• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.31-34
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• 2004

회복기법은 비공유 공간 데이터베이스 클러스터에서 고가용성을 위해 매우 중요하게 고려되고 있다. 일반적으로 데이터베이스 클러스터의 회복기법은 노드의 오류가 발생한 경우 로컬 로그와는 별도로 클러스터 로그를 생성하며, 이를 기반으로 해당 노드에서의 회복과정을 수행한다. 그러나, 기존의 기법은 하나의 레코드를 위해 다수의 갱신정보를 유지함으로써 클러스터 로그의 크기가 증가되고, 전송비용이 증가된다. 이는 회복노드에서 하나의 레코드에 대해 여러 번의 불필요한 연산을 실행하여 회복시간이 증가되고, 전체적인 시스템의 부하를 증가시키는 문제를 발생시킨다. 본 논문에서는 비공유 공간 데이터베이스 클러스터에서 최신버전의 클러스터 로그를 이용한 회복기법을 제안한다. 제안기법에서의 최신버전의 클러스터 로그는 레코드의 변경사항과 실제 데이터를 가리키는 포인터 정보로 구성되고, 하나의 갱신정보를 유지함으로써 클러스터 로그의 크기가 감소하며, 전송비용이 감소한다. 회복노드에서는 하나의 레코드에 대해 한번의 갱신연산만 실행하므로 빠른 회복이 가능하며, 시스템의 가용성을 향상시킨다.

• Journal of Korean Critical Care Nursing
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• v.12 no.1
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• pp.1-12
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• 2019

Purpose : It is widely accepted that addressing multiple symptoms together is the preferred approach in assessment and intervention and results in reduced negative patient outcomes. Yet, there are few studies examining symptom clusters and their impacts on quality of life longitudinally in patients after heart valve surgery. Methods: A total of 101 patients were recruited from a tertiary hospital and were administered questionnaires (at 3, 6, and 10 weeks after the surgery) assessing participants' characteristics, cardiac symptoms, and quality of life. Factor analysis was used to identify symptom clusters. Hierarchical multiple linear regression was used to predict quality of life. Results: Participants were predominantly 70-years old or more with a mean age of 64.34. The two symptom clusters at 3 weeks after the surgery with education, gender, and occupation accounted for 76.3% of variance in quality of life. Conclusion: Symptom clusters containing various physical and psychological symptoms in patients after the surgery affected quality of life, and the relationship was significant at 3 weeks after the surgery. Because symptom clusters were identified in all three recovery periods, nurses need to acknowledge these clusters, rather than each symptom separately, and to utilize these in providing care and education and in promoting quality of life in these patients.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.2
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• pp.97-107
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• 2017

Columnar aerosol properties retrieved from solar radiation were investigated at the Yongin (YGN) SKYNET site over seven years from October 2008 to October 2015. Hourly averages were calculated when the data were available, and back trajectories were calculated to examine the effects of regional transport. Data recovery rate was low at 6.6%, primarily because solar radiation was measured only under daytime clear-sky conditions. Mean values of the fine-mode volume fraction (FMVF) as well as its seasonal variation were similar to those of $PM_{2.5}/PM_{10}$ although the coarse-mode fraction of column aerosols tended to be slightly larger. The values of single scattering albedo (SSA) and FMVF were lower in spring due to the effects of mineral dust, and higher in summer due to secondarily-formed inorganic ions. Back trajectories were grouped into five clusters according to the directions of transport paths. Aerosol loading was highest for Cluster 2 from the northwest, but SSA and FMVF were not particularly high or low because aerosols were composed of various materials with different properties. Aerosol loading was lowest for Cluster 5 from the Pacific Ocean passing through the south end of Japan, whose SSA and FMVF were highest as secondarily-formed inorganic ions were mixed.

