• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.83-91
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• 2022

Purpose: The goal of this study was to investigate changes in dual-task performance according to age and difficulty of cognitive tasks for the in community-dwelling elderly populations, as well as to examine their changes in hand dexterity according to age and cognitive function. Methods: A total of 135 people aged 65 years old and over participated in the study. To evaluate each participant's dual-task performance, each participant completed a dual task. To assess their cognitive function, the Korean Mini-Mental State Examination (MMSE-K) and the Korean version of Montreal Cognitive Assessment (MoCA-K) were the tools used. Participants were divided into three groups based on their age: 65-69 years, 70-79 years, and 80-89 years. Results: The findings showed that age groups and the difficulty of the cognitive task significantly affected the amount of time required for dual-task performance (p<.001). Additionally, the dual-task correct response rate (CRR) decreased significantly with age groups and the difficulty of the cognitive task (p<.001). The amount of time required for finger dexterity performance increased significantly with age groups (mean score±standard deviation [SD]; 19.46±2.26 in subjects aged 65-69 years; 21.92±2.61 in subjects aged 70-79 years; and 23.82±2.92 in subjects aged 80-89 years; p<.001). Moreover, as a result of the correlation between hand dexterity and cognitive function, MoCA-K was -0.563 and MMSE-K was -.412, showing a statistically significant correlation (p<.001). Conclusions: Age and the difficulty of the cognitive task affect the community-dwelling elderly populations in terms of dual-task performance and dual-task CRR. In addition, aging and general cognition have an impact on hand dexterity. Based on the results of this study, it is anticipated that the results will serve as a reference for domestic clinical trials that confirm cognitive decline in the elderly using dual task and hand dexterity evaluation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1036-1043
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• 2014

The installation of PV system to the power distribution system is being increased as one of solutions for environmental pollution and energy crisis. Because the output efficiency of PV system is getting decreased because of the aging phenomenon and several operation obstacles, the technology development of output prediction and state diagnosis of PV modules are required in order to improve operation performance of PV modules. The conventional methods for output prediction by considering various parameters and standard test condition values of PV modules may have difficult and complex computation procedure and also their prediction values may produce large error. To overcome these problems, this paper proposes an optimal prediction algorithm and state diagnosis algorithm of PV modules by using least square methods of linear regression analysis. In addition, this paper presents a state diagnosis evaluation system of PV modules based on the proposed optimal algorithms of PV modules. From the simulation results of proposed evaluation system, it is confirmed that the proposed algorithms is a practical tool for state diagnosis of PV modules.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.77-82
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• 2020

As Korea enters an aging age, social efforts to improve the IADL of the elderly are increasing. In this study, to improve the performance of financial management activities that the elderly is particularly burdened, we aim to learn the elderly through ATM simulation education contents so that they can use ATM smoothly. To this end, interviews were conducted with seniors to derive four major financial activities (deposits, withdrawals, deposit inquiries and bank account arrangements), and developed tablet PC-based ATM education contents identical to the existing bank ATM interfaces. The experiment was conducted on 20 elderly people in the Elderly Day Care Center, and their satisfaction, fatigue and performance were measured before and after education. The results of this study can provide ATM design guidelines for the elderly who have difficulty using ATM.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.241-246
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• 2019

In this study, we have examined the possibility to improve the material properties and biocompatibility of the 630 stainless steel for the application of medical instruments. The evaluation of mechanical properties and biocompatibility of the 630 stainless steel were studied by aging, nitriding, SEM measurement, Vicker's hardness, tensile strength and MTT cytotoxicity using IGF cells, respectively. The results showed that the tensile strength and Vicker's hardness of 630 stainless steel was increased with aging and ion nitriding time. The cytotoxicities of the 630 stainless decreased compared with the 420 stainless on MTT cytotoxicity using IGF cells. Ion nitriding of 630 stainless led to an enhanced application of medical instruments and biocompatibility performance.

• Journal of the Ergonomics Society of Korea
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• v.36 no.1
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• pp.53-67
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• 2017

Objective: The purpose of this study is to build basic data to systematically develop a hand function evaluation tool by determining the effects of age, gender and target force level on the difference in hand function according to the target force level. Background: Precise and objective evaluation of hand functionality is a very important factor in quantifying treatment progress in patients or elderly people, and in verifying treatment effects. However, most hand function evaluations lack objectivity and accuracy, and therefore it is difficult to properly treat patients according to the given situation. Method: Sixteen healthy subjects (eight elderly and eight young people) participated in this study to evaluate the effects of age, gender, and target force level on tracking performance through rRMSE in terms of the tracking force and actual exerted force, by carrying out a task of maintaining six different target force levels for 20 seconds. Results: The result of this experiment indicated that elderly people and women had a lower ability to maintain a certain level of force than young people and men by 16% and 10%, respectively. The target force level results showed that the tracking error of the lowest force level (5% MVC) was significantly higher than that of 15% MVC, which in turn showed a higher tracking error than that of the higher target force levels. Conclusion: The results of this study can thus be utilized to develop a rehabilitation program for elderly people or other patients. Application: The authors expect that the results of the present study will be valuable to develop a rehabilitation program and hand function evaluation tool.

