• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.2
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• pp.295-303
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• 2023

As the cloud computing market grows, a variety of cloud services are now reliably delivered. Administrative agencies and public institutions of South Korea are transferring all their information systems to cloud systems. It is essential to develop security solutions in advance in order to safely operate cloud services, as protecting cloud services from misuse and malicious access by insiders and outsiders over the Internet is challenging. In this paper, we propose a zero trust model for cloud storage services that store sensitive data. We then verify the effectiveness of the proposed model by operating a cloud storage service. Memory, web, and network forensics are also performed to track access and usage of cloud users depending on the adoption of the zero trust model. As a cloud storage service, we use Amazon S3(Simple Storage Service) and deploy zero trust techniques such as access control lists and key management systems. In order to consider the different types of access to S3, furthermore, we generate service requests inside and outside AWS(Amazon Web Services) and then analyze the results of the zero trust techniques depending on the location of the service request.

• Journal of the Korean GEO-environmental Society
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• v.24 no.4
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• pp.5-11
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• 2023

Impulse waves generated by landslides near water bodies can lead to fatal damage to human life and surrounding infrastructure. These impulse waves are generally called landslide-impulsed waves and occur without being limited to a specific area. Recently, localized torrential rains have frequently occurred due to the influence of abnormal weather, both the frequency and scale of landslides occurring in Korea are increasing. Therefore, in this study, the experiments were conducted according to the mass ratio of the landslide models, and among the characteristics of the generated landslide-impulse waves. And the wave amplitude was observed and analyzed. In this study, a total of 75 experiments were conducted by repeating the experiment 5 times for 15 cases with mass ratios of 5 landslide models and 3 types of slope angles. As a result of experiments with different mass ratios of landslide models, if the landslides have the same initial energy, the size of the landslide-impulse waves generated by mixing granular and block forms is higher than the size of the landslide-impulse waves generated by pure granular and block landslides. It is analyzed that the size may be larger.

• Journal of Industrial Convergence
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• v.21 no.1
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• pp.123-135
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• 2023

In liberal SW education, nurturing student with creative problem-solving ability based on SW is considered important. The purpose of this study is to design SW education and to investigate the effects on students' computational thinking and creative problem solving abilities. This study designed classes in accordance with convergent project and the CT-CPS model and 38 undergraduate students have participated this study. The questionnaire survey was given to students and analyzed the effectiveness of class. The results of this study were as follows: Fitst, SW education significantly improved computational thinking and creative problem solving ability. Second, computational thinking improve significantly in high and low initial score group and creative problem solving improve significantly in low initial score group. However, creative problem solving ability did not improve significantly in high initial score group. Third, computational thinking improve significantly in all majors and creative problem solving improve significantly in college of natural science. However, creative problem solving ability did not improve significantly in college of humanities and social science. In examining the effects on students' computational thinking and creative problem-solving abilities and verify differences by pre-test and major, this study provides significance in expanding the understanding about the nature liberal SW education.

• Journal of Korean Clinical Nursing Research
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• v.16 no.2
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• pp.95-105
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• 2010

Purpose: The purpose of this study was to identify the research trend of 341 studies published in Journal of Korean Clinical Nursing Research from 1995 to 2008. Methods: This study was conducted from May to November, 2009. The tool for analysis developed through literature reviews and discussions of researchers consisted of 7 categories such as characteristics of researchers, research designs, subjects, data collection methods, ethical consideration, nursing interventions, and dependent variables. Data were analyzed by frequency and percentage. Results: The mean number of author per study was 4.7, and clinical nurses were the most frequent as the first author (79.7%) and as a corresponding author (67.1%). Quantitative study was 97.6% and nonexperimental study was 51.7%. The most frequently used research designs were quasi-experimental study (73.9%) among experimental studies and survey study (79.1%) among nonexperimental studies. Patients were the most frequent subjects for studies (55.8%). 46.1% of studies gathered data with questionnaire, 57.7% of studies had consent from patients, and 44.3% of studies used nursing skills for nursing interventions, and 60.0% of studies used clinical end points for dependent variables. Conclusion: The research trend of clinical nursing studies shows that clinical nurses mostly perform quasi-experimental researches to solve patients' problem and frequently use nursing skills for nursing intervention and explore the effect of nursing interventions on clinical end points.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.123-131
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• 2006

