• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.8-15
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• 2005

A new measuring method for tool deflection has been developed when sculptured surface is processed in ball-end milling. Since the vibration due to cutting forces has low frequencies, an electromagnetic sensor is used for measuring the exact vibration displacement. The amplitude and direction of vibration displacement during the cutting process is presented as orbital plot. In this study, it assumes that the vibration displacement is proportional to the length of cutting chip. Therefore, tool deflection is calculated by summing up the vibration displacement of unit chip length for engaged chip length. In addition, computer programs has been developed to predict the deflection of tools when machining sculptured surface. This developed program predicts the tool deflection per block of NC data, so that it can easily identify the parts which have the possibility of machining errors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1054-1058
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• 1995

There have been many research works for the indirect cutting force measurement in machining process, which deal with the case of one-axis cutting process. In multi-axis cutting process, the main difficulties to estimate the cutting forces occur when the feed direction is reversed. This paper presents the indirect cutting force measurement method in contour NC milling processes by using current signals of servo motors. An artificial neural network (ANN) system are suggested. An artificial neural network(ANN) system is also implemented with a training set of experimental cutting data to measure cutting force indirectly. The input variables of the ANN system are the motor currents and the feedrates of x and y-axis servo motors, and output variable is the cutting force of each axis. A series of experimental works on the circular interpolated contour milling process with the path of a complete circle has been performed. It is concluded that by comparing the ANN system with a dynamometer measuring cutting force directil, the ANN system has a good performance.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.7
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• pp.85-93
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• 1999

In this study, PC-based slicing machine and driving software were constructed for the purpose of automation of semi-conductor cutting process. The biggest feature of software is variation of parameter and include data base, signal monitoring, error report, corresponding action or automatic motion planing. Parameters were drawn and algorithms were developed to make software by GUI interface. The cutting experiment was done for sampled wafer to see the effectiveness of the soft automation. From the experimented and implemented results, it is shown that parameters for automation of slicing process could be drawn, then its algorithms constructed. It could be considered what is the merit of this slicing machine by comparing the PC-based and the NC-based.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1146-1149
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• 1995

The CAD/CAM System for deep drawing transfer die in mechanical press proess has been developed. The developed CAD system can generate the drawing of drawing of transfer die in mechanical press. Using these results from CAD system, it can generate the NC data to machine die's elements on the CAD system. This system can reduce design man-hours and human errors. In order to construct the system, it is used to automate the design process using knowledge base system. The developed system is based on the knowledge base system which is involved a lot of expert's technology in the practice filed. Using AutoLISP language under the AutoCAD system, CTK customer language of SmartCAM is used as the overall CAD/CAM environment. Results of this system will be provide effective aids to the designer and mannufacturer in this field.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1103-1108
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• 2009

The human immunodeficiency virus (HIV)-l protein Tat acts as a transcription transactivator that stimulates expression of the infected viral genome. It is released from infected cells and can similarly affect neighboring cells. The nucleocapsid is an important protein that has a related significant role in early mRNA expression, and which contributes to the rapid viral replication that occurs during HIV-1 infection. To investigate the interaction between the Tat and nucleocapsid proteins, we utilized cDNA micro arrays using pTat and flag NC cotransfection in HEK 293T cells and reverse transcription-polymerase chain reaction to validate the micro array data. Four upregulated genes and nine downregulated genes were selected as candidate genes. Gene ontology analysis was conducted to define the biological process of the input genes. A proteomic approach using PathwayStudio determined the relationship between Tat and nucleocapsid; two automatically built pathways represented the interactions between the upregulated and downregulated genes. The results indicate that the up- and downregulated genes regulate HIV-1 replication and proliferation, and viral entry.

• KIEAE Journal
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• v.14 no.4
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• pp.11-18
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• 2014

Although assessing outdoor environment and green space in terms of sustainability and environmental performance is perceived as an important issue, most existing green building certification systems are more focused on buildings and indoor environment. Recently, the Sustainable Site Initiatives (SITES) has been developed by American Society of Landscape Architecture in order to evaluate sustainability of site development and outdoor environment. Separate from LEED, the SITES are increasingly receiving attentions as a reliable certification system in the United States. As a preliminary study to develop the items of outdoor environmental assessment, the present study is purposed to analyze the assessment items, grading system and applicability of SITES for better understanding on the system. Also it was compared to existing green building certification criteria, including G-SEED, LEED-NC, and LEED-ND in order to investigate similarities and discrepancies. The results would provide insights and basic data to improve assessment items for outdoor environment of G-SEED.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1024-1030
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• 1993

In manufacturing press die with free surface, grinding operation is an important post process for surface finish and dimensional accuracy. With the advancement of NC technology. surface grinding operation is increasingly replaced by the gantry type manipulator. As the mechanics for grinding operation is different from machining operation, conventional CAM system for machining operation is hard to apply. In this. paper, we develop a five-axis CAM system by which an efficient gantry trajectory can be planned and verified. The developed system consists of four conceptual modules; namely CAD, PROCESS. CAM, and ANALYSIS. In the CAD module, the machined surface is represented by CL-data or surface modeler, and process parameters are specified by the PROCESS module. Then, the CAM module generates a series of grinding paths based on the grinding mechanics together with process databases for tool spaces and grinding conditions. The generated paths are verified via ANALYSIS module. Validation via real experiments is left for further study.

• International Journal of Internet, Broadcasting and Communication
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• v.5 no.2
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• pp.11-14
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• 2013

This paper describes the sigma-delta ADC/DAC digital block with two channels. The ADC block has comb filter and three half band filters. And the DAC block has 5th Cascaded-of-Integrators Feedback DSM. The ADC and DAC support I2S, RJ, LJ and selectable input data modes of 24bit, 20bit, and 16bit. It is fabricated with 0.35um Hynix standard CMOS cell library. The chip size is 3700*3700um. It has been verified using NC Verilog Simulator and Matlab Tool.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.278-282
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• 1997

Thermal expension of the ball screw in semi-closed loop type CNC Lathe directly introduces positioning error along the travel axis. In this paper the thermal displacement of the ball screw is estimated by using macro variabie. The estimated dispacement of the ball screw are given to the NC in the form of pitch error compensation data into time interval. The thermal behaviour of the ball screw of the CNC Lasthe under the constant driving conditions was measured to examine the effectiveness of this compensation method. The results showed that thermal displacment of the ball screw were the positioning accuracy could be maintained to better then 6 .mu.m while using this compensation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.133-136
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• 2003

In these days, the reliability analysis and prediction are applied for many industrial products and many products require guaranteeing the quality and efficiency of their products. In this study reliability prediction for core units of machine tools has been performed in order to improve and analyze its reliability. ATC(Automatic Tool Changer) and interface Card of PC-NC that are core component of the machine tools were chosen as the target of the reliability prediction. A reliability analysis tool was used to obtain the reliability data(failure rate database) for reliability prediction. It is expected that the results of reliability prediction be applied to improve and evaluate its reliability. Failure rate, MTBF (Mean Time Between Failure) and reliability for core units of machine tools were evaluated and analyzed in this study.