• The KIPS Transactions:PartD
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• v.9D no.4
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• pp.555-560
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• 2002

Subsequence matching, which consists of index searching and post-processing steps, is an operation that finds those subsequences whose changing patterns are similar to that of a given query sequence from a time-series database. This paper discusses optimization of post-processing for subsequence matching. The common problem occurred in post-processing of previous methods is to compare the candidate subsequence with the query sequence for discarding false alarms whenever each candidate subsequence appears during index searching. This makes a sequence containing candidate subsequences to be accessed multiple times from disk, and also have a candidate subsequence to be compared with the query sequence multiple times. These redundancies cause the performance of subsequence matching to degrade seriously. In this paper, we propose a new optimal method for resolving the problem. The proposed method stores ail the candidate subsequences returned by index searching into a binary search tree, and performs post-processing in a batch fashion after finishing the index searching. By this method, we are able to completely eliminate the redundancies mentioned above. For verifying the performance improvement effect of the proposed method, we perform extensive experiments using a real-life stock data set. The results reveal that the proposed method achieves 55 times to 156 times speedup over the previous methods.

• 한국노년학
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• v.30 no.1
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• pp.127-140
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• 2010

This study aims to understand the effects of a Computer - based Cognitive Rehabilitation Therapy(CBCRT) evidence based on mild dementia patients' ability to activities daily living(ADL), cognitive function and measure of occupational performance and to suggest basic data for a cognitive rehabilitation therapy for dementia patients. Method : A CBCRT was applied two times a week for 5 weeks to 14 mild dementia patients who visited Yongin Center for Managing Dementia in Gyeongi-do between February and August 2009. Based on frame of reference for Visual-Perception a CBCRT was applied at home. Moreover, a one group pretest-post test design was, which is a quasi-experiment and research, also applied in order to verify the effects of the rehabilitation therapy on the subjects' ability to ADL, cognitive function and occupational performance skills. Results: A significant effect was confirmed (p<.05) from the CBCRT which Assessment of Motor and Process Skills(AMPS) processing skills and cognitive function and occupational performance skills. Neither was found any significant effect in improving motor skills from AMPS. Conclusion: It seems that a CBCRT based on evidence and has an effect on the improvement of the ability to ADL and cognitive function of mild dementia patients living in a community. The present author hopes that, in the future, more cognitive rehabilitation programs will be developed to improve the functions of mild dementia patients living in a community.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.276-284
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• 2019

Seismic research on bridges, dams and nuclear power plants, which are infrastructure in Korea, has been carried out since early on, but in the case of structures in thermal power plants, research is insufficient. In this study, a total of 192 dynamic analyzes were performed for 16 actual seismic waves and 12 PGAs. As a result, the probability of failure increased as the PGA value increased for each applied seismic wave, but it was different for each seismic wave. As a result, at 0.22G, the ratio of the compressive limit reached to the limit state was 25% and the ratio of the relative displacement reached the limit state was 13%. So, the probability of collapse due to compressive failure Is higher. Therefore, the fragility curve of the chimney which is the subject of this study can be used as a quantitative basis to determine the limit state of the target structure when an earthquake occurs and to be used for the safety design of the thermal power plants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.651-658
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• 2021

Because bolts with anti-loosening coatings are used mainly for joining safety-related components in automobiles, accurate automatic screening of these coatings is essential to detect defects efficiently. The performance of the convolutional neural network (CNN) used in a previous study [Identification of bolt coating defects using CNN and Grad-CAM] increased with increasing number of data for the analysis of image patterns and characteristics. On the other hand, obtaining the necessary amount of data for coated bolts is difficult, making training time-consuming. In this paper, resorting to the same VGG16 model as in a previous study, transfer learning was applied to decrease the training time and achieve the same or better accuracy with fewer data. The classifier was trained, considering the number of training data for this study and its similarity with ImageNet data. In conjunction with the fully connected layer, the highest accuracy was achieved (95%). To enhance the performance further, the last convolution layer and the classifier were fine-tuned, which resulted in a 2% increase in accuracy (97%). This shows that the learning time can be reduced by transfer learning and fine-tuning while maintaining a high screening accuracy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.326-338
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• 2021

Ultra-performance liquid chromatography (UPLC) was used to assess the hordein protein fraction of malting barley. C-hordeins (barley prolamins) were extracted with 70% ethanol (EtOH) and 55% isopropyl alcohol (IPA, 2-propanol), and B-hordeins were extracted with the same alcohols in 1.0% dithiothreitol (DTT). High molecular weight (HMW) prolamins (D-hordeins) were extracted with 50% IPA with 1M Tris-HCl (pH 8.0). The same protein patterns were observed in both the experimental extraction solutions (EtOH and IPA). However, the patterns of hordein, extracted with EtOH and IPA containing 1.0% DTT, differed slightly. C- and B-hordeins extracted from those solutions were analyzed. Twenty-six malting barley varieties developed in Korea were analyzed using UPLC. The varieties were divided into seven groups according to hordein patterns of retention time 16 min to 18 min, and 20 varieties showed unique patterns.

