• 플랜트 저널
• /
• 제5권2호
• /
• pp.62-67
• /
• 2009

The capability of design and engineering of global EPC companies has long been equalized through past similar construction experiences. Among various key factors in the success of EPC project, the capability of engineering is considered to be the most important factor since the engineering is preceding activities of EPC contract. The failure of engineering may adversely affect the subsequent procurement & construction activities and in turn may cause cost overrun or schedule delay. Therefore, an EPC company needs to continue to improve the engineering capabilities for the success of project. The engineering capabilities can be further improved if the EPC company should prevent recurrence of similar design faults that were previously committed. This study is intended to present how to make the most of the failure examples from previous projects towards a success of project. Failure is but a stepping stone to success. The EPC company can obtain useful lessons from the analysis of past failure examples.

• 한국정밀공학회지
• /
• 제30권8호
• /
• pp.831-838
• /
• 2013

This paper focused on the design of an efficient temperature controller for a plant with a wide range of operating temperatures. The greater the temperature difference a plant has, the larger the nonlinearity it is exposed to in terms of heat transfer. For this reason, we divided the temperature range into five sections, and each was modeled using ARMAX(auto regressive moving average exogenous). The movement of the dominant poles of the sliced system was analyzed and, based on the variation in the system parameters with temperature, optimal control parameters were obtained through simulation and experiments. From the configurations for each section of the temperature range, a temperature-based gain-scheduled controller (TBGSC) was designed for parameter variation of the plant. Experiments showed that the TBGSC resulted in improved performance compared with an existing proportional integral derivative (PID) controller.

• 상하수도학회지
• /
• 제14권1호
• /
• pp.45-53
• /
• 2000

The optimum operation of domestic wastewater treatment plant can give influence on operational cost and future expansion in Korea where has 93 operational domestic wastewater treatment plants. Also, the study on optimum operation can reduce operation cost and budget of municipalities whom have responsibility of wastewater treatment plant operation. In this study, 9 domestic wastewater treatment plants which can represent 93 plants in Korea have been selected and operational data are gathered. The collected data are inputted to computer simulator based on IAWQ's Activated Sludge Model No.1 and optimum operation methods are developed. Also, the electric power for aeration which has large portion of overall operation cost are calculated based on design and operation conditions and these are compared. In this study, it was found that design wastewater characteristics are 1.6 times higher than those of daily maximum except for E plant and that estimation methods for design wastewater characteristics have to be improved. Based on computer simulation, we found there is no need to operate all aeration tanks due to weak influent overall power for aeration can be reduced to about 43% of design one.

• 한국CDE학회논문집
• /
• 제19권3호
• /
• pp.203-213
• /
• 2014

The O&M (Operation and Maintenance) phase of offshore plants with a long life cycle requires heavy charges and more efforts than the construction phase, and the occurrence of an accident of an offshore plant causes catastrophic damage. So previous studies have focused on design for reliability, and recently many studies have dealt with a maintenance system to prevent unexpected failures. Nowadays due to the emerging ICTs (Information Communication Technologies) and sensor technologies, it is possible to send health monitoring information of important equipment to administrator of an offshore plant in real time, which leads to having much concern on condition based maintenance policy or predictive maintenance. In this study, we have reviewed previous studies associated with condition-based maintenance of offshore plants, and introduced the approaches predicting failures of the compressor which is one of essential mechanical devices in LNG FPSO.

• Nuclear Engineering and Technology
• /
• 제49권8호
• /
• pp.1727-1732
• /
• 2017

Pyroprocessing is an alternative method of reprocessing spent fuel, usually involving the dissolving spent fuel in a molten salt media. The National Nuclear Laboratory designed, built, and commissioned a molten salt dynamics rig to investigate the transfer characteristics of molten lithium chloride-potassium chloride eutectic salt. The efficacy and flow characteristics of a high-temperature centrifugal pump and argon gas lift were obtained for pumping the molten salt at temperatures up to $500^{\circ}C$. The rig design proved suitable on an industrial scale and transfer methods appropriate for use in future molten salt systems. Corrosion within the rig was managed, and melting techniques were optimized to reduce stresses on the rig. The results obtained improve the understanding of molten salt transport dynamics, materials, and engineering design issues and support the industrialization of molten salts pyroprocessing.