Liquefaction-induced lateral spreading has been the most extensive damage to pile foundations during earthquakes. Several cases of pile failures were reported despite the fact that a large margin of safety factor was employed in their design. In this study, 1-g shaking table tests were performed in order to analyze the failure behavior of piles embedded in liquefied soil deposits by buckling instability. As a result, it can be concluded that the pile subjected to excessive axial loads $(near\;P_{cr})$ can fail easily by buckling instability during liquefaction. When lateral spreading took place in sloping grounds, it was found that lateral loading due to lateral spreading increased lateral deflection of pile and reduced the buckling load. In addition, from the buckling shape of pile, difference between Euler's buckling and pile buckling vat observed. In the case of pile buckling, hinge formed at the middle point of the pile, not at the bottom. And in sloping grounds, location of hinge formation got lower compared with level ground because of the soil movements.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.25-40
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• 2007

Excessive earth pressure is one of the major mechanical factors in the deformation and damage of Cut-and-Cover Tunnel lining in shallow tunnels and portals of mountain tunnels (Kim, 2000). Excessive earth pressure may be attributed to insufficient compaction and consolidation of backfill material due to self-weight, precipitation and vibration caused by traffic (Komiya et al., 2000; Taylor et al., 1984; Yoo, 1997). Even though there were a lot of tests performed to determine the earth pressure acting on the tunnel lining, unfortunately there were almost no case histories of studies performed to determine remedial measures that reduce differential settlement and excessive earth pressure. In this study the installation of geotextile mat was selected to reduce the differential settlement and excessive earth pressure acting on the cut-and-cover tunnel lining. In order to determine settlement and earth pressure reduction effect (reinforcement effect) of geotextile mat reinforcement, laboratory tunnel model tests were performed. This study was limited to the modeling of rigid circular cut-and-cover tunnel constructed at a depth of $1.0D\sim1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. Model tests with varying soil cover, mat reinforcement scheme and slope roughness were performed to determine the most effective mat reinforcement scheme. Slope roughness was adjusted by attaching sandpaper #100, #400 and acetate on the cut slope surface. Mat reinforcement effect of each mat reinforcement scheme were presented by the comparison of earth pressure obtained from the unreinforced and mat reinforced model tests. Soil settlement reduction was analyzed and presented using the Picture Analysis Method (Park, 2003).

• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.15-26
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• 2006

Although numerous investigations have been performed over the years to predict the behavior and bearing capacity of piles, the mechanisms are not yet entirely understood. The prediction of bearing capacity is a difficult task, because large numbers of factors affect the capacity and also have complex relationship one another. Therefore, it is extremely difficult to search the essential factors among many factors, which are related with ground condition, pile type, driving condition and others, and then appropriately consider complicated relationship among the searched factors. The present paper describes the application of Artificial Neural Network (ANN) in predicting the capacity including its components at the tip and along the shaft from dynamic load test of the driven piles. Firstly, the effect of each factor on the value of bearing capacity is investigated on the basis of sensitivity analysis using ANN modeling. Secondly, the authors use the design methodology composed of ANN and genetic algorithm (GA) to find optimal neural network model to predict the bearing capacity. The authors allow this methodology to find the appropriate combination of input parameters, the number of hidden units and the transfer structure among the input, the hidden and the out layers. The results of this study indicate that the neural network model serves as a reliable and simple predictive tool for the bearing capacity of driven piles.

