• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.1-8
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• 2023

Research, such as developing alternative energy in the transportation field, including aviation, is being actively conducted to solve the issue of current climate change. Interest in ammonia fuel as a carbon free energy (CFE) source is increasing due to the ease of liquefaction and transportation and similarity in energy density to that of methanol. However, explosiveness and toxicity of ammonia make it difficult to handle. Therefore, in this study, stable ammonia production was attempted using relatively easy-to-handle urea water solution (UWS). High temperature steam was used to promote the hydrolysis of ammonia. In order to determine the causes for ammonia production below the theoretical equivalent ratio, it was suggested that there were not enough collisions to promote the hydrolysis based on the kinetic theory of gases. The hydrolysis of unreacted isocyanic acid (HNCO) was tested according to the change in water supply. As a result, an increased amount of ammonia produced was confirmed. The increased amount of ammonia produced in a certain section was dependent on the steam temperature and the flow rate of water supplied.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.967-971
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• 2023

Recently, a variety of AI-based platform services are available, and one of them is ChatGPT that processes a large quantity of data in the natural language and generates an answer after self-learning. ChatGPT can perform various tasks including software programming in the IT sector. Particularly, it may help generate a simple program and correct errors using C Language, which is a major programming language. Accordingly, it is expected that ChatGPT is capable of effectively using Verilog HDL, which is a hardware language created in C Language. Verilog HDL synthesis, however, is to generate imperative sentences in a logical circuit form and thus it needs to be verified whether the products are executed properly. In this paper, we aim to select small-scale logical circuits for ease of experimentation and to verify the results of circuits generated by ChatGPT and human-designed circuits. As to experimental environments, Xilinx ISE 14.7 was used for module modeling, and the xc3s1000 FPGA chip was used for module embodiment. Comparative analysis was performed on the use area and processing time of FPGA to compare the performance of ChatGPT products and Verilog HDL products.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.432-438
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• 2011

The purpose of the present thesis is to develop bankruptcy prediction models capable of being applied to the Korean construction industry and to deduce an optimal model through comparative evaluation of final developed models. A study population was selected as general contractors in the Korean construction industry. In order to ease the sample securing and reliability of data, it was limited to general contractors receiving external audit from the government. The study samples are divided into a bankrupt company group and a non-bankrupt company group. The bankruptcy, insolvency, declaration of insolvency, workout and corporate reorganization were used as selection criteria of a bankrupt company. A company that is not included in the selection criteria of the bankrupt company group was selected as a non-bankrupt company. Accordingly, the study sample is composed of a total of 112 samples and is composed of 48 bankrupt companies and 64 non-bankrupt companies. A financial ratio was used as early predictors for development of an estimation model. A total of 90 financial ratios were used and were divided into growth, profitability, productivity and added value. The MDA (Multivariate Discriminant Analysis) model and BLRA (Binary Logistic Regression Analysis) model were used for development of bankruptcy prediction models. The MDA model is an analysis method often used in the past bankruptcy prediction literature, and the BLRA is an analysis method capable of avoiding equal variance assumption. The stepwise (MDA) and forward stepwise method (BLRA) were used for selection of predictor variables in case of model construction. Twenty two variables were finally used in MDA and BLRA models according to timing of bankruptcy. The ROC-Curve Analysis and Classification Analysis were used for analysis of prediction performance of estimation models. The correct classification rate of an individual bankruptcy prediction model is as follows: 1) one year ago before the event of bankruptcy (MDA: 83.04%, BLRA: 93.75%); 2) two years ago before the event of bankruptcy (MDA: 77.68%, BLRA: 78.57%); 3) 3 years ago before the event of bankruptcy (MDA: 84.82%, BLRA: 91.96%). The AUC (Area Under Curve) of an individual bankruptcy prediction model is as follows. : 1) one year ago before the event of bankruptcy (MDA: 0.933, BLRA: 0.978); 2) two years ago before the event of bankruptcy (MDA: 0.852, BLRA: 0.875); 3) 3 years ago before the event of bankruptcy (MDA: 0.938, BLRA: 0.975). As a result of the present research, accuracy of the BLRA model is higher than the MDA model and its prediction performance is improved.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.779-785
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• 2023

