• Journal of Preventive Medicine and Public Health
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• v.32 no.3
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• pp.361-373
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• 1999

Objectives: Receive Operating Characteristic(ROC) curve with the area under the ROC curve(AUC) is one of the most popular indicator to evaluate the criterion validity of the measurement tool. This study was conducted to develop a standardized questionnaire to discriminate workers at high-risk of work-related musculoskeletal disorders using ROC analysis. Methods: The diagnostic results determined by rehabilitation medicine specialists in 370 persons(89 shipyard CAD workers, 113 telephone directory assistant operators, 79 women with occupation, and 89 housewives) were compared with participant's own replies to 'the questionnair on the worker's subjective physical symptoms'(Kwon, 1996). The AUC's from four models with different methods in item selection and weighting were compared with each other. These 4 models were applied to 225 persons, working in an assembly line of motor vehicle, for the purpose of AUC reliability test. Results: In a weighted model with 11 items, the AUC was 0.8155 in the primary study population, and 0.8026 in the secondary study population(p=0.3780). It was superior in the aspects of discriminability, reliability and convenience. A new questionnaire of musculoskeletal disorder could be constructed by this model. Conclusion: A more valid questionnaire with a small number of items and the quantitative weight scores useful for the relative comparisons are the main results of this study. While the absolute reference value applicable to the wide range of populations was not estimated, the basic intent of this study, developing a surveillance fool through quantitative validation of the measures, would serve for the systematic disease prevention activities.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.530-534
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• 2002

Background: In aortic surgery, division and ligation of the left brachiocephalic vein(LBV) may improve exposure of the aortic arch but controversy continues about the safety of this division and whether a divided vein should be reanastomosed after arch replacement was completed. The safety of LBV division and the fate of the left subclavian venous drainage after LBV division were studied. Material and Method: From November 1998 to January 2001, planned division and ligation of the LBV on the mid-line after median sternotomy was peformed in 10 patients during the aortic surgery with the consideration of local anatomy and distal aortic anastomosis. Assessment for upper extremity edema and neurologic symptoms, measurement of venous pressure in the right atrium and left internal jugular vein, and digital subtraction venography(DSV) of the left arm were made postoperatively. Result: In 10 patients there was improvement in access to the aortic arch for procedures on the ascending aorta or aortic arch. The mean age of patients was 62 years(range 24 to 70). Follow-up ranged from 3 weeks to 13 months. One patient died because of mediastinitis from methicilline-resistant staphylococcus aureus strain. All patients had edema on the left upper extremity, but resolved by the postoperative day 4. No patient had any residual edema or difficulty in using the left upper extremity during the entire follow-up period. No patient had postoperative stroke. Pressure difference between the right atrium and left internal jugular vein was peaked on the immediate postoperative period(mean peak pressure difference = 25mmHg), but gradually decreased, then plated by the postoperative day 4. In all DSV studies left subclavian vein flowed across the midline through the inferior thyroid venous plexus. Conclusion: We conclude that division of LBV is safe and reanastomosis is not necessary if inferior thyroid vein, which is developed as a main bridge connecting the left subclavian vein with right venous system, is preserved.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.434-441
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• 2014

This study is purposed to measure airborne asbestos concentrations at demolition sites and surrounding areas of asbestos containing buildings in Seoul and examine whether the measurement results correspond with allowable exhaust standard for asbestos of the Asbestos Safety Control Act. The airborne asbestos concentrations for 37 sites were below the detection limit ($7fiber/mm^2$) in 101 (35%) out of 288 samples. The whole average airborne asbestos concentration in 37 sites was $0.003{\pm}0.002f/cc$(max 0.0013 f/cc) and almost the whole airborne asbestos concentrations were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act. So possibility of asbestos exposure is not yet a major concern at current levels for sites demolished of asbestos containing buildings in Seoul. Looking at each sampling point, the average airborne asbestos concentrations in boundary line of site, entrance of sanitation, around the workplace (in), around the workplace (out), negative pressure units, storage area for waste, outlet for waste and residential area of residents were respectively $0.002{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.004{\pm}0.002f/cc$, $0.005{\pm}0.004f/cc$, $0.005{\pm}0.003f/cc$ and $0.003{\pm}0.002f/cc$. As a result, all sampling points of study were satisfied with allowable exhaust standard for asbestos, 0.01 f/cc, of the Asbestos Safety Control Act.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.332-350
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• 2019

