• Journal of the Korean Institute of Gas
• /
• v.27 no.3
• /
• pp.11-18
• /
• 2023

This study explained the need for ammonia fuel and the value chain as a hydrogen carrier. The basic concept of ammonia combustion characteristics and the development of flame stability and low NOx combustion technology were introduced. In addition, through the trend of ammonia combustion technology, the characteristics of ammonia combustion technology in the power generation and industrial sectors were examined, and the author's opinions were included. Through this paper, the author intends to give some overview of basic knowledge about ammonia fuel and its future development direction and meaning.

• Journal of Convergence for Information Technology
• /
• v.9 no.6
• /
• pp.112-120
• /
• 2019

The purpose of this study is to explore educational methods for elementary, middle and high schools using school forests via IT convergence. To this aim, we reviewed the previous literature on education using school forests to identify the problems with the existing education using school forests, and conducted interviews with experts to analyze the demands. we proposed an educational method that can utilize the school forests via IT convergence, and explored its validity through content reviews conducted by experts. The findings of this study are as follows. First, we proposed the IT convergence instruction focused on hands-on activities on top of the existing educational contents. Second, we proposed IT convergence instruction that incorporates diverse materials, physical computing tools, and programming tools. Third, we presented methods for utilizing such IT convergence instruction in connection with various elements of the 2015 Revised Curriculum as well as with various other activities such as middle school free semester activities and after-school activities. The school forest is a crucial learning space for the areas related to agriculture and biotechnology. Thus, we anticipate that the IT convergence instruction proposed in this study will lead to the re-discovery and re-evaluation of a value of school forests as an educational space that contributes to fulfilling the objective of the 2015 Revised Curriculum to nurture creative convergent talent.

• Journal of the Korean Society of Radiology
• /
• v.13 no.1
• /
• pp.119-124
• /
• 2019

Radiation therapy using flattening filter free beam can prevent beam attenuation caused by flattening filter and can improve treatment efficiency. However, accurate dose control is not established for nonuniform iso dose distributions. In this study, curved dosimeter based on photoconductive material $HgI_2$ was fabricated and its reproducibility and linearity were evaluated at 6 MV photon energy to verify its performance. In order to show the usefulness of the curved measurement, the signals measured on the flat substrate and the curved substrate were compared in the flattening filter free beam using the acrylic filter. As a result, the reproducibility of the unit cell dosimeter was evaluated as SE 0.613%, and the linearity was evaluated as R-sq 0.9999. The usability evaluation of the array curve dosimeter demonstrated its usefulness by indicating a curvature error rate of 11.073%p and a reduced error rate.

• Journal of the Korea Convergence Society
• /
• v.13 no.5
• /
• pp.249-259
• /
• 2022

More than a year has already passed since the Gyeongbuk Hemp Regulation Free Zone Project was implemented, and it is time to supplement and review the deficiencies in production history management for the domestic hemp industry after the Free Regulatory Zone. In this study, the current status and characteristics of cannabis history management in the Gyeongbuk Hemp Regulation Free Zone project were investigated, and problems with current history management were derived using service design tools such as pilot interviews, shadowing, and Customer journey map. The case of the cannabis production system and the CTS recommended for the legal cannabis market in Oregon, a leading country, was compared and analyzed, and the direction was to secure safety through production cycle history management suitable for growth characteristics, efficient technology application for real-time management, and history information sharing. Through this study, it is expected that it will help improve the current hemp production history management system and properly settle the history management system of domestic hemp industrialization in the future.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.413-413
• /
• 2014

In this paper, we present a fabrication method of functionalized gold nanostructures on flexible substrate that can be implemented for plasmonic sensing application. For biomolecular sensing, many researchers exploit unconventional lithography method like nanoimprint lithography (NIP), contact transfer lithography, soft lithography, colloidal transfer printing due to its usability and easy to functionalization. In particular, nanoimprint and contact transfer lithography need to have anti-adhesion layer for distinctive metallic properties on the flexible substrates. However, when metallic thin film was deposited on the anti-adhesion layer coated substrates, we discover much aggravation of the mold by repetitive use. Thus it would be impossible to get a high quality of metal nanostructure on the transferred substrate for developing flexible electronics based transfer printing. Here we demonstrate a method for nano-pillar mold and transfer the controllable nanoparticle array on the flexible substrates without an anti-adhesion layer. Also functionalization of gold was investigated by the different length of thiol applied for effectively localized surface plasmonic resonance sensing. First, a focused ion beam (FIB) and ICP-RIE are used to fabricate the nanoscale pillar array. Then gold metal layer is deposited onto the patterned nanostructure. The metallic 130 nm and 250 nm nanodisk pattern are transferred onto flexible polymer substrate by bi-layer functionalized contact imprinting which can be tunable surface energy interfaces. Different thiol reagents such as Thioglycolic acid (98%), 3-Mercaptopropionic acid (99%), 11-Mercaptoundecanoic acid (95%) and 16-Mercaptohexadecanoic acid (90%) are used. Overcoming the repeatedly usage of the anti-adhesion layer mold which has less uniformity and not washable interface, contact printing method using bi-layer gold array are not only expedient access to fabrication but also have distinctive properties including anti-adhesion layer free, functionalized bottom of the gold nano disk, repeatedly replicate the pattern on the flexible substrate. As a result we demonstrate the feasibility of flexible plasmonic sensing interface and anticipate that the method can be extended to variable application including the portable bio sensor via mass production of stable nanostructure array and other nanophotonic application.

