• Journal of Korean Society of Steel Construction
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• v.13 no.3
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• pp.289-299
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• 2001

The purpose of this study was to analyze the characteristics of semi-igid behavior of the steel tubular column to H-beam connection reinforced with exterior square-plate diaphragms and to check the main parameters that affect this behavior. Steel tube connections without interior diaphragm and/or complicated exterior diaphragm show the considerable flexibility due to out of-plane deformation of tube flange. For the exact analysis well-reflected the effect of this flexibility on the overall frame performance. it need to find out the moment-rotation curve function that well trace the result of experiment in the whole region and the function should be simply transformed into an adequate form for the nonlinear analysis program. After collecting several test data same to the connection type considered. we carried out FEM analysis using ANSYS for the assumed beam-to-column connection developed from the simple tension test and the results are compared with experimental values. Based on the parametric study. we proposed the moment-relation curve function and performed the multiple-regression analysis procedure for three parameters consisting of this function with the main geometric parameter of this connection type.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.687-694
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• 2005

In current design practice, the thickness of the floor slab has been determined to satisfy requirement for deflection control. However, previous study shows that the floor thicknesses in residential buildings may not satisfy the floor vibration criteria, even though the thickness is determined by the serviceability requirements in current design provisons. Thus it is necessary to develop the procedure to determine slab thickness that satisfies the floor vibration criteria. This study attempts to propose slab thickness for flat plate slab systems that satisfies floor vibration criteria against occupant induced floor vibration(heel drop load). Two boundary conditions(simple and fixed support), three square flat plates(4, 6, 8m), and five concrete strength($18\~30$ MPa) are considered. Since there are large uncertainties in loading and material properties, probabilistic approach is adopted using Monte-Carlo simulation procedures.

• Journal of Korean Neurosurgical Society
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• v.46 no.5
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• pp.425-430
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• 2009

Objective : The present study analyzed the risk factors, prevalence and clinical results following revision surgery for adjacent segment degeneration (ASD) in patients who had undergone lumbar fusion. Methods : Over an 8-year period, we performed posterior lumbar fusion in 81 patients. Patients were followed a minimum of 2 years (mean 5.5 years). During that time, 9 patients required revision surgery due to ASD development. Four patients underwent autogenous posterolateral arthrodesis and extended transpedicle screw fixation, 4 patients underwent decompressive laminectomy and interspinous device implantation, and 1 patient underwent simple decompression. Results : Of the 9 of patients with clinical ASD, 33.3% (3 of 9) of patients did not have radiographic ASD on plain radiographs. Following revision surgery, the clinical results were excellent or good in 8 patients (88.9%). Age > 50 years at primary surgery was a significant risk factor for ASD development, while number of fusion levels, initial diagnosis and type of fusion were not. Conclusion : The incidence of ASD development after lumbar surgery was 11.1% (9 of 81) in this study. Age greater than 50 was the statistically significant risk factor for ASD development. Similar successful clinical outcomes were observed after extended fusion with wide decompression or after interspinous device implantation. Given the latter procedure is less invasive, the findings suggest it may be considered a treatment alternative in selected cases but it needs further study.

• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.3
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• pp.96-110
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• 2008

Differing from civil engineering and construction, landscape architecture projects are far from efforts in operation and project management. Under the circumstances, it is worthwhile to adopt scope definition from project management for construction and civil engineering in some respects. First, scope definition is able to be conducted through a simple procedure without additional investment in capital and time. Second, the output produced by scope definition is very substantial. The research scrutinized scope definition procedures accompanied by landscape architecture project execution and derived various methods in order to help scope definition for efficient landscape architecture projects. Based on the literature review, a design case study, and an exert interview, the project success elements were developed consisting of 3 sections, 8 categories and 50 elements, grounded on the theoretical base of PDRI. The elements are expected to pave a way to an adequate level of scope definition among participants of landscape architecture projects and contribute in efficient project execution.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.574-580
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• 2008