Zonal hydrographic section measurements at $39.7^{\circ}N$ were conducted between $129.0^{\circ}E$ and $131.3^{\circ}E$ from August 7 to 25 in 2017 using an underwater glider. The glider traveled about 440 km for about 18 days along the 106 line of the regular shipboard measurements in the National Institute of Fishery Science (NIFS) and obtained twice a hydrographic section with high horizontal resolution. Even under the strong East Korea Warm Current with maximum speed of 0.8 m/s across the section, the glider successfully maintained the designated path within an RMS distance of 400 m. By comparing with the NIFS shipboard hydrographic section, it is confirmed that high spatial resolution measurements obtained from a glider were necessary to properly observe front and eddy variability in the East Sea where a typical spatial scale is smaller than the open oceans. From the glider section measurements, a new lens-shaped eddy was found in the thermocline. The lens-shaped anticyclonic eddy had 10~13 km in horizonal width and about 200 m in height like a typical submesoscale eddy resided within the thermocline, which was firstly named as Korea intrathermocline eddy (Keddy). The Keddy has the distinguishing characteristics of a typical intrathermocline eddy, such as a central core with anomalously weak stratification, a convex shaped lens bounded by the stratification anomaly, an interior maximum of velocity at 170 m, no surface appearance of the geopotential field, a small or comparable horizontal width relative to the first baroclinic Rossby radius of deformation, and the Rossby nubmer of 0.7.

• The KIPS Transactions:PartD
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• v.12D no.3 s.99
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• pp.417-428
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• 2005

Today, IT organizations perform projects with vision related to marketing and financial profit. The objective of realizing the vision is to improve the project performing ability in terms of QCD. Organizations have made a lot of efforts to achieve this objective through process improvement. Large companies such as IBM, Ford, and GE have made over $80\%$ of success through business process re-engineering using information technology instead of business improvement effect by computers. It is important to collect, analyze and manage the data on performed projects to achieve the objective, but quantitative measurement is difficult as software is invisible and the effect and efficiency caused by process change are not visibly identified. Therefore, it is not easy to extract the strategy of improvement. This paper measures and analyzes the project performance, focusing on organizations' external effectiveness and internal efficiency (Qualify, Delivery, Cycle time, and Waste). Based on the measured project performance scores, an OT (Opportunity Tree) model was designed for optimizing the project performance. The process of design is as follows. First, meta data are derived from projects and analyzed by quantitative GQM(Goal-Question-Metric) questionnaire. Then, the project performance model is designed with the data obtained from the quantitative GQM questionnaire and organization's performance score for each area is calculated. The value is revised by integrating the measured scores by area vision weights from all stakeholders (CEO, middle-class managers, developer, investor, and custom). Through this, routes for improvement are presented and an optimized improvement method is suggested. Existing methods to improve software process have been highly effective in division of processes' but somewhat unsatisfactory in structural function to develop and systemically manage strategies by applying the processes to Projects. The proposed OT model provides a solution to this problem. The OT model is useful to provide an optimal improvement method in line with organization's goals and can reduce risks which may occur in the course of improving process if it is applied with proposed methods. In addition, satisfaction about the improvement strategy can be improved by obtaining input about vision weight from all stakeholders through the qualitative questionnaire and by reflecting it to the calculation. The OT is also useful to optimize the expansion of market and financial performance by controlling the ability of Quality, Delivery, Cycle time, and Waste.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.310-317
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• 2015

