• Title/Summary/Keyword: Rock Support

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Prediction of rock slope failure using multiple ML algorithms

  • Bowen Liu;Zhenwei Wang;Sabih Hashim Muhodir;Abed Alanazi;Shtwai Alsubai;Abdullah Alqahtani
    • Geomechanics and Engineering
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    • v.36 no.5
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    • pp.489-509
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    • 2024
  • Slope stability analysis and prediction are of critical importance to geotechnical engineers, given the severe consequences associated with slope failure. This research endeavors to forecast the factor of safety (FOS) for slopes through the implementation of six distinct ML techniques, including back propagation neural networks (BPNN), feed-forward neural networks (FFNN), Takagi-Sugeno fuzzy system (TSF), gene expression programming (GEP), and least-square support vector machine (Ls-SVM). 344 slope cases were analyzed, incorporating a variety of geometric and shear strength parameters measured through the PLAXIS software alongside several loss functions to assess the models' performance. The findings demonstrated that all models produced satisfactory results, with BPNN and GEP models proving to be the most precise, achieving an R2 of 0.86 each and MAE and MAPE rates of 0.00012 and 0.00002 and 0.005 and 0.004, respectively. A Pearson correlation and residuals statistical analysis were carried out to examine the importance of each factor in the prediction, revealing that all considered geomechanical features are significantly relevant to slope stability. However, the parameters of friction angle and slope height were found to be the most and least significant, respectively. In addition, to aid in the FOS computation for engineering challenges, a graphical user interface (GUI) for the ML-based techniques was created.

The prosthetic approach and principle for an collapsed VDO ; A clinical case of pseudo Class III patient (저위교합환자의 보철적 접근법과 이론 : Pseudo Class III 교합환자 증례)

  • Kwon, Kung-Rock;Choi, Dae-Gyun
    • Journal of Dental Rehabilitation and Applied Science
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    • v.20 no.2
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    • pp.121-134
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    • 2004
  • This article describes a clinical protocol for the conventional rehabilitation of patient diagnosed with partial anodontia. A combined dental therapy approach was used and included endodontic therapy and root capping on the maxillary central incisors, fabrication of a maxillary overdenture, and fabrication of mandibular konus overdenture supported by 3 konus abutments. Within this protocol, tooth-supported overdenture prostheses are used for 2 purposes: first, to obtain the most rigid retention and function at an established maxillary-mandibular relationship; and second, to continuously maintain function and esthetic appearance applying immediate dentures after teeth extraction. The idea behind this protocol and its associated clinical procedures is presented along with a discussion compared with implant therapy. In the case introduced, and after 7 years of observation, the therapy can be seen as a success. We increased the occlusal vertical height in this case, but it would be more appropriate to see this as recovering the occlusal vertical height that was lost. The process of increasing the occlusal vertical height, that is restoration of the face, modification of the extrinsic occlusion of the incisors, and retraction of the mandible is very difficult and important. Ultimately, class III malocclusion is fixed, adequate occlusal vertical height is gained, and the retracted posterior anodontial portion is restored by prosthodontic dentures based on the rigid support theory. The result of the therapy done on the later-achieved malocclusion with partial anodontia on the posterior portion must consider the following in order to maintain the safety of the esthetics of the tooth and face for a period of time: 1) occlusal restoration with an ideal occlusal vertical height, 2) allowance of the final occlusion induced by the functional relationship of the upper and lower jaw, 3)final occlusion functionally induced by the lip competence limit.

NOVEL TREATMENT MODALITY OF IMPLANT-RETAINED OVERDENTURE FOR IMMEDIATE FUNCTION IN COMPLETELY EDENTULOUS PATIENTS (무치악 환자에서 하악 임플랜트 지지 피개의치에 의한 즉시 하중 부담에 관한 연구)