In the creation of non-verbal dance performance, stage costumes are an important element of visual expression and serve an expanded role in addition to its fundamental decorativeness, representation of status reflective of the historical setting of the act and functionality for the dance movement. We intends that the purpose of this research is to analyze the expanded role of the costumes in the creative ballet <'That' Girl>, and through this exercise, provide foundational data on and suggest new future directions for stage costume design. <'That' Girl> is composed of two acts, offering condolences and eliciting empathy by conveying the fear experienced by the victims of the time. The second dance act representing freedom and "Haan" requires this expanded application of costume design. The costume design was inspired by the "Statue of Peace" representing comfort women, and completed through three draft designs and material experiments testing the ease of operation of the strings and fabrics installed in the costumes as well as the functionality of the associated ballet movements. In conclusion, expansion of time & space, expansion of form and expansion of symbolic expression were shown in the dance of liberation using strings wrapped around the arms and through the cloth embodying 'Haan' hidden in front of the costume.

• Journal of the Economic Geographical Society of Korea
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• v.26 no.3
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• pp.223-237
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• 2023

The Seoul Onsu Industrial Complex, having been completed over 50 years ago, is an old industrial complex, with deteriorating infrastructure and factory buildings. Despite this, there's a current urban industrial agglomeration centered on the machinery industry in the Seoul Onsu Industrial Complex. This study aims to holistically analyze the physical deterioration of facilities in the aging industrial complex and the characteristics of industrial agglomeration to derive the identity of the Seoul Onsu Industrial Complex. Based on the research findings, the complex is seeing an enhanced urban industrial agglomeration due to the influx of small-scale businesses resulting from concentrated trade networks in the metropolitan area and plot subdivision, permission for noise-producing processes, and the ease of securing highly-skilled technicians. However, this agglomeration coexists with a weakening of the complex's production function, limited innovativeness of resident companies, and non-innovative features resulting from weakened competitiveness in the metropolitan machinery industry. In summary, the identity of the Seoul Onsu Industrial Complex is a 'Non-Innovative Urban Industry Agglomeration', an old industrial complex, witnessing non-innovative agglomeration based on a machinery industry network centered in the metropolitan area.

• Membrane Journal
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• v.34 no.1
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• pp.79-86
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• 2024

The flat sheet membrane, one of the representative forms of polymeric membranes, is widely used from material research in laboratories to commercial membrane production due to its ease of fabrication. Porous polymeric flat sheet membranes used in microfiltration and ultrafiltration are mainly fabricated through phase separation processes, utilizing non-solvent-induced and vapor-induced phase separation methods. However, due to the nature of phase separation processes, variations between samples can easily occur depending on the surrounding environment and the experimenter, making it difficult to ensure reproducibility. Therefore, for scaling up and ensuring reproducibility of developed membrane fabrication technologies, there is a need for a controlled environment continuous large-area production device, such as a roll-to-roll manufacturing system. This research compared the changes in membrane characteristics due to differences in manufacturing environments when scaling up laboratory-scale fabrication technologies to roll-to-roll processes using knife and slot die coaters. By optimizing the continuous manufacturing process factors, uniformity of the membrane was ensured during large-area production.

• Information Systems Review
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• v.24 no.2
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• pp.67-88
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• 2022

This study proposed a research model that can explain the usage intentions of users and non-users by considering the performance aspects of personal mobility and external environmental factors based on the SOR (Stimulus-Organism-Response) model, A survey was conducted targeting domestic users and non-users, and research models and hypotheses were verified through Partial Least Square (PLS) and Artificial Neural Network (ANN). As a result of the analysis, it was confirmed that the users' perceived satisfaction and perceived trust had a positive effect on their intention to use, and that perceived risk and environmental value had a significant relationship with perceived satisfaction and perceived trust. For non-users, it was found that there was a positive correlation between perceived satisfaction and intention to use, and it was verified that perceived risk and environmental value, like users, were significant antecedents of perceived satisfaction and perceived trust. Among the remaining variables, the perceived mobility of users and the perceived ease of use of non-users were respectively presented as important influencing factors on perceived satisfaction.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.263-279
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• 2024

