• 한국정보과학회논문지:데이타베이스
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• 제33권1호
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• pp.56-68
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• 2006

RFID 시스템의 태그를 추적하기 위해서는 태그의 궤적을 모델링하고 색인으로 구성해야 한다. 궤적은 태그가 판독기의 인식영역으로 들어갈 때와 나갈 때 보고되는 두 개의 시공간 위치를 연결한 선분으로 표현될 수 있다. 만약 태그가 판독기의 인식영역에 들어와 나가지 않는 경우에 태그의 시공간 위치는 인식영역에 들어올 때만 보고된 점으로 표현된다. 따라서 판독기에 머물고 있는 태그는 궤적을 표현할 수가 없으므로 질의 시 이러한 태그를 검색할 수 없다 이러한 문제를 해결하기 위하여 이 논문에서는 태그의 궤적을 시간 매개변수 간격으로 정의하고 새로운 색인인 TPIR-tree(Time Parameterized Interval R-tree)를 제안한다. 또한 효율적인 질의처리를 위한 새로운 삽입 및 분할 알고리즘을 제안하여 노드가 차지하는 영역을 최소화한다. 마지막으로 제안된 색인을 구현하여 다양한 데이타에서 기존 색인과 성능을 비교한다.

• Geomechanics and Engineering
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• 제14권2호
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• pp.151-159
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• 2018

Annually, the global production of construction aggregates reaches over 40 billion tons, making aggregates the largest mining sector by volume and value. Currently, the aggregate industry is shifting from sand to hard rock as a result of legislation limiting the extraction of natural sands and gravels. A major implication of this change in the aggregate industry is the need for understanding rock fragmentation and energy absorption to produce more cost-effective aggregates. In this paper, we focused on incorporating dynamic rock and soil mechanics to understand the effects of loading rate and water saturation on the rock fragmentation and energy absorption of three different sandstones (Red, Berea and Buff) with different pore sizes. Rock core samples were prepared in accordance to the ASTM standards for compressive strength testing. Saturated and dry samples were subsequently prepared and fragmented via fast and dynamic compressive strength tests. The particle size distributions of the resulting fragments were subsequently analyzed using mechanical gradation tests. Our results indicate that the rock fragment size generally decreased with increasing loading rate and water content. In addition, the fragment sizes in the larger pore size sample (Buff sandstone) were relatively smaller those in the smaller pore size sample (Red sandstone). Notably, energy absorption decreased with increased loading rate, water content and rock pore size. These results support the conclusion that rock fragment size is positively correlated with the energy absorption of rocks. In addition, the rock fragment size increases as the energy absorption increases. Thus, our data provide insightful information for improving cost-effective aggregate production methods.

• 한국콘텐츠학회논문지
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• 제21권9호
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• pp.570-579
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• 2021

여성은 남성에 비해 자본조달에 어려움을 경험하고 있으며, 이는 여성창업가의 성공을 저해하는 요인으로 작용할 수 있다. 이에 본 연구는 창업초기 기업의 투자유치성과에 있어 성별 간 차이를 확인하고, 성별 간 초기 투자유치성과에 영향을 미치는 조직 특성과 창업가 특성에 차이가 존재하는지 검증한다. 수도권 소재 기술기반 창업 기업을 대상으로 한 설문조사를 통해 자료가 수집되었으며, 총 287개의 기업이 분석에 활용되었다. 연구결과, 창업초기 기업의 투자유치성과는 성별 간 유의한 차이가 있는 것으로 확인되었다. 또한 분할그룹 회귀 분석 결과, 남성의 경우 기업연령, 기업규모, 초기자기자본금, 엔지니어 전공 등이 창업초기 기업의 투자유치성과에 유의한 영향을 미치는 것으로 확인된 반면, 여성은 모든 기업 및 창업가 특성 관련 세부 변수들의 영향력이 유의하지 않은 것으로 나타났다. 본 연구결과는 성역할 고정 관념과 같은 편견이 실제로 투자 유치활동과 관련된 경제 활동에 영향을 미친다는 것을 간접적으로 시사한다.