  • Kim, Jang-Wook;Kim, Hyeong-Seob;Baik, Jin;Kwon, Kung-Rock
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.1
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    • pp.34-47
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    • 2007
  • Statement of problem: Conventional mandibular complete denture lacks in support and stability for edentulous patients to use. Purpose: To enhance support and stability of mandibular complete denture, 2 implants were inserted on the inter-mental foramina space of edentulous patients. With 2 magnetic attachments on the inner side of the overdenture, we gave immediate loads and evaluated the stability of the implants, the responses of the supporting tissues, and the satisfaction of the patients. Material & methods: 6 edentulous patients (5 male, 1 female) each recieved 2 SLA implants in the inter-mental foramina region and implants were immediately loaded with overdenture with magnet attachments. To evaluate the implants stability and the peri-implant tissues, clinical exams, RFA tests and radiographic exams were preformed at the 1 week, 2wks, 6wks, 12wks, and 24wks. post- surgery. Results: The mean surgery time was $45.7{\pm}7.7mins$., while the denture delivery time was $45.5{\pm}12.6mins$. Only 2 of 14 implants were failed. Survived implants that remained were clincally and radiographically stable. Mean ISQ values were relatively stable, showing $69.71{\pm}5.55$, $69.00{\pm}9.48$, $67.92{\pm}7.86$, $67.92{\pm}9.58$, $70.08{\pm}7.61$, $71.92{\pm}6.43$ at the 1 wk, 2 wks, 6 wks, 12 wks, 24 wks. follow up check. Crestal bone changes were $-1.18mm{\pm}0.68mm$, $-1.35{\pm}0.69mm$, $-1.47{\pm}0.68mm$ at the 6wks, 12wks, 24wks. follow up check. Bleeding on probing(BOP index) was not significant. Conclusion: Mandibular ovedentures with 2 magnetic attachments over two interforaminal implants on edentulous patients for immediate function is a recommendable novel treatment for edentulous patients which shows stability on the implants and supporting tissue.

A Basic Study for Single Shell Support System of Railway Tunnel (철도 터널의 싱글쉘 지보시스템 적용에 관한 기초 연구)

  • Jung, Daeho;Jeong, Cahnmook
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.1
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    • pp.39-48
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    • 2016
  • In this study, it can be shortened tunnel construction work period by introducing a single-shell tunnel does not placing the secondary concrete lining, a global research trend, reduction of the cost of the lining placement and number of benefits that can ensure the safety of long-term tunnel with a single shell it was to study the tunnel method. First, we analyze the design and construction practices relating to delete lining of the domestic design and construction practices and a comprehensive analysis of the stability study found a rock in good condition interval (1~3 grades), we propose that the lining uninstalled. In the case of domestic changes on the ground floor is very heavy underfoot conditions many so tunneling method by single shell as ground conditions are good and one preferred the water points that apply in less soil, the soil health and poor sections (4~5 grades) reflecting with respect to the concrete lining that is expected reasonable.

Comparison of Elastic Modulus Evaluated by Plate Load Test and Soil Stiffness Gauge Considering Strain and Ground Stiffness (변형률 및 지반강성을 고려한 평판재하시험과 흙강성측정기의 탄성계수 비교)

  • Kim, Kyu-Sun;Shin, Donghyun
    • Journal of the Korean Geotechnical Society
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    • v.38 no.10
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    • pp.31-40
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    • 2022
  • This study compares elastic moduli calculated using two stiffness testing methods with different strain ranges to evaluate the stress-settlement characteristics of foundation support layers. Elastic moduli were calculated by the soil stiffness gauge (SSG) in the micro-strain range and the plate load test (PLT) in the medium strain range. To apply the elastic moduli obtained by the two testing methods with different strain ranges to the design and construction of foundation soils, the correlation between each measurement value should be identified in advance. As a result of the comparative analysis of the elastic moduli calculated using the two methods in weathered soil and rock, which are representative support layers in Korea, the calculated elastic moduli differed depending on the types of soil and stress conditions. For various soil types, the static elastic modulus obtained by the PLT was reduced by 56% because of the difference in the strain level of the test compared with the dynamic elastic modulus obtained by the SSG. Therefore, the results show that it is necessary to apply corrections to the stress distribution, stress level, and dynamic effect according to the ground stiffness to effectively use the SSG instead of the PLT.

