• Earthquakes and Structures
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• v.16 no.6
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• pp.715-726
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• 2019

Several municipal seismic vulnerability investigations have been identified pounding of adjacent structures as one of the main hazards due to the constrained separation distance between adjacent buildings. Consequently, an assessment of the seismic pounding risk of buildings is superficial in future adjustment of design code provisions for buildings. The seismic lateral oscillation of adjacent buildings with eccentric alignment is partly restrained, and therefore a torsional response demand is induced in the building under earthquake excitation due to eccentric pounding. In this paper, the influence of the eccentric seismic pounding on the design demands for adjacent symmetric buildings with eccentric alignment is presented. A mathematical simulation is formulated to evaluate the eccentric pounding effects on the seismic design demands of adjacent buildings, where the seismic response analysis of adjacent buildings in series during collisions is investigated for various design parameters that include number of stories; in-plan alignment configurations, and then compared with that for no-pounding case. According to the herein outcomes, the effects of seismic pounding severity is mainly depending on characteristics of vibrations of the adjacent buildings and on the characteristics of input ground motions as well. The position of the building wherever exterior or interior alignment also, influences the seismic pounding severity as the effect of exposed direction from one or two sides. The response of acceleration and the shear force demands appear to be greater in case of adjacent buildings as seismic pounding at different levels of stories, than that in case of no-pounding buildings. The results confirm that torsional oscillations due to eccentric pounding play a significant role in the overall pounding-involved response of symmetric buildings under earthquake excitation due to horizontal eccentric alignment.

• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.125-129
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• 2019

This paper describes the jamming effect of phase-coded pulse compression(PCPC) radar. Barker code radar, a typical PCPC radar, separates transmission pulses into 13 or 31 small pulses and phase modulates and transmits each pulse signal to increase radar detection efficiency and reduce the influence of jamming. Generally, when the radar is subjected to jamming, the detection distance becomes shorter and the detection error rate becomes higher. In the case of noise jamming or carrier jamming on the PCPC radar, the jamming effect is very small for no phase-coded convergence. However, the jamming effect is large in the case of synchronous jamming using the pulse-coded signal as a jamming signal with DRFM. It can be seen that the jamming effect increases when the storage time of the pulse-coded signal is prolonged. This study is considered to be useful for PCPC radar and EW jamming system design.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.5
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• pp.97-108
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• 2018

"Death is the side of life which is turned away from us." The life of people in Seoul, however, is disconnected from death. Why? This article compares the historical changes in the cemetery disposition of Paris and Seoul to answer this question. The cemetery is always a meeting place between the living and the dead. In pre-modern cities, the cemetery was close to the people's daily life. However, the fundamental change of urban structure due to modernization has a great influence on the cemetery. With the advent of the train, the world has shrunk and the city has expanded unprecedentedly. In such a situation, the cemetery is expelled to the outside of the city. However, while Paris and Seoul share the same overall flow, they responded differently to the plans for the establishment of large-scale remote cemeteries. In Paris, the plan was canceled by citizens who value their relationship with the dead. On the other hand, Seoul was unable to manage the cemetery due to social confusion in 20th century. All cemeteries were expelled as industrialization began. As a result, there is no public cemetery or ossuary at present in Seoul. In Seoul, about 20 years ago however, a new kind of place for the dead began to appear. It is an ossuary attached to religious facilities. In other words, the current cemetery of Seoul is divided into two forms : the public cemetery, which is expelled from the city, and the private ossuary, which is attached to religious facilities built in the city.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1039-1045
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• 2021

In modern society, due to the influence of the 4th industrial revolution, camera sensors and image-based automation systems are being used in various fields, and interest in image and signal processing is increasing. In this paper, we propose a digital filter algorithm for image reconstruction in an impulse noise environment. The proposed algorithm divides the image into eight masks in vertical, horizontal, and diagonal directions based on the local mask set in the image, and compares the standard deviation of each segmentation mask to obtain a reference value. The final output is calculated by applying the weight according to the spatial distance and the weight using the reference value to the local mask. To evaluate the performance of the proposed algorithm, it was simulated with the existing algorithm, and the performance was compared using enlarged images and PSNR.

• PNF and Movement
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• v.12 no.2
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• pp.89-96
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• 2014

Purpose: The purpose of this study was to examine the influence of foot angles on plantar pressure and the center of pressure (COP) trajectory length during level walking. Methods: The study subjects were 30 female university students without orthopedic diseases in the foot. The foot angle was divided into three forms (out-toeing, normal, in-toeing). The subjects practiced each type of gait, and then performed each of level walking, three times, and their averages were calculated. A plantar pressure measurement instrument was used, and the maximum force was obtained by dividing the foot into nine regions covering the anterior medial-lateral, middle medial-lateral, and posterior medial-lateral. The COP trajectory length was statistically processed by obtaining medial-lateral, anterior-posterior, and entire travel distance. Results: During normal walking, the maximum force was significantly higher in the anterior lateral than in the other areas, and the COP trajectory length was significantly shorter in the front-back and entire travel distances (p<0.05). During stair climbing. Conclusion: Walking at abnormal foot angles does not cause appreciable problems in the short term as pressure is concentrated on a specific plantar part. However, it becomes the cause of deformed foot structures and can result in musculoskeletal disabilities in the long term. Therefore, a kinesiatrics-based intervention is required to maintain normal foot angles.