• Korean Journal of Ichthyology
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• v.34 no.2
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• pp.73-85
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• 2022

The cynoglossid fishes are popular for food in the world including Korea, China and Japan, and among them, Paraplagusia japonica lives all over the sea of Korea. In order to establish appropriate management measure, it is essential to clarify population structure of P. japonica from the morphological and molecular perspectives. We collected a total of 132 individuals of P. japonica from six localities in Korea between 2008 and 2021. Canonical discriminant analysis results showed that the West Sea population (Incheon) slightly differed from the South (Tongyeong, Busan) and East Sea populations (Pohang, Donghae, Sokcho). Similar results were also shown in Kruskal-Wallis test of meristic characters. Furthermore, neighbor-joining and maximum-likelihood trees based on 849 base pairs of mitochondrial DNA cytochrome b sequences showed that P. japonica was divided into two lineages (designated as A and B) with a high significance (Φ_st=0.0781, P<0.001). Interestingly, however, the two lineages in the admixture area (South-East Sea) were not different in morphological characters. Our results suggest that P. japonica had undergone differentiated history during the Late Pleistocene, but secondary contact may occur at the admixture area.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.79-88
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• 2022

Cable-supported bridges, as important large infrastructures, require a long-term and systematic maintenance strategy. In particular, various methods have been proposed to secure safety for the bridges, such as installing various types of sensor on members in the bridges, and setting management thresholds. It is evidently necessary to propose a strategic plan to efficiently manage increasing number of cable-supported bridges and data collected from a number of sensors. This study aims to develop an analysis tool that can automatically remove abnormal signals and calculate statistical results for the purpose of efficiently analyzing a wide range of data collected from a long span bridge measurement system. To develop the tool, basic information such as the types and quantity of sensors installed in long span bridges and signal characteristics of the collected data were analyzed. Thereafter, the Humpel filtering method was used to determine the presence or absence of an abnormality in the signal and then filtered. The statistical results with filtered data were shown. Finally, one cable-stayed bridge and one suspension bridge currently in use were chosen as the target bridges to verify the performance of the developed tool. Signal processing and statistical analysis with the tool were performed. The results are similar to the results reported in the existing work.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.520-524
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• 2023

Regalecus russellii, which spends most of its life in the deep sea, occasionally appears in coastal waters. However, the reasons for its appearance remain unclear. In Korea, R. russellii mainly appears along the eastern coastal waters, and most of them are caught in fishing gear, such as gill nets, or are stranded on the shore; nevertheless, the frequency of appearance is extremely low. Even if found, this species is often identified to be morphologically similar to Trachipterus ishikawae, and comprehensive analysis to identify the species through sample collection is limited. Consequently, information on the biological characteristics of R. russellii appearing in the coastal waters of Korea is scarce. Herein, the anatomical characteristics of R. russellii caught in a gill net off the Gangwon-do coast on March 14, 2023, were analyzed, and coastal water temperature was measured using an ocean buoy. Our results showed that the individual was male, its total length was 320 cm, body weight was 27.52 kg, body length was 26.62 cm, gonad weight was 619.45 g, and liver weight was 218.71 g. The stomach was full of euphausiids. The water temperature changed drastically at 15-30 m roughly a week before the R. russellii individual was caught, and the subsurface water temperature was lower than 10 ℃. Our findings provide baseline data to understand the ecological characteristics of R. russellii appearing along the eastern coast of the Korea.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.305-318
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• 2023

The complexity of software products led many manufacturers to stitch open-source software for composing a product. Using open-source help reduce the development cost, but the difference in the different development life cycles makes it difficult to keep the product up-to-date. For this reason, even the patches for known vulnerabilities are not adopted quickly enough, leaving the entire product under threat. Existing studies propose to use binary differentiation techniques to determine if a product is left vulnerable against a particular vulnerability. Despite their effectiveness in finding real-world vulnerabilities, they often fail to locate the evidence of a vulnerability if it is a small function that usually is inlined at compile time. This work presents our tool FunRank which is designed to identify the short functions. Our experiments using synthesized and real-world software products show that FunRank can identify the short, inlined functions that suggest that the program is left vulnerable to a particular vulnerability.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.267-283
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• 2023

The COVID-19 pandemic, which began in December 2019 and continues to this day, has left the public needing information to help them cope with the pandemic. However, COVID-19-related fake news on social media seriously threatens the public's health. In particular, if fake news related to COVID-19 is massively spread with similar content, the time required for verification to determine whether it is genuine or fake will be prolonged, posing a severe threat to our society. In response, academics have been actively researching intelligent models that can quickly detect COVID-19-related fake news. Still, the data used in most of the existing studies are in English, and studies on Korean fake news detection are scarce. In this study, we collect data on COVID-19-related fake news written in Korean that is spread on social media and propose an intelligent fake news detection model using it. The proposed model utilizes the frequency information of parts of speech, one of the linguistic characteristics, to improve the prediction performance of the fake news detection model based on Doc2Vec, a document embedding technique mainly used in prior studies. The empirical analysis shows that the proposed model can more accurately identify Korean COVID-19-related fake news by increasing the recall and F1 score compared to the comparison model.