• Title/Summary/Keyword: Experimental designs

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Numerical Analysis of Welding Residual Stress Using Heat Source Models for the Multi-Pass Weldment

  • Bae, Dong-Ho;Kim, Chul-Han;Cho, Seon-Young;Hong, Jung-Kyun;Tsai, Chon-Liang
    • Journal of Mechanical Science and Technology
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    • v.16 no.9
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    • pp.1054-1064
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    • 2002
  • Numerical prediction of welding-induced residual stresses using the finite element method has been a common practice in the development or refinement of welded product designs. Various researchers have studied several thermal models associated with the welding process. Among these thermal models, ramp heat input and double-ellipsoid moving source have been investigated. These heat-source models predict the temperature fields and history with or without accuracy. However, these models can predict the thermal characteristics of the welding process that influence the formation of the inherent plastic strains, which ultimately determines the final state of residual stresses in the weldment. The magnitude and distribution of residual stresses are compared. Although the two models predict similar magnitude of the longitudinal stress, the double-ellipsoid moving source model predicts wider tensile stress zones than the other one. And, both the ramp heating and moving source models predict the stress results in reasonable agreement with the experimental data.

Three-Dimensional Analysis of the Shapes of Gathered Skirts (개더스커트 형상프로포션의 3차원적 해석)

  • Lee, Myung-Hee;Jung, Hee-Kyeong
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.11 s.158
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    • pp.1598-1607
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    • 2006
  • The purpose of this study was to analyze the proportion of gathered skirts using a three-dimensional measurement system. And in this experiment, we have attempted to accumulate three-dimensional data of wearing model and find out adequate methods for analyzing shape of clothes. The experimental design consists of two factorial designs. We established three different kinds of fabrics, ratio of gathers. The measurement tool for three-dimensional model was whole body 3D scanner(Exima-WBS2H). Analysis program used in experiment is RapidForm 2004 PP1 and Pattern Design 2000. Data analysis utilizes SPSS WIN 10.0 Package. As the results show, there were different effect of gather and proportion of shapes among the measurements of width, thickness and areas made by different lines of vision in cross-sectional silhouette. And there were difference shapes of section area at each part of gathered skirts between vertical-outline silhouette and vortical-plane silhouette made by gathering conditions. And also the cross-sectional silhouettes and vertical silhouettes were related to shape of clothes.

An Experimental Examination of Customer Preferences on Mobile Interfaces (모바일 서비스 고객선호도에 관한 실증연구)

  • Baek, Seung-Ik;Cho, Min;Kim, Bong-Jun
    • Korean Management Science Review
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    • v.23 no.3
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    • pp.27-39
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    • 2006
  • Designing mobile Interfaces is fundamentally different from designing online interfaces. Not only are there differences in underlying technologies, but also in the way people use mobile Interfaces. If these differences are not taken into account in designing mobile interfaces, mobile services are likely to fail. If mobile services do not deliver what people want, these services will fail no matter how excellent the underlying technology is. The user interface design commonly used in mobile services is based on multi-layered approach, which is not very user-friendly. A well designed single layered user Interface will be more user friendly than the conventional one and it will be having edge over others. However, it is quite difficult to Provide a single layered user Interface in a small screen. This study aims at examining how design attributes of mobile interfaces affect customer preferences. In order to explore customer preferences to each design attribute of mobile interfaces, we measure and analyze customer's WTP (Willingness To Pay) toward their different interface designs. Ultimately, throughout the study, we try to answer how to design mobile interfaces in small screen of mobile devices. In addition, we propose an optimal design solution that customers likely prefer.

