• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.649-656
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• 2003

In this paper we confirm the relation between the phase and phase error of the beat signal at the lock-in region of the dither type ring laser gyroscope by numerical calculation. We also study the requirement of the dither noise of an amplitude modulation type for statistical zero averaging of the beat signal phase error, without accumulation. As a result, we find that the dither noise requires the increase and decrease gradients of the dither amplitude, and those gradients should be combined with similar white noise. The slope of the gradient and maximum/minimum amplitude must be changed randomly. We confirm the error accumulation characteristic related to the dither noise by comparison of the two outputs during temperature change, by operating the two kinds dither noise, one is satisfied with the requirement and the other is not.

• Journal of agricultural medicine and community health
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• v.46 no.3
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• pp.144-152
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• 2021

Objectives: We did this study to summarize and review and charcterize the community-wide early response to COVID-19 in Dongnae-gu of Busan Metropolitan City where first confirmed case of COVID_19 occurred in Busan. Methods: Research team from college of medicine participated as advisor to response team of local government. Research team consulted and educated and interviewed response team and wrote and reviewed COVID-19 white paper of local government. Results: Political commitment of District mayor made possible community-wide co-operation between public-private section. Early mobilization of District-wide resource was possible through political commitment. Whole-of-government response developoed to whole-of-society approach including economic support. Conclusions: Proactive community-wide response were mobilized under commitment of city mayor of local government to address the first CIVID-19 incidence in Busan Metropolitan City.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.460-465
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• 2021

In active sonar, time delay estimation is used to find the distance between the target and the sonar. Among the time delay estimation methods for active sonar, estimation in the frequency domain is widely used. When estimating in the frequency domain, the time delay can be thought of as a frequency estimator, so it can be used relatively easily. However, this method is prone to rapid increase in error due to noise. In this paper, we propose a new method which applies weighted dictionary and sparsity in order to reduce this error increase and we extend it to two receivers to propose an algorithm for estimating the time delay between two receivers. And the case of applying the proposed method and the case of not applying the proposed method including the conventional frequency domain algorithm and Generalized Cross Correlation-Phase transform (GCC-PHAT) in a white noise environment were compared with one another. And we show that the newly proposed method has a performance gain of about 15 dB to about 60 dB compared to other algorithms.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.339-345
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• 2021

In this paper, estimation angle performance analysis of amplitude-comparison monopulse radar under additive noise effect is dealt with. When uncorrelated white noises are added to the squinted beams, the angle estimation performance is analyzed through the mean square error(MSE). The numerical integration-based mean square error result completely overlaps the Monte Carlo-based mean square error result, which corresponds to 99.8% of the Monte Carlo-based mean square error result. In addition, the mean square error analysis method based on numerical integration has a much faster operation time than the mean square error method based on Monte Carlo. the angle estimation performance of the amplitude comparison monopulse radar can be efficiently analyzed in various noise environments through the proposed numerical integration-based mean square error method.

• Cross-Cultural Studies
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• v.23
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• pp.243-264
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• 2011

The results of 2000 Population Census explains the context of a series of incidents happening in the Latino television broadcasting market recently. That is, the rapid growth of Latino population so fast as overtaking the Black population has needed media as a means of Latino's own social interests and communication. In this context, the television broadcasting market as a marketing means of capitals targeting for the Latinos has experienced more rapid changes. In other words, there has been some changes in the Latino television broadcasting market which divided by two major networks, Univision and Telemundo. It was 1970s when Latino media started to be considered as an important framework to understand the problems of the Latinos in American society. Experiencing the human rights movement of the 1960s, the Latino communities' sense of identity realized the importance of media as an expression of themselves from the interest on the factors which directly determine the quality of their life such as the immigration, education, health, and employment. The anglo media plays a role in introducing the Latinos and forming the images of the Latinos to the non-Latinos. It can be possible to criticize that the anglo media propagates the unilateral image of the Latinos by the mainstream white society, the stereotyped images of the Latinos. The spanish media targeting for the Latinos has grown continuously, combining the inside needs of forming the identity of the Latinos and communication and outside needs of commercialism. On the other hand, the needs for the programs based on the American Latinos has been increased, along with the increase of the Latino media based on the dual languages or English. This paper reviewed the history of the Latino media briefly, and then examined the relationship between the Latinos and the media through the television broadcasting which influence the Latino's everyday life enormously.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.7-11
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• 2019

Due to diversification and popularization of devices that use rapid transmission, there are many security issues related to radio waves. As the disturbance and interference of the radio wave can cause a direct inconvenience to a life, it is a very important issue. In this paper, as a means to prevent radio disturbance and interference, the projected image of the reference grid and the deformed grid is obtained by measuring the projected $moir{\acute{e}}$ using the white light source, projecting grid and the light source, and a $moir{\acute{e}}$ pattern is generated with an image processing algorithm by applying a phase diagram algorithm, and generated $moir{\acute{e}}$ pattern phase diagram creates a three-dimensional shape. By making an encrypted token using this measured face shape, the transmission of the information through token ring is determined in order to transmit the horizontal transmission having the dynamic security characteristics which includes authentication strength and caller information, etc. And by confirming the uniqueness of the token and by sending and receiving the horizontal transmission using java serialization and deserialization function, a problem solving method is suggested.

