• Coupled systems mechanics
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• v.12 no.2
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• pp.167-181
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• 2023

The determination of the blast protection level and the corresponding minimum load-bearing capacity for a laminated glass (LG) window is of crucial importance for safety and security design purposes. In this paper, the focus is given to the window response under near-field blast loading, i.e., where relatively small explosives would be activated close to the target, representative of attack scenarios using small commercial drones. In general, the assessment of the load-bearing capacity of a window is based on complex and expensive experiments, which can be conducted for a small number of configurations. On the other hand, nowadays, validated numerical simulations tools based on the Finite Element Method (FEM) are available to partially substitute the physical tests for the assessment of the performance of various LG systems, especially for the far-field blast loading. However, very little literature is available on the LG window performance under near-field blast loads, which differs from far-field situations in two points: i) the duration of the load is very short, since the blast wavelength tends to increase with the distance and ii) the load distribution is not uniform over the window surface, as opposed to the almost plane wave configuration for far-field configurations. Therefore, the current study focuses on the performance assessment and structural behaviour of LG windows under near-field blasts. Typical behavioural trends are investigated, by taking into account possible relevant damage mechanisms in the LG window components, while size effects for target LG windows are also addressed under a multitude of blast loading configurations.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.498-505
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• 2024

In this paper, a cable-driven endoscopic manipulator (CEM) is designed for the Chinese latest compact fusion reactor. The whole CEM arm is more than 3000 mm long and includes end vision tools, an endoscopic manipulator/control system, a feeding system, a drag chain system, support systems, a neutron shield door, etc. It can cover a range of ±45° of the vacuum chamber by working in a wrap-around mode, etc., to meet the need for observation at any position and angle. By placing all drive motors in the end drive box via a cable drive, cooling, and radiation protection of the entire robot can be facilitated. To address the CEM motion control problem, a discrete trajectory tracking method is proposed. By restricting each joint of the CEM to the target curve through segmental fitting, the trajectory tracking control is completed. To avoid the joint rotation angle overrun, a joint limit rotation angle optimization method is proposed based on the equivalent rod length principle. Finally, the CEM simulation system is established. The rationality of the structure design and the effectiveness of the motion control algorithm are verified by the simulation.

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.437-451
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• 2019

Purpose: The purpose of this study is to improve the quality of the PGM system by improving the structure and production process of slip-ring rotary joint for radar. Methods: The improvement measures for each cause are established through failure analysis of broken items. Specifically, changing in the housing to improve the heating system. Changing the transportation method to prevent damage to equipment during transport. Changing work process of the attenuator ring to prevent damage. etc. Results: The results of this study are as follows; improving the heating system reduces heat generated by the attenuator by about 7 degrees and obtain additional temperature margins. Reduction of defect rate because of adding X-band rotary joint run-out measurement test, ESS of slip-ring rotary joint and Transportation improvement(reinforced flight boxes, tube protection, etc). Getting stable VSWR values by improving work process of attenuator overheating due to a bad bonding process. Conclusion: Through this study, improvements were made to slip-ring rotary joint that failed repeatedly for various reasons. As a result of the application of the improvements, the same fault does not occur until now, so we can see that the quality of PGM has improved.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.53-58
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• 2002

Sheath circulating current is increased as the change of sheath mutual impedance which is caused by imbalance of cable system, and different section length between joint box. If excessive current flows in sheath. sheath loss will be increased and then transmission capacity of underground transmission system is reduced. Accordingly, This paper proposed sheath current reduction device using resistor and reactor and proved the reduction effect of that device using EMTP/ATP. And also in this paper, when transients are occurred at the underground system with reduction device by ground fault and lightning surge. we analyzes transient effect of system variously. From this result. authors establish the protection methods of sheath circulating current reduction device.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1646-1648
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• 1994

In the system of underground transmission line, the rate of electrical failure is very low, but, if once occuring, the failure evolves into a paralysis of the system, the time of restoration is very long, the damage from stopping of power supply is very serious, and the cost of restoration is very great. Because of these problems, you must try to protect the system and equipment from every electrical failure by contributing much carefulness to the design and operation of the underground system. This study summerizes the results of simmulation tests about the effect of installing this protection device on the insulated joint box and the terminal end box.

