• Journal of the Korean Geotechnical Society
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• v.27 no.10
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• pp.25-33
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• 2011

Suction buckets have been widely used for offshore structures such as anchors for floating facilities, and the foundations of offshore wind energy turbines. However, the design guidelines for suction buckets have not been clearly suggested. Therefore, this study performed the numerical analysis by using ABAQUS (2010) to evaluate bearing capacities and load-movement behaviors of the suction bucket in NC clay. For the numerical analysis, the depth ratio L/D (L=embedded length of skirt; D=diameter of a bucket) was varied from 0.25 to 1.0. The analysis results showed that the L/D ratio has a significant effect on the bearing capacity, and the vertical and horizontal capacities respectively increased by about 40% and 90%, when L/D ratio increased from 0.25 to 1.0. At the vertical loading, the bucket showed the similar failure mode with a deep foundation, so the shaft and toe resistances can be separately evaluated. At the horizontal loading, the bucket with L/D=O.25 showed the sliding failure mode and the bucket with $L/D{\geq}0.5$ showed the rotational failure mode.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.4
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• pp.1-8
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• 1985

Stability analysis of the embankment as to water level varation is the most important problem in the safety of the slope because the stress of embankment inside varies as to drawdown of seepage line. Especially when the water level is rapidly drawdown, because the flow direction of the free surface changes the toe of embankment, the factor of safety comes to small, therefore the embankment is dangered. For the purpose of studing these phenomena, the experimental models are built with sand in the laboratory. In the experimental consideration, the falling seepage line and the shape of failure are measured. This paper intends to study the failure slip surface, the relationship between the factor of safety and drawdown velocity, and hydraulic gradient. The results of the experimental study are summarized as follows; 1. Owing to the drawdown of free surface, sliding failure occurred in the upstream fill, the height of failure is 5~10, 9~15, and 13~21(cm) in each model. 2. In consideration of the distribution of pore water pressure Table-5 shows each factor of safety. In the relationship between the drawdown velocity and the factor of factor it's velocity should be limited to 0.21~0.28 (cm/sec), according to each models. In the relationship between the factor of safety and the hydraulic gradient within the upstream slope, it's gradient must be below 0.36~0.43.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.107-115
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• 2008

The purpose of this study was to investigate muscle activity and vertical ground reaction force(F) in children with Down syndrome(DS) during vertical jump. Six DS and one healthy child performed vertical jump. Four muscles(Biceps femoris, Rectus femoris, Tibialis anterior & Gastrocnemius) and F were analyzed. Gastrocnemius in DS showed lower muscle activity in a propulsive phase. Impulse during 0.3sec before toe-off in DS displayed lower value than that in the healthy child. The second peak of F in DS occurred later than that in the healthy child, so DS performed landing with their knee more flexed. The first and second peak of F and loading rate to the second peak of F in DS showed lower value than those in the healthy child. Therefore, DS might have lower ability to absorb the force while landing from a vertical jump.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.1-9
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• 2008

The purpose of this study was to investigate the effect of different obstacle heights on the plantar foot pressure during obstacle crossing. Sixteen healthy adults who had no musculoskeletal disorders were instructed to perform unobstructed level walking and to step over obstacles corto 10cm, 20cm, 30cm. Plantar foot forces and pressures were recorded by the Footmat system(Tekscan, Boston, USA) during level and obstacle walking with barefoot. Plantar foot surface was defined as seven regions for pressure measurement; two toe regions, three forefoot regions, one midfoot region, one heel region. One-way ANOVA was used to compare each region data of foot according to various heights. The results indicated that there are significant differences on peak pressure and maximal forces regarding each region at stance phase. As height of obstacle became high, the pathway of COP had a tendency to be short and abducted. Plantar pressure of foot could be changed by obstacle height and these findings demonstrated that obstacle with different height have an effect on structure and function of the foot.