Purpose: Philtral deformity is a stigma of secondary cleft lip nose. It occurs from the false arrangement of orbicularis oris muscle and the scar of previous operation. Various methods have been used to correct this deformity. We successfully corrected philtral deformity using overlapping of orbicularis oris muscle flap. Methods: From November 2000 to August 2007, we performed 39 cases of correction of philtral deformity in secondary cleft lip nose with overlapping of orbicularis oris muscle flap. Their age ranged from 5 to 53 years old. Existing scar tissue of previous operation was deepithelialized and preserved as scar flap. Lateral orbicularis oris muscle flap was elevated, advanced and overlapped upon medial muscle flap after dissection of orbicularis oris muscle of both sides. Reconstruction of philtral column was made from overlapping area by fixation of end part of lateral muscle flap to the point between philtral dimple and column. The degree of muscle flap advancement was decided by correction state of lateral muscle bulging. Correction of nostril floor depression or whistle deformity was also performed with preserved scar flap, if necessary. Results: Realignments of orbicularis oris muscle were possible in the majority of the patients and final results of philtral reconstruction were satisfactory mostly. Correction of nostril floor depression and whistle deformity was also achieved. Additional correction was performed later to 4 patients in whom insufficient reconstruction was noted. No significant complication was observed. Conclusion: More natural and symmetric philtrum was acquired with overlapping of orbicularis oris muscle flap. To the authors' knowledge, it is an easy and effective method for correction of philtral deformity through anatomical rearrangement of distorted orbicularis oris muscle with relatively simple procedure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.1
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• pp.48-55
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• 2001

The purpose of this study was to evaluate the analytical accuracy and precision of microwave oven digestion/atomi absorption spectrophotometry (AAS) for analyzing airborne chromium collected on mixed cellulose ester membrane (M filter from the work environment, and to compare the accuracy and the precision with those of the National Institute for Occupational Safety and Health (NIOSH) Method #7024 hot plate digestion/AAS method. For this study, field air sample pairs were collected from a electroplating process, and spiked samples in a laboratory were prepared and using these samples. Two digestion methods were comp; and evaluated in terms of recovery rate and bias as indices of accuracy and coefficient of variation as a index of precision. The results and conclusions are as follows. In spiked samples, the accuracies (% mean recoveries) of hot plate/AAS and microwave oven/AAS method were 97.19%, 97.1%, respectively, and the precisions (pooled respectively, and the precisions (pooled coefficient of variance, $CV_{pooled}$) 6.93% and 3.88%, respectively. The biases of hot plate ani microwave oven methods were 4.56 - 14.7% and 2.22 - 7.42% respectively. There was no statistically significant difference between hot plate and microwave oven methods recovery rates of spiked samples (p>0,05). Also, no statistically significant difference was shown among the concentrations of air samples determined by two method (p>0.05). In conclusion, microwave oven/AAS method h excellent accuracy and precision, and advantages such as time-saving and simple procedure in comparison with the classical NIOSH method. Therefore, this method can be use widely to analyze airborne chromium collected on MCE filter from the work environments.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.626-629
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• 2008

Purpose: We investigate the possibility of vessel preservation with glycerol and evaluate the potential of preserved gastroepiploic artery as a tool for the microsurgical practice. Methods: In 5 early gastric cancer patients, IRB(No. C-0603-040-170), we gained gastroepiploic artery specimens(5 segments, about 10 cm) after gastrectomy. Each segment was rinsed in a normal saline and subsequently placed in a bottle, containing 50 mL anhydrous glycerol (87%). The bottles were refrigerated at $4^{\circ}C$, the longest preservation time being 5 months. Results: At first glance, no fragmentation was detected and the surface of vessel seemed mild sclerotic. In histological examination, vascular structures remained intact though preservation with glycerol led to a mild atrophy of the smooth muscle in the tunica media. Especially, we found out the elastic fibers and endothelial lining of the intima were preserved until 5 months. Adequate status for using microsurgical practice was also maintained and leakage test was performed successfully with gentian violet ink. Conclusion: Based on the results obtained in this study, the gastroepiploic artery preservation with glycerol as a training model for microvascular anastomosis is a technically very simple procedure and useful for the novice microsurgeon.

