Earticle

This research aims to investigate the flow analysis of LNG ship due to the different shapes of the ship front. Velocity and pressure distribution of fluid at the front portion of ship are numerically calculated for the optimum ship design of front with three different ship speeds for two different front shapes of ship. These numerical calculations are only applied for the immersed part of ship at the ocean. In addition, the coefficient of pressure drag and total drag are numerically obtained. Ultimately, the energy-efficient shape of LNG ship are determined through two different body shapes with three different ship speeds.

최근 기업의 생산성 향상을 위한 설계 및 생산 환경의 분산화에 따른 원격지 공동설계의 필요성이 증대되고 있다. 마찬가지로 선박설계 과정도 그 과정이 매우 복잡하고 많은 양의 데이터를 다루고 있는 작업으로서 그 환경이 분산화, 이질화됨에 따라 최근 들어 CSCW (Computer Supported Collaborative Work)의 요구가 증대되고 있다. 본 논문에서는 분산된 선박설계 환경에서의 원격지 공동설계를 지원하기 위한 에이전트기반 선박설계 시스템을 개발하였다. 특히 여기서는 에이전트간의 정보교환 및 지식공유 과정에서 발생하는 의사충돌 문제를 해결하기 위하여 사례기반 추론 기법을 이용하여 이의 해결을 시도하였다. 설계 에이전트, 이들을 중재하는 퍼실리테이터, 충돌 처리기, 그리고 사례기반 시스템의 유기적인 도움을 받아 설계자는 설계과정에서 발생하는 설계 시스템간의 의사충돌 문제에 대한 의사결정을 과거의 유사한 문제해결 사례로부터 효과적으로 처리할 수 있다.

Under the concept of global economy, the enterprises are assigning design and production environments around the world in different areas. A serious problem of information exchange emerges as companies use traditional hardware and very distinct softwares appropriate to their field of expertise. To overcome the decreased productivity due to the interruption of information, the concept of simultaneous engineering and concurrent design becomes very significant. In this article, an agent-based ship design system is developed in order to support a cooperation in distributed ship design environments. Above all, the conflicts that occur in the middle of knowledge sharing in the system must be resolved. An approach to do this is the case-based conflict resolution strategy formulated to resolve current conflict on the basis of previous resolved similar cases in agent-based collaborative design system environments. To do this conflict cases that occur in initial ship design stage are extracted. On the basis of the extracted cases, case-base is constructed. In addition conflict resolution handler located in the facilitator is developed to treat conflict problems effectively by reasoning of the case-base and thus presenting an appropriate solution. The validation of developed case-based conflict resolution strategy is evaluated by applying to collaborative design process in initial ship design stage, especially the machinery outfitting design, the preliminary design, the hullform design, and the structural design. Through the help of the cooperation of the design agents, the facilitator, the conflict resolution handler, and the case-based system, a designer can be supported effectively in his/her decision-making based on the previous cases resolved similarly.

This paper presents a conceptual design approach of air-cored synchronous machine with high temperature superconductor (HTS) field winding. With a given configuration of a target machine, boundary conditions are set in the cylindrical coordinate system and analytic field calculation is performed by solving a governing equation. To set proper boundary conditions, current distributions of the field winding and the armature winding are expressed by the Fourier expansion. Based on analytic magnetic field calculation results, key machine parameters are calculated: 1) inductance, 2) critical current of field winding, 3) weight, 4) HTS conductor consumption, and 5) efficiency. To investigate all potential design options, 6 sweeping parameters are determined to characterize the geometry of the machine and the parameter calculation process is performed for each design options. Among design options satisfying constraints including >80 % critical current margin and >95 % efficiency, in this paper, a first-cut design was selected in terms of overall machine weight and HTS conductor consumption to obtain a lightweight and economical design. The goal is to design a 5-MW machine by referring to the same capacity machine that was previously constructed by another group. Our design output is compared with finite element method (FEM) simulation to validate our design approach.

