• Journal of the Korean Society for Precision Engineering
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• v.22 no.1
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• pp.199-206
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• 2005

Mask manufacturing is a high COC and COO process in developing of semiconductor devices because of mask production tool with high resolution. Direct writing has been thought to be the one of the patterning method to cope with development or small-lot production of the device. This study consists two categories. One is the additional process of the direct and maskless patterning generation using SLA for easy and convenient application and the other is a removal process using wet-etching process. In this study, cured status of epoxy pattern is most important parameter because of the beer-lambert law according to the diffusion of UV light. In order to improve the contact force between patterns and substrate, prime process was performed and to remove the semi-cured resin which makes a bad effects to the pattern, spin cleaning process using TPM was also performed. At a removal process, contact force between photo-curable resin as an etching mask and Si wafer is important parameter.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.824-828
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• 2000

As production cycle has become more and more shorter, the demand of rapid prototyping technology has increased largely. There are many methods for rapid prototyping technology, such as SLA. SLS, FDM. INK JET, LOM and so on. Of all methods, SLA has been most widely used for fabricating precision parts. But products manufactured by this method have limitation of single color and single material. So the principal purpose of this study is to overcome the limit of single color product. If the internal structure of manufactured product is visible with multi-color characteristic, it is possible to check easily the designed model with reality. In order to give multi-color characteristic to the product, photocurable resin mixed with pigment is used in this study. First, transparency of photocurable resin without pigment is evaluated, and then color characteristic and curing characteristic of the mixture is evaluated changing mixing ratio. Through the basic experiments, it becomes possible to fabricate multi-color 3D prototype without assembly.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.146-154
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• 1996

In this work, rapid prototyping and three-dimensional finite element analysis are simultaneously applied to the die design of metal forming processes. Rapid prototyping is a new prototyping technology which produces three-dimensional part models directly from CAD data and has been extensively applied to various manufacturing processes. There are many types of rapid prototyping systems due to their building principles and materials. In this work, Stereolithography Apparatus(SLA), which is the most widely used rapidprototyping system, is introduced to manufacture the die set. For general preparation of STL file, which is the standard input file of rapid prototyping system, mesh data which are used in describing the die surface in finite element analysis are translated so that rapid prototyping and finite element analysis are dffectively connected. A die set for spider forging and a clover punch for deep drawing section are manufactured effciently using SLA prototypes, and metal forming experiments are carried out using them. Comparing the result of experiments with that of analyses, the processes can be predicted and designed successfully.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.219-221
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• 2009

This paper analyzes efficiency of photovoltaic(PV) tracking system using solar location algorithm(SLA). Solar location tracking system is needed for efficiently and intensively using PV system independent of environmental condition. PV tracking system of program method is presented a high tracking accuracy without the wrong operating in rapidly changed insolation by the clouds and atmospheric condition. Therefore, this paper analyzes efficiency of PV system using SLA for more correct position tracking of solar. Also, controlled altitude angle and azimuth angle by applied algorithm is compared with data of korea astronomy observatory. And this paper analyzes the tracking error and proves the validity of applied algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.735-737
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• 2016

In this paper, we conducted a test of the 3D printer injection method and LSU (Laser Scanning Unit) feature a fusion of the polygon mirror scanning system that is the core mechanism operation for 3D printers for office laser printers SLA system. These tests ensure that the laser was operating and control well was confirmed that a certain point is output to the X-axis by means of a laser module and a polygon mirror. And confirmed after the F-theta lens is incident on the fixed laser power of the beam, and correction according to the correction beam on the mirror reflection was confirmed jineunji the focus according to the Z-axis upper plate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1B
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• pp.86-100
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• 2004

