• Journal of Korean Elementary Science Education
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• v.42 no.1
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• pp.93-108
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• 2023

This study aims to analyze the types and roles of visualization materials presented in the third- and fourth-grade national and authorized science textbooks based on the 2015 revised curriculum. Using the type and role framework, 17 chapters were analyzed. The analysis revealed, first, that the national and authorized textbooks had different total amounts of visualization data and total amounts of simple illustrations. However, no difference in the amounts of simple illustrations and infographics used in the units was evident. The units that used the most infographics were Life, Earth and Universe, in that order, in both the national and the authorized textbooks. Second, simple illustrations were observed to have role differences according to the type of visualization data, but infographics had no such differences. Specifically, the motivational role in a simple illustration increased in all the authorized textbooks. Third, looking at the frequencies of the infographic subtypes, the Process, Structure, Comparative Analysis, and Timeline types accounted for 86% of the total, but the proportions of those subtypes varied in the national and authorized textbooks. Based on the results of this study, I suggest that to achieve differentiation in the types or roles of visualization materials, changes in the types, processes, and skills of inquiry must first occur, as must changes in the structure of chapters or lessons. Continuous research and discussion on the standards and methods for authorized textbooks are also needed.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.157-168
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• 2009

In this paper, a photovoltaic system is designed with a step up chopper and single phase PWM(Pulse Width Modulation) voltage source inverter. Where proposed Synchronous signal and control signal was processed by one-chip microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical voltage and current dropping character. The single phase PWM voltage source the inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power. from 10 to 20[%]. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In order to enhance the efficiency of photovoltaic cells, photovoltaic positioning system using sensor and microprocessor was design so that the fixed type of photovoltaic cells and photovoltaic positioning system were compared. In result, photovoltaic positioning system can improved 5% than fixed type of photovoltaic cells. In addition, I connected extra power to the system through operating the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and the phase of single-phase inverter of PWM voltage type can be synchronized. And, It controlled in order to provide stable pier to the load and the system through maintaining high lurer factor and low output power of harmonics.

• Journal of the Korean Society of Floral Art and Design
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• no.40
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• pp.3-24
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• 2019

This study aim to suggest connective potential of eco-therapy in interior therapy for integrative psychotherapy. The study method was literature review on qualitative study. The study scope was ranged as the following three steps: 1) Literature review on integrative psychological therapy; 2) Discussion on therapy and ecology in interior design; and 3) Association between three aspects of integrative psychotherapy(emotion, cognition and behavior) and psychological phases of interviewee (quasi-consideration, consideration, preparation, behavior, and maintenance). The study results are summarized below: 1) Emotional aspect of integrative psychotherapy utilizes installing and sensory aspects of space. 2) Cognitive aspect of integrative psychotherapy utilizes energetic and installing aspects of space. 3) Behavioral aspect of integrative psychotherapy utilizes structural, installing, emotional, and purposive aspects of space. This study has its significance in extending collaborative concept of plants as the decoration to broad sense of eco-therapy available as the psychological factor in organic relationship between human and environment, which will be used as the resource for design therapy training program in the future.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.351-361
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• 2023

The purpose of this paper is to help those who research and develop solar cells in university laboratories and industrial sites understand the most basic and important quantum efficiency measurement and analysis method in analyzing solar cell performance. Starting with the definition of quantum efficiency, we calculate the theoretical current density according to the band gap of the solar cell material from the solar spectrum, along with a detailed introduction to the measurement and analysis methods, and measure and analyze the theoretical current density and quantum efficiency. We discuss in depth how to analyze the performance of solar cells through Quantum efficiency measurement and analysis of solar cells is a very useful method that can give intuition to solar cell performance analysis as it can analyze solar cells according to depth (front emitter, bulk, rear surface). Students and researchers who study solar cells with a deep understanding of theoretical current density and quantum efficiency measurement analysis are expected to use it as a basis for analyzing solar cell performance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.95-109
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• 2008

We numerically analyzed the nonlinear shoaling, a plunging breaker and its accompanying energetic suspension of sediment at a bed, and a redistribution of suspended sediments by a down rush of preceding waves and the following plunger using SPH with a Gaussian kernel function, Lagrangian Dynamic Smagorinsky model (LDS), Van Rijn's pick up function. In that process, we came to the conclusion that the conventional model for the tractive force at a bottom like a quadratic law can not accurately describe the rapidly accelerating flow over a swash zone, and propose new methodology to accurately estimate the bottom tractive force. Using newly proposed wave model in this study, we can successfully duplicate severely deformed water surface profile, free falling water particles, a queuing splash after the landing of water particles on the free surface and a wave finger due to the structured vortex on a rear side of wave crest (Narayanaswamy and Dalrymple, 2002), a circulation of suspended sediments over a swash zone, net transfer of sediments clouds suspended over a swash zone toward the offshore, which so far have been regarded very difficult features to mimic in the computational fluid mechanics.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.86-90
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• 2023

The packaging of electronic devices performs a protective function to ensure that their durability and reliability are not affected by changes in the operating environment caused by external factors. Recent advances in materials have led to ongoing research into bonded packaging of heterogeneous materials such as polymers and inorganic materials in electronic devices. In this packaging process, it is important to have a binding that joins the materials and ensures the operating environment, which includes adhesion to the substrate, corrosion and oxidation resistance through moisture removal, and durability. In this study, the hygroscopicity of the coating layer by modifying the polymer surface based on PVA was evaluated by controlling and measuring the contact angle, and the adhesion was confirmed by applying water-based ink and testing according to ASTM_D3363. For the durability of the polymer surface, the IPL post-treatment process was used to improve the hardness and toughness against applied voltage, and the pencil hardness test and nanoindentation test were conducted. Through this, we analyzed and proposed solutions to ensure the reliability and durability of polymer devices in polymer microfabrication against environmental factors such as moisture, temperature fluctuations and adhesion, and surface abrasion.

