• 한국조경학회지
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• 제31권3호
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• pp.74-82
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• 2003

Under the assumption that the temperature of one location is closely related to land use characteristics around that location, this study is carried out to assess the impact of urban land use patterns on air temperature. In order to investigate the relationship, GIS techniques and statistical analyses are utilized, after spatially connecting urban land use data in Seoul Metropolitan Area with atmospheric data observed at Automatic Weather Stations (AWS). The research method is as follows: (1) To find out important land use factors on temperature, simple linear regressions for a specific time period (pilot study) are conducted with urban land use characteristics, (2) To make a final model, multiple regressions are carried out with those factors and, (3) To verify that the final model could be appled to explain temperature variations beyond the period, the model is extensively used for 5 different time periods: 1999 as a whole; summer in 1999; 1998 as a whole; summer in 1998; August in 1998. The results of simple linear regression models in the pilot study show that transportation facilities and open space area are very influential on urban air temperature variations, which explain 66 and 61 percent of the variations, respectively. However, the other land use variables (residential, commercial, and mixed land use) are found to have weak or insignificant relationship to the air temperatures. Multiple linear regression with the two important variables in the pilot study is estimated, which shows that the model explains 75 percent of the variability in air temperatures with correct signs of regression coefficients. Thus, it is empirically shown that an increase in open space and a decrease in transportation facilities area can leads to the decrease in air temperature. After the final model is extensively applied to the 5 different time periods, the estimated models explain 68 ∼ 75 percent of the variations in the temperatures is significant regression coefficients for all explanatory variables. This result provides a possibility that one air temperature model for a specific time period could be a good model for other time periods near to the period. The important implications of this result to lessen high air temperature we: (1) to expand and to conserve open space and (2) to control transportation-related factors such as transportation facilities area, road pavement and traffic congestion.

• 한국구조물진단유지관리공학회 논문집
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• 제20권4호
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• pp.1-8
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• 2016

최근의 건축물은 복합적인 기능과 형태를 보이고 있으며, 크기가 거대해짐에 따라 구조물 건전성 감시(Structural Health Monitoring)기술의 수요 또한 증가하고 있다. 구조물마다 고유한 동특성을 가지고 있으며, 다양한 외력의 영향을 받기 때문에 구조물의 건전성을 평가하는 다양한 방법들이 연구되고 있다. 전문가에 의지하여 접근 가능한 지점에 대한 육안 검사 및 비파괴 검사를 벗어나 사각지대가 없는 온라인 계측 시스템의 구비와 함께 자동으로 위험요소를 검출하는 시스템이 요구되고 있다. 본 연구에서는 비선형적인 구조물의 응답을 고려하기 위해 관리도 기법, 평균제곱근편차, 일반 극치 분포 등과 같은 통계적 기법을 이용하여 이상거동을 판별에 활용할 수 있는 신호 특징 추출과 적응형 임계치 설정 알고리즘을 제안하였으며, 강제진동 실험과 실제 운용중에 있는 구조물의 지진 계측 시스템의 가속도 응답을 이용하여 성능을 검증하였다.

• International Journal of Computer Science & Network Security
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• 제22권5호
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• pp.294-302
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• 2022

Detection of fake news is a complex and a challenging task. Generation of fake news is very hard to stop, only steps to control its circulation may help in minimizing its impacts. Humans tend to believe in misleading false information. Researcher started with social media sites to categorize in terms of real or fake news. False information misleads any individual or an organization that may cause of big failure and any financial loss. Automatic system for detection of false information circulating on social media is an emerging area of research. It is gaining attention of both industry and academia since US presidential elections 2016. Fake news has negative and severe effects on individuals and organizations elongating its hostile effects on the society. Prediction of fake news in timely manner is important. This research focuses on detection of fake news spreaders. In this context, overall, 6 models are developed during this research, trained and tested with dataset of PAN 2020. Four approaches N-gram based; user statistics-based models are trained with different values of hyper parameters. Extensive grid search with cross validation is applied in each machine learning model. In N-gram based models, out of numerous machine learning models this research focused on better results yielding algorithms, assessed by deep reading of state-of-the-art related work in the field. For better accuracy, author aimed at developing models using Random Forest, Logistic Regression, SVM, and XGBoost. All four machine learning algorithms were trained with cross validated grid search hyper parameters. Advantages of this research over previous work is user statistics-based model and then ensemble learning model. Which were designed in a way to help classifying Twitter users as fake news spreader or not with highest reliability. User statistical model used 17 features, on the basis of which it categorized a Twitter user as malicious. New dataset based on predictions of machine learning models was constructed. And then Three techniques of simple mean, logistic regression and random forest in combination with ensemble model is applied. Logistic regression combined in ensemble model gave best training and testing results, achieving an accuracy of 72%.

