• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.12
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• pp.1471-1481
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• 2009

In diesel engines, it is inevitable that the torsional vibration is produced by the fluctuation of engine torque. Therefore, it is necessary to establish preventive measures to diminish the torsional vibration. The sleeve spring type damper is one of the preventive measures for reducing the torsional vibration. In this study, the closed form equations to predict the spring constant of a sleeve spring and the torsional characteristics of the torsional vibration damper are proposed to calculate stiffness of the damper and verified their availability through the finite element analysis and experiments. And the stability of the sleeve spring torsional vibration damper is verified by analyzing the inner star and outer star, which are the core parts of the damper, and 2-roll bending process is proposed to manufacture sleeve spring. The program to calculate the initial radius including spring-back effect is developed, and the FEA method to analyze elasto-plastic problem was verified through analysis of 90$^{\circ}$bending process. The results of the analysis are in good agreements with those of the experiments. The newly proposed method can be used as an advanced technique that remarkably curtails cost of production and replaces the conventional forming.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.5
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• pp.604-610
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• 2014

In this paper, the analysis and the experiment of independent multi-phase BLDC motor are performed. The back-emf, iron loss analysis are performed by the finite element method and compared with experimental results. The independent multi-phase BLDC motor is manufactured and to measure the efficiency of the motor, evaluation system is also manufactured including the load generator. By comparing the analytic and the experimental results, the effectiveness of the analysis model is verified when calculating the efficiency of the motor.

• The Research Journal of the Costume Culture
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• v.18 no.6
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• pp.1242-1253
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• 2010

The purpose of this study is to suggest a designing method with excellent body suitability by analyzing clothingwearing porosity, comparing and analyzing patterns, and evaluating outer appearances by designing a prototype of study applied with design measurements for categories that have influence on the outer appearance of clothing through diverse research methods, by comparing and analyzing bunka and new bunka style basic pattern, which are proportional basic patterns most frequently used in schools for educational use to design bodice pattern for elderly women in their late 60s. As for the process of this study, the first stage selected study subjects, measured bodies. The second stage compared patterns of bunka and new bunka style basic pattern and evaluated outer appearances that deduced important pattern designing categories to design upper-torso bodice pattern of elderly women. The results of this study are as following ; As a result of comparing and analyzing bunka and new bunka style basic pattern, overall evaluation of outer appearance was excellent for new bunka style basic pattern, and bunka basic pattern received better reviews for the width and depth of front neck. In terms of waist circumference, waist front length, bust point location and bust point-bust point, bunka and new bunka style basic patterns showed a significant difference. new bunka style basic pattern had 4.5cm larger front armhole depth than bunka basic pattern, so it was evaluated to have more appropriate front armhole length, bust point location, and bust point-bust point. Through observation for primary excellent categories and precedent studies, 7 categories of front neck width, front neck depth, front interscye, back neck width, back neck depth, back interscye, and back armhole depth were deduced to have relations to the extra room around arm holes and waist that affect pattern designing method and porosity and evaluations of outer appearance.

• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.4
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• pp.69-79
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• 2019

This study aims to seek knitting methods that can enhance the neck design of seamless knitwear and to find out how to improve the designs by comparing and analyzing the characteristics of the knitting methods used for v-neck pullovers. The investigator analyzed the characteristics of the knitting methods and assessed the wearing sensation by using six different pieces of clothing for the experiment. The results were analyzed based on a variance analysis (ANOVA). Among the items showing significant results, the Duncan-test was used for more intensive research. As a result, while using the basic pattern of knitting methods, Experiment Clothes A ended up binding on the back neckline, and not making the hem of back. Also, the neck was the widest. In the case of the special neck, Experimental Clothes B (1:1), which had the least number of the knitting course in relation to the knitting ratio, the bottom part of the back body had the most wrinkles. According to the result of wearing sensation, the front part, the side part, and the back part showed similar results (p<0.000) in all items. Specifically, the appearance of the Experiment Clothes A (normal) in both the front and rear aspects were evaluated as the best. In the case of the special neck, the Experimental Clothes F was ranked the highest, whereas the Experimental Clothes B (1:1) was ranked the lowest. Based on the results of the study, it seems possible to provide concrete and technical data for the planning of unique and productive designs. With regard to seamless knitwear neck designs, a comparative analysis of the knitting method of v-neck pullovers will be of practical use in the development and manufacturing of the product.

