• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.2
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• pp.73-80
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• 2006

This paper describes a analysis on the chip thickness model required for cutting force simulation in ball-end milling. In milling, cutting forces are obtained by multiplying chip area to specific cutting forces in each cutting instance. Specific cutting forces are one of the important factors for cutting force predication and have unique value according to workpiece materials. Chip area in two dimensional cutting is simply calculated using depth of cut and feed, but not simply obtained in three dimensional cutting such as milling due to complex cutting mechanics. In ball-end milling, machining is almost performed in the ball part of the cutter and tool radius is varied along contact point of the cutter and workpiece. In result, the cutting speed and the effective helix angle are changed according to length from the tool tip. In this study, for chip thickness model analysis, tool and chip geometry are analyzed and then the definition of chip thickness and estimation method are described. The resulted of analysis are verified by compared with geometrical simulation and other research. The proposed chip thickness model is more precise.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.693-699
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• 2009

This paper shows mechanical properties and behaviors of macro- and micro-structures on friction stir welded specimen with 6061-T6 aluminum alloy plate. It apparently results in defect-free weld zone jointed at welding conditions like the traverse speed of 267mm/min, tool rotation speed of 2500rpm, pin inserted depth of 4.5mm and tilting angle of $2^{\circ}$ with tool dimensions such as tool pin diameter of 5mm, shoulder diameter of 15mm and pin length of 4.5mm. The tensile stress ${\sigma}_T=228MPa$ and the yield point ${\sigma}Y=141MPa$ are obtained at the condition of traverse speed of 267mm/min and tool rotation speed of 2500rpm. With the constant rotation speed, the higher traverse speed become, the higher tensile stress and yielding point become. Vickers hardness for welding zone profile were also presented.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.43-49
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• 1998

The deep hole drilling has an increasing demands because of its wide range applications and its good productivity. The BTA drills are capable of machining for having a large length to diameter ratio in single pass to higher degree of accuracy and surface finish. It's really necessary that the investigation for the deep hole drilling by the BTA drill because its required quality should be satisfied with single pass. This thesis deal with the experimental results obtained during single tube BTA system machining on SM55C steel for different machining conditions. The results of the investigation on the optimum cutting condition selecting and tool life reveals as follows. (1) The optimum cutting condition was cutting speed, V = 42 m/min and feed speed. F = 90 mm/min and the tool life was about 10 meters. (2) Surface roughness was $12\mum$ and the roundness was less using $16mum$single edge BTA drill in testing cutting condition.

• Human Ecology Research
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• v.54 no.4
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• pp.427-440
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• 2016

This study uses comparison tests of bodice basic patterns to research improvements in wearing evaluation methods based on differences in bodice basic patterns and body size. As study methods, we calculated body sizes for six types by selecting four types of bodice basic pattern and utilized bodice basic pattern size measurement tools. The study result are as follows. First, as the result of analyzing bodice basic patterns per each part and body size difference by bodice basic pattern size measurement tool, shoulder angle cover rate was J&K type 57.57%~68.41%, N type 53.13%~65.57%, L type 51.87%~63.73%, and H type 59.03%~68.20%. In the item of neck base circumference, it was J&K type 6.4~-16 mm, N type 10.7~-31.9 mm, L type -5.2~-13.4 mm, and H type -6.2~-15.4 mm. In the item of armscye circumference, it was J&K type -18.9~-59.4 mm, N type -15.2~-51.3 mm, L type -38.9~-52.7 mm, and H type -17~-42.2 mm. In the item of biacromion length, it was J&K type 23.2~-4.7 mm, N type 18.4~-10.4 mm, and H type 3.5~-5.7 mm. In the item of interscye back, it was J&K type and N type 17.6~-13.6 mm, L type 11.9~-13.6 mm, and H type 3.2~-11.8 mm. The item of interscye front was found in the sequences of study type and L type. Second, the Kruskal-Wallis test result (according to bodice basic pattern) indicated meaningful differences in items of shoulder angle cover rate, neck point to breast point, bust point-bust point, biacromion length and armscye circumference and H type had an overall higher rank.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.10
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• pp.402-407
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• 2016

Ground-coupled heat pump systems have been widely used, as they are regarded as a renewable energy source and ensure a high annual efficiency. Among the system components, borehole heat exchangers (BHE) play an important role in decreasing the entering water temperature (EWT) to heat pumps in the cooling season, and consequently improve the COP. The optimal sizing of the BHEs is crucial for a successful project. Other than the existing sizing methods, a simulation-based design tool is more applicable for modern complex geothermal systems, and it may also be useful since design and engineering works operate on the same platform. A simulation-based sizing method is proposed in this study using the well-known Duct STorage (DST) model in Trnsys. TRNOPT, the Trnsys optimization tool, is used to search for an optimal value of the length of BHEs under given ground loads and ground properties. The result shows that a maximum EWT of BHEs during a design period (10 years) successfully approaches the design EWT while providing an optimal BHE length. Compared to the existing design tool, very similar lengths are calculated by both methods with a small error of 1.07%.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.4
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• pp.530-541
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• 2008

