• Journal of Ocean Engineering and Technology
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• v.35 no.3
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• pp.173-182
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• 2021

The maneuvering performance of a ship on the actual sea is very different from that in calm water due to wave-induced motion. Enhancement of a ship's maneuverability in waves at the design stage is an important way to ensure that the ship navigates safely. This paper focuses on the maneuvering prediction of a Russian trawler in wind and irregular waves. First, a unified seakeeping and maneuvering analysis of a Russian trawler is proposed. The hydrodynamic forces acting on the hull in calm water were estimated using empirical formulas based on a database containing information on several fishing vessels. A simulation of the standard maneuvering of the Russian trawler was conducted in calm water, which was checked using the International Maritime Organization (IMO) standards for ship maneuvering. Second, a unified model of seakeeping and maneuvering that considers the effect of wind and waves is proposed. The wave forces were estimated by a three-dimensional (3D) panel program (ANSYS-AQWA) and used as a database when simulating the ship maneuvering in wind and irregular waves. The wind forces and moments acting on the Russian trawler are estimated using empirical formulas based on a database of wind-tunnel test results. Third, standard maneuvering of a Russian trawler was conducted in various directions under wind and irregular wave conditions. Finally, the influence of wind and wave directions on the drifting distance and drifting angle of the ship as it turns in a circle was found. North wind has a dominant influence on the turning trajectory of the trawler.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.127-133
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• 2005

DSME has successfully developed the unified CAD system (DACOS) for the commercial ship based on its design know-how accumulated for several years. Currently, DSME is expanding the unified CAD system to plant and special ship design. In this paper, the development of pipe design, especially, isometric drawing and BOM(Bill of Material) generation will be introduced isometric drawing and BOM generation are major activities of pipe design in shipbuilding. The drawing is used for pipe construction and installation while the BOM is used for purchasing and manufacturing pipe line. These activities are time-consuming and tedious jobs done by designers because the drawing should be generated as a non-scaled symbolized drawing that can be easily understood and the BOM information should be extracted without mistake. Therefore, we implemented automatic isometric drawing and 80M generation system for pipe design. In this paper, the developed system and the used technology will as well be introduced and a design output in a plant project as an applied example will be illustrated.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.257-258
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• 2007

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.79-84
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• 1992

An integrated design system has as its aim the incoporation of all the design processes, such as, planning, preliminary design, analysis, detailed design (mamber design), evaluation, and drafting into an unified software system. Successful implementation such a system could lead to major improvements in efficiency by eliminating duplication of data and efforts. reducing errors, saving design time, providing management support, and so on. This study presents a methodology for an computer-integrated design system for building structures, synthesizing algorithmic procedures and knowledge based expert systems on the network database. Network database, which was designed to store all information systematically during the design processes, provides centeral communication area between algorithms and expert systems. The conventional procedural codes automate the routine design phases such as structural analysis, whereas knowledge-based expert systems support designer's decisions at the creative design phases such as preliminary design etc. The user interface with interactive and batch modes controls the design phases and manages design information and activates the algorithms and the expert systems. The concept presented in this paper will contribute to the formulation of automated design systems for building structures.

• Korean Journal of Computational Design and Engineering
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• v.5 no.4
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• pp.359-372
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• 2000

Current CAD systems are good enough to be used as a tool to manipulate three-dimensional shapes. This is a very important capability to be owned by a design tool because a major portion of designers'activities is spent on the shape manipulation in the design detailing process. However, the whole design process involves a lot more than the, shape manipulation. Currently, these remaining tasks, mostly logical reasoning process for the function realization together with structure decomposition in the top-down manner, are processed in the designer's brain. To support the top-down functional design process of a mechanical product, a system integrating the functional, structural and geometrical aspects of a product design in a unified environment is presented. Using this system, a designer can perform function decomposition, structure decomposition, and geometry detailing, and function verification activities in parallel and the whole design process it modeled resultantly. Once the whole design process is modeled, any redesign task can be automatically performed with the verification of the desired functions.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.241-243
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• 2006

This paper describes experimental analysis of UPQC, which is composed of cascaded H-bridges and single-phase multi-winding transformers. The operational characteristic was analyzed through experimental works with a scaled model, and simulations with PSCAD/EMTDC. The UPQC proposed in this paper can be directly connected to the distribution line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual UPQC system applicable for the actual distribution system.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.395-399
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• 2001

In this paper, various reduced parts converter topologies and control strategies for power factor correction and motor control are reviewed and systematic design methodology is developed. From this investigation, the converter topologies could be mainly categorized into cascade type and unified type. The detailed operational principles are examined and the performance comparison is derived to illustrate merits and limitations of the converters. Simulation results are provided to help the better understanding of the theoretical description and several experimental results are presented on prototype induction motor better brush less dc (BLDC) motor drives, along with cascade and unified type converters.

• Structural Engineering and Mechanics
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• v.2 no.1
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• pp.1-16
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• 1994

A unified theory has recently been developed for reinforced concrete structures (Hsu 1993), subjected to the four basic actions - bending, axial load, shear and torsion. The theory has five components, namely, the struts-and-ties model, the equilibrium (or plasticity) truss model, the Bernoulli compatibility truss model, the Mohr compatibility truss model and the softened truss model. Because the last three models can satisfy the stress equilibrium, the strain compatibility and the constitutive laws of materials, they can predict not only the strength, but also the load-deformation history of a member. In this paper the five models are summarized to illustrate their intrinsic consistency.

• ETRI Journal
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• v.29 no.6
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• pp.820-822
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• 2007

ARIA and the Advanced Encryption Standard (AES) are next generation standard block cipher algorithms of Korea and the US, respectively. This letter presents an area-efficient unified hardware architecture of ARIA and AES. Both algorithms have 128-bit substitution permutation network (SPN) structures, and their substitution and permutation layers could be efficiently merged. Therefore, we propose a 128-bit processor architecture with resource sharing, which is capable of processing ARIA and AES. This is the first architecture which supports both algorithms. Furthermore, it requires only 19,056 logic gates and encrypts data at 720 Mbps and 1,047 Mbps for ARIA and AES, respectively.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2475-2477
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• 1999

This paper describes a simulation model and scaled hardware model to analyze the dynamic performance of Unified Power Flow Controller, which adjust flexibly the active and reactive power flow through the ac transmission line. The design of control system was developed using vector control method. The results of simulation and scaled hardware test show that the developed control system works accurately. And both models are very effective to analyze the dynamic performance of the Unified Power Flow Controller.