• Journal of the Korea Institute of Building Construction
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• v.22 no.6
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• pp.689-700
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• 2022

Layout work for building structures requires high precision to construct structural elements in the correct location. However, the accuracy and precision of the layout position are affected by the worker's skill, and productivity can be reduced when there is information loss and error. To solve this problem, it is necessary to automate the overall layout operation and introduce information technology, and layout process automation using construction robots can be an effective means of doing this. This study develops a prototype of an automated layout robot for building structures and evaluates its basic performance. The developed robot is largely composed of driving, marking, sensing, and control units, and is designed to enable various driving methods, and movement and rotation of the marking unit in consideration of the environment on structural work. The driving and marking performance experiments showed satisfactory performance in terms of driving distance error and marking quality, while the need for improvement in terms of some driving methods and marking precision was confirmed. Based on the results of this study, we intend to continuously improve the robot's performance and establish an automation system for overall layout work process.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.4
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• pp.153-157
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• 2023

In order to manufacture a semiconductor circuit, etching, cleaning, and deposition processes are repeated. During these processes, the inside of the processing chamber is exposed to corrosive plasma. Therefore, the coating of the inner wall of the semiconductor equipment with a plasma-resistant material has been attempted to minimize the etching of the coating and particle contaminant generation. In this study, we mixed AlF₃ powder with the solid-state reacted yttrium oxyfluoride (YOF) in order to increase plasma-etching resistance of the plasma spray coated YOF layer. Effects of the mixing ratio of AlF₃ with YOF powder on crystal structure, microstructure and chemical composition were investigated using XRD and FE-SEM. The plasma-etching ratios of the plasma-spray coated layers were calculated and correlation with AlF₃ mixing ratio was analyzed.

• Journal of Practical Agriculture & Fisheries Research
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• v.8 no.1
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• pp.30-42
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• 2006

This experiment was conducted to investigate current situation and plant grouping by light and watering of mingled several cacti and succulents in a pot. The main 11 cacti are consist of Myrtillocactus geometrizans (Mart.) Cons., Gymnocalycium mihanovichii var. friedrichii Werd., Marginatocereus marginatus(DC.) Backbg., Eriocactus leninghausii (Hge. Jr.) Backbg, Notocactus scopa (Spreng.) Berg., Lobivia nealeana Backbg., Mammillaria elongata var. intertexta (DC.) SD., Pseudoespostoa (Vp1.) Backbg., Mammillaria albilanata Backbg., Mammillaria klissingiana Bod. and Espostoa lanata (HBK.) Br. & R. The main 10 succulents are Kalanchoe thyrsifolia Harv., Portulacaria afra var. foliis-variegatis Jacobs., Crassula perforata Thunbg., Echeveria pulvinata Rose, Aeonium arboreum cv. atropurpureum., Echeveria lauii Moran & J. Meyran, Pachypodium lamerei Drake, Sedum rubrotinctum cv. Aurora Boom., Aloe mitriformis Mill., and Euphorbia coerulescens Haw. The cacti were native to Mexico, Brazil, Peru, Paraguay, Ecuador, etc. The sucullents were native to Mexico, Africa, Gran Canaria, Madagascar, etc. Most of all the cacti and sucullents in the experiment are growing well under full sun or light shade, however Portulacaria afra var. foliis-variegatis Jacobs, and Sedum rubrotinctum cv. Aurora Boom. did not influenced by light. And all the plants require a little or moderate watering. Thus, planting by similar required water and light, when growing in a pot of several cacti and succulents, might be decreased the rate of death causing by their different plant physiology.

• Journal of the Korean Geotechnical Society
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• v.22 no.1
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• pp.35-44
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• 2006

In general typically granular soils contain a certain amount of fines. It is also widely recognized that foundation soils under working loads show highly non-linear behavior from very early stages of loading. In the present study, a series of laboratory tests with sands of different silt contents are conducted and methods to assess strength and stiffiness characteristics are proposed. Modified hyperbolic stress-strain model is used to analyze non-linearity of silty sands in terms of non-linear Degradation parameters f and g as a function of silt contents and Relative density Dr. Stress-strain curves were obtained from a series of triaxial tests on sands containing different amounts of silt. Initial shear modulus, which is used to normalize Degradation modulus of silty sands, was determined from resonant column test results. From the laboratory test results, it was observed that, as the Relative density increases, values of f decrease and those of g increase. In addition, it was found that values of f and g increase and decrease respectively as a Skeleton void ratio $(e_{sk})$ increases.