The early stage of 3D anthropometry data has been used to obtain qualitative rather than quantitative information. However recent 3D body scanners as a common research tool for anthropormatric measurments have made it possible to obtain body surface data of sufficient resolution and accuracy. The purpose of this study is finally to develop motorcycle jacket for enhanced comfort and fit, to test the accuracy and reliability of 3D measurments of motorcycle riding posture, and to analyze the change in 20's adult male's body surface measurements between the standard anthropometric position and motorcycle riding posture. The results of this study were as follows: There were no significant differences between the study and Size Korea measurments in total traditional measuring items and most of measuring items, such as length, circumference antropometric items and interscye items though not waist back length and upper arm circumference. A comparison of 3D body surface measurments in the two different measuring postures, the bodysurface measurments such as waist front length, biacromion length, front interscye, arm length, underarm length in the motorcycle riding posture decreased than that in basic posture, whereas waist back length, back interscye, C.T.W length increased. The body surface measurments such as chest, bust, upper circumference in the motorcycle riding posture decreased than that in basic posture, whereas neck, waist, hip, elbow circumference increased.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.1
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• pp.97-101
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• 2012

Objective: With the background of aging population in China and advances in clinical medicine, the amount of operations on old patients increases correspondingly, which imposes increasing challenges to critical care medicine and geriatrics. The study was designed to describe information on the length of ICU stay from a single institution experience of old critically ill gastric cancer patients after surgery and the framework of incorporating data-mining techniques into the prediction. Methods: A retrospective design was adopted to collect the consecutive data about patients aged 60 or over with a gastric cancer diagnosis after surgery in an adult intensive care unit in a medical university hospital in Shenyang, China, from January 2010 to March 2011. Characteristics of patients and the length their ICU stay were gathered for analysis by univariate and multivariate Cox regression to examine the relationship with potential candidate factors. A regression tree was constructed to predict the length of ICU stay and explore the important indicators. Results: Multivariate Cox analysis found that shock and nutrition support need were statistically significant risk factors for prolonged length of ICU stay. Altogether, eight variables entered the regression model, including age, APACHE II score, SOFA score, shock, respiratory system dysfunction, circulation system dysfunction, diabetes and nutrition support need. The regression tree indicated comorbidity of two or more kinds of shock as the most important factor for prolonged length of ICU stay in the studied sample. Conclusions: Comorbidity of two or more kinds of shock is the most important factor of length of ICU stay in the studied sample. Since there are differences of ICU patient characteristics between wards and hospitals, consideration of the data-mining technique should be given by the intensivists as a length of ICU stay prediction tool.

• Speech Sciences
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• v.8 no.3
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• pp.161-172
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• 2001

Ankyloglossia (tongue-tie) limits movement of the tongue connected with feeding and has adverse impacts on both dental health and speech. For the patients with ankyloglossia, surgical intervention is recommended as primary treatment. This study suggests the efficient tool in determining indicatory factors for frenulotomy by quantifying Maximum Lingual Length-Protrusion (MLL-P) with boley gauge, and as a preliminary study, to show the measurement results with normal children using the tool. The subjects were 61 normal children, and the distance (MLL-P) between mandibular central incisor and tongue tip during tongue protrusion was measured with a boley gauge (Digimatic $Caliper^{(R)}$). The results of this study can be summarized as follows: (1) The mean value of MLL-P (N=61 normal children) was 21.44 mm, (2) The mean value of MLL-P was 20.69 mm in males (N=33) and 21.91 mm in females (N=28). There was no statistically significant difference between males and females, (3) The mean value of MLL-P was 19.34 mm, 21.19 mm, 22.33 mm, 22.61 mm for measurement of 3-, 4-, 5- and 6-year-old children, respectively, and (4) The mean value of MLL-P showed statistically significant difference between 3- and 5-year-old children, between 3- and 6-year old children.

• PNF and Movement
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• v.16 no.2
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• pp.179-185
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• 2018

Purpose: This study aimed to analyze the visual and spatial elements of the gait of a stroke patient who had diverse ankle weight loads applied, according to weight changes. Methods: The subject was a 57-year-old stroke patient diagnosed and hospitalized with a left intracerebral hemorrhage. A weight equivalent to 0%, 1%, and 2% of his body weight was applied to the area 5cm upward from the ankle using a Velcro strap. He was then trained on a treadmill, receiving a six-minute walk test to evaluate his gait ability. A gait analyzer was used to collect visual and spatial elements, such as gait distance, gait velocity, cadence, step length, stride length, and swing phase, according to a weight load equivalent to 0%, 1%, and 2% of his body weight. Results: According to the results of applying 0%, 1%, and 2% of his body weight on the ankle, except for gait velocity, his gait distance, cadence, step length, stride length, and swing phase were higher when 1% of his body weight was applied compared to 0% or 2% of his body weight. Conclusion: Applying a weight equivalent to 1% of the body weight to the ankle positively affected the visual and spatial element of the gait and heightened the efficiency of exercise during treadmill training, a gait-training tool generally used for stroke patients. However, the result is difficult to generalize because the number of subjects was small with only one subject.

• Physical Therapy Korea
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• v.19 no.4
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• pp.16-23
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• 2012

This study examined the effects of custom-made foot orthotics on the temporal-spatial gait parameters in children with cerebral palsy. Twenty spastic bilateral cerebral palsy (spastic CP) children (11 boys and 9 girls) participated in this study. GAITRite was used to examine the velocity, cadence, step length differential, step length, stride length, stance time, single support time, double support time, base of support, and toe angle while walking with and without foot orthotics. The differences in temporal-spatial parameters were analyzed using paired t-test. The significance level was set at .05. The velocity, cadence, both step lengths, both stride lengths, both bases of support and right toe angle significantly increased when the children with spastic CP with foot orthotics compared to without foot orthotics (p<.05). The step length differential between the two extremities, left stance time and left single support time, significantly decreased with foot orthotics (p<.05). Right stance time, right single support time, both double support times and left toe angle showed little change (p>.05). This study demonstrated that foot orthotics were beneficial for children with spastic CP as a gait assistance tool.