• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.601-604
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• 1996

It is well known that steam generator water level control at low power operation has many difficulties in a PWR (pressurized water reactor) nuclear power plant. The reverse process responses known as shrink and swell effects make it difficult to control the steam generator water level at low power. A new automatic control logic to remove the reverse process responses is proposed in this paper. It is implemented in PLC (programmable logic controller) and evaluated by using test equipment in Korea Atomic Energy Research Institute. The simulation test shows that the performance requirements is met at low power (below 15%). The water level control by new control logic is stabilized within 1% fluctuation from setpoint, while the water level by YGN 3 and 4 control logic is unstable with the periodic fluctuation of 25% magnitude at 5% power.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.53-56
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• 2001

Reverse engineering has been widely used for the shape reconstruction of an object without CAD data and it includes some steps such as scanning of a clay or wood model, and generating some manufacturing data in an STL file. A new approach to remove point data with Delaunay triangulation is introduced to deal with the size problems of STL file and the difficulties in the operation of RP process. This approach can be used to reduce a number of measuring data from laser scanner within a specified tolerance, thus it can avoid the time for handing point data during modeling process and the time for verifying and slicing STL model during RP process. Developed software enables the user to specify the criteria for the selection of group of triangles either by the angle between triangles or the percentage of triangles reduced, and thus RP models with accuracy will be helpful to automated process.

• Textile Coloration and Finishing
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• v.10 no.4
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• pp.45-52
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• 1998

Reuse of wastewater become an important consideration to solve the environmental pollution problems in recent industriallzation and urbanization. Especially, he characteristic of dyeing process is subject to use much water and thus has serious problems for removal of color and organic pollutants in their wastewater. This report is divided into two main parts ： The purpose of the first part was to determine if alkaline wastewater discharged from textile dyeing operation factory could be flocculated directly by Fenton oxidation method. This study was conducted to investigate Fenton reagent dose and reaction condition of Fenton method as pretreatment for dyeing wastewater in K dyeing industry were investigated. In the second part of this research, to treat dyeing wastewater it was found that the most effective way is to use ultrafiltation and reverse osmosis at the conditions of the pH 7.0~8.0 and operating pressure of $2.5~35kg_f/cm^2$. This paper is mainly dealt with the application on reuse system of dyeing wastewater treatment using ultrafiltration and reverse osmosis membranes. The results showed that dyeing wastewater could be reused by chemical, filter and membrane sequential treatment process.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.1
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• pp.15-20
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• 2017

In order to advance and improve the performance of domestic aged power plants, IEDs have been developed for power generation systems. For smooth installation and operation of the protection relays, a detail settings study of IED is required. This paper deals with an analysis based on PSCAD and setting investigation of IED for loss of field, reverse power protection in Small Hydro Generation System.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.2
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• pp.201-210
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• 1999

Cyclones have been extensively used in the industry for removing fine particles from the gaseous streams, based on simplicity in design and construction in association with low cost and flexibility to operate in extreme and harsh environments. However, industrial cyclones are typically not very efficient for particles smaller than 10μm. In this work, in order to improve the separation efficiency of reverse flow cyclones, a simple device named Post Cyclone(Poc) in installed on the top of an existing cyclone. Thereby the residual swirl present at the outlet (vortex finder) of a conventional cyclone has been used to capture the escaped dust from the cyclone in the PoC. The performance of PoC was closely evaluated by changing configuration of the PoC and operation condition. In addition, the dust behaviour in th PoC was investigated based on the hypothesis of residual vortex.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.155-164
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• 2004

Many countries, including Korea, suffer from a shortage of freshwater. With increases in population and the quality of life, along with large-scale expansion in industrial and agricultural activities, more freshwater is needed. Available resources, Including ground water, are limited, and desalination presents the opportunity for a new unlimited source of freshwater from the sea. The objectives of this study were to test membrane performance in seawater desalination and to examine the quality of water produced. bath well and sea water were used as water sources. Typically used membrane for seawater desalination and high rejection seawater desalination membrane are maintained at almost same recovery rate and permeate flux, while the conductivity was lower in the operation of typically used seawater membrane. The treated water quality using two types of membranes is satisfied with the Korea drinking water quality standards.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.117-123
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• 2014

The fabrication and characterization of a Si/ZnO thin film heterojunction ultraviolet photodiode has been presented in this paper. ZnO thin film of ~100 nm thick was deposited on <100> Silicon (Si) wafer by atomic layer deposition (ALD) technique. The Photoluminescence spectroscopy confirms that as-deposited ZnO thin film has excellent visible-blind UV response with almost no defects in the visible region. The room temperature current-voltage characteristics of the n-ZnO thin film/p-Si photodiodes are measured under an UV illumination of $650{\mu}W$ at 365 nm in the applied voltage range of ${\pm}2V$. The current-voltage characteristics demonstrate an excellent UV photoresponse of the device in its reverse bias operation with a contrast ratio of ~ 1115 and responsivity of ~0.075 A/W at 2 V reverse bias voltage.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.746-748
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• 1993

To overcome the problem of the diode reverse recovery in high switching frequency inverter, a new gate drive scheme is proposed for IGBT in this paper. Using this circuit, the reverse recovery current can be controlled and faster switching time can be achieved for hard switching inverter. The over-current protection method, which is suitable for the proposed gate driver, is also presented. The operation of the proposed circuit is investigated and its usefulness is verified through the experimental results.

• Archives of Craniofacial Surgery
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• v.23 no.3
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• pp.134-138
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• 2022

The scalp is the thickest skin in the body and protects the intracranial structures. The coverage of a large scalp defect is a difficult surgical procedure, the full details of which must be considered prior to the procedure, such as defect size and depth, and various factors related to the patient's general condition. Although a free flap is the recommended surgical procedure to cover large scalp defects, it is a high-risk operation that is not appropriate for all patients. As such, other surgical options must be explored. We present the case of a patient with an ulcer on the scalp after wide excision and split-thickness skin graft for squamous cell cancer. We successfully performed a reverse temporalis muscle flap for this patient.

• Journal of Information Processing Systems
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• v.19 no.5
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• pp.702-712
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• 2023

Load balancing plays a crucial role in ensuring the stable operation of information management systems during periods of high user access requests; therefore, load balancing approaches should be reasonably selected. Moreover, appropriate load balancing techniques could also result in an appropriate allocation of system resources, improved system service, and economic benefits. Nginx is one of the most widely used loadbalancing software packages, and its deployment is representative of load-balancing application research. This study introduces Nginx into an educational administration system, builds a server cluster, and compares and sets the optimal cluster working strategy based on the characteristics of the system, Furthermore, it increases the stability of the system when user access is highly concurrent and uses the Nginx reverse proxy service function to improve the cluster's ability to resist illegal attacks. Finally, through concurrent access verification, the system cluster construction becomes stable and reliable, which significantly improves the performance of the information system service. This research could inform the selection and application of load-balancing software in information system services.