• Title/Summary/Keyword: Couple analysis

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Synthesis of CoSe2/RGO Composites and Its Application as a Counter Electrode for Dye-Sensitized Solar Cells

  • Ko, Yohan;Choi, Wooyeol;Kim, Youbin;Lee, Chanyong;Jun, Yongseok;Kim, Junhee
    • Journal of Electrochemical Science and Technology
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    • v.10 no.3
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    • pp.313-320
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    • 2019
  • In this study, cobalt diselenide ($CoSe_2$) and the composites ($CoSe_2@RGO$) of $CoSe_2$ and reduced graphene oxide (RGO) were synthesized by a facile hydrothermal reaction using cobalt ions and selenide source with or without graphene oxide (GO). The formation of $CoSe_2@RGO$ composites was identified by analysis with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and scanning electron microscopy (SEM). Electrochemical analyses demonstrated that the $CoSe_2@RGO$ composites have excellent catalytic activity for the reduction of $I_3{^-}$, possibly indicating a synergetic effect of $CoSe_2$ and RGO. As a consequence, the $CoSe_2@RGO$ composites were applied as a counter electrode in DSSC for the reduction of redox couple electrolyte, and exhibiting the comparable power conversion efficiency (7.01%) to the rare metal platinum (Pt) based photovoltaic device (6.77%).

Tensile and fracture characterization using a simplified digital image correlation test set-up

  • Kumar, Abhishek;Vishnuvardhan, S.;Murthy, A. Ramachandra;Raghava, G.
    • Structural Engineering and Mechanics
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    • v.69 no.4
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    • pp.467-477
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    • 2019
  • Digital image correlation (DIC) is now a popular and extensively used full-field metrology technique. In general, DIC is performed by using a turnkey solution offered by various manufacturers of DIC. In this paper, a simple and economical set-up for DIC is proposed which uses easily accessible digital single-lens reflex (DSLR) camera rather than industrial couple-charged device (CCD) cameras. The paper gives a description of aspects of carrying a DIC experiment which includes experimental set-up, specimen preparation, image acquisition and analysis. The details provided here will be helpful to carry DIC experiments without specialized DIC testing rig. To validate the responses obtained from proposed DIC set-up, tension and fatigue tests on specimens made of IS 2062 Gr. E300 steel are determined. Tensile parameters for a flat specimen and stress intensity factor for an eccentrically-loaded single edge notch tension specimen are evaluated from results of DIC experiment. Results obtained from proposed DIC experiments are compared with those obtained from conventional methods and are found to be in close agreement. It is also noted that the high resolution of DSLR allows the use of proposed approach for fracture characterization which could not be carried out with a typical turnkey DIC solution employing a camera of 2MP resolution.

Effectiveness of Repeated Marriage Checkups in a Family Center (정례적 결혼검진의 가족센터 적용에 관한 효과성 연구)

  • Park, Woochul
    • Human Ecology Research
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    • v.60 no.1
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    • pp.69-86
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    • 2022
  • The present study examined the effectiveness of repeated marriage checkups at intervals of six months in a Family Center in Seoul. To achieve this, the pilot study protocol (Park, 2019) was adapted, emphasizing strength-based, counseling-oriented approaches. Two couples and family therapists with master's degrees were trained and their practice was monitored to ensure program fidelity. The methods employed for the assessment of marriage checkup were an online survey, a video recording of couple problem-solving, and a clinical interview. A total of 14 couples participated in the 1st checkup, 10 of whom also completed the 2nd checkup. Couples with varying levels of marital satisfaction participated in the program. Descriptive statistics indicated gradual increases over 8-9 months in diverse indices such as marital satisfaction and relationship strength, while other indices fluctuated slightly but converged to higher levels over time. A non-parametric analysis appropriate for small samples demonstrated statistically significant increases over the 8-9 months in marital satisfaction among couples. The current study evidenced the effectiveness of repeated marriage checkups in the Family Center, which is the primary public institution for family policy and services in Korea. Repeated marriage checkups are therefore a promising way to enhance couples' relationship health and improve the family management system of the Family Center.

