• 연구논문집
• /
• s.25
• /
• pp.67-76
• /
• 1995

A grid generation algorithm associated with turbomachinery cascade flow fields has been developed. The present grid generation system consists of four separate modules. The system input is made of the results of the preliminary design, i.e., flow-path, aerodynamic conditions along the spanwise direction, and the blade profile data. The grid generation method generates a series of two-dimensional grids in the blade-to-blade passage to build up the three-¬dimensional grid, The numerical algorithm adopts the combination of the algebraic and elliptic method to create the internal grids efficiently and quickly. The resultant grids generated from each module of the system are used as the preprocessor for the performance prediction of the turbomachinery blade using Naveir-Stokes method in addition to the blade surface modelling for CAD data. For purposes of illustration, the grid generation system is applied to several complex geometries inculding a turbine rotor with and without a tip flow grid. Application to the blade design of the LP compressor was demonstrated to be very reliable and practical in support of design activities. This customized system are coupled strongly with the design procedure and reduces the man-hours required to predict the aerodynamic performance of the turbomachinery cascades using the CFD technique.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.1376-1379
• /
• 2006

Vibro crushed-stone compacted pile (VCCP) method is one of a ground improvement technique by a vibro compaction in vertical direction with crushed stone to build up stone pile foundation in other to ensure stability of soft ground. In spite of its long applied history in geotechnical engineering division, most of studies have not been based on the reliable In-situ condition but on the laboratory tests including model tests. These model tests can express standard and ideal behavior but exceptional status that can be occur in the ground cannot be considered efficiently. This study performed the the series of trial construction to investigate the effect of VCCP method on the improvement of soft ground expecially in railroad construction site.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.23 no.3
• /
• pp.270-279
• /
• 2003

Parametric studies have been conducted into the variability of the factors affecting the ultrasonic testing applied to weldments. The influence of ultrasonic equipment, transducer parameters, test technique, job parameters, defect type and characteristics on reliability far defect detection and sizing was investigated by experimentation. The investigation was able to build up substantial bank of information on the reliability of manual ultrasonic method for testing weldments. The major findings of the study separate into two parts, one dealing with correlation between ultrasonic techniques, equipment and defect parameters and inspection performance effectiveness and other with human factors. Defect detection abilities are dependent on the training, experience and proficiency of the UT operators, the equipment used, the effectiveness of procedures and techniques.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.47.4-47
• /
• 2001

The automatic-driverless operation, a very important technique for metro railways, is necessary for achieving higher safety, greater reliability, and bigger transport capacity. To achieve these things, we have to build up the system design and tasting techniques for the railway system operation. These techniques are related to the onboard train control and communication systems which include TCMS(Train Control and Monitoring System), ATO(automatic train Operation), ATC(Automatic train Control), and TWC(Train to wayside communication). These sub-systems should interface not only with each other but also between the sub-systems and the signal system on the ground. For the saving of energy, we designed coasting strategy of ATO system, In this paper, we developed ATO system and tested on the test line and ...

• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.1410-1413
• /
• 2009

A city development has been focused on solving a housing shortage of city resulted from rapid industrialization and population increase in city. However, such a development has caused many problems in environment, economy, safety, and so on. In recent, therefore, a new paradigm of a city development is required, and thus ubiquitous city (U-City) concept appears. U-City development, which combines construction method and IT technique, creates a new composite space, and help people improve quality of life in terms of solving many problems caused by existing method of a city development. However, there is no guide to build U-City up to date, and most present U-City projects have processed following past method of city development. Therefore, an objective of this paper is to suggest an explicit procedure of enforcement design in U-City system.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.4
• /
• pp.487-493
• /
• 2012

SLAM(Simultaneous Localization And Mapping) is a technique used by robots and autonomous vehicles to build up a map within an unknown environment and estimate a place of robot. FastSLAM(A Factored Solution to the SLAM) is one of representative method of SLAM, which is based on particle filter and extended Kalman filter. However it is suffered from loss of particle diversity. In this paper, new approach using fitness sharing is proposed to supplement loss of particle diversity, compared and analyzed with existing methods.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.771-774
• /
• 2000

