• ETRI Journal
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• v.36 no.3
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• pp.460-468
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• 2014

This paper addresses the problem of joint time of arrival (TOA) and direction of arrival (DOA) estimation in impulse radio ultra-wideband systems with a two-antenna receiver and links the joint estimation of TOA and DOA to the sparse representation framework. Exploiting this link, an orthogonal matching pursuit algorithm is used for TOA estimation in the two antennas, and then the DOA parameters are estimated via the difference in the TOAs between the two antennas. The proposed algorithm can work well with a single measurement vector and can pair TOA and DOA parameters. Furthermore, it has better parameter-estimation performance than traditional propagator methods, such as, estimation of signal parameters via rotational invariance techniques algorithms matrix pencil algorithms, and other new joint-estimation schemes, with one single snapshot. The simulation results verify the usefulness of the proposed algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.9
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• pp.2284-2298
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• 2013

In this paper, a fast and efficient signal reconstruction algorithm for solving the basis pursuit (BP) problem in compressed sensing (CS) is proposed. This fast linearized Bregman method (FLBM), which is inspired by the fast method of Beck et al., is based on the fact that the linearized Bregman method (LBM) is equivalent to a gradient descent method when applied to a certain formulation. The LBM requires $O(1/{\varepsilon})$ iterations to obtain an ${\varepsilon}$-optimal solution while the FLBM reduces this iteration complexity to $O(1/\sqrt{\varepsilon})$ and requiring almost the same computational effort on each iteration. Our experimental results show that the FLBM can be faster than some other existing signal reconstruction methods.

• Korean Journal of Culture and Social Issue
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• v.26 no.4
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• pp.551-578
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• 2020

The purpose of this study is to identify the moderating effect of each of the three stress response (problem-centered treatment, pursuit of social support, and positive thinking) in the effect of work-family conflict between dual-earner couples on marriage satisfaction. To this end, 369 married couples (369 wives, 369 husbands) who raise children under the age of 6 were surveyed on stress coping (problem-centered, social support, and positive thinking), work-family conflicts, and marriage satisfaction. Based on the Actor-Partner Interdependence Model (APIM), the collected data verified six research models by distinguishing the moderating effects of each of the three coping strategies from the direction of Work to Family conflict and Family to Work conflict. Interaction graphs were also presented to determine the pattern of significant buffering effects. As a result, first of all, the problem-oriented strategy of the wife buffer the negative impact of the husband's WFC on the husband's own and wife's marriage satisfaction. It was also found that problem-oriented strategy that husband himself uses to buffer the negative impact of the husband's FWC on his wife's marriage satisfaction. Second, the pursuit of social support confirmed that the negative effects of the husband's WFC on the husband's marriage satisfaction were mitigated by the pursuit of social support used by his wife. Third, in the case of positive thinking, the effect of the positive thinking on the husband's WFC on the marriage satisfaction of the husband and wife was shown, and the positive response effect of the wife's FWC conflict was also shown. Finally, based on the results of this study, the discussion and implications of the study were presented.

• Archives of design research
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• v.15 no.2
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• pp.5-18
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• 2002

Recently, the West's interest on Buddhism has been uprising. If the interest on Buddhism is especially from Western intellectuals, it will surely be the motive to change, the future of Western society. Actually, while the West has been interested in the material civilization on the basis of Christianity, the East has been pursuing after the spiritual culture on the basis of Buddhism. However, what does it mean that many of civilized westerners have come to dislike the manner of scientific pursuit and strict rationality which made them wealthy materially\ulcorner It means that they have felt their ideologies which is based on the Christian culture, has met an end or at least they have started to get interested in the Eastern ideology, 'Buddhism'. Particularly, if we agree that industrial design is a field of basis on the stringent rationality, and is a field of applied science on the basis of technology and production, it surely must have rather been influenced by Christian culture than Buddhism. But regardless of material richness by Christian culture, some Western intellectuals'secession from christianity means that their pursuit of material civilization doesn't help much in chasing after human original happiness. Instead, they are charmed by the fact that their mental illness problem, which is the result of the incessant pursuit of materialism, can be salved more 'scientifically'rather by Buddhism than Christianity. Compared with the westerners'spiritual unhappiness by the strong pursuit of material, Buddhism lowers their passion for material and help to lead their lives happily with least'pursuit of materialism. In this sense, I insist that we need to study'Design'from a viewpoint of Buddhist idea.

