• Journal of Climate Change Research
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• v.6 no.4
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• pp.311-318
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• 2015

Emission characteristics from charbroiling of four different meats (beef, port, duck and chicken) in a pilot-scale cooking facility were investigated in this study. The analyzed air pollutants include gaseous species (CO, NO, $SO_2$, $NH_3$ and PAHs) as well as particulate matters (TSP, $PM_{10}$, $PM_{2.5}$ and black carbon). The emission factors of $PM_{10}$ and PAHs were in the range of 3~47 g-PM/kg-meat and 0.6~11.41 mg-PAHs/kg-meat, respectively, depending on the type of a meat. In addition, the results also revealed that the high ratio of $PM_{2.5}$ to TSP in a meat charbroiling should be considered to design and to operate air pollution control devices.

• Journal of IKEEE
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• v.23 no.3
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• pp.954-961
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• 2019

This paper suggests an advanced 8T SRAM which can operate properly in subthreshold voltage regime. The memory cell consists of symmetric 8 transistors, in which the latch storing data is controlled by a column-wise assistline. During the read, the data storage nodes are temporarily decoupled from the read path, thus eliminating the read disturbance. Additionally, the cell keeps the noise-vulnerable 'low' node close to the ground, thereby improving the dummy-read stability. In the write, the boosted wordline facilitates to change the contents of the memory bit. At 0.4 V supply, the advanced 8T cell achieves 65% higher dummy-read stability and 3.7 times better write-ability compared to the commercialized 8T cell. The proposed cell and circuit techniques have been verified in a 16-kbit SRAM array designed with an industrial 180-nm low-power CMOS process.

• Computers and Concrete
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• v.27 no.4
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• pp.333-341
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• 2021

Steel slag, an industrial reject from the steel rolling process, has been identified as one of the suitable, environmentally friendly materials for concrete production. Given that the coarse aggregate portion represents about 70% of concrete constituents, other economic approaches have been found in the use of alternative materials such as steel slag in concrete. Unfortunately, a standard framework for its application is still lacking. Therefore, this study proposed functional model equations for the determination of strength properties (compression and splitting tensile) of steel slag aggregate concrete (SSAC), using gene expression programming (GEP). The study, in the experimental phase, utilized steel slag as a partial replacement of crushed rock, in steps 20%, 40%, 60%, 80%, and 100%, respectively. The predictor variables included in the analysis were cement, sand, granite, steel slag, water/cement ratio, and curing regime (age). For the model development, 60-75% of the dataset was used as the training set, while the remaining data was used for testing the model. Empirical results illustrate that steel aggregate could be used up to 100% replacement of conventional aggregate, while also yielding comparable results as the latter. The GEP-based functional relations were tested statistically. The minimum absolute percentage error (MAPE), and root mean square error (RMSE) for compressive strength are 6.9 and 1.4, and 12.52 and 0.91 for the train and test datasets, respectively. With the consistency of both the training and testing datasets, the model has shown a strong capacity to predict the strength properties of SSAC. The results showed that the proposed model equations are reliably suitable for estimating SSAC strength properties. The GEP-based formula is relatively simple and useful for pre-design applications.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.975-980
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• 2021

As technology utilizing low-power short-range wireless communication is applied in conjunction with medical information as a development of the fourth industrial revolution, interest in medical information is increasing. As the age group of smart devices increases and becomes more common, related research such as linking mobile devices with various objects and equipment is continuously being conducted. In addition, interest in untact (non-face-to-face) is increasing due to the prevalence of Coronavirus Disease-19 (COVID-19), including various infectious diseases. As a result, it is a state that requires distance not only in social but also in life. In this study, using a low-power near-field wireless communication technology of beacons to create an IoT device by communicating with the web server of the medical information system was studied to make it easier to receive medical treatment during visits to medical institutions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.7
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• pp.1047-1059
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• 2022

With the development of cloud computing technology, container technology that provides services based on a virtual environment is also developing. Container orchestration technology is a key element for cloud services, and it has become an important core technology for building, deploying, and testing large-scale containers with automation. Originally designed by Google and now managed by the Linux Foundation, Kubernetes is one of the container orchestrations and has become the de facto standard. However, despite the increasing use of Kubernetes in container orchestration, the number of incidents due to security vulnerabilities is also increasing. Therefore, in this paper, we study the vulnerabilities of Kubernetes and propose a security policy that can consider security from the initial development or design stage through threat analysis. In particular, we intend to present a specific security guide by classifying security threats by applying STRIDE threat modeling.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1642-1648
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• 2021

We analyzes representative technologies of IoT patents and reflects these results in the curriculum of IoT. In order to identify the representative technologies, the IPC codes of the patents were analyzed. Among the main category IPC codes, the most used IPC codes were H04L in Single IPC Patent with 974 cases(32.0%) and G06Q in Multiple IPC Patent with 710 cases(29.2%). As a result of classifying the IPC code into the WIPO technology classification system, the most emphasized technologies are Digital Communication, accounting for about 60.5% in the Single IPC Patent and IT Methods for Management(710 cases, 29.2%) in Multiple IPC Patent. The main points to be considered when organizing the curriculum of IoT are: ∇Emphasis on Digital Communication, ∇Expansion of Education related to IT Methods for Management(Including entrepreneurship and patent application), and ∇Consideration of subjects related to the Convergence of IoT. This research can contribute to the curriculum design of new industrial technologies such as AI and Fintech.

