• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.449-455
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• 2010

Implantable middle ear hearing devices(IMEHDs) have being actively studied to overcome the problems of conventional hearing aids. Vibration transducer, an output devices of IMEHDs, is attached on the ossicular chain and transmits mechanical vibration to cochlea. This approach allows us to hear more clear sound because mechanical vibration is effective to transfer high frequency acoustics, but occurs some problems such as fatigue accumulation to ossicular chian and reduction of vibration displacement caused by mass loading effect. Recently, many studies for the round window stimulation are announced, because it does not cause such problems. It have been studied by older transducers designed for attaching on ossicular chain. In this paper, we proposed a new electromagnetic transducer which consists of two magnets, three coils and a vibration membrane. The magnet assembly, magnet coupled in opposite direction, were placed in the center of three coils, and the optimum length of each coil generating maximum vibrational force was calculated by finite element analysis(FEA). The transducer was implemented as the calculated length of each coil, and measured vibration displacement. From the results, it is verified the vibration displacement can be improved by optimizing the length of coils.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.9
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• pp.1144-1151
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• 2021

The pressing process is a compression process in which a product is made by applying force to a heated or unheated material to transform it into the desired shape. Due to the characteristics of press equipment that produces products through continuous compression for a short time, product defects occur continuously, and systems for solving these problems are being developed using various technologies. This paper proposes a real-time defect detection system based on an artificial intelligence algorithm that detects defects. By attaching various sensors to the press device, the relationship between equipment status and defects is defined and collected based on a big data platform. By developing an artificial intelligence algorithm based on the collected data and implementing the developed algorithm using an embedded board, we will show the practicality of the system by applying it to the actual field.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.76-83
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• 2023

Squatting of agricultural work can cause musculoskeletal disorders due to excessive pressure and rotational force on the knee joint In order to improve the assistive chair used in squatting agricultural work so that it can be used in a narrow groove, it is intended to improve the musculoskeletal harm of squatting work by attaching a spring on the assistive chair. Therefore, in the presenty study, 3D drawing was done using ProEngineer (3D), and a mock-up was produced and tested. Using pro-Engineer, it was judged that it was rare for plastic to be broken by a spring, so the analysis was conducted with a focus on springs. It was found that the structure that can absorb the shock according to the rigidity of the tape spring and balance the body is that the power to withstand the load of the weight is distributed as a whole when five springs are used. Electromyography was measured using ME600 (Mega Electronics, Finland) Measuring equipment attached to the waist, thighs, calves, and shins. EMG values were measured and compared with the prototype in two ways, when the worker did not wear the product and when he wore an existing product on the market. As a result of the experiment when using the prototype, the maximum EMG value for each part is considered to be helpful in preventing musculoskeletal diseases as the amount of muscle used is reduced in the waist, thighs, calves, and shins.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.437-447
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• 2011

In this study, the lower limbs joints were analyzed for features based on the biomechanical characteristics of landing techniques according to height and landing on the ground type (flats and downhill). In order to achieve the objectives of the study, changes were analyzed in detail contents such as the height and form of the first landing on the ground at different angles of joints, torso and legs, torso and legs of the difference in the range of angular motion of the joint, the maximum angular difference between joints, the lower limbs joints difference between the maximum moment and the difference between COM changes. The subjects in this study do not last six months did not experience joint injuries 10 males in 20 aged were tested. Experimental tools to analyze were the recording and video equipment. Samsung's SCH-650A model camera was used six units, and the 2 GRF-based AMTI were used BP400800 model. 6-unit-camera synchronized with LED (photo cell) and Line Lock system were used. the output from the camera and the ground reaction force based on the data to synchronize A/D Syc. box was used. To calculate the coordinates of three-dimensional space, $1m{\times}3m{\times}2m$ (X, Y, Z axis) to the size of the control points attached to the framework of 36 markers were used, and 29 where the body was taken by attaching a marker to the surface. Two kinds of land condition, 40cm and 60cm in height, and ground conditions in the form of two kinds of flat and downhill slopes ($10^{\circ}$) of the landing operation was performed and each subject's 3 mean two-way RM ANOVA in SPSS 18.0 was used and this time, all the significant level was set at a=.05. Consequently, analyzing the landing technique as land form and land on the ground, the changes of external environmental factors, and the lower limbs joints' function in the evaluation were significantly different from the slopes. Landing of the slop plane were more load on the joints than landing of plane. Especially, knee extensor moment compared to the two kinds of landing, slopes plane were approximately two times higher than flat plane, and it was statistical significance. Most of all not so much range of motion and angular velocity of the shock to reduce stress was important. In the further research, front landing as well as various direction of motion of kinetic, kinetic factors and EMG variables on lower limbs joints of the study in terms of injury-prevention-approach is going to be needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.692-696
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• 2017

