• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.450-455
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• 1995

A three-dimensional numerical tool is developed to calculate the potential distribution, electric field, and conductance for any types of conductance probes immersed in the wavy liquid film with various shapes of its free surface. The tool is validated against various analytical solutions. It is applied to find out the characteristics of the wire-wire probe, the flush-wire probe and the flush-flush probe in terms of resolution, linearity, and sensitivity. The wire-wire probe shows high resolution and excellent linearity for various film thickness, but comparably low sensitivity for low film thickness fixed. The flush-wire probe shows good linearity and high sensitivity for varying film thickness, but resolution degrading with an increase in film thickness. In order to check the applicability of the three types of probes in the real situation, the Korteweg-de Vries(KdV) two-dimensional solitary wave is simulated. The wire-wire probe is strongly affected by the installation direction of the two wires; when the wires are installed perpendicularly to the flow direction, the wire-wire probe shows large distortion of the solitary wave. In order to measure the transverse profile of waves, the wire-wire probes and the flush-wire probes are required to be separately installed 2mm and 2mm, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.4
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• pp.134-140
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• 2009

The feasibility of electrochemical drilling and milling on stainless steel are investigated using tungsten microelectrode with $10{\mu}m$ in diameter. For the development of environmentally friendly and safe electrochemical process, citric acid solution is used as electrolyte. A few hundred nanoseconds duration pulses are applied between the microelectrode and work material for dissolution localization. Tool fracture by Joule heating, micro welding, capillary phenomenon, tool wandering by the generated bubbles are observed and their effects on micro ECM are discussed. Occasionally, complex textures including micro pitting corrosion marks appeared on the hole inner surface. Metal growth is also observed under the weak electric conditions and it hinders further dissolutions for workpiece penetration. By adjusting appropriate pulse and chemical conditions, micro holes of $37{\mu}m$ in diameter with $100{\mu}m$ in depth and 26Jim in diameter with $50{\mu}m$ in depth are drilled on stainless steel 304. Also, micro grooves with $18{\mu}m$ width and complex micro hand pattern are machined by electrochemical milling.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.2
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• pp.149-157
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• 2015

Ball and roller bearings are commonly used machine elements for supporting rotating motion about shafts in simple devices including bicycles, in-line skates, and electric motors, as well as in complex machines. Heat is generated by the friction in the bearings, which causes the temperature inside the bearing to increase. If the heat is not appropriately removed from the bearing, elevated temperatures may give rise to premature failure. It is, therefore, important to be able to calculate the temperature in the bearings due to friction.Here, we describe a method to estimate the frictional torque in bearings using an empirical formula developed using a method based on bearing analysis tool and the measured frictional torque in a spindle system. Thermal analysis of the spindle system including the bearings was achieved using the finite element method (FEM), and the bearing temperature was compared with measured data to verify the empirical formula.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1093-1094
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• 2006

City Train Technology that is large and complex system and consists of mechanical, electronic, electric, materials, computer, communication, civil/track etc. is very important area of railway industry, national fundamental industry. The standardization of city train system as a public transportation method and foundation of national economy is very important in order to do effective operation and to get fundamental technology, and the information system of the standards is required to operate the city train system effectively. By building data base of city train system design knowledge using computer-aided system engineering tool-Cradle, the system development issues and the design solutions are used by all engaged persons, and are managed by modeling and documentation. And this system will support architecture design consistently and effectively by applying this system to formalize early development process, to system requirements and configuration management, to system interface analysis and management and to system behavior analysis etc.. This study is for construction of data base of system design knowledge through making data base of many kinds of standards using CASE tool based on System Engineering Process, and introduces a model to support concurrent engineering for all engineers involved in system development allowing access to standard DB through Web from anywhere and at anytime.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.24-31
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• 2013

More than 23% of total nation's energy is consumed by residential building and 57.2% of Korean people are living in apartment. This study was carried out to two kind of process. First, after selecting one standard apartment, our research team investigate realistic energy consumption. Second, using 3-dimension heat transfer tool(TRISCO RADICON) and building energy simulation tool(Visual DOE) As a result, amount of heating and hot-water energy is composed of above 80 percent in standard apartment. And, after applying high performance technologies to standard apartment, namely, after being green home apartment, total energy consumption is reduced by54.6 percent. Also, because of energy consumption characteristics of green home apartment, for making more high performance green home apartment, especially, we have to figure out effective method to reduce electric and hot water energy.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.17 no.2
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• pp.177-186
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• 2010