• 한국보육학회지
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• 제19권2호
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• pp.165-176
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• 2019

본 연구의 목적은 유아교사의 생활지도 효능감 개념을 규정하고, 실제 유아교육기관에서 생활지도의 구성요인을 밝혀, 유아교사의 생활지도 효능감을 객관적으로 판단할 수 있는 척도를 개발하는 것이다. 이를 위하여 유아교사에게 요구되는 생활지도의 내용을 추출하고 국내, 외 교사효능감 이론 및 척도에 대한 고찰에 근거하여 83개 예비문항을 선정하였고 델파이방법에 의해 61개 문항을 선정하여 유아교사 243명을 대상으로 예비문항에 대한 응답을 구해 탐색적 요인 분석을 한 결과, 4요인 51문항 (문제행동지도 효능감 21문항, 유아이해 효능감 11문항, 가정연계 효능감 12문항, 기본생활습관지도 효능감 9문항)이 최종 문항으로 선정되었다. 최종척도에 대한 타당도와 신뢰도 검증을 위해 SPSS 프로그램을 사용하여 문항양호도 검증, 요인분석, 상관관계, 문항간 내적 합치도와 반분신뢰도를 산출하였다. 분석결과, 본 척도가 유아교사의 생활지도 효능감을 측정하기에 적합한 도구임이 확인되었다.

• 한국식생활문화학회지
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• 제34권3호
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• pp.268-276
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• 2019

This study separated different factors into the Korean Wave and Korean health food according to the interest in Korean culture among the Chinese living in China. We then conducted a two-step cluster analysis with gender, marriage status, academic background, interest in Korean culture, command of the Korean language and the status of having visited Korea as variables. The subjects were split into a Korean wave-preferring group, highly interested in Korean food as health food group and a low interested group according to clusters, and we then investigated for preference differences for 20 Korean food dishes. Between these two groups the statistics indicated a significant influence with a level p<0.001 for Bulgogi, Bibimbap, Kimchi, Galbi-tang, Galbi-gui, Chicken, Samgyepsal, Doenjang-Jjgae, Dak-galbi, Japchae and Gimbap p<0.01 for Samgye-tang and p<0.05 for Naengmyeon, Kimchi-Jjigae, Dak-galbi, Seolleongtang, Haemul-tang, Hanjeongsik and Tteok-bokki. Jeon and Juk did not show any statistically significant difference. Chinese consumers preferred Korean food for Samgyeopsal, Bulgogi and chicken and less preferred gruel, Hanjeongsik and Kimchi-Jjigae. The highly interested in Korean culture group preferred Samgyeopal, Bulgogi and Chicken, and less preferred Juk, Jeon and Hanjeonsik in that order. This study offers information on the Chinese's preference for different Korean food to any food service enterprises that manage Korean restaurants in China or that sell Korean cuisine and also basic data for differentiated marketing to those entering the Chinese market.

• 한국지반환경공학회 논문집
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• 제20권3호
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• pp.15-20
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• 2019

확한 토공량 설계를 위해서는 충분한 량의 지반조사 자료가 필요하나 비용적인 문제로 인하여 제한적인 지반조사가 수행되고 있다. 정확한 토공량 예측을 위해서 지반의 층상정보를 추정하는 것은 중요한 사항이며, 이러한 제한적인 지반조사 데이터로부터 정확한 토공량 예측을 위해서는 지구통계학적(geo-statistical) 분석방법으로 지반 층상정보를 예측할 수 있다. 또한, 기시추된 지반 층상정보를 활용하여 기계학습을 통하여 모델을 학습하여 미시추된 지반 층상정보를 예측할 수도 있는데, 본 논문에서는 인공신경망을 통하여 미시추된 지반 층상정보를 예측하고 기존의 정규 크리깅 기법과 성능을 비교한다. 이를 위하여, 84공의 지반 층상정보를 활용한다. 84공의 지반 층상정보의 데이터셋 중에서 75공을 학습 데이터셋으로 활용하였고, 나머지 9공을 검증 데이터셋으로 활용하였다. 검증 데이터셋의 실측된 지반 층상정보와 정규 크리깅 기법과 인공신경망으로 예측된 지반 층상정보를 비교 분석한다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제21권1호
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• pp.29-39
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• 2021

Background: Impacted mandibular third molar removal is one of the most commonly performed oral surgical procedures. This procedure can lead to several postoperative complications, such as trismus, facial swelling, and pain, which occur as a result of the inflammatory responses to surgery. This study compared the efficiency of preoperative injections of 4 mg versus 8 mg dexamethasone into the pterygomandibular space to reduce postoperative sequelae. Methods: This was a randomized, prospective, split-mouth, controlled study, including 52 mandibular third molar surgeries in 26 patients. Each patient was randomized to either the 4 mg or 8 mg dexamethasone injection group. Dexamethasone was injected into the pterygomandibular space after numbness from local anesthesia. Data were collected for trismus, facial swelling, visual analog scale (VAS) pain score, and the number of analgesics taken during the evaluation period. The level of significance was set at P < 0.05. Results: Statistically significant differences in postoperative facial swelling (P = 0.031, diff = 1.4 mm) and pain (P = 0.012, diff = 0.020) were found between the 8 mg and 4 mg dexamethasone groups. However, there were no significant differences between the groups for trismus and the total number of analgesics consumed (P > 0.05). Conclusion: Compared to the 4 mg preoperative dexamethasone injection, the 8 mg preoperative dexamethasone injection into the pterygomandibular space was more effective in reducing postoperative swelling and pain following the surgical removal of the impacted mandibular third molar. However, the difference in trismus could not be evaluated clinically. Therefore, the recommendation of administering the 4 mg dexamethasone preoperative injection is optimal in the third molar surgical procedure.