• Korean Journal of Human Ecology
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• v.10 no.4
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• pp.379-390
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• 2001

The purpose of this study is to investigate the fitness according to drafting method of the block patterns for women in Korea. The major findings of this study are as follows: 1. According to comparative analysis of required measurements, two measurements of back length and bust girth are used in Proportional Drafting Method (Munhwa). In case of Compromise Drafting Methods are used across chest, across back, bust length, bust width, full length in front, across shoulder and shoulder length in addition to back length and bust girth. The type of Armstrong as a Short Measure Drafting Method uses 10 measurements for the drafting the bodice. 2. While Esmod block pattern arid Armstrong's block pattern are the lightest in full width and other widths. Rasara block pattern is the most ample. In Lee, Myung-hee's block pattern and Lee, Hyung-sook's block pattern, amounts of drooping are decided $3{\sim}4cm$, but drooping amounts of other block patterns are decided corresponding to real measurements. While cap height in Esmod and Armstrong's sleeve patterns are directly measured Armhole length of the block pattern, cap height of other sleeve patterns are used armhole depth and cap height length as well as armhole length. 3. When analyzing to indirect measurements, Esmod block pattern shows the least different between full length of block pattern and that of body form. Munhwa block pattern and Kim, Hyosook's block pattern are mostly same to body form back length. However all of the block patterns are sheller than body form length. In case of Suh, Wansuk's block pattern, across back and across chest are same size, but other block patterns show difference between across back and across chest. Most block patterns' neck width in front and bach bodice are almost same. Front neck width is generally bigger than back neck width in some cases.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.345-350
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• 2009

The endpoint of the Yangbuk tunnel constructed at the national road between Gyeongju and Gampo is composed of massive cutting because the road is driven through the sides of mountain. PAP(Prestressed Anchor and PC Pannel) retaining wall as a slope stability method was established over this section. Part of the anchor in PAP wall became broken after six months. We performed inverse analysis through its measurements obtained until that time. An geological investigation to confirm the condition of ground layering and the attraction force test to find as to whether some errors might be present in the anchor were made. According to the back analysis, it was turned out that the value with soil parameter 90% that was applied to the original design was pertinent. In the redesign, the permissible stress in the anchor body was changed from 306 kN to 591 kN and 784 kN and the fixation position was increased from 11.0 m to 23.0 m. Nevertheless, five months have passed since the exchange of the anchor, the measurement results validate that stable state has been maintained. This research is considered a case that the immediate maintenance helps prevent the slope accidents.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1637-1640
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• 2005

This paper presents a technique for electromagnetic field analysis on surge response due to Mid-span back-flashovers effects in lightning protection system of 500 kV EHV single circuit transmission tower by the neural networks method. These analyses are based on modeling lightning return stroke as well as on coupling the electromagnetic fields of the stroke channel to the line. The ground conductivity influences both the electric field as well as the coupling mechanism and hence the magnitude and wave shape of the induced voltage. The technique can be used to analyzed the corona voltage effect, the effective of stroke to the span tower, the surge impedance of transmission lines. The maximum voltage from flashovers effects in the lines. The model is compatible with general electromagnetic transients programs such as the ATP-EMTP. The simulation results show that this study analyses for time-domain with those produced by a cascade multi-section model, the surge impedance of a full-sized tower hit directly by a lightning stroke is discussed.

