• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.55-61
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• 2023

This study aims to develop CLSM fill material for emergency restoration using landfill coal ash. As a result of examining physical properties such as particle size distribution and fines content of landfill coal ash, bottom ash, fly ash, and general soil were mixed, and SP was found to have a density of 2.03 and a residual particle pass rate of 7.8 %. CLSM materials that secure fluidity in unit quantities without using chemical admixtures such as glidants and water reducing agents have a high risk of material separation due to bleeding. As a result of this experiment, it was found that the bleeding ratio did not satisfy the standard in the case of the specimen with a large amount of fly ash and a lot of addition of mixing water. As a result of the compressive strength test, the strength development of 0.5 MPa or more for 4 hours was found to be satisfactory for the specimens using hemihydrate gypsum with a unit binder amount of 200 or more, and the remaining gypsum showed poor strength development. Although it is judged that landfill coal ash can be used as a CLSM material, it is necessary to identify and apply the physical and chemical characteristics of coal ash buried in the ash treatment plant of each power generation company.

• Analytical Science and Technology
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• v.20 no.4
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• pp.279-288
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• 2007

We have studied a method for the preparation of $ACF/TiO_2$ composites involving the penetrationof titanium n-butoxide (TNB) solution into activated carbon fiber. It was focused on the characterization of $TiO_2$ formed in prorous carbon was which increased with surface functional groups by hydrochloric acid treatment. The conversion of TNB to $TiO_2$ for the acid treatment effect must be important for the preparationof $ACF/TiO_2$ composites. From the characterization of surface properties, both the BET surface area and the total pore volume decreased as the distribution of $TiO_2$ on the activated carbon fiber surfaces after acid treatments.The changes in XRD pattern showed the typical anatase type on $ACF/TiO_2$ composite for the sample named FT, FT1 and FT2 treated with 0.05, 0.1 and 0.5 M, respectively. However, XRD patern of FT3 treated with 0.5M showed mixed amatase-rutile structure. According to the results of SEM micrographs, the titanium complexe particles were irregularly distributed around carbon. And some large clusters were found when an amount of acid treatment increased. The EDX results of $ACF/TiO_2$ composites showed the presence of C, O and P with strong Ti peaks. Finally, the excellent photocatalytic activity of the $ACF/TiO_2$ composites between relative concentration($c/c_o$) of MB (methylene blue) and UV irradiation time could be attributed to the both effects between photocatalysis of the formation of titania complexes and adsorptivity of the activated carbon fiber.

• Asia Marketing Journal
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• v.16 no.2
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• pp.39-57
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• 2014

There has been recognition of the increasing importance of cooperation as an element of marketing strategy. Such cooperation is confined to four levels based on product development, sales promotion, pricing arrangements, and place (or distribution) mechanisms as the usual marketing 4Ps mixed (Varadarajan 1986). At present, however, little is known about the nature of tie-in promotion as a cooperative sales promotion comparing three other levels. The primary goal of this study is to examine the effect of consumer - tie-in promotion relationship on loyalty. The construct of consumer - tie-in promotion relationship is based on the previous research on consumer-brand relationship. In addition, this study divides the concept of loyalty into host brand loyalty and partner brand loyalty to reflect the characteristics of tie-in promotion including program in order to determine the effect of the consumer - tie-in promotion relationship on loyalty. The results showed that the three dimensions of the consumer - tie-in promotion relationship (i.e., commitment, intimacy, and interdependence) had significantly positive effect on program loyalty. The effect of program loyalty is significantly on both host and partner brand loyalty. This study empirically tested the relationships among consumer - tie-in promotion relationship, program loyalty, host brand loyalty, and partner brand loyalty, and then compared with the difference in the suggested model for the target customers and non-target customers. As a result, for target customers, intimacy and interdependence among dimensions of consumer - tie-in promotion relationship had significantly positive influence on program loyalty. In case of non-target customers, however, commitment and interdependence among dimensions of consumer - tie-in promotion relationship had significantly positive influence on program loyalty. Also, program loyalty had significantly positive impact on host brand loyalty and partner brand loyalty in both target and non-target customers. This study has significance in that it addresses the need to identify research and academic implications by analyzing the consumer - tie-in promotion relationship to determine the relationship between tie-in promotion and loyalty, which has not been clearly described by previous studies. Furthermore, this study builds a foundation for firms and managers actively using tie-in promotion to establish tie-in promotion strategies that can maximize loyalty for both host and partner brands from the consumers' point of view.

