• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.1-6
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• 2002

How is the flow in a rotating impeller. About 35 years have passed since one experimentalist rotating with the impeller. of a huge centrifugal blower made the flow measurements using a hot-wire anemometer (Fowler 1968). Optical measurement methods have great advantages over the intrusive methods especially for the flow measurement in a rotating impeller. One is the optical flow visualization (FV) technique (Senoo, et al., 1968) and the other is the application of laser velocimetry (LV) (Hah and Krain, 1990). Particle image velocimetries (PIVs) combine major features of both FV and LV, and are very attractive due to the feasibility of simultaneous and multi-points measurements (Hayami and Aramaki, 1999). A high-pressure-ratio transonic centrifugal compressor with a low-solidity cascade diffuser was tested in a closed loop with HFC134a gas at 18,000rpm (Hayami, 2000). Two kinds of measurement techniques by image processing were applied to visualize a flow in the compressor. One is a velocity field measurement at the inducer of the impeller using a PIV and the other is a pressure field measurement on the side wall of the cascade diffuser using a pressure sensitive paint (PSP) measurement technique. The PIV was successfully applied for visualization of an unsteady behavior of a shock wave based on the instantaneous velocity field measurement (Hayami, et al., 2002b) as well as a phase-averaged velocity vector field with a shock wave over one blade pitch (Hayami, et al., 2002a. b). A violent change in pressure was successfully visualized using a PSP measurement during a surge condition even though there are still some problems to be overcome (Hayami, et al., 2002c). Both PIV and PSP results are discussed in comparison with those of laser-2-focus (L2F) velocimetry and those of semiconductor pressure sensors. Experimental fluid dynamics (EFDs) are still growing up more and more both in hardware and in software. On the other hand, computational fluid dynamics (CFDs) are very attractive to understand the details of flow. A secondary flow on the side wall of the cascade diffuser was visualized based either steady or unsteady CFD calculations (Bonaiuti, et al.,2002). EFD and CFD methods will be combined to a hybrid method being complementary to each other. Measurement techniques by image processing as well as CFD calculations give a huge amount of data. Then, data mining technique will become more important to understand the flow mechanism both for EFD and CFD.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.584-590
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• 2017

Objective : Traumatic brain injury (TBI) in children under age 24 months has characteristic features because the brain at this age is rapidly growing and sutures are opened. Moreover, children this age are completely dependent on their parents. We analyzed the demographic data and risk factors for outcomes in TBI patients in this age group to elucidate their clinical characteristics. Methods : We retrospectively reviewed the medical records and radiological films of children under 24 months who were admitted to Kyungpook National University Hospital from January 2004 to December 2013 for TBI. Specifically, we analyzed age, cause of injury, initial Glasgow coma scale (GCS) score, radiological diagnosis, seizure, hydrocephalus, subdural hygroma, and Glasgow outcome scale (GOS) score, and we divided outcomes into good (GOS 4-5) or poor (GOS 1-3). We identified the risk factors for post-traumatic seizure (PTS) and outcomes using univariate and multivariate analyses. Results : The total number of patients was 60, 39 males and 21 females. Most common age group was between 0 to 5 months, and the median age was 6 months. Falls were the most common cause of injury (n=29, 48.3%); among them, 15 were falls from household furniture such as beds and chairs. Ten patients (16.7%) developed PTS, nine in one week; thirty-seven patients (61.7%) had skull fractures. Forty-eight patients had initial GCS scores of 13-15, 8 had scores of 12-8, and 4 had scored 3-7. The diagnoses were as follows : 26 acute subdural hematomas, 8 acute epidural hematomas, 7 focal contusional hemorrhages, 13 subdural hygromas, and 4 traumatic intracerebral hematomas larger than 2 cm in diameter. Among them, two patients underwent craniotomy for hematoma removal. Four patients were victims of child abuse, and all of them had PTS. Fifty-five patients improved to good-to-moderate disability. Child abuse, acute subdural hematoma, and subdural hygroma were risk factors for PTS in univariate analyses. Multivariate analysis found that the salient risk factor for a poor outcome was initial GCS on admission. Conclusion : The most common cause of traumatic head injury in individuals aged less than 24 months was falls, especially from household furniture. Child abuse, moderate to severe TBI, acute subdural hematoma, and subdural hygroma were risk factors for PTS. Most of the patients recovered with good outcomes, and the risk factor for a poor outcome was initial mental status.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.187-193
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• 2019

Key-value storage engines are an essential component of growing demand in many computing environments, including social networks, online e-commerce, and cloud services. Recent key-value storage engines offer many features such as transaction, versioning, and replication. In a key-value storage engine, transaction processing provides atomicity through Write-Ahead-Logging (WAL), and a synchronous commit method for transaction processing flushes log data before the transaction completes. According to our observation, flushing log data to persistent storage is a performance bottleneck for key-value storage engines due to the significant overhead of fsync() calls despite the various optimizations of existing systems. In this article, we propose a group synchronization method to improve the performance of the key-value storage engine. We also design and implement a transaction scheduling method to perform other transactions while the system processes fsync() calls. The proposed method is an efficient way to reduce the number of frequent fsync() calls in the synchronous commit while supporting the same level of transaction provided by the existing system. We implement our scheme on the WiredTiger storage engine and our experimental results show that the proposed system improves the performance of key-value workloads over existing systems.

