• The Journal of Korean Academy of Prosthodontics
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• v.49 no.2
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• pp.120-127
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• 2011

Purpose: The purpose of this study was to examine the effects of chromium chloride addition on coloration, mechanical property and microstructure of 3Y-TZP. Materials and methods: Chromium chloride was weighed as 0.06, 0.12, and 0.25 wt% and each measured amount was dissolved in alcohol. $ZrO_2$ powder was mixed with each of the individual slurry to prepare chromium doped zirconia specimen. The color, physical properties and microstructure were observed after the zirconia specimen were sintered at $1450^{\circ}C$. In order to evaluate the color, spectrophotometer was used to analyze the value of $L^*$, $C^*$, $a^*$ and $b^*$, after placing the specimen on a white plate, and measured according to the International Commission on Illumination (CIE) standard, Illuminant D65 and SCE system. The density was measured in the Archimedes method, while microstructures were evaluated by using the scanning electron microscopy (SEM) and XRD. Fracture toughness was calculated Vickers indentation method and indentation size was measured by using the optical microscope. The data were analyzed with 1-way ANOVA test (${\alpha}$ = 0.05). The Tukey multiple comparison test was used for post hocanalysis. Results: 1. Chromium chloride rendered zirconia a brownish color. While chromium chloride content was increased, the color of zirconia was changed from brownish to brownish-red. 2. Chromium chloride content was increased; density of the specimen was decreased. 3. More chromium chloride in the ratio showed increase size of grains. 4. But the addition of chromium chloride did not affect the crystal phase of zirconia, and all specimens showed tetragonal phase. 5. The chromium chloride in zirconia did not showed statistically significant difference in fracture toughness, but addition of 0.25 wt% showed a statistically significant difference (P<.05). Conclusion: Based on the above results, this study suggests that chromium chlorides can make colored zirconia while adding in a liquid form. The new colored zirconia showed a slight difference in color to that of the natural tooth, nevertheless this material can be used as an all ceramic core material.

• Journal of Korean Academy of Nursing
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• v.10 no.2
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• pp.73-85
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• 1980

The purpose of this study was to investigate the compliance behavior of hypertensive patients in light of their health belief model that explains an individual's compliance with health maintenance or getting well. Although there are many effective regimens and treatments for hypertension nowadays. the most important point to be taken to consideration in their behavioral aspect is their compliance with regard to the control of body weight. eating habits as to salt and cholesterol intake. stresses. activity patterns and smoking as related to their life style. The important reasons for the failure in the control of hypertensive patients are the complexity of regimens to be complied to. irregular medication and the life long restrictions in their own life style. The compliance of patients to medical regimens and rocommendations or failure to do so is an essential factor. Accordingly. the degree of the patient's compliance is an important determinant as to the success or failure of hypertension control. The subjects for this study were 187 hypertensive patients selected from admitted and out patients of the medical department at seven University Hospitals in Seoul. Data was collected from Dec. 1, 1979 to Feb. 15, 1980 using the questionaire method and was analysed by the use of means. standard deviations, coefficient of correlations, analysis of variance and multiple regression analysis. The results obtained are as follows A. Of the seven independent variables in light of health belief model. benefit. barrier and severity are closely related to patient's compliance behavior. Therefore these variables could be used as determinants to predict and modify the hypertensive behavior. 1. Benefit is the most important and significant of the variables for explaining the dependent variables. It accounts for the highest variance of patient's compliance. (23.62%) 2. Then taking the former together with barrier. the variance of compliance showed on increase. (26.59%) 3. And with the addition of severity to the first two. the variance of compliance was also increased. (28.l2 %) B. Except for susceptibility all the independent variables such as severity. benefit, knowledge. motivation and barrier are correlated to dependent variable compliance. C. Sex. marital status and religion appeared to have significant influence on the dependent variables. Therefore one could conclude that the more the patients are aware that hypertension is a threat to health. the more they understand the benefit of taking actions to prevent such a threat. and the less they perceive any barrier when taking action. the more compliant they become in following medical regimens and recommendations. Age. marital status and religion played a significant influence to their compliance. Accordingly. the selected structural variables and demographic variables which have influenced sick role behavior of the hypertensive patient must be integrated to teaching and counselling programs for better hypertension control.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.324-333
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• 2006

