• International Journal of Precision Engineering and Manufacturing
• /
• 제8권3호
• /
• pp.50-53
• /
• 2007

Improving the reliability or long-term dependability of a system requires a different approach from the previous emphasis on short-term concerns. The purpose of this paper is to present a reliability evaluation method for an oil cooler intended for high-precision machining centers. The oil cooler system in question is a cooling device that minimizes the deformation caused from the heat generated by driving devices. This system is used for machine tools and semiconductor equipment. We predicted the reliability of the system based on the failure rate database and conducted the reliability test using a test-bed to evaluate the life of the oil cooler. The results provided an indication of the reliability of the system in terms of the failure rate and the MTBF of the oil cooler system and its components, as well as a distribution of the failure mode. These results will help increase the reliability of oil cooler systems. The evaluation method can also be used to determine the reliability of other machinery products.

• 한국자동차공학회논문집
• /
• 제8권6호
• /
• pp.279-286
• /
• 2000

The stud bolts tend to degrade faster by high temperature(over 45$0^{\circ}C$). Therefore, replacement cycle inspection of stud bolts were carried out various method such as ultrasonic test(UT), magnetic test(MT), wobble test, visual test and hardness test. Especially, wobble test method has been applied to determine replacement evaluation criteria of stud bolt after long time operation. We applied three different methods on the three site and the obtained data are compared with the results from the evaluation methods. From the results, the replacement criteria for stud bolts under high temperature in power plants are proposed.

• 대한간호학회지
• /
• 제14권2호
• /
• pp.5-11
• /
• 1984

The main purpose of this study were; to determine the reliability and validity of evaluation tool administered to the nursing student in nursing management practice,；to identify the effective evaluation method of nursing student in nursing management practice. The subjects were 46 senior nursing students at Department of Nursing, College of Medicine, Seoul National University in 1983. The evaluation tool was analyzed according to evaluation method; self-evaluation. and head nurse evaluation. Also individual item of evaluation tool was analyzed by item analysis in order to determine the evaluation area, and appropriateness of the test item used. A Summary of the results is as follows; 1. The reliability and validity of evaluation tool were relatively high both in self-evaluation and head nurse evaluation. 2. In comparison of mean scores, there is no significant difference between head nurse evaluation and self-evaluation. 3. The nursing management activities which have the correlation of self-evaluation and head nurse evaluation were in the activity of interpersonal relation, independent activity and implementing nursing process. In general nursing practice and unit management activity, there was no correlation of self-evaluation and head nurse evaluation.

• 한국정밀공학회지
• /
• 제20권5호
• /
• pp.140-147
• /
• 2003

As the huge energy transfer systems like as nuclear power plant and steam power plant are operated for a long time at a high temperature, mechanical properties are changed and ductile-brittle transition temperature is raised by degradation. So it is required to estimate degradation in order to assess the safety, remaining life and further operation parameters. The sub-sized specimen test method using surveillance specimen was developed for evaluating the integrity of metallic components. In this study, we would like to present the evaluation technique of the ductile-brittle transition temperature by the sub-sized specimen test. The four classes of the thermally aged 1Cr-1Mo-0.25V specimens were prepared using an artificially accelerated aging method. The tensile test and fracture toughness test were performed. The results of the fracture toughness tests using the sub-sized specimens were compared with the evaluation technique of the ductile-brittle transition temperature.

• Structural Engineering and Mechanics
• /
• 제24권1호
• /
• pp.91-105
• /
• 2006

In this paper, post-earthquake capacity evaluation method of reinforced concrete buildings was studied. Substructure pseudo-dynamic test and static loading test of first story column in a four-story R/C building was carried out in order to investigate the validity of the evaluation method proposed in the Damage Assessment Guideline (JBDPA 2001). In pseudo-dynamic test, different levels of damage were induced in the specimens by pre-loading, and input levels of seismic motion, at which the specimens reached to the ultimate stage, were examined. From the experimental result, no significant difference in damage levels such as residual crack width between the specimens under static and pseudo-dynamic loading was found. It is shown that the seismic capacity reduction factors ${\eta}$ can provide a reasonable estimation of post-earthquake seismic capacity of R/C buildings suffered earthquakes.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집A
• /
• pp.579-584
• /
• 2001