• Radiation Oncology Journal
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• v.10 no.1
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• pp.107-113
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• 1992

Increasing frequency of skin cancer, mycosis fungoides, Kaposi's sarcoma etc, it need to treatment dose planning for total skin electron beam (TSEB) therapy. Appropriate treatment planning for TSEB therapy is needed to give homogeneous dose distribution throughout the entire skin surface. The energy of 6 MeV electron from the 18 MeV medical linear accelerator was adapted for superficial total skin electron beam therapy. The energy of the electron beam was reduced to 4.2 MeV by a $0.5\;cm\times90\;cm{\times}180\;cm$ acryl screen placed in a feet front of the patient. Six dual field beam was adapted for total skin irradiation to encompass the entire body surface from head to toe simultaneously. The patients were treated behind the acryl screen plate acted as a beam scatterer and contained a parallel-plate shallow ion chamber for dosimetry and beam monitoring. During treatment, the patient was placed in six different positions due to be homogeneous dose distribution for whole skin around the body. One treatment session delivered 400 cGy to the entire skin surface and patients were treated twice a week for eight consecutive weeks, which is equivalent to TDF value 57. instrumentation and techniques developed in determining the depth dose, dose distribution and bremsstrahlung dose are discussed.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.259-264
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• 2002

In this study, sintering properties of Artificial Lightweight aggregates(ALAs) prepared from coal ash as a function of sintering temperature (900$^{\circ}$C, 1000$^{\circ}$C, 1100$^{\circ}$C) and time (2min, 5min, 10min) when limestone added as lightweight mineral was investigated. Increasing the sintering temperature resulted simultaneously from a decline of quartz mineral as well as growth of mullite mineral. Addition of limestone to ALAs newly formed sintered minerals such as clinoptilolite and plagioclase. Sintering effect of ALAs prepared from coal ash and limestone was more affected by a sintering temperature than time. As sintering temperature and time increae, transition of macropore to micropore and formation of closed pores were happened, consequently shrank the total pore volume of ALAs. The surface of ALAs sintered at 1000$^{\circ}$C for 5min was nearly not detected open pores due toe amalgamation effect of molten slag layer but homogeneous distributions of closed pores with micro-scale were examined in cross sectional area ALAs. Sintering temperature and time which present the most adequate state, in the preparation of ALAs, are corresponded to 1000$^{\circ}$C and 5min, respectively.

• Journal of Korean Foot and Ankle Society
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• v.9 no.2
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• pp.173-178
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• 2005

Propose: There have been many debates about the ideal surgical technique for acute Achilles tendon rupture. The purpose of this study is to review and analyze the clinical outcome of the acute Achilles tendon ruptures that had been repaired by indirect suture technique with minimal incision that utilized an instrument called Achillon (Newdeal, France). Materials and Methods: This study is based on the 14 cases (14 patients) of acute Achilles tendon total ruptures that have been repaired by minimal incision technique utilizing Achillon instrument from June 2003 to December 2004. Two cases were reruptured before 8 weeks and repaired again using Krackow suture which left 12 feet for postoperative functional evaluation with at least 6 months of follow-up. Ten cases were men and average age at time of injury was 34.4 (26-49) years. The time from injury to surgery was an average of 4.5 (1-9) days and the postoperative evaluations were done by an Arner-Lindholm scale and AOFAS score. The ability to return to original work and sports activities as well as patient satisfaction were also evaluated. Results: The follow-up period was averaged for 13.2 (6-24) months. Seventy-one percent of cases were ruptured during sports activities. The ruptured level was the average of 5.1 cm (3.2-8 cm) above calcaneal attachment and the skin incision was averaged for 2.7 cm (2.5-3.0 cm) long. At final follow-up, standing on tip-toe was possible in all cases while the heel-floor height on ruptured side was shorter by 0.7 cm (0-2 cm). By Arner-Lindholm evaluation scale, 9 cases were excellent, and 3 cases were good. Overall AOFAS score was an average of 96.1 (94-100), and all patients were satisfied with the result. Patients returned to work at an average of 1.3 months after the surgery and pre-injury sports activities were all possible from at 6 months after operation. Conclusion: Since we have treated acute Achilles tendon ruptures with minimal incision technique utilizing the Achillon and gained encouraging functional results with all patients returning to previous work with high patient satisfaction, this technique could be recommended as one of the ideal surgical options for the Achilles tendon ruptures.