Comparative Analysis of IoT Enabled Multi Scanning Parking Model for Prediction of Available Parking Space with Existing Models

  • Anchal, Anchal;Mittal, Pooja
    • International Journal of Computer Science & Network Security
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    • v.22 no.8
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    • pp.404-412
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    • 2022
  • The development in the field of the internet of things (IoT) have improved the quality of the life and also strengthened different areas in the society. All cities across the world are seeking to become smarter. The creation of a smart parking system is the essential use case in smart cities. In recent couple of years, the number of vehicles has increased significantly. As a result, it is critical to make the use of technology that enables hassle-free parking in both public and private spaces. In conventional parking systems, drivers are not able to find free parking space. Conventional systems requires more human interference in a parking lots. To manage these circumstances there is an intense need of IoT enabled parking solution that includes the well defined architecture that will contain the following components such as smart sensors, communication agreement and software solution. For implementing such a smart parking system in this paper we proposed a design of smart parking system and also compare it with convetional system. The proposed design utilizes sensors based on IoT and Data Mining techniques to handle real time management of the parking system. IoT enabled smart parking solution minimizes the human interference and also saves energy, money and time.

QUANTUM CONTROL OF PARTICLES AT MATTER SURFACE OUTSIDE THE DOMAIN

  • Quan-Fang Wang
    • Nonlinear Functional Analysis and Applications
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    • v.28 no.1
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    • pp.11-36
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    • 2023
  • In this presentation, the particles at the matter surface (metal, crystal, nano) will be considered as the control target outside the physical domain. As is well known that control problems of quantum particles at surface had been investigated in various aspects in last couple of years, but the realization of control would become rather difficult than theoretical results. Especially, whether surface control would be valid? what kind of particles at what kind of matter surfaces can be controlled? so many questions still left as the mystery in the current research literature and papers. It means that the direct control sometime does not easy. On the other hands, control outside the physical domain is quite a interest consideration in mathematics, physics and chemistry. The main plan is to take the quantum systems operator (such as Laplacian ∆) in the form of fractional operator (∆s , 0 < s < 1), then to consider the control outside of physical domain. Fortunately, there are many published articles in the field of applied mathematics can be referred for the achievement of control outside of domain. The external quantum control would be a fresh concept to do the physical control, first in the theoretic, second in the computational, final in the experimental issues.

Numerical Analysis on the Flow Distribution in Ondol Flue Channel (산고래 온돌연도내의 유동분포에 관한 수치해석)

  • Man Man-Ki;Lee Seung Woo
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.12 no.4
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    • pp.264-274
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    • 1983
  • Two-dimensional jet flows into a couple of confined rectangular enclosures such as an Ondol flue channel and their flow distributions were analyzed by numerical graphics : rectangular space in one enclosure is vacated and the other has 8 rectangular small posts. Both enclosures have a protruded inlet nozzle and on outlet on its center line. Steady state incompressible laminar viscous flow was assumed. The primitive forms of Navier-Stokes equations and continuity equation in a cartesian coordinate system were solved numerically by the Marker and Cell method for Reynolds numbers of 5, 10, 20, 30 and 40. From the numerical graphics it was found that the flow regions in both enclosures were devided into tow parts ; one part was the jet flow localized in a narrow center region of the enclosure and the other part was the very slow recirculating flow occupying the rest of the flow region in the enclosures. However there were a little differences in the shapes of jet flow in both enclosures for Reynolds numbers of 5 and 10 and also in the shapes of recirculating flows in both enclosures for all Reynolds number. Also it was found that waving flow appeared right before the outlet at Reynolds number of 20 and more.

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A Case Study on the Pre-service Math Teacher's Development of AI Literacy and SW Competency (예비수학교사의 AI 소양과 SW 역량 계발에 관한 사례 연구)

  • Kim, Dong Hwa;Kim, Seung Ho
    • East Asian mathematical journal
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    • v.39 no.2
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    • pp.93-117
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    • 2023
  • The aim of this study is to explore the pre-service math teachers' characteristics of education to develop their AI literacy and SW competency, and to derive some implications. We conducted a 14-hours AI and SW education program for pre-service teachers with theory and practice, and an analysis on class observation data, video frames of classes and interview, Python programming assignments and papers. The results of this case study for 3 pre-service teachers are as follows. First, two students understood artificial neural network and deep learning system accurately, furthermore, all students conducted a couple of explorations related with performance improvement of deep learning system with interest. Second, coding and exploration activities using Python improved students' computational thinking as well as SW competency, which help them give convergence education in the future. Third, they responded positively to the necessity of AI literacy and SW competency development, and to applying coding to math class. Lastly, it's necessary to endeavor to give a coding education to the student's eye level according to his or her prerequisite and to ease the burden of student's studying AI technology.