• 한국정보교육학회:학술대회논문집
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• 2021.08a
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• pp.213-221
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• 2021

With the advent of the 4th industrial revolution, the need for artificial intelligence education has increased. The online learning environment caused by COVID-19 made it possible to use variety of artificial intelligence platforms. In this study, an aritificial intelligence class plan was developed and proposed to achieve the goal of artificial intelligence education using an AI platform. The AI platform used is AI for Oceans, With the theme of creating a program for the environment, designed a 6-hour project class using Novel Engineering-based on STEAM model. Students experience AI for Oceans enough time and learn supervised learning by experience. Based on understanding of supervised learning, students design their own programs for the environment using Entry's AI blocks. In this study, for AI convergence education, this lesson was developed and presented with the goal of acquiring the creative problem solving ability and integrated thinking ability by using the principles of artificial intelligence to solve problems.

• Journal of Practical Engineering Education
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• v.15 no.3
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• pp.571-580
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• 2023

With the advent of the Fourth Industrial Revolution, there is an increasing demand for interdisciplinary studies in the realm of university education. Accordingly, this study sought to explore learners' perceived expectation factors for a modular curriculum, one of the primary strategies for curriculum revision in interdisciplinary departments, by applying the Expectation Theory. Learners' perceptions were measured pre and post during the second semester of 2022. The results confirmed that among the expectation factors, the selection factor significantly decreased after the course compared to before. Changes in the understanding and perceived difficulty level of tool utilization within the course may have influenced these results. The significance of this study lies in providing direction for curriculum revisions in interdisciplinary departments by analyzing learners' perceptions of the modular curriculum. Specifically, curriculum design should focus on reducing difficulties and cognitive burdens associated with educational tool utilization. Furthermore, considering that students' prior experience and understanding of educational tools can impact educational outcomes, it is crucial to factor these elements when designing a modular curriculum.

• Journal of the Korean Institute of Gas
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• v.28 no.2
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• pp.7-16
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• 2024

This study presents investigation on the technical characteristics and field cases of the salt cavern storage method for large-scale hydrogen storage. The salt cavern storage method enables effective hydrogen storage compared to other methods due to the low porosity and permeability of the rock salt that constitutes the cavern, which is not likely to leak and requires a small amount of cushion gas for operation. In addition, there is no chemical reaction between rock salt and hydrogen, and multiple injection/withdrawl cycles can be performed making it effective for peak shaving and short-term storage. The salt cavern is formed in three stages: leaching, debrining, and filling, and leakage tests are conducted to ensure stable operation. Field applications are currently performing to meet industrial demand in the surrounding area of four sites in the UK and Texas, USA, and salt cavern operation is being prepared for energy storage in European countries such as Germany and France. The investigated results in this study can be utilized as a basic guideline for the design of future hydrogen storage projects.

• Journal of Technologic Dentistry
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• v.46 no.3
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• pp.73-83
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• 2024

Purpose: This study aimed to investigate whether the accuracy and internal porosity of removable partial denture frameworks differ depending on the build direction in the selective laser melting method. Methods: A partially edentulous maxillary study model was scanned, and the anterior-posterior palatal bar was then digitally designed. The angles formed between the z-axis and the path of the insertion and removal were divided into five groups: -60°, -30°, 0°, 30°, and 60°. For each group, three removable partial denture metal frameworks were fabricated and used as specimens. The inner surface of each sample was scanned and superimposed on the design file to obtain the root mean square (RMS) value, and the average RMS value of each group was measured. One sample was randomly selected from each group, and the equivalent diameter and sphericity of the pores were analyzed using industrial X-ray three-dimensional computed tomography. To compare statistical differences between groups, the Kruskal-Wallis test of SPSS Statistics ver. 27.0 (IBM) was used (α=0.05). Results: The average RMS values of the whole inner surface accuracy of the specimens were in the order of -60°<0°<-30°<30°<60° (p<0.05). The equivalent diameter and sphericity of internal pores were significantly different among groups (p<0.001). Conclusion: The build orientation of the selective laser melting method influences the accuracy and internal porosity of removable partial denture frameworks.