• Industry Promotion Research
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• v.8 no.4
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• pp.147-162
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• 2023

This study explored the experience of social support in the education and rearing of children of immigrant women through international marriage and found its essential meaning. First of all, the husband's social support was very important, but the relationship with the husband had a different effect on childrearing and education. Parents-in-law had a positive and negative impact on child rearing and education of them due to cultural conflicts between the two countries. Their own mother was a strong support that gave them great strength just by being there, and as their children grew up, they regarded their mother as the source of bilingual education for their children. Other supporters around them were Korean friends who connected Korean society by sharing information on child care and education. Friends who spoke and communicated in their native language were emotional and psychological supporters that bonded the same experience of parenting and education for their children. In conclusion, the research participants expected a better life for themselves and their children by using a multi-layered social support system as well as a transnational family network in the process of child education and care. Accordingly, it was proposed to systematically improve the laws, systems, and policy support so that the social support system can be further strengthened at the family, community, and transnational levels for the education and care of children of immigrant women through international marriage.

• Journal of The Korean Association For Science Education
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• v.27 no.3
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• pp.212-224
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• 2007

Metabolism is one of the pivotal biology concepts, but many students have difficulty understanding it. The purposes of this study were (1) to explore 8th graders' conceptual change of an enzyme after classes of experimenting enzyme reaction and interpreting data using systematic analogies, (2) to discover the role of systematic analogies to enhance students' understanding, and (3) to explain students' difficulty understanding concepts as the ontological features. Systematic analogies were designed to encourage students to interpret their lab activities on enzyme reaction rates. Data were collected by using the pre-test and the post-test of open-ended form, students' worksheets, and interviews with students. After classes, the number of students to engender scientific conceptions about the function of enzyme, its structure, and its mechanism has increased. But more students failed to understand the reaction mechanisms having ontological features of equilibration processes than to understand the function of enzyme having ontological features of event-like processes. Even though the concepts of enzymes are hard to grasp owing to their ontological attributes of equilibration processes, a part of students' conceptions successfully progressed from the idea belonging to event-like processes to one belonging to equilibration processes. And systematic analogies were found to contribute in enhancing students' conceptual change of the enzyme reaction.

• The Journal of the Acoustical Society of Korea
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• v.29 no.3
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• pp.191-199
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• 2010

Physical modeling is a synthesis method of high quality sound which is similar to real sound for musical instruments. However, since physical modeling requires a lot of parameters to synthesize sound of a musical instrument, it prevents real-time processing for the musical instrument which supports a large number of sounds simultaneously. To solve this problem, this paper proposes a single instruction multiple data (SIMD) parallel processor that supports real-time processing of sound synthesis of guitar, a representative plucked string musical instrument. To control six strings of guitar, we used a SIMD parallel processor which consists of six processing elements (PEs). Each PE supports modeling of the corresponding string. The proposed SIMD processor can generate synthesized sounds of six strings simultaneously when a parallel synthesis algorithm receives excitation signals and parameters of each string as an input. Experimental results using a sampling rate 44.1 kHz and 16 bits quantization indicate that synthesis sounds using the proposed parallel processor were very similar to original sound. In addition, the proposed parallel processor outperforms commercial TI's TMS320C6416 in terms of execution time (8.9x better) and energy efficiency (39.8x better).

• Journal of Sensor Science and Technology
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• v.33 no.1
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• pp.34-39
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• 2024

Energy harvesting technology that converts the wasted energy resources into electrical energy is emerging as a semipermanent power source for self-powered electronics and wireless low-power sensor systems. Among the various energy conversion techniques, flexible piezoelectric energy harvesters (f-PEHs), using materials with piezoelectric effects, have attracted significant interest because they can harvest a small mechanical energy into electrical signals without constraints of time and space in various environments. In this study, we used a flexible piezoelectric composite film fabricated by dispersing BaHf_xTi_(1-x)O₃ (x = 0, 0.01, 0.05, 0.1) piezoelectric powders inside a polymeric matrix to facilitate f-PEHs. The fabricated f-PEH with optimal Hf contents (x = 0.05) generated a maximum output voltage of 0.95 V and current signal of 130 nA with stable electrical/mechanical disabilities under periodically bending deformations. In addition, we demonstrated a cantilever-type f-PEH and investigated its potential as a sensor by characterizing the output performance under mechanical vibrations at various frequencies. This study provides the breakthrough for realizing self-powered energy harvesting and sensing systems by adopting the lead-free piezoelectric composites under vibrational environments.