DAS: Intelligent Scheduling Systems for Shipbuilding

Lee, J. K., Lee, K. J., Hong, J. S., Kim, W. J., Kim, E. Y., Choi, S. Y., Kim, H. D., Yang, O. R., Choi, H. R., “DAS: Intelligent Scheduling Systems for Shipbuilding”, AI Magazine, vol. 16, no. 2, pp. 78-94, Winter, 1995.pdf


Daewoo Shipbuilding Company, one of the largest shipbuilders in the world, has experienced a great deal of trouble with the planning and scheduling of its production process. To solve the problems, from 1991 to 1993, Korea Advanced Institute of Science and Technology (KAIST) and Daewoo jointly conducted the Daewoo Shipbuilding Scheduling (das) Project. To integrate the scheduling expert systems for shipbuilding, we used a hierarchical scheduling architecture. To automate the dynamic spatial layout of objects in various areas of the shipyard, we developed spatial scheduling expert systems. For reliable estimation of person-hour requirements, we implemented the neural network–based person-hour estimator. In addition, we developed the paneledblock assembly shop scheduler and the longrange production planner. For this large-scale project, we devised a phased development strategy consisting of three phases: (1) vision revelation, (2) data-dependent realization, and (3) prospective enhancement. The DAS systems were successfully launched in January 1994 and are actively being used as indispensable systems in the shipyard, resulting in significant improvement in productivity and visible and positive effects in many areas.

A Spatial Scheduling System and its Application to Shipbuilding: DAS-CURVE

Lee, K. J., J. K. Lee, S. Y. Choi, “A Spatial Scheduling System and its Application to Shipbuilding: DAS-CURVE”, Expert Systems with Applications, vol. 10, no.3/4 , pp. 311-324, 1996.pdf


Spatial scheduling considers not only traditional scheduling constraints like resource capacity and due dates, but also dynamic spatial layout of the objects. Automation of spatial scheduling is particularly important when the spatial resources are critical bottleneck resources, as is the case in the shipbuilding industry. To develop a spatial scheduling expert system for shipbuilding, a methodology for spatial layout of polygonal objects within rectangular plates is first developed. This study is then extended to the methodology for spatial scheduling, including the time dimension. The methodology is applied to the scheduling of Daewoo shipbuilding to build a system DAS-CURVE. DAS-CURVE is successfully operational and its experimental performance is remarkable.

Developing Scheduling Systems for Daewoo Shipbuilding: DAS Project

Lee, J. K., Lee, K. J., Park, H. K., Hong, J. S., Lee, J. S., “Developing Scheduling Systems for Daewoo Shipbuilding: DAS Project”, European Journal of Operational Research, vol. 97, no.2, pp.380-395, 1997.pdf


Daewoo Shipbuilding Company, one of the largest shipbuilders in the world, had difficulties with planning and scheduling its production process. To solve the problems, Korea Advanced Institute of Science and Technology (KAIST) and Daewoo have been jointly performing the DAS (DAewoo Shipbuilding Scheduling) Project for three years from 1991 to 1993. To develop the integrated scheduling systems, several technological breakthroughs were necessary such as hierarchical architecture between systems, constraint directed graph search, spatial scheduling, dynamic assembly line scheduling, and neural network based man-hours estimation. Besides these technological research issues, we adopted the phased development strategy, which consists of three phases of vision revelation, data dependent realization, and prospective enhancement. The DAS systems were successfully launched in January 1994 and are being actively used as indispensable systems in the shipyard resulting in a significant improvement in productivity and reengineering of the scheduling process.


Scheduling, Manufacturing Industries, Artificial Intelligence, Shipbuilding.

FASTrak-APT: Case and Constraint-Based Construction Project Planning System

Lee, K. J., Kim, H. W., Lee, J. K. Kim, T. H., “FASTrak-APT: Case and Constraint-Based Construction Project Planning System”, AI Magazine, vol.19, no.1, pp.13-24, Spring, 1998.pdf


To effectively generate a fast and consistent apartment construction project network, Hyundai Engineering and Construction and Korea Advanced Institute of Science and Technology developed a case- and constraint-based project-planning expert system for an apartment domain. The system, FASTRAK- APT, is inspired by the use of previous cases by a human expert project planner for planning a new project and the modification of these cases by the project planner using his/her knowledge of domain constraints. This large-scale, case-based, and mixed-initiative planning system, integrated with intensive constraint-based adaptation, utilizes semantic-level metaconstraints and human decisions for compensating incomplete cases imbedding specific planning knowledge. The case- and constraint-based architecture inherently supports cross-checking cases with constraints during system development and maintenance. This system has drastically reduced the time and effort required for initial project planning, improved the quality and completeness of the generated plans, and is expected to give the company the competitive advantage in contract bids for new contracts.

