• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.187-197
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• 2001

The change of the vertical dimension is of fundamental importance to the orthodontist. However, the choice between the two methods of treatment, extraction versus nonextraction, is not clear. It is not verified that the extraction method decreases vertical dimension, or nonextraction methods result in an increase in vertical dimension. The purpose of this study was to evaluate the changes of vertical dimension of face after the orthodontic treatment with standard edgewise technique, and to compare them in relation to facial types and bicuspid extraction. The subjects consisted of 165 orthodontic patients (77 of adolescents, 88 of adults), and was divided into vertical nonextraction (VN) group, vertical extraction (VE) group, horizontal nonextraction (HN) group, horizontal extraction (HE) group. Pre-and Post-treatment cephalograms were taken with standard method, traced, and digitized for each subject. The comparison of the measurements were statistically executed with Student's t-test. The results were as follows : 1. The facial height and molar height were increased after orthodontic treatment in the all groups. 2. No significant difference was found in the facial height change between the vertical and horizontal groups. 3. No significant difference was found in the facial height change between the extraction and nonextraction groups. 4. As the upper molars were extruded in adolescents group and lower molars were extruded in adults group, lower anterior facial height (LAFH) was increased. 5. None of the pretreatment variables correlates to the change of lower anterior facial height (LAFH).

• Clinical and Experimental Reproductive Medicine
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• v.36 no.4
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• pp.249-254
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• 2009

Objective: The aim of this study was to compare the fertilization and cleavage rates of human in vitro matured oocytes after fertilized by conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Methods: A total of 135 GV stage oocytes were obtained from 59 women who received ovarian stimulation and IVF during Jan 2007 to Oct 2008. Ovarian hyperstimulation was performed using hMG or recombinant FSH with GnRH antagonist and then ovulation triggered by recombinant hCG. The immature oocytes obtained from stimulation cycles were cultured in IVM medium up to 48 hrs; commercial medium supplemented with rFSH 75 mIU/mL, rhCG 0.5 IU/mL and rEGF 10 ng/mL. The in vitro matured oocytes were fertilized by conventional IVF (41 GV oocytes) or ICSI method (94 GV oocytes). Results: Maturation rate were 51.2% and 59.6% in conventional IVF group and ICSI group, respectively. There was no significant difference in fertilization rates between two groups; 71.4% and 80.4%, respectively. The cleavage rate was also similar in two groups. Conclusion: The presented data suggest that conventional IVF has comparable fertilization and cleavage potential compared with ICSI as the insemination method of immature human oocytes obtained from stimulated cycle.

• Journal of Embryo Transfer
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• v.26 no.3
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• pp.153-158
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• 2011

This study was performed in order to simplify the operation and minimize stress of donor and be readily available in the field with low cost and high quality embryos using the Direct Embryo Collection (DEC). Donors, at random stages of the estrous cycle, received a CIDR. 7 days later, 200 mg FSH was treated with 40, 30, 20, 10 mg FSH levels in declining doses twice daily by intramuscular injection for 4 days. On the 3rd day administration of FSH, 25 mg $PGF_2{\alpha}$ was administered and CIDR was withdrawn. After FSH injections were complete, donors were artificially inseminated twice at 12 hr intervals. The donor cattle received 250 ${\mu}g$ GnRH at time of 1 st insemination and embryos were recovered 8 days after the 1st insemination. Embryo collection from superovulated donors was performed to flushing by non-surgical methods of 3-way, 2-way and DEC (l-way). The average number of recovered embryos were 11.25${\pm}$0.63, 12.5${\pm}$0.65 and 11.75${\pm}$0.48 from operations of 3-way, 2-way and DEC methods, respectively. There were no significant differences among the embryo collection methods. Also, The average number of transferable embryos were 6.25${\pm}$0.48, 7.25${\pm}$0.48 and 7.25${\pm}$0.63 from each embryo collection procedures. The number of transferable embryos was no differences among the 3-way, 2-way and DEC methods, respectively. Meanwhile, the ratio of transferable embryos for all recovered embryos from DEC methods was higher as 61.7 % than 55.6 %, 58 % from methods of 3-way, 2-way. And the flushing solution required for recovering embryos by DEC method was significantly lower as 0.28${\pm}$0.32 1 than 1.8${\pm}$0.12 1, 1.75${\pm}$0.10 1 from 3-way, 2-way methods (p<0.05). Also, the time required for recovering embryos by DEC methods was significantly lower as 27${\pm}$2 min than 51${\pm}$3, 45${\pm}$2 min, respectively (p<0.05). In conclusion, these results suggest that DEC method for embryo collection may be effectively used for production of in vivo embryos using less flushing solution and, it might be effectively available in the field compared to conventional embryo recovery methods using 3-way or 2-way balloon catheter.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.5
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• pp.338-345
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• 2003

