• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.37-46
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• 2007

The C-shaped canal system is an anatomical variation mostly seen in mandibular second molars, although it can also occur in maxillary and other mandibular molars. The main anatomical feature of C-shaped canals is the presence of fins or web connecting the individual root canals. The complexity of C-shaped canals prevents these canals from being cleaned, shaped, and obturated effectively during root canal therapy, and sometimes it leads to an iatrogenic perforation from the extravagant preparation. The purpose of this study was to provide further knowledge of the anatomical configuration and the minimal thickness of dentinal wall according to the level of the root. Thirty extracted mandibular second molars with fused roots and longitudinal grooves on lingual or buccal surface of the root were collected from a native Korean population. The photo images and radiographs from buccal, lingual, apical direction were taken. After access cavity was prepared, teeth were placed in 5.25% sodium hypochlorite solution for 2 hours to dissolve the organic tissue of the root surface and from the root canal system. After bench dried and all the teeth were embedded in a self-curing resin. Each block was sectioned using a microtome (Accutom-50, Struers, Denmark) at interval of 1 mm. The sectioned surface photograph was taken using a digital camera (Coolpix 995, Nikon, Japan) connected to the microscope. 197 images were evaluated for canal configurations and the minimal thickness of dentinal wall between canal and external wall using 'Root Thickness Gauge Program' designed with Visual Basic. The results were as follows : 1. At the orifice level of all teeth, the most frequent observed configuration was Melton's Type C I (73%), however the patterns were changed to type C II and C III when the sections were observed at the apical third. On the other hand, the type C III was observed at the orifice level of only 2 teeth but this type could be seen at apical region of the rest of the teeth. 2. The C-shaped canal showed continuous and semi-colon shape at the orifice level, but at the apical portion of the canal there was high possibility of having 2 or 3 canals 3. Lingual wall was thinner than buccal wall at coronal, middle, apical thirds of root but there was no statistical differences.

• The KIPS Transactions:PartB
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• v.13B no.5 s.108
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• pp.561-568
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• 2006

WPS(Wearable Personal Station) for next generation PC can define as a core terminal of 'Ubiquitous Computing' that include information processing and network function and overcome spatial limitation in acquisition of new information. As a way to acquire significant dynamic gesture data of user from haptic devices, traditional gesture recognizer based on desktop-PC using wire communication module has several restrictions such as conditionality on space, complexity between transmission mediums(cable elements), limitation of motion and incommodiousness on use. Accordingly, in this paper, in order to overcome these problems, we implement hand gesture recognition system using fuzzy algorithm and neural network for Post PC(the embedded-ubiquitous environment using blue-tooth module and WPS). Also, we propose most efficient and reasonable hand gesture recognition interface for Post PC through evaluation and analysis of performance about each gesture recognition system. The proposed gesture recognition system consists of three modules: 1) gesture input module that processes motion of dynamic hand to input data 2) Relational Database Management System(hereafter, RDBMS) module to segment significant gestures from input data and 3) 2 each different recognition modulo: fuzzy max-min and neural network recognition module to recognize significant gesture of continuous / dynamic gestures. Experimental result shows the average recognition rate of 98.8% in fuzzy min-nin module and 96.7% in neural network recognition module about significantly dynamic gestures.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.139-144
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• 2000

