• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.418-435
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• 2001

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.1
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• pp.21-30
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• 2017

Soil erosion has been issued in many countries since it causes negative impacts on ecosystem at the receiving water bodies. Therefore best management practices to resolve the problem in a watershed have been developed and implemented. As a prior process, there is a need to define soil erosion level and to identify the area of concern regarding soil erosion so that the practices are effective as they are designed. Universal Soil Loss Equation (USLE) were developed to estimate potential soil erosion and many Geographic Information System (GIS) models employ USLE to estimate soil erosion. Sediment Assessment Tool for Effective Erosion Control (SATEEC) is one of the models, the model provided several opportunities to consider various watershed peculiarities such as breaking of slope length, monthly variation of rainfall, crop growth at agricultural fields, etc. SATEEC is useful to estimate soil erosion, however the model can be implemented with ArcView software that is no longer used or hard to use currently. Therefore SATEEC based on ArcView was rebuild for the ArcGIS software with all modules provided at the previous version. The rebuilt SATEEC, ArcSATEEC, was programmed in ArcPy and works as ArcGIS Toolset and allows considering monthly variations of rainfall and crop growth at any watershed in South-Korea. ArcSATEEC was applied in Daecheong-dam watershed in this study, monthly soil erosion was estimated with monthly rainfall and crop growth variation. Annual soil erosion was computed by summing monthly soil erosion and was compared to the conventional approach to estimate annual soil erosion. The annual soil erosion estimated by the conventional approach and by summing monthly approach did not display much differences, however, ArcSATEEC was capable to provide monthly variation of soil erosion.

• International Commerce and Information Review
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• v.14 no.4
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• pp.387-408
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• 2012

This paper have examined the descriptive and legal approaches to the comparison and analysis of major content of direct transport in FTA rules of origin and the primary judicial precedents that arose during the executing process of FTAs. Preferential tariff treatment shall be applied to a good satisfying the requirement of this agreement(annex, article etc.,) and which is transported directly between the territories of the exporting party and importing party. However, products may be transported through territories of non-parties, provided that they do not undergo operations other than unloading, reloading, splitting-up of consignments or any operation designed to preserve them in good condition. During this period the products shall remain under customs control in the country of transit. The low perception of firms on the rules of origin was found to lead to breaking the rule and thus taking up losses. The FTA major countries enacted penalty rules against the violation of the rules of origin and bring civil and criminal suits and administrative sanctions. The types and level of penalties are subject to their domestic laws of each of those nations. With better recognition of major content of direct transport in FTA rules of origin and well-prepared countermeasures, firms will be able to enhance competitive advantage while benefiting from preferential tariffs.

• Journal of Conservation Science
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• v.37 no.5
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• pp.536-544
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• 2021

In the present study, safe management and value improvement of bamboo sunblind, which is an item of cultural heritage, were performed by adopting stable conservation treatment methods. The bamboo sunblind used in the present study was excavated from No. 1 catchment site in Baesanseongji, Busan. It was determined that the main material used to make the sunblind was bamboo, and herbal plants were used to weave the bamboo using lacquer as an adhesive agent. All contaminants and soil adhered to the sunblind was removed. Thereafter, the sunblind, which was recovered in the form of blocks, was washed separately after fixing it to a temporary plaster frame and to avoid the blocks from breaking during washing. Then, polyethylene glycol (PEG) impregnation was utilized for the reinforcement treatment. Based on the preliminary test results, the shape of the sunblind was fixed using a stainless-steel frame to prevent physical damage that may occur during the drying process. Thereafter, the bamboo sunblind was vacuum freeze-dried. PEG 20% (in ethyl alcohol) was applied as a surface treatment agent for stabilization the sunblind. After the surface treatment, the bamboo sunblind were joined together to fit the maximum width, and the rectangular shape of the sunblind was restored-as best as possible-while filling in the missing parts by maximizing the use of unknown members such as in the disturbed layers below bamboo sunblind surface. The conservation treatment was completed by fixing the bamboo sunblind into the fabricated frame.