• Journal of Chest Surgery
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• v.52 no.4
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• pp.191-194
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• 2019

The Korean Society for Thoracic and Cardiovascular Surgery (KTCVS) was founded in 1968 and celebrated the 50th anniversary of its founding in 2018. The launch of the KTCVS may seem somewhat recent, given that the American Association for Thoracic Surgery was founded in 1917. However, considering the circumstances of the Korean medical community after the Japanese occupation (1910-1945), World War II (1940-1945), and the Korean War (1950-1953), this apparent delay is understandable. Even before the foundation of the KTCVS, the early pioneers of thoracic and cardiovascular surgery promptly adopted medical technologies from more advanced countries such as the United States, and contributed significantly to both cardiac and thoracic surgery despite difficult circumstances. In 2012, before the 50th anniversary of the founding of the KTCVS, members shared the opinion that objective records of the activities of the early pioneers should be identified and preserved, and reacted positively towards the necessity for historians who would preserve such records. With this background, the Historical Records Preservation Committee of the KTCVS (hereinafter, referred to as 'the Committee') was launched. The Committee published a white paper on the history of thoracic and cardiovascular surgery in 2015 and held an exhibition of the achievements of the pioneers at the 50th anniversary of the founding of the KTCVS. The Committee also published a book entitled "The history of Korean thoracic surgery with photographs: celebrating the 50th anniversary of the society." The Committee will keep making efforts to find and preserve materials related to activities during the early development of thoracic and cardiovascular surgery in Korea.

• Journal of IKEEE
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• v.23 no.3
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• pp.934-940
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• 2019

In this paper, we propose a Reverse Differential Chaos Shift Keying (RE-DCSK) system for low cost, high reliability and high data rate non-coherent chaos communication .In RE-DCSK, reference signals are transmitted in the first slot as in the conventional differential chaos shift modulation scheme (DCSK) and in the second slot a time inversion block strengthens the autocorrelation of the chaos signal and uses the orthogonality of the two signals to obtain the information signal. RE-DCSK enables relatively double the data rate compared to DCSK and also improves the security of communications without any additional cost of system complexity.To prove its effectiveness, we analyze it through Rayleigh fading channel and additional white Gaussian noise (AWGN) channel based on the derived BER expression. The BER performance of the proposed system is improved when compared with the CDSK and DCSK system using AWGN channel.

• Journal of IKEEE
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• v.23 no.3
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• pp.910-916
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• 2019

Non-local similarity of natural images is one of highly exploited features in various applications dealing with images. Unique edges, texture, and pattern of the images are frequently repeated over the entire image. Once the similar image blocks are classified into a cluster, representative features of the image blocks can be extracted from the cluster. The bigger the size of the cluster is the better the additive white noise can be separated. Denoising is one of major research topics in the image processing field suppressing the additive noise. In this paper, a denoising algorithm is proposed which first clusters the noisy image blocks based on similarity, extracts the feature of the cluster, and finally recovers the original image. Performance experiments with several images under various noise strengths show that the proposed algorithm recovers the details of the image such as edges, texture, and patterns while outperforming the previous methods in terms of PSNR in removing the additive Gaussian noise.

• Smart Structures and Systems
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• v.24 no.3
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• pp.333-343
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• 2019

The possibility of adopting vibration-powered wireless nodes has been largely investigated in the last years. Among the available technologies based on the piezoelectric effect, the most common ones consist of a vibrating beam covered by electroactive layers. Another energy harvesting strategy is based on the use of piezoelectric strips attached to a hosting structure subjected to dynamic loads. The hosting structure, for example, can be the system to be equipped with wireless nodes. Such strategy has received few attentions so far and no analytical studies have been presented yet. Hence, the original contribution of the present paper is concerned with the development of analytical solutions for the electrodynamic analysis and design of piezoelectric polymeric strips attached to relatively large linear elastic structural systems subjected to random vibrations at the base. Specifically, it is assumed that the dynamics of the hosting structure is dominated by the fundamental vibration mode only, and thus it is reduced to a linear elastic single-degree-of-freedom system. On the other hand, the random excitation at the base of the hosting structure is simulated by filtering a white Gaussian noise through a linear second-order filter. The electromechanical force exerted by the polymeric strip is negligible compared with other forces generated by the large hosting structure to which it is attached. By assuming a simplified electrical interface, useful new exact analytical expressions are derived to assess the generated electric power and the integrity of the harvester as well as to facilitate its optimum design.