• The Journal of the Convergence on Culture Technology
• /
• v.4 no.1
• /
• pp.67-73
• /
• 2018

Financial plight condition firms difficulties accessing external funding, these firms will arrange scarce funds using tax avoidance can be a way of improvement of internal cash flow and internal funds securement. This study is empirical evidence presented the association between free cash flow can be represented for financial condition of firms and using tax avoidance for Kosdaq listed firms. Empirical analysis result, presented plus (+) results the association between free cash flow and tax avoidance. these results are in the previous year free cash flow is large firms purpose of internal cash holdings that increase of tax avoidance in order to minimize of cash outflow are based on tax burden. also interaction effect of free cash flow and debt ratio is presented influence of plus(+) on tax avoidance.

• Journal of Internet of Things and Convergence
• /
• v.9 no.2
• /
• pp.19-31
• /
• 2023

The importance of barrier free is being highlighted worldwide. This study attempted to identify barrier-free research trends using text mining. Through this, it was intended to help with research and policies to create a barrier free environment. The analysis data is 227 papers published in domestic academic journals from 1996 when barrier free research began to 2022. The researcher converted the title, keywords, and abstract of an academic thesis into text, and then analyzed the pattern of the thesis and the meaning of the data. The summary of the research results is as follows. First, barrier-free research began to increase after 2009, with an annual average of 17.1 papers being published. This is related to the implementation guidelines for the barrier-free certification system that took effect on July 15, 2008. Second, results of barrier-free text mining i) As a result of word frequency analysis of top keywords, important keywords such as barrier free, disabled, design, universal design, access, elderly, certification, improvement, evaluation, and space, facility, and environment were searched. ii) As a result of TD-IDF analysis, the main keywords were universal design, design, certification, house, access, elderly, installation, disabled, park, evaluation, architecture, and space. iii) As a result of N-Ggam analysis, barrier free+certification, barrier free+design, barrier free+barrier free, elderly+disabled, disabled+elderly, disabled+convenience facilities, the disabled+the elderly, society+the elderly, convenience facilities+installation, certification+evaluation index, physical+environment, life+quality, etc. appeared in a related language. Third, as a result of the CONCOR analysis, cluster 1 was barrier-free issues and challenges, cluster 2 was universal design and space utilization, cluster 3 was Improving Accessibility for the Disabled, and cluster 4 was barrier free certification and evaluation. Based on the analysis results, this study presented policy implications for vitalizing barrier-free research and establishing a desirable barrier free environment.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.1
• /
• pp.59-67
• /
• 2009

In this paper, we have proposed the structure of the IMADF(improved modified multiplication-free adaptive filter) to cancel the adaptive noise in biomedical signals. The IMADF structure use the one-step predicted filter in the multiplication-free adaptive digital filter(MADF) structure using the DPCM and Sign algorithm. And then we use the heart phantom model based on the magnetocardiographic (MCG) to test the biomedical signals and analyze the signal of it. Their functions of the heart phantom occur from the multidipole current source. This can play role the same in the real function of the human heart to study it. In the experimental results, the IMADF algorithm has reduced the computational complexity by use of only the addition operation without a multiplier. Also, under the condition of identical stationary-state error, it could obtain the stabled convergence characteristics that the IMADF algorithm is almost same as the sign algorithm, but is better than the MADF algorithm. Here, this algorithm has effective characteristics when the correlation of the input signal is highly.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.11 no.5
• /
• pp.89-100
• /
• 2001

The Ritz method Is applied In a three-dimensional (3-D) analysis to obtain accurate frequencies for thick. linearly tapered. annular plates. The method is formulated for annular plates haying any combination of free or fixed boundaries at both Inner and outer edges. Admissible functions for the three displacement components are chosen as trigonometric functions in the circumferential co-ordinate. and a1gebraic polynomials in the radial and thickness co-ordinates. Upper bound convergence of the non-dimensional frequencies to the exact values within at least four significant figures is demonstrated. Comparisons of results for annular plates with linearly varying thickness are made with ones obtained by others using 2-D classical thin place theory. Extensive and accurate ( four significant figures ) frequencies are presented 7or completely free. thick, linearly tapered annular plates haying ratios of average place thickness to difference between outer radius (a) and inner radius (b) radios (h$_{m}$/L) of 0.1 and 0.2 for b/L=0.2 and 0.5. All 3-D modes are included in the analyses : e.g., flexural, thickness-shear. In-plane stretching, and torsional. Because frequency data liven is exact 7o a\ulcorner least four digits. It is benchmark data against which the results from other methods (e.g.. 2-D 7hick plate theory, finite element methods. finite difference methods) and may be compared. Throughout this work, Poisson\`s ratio $\upsilon$ is fixed at 0.3 for numerical calculations.s.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.39C no.5
• /
• pp.447-455
• /
• 2014

In this paper, we consider a representative integral imaging method in glasses-free 3D image processing and propose a prioritized transmission scheme for guaranteeing a received video quality in error-prone environments. According to the correlation of pixels consisting of each voxel of integral image, we set the priority differently and apply the modulation level according to this priority value. That is to say, the corresponding pixels with small variance are set to a high priority and transmitted by using a low level modulation that is robust under transmission errors, but the corresponding pixels with greater variance are set to a lower priority and transmitted by using a high level modulation that has a high bit error rate but fast transmission rate. Result shows that the proposed scheme that applies the error-robust modulation level to the important image bit stream with the high priority improves the peak to sidelobe ratio (PSR) of the received 3D image, compared with a typical method that use the same modulation level without distinction of priorities.