• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.543-548
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• 2017

This paper examines the effects of strong corporate governance for listed companies in accessing capital markets from the point of view of the weighted average cost of capital. Results found that corporate governance had a significant negative(-) relation to the weighted average cost of capital. This finding is consistent with previous research and implies that the higher shareholder ownership and foreign ownership have confidence in the financial information of the company, and therefore, risk is reduced for investors. This results in lower expected rates of return and companies will pay a lower cost of capital. Second, tax evasion had a positive effect(+) on the weighted average cost of capital. The low quality of corporate accounting information is expected to increase tax avoidance. Accordingly, this results in increased risk. If the required rate of return is high in its impact,it leads to increased capital costs. In addition, corporate governance and tax avoidance factors showed a negative affect (-) on the weighted average cost of capital. Corporate governance plays an important role in tax avoidance and the weighted average cost of capital, and strong corporate governance reducesthe impact on tax avoidance. In addition, the weighted average cost of capital in capital markets showed the reducing effect.

• Geophysics and Geophysical Exploration
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• v.23 no.3
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• pp.117-130
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• 2020

Noises can distort acquired geophysical data, leading to their misinterpretation. Potential noises sources include anthropogenic activity, natural phenomena, and instrument noises. Conventional denoising methods such as wavelet transform and filtering techniques, are based on subjective human investigation, which is computationally inefficient and time-consuming. Recently, many researchers attempted to implement neural networks to efficiently remove noise from geophysical data. This study aims to review and analyze different types of neural networks, such as artificial neural networks, convolutional neural networks, autoencoders, residual networks, and wavelet neural networks, which are implemented to remove different types of noises including seismic, transient electromagnetic, ground-penetrating radar, and magnetotelluric surveys. The review analyzes and summarizes the key challenges in the removal of noise from geophysical data using neural network, while proposes and explains solutions to the challenges. The analysis support that the advancement in neural networks can be powerful denoising tools for geophysical data.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.276-284
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• 1993

The ABB-CE System-80 reactor power cutback system(RPCS) is designed to enable continuous operation of the reactor without trip in the events of the loss of one of the two main feedwater pumps and loss of load, and thus improves plant availability in a cost effective manner. In this study expansion of RPCS has been investigated for continuous reactor operation without trip in the event of an inward control element assembly(CEA) deviation including a single rod drop. Under the expanded function of RPCS the control system will provide a rapid core power reduction on demand by releasing CEAs to drop into the core and reduce the turbine power, if necessary, to follow the reactor power variation. This design feature which is included as the new design features to be incorporated in the ABB-CE System-80+ meets the EPRI advanced light water reactor(ALWR) requirements. For this study core analysis models of System-80+ have been developed to simulate the nuclear steam supply system(NSSS) response as well as the RPCS initiation of rapid CEA insertion. The results of this study demonstrate that the reactor trip can be avoided in the event of inward CEA deviation including a single rod drop by the RPCS initiation and thus the plant availability and capacity factor would be increased.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.255-261
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• 2007

Soil aggregates, resulting from physico-chemical and biological interactions, are important to understand carbon dynamics and material transport in soils. The objective of this study is to investigate stable macro-aggregate (> 0.25mm diameter) in wet sieving (SM) and their relation to soil properties in 15 sites. The clay contents of soils were ranged from 1% to 33%, and their land uses included bare and cultivated lands of annual upland crops, orchard, and grass. Undisturbed 3 inch cores with five replicates were sampled at topsoil (i.e., 0- to 10-cm depth), for analyzing SM and physico-chemical properties, after in situ measurement of air permeability. SM of sandy soils, with clay content less than 2%, was observed as 0%. Except the sandy soils, SM of soils mainly depended on land uses, showing 27%~35% in soils with annual plants such as vegetable and corn, 51% in orchard, and 75% in grass. This sequence of SM is probably due to the different strength of soil disturbance like tillage with different land uses. SM had significant correlation with cation exchange capacity, organic matter content, sand, clay, silt, bulk density, and exchangeable potassium (K) and magnesium (Mg), whereas fluctuating properties with fertilization such as pH, EC, and water soluble phosphorus weren't significantly correlated to the SM. Particularly, exchangeable calcium (Ca) had significant relation with SM, only except soils with oversaturating Ca. This study, therefore, suggested that SM could perceive different land uses and the change of soil properties in soils, necessarily considering soil textures and Ca over-saturation.

• Food Science and Preservation
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• v.16 no.3
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• pp.435-441
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• 2009

Activity-guided isolation from the ethylacetate (EtOAc)-soluble portion of a methanolic extract of the seeds of Eriobotrya japonica, using several bioassays, led to the isolation and identification of six phenolic compounds of previously known structure: benzaldehyde (1), chlorogenic acid (2), caffeic acid (3), benzoic acid (4), ferulic acid (5), and amygdalin (6). Of these, benzaldehyde (1) exhibited tyrosinase inhibitory activity in a bioassay. In addition, chlorogenic acid (2) and caffeic acid (3) were found to have strong antioxidative effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and superoxide dismutase (SOD)-like activity.