Sufficient Search Space in Spatial Expert Systems

Lee, K. J., “Sufficient Search Space in Spatial Expert Systems”, Expert Systems with Applications, vol. 19, no. 1, pp.1-8, July, 2000.pdf


This paper seeks the sufficient search space for the expert systems locating rectangular and arbitrary-shaped objects placed without rotation within a two-dimensional rectangular space. We found that for the layout of rectangular objects, the convex vertex set of feasible allocation space is a sufficient space to determine a feasible layout. We also found that for the layout of arbitrary-shaped objects, the boundary point set of the feasible allocation space is a sufficient space to determine a feasible layout. These two theorems are proved by developing two respective parallel translation algorithms. These theorems show that the search space can be significantly reduced in finding a feasible layout. Since these theorems were discovered while we were developing a spatial scheduling expert system, we have empirically tested the performance of the reduced search space with real world examples. According to the empirical test for the convex polygonal objects, the vertex set of feasible allocation space is satisfactory enough as a search space although the vertex set is not a sufficient space.

Customized Purchase Supporting Expert System: UNIK-SES

Lee, S. K., Lee, J. K. K. J. Lee, “Customized Purchase Supporting Expert System: UNIK-SES”, Expert Systems with Applications, vol. 11, no. 4, pp.431-441, 1996.pdf


An expert system that assists the customized men’s wear purchasing process is developed. In the past, configuration systems have adopted either a rule- or a constraint-based representation. To overcome the limitation of the representation, an integrated representation of the Constraint and Rule Satisfaction Problems (CRSP) is adopted. Since the general purpose tool UNIK-CRSP provides concurrent, integrated and interactive reasoning, UNIK-CRSP is very suitable for assisting the personalized customer product configuration process in a natural manner. Using UNIK-CRSP, the domain-specific tool UNIK-SES is developed with the additional features of candidate products selection and user interfaces. This approach should be useful for customer support in electronic marketing on the information superhighway.

Time-Bounded Negotiation Framework for Electronic Commerce Agents

Lee, K. J., Chang, Y. S., Lee, J. K., “Time-Bounded Negotiation Framework for Electronic Commerce Agents”, Decision Support Systems, vol. 28, no.4, pp. 319-331, June, 2000.pdf


For efficient and informative coordination of agents especially in electronic commerce environment, a time-bound agent negotiation framework is proposed utilizing a time-based commitment scheme. By attaching commitment duration to agent messages, the traditional contract net protocol is extended to a time-bound negotiation framework TBNF. The proposed negotiation framework has a new message type which allows for parties to agree upon the extension of commitment duration, and a novel commitment concept in the form of negative commitment. The semantics of the messages with the commitment duration are interpreted, and then the three typical negotiation protocols are formally defined and compared — nothing-guaranteed protocol, acceptance-guaranteed protocol, and finite-time guarantee protocol — which can be incorporated into TBNF. The TBNF should provide a background for efficient and effective electronic commerce negotiation while accommodating each agent’s adaptive negotiation strategy.

Key Word

Communication protocols; Multi-agent negotiation; Electronic commerce; Contract Net Protocol; Multi-agent coordination

Impacts and Limitations of Intelligent Agents to Internet Commerce

Jin, D. Lee, K, “Impacts and Limitations of Intelligent Agents to Internet Commerce,” Lecture Notes in Computer Science, vol. 2105, pp. 33-48, July, 2001.pdf


Agent-based economy or agent-based electronic commerce is the term for describing one of possible next steps of electronic commerce. The systematic understanding of the agent-based economy is important for researchers to develop practical intelligent agent systems, and for current electronic commerce industries to cope with the challenges of the intelligent agents. With these purposes, we conduct a comprehensive review of ongoing and future impacts of intelligent agents to electronic commerce from business model perspective. We classify intelligent agents by their functions and roles in electronic commerce and analyze the business model change by intelligent agents, based on Timmers’s definition of business model. Changes in architecture of flows, responses of players, influences to revenue model and participant’s benefits, and funding source are discussed with real world business examples and related researches. We also discuss the limitations of intelligent agents in electronic commerce.

A Peer-to-Peer CF-Recommendation for Ubiquitous Environment

Kim, H., Lee, K., Kim, J., A Peer-to-Peer CF-Recommendation for Ubiquitous Environment, Lecture Notes in Computer Science 4088: 678-683, 2006.pdf


In ubiquitous environment where all entities can freely connect and collaborate with each other from anywhere, the amount of accessible information is overwhelming and desired information often remains unfound. So there is a growing need to provide the personalized recommendation services for the customers in ubiquitous space. This paper suggests a UREC_P2P (U-Recommendation by peer-to-peer), a recommendation procedure in ubiquitous environment adopting P2P technologies combined with collaborative filtering algorithm. UREC_P2P is implemented and comparatively evaluated with a CFbased recommender system in client-server environment. The evaluation result shows that UREC_P2P has a good potential to be a preeminent and realistic solution to the recommendation problems encountered in ubiquitous environment.