• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.677-685
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• 2005

Life Cycle Assessment(LCA) and Design for Environment(DfE) method were applied to design the environmentally sound manufacturing process of f31k lift in this study. Not only external movement of LCA and DfE method in the legal and systemic phase, but also active researches of those in the development phase of case study and application to the industrial field, have been going on. In concretely, the manufacturing processes of the folk lift generating the most environmental impact were examined by applying LCA method, and the environmentally sound manufacturing process was designed by applying, DfE method to the processes. As the results of LCA, environmental impacts for the eco-toxicity and human toxicity of seven major environmental categories were in high value, and so be in the cutting & welding process and painting process among the manufacturing processes. High solid paints, increasing the solid content of the existing solvent paints used in painting process, were developed to reduce the environmental impacts generated in the painting process. By utilizing the high solid paints, about 20% of environmental impacts (as environmental index of LCA) could be reduced.

• The Journal of the Acoustical Society of Korea
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• v.40 no.1
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• pp.46-54
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• 2021

In this paper, active noise control was performed to reduce radiated noise in the low frequency band of dishwashers. First, through an analysis of the noise environment of the dishwasher, it was confirmed that the pump noise contributed the most to the radiated noise in the low frequency band, From the result of the noise environment analysis, the reference signal was selected to be the vibration signal of the pump body. The reference signal was obtained by using the accelerometer on the pump body, which can prevent acoustic feedback. The error signal sensor was selected as a microphone located at 1 m in front of the dishwasher and 0.5 m in height. And to design the controller, the error signal and the reference signal were measured at the operational rpms of the dishwasher at 2,500 rpm, 2,600 rpm and 2,800 rpm, and the secondary path transfer function was measured. The designed controller was mounted on Digital Signal Processor (DSP) equipment, and the control performance was verified experimentally. As a result of the measurement at the 3 operational rpms, the 7th multiple component of pump operating frequency decreased by 1.93 dB, 4.43 dB, 5.15 dB per rpm, and the 12th multiple component decreased by 6.67 dB, 2.34 dB, 4.28 dB per rpm. And overall Sound Pressure Level (SPL) decreased by 0.84 dB, 2.58 dB, 1.48 dB by rpm.

• Journal of Welding and Joining
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• v.32 no.6
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• pp.22-28
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• 2014

Most publications on friction stir welding describe phenomena or results with given process parameters like feed rate, rotation speed, angle and depth of penetration. But without a complete documentation of tool design, the results under the same process parameters are completely different. For this purpose, the Institute of Cutting and Joining Manufacturing Processes (tff), University of Kassel investigated the influence of tool roughness on the friction stir welding process. Therefore a defined surface finish was produced by turning and die sinking. As basis of comparison the constant parameters were rotation speed, feed rate, tilt angle and a heel plunge depth. Sound butt-welds were produced in aluminium alloy 6082 (AlMgSi1) with 1.5 mm sheet thickness with a turned reference tool with a surface of $Ra=0.575{\mu}m$ in position controlled mode. The surfaces are manufactured from a very fine to a very rough structure, classified by the VDI-classes with differences in the arithmetical mean roughness. It can be demonstrated with the help of temperature measures, that less heat is generated at the surfaces of the shoulder and the pin by the higher roughness due to lower active friction contact surface. This can also be seen in the resulting wormhole defects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.570-575
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• 2019

Active muffler is implemented by applying active noise control technique to reduce exhaust noise of automobile muffler. Conventional Filtered_x LMS algorithm has a problem that the degree of control filter becomes very large and convergence deteriorates when acoustic feedback is present. The recursive LMS algorithm can compensate for this problem because it can be easily diverted in the adaptive filter adaptation process. In this paper, the structure of the primary path and the secondary path transfer function is designed as the IIR filter to improve the convergence performance and the computational burden, and the stabilization filter algorithm is applied to secure stability which is a disadvantage of the IIR filter structure. The stabilization filter algorithm plays a role of pulling the pole into the unit circle to prevent the pole of the transfer function corresponding to the acoustic feedback from diverging during the adaptation process. In this way, the computational burden of the active muffler system and the convergence performance can be improved. In order to show the usefulness of the proposed system, we compared the performance of the proposed Filtered_x LMS algorithm with the performance of the proposed system for the exhaust sound of a diesel engine, which is a variable environment. Compared to conventional algorithm, proposed algorithm's computational burden is less than half, and convergence performances are more than 4 times.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.6
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• pp.1161-1166
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• 2017