• 한국CDE학회논문집
• /
• 제18권3호
• /
• pp.167-176
• /
• 2013

It is necessary to construct equipment catalog in ship outfitting design and offshore plant design. The three-dimensional CAD data of equipment take on different level-of-detail depending on the purpose. Equipment suppliers provide CAD data with high complexity while ship designers need CAD data with low complexity. Therefore, it is necessary to simplify CAD data. However, it takes much time to simplify them manually. To resolve the issue, a system for automatically simplifying the 3D CAD data of equipment was developed. This paper presents the architecture of the system and the implementation details. In addition, experiment result using the prototype system is explained.

• 복식
• /
• 제63권3호
• /
• pp.33-45
• /
• 2013

This work developed the basic motive design utilizing the physical beauty of the traditional ornaments used uniquely by Korean females and suggested some textile designs and fashion cultural product designs. As a research method, computer design programs Adobe Illustrator CS3 and Adobe Photoshop CS3 were used as well as literature examination. The motive was mainly based on the dwiggoji and ddeoljam, which are female ornaments. The formative shape in woman ornaments was classified into four kinds: plant, animal, geometry, and hybrid. The hybrid type was divided further into such combinations as plant, animal, and geometry, which came up with 8 fundamental motives for design development in total. With regard to the basic motive design, the coordinated concept was adopted with a combination of traditional taste and contemporary taste in harmony for the expression of delicate image on the condition that the basic format in female ornament is maintained. Textile design was processed with symmetry, rotation, repeat, and overlap as fundamental motive. As to the design for fashion cultural products, design mapping was proposed for neckties, handbags, clutches, shirts, and one-pieces. Utility and beauty in the traditional ornaments unique to Korean women could be recognized once again through this work. This work also assured the possibility for the endless improvement as a design development motive with originality.

• Nuclear Engineering and Technology
• /
• 제48권4호
• /
• pp.1047-1057
• /
• 2016

Design engineering process for field programmable gate array (FPGA)-based reactor trip functions are developed in this work. The process discussed in this work is based on the systems engineering approach. The overall design process is effectively implemented by combining with design and implementation processes. It transforms its overall development process from traditional V-model to Y-model. This approach gives the benefit of concurrent engineering of design work with software implementation. As a result, it reduces development time and effort. The design engineering process consisted of five activities, which are performed and discussed: needs/systems analysis; requirement analysis; functional analysis; design synthesis; and design verification and validation. Those activities are used to develop FPGA-based reactor bistable trip functions that trigger reactor trip when the process input value exceeds the setpoint. To implement design synthesis effectively, a model-based design technique is implied. The finite-state machine with data path structural modeling technique together with very high speed integrated circuit hardware description language and the Aldec Active-HDL tool are used to design, model, and verify the reactor bistable trip functions for nuclear power plants.

• Nuclear Engineering and Technology
• /
• 제54권5호
• /
• pp.1712-1725
• /
• 2022

For improving the seismic performance of the nuclear power plant (NPP) piping system, attempts have been made to apply a dynamic absorber (DA). However, the current piping DA design method is limited because it cannot provide the globally optimum values for the target design seismic loading. Therefore, this study proposes a seismic time history analysis-based DA optimal design method for piping. To this end, the Kriging approach is introduced to reduce the numerical cost required for seismic time history analyses. The appropriate design of the experiment method is used to increase the efficiency in securing response data. A gradient-based method is used to efficiently deal with the multi-dimensional unconstrained optimization problem of the DA optimal design. As a result, the proposed method showed an excellent response reduction effect in several responses compared to other optimal design methods. The proposed method showed that the average response reduction rate was about 9% less at the maximum acceleration, about 5% less at the maximum value of the response spectrum, about 9% less at the maximum relative displacement, and about 4% less at the maximum combined stress compared to existing optimal design methods. Therefore, the proposed method enables an effective optimal DA design method for mitigating seismic response in NPP piping in the future.

• 한국CDE학회논문집
• /
• 제18권1호
• /
• pp.21-27
• /
• 2013

Presented in the paper is a log data based modeling method for effective construction of a virtual plant model which can be used for the virtual PLC (Programmable Logic Controller) simulation. For the PLC simulation, the corresponding virtual plant, consisting of virtual devices, is required to interact with the input and output symbols of a PLC. In other words, the behavior of a virtual device should be the same as that of the real device. Conventionally, the DEVS (Discrete Event Systems Specifications) formalism has been used to represent the behavior a virtual device. The modeling using DEVS formalism, however, requires in-depth knowledge in the simulation area, as well as the significant amount of time and efforts. One of the key ideas of the proposed method is to generate a plant model based on the log data obtained from the production system. The proposed method is very intuitive, and it can be used to generate the full behavior model of a virtual device. The proposed approach was applied to an AGV (Automated Guided Vehicle).