This study was designed to investigate the effect of bone demineralization and tibia lead on blood lead in retired lead workers. Two hundred thirty five(126 females and 109 males) retired lead workers who worked in 4 different lead factories and 101 non-occupationally lead exposed subjects(51 females and 51 males) were recruited from March 2004 to October 2004. Bone mineral density(BMD) was measured at left calcaneous bone area by broadband ultrasound attenuation(BUA) method with QUS-2(Metra Biosystems Inc, USA). The BUA value transformed into T-score by WHO standard conversion criteria. Tibia bone lead was measured for skeletal bone lead with K-xray fluorescence(K-XRF) and blood lead was analyzed with flameless atomic spectrophotometer. Hemoglobin, hematocrit, serum calcium and iron were also analyzed. In addition, information for smoking and drinking status and basic personal data such as age, gender and lead exposure were also collected using questionnaire inquiry. Blood lead was correlated with tibia lead (r=0.664) and these two variables were negatively correlated with BMD in bivariate analysis. BMD showed significant main effect on the change of blood lead independent to tibia lead without any effect modification of age or gender; the one T-score unit decrease of mineral bone density made $0.43{\mu}g/dl$ increase of blood lead. On the other hand, tibia lead showed effect modification with gender on blood lead; the slope of tibia lead on blood lead in male was steeper than in female and crossed at around zero of tibia lead. In the multiple regression analysis of blood lead and tibia lead on BMD after adjustment of related covariates, only blood lead showed statistically significant effect on BMD. This study confirmed that BMD and blood lead were significantly associated. To verify the causal association of BMD on blood lead and vice versa, further longitudinal studies are needed.

• The Journal of Advanced Prosthodontics
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• v.15 no.6
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• pp.281-289
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• 2023

PURPOSE. This study aimed to predict the positional coordinates of incisor points from the scan data of conventional complete dentures and verify their accuracy. MATERIALS AND METHODS. The standard triangulated language (STL) data of the scanned 100 pairs of complete upper and lower dentures were imported into the computer-aided design software from which the position coordinates of the points corresponding to each landmark of the jaw were obtained. The x, y, and z coordinates of the incisor point (X_P, Y_P, and Z_P) were obtained from the maxillary and mandibular landmark coordinates using regression or calculation formulas, and the accuracy was verified to determine the deviation between the measured and predicted coordinate values. Y_P was obtained in two ways using the hamularincisive-papilla plane (HIP) and facial measurements. Multiple regression analysis was used to predict Z_P. The root mean squared error (RMSE) values were used to verify the accuracy of the X_P and Y_P. The RMSE value was obtained after crossvalidation using the remaining 30 cases of denture STL data to verify the accuracy of Z_P. RESULTS. The RMSE was 2.22 for predicting X_P. When predicting Y_P, the RMSE of the method using the HIP plane and facial measurements was 3.18 and 0.73, respectively. Cross-validation revealed the RMSE to be 1.53. CONCLUSION. Y_P and Z_P could be predicted from anatomical landmarks of the maxillary and mandibular edentulous jaw, suggesting that Y_P could be predicted with better accuracy with the addition of the position of the lower border of the upper lip.

• Asia pacific journal of information systems
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• v.19 no.2
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• pp.139-155
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• 2009

