• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.1-7
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• 2012

In this paper, we design and implement the simulator for WAN storage replication model performance evaluation in cloud computing environment. Each cloud of simulator is composed of virtual machine emulator and storage emulator. The virtual machine emulator is composed of read/write ratio module, the read/write sequence combination module, and the read/write request module. The storage emulator is composed of storage management module, data transfer module, read/write operations module, and overhead processing module. Using the simulator, we evaluate performance of migration scheme, pre-copy and the post-copy, considering about read/write ratio, network delay, and network bandwidth. Through simulation, we have confirmed that the average migration time of pre-copy was decreased proportional to the read operation. However, average migration time of post-copy was on the increase. Also, the average migration time of post-copy was increased proportional to the network delay. However, average migration time of pre-copy was shown uniformly. Therefore, we show that pre-copy model more effective to reduce the average migration time than the post-copy model. The average migration time of pre-copy and post-copy were not affected by the change of network bandwidth. Therefore, these results show that selects the storage replication model to be, the network bandwidth know not being the important element.

• Journal of Communications and Networks
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• v.9 no.1
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• pp.43-49
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• 2007

The implementation of client polling as a weak cache coherence mechanism has two major drawbacks: Firstly, the cache may return a stale copy if the object is changed in the origin server while the cached copy is considered valid. Secondly, the cache can invalidate a cached copy that is still valid in the server. Therefore, we propose a multilevel pre-fetching (MLP) in conjunction with the client polling to refine these drawbacks. MLP is introduced to improve the level of freshness among the cached objects. The simulation results presented in this paper show that the proposed MLP significantly minimizes the number of stale objects and reduces the invalidation messages sent out to the server, i.e., increase the cache HIT rate.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.15-16
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• 2011

본 논문에서는 클라우드 컴퓨팅 환경에서 저장공간 이주(storage migration)시에 저장공간의 읽기/쓰기 비율을 고려한 저장공간 복제 모델 선정을 위한 실험 환경을 설계한다. 기존의 저장공간 이주 모델은 가상머신과 저장공간중에 저장공간이 먼저 이주하는 선복제(pre-copy)와 나중에 이주하는 후복제(post-copy)가 있다. 이러한 복제 기법은 VM과 저장공간 이주의 필요성과 그 방법만을 제안하였으며, 성능 향상을 위한 이주 기법 선정 방법은 제시하지 못하였다. 따라서 본 논문에서는 클라우드 컴퓨팅 환경에서 다양한 스토리지의 읽기/쓰기 비율에 따른 이주 모델 선정 기법을 실험할 수 있는 시뮬레이터 설계 방법을 제시한다.

• Journal of Information Processing Systems
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• v.12 no.3
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• pp.502-510
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• 2016

Considering video copy transform diversity, a multi-feature video copy detection algorithm based on a Speeded-Up Robust Features (SURF) local descriptor is proposed in this paper. Video copy coarse detection is done by an ordinal measure (OM) algorithm after the video is preprocessed. If the matching result is greater than the specified threshold, the video copy fine detection is done based on a SURF descriptor and a box filter is used to extract integral video. In order to improve video copy detection speed, the Hessian matrix trace of the SURF descriptor is used to pre-match, and dimension reduction is done to the traditional SURF feature vector for video matching. Our experimental results indicate that video copy detection precision and recall are greatly improved compared with traditional algorithms, and that our proposed multiple features algorithm has good robustness and discrimination accuracy, as it demonstrated that video detection speed was also improved.

• The Korean Journal of Applied Statistics
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• v.24 no.5
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• pp.847-859
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• 2011

cDNA microarray-based comparative genomic hybridization(CGH) data includes low-intensity spots and thus a statistical strategy is needed to detect subtle differences between different cancer classes. In this study, genes displaying a high frequency of alteration in one of the different classes were selected among the pre-selected genes that show relatively large variations between genes compared to total variations. Utilizing copy-number changes of the selected genes, this study suggests a statistical approach to predict patients' classes with increased performance by pre-classifying patients with similar genetic alteration scores. Two-stage logistic regression model(TLRM) was suggested to pre-classify homogeneous patients and predict patients' classes for cancer prediction; a decision tree(DT) was combined with logistic regression on the set of informative genes. TLRM was constructed in cDNA microarray-based CGH data from the Cancer Metastasis Research Center(CMRC) at Yonsei University; it predicted the patients' clinical diagnoses with perfect matches (except for one patient among the high-risk and low-risk classified patients where the performance of predictions is critical due to the high sensitivity and specificity requirements for clinical treatments. Accuracy validated by leave-one-out cross-validation(LOOCV) was 83.3% while other classification methods of CART and DT performed as comparisons showed worse performances than TLRM.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.33-36
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• 2013