To provide the end-to-end service differentiation for assured services, the random early demotion and promotion (REDP) marker in the edge router at each domain boundary monitors the aggregate flow of the incoming in-profile packets and demotes in-profile packets or promotes the previously demoted in-profile packets at the aggregate flow level according to the negotiated interdomain service level agreement (SLA). The REDP marker achieves UDP fairness in demoting and promoting packets through random and early marking decisions on packets. But, TCP fairness of the REDP marker is not obvious as for UDP sources. In this paper, to improve TCP fairness of the REDP marker, we propose a modified REDP marker where we combine a dropper, meters and a token filling rate configuration component with the REDP marker. To make packet transmission rates of TCP flows more fair, at the aggregate flow level the combined dropper drops incoming excessive in-profile packets randomly with a constant probability when the token level in the leaky bucket stays in demotion region without incoming demoted in-profile packets. Considering the case where the token level cannot stay in demotion region without the prior demotion, we propose a token filling rate configuration method using traffic meters. By using the token filling rate configuration method, the modified REDP marker newly configures a token filling rate which is less than the negotiated rate determined by interdomain SLA and larger than the current input aggregate in-profile traffic rate. Then, with the newly configured token filling rate, the token level in the modified REDP marker can stay in demotion region pertinently fir the operation of the dropper to improve TCP fairness. We experiment with the modified REDP marker using ns2 simulator fur TCP sources at the general case where the token level cannot stay in demotion region without the prior demotion at the negotiated rate set as the bottleneck link bandwidth. The simulation results demonstrate that through the combined dropper with the newly configured token filling rate, the modified REDP marker also increases both aggregate in-profile throughput and link utilization in addition to TCP fairness improvement compared to the REDP marker.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.142-144
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• 2016

Recent promising technologies of the manufacturing sector interest, and the interest in 3D printing that is expected to cause a huge ripple effect rapidly, and various types of products advertised in accordance with the falling price of 3D printers is spreading. However, the personal 3D printers that are currently being advertised is used for Injection output of the simple type that does not require a high processing precision in accordance with the limitation of technical performance, and consumer satisfaction is very low. In this paper, we propose a 3D printer, 3D precision to overcome existing limitations in the way the printer's high SLA 3D printer that combines injection method and the LSU (Laser Scanning Unit) in the office laser printer polygon mirror scanning method. 3D printers which are proposed to improve the accuracy and manufacturing speed is expected to replace the existing entry-level 3D printer.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.3
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• pp.153-162
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• 2016

This paper proposes an optimal dynamic resource allocation method in IoT (Internet of Things) parking guidance system using Q-learning resource allocation model. In the proposed method, a resource allocation using a forecasting model based on Q-learning is employed for optimal utilization of parking guidance system. To demonstrate efficiency and availability of the proposed method, it is verified by computer simulation and practical testbed. Through simulation results, this paper proves that the proposed method can enhance total throughput, decrease penalty fee issued by SLA (Service Level Agreement) and reduce response time with the dynamic number of users.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.343-349
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• 1993

This study was conducted 1)to determine the factors responsible for the gradually increased rice yield by examining any improvements in yield-related characters and physiological characters among the historically recommended varieties of rice in Korea, and 2)to reveal the way of achieving further yield improvement by breeding in the future. Eight recommended varieties from 1911 to 1988 were selected and grown at the same conditions. The yield-related characters were observed at the harvest time, and the physiological characters such as RGR, NAR, LAR, SLA and L WR were estimated by the classical method of growth analysis. The newer varieties are shorter and those released after 1970's are greater in percent of filled spikelets and harvest index than the older varieties. There are no definite changing trends in the variations of number of panicles per hill, number of spikelets per panicle and 1000 grain weight according to the course of evolution in the recommended varieties. There is little evidence of improvement in the physiological characters such as NAR, LAR, SLA and LWR among the recently developed varieties compared with those of the older varieties. The increase in grain yield due to variety improvement, if any, is largely associated with the greater harvest index and percent of filled spikelets by breeding blight resistant and / or lodging resistant genotypes with short culm. It is suggested that increase in NAR should be carried out simultaneously with increase in harvest index to breed high yielding genotypes. I t appears to be important to breed genotypes with long culm in order to enhance light penetration into the canopy as long as they are lodging resistant. Since NAR is negatively correlated with LAR, it is unlikely to succeed to improve both characters simultaneously. The direct effect of NAR on RGR by path analysis is much larger than that of LAR, and hence it is suggested that breeding genotype with large NAR is more effective on enhancing RGR. It is also suggested that improving LAR through LWR is likely effective on increasing RGR.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.503-507
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• 2002

Mask manufacturing is a high COC and COO process in developing of semiconductor devices, because of the mass production tool with high resolution. Direct writing has been thought to be one of the patterning method to cope with development or small-lot production of the device. This study focused on the development of the direct, mastless patterning process using stereolithography tool for the easy and convenient application to micro and miso scale products. Experiments are utilized by three dimensional CAD/CAM as a mask and photo-curable resin as a photo-resist in a conventional stereo-lithography apparatus. Results show that the resolution of the pattern was achieved about 300 micron because of complexity of SLA apparatus settings, inspite of 100 micro of inherent resolution. This paper concludes that photo resist and laser spot diameter should be adjusted to get finer patterns and the proposed method is significantly feasible to mastless and low cost patterning with micro and miso scale.