For the last few decades, many studies have tried to explore and unveil venture companies' success factors and unique features in order to identify the sources of such companies' competitive advantages over their rivals. Such venture companies have shown tendency to give high returns for investors generally making the best use of information technology. For this reason, many venture companies are keen on attracting avid investors' attention. Investors generally make their investment decisions by carefully examining the evaluation criteria of the alternatives. To them, credit rating information provided by international rating agencies, such as Standard and Poor's, Moody's and Fitch is crucial source as to such pivotal concerns as companies stability, growth, and risk status. But these types of information are generated only for the companies issuing corporate bonds, not venture companies. Therefore, this study proposes a method for evaluating venture businesses by presenting our recent empirical results using financial data of Korean venture companies listed on KOSDAQ in Korea exchange. In addition, this paper used multi-class SVM for the prediction of DEA-based efficiency rating for venture businesses, which was derived from our proposed method. Our approach sheds light on ways to locate efficient companies generating high level of profits. Above all, in determining effective ways to evaluate a venture firm's efficiency, it is important to understand the major contributing factors of such efficiency. Therefore, this paper is constructed on the basis of following two ideas to classify which companies are more efficient venture companies: i) making DEA based multi-class rating for sample companies and ii) developing multi-class SVM-based efficiency prediction model for classifying all companies. First, the Data Envelopment Analysis(DEA) is a non-parametric multiple input-output efficiency technique that measures the relative efficiency of decision making units(DMUs) using a linear programming based model. It is non-parametric because it requires no assumption on the shape or parameters of the underlying production function. DEA has been already widely applied for evaluating the relative efficiency of DMUs. Recently, a number of DEA based studies have evaluated the efficiency of various types of companies, such as internet companies and venture companies. It has been also applied to corporate credit ratings. In this study we utilized DEA for sorting venture companies by efficiency based ratings. The Support Vector Machine(SVM), on the other hand, is a popular technique for solving data classification problems. In this paper, we employed SVM to classify the efficiency ratings in IT venture companies according to the results of DEA. The SVM method was first developed by Vapnik (1995). As one of many machine learning techniques, SVM is based on a statistical theory. Thus far, the method has shown good performances especially in generalizing capacity in classification tasks, resulting in numerous applications in many areas of business, SVM is basically the algorithm that finds the maximum margin hyperplane, which is the maximum separation between classes. According to this method, support vectors are the closest to the maximum margin hyperplane. If it is impossible to classify, we can use the kernel function. In the case of nonlinear class boundaries, we can transform the inputs into a high-dimensional feature space, This is the original input space and is mapped into a high-dimensional dot-product space. Many studies applied SVM to the prediction of bankruptcy, the forecast a financial time series, and the problem of estimating credit rating, In this study we employed SVM for developing data mining-based efficiency prediction model. We used the Gaussian radial function as a kernel function of SVM. In multi-class SVM, we adopted one-against-one approach between binary classification method and two all-together methods, proposed by Weston and Watkins(1999) and Crammer and Singer(2000), respectively. In this research, we used corporate information of 154 companies listed on KOSDAQ market in Korea exchange. We obtained companies' financial information of 2005 from the KIS(Korea Information Service, Inc.). Using this data, we made multi-class rating with DEA efficiency and built multi-class prediction model based data mining. Among three manners of multi-classification, the hit ratio of the Weston and Watkins method is the best in the test data set. In multi classification problems as efficiency ratings of venture business, it is very useful for investors to know the class with errors, one class difference, when it is difficult to find out the accurate class in the actual market. So we presented accuracy results within 1-class errors, and the Weston and Watkins method showed 85.7% accuracy in our test samples. We conclude that the DEA based multi-class approach in venture business generates more information than the binary classification problem, notwithstanding its efficiency level. We believe this model can help investors in decision making as it provides a reliably tool to evaluate venture companies in the financial domain. For the future research, we perceive the need to enhance such areas as the variable selection process, the parameter selection of kernel function, the generalization, and the sample size of multi-class.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1687-1698
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• 2021

This study is to produce multiple layers of liposomes in a supercritical state and encapsulates active ingredients in order to stably encapsulate thermodynamically unstable active ingredients. In order to form a liposome in a supercritical state, a mixed surfactant development including vegetable-derived hydrogenated phosphatidyl choline and their delivative, hydrogenated sucrose distearate was synthesized as high purity. It describes a manufacturing method of injecting liquid carbon dioxide into a reactor to create a supercritical state and stirring to produce a giant liposome, and adding and loading genistein and quercetin. The HLB of the mixed lipid complex (SC-Lipid Complex) was 12.50, and multiple layers of liposome vesicles were formed even at very low concentrations. This surfactant had a specific odor with a pale yellow flake, the specific gravity was 0.972, and the acid value was 0.12, indicating that it was synthesized with high purity. As a result of the emulsifying capacity experiment using 20 wt% capric/capric triglyceride and triethylhexanoin using SC-Lipid Complex, it was found to have 96.2% emulsifying power. SC LIPOSOME GENISTEIN was confirmed that a multi-layer liposome vesicle was formed through a transmission electron microscope (Cryo-TEM) for the supercritical liposome encapsulated with genistein. The primary liposome particle size in which genistein was encapsulated was 253.9 nm, and the secondary capsule size was 18.2 ㎛. Using genistein as the standard substance, the encapsulation efficiency of supercritical liposomes was 99.5%, and general liposomes were found to have an efficiency of 93.6%. In addition, the antioxidant activity experiment in which quercetin was sealed was confirmed by the DPPH method, and it was found that the supercritical liposome significantly maintained excellent antioxidant activity. In this study, thermodynamically unstable raw materials were sealed into liposomes without organic solvents in a supercritical state. Based on these results, it is expected that it can be applied to various forms such as highly functional skincare cosmetics, makeup cosmetics, and scalp protection cosmetics.

