• 대한치과의사협회지
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• 제49권9호
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• pp.520-526
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• 2011

Vascularized iliac crest flap include bone tissue of good quality and quantity for mandible segmental defect. Even if fibular flap can contain longer bone tissue, iliac crest has esthetic shape for mandible body reconstruction and large height for implant. Conventional vascularized iliac crest osteomyocutaneous flap is too bulky for reconstruction of intraoral soft tissue defect. But modified flap can reduce soft tissue volume, so is good for functional reconstruction of oral mucosa. It takes only one month for completely replace oral mucosa. The final mucosal texture is much better than other skin paddle flap, especially for implant prosthesis. Donor site morbidity of this method looks same level or less with other modalities functionally and socially. In case of oral mucosa-mandible combined defect, vascularized iliac crest with internal oblique muscle flap shows good outcomes for hard and soft tissue.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.3-10
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• 2005

In this study, 1-g shaking table tests on the model of CFR(Concrete-Face Rockfill) type "D" dam in operation and the model of virtual ECRD(Earth Core Rockfill Dam) of which static stability is about the same compared to the model of CFRD were carried out. The purpose of this study is to compare the seismic performance of CFRD and ECRD from the analysis of model test results. Displacement response behavior of the dam was examined through the measurement of vertical and horizontal displacement of model dam crest. Also, amplification characteristics of accelerometers installed with dam height were examined through the measurement of acceleration with dam height. Also, in the case of ECRD, patterns of excess pore pressure generation with dam height were examined. From the test results, it was found that accelerations of dam crest of CFRD and ECRD were amplified about 1.52 times and 2 times compared to the accelerations of dam bottom, respectively. amplification was outstanding at three quarters of dam height from the bottom of dam. This phenomenon was outstanding in case of ECRD. And it was estimated that vertical and horizontal displacement of prototype dam of CFRD were 6.8cm (0.1% of dam height) and 12.3cm (0.2% of dam height), respectively. Also, it was estimated that vertical and horizontal displacement of prototype dam of ECRD were 4.3cm (0.1% of dam height) and 5.5cm (0.11% of dam height), respectively.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.4137-4140
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• 2012

The authors present five cases of combined oral mucosa-mandible defects reconstructed with the vascularized internal oblique-iliac crest myoosseous free flap. This technique has many advantages compared to other conventional methods such as the radial flap, scapula flap, and fibula flap. Vascularized iliac crest flaps provide sufficient high-quality bone suitable for reconstructing segmental madibular defects. Although fibular flaps allow longer donor bone tissue to be harvested, the iliac crest can provide an esthetic shape for mandibular body reconstruction and also provides sufficient bone height for dental implants. Conventional vascularized iliac crest myoosseous flaps have excessive soft tissue bulk for reconstruction of intraoral soft tissue defects. The modification discussed in the present article can reduce soft tissue volume, resulting in better functional reconstruction of the oral mucosa. Another advantage is that complete replacement of the oral mucosa is observed in as early as one month post-operation. The final mucosal texture is much better than that obtained with other skin paddle flaps, which is especially beneficial for the placement of dental implant prostheses. Donor site morbidity looks to be similar to, if not less than that observed for other modalities in terms of function and esthetics. For combined oral mucosa-mandible defects, the vascularized internal oblique-iliac crest myoosseous free flap shows good results with respect to hard and soft tissue reconstruction.

• Structural Monitoring and Maintenance
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• 제2권1호
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• pp.49-64
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• 2015

This paper presents a method for assessing the risk of wave run-up and overtopping of existing coastal defences and for analysing the probability of failure of the structures under future hydraulic conditions. The recent UK climate projections are employed in the investigations of the influence of changing environments on the long-term performance of sea defences. In order to reduce the risk of wave run-up and overtopping caused by rising sea level and to maintain the present-day allowances for wave run-up height and overtopping discharge, the future necessary increase in crest level of existing structures is investigated. Various critical failure mechanisms are considered for reliability analysis, i.e., erosion of crest by wave overtopping, failure of seaside revetment, and internal erosions within earth sea dykes. The time-dependent reliability of sea dykes is analysed to give probability of failure with time. The results for an example earth dyke section show that the necessary increase in crest level is approximately double of sea level rise to maintain the current allowances. The probability of failure for various failure modes of the earth dyke has a significant increase with time under future hydraulic conditions.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.349-354
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• 2005

In this study, settlement characteristics of 23 CFRD was investigated from monitoring data and the method to estimate the crest settlements considering internal settlement during constructions was proposed. Moreover, crest settlement smaller than 20cm and deflection of face slab smaller than 20cm are not considered to be critical to the stability of large dam whose height is over 40m. Therefore, we assigned the region as safe zone that can be used as a guideline of maintenance of dam. These estimated data can be used in the design, construction and long-term maintenance in domestic CFRD hereafter.

• 한국해안·해양공학회논문집
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• 제23권6호
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• pp.414-421
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• 2011

경사입사파 내습시 직립구조물의 마루높이 산정을 위해 기존 연구의 대부분은 입사각에 따른 월파량 저감계수를 제시하였다. 그러나 기존 연구에서 파랑증폭과 월파의 공간적 분포는 고려하지 않았다. 본 연구에서는 직립구조물을 따른 파랑 증폭현상에 의한 월파의 공간적분포를 실험적으로 검토하였다. 실험결과에 의하면, 직립구조물 시점으로부터 유의파 파장 기준 3파장까지 구간은 직각입사와 동일한 방법으로 마루높이를 산정하고, 그 이후 구간에 대해서는 파랑의 증폭과 월파의 공간적 분포를 고려한 월파량 저감계수를 사용하는 것이 합리적인 것으로 검토되었다.