• Imaging Science in Dentistry
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• v.51 no.2
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• pp.93-106
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• 2021

Purpose: This study was conducted to review the literature regarding the types of cone-beam computed tomography (CBCT) artifacts around dental implants and the factors that influence their formation. Materials and Methods: A search strategy was carried out in the PubMed, Embase, and Scopus databases to identify published between 2010 and 2020, and 9 studies were selected. The implants included 306 titanium, titanium-zirconium, and zirconia implants, as well as 5 titanium cylinders. Results: The artifacts around the implants were the beam-hardening artifact, the streaking artifact, and band-like radiolucent areas. Some factors that influenced the formation of artifacts were the implant material, bone type, evaluated regions, distance, type of CBCT, field of view (FOV) size, milliamperage, peak kilovoltage (kVp), and voxel size. The beam-hardening artifact was the most widely reported, and it was minimized in protocols with a smaller FOV, larger voxels, and higher kVp. Conclusion: The risk and benefit of these protocols in individuals with dental implants must be considered, and clinical examinations and complementary radiographs play an essential role in implantology.

• Advances in nano research
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• v.10 no.1
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• pp.59-69
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• 2021

Electrospinning is a cost-effective and versatile method for producing submicron fibers. Although this method is relatively simple, at the theoretical level the interactions between process parameters and their influence on the fiber morphology are not yet fully understood. In this paper, the aim was finding optimal electrospinning parameters in order to obtain the smallest fiber diameter by using Taguchi's methodology. The nanofibers produced by electrospinning a solution of Thermoplastic Polyurethane (TPU) in Dimethylformamide (DMF). Polymer concentration and process parameters were considered as the effective factors. Taguchi's L9 orthogonal design (4 parameters, 3 levels) was applied to the experiential design. Optimal electrospinning conditions were determined using the signal-to-noise (S/N) ratio with Minitab 17 software. The morphology of the nanofibers was studied by a Scanning Electron Microscope (SEM). Thereafter, a tensile tester machine was used to assess mechanical properties of nanofibrous scaffolds. The analysis of DoE experiments showed that TPU concentration was the most significant parameter. An optimum combination to reach smallest diameters was yielded at 12 wt% polymer concentration, 16 kV of the supply voltage, 0.1 ml/h feed rate and 15 cm tip-to-distance. An empirical model was extracted and verified using confirmation test. The average diameter of nanofibers at the optimum conditions was in the range of 242.10 to 257.92 nm at a confidence level 95% which was in close agreement with the predicted value by the Taguchi technique. Also, the mechanical properties increased with decreasing fibers diameter. This study demonstrated Taguchi method was successfully applied to the optimization of electrospinning conditions for TPU nanofibers and the presented scaffold can mimic the structure of Extracellular Matrix (ECM).

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.1
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• pp.15-28
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• 2021

As the social distance has been strengthened by the COVID-19 Pandemics, telecommuting has spread, and government agencies have also begun telecommuting since March and are still maintaining a certain level. The Government's remote work service, Government Virtual Private Network (GVPN), which is essential to telecommuting of government agencies, is expected to cause a number of problems with the rapid increase in users in a short period of time. Therefore, a survey and statistical analysis were conducted to analyze the impact of the quality factors of GVPN on the users' satisfaction to the public officials of the government departments who are directly using it, and based on these results, we intend to derive the implications necessary for the improvement of GVPN for remote work in preparation for the full-fledged spread of the non-contact era.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.508-519
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• 2021

In this study, a model was developed to predict the peak particle velocity (PPV) that affects people and the surrounding environment during blasting. Four machine learning models using the k-nearest neighbors (kNN), classification and regression tree (CART), support vector regression (SVR), and particle swarm optimization (PSO)-SVR algorithms were developed and compared with each other to predict the PPV. Mt. Yogmang located in Changwon-si, Gyeongsangnam-do was selected as a study area, and 1048 blasting data were acquired to train the machine learning models. The blasting data consisted of hole length, burden, spacing, maximum charge per delay, powder factor, number of holes, ratio of emulsion, monitoring distance and PPV. To evaluate the performance of the trained models, the mean absolute error (MAE), mean square error (MSE), and root mean square error (RMSE) were used. The PSO-SVR model showed superior performance with MAE, MSE and RMSE of 0.0348, 0.0021 and 0.0458, respectively. Finally, a method was proposed to predict the degree of influence on the surrounding environment using the developed machine learning models.

• Journal of Korea Trade
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• v.26 no.1
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• pp.20-32
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• 2022

Purpose - This paper intends to make theoretical analysis and empirical test on the factors influencing China's export to South Korea, and draw conclusions about China's export efficiency and trade potential. Based on the conclusions, the reasons for China's trade deficit with South Korea are found, and a solution is put forward for solving the problem of China's trade deficit with South Korea. Design/methodology - Based on the data of 2004-2017 years in China, this paper uses the stochastic frontier gravity model to analyze the influencing factors of China's export to South Korea, as well as the export efficiency of each province and the export potential that can be explored. Findings - First, in terms of the factors affecting China's export trade to South Korea, the GDP of the provinces and cities in China, the FDI of South Korea to the provinces and cities in China, the GDP of South Korea, the population and education level of provinces and cities in China can significantly promote the export scale of Chinese provinces and cities to South Korea. The distance between Chinese provincial capitals and the South Korean capital significantly hinders Chinese exports to South Korea; Second, in terms of export trade efficiency, the trade exchange rate of the economically developed cities along the eastern coast of China and several provinces that are close to South Korea is higher than that of the cities in the central and western regions; Third, economic globalization makes trade more convenient, the average export trade efficiency of China's exports to South Korea showed an upward trend. However, under the influence of the 2008 global financial crisis, the export trade efficiency declined from 2008 to 2009, indicating that the impact of the financial crisis on the trade efficiency cannot be ignored. Originality/value - This paper finds out the influencing factors of China's export to South Korea, analyzes the export efficiency of different provinces and cities, excavates the export potential, and puts forward some suggestions for the balanced development of China and South Korea trade in the next step.