Gangneung Haksan Odokttegi Heritage and Performance Contents (강릉학산오독떼기유산과 공연콘텐츠)

  • Lee, Chang-Sik
    • (The) Research of the performance art and culture
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    • no.38
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    • pp.249-275
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    • 2019
  • Gangneung farm song is important for the ritualistic labortheatricals. Especially, in the theatrical process program, the songsof weeding, such as Haksan Odokkteggi and Ssadae, were alsoincluded to represent the agricultural ritualistic prayer for goodharvest. The use of Gangneung farm song is attractive in termsofthe circumstances. There is no chance of success as a plan simplyfor local events. As a comprehensive art, Gangneung farmsongshould simultaneously revitalize locality, representability andglobality. In this context, three directions are suggested dependingon the development progress. The second direction to the thirddirection are mainly oriented toward government-local authoritycentered support, but, in particular, the third direction should aimtobe an open archive in which the public and the contents prosumercan participate. In the production of the traditional content, OSMUmust be endlessly recreated and spread through 'diversity' and'interrelationships'. The contents utilization was discussed based on the transmissiondetails and analysis evidence of Gangneung Haksan Odokttegi. Thediversification of the way of performing farm song and the folk songs that can induce interest were proposed. Furthermore, basedon the fact that 12 songs classified into 8 work types, there-creation of the contents that focus on the playful aspect of theperforming arts was also proposed. In addition to suggestingthedesirable discourse of the performance groups, the experienceprogram development, education, public relations andcommunication reinforcement based on the narrating principlesoffarm songs, and the development and execution of farmsongprograms based on the tradition and the event demands wereproposed. While mentioning the necessity of value creation, thevitality of performing arts skills that put emotion, imagination, fun, sympathy, and etc. on the original form and the model of farmsongs should be supplemented to Gangneung Haksan Odokttegi. The independent transmission aspect of Gangneung Arirangisalso positive. There are difficulties of reduction of traditionalitydueto the designation, standardized transmission, lack of developmentof voluntary performances, and demonstration-centeredtransmission. Narrowly, we focused on the education andvitalization directions in terms of the capacity building of theconservation council itself. By embodying the essential value of theagricultural literature that farm songs possess, it can bringimpression of all worlds, all lives, communication and sharing, anddraw inspiration from the humanistic view of the world andemotion. The reconstitution of agricultural heritage, theconstruction of a storytelling linked with the concrete objects suchas Beomil National Preceptor, Gulsansa, FlagpoleSupport(Dangganjiju), Seokcheon, Hakbawi rock, and etc., andtheestablishment of fusion type farm song museum were proposed. In terms of culture industry, we requested active support fromtheinstitutions including local governments and various farmsongstorytelling creation projects.

Evaluation of bonding state of tunnel shotcrete using impact-echo method - numerical analysis (충격 반향 기법을 이용한 숏크리트 배면 접착 상태 평가에 관한 수치해석적 연구)

  • Song, Ki-Il;Cho, Gye-Chun;Chang, Seok-Bue
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.10 no.2
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    • pp.105-118
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    • 2008
  • Shotcrete is one of the main support materials in tunnelling. Its bonding state on excavated rock surfaces controls the safety of the tunnel: De-bonding of shotcrete from an excavated surface decreases the safety of the tunnel. Meanwhile, the bonding state of shotcrete is affected by blasting during excavation at tunnel face as well as bench cut. Generally, the bonding state of shotcrete can be classified as void, de-bonded, or fully bonded. In this study, the state of the back-surface of shotcrete is investigated using impact-echo (IE) techniques. Numerical simulation of IE technique is performed with ABAQUS. Signals obtained from the IE simulations were analyzed at time, frequency, and time-frequency domains, respectively. Using an integrated active signal processing technique coupled with a Short-Time Fourier Transform (STFT) analysis, the bonding state of the shotcrete can be evaluated accurately. As the bonding state worsens, the amplitude of the first peak past the maximum amplitude in the time domain waveform and the maximum energy of the autospectral density are increasing. The resonance frequency becomes detectable and calculable and the contour in time-frequency domain has a long tail parallel to the time axis. Signal characteristics with respect to ground condition were obtained in case of fully bonded condition. As the ground condition worsens, the length of a long tail parallel to the time axis is lengthened and the contour is located in low frequency range under 10 kHz.