• Korean Journal of Food Science and Technology
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• v.51 no.2
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• pp.141-146
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• 2019

Sparassis crispa is an edible mushroom that is distributed in Korea, Japan, Europe, and North America. It exerts various biological activities such as immunopotentiation, anti-diabetic, anti-cancer, and anti-inflammatory effects. Recently, we separated the health functional non-aqueous fraction from the chloroform extract of S. crispa (SCF4). In this study, we evaluated the antiangiogenic activity of SCF4 in human umbilical vein endothelial cells (HUVECs). SCF4 effectively inhibited vascular endothelial growth factor (VEGF)-induced cell growth at concentrations ($5-25{\mu}g/mL$) showing no cytotoxic effects. SCF4 inhibited VEGF-induced invasiveness and tube formation ability, which are in vitro angiogenic features of HUVECs, in a dose-dependent manner. In addition, SCF4 markedly suppressed in vivo angiogenesis of chorioallantoic membrane from growing chick embryos without cytotoxicity. Furthermore, SCF4 downregulated the phosphorylation of VEGFR2, AKT, and ERK1/2, which are major angiogenic signal mediators. These results suggest that SCF4 inhibited angiogenesis by suppressing the VEGFR2 signaling pathways without cytotoxicity.

• Journal of the Korean Society of Radiology
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• v.79 no.5
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• pp.259-263
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• 2018

A 52-year-old male complained of a painless, firm, and slow-growing mass in his right breast outer portion. The chest CT revealed a 3.3 cm-sized oval shaped, microlobulated, mild enhancing mass. Ultrasound showed a microlobulated marginated heterogeneous hypoechoic mass with internal vascularity and calcifications in the mass. On the ultrasound-guided core needle biopsy, the mass was confirmed as a benign granular cell tumor (GCT). The patient transferred to another hospital and underwent surgical removal of the lesion. GCT of the breast is uncommon and mostly benign neoplasm to originate from Schwann cell. Clinical and radiologic features of GCTs, including CT and ultrasound images, mimic malignancy and make diagnosis of GCT more difficult. The CT images of GCTs are much rarely reported. Physicians and radiologists must be aware of radiologic characteristics of this rare benign tumor for male breast, to avoid misdiagnosis this tumor for breast malignancy and overtreat.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.565-576
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• 2011

This study was conducted to describe forest stand characteristics of the habitats of Allium victorialis var. platyphyllum population from the ecological analysis of classification of vegetation types, importance values, species diversity, interspecific association and community similarity in Ulleung Island and Mt. Hambaek, in which investigated by 48 plots ($10m{\times}10m$). The vegetation studied was classified into 1 community group, 2 communities, 2 groups and 3 subgroups for a species unit and divided by 5 units for a vegetation unit. In the Fagus engleriana group (vegetation unit 1, 2 and 3), importance value of A. victorialis var. platyphyllum in herb layer showed relatively higher value than other units. Importance value of A. victorialis var. platyphyllum in herb layer had higher value. In the analysis of interspecific association, most of the species associated positively to A. victorialis var. platyphyllum belonged to habitat features of valley area and sub-alpine zone. Therefore, it was considered that the growing environment of A. victorialis var. platyphyllum population was closely correlated to soil moisture and air humidity.

• Journal of the Daesoon Academy of Sciences
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• v.34
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• pp.107-139
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• 2020

This paper primarily focuses on the highest deity, the Upper Thearch of the Nine Heavens (officially translated as 'The Supreme God of the Ninth Heaven'), in the Korean new religious movement (NRM) Daesoon Jinrihoe and the true minister of the myriad spirits in the Taiwanese NRM, Yiguan Dao, the Upper Thearch of Manifest Luminosity. As the two both serve as highly representative "Upper Thearch" beliefs in emerging NRMs, I attempt a comparative analysis of the source of these beliefs, their characteristics, and the links that exist between them. On the basis of ancient Chinese classics and Daoist texts, along with Daesoon Jinrihoe's scriptures and works from Yiguan Dao's Canon, I try to understand the distinguishing features of cosmological ideas from both religious movements. For example, because the Upper Thearch of the Nine Heavens could not bear to see the human realm growing ever more disordered and in order to improve worldly conditions, he traveled to the harmonized realm of deities, and therefore descended into the world to make a great itineration and enlighten the people through his teachings. In the end, he came to Korea and was reborn as Kang Jeungsan (secular name: Kang Il-Sun) in Gaekmang Village. In the Human Realm, he spread his transformative teachings to the people which were later became the doctrines of the Virtuous Concordance of Yin and Yang, Harmonious Union between Divine Beings and Human Beings, the Resolution of Grievances for Mutual Beneficence, and Perfected Unification (jingyeong 真境) with the Dao. Yiguan Dao; however, explains that the source of humanity is the "Heaven of Principle" (Litian 理天), and people are "Buddha's Children of the Original Embryo" (Yuantai Fozi 原胎佛子), created by the Upper Thearch of Manifest Luminosity, who came to world to govern and impart spiritual refinement, before returning to his native place in the Heaven of Principle. Yet, because he became infatuated with the world of mortals, he forgot the path of his return. Therefore, the Eternal Mother sent Maitreya Buddha, the Living Buddha Jigong 濟公, and the Bodhisattva of Moon Wisdom (Yuehui pusa 月慧菩薩) to descend to the human world and teach the people, so that they may acknowledge the Eternal Mother as the root of return, achieve their return to the origin, and go back to the home of the Eternal Mother in the Heaven of Principle. Both Daesoon Jinrihoe and Yiguan Dao refer to their highest deity, the true ministers of the myriad spirits, with the simple title "Upper Thearch." This phenomenon also has some ties to God in the western Biblical tradition but also has some key differences. In investigating the sources of these two deities, we find that they likely took shape during the Yinshang (殷商) period and have some relationship to the Upper Thearch of Chinese antiquity. The questions raised in this research are quite interesting and deserving of deeper comparative study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.830-860
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• 2022