Purpose : This study was intended to perform cephalometric comparison between the patients with and without obstructive sleep apnea (OSA). The factors influencing the OSA in the lateral cephalogram was also investigated. Patient and Method : Twenty four patients who visited Sleep Disorder Clinic in Dongsan Medical Center, Keimyung University and evaluated with polysomnograph(PSG) and cephalogram were included in the study. The patients had apnea-hypopnea episode(AHI) over 10 times per hour was diagnosed as OSA after overnight PSG. To evaluate hard and soft tissue profile, cephalometric radiogram were taken at maximal intercuspation(P1) and mandibular protruding position(P2). The diffefence between the OSA and normal group were evaluated statistically and the stepwise regression analysis was applied to analyse the cephalometric influencing factors to OSA. Result : The OSA Group(n=14) had significantly higher Body Mass Index(BMI) than control group(n=10). Lower facial height(ANSGn) was longer in OSA group. However statistically significant difference was not detected in other anteroposterior craniofacial measurements. The soft palate lenth (PNS-P), hyoid position (MP-Hyoid) had positive correlation between AHI (r=0.496, r=0.413, respectively, p<0.05). However, the measurements of oropharyngeal airway was not different between the two groups. The hypothesis, the antero-posteriorly narrow oropharyngeal airway might aggravate the airway resistance and can give rise to higher AHI, was not accepted in the study. This can be attributed by inclusion of the patients performed uvulopalatopharyngoplasty because of the tonsilar or soft palate hypertrophy in the present study. The results of regression analysis revealed that PNS-P, upper airway width(Nph1), upper facial heght(N-ANS), and lower facial height(ANS-Gn) could influence the degree of AHI (F value < 0.0001, $R^2$ = 0.829). Conclusion : We suggest lateral cephalogram may utilized as a useful method to evaluate OSA. The patient with long soft palate, narrow upper airway width, long upper & lower facial height can be expected to have high risk of OSA. However, it should be emphasized the comphrehensive intraoral inspection including soft palate and tonsilar hypertrophy because lateral cepahlogram cannot visualize oropharyngeal status completely.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.350-366
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• 2016

Objectives: No 3D anthropometric analyses have been conducted for Korean children's faces for the purpose of designing respiratory protective devices. The aim of this study was to develop masks against yellow dust and fine particulates, particularly for children in Korea. Methods: This study utilized a 3D scanning method to obtain 16 facial anthropometric data from children, ages of 5 to 13 years old. A total of 144 boys and girls were recruited from the kindergarten, elementary schools and middle schools in Seoul. With facial dimensions obtained, cluster analysis was performed to categorize them into similar facial groups. For each cluster, an optimal mask was designed and manufactured using a 3D printer. In addition, lung function data were obtained from 62 subjects and compared with those of normal adults. The pulmonary physiological results were subsequently used to suggest a test method for mask certification. Results: Facial shapes were classified into tree clusters: small, medium, and large. The face width and length for the first group were small with high nosal protrusion. The face width and length for the second group were the largest among the three clusters. The third group had the largest angle of nose root - gnathion(n-prn-gn). Age was the most significant variable in the facial dimensions. Children's pulmonary physiological capacity was about 60% of adults' capacity. The results of fit test using the prototype masks developed showed very good fits for children. Conclusions: For Korean children, three mask sizes will be sufficient and practical for providing protection against yellow dust and fine particulates. Anthropometric data obtained using digitalized 3D face analysis can be very effective for designing respiratory devices. 3D images can be accurate and easily measured for multiple dimensions, particularly for curved areas of the face. It is imperative to adopt different test methods for certifying respiratory protective devices for children, since their pulmonary physiological capacity is inferior compared with that of adults.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.1
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• pp.25-33
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• 2004