The shape of press components is becoming increasingly complex due to customer demands, process shortening and cost savings. In addition, the stability of the pressing process frequently varies during mass production due to the influence of many factors. In order to ensure the process stability, it is necessary to establish a process in which reproducibility is realized in tolerance, which is sufficient for advance study of shape, material, press, mold and lubrication. However, unforeseen changes in process parameters cause disruptions in production line shutdowns and production planning. In this paper, we introduce a method to monitor a real time process by applying a sensor to a press mold. A non-contact type sensor for measuring the flow of a sheet material and an example of an experiment using the optical sensor which is highly applicable to mass production are presented. An optical sensor was installed in a cylindrical drawing mold to test its potential application while changing the material, blank holder force, and drawing ratio. We also quantitatively determined that the flow of other sheet materials was quantified locally using a square drawing die and that the measured value was always smaller than the drawing depth due to the material elongation. Finally, we propose a field that can be used by attaching the sensor to the press mold. We hope that the consequent cost reduction will contribute to increasing global mold competitiveness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.493-503
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• 2018

Recently, as living standards have improved, many people are becoming more interested in health, and self-training is increasing through exercise to prevent and manage pre-illness. In general, an imbalance of muscles causes asymmetry of posture, which can cause various diseases by accompanying an adjustment force, circulation action, displacement of internal organs, etc.. In this study, the development of fitness software that can be self - training among smart wears has attracted considerable attention in recent years. In this study, a technology was proposed for the commercialization of self - trainer fitness wear by a simulation through Android - based applications. Self - trainer fitness software was developed by combining a conductive polymer, fashion design, sewing, and electric and electronic technology to monitor the unbalance of the muscles during exercise and make smart wear that can calibrate the asymmetry by oneself. In particular, a polymer sensor was fabricated by deriving the optimal MWCNT concentration, and the electrode signal was collected by attaching the electrode to the optimal position, where the electrode signal line using the conductive fiber was designed and attached to collect the signal. A signal module that converts the bio-signals collected through electrical signal conversion and transmits them using Bluetooth communication was designed and manufactured. Self-trainer fitness software that can be commercialized was developed by combining noise cancellation with Android-based self-training application using a software algorithm method.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.35-40
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• 2022

In the agricultural environment, pesticide control requires a high risk of work and a high labor force for farmers. The effectiveness of pesticide control using unmanned aerial vehicles varies according to climate, land type, and characteristics of unmanned aerial vehicles. Therefore, an effective method for pesticide control by unmanned aerial vehicles considering the spraying conditions and environmental conditions is required. In this paper, we propose an efficient pesticide control system based on agricultural unmanned aerial vehicles considering the application conditions and environmental information for each crop. The effectiveness of the proposed model was demonstrated by measuring the drop uniformity of pesticides according to the change in altitude and speed after attaching the sensory paper and measuring the penetration rate of the drug inside the canopy according to the change in crop growth conditions. Experiment result, the closer the height of the UAV is to the ground, the more evenly the crops are sprayed, but for safety reasons, 2m more is suitable, and on average a speed of 2m/s is most suitable for control. The proposed control system is expected to help develop intelligent services based on the use of various unmanned aerial vehicles in agricultural environments.

• KDI Journal of Economic Policy
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• v.13 no.1
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• pp.115-134
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• 1991

The role of pension plans in the macroeconomy has been a subject of much interest for some years. It has come to be recognized that pension plans may alter basic macroeconomic behavior patterns. The net effects on both savings and labor supply are thus matters for speculation. The aim of the present paper is to provide quantitative results which may be helpful in attaching orders of magnitude to some of the possible effects. We are not concerned with the providing empirical evidence relating to actual behavior, but rather with deriving the macroeconomic implications for a alternative possibilities. The pension plan interacts with the economy and the population in a number of ways. Demographic variables may thus affect both the economic burden of a national pension plan and the ability of the economy to sustain the burden. The tax transfer process associated with the pension plan may have implications for national patterns of saving and consumption. The existence of a pension plan may have implications also for the size of the labor force, inasmuch as labor force participation rates may be affected. Changes in technology and the associated changes in average productivity levels bear directly on the size of the national income, and hence on the pension contribution base. The vehicle for the analysis is a hypothetical but broadly realistic simulation model of an economic- demographic system into which is inserted a national pension plan. All income, expenditure, and related aggregates are in real terms. The economy is basically neoclassical; full employment is assumed, output is generated by a Cobb-Douglas production process, and factors receive their marginal products. The model was designed for use in computer simulation experiments. The simulation results suggest a number of general conclusions. These may be summarized as follows; - The introduction of a national pension plan (funded system) tends to increase the rate of economic growth until cost exceeds revenue. - A scheme with full wage indexing is more expensive than one in which pensions are merely price indexed. - The rate of technical progress is not a critical element in determining the economic burden of the pension scheme. - Raising the rate of benefits affects its economic burden, and raising the age of eligibility may decrease the burden substantially. - The level of fertility is an element in determining the long-run burden. A sustained low fertility rate increases the proportion of the aged in total population and increases the burden of the pension plan. High fertility has inverse effects.