• 한국농공학회지
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• 제45권6호
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• pp.109-118
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• 2003

As a fundamental research to establish a safety operation plan for irrigation dams, this study presents hydrologic analysis conducted in Sungju Dam watershed based on various rainfall data. Especially those reservoirs without flood control feature are widely exposed to the risk of flooding, a safe and optimized operation program need to be improved against arbitrary flooding. In this study, reservoir routing program was developed and simulated for reservoir runoff estimation using WMS hydrology model. The model simulated the variations of reservoir elevation under the condition of open or closed emergency gate. In case of closed emergency gate, water surface elevation was given as 193.15 m, and this value exceeds the dam crest height by 1.65 m. When the emergency gate is open, the increment of water surface elevation is given as 192.01 m, and this value exceeds dam crest height by 0.57 m. As an alternative plan, dam height increase can be considered for flood control under the PMP (Probable Maximum Precipitation) condition. Since the dam size is relatively small compare to the watershed area, sound protection can be expected from the latter option rather than emergency gate installation.

• Journal of Periodontal and Implant Science
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• 제36권2호
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• pp.461-471
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• 2006

In order to achieve a satisfactory esthetic result of periodontal surgery or implant in maxillary anterior area, periodontists must be aware of normal alveolar bone anatomy. The purpose of this study was to evaluate the relationship of alveolar bone morphology to tooth shape and form. 78(mean age : 25 yrs) periodontally healthy volunteers participated in this study. Two maxillary central incisor and one lateral incisor were selected to study. With minimal local anesthesia, gutta-percha cone inserted to labial gingival sulcus of selected teeth just after bone sounding with periodontal probe. Metal ball (4mm diameter) attached to palatal fossa of central incisor. Then, periapical radiograph was taken according to long cone paralleling technique. After film scan, labial alveolar bone profile reproduced along interproximal bone and apical ends of gutta-percha cones on computer screen. By utilizing computer program, the distance from height of interproximal bone to the labial bone crest in central incisor-central incisor and central incisor-lateral incisor area was measured and converted to real distance by using vertical length of metal ball on film. After measuring crown length & width of central incisor, the 10 individuals ranked lowest GW/L ratio (crown width/length ratio) and the 10 ranked highest were selected as having a long-narrow(group N), or a short-wide(group W) form of the central incisors. Means of the distance from height of interproximal bone to the labial bone crest of group N, W were calculated and compared by means of independent t-test. The results were as follows: 1. Mean distance from the height of the interproximal bone to the labial bone crest was $3.5{\pm}0.7mm$ between two central incisor, and $2.8{\pm}0.6mm$ between central and lateral incisor. 2. Mean GW/L ratio of group N was 0.57, and group W was 0.8. Mean distance from the height of the interproximal bone to the labial bone crest of group N was higher than group W in both measured area(measurements of group N, W were $3.9{\pm0.2mm$ and $3.5{\pm}0.2mm$ between two central incisor, $3.0{\pm}0.2mm$ and $2.8{\pm}0.2mm$ between central and lateral incisor), but there were no statistically significant differences when the groups were compared. Within the limits of the present study, there was a tendency that subjects with long-narrow teeth have more scalloped alveolar bone profile than subjects with short-wide teeth in upper anterior area, but no statistically significant differences were found.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.312-315
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• 2002

This paper summarizes the results of a numerical study conducted to analyze the effect of selected process parameters on material flow and thread profile in thread rolling of large diameter blanks. Based on the previous work where a plane strain mode was found to provide a reasonable approximation of the thread rolling process, the effect of varying thread form, friction factor, flow stress, and blank diameter on effective strain and thread height was analyzed using the finite element code DEFORM. This study show that effective strain for flank angle, that blank diameter had important effect on the as-rolled thread while flow stress, friction factor, and crest round of dies had significant impact on effective strain at the thread root and crest and load of thread rolling. While the rate of strain harding was found to have an effect on the crest profile, the results indicate that it is the primary factor responsible for seam formation in rolled threads.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1118-1125
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• 2005

In this study, seismic safety of CFRD(Concrete-Face Rockfill Dam) type "D" dam in operation is evaluated from the results of 1-g shaking table test using similitude laws. Model dam is made by similitude law considering the grain size of prototype dam component. After the model dam is impounded to the normal water level(N.W.L), it is excited by artificial earthquake wave corresponding to standard design respond spectrum of the "D" dam site. Displacement response behavior of the dam is examined through the measurement of vertical and horizontal displacement of dam crest. Also, amplification characteristics of acceleration with dam height is examined through the measurement of acceleration with dam height. Finally, the purpose of this study is to evaluate seismic safety of "D" dam in operation. From the results of acceleration measurement, it was found that acceleration of dam crest was amplified about 1.52 times compared to the acceleration of dam bottom and amplification phenomenon is outstanding at three quarters of dam height from the bottom of dam. From the analysis of displacement behavior, it was estimated that vertical displacement of prototype dam is 6.8cm (0.1% of dam height) and horizontal displacement 12.3cm(0.2% of dam height). These percentages is much lower than 1% of dam height(general stability criteria). Therefore, it was concluded that seismic stability of "D" dam against an estimated earthquake is guaranteed.