A Study on the Comparison of Design Concepts in Libeskind's Jewish Museums (리베스킨트의 유태인 박물관에 나타난 건축 개념 비교에 관한 연구)

  • Chung, Tae-Yong
    • Korean Institute of Interior Design Journal
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    • v.21 no.2
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    • pp.46-55
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    • 2012
  • This study aims to analyze the design concepts of Libeskind's Jewish museums through their comparisons for figuring out his design intentions and characteristics in the realization process. Libeskind's realized four Jewish museums are chosen for this study. For more concrete study, their extracting and application process are also reviewed. The comparison of his museum designs can be good examples in that they show different design approaches on the same architectural type, Jewish museum, to tell their something in common from differences. He could realize his architectural thoughts and configuration methods made by experimental drawings for the first time as real buildings through a series of Jewish museum projects. The commonness of Libeskind's Jewish museums lie on their sharing design concept of Jewish 'history and memory', especially Holocaust, and realized as in contrast to surroundings and 'labyrinth' of spatial configuration to maximize spectator's experiences. As Libeskind regards museum architecture as a carrier of 'time and place', he tried to reflect surrounding context including places, cities, persons and events about museum programs. As a result, unprecedented museums which are not related to traditional museum systems about circulation and spatial configuration are suggested for users to experience Jewish life and history through architecture.

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The analysis of Trends and Contents of Nursing Intervention Research for Cancer Patients in Korea (국내 암환자를 대상으로 한 간호중재 연구현황 및 분석)

  • Hong, Myung Sun;Yom, Young Hee;Kim, Geun Myun
    • Asian Oncology Nursing
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    • v.12 no.4
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    • pp.247-256
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    • 2012
  • Purpose: In this study, the articles which developed and applied nursing interventions for patients with cancer were reviewed and analyzed. Methods: The analysis was performed in light of 171 pieces of literature on nursing interventions for patients with cancer published between 1991 and 2010. Results: Approximately half of the studies have been published between 2006 and 2010. The quasi-experimental designs using nonequivalent control group and no-synchronized design were the most common form of research design among the 71 papers constituting 41.52% of the total. The most commonly used nursing intervention was education (25.2%), followed by massage (20.4%) and exercise (11.5%). The most common outcome variable was anxiety (11.8%), followed by pain (8.0%) and nausea and vomiting (7.3%). Conclusion: The results of this study can provide useful information for the development of nursing interventions in specialized areas. Systematic literature review or meta-analysis is needed in this area.

Hypercalciuria and febrile convulsion in children under 5 years old

  • Gorabi, Vahid Seddighi;Nikkhoo, Bahram;Faraji, Obeidollah;Mohammadkhani, Mona;Mirzaee, Sattar;Rasouli, Mohammad Aziz;Afkhamzadeh, Abdorrahim
    • Clinical and Experimental Pediatrics
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    • v.61 no.4
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    • pp.129-131
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    • 2018
  • Purpose: The association between hypercalciuria and febrile convulsion is controversial. The present study aimed to investigate the statistical association between hypercalciuria and childhood febrile convulsions. Methods: Overall, 160 children aged 6 months to 5 years, including 80 children with febrile convulsion and 80 febrile children without convulsion (comparison group), were recruited. All laboratory tests, including 24-hour urine calcium, were undertaken in an academic clinical laboratory. Results: Forty-five children of the febrile convulsion group (60%) and 30 of the comparison group (40%) had hypercalciuria. There was a significant difference between the 2 groups (P=0.02). Conclusion: Our results indicated that there is a statistical association between convulsion and hypercalciuria in children. Since we found this association with a cross-sectional assessment, further studies, especially prospective and controlled designs, are needed.

The utilities of U-shape EM sensor in stress monitoring

  • Wang, Guodun;Wang, Ming L.
    • Structural Engineering and Mechanics
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    • v.17 no.3_4
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    • pp.291-302
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    • 2004
  • In this paper, load monitoring technologies using U-shape Magnetoelastic (EM or ME) sensors have been exploited systemically for the first time. The steel rod to be tested is the Japan 7 mm piano steel rod. The load dependence of the magnetic properties of the piano steel rod was manifested. Two experimental designs of U-shape magnetoelastic sensors were introduced, one with double pick-up concentric coils wound on the rod to be tested, the other with pick-up coil on one yoke foot. The former design is used to derive the correlation of the relative permeability with elastic tension, while the latter is aimed to reflect the stress induced magnetic flux variation along the magnetic circuit. Magnetostatic simulations provide interpretations for the yoke foot sensing technology. Tests with double pick-up coils indicate that under proper working points (primary voltages), the relative permeability varies linearly with the axial load for the Japan 7 mm piano steel rod. Tests with pick-up coil on the yoke foot show that the integrated sensing voltage changes quadratically with the load, and error is more acceptable when the working point is high enough.