This study was conducted to obtain the basic information to increase the practical use of soil survey data through the subdividing of valley shapes with soil sequences due to different parent rocks, and to study the relationship between the valley shapes and parent rock. The various rocks such as sedimentary(gray shale and sand stone) and igneous rocks(granite, granite gneiss and andesite porphyry) which are the major parent rocks in Yeongnam area were investigated. The characteristics of valleys formed and the kinds of soils derived from different rocks were analysed by using aerial photographs and topographical maps scaled 1:5,000. The rill density in igneous rock area was as high as 40. But the rill bifurcation ratio of first order stream was higher in the sedimentary than the igneous rocks except granite area. The mean slope of valleys in igneous areas was about 8%, which was higher than that of the sedimentary areas. The variability of valley width in the complexly metamorphosed rock, such as granite gneiss, and andesite porphyry, was greater than in sedimentary and in granite rocks. Based on the variability of valley widths and valley slopes, it was possible to classify the valleys into two types. The "Uterus-shaped valleys" had wide variability of valley width and were located in the areas of granite gneiss and andesite porphry rocks. while the "Roots-shaped valleys" had narrow variability of valley width and were located in the sedimentary areas. "Uterus-shaped valleys" were typified by having land forms of mountain foot slopes and alluvial fans, and the soil drainage sequences also had complexities. So that, we concluded that the variability of valley width and valley slopes was associated with kinds of parent rocks and metamorphism which influences soil sequence and characteristics.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.2
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• pp.49-58
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• 2019

There have been studies on the satisfaction, preference, and post occupancy evaluation of urban parks in order to reflect users' preferences and activities, suggesting directions for future park planning and management. Despite using questionnaires that are proven to be affective to get users' opinions directly, there haven been limitations in understanding the latest changes in park use through questionnaires. This study seeks to address the possibility of utilizing the thirdgeneration SNS data, Instagram and Google, to compare behavior patterns and trends in park activities. Instagram keywords and photos representing user's feelings with a specific park name were collected. We also examined reviews, peak time, and popular time zones regarding selected parks through Google. This study tries to analyze users' behaviors, emerging activities, and satisfaction using SNS data. The findings are as follows. People using park near residential areas tend to enjoy programs being operated in indoor facilities and to like to use picnic places. In an adjacent park of commercial areas, eating in the park and extended areas beyond the park boundaries is found to be one of the popular park activities. Programs using open spaces and indoor facilities were active as well. Han River Park as a detached park type offers a popular venue for excercises and scenery appreciation. We also identified companionship characteristics of different park types from texts and photos, and extracted keywords of feelings and reviews about parks posted in $3^{rd}$ generation SNS. SNS data can provide basis to grasp behavioral patterns and satisfaction factors, and changes of park activities in real time. SNS data also can be used to set future directions in park planning and management in accordance with new technologies and policies.

• The Korean Journal of Archival Studies
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• no.20
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• pp.77-114
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• 2009

The actual conditions of the labor unions are primitive. First, there is no good records management regulation. At this research, I found it that most regulations of the labor unions were all the same. I think they have been copied a kind of one of originality. Second, the definition of records were very narrow, like documentary evidence. Third, the classification, filing, disposal regulations are the below level of the public institution in 1970s. Fourth, there are no standards of the records scheduling for the labor records. What kind of labor records have the historical values? I could not find, only the documentary evidence value. So, I think The actual conditions of the labor unions are primitive. I investigated the collections of the Southern Labor Archives in USA. There were many kind of records. For example, the records of regional labor unions also central labor unions, pamphlets, journals, photos, personal records, oral history, organizational records like protocols article of associations internal rules, minute books etc. Like this the collections of the Southern Labor Archives in USA are very various. But our actual conditions of the labor unions is far from that. Rather, we just have tried collected records for publishing the white papers. But this habitual practice would not be desirable. Because they must manage the records from the producing time. Mostly, 'laborer history HANNAE' were organised, and they are trying the collecting and management of the labor records. Also They are trying the computerizing, compilation. 'HANNAE' has the condition for the transformation of the labor archives. But if they want to be really, they must make the records management infra and so, should normalize the record management firstly. For example, They must be keep the standardized records management regulations, records scheduling redesigned. the developing standard model for the records management. And they have the vision for the hub of the labor archives. When coming to this, it will be realized the labor archives Now the records for the working class are disappearing. The managing the records for the labor is another labor movement. All together should join it. But I think the supporting of the archival science research colleagues will be the essential part.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.127-133
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• 2019