• Information Systems Review
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• v.25 no.4
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• pp.27-45
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• 2023

The importance of information security has grown alongside the development of information and communication technology. However, companies struggle to select suitable countermeasures within their limited budgets. Sönmez and Kılıç (2021) proposed a model using AHP and mixed integer programming to determine the optimal investment combination for mitigating information security breaches. However, their model had limitations: 1) a lack of objective measurement for countermeasure efficacy against security threats, 2) unrealistic scenarios where risk reduction surpassed pre-investment levels, and 3) cost duplication when using a single countermeasure for multiple threats. This paper enhances the model by objectively quantifying countermeasure efficacy using the beta probability distribution. It also resolves unrealistic scenarios and the issue of duplicating investments for a single countermeasure. An empirical analysis was conducted on domestic SMEs to determine investment budgets and risk levels. The improved model outperformed Sönmez and Kılıç's (2021) optimization model. By employing the proposed effectiveness measurement approach, difficulty to evaluate countermeasures can be quantified. Utilizing the improved optimization model allows for deriving an optimal investment portfolio for each countermeasure within a fixed budget, considering information security costs, quantities, and effectiveness. This aids in securing the information security budget and effectively addressing information security threats.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.483-494
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• 2023

Measurement of the physical properties of rocks or minerals is an important factor in determining the distribution of the underground medium as well as mineral resource investigations. Resistivity and induced polarization, which are widely used in Korea, are methods for measuring electrical properties, which are representative properties of obtaining subsurface information. In order to precisely analyze the exploration data obtained from various sites, it is important to accurately measure the material properties. Electrical properties of rock is measured using two-electrode or four-electrode method. Compared to the four-electrode method, the two-electrode method is generally used because it is very easy to contact the sample and the electrode, but there is a problem in that the impedance of the electrode and the sample is measured together. In this study, the time-domain the induced polarization effects were measured using the 2-electrode method and the 4-electrode method for artificial samples mixed with graphite and cement having induced polarization characteristics, and the results were compared. Although the 4-electrode method has difficulties in installing potential electrodes, it was confirmed that it is effective in measuring electrical properties because it can reduce the problem caused by the impedance of potential electrodes compared to the 2-electrode method.

• Journal of the Korea Institute of Building Construction
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• v.23 no.6
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• pp.663-671
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• 2023

This research experimentally evaluated the recyclability of four varieties of lignocellulosic fly ash(FA), a by-product from three power plants employing lignocellulosic biomass(Bio-SRF, wood pellets) as a fuel source. Comprehensive analyses were conducted on FA, encompassing both physical parameters (particle shape, size distribution, fineness, and density) and chemical properties(chemical composition and heavy metal content). Mortar test specimens, with FA mixing ratios ranging from 5 to 20%, were produced in compliance with KS L 5405 standards, and their flow and compressive strength were subsequently measured. The test results indicated that the four types of FA exhibited particle sizes approximately between 20~30㎛, densities around 2.3~2.5g/cm³, and a fineness range of 2,600~4,900cm²/g. The FA comprised approximately 50~90% of components such as SiO₂, Al₂O₃, Fe₂O₃, and CaO, displaying characteristics akin to type-II and type-III FA of KS L 5405 standards, albeit with differences in chlorine and SiO₂ content. From the mortar tests, it was observed that the compressive strength of the mortar ranged between 34~47MPa when the pellet combustion FA was mixed in proportions of 5~20%. FA, produced exclusively from the combustion of 100% lignocellulosic fuel, is assessed to possess high recyclability potential as a substitute for conventional admixtures.

• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.591-603
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• 2020

Purpose The purpose of this study was to describe the clinical features and chest computed tomography (CT) findings of coronavirus disease 2019 (COVID-19) pneumonia. Materials and Methods An Institutional Review Board-approved retrospective review was performed for 51 laboratory-confirmed COVID-19 pneumonia patients. Patients were divided into two groups depending on their clinical status: mild and severe. Clinical characteristics and chest CT findings were compared between the two groups. Results Among the 51 patients (22 men, 29 women; mean age, 56.5 ± 16 years; range, 22-88 years), 37 (72.5%) were in the mild group and 14 (27.5%) were in the severe group. The patients in the severe group (68.7 ± 12.5 years) were older than the patients in the mild group (51.8 ± 14.9 years, p < 0.001). Premorbid conditions and decreased lymphocyte counts were more often observed in the severe group than in the mild group (71% vs. 41%, p = 0.049 and 86% vs. 32%, p = 0.001, respectively). On chest CT, most patients exhibited a mixed ground-glass opacification (GGO) with consolidation (76%) or a GGO (22%) pattern. The majority of lesions were predominantly bilateral in the lower lung with a posterior, peripheral distribution. The patients in the severe group had higher severity scores than those in the mild group. Conclusion Patients with laboratory-confirmed COVID-19 pneumonia have typical chest CT findings that provide important information regarding expected disease severity.