• Journal of Korean Society of Archives and Records Management
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• v.22 no.4
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• pp.25-43
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• 2022

The ultimate record management's purpose is preservation and utilization. However, the National Archives of Korea (NAK)s Portal has problems such as search system aging and search tools dualization. As a result, the users' search satisfaction is not satisfied, and the improvement demand increases. This study aimed to evaluate the NAK's search quality as a preliminary study for NAK search system advancement. To this end, we analyzed the current status of CAMS and NAK's Portal. Then, we established the test sets and evaluated the NAK's Portal quality from the user's point of view. Evaluation results were analyzed using Precision, Recall, F-score, and MRR. The analysis results showed that the overall search performance was low, particularly in the "advanced subject search," which showed low performance in Precision, Recall, and MRR. Thus, improvement is urgently needed. The test sets established for this study are expected to be used as a basis for objectively measuring the improvement of the search performance after the NAK search system advancement.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.411-419
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• 2020

Purpose: This study is intended to improve the performance of traffic signs corroded by aging, to ensure maintenance efficiency, a water-hardened coating solution was developed. Performance tests were then used to determine the optimal component scale. Method: For research purposes, the results were analyzed by conducting corrosion resistance assessment, physical properties evaluation, storage safety assessment, etc. on coating solutions of various magnifications. Results: The analysis results showed that there was little hearing in the cutting area in the liquid with added magnesium, so the method effect was excellent. And there was little blister occurrence, which was analyzed at the highest magnification. Conclusion: Enhancements to future new component scale experiments are needed for water-hardened coating solutions that have been recognized for their performance through this study. And institutional improvement efforts are needed to expand the enforcement of traffic sign maintenance using coating solutions.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.1097-1102
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• 2022

With the continuous development of the current industry, the current global environment is in a very serious situation, with resource supply and demand dependent on imports and huge costs for waste disposal due to the depletion of resources and mass generation of industrial waste. Its limitations have already been revealed in many fields, and the importance of re-manufacturing is drawing attention as a countermeasure to these problems. Re-manufacturing aims to recover products that are in the aging and disposal stages, recover to performance close to new products, and re-commercialize them. Among them, most of the machine tools are made of materials such as steel and cast iron with large structures, and raw materials are widely used when producing new products. In addition, since a lot of carbon is generated due to production, it is an object that can obtain a great re-manufacturing effect. Planner millers belonging to large machine tools are one of the machine tool equipment that can greatly reduce resources and energy through re-manufacturing because the structure is very large and the casting is several to tens of tons. Through this machine tool, performance tests and results are derived on the development of re-manufacturing source technology and domestic servo motor and CNC control device.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.123-130
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• 2005

In this study, we evaluated the CH4 and CO conversion efficiencies over the oxidation catalysts for natural gas vehicle with lean-burn system. On the fresh catalyst, the conversion efficiency was increased when the loading of precious metal was increased. On the aged catalyst, the conversion efficiency was decreased as increasing the excess air ratio. We could confirm the measuring conversion efficiency of the unsteady state with the FTIR and that of steady state with the GC The temperature increasing ratio of unsteady state is acceptable from 3$^{\circ}C$/min. to 15$^{\circ}C$/min. for the evaluation of catalyst conversion performance , which has within the 4$\%$ of the difference of conversion efficiency. We observed a physical behavior of the thermal aged catalyst's surface using TEM and BET device. It was found that the precious metal was grown to the micro-scopic size by thermal aging process.

• Journal of the Korean Ceramic Society
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• v.56 no.6
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• pp.541-548
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• 2019

Zirconia (ZrO₂) materials are widely used in a variety of energy systems and devices. When nanorod-shaped ZrO₂ is used as energy materials, ionic conductivity and mechanical strength can be improved compared to the characteristics of conventional spherical-shaped nanomaterials. In this study, we synthesized ZrO₂ nanorods and investigated the shape change of them depending on various synthesis conditions such as precursor concentration, synthesis temperature, synthesis period, and aging period. The obtained nanorods were casted into a membrane for alkaline water electrolysis system and subjected to basic performance evaluation for use as a separator. The structure and the shape of the nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and the like.