• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.1-7
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• 2023

Durability was evaluated by performing a full-scale vertical load fatigue test and a wheel load performance test on the HRS, which reduces the replacement time of the existing expansion joint and improves serviceability to allow partial replacement by lane. As a result of the vertical load fatigue test, the maximum stress of the rail-type expansion joint is 170 MPa, which is about 47.8% of the yield strength of the HRS expansion joint rail 355 MPa. The vertical load fatigue test of the HRS expansion joint with improved serviceability set the size and load of the load plate according to the road bridge design standards, did not show any fracture behavior in the vertical load fatigue test and the wheel load performance test 2 million times, and its durability and safety were verified.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.6
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• pp.460-472
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• 2023

This study was conducted based on the case of an accident (excessive deformation) that occurred during the hydraulic test of a shipboard tank manufactured in accordance with the design regulations. Over-pressure phenomenon was noted as the main cause of accidents in the process of testing tanks without physical damage, which can be found in external factors such as cross-sectional difference between inlet pipe and air pipe and higher water filling rate than the recommended one. The main goal of this paper is to establish a safe water filling rate according to the range of sectional area ratio(SAR) reduced below the regulations for each test situation. The simulation was conducted in accordance with the hydraulic test procedure specified in the Ship Safety Act, and the main situation was divided into two types: filling the tank with water and increasing the water head to the test pressure. The structural safety evaluation of the pressure generated inside the tank and the effect on the structure during the test was reviewed according to the SAR range. Based on the results, guidelines for the optimal filling rate applicable according to SAR during the hydraulic test were presented for the shipboard tanks used in this study.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.788-797
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• 2023

In this paper, we introduced a test environment to test a vision-aided navigation system, as an alternative navigation system when global positioning system (GPS) is unavailable, for vertical take-off and landing (VTOL) unmanned aerial system. It is efficient to use a virtual environment to test and evaluate the vision-aided navigation system under development, but currently no suitable equipment has been developed in Korea. Thus, the proposed test environment is developed to evaluate the performance of the navigation system by generating input signal modeling and simulating operation environment of the system, and by monitoring output signal. This paper comprehensively describes research procedure from derivation of requirements specifications to hardware/software design according to the requirements, and production of the test environment. This test environment was used for evaluating the vision-aided navigation algorithm which we are developing, and conducting simulation based pre-flight tests.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.39-51
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• 2023

The bearing capacity of the prebored pile has been studied by many researchers. However, The bearing capacity of the prebored pile has been studied by many researchers. However, comparative studies between design data and pile load test data on the load sharing ratio and the settlement were insignificant. Therefore, the design data and the static load test results were compared for the prebored open-end steel piles. In the compressive static pile load test, the load sharing ratios of the base resistance and the shaft resistance were 13%~40% and 60%~87%, respectively and the settlements were measured 2.2mm~4.7mm. In the current bearing capacity calculation formula, the base resistance was shared between 54% and 75%, and the shaft resistance was shared between 25% and 46% and the settlements were calculated about 19.8mm~23.6mm. The settlement in the current bearing capacity calculation formula was 321% to 776% (average : 445%) larger than the settlement in the result of load test. When the settlement were calculated using the load sharing ratio in the pile load tests, it was 137% to 525% larger than the test settlement, and it was as large as 204% on average. It was confirmed that an appropriate evaluation of the load sharing ratio had an important effect on the calculation of pile settlement.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.4
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• pp.211-222
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• 2016

Reinforced concrete shear walls with deficient reinforcement details are tested under cyclic loading. The deficiency of reinforcement details includes insufficient splice length in U-stirrups at the ends of horizontal reinforcement and boundary column dowel bars found in existing low- to mid-rise Korean buildings designed non-seismically. Three test specimens have rectangular, babel and flanged sections, respectively. Flexure- and shear-controlled models for reinforced concrete shear walls specified in ASCE/SEI 41-13 are compared with the flexural and shear components of force-displacement relation extracted separately from the top displacement of the specimen based on the displacement data measured at diverse locations. Modification of the shear wall models in ASCE/SEI 41-13 is proposed in order to account for the effect of bar slip, cracking loads in flexure and shear. The proposed modification shows better approximation of the test results compared to the original models.