• Membrane and Water Treatment
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• v.10 no.3
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• pp.207-212
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• 2019

Non-aqueous solvents (NASs) are generally known to be barely miscible, and reactive with polar compounds, such as water. However, water can interact with some NASs, which can be used as a new means for water recovery from saline water. This study explored the fate of water and salt in NAS, when saline water is mixed with NAS. Three amine solvents were selected as NAS. They had the same molecular formula, but were differentiated by their molecular structures, as follows: 1) NAS 'A' having the hydrophilic group ($NH_2$) at the end of the straight carbon chain, 2) NAS 'B' with symmetrical structure and having the hydrophilic group (NH) at the middle of the straight carbon chain, 3) NAS 'C' having the hydrophilic group ($NH_2$) at the end of the straight carbon chain but possessing a hydrophobic ethyl branch in the middle of the structure. In batch experiments, 0.5 M NaCl water was blended with NASs, and then water and salt content in the NAS were individually measured. Water absorption efficiencies by NAS 'B' and 'C' were 3.8 and 10.7%, respectively. However, salt rejection efficiency was 98.9% and 58.2%, respectively. NAS 'A' exhibited a higher water absorption efficiency of 35.6%, despite a worse salt rejection efficiency of 24.7%. Molecular dynamic (MD) simulation showed the different interactions of water and salts with each NAS. NAS 'A' formed lattice structured clusters, with the hydrophilic group located outside, and captured a large numbers of water molecules, together with salt ions, inside the cluster pockets. NAS 'B' formed a planar-shaped cluster, where only some water molecules, but no salt ions, migrated to the NAS cluster. NAS 'C', with an ethyl group branch, formed a cluster shaped similarly to that of 'B'; however, the boundary surface of the cluster looked higher than that of 'C', due to the branch structure in solvent. The MD simulation was helpful for understanding the experimental results for water absorption and salt rejection, by demonstrating the various interactions between water molecules and the salts, with the different NAS types.

• The KIPS Transactions:PartB
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• v.12B no.7 s.103
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• pp.755-760
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• 2005

To transmit a video bit stream over low bandwith, such as mobile, channels, encoding algorithms for high bit rate like H.263+ are used. In transmitting video bit-streams, packet losses cause severe degradation in image quality. This paper proposes a new algorithm for the recovery of missing or erroneous motion vectors when H.263+ bit-stream is transmitted. Considering that the missing or erroneous motion vectors are closely related with those of neighboring blocks, this paper proposes a temporal-spatial error concealment algorithm. The proposed approach is that missing or erroneous Motion Vectors(MVs) are recovered by clustering the movements of neighboring blocks by their homogeneity. MVs of neighboring blocks we clustered according to ALA(Average Linkage Algorithm) clustering and a representative value for each cluster is determined to obtain the candidate MV set. By computing the distortion of the candidates, a MV with the minimum distortion is selected. Experimental results show that the proposed algorithm exhibits better performance in subjective and objective evaluation than existing methods.

• Journal of Animal Science and Technology
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• v.63 no.1
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• pp.125-136
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• 2021

Bovine coronavirus (BCoV) is associated with severe diarrhea, dehydration, and depression, which result in significant economic damages in the dairy and beef cattle industries worldwide. However, differences in the gut microbiota structure and their correlations with differing physiological parameters between BCoV-infected calves with diarrhea and recovered calves are not well understood. In this study, fecal specimens were collected from 10 post-weaned calves, before and after 2 months of fluid therapy, and the samples were used for microbiota analysis. Following recovery, the alpha-diversity profiles (observed operational taxonomic units [OTUs], and Chao1, Shannon, and Simpson indices) changed significantly when compared with those of calves with diarrhea. Beta-diversity analysis exhibited significant differences in gut microbiota compositions between calves with diarrhea and those in the recovered state. The abundances of eight phyla and thirteen genera in feces changed markedly after restoration of BCoV diarrhea. In addition, our correlation study clearly revealed that increased abundances of the genera Caproiciproducens, Pseudoflavonifractor, and Oscillibacter negatively correlated with serum glucose, and phosphorus levels, but positively correlated with serum chloride in calves with diarrhea, whereas increased abundances of the genera Peptostreptococcaceae;Clostridium (Clostridium cluster XI), Intestinibacter, Cellulosilyticum, Ruminococcus, Romboutsia, Paeniclostridium, Clostridiaceae;Clostridium and Turicibacter in recovered calves showed the opposite pattern. These results suggest that structural changes of the gut microbiota after recovery from BCoV infection correlate with changes in physiological parameters. In conclusion, our data provide evidence of gut microbiota-composition changes and their correlations with the physical profiles of post-weaned calves, before and after fluid therapy for BCoV-related diarrhea.

