• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.1
• /
• pp.138-144
• /
• 2008

Micro-machining of a brittle material such as glass, silicon, etc., is important in micro fabrication. Particularly, micro-abrasive jet machining (${\mu}-AJM$) has become a useful technique for micro-machining of such materials. The ${\mu}-AJM$ process is mainly based on the erosion of a mask which protects brittle substrate against high velocity of micro-particle. Therefore, fabrication of an adequate mask is very important. Generally, for the fabrication of a mask in the ${\mu}-AJM$ process, a photomask based on the semi-conductor fabrication process was used. In this research a rapid mask fabrication technology has been developed for the ${\mu}-AJM$. By scanning the focused UV laser beam, a micro-mask pattern was fabricated directly without photolithography process and photomask. Two kinds of mask patterns were fabricated using SU-8 and photopolymer (Watershed 11110). Using fabricated mask patterns, abrasive-jet machining of Si wafer were conducted successfully.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.05a
• /
• pp.535-536
• /
• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.10a
• /
• pp.503-504
• /
• 2006

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2005.06a
• /
• pp.121-125
• /
• 2005

• Journal of Broadcast Engineering
• /
• v.18 no.3
• /
• pp.474-480
• /
• 2013

In orthogonal frequency division multiplexing system (OFDM), rapid channel variation caused by fast moving receiver leads to a loss of subcarrier orthogonality which results in inter-carrier interference (ICI) and receiver performance degradation. In conventional receivers, performance is enhanced by estimating ICI and removing it from received signals. In this paper, an ICI reduction scheme using a time-domain mask and adding is proposed. The proposed scheme is applied to DVB-T receiver to prove the Doppler mobile performance enhancement.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2007.06a
• /
• pp.139-143
• /
• 2007

The need for technological developments of lithography equipment is urgent for the stable production in response to the rapid growth of the recent display industry. As an example, the products currently in the market face alteration problems resulting from excessive weight of the mask holder part. This is one of obstacle for the automation of the equipment. In response, the mask holder part problem has been minimized through FEM and design of experiments in order to optimize the situation with minimized Deflection and reduced mass for satisfactory replacement of the mask holder part.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.45 no.2
• /
• pp.167-172
• /
• 2012

Minerals from marine materials such as deep ocean water and Dead Sea water have been used since ancient times. We made a mask pack sheet including deep ocean water and salt from the Dead Sea and evaluated the function of the mask pack sheet through animal study. Three full-thickness skin defects were made on the backs of Sprague-Dawley rats. The wounds were left untreated in group Con, and mask pack sheets including deep ocean water or deep ocean water and Dead Sea water were used as treatment for 20 min on the skin of animals in groups DP and DDP, respectively. We analyzed the gross, histological and biochemical findings. Groups DDP and DP showed decreases in wound size, as compared to group Con at 7 days after wound infliction. The histological findings revealed that wound healing had progressed further in groups DP and DDP than in group Con, with more rapid collagen deposition and regression of neutrophils. Also, the expression of vascular endothelial growth factor and transforming growth factor ${\beta}1$ were increased in groups DDP and DP compared with those in group Con at 3 days after wound infliction. Mask sheet packs including deep ocean water and Dead Sea salt affected wound healing by reducing the inflammatory phase and stimulated wound contracture by facilitating the deposition of collagen.

• Journal of Internet Computing and Services
• /
• v.20 no.5
• /
• pp.105-111
• /
• 2019

Core technologies that lead the Fourth Industrial Revolution era, such as artificial intelligence, big data, and autonomous driving, are implemented and serviced through the rapid development of computing power and hyper-connected networks based on the Internet of Things. In this paper, we implement two different models for drivable area segmentation in various environment, and propose a better model by comparing the results. The models for drivable area segmentation are using DeepLab V3+ and Mask R-CNN, which have great performances in the field of image segmentation and are used in many studies in autonomous driving technology. For driving information in various environment, we use BDD dataset which provides driving videos and images in various weather conditions and day&night time. The result of two different models shows that Mask R-CNN has higher performance with 68.33% IoU than DeepLab V3+ with 48.97% IoU. In addition, the result of visual inspection of drivable area segmentation on driving image, the accuracy of Mask R-CNN is 83% and DeepLab V3+ is 69%. It indicates Mask R-CNN is more efficient than DeepLab V3+ in drivable area segmentation.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.6
• /
• pp.67-77
• /
• 2022

The purpose of this study was to explore the experiences of counselors who conducted video counseling using digital mask. To this end, the contents of the focus group interview with four counselors who experienced mask video counseling for a total of 10 Korean college student clients were analyzed using thematic analysis method. Participant counselors reported that they had been concerned about mask video counseling before the start but gradually be adjusted to the method. Since they have observed the rapid self-disclosure of the clients and smooth counseling process, they positively predicted the possibility of digital masks as a therapeutic media. They also mentioned the need for additional education and training for the counselors who are using the new on-line counseling media. Therefore, various supports for proactive responses of counselors to online counseling media need to be explored.

• Korean Journal of Materials Research
• /
• v.16 no.3
• /
• pp.151-156
• /
• 2006

A method for fabrication of nano-scale GaN structure by inductively coupled plasma etching is proposed, exploiting a thermal dewetting of Pt thin film as an etch mask. The nano-scale Pt metal islands were formed by the dewetting of 2-dimensional film on $SiO_2$ dielectric materials during rapid thermal annealing process. For the case of 30 nm thick Pt films, pattern formation and dewetting was initiated at temperatures greater $600^{\circ}C$. Controlling the annealing temperature and time as well as the thickness of the Pt metal film affected the size and density of Pt islands. The activation energy for the formation of Pt metal island was calculated to be 23.2 KJ/mole. The islands show good resistance to dry etching by a $CF_4$ based plasma for dielectric etching indicating that the metal islands produced by dewetting are suitable for use as an etch mask in the fabrication of nano-scale structures.