• Tribology and Lubricants
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• v.25 no.4
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• pp.236-242
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• 2009

Oil viscosity is one of the important parameters for machinery condition monitoring. Basically, it is expressed as kinematic viscosity measured by capillary flow and dynamic or absolute viscosity measured by rotary shear viscometry. Recently, acoustic wave techniques appear in the market, measuring viscosity as the product of dynamic viscosity and density. For Newtonian fluids, knowledge of density allows conversion from one viscosity parameter to the other at a specific shear rate and temperature. In this work, oil samples with different chain lengths of viscosity index (VI) improvers and concentrations were examined by different viscometric techniques. Results showed that acoustic viscosity measurements give misleading results for oil samples with high molecular weight VI improvers and at low temperatures ${\leq}40^{\circ}C$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.457-462
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• 1995

This paper describes diagnosis strategy of the Flexible Multiple Fault Diagnosis Module for forecasting faults in system and deciding current machine state form sensor information. Most studydeal with diagnosis control stategy about single fault in a system, this studies deal with multiple fault diagnosis. This strategy is consist of diagnosis control module such as backward tracking expert system shell, various neural network, numerical model to predict machine state and communication module for information exchange and cooperate between each model. This models are used to describe structure, function and behavior of subsystem, complex component and total system. Hierarchical structure is very efficient to represent structural, functional and behavioral knowledge. FT(Fault Tree). ST(Symptom Tree), FCD(Fault Consequence Diagrapy), SGM(State Graph Model) and FFM(Functional Flow Model) are used to represent hierachical structure. In this study, IA(Intelligent Agent) concept is introduced to match FT component and event symbol in diagnosed system and to transfer message between each event process. Proposed diagnosis control module is made of IPC(Inter Process Communication) method under UNIX operating system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.778-784
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• 2002

FFU are used increasingly by the microeleceronics industry to provide clean recirculating air for the fabrication of integrated circuits and laminar flow air. There may be several hundred ffu in a large cleanroom, covering 100% of the ceiling area. Hence, there is of often knowledge in the inside and outside of the country the flu give rise to noise & vibration trouble to microelectronics industry. Noise ＆ Vibration control for satisfication about noise ＆ vibration criteria in TFT-LCD factory cleanroom be in need of exact noise & vibration data of accurence from utility & equipment that can be exert a bad influence upon cleanroom. In this pater, hence we found out noise and vibration properities of ffu by using experimental method. And, we performed noise ＆ vibration analysis about noise it vibration level in cleanroom using semiempirical method for quantative approach about noise ＆ vibration level in cleanroom.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.270-273
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• 2002

This paper presents an effective cutting force model that enable us to predict the instantaneous cutting force in milling process from a knowledge of the work material properties and cutting conditions. The development of the model is based on the orthogonal machining theory with the effective rake angle which is defined in the plane containing the cutting velocity and chip flow vectors. Face milling tests are performed at different feeds and, a fairly good agreement is shown between the predicted cutting forces and test results.

• Journal of the Korean Society of Visualization
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• v.9 no.3
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• pp.51-58
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• 2011

The purpose of the study is to provide a foundation in predicting a maximum wave force when the ocean structure is laid out under breaking wave. Experiments were conducted with a down-scaled cylindrical model installed in a wave generating water channel. Maximum wave slopes were changed in regular wave condition by the wave breaker in the water channel. Cylinder's diameters were changed to 0.1m and 0.05m, respectively. Using the PIV results qualitative analyses were performed based upon the previous knowledge.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1328-1333
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• 2006

For fault diagnosis of machines and equipments, knowledge-based method has been used widely but has some limitations for complex systems. These can be covered by model-based method. As one kind of model-based method, Qualitative modeling diagnosis method is developed in this research. The developed method uses output signal only. In this method quantization of the output signal mattes automata which can characterize the flow of the signal pattern to normal and fault respectively. As an example of the qualitative diagnosis method, an electric tool which has faults at gear and bearing were examined in this research. The result shows that the developed method can diagnose the fault clearly for the two fault cases.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.118-121
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• 1987

This paper presents a rule-based approach for automatically selecting critical contingencies in electric power systems. The rules required to perform the task are derived from inspection about results of simulation and expertise of operators. And inherent information of system, for example, topology of system configuration, and flow direction in a line by compensation theorem. etc., which are independent of operating point of system, is stored in the database using the off-line calculation. The approach was investigated using the study of a sample test system. Since it is based on the knowledge engineering technique, efficiency of selection can be improved by updating and adding the rules.

• The Journal of Society for e-Business Studies
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• v.7 no.2
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• pp.97-111
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• 2002

E-business curriculum needs to be developed reflecting requirements of the industry which involve a close relation with a job performed in the field, and a professional knowledge and an expert skill. In this paper, we present a method based on a market-oriented approach for developing an I-business curriculum. For the purpose, we analyze the opinion data resulting from the surveyed opinions of respondents working for I-business companies and evaluate the importance of each course being involved in the curriculum with respect to the job classification (e.g., Web planner, Web master, Web programmer, Web marketer, Web designer, Web PD), and then, complete a flow diagram considering precedence and relative difficulty among the selected courses. The E-business curriculum developed by the proposed method is useful to provide guidelines for determining courses required toward a desired job and for making a partial amendment of the curriculum.

• Nuclear Engineering and Technology
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• v.46 no.6
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• pp.753-772
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• 2014

The paper presents functional modelling and its application for diagnosis in nuclear power plants. Functional modelling is defined and its relevance for coping with the complexity of diagnosis in large scale systems like nuclear plants is explained. The diagnosis task is analyzed and it is demonstrated that the levels of abstraction in models for diagnosis must reflect plant knowledge about goals and functions which is represented in functional modelling. Multilevel flow modelling (MFM), which is a method for functional modelling, is introduced briefly and illustrated with a cooling system example. The use of MFM for reasoning about causes and consequences is explained in detail and demonstrated using the reasoning tool, the MFMSuite. MFM applications in nuclear power systems are described by two examples: a PWR; and an FBR reactor. The PWR example show how MFM can be used to model and reason about operating modes. The FBR example illustrates how the modelling development effort can be managed by proper strategies including decomposition and reuse.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.64
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• pp.213-237
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• 2014

The medical-device market of Myanmar in the recent Asian region is where the influences of Thailand, China, India and Singapore are being shown considerably with the lift-up of economic sanctions by America and the West. However, although the global capital and liberalization have widened the openness and the international concerns, the relative Myanmar's medical environment demands an active assistance and improvement. The study, recognizing the importance of Medical-Devices and their market conditions emerging as key business for knowledge-based industry, aims to obtain consequential meaningful suggestions, pursuant to relative export-concentration and sustainable market growth of Medical Devices, by analyzing inter-nation trade intensity for key Medical Device items. To do so, this study selected 8 nations in total by reviewing three points: core Medicine-advanced countries, geographically adjacent countries to Myanmar, and relative export-concentration.