• 재활복지
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• v.17 no.4
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• pp.339-370
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• 2013

This study is to suggest necessary improvements of inconvenient elements as well as the ergonomic design standard to develop disabled cars by evaluating the types of needs and observing the behavior characteristics on their car use and the survey on the complaints of the disabled drivers and their guardians in the use of disabled car. The results of this study are as follows. First, both the disabled drivers and their guardians are found to feel high inconvenience and low satisfaction with the cars they use now. Second, the disabled owner-drivers also answered in a same way as guardians. They find the most difficulty in moving the supporting equipment to get into and out of a car. Both the owner-drivers with disabilities and guardians complained of lack of handiness they face when they wear the seat belts and sitting on the seats. In view of this, a disabled car to be developed should have ergonomic design for its seats and the safety of the seatbelt as well as trouble-free supporting equipment helping them move. Third, rather than owner-drivers with handicaps, guardians expressed more difficulties and less contentment with the cars for the disabled, which is reckoned to lead to the changes of perspectives on development of cars for the disabled breaking away from existing viewpoints focusing on the accessibility to the vehicles. Fourth, both owner-drivers and guardians showed higher interests in driving and other safety and convenience measures than in using supporting equipment to get into and out of vehicles, implying that rather than the accessibility to get into and out of a car, convenience should primarily be taken into account for the design of the disabled car. Fifth, the auto-manufacturer is to give prior thought to user convenience when developing a car in practice. For this, the developer may have the disabled car users join the process of development as well as asking experts for help and participation.

• Korean Journal of Heritage: History & Science
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• v.42 no.4
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• pp.172-197
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• 2009

The stone stupas of the Mireuk Temple Site and Jeongnim Temple Site were the beginning of Korean stone stupa and the unique ones stemming from the Baeje period. Therefore, the work of investigating the characteristics of these two stone stupas would give us a basis for understanding Korean stone stupas in a large scale and Baekje-style stone stupas in a narrow sense. As shown in some records, the excellent architectural skills of Baekje could be known by the fact that Abiji was invited to the building of Hwangryong Wooden stupa, one of the national undertakings of Shilla and the skills and styles related to stone stupas were thought to be disseminated in this process. However, it has not been very convincing that the stone stupas with Baekje styles were disconnected in an instant with the unification of Shilla, in terms that culture and art would inherited and developed. The current academic circle set a frame and defined all these types of stone stupas as Baekje-system stone stupas built in Goryeo period and put them in a uniformly chronological order. The popularization of Buddhism, support of regionally powerful clans and cultural revival were suggested as the factors of their appearance, but it seemed difficult to be assured that these led Baeje-style stone stupas to reappear in a moment by breaking the gap of about 300 years. Of course, it has not been active in Gyeongju area, but they have greatly influenced the stone stupas of Shilla; therefore, it would be possible to consider that they were developed but limited to certain areas. This study focused on the starting point of such development and investigated the formation of Baeje-style stone stupas through the stone stupas of the Mireuk Temple Site and Jeongnim Temple Site and their subsequent development through Wanggung-ri Stone Stupa.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.115-130
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• 2022

Barrage is an interactive method based on video, and the video itself is visualized from the viewer's point of view to play people's emotions, and it already has an advantage in communication by attracting people's attention using stories and plays. Advances in digital and mobile technology have enabled video viewing anytime, anywhere. Due to the nature of the barrage site that relies on the same video content or playback to participate in video sharing through computers or mobile clients, a barrage that can express users' feelings and thoughts will be added, breaking down the limit of content acceptance by a single user. Barrage satisfy users' entertainment needs, and their influence is growing. Gradually, they are heading to offline movie theaters and TV from barrage videos on the Internet. Attempts to function as offline ammunition facilitated technological innovation for media convergence by converging mobile media with PCs and screens. At the same time, the trend of media convergence shown by coal screens is also a trend of overall technological development. A barrage is an extension of human communication skills. The properties of the barrage fit well with the need for experiential marketing (via video). It can provide a visual experience and create an atmosphere of "surrounding and watching" and eliminate loneliness. Barrage itself provides a function to comment on videos, which is a trigger point for the reason, and donation adds to the amount of information in the video, adding to the fun of the video. Through the barrage, sarcastic, teasing, and expressing emotions can bring entertainment experiences, and users can produce and communicate their shooting text while consuming the satisfaction brought by the shooting. At the same time, Barrage attaches great importance to the needs of the masses, is more individual and diversified, and has commercial significance in line with the current development trend of the Internet. As a new interactive method, barrage contains huge potential value. However, the impact of the interactive way of barrage should also be viewed from a dialectical point of view, how to solve the difficulties in the development of barrage. The way to solve the difficulties in the development of barrage is worth studying. This research will analyze the reasons for the development of barrage and the analysis of Chinese barrage websites, the case analysis of barrage videos, the exploration of the characteristics and values of barrage, and the problems in the process of barrage communication. Provide reference for the development of industrial culture.

