• Journal of the Institute of Convergence Signal Processing
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• v.9 no.1
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• pp.24-30
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• 2008

In this paper we analyze the performance of an adaptive sector cell system, which is adopted to maintain the traffic balance between sectors and to utilize the cell resources effectively, using the data collected from real channel environments. In the data measurements, we transmitted the QPSK modulated signal with carrier frequency of 1.95GHz and received the signals using the 8x4 array antenna equipped on the top of buildings in the urban area. We analyzed the angular distribution and the delay spread of a user signal and analyzed angular distribution of mobile users in a cell using the collected data. Also, we propose the vector channel modeling using the estimated pdf(probability distribution function) of the analyzing results. Through the proposed channel modeling the improvement of the call blocking rate was analyzed when using the adaptive sector cell system, and computer simulations show that the call blocking rate of the adaptive sector cell system was much lower than that of the fixed sector cell system. Additionally, it shows that the call blocking rate increases severely in the fixed sector cell system while the difference of the call blocking rate was smaller in the adaptive sector cell system, as the user density of the spatial distribution increases.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.3
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• pp.166-172
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• 2022

In this study, we photograph driving obstacle objects such as crosswalks, side spheres, manholes, braille blocks, partial ramps, temporary safety barriers, stairs, and inclined curb that hinder or cause inconvenience to the movement of the vulnerable using electric mobility aids. We develop an optimal AI model that classifies photographed objects and automatically recognizes them, and implement an algorithm that can efficiently determine obstacles in front of electric mobility aids. In order to enable object detection to be AI learning with high probability, the labeling form is labeled as a polygon form when building a dataset. It was developed using a Mask R-CNN model in Detectron2 framework that can detect objects labeled in the form of polygons. Image acquisition was conducted by dividing it into two groups: the general public and the transportation weak, and image information obtained in two areas of the test bed was secured. As for the parameter setting of the Mask R-CNN learning result, it was confirmed that the model learned with IMAGES_PER_BATCH: 2, BASE_LEARNING_RATE 0.001, MAX_ITERATION: 10,000 showed the highest performance at 68.532, so that the user can quickly and accurately recognize driving risks and obstacles.

• Journal of the Institute of Convergence Signal Processing
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• v.24 no.2
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• pp.119-125
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• 2023

In this study, we photograph driving obstacle objects such as crosswalks, side spheres, manholes, braille blocks, partial ramps, temporary safety barriers, stairs, and inclined curb that hinder or cause inconvenience to the movement of the vulnerable using electric mobility aids. We develop an optimal AI model that classifies photographed objects and automatically recognizes them, and implement an algorithm that can efficiently determine obstacles in front of electric mobility aids. In order to enable object detection to be AI learning with high probability, the labeling form is labeled as a polygon form when building a dataset. It was developed using a Mask R-CNN model in Detectron2 framework that can detect objects labeled in the form of polygons. Image acquisition was conducted by dividing it into two groups: the general public and the transportation weak, and image information obtained in two areas of the test bed was secured. As for the parameter setting of the Mask R-CNN learning result, it was confirmed that the model learned with IMAGES_PER_BATCH: 2, BASE_LEARNING_RATE 0.001, MAX_ITERATION: 10,000 showed the highest performance at 68.532, so that the user can quickly and accurately recognize driving risks and obstacles.

• Journal of Digital Convergence
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• v.8 no.3
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• pp.1-17
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• 2010

The purpose of this study was to set up the proper method of corporal punishment. The analysis was based on game theory. Major conclusion were as follows: First, the principle of maximum utility and a rational humane of students were assumed. Second, in the game situation of imperfect information, the actions deserved punishment were done by students and punishment was not done by teachers. Third, in game situation of incomplete information, when the probability of punishment is over 50%, ill actions were done by students. Forth, in game situation of complete information, the actions deserved punishment were not done by students, punishment didn't have to be done by teachers. Fifth, in game situation of complete information, when the written agreement for punishment of teacher-students was carried out, the student's school life satisfaction measurement was improved significantly.

