• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.802-810
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• 2003

In this paper, the modified singular fracture process zone (S-FPZ) model is proposed to consider variation of a fracture criterion for continuous crack propagation in concrete. The fracture properties of the proposed fracture model are strain energy release rate at a micro-crack tip and crack closure stress (CCS) versus crack opening displacement (COD) relationship in the FPZ. The proposed model can simulate the estimated fracture energy of experimental results. The analysis results of the experimental data shows that specimen geometry and loading condition did not affect the CCS-COD relation. But the strain energy release rate is a function of not only specimen geometry but also crack extension. Until 25 mm crack extension, the strain energy release rate is a constant minimum value, and then it increased linearly to the maximum value. The maximum fracture criterion occurred at the peak load for an large size specimen. The fracture criterion remains the maximum value after the peak load. The variation of the fracture criterion is caused by micro-cracking and micro-crack localizing. The fracture criterion of strain energy release rate can simply be the size effect of concrete fracture, and it can be used to quantify the micro-tracking and micro-crack localizing behaviors of concrete.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.81-136
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• 1988

The aim of this study was to determine whether T.M.J. tomographic examination yielded significant differences in condyle positions among asymptomatic, myalgia, derangement, and arthrosis groups of T.M.J. disorders. The author obtained sagittal linear tomograms of right and left T.M.Js. of 36 asymptomatic, 22 myalgia, 54 derangement, and 31 arthrosis patients taken at serial lateral, central, and medial sections in the intercuspal position after submentovertex radiographs analyzed. With the dual linear measurements of the posterior and anterior interarticular space, condyle positions were mathematically expressed as proportion. All data from these analysis was recorded and processed statistically. The results were obtained as follows. 1. In asymptomatic group, radiographically concentric condyle position was found in 50.0% to 65.4% of subjects, with a substantial range of variability. No significant differences existed between men and women and also between right and left T.M.Js. for condyle position. 2. In women, significant difference for mean condyle position of left lateral section of each diagnostic category existed between derangement and myalgia groups (P<.05). Also that of left central section existed between derangement and myalgia groups, and that of left medial section existed between derangement and myalgia groups (P<.05). 3. In main-symptom side, condyle position in myalgia group was more concentric, and condyle position in derangement group was more posterior. This showed significant differences between derangement and myalgia groups in lateral, central, and medial sections of main- symptom sides, and only between derangement and myalgia groups in central section of contra-lateral sides (P<.05). Condyle position in arthrosis group was broadly distributed among all positions. 4. In contra-lateral side, significant difference for mean condyle position of central section of each symptomatic group existed between derangement and myalgia groups (P<.05). Condyle position in derangement group was more posterior. The distribution of the condyle position of contra-lateral side in patients with unilateral symptoms was similar to that of main-symptom side in each symptomatic group. No significant difference existed between main-symptom and contra-lateral sides. 5. For internal derangement subgroups, condyle position in reducible disc displacement group was more posterior than non-reciprocal and locking groups, but there was no significant difference. 6. From 16 to 25 years, significant difference for mean condyle position of medial section of main-symptom side of each symptomatic group existed between myalgia and derangement groups (P<.05).

• Archives of Plastic Surgery
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• v.47 no.6
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• pp.574-582
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• 2020

Background Several oncoplastic approaches have been implemented in recent years to enhance cosmetic results and to reduce complications. The round block technique is a volume displacement technique for breast reconstruction after breast-conserving surgery (BCS). However, its indications are currently limited according to tumor location, and its cosmetic results and complications have not been clearly established. We hypothesized that the round block technique could produce favorable cosmetic results without major complications regardless of tumor location or nipple-tumor distance, below a certain resected tumor volume and tumor-breast volume ratio. Methods All breast reconstructions using the round block technique after BCS were included in this analysis. Patients' data were reviewed retrospectively to investigate complications during follow-up, and clinical photos were used to evaluate cosmetic results. The relationships of tumor location, nipple-tumor distance, tumor volume, and the tumor-breast volume ratio with cosmetic results were investigated. Results In total, 108 breasts were reconstructed. The mean resected tumor volume was 30.2±15.0 mL. The cosmetic score was 4.5±0.6 out of 5. Tumor location, nipple-tumor distance, tumor volume, tumor-breast volume ratio, radiotherapy, and chemotherapy had no significant effects on cosmetic results or complications. There were no major complications requiring reoperation. Conclusions Breast reconstruction using the round block technique after BCS can lead to good cosmetic results without major complications regardless of the tumor location, nippletumor distance, radiotherapy, or chemotherapy. Below the maximum tumor volume (79.2 mL) and the maximum tumor-breast volume ratio (14%), favorable results were consistently obtained.

• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.377-386
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• 2006

There is an inseparable relation between human race and engineering work. As world developed into highly industrialized society, a diversity of large structures is being built up correspondently to limited topographical circumstance. Though large structures are national establishments which provide us with convenience of life, there are some disastrous possibilities which were never predicted such as ground subsidence and degradation. It is very difficult to analyze the volume of total metamorphosis with the relative displacement measurement system which is now used and it is impossible to know whether there is structural metamorphosis within a permissible range of design or not. In this research with an object of 13-year-old earthen dam, through generating point-cloud which has 3D spatial coordinates(x, y, z) of this dam by means of 3D Laser Scanning, we can get real configuration data of slanting surface of this dam with this method of getting a number of 3D spatial coordinates(x, y, z). It gives 3D spatial model to us and we can get various information of this dam such as the distance of slanting surface of dam, dimensions and cubic volume. It can be made full use of as important source material of reinforcement and maintenance works to detect previously the bulging of the dam through this research.

• Journal of the Korean Geophysical Society
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• v.3 no.1
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• pp.1-12
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• 2000

A palaeomagnetic study was carried out on Early through Late Cretaceous sandstones and volcanic sequences (the Songnaedong Formation, Chaeyaksan Volcanics, Konchonri Formation, and Jusasan Andesite it ascending order) from Konchonri area in the northern Milyang subbasin of the Kyongsang Basin, Korea. A high-temperature stable remanence with direction of $d=22.9^{\circ},\;i=59.1^{\circ}\;({\alpha}_{95}=3.0^{\circ})$ has been isolated and a corresponding pole was $71.6^{\circ}N,\;199.6^{\circ}E\;(A_{95}=4.2^{\circ})$. The characteristic high-temperature component resides in both hematite and magnetite. The primary nature of this remanence is confirmed from positive fold and reversals tests, The palaeopole is consistent with those of the Hayang Group in other parts of the Kyongsang Basin. A comparison of the palaeomagnetic pole position from the studied area with the contemporary pole from China west of the Tan-Lu fault presents that Konchonri area has experienced little latitudinal displacement nor vertical-axis block rotation relative to the Chinese blocks since the Cretaceous. Based on the formations indicating dual polarity, radiometric and paleontologic data, the magnetostratigraphic age of the studied sequence from the Songnedong Formation to the Jusasan Andesite ranges from upper Albian to lower Campanian reverse polarity chronozone. On the other hand, volcanic samples of the Chaeyaksan Volcanics and the Jusasan Andesite showed the scattered directions considered in group, even though individual sample showed a stable remanent magnetization in response to thermal demagnetization. It indicates that they have been reworked after acquisition of the stable remanent magnetization.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.3
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• pp.369-378
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• 2015

Various forms of wearable bio-signal monitoring systems have been developed recently. Acquisition of stable bio-signal data for health care purposes needs to be unconscious and continuous without hindrance to the users' daily activities. The garment type is a suitable form of a wearable bio-signal monitoring system; however, motion artifacts caused by body movement degrade the signal quality during the measurement of bio-signals. It is crucial to stabilize the electrode position to reduce motion artifacts generated when in motion. The problems with motion artifacts remain unresolved despite their significant effect on bio-signal monitoring. This research creates a foundation for the design of garment-type wearable systems for everyday use by finding a method to reduce motion artifacts through modular design. Two distinct garment-type wearable systems (tee-shirt with a motion artifact-reducing module (MARM) and tee-shirt without a MARM) were designed to compare the effects of modular design on the measurement of heart activity in terms of electrode position displacement, signal quality index value, and morphological quality. The tee-shirt with MARM showed superior properties and yielded higher quality signals than the tee-shirt without MARM. In addition, the tee-shirt with MARM showed a better repeatability of the heart activity signals. Therefore, a garment design with MARM is an efficient way to acquire stable bio-signals while in motion.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.425-431
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• 2015

Measurement accuracy was evaluated for the respiratory air flow transducer developed for applications under emergent situations. Pressure-Flow calibration equation was obtained by acquisition of air flow signals from the transducer in response to 6 flow waveforms, similar to those of artificial ventilation, generated by the standard flow generator system. Tidal volume and maximal flow rate were calculated on the flow signal then compared with the error-free data obtained by the linear displacement transducer of the flow generator system. Mean relative error of the tidal volume was within 3% and that of the maximal flow rate, approximately 5%, demonstrating accurate enough measurements. Therefore, the transducer could be applied to emergent situations to monitor the respiratory air flow signal as well as diagnostic parameters in real time.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.335-342
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• 2015