클라우드 컴퓨팅 기술은 이용자로 하여금 자원을 편리하게 이용할 수 있게 하며 낮은 TCO(Total Cost of Ownership)를 보장하는 기술로 널리 사용되고 있다. 특히 IaaS에서 많은 기대를 할 수 있는데, 이 기술 중에 하나가 서버 가상화 기술이다. 가상화된 서버를 관리하기 위해서 쓰이는 기술 중 하나가 바로 라이브 가상 머신 마이그레이션으로 이는 서비스를 제공하고 있는 서버의 구동 중지 시간을 줄여 이용자의 불편함을 최소로 하는 기술이다. 그러나 라이브 가상 머신 마이그레이션은 기존의 방법보다 마이그레이션 시간이 길어 네트워크 자원을 오래 쓰는 단점이 있다. 이런 단점을 보완하기 위해 본 논문에서는 pre-copy 예측을 통한 마이그레이션 시간 감축 기법을 제안한다. pre-copy를 예측하는 기법을 소개하고 이를 이용한 통제 알고리즘을 보이며 이를 Xen에 적용했을 때의 결과를 보인다. 적용해본 결과 기존의 방법보다 마이그레이션 시간이 최대 17% 향상됨을 볼 수 있었다.

• Microbiology and Biotechnology Letters
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• v.21 no.3
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• pp.214-220
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• 1993

The mating type a of yeast, Saccharomyces cerevisiae mutant with hmla2-102 and sir3-8ts was changed to type alpha by changing the growth temperature from 25C to 35C. A temperature-sensitive expression vector system was constructed using mating factor alpha1 (Mfalpha1) gene encoding alpha factor which is expressed in the type alpha cells. Vectors with different copy numbers were constructed by joining the promoter and pre or prepro-secretion single sequence of Mfalpha1 to promoterless PHO5' gene as a reporter gene.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.344-358
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• 2022

Text summarization is the task of producing a shorter version of a long document while accurately preserving the main contents of the original text. Abstractive summarization generates novel words and phrases using a language generation method through text transformation and prior-embedded word information. However, newly coined words or out-of-vocabulary words decrease the performance of automatic summarization because they are not pre-trained in the machine learning process. In this study, we demonstrated an improvement in summarization quality through the contextualized embedding of BERT with out-of-vocabulary masking. In addition, explicitly providing precise pointing and an optional copy instruction along with BERT embedding, we achieved an increased accuracy than the baseline model. The recall-based word-generation metric ROUGE-1 score was 55.11 and the word-order-based ROUGE-L score was 39.65.

• Clean Technology
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• v.17 no.2
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• pp.117-123
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• 2011

In this study, evaluation tests for cleaning performance of various cleaning agents and selection of optimal ultrasonic cleaning parameters were executed to develop an efficient cleaning process in remanufacturing of laser copy machine. Cleaning performance tests were executed with 8 cleaning agents (A~H) to remove the contaminants of oil-ink, toner particles, and shoe polish. Physical properties and foamability tests were also applied. For 3 types of contaminants, cleaning agent G showed superior cleaning performance compared to agent A which has being used at a remanufacturing of laser copy machine in Korea. With cleaning agents selected in pre-tests, ultrasonic cleaning tests were executed to remove real contaminants on the parts of used digital laser copy machine parts. Cleaning agent G at 28 kHz ultrasonic frequency showed faster cleaning performance compared to agent A and other frequencies. The productivity and economic efficiency in remanufacturing of laser copy machine are expected to increase by adapting agent G and 28 kHz frequency at ultrasonic cleaning process.

• Journal of Korean Medical classics
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• v.29 no.4
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• pp.37-52
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• 2016

Objectives : The paper seeks to delve into a study of smallpox, specifically as one of the most representative contagious diseases during the Chosun era and how it was treated during that time. The lack of traditional medical texts that deal with smallpox has led this paper to dive into Duchanggyeongheombang. Methods : Everything related to edition and copy, and the author was organized based on pre-existing studies. The copy that is assumed as the original copy was considered and studied. The book was compared to and reviewed with Donguibogam, and the differences between the book and Korean translation were given attention as well. Results : Park Jin-hee is assumed to have authored Duchanggyeongheombang, and it is like that was had access to texts published by the state, one of which includes Donguibogam. He utilized the periods with smallpox outbreaks as his frame of study and put together a series of treatment for different symptoms. To this, he attached various medical charts, and added Korean translation for higher usability. In his book, he placed emphasis on spleen and stomach, but when needed, he did not shy away from using cold and coolness herbs. Conclusions : Duchanggyeongheombang was influenced partially by Donguibogam, but the book was given new life through the author Park Jin-hee's edition. Medical charts were added to increase its usability, and Korean translation was provided for wider audience. Its scope of prescription is very wide, and it provided the reasonings behind its medical judgements based on actual clinical studies instead of being tied down to traditions or taboos.