• Journal of Fashion Business
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• v.10 no.1
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• pp.41-57
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• 2006

The purpose of this study were to provide dress forms and men's jacket blocks based on the analysis of their somatotype. As the result of the previous research, based on 1290 males of 20 to 54 year-old, the shapes of adult male were 20 and each body shape was classified by size factor, height and chest girth and master size was selected considering appearance frequency. Somatotype YS(master size: height 170cm, chest girth 91cm) and HD1(master size: height 170cm, chest girth 94cm) were selected to develop dress forms and men's jacket block in the study. The procedure and results were follows; 1. The dress forms of somatotype YS and HD1 were provide base on means of 61 body measurements and cross sections of shoulder, chest, waist, hip of subjects belong to each somatotype. 2. New men's jacket blocks of somatotype YS and HD1 were developed based on the body surface extracted by draping and the result of comparative investigation on the conventional jacket patterns by wearing test. Also the drafting methods of new men's jacket blocks were provided. 3. Wearing test by the sensory evaluation showed that the developed jacket blocks were estimated more highly than existing patterns.

• Journal of Korean Biological Nursing Science
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• v.11 no.1
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• pp.51-58
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• 2009

Purpose: It is to verify learning effect of the instructional media on anatomy classes at a nursing college and to develop an alternative instructional media instead of cadaver. Method: Four groups pretest-posttest experimental design were used. One hundred twenty students who attended an Anatomy lecture in September, 2009 were selected After attending the anatomy lecture, the subjects were divided into four group (30 for each group) conveniently. The heart anatomy knowledge level were measured by a self evaluation questionnaire and quiz before and after a different instructional media being applied for each group including making heart shape using colored clay, taking picture of a real heart, sketching the heart model with color pencil and drawing heart presented in the anatomy textbook. Data was analyzed by t-test, ANNOVA test using the SPSS/PC WIN 12 version. Result: A statistically significant differences in the level of heart anatomy knowledge acquirement was noted after four different instructional media being applied, and four different instructional media was effective to the anatomy practice education. However, no difference in statistical post test results was noted among the four groups. Conclusion: It is recommended that further comparative studies on the learning effect between human cadaver practice and different instructional media is necessary.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.5
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• pp.778-788
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• 2015

This study evaluated the characteristics and sensibility of work clothes materials developed that took into account the work environment of major industrial settings, for which a selection was made according to spring/autumn use and winter use. The physical properties of the existing and test weaving of the work clothes materials were compared after the test weaving of work clothes materials through material design, which altered the yarn count, composition, weave and density of material. To evaluate sensibility of work clothes materials subjectively, seven ranks' semantic differential scale questions were developed with polar adjective pairs. The test weaving of work clothes materials showed improved performance (such as tensile strength, dimensional change, water vapor permeability, and color fastness) compared to the existing materials. The common factor analysis indicated that the explanatory power of the cumulative variance for the spring/autumn use and winter use was 71.19% and 69.53%, respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.82-89
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• 2006

This paper describes the development results of electrohydraulic actuation system which performs the attitude and trajectory control of pitch and yaw motion using thrust vector control for high altitude launching vehicle operated in high vacuum environment (altitude higher than 300 km). As compared with electrohydraulic actuation system for low altitude launch vehicle which operated under altitude of stratosphere, the intensified development requirements, newly adopted design and manufacturing technologies, newly developed test equipments and test results are summarized in this paper. The development test and evaluation of actuation system were successfully accomplished. The developed actuation system will be installed on KSLV-I after finishing verification of interface and integration compatibility with related other systems.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.44-53
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• 2010

Recently, the external prestressed concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with unbonded tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. By this reason, the ultimate stress of external tendon is smaller than that of bonded tendon or internal unbonded tendon. However, in the domestic and abroad code, the equation of ultimate stress of external tendon is not suggested yet, and the equation of ultimate stress of internal unbonded tendon is used instead of that of external tendon. Therefore, in this paper, after effective variables of ultimate stress of external tendon were analyzed, the analytical equation of ultimate stress of external tendon was proposed. And the reasonable coefficients were proposed by statistical work of test results of 25 beam with external tendon. Finally, the practical proposed equation of ultimate stress of external tendon was proposed with analytical and statistical model. The equation of ACI-318 and AASHTO 1994 were not matched with test results and had no correlations, and the proposed equation was well matched with test results. So the proposed equation in this paper will be a effective basis for the evaluation of external tendons in analysis and design.