• Proceedings of the Membrane Society of Korea Conference
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• 2004.07a
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• pp.57-68
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• 2004

A demonstrative operation of a membrane system with its caparity of 3,600m$^3$/d was carried out using reservoir water as raw water for the application of membrane filtration system to drinking water treatment. The operation was undertaken at a constant flux of 0.9 m$^3$/m$^2$/d for three months. Backwashing with NaClO of 3 ppm was allowed for 30 seconds every 20 minutes of filtration. Physical cleaning was introduced after 69 times of filtration/backwashing cycle with air-scrubbing and backwashing for 1 minute, and flushing for 2 minutes. In this study, water treatment performance was investigated compared with the existing rapid sand filtration process. The membrane system was operated with no significant problems during the test period. Higher water quality was obtained in the membrane filtration than in the rapid sand filtration in terms of particulate matters such as turbidity and microbes. Although the finished water of the membrane filtration contained slightly higher concentration in dissolved matters than that of the conventional one, it met the drinking water standard. The demonstrative operation showed that membrane filtration has a reliability in drinking water treatment. Researches should be needed on cost analysis through long-term operation and optimization of operation condition for further application.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.15-20
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• 2018

This paper presents the method of ESS energy capacity calculation for stand-alone renewable energy generation system consisting of photovoltaic energy. There is almost no power from photovoltaic system during sunless days. So this source is very weak in terms of the power supply reliability. To improve problem of power supply, battery is mainly used Energy Storage System(ESS). The number of sunless days and Depth of Discharge(DOD) is important factor to determine energy capacity of battery. However, a many study for economical design is required due to the high cost of ESS. In this paper, we propose the new method of ESS energy capacity calculation by applying different DOD for operation with and without sun. We determine the Battery capacity using higher DOD of operation during sunless day than the DOD of the normal operation. And we carried out an economic analysis of the calculation results.

• Journal of Welding and Joining
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• v.29 no.4
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• pp.41-47
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• 2011

GMA welding process is a production process to improve productivity for the provision of higher welding quality of material. These includes numerous process variables that could affect welding quality, productivity and cost savings. Recently, the welding part of construction equipment had frequent failure of major components in the welding part of each subsidiary material due to shock which is very poor according to the welding part. Therefore, the implementation of sound welding procedure is the most decisive factor for the reliability of construction machinery. The data generated through experiments conducted in this study has validated its effectiveness for the optimization of bead geometry and process variables is presented. The criteria to control the process parameters, to achieve a good bead geometry. This study has developed mathematical models and algorithms to predict or control the bead geometry in GMA fillet welding process.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.102-105
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• 2000

Recently, applications of integrated large composite structures have been attempted to many structures of vehicles. To improve the cost performance and reliability of the integrated composite structures, it is necessary to judge structural integrity of the composite structures. For the judgement, we need fracture simulation techniques for composite structures. Many researches oil the fracture simulation method using FEM have been reported by now. Most of the researches carried out simulations considering only matrix cracking and fiber breaking as fracture modes, and did not consider delamination. Several papers have reported the delamination simulation, but all these reports require three-dimensional elements or quasi three- dimensional elements for FEM analysis. Among fracture mechanisms of composite laminates, delamination is the most important factor because it causes stiffness degradation in composite structures. It is known that onset and propagation of delamination are dominated by the strain energy release rate and interfacial moment. In this study, laminated composite has been described by using 3 dimensional finite elements. Then impact behavior of the laminated composite is simulated using FEM(ABAQUS/Explicit) with progressive failure mechanism. These results are compared with experimental results.

• ETRI Journal
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• v.33 no.6
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• pp.864-870
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• 2011

As an isotropic conductive adhesive, that is, a hybrid Cu paste composed of Cu powder, solder powder, and a fluxing resin system, has been quantitatively characterized. The mechanism of an electrical connection based on a novel concept of electrical conduction is experimentally characterized using an analysis of a differential scanning calorimeter and scanning electron microscope energy-dispersive X-ray spectroscopy. The oxide on the metal surface is sufficiently removed with an increase in temperature, and intermetallic compounds between the Cu and melted solder are simultaneously generated, leading to an electrical connection. The reliability of the hybrid Cu paste is experimentally identified and compared with existing Ag paste. As an example of a practical application, the hybrid Cu paste is used for LED packaging, and its electrical and thermal performances are compared with the commercialized Ag paste. In the present research, it is proved that, except the optical function, the electrical and thermal performances are similar to pre-existing Ag paste. The hybrid Cu paste could be used as an isotropic conductive adhesive due to its low production cost.

