• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.641-646
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• 2016

The effects of water addition on $Y_2O_3$ coatings or thick films prepared by plasma suspension spray (SPS) have been investigated. Water addition in suspension media was found to be effective to control the color of a $Y_2O_3$ coating prepared by SPS. The color changed with water addition at the shortest stand-off distance of 50 mm even if samples had the same crystalline phase. Change was not correlated with fragmentation behavior of liquid suspension inside the plasma jet. Water content over 50 vol% was found to produce unmelted particles, indicating that water suppressed heat transfer to the particles. However, plasma jet temperature was not affected. Instead, the coating fabricated with water addition has higher oxygen and lower carbon content compared to these characteristics of the coating without water addition. This was attributed to the retarded complete evaporation of liquid media from the suspension droplet, resulting in inhibition of excessive heating and evaporation of the molten $Y_2O_3$ droplet. In this regard, crystalline phase development with respect to stand-off distance and water addition was discussed.

• Journal of Convergence for Information Technology
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• v.7 no.4
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• pp.39-43
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• 2017

The purpose of this study was to investigate of effect of medial & inferior gliding of patella using non-elastic taping on muscle activation of vastus medialis & vastus lateralis during sit to st&ing. As a result of measure, it was confirmed that the muscle activity of vastus medialis is higher than total muscle activity when the inferomedial gilding compared to the medial gliding. The medial & downward gliding of patella more stable than medial direction. especially it will be effective on prevent or control of Patellofemoral pain syndrome. In this regard, the development of orthosis & sportswear for inferomedial gliding to patella will be efficiency to maintain healthy the knee joint.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.168-176
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• 1989

Recent development of geographic information systems(GIS) provides a great deal of potential in handling a variety of spatial data required by forest resource managers. This study is designed to identify a possible GIS application in forest pest management. Several mountain pine beetle risk assessment parameters(stand characteristics, weather conditions, and topographic factor) were spatially analyzed through computer map overlaying operations in order to estimate the hazard level of the pest damage. In addition, the expected infestation route from an initially infected forest stand was located through further may analysis operations(distance measurement and connectivity analysis). Although current GIS technology may have a few limitations in operational situations, the computer based GIS has been proven as an invaluable tool to resource managers by providing flexible spatial data handing capabilities.

• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.74-83
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• 2019

This study designs a squat posture recognition system that can provide correct squat posture guidelines. This system comprises two modules: a Kinect camera for monitoring users' body movements and a Wii Balance Board(WBB) for measuring balanced postures with legs. Squat posture recognition involves two states: "Stand" and "Squat." Further, each state is divided into two postures: correct and incorrect. The incorrect postures of the Stand and Squat states were classified into three and two different types of postures, respectively. The factors that determine whether a posture is incorrect or correct include the difference between shoulder width and ankle width, knee angle, and coordinate of center of pressure(CoP). An expert and 10 participants participated in experiments, and the three factors used to determine the posture were measured using both Kinect and WBB. The acquired data from each device show that the expert's posture is more stable than that of the subjects. This data was classified using a support vector machine (SVM) and $na{\ddot{i}}ve$ Bayes classifier. The classification results showed that the accuracy achieved using the SVM and $na{\ddot{i}}ve$ Bayes classifier was 95.61% and 81.82%, respectively. Therefore, the developed system that used Kinect and WBB could classify correct and incorrect postures with high accuracy. Unlike in other studies, we obtained the spatial coordinates using Kinect and measured the length of the body. The balance of the body was measured using CoP coordinates obtained from the WBB, and meaningful results were obtained from the measured values. Finally, the developed system can help people analyze the squat posture easily and conveniently anywhere and can help present correct squat posture guidelines. By using this system, users can easily analyze the squat posture in daily life and suggest safe and accurate postures.

• Journal of Digital Convergence
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• v.19 no.4
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• pp.73-88
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• 2021

The development of modern industry is changing the consumption pattern of consumers. With the advent of COVID-19, consumers' consumption using online e-commerce has begun to become more active. Online shopping malls where e-commerce takes place have four types of platforms: stand-alone, rental, open market and store farm. Among them, by comparing the stand-alone and store farm types, this study was conducted how the platform type affects consumers' purpose of using the online shopping mall and their intention to revisit the online shopping mall. This study analyzed 202 surveys within the last six months. According to the results of the study, reliability and information had a significant impact on psychological benefits. In addition, promotion and convenience have had a significant impact on economic benefits. The psychological and economic benefits, have been found to have a significant impact on the intention of revisit. However, there is no difference depending on the platform type.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.600-602
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• 2021