• Journal of the Korean Geotechnical Society
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• v.25 no.8
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• pp.33-45
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• 2009

The conventional single-core PBDs have been widely used in order to accelerate consolidation settlement of soft grounds. When using the single-core PBD in a thick clay deposit, a delay of consolidation may occur due to high confining pressure in the thick deposit and necking of drains. This study is to compare the performances of soil improvement by the single-core and double-core PBD installed at a site in Busan New Port which exhibits approximately a 40m-thick clay layer. An in-situ test program was performed at the test site where a set of the double-core PBDs and single-core PBDs were installed to compare the efficiency of each drain. In addition, the discharge capacity of each PBD has been measured using the modified Delft Test. A series of laboratory tests for estimating in-situ soil properties have also been performed in order to obtain input parameters for a numerical program ILLICON. The discharge capacity of the double-core PBD is higher than that of the single-core PBD in the modified Delft Test. However it is observed from the comparative in-situ test and numerical analysis that there is no difference in the performance of ground improvement between the two drain systems. This discrepancy comes from the fact that the amount of water released during consolidation in most common field conditions is much smaller than the capacity of even the single core PBD. And thus, considering actual field conditions, it can be concluded that the single-core PBD has enough discharge capacity even in the thick clay deposit such as this test site.

• Journal of the Korean Geotechnical Society
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• v.26 no.2
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• pp.23-32
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• 2010

This study was especially conducted to find out the characteristics of the lightweight air-mixed soil (slurry density 10 kN/$m^3$) containing silt related to water. Compression strength, permeability, and capillary height of the lightweight air-mixed soil were studied, and also to support these studies, the structure of that soil was analyzed in detail. Air bubbles of various sizes are inside the lightweight air-mixed soil, and its distribution in a location is almost constant. A numerous tiny pores are inside the air bubbles so that the lightweight air-mixed soil can be saturated with water. Porosity is also estimated through the image analysis. Peak strength of the lightweight air-mixed soil is not dependent on water, but behavior of stress-strain is affected by the water. Permeability is about $4.857{\times}10^{-6}cm/sec$, which is a little bit higher than the clay's permeability. Capillary rise occurs rapidly at the beginning of the test until the lapse of 100 minutes and then its increase rate becomes slow. The capillary rise causes the increase of the density of the lightweight air-mixed soil, and thus it is required to pay attention to this phenomenon during structure design and maintenance of the lightweight air-mixed soil.

• Animal Bioscience
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• v.36 no.6
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• pp.929-942
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• 2023

Objective: This study was conducted to evaluate the effects of β-glucan with vitamin E supplementation on the growth performance, blood profiles, immune response, pork quality, pork flavor, and economic benefit in growing and finishing pigs. Methods: A total of 140 growing pigs ([Yorkshire×Landrace]×Duroc) were assigned to five treatments considering sex and initial body weight (BW) in 4 replications with 7 pigs per pen in a randomized complete block design. The experimental diets included a corn-soybean meal-based basal diet with or without 0.05% or 0.1% β-glucan and 0.02% vitamin E. The pigs were fed the diets for 12 weeks (phase I, 0 to 3; phase II, 3 to 6; phase III, 6 to 9; phase IV, 9 to 12). The BW and feed intake were measured at the end of each phase. Blood samples were collected at the end of each phase. Four pigs from each treatment were selected and slaughtered for meat quality. Economic benefit was calculated considering the total feed intake and feed price. Pork flavor was analyzed through inosine monophosphate analysis. Results: The average daily gain and feed efficiency were improved compared to the control when β-glucan or vitamin E was added. Supplementing 0.05% β-glucan significantly increased the lymphocyte concentration compared to the addition of 0.1% β-glucan and the content of vitamin E in the blood increased when 0.02% vitamin E was added. The treatment with 0.1% β-glucan and 0.02% vitamin E showed the most economic effect because it had the shortest days to market weight and the lowest total feed cost. The addition of β-glucan or vitamin E had a positive role in improving the flavor of pork when considering that the content of inosine monophosphate was increased. However, carcass traits and meat quality were not affected by β-glucan or vitamin E. Conclusion: The addition of 0.1% β-glucan with 0.02% vitamin E in growing and finishing pig diets showed great growth performance and economic effects by supplying vitamin E efficiently and by improving the health condition of pigs due to β-glucan.