• Title/Summary/Keyword: quasi-experiment research

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Mechanical Properties of External Thermal Insulation Composite System with Quasi-Non-Combustible Performance (준불연 외단열시스템의 역학적 특성에 관한 연구)

  • Choi, Ki-Sun;Ha, Soo-Kyung;Oh, Keun-Yeong;Park, Keum-Sung;Ryu, Hwa-Sung
    • Journal of the Korea Institute of Building Construction
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    • v.21 no.5
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    • pp.507-518
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    • 2021
  • The application of an adhesive calcium carbonate-based hybrid insulation board with quasi-combustibility in the external thermal insulation composite system(ETICS) ensures effective thermal performance and fire safety. This study aimed to conduct a mechanical test of the quasi-non-combustible hybrid insulation board as well as its constituent materials to obtain the basic data for the structural design of the adhesive ETICS. Test specimens were fabricated based on domestic and foreign test standards to examine and evaluate their tensile, compressive, flexural, and shear strengths. The strength characteristics of the quasi-non-combustible hybrid insulation board were identified from the test results, which verified that the minimum required physical properties suggested by the current KS M ISO 4898 were met. Furthermore, the quasi-non-combustible ETICS used in this study was found to be suitable for use as an external insulation system for walls unless subjected to continuous gravity load, such as a heavy exterior finish.

Research on Transferring the National Height System to the Island

  • Liu, Yanxiong;Zhou, Xinghua;Peng, Lin;Wu, Yongtong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.425-427
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    • 2006
  • It is quite difficult to transfer the National Height System 1985 to the island in China. In the study, one feasible and alternative way, which measures synchronally the tide variation at the island and the coast , is firstly introduced. Then, a new method is proposed. This new method combines GPS technique and Quasi-Geoid Determination technique (GQGD). It needs gravity data, GPS data, leveling data and DEM data, together with complex calculation method and the Earth gravity model. After describing the mathematical model and presenting the calculational steps, one experiment has been shown that this method is valid and can achieve accuracy up to 5 cm for the normal height, compared with the results both from the tidal observation and height approximation. Some suggestion is also given in the end.

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Experimental and Numerical Studies on Composite Tubes for the Energy Absorber of High-speed Train (복합재 튜브를 이용한 고속 열차의 에너지 흡수장치에 대한 실험 및 수치해석 연구)

  • Nguyen, Cao-Son;Jang, Hong-Kyu;Shin, Jae-Hwan;Son, Yu-Na;Kim, Chun-Gon
    • Composites Research
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    • v.24 no.1
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    • pp.1-9
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    • 2011
  • This paper presents an experimental and numerical study on composite tubes for the energy absorber of the high-speed train. The purpose of the experimental study is to find out which lay-up is the best lay-up for the energy absorber. Four lay-ups were tested using quasi static method: $[0/45/90/-45]_4$, $[0]_{16}$, $[0/90]_8$, $[0/30/-30]_5$. Two triggering methods were used to create initial damage and guarantee the progressive collapse mode: bevel edge and notch edge. As a result, $[0/45/90/-45]_4$ lay-up was find out the best lay-up among the laminates being tested. In the numerical study, a parametric analysis was done to find out the most proper way to simulate the quasi static test of a composite tube using LS-DYNA program. A single composite tube was modeled to be crashed by a moving wall. Comparison between simulation and experiment was done. Reasonable agreement between experiment and analysis was obtained. Dealing with parameter TFAIL and the mass scaling factor, this parametric study shows the ability and the limitation of LS-DYNA in modeling the quasi static test for the composite tube.

Experiment and Analysis of Mooring System for Floating Fish Cage (해상 양식시설의 계류시스템 실험 및 해석)

  • KIM Jin-Ha;KIM Hyeon-Ju;HONG Sup
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.34 no.6
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    • pp.661-665
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    • 2001
  • This paper deals with optimal mooring system to secure fish cage in a desired location, Through field investigation and paper works, we surveyed disasters by breakdown of cage frame and mooring system due to higher wave attack and selected compliant buoy mooring method for shallow water mooring system against severe coastal external forces. To analyze interaction between external forces and compliant buoy mooring system, theoretical model has developed as quasi-static nonlinear analysis. After verifying the feasibility of the numerical model compared with experiment, static analysis has tried for various mooring systems with different angle of array, number of mooring points, length of horizontal and inclined rope. Optimal mooring method using compliant buoy has selected for fish cage through numerical simulation. This results can apply for preliminary design for cage mooring system.