• The Journal of the Acoustical Society of Korea
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• v.43 no.2
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• pp.225-233
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• 2024

Active sonar transmits sound waves to detect covertly maneuvering underwater objects and detects the signals reflected back from the target. However, in addition to the target's echo, the active sonar's received signal is mixed with seafloor, sea surface reverberation, biological noise, and other noise, making target recognition difficult. Conventional techniques for detecting signals above a threshold not only cause false detections or miss targets depending on the set threshold, but also have the problem of having to set an appropriate threshold for various underwater environments. To overcome this, research has been conducted on automatic calculation of threshold values through techniques such as Constant False Alarm Rate (CFAR) and application of advanced tracking filters and association techniques, but there are limitations in environments where a significant number of detections occur. As deep learning technology has recently developed, efforts have been made to apply it in the field of underwater target detection, but it is very difficult to acquire active sonar data for discriminator learning, so not only is the data rare, but there are only a very small number of targets and a relatively large number of non-targets. There are difficulties due to the imbalance of data. In this paper, the image of the energy distribution of the detection signal is used, and a classifier is learned in a way that takes into account the imbalance of the data to distinguish between targets and non-targets and added to the existing technique. Through the proposed technique, target misclassification was minimized and non-targets were eliminated, making target recognition easier for active sonar operators. And the effectiveness of the proposed technique was verified through sea experiment data obtained in the East Sea.

• Economic and Environmental Geology
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• v.57 no.4
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• pp.387-396
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• 2024

The geological disposal of high-level radioactive waste (HLW) involves permanently isolating the wastes in stable geological formations deep underground. Mudstone (siltstone and claystone) containing abundant clay minerals is proposed as a host rock for geological disposal of HLW because clay minerals have low permeability and high ion sorption/exchange capacity. Despite the widespread occurrence of sedimentary basins in Korea, there is a lack of evaluation of mudstone as host rocks for geological disposal. In this study, we utilized the JBH-1 borehole (7-754 m) obtained from the Jinju Formation to investigate the distribution trend and mineral compositions of mudstone. Additionally, we conducted comparative analyses with the Opalinus Clay in Switzerland considered as host rock of geological disposal of HLW. Claystone containing more than 40% clay minerals exhibit thick layers primarily in the upper section (7-350 m) of the JBH-1 borehole. While the clay minerals content of claystone does not show significant variation with depth, there are differences in the characteristics of feldspar and carbonate minerals. These mineralogical variations can led change in pore water chemistry and rock mechanical properties. The clay minerals content of claystone in the Jinju Formation is similar to that of the Opalinus Clay. However, there are notable differences in clay minerals composition. While the Opalinus Clay contains smectite-illite mixed-layer minerals, the Jinju Formation are dominated by illite indicating higher burial temperatures. This information will be useful for studying the host rock of HLW geological disposal site in Korea.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.642-650
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• 1996

Apo E polymorphism (e2, e3, e4) was among the first reported genetic polymorphism that explained part of the normal variation in plasma cholesterol concentrations. Both alleles E2 and E4 are significantly more frequent in patients with mixed forms of hyperlipidemia and contribute on the observed differences in CHD risk among different populations. Effects of apo E polymorphism on the distribution of plasma lipid profiles were studied in 105 normolipidemic healthy women. The relative frequencies of common alleles for gene locus of apo E in this study were that E3 allele was 0.848, E4 allels was 0.087, and E2 allele was 0.067. SBP and DBP were slightly more elevated in E2 allele than those in E3 and E4. The pulsation was also significantly (p<0.016) increased by E2 allele with excess body fat % in E2 allele. There were no differences in total-, total HDL-, VLDL+LDL-, VLDL- and LDL cholesterol among the apo E alleles. However, apo E2 allele subject had lower level of total HDL and HDL2 cholesterol (P<0.047) and significantly higher lev디 of HDL3 cholesterol (P<0.05) than those in apo E3 and E4 allele subject. The conclusion is that first, it seems that apo E4-mediated alteration through LDL B/E receptors or E receptors in cholesterol metabolism results in lower plasma TG or remanate particles and in higher levels of VLDL+LDL or LDL. Second, apo E2 allele shows reciprocal effects of E4 on the plasma lipid metabolism, respecitvely. Third, apo E2 allele was more atherogenic than apo E4 because the higher levels of HDL3/HDL2 ratio and atherogenic index[(TC-HDL)/HDL]were criticized.