Purpose: The purpose of this descriptive study was to investigate the application of physical restraints in ICUs of a university hospital. Method: Data were collected from August 1 to October 1 2009, using a recording tool from Electric Nursing Records and an observation tool for physical restraints and related factors. Frequency, percentage, and paired t-test with the SPSS/WIN 16.0 program were used to analyze the data. Results: The application rate for physical restraints in 5 ICUs was 34.3%, the highest application rate was 48.4% in the neurosurgical ICU. The mean frequency for physical restraint application per patient was 1.14, and the mean hours of restraint application per incident was 113.01 hours. The most common complications of physical restraints were bruising and edema. Conclusion: Many ICU nurses use physical restraints when caring for patients who are at high risk for falls, including patients have high levels of acuity, decreased level of consciousness or increased irritability. When physical restraints are applied, patients show resistance against the use resulting in side effects of bruising and edema. Therefore, nurses should observe changes in restrain sites, perform nursing interventions to prevent complications, and minimize the use of physical restraints.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1253-1258
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• 2006

As a global effort to conservate the environment, life cycle assessment(LCA) which considers the environmental impact through the life cycle of a product, from acquiring of resources to scrapping, has been actively applied. The LCA is a tool to calculate quantitatively the environmental impacts caused by products or services through their life cycles. Eco-efficiency need that express value of environmental impact provision EMU and develops in two forms according to use target of Eco-efficiency as a tool that environmental impact of EMU. It is a strategic instrument which assists stakeholders to understand which products, processes or services to target with future investments and which are not by comparing economic and ecological values. The results stand for aggregated information on economical value and environmental impact. Also, In this method, it is important to derive EPI(Environmental Performance Index) and SPI(Service Performance Index) from the sources available. The following is used as one of Eco-efficiency tools to achieve the target performance of processes, products and services for designer or projector. According to the eco-efficiency methodology for EMU developed in this study, the user definition and the DB design were carried out as a basic design of eco-efficiency S/W.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.1
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• pp.63-68
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• 2002

In this paper harmonic diagnose tool is described for electric evaluate the power quality at industrial power systems is described both simulation and experimental testing during various operation conditions. PTW (Power Tools for Windows) and harmonic measuring instrument are organized around personal computer and/or instrumentation study environments interconnected via RS-232. Unknown zero sequence impedance data of cable is calculated by the modified T&D and BICC method. IEEE standard is also used to estimate the transformer input data. the proposed system provides a flexible and effective environment to diagnose the power quality at industrial distribution systems by utilizing simulations and actual field data.

• KIEE International Transactions on Power Engineering
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• v.5A no.3
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• pp.244-251
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• 2005

Power transfer capability has been recently highlighted as a key issue in many utilities. It is determined by the thermal stability, dynamic stability and voltage stability limits of generation and transmission systems. In particular, voltage stability affects power transfer capability to a great extent in many power systems. This paper presents a tool for determining total transfer capability from a static voltage stability viewpoint using IPLAN, which is a high level language used with the PSS/E program. The tool was developed so as to analyze static voltage stability and to determine the total transfer capability between different areas from a static voltage stability viewpoint by tracing stationary behaviors of power systems. A unified power flow controller (UPFC) is applied for enhancing total transfer capability between different areas from the viewpoint of static voltage stability. Evaluation of the total transfer capability of a practical KEPCO power system is performed from the point of view of static voltage stability, and the effect of enhancing the total transfer capability by UPFC is analyzed.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.2
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• pp.1-10
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• 2022

In general, similar or previous projects are mainly referred to in order to derive operational test and evaluation(OT&E) items after acquiring weapon system. The idea that a more systematic method is needed is spreading because some of OT&E items derived in this process are redundant or unnecessary. Therefore, in this topic, we plan to use WBS, a tool that classifies components into a hierarchical structure and manages development easily to achieve the weapon system development goal. In addition, the WBS tool is applied to the medium-sized standard vehicle project, which is currently being research and developed, to effectively derive OT&E items. As a result of deriving OT&E items by applying WBS to the vehicle development field and electric devices of the medium-sized standard vehicle project, the operability and relationship were judged early, and then contents of the evaluation items could be written substantially while working on environmental adaptability. In the future, it is judged that the efficiency will be increased if the method discussed in this paper is applied when deriving the OT&E items from the R&D development project.