• 화약ㆍ발파
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• 제19권1호
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• pp.71-84
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• 2001

Korean peninsula has the most mountainous areas such as mountains and hilly country, and it is surrounded by the sea on all sides but one. In this respect, a large scaled construction works have frequently been conducted. However, it is not easy to porform a large scale blasting work without giving any harm to houses or facilities nationwide. Therefore, blasting work becomes more closely related to maintenance thing due to the development of the downtown or a large structure for key facilities. Many researches on blast in the open space and tunnel blasting have been conducted. On the contrary, research on underwater blasting operations is comparatively scanty even though much more necessity of marine development is required. In this respect, this study aims to investigate the characteristics of underwater blasting operations and to make a comparative study with blast in the open space. As a result of examining into the characteristics during underwater blasting operations, the around oscillation in case of underwater blasting operations shows significantly low compared to that in case of blast in the open space, and this means that much more cautious altitude must be taken in designing underwater blasting operations compared to the design of blast In the open space. As a result of analysis on the difference between a square root and a cube root In the equation of estimating oscillations in the actual site, it is shown that it is shown to apply a square root for the estimation of oscillation at 60 meters in case of underwater blasting operations and at 22 meters case of general blast in the open space.

• Imaging Science in Dentistry
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• 제52권2호
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• pp.197-207
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• 2022

Purpose: This study evaluated the associations of the dental arch form, age-sex groups, and sagittal root position (SRP) with alveolar bone thickness of the maxillary central incisors using cone-beam computed tomography (CBCT) images. Materials and Methods: CBCT images of 280 patients were categorized based on the dental arch form and age-sex groups. From these patients, 560 sagittal CBCT images of the maxillary central incisors were examined to measure the labial and palatal bone thickness at the apex level and the palatal bone at the mid-root level, according to the SRP classification. The chi-square test, Kruskal-Wallis test, and multiple linear regression were used for statistical analyses. Results: Significant differences were found in alveolar bone thickness depending on the arch form and SRP at the apex level. The square dental arch form and class I SRP showed the highest bone thickness at both levels of the palatal aspect. The taper dental arch form and class II SRP presented the highest bone thickness at the apex level of the labial aspect. No association was found between the dental arch form and SRP. Elderly women showed a significant association with thinner alveolar bone. Age-sex group, the dental arch form, and SRP had significant associations with alveolar bone thickness at the apex level. Conclusion: The patient's age-sex group, dental arch form, and SRP were associated with alveolar bone thickness around the maxillary central incisors with varying magnitudes. Therefore, clinicians should take these factors into account when planning immediate implant placement.

• Asian-Australasian Journal of Animal Sciences
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• 제30권4호
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• pp.546-553
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• 2017

Objective: An experiment was conducted to determine digestible energy (DE) and metabolizable energy (ME) of different byproduct feed ingredients fed to growing pigs, and to generate prediction equations for the DE and ME in feed ingredients. Methods: Twelve barrows with an initial mean body weight of 31.8 kg were individually housed in metabolism crates that were equipped with a feeder and a nipple drinker. A $12{\times}10$ incomplete Latin square design was employed with 12 dietary treatments, 10 periods, and 12 animals. A basal diet was prepared to mainly contain the corn and soybean meal (SBM). Eleven additional diets were formulated to contain 30% of each test ingredient. All diets contained the same proportion of corn:SBM ratio at 4.14:1. The difference procedure was used to calculate the DE and ME in experimental ingredients. The in vitro dry matter disappearance for each test ingredient was determined. Results: The DE and ME values in the SBM sources were greater (p<0.05) than those in other ingredients except high-protein distillers dried grains. However, DE and ME values in tapioca distillers dried grains (TDDG) were the lowest (p<0.05). The most suitable regression equations for the DE and ME concentrations (kcal/kg on the dry matter [DM] basis) in the test ingredients were: $DE=5,528-(156{\times}ash)-(32.4{\times}neutral\;detergent\;fiber\;[NDF])$ with root mean square error = 232, $R^2=0.958$, and p<0.001; $ME=5,243-(153 ash)-(30.7{\times}NDF)$ with root mean square error = 277, $R^2=0.936$, and p<0.001. All independent variables are in % on the DM basis. Conclusion: The energy concentrations were greater in the SBM sources and were the least in the TDDG. The ash and NDF concentrations can be used to estimate the energy concentrations in the byproducts from oil-extraction and distillation processes.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1405-1410
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• 2016

Background: The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Bone Metastases Module (EORTC QLQ-BM22) is a recently designed supplement to EORTC Quality of Life Questionnaire-C30 (EORTC QLQ-C30). Additional psychometric properties, especially using confirmatory factor analysis (CFA) and the Rasch model, are warranted. Materials and Methods: A total of 573 patients with bone metastases were enrolled from eight countries with a mean${\pm}$SD age of $55.8{\pm}13.7years$. Slightly more than two thirds of them were female (n=383; 66.8%). CFA was used to examine the BM22 framework; Rasch models were applied to understand misfit items and differential item functioning (DIF). Results: The fit indices were satisfactory in CFA (comparative fit index=0.972, Tucker-Lewis index=0.964, root mean square error of approximation=0.076, and standardized root mean square residual=0.045). All items fit well in the Rasch models (mean square values were between 0.5 and 1.5), and only one item (number 17) displayed DIF across gender. However, there were six DIF items across Canada and Taiwan, ten across Canada and Iran, and six across Taiwan and Iran. Conclusions: The BM22 has satisfactory psychometric properties, and could assess the QoL of patients with bone metastases specifically focusing on their symptoms. Clinicians may want to use it to capture the underlying QoL for patients with bone metastases. However, the score of item 17 should be interpreted with caution when comparing male and female patients. In addition, researchers should note that variation in DIF items may occur when conducting an international study.

