Data Authorization Model (GSAM). Unlike the traditional access control models where authorizations are specified using subjects and objects, authorizations in GSAM are specified using credential expressions and object expressions. GSAM supports privilege modes including view, zoom-in, download, overlay, identify, animate and fly-by, among others. We present our access control prototype system that enables subject, object as well as authorization specification via a web-based interface. When an access request is made, the access control system computes the overlapping region of the authorization and the access request. The zoom-in and zoom-out requests can simply be made through a click of the mouse, and the appropriate authorizations will be evaluated when these access requests are made.
   
   
2. Related Project
3. Chinese Wall Security Model for Decentralized Workflow Management:
   Decentralized execution of inter-organizational workflows may raise a number of security issues including those related to conflict-of-interest among competing organizations. In this paper, we first provide an approach to realize decentralized workflow execution, in which the workflow is divided into partitions, called self-describing workflows, and handled by a light weight workflow management component, called workflow stub, located at each organizational agent. Second, we identify the limitations of the traditional workflow model with respect to expressing the various types of join dependencies and extend the traditional workflow model suitably. Distinguishing the different types of dependencies among tasks is essential in the efficient execution of self-describing workflows. Finally, we recognize that placing the task execution agents that belong to the same conflictof- interest class in one self-describing workflow may lead to unfair, and in some cases, undesirable results, akin to being on the wrong side of the Chinese wall. Therefore, to address the conflict-of-interest issues that arise in competitive business environments, we propose a decentralized workflow Chinese wall security model. We propose a restrictive partitioning solution to enforce the proposed model.
   
   

1. Environmental Data management:
   Environmental decision making is a complex process that requires fusing of diverse data, including environmental and non-environmental (e.g. locational, parcel) information, to meet speicific goals. I am investigating two basic components in various decision making processes for environmental management in New Jersey Meadowlands area: data fusing and explanation process modeling and integration. This work is conducted in collaboration with MERI (Meadowlands Environmental Research Instiutute) at NJMC.
   
   
2. Data Management and Integration
   Hosts of data collected and being collected continuously are available but not integrated or interoperable for useful information and knowledge. Basic problem of locating the right set of data to create knowledge for a specific purpose and delivering in an intuitive format is crucial for decision making. The data identification, customization, integration and visualization are primary tasks.
   
   
3. Process modeling and integration:
   Various tasks and services are being performed as stand-alone, independent module. The coherent service and task requires composition and integration of various services and tasks. Toward this end, the process modeling is required. In order to model process, there are basic knowledge of how tasks are integrated. This knowledge modeling may be standard operational procedures or implicit in experts tasks. My research goal is to capture this process knowledge and model it for machine processable format for automatic process composition.
   
   
4. Application processes Process modeling may be specific to particular applications. We are actively identifying meaningful decision making applications for various stateholders of the Meadowlands area, including environmental planners, researchers/scientists, citizens.
   
   
5. Mobile Environmental Information System (m-ENVI) In environmental agencies, like NJMC, engineers use mobile devices, as they move around the field to collect data. In addition, they host visitors, scientists, government officials, students and eco-tourist participants, in and around Meadowlands areas for different purposes, from simple strolling to learning about the nature or landscapes to scientific investigations to managerial decision making, etc. Currently, the visual observation or guided tour by NJMC and affiliated staff is used. We propose to build a mobile communication infrastructure to enable the auto-guided environmental tour information system for these participants. Each visitor or staff will be given a mobile device. Based on the location, the current and historical environmental information available at the location is delivered. The information type can be adjusted according to the user's preferences, e.g. a field engineer may be more interested in the historical data on the land use for the particular site, while a student may be more interested in learning about the habitats in the particular location he is standing. As in the museum tour guide system, the relevant information is identified and streamed based on the person's location and preference and expertise. Unlike the museum tour guide system, the information is not restricted to audio. Information can be multimedia, including images/pictures, maps, textual narratives, audio and others. In addition, the users can interactively enter the new data observed and collected from the location into the system for the future information sharing. It allows a location-specific environmental information blogging. It also supports data "pull", allowing queries by users of different levels and expertise.
   
   

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