• Advances in environmental research
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• 제9권4호
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• pp.275-284
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• 2020

We provide the first study on the occurrence of microplastics in Dal lake, Kashmir, India. Microplastics act as catastrophe that trigger many environmental problems. The key origins of microplastics are larger plastics, which split into smaller plastics after UV light disintegration. There is relatively little work carried out on the existence of microplastics. The present work has been undertaken on the occurrence of microplastics at four pre-selected sites (surface water) in Dal lake, Kashmir. The samples were taken to the laboratory to dissolve organic matter by using H2O2 (6%). To speed up the organic digestion; the treated mixture was heated on a hot plate at 70℃. The mixture was then subjected to density separation. The supernatant obtained was observed under the microscope (10X) and measurements were taken. At site-I, the microplastics ranged from 2-3 mm, site-II 5-6 mm, site-III 3-4 mm, site-IV 4-5 mm in thickness, indicating the presence of microplastics in the lake. The presence of microplastics indicated that the lake has undergone an anthropogenic change over a period of time. Our research highlights the value of enhancing the quality of the drainage system and sewage disposal. This work can be helpful to recognize successful microplastic control management techniques and possible threats associated with the Dal lake. So far, no such data on the presence of microplastics in Kashmir lakes is available.

• Imaging Science in Dentistry
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• 제52권2호
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• pp.219-224
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• 2022

Purpose: This study aimed to evaluate the performance of transfer learning in a deep convolutional neural network for classifying implant fixtures. Materials and Methods: Periapical radiographs of implant fixtures obtained using the Superline (Dentium Co. Ltd., Seoul, Korea), TS III(Osstem Implant Co. Ltd., Seoul, Korea), and Bone Level Implant(Institut Straumann AG, Basel, Switzerland) systems were selected from patients who underwent dental implant treatment. All 355 implant fixtures comprised the total dataset and were annotated with the name of the system. The total dataset was split into a training dataset and a test dataset at a ratio of 8 to 2, respectively. YOLOv3 (You Only Look Once version 3, available at https://pjreddie.com/darknet/yolo/), a deep convolutional neural network that has been pretrained with a large image dataset of objects, was used to train the model to classify fixtures in periapical images, in a process called transfer learning. This network was trained with the training dataset for 100, 200, and 300 epochs. Using the test dataset, the performance of the network was evaluated in terms of sensitivity, specificity, and accuracy. Results: When YOLOv3 was trained for 200 epochs, the sensitivity, specificity, accuracy, and confidence score were the highest for all systems, with overall results of 94.4%, 97.9%, 96.7%, and 0.75, respectively. The network showed the best performance in classifying Bone Level Implant fixtures, with 100.0% sensitivity, specificity, and accuracy. Conclusion: Through transfer learning, high performance could be achieved with YOLOv3, even using a small amount of data.

• 한국초지조사료학회지
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• 제42권2호
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• pp.103-107
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• 2022

This study was carried out to evaluate the seeding date and performance of early maturing rye cultivars for the Dry matter yield (DMY) and nutritive value during 2016 and 2017 in Yeongseo region of Gangwondo, South Korea. The experimental field was designed as a split-plot arrangement. The treatments were two planting dates on September 25 and October 02 as the main plots, and two cultivars of forage rye including Gogu and Koolgrazer as sub-plots. The cultivars were harvested on April 26 at the heading stage of both years. In this experiment, the sowing dates and cultivars of the forage rye did not effect on DMY. The DMY had no significant differences among the cultivars of forage rye and seeding date of both years. Similarly, no significant difference was observed in the DMY of Gogu and Koolgrazer in both seeding date and years. The CP, NDF, ADF, and RFV had no significant differences among the cultivars of forage rye and seeding date of both years. Considering the DMY and nutritive value of the current experiment, seeding of forage rye cultivars Gogu and Koolgrazer on September 25 and October 2 could be used as an recommended seeding date at northern area. In addition, based on the climate characteristics of the region, both cultivars had relatively similar forage yield and quality that makes them to be recommended for cultivation in the region. This study is meaningful in that DMY was first presented in Yeongseo region where there is no cultivation data for forage rye.