• Korean Journal of Occupational Health Nursing
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• v.6 no.2
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• pp.110-127
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• 1997

The aim of this study is to present the basic datum for the promotion of effectiveness and improvement of nursery tasks, by grasping the situation of operating room nurses tasks and the degree of their fatigue. For these researches, 70 nurses out of the operating rooms of 3 university-affiliated hospitals-two in Seoul and one in Pusan, were chosen at random by a non-probability sampling method. These researches were done from April 14 to April 26 in 1997 by questionairing method. The questionaire was composed of 30 items, which asks the examinees of their physical, mental, and neurosensory symptoms, with 10 items respectively. The reliability of the research instrument was turned out very high with Cronbach's ${\alpha}=.9376$. The datum were electronically processed using Statistics Program for Social Sciences(SPSS). The analysis of datum in this study has a general character, in which the demosociological character and the special ex-officio character was calculated by frequency and percentage. The situation of tasks in operating rooms was calculated by frequency and percentage. The fatigue of operating room nurses was calculated by average and standard deviation. To compare the fatigue with regard to the character of operating room nurse's tasks, t-test and F-test(ANOVA) were used after the character of variations, and the variations at the level of P<.05 which might have some meaning was verified after the fact with Duncan's Multiple Range(DMR). The results of this research are as follows : 1) The nurses working in operating rooms show their fatigue in three fields-in Group I physical symptoms 3.28, in Group III neurosensory symptoms 2.85, and in Group II mental symptoms 2.73, which shows I Dominant type (general type). 2) They complain, in Group I they are "feeling the heavy legs," 3.28 and in Group II they "occasionally forget soon what to do," 3.09. and in Group III, they "feel lumbago," 3.47, which is the highest rate of the three. The highest rate results from the character of their tasks, in which they have to move rapidly the heavy appliances and do their jobs standing many hours, especially wearing heavy radiation protector. 3) As to transportation, subway using group feel the greatest fatigue, 3.18(F=4.315, P=.008). 4) As to department, nurses in the orthopedic's surgery part feel the greatest fatigue, 3.26(F=2.040, P=.050). 5) As to the change of physical symptoms, the group answering that they found physical abnormality after working in operating rooms show the greatest fatigue, 3.12(t=-3.13, P=.003). 6) At to the general circumstances, the group answering that they receive insufficient consideration on their physical abnormality in their department, show the greatest fatigue, 3.10(F=3.200, P=0.47). 7) As to the relation with superior officers, the group answering that their superior officer has an impetuous temperament, show great fatigue, 3.11(F=4.855, P=.011). 8) As to the time of feeling fatigue, the fatigue reaches the highest point 1~2 hours after operations, 3.04(F=2.703, P=.046). 9) When they feel fatigue after scrub nurse duties, they feel the greatest fatigue 2 hours after the duties, 3.09( F=2.841, P=.038). 10) As to the operation instruments, when they use complex instruments borrowing from the outside in addition to the basic instruments, their fatigue becomes the greatest, 3.09(F=7.831, P=.000). 11) As to the kind of operation, when they participate in orthopedic's surgery operations, they feel the greatest fatigue, 3.18(F=4.362, P=.000). With the above results, it is proved that the degree of operating room nurses' fatigue is considerably high. So it may be concluded that the measure for lessening the fatigue should be find immediately, not on the level of personal matters but on the level of hospital nursing administration.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.283-288
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• 2011