The purpose of this study was to evaluate the postoperative stability of the severe open bite or mandibular prognathic patients after mandibular set back surgery by Obwegeser II method. There were 19 patients who had been undergone Obwegeser II method. The horizontal and vertical position of the cephalometric points were measured preoperation and immediate postoperation, postoperative 1 month, postoperative 6 months ; were analyzed by linear measurement to evaluate changes in skeletal landmark and the relapse was compared between open bite group and prognathism group. By the operation, horizontal change of B was $6.84{\pm}4.35mm$ and vertical change of B was $6.28{\pm}3.25mm$ in open bite group and horizontal change of B was $14.20{\pm}4.81mm$ and vertical change of B was $1.99{\pm}2.66mm$ in prognathism group, horizontal change of Pog was $3.82{\pm}5.71mm$ and vertical change of Pog was $5.38{\pm}2.11mm$ in open bite group and horizontal change of Pog was $13.24{\pm}5.99mm$ and vertical change of Pog was $1.91{\pm}0.94mm$ in prognathism group. Between immediate postoperation and postoperative 1 month, all skeletal landmarks change was no statistical difference (p>0.05) and there were no statistical difference between open bite group and prognathism group except x-Me landmark (p>0.05). Between postoperative 1 month and 6 months, horizontal change of B was $0.12{\pm}1.35mm$ and vertical change of B was $1.47{\pm}1.48mm$ in open bite group and horizontal change of B was $1.43{\pm}1.35mm$ and vertical change of B was $0.82{\pm}1.99mm$ in prognathism group, horizontal change of Pog was $0.13{\pm}1.40mm$ and vertical change of Pog was $0.88{\pm}1.71mm$ in open bite group and horizontal change of Pog was $1.08{\pm}1.74mm$ and vertical change of Pog was $0.47{\pm}1.57mm$ in prognathism group (p>0.05) and there were no statistical difference between open bite group and prognathism group (p>0.05). Between immediate postoperation and postoperative 6months, horizontal change of B was $0.24{\pm}1.17mm$ and vertical change of B was $1.87{\pm}1.63mm$ in open bite group and horizontal change of B was $1.54{\pm}1.55mm$ and vertical change of B was $1.04{\pm}1.96mm$ in prognathism group, horizontal change of Pog was $0.91{\pm}1.46mm$ and vertical change of Pog was $1.18{\pm}2.05mm$ in open bite group and horizontal change of Pog was $0.96{\pm}1.62mm$ and vertical change of Pog was $1.23{\pm}2.35mm$ in prognathism group (p>0.05) and there were statistical difference between open bite group and prognathism group in x-B, x-Pog, x-Gn, x-Me (p<0.05). Obwegeser II method is considered as one of the best operation when surgical correction of severe open bite or severe mandibular prognathism is needed.

• Information Systems Review
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• v.13 no.3
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• pp.165-183
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• 2011

IT organizations have been consistently required to change in order to cope with business and technological changes. However, the practical methodologies or guidelines about IT organization redesign are deficient. This research investigates IT organization's redesign methods and procedures focused on K public corporation which fundamentally redesigned IT organization recently. In K public corporation, to-be model of IT organization was designed with job analysis for IT organization redesign, task redesign was performed, and IT organization and personnel was assessed. 1) In task analysis, core activities are identified and 96 standard tasks are drawn. 2) with to-be organization design, IT support, IT delivery, IT operation teams and BuKyoung and Jeju teams were divided. 3) Previous job organization was restructured, IT organization personnel were finally confirmed through FTE and internal review. K public corporation strengthened IT planning task instead of reducing operational IT task, improved IT management process which was lower than other companies, and improved IT outsourcing management system and IT users' satisfactions. This research has practical implications for many companies which struggle with IT organization redesign method and process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.575-581
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• 2020