RP techniques have inherent disadvantages caused by their working principles: stair-stepped surface of parts due to layer-by-layer stacking of layers, low build speed caused by line-by-line solidification to finish one layer, and post processing to improve surface finish, etc. The objective of this study is to propose a new RP technique, variable deposition manufacturing (VDM), which can make up for the disadvantages of the existing RP techniques, and to develop an apparatus to implement the technique. The proposed process can greatly reduce the building time and improve the surface finish of parts generated. The experiments are carried out to obtain the range of temperature of molten material to maintain its fluidity and to investigate the effect of gas cooling on the preservation of the slopes. Based on the results, some simple shapes such as a line-shape. an S-shape, and a circle-shape were fabricated from Ethylene Vinyl Acetatecopolymer (EVA). In order to examine the applicability of VDM to more general shapes, a tensile specimen and a yo-yo shape were manufactured by the proposed RP method using EVA material as the first trial approach. The present basic study has shown the possibility of a practicable utilization of the proposed VDM process to prototyping of a general three-dimensional shape.

• Journal of Institute of Control, Robotics and Systems
• /
• v.4 no.4
• /
• pp.525-533
• /
• 1998

A conventional contact type brake system which uses a hydraulic system has mny Problems such as time delay response due to pressure build-up, brake pad wear due to contact movement, bulky size, and low braking performance in high speed region. As vehicle speed increases, a more powerful brake system is required to ensure vehicle safety and reliability. In this work, a contactless brake system of an eddy current type is proposed to overcome problems. Optimal torque control which minimizes a braking distance is investigated with a scaled-down model of an eddy current type brake. It is possible to realize optimal torque control when a maximum friction coefficient (or desired slip ratio) corresponding to road condition is maintained. Braking force analysis for a scaled-down model is done theoretically and experimentally compensated. To accomplish optimal torque control of an eddy current type brake system, a sliding mode control technique which is, one of the robust nonlinear control technique is developed. Robustness of the sliding mode controller is verified by investigating the braking performance when friction coefficient is varied. Simulation and experimental results will be presented to show that it has superior performance compared to the conventional method.

• International Journal of Computer Science & Network Security
• /
• v.23 no.6
• /
• pp.115-120
• /
• 2023

Plant leaf diseases and destructive insects are major challenges that affect the agriculture production of the country. Accurate and fast prediction of leaf diseases in crops could help to build-up a suitable treatment technique while considerably reducing the economic and crop losses. In this paper, Convolutional Neural Network based model is proposed to detect leaf diseases of a plant in an efficient manner. Convolutional Neural Network (CNN) is the key technique in Deep learning mainly used for object identification. This model includes an image classifier which is built using machine learning concepts. Tensor Flow runs in the backend and Python programming is used in this model. Previous methods are based on various image processing techniques which are implemented in MATLAB. These methods lack the flexibility of providing good level of accuracy. The proposed system can effectively identify different types of diseases with its ability to deal with complex scenarios from a plant's area. Predictor model is used to precise the disease and showcase the accurate problem which helps in enhancing the noble employment of the farmers. Experimental results indicate that an accuracy of around 93% can be achieved using this model on a prepared Data Set.

• International Journal of Computer Science & Network Security
• /
• v.24 no.4
• /
• pp.107-112
• /
• 2024

Plant leaf diseases and destructive insects are major challenges that affect the agriculture production of the country. Accurate and fast prediction of leaf diseases in crops could help to build-up a suitable treatment technique while considerably reducing the economic and crop losses. In this paper, Convolutional Neural Network based model is proposed to detect leaf diseases of a plant in an efficient manner. Convolutional Neural Network (CNN) is the key technique in Deep learning mainly used for object identification. This model includes an image classifier which is built using machine learning concepts. Tensor Flow runs in the backend and Python programming is used in this model. Previous methods are based on various image processing techniques which are implemented in MATLAB. These methods lack the flexibility of providing good level of accuracy. The proposed system can effectively identify different types of diseases with its ability to deal with complex scenarios from a plant's area. Predictor model is used to precise the disease and showcase the accurate problem which helps in enhancing the noble employment of the farmers. Experimental results indicate that an accuracy of around 93% can be achieved using this model on a prepared Data Set.