심해저광물자원인 망간단괴개발과정에서 효율적인 공정운영과 해양오염방지를 위한 PPLT(pre-pilot lifting test)급 선상선별처리장치가 고안되었다. 심해저로부터 양광되는 슬러리의 토출압력, 넓은 입도범위 및 염분을 함유한 해상 운전조건과 한정된 공간과 에너지를 고려하여 설계되었다. 선상선별농축장치는 진동스크린으로 구성된 1차 분리장치, 15인치 습식사이클론으로 구성된 2차 분리장치, 2인치 이하의 습식사이클론으로 구성된 정밀분리장치로 구성되었으며 1차 처리장치는 6.25 mm 입자의 분리, 2차 처리장치는 75 ㎛의 cut size를 나타내며, 정밀분리장치의 cut size 범위는 2-10 ㎛ 범위를 나타낸다.

This paper describes a preliminary ship design optimal design method in the process of hull form design. In the deterministic approach, an interdisciplinary ship design method integrates principal dimension decisions and hull form variations in the preliminary ship design stage. Integrated ship design, as presented in this paper, has the distinctive feature that these parameters are evaluated simultaneously. Conversely, in sequential design, which is based on the traditional preliminary ship design process, hull form designs and principal dimension decisions are determined separately and sequentially. The current study adopts the first method to enhance the design quality in the early design stage.

Most real world design evaluation and risk-based decision support combine quantitative and qualitative (linguistic) variables. Decision making based on conventional mathematics that combines qualitative and quantitative concepts always exhibit difficulty in modelling actual problems. The successful selection process for choosing a design/procurement proposal is based on a high degree of technical integrity, safety levels and low costs in construction, corrective measures, maintenance, operation, inspection and preventive measures. In this paper, a design decision support framework using a composite structure methodology grounded in approximate reasoning approach and evidential reasoning method is suggested for design evaluation of machinery space of a ship engine room at the initial stages. An illustrative example is used to demonstrate the application of the proposed framework.

The purpose of this study is to investigate the interrelationship of how the ship's wave resistance performance changes with the change of the longitudinal position of the section line in the ship's lines, and to find a way to use it in the hull-form design. To this end, we developed a hull-form automatic change algorithm that can maintain the proper hull-form while moving the section lines in the longitudinal direction, and the computer program for a numerical analysis was developed to apply the developed algorithm. By applying the developed hull-form automatic change algorithm and the wave resistance performance prediction program, the numerical analysis package was constructed. The numerical analysis was carried out for the passenger ship. Numerical analyzes were carried out by moving the section lines of the passenger ship in the longitudinal direction, and the results were compared with each other. Based on the numerical results, we attempted to investigate the correlation between the section line movement and the wave resistance performance.

In order support the design support system of small and medium-sized shipbuilding companies that carry out designs using 2D CAD, this study developed a system that automatically calculates the cable length by extracting the Y-axis value expressed as text data in 2D CAD. By setting the equipment where the cable starts and ends, the essential route and the installation rate were checked so that the optimal route of the cable could be calculated. As a result, the value calculated based on the optimal route and length of the cable by extracting the data of 2D CAD through this study was the same as the value previously calculated by the actual user, and the installation rate was less than 130% so there was no problem with the on-site installation. In addition, it was confirmed that the cable length calculated through this was reduced by about 7% compared to the existing work.

한국의 조선 산업은 수주량과 기술력을 바탕으로 세계 조선산업에서 1위의 자리를 지켜 왔다. 그리고 외화획득과 고용창출 등에 있어서 한국의 대표적인 효자산업이다. 2008년 한국의 조선 수출액은 431억달러로 자동차, 반도체를 제치고 처음으로 수출 1위를 차지했다. 그러나 모든 지표에서 세계선두이며 세계10대 조선소 중 7개가 한국의 조선소일 만큼 조선 강국이지만 한국 조선산업은 타 산업 분야에 비하여 디자인 기여도가 현저히 낮은 실정이다. 특히 선박 개발을 위한 디자인기술은 전무하다고 볼 수 있다. 유럽 선진국의 경우 일반 상선에서 고부가가치 선박으로의 전환을 성공하였고, 크루즈선 분야와 해양레저선박 분야에서 디자인 참여분야가 매우 크다. 디자인산업은 기술개발에 비해 적은 투자비용으로 단기간에 차별화, 고급화, 고부가가치화를 달성하여 상품의 경쟁력을 강화할 수 있는 수단이라는 것은 주지의 사실이다. 따라서 우리나라 조선산업의 경쟁력 강화와 부가가치 창출을 위해서는 디자인 산업과의 협력이 분명히 이루어져야 한다고 본다. 그러기 위해서는 디자인분야에서 많은 연구가 이루어져야 한다. 본 연구는 소형 선박의 외관에 한정하여 선박 설계의 특성을 감안한 선형 설계 디자인프로세스에 관한 것이다. 디자인분야에서 문제를 해결해가는 프로세스 구조에 견주어서 조선 설계 분야에서 다루어지는 선형설계 흐름도를 분석하여, 소형 선박 선형 디자인을 위한 프로세스를 제안하였다.