• Korea Trade Review
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• v.42 no.4
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• pp.69-91
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• 2017

Since the global financial crisis, major countries have been executing policies related to two top-priority goals to create more jobs: revitalization of entrepreneur activity and the cultivation of small and medium-sized companies. In South Korea, the interest of policy makers is increasingly focusing on the role of SMEs that have a technological competitive edge in the realization of a "job-centered creative economy." Due to the nature of the field, the health and medical industry requires a particularly long time until the achievement of industrialization, Also, because of the complex distribution structure, it is essential for related government ministries and institutions to jointly devise strategies. A lack of policy supports for the industry has thus far resulted in its development being relegated for the most part of small and medium-sized companies, which consequently means low global competitiveness. Now is the time for the South Korean government to provide the revolutionary supported options and strategies. This study aims to propose a general policy direction and policy areas for the cultivation of Korea's small and medium-sized companies in the healthcare industry into global small giant companies through an exploration of the German case. It is crucial to first cultivate the international competitiveness of Korean small and medium-sized companies (as in the case of Germany) so that they can grow into global small giant companies. Another important task is the creation of an environment that expedites the qualitative growth of promising SMEs as well as technological development. After securing competitiveness in terms of both product quality and technology in the global health market, substantive policy supports will be necessary to cultivate global small giant companies that are export-based (e.g. job creation effect, sales value added).

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.291-296
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• 2022

This study was conducted on curcumin which had increased bioavailability as a potential AChE inhibitor for the treatment of neurodegenerative diseases. The purpose of this study is to confirm the in vitro neuroprotective effect on Aricumin (turmeric extract). To confirm the neuroprotective effect, AChE inhibition for Aricumin was evaluated, and cell viability was analyzed for HT-22cell, and oxidative stress (glutamate, H₂O₂)-induced HT-22 cytotoxicity was evaluated. As a result of the change in the AChE inhibition rate of Aricumin (Turmeric extract), it was confirmed that Aricumin at a concentration of 39.06㎍/ml or higher inhibited AChE activity by about 20% and more. And it was confirmed that the cytotoxicity of HT-22 cells induced by oxidative stress (Gluamate 5 mM and H₂O₂ 500 µM) was significantly inhibited from 0.01 to 0.1 mg/ml concentration (p<005). These results suggest that Aricumin (turmeric extract) have potential neuroprotective effects.

• Smart Media Journal
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• v.12 no.10
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• pp.63-70
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• 2023

Recently, energy consumption for heating costs, which is 35% of smart farm energy costs, has increased, requiring energy consumption efficiency, and the importance of new and renewable energy is increasing due to concerns about the realization of electricity bills. Renewable energy belongs to hydropower, wind, and solar power, of which solar energy is a power generation technology that converts it into electrical energy, and this technology has less impact on the environment and is simple to maintain. In this study, based on the greenhouse heat storage tank and heat pump data, the factors that affect the heat storage tank are selected and a heat storage tank supply temperature prediction model is developed. It is predicted using Long Short-Term Memory (LSTM), which is effective for time series data analysis and prediction, and XGBoost model, which is superior to other ensemble learning techniques. By predicting the temperature of the heat pump heat storage tank, energy consumption may be optimized and system operation may be optimized. In addition, we intend to link it to the smart farm energy integrated operation system, such as reducing heating and cooling costs and improving the energy independence of farmers due to the use of solar power. By managing the supply of waste heat energy through the platform and deriving the maximum heating load and energy values required for crop growth by season and time, an optimal energy management plan is derived based on this.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.5
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• pp.375-387
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• 2023

The subsea power cables are increasingly important for harvesting renewable energies as we develop offshore wind farms located at a long distance from shore. Particularly, the continuous flexural motion of inter-array dynamic power cable of floating offshore wind turbine causes tremendous fatigue damages on the cable. As the subsea power cable consists of the helical structures with various components unlike a mooring line and a steel pipe riser, the fatigue analysis of the cables should be performed using special procedures that consider stick/slip phenomenon. This phenomenon occurs between inner helically wound components when they are tensioned or compressed by environmental loads and the floater motions. In particular, Vortex-induced vibration (VIV) can be generated by currents and have significant impacts on the fatigue life of the cable. In this study, the procedure for VIV fatigue analysis of the dynamic power cable has been established. Additionally, the respective roles of programs employed and required inputs and outputs are explained in detail. Demonstrations of case studies are provided under severely sheared currents to investigate the influences on amplitude variations of dynamic power cables caused by the excitation of high mode numbers. Finally, sensitivity studies have been performed to compare dynamic cable design parameters, specifically, structural damping ratio, higher order harmonics, and lift coefficients tables. In the future, one of the fundamental assumptions to assess the VIV response will be examined in detail, namely a narrow-banded Gaussian process derived from the VIV amplitudes. Although this approach is consistent with current industry standards, the level of consistency and the potential errors between the Gaussian process and the fatigue damage generated from deterministic time-domain results are to be confirmed to verify VIV fatigue analysis procedure for slender marine structures.

• 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.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.1
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• pp.22-29
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• 2024

In this study, we summarized the definition of smart vegetable seedling production technology, analysis of smart seedling production system, a hardware and software configuration model for smart seedling production system, research and development trends in smart seedling production system, and proposed future research and development plans for smart seedling production technology. Smart vegetable seedling production is a data-based seedling production, management, and distribution system that utilizes 4th Industrial Revolution technology to improve seedling productivity and quality. The production of vegetable seedlings using smart seedling production technology can be efficiently managed by collecting, analyzing, and managing information on seedlings, environment, and tasks at each stage of production by linking with the smart seedling integrated management system. However, there is still a lack of standardization of seedling standards and quality for each vegetable crop to establish smart seeding production technology, as well as development of smart seedling production element technology, which requires national wide R&D support.