• Biomolecules & Therapeutics
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• v.29 no.3
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• pp.295-302
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• 2021

Microglial priming is the process of microglial proliferation and activation in response to neurodegeneration and abnormal protein accumulation. Priming makes microglia susceptible to secondary inflammatory stimuli and causes exaggerated inflammatory responses. In the present study, we established a microglial priming model in mice by administering a single injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 20 mg/kg). MPTP induced microglial activation without dopaminergic degeneration; however, subsequent treatment with a sub-toxic dose of lipopolysaccharides (LPS) induced an amplified inflammatory response and caused nigrostriatal dopaminergic degeneration. These pathological and inflammatory changes, including microglial activation and dopaminergic cell loss in the substantia nigra (SN) area were reversed by papaverine (PAP) administration. In addition, MPTP/LPS enhanced interleukin-1β (IL-1β) expression and processing via nod-like receptor protein 3 (NLRP3) inflammasome activation in the SN region of mice. However, PAP treatment suppressed inflammasome activation and subsequent IL-1β maturation. Moreover, PAP inhibited nuclear factor-κB (NF-κB) and enhanced cAMP-response element binding protein (CREB) activity in the SN of MPTP/LPS mice. These results suggest that PAP inhibits the activation of NLRP3 inflammasome by modulating NF-κB and CREB signaling pathways, which results in reduced microglial activation and neuronal cell death. Thus, PAP may be a potential candidate for the treatment of Parkinsons's disease, which is aggravated by systemic inflammation.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.337-345
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• 2023

This study analyzes considerations for satellite orbit elements for the national micro-satellite system to effectively perform its mission in accordance with the operational concept, and compares the conventionally used Walker method to improve the performance of the satellite constellation method of the repeating ground track orbit. In satellite orbit element analysis, altitude candidate values of micro-satellite system, use of eccentricity and argument of perigee through frozen orbit, necessity of selection of appropriate orbit inclination, and satellite phasing rules for flying the same repeating ground track orbit are proposed. Based on these analysis results, the superiority of the constellation method of the repeating ground track orbit compared to the Walker method is verified in terms of revisit performance analysis, global coverage characteristics, and orbit consistency.

• Structural Engineering and Mechanics
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• v.84 no.4
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• pp.489-502
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• 2022

This paper is aimed at developing an optimization-based Finite Element model updating approach for structural damage identification and quantification. A modal flexibility-based error function is introduced, which uses modal assurance criterion to formulate the updating problem as an optimization problem. Because of the inexplicit input/output relationship between the candidate solutions and the error function's output, a robust and efficient optimization algorithm should be employed to evaluate the solution domain and find the global extremum with high speed and accuracy. This paper proposes a new multi-stage Selective Particle Swarm Optimization (SPSO) algorithm to solve the optimization problem. The proposed multi-stage strategy not only fixes the premature convergence of the original Particle Swarm Optimization (PSO) algorithm, but also increases the speed of the search stage and reduces the corresponding computational costs, without changing or adding extra terms to the algorithm's formulation. Solving the introduced objective function with the proposed multi-stage SPSO leads to a smart feedback-wise and self-adjusting damage detection method, which can effectively assess the health of the structural systems. The performance and precision of the proposed method are verified and benchmarked against the original PSO and some of its most popular variants, including SPSO, DPSO, APSO, and MSPSO. For this purpose, two numerical examples of complex civil engineering structures under different damage patterns are studied. Comparative studies are also carried out to evaluate the performance of the proposed method in the presence of measurement errors. Moreover, the robustness and accuracy of the method are validated by assessing the health of a six-story shear-type building structure tested on a shake table. The obtained results introduced the proposed method as an effective and robust damage detection method even if the first few vibration modes are utilized to form the objective function.

• Advances in aircraft and spacecraft science
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• v.10 no.3
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• pp.223-243
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• 2023