• Journal of Engineering Education Research
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• v.23 no.3
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• pp.13-19
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• 2020

The purpose of this study is to develop and apply a make-a-thon program based on engineering problem solving for science high school students and to analyze the changes of participating students. Through the consultation of teachers and experts, a team-based and student-driven engineering problem-solving-oriented make-a-thon program was developed. And, the program operated using KAIST's human and material resources for 51 students. Students composed of 12 teams studied 12 topics through an engineering problem-solving process, and the overall program satisfaction was very high, on average 4.62. Through this program, students' creative leader competency have been positively changed, especially in cognitive characteristics (diffusion thinking, problem solving ability) and social characteristics (pursuit of social values). Attitudes toward engineering also changed positively, especially in terms of difficulty of engineering, interest in engineering, gender role in engineering, and engineering and occupational factors. In conclusion, it was confirmed that this program is very effective for science high school students with high demand for engineering education.

• Journal of the Korean Mathematical Society
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• v.33 no.2
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• pp.319-332
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• 1996

Many authors have studied multiple stochastic integrals in pursuit of the existence of product processes in terms of multiple integrals. But there has not been much research into the structure of the product processes themselves. In this direction, a study which gives emphasis on sample path continuity and boundedness properties was initiated in Pyke[9]. For details of problem set-ups and necessary notations, see [9]. Recently the weak limits of U-processes are shown to be chaos processes, which is product of the same Brownian measures, see [2] and [7].

• Bulletin of the Korean Mathematical Society
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• v.57 no.1
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• pp.127-131
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• 2020

We discuss two unrelated topics regarding Cops and Robbers, a well-known pursuit-evasion game played on a simple graph. First, we address a recent question of Breen et al. and prove the PSPACE-completeness of the cop throttling number, that is, the minimal possible sum of the number k of cops and the number capt(k) of moves that the robber can survive against k cops under the optimal play of both sides. Secondly, we revisit a teleporting version of the game due to Wagner; we disprove one of his conjectures and suggest a new related research problem.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.18-20
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• 2021

In order to prevent collision accidents of ships, which has been increasing recently, research on artificial intelligence-based autonomously operated ships (Maritime Autonomous Surface Ship, MASS) is underway. However, most of the studies related to autonomous ships mainly target medium-to-large ships due to the size and cost of the autonomous navigation system, and the sensors used here have a problem in that it is difficult to mount them on small ships. Therefore, this paper provides a path tracking system equipped with GPS and IMU sensors for autonomous operation of small ships. GPS and IMU sensors are utilized to determine the exact position of the vessel, which allows the proposed system to manually control the small vessel model to create a path and then when the small vessel travels the same path. Use the Pure Pursuit algorithm to follow the path. As a result, In this research, it is expected that a lightweight and low-cost sensor can be used to develop an autonomous operation system for small ships at low cost.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.195-214
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• 2016

Monitoring of impact loads is a very important technique in the field of structural health monitoring (SHM). However, in most cases it is not possible to measure impact events directly, so they need to be reconstructed. Impact load reconstruction refers to the problem of estimating an input to a dynamic system when the system output and the impulse response function are usually known. Generally this leads to a so called ill-posed inverse problem. It is reasonable to use prior knowledge of the force in order to develop more suitable reconstruction strategies and to increase accuracy. An impact event is characterized by a short time duration and a spatial concentration. Moreover the force time history of an impact has a specific shape, which also can be taken into account. In this contribution these properties of the external force are employed to create a sample-force-dictionary and thus to transform the ill-posed problem into a sparse recovery task. The sparse solution is acquired by solving a minimization problem known as basis pursuit denoising (BPDN). The reconstruction approach shown here is capable to estimate simultaneously the magnitude of the impact and the impact location, with a minimum number of accelerometers. The possibility of reconstructing the impact based on a noisy output signal is first demonstrated with simulated measurements of a simple beam structure. Then an experimental investigation of a real beam is performed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1700-1721
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• 2017

The problem of blocking artifacts is very common in block-based image and video compression, especially at very low bit rates. In this paper, we propose a post-processing method for JPEG-coded image deblocking via sparse representation and adaptive residual threshold. This method includes three steps. First, we obtain the dictionary by online dictionary learning and the compressed images. The dictionary is then modified by the histogram of oriented gradient (HOG) feature descriptor and K-means cluster. Second, an adaptive residual threshold for orthogonal matching pursuit (OMP) is proposed and used for sparse coding by combining blind image blocking assessment. At last, to take advantage of human visual system (HVS), the edge regions of the obtained deblocked image can be further modified by the edge regions of the compressed image. The experimental results show that our proposed method can keep the image more texture and edge information while reducing the image blocking artifacts.