Purpose: The purpose of this study was to evaluate the validity of reference points for edentulous patient by examining the correlation of teeth and face, and intraoral anatomic landmarks. Materials and methods: We examined a facial outline, length, bizygomatic width, nasion - gnathion length, glabella - nasion distance in 270 men and 280 women satisfied with inclusion criteria from Seoul National School of Dentistry. The shape of maxillary central incisor, mesiodistal crown width and length of maxillary 6 incisors, distance from incisive papilla to labial surface of maxillary central incisor, and perpendicular distance from incisive papilla to intercanine line were measured in the stone model. We analyzed the ratio and relevant relation statistically. Results: The probability on having the same shape of face and the relative same shape maxillary incisor was 55.56% and 46.43% for men and women. The facial length proved to be a more valuable measurement in women in the tooth selection. The ratio of bizygomatic width to mesiodistal width of maxillary central incisor, and the ratio of bizygomatic width to width of maxillary 6 incisors were 16.8 : 1 and 3.0 : 1 and were positively correlated with each other. The distance of the canines from the maxillary incisal papilla was $1.33{\pm}1.28mm$. The distance between the center of the incisal papilla and the labial surface of their maxillary central incisor was $9.23{\pm}1.20mm$. Conclusion: It was showed that anatomical reference points in tooth selection and arrangement for edentulous patient are useful and have validity in our limited study.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.321-327
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• 2013

Purpose: To investigate a correlation between vertical fixation disparity and stereopsis by analyzing distribution of types of vertical fixation disparity. Methods: In this study, RANDOT(R) stereotest partly using random dot was used in stereopsis tests. The vertical fixation disparity in close proximity categorized fixation disparity slope into six types on the basis of the result of measurement in when two thin lines, one for one eye looks, become overlapped as a line by adding into prism with Wesson fixation disparity card while maintaining a distance of 25 cm from patients. Results: In the types of near vertical fixation disparity curve, targeting 43 people, the first type 55.82% was the most distributed, the second type is the least 23.25%, the third type of 4.65%, the fourth type of 4.65%, the fifth type of 6.98%, the sixths types of 4.65% were distributed. The result of a correlation analysis, which shows the degree of linear correlation between two variables, represented that stereopsis is not correlated with Y-intercept (r = -0.07) which show vertical fixation disparity, associated phoria (r = -0.03) and dissociated phoria (r = -0.00), but it was not statistically significant (p>0.05). Fixation disparity slope of vertical fixation disparity (r = 0.36) was shown to have a positive correlation with stereopsis. It has a low positive correlation and a meaningful statistics (p<0.05). The Y-intercept which indicates vertical fixation disparity was also not associated with stereopsis (r = -0.07) and dissociated phoria (r = -0.03), and this was not statistically significant (p>0.05), while it had a high correlation as well as a statistically significant with associated phoria (r = 0.89). There was a negative correlation between Y-intercept and fixation disparity slope of vertical fixation disparity (r = -0.33). It showed a low relationship but statistically valuable (p>0.05). As a result of regression analysis, the stereopsis was changed as 7.631" if vertical fixation disparity changes 1' and the vertical fixation disparity changed as 0.017' if stereopsis changes 1', and the change was statistically significant (p<0.05). Conclusions: The study shows that there is a low correlation between stereopsis and vertical fixation disparity, and it is difficult to determine stereopsis only using vertical fixation disparity. Therefore, it suggests other factors above vertical fixation disparity have greater influence on stereopsis.

• Journal of IKEEE
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• v.23 no.4
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• pp.1461-1464
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• 2019

In this paper, we propose the development of embedded board for integrated radiation exposure protection fireman's life-saving alarm capable of location tracking and radiation measurement. The proposed techniques consist of signal processing unit, communication unit, power unit, main control unit. Signal processing units apply shielding design, noise reduction technology and electromagnetic wave subtraction technology. The communication unit is designed to communicate using the wifi method. In the main control unit, power consumption is reduced to a minimum, and a high performance system is formed through small, high density and low heat generation. The proposed techniques are equipment operated by exposure to poor conditions, such as disaster and fire sites, so they are designed and manufactured for external appearance considering waterproof and thermal endurance. The proposed techniques were tested by an authorized testing agency to determine the effectiveness of embedded board. The waterproof grade has achieved the IP67 rating, which can maintain stable performance even when flooded with water at the disaster site due to the nature of the fireman's equipment. The operating temperature was measured in the range of -10℃ to 50℃ to cope with a wide range of environmental changes at the disaster site. The battery life was measured to be available 144 hours after a single charge to cope with emergency disasters such as a collapse accident. The maximum communication distance, including the PCB, was measured to operate at 54.2 meters, a range wider than the existing 50 meters, at a straight line with the command-and-control vehicle in the event of a disaster. Therefore, the effectiveness of embedded board for embedded board for integrated radiation exposure protection fireman's life-saving alarm has been demonstrated.