[Introduction] Nowadays, many companies are shifting their businesses online due to the growing trend among customers to buy and shop online, as people prefer online purchasing products. [Problem] Users share a vast amount of information about products, making it difficult and challenging for the end-users to make certain decisions. [Motivation] Therefore, we need a mechanism to automatically analyze end-user opinions, thoughts, or feelings in the social media platform about the products that might be useful for the customers to make or change their decisions about buying or purchasing specific products. [Proposed Solution] For this purpose, we proposed an automated SentiDecpective approach, which classifies end-user reviews into negative, positive, and neutral sentiments and identifies deceptive crowd-users rating information in the social media platform to help the user in decision-making. [Methodology] For this purpose, we first collected 11781 end-users comments from the Amazon store and Flipkart web application covering distant products, such as watches, mobile, shoes, clothes, and perfumes. Next, we develop a coding guideline used as a base for the comments annotation process. We then applied the content analysis approach and existing VADER library to annotate the end-user comments in the data set with the identified codes, which results in a labelled data set used as an input to the machine learning classifiers. Finally, we applied the sentiment analysis approach to identify the end-users opinions and overcome the deceptive rating information in the social media platforms by first preprocessing the input data to remove the irrelevant (stop words, special characters, etc.) data from the dataset, employing two standard resampling approaches to balance the data set, i-e, oversampling, and under-sampling, extract different features (TF-IDF and BOW) from the textual data in the data set and then train & test the machine learning algorithms by applying a standard cross-validation approach (KFold and Shuffle Split). [Results/Outcomes] Furthermore, to support our research study, we developed an automated tool that automatically analyzes each customer feedback and displays the collective sentiments of customers about a specific product with the help of a graph, which helps customers to make certain decisions. In a nutshell, our proposed sentiments approach produces good results when identifying the customer sentiments from the online user feedbacks, i-e, obtained an average 94.01% precision, 93.69% recall, and 93.81% F-measure value for classifying positive sentiments.

• Journal of Korea Entertainment Industry Association
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• v.15 no.2
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• pp.21-34
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• 2021

One of the important issues in finance literature is how the capital structure influences firm performance. This paper aims to investigate this relationship by focusing specifically on the entertainment industry. Taking into account the growing importance of research and development (R&D) activities in the industrial revolution 4.0 era, an additional goal of this paper is to examine how the R&D intensity moderates the relationship between the capital structure and firm performance, particularly in the entertainment industry. We find that the relationship between the capital structure measured by debt ratio and the firm performance in the entertainment industry shows distinctive features from those obtained from entire industries. While the negative influence of the increase of debt ratio is strong and consistent with various proxies when using a sample with entire industries, we cannot find this distinctive influence among entertainment enterprises. The moderating effect of R&D investments on the negative influence of debt ratio on the firm value, observed in the sample with entire industries, is not found in the sample composed of entertainment companies. These findings suggest that the influence of the debt level on firm performance and the role of R&D investments in this relationship in the entertainment industry are perceived and evaluated differently by financial market participants.

• Journal of Intelligence and Information Systems
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• v.28 no.3
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• pp.139-159
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• 2022

As interest in health functional foods has increased since COVID-19, the importance of imported food safety inspections is growing. However, in contrast to the annual increase in imports of health functional foods, the budget and manpower required for inspections for import and export are reaching their limit. Hence, the purpose of this study is to propose a machine learning model that efficiently detects unsuitable food suitable for the characteristics of data possessed by government offices on imported food. First, the components of food import/export inspections data that affect the judgment of nonconformity were examined and derived variables were newly created. Second, in order to select features for the machine learning, class imbalance and nonlinearity were considered when performing exploratory analysis on imported food-related data. Third, we try to compare the performance and interpretability of each model by applying various machine learning techniques. In particular, the ensemble model was the best, and it was confirmed that the derived variables and models proposed in this study can be helpful to the system used in import/export inspections.