• Journal of Industrial Convergence
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• v.21 no.1
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• pp.175-185
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• 2023

Recently, novel viral infections such as COVID-19 have spread and pose a serious public health problem. In particular, these diseases have a fatal effect on the elderly, threatening life and causing serious social and economic losses. Accordingly, applications such as telemedicine, healthcare, and disease prevention using the Internet of Things (IoT) and artificial intelligence (AI) have been introduced in many industries to improve disease detection, monitoring, and quarantine performance. However, since existing technologies are not applied quickly and comprehensively to the sudden emergence of infectious diseases, they have not been able to prevent large-scale infection and the nationwide spread of infectious diseases in society. Therefore, in this paper, we try to predict the spread of infection by collecting various infection information with regional limitations through a virus disease information collector and performing AI analysis and severity matching through an AI broker. Finally, through the Korea Centers for Disease Control and Prevention, danger alerts are issued to the elderly, messages are sent to block the spread, and information on evacuation from infected areas is quickly provided. A realistic elderly support system compares the location information of the elderly with the information of the infected area and provides an intuitive danger area (infected area) avoidance function with an augmented reality-based smartphone application. When the elderly visit an infected area is confirmed, quarantine management services are provided automatically. In the future, the proposed system can be used as a method of preventing a crushing accident due to sudden crowd concentration in advance by identifying the location-based user density.

• Geophysics and Geophysical Exploration
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• v.26 no.1
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• pp.8-17
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• 2023

Various sources, such as wind, waves, ships, and gas leaks from the seafloor, forms bubbles in the ocean. Underwater bubbles cause signal scattering, considerably affecting acoustic measurements. This characteristic of bubbles is used to block underwater noise by attenuating the intensity of the propagated signal. Recently, researchers have been studying the large-scale release of methane gas as bubble plumes from the seabed. Understanding the physical properties and distribution of bubble plumes is crucial for studying the relation between leaked methane gas and climate change. Therefore, a water tank experiment was conducted to estimate the distribution of bubble plumes using seismic imaging techniques and acoustic signals obtained from artificially generated bubbles using a bubble generator. Reverse time migration was applied to image the bubble plumes while the acquired acoustic envelope signal was used to effectively estimate bubble distribution. Imaging results were compared with optical camera images to verify the estimated bubble distribution. The water tank experiment confirmed that the proposed system could successfully image the distribution of bubble plumes using reverse time migration and the envelope signal. The experiment showed that the scattering signal of artificial bubble plumes can be used for seismic imaging.

• Journal of Broadcast Engineering
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• v.28 no.1
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• pp.145-148
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• 2023

Open-loop Octonion space-time block code for 4 transmit antenna system is considered and random phases are applied to 4 transmit antennas for physical layer security. When an illegal hacker estimates the random phases of 1 through 4 transmit antennas with maximum likelihood (ML), this letter analyzes the bit error rate (BER) performances versus signal-to-noise ratio (SNR). And the Octonion code in the literature[1] does not have full orthogonality so, this letter employs the perfect orthogonal Octonion code. When the hacker knows that the random phases are 2-PSK constellations and he should estimate all the 4 random phases, the hacking is impossible until 100dB. When the hacker possibly know that some of the random phases, bit error rate goes down to 10^-3 so, the transmit message could be hacked.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1267-1273
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• 2022

Although the Korea shipbuilding industry has recently been receiving most of the orders for ships in the world, production processes are being disrupted due to a shortage of manpower at the production site. This is because the workers quit the shipyard as both work and wages were reduced due to the long slump in the shipbuilding industry. The main reason for the increase in orders was the large-scale orders for Qatar LNG carriers, and the situation in which the technical specifications required for ships are becoming more complex is also working to an advantage. Because the contract delivery time is of utmost importance for ships, the dock launch plan is the most important management item among the shipyard's major processes. The structure to be built in the dock may be a hull that has left the design work or a finished vessel, and in some cases, it is often at the level of some blocks of the hull. When launching, the hull is affected by the hogging or sagging moment due to the fluid force, and securing the safety of the structural strength of the block connection is of utmost importance. In a normal process, the connecting member launches after welding has been completed, but in actual shipbuilders, quick decision-making is needed on the conditions for securing structural safety to comply with the docking schedule. In this study, a detailed analysis method and applicability using a bending stress evaluation method and finite element analysis modelling were analyzed to rationally judge the above-mentioned problems from an engineering point of view. The main contents mentioned in the thesis can be used as good examples when conducting similar structural strength evaluations in the future.

• Maritime Security
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• v.5 no.1
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• pp.85-112
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• 2022

The maritime blockade has long been used as a means of war in that it serves as a bridge for economic warfare by paralyzing enemy maritime transport, although it is not a decisive battle, and in the Korean War, U.N. forces have achieved significant results in the war with limited maritime blockade through the Clark Line. However, with China emerging as a maritime powers based on its strong naval power, there is a lack of consideration on how to set up a blockade to block maritime activities and how to respond neutral ships or carrying wartime contraband products if war breaks out again on the Korean Peninsula, In addition, since maritime blockade should be used as a sensitive and flexible naval force projection in that it has interests with neutral countries, it should be carefully reviewed in that it can be used only through careful and reasonable judgment considering the principle of ensuring the legality of maritime blockade Therefore, in this study, Reexamine the process of change in the application of the International Law of Blockade, and through this, Derive the basic principle of ensuring the legitimacy of maritime blockade. In addition, by reviewing the application of these basic principles in the waters off the Korean Peninsula at wartime, we presented answers to research questions by reviewing what needs to be done to neutral ships and ships carrying wartime contraband products, and considered the implications for us

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.201-206
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• 2023

