• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.2
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• pp.335-343
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• 2014

It is more important to ensure the credibility of internet media which influence the public opinion. However, there are vague suspicions in public from the examples of manipulation of online reviews with anonymity. In this study, we explore the possibility of manipulating public opinion in online web sites. We investigate the characteristics of comments posted by users on web sites and compare each comments by using the cosine similarity function. Our result shows followings. First, we found a correlation between the similarities of comments and the article ranks in the web sites. Second, it is possible to identify abnormal user activities indicating excessive multiple posting, double posting and astroturf activities.

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1217-1233
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• 2018

Following a surge of interest in multi-unit risk in the last few years, many recent studies have suggested methods for multi-unit probabilistic safety assessment (MUPSA) and addressed several related aspects. Most of the existing studies though focused on two-unit nuclear power plant (NPP) sites or used rather simplified probabilistic safety assessment (PSA) models to demonstrate the proposed approaches. When considering an NPP site with three or more units, some approaches are inapplicable or yield very conservative results. Since the number of such sites is increasing, there is a strong need to develop and validate practical approaches to the related MUPSA. This article provides several detailed approaches that are applicable to multi-unit Level 1 PSA for sites with up to six or more reactor units. To validate the approaches, a multi-unit Level 1 PSA model is developed and the site core damage frequency is estimated for each of four representative multi-unit initiators, as well as for the case of a simultaneous occurrence of independent single-unit initiators in multiple units. For this purpose, an NPP site with six identical OPR-1000 units is considered, with full-scale Level 1 PSA models for a specific OPR-1000 plant used as the base single-unit models.

• Journal of Korean Society on Water Environment
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• v.39 no.4
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• pp.269-287
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• 2023

The genus-level biotic index of benthic macroinvertebrates (Benthic Macroinvertebrates Genus Index, BMGI) was developed and applicated based on the data collected from 13,347 sampling units of 814 sites from 2010 to 2021 in Korea. Tolerant values of 274 indicator taxa were established by analyzing the relationship between the relative frequency and abundance of indicator taxa and the water quality index considering biochemical oxygen demand (BOD₅), total suspended solids (TSS), and total phosphorus (T-P). BMGI showed a slightly higher correlation with water quality than the species-level biotic index (Benthic Macroinvertebrates Index, BMI) that was developed and applied in Korea. Although the BMGI does not contain species-level information, the reason why BMGI shows higher applicability than BMI seems to be due to the increase in the number of indicator taxa and the decrease in the misidentification of immature aquatic insects. The coefficient of determination in multiple regression with BOD₅, TSS, and TP for BMGI was 0.62 in the long-term averaged data of 814 sites, and the standardized coefficient of BOD₅ was -0.46, TSS was -0.17 and T-P was -0.21, respectively. As a result of the evaluation by BMGI, of the 814 sites, 38% were in good, 25% in fair, and 37% in poor condition.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.66-70
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• 2016

Introduction: Distant metastases of mucoepidermoid carcinoma (MEC) are reported with the most common sites being the soft tissue of skin, lung, liver, and bone. We report here a very rare case of MEC with multiple metastases to the kidney, adrenal gland, skull and gluteus maximus muscle. Case report: A 63-year-old male patient presented with left-sided headache. Radiologic evaluations including CT and MRI showed ill-defined soft tissue lesion involving the left infratemporal fossa and left sphenoid sinus, and multiple enlarged lymph nodes in neck and mediastinum. PET-CT demonstrated multiple hypermetabolic lesions in and around the left kidney, left adrenal gland, right ischium, right gluteus maximus and skull base. These lesions were confirmed as MEC with multiple metastases through biopsy. Discussion: Only one case of metastasis to the skull has been previously reported, and moreover, there has not been a case of metastatic MEC to the kidney, adrenal gland and gluteus maximus muscle so far in the medical literature. It is important to acknowledge the possibility of every unusual MEC metastases, since the presence of metastasis has statistically significant influence on the survival of MEC.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.271-285
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• 2009

Multi-temporal satellite imagery can be changed into a transform image that emphasizes the changed area only through the application of various change detection techniques. From the transform image, an automated change detection model calculates the optimal threshold value for classifying the changed and unchanged areas. However, the model can cause undesirable results when the histogram of the transform image is unbalanced. This is because the model uses a single threshold value in which the sign is either positive or negative and its value is constant (e.g. -1, 1), regardless of the imbalance between changed pixels. This paper proposes an advanced method that can improve accuracy by applying separate threshold values according to the increased or decreased range of the changed pixels. It applies multiple threshold values based on the cumulative producer's and user's accuracies in the automated binary change detection model, and the analyst can automatically extract more accurate optimal threshold values. Multi-temporal IKONOS satellite imagery for the Daejeon area was used to test the proposed method. A total of 16 transformation results were applied to the two study sites, and optimal threshold values were determined using accuracy assessment curves. The experiment showed that the accuracy of most transform images is improved by applying multiple threshold values. The proposed method is expected to be used in various study fields, such as detection of illegal urban building, detection of the damaged area in a disaster, etc.