• Journal of Korean Foot and Ankle Society
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• v.11 no.1
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• pp.23-27
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• 2007

Purpose: Scarf osteotomy can provide the simultaneous correction of the hallux valgus angle (HVA), 1-2 intermetatarsal angle ($IMA_{1-2}$), DMAA and the plantar displacement of the fragment. The study was conducted to understand the multi-dimensional correction of the hallux valgus. Materials and Methods: Fourty eight patients who had undergone Scarf osteotomy with hallux valgus at more than $30^{\circ}$ of HVA and more than $15^{\circ}$ of $IMA_{1-2}$ were studied. Before an osteotomy, a reference K-wire was inserted to the 1st metatarsal head. After the osteotomy, the plantar fragment was moved laterally and the proximal end of the fragment was forced beyond the distal end which resulted in an internal rotation of the head fragment to correct the DMAA. Results: The HVA improved an average of $33.3^{\circ}$ to $7.7^{\circ}$ with the IMA1-2 respectively from $15.4^{\circ}$ to $6.5^{\circ}$. The DMAA improved an average of $19.5^{\circ}$ ($5.2-30.9^{\circ}$) to $4.5^{\circ}$ ($0.4-13.8^{\circ}$). By checking the angle, which was at an average of $25^{\circ}$ between the plantar surface of the foot and the osteotomy plane, the average distance of 1.9 mm (1.18-3.1 mm) of plantar displacement was measured using the value of sine (sin 25 = 0.422). Conclusions: It is possible to correct the HVA, IMA1-2 and DMAA simultaneously with one osteotomy making the lateral shift, the internal rotation and the plantar displacement of the plantar head fragment as desired. Despite the technicality and difficulty of the Scarf osteotomy, once familiarized through myriad procedures, all disadvantages are outweighed by the success and satisfaction of both patient and surgeon.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.2 no.1
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• pp.132-177
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• 1974

Toe public library may perform a social good only when its objectives are adequate to the community's needs. The present purpose of the public library in the Korean Library Act has no direct concern for our social needs from its very beginning because it was not created in response to our social needs but transplanted from American principles. It is, therefore. difficult to expect socially useful output of our public library programs under the present purpose which may be inadequate to our social tradition and needs. This study purposes to examine validity of the present purpose of the public library in the Korean Library Act, in the light of our community needs and our own library tradition. The methods employed to achieve the purpose of the study are (1) to survey needs of the library frequenters through questionnaire, and interviews with the public librarians in Seoul, (2) to gather the statistical data relevant to, and supporting, the hypothesis, and (3) to compare our social background with that of the United States of which the American purpose, a model for our present purpose, came out. The conclusion is as follows: A. The idea to induce people to pull themselves upward by providing for all the members of the community access to the world's best books shelved in the public library should be abandoned. The reasons are (1) that the idea is alien in our public library tradition, (2) that little demand of the community goes with the idea, and (3) that reading outside the library has come into wide practice, thanks to recent increase in individual income and that in publications. B. That the public library maintains fiction and other recreational reading materials is meaningless in the light of the community needs. These are the two explanations supporting the thesis. (1) The "uplift" theory has proved inoperative and people apparently do not progress from, light fiction to more respectable fare. (2) The conviction that fiction and other recreational reading materials keep the middling classes from the "vicious" entertainments maintaining order in the community by giving them a harmless source of recreation has lost its significance as the modern society provides a number of choices in recreation: television is an obvious example. C. The nature of the informational needs of the community has radically changed, so radically as to require substantial changes in the outlook, collections, and services of the public library, which is :slow in adopting itself to the new social surroundings in Korea. D. 92.2 per Cent of the present frequenters of the public library are high school and college students. Since the library is to meet the existing community needs it should turn its attention to the student group, and develop the means to serve it better, not the "theoretical group of specialists who do not come to "the public library. E. In revision of the purpose of the public library, priority of each objective should be given. The priorities in the last analysis are research and information. culture, recreation in that order.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.541-552
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• 2019

In this study, landslide flume tests were performed to analyze characteristics of ground characteristics and landslide occurrence due to rainfall infiltration. As test materials, weathered granite soil and gneiss soil, the most frequent landslides in Korea, were used, and landslides were triggered by heavy rain (Intensity = 200 mm/hr). The measurement sensors were installed with 3 sets at toe, slope, top part and shallow (GL-0.2 m), middle (GL-0.4 m), and deep (GL-0.6 m) depth in the slope and measured at 10 second intervals. After landslide flume tests, the slope stability analysis was performed by applying the unsaturated soil theory based on the change of ground characteristics and compared with actual landslide occurrence from flume test. As a result of the analysis, factor of safety reflected the landslide occurrence from flume test and factor of safety decreased as rainfall infiltration, leading to slope failure. Finally we compared to the factor of safety below 1 and actual landslide occurrence time, the average difference was 1,600 seconds for weathered granite soil and 5,400 seconds for weathered gneiss soil.