• Journal of Welding and Joining
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• 제32권6호
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• pp.8-13
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• 2014

One of the main challenges of the automatic arc welding process which has been widely used in various constructions such as steel structures, bridges, autos, motorcycles, construction machinery, ships, offshore structures, pressure vessels, and pipelines is to create specific welding knowledge and techniques with high quality and productivity of the production-based industry. Commercially available automated arc welding systems use simple control techniques that focus on linear system models with a small subset of the larger set of welding parameters, thereby limiting the number of applications that can be automated. However, the correlations of welding parameters and bead geometry as welding quality have mostly been linked by a trial and error method to adjust the welding parameters. In addition, the systematic correlation between these parameters have not been identified yet. To solve such problems, a new or modified models to determine the welding parameters for tandem GMA (Gas Metal Arc) welding process is required. In this study, A new predictive model called STACO model, has been proposed. Based on the experimental results, STACO model was developed with the help of a standard statistical package program, MINITAB software and MATLAB software. Cross-comparative analysis has been applied to verify the reliability of the developed model.

• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.121-132
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• 1991

The purpose of the study was to evaluate the marginal sealing effect of composite resin inlays according to the luting techniques and compare them to the conventional direct resin filling technique. 90 cavities of class V were prepared on the buccal surface of 90 extracted molar teeth, which were divided into four groups. Cavities of control group were directly filled with Scotchbond 2 and P - 50, and those of composite resin inlay groups were luted with one of the followings: Adhesive bond followed by Adhesive cement, All bond followed by Adhesive cement, Fuji - ionomer type L All the specimens were immersed in India ink dye solution for 7 days at $37^{\circ}C$ incubator after thermocycling between $5^{\circ}C$ and $60^{\circ}C$ and longitudinally sectioned with diamond disk inot two parts All the specimens were observed at the occlusal and gingival margins and statistical analysis was performed. The results were as follows: 1. Groups filled with composite resin inlay showed less marginal leakage than the group directly filled(p<0.01). 2. There was no significant difference in marginal leakage between composite resin inlay groups luted with Adhesive bond followed by Adhesive cement and the group luted with All bond followed by Adhesive cement(p>0.05). 3. At occlusal margins, Composite resin inlay group luted with Adhesive bond followed by Adhesive cement showed less marginal leakage than the group luted with Fuii ionomer type I(p<0.01). At gingival margins, composite resin inlay group luted with All bond followed by Adhesive cement showed less marignal leakage than the group luted with Fuji ionomer type I(P<0.01).

• 디지털융복합연구
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• 제19권9호
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• pp.75-81
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• 2021

본 연구의 목적은 기업에서 클라우드 컴퓨팅 서비스를 채택하기 전에 판단 해야하는 중요한 요인들에 대한 우선 순위를 도출하고 평가한다. 연구 방법으로 전문가들에 대한 의사결정 사항을 반영하기 위해서 AHP 분석기법을 활용하였다. AHP는 복잡한 의사결정 문제를 계층적으로 표현하고 그 계층의 항목 간의 쌍대비교(Pairwise comparison)를 통하여 최선의 대안을 도출해 내는 의사결정 기법이다. 기존의 통계적 의사결정 기법들과 비교해 의사결정과정이 체계적이며 간단하여 이해하기가 쉽다. 또한 분석과정에서 의사결정자의 일관성을 판단할 수 있는 지표를 제공하여 절차 또한 합리적이다. 본 연구의 분석 결과 중요도 우선순위 항목으로 보안성, 신뢰성, 경제성 순으로 나타났다. 보안성의 하위 항목요인 중 제1순위는 접근권한의 통제성, 2순위는 외부위협의 안전성으로 도출되었다. 연구 결과가 추후 실무에서 기준으로 활용될 수 있는 방안으로 활용되는데 이바지할 수 있으며, 향후 클라우드 컴퓨팅 서비스 채택을 한 기업의 만족도를 평가하여 비교·분석하는 연구를 진행할 필요가 있다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제24권1호
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• pp.57-65
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• 2024