• Journal of the Korean Society of School Health
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• v.14 no.2
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• pp.215-225
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• 2001

The purpose of this study was to identify factors related to High School Students' Attitudes(prejudice) toward HIV-infected classmates. 980 self-administrated questions were completed by high school male students. Stepwise Multiple Regression Analysis was performed with the following independent variables: knowledge about HIV/AIDS transmission, prevention, and HIV-antibody, interests, preventive behaviors, predicting level to peer HIV-related risk behavior, knowledge about information sites, perceived susceptibility, perceived severity, self-efficacy to prevention, related to AIDS/HIV, thought about premarital sexual behavior and homosexuality. The Regression Model is significant(R2=.1719, F=33.517, p<0.05) The significant factors are knowledge about HIV/AIDS transmission, intention of the preventive behaviors, knowledge of information sites, perceived severity, ideas about homosexuality, predicting level of peer HIV-related risk behavior. The results of this study provide information for effective education program development and health policy about AIDS prevention and management.

• Structural Engineering and Mechanics
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• v.63 no.4
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• pp.457-469
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• 2017

This manuscript deals with a novel approach aimed at identifying multiple damaged sites in structural components through finite frequency changes. Natural frequencies, meant as a privileged set of modal data, are adopted along with a numerical model of the system. The adoption of finite changes efficiently allows challenging characteristic problems encountered in damage detection techniques such as unexpected comparison of possible shifted modes and the significance of modal data changes very often affected by experimental/environmental noise. The new procedure extends MDLAC and exploits parallel computing on modern multicore processors. Smart filters, aimed at reducing the potential damaged sites, are implemented in order to reduce the computational effort. Several use cases are presented in order to illustrate the potentiality of the new damage detection procedure.

• Journal of Microbiology and Biotechnology
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• v.10 no.2
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• pp.264-266
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• 2000

A new GFP-based T-vector for cloning of PCR products was developed by using a green fluorescent protein (GFP) as a mafker. In order to facilitate the DNA inserts, multiple restriction sites, SP6 and T7 RNA polymerase promoter sites, were introduced close to the PCR DNA insertion site of a pCRGv vector. The XcmI-digested pHNT plasmid can be used to clone a 3' A-overhanged PCR DNA amplified by Taq DNA polymerase. A potential method of easing some difficulties from its use along with its cost savings proveded by this vector are likely to lead to the replacement of other T-vectors for PCR DNA cloning.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.39-47
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• 2007

The relationships between the cover of herbaceous species and 15 soil chemical properties (organic carbon contents, total N, available P, exchangeable K, Na, Ca and Mg, HCl-extractable Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in nine poorly controlled waste landfill sites in Korea were examined by correlation analysis and multiple regression equations. Species showed different patterns of correlation between their cover values and soil chemical properties. The cover of Ambrosia artemisiifolia var. elatior, Aster subulatus var. sandwicensis and Erechtites hieracifolia were negatively correlated with the contents of Fe, Mn and Ni within landfill soils. Total cover of all species in quadrats was positively correlated with the contents of Cd and negatively correlated with the contents of Mn and Fe from stepwise regression analysis with 15 soil properties. Canonical correspondence analysis demonstrated that the distribution of native and exotic plants on poorly controlled landfills was significantly influenced by the contents of Na and Ca in soils, respectively.

• Animal cells and systems
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• v.3 no.4
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• pp.413-415
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• 1999

Our previous report demonstrated that the rhp51$^＋$, a recA and RAD51 homolog of the fission yeast, encodes three transcripts of 1.9, 1.6 and 1.3 kb which have at least six polyadenylation sites. The 3'-end of the gene alone can direct the formation of multiple, discrete 3'ends of the transcripts. To identify the regulatory element required for the 3'-end formation of -rhp51$^＋$ deletion mapping analysis was performed. Northern blot analysis revealed that the 254-bp DNA fragment including 4 distinct poly (A) sites downstream from the Hindlll site, is crucial for normal 3'-end formation. Deletion of the 3'-terminal AU rich region caused appearance of read-through RNA, leading to enhancement of survival rate of the rhp51 deletion mutant in response to DNA damaging agent, methylmethane sulfonate (MMS). The results imply that the rhp51$^＋$ system may be useful for molecular analysis of the 3'-end formation of RNA in the fission yeast.