In order to improve the spatial resolution of the gamma camera, the size of the hole in the collimator must be reduced, so the sensitivity is reduced. In order to improve the sensitivity, the size of the hole must be increased, and thus the spatial resolution is reduced. In other words, spatial resolution and sensitivity show opposite characteristics. In this study, a gamma camera was designed to improve both spatial resolution and sensitivity. In order to obtain higher sensitivity in gamma cameras with the same spatial resolution, the structure of the scintillator was designed differently from the existing system. A scintillation pixel was used, and a partition wall was placed between the scintillation pixels to prevent incident gamma rays from being transmitted to other scintillation pixels to interact. Geant4 Application for Tomographic Emission (GATE) simulation was performed to evaluate the performance of the designed gamma camera. When the same sensitivity as the block-type scintillator was obtained, the spatial resolution increased by 16.5%, and when the same spatial resolution was obtained, the sensitivity increased by 61.5%. It is considered that the use of the gamma camera designed in this study can improve the sensitivity compared to the existing system while securing excellent spatial resolution.

• Membrane Journal
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• v.33 no.4
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• pp.211-221
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• 2023

This study presents a comprehensive study on the synthesis and characterization of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C flexible electrodes for energy storage applications. The dual-functional PVI-PGMA copolymer exhibited excellent ionic conductivity, with the PVI-PGMA73/LiTFSI200 membrane electrolyte achieving the highest conductivity of 1.0 × 10^-3 S cm^-1. The electrochemical performance of the CxNy-C electrodes was systematically investigated, with C3N2-C demonstrating superior performance, achieving the highest specific capacitance of 958 F g^-1 and lowest charge transfer resistance (R_ct) due to its highly interconnected hybrid structure comprising nanowires and polyhedrons, along with binary Co/Ni oxides, which provided abundant redox-active sites and facilitated ion diffusion. The presence of a graphitic carbon shell further contributed to the enhanced electrochemical stability during charge-discharge cycles. These results highlight the potential of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C electrodes for advanced energy storage devices, such as supercapacitors and lithium-ion batteries, paving the way for further advancements in sustainable and high-performance energy storage technologies.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.427-438
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• 2023

We carried out a geological survey to classify the types of mass movement in Danyang Geopark (where various rock types are distributed) and analyzed the mechanical and hydraulic characteristics of landslide materials using a series of laboratory tests. Debris flows occurred in areas of limestone/marble, shale, and porphyroblastic gneiss, and limestone/marble landslides were distinguished from the others through the presence of karren topography. Soil tests showed that soil derived from weathered gneiss, which has a higher proportion of coarse grains, has a higher friction angle, lower cohesion, and larger hydraulic conductivity than soils from areas of limestone/marble, and shale. Rock failure mass movements occurred in areas of phyllite, sandstone, and conglomerate and were subdivided into plane failure, block-fall, and boulder-fall types in areas of phyllite, sandstone, and conglomerate, respectively. The shear strength of phyllite is much lower than that of the other types of rock, which have similar rock quality. The slake durability index of the conglomerate is similar to that of the other rock types, which have similar degrees of weathering, but differential weathering of the matrix and clasts was clearly observed when comparing the samples before and after the test. This study can help establish appropriate reinforcement and disaster prevention measures, which depend on the type of mass movement expected given the geological characteristics of an area.

• Journal of Practical Agriculture & Fisheries Research
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• v.15 no.1
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• pp.131-140
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• 2013

Offspring of 14 sows were used to evaluate the effect of yogurt substituted for creep feed on growth performance, diarrhea score and blood profiles. The piglets of sows were randomly allocated into 1 of 2 treatments (1 treatment separated piglets of 7 sows). The dietary treatments were as followed: CF, creep feed; YG, yogurt. The creep feed and yogurt diets were given from 3 d after piglets were born to the day of weaning (21 d after piglets were born). The body weight and feed consumption were weighed and recorded at d 0, 7, 14, and 21 after piglets were born for calculating average daily gain (ADG) and average daily feed intake (ADFI). At the weaning day, two piglets were randomly chosen from each pen and bled via jugular venipuncture to obtain blood samples for WBC and IgG measurement. All data were subjected to the GLM procedures of SAS (2002) as a randomized complete block design, with pen as the experimental unit. Differences among dietary treatments were separated by Duncan's multiple range test, and P < 0.05 was considered statistically significant. No significant difference (P > 0.05) were observed in number of born piglets, weaning pigs, survival rate, body weight of piglets at d 0, 7, 14, and 21, ADG and ADFI. At d 21, piglets fed with creep feed had a higher (P < 0.05) IgG compared with piglets fed with yogurt. No significant difference (P > 0.05) was observed in WBC among treatments at d 21. In conclusion, yogurt substituted for creep feed had no adverse effect on growth performance in lactating piglets.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.41-43
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• 2022

In order to prevent and block infectious diseases caused by the recent COVID-19 pandemic, non-contact biometric information acquisition and analysis technology is attracting attention. The invasive and attached biometric information acquisition method accurately has the advantage of measuring biometric information, but has a risk of increasing contagious diseases due to the close contact. To solve these problems, the non-contact method of extracting biometric information such as human fingerprints, faces, iris, veins, voice, and signatures with automated devices is increasing in various industries as data processing speed increases and recognition accuracy increases. However, although the accuracy of the non-contact biometric data acquisition technology is improved, the non-contact method is greatly influenced by the surrounding environment of the object to be measured, which is resulting in distortion of measurement information and poor accuracy. In this paper, we propose a context-based bio-signal modeling technique for the interpretation of personalized information (image, signal, etc.) for bio-information analysis. Context-based biometric information modeling techniques present a model that considers contextual and user information in biometric information measurement in order to improve performance. The proposed model analyzes signal information based on the feature probability distribution through context-based signal analysis that can maximize the predicted value probability.