With the development of the mobile industry and growing interest in artificial intelligence (AI) technology, a lot of research for AI processors which applicable to embedded systems is under study. When implementing AI to embedded systems, the design should be considered the restriction of resource and power consumption. Moreover, it is efficient to include a dedicated hardware accelerator in order to complement the low computational performance of the embedded system. In this paper, we propose an stand-alone embedded AI processor. The proposed AI processor includes a hardware accelerator that is dedicated to the distance-based AI algorithm and a general-purpose MCU that supports flexible programmability for application to various embedded systems. The AI processor was designed with Verilog HDL and verified by implementing on Field Programmable Gate Array (FPGA).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.2
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• pp.293-303
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• 2002

Recently, the use of the high strength materials and development of construction techniques have resulted in more flexible and longer spanning in the stadium systems. So the natural frequency of stadium structures are became low. Stadium stand could be led to significant dynamic response as like resonance due to spectator rhythmical activities. The accurate analysis of dynamic behavior of stadium systems and the precise investigation of the dynamic loads on stadium structures are demanded for effective design. It is desirable to apply measured dynamic loads created by spectator activities because these dynamic loads are not easy to express numerical formula. As the floor mesh of stadium stand is refined, the number of divided elements increases in numerical analysis. the rise of the number of elements makes the numbers of nodal points increased and numerous computer memory required. So it is difficult to analysis refine full model of stadium structures by using the commercial programs. In this study, the various dynamic loads induced by spectator movements are measured and analyzed. And a new modeling method that reduce the nodal points are introduced. Vibration analysis of stadium stands is executed to inspect accuracy and efficiency of proposed method in this paper.

• Journal of Korean Society of Forest Science
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• v.106 no.2
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• pp.267-273
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• 2017

This study was conducted to construct a empirical yield table for Pinus densiflora in real forest. Since existing normal yield tables have been derived by studying and analyzing communities in ideal environment for tree growth, those tables provide more over-estimated values than ones from real forest. Because of this, there are some difficulties to apply the tables to empirical forest except for normal forest. In this study, therefore, we estimated stand growth for real forest on P. densiflora as the representative species of conifers. We used 1,957 sample plot data of P. densiflora in central Korea from National Forest Inventory (NFI) system, and analyzed through estimation, recovery and prediction in order by using Weibull function as a diameter distribution model. Weilbull and Schumacher models were applied for estimating mean DBH and mean basel area and it was found that the site index for P. densiflora in central Korea ranges from 8 to 14 at reference age 30. According to site 12 in the stand yield table, the Mean Annual Increment (MAI) of P. densiflora was $4.42m^3/ha$ at 30 years of age. Compared to existing volume table constructed before, it is showed that MAI of this study were lower. According to the paired t-test that is conducted with the gap of volume values between normal forest and real forest by site index and age, the P-value was less than 0.001 which is recognized to have a statistically significant difference. Based on the results in this study, it is considered to be helpful for practical management and management policy on P. densiflora in central Korea.

• Fire Science and Engineering
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• v.24 no.4
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• pp.18-26
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• 2010

The change of fuel moisture according to the passed days after a raindrop is very important to forecast risk of forest fire and to make a good use of forest fire watchmen. For that reason, in the Spring of 2007, we researched pine forest that were widespread growing in Yeongdong region to find out the condition of forest fire risk. We developed the forecast model of fuel moisture change on dead tree branches which were dropped on the ground and less than 0.6 cm, 0.6~3.0 cm, 3.0~6.0 cm, and more than 6.0 cm in diameter after more than 5.0 mm in precipitation. The result showed that the less diameter of ground fuel and small stand of pines the faster diminishing of fuel moisture, and the days of reaching to a forest fire danger fuel moisture level were represented by two (2) days for less than 0.6 cm diameter of small stand of pine and three (3) days for 0.6~3.0 cm diameter one, respectively. By those results, we developed the forecast model($R^2=0.76{\sim}0.92$) of fuel moisture change on different diameter of small stand of pine, and found that the model had statistical significant of 1% level after we applied it to the data of 2008 after the same period of raindrop by actual meteorological measurement.

• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.197-205
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• 2013

In this study, we developed a program of optimizing stand-level carbon stock using a stand-level yield model and the Simulated Annealing (SA) heuristic method to derive a optimized forest treatment solution. The SA is one of the heuristic algorithms that can provide a desirable management solution when dealing with various management purposes. The SA heuristic algorithm applied 'thermal equilibrium test', a thresholds approach to solve the phenomenon that does not find an optimum solution and stays at a local optimum value during the process. We conducted a sensitivity test for the temperature reduction rate, the major parameter of the thermal equilibrium test, to analyze its influence on the objective function value and the total iteration of the optimization process. Using the developed program, three scenarios were compared: a common treatment in forestry (baseline), the optimized solution of maximizing the amount of harvest(alternative 1), and the optimized solution of maximizing the amount of carbon stocks(alternative 2). As the results, we found that the alternative 1 showed provide acceptable solutions for the objectives. From the sensitivity test, we found that the objective function value and the total iteration of the process can be significantly influenced by the temperature reduction rate. The developed program will be practically used for optimizing stand-level carbon stock and developing optimized treatment solutions.