The Korea's shipbuilding industry has been ranked the world best based on the amount of orders and technology. And it is the representative industry in our country in part of the earning foreign exchange and the employment. In 2008, the total export amount of it($431hundred million ) took the first place for the first time, in advance of automobile, semiconductor. The Korea's shipbuilding industry is the first place according to all parts of the industrial indicators. Moreover, Korea has the 7 shipyards of the world top 10s. In spite of those positions as a shipbuilding powerhouse, our design contribution to it is significantly small compared to that of other industries. Especially, the basic design technology for a ship development merely exists. In Europe, the shipbuilding industry already succeeded in transfer from the commercial vessels to the high-valued marine ships. Also the participation of design is magnificent in the part of cruise and ships for leisure. It is well-known that, compared to developing technology, design industry could reinforce competitive advantage of products in short period with less expense. Therefore I think there must be cooperation with design industry in shipbuilding industry for high-value-added. This research is limited to small ships' exterior and it is about the design process for dull form considering the characteristics of ship-forming. I analyzed the flow of dull forms in shipbuilding industry part comparing the process of problem-solution in design part. And then I suggested the design process for a dull form of small vessels.

Manufacturing of complex surface plates in stern and stem is a major factor in cost of a preliminary ship design by computing process. If these hull plate parts are effectively classified, it helps to compute the processing cost and find the way to cut-down the processing cost. This paper presents a new method to classify surface plates effectively in the preliminary ship design using neural network. A neural-network-based ship hull plate classification program was developed and tested for the automatic classification of ship design. The input variables are regarded as Gaussian curvature distributions on the plate. Various applicable rules of network topology are applied in the ship design. In automation of hull plate classification, two different numbers of input variables are used. By observing the results of the proposed method, the effectiveness of the proposed method is discussed. As a result, high prediction rate was achieved in the ship design. Accordingly, to the initial design stage, the ship hull plate classification program can be used to predict the ship production cost. And the proposed method will contribute to reduce the production cost of ship.

Today's engineering design is carried out in a distributed fashion geographically or physically. This places new requirements on the computational environments such as efficient integration and collaboration. With the advances of the Internet and Network environment recently, many researches have been proposed and at the same time, Web-based distributed design gives to a new paradigm in design and manufacturing fields. That is, Web-based technologies lead to reduce the product development times and to ensure a competitive product in order to exchange and interact of real-time design information that integrates the distributed design environment between departments as well as companies via Internet and Web. So, an efficient data communication for design information sharing is the foundation for collaborative systems in the distributed environment. Design data communication techniques such as CORBA, DCOM and RMI have been considered in the existing research but they have some problems that are limitations of interoperability and firewall problems in the Web. Therefore, this paper presents a Web-based distributed design application where distributed design information resources are integrated and exchanged using Web Services for supporting XML and HTTP without the interoperability and firewall problems through the 330K VLCC case.

To decrease Europe's harmful emissions, the European Union aims to substantially increase its offshore wind energy capacity. To further develop offshore wind energy, investment in ever-larger construction vessels is necessary. However, this market is characterised by seemingly unpredictable growth of market demand, turbine capacity and distance from shore. Currently it is difficult to deal with such market uncertainty within the ship design process. This research aims to develop a method that is able to deal with market uncertainty in early ship design by increasing knowledge when design freedom is still high. The method uses uncertainty modelling prior to the requirement definition stage by performing global research into the market, and during the concept design stage by iteratively co-evolving the vessel design and business case in parallel. The method consists of three parts; simulating an expected market from data, modelling multiple vessel designs, and an uncertainty model that evaluates the performance of the vessels in the market. The case study into offshore wind foundation installation vessels showed that the method can provide valuable insight into the effect of ship parameters like main dimensions, crane size and ship speed on the performance in an uncertain market. These results were used to create a value robust design, which is capable of handling uncertainty without changes to the vessel. The developed method thus provides a way to deal with market uncertainty in the early ship design process.