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Geochemical Study on the Genesis of Chuncheon Nephrite Deposit (춘천 연옥의 기원에 관한 지구화학적 연구)

  • 박계현;노진환
    • The Journal of the Petrological Society of Korea
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    • v.9 no.2
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    • pp.53-69
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    • 2000
  • To reveal the origin of the Chuncheon nephrite deposit, radiogenic isotopes of Sr and Pb, stable isotopes of 0 and H, and rare earth elements concentrations were analyzed. Such geochemical data were integrated to track the stepwise changes during the various ore formation stages. All the samples from the nephrite deposit have significantly low 0 isotopic ratios compared with the marble from which they had been formed, which reflects the very important role of the crustal circulating water with low 6180 and 6D in every stage of ore formation. There were progressive decrease of 6180 and 6D during the genesis of Chuncheon nephrite deposit. Newly formed minerals during the ore formation reveal disequilibrium with existing minerals in the respect of 0 isotope, which suggests that the ore-forming fluid of circulating water origin was involved with significant water-rock ratios in every step of ore formation process. The ore samples have Sr and Pb isotopic ratios similar to the values of Kyeonggi gneiss complex within which the deposit is located, which also suggests the important role of crustal circulating water in the genesis of the deposit. In conclusion, all the geochemical data support that major portion of the ore-forming fluid of Chuncheon nephrite deposit was derived ultimately from the surface water of meteoric origin. The meteoric water supplied Sr and Pb through leaching the rocks surrounding the ore deposits.

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16S rDNA Analysis 9f Bacterial Diversity in Three Fractions of Cow Rumen

  • Cho, Soo-Jeong;Cho, Kye-Man;Shin, Eun-Chule;Lim, Woo-Jin;Hong, Su-Young;Choi, Byoung-Rock;Kang, Jung-Mi;Lee, Sun-Mi;Kim, Yong-Hee;Kim, Hoon;Yun, Han-Dae
    • Journal of Microbiology and Biotechnology
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    • v.16 no.1
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    • pp.92-101
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    • 2006
  • The bacterial diversity of the bovine rumen was examined using a PCR-based approach. 16S rDNA sequences were amplified and cloned from three fractions of rumen (solid, fluid, and epithelium) that are likely to represent different bacterial niches. A total of 113 clones were sequenced, and similarities to known l6S rDNA sequences were examined. About $47.8\%$ of the sequences had $90-97\%$ similarity to 16S rDNA database sequences. Furthermore, about $62.2\%$ of the sequences were $98-100\%$ similar to 16S rDNA database sequences. For the remaining $6.1\%$, the similarity was less than $90\%$. Phylogenetic analysis was also used to infer the makeup of the bacterial communities in the different rumen fractions. The Cytophaga-Flexibacter-Bacteroides group (CFB, $67.5\%$), low G+C Gram-positive bacteria (LGCGPB, $30\%$), and Proteobacteria $(2.5\%)$ were represented in the rumen fluid clone set; LGCGPB $(75.7\%)$, CFB$(10.8\%)$, Proteobacteria $(5.4\%)$, high G+C Gram-positive bacteria (HGCGPB, $5.4\%$), and Spirochaetes $(2.7\%)$ were represented in the rumen solid clone set; and the CFB group $(94.4\%)$ and LGCGPB $(5.6\%)$ were represented in the rumen epithelium clone set. These findings suggest that the rumen fluid, solid, and epithelium support different microbial populations that may play specific roles in rumen function.

Rehabilitation of severely worn dentition using Monolithic surveyed restoration and electronic surveying in RPD metal framework fabrication: A case report (심한 마모를 가진 환자에서 전자 서베잉을 이용한 금관 및 국소의치 수복 증례)

  • Choi, Youngha;Kim, Hyeong-Seob;Kwon, Kung-Rock;Pae, Ahran;Noh, Kwantae;Paek, Janghyun;Hong, Seoungjin
    • The Journal of Korean Academy of Prosthodontics
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    • v.56 no.3
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    • pp.243-249
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    • 2018
  • Excessive tooth wear results in unacceptable damage to the occlusal surface and can cause pulpitis, occlusal disharmony, dysfunction, and unesthetic result. Patients with severe attrition have to be classified as several types relative to the vertical dimension of occlusion (VDO) and the interocclusal distance for the prosthetic space. The patient in this case was a 80 - year - old woman who lost support of posterior occlusion and collapsed of the occlusal plane due to confrontation of the opposing teeth, accompanied by an increase in the number of remaining bristles, resulting in a loss of intermaxillary space for prosthesis. In this case, treatment with increased vertical dimension may have stability if the increase in vertical occlusal height is minimized within the required range, and a stable occlusal contact is provided after an increased vertical occlusal height stabilization period. After the new VDO had been confirmed under interim fixed restorations, definitive fixed restorations were produced. Through these treatment processes, we obtain satisfactory results that are functional and aesthetically pleasing.