There is a burgeoning demand for minimizing the mass of satellites because of its direct impact on reducing launch-to-orbit cost. This must be done without compromising the structure's efficiency. The present paper introduces a relatively low-cost and easily implementable approach for optimizing structural mass to a maximum natural frequency. The natural frequencies of the satellite are of utmost pertinence to the application requirements, as the sensitive electronic instrumentation and onboard computers should not be affected by the vibrations of the satellite structure. This methodology is applied to a realistic model of Al-Azhar University micro-satellite in partnership with the Egyptian Space Agency. The procedure used in structural design can be summarized in two steps. The first step is to select the most favorable primary structural configuration among several different candidate variants. The nominated variant is selected as the one scoring maximum relative dynamic stiffness. The second step is to use perforation patterns reduce the overall mass of structural elements in the selected variant without changing the weight. The results of the presented procedure demonstrate that the mass reduction percentage was found to be 39% when compared to the unperforated configuration that had the same plate thickness. The findings of this study challenge the commonly accepted notion that isogrid perforations are the most effective means of achieving the goal of reducing mass while maintaining stiffness. Rather, the study highlights the potential benefits of exploring a wider range of perforation unit cells during the design process. The study revealed that rectangular perforation patterns had the lowest efficiency in terms of modal stiffness, while triangular patterns resulted in the highest efficiency. These results suggest that there may be significant gains to be made by considering a broader range of perforation shapes and configurations in the design of lightweight structures.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.187-193
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• 2017

This study evaluated tidal stream energy resources according to tidal flow properties around Uido off the west coast of, Jeollanam-do, South Korea. A feasibility study was first carried out through the collection of bathymetry data and tidal phase information. For this simulation, a depth-averaged 2D ADCIRC (Advanced Circulation) model for real sea situations was applied to a Finite Element Method (FEM) approach for tides given the variation of tidal current speed. Hydrodynamics were simulated with 4 major tidal constituents (M2, S2, K1, and O1) after setting up 4 observation points. From the real depth-averaged model simulation results, it was found that the spring tide Higher High Water (HHW) and tidal current speed values at the 4 observation points were about 2.2 m and 1.33 m/s, respectively. The ADCIRC model results were analyzed with reference to the Korea Hydrographic and Oceanographic Agency's (KHOA) observed data for verification. Furthermore, using topographical characteristics via the Tidal Flux Method (TFM), tidal energy density distribution was calculated, indicating a maximum tidal energy density of about $1.75kW/m^2$ for the 5 assessment areas around Uido. The tidal energy density was evaluated with consideration given to topographical characteristics as well as tidal elevation and tidal current speed to determine an optimum tidal farm candidate.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.254-269
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• 2020

The purpose of this study is to propose guidance for wall renewal that is appropriate for an ancient city wall through application of advanced research and theories in wall design. It is a streetscape improvement project which forms part of the "Ancient City Image Finding Project". Study methods consist of advanced research classification, wall design theory contemplation, and analysis of the significance of designated ancient city areas and the "Ancient City Image Finding Project" status. Based on these methods, case study candidates were selected, case status and problems were identified, and improvement proposals were analyzed by comparing various features. Advanced wall research was classified into six categories including analysis of wall characteristics; wall design principle applications; wall structure, color, shape, and application; modern reinterpretation; palace walls; and house, temple, and village walls. The wall is an element of the streetscape improvement component of the "Ancient City Image Finding Project", with the characteristic of providing preceding experience in visual and cognitive awareness than interior structure. Case candidates for ancient city wall improvement are based on the composition distribution of the special conservation district in each ancient city as well as the conservation promotion district. Ultimately, the surrounding village of Gongju-si Geumseong-Dong Songsanri-gil, adjacent to the Royal Tomb of King Muryeong, was selected as the candidate. The "Ancient City Image Finding Project" of the surrounding village of Gongju-si Geumseong-Dong Songsanri-gil began with new Hanok construction. However, wall maintenance did not begin concurrently with that new Hanok construction. Support and maintenance took place afterwards as an exterior maintenance project for roadside structures. If the Hanok and wall were evaluated and constructed at the same time, the wall would have been built in unison with the size and design of the Hanok. The layout of the main building and wall of the Hanok is deemed to be a structure that is closed tightly because of its spatial proximity and tall height. Songsan-ri-gil's wall design should create a calm, subtle, and peaceful atmosphere with shapes, colors, and materials that express ancient city characteristics, but it is in an awkward position due to its sharpness and narrowness. The cause of the problem at Gongju-si Geumseong-dong Songsanri-gil, the case candidate, is that it is lacking significantly in terms of the aesthetic factors that traditional walls should possess. First, aesthetic consciousness seems to have disappeared during the selection and application process of the wall's natural materials. Second, the level of completion in design and harmony is absent. Maintenance guidance after analyzing the cause of problems in ancient city wall maintenance at Gongju-si Geumseong-dong Songsanri-gil, the subject area of research, is as follows: First, the Hanok design and layout of the wall and main gate should be reviewed simultaneously. Second, the one-sided use of natural stone wall in the Hanok wall design should be reexamined. Third, a permanent system to coordinate the opinions of citizens and experts during the planning and design phases should be employed. Fourth and finally, the Hanok's individuality shall be collectivized and its value as a cultural asset representing the identity of the community shall be increased.