The issues associated with the application of CFD for ship design are addressed. Doubtlessly at the moment, CFD tools are very useful in evaluating hull forms prior to traditional towing tank tests. However, time-consuming pre-processing is an obstacle in the daily application of CFD tools to improve hull forms. The accuracy of computational modeling without sacrificing the usability of CFD system is also to be assessed. The wave generation is still predicted by using potential panel methods, while velocity profiles entering into propeller plane is solved using turbulent flow solvers. The choice of turbulence model is a key to predict nominal wake distribution within acceptable accuracy. The experimental data for CFD validation are invaluable to improve physical and numerical modeling. Other applications of CFD for ship design than hull form improvement are also given. It is certain that CFD can be a cost-effective tool for the design of new and better ships.

The purpose of this paper is to develop a neurofuzzy modeling & inference system which can determine principle dimensions and hull factors in an initial ship design. Neurofuzzy modeling & inference for a hull form design (NeFHull) applies the given input-output data to the fuzzy theory. NeFHull also deals the fuzzificated values with neural networks. NeFHull redefines normalized input-output data as membership functions and executes the fuzzficated information with backporpagation-neural -networks. A hybrid learning algorithms utilized in the training of neural networks and examining the usefulness of suggested method through mathematical and mechanical examples.

Seakeeping analysis has progressed from the linear frequency-domain 2D strip method to the nonlinear timedomain 3D panel method. Nevertheless, the violent free surface flows such as slamming and green water on deck are beyond the scope of traditional panel methods based on potential theory. Recently, Computational Fluid Dynamics (CFD) has become an attractive numerical tool that can effectively deal with the violent free surface flows. ABS, as a classification society, is putting forth a significant amount of effort to implement the CFD technology to the advanced strength assessment of modern commercial ships and high-speed naval craft. The main objective of this study is to validate the CFD technology as a seakeeping tool for ship design considering fully nonlinear three-dimensional slamming and green water on deck. The structural loads on a large container carrier were successfully calculated from the CFD analysis and validated with segmented model test measurements.

Recently the importance of the utilization of engineering data is gradually increasing. Engineering data contains the experiences and know-how of experts. Data mining technique is useful to extract knowledge or information from the accumulated existing data. This paper deals with generating optimal polynomials using genetic programming (GP) as the module of Data Mining system. Low order Taylor series are used to approximate the polynomial easily as a nonlinear function to fit the accumulated data. The overfitting problem is unavoidable because in real applications, the size of learning samples is minimal. This problem can be handled with the extended data set and function node stabilization method. The Data Mining system for the ship design based on polynomial genetic programming is presented.

This paper introduces the use of network theory to model and analyze disparate ship design information. This work will focus on a ship's distributed systems and their intra- and intersystem structures and interactions. The three system to be analyzed are: a passageway system, an electrical system, and a fire fighting system. These systems will be analyzed individually using common network metrics to glean information regarding their structures and attributes. The systems will also be subjected to community detection algorithms both separately and as a multiplex network to compare their similarities, differences, and interactions. Network theory will be shown to be useful in the early design stage due to its simplicity and ability to model any shipboard system.

With the increase of the importance of the safety and environmental protection at sea, safety is a core design factor of maritime systems. Safety is defined as a perceived quality that determines to what extent the management, engineering and operation of a system is free of danger to life, property and the environment (Kuo 1998). There are many possible ways of dealing with the safety of ships. The rule-based approach is most commonly used in ship design. However there are many drawbacks to assure the safety objectives for a new ship and marine systems. This paper aims to investigate a systematic and rational approach to achieve the safety objectives of new ship in design process. Risk-based methodologies including the FSA (Formal Safety Assessment) and their applications to maritime systems are reviewed. Based on the principles of systems engineering and risk assessment, a process of safety assessment in ship design is established and proposed.

Software written in academic environments is rarely integrated and/or reused. Moreover, typical academic software products do not communicate with commercial CAD packages, consequently functionality that is readily available to industry is not available do academic researchers. The Surface Design Library (SDL) is a library serving as a framework under which, CAGD software, intended for research or educational use, can be written in such a manner that it becomes a reusable part of a useful CAGD system. Moreover SDL is equipped with an IGES translator so that it communicates with commercial CAD packages, This paper gives a brief overview to SDL and presents examples of using it for high quality fairing performed on a naval ship hull, before employing commercial CAD packages for further design and analysis.