Purpose: The purpose of present study was to investigate fracture strength and mode of failure of endodontically treated teeth restored with metal cast post-core system, prefabricated fiber post system, and newly introduced polyetherketoneketone (PEKK) post-core system. Materials and methods: A total of 21 mandibular premolar were randomly grouped into 3 groups of 7 each according to the post material. Group A was for metal cast post core; Group B for prefabricated glass fiber post and resin core; and Group C for milled PEKK post cores. All specimens were restored with metal crown. The fracture strength of each specimen was measured by applying a static load of 135-degree to the tooth at 2 mm/min crosshead speed using a universal testing machine. After the fracture strength measurement, the mode of failure was observed. The results were analyzed using Kruscal-Wallis test and post hoc Mann-Whitney U test at confidence interval ${\alpha}=.05$. Results: Fracture resistance of PEKK post core was lower than those of cast metal post and fiber reinforced post with composite resin core. In the aspect of fracture mode most of the root fracture occurred in the metal post core, whereas the post detachment occurred mainly in the fiber reinforced post. In the case of PEKK post core, teeth and post were fractured together. Conclusion: It is necessary to select appropriate materials of post for extensively damaged teeth restoration and clinical application of the PEKK post seems to require more research on improvement of strength.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.2
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• pp.118-126
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• 2019

Purpose: This research is to investigate factors that affect dental aesthetics and analyze whether individual perception affects and difference of genders affects the esthetic factors. Materials and methods: Seventy dental students of Chonnam University aged from 25 to 35 years old without periodontal problems were included. Maxillary dental cast for participants were made, and standardized photo was taken with a digital camera. Maximum visual width and the position of gingival zenith of maxillary anterior teeth and maximum height of the maxillary central incisors were measured by a measurement program and the shape of central incisor was categorized. Questionnaire was conducted to evaluate esthetic perception. SPSS program was used to perform statistical analysis. Results: The average visual width ratio of right maxillary anteriors was 1.38:1:0.78 and 1.41:1:0.81 for the left which differ from the golden ratio. The width to height ratio for right and left central incisor was 0.84 and 0.83 respectively. The gingival zenith position was determined to be: mostly, central incisors and canines were located in the distal side, lateral incisors were located in the center. The visual width ratio of right maxillary anterior teeth, ratio of width to height of central incisor, gingival zenith position, crown morphology and amounts of gingival exposure upon smiling were not significantly different between genders, and facial patterns and these dental esthetic factors were not related to aesthetic perception. Conclusion: Even though participants had the visual width ratio of maxillary anteriors or ideal width to ideal height of central incisors that did not agree with the golden ratio, they had high satisfaction for dental esthetics. Esthetic perception depends more on subjective judgements of participants than objective indices.

• Journal of Communication Design
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• v.55
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• pp.240-249
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• 2016

This study focused on cases about user experience using digital media as a marketing. The recent convergence of various types of media is resulting in new types of content. In a situation where approaching consumers through digital and virtual means is no longer an alternative or an option but a necessity, customers must be influenced and stimulated using various types of digital media. Because modern consumers prefer to participate actively rather than to be passively exposed to information, there is a need to maximize and optimize the consumer's experience using digital media. In this research, consumer experiences that utilized digital media were examined, and these case studies were analyzed from an experiential marketing perspective. How the 5 different types of Experiential Marketing proposed by Bernd Schmitt and Digital medias were combined in the digital marketing campaigns was examined. The case studies analyzed in this research were chosen out of widely popular digital marketing campaigns ran by beauty brands that used various experimental marketing types, such as 'Make-up Genius' of L'Or?al, 'Google Glass Tutorials' of Yves Saint Laurent and 'Digital Runway Bar' of The Burberry Beauty Box. This study classified that case samples into paid media, earned media and owned media based on sense, feel, think, act and relate that are the strategic experiential modules of Bernd Schmitt. This study could be confirmed various customer experience as a sense, feel, think, act and relate through that cases using digital media technology and marketing element of digital media. Through the process of examining which digital media types each marketing campaign utilized and how these types of digital marketing were combined, this research is significant in that it helps for the understanding of the current state of digital marketing and in that it can serve as the foundation for future research of efficient digital marketing.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.717-731
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• 2021