Testing Differences of Leisure Satisfaction by Demogrpahic Characteristics of MTB participants

  • MOON, Bo Ra;LEE, Hwan Yeol;SEO, Won Jae
    • Journal of Sport and Applied Science
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    • v.3 no.1
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    • pp.27-34
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    • 2019
  • Purpose: Mountain biking as a sport and recreational activity has grown rapidly over the previous two decades. The purpose of this study is to analyze differences of leisure satisfaction by demographic characteristics of mountain bike participants. Research design, data, and methodology: To accomplish the purpose, the study employed purposive sample method among nonprobability sampling and collected data from 300 participants. Of collected data, 288 responses were analyzed excepted for uncompleted responses. To analyze data, study utilized statistical techniques including descriptive statistics, reliability analysis, independent-sample t-test, and one-way ANOVA, and to verify difference between individual groups in relation to significant results, Duncan's multiple range was conducted. Results: Findings indicated no differences of leisure satisfaction by gender. Similarly, education level and occupations have not influence leisure satisfaction. Yet, differences of leisure satisfaction by participation frequencies were observed. Of participation frequencies, participants riding 5 times a week were more satisfied with MTB participation than the other groups participating less 3 times a week. Conclusions: The findings provide a couple of insights in terms of promoting MTB participation. In specific, results indicated that MTB would be attractive sports that is able to appeal huge populations regardless of their education and occupation. Furthermore, consistent participation is judged an effective way to increase psychological, educational, and social satisfaction. In this sense, regional MTB clubs could play a salient role in motivating riders to more participate in MTB. Hence, establishing strategies for encouraging club activities are needed.

Market Expansion Strategies for Small or Medium-sized Construction Companies by Developing Quantitative Risk Assessment Model

  • Yoo, Jinhyuk;Koh, Seungyoon;Seo, Induck;Cha, Heesung
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.742-743
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    • 2015
  • Korean construction industry has developed with national economy growth for a couple of decades. However, because of slump of real estate, the domestic construction industry was intimidated. In this situation, many construction company has no choice but to go abroad to find construction projects. However, almost small or medium-sized construction companies are very hard to operate their business because they have small funding ability and weak labor power. Therefore, this study aims to propose an assessment tool through analyzing risk factors of overseas construction projects for small or medium-sized companies by examining preceding research and interviewing industry experts. Weights of the risk factors are determined through the surveys of the industry practitioners. All of the data is configured into the assessment tool and this converts the quantitative information which leads to the optimal of strategies choice. This paper provides a quantitative measurement of possible performance and detailed assessment of each itemized risk factors. This assessment tool is qualified for industry experts so that it can safely be applied to the future projects. Ultimately, many small or medium sized construction companies will benefit from the tool proposed in this study to examine the potential of the overseas market expansion.

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Free vibration analysis of sandwich cylindrical panel composed of graphene nanoplatelets reinforcement core integrated with Piezoelectric Face-sheets

  • Khashayar Arshadi;Mohammad Arefi
    • Steel and Composite Structures
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    • v.50 no.1
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    • pp.63-75
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    • 2024
  • In this paper, the modified couple stress theory (MCST) and first order shear deformation theory (FSDT) are employed to investigate the free vibration and bending analyses of a three-layered micro-shell sandwiched by piezoelectric layers subjected to an applied voltage and reinforced graphene nanoplatelets (GPLs) under external and internal pressure. The micro-shell is resting on an elastic foundation modeled as Pasternak model. The mixture's rule and Halpin-Tsai model are utilized to compute the effective mechanical properties. By applying Hamilton's principle, the motion equations and associated boundary conditions are derived. Static/ dynamic results are obtained using Navier's method. The results are validated with the previously published works. The numerical results are presented to study and discuss the influences of various parameters on the natural frequencies and deflection of the micro-shell, such as applied voltage, thickness of the piezoelectric layer to radius, length to radius ratio, volume fraction and various distribution pattern of the GPLs, thickness-to-length scale parameter, and foundation coefficients for the both external and internal pressure. The main novelty of this work is simultaneous effect of graphene nanoplatelets as reinforcement and piezoelectric layers on the bending and vibration characteristics of the sandwich micro shell.