• Communications for Statistical Applications and Methods
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• v.13 no.3
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• pp.719-732
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• 2006

A set of clustering algorithms with proper weight on the formulation of distance which extend to mixed numeric and multiple binary values is presented. A simple matching and Jaccard coefficients are used to measure similarity between objects for multiple binary attributes. Similarities are converted to dissimilarities between i th and j th objects. The performance of clustering algorithms with balancing weight on different similarity measures is demonstrated. Our experiments show that clustering algorithms with application of proper weight give competitive recovery level when a set of data with mixed numeric and multiple binary attributes is clustered.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.773-776
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• 2007

클러스터 시스템에서 결함이 발생하였을 때, 결함 회복 성능은 매우 중요한 설계 요소가 된다. 단일 입출력 공간(SIOS)을 저장 장치로 사용하는 클러스터 시스템에서, 각 노드들의 결함허용정보를 주기적으로 저장하는 roll-back 결함회복 기법을 사용하는 경우, 결함 회복 성능은 SIOS가 제공하는 입출력 병렬성과 깊은 관계가 있다. 본 연구에서는 클러스터 시스템의 SIOS 구성에 참여하는 노드 수에 따른 결함 회복 성능을 HPL 벤치마크를 통하여 여러 환경에서 평가하고, 그 결과를 분석하였다. 성능 평가 수행 결과, 클러스터 시스템은 SIOS 구성에 참여하는 노드의 수가 증가할수록 우수한 결함 회복 성능을 보인다. 따라서 SIOS를 결함허용정보 저장 장치로 사용하는 클러스터 시스템을 설계할 경우, SIOS 구성에 참여하는 노드 수가 클러스터 시스템의 결함 회복 성능을 결정하는 데에 중요한 요소가됨을 알 수 있다.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.151-158
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• 2014

Asphaltenes are generally defined by their solubility when a light alkane, such as n-heptane or n-pentane, is mixed with crude oils or oil sand bitumen. However, this definition is nowadays not enough to understand their behaviors during oil recovery, transport, storage, and even refinery operation. Interestingly, the researches regarding asphaltenes have been vastly presented within last decade. This is because the production of heavy oils is becoming larger and asphaltenes are known to play an important role in the property changes of heavy oils. In this paper, the researches regarding molecular weight, aggregation behavior of asphaltenes are introduced and discussed. It is expected that analytical studies will be appeared continuously in the form of global collaboration in order to describe asphaltene molecules as close as possible based on their origin.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.03a
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• pp.7-10
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• 2004

회복기법은 비공유 공간 데이터베이스 클러스터에서 고가용성을 위해 매우 중요하게 고려되고 있다. 일반적으로 데이터베이스 클러스터의 회복기법은 노드의 오류가 발생한 경우 로컬 로그와는 별도로 클러스터 로그를 생성하며, 이를 기반으로 해당 노드에서의 회복과정을 수행한다. 그러나, 기존의 기법은 하나의 레코드를 위해 다수의 갱신정보를 유지함으로써 클러스터 로그의 크기가 증가되고, 전송비용이 증가된다. 이는 회복노드에서 하나의 레코드에 대해 털러 번의 불필요한 연산을 실행하여 회복시간이 증가되고, 전체적인 시스템의 부하를 증가시키는 문제를 발생시킨다. 본 논문에서는 비공유 공간 데이터베이스 클러스터에서 확장성 해싱 기반의 로그를 이용한 회복기법을 제안한다. 제안기법에서의 클러스터 로그는 레코드 키값을 이용한 확장성 해싱을 기반으로 레코드의 변경사항과 실제 데이터를 가리키는 포인터 정보로 구성된다. 확장성 해싱 기반의 클러스터 로그는 크기와 전송비용이 감소하며, 회복노드는 하나의 레코드에 대해 한번의 갱신연산만 실행하므로 빠른 회복이 가능하다. 따라서 제안 기법은 확장성 해싱 기반의 클러스터 로그를 이용하여 효율적인 회복처리를 수행하며, 시스템의 가용성을 향상시킨다.