Neuro-fuzzy based prediction of the durability of self-consolidating concrete to various sodium sulfate exposure regimes

  • Bassuoni, M.T.;Nehdi, M.L.
    • Computers and Concrete
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    • v.5 no.6
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    • pp.573-597
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    • 2008
  • Among artificial intelligence-based computational techniques, adaptive neuro-fuzzy inference systems (ANFIS) are particularly suitable for modelling complex systems with known input-output data sets. Such systems can be efficient in modelling non-linear, complex and ambiguous behaviour of cement-based materials undergoing single, dual or multiple damage factors of different forms (chemical, physical and structural). Due to the well-known complexity of sulfate attack on cement-based materials, the current work investigates the use of ANFIS to model the behaviour of a wide range of self-consolidating concrete (SCC) mixture designs under various high-concentration sodium sulfate exposure regimes including full immersion, wetting-drying, partial immersion, freezing-thawing, and cyclic cold-hot conditions with or without sustained flexural loading. Three ANFIS models have been developed to predict the expansion, reduction in elastic dynamic modulus, and starting time of failure of the tested SCC specimens under the various high-concentration sodium sulfate exposure regimes. A fuzzy inference system was also developed to predict the level of aggression of environmental conditions associated with very severe sodium sulfate attack based on temperature, relative humidity and degree of wetting-drying. The results show that predictions of the ANFIS and fuzzy inference systems were rational and accurate, with errors not exceeding 5%. Sensitivity analyses showed that the trends of results given by the models had good agreement with actual experimental results and with thermal, mineralogical and micro-analytical studies.

Cantilever beam vibration sensor based on the axial property of fiber Bragg grating

  • Casas-Ramos, Miguel A.;Sandoval-Romero, G.E.
    • Smart Structures and Systems
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    • v.19 no.6
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    • pp.625-631
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    • 2017
  • In the fields of civil engineering and seismology, it is essential to detect and tracking the vibrations, and the fiber Bragg gratings (FBGs) are typically used as sensors to measure vibrations. Where, one of the most popular and detailed approaches to use FBGs as vibration sensors involves the use of cantilever beam designs, which adds a mass to measure low and moderate frequencies (from 20 Hz up to 1 kHz) with high sensitivities (greater than 10 pm/g). The design consists of a bending strain in the cantilever that is simultaneously transferred to the FBG, resulting in a shift in the wavelength that is proportional to the strain experienced by the cantilever. In this work, we present the experimental results of a vibration sensor design using a cantilever beam to generate an axial uniform strain in the FBG in-line with the vertical axis, which modifies the cantilever's natural frequency that allows the sensor to have a wide frequency broadband without losing sensitivity. This sensor achieved a sensitivity of about 339 pm/g and a natural frequency of 227.3 Hz. The presented design compared with the traditional cantilever beam-based FBG vibration sensors, has the advantages of a simple design for detection on vibration-sensitive structures and its physical parameters can be easily modified in order to satisfy the requirements of the desired vibration measurements.

Design and Analysis of Experimental Anechoic Chamber for Localization

  • Kim, Keon-Wook
    • The Journal of the Acoustical Society of Korea
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    • v.31 no.4
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    • pp.225-234
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    • 2012
  • The anechoic chamber is essential tool to measure the various acoustic parameters with high precision. The chamber provides the climate controlled indoor environments but requires the dedicated room at a great cost in order to isolate and absorb sound field. Provided the purpose of the chamber is specific to the experiments of sound localization, the performance requirements excluding free field can be alleviated for cost effective solution. This paper designs low cost and profile anechoic chamber based on acoustic pyramids and evaluates the performance specified by the Annex of ISO 3745. Data analysis is employed to measure the free and hemi-free field performance over five straight paths for working areas and four paths for non-working areas. The identical two measurement campaigns were conducted for free and hemi-free field chamber which is easily interchangeable by simple labor in this chamber design. In the working area with conventional speaker, the results of these analyses demonstrate that lab-designed anechoic chamber is in conformance with ISO 3745 for 250 Hz - 16 kHz one-third octave band at free field chamber and for 1 kHz - 16 kHz one-third octave band at hemi-free field chamber.