Dongkon Lee

An approach to case-based system for conceptual ship design assistant

Abstract Designers heavily depend on their experience and existing ship data, when designing a ship. In preliminary design stage especially, decision making based on the designer’s expertise and heuristic knowledge are very important factors to design process because available information is limited, and cannot be fully supported by formal design procedure and design sheet. To support these conceptual design environment, the designer’s experience and heuristic knowledge are transformed into readable formats which can be operated on computer systems. The existing ship data are very useful and important in conceptual design. To use this data efficiently, it requires basically database of the existing ships and make practical application of it. In this article, intelligent system that can be a support to the conceptual design stage based on knowledge engineering was developed. Major design factors and parameters of the existing ship data were stored case base as design cases and the case base was connected with database for information exchange among them [Brown, A., Watson, I., & Filer, N. (1995). Separating the cases from the data: towards more flexible case-based reasoning. Proc. of International Conference on Case-Based Reasoning 95 (ICCBR-95), Sesimbra in Portugal]. To extract a good and suitable design case for a new ship design from case base, learning algorithm was adapted. The obtained knowledge from designers was used to compensate for the differences between the design case and a new design. The developed interactive intelligent conceptual design system (BASCON-IV) can be applied to commercial ships and bulk carriers.

Object-oriented approach to a knowledge-based structural design system

Abstract In this article, an Expert System for MIDship section design (ESMID) is developed based on a general-purpose expert system shell. The system focuses on the integration of knowledge-based system and design resources such as an engineering database, graphical user interface, and engineering application programs for the calculation of section modulus and longitudinal strength of ship structure. The validation of the ESMID system was examined and verified by applying the system to the 64K bulk carrier ship. The developed expert system can help a novice engineer in designing the midship section of ship.

A knowledge-based expert system as a pre-post processor in engineering optimization

Abstract Although conventional computer programs use efficient and precise optimization algorithms, they cannot emulate the problem-solving capabilities of human experts. A design optimization process involves a number of tasks which require human expertise and experience. Traditional optimization systems have concentrated on numerical aspects of a design process and have not been successful in integrating the numerical parts with human expertise. Numerical processes such as analysis, simulation and optimization are frequently used in design. In this paper, a design system which has the capabilities of knowledge processing and numerical computation by integrating the multiobjective optimization method and the knowledge-based system was developed. To generate the Pareto optimal set efficiently based on the constraint method, a hybrid optimization method is developed by coupling the genetic algorithm and the direct search method The knowledge-based system for symbolic processing is also developed. Rules for knowledge representation and the inference mechanism of the system are written in LISP. There are 147 rules altogether in the rule base. The knowledge-based multiobjective optimum design system is finally developed by integrating the multiobjective optimization method and the knowledge-based system. The system is applied to an optimum design of a ship in the preliminary design stage. It is found that the system well simulates design variables and objective functions of the design model. Copyright 1996 Elsevier Science Ltd

Development of the Motion Monitoring System of a Ship

A ship in a sea cruises with rolling, pitching, heaving etc because of environmental causes such as wind and wave. Those motions make crews or passengers feel inconvenience and they feel acceleration changes. Therefore, if lateral and vertical accelerations can be measured at a specific position in a ship, it can be known how discomfortable crews or passengers are. The motion monitoring system developed in this paper consists of measuring and communicating part including five accelerometers and gyro and a main computer which acquires measuring data and calculates motion indices. MSI(Motion Sickness Incidence) and MII(Motion Induced Interrupt) are calculated in real time using measured acceleration and angular rate. The validity of the developed system was confirmed through the real ship test of Hannara which is the school ship of Korea Maritime University.

Employment of wireless sensor networks for full-scale ship application

In this study, basic experiments regarding the wireless sensor network were conducted on a 3,000-ton-class training ship as the first step in applying the ubiquitous technology to a real ship. Various application fields of the technology in terms of the provision of safety and convenience on a ship would be extracted through these experiments. To efficiently adopt the ubiquitous technology for ship application, it is necessary to identify the state-of-the-art ubiquitous technology and to prepare countermeasures against the harsh environment of a ship. Especially, the characteristics of the wireless sensor network were investigated at the test bed ashore as well as on a real ship to figure out the complementary items before full-scale ship application.