• Investigative Magnetic Resonance Imaging
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• v.10 no.1
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• pp.1-7
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• 2006

Purpose : Recent development of diffusion tensor imaging enables the evaluation of the microstructural characteristics of the brain white matter. However, optimal imaging parameters for diffusion tensor imaging, particularly concerning the number of diffusion gradient direction, have not been studied thoroughly yet. The purpose of this study was to evaluate the influence of the number of diffusion gradient direction on the fiber tracking of the white matter. Materials and methods : 13 healthy volunteers (ten men and three women, mean age 30 years, age range 23-37 years) were included in this study. Diffusion tensor imaging was performed with different numbers of diffusion gradient direction as 6, 15, and 32, keeping the other imaging parameters constant. The imaging field ranged from 1 cm below the pons to 2-3 cm above the lateral ventricle, parallel to the anterior commissure-posterior commissure line. FA (fractional anisotropy) maps were created via image postprocessing, and then FA and its standard deviation were calculated in the genu and the splenium of the corpus callosum on each of FA maps. Fiber tracking of the corticospinal tract in the brain was performed and the number of the reconstructed fibers of the tract was measured. FA, standard deviation of FA and the number of the reconstructed fibers were compared statistically between the different diffusion gradient directions. Results : FA is not statistically significantly different between the different diffusion gradient directions. By increasing the number of diffusion gradient direction, standard deviation of FA decreased significantly, and the number of the reconstructed fibers increased significantly. Conclusion : The higher number of diffusion gradient direction provided better quality of fiber tracking.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.643-659
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• 1997

For the total treatment of skeletal malocclusions, 3-dimensional evaluation and diagnosis are essential. Although anteroposterior discrepancies can be evaluated through various methods, the satisfactory methods for evaluations of facial asymmetry and transverse discrepancies are yet to be found. The adequate diagnosis and treatment of transverse discrepancies may be more important in the maintenance of functional occlusion as well as for the stability of results obtained from orthognathic surgery than the anteroposterior or vertical discrepancies. Since the soft tissue effects from the transverse discrepancies may not be pronounced, especially when combined with anteroposterior or vertical discrepancies which have prominent characteristics, the differentiation of their effects may be difficult from visual inspection alone. Therefore it is essential that the normal facial proportions would be established from the posteroanterior cephalometry as a reference for the accurate diagnosis and treatment. The present study evaluates 76 subjects from Yonsei University freshmen with normal facial symmetry and occlusion. Posteroanterior cephalograms were taken from the subjects and the normal values and facial proportions are obtained. The results are as follows. 1. The transverse and vortical values from posteroanterior cephalometry and their ratio, with means and standard deviations are calculated. 2. The ratio of vertical values to transverse values is 0.837 (male 0.836, female 0.841). 3. The Proportion of maxillary and mandibular widths is 0.747 (male 0.745, female 0.752), with statistically significant correlation. 4. Various degree of significant correlations are observed in the following craniofacial widths; (Cranial width, Bizygomaticofrontal suture width, Facial width, Maxillary width, Upper & Lower Intermolar width, Mandibular width). 5. Although the facial height as well as other line measurements increase as the facial widths increase, angle measurement ($Bj\ddot{o}rk$ Sum, Mandibular Plane Angle, Gonial Angle), decreases and posterior to anterior facial height ratio increases, therefore indicating the tendency for a brachycephalic facial type. These results may be used as references for the treatment planning in orthognathic and orthodontic treatments for the dentofacial deformity patients.