As the huge energy transfer systems like as nuclear power plant and steam power plant are operated for a long time, mechanical properties are changed and ductile-brittle transition temperature is raised by degradation. So it is required to estimate degradation in order to assess the safety, remaining life, and further operation parameters. The sub-sized specimen test method using surveillance specimen was developed for evaluating the integrity of metallic components. In this study, we would like to present the evaluation technique of the ductile-brittle transition temperature by the sub-sired specimen test. The four classes of the thermally aged 1Cr-1Mo-0.25V specimens were prepared using an artificially accelerated aging method. The tensile test and fracture toughness test were performed. The results of the fracture toughness tests using the sub-sized specimens were compared with the evaluation technique of the ductile-brittle transition temperature.

• 한국철도학회논문집
• /
• 제6권2호
• /
• pp.114-121
• /
• 2003

In this paper, a new evaluation system was developed for ride comfort test and vibration level test on railway vehicles. These tests are carried out by applying different equipments and test procedures before now. But this developed system is capable of ride comfort test and vibration test by a single integrated system. Also, the evaluation algorithm for the ride comfort was compared and verified by simulation results with VAMPIRE software. With this developed system, the comfort in a passenger coach and the vibration in a freight car were verified by the results in field test.

• Human Ecology Research
• /
• 제60권4호
• /
• pp.625-643
• /
• 2022

The purpose of this study was to explore the trends and core keywords of the secondary school home economics teacher selection test using content analysis and text network analysis. The sample comprised texts of the secondary school home economics teacher 1st selection test for the 2017-2022 school years. Determination of frequency of occurrence, generation of word clouds, centrality analysis, and topic modeling were performed using NetMiner 4.4. The key results were as follows. First, content analysis revealed that the number of questions and scores for each subject (field) has remained constant since 2020, unlike before 2020. In terms of subjects, most questions focused on 'theory of home economics education', and among the evaluation content elements, the highest percentage of questions asked was for 'home economics teaching·learning methods and practice'. Second, the network of the secondary school home economics teacher selection test covering the 2017-2022 school years has an extremely weak density. For the 2017-2019 school years, 'learning', 'evaluation', 'instruction', and 'method' appeared as important keywords, and 7 topics were extracted. For the 2020-2022 school years, 'evaluation', 'class', 'learning', 'cycle', and 'model' were influential keywords, and five topics were extracted. This study is meaningful in that it attempted a new research method combining content analysis and text network analysis and prepared basic data for the revision of the evaluation area and evaluation content elements of the secondary school home economics teacher selection test.

• 대한가정학회지
• /
• 제27권4호
• /
• pp.41-50
• /
• 1989

Cobaltous Chloride method has been known as a sufficiently good test methodolgy for the dynamic moisture transfer through textile fabrics. In the current study, Cobaltous Chloride method was adopted and modified to test dynamic moisture transfer in clothing under actual wearing conditions. It was possible to test the significant difference between fabric types by controlling the position of CoCl2 impregnated swatch (LD type), time scale of the moisture transfer (within 10 mins), experimental design (split plot desing) and other miscellaneous experimental techniques. As results, it was concluded that Cobaltous Chloried method is a satisfactory screening test to predict moisture related comfort properties of clothing as won.

• 공학교육연구
• /
• 제16권4호
• /
• pp.15-20
• /
• 2013

The result of the English test for freshmen showed wide difference in the ability of students, which means the graded class is strongly required. This paper describes the case study about the graded English class that was carried out for the freshman. Every freshman must take an English placement test from problems bank and were classified according to the result of the test. In order to resolve the dissatisfaction of the high level students, the statutes of my university for credit were modified. In order to analyze the effect of the graded class, evaluation test using similar problems was carried out at the end of the semester. The effect of the graded class was analyzed by using the paired samples t-test method and there was a meaningful performance improvement at the average score. Additional improvements in the method of classification and credit granted were made by analyzing the results of the evaluation test and survey.