Recently, with the development of display technology, AMOLED(Active Matrix OLED) panel production and demand are increasing. Unlike LCD, AMOLED panel basically does not need backlight, so it can output clear images with low power consumption. Therefore, the AMOLED market is growing globally. Accordingly, the demand for inspection devices required for production is also expanding. The inspection device of the AMOLED panel aging system operates in conjunction with MES(Manufacturing Execution System) and MIS(Management Information System), and it is efficient to construct network environment. The inspection device used for panel aging is a pattern generator capable of outputting multiple signals. Efficient design is required to operate multiple signal generators. To solve this problem, the proposed system proposed a method for remotely controlling the signal generator remotely and a method for driving the AMOLED panel. And the timing and power setting results are presented.

• Korean Institute of Interior Design Journal
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• v.22 no.3
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• pp.154-163
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• 2013

Current principles of designating a smoking area within a non-smoking area rely on mere compartmentalization. This causes non-smokers aversion against smokers and smokers complaints about anti-smoking policies, which means both of them are not satisfied with the current scheme. In addition, such a system, far from the original intent of the law, does not provide appropriate respect for people's rights. The biggest problem of the current scheme is that smoking areas are not separated from non-smoking areas. Japan has continued installing independent smoking areas since 2002 and witnessed a decrease in the smoking rate. The country's success is attributable to: the state's active intervention in connection with enterprises; continuous environmental improvements and creation of goods; 'smoking etiquette' campaigns; and the sociality and group consciousness of Japanese people. It is recognized that the synergy of the designation of independent smoking areas and such multi-faceted efforts has led to the nation's accomplishment. Hence, it is required to install independent smoking areas in non-smoking areas in Seoul in order to respect the rights of smokers and non-smokers and resolve conflicts between them. It is not suitable to merely model after Japan's case, however, studies and guidelines that are tailored to Korea's own environment and social atmosphere are required. To ensure that the people recognize the necessity for smoking areas, a social consensus is formed and proper smoking areas are established in a systemic manner, a system for that purpose should connote a symbol of the social consensus and consequent guidelines should take physical elements, human activities and semantic assignment into consideration. This study aims to present basic guidelines to install separated smoking areas, which will keep distance between smokers and non-smokers, form a social consensus and establish a sound smoking culture. These would ensure that the rights of both smokers and non-smokers are fully respected and that government policies are trusted by the people.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.531-539
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• 2014

Recent studies of multiple participatory interactive media designs hows that the key element to this area is the participation of the audience. Due to this matter, this paper discusses the categories of the phase and looks into the characteristics of participatory matters to clarify the distinction. The categories that has been mentioned in this paper are multiple participatory types and active participatory types. Based on this matter, research practicing the Mira has been conducted in two separate groups - video and sound, and suggests the solution to the problems that has occurred during the process of implementing the final video system called 'The 360 Project'. The fact that the paper suggests a small range of participatory categories and hasn't come up with a certain analysis to the final outcome appears as a limit. The inadequacy will be supplemented throughout the following paper, hoping there will be improved versions of multiple participatory researches.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.7
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• pp.604-611
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• 2004

It is well known that wall impedance essentially determines how sound wave transmits from one place to another. The wall impedance is related with its dynamic properties : for example, the mass, stiffness, and damping characteristics. It is noteworthy, however, that the wall impedance is also function of spatial characteristics of two spaces that is separated by the wall. This is often referred that the wall is not locally reacting. In this paper, we have attempted to see how the acoustic characteristics of the two spaces is affected by various structure parameters such as density, applied tension, and a normalized length of the wall. Calculations are conducted for two different modally reacting boundary conditions by modal expansion method. The variation of the Helmholtz mode and the structural-dominated mode are analyzed as the structure parameters vary. The displacement distribution of the structure, pressure and active intensity of the inside and outside cavity are presented at the Helmholtz mode and the structure-dominated mode. It is shown that the frequency characteristics are governed by both structure-and fluid-dominated mode. The results exhibit that the density of the structure is the most sensitive design parameter on the frequency characteristics for the coupling system as we could imagine in the beginning. The Helmholtz mode frequency decrease as density increases. However. it increases as applied tension and an opening size increase. The bandwidth of the Helmholtz mode is mainly affected by density of the structure and its opening size.