• 한국전자통신학회논문지
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• 제16권1호
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• pp.125-134
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• 2021

영화 산업의 빠른 발전으로 영화의 제작 수가 급격하게 증가하고 있으며, 영화 추천 시스템은 관객들의 과거 행동이나 영화 후기에 기반하여 관객들의 선호도를 예측하여 영화의 선택에 도움을 주고 있다. 본 논문은 평점의 평균과 편향의 보정을 이용하여 잠재요인 모델에 기반한 영화 추천 시스템을 제안한다. 특이값 분해 방법이 평점 매트릭스 분해에 사용되고, 통계 경사 하강법이 최소자승 손실 함수의 파라미터 최적합에 사용된다. 그리고 평균 제곱근 오차를 사용하여 제안한 시스템 성능을 평가한다. Surprise 패키지를 이용하여 제안한 시스템을 구현 하였으며, 모의실험 결과는 평균 제곱근 오차가 0.671이며, 다른 논문에서 방법에 비하여 좋은 성능을 가진다는 것을 확인하였다.

• 대한치과의사협회지
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• 제56권5호
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• pp.254-262
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• 2018

Objectives: This study aimed to compare the postoperative pain and clinical performance after applying three different intracanal medicaments and root canal sealers. Materials and Methods: Sixty-five patients requiring root canal treatment due to symptomatic apical periodontitis were included in this study. After a glide path preparation by using PathFile, each canal was shaped with ProTaper Next file system. After the canal cleaning and shaping procedure, the canal was dried and each intracanal medicaments were adjusted (Calcipex II, TRC-paste, Metapaste). At the next visit, the patients were requested to answer the absence of the pain after the procedure. Once the patients showed no symptom, the canal was obturated with each corresponded root canal sealers (AH plus, Radic-sealer, ADseal). The patients were recalled after 1 week, 1, 3, and 6 months to check the postoperative pain or unexpected clinical signs. One-way ANOVA and Duncan's post hoc comparison, and Chi-square test were used for statistical analysis to evaluate any differences among tested materials. Results: The average number of visits for intracanal medication was 2.69, 2.65, and 2.61 for Calcipex II, TRC-paste, and Metapaste. There were no statistically differences in post-obturation pain among three groups obturated with different root canal sealers (P > 0.05). Conclusions: Under the limitations of this study, three tested intracanal medicaments and epoxy resin root canal sealers showed clinically acceptable similar results.

• 한국환경농학회지
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• 제39권3호
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• pp.204-213
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• 2020

BACKGROUND: Since the number of crops cultivated in reclaimed land is huge, it is very difficult to quantify the total crop production. Therefore, a non-destructive method for predicting crop production is needed. Salt tolerant root vegetables such as red beets and sugar beet are suitable for cultivation in reclaimed land. If their underground biomass can be predicted, it helps to estimate crop productivity. Objectives of this study are to investigate maximum leaf length and weight of red beet, sugar beet, and turnips grown in reclaimed land, and to determine optimal model with regression analysis for linear and allometric growth models. METHODS AND RESULTS: Maximum leaf length, width, and root fresh weight of red beets, sugar beets, and turnips were measured. Ten linear models and six allometric growth models were selected for estimation of root fresh weight and non-linear regression analysis was conducted. The allometric growth model, which have a variable multiplied by square of maximum leaf length and maximum leaf width, showed highest R² values of 0.67, 0.70, and 0.49 for red beets, sugar beets, and turnips, respectively. Validation results of the models for red beets and sugar beets showed the R² values of 0.63 and 0.65, respectively. However, the model for turnips showed the R² value of 0.48. The allometric growth model was suitable for estimating the root fresh weight of red beets and sugar beets, but the accuracy for turnips was relatively low. CONCLUSION: The regression models established in this study may be useful to estimate the total production of root vegetables cultivated in reclaimed land, and it will be used as a non-destructive method for prediction of crop information.