• Journal of Cadastre & Land InformatiX
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• v.47 no.1
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• pp.111-126
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• 2017

Small-scale UAS(Fusion technique of Unmanned Aerial Vehicles platform and Sensors, 'sUAS') opens various new applications in construction fields and so becoming progressively common due to the considerable potentials in terms of accuracy, costs and abilities. The purpose of this study is that the investigation of the validation on the utilization of sUAS for earth stockpile volume calculations on sites. For this, generate 3D models(DSM) with sUAS aerial images on an cone shaped soil stockpile approximately $270m{\times}300m{\times}20m$, which located at Baegot Life Park in Siheung-si, compared stockpile volume estimates produced by sUAS image analysis, against volume estimates obtained by GNSS Network-RTK ground surveying method which selected as the criteria of earth stockpile volume. The result through comparison and examination show(demonstrate) that there was under 2% difference between the volume calculated with the GNSS Network RTK data and the sUAV data, especially sUAS imaged-based volume estimate of a stockpile can be greatly simplified, done quickly, and very cost effective over conventional terrestrial survey methods. Therefore, with consideration of various plan to assess the height of vegetation, sUAS image-based application expected very useful both volume estimate and 3D geospatial information extraction in small and medium-sized sites.

• Korean Journal of Environment and Ecology
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• v.23 no.2
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• pp.194-207
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• 2009

The study is to suggest a management method for improvement of natural and cultural landscape of Hwayang valley which is degraded in Songnisan National Park. It was carried out to study original shape of landscape of it and analyse nine major properties of Hoayang Gugok, based on old literatures. The landscape of Gugok was composed of rocks and small ponds, Pinus densiflora community and most of them were degraded by the situation of covered rocks by growth of vegetation, destructed small ponds by sedimented sands and degradation of natural landscape by artificial forest. Vegetation landscape of artificial forest composed of Populus tomentiglandulosa, Robinia pseudo-acacia, Pinus koraiensis in periphery of the valley was not matched with natural landscape. The goal of landscape management was established to conserve natural and cultural landscape in Joseon Dynasty. For this, It was needed to protect landscape values of gugok through the management of vegetation and visitors. In addition, it was required to provide opportunity to easily access to the landscape of Gugok. As a management method of vegetation, it was suggested to maintain P. densiflora community and to restore artificial forest to natural forest through the density management.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.9-22
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• 2005

The allowed operation space for the mass damper in an active tuned mass damper (ATMD) system is limited for most civil structures. In this study, a restrained stroke active tuned mass damper (RS-ATMD) system with a end-spring and a holder that reduces the stroke of the mass damper with maintaining the control effect durably is proposed. This new control system functions as a conventional ATMD within the predetermined stroke limitation under small excitation and as an RS-ATMD beyond that limitation under large excitation. A new control algorithm considering such an operation principle of the RS-ATMD are also provided. Parameteric study for the various design factors of the RS-ATMD is conducted and the control effectiveness are investigated in comparison with the ATMD. Exposed to sinusoidal or impact load, the RS-ATMD system shows the considerable reduction of the maximum stroke of the mass damper with the slight diminution in the control effectiveness. Excited by random load, it also shows the considerable reduction of the maximum stroke of the mass damper not allowing the diminution in the control effectiveness.

• Korean Journal of Agricultural Science
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• v.32 no.2
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• pp.233-241
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• 2005

The objective of this study was to investigate the effect of odor removal such as $NH_3$, volatile organic acid (VOA) during the pig manure composting using of the Pyroligneous acid liquor (PAL). The odor removal efficiencies were evaluated throughout the dilution rates (${\times}0$, ${\times}100$, ${\times}300$) of PAL. The results of the study are as followings. $NH_3$ content in all treatments (volume 10L) was approximately 8 mg/kg in compost piles on the first day. In the case of control treatment, it was increased by 46 mg/kg within 10 days and was not detected after 25 days. In contrast, those levels in PA-100 and PA-300 treatments were similar values at 38 mg/kg within 6 days and decreased after 15 days. And GC. equipment was used to analyze the volatile organic acids (acetic acid, butyric acid, isobutyric acid, isovaleric aicd, 2,3-methylbutyric aicd, and propionic acid). The concentration of acetic acid and butyric acid were the higher than other VOAs during the initial composting day and sharply declined after 15 days. The VOAs in the control treatment were detected until 40 days, but PA-100 and PA-300 treatments were not measured after 15 days. The PA-100 in all treatments was the most effective treatment for $NH_3$ gas and VOAs reduction during composting. In addition, these studies for the odor reduction in compost manufacture process would have to research on more effective methods for the PAL utilization in agro-biological aspects.

• Geophysics and Geophysical Exploration
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• v.14 no.4
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• pp.289-297
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• 2011

Chirp sub-bottom profilers (SBP) data are comparatively higher-resolution data than other seismic data and it's raw signal can be used as a final section after conducting basic filtering. However, Chirp SBP signal has possibility to include various noise in high-frequency band and to provide the distorted image for the complex geological structure in time domain. This study aims at the goal to establish the workflow of Chirp SBP data processing for enhanced image and to analyze the proper parameters for the domestic continental shelf. After pre-processing, we include the dynamic S/N filtering to eliminate the high-frequency component noise, the dip scan stack to enhance the continuity of reflection events and finally the post-stack depth migration to correct the distorted structure on the time domain sections. We demonstrated our workflow on the data acquired by domestically widely used equipments and then we could obtain the improved seismic sections of depth domain. This workflow seems to provide the proper seismic section to interpretation when applied to data processing of Chirp SBP that are largely used for domestic acquisition.