This study was conducted to study the environment effects on live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score, which are the carcass traits of Hanwoo, based on the estimates and all the possible regression for the selection of variable and significance test for 231,382 heads that underwent the carcass measurements. The average and standard deviation for the live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score were 654.79${\pm}$91.61 kg, 362.30${\pm}$67.15 kg, 59.52${\pm}$0.03%, 81.79${\pm}$12.21 $cm^2$, 11.39${\pm}$5.40 mm, 4.38${\pm}$2.29, respectively. The live weight, carcass weight, dressing percentage, eye muscle area, backfat thickness, and marbling score for cow were 532.79${\pm}$78.38 kg, 313.40${\pm}$44.90 kg, 56.50${\pm}$0.03%, 75.24${\pm}$10.69 $cm^2$, 11.82${\pm}$5.10 mm, 4.30${\pm}$2.06, respectively, while for bull were 619.74${\pm}$93.27 kg, 376.89${\pm}$48.62 kg, 58.61${\pm}$0.02%, 85.61${\pm}$10.46 $cm^2$, 5.64${\pm}$2.71 mm, 1.41${\pm}$0.83, respectively, and for steer were 681.78${\pm}$70.72 kg, 415.23${\pm}$49.43 kg, 60.19${\pm}$0.02%, 88.29${\pm}$10.27 $cm^2$, 12.71${\pm}$5.23 mm, 5.42${\pm}$1.99, respectively. In the environmental variables selection based on the variables selection method, the examination by carcass traits suggested that the most appropriate model could be determined when five variables were selected for the live weight, carcass weight, dressing percentage, eye muscle area, and four variables for backfat thickness, and marbling score. When they were considered at a time altogether based on multiple traits, it was deemed to be desirable to insert all five variables into the variables for analysis. In addition, high significance was found by carcass traits.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.7 no.1
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• pp.29-50
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• 2001

This research have been made to define how the IADL (Instrumental Activity of Daily Living) performance and the subjective health index of the Aged are affected by their residential circumstance, gender and age, and how deeply these two factors are related and interact. For the period of June 1 to July 31, 2000, we had conducted a questionnaire and direct interview with 693 persons over age sixty-five (65) in Daejon and in other adjacent area, grouping into three different residential types The Aged living at home, The Aged living at welfare facilities and The Aged living alone, and studied on how the IADL performance and the subjective health index of the Aged are influenced and interact as per their characteristics, daily activity and mentality. We had analyzed all the data obtained through this research by the method of : - analysis of frequency as per specific factors by SPSS 1O.0/PC+, - $x^2$ test, - t-test, - ANOVA, - multiple regression analysis by factors. The research concludes followings : a. It appears that the three (3) factors such as gender, age and residential circumstance of the Aged deeply affect the IADL performance and subjective health index of the Aged. (p<0.01) b. With regard to IADL performance of the Aged by the gender, it was analyzed that the female-Aged gains 23.8 point on average, which shows the performance of the female-Aged is less independent. (p<0.01). In addition, it was also found that the IADL performance is becoming less and less independent following their age increasing. In analyzing IADL performance by the residential type, it appears that the Aged living at welfare facilities gains the lowest 21.5 points and is least independent. It was also found that the Aged living at welfare facilities need some assistances from others for their performing IADL. (20-24 point) (p<0.001) c. With regard to the subjective health index of the all-Aged participated in this research, the analysis indicates 8.8 point and this is considered as a point of general standard (7-10 point). In analyzing this index by the gender, the female-Aged gains only 8.6 point which explains a lot of female-Aged consider they are not really healthy. (p<0.001) In analyzing this index by the residential type, the Aged living at welfare facilities and the Aged living alone gain the comparatively lower point, - respectively 8.4 point for the Aged living at welfare facilities and 8.8 point for the Aged living alone. The Aged living at these two residential types express they are obviously in a bad situation of health. (p<0.001) d. With regard to the factors affecting the IADL performance and the subjective health index of the Aged, it was analyzed that the IADL performance can largely be affected by the factors such as depression, frequency of going-out and age rising, and that the subject health index can also deeply be affected by depression, pain and by how much they are satisfied with their current living conditions. e. It was analyzed that the interacting between the IADL performance and the subjective health index is not that strong but even weak. As a result, we were able to conclude that the IADL performance is less independent in case of the female-Aged, the Aged living at welfare facilities, and following the age rising. As for the subjective health state the Aged themselves are aware of, we concluded that the female-Aged, the Aged living at welfare facilities and the Aged living alone, are more critical about their health. From this research, we were able to realize that, when the OMT (Orthopedic Manual Therapy) needed, the physical therapists are really required to have a correct and cautious understanding of the situation in which the aged persons are, and take care of them with more concerns and more improved treatment.

• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.