• Structural Engineering and Mechanics
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• v.32 no.2
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• pp.321-335
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• 2009

When a roof frame is subjected to the airblast loading, the conventional way to analyze the damage of the frame or design the frame is to use single degree of freedom (SDOF) model. Although a roof frame consists of beams and girders, a typical SDOF analysis can be conducted only separately for each component. Thus, the rigid body motion of beams by deflections of supporting girders can not be easily considered. Neglecting the beam-girder interaction in the SDOF analysis may cause serious inaccuracies in the response values in both Pressure-Impulse curve (P-I) and Charge Weight-Standoff Diagrams (CWSD). In this paper, an inelastic two degrees of freedom (TDOF) model is developed, based on force equilibrium equations, to consider beam-girder interaction, and to assess if the modified SDOF analysis can be a reasonable design approach.

• The Journal of the Korea Contents Association
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• v.5 no.1
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• pp.55-63
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• 2005

In undeniable digital signature scheme, the signature can not be verified without the signer's cooperation. The undeniable signature scheme can be used to computerize many applications which can not be done by a conventional digital signature scheme. In this study, we propose the undeniable digital multi-signature scheme which requires many signers and designated verifier The multi-signature can be verified only in cooperation with all signers. The proposed scheme satisfies undeniable property and it is secure against active attacks such as modification and denial of the multi-signature by signers. We also propose copyright protection method of co-authored digital contents as an application of the proposed scheme.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.261-268
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• 2024

This study focused on social connection apps and support among various measures to prevent 'killing and abandonment of infants', which has recently become a social issue. The research method attempted to show the necessity of a social-linked app by analyzing the contents of 12 cases with peculiarities in the infant murder process in the judgment after 2021. Infanticide mothers were found to be economically and socially vulnerable, and they killed infants to continue their lives. Focusing on the mind of human respect rather than the judicial meaning of punishing crime, the development of social connection apps and support services that allow both mothers and infants to be healthy and socially protected were proposed. The first is a great transformation of economic support and awareness for pregnancy, childbirth, and parenting. Second, it is necessary to develop a confidentiality counseling and information app that can comprehensively support medical directions and social welfare in consideration of the health status of the fetus and women and the socio-economic situation. Third, it is proposed to promote the use of the Internet such as joint childcare facilities of social communities, child protection institutions, and adoption systems. The government should investigate the reasons for not being able to register birth, the root causes of killing and abandonment of infants, and come up with practical plans and policies for them.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.3 s.303
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• pp.31-40
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• 2005

In this paper, we develop an approach toward JSC(Joint Source-Channel Coding) method for MPEG-4 based FGS(Fine Granular Scalability) video coding and transmission in fixed and mobile receiving environment(Digital Audio Broadcasting, DAB). The source coder used MPEG-4 FGS video codec, the channel coder used RCPC(Rate Compatible Punctured Convolution) code and the modulation method used QPSK modulation. We have considered channel environment of AWGN and mobile receiving environment. This study determined optimum Trade-off point between source bit rate and channel coding rate in variable channel states. We compared FGS-JSC method and general single layer CBR(Constant Bit Rate) transmission. In this results, FGS-JSC was appeared better performance than CBR transmission.

• The Journal of Korean Medicine
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• v.28 no.4
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• pp.148-157
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• 2007

Background & Objective: Articular cartilage is a potential target for drugs designed to inhibit the activity of matrix metalloproteinases (MMPs) to stop or slow the destruction of the proteoglycanand collagen in the cartilage extracellular matrix. The purpose of this study was to investigate the effects of Cinnamomum cassia in inhibiting the release of glycosaminoglycan (GAG), the degradation of collagen, and MMP activity in rabbit and human articular cartilage explants. Methods: The cartilage-protective effects of Cinnamomum cassia were evaluated by using glycosaminoglycan degradation assay, collagen degradation assay, colorimetric analysis of MMP activity, measurement of lactate dehydrogenase activity and histological analysis in rabbit cartilage explants culture. Results: Interleukin-1a (IL-1a) rapidly induced GAG, but collagen was much less readily released from cartilage explants. Cinnamomum cassia significantly inhibited GAG and collagen release in a concentration-dependent manner. Cinnamomum cassia dose-dependently inhibited MMP-1, MMP-3 and MMP-13 activities from IL-1a-treated cartilage explants culture when tested at concentrations ranging from 0.02 to 1 mg/ml. Conclusion : These results indicate that Cinnamomum cassia inhibits the degradation of proteoglycan and collagen through the down regulation of MMP-1, MMP-3 and MMP-13 activities of IL-1a-stimulated rabbit and human articular cartilage explants.