• International Journal of Highway Engineering
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• v.17 no.5
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• pp.25-31
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• 2015

PURPOSES: The objective of this study is to analyze the relationship between the FWD back-calculated modulus and dynamic modulus of asphalt layers for existing asphalt pavements. METHODS: To evaluate the dynamic modulus of the asphalt mixture in the existing and new asphalt layers, the uniaxial direct tension test was conducted on small asphalt specimens obtained from the existing asphalt-covered pavements. A dynamic modulus master curve was estimated by using the uniaxial direct tension test for each asphalt layer. The falling weight deflectometer (FWD) testing was conducted on the test sections, and the modulus values of pavement layers were back-calculated using the genetic algorithm and the finite element method based back-calculation program. The relationship between measured and back-calculated asphalt layer moduli was examined in this study. The normalized dynamic modulus was adopted to predict the stiffness characteristics of asphalt layers more accurately. RESULTS: From this study, we can conclude that there is no close relationship between dynamic modulus of first layer and back-calculated asphalt modulus. The dynamic moduli of second and third asphalt layers have some relation with asphalt stiffness. Test results also showed that the normalized dynamic modulus of the asphalt mixture is closely related to the FWD back-calculated modulus with 0.73 of R square value. CONCLUSIONS: The back-calculated modulus of asphalt layer can be used as an indicator of the stiffness characteristics of asphalt layers in the asphalt-covered pavements.

• The Korean Journal of Pain
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• v.10 no.2
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• pp.214-219
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• 1997

Background: Epidural neural blockade with local anesthetics combined with steroids has been in clinical trials for patients with low back pain. But pain treatment of low back pain remains somewhat problematic. Many patients with low back pain have epidural fibrosis and adhesions proved with magnetic resonance imaging(MRI) examination. These findings might play an important role in the origin of back pain. Present study was aims to investigate the effect of epidural adhesiolysis in patients with low back pain. Methods: We investigated 76 patients suspected with epidural fibrosis and adhesion was suspected. Nerve pathology was demonstrated and epidural fibrosis suspected or proved with MRI examination. 17G needle specially designed by Racz was inserted at sacral hiatus and catheter was inserted untill its tip was located at lesion site under fluoroscopic guidance. Injection of contrast dye was achieved and prospected spread of agents. Injection of 0.25% bupivacaine, triamcinolone, and 10% hypertonic saline via catheter were carried out daily for 3 days. Evaluation included assessment of pain relief (Numerical Rating Scale; NRS) post-epidural adhesiolysis 3 days, 1 week, and 3 months. We also looked for complication of epidural adhesiolysis. Results: Statistical analysis(Friedman nonparametric repeated measures test and Dune's multiple comparison test) demonstrated NRS was significantly less during 3 months after epidural adhesiolysis(P<0.05). Especially, there is a extremely significance in post-epidural adhesiolysis 3 days (P<0.001). Only four patients reported any complications the most common symptom among three persistent headache but disappeared after a few months without residual sequelae. Conclusion: We conclude epidural adhesiolysis is a safe and effective method of pain therapy for low back pain with proven lumbo-sacral fibrosis and adhesion. A direct visualization by epiduroscopy may be more useful to the resulting functional changes after epidural adhesiolysis.

• Journal of muscle and joint health
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• v.14 no.2
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• pp.118-126
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• 2007

Purpose: The purpose of the study was to examine the relationship between the level of pain and depression in middle-aged women with chronic low back pain. Method: A descriptive correlational research design was utilized. The participants were middle-aged women who visited two back pain clinics in Wonju from October, 2006 through February, 2007. A total of 195 low back pain patients agreed to participate in this study, and data from 177 were analyzed. Data was collected using a questionnaire which included Visual Analogue Scale (VAS), Center Epidemiology Studies Depression Scale(CES-D), and general characteristics. Descriptive statistics, t-test, ANOVA and Pearson correlation coefficients were utilized in the analysis. Results: The mean score for chronic low back pain as measured by the VAS was 4.99 (SD 2.41). The average score for depression as measured by the CES-D was 22.00 (SD 10.18). There was a significant relationship between the level of pain and depression (r=.372, p<.001). Conclusion: Nurses need to take into consideration depression of middle-age women with chronic low back pain for assessment and intervention. In the future, developing a strategy for integrating intervention of pain-control and depression will be needed in nursing care for middle-aged women with chronic low back pain.