• 대한원격탐사학회지
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• 제33권5_1호
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• pp.559-570
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• 2017

본 연구에서는 야외에서 자료 취득이 가능하며 한 번에 다량의 사과를 촬영할 수 있는 지상용 초분광 스캐너를 활용하여 사과의 분광정보와 당도와의 부분최소제곱회귀분석(PLSR, Partial Least Square Regression)을 수행하였으며, 최적의 예측모델을 구축하기 위한 다양한 전처리기법의 적용가능성을 평가하고 VIP(Variable Importance in Projection)점수를 통한 최적밴드를 산출하였다. 이를 위하여 360-1019 nm영역에서 촬영된 515밴드의 초분광 영상에서 70개의 분광곡선을 취득하였으며, 디지털광도계를 이용하여 당도($^{\circ}Brix$)를 측정하였다. 사과의 분광특성과 당도사이의 회귀모델을 구축하였으며, 최적의 예측모델은 모델 예측치와 실측치간의 결정계수($r_p^2$, coefficient of determination of prediction)와 RMSECV(Root Mean Square Error of Cross Validation), RMSEP(Root Mean Square Error of Prediction)등을 고려하여 선정하였다. 그 결과 산란보정 기법의 대표적인 MSC(Multiplicative Scatter Correction)의 기반의 전처리기법이 가장 효과적이었으며, MSC와 SNV(Standard Normal Variate)를 조합한 경우 RMSECV와 RMSEP가 각각 0.8551과 0.8561로 가장 낮았고, $r_c^2$와 $r_p^2$은 각각 0.8533과 0.6546으로 가장 높았다, 또한 360-380, 546-690, 760, 915, 931-939, 942, 953, 971, 978, 981, 988, 992-1019 nm 등이 당도 측정을 위한 가장 영향력 있는 파장영역으로 나타났다. 해당 영역의 분광값을 가지고 PLSR을 수행한 결과, 전파장대를 사용할 때보다 RMSEP가 0.6841로 감소하고 $r_p^2$는 0.7795로 증가하는 것을 확인하였다. 본 연구를 통하여 사과의 당도측정에 있어 야외에서 취득한 초분광 영상자료의 활용 가능성을 확인하였으며, 이는 필드자료 및 센서 활용분야의 확장가능성을 보여준다.

• 한국토양비료학회지
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• 제43권2호
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• pp.174-179
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• 2010

본 연구에서는 사탕무의 시비반응을 합리적으로 해석하고 경제성 있는 최적 시비량 및 최대 수확량의 도출을 위한 방법을 검토하기 위하여 간척지 토양에서 수준별 질소비료와 돈분퇴비의 시용에 따른 사탕무의 시비반응을 조사하였다. 시비반응은 Quadratic model, Exponential model, Square root model 및 Linear response & plateau model을 이용하여 통계적으로 분석하였다. 토양 EC가 증가함에 따라 사탕무 지하부 생체중이 지수함수적으로 감소하였다. 질소비료 시비수준별 사탕무 지하부 생체량의 시비반응은 Linear response에서 결정계수 & plateau model ($R^2$)가 $0.92^{**}$로 고도의 통계적 유의성을 보였으며, Linear response & plateau model에서 최적 질소시비량 ($N_{opt}$)은 138 kg $ha^{-1}$으로 나타났다. 돈분퇴비의 시비반응은 Quadratic model에서 $0.99^{**}$의 유의성 있는 결정계수 ($R^2$)를 보였으며, 최적 퇴비시비량은 각각 9.17 tons $ha^{-1}$으로 나타났다. 상기 결과로 볼 때 사탕무에서 질소와 돈분퇴비의 시비반응을 적절히 평가하기 위해서는 각각 Linear response & plateau model과 Quadratic model을 이용하는 것이 합리적인 것으로 판단되었다.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.266-275
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• 1996

The purpose of this study was to evaluate the effect of anatomical predisposing factors on the development of furcation involvement. Root trunk length, root divergency angle, buccal root trunk concavity and cervical enamel projection of the mandibular 1st and 2nd molars with(l03 teeth) and without(42 teeth) furcation involvement and enamel projection were classified by Lindhe's degree and Masters's classification, respectively, and buccal root trunk concavity was examined by probing. Statistical analysis was performed by means of ANOVA and CHI-SQUARE test in Microstat. The obtained results were as follows : 1. Root trunk length was longer in teeth without furcation involvement($4.20{\pm}1.05mm$) than teeth with furcation involvement(I : $3.62{\pm}0.68mm$, II : $3.64{\pm}0.86mm$, III: $3.61{\pm}0.74mm$)(p<0.05), but there was fno significant difference among furcation involvement group according to the degree of furcation involvement(p0>.05). 2. The root divergency angle was wider in teeth with furcation involvement(I : $53.14^0{\pm}15.11^0$, II : $44.82^0{\pm}14.26^0$, III : $52.69^0{\pm}16.09^0$) than teeth without furcation involvement($34.81^0{\pm}16.57^0$(p<0.05). 3. The group of teeth without furcation involvement showed significantly hign percentage of teeth without buccal root concavity, and the group of teeth with furcation involvement showed significantly hign percentage of teeth with buccal root concavity(p<0.05) 4. The group of teeth without furcation involvement showed higher percentage of teeth with grade I cervical enamel projection, teeth with furcation involvement I or II defect showed higher percentage of teeth with grade II enamel projection, and teeth with furcation involvement III defect showed higher percentage of teeth with grade III enamel projection(p<0.05) The results suggest that short root trunk length, wide root divergency, buccal root concavity and well-developed enamel projection could affect development and progression of furcation involvement as anatomical predisposing factors of periodontal diseases.