Background: The objective of behavioral guidance is to establish effective communication that aligns with a child's requirements to manage disruptive behavior. This study aimed to evaluate the effectiveness of the Tell-Show-Do and Ask-Tell-Ask techniques in managing dental anxiety in children during their initial appointment. Methods: The study included 50 children (28 boys and 22 girls) without any prior experience between the ages of 7 and 11 at their first dental visit. The children were randomly categorized into two groups: Group 1, Tell Shows Do, and Group 2, Ask-Tell-Ask. Subsequently, all children underwent noninvasive treatment procedures such as restorations, sealants, and oral prophylaxis. Furthermore, behavioral management techniques were employed based on the allocated group. Finally, anxiety levels for all children were assessed using the Raghavendra, Madhuri, and Sujata Pictorial Scale (RMS-PS) and heart rate at three different intervals (before, during, and after). The obtained data were entered into Microsoft Excel, and statistical analysis was performed using SPSS software. A paired t-test and Mann-Whitney U-test were used to compare the mean and median values of the two groups and determine their effectiveness. Results: Children in the TSD group exhibited statistically significant heart rates and RMS-PS scores in intra-group comparisons. However, children in the ask-tell-ask group showed a significant reduction only in the RMS-PS scores (P < 0.001) but not in the measures used to assess heart rate (P < 0.001). Conclusion: Tell-Show-Do was more effective than ask-tell-ask in alleviating dental anxiety in children. The simultaneous application of these two strategies can synergistically alleviate dental anxiety during a child's initial dentist appointment.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.419-424
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• 2020

This study analyzes the new GMCF method applied by the company with the aim to find out how the production of Accounting Information Systems (AIS) implemented by the company can be managed properly. The study also seeks to find out whether the company needs new system support facilities to facilitate the production performance reporting process of each division and evaluate the performance of GMCF systems in the company. The methods used are descriptive analysis techniques and statistical tests of Paired Sample T-Test comparison; this study uses production data of each unit of a product with random sampling to determine the level of product damage and compare production with the GMCF system and prior to using it. The results of the analysis found that the application of goods mutation control forms (GMCF) greatly influenced the smooth production reporting process, which resulted in an increase in achieving production targets and reducing the risk of product damage during the production process. The company also benefits from the efficiency of production costs when using the GMCF system and can quickly design policies for products that are damaged during the production process. In addition, the company can have damaged products repaired faster than before.

• PNF and Movement
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• 제13권1호
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• pp.9-16
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• 2015

Purpose: This study aimed to examined the effects of upper and lower limb coordinated exercise of proprioceptive neuromuscular facilitation (PNF) on static and dynamic balance ability. Methods: The subjects of this study were 18 patients who had been diagnosed with a stroke and hospitalized and who had received rehabilitation treatment at D rehabilitation hospital located in J city. They were randomly and equally assigned to a PNF upper and lower limb coordinated exercise group and an ordinary central nervous system development and treatment group, and they conducted exercises for eight weeks. They carried out exercise three times per week, for 30 minutes per each time. After each four minutes of exercise, each participant was given a and rest for one minute after exercise for four minutes was given. In order to test the subjects' static and dynamic balance ability and their dynamic balance ability, frailty and injuries,: a cooperative studyies of intervention techniques (FICSIT-4) test, a four- step square test (FSST), a timed up and go test (TUG), and a TWT3M tests wasere conducted before and after the exercise. Descriptive statistics were taken for the general characteristics of the subjects, and an independent t-test was conducted both before and after the exercise in order to examine differences between the two groups before and after the exercise were conducted. The A statistical significance level was set at p= 0.05. Results: In all the tests (of FICSIT-4, FSST, TUG, and TWT3M), both the experimental group and the control group saw more improved results, but the experimental group's results were significantly higher than those of the control group, and the size of the effects was larger in the experimental group than in the control group, with statistically significant results. Conclusion: PNF upper and lower limb coordinated exercise applied to chronic stroke patients produced brought significant results in static and dynamic balance ability. PNF and is considered as an important intervention program to improve stroke patients' balance ability.

• Journal of Korean Dental Science
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• 제9권2호
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• pp.55-62
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• 2016

Purpose: Alveolar bone develops with tooth eruption and is absorbed following tooth extraction. Various ridge preservation techniques have sought to prevent ridge atrophy, with no superior technique evident. Collagen has a long history as a biocompatible material. Its usefulness and safety have been amply verified. The related compound, atelocollagen, is also safe and displays reduced antigenicity since telopeptides are not present. Materials and Methods: The current study evaluated whether the $Rapiderm^{(R)}$ atelocollagen plug (Dalim Tissen, Seoul, Korea) improves tissue healing of extraction sockets and assessed the sequential pattern of bone regeneration using histology and microcomputed tomography in six beagle dogs. To assess the change of extraction socket, hard tissues were examined 2, 4, 6, and 8 weeks after tooth extraction. Result: The experimental groups showed better bone fill with slow remodeling process compared to the control groups although there was no statistical difference between groups. Conclusion: The atelocollagen seems to have a tendency to slow bone remodeling in the early phase of healing period and maintain remodeling capacity until late phase of remodeling. Also, use of atelocollagen increased the bone-to-tissue ratio compared to healing of untreated extraction socket.