• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.10 s.175
• /
• pp.90-98
• /
• 2005

A monitoring system is necessary to make the polishing process more reliable in order to ensure the high quality and performance of the final products. Generally, AE (Acoustic Emission) is known to be closely related to the material removal rate (MRR). As the surface becomes rougher, the MRR and AE increase. Therefore, the surface roughness can be indirectly estimated using the AE signal measured during the polishing. In this study, an AE sensor-based monitoring system was fabricated to detect the very small AE signal resulting from the friction between a tool and a workpiece during polishing. The performance of this monitoring system was estimated according to polishing conditions, the relation between the level of the AE RMS and the surface roughness during the polishing was investigated.

• Journal of the Semiconductor & Display Technology
• /
• v.6 no.3
• /
• pp.1-6
• /
• 2007

The integrated thermal-chemical-mechanical (TCM) material removal model presented in the companion paper is dynamically simulated in this work. The model is applied to a Cu CMP process for the simulation and the results of the three individual ingredients composing the model are presented separately first. These results are then incorporated to calculate the total material removal rate (MRR) of the Cu CMP. It is shown that the non-linear trend of MRR with respect to the applied mechanical power (i.e., non-Prestonian behavior), which is not well explained with the models established in principle on conventional contact mechanics, may be due to the chemical reaction(s) varying non-linearly with the temperature in the wafer.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.2B
• /
• pp.69-75
• /
• 2008

We propose new routing scheme, Cooperative Diversity-based Routing (CDR)which utilize the cooperative space diversity for power saving and for performance enhancement of wireless ad-hoc networks. The end-to-end performance of the proposed routing, CDR, is analyzed based on the Haenggi's link model. The improved performance is compared with Multi-hop Relay Routing (MRR) by analytical methods. When the required outage probability is $1{\times}10^{-3}$ at the destination node in ad-hoc networks with 7 nodes, we noticed that each node can save power consumption by 21.5 dB in average, by using our proposed CDR compared to MRR.

• Annual Conference on Human and Language Technology
• /
• 2023.10a
• /
• pp.295-300
• /
• 2023

대화 데이터와 같은 데이터는 사람이 수작업으로 작성해야 하기 때문에 데이터셋 구축에 시간과 비용이 크게 발생한다. 현재 대두되고 있는 Large Language Model은 이러한 대화 생성에서 보다 자연스러운 대화 생성이 가능하다는 이점이 존재한다. 이번 연구에서는 LLM을 통해 사람이 만든 적은 양의 데이터셋을 Fine-tuning 하여 위키백과 문서로부터 데이터셋을 만들어내고, 이를 통해 문서 검색 모델의 성능을 향상시켰다. 그 결과 학습 데이터와 같은 문서집합에서 MRR 3.7%p, 위키백과 전체에서 MRR 4.5%p의 성능 향상을 확인했다.

• Tribology and Lubricants
• /
• v.33 no.5
• /
• pp.214-219
• /
• 2017

Abrasive fluidized bed machining (AFBM) is similar to general abrasive fluidized machining (AFM) in that it can perform polishing of the outer and inner surfaces of a 3-dimensional shape by the flow of particles. However, in the case of AFM, the shear force generated by the flow of the particles causes material removal, while in AFBM, the abrasive particles are suspended in the chamber to form a bed. AFBM can be used for deburring, polishing, edge contouring, shot peening, and cleaning of mechanical parts. Most studies on AFBM are limited to metals, and research on application of AFBM to plastic materials has not been performed yet. Therefore, in this study, we investigate the effect of rotating speed of the specimen and the air flow rate on the material removal characteristics during AFBM of polyacetal with a horizontal AFBM machine. The material removal rate (MRR) increases linearly with increase of the rotating speed of the main shaft because of the shear force between the particles of the fluidized bed and the rotation of the workpiece. The reduction in surface roughness tends to increase as the rotating speed of the main shaft increases. As the air flow rate increases, the MRR tends to decrease. At a flow rate of 70 L/min or more, the MRR remains almost constant. The reduction of the surface roughness of the specimen is found to decrease with increasing air flow rate.

• Korean journal of applied entomology
• /
• v.50 no.2
• /
• pp.97-105
• /
• 2011

Understanding the metapopulation structure and movement of a species are required for conserving the species. In this paper, migration patterns and connectivity of patches of a threatened butterfly, Parnassius bremeri Bremer, were postulated using the mark-release-recapture (MRR) technique in a habitat located in the mid-southern region of the Korean peninsula. A total of 194 individuals were captured (137 males and 57 females) and, of them, 93 individuals (73 males and 20 females) were recaptured during the MRR experiment. The migration analysis showed 23-150% immigration and 28-53% emigration. There were high correlations between the migrating individuals and the distance between patches, but there was no correlation between migrating individuals and patch size or between migrating individuals and the number of host plants. Consequently, the migration of butterflies occurred frequently between closer patches, while patch size and quantity of the food plant had minor effects on migration behavior. Additionally, males migrated more frequently than females. Analysis of the migration patterns of P. bremeri showed that the central patch played an important role on linking patch groups and more frequent migrations were monitored between nearby patches than between the remote patches. This study suggested that active migrations take place between the neighboring multiple patches and these are accelerated if there is a stepping-stone patch between them.

• Journal of Korean Society of Archives and Records Management
• /
• v.22 no.4
• /
• pp.25-43
• /
• 2022

The ultimate record management's purpose is preservation and utilization. However, the National Archives of Korea (NAK)s Portal has problems such as search system aging and search tools dualization. As a result, the users' search satisfaction is not satisfied, and the improvement demand increases. This study aimed to evaluate the NAK's search quality as a preliminary study for NAK search system advancement. To this end, we analyzed the current status of CAMS and NAK's Portal. Then, we established the test sets and evaluated the NAK's Portal quality from the user's point of view. Evaluation results were analyzed using Precision, Recall, F-score, and MRR. The analysis results showed that the overall search performance was low, particularly in the "advanced subject search," which showed low performance in Precision, Recall, and MRR. Thus, improvement is urgently needed. The test sets established for this study are expected to be used as a basis for objectively measuring the improvement of the search performance after the NAK search system advancement.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2001.06a
• /
• pp.500-505
• /
• 2001

본 논문에서는 웨이브릿 변환 영역에서의 디지털 워터마킹 기법을 제안한다. 영상을 2계층의 웨이블릿 변환 영역으로 변환하여 영상압축에 견고한 저주파대역(MRA)과 인간 시각에 덜 민감한 고주파 대역(MRR)에 각각 이진 도장 영상으로 된 워터마크를 첨가한다. 잡음이나 공격으로 영상이 훼손된 경우라도 다른 대역에서 워터마크를 추출하여 소유권을 주장할 수 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.95-96
• /
• 2009

• Proceedings of the Optical Society of Korea Conference
• /
• 2009.10a
• /
• pp.388-389
• /
• 2009