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A Study on the Quasi-3-Dimensional Compressible Flow Calculation by Introduction of Viscous Loss Model in Axial-Flow Compressor (점성 손실모델 도입에 의한 축류 압축기 준 3차원 압축성 유동해석)

  • 조강래;이진호;김주환
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.5
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    • pp.1044-1051
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    • 1989
  • A numerical calculation is carried out for the analysis of 3-dimensional compressible flow field in axial-flow rotating blades by using finite element method. The calculation of flow in impellers plays a dominant role in the theoretical research and design of turbomachines. Three-dimensional flow fields can be obtained by the quasi-three-dimensional iterative calculation of the flows both on blade-to-blade stream surfaces and hub-to-shroud stream surfaces with the introduction of viscous loss model in order to consider a loss due to viscosity of fluid. In devising the loss model, four primary sources of losses were identified: (1) blade profile loss (2) end wall loss (3) secondary flow loss (4) tip-leakage loss. For the consideration of an axially parabolic distribution of loss, the results of present calcullation are well agreed with the results by experiment, thus the introduction of loss model is proved to be valid.

Hybrid HMM for Transitional Gesture Classification in Thai Sign Language Translation

  • Jaruwanawat, Arunee;Chotikakamthorn, Nopporn;Werapan, Worawit
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1106-1110
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    • 2004
  • A human sign language is generally composed of both static and dynamic gestures. Each gesture is represented by a hand shape, its position, and hand movement (for a dynamic gesture). One of the problems found in automated sign language translation is on segmenting a hand movement that is part of a transitional movement from one hand gesture to another. This transitional gesture conveys no meaning, but serves as a connecting period between two consecutive gestures. Based on the observation that many dynamic gestures as appeared in Thai sign language dictionary are of quasi-periodic nature, a method was developed to differentiate between a (meaningful) dynamic gesture and a transitional movement. However, there are some meaningful dynamic gestures that are of non-periodic nature. Those gestures cannot be distinguished from a transitional movement by using the signal quasi-periodicity. This paper proposes a hybrid method using a combination of the periodicity-based gesture segmentation method with a HMM-based gesture classifier. The HMM classifier is used here to detect dynamic signs of non-periodic nature. Combined with the periodic-based gesture segmentation method, this hybrid scheme can be used to identify segments of a transitional movement. In addition, due to the use of quasi-periodic nature of many dynamic sign gestures, dimensionality of the HMM part of the proposed method is significantly reduced, resulting in computational saving as compared with a standard HMM-based method. Through experiment with real measurement, the proposed method's recognition performance is reported.

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The Effects of Information Characteristics(Direction, Consensus) on Word-of-Mouth Performance in Online Apparel Shopping (인터넷 의류쇼핑에서 온라인 구전정보특성 중 방향성과 동의성이 소비자 구매행동 변화에 미치는 영향)

  • Son, Jin-Ah;Rhee, Eun-Young
    • Journal of the Korean Society of Clothing and Textiles
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    • v.31 no.8
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    • pp.1157-1167
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    • 2007
  • Internet communications have provoked new forms of online word-of-mouth(WOM) communication and it has become more powerful. At this point, this study analyses the effects of information characteristics(direction, consensus) of online WOM. Especially, quasi-experiment can systematically manipulate the direction and the consensus of online WOM information and it perceived the difference in the effects in this study. Female consumers who have purchased clothing at online shopping mall in past 6 months participated in the experiment by completing 4 type questionnaires(N=600). Data are analyzed using Cronbach's ${\alpha}$, t-test, one way ANOVA, two-way ANOVA, Duncan's multiple range test. The Results of this study are as follows: (1) The direction of online WOM information significantly influences consumer's reliability of information, attitude, and purchase intentions. These effects are more significant when negative WOM information than positive information and two-sided information was given. (2) Though there is the difference in reliability of information, the consensus of online WOM information does not have influences on consumer's attitude and purchase intentions. (3) Consumer's clothing involvement is related to WOM information searching. The highly involved consumer is more effected by online WOM information than the lowly one.