• Korean Journal of Legislative Studies
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• v.27 no.2
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• pp.5-40
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• 2021

In the 4.7 by-election in 2021, the ruling Democratic Party suffered a record devastating defeat, breaking the trend of a post-intermediate evaluation confirmed in the recent election. Why did the Democratic Party lose by a large margin unlike the recent election trend? In order to find answers to these questions, this study analyzes the voting behavior of individual voters based on the voter consciousness survey data conducted after the 4.7 by-election, while examining the background and causes of such voter choices. As a result of the study, in the 4.7 by-election, as confirmed in previous studies, public opinion against the ruling government was strong, and negative elections were held. However, if we look at the process and results of this by-election in more detail, we can see that it is different from the general by-election. In the past by-elections, the government judgement was due to the passive participation of the ruling party-oriented voters in elections with low political weight, or the active judgement psychology that was maximized in situations where the political burden was less. However, in this by-election, on the contrary, in an election with a high political weight, the active judgement psychology of the Democratic Party and non-partisan voters had an effect on strengthening the midterm evaluation character of the election. In addition, it can be seen that the gathering of conservative voters who support the opposition also had a strong influence on the reinforcement of the midterm evaluation character of the election.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.95-109
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• 2008

We numerically analyzed the nonlinear shoaling, a plunging breaker and its accompanying energetic suspension of sediment at a bed, and a redistribution of suspended sediments by a down rush of preceding waves and the following plunger using SPH with a Gaussian kernel function, Lagrangian Dynamic Smagorinsky model (LDS), Van Rijn's pick up function. In that process, we came to the conclusion that the conventional model for the tractive force at a bottom like a quadratic law can not accurately describe the rapidly accelerating flow over a swash zone, and propose new methodology to accurately estimate the bottom tractive force. Using newly proposed wave model in this study, we can successfully duplicate severely deformed water surface profile, free falling water particles, a queuing splash after the landing of water particles on the free surface and a wave finger due to the structured vortex on a rear side of wave crest (Narayanaswamy and Dalrymple, 2002), a circulation of suspended sediments over a swash zone, net transfer of sediments clouds suspended over a swash zone toward the offshore, which so far have been regarded very difficult features to mimic in the computational fluid mechanics.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.137-158
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• 2009

This study is to find the causes of the current situations of conflict between generations in regards to succession of their family farm, for the target group of graduates Korea National Agricultural College of the year 2008 and their parents. This study aims at finding a way of controlling and solving the conflicts, and of developing a course of education and training, so that through this process they can come to a rational conclusion to the conflicts that arise regarding succession of the farm, in a climate of harmony and peace. It is found that communication between parents and graduates has normally gone on well, but specific problems related to management of the farm are often present. Furthermore, there is often lack of trust and promise between the parties which often causes difficulties in preparation for the succession of the farm. On the basis of these observation, we have designed and implemented an education workshop and training, as a program in which parents and their successors participated. As a result, we found it to be very effective, but it was also found to be in need of some changes. The workshop is to be implemented in two separate stages. The first stage should focus on communication and trust between family members. Firstly, they are given the opportunity to share the list of concerns withone another, as an ice breaking activity. Secondly, they can present their own hopes or wishes. And lastly, they can communicate with one another in an effort to find resolutions that will be keep both parties satisfied. The second stage should be aimed at establishing agreements concerning succession of the farm in a harmonious and peaceful manor; the second stage is also an opportunity to discuss 'Farm management and succession'. The Korea National Agricultural College (KNAC) is in the pursuit of fostering agricultural CEO's for the future of Korea. KNAC is currently implementing a very unique system of interviews in which parents participate together with students, in order to help them make a plan for rational management of their farm and smooth succession of the farm. Although KNAC now has students present a blueprint of their own unique business plans as a graduation thesis, it is necessary for KNAC to complement this system with education and training regarding the succession of family farms. Furthermore, KNAC should also develop an education and training program that is separate for this purpose, and make it a regular course of study of KNAC in the future.