With the increasing trend of Cloud migration, security threats in the Cloud computing environment have also experienced a significant increase. Consequently, the importance of efficient incident investigation through log data analysis is being emphasized. In Cloud environments, the diversity of services and ease of resource creation generate a large volume of log data. Difficulties remain in determining which events to investigate when an incident occurs, and examining all the extensive log data requires considerable time and effort. Therefore, a systematic approach for efficient data investigation is necessary. CloudTrail, the Amazon Web Services(AWS) logging service, collects logs of all API call events occurring in an account. However, CloudTrail lacks insights into which logs to analyze in the event of an incident. This paper proposes an automated analysis framework that integrates Cloud Matrix and event information for efficient incident investigation. The framework enables simultaneous examination of user behavior log events, event frequency, and attack information. We believe the proposed framework contributes to Cloud incident investigations by efficiently identifying critical events based on the ATT&CK Framework.

• The Korean Journal of Nuclear Medicine Technology
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• v.28 no.1
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• pp.49-56
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• 2024

Purpose: When performing nuclear medicine examinations, body wraps or plastic supports are used to support and immobilize the patient's upper extremities to prevent patient safety accidents. However, the existing plastic supports compromised patient and staff safety, including finger entrapment and falls. Moreover, the body wrap provided by manufacturers compromised image quality such as upper extremities cutoff during whole body bone scan. Therefore, a new design of body wrap was developed to improve the issue, and this study aims to evaluate the usability of this medical body wrap. Materials and Methods: To evaluate the usability of the newly designed medical body wrap, a quality assessment of whole body bone scan images and a user satisfaction survey were conducted. Adult patients (male:female=129:152, age: 60.3±12.4 years, BMI: 24.0±4.2) aged 16 years or older who underwent a whole body bone scan during two periods: June to July 2022 (before improvement, n=139) and June to July 2023 (after improvement, n=142) were randomly selected for image quality evaluation. Five radiotechnologists visually evaluated the posterior view of the whole body bone image, including the left and right elbow (2 points), arm (2 points), whether the hand is extended (2 points), whether the hand is included (2 points), and the number of visible fingers (10 points), with a total of 18 points, which were converted to 100 points and analyzed for difference before and after improvement using an independent sample t-test. The user satisfaction questionnaire was evaluated using a 5-point Likert scale among 16 radiotechnologists from three general hospitals who experienced the new body wrap. Results: The image quality assessment was 82.0±13.8 before the improvement and 89.3±10.1 after the improvement, an average of 7.3 points higher, with a statistically significant difference (t=5.02, p<0.01). The user satisfaction survey showed an overall satisfaction rating of 4.1±0.8 for ease of use, 3.8±0.7 for scan preparation time, 3.9±0.7 for patient safety, 3.8±1.2 for scan accuracy, and 4.2±0.7 for recommendation (87.5% questionnaire response rate). Conclusion: The developed body wrap showed higher image quality and user satisfaction compared to the old method. Considering these results, it is deemed that the new body wrap may be more useful than existing methods.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.356-366
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• 2006

The purpose of this study was to investigate the effects of offering similar experiences for hypothesis-generation based on abduction. Two hundred and seventy eight students in Seoul(8th and 10th grades) were requested to propose causal questions and generate hypotheses after observing an unfamiliar situation. Then, after having been presented numerous similar experimental situations to initial situation, the students were asked to regenerate a hypothesis. When the $X^2$ analysis was done to determine differences in hypothesis generation before and after offering the similar experimental situations, a meaningful difference appeared(p<.001). This study proposes that offering similar experimental situations ease hypothesis-generation based on abductive reasoning. Additionally, the second meaningful difference was discovered when the $X^2$ analysis was carried out to find differences in causal question proposal and hypothesis generation among students who had varied cognitive levels(p<.05) Considering the findings of the study, a progressive stage offering similar scenarios may further abductive reasoning while implementing lessons related to hypothesis generation in middle and high school.