• Journal of Mechanical Science and Technology
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• v.16 no.10
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• pp.1222-1228
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• 2002

This research is the development of a flexible tactile sensor array for service robots using PVDF (polyvinylidene fluoride) film for the detection of a contact state in real time. The prototype of the tactile sensor which has 8${\times}$8 array using PVDF film was fabricated. In the fabrication procedure, the electrode patterns and the common electrode of the thin conductive tape were attached to both sides of the 281$\mu\textrm{m}$ thickness PVDF film using conductive adhesive. The sensor was covered with polyester film for insulation and attached to the rubber base for a stable structure. The proposed fabrication method is simple and easy to make the sensor. The sensor has the advantages in the implementing for practical applications because its structure is flexible and the shape of the each tactile element can be designed arbitrarily. The signals of a contact force to the tactile sensor were sensed and processed in the DSP system in which the signals are digitized and filtered. Finally, the signals were integrated for taking the force profile. The processed signals of the output of the sensor were visualized in a personal computer, and the shape and force distribution of the contact object were obtained. The reasonable performance for the detection of the contact state was verified through the sensing examples.

• Journal of Chest Surgery
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• v.53 no.6
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• pp.375-380
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• 2020

Background: Prolonged ischemic time is a risk factor for primary graft dysfunction in patients who undergo heart transplantation. We investigated the effect of a supplemental cardioplegia infusion before anastomosis in patients with long ischemic times. Methods: We identified 236 consecutive patients who underwent orthotopic heart transplantation between February 2010 and December 2014. Among them, the patients with total ischemic times of longer than 3 hours (n=59) were categorized based on whether they were administered a complementary cardioplegia solution (CPS) immediately before implantation (CPS+, n=30; CPS-, n=29). Results: The mean total ischemic times in the CPS+ and CPS- groups were 238.1±30.1 minutes and 230.1±28.2 minutes, respectively (p=0.3). The incidence of left ventricular primary graft dysfunction (CPS+, n=6 [20.0%]; CPS-, n=5 [17.2%]; p=0.79) was comparable between the groups. In the Kaplan-Meier survival analysis, no significant difference in overall survival at 5 years was observed between the CPS+ and CPS- groups (83.1%±6.9% vs. 89.7%±5.7%, respectively; log-rank p=0.7). No inter-group differences in early mortality (CPS+, n=0; CPS-, n=1 [3.4%]; p=0.98) or complications were observed. Conclusion: The additional infusion of a cardioplegia solution immediately before implantation in patients with longer ischemic times is a simple, reproducible, and safe procedure. However, we did not observe benefits of this strategy in the present study.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.194-194
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• 2003

The International Agency for Research on Cancer (IARC, 1989) has classified whole diesel exhaust as probably carcinogenic to humans. Diesel exhaust particulate matter (DPM) adsorbs different chemical substances including PAHs and nitroarenes. DPM is emphasized because it is a major component of diesel exhaust, it is suspected of contributing to a health hazard. Diesel exhaust is a complex mixture of carbon particles and associated organics and inorganics, and it is not known what fraction or combination of fractions cause the health effects [cancer effects, noncancer effects (respiratory tract irritation/inflammation and changes in lung function)] that have been observed with exposure to diesel exhaust. In order to identify which chemical classes are responsible for the majority of the observed biological activities, we performed a particular biological/chemical analysis. Respirable particulate matter (PM2.5: <2.5mm) was collected from diesel engine exhaust using a high-volume sampler equipped with a cascade impactor. Particulate oganic matter was extracted by the dichloromethane/sonication method and the crude extract was fractionated according to EPA recommended procedure into seven fractions by acid-base partitioning and silica gel column chromatography. We examined genotoxic potentials of diesel exhaust particulate matter using novel genotoxicity tests, which are rapid, simple and sensitive methods for assessing DNA-damage at the DNA and chromosomal level (comet assay, in vitro MN test and Ames test). Higher genotoxic potency was observed in non polar fractions and several PAHs were detected by GC-MS, such as 1,2,5,6 dibenzanthracene, chrysene, 1,2-benzanthracene, phenanthrene and fluoranthene.