• Journal of Wetlands Research
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• v.22 no.1
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• pp.31-38
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• 2020

Weirs are to secure amount water of streams and drop structures are to enhance stabilization of stream bed and bridges are to connect isolated region, which are called stream crossing structures. In the stream design criteria, directions for minimum size of structures are suggested to secure stability of stream crossing structures. However the sizes of almost all existing weirs and drop structures are not satisfied with the stream design criteria and only 22 percent of the peirs of bridges are satisfied. To enhance hydraulic stability of existing weirs and drop structures, it is required that the ratio of bed protection to apron should be above 3.3. According to factual survey of structures in the sample streams, it has been shown that the longitudinal slope of rapid works with 1:20 is the most reasonable to design velocity if existing weirs and drop structures are rehabilitated into rapid works. It has been known that violating freeboard and span length of piers should make existing bridges reconstructed or removed. However, comprehensive review including deterioration level of bridges, special regulation for span length, etc. should be considered to determine rehabilitation plan of bridges. In this study, a procedure has been suggested to improve hydraulic stability of weirs, drop structures and piers of bridges. Sound environment of stream and reduction of natural disaster could be achieved by improving stability of cross structures, which could be obtained by governmental budget and active stream management including observance of design criteria.

• Journal of Korean Medical Ki-Gong Academy
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• v.20 no.1
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• pp.15-67
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• 2020

Objective : The purpose of this study is to identify the trends of vibration(or wave) therapy in Korea, to actively utilize vibration(or wave) therapy, and to help research activities of vibration therapy in Korean Medicine. Methods : The following Korean words "진동기", "진동요법", "진동운동", "진동치료", "파동요법", "파동운동", "파동치료" were searched on three specialized search sites (RISS, NAL, DBpia). Trends of vibration therapy were analyzed through the selected researches suitable for this study among these searched researches in an overview format. Results : 1. A total of 8,116 studies were searched and a total of 365 studies were finally selected 2. From 2000 to 2019, when research began to increase in earnest, there were 17.45±10.28 studies per year, and the AGR(Average Annual Growth Rate) was 11.92%. 3. In the main field of research, the 'Medicine and Pharmacy' was the largest with 147(40.16%) studies. In the Middle Field, the 'Kinesiology' was the largest with 99(27.05%) studies. In the study design, 'RCT(Randomized Controlled trial)' was the largest with 138(47.75%) studies. In the Age Group, 'Youth' was the largest with 126(48.84%) studies. 4. The average of the number of participants was 24.90±17.44. 5. The most used Intervention was the 'WBV(Whole Body Vibration)' with 177(61.25%) studies. 6. The average of Intervention Period was 5.99±4.14 weeks, while the maximum was 36 weeks. 7. The journal that published the most research papers is 'K. J. of Sports Science(체육과학연구;13)', and the society is 'Rehabilitation Engineering And Assistive Technology Society of Korea(한국재활복지공학회; 14)'. The University that published the most dissertations is 'Sahmyook University(11)'. 8. The authors who published the most studies are Ju-Hwan O(8) as the main author and Tae Kyu Kwon(18) as the co-author (including the thesis Director). In an integrated analysis of the authors and co-authors, Tae Kyu Kwon published the most numerous studies(19) Conclusions : 1. The study of vibration or wave therapy has been increasing noticeably every year. 2. The major academic Fields studying vibration or wave therapy are the 'Kinesiologic Field', 'Physical Therapy Field', and 'Biomedical Engineering Field'. 3. The most chosen method of study design on vibration or wave treatment was 'RCT', and there was no significant change in the annual presentation rate. 4. Types of vibration or wave therapy could be classified as 'LVS(Local Vibration Stimulation)', 'WBV(Whole Body Vibration)', 'MV(Micro Vibration)', 'BV(Bio Vibration)' and 'SWV(Sound Wave Vibration)', and the study on Whole Body Vibration is most active. 5. Most of the studies of vibration or wave therapy were on musculoskeletal systems, but there were very few studies on internal diseases.