• Journal of KIISE:Information Networking
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• v.37 no.3
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• pp.175-186
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• 2010

Due to the emergence of new application programs and the fast growth of Internet users, Internet routers are required to provide the quality of services according to the class of input packets, which is identified by wire-speed packet classification. For a pre-defined rule set, by performing multi-dimensional search using various header fields of an input packet, packet classification determines the highest priority rule matching to the input packet. Efficient packet classification algorithms have been widely studied. Tuple pruning algorithm provides fast classification performance using hash-based search against the candidate tuples that may include matching rules. Bloom filter is an efficient data structure composed of a bit vector which represents the membership information of each element included in a given set. It is used as a pre-filter determining whether a specific input is a member of a set or not. This paper proposes new tuple pruning algorithms using Bloom filters, which effectively remove unnecessary tuples which do not include matching rules. Using the database known to be similar to actual rule sets used in Internet routers, simulation results show that the proposed tuple pruning algorithm provides faster packet classification as well as consumes smaller memory amount compared with the previous tuple pruning algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.164-173
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• 2014

In underwater robotics, vision would be a key element for recognition in underwater environments. However, due to turbidity an underwater optical camera is rarely available. An underwater imaging sonar, as an alternative, delivers low quality sonar images which are not stable and accurate enough to find out natural objects by image processing. For this, artificial landmarks based on the characteristics of ultrasonic waves and their recognition method by a shape matrix transformation were proposed and were proven in Part 1. But, this is not working properly in undulating and dynamically noisy sea-bottom. To solve this, we propose a framework providing a selection phase of likelihood candidates, a selection phase for final candidates, recognition phase and tracking phase in sequence images, where a particle filter based selection mechanism to eliminate fake candidates and a mean shift based tracking algorithm are also proposed. All 4 steps are running in parallel and real-time processing. The proposed framework is flexible to add and to modify internal algorithms. A pool test and sea trial are carried out to prove the performance, and detail analysis of experimental results are done. Information is obtained from tracking phase such as relative distance, bearing will be expected to be used for control and navigation of underwater robots.

• Korean Journal of Social Welfare
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• v.65 no.2
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• pp.103-130
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• 2013

Although both ecosystem theory and empowerment have become the most prevalent candidate for integrated paradigm for social welfare practices, they could not overcome completely the long-standing and sharp divides between micro and macro practices, that is, between subject and structure as a main explanatory element in social welfare realm. Along with such traditional dualism and tension, a new emerging divide between modernism and postmodernism regarding intrinsic mission and roles of social welfare has urged strongly to develop the overarching theoretical framework for social welfare practice. In this regard, this study aims to recast the ecosystem theory and empowerment through the reflexive modernization theory of critical sociologist Anthony Giddens. With relatively strong emphasis on human capability coined as the reflexivity, Giddens's own creative theory of modernization can be thoroughly expected to provide a solid foundation of integrated paradigm enough to bridge the existing dualisms in social welfare theory and practice. Especially, his unique account of integrated way of how human agency is involved in the construction of social structure and how to transform each other recursively has profound implication for empowerment to be adequate and proper comprehensive framework for social welfare practice.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.2
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• pp.58-69
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• 2013

This research try to review about individuals' living culture place by record to before process of transition and modify of Bugundang village's forest in Itaewon. A result is as follows. First, Itaewon Bugundang is located in highest site of center building of twon forest, it has been preserve by double fence and taboo subject. Physical element of village forest is a factor which give sanctity of Buhundang. Second, it is connecting Namsan and Yongsan Family Park as green space. Also Itaewon Bugundang isolated from the current residential area. but in the past, the main beliefs and rituals of its area are responsible for a diverse community where public service was strong. Itaewon Bugundang have played a role presenting a local taboos and social norms. Therefore, these elements of the local community have the traditional cultural values. Third, Zelkova and Kalopanax pictus need to be preserved the value by the Seoul Metropolitan Government. Fourth, components of Bugundang are built by Hwajucheong, Dangjigi house, seonangdan, monument, fence, masonry and various trees. And the function and role of each of these elements remains as traditional culture. And the structural features of historic architectural properties has the value as a registered cultural properties. Fifth, due to these features, the traditional landscape of Itaewon bugundang play a role succeeding disappearing traditional culture and is worth as a potentially valuable landscape elements. This study has significance to the excavation community tradition disappearing landscape and excavation of candidate new tradition.