Applying Memory-Based Learning to Indexing of Reference Ships for Case-Based Conceptual Ship Design

This paper presents a method of applying a memory-based learning (MBL) technique to automatic building of an indexing scheme for accessing reference cases during the conceptual design phase of a new ship. The conceptual ship design process begins with selecting previously designed reference ships of the same type with similar sizes and speeds. These reference ships are used for deriving an initial design of a new ship, and then the initial design is kept modified and repaired until the design reaches a level of satisfactory quality. The selection of good reference ships is essential for deriving a good initial design, and the quality of the initial design affects the efficiency and quality of the whole conceptual design process. The selection of reference ships has so far been done by design experts relying on their experience and engineering knowledge of ship design and structural mechanics. We developed an MBL method that can build an effective indexing scheme for retrieving good reference cases from a case base of previous ship designs. Empirical results show that the indexing scheme generated by MBL outperforms those by other learning methods such as the decision tree learning.

Experimental Tests on the Wireless Sensor Network and the Power-line Communication in a Real Ship and Laboratory

Abstract Basic performances of wireless sensor network (WSN) and power line communication (PLC) confirmed in the test bed ashore are investigated in the 3000-ton class training ship of Korea Maritime University. The ubiquitous technologies can be considered for the provision of safety and convenience in a ship. We employed WSN and PLC, as the ubiquitous technologies, at the two areas within the training s hip to estimate the realization of the ubiquitous environments in a ship. The experiments show rather good results in terms of data transfer rate. However, more detailed studies concerning the connection between WSN and PLC, noises induced to power line and fading ef fects are required to improve the quality and the stability of the communication for the ubiquitous environments. ※Keywords: Ship(선박), Wireless senor network(무선센서통신망), Zigbee(지그비), Power line communication(전력선 통신), Ubiquitous(유비쿼터스) 1. 서 론 언제 어디서나 필요한 정보를 얻어 필요한 서비 접수일: 2007년 12월 3일, 승인일: 2008년 5월 6일 †교신저자: ppaik@moeri.re.kr, 019-358-0255

A Study on USN Technologies for Ships

This paper describes the ubiquitous computing technologies for ship, which is produced and assembled by many steel blocks. It particularly describes the testing of a 2.4 GHz wireless communications platform, especially zigbee, on a number of intelligent devices, with the blocks disturbing the wireless communication. The power line communication that is established in a ship already is also experimented for some data transfer. At last, the RFID technology is applied at the test bed that is composed of three steel containers. In this paper, we implemented some USN technologies in the test bed simulating a ship environment and investigated the basic characteristics of ubiquitous computing technologies. Possible applications of such ubiquitous computing technologies to ships are also introduced here in.

A Study on the Survivability Assessment System of Damaged Ships

Ship damage due to maritime casualties lead to marine pollution, loss of life and properties. The maritime casualties come from the rough sea and bad weather condition generally. Therefore the large-scaled casualties will be derived from loss of structural strength and stability due to the progressive flooding and enlargement of damage by the effect of wave and wind. The improvement of damage survivability is very important in maritime safety This paper described the damage survivability assessment system which can be evaluate and improve the ship safety in consideration of loading, sea and damage condition. The components of the system and decision criteria for damage stability and structural safety is established. The ship modeler and behavior analysis program in wave is developed. Finally further research work is also discussed.

Development of Design Technology for Safety Enhancement of Damaged Ship

AbstractLoss of human lives and properties including environmental dama ge due to large scale accidents requires change of our perception to marine saf ety. IMO is trying to re-establish overall marine safety system through long term plan such as GBS. Along this line, current regulation based safety evaluation is in pro cess of changing into performance based methods, and for this transition, simulation based safety evaluation during design stage considering damage is highly necessary. In this paper, first, damage scenario is developed from IMO regulations and accident case studies. Then an integrated and simulation based safety evaluation prototype system considering both damage stability and structural safety is developed for the use during ship design process. ※Keywords: Marine accident(해양사고), Damaged ship(손상선박), Safety as sessment(안전성평가), Design technology(설계기술), Compartment modification(구획변경) 1. 서론 해양사고를 방지하고 해양사고로부터 인명과 재산 및 환경보호를 위한 각종 노력이 국제해사기구 접수일: 2008년 2월 25일, 승인일: 2009년 1월 13일✝교신저자: dklee@moeri.re.kr, 042-868-7222