Objective : The purposes of this study was to analyze the effects of the stirrup length fitted to the rider's lower limb length and it's impact on less skilled riders during trot in equestrian events. Methods : Participants selected as subjects consisted of less skilled riders(n=5, mean age: $40.02{\pm}10.75yrs$, mean heights: $169.77{\pm}2.08cm$, mean body weights: $67.65{\pm}7.76kg$, lower limb lengths: $97.26{\pm}2.35cm$, mean horse heights: $164.00{\pm}5.74cm$ with 2 type of stirrups lengths(lower limb ratio 74.04%, and 79.18%) during trot. The variables analyzed consisted of the displacement for Y axis and Z axis(head, and center of mass[COM]) with asymmetric index, trunk front-rear angle(consistency index), lower limb joint(Right hip, knee, and ankle), and average vertical forces of horse rider during 1 stride in trot. The 4 camcorder(HDR-HC7/HDV 1080i, Spony Corp, Japan) was used to capture horse riding motion at a rate of 60 frames/sec. Raw data was collected from Kwon3D XP motion analysis package ver 4.0 program(Visol, Korea) during trot. Results : The movements and asymmetric index didn't show significant difference at head and COM, Also, 74.04% stirrups lengths in trunk tilting angle showed significant difference with higher consistency than that of 79.18% stirrups lengths. Hip and knee joint angle showed significant difference with more extended posture than that of 74.04% stirrups lengths during trot. Ankle angle of 79.18% stirrups length showed more plantarflexion than that of 74.04% stirrups lengths. Average vertical force of rider showed significant difference with higher force at 79.18% stirrups lengths than that of 74.04% stirrups lengths during stance phase. Conclusion : When considering the above, 74.04% stirrups length could be effective in impulse reduction with consistent posture in rather less skilled horse riders.

• Archives of Craniofacial Surgery
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• v.21 no.5
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• pp.276-282
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• 2020

Background: Orbital fractures are the most common pediatric facial fractures. Treatment is conservative due to the anatomical differences that make children more resilient to severe displacement or orbital volume change than adults. Although rarely, extensive fractures may result in enophthalmos, causing cosmetic problems. We aimed to establish criteria for extensive fractures that may result in enophthalmos. Methods: We retrospectively reviewed the charts of patients aged 0-15 years diagnosed with orbital fractures in our hospital from January 2010 to February 2019. Computed tomography images were used to classify the fractures into linear, trapdoor, and open-door types, and to estimate the defect size. Data on enophthalmos severity (Hertel exophthalmometry results) and fracture pattern and size at the time of injury were obtained from patients who did not undergo surgery during the follow-up and were used to identify the surgical indications for pediatric orbital fractures. Results: A total of 305 pediatric patients with pure orbital fractures were included-257 males (84.3%), 48 females (15.7%); mean age, 12.01±2.99 years. The defect size (p=0.002) and fracture type (p=0.017) were identified as the variables affecting the enophthalmometric difference between the eyes of non-operated patients. In the linear regression analysis, the variable affecting the fracture size was open-door type fracture (p<0.001). Pearson's correlation analysis demonstrated a positive correlation between the enophthalmometric difference and the bony defect size (p=0.003). Using receiver operating characteristic curve analysis, a cutoff value of 1.81 ㎠ was obtained (sensitivity, 0.543; specificity, 0.724; p=0.002). Conclusion: The incidence of enophthalmos in pediatric pure orbital fractures was found to increase with fracture size, with an even higher incidence when open-door type fracture was a cofactor. In clinical settings, pediatric orbital fractures larger than 1.81 ㎠ may be considered as extensive fractures that can result in enophthalmos and consequent cosmetic problems.

• Geotechnical Engineering
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• v.14 no.5
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• pp.129-142
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• 1998

This research is focused on the inducement of the constitutive equation considering the creep strain component and on the development of a finite element method program. The purpose of this research was to contribute to the design of construction structures or to the construction management in soft clay ground through predicting the long-term strain of construction structures reasonably bused on the above program. Modified Cam Clay model was adopted to describe the elastic-plastic behavior of clayey soil. And in the calculation of the creep sprain, the secondary coefficient of consolidation C. was applied for considering the volumetric creep element and the constants m, $\alpha$, A were rosed by the empirical creep equation proposed by Singh 8E Mitchell for considering the deviatoric creep element. To examine the reliability of the program which is developed in this study, the estimated values by this program were compared with the theoretical solution and the experimental results. And the applicability of the developed program was found to be reliable from the sensitive analysis of each parameters used in this study. According to the results obtained from the application of the program on the field measurement data, the estimated values by the program were found with be consistent with the actual values. And from the analysis of the displacement of embankments, the case of considering the creep behavior induced much fower errors than the case of neglecting it. But the results obtained from considering the volumetric creep behavior only were slightly underestimated the results from considering the deviator creep behavior showed the slightly overestimated values. Therefore, it remains the task of further studios to develop the laboratory test devices to obtain the reliable creep parameters, and to select the appropriate soil parameters, etc.