We analyzed the characteristics of the habitat environment for the Seonam study area in Ulsan, the southern shore of the East Sea using bathymetry and seafloor environment data. The depth of the study area ranges from about 0 m to 23 m. In the west of the study area, the water depth is shallow with a gentle slope, and the water depth becomes deeper with a steep slope in the east. Due to the right-lateral strike-slip faults located in the continental margin of the East Sea, the fracture surfaces of the seabed rocks are mainly in the N-S direction, which is similar to the direction of the strike faults. Three seafloor types (conglomeratic-grained sandy, coasre-graiend sandy, fine-grained sandy) and rocky bottom area have been classified according to the analyses of the bathymerty, seafloor image, and surface sediment data. The rocky bottom areas are mainly distributed around Seaoam and in the northern and southern coastal area. But the intermediate zone between Seonam and coastal area has no rocky bottom. This intermediate area is expected to have active sedimentation as seawater way. The sandy sediments are widely distributed throughout the study area. Underwater images and UAV images show that Cnidarians, Brachiopods, Mollusks are mostly dominant in the shallow habitat and various Nacellidae, Mytilidae live on the intertidal zone around Seonam. Annelida and Arthropod are dominant in the sandy sediments. The distribution of marine organism in the study area might be greatly influenced by the seafloor type, the composition and particle size distribution of the seafloor sediments. The analysis of habitat environment mapping with bathymetry, seafloor data and underwater images is supposed to contribute to the study of the structure and function of marine ecosystem.

• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.71-77
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• 2020

Purpose: To determine if sparing the interspinous and supraspinous ligaments during posterior decompression for lumbar spinal stenosis is significant in preventing postoperative spinal instability. Materials and Methods: A total of 83 patients who underwent posterior decompression for lumbar spinal stenosis between March 2014 and March 2017 with a minimum one-year follow-up period, were studied retrospectively. The subjects were divided into two groups according to the type of surgery. Fifty-six patients who underwent posterior decompression by the port-hole technique were grouped as A, while 27 patients who underwent posterior decompression by a subtotal laminectomy grouped as B. To evaluate the clinical results, the Oswestry disability index (ODI), visual analogue scale (VAS) for both back pain (VAS-B) and radiating pain (VAS-R), and the walking distance of neurogenic intermittent claudication (NIC) were checked pre- and postoperatively, while simple radiographs of the lateral and flexion-extension view in the standing position were taken preoperatively and then every six months after to measure anteroposterior slippage (slip percentage), the difference in anteroposterior slippage between flexion and extension (dynamic slip percentage), angular displacement, and the difference in angular displacement between flexion and extension (dynamic angular displacement) to evaluate the radiological results. Results: The ODI (from 28.1 to 12.8 in group A, from 27.3 to 12.3 in group B), VAS-B (from 7.0 to 2.6 in group A, from 7.7 to 3.2 in group B), VAS-R (from 8.5 to 2.8 in group A, from 8.7 to 2.9 in group B), and walking distance of NIC (from 118.4 m to 1,496.2 m in group A, from 127.6 m to 1,481.6 m in group B) were improved in both groups. On the other hand, while the other radiologic results showed no differences, the dynamic angular displacement between both groups showed a significant difference postoperatively (group A from 6.2° to 6.7°, group B from 6.5° to 8.4°, p-value=0.019). Conclusion: Removal of the posterior ligaments, including the interspinous and supraspinous ligaments, during posterior decompression of lumbar spinal stenosis can cause a postoperative increase in dynamic angular displacement, which can be prevented by the port-hole technique, which spares these posterior ligaments.