A colorless antistatic agent was prepared for use in antistatic films for liquid crystal displays (LCDs) requiring low surface resistance and high transmittance. Among various lithium-fluoro compounds and quaternary ammonium salts, antistatic materials were selected based on their electrical conductivity, and antistatic agents were prepared to measure the surface resistance. As a result, the material with high conductivity showed a relatively low surface resistance, i.e., relatively good antistatic performance. Based on the antistatic materials selected, the formulation ratio for producing the best antistatic agent was established through the experimental design method and the effects of each factor were analyzed. The higher the use of lithium- fluoro compounds as antistatic materials, the higher the ratio of oligomer use with multi-functional groups, and the smaller the surface resistance. The quaternary ammonium salts increased the antistatic performance of the lithium-fluoro compounds, but the effects of the amount used were not relatively large. After manufacturing the antistatic PET film, the properties of the antistatic film showed low surface resistance values (<10⁹ Ω/sq.), high permeability (>92%), low haze (<0.5%), and high whiteness (L^⁎>95). In addition, the antistatic film reliability was found to be excellent by showing a stable surface-resistance change rate of less than 10%, even under high temperature and high humidity conditions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.95-99
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• 2015

The IRR(internal rate of return) is often used by investors for the evaluation of engineering projects. Unfortunately, it has serial flaws: (1) multiple real-valued IRRs may arise; (2) complex-valued IRRs may arise; (3) the IRR is, in special cases, incompatible with the net present value (NPV) in accept/reject decisions. The efforts of management scientists and economists in providing a reliable project rate of return have generated over the decades an immense amount of contributions aiming to solve these shortcomings. Especially, multiple internal rate of returns (IRRs) have a fatal flaw when we decide to accep it or not. To solve it, some researchers came up with external rate of returns (ERRs) such as ARR (Average Rate of Return) or MIRR (MIRR, Modified Internal Rate of Return). ARR or MIRR. will also always yield the same decision for a engineering project consistent with the NPV criterion. The ERRs are to modify the procedure for computing the rate of return by making explicit and consistent assumptions about the interest rate at which intermediate receipts from projects may be invested. This reinvestment could be either in other projects or in the outside market. However, when we use traditional ERRs, a volume of capital investment is still unclear. Alternatively, the productive rate of return (PRR) can settle these problems. Generally, a rate of return is a profit on an investment over a period of time, expressed as a proportion of the original investment. The time period is typically the life of a project. The PRR is based on the full life of the engineering project. but has been annualised to project one year. And the PRR uses the effective investment instead of the original investment. This method requires that the cash flow of an engineering project must be separated into 'investment' and 'loss' to calculate the PRR value. In this paper, we proposed a tabulated form for easy calculation of the PRR by modifing the profit and loss statement, and the cash flow statement.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.355-362
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• 1999

Objective: This study was performed to compare the clinical response to controlled ovarian hyperstimulation (COH) of in vitro fertilization and embryo transfer (IVF-ET) according to the size of baseline ovarian cyst. Method: From February 1992 to March 1999, a retrospective analysis was done of 272 cases who underwent COH using mid-luteal phase long protocol of gonadotropin-releasing hormone agonist (GnRH-a) for IVF-ET. These cases were divided into four group; group 1 (n=63) had cysts with mean diameters between 20.0 and 29.0 mm on their baseline ultrasound on cycle day 3, group 2 (n=57, $30.0{\sim}49.0mm$), group 3 (n=68, >50.0 mm) and control group (n=84). Cases were excluded according to the following criteria; pure male factor infertility, the presence of only one ovary, high CA-125 level and previous endometriosis. Results: There were no statistically significant differences between cases with baseline ovarian cyst <50.0 mm in diameter and control group in any of the parameters. However, cases with baseline ovarian cyst>50.0 mm in mean diameter needed more amount of human menopausal gonadotropin (hMG), showed significantly lower estradiol ($E_2$) level, the number of follicle >15.0 mm on the day of human chorionic gonadotropin (hCG) administration, the number of oocytes retrieved, the number of mature oocytes, and pregnancy rate compared with control group. Conclusion: This study suggests that cases with baseline ovarian cyst <50.0 mm in diameter do not adversely impact on IVF-ET outcome. However, cases with baseline ovarian cyst >50.0 mm in diameter had adverse effects on various parameters. Therefore, to improve the outcome of IVF-ET in these cases, ovarian cyst aspiration prior to initiating COH may be required.