• Korea journal of population studies
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• v.34 no.1
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• pp.179-198
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• 2011

The purpose of this study was to examine relationships between chronic diseases, age, and education in Korea. Logistic regression techniques were used to analyze data from the Korean Longitudinal Study of Ageing (KLoSA), which is a nationally representative sample of Koreans aged 45 years and older. The findings show that probability of having chronic diseases increased with age up to about 74; however, it was reduced for respondents aged 74 years or older. Associations between age and chronic diseases were also differential by education. Less educated Koreans tended to have chronic diseases earlier in their lifetime; however, they were likely to have chronic diseases later in life less than more educated counterparts. The findings suggest that individuals with fewer years of education are at an increased risk of developing chronic diseases earlier in their lifetimes, thereby, leading to a higher rate of mortality at younger ages.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2576-2583
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• 2015

In a full-duplex (FD) wireless cellular network, uplink (UL) users induce the severe inter-user interference to downlink (DL) users. Therefore, a user scheduling that makes a pair of DL user and UL user to use the same radio resource simultaneously influences the system performances significantly. In this paper, we first formulate an optimization problem for user scheduling to minimize the occurrence of outage, aiming to guarantee the quality of service of users, and then we propose a suboptimal user scheduling algorithm with low complexity. The proposed scheduling algorithm is designed in a way where the DL user with a worse signal quality has a higher priority to choose its UL user that causes less interference. Simulation results show that the FD system using the proposed user scheduling algorithm achieves the optimal performance and significantly decreases the outage probability compared with the conventional half-duplex cellular system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1082-1087
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• 2021

In MANET(mobile ad hoc network), Mobility models vary according to the application-specific goals. The most widely used Random WayPoint Mobility Model(RWPMM) is advantageous because it is simple and easy to implement, but the random characteristic of nodes' movement is not enough to express the mobile characteristics of the entire sensor nodes' movements. The random mobility model is insufficient to express the inherent movement characteristics of the entire sensor nodes' movements. In the proposed Stochastic mobility model, To express the overall nodes movement characteristics of the network, the moving nodes are treated as random variables having a specific probability distribution characteristic. The proposed Stochastic mobility model is more stable and energy-efficient than the existing random mobility model applies to the routing protocol to ensure improved performances in terms of energy efficiency.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.765-773
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• 2022

This study is a study on the application of a horizontal excavation machine system to improve constructability. In this study, the structural stability of non-covered temporary facilities was evaluated by comparing field measurements and numerical analysis. In addition, the appropriateness of the measurement results was analyzed by comparing and analyzing the results of numerical analysis with the analysis results applying the Gaussian probability density function to the measurement results. In this study, structural safety and long-term durability of the linkage were analyzed based on numerical analysis. As a result of the study, it was analyzed that the non-open cut method (H.A.S. method) of this study secures structural safety and constructability as the behavior in the actual construction process is more safe than the numerical analysis results, even if the uncertainty of the ground condition is taken into account.

• Journal of Digital Convergence
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• v.21 no.2
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• pp.1-7
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• 2023

This study examines the policy direction for energy self-reliant islands using marine energy. In other words, it was suggested that the environmental characteristics of the ocean should be considered by conducting a strategic marine environmental impact assessment when establishing an energy-independent island project plan. It was also suggested to proceed with preemptive site selection. In particular, it was emphasized that continuous monitoring of the marine environment should be carried out during the construction and operation of the marine energy development project. In addition, I emphasized the need to seek ways to expand marine environmental impact data and to actively participate and support the residents of the island, which is important in promoting self-reliant islands using ocean energy. This can be said to have a high probability of success when the government-led smart grid project group and KEPCO collaborate with each other. The results of the study analyzed through literature review are as follows. First, active participation and support for initiatives led by residents are needed. second,. KEPCO must collaborate with specialized public institutions such as the Smart Grid Project Group. Third, a strategic marine environment impact assessment should be introduced. Fourth, continuous marine environmental impact investigations should be conducted.

• Journal of Industrial Convergence
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• v.21 no.4
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• pp.145-155
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• 2023

The main purpose of this study is to investigate the effect of teacher competence on subject satisfaction and career decision of college students majoring in physical education. From April 1 to April 30, 2022, samples were extracted using pur-posive sampling, which is a non-probability sampling method, for physical education majors attending universities of education in Gyeonggi-do, Chungcheong-do, and Daejeon, etc. 400 study participants were sampled and cross-analysis was performed on the final 340 participants. First, Teacher competency had a significant effect on career decision. Second, teacher competency had a significant effect on career decision. Third, teacher competency had a significant effect on career decision. Fourth, subject satisfaction had a significant effect on career decision. Fifth, a causal relationship was established between teacher competency, subject satisfaction, and career decision. The purpose of this study is to provide basic data for the future career decision of pre-service physical education teachers by investigating the effect of teacher competence on subject satisfaction and career decision of university students majoring in physical education.