• The Journal of Information Systems
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• v.15 no.4
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• pp.247-268
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• 2006

We introduce about XBRL, eXtensible Business Reporting Language, which is widely accepted as the international standard language for business financial reporting. XBRL is a language for the electronic communication of business and financial data which is revolutionizing business reporting around the world. It provides major benefits in the preparation, analysis and communication of business information. It offers cost savings, greater efficiency and improved accuracy and reliability to all those involved in supplying or using financial data. XBRL is a kind of XML application based on the open Internet technologies. We propose a framework for enterprise information supply chain using XBRL Web services. A Web service is defined as a software system based on XML and designed to support interoperable machine-to-machine interaction over a network by the W3C. Web services are frequently just application programming interfaces (API) that can be accessed over a network, such as the internet and executed on a remote system hosting the requested services. An XBRL Web service-based enterprise information supply chain enables for companies to implement seamless information supply chains from businesses to financial institutions, to supervisory authorities, and to other stake holders for real time information access. And thereby it is expected to contribute to the increase in the value of companies due to the enhanced visibility and transparency of accounting and management.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.65-71
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• 2020

Worldwide plant market keeps maintaining steady growth rate and along with this trend, domestic plant market and its contractors also maintain such growing tendency. However, in spite of its external growth, win-win growth of domestic material industry that occupies the biggest share in plant industry cost portion is extremely marginal in reality. Domestic plant material suppliers are required to increase awareness of domestic material brand by securing quality and reliability of international standard through improvement of design quality superior to that of overseas material suppliers. Improvement of design quality of plant material becomes an essential element, not an option, for survival of domestic plant industry and its suppliers. Under this background, in this study, priority and importance by each evaluation index was analyzed by materializing plant design stage through survey of experts and defining evaluation index by each design stage and based on this analysis result, evaluation index of stage-gate based decision-making process that may improve design quality of plant material was suggested. It is considered that by utilizing evaluation index of stage-gate based decision-making process being suggested in this study, effective and efficient decision-making of project decision-makers would be enabled and it would be contributory to improve design quality of plant material.

• Journal of Korean Association for Spatial Structures
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• v.18 no.1
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• pp.67-75
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• 2018

Steel roof construction is on the most important and critical factors in the large spatial construction and necessary to be prepared under a radical planning. Therefore, the major management factors of steel roofing structure assembly must be critically reviewed during planning. Through the review process, it is necessary to reduce the construction cost, to prevent delays in the construction schedule, and to minimize construction errors. However, domestically due to the lack experience in large spatial constructions, a planning of roof construction is limited to have a radical planning. Especially due to unclear organization of the management factors in hierarchy, using them in reality for construction planning is difficult and reliability is low. Therefore, in this study, the goal is to conduct the major management factors in the large spatial construction. To achieve this, we have reviewed and analyzed the numbers of construction plans and construction reports and conducted a total 68 of the management factors. Based on the conducted factors, we have interviewed 16 experts with experience in large spatial construction. From the interview result, we have deduced the factors scored above 4.20 of 10 for critical factors. The results of this study will be used as a guidance for planning steel roofing structure assembly in large spatial construction. The critical factors will be provided to the site mangers for the quality management of large spatial constructions in practice.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.1
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• pp.102-108
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• 2000

The comparative evaluation/analysis of the initiation technologies currently being used, and the advanced initiation technologies currently being developed lot the aerospace and defense applications was performed. The evaluation criteria used were the compliance, performance, reliability, safety, and cost. The results clearly indicate that there is no one single initiation technology that will satisfy entire spectrum of initiation system requirements. Each initiation system architecture would require different initiation technologies that will satisfy the overall system performance requirements. However, laser initiation, particularly, the laser diode initiation has been getting more attention in recent years. The laser diode initiation, for most part, eliminates EMI and ESD concerns. In addition, laser diode initiation system can also be designed into relatively small packages, are optically connected systems by very light weight cables, are relatively easily designed to meet variety of initiation system requirements. Due to the these compelling factors, laser diode initiation has potential of becoming common initiation systems for many different aerospace and defense application.

• Smart Structures and Systems
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• v.12 no.2
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• pp.209-233
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• 2013

With an annual growth rate of about 30%, wind energy systems, such as wind turbines, represent one of the fastest growing renewable energy technologies. Continuous structural health monitoring of wind turbines can help improving structural reliability and facilitating optimal decisions with respect to maintenance and operation at minimum associated life-cycle costs. This paper presents an integrated monitoring system that is designed to support structural assessment and life-cycle management of wind turbines. The monitoring system systematically integrates a wide variety of hardware and software modules, including sensors and computer systems for automated data acquisition, data analysis and data archival, a multiagent-based system for self-diagnosis of sensor malfunctions, a model updating and damage detection framework for structural assessment, and a management module for monitoring the structural condition and the operational efficiency of the wind turbine. The monitoring system has been installed on a 500 kW wind turbine located in Germany. Since its initial deployment in 2009, the system automatically collects and processes structural, environmental, and operational wind turbine data. The results demonstrate the potential of the proposed approach not only to ensure continuous safety of the structures, but also to enable cost-efficient maintenance and operation of wind turbines.