Effects of Analytic Rubrics on Learners' Self-Directed Learning Ability in Information Technology Unit Assessment (정보기술단원 평가에서 분석적 루브릭의 적용이 학습자의 자기주도 학습력에 미치는 영향)

  • Nam, Seung-Kwon;Choi, Won-Sik
    • 대한공업교육학회지
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    • v.30 no.1
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    • pp.56-67
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    • 2005
  • The purpose of this study was to examine the effects of analytic rubrics on learners' self-directed learning ability in information technology unit assessment. The experiment and control groups were 4 classes of the 2nd grade in B middle school located in Daejeon. The pretest was performed to check the group homogeneity. For the experiment design, the nonequivalent control group design as a type of quasi-experimental design was used. The experiment was composed of 5 sessions. Statistical significance was p < .05 to verify the hypothesis, and SPSS 12.0 for Windows was used for statistical treatment. The results from this study were as follows: (1) The application of analytic rubrics in information technology unit assessment affected learners' self-directed learning ability in a positive way in 4 factor's(openness, self-concept, intrinsic motivation, self-evaluation) but does not affected in 3 factor's(autonomy, creativity, problem solving). (2) The difference in sex was not a statistically significant factor in the application of analytic rubrics in information technology unit assessment. Based on the results of the experiment, two suggestions were made to promote the application of rubrics in technology education assessment. (1) Research and development of many types of rubrics for technology education are needed. (2) Systematic training of rubrics for technology teachers is needed.

Effectiveness of the Self-care Education for the Medication and Symptoms Management on the Psychiatric Patients' Quality of life (약물 및 증상관리에 대한 자가간호교육이 정신질환자의 삶의 질에 미치는 효과)

  • Son Kyung-Hee
    • The Journal of Korean Academic Society of Nursing Education
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    • v.5 no.2
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    • pp.300-314
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    • 1999
  • This study is an attempt to evaluate the effect of the medication and symptoms self-care education on the psychiatric patients' quality of life. This exploratory study was designed to a quasi-experiment of pretest-postest with a non equivalent control group. Subjects of 40 patients who were discharged from a mental hospital in Pusan were selected to be experiment and control group, with each group consisting of 20. The research period was from March, 6 to May, 29, 1999 and the pre-post test was given before and after implementing MSSE to the both experiment and control group. The results finding were summarized as follows ; 1. subjects who attended self-care education scored significantly higher than control group in quality of life.(Z=-2.06, P=0.034) 2. Those who were in the experiment group reported more significant higher scores than control group in item of quality of life, living situation(A=-2.62 P=0.012), relations with spouse (Z=-2.31 P=0.038) and children (Z=3.37, P=0.008), fear (Z=-1 95, P=0.049) and anger(Z=-2.07 P=0.041), work functioning (Z=-2.34, P=0.021), environmental adjustment. (Z=-2.05, P=0.039)

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Evaluating the Mechanical Properties of Fiber Yarns for Developing Synthetic Fiber Chains

  • Kim, Kyeongsoo;Kim, Taewan;Kim, Namhun;Kim, Dokyoun;Kang, Yongjun;Kim, Seonjin
    • Journal of Ocean Engineering and Technology
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    • v.35 no.6
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    • pp.426-433
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    • 2021
  • In this study, three types of synthetic fiber materials were evaluated, namely, DM20, SK78, and T147, to replace steel chains in shipbuilding and offshore fields with fiber chains as there is increasing demand for chains with lighter weights and improved usabilities. The strength and quasi-static stiffness were analyzed to select suitable yarns for the fiber chains. The durability of the yarn was evaluated by performing a 3-T (time to rupture) test as a specific tension level. The results of the experiment revealed excellent dynamic stiffness in DM20 and highest values of the windward and leeward stiffness in T147. 3-T linear design characteristic curves for a specific tension level were derived for the three types of fiber materials. The findings of this study can provide insights for improving strength and durability in fiber chain design.