• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.9
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• pp.907-915
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• 2002

In this paper, a compact digital phase shifter to be used an active phased array antenna system for satellite communications was proposed. The even and odd mode analysis for a given reflection-type phase shifter, which uses a folded hybrid coupler as a base element, was performed and the design parameters were derived. Also, to verify experimentally the electrical performances of the proposed structure, X-band 4-bit digital phase shifter was designed and fabricated using Teflon soft substrate $({\varepsilon}_r; =\;2.17)$. Its circuit size was less than 3.5 cm $\times$ 3.0 cm, and it exhibited at least 50 % size reduction as compared with the conventional unfolded configuration. The experimental results of the fabricated phase shifter showed that the average insertion loss and insertion loss variation were less than 3.5 dB, $\pm$ 0.6 dB within the operating band, 7.9 ~ 8.4 GHz, respectively. And, input and output return loss were more than 10 dB, respectively. Also, the phase response of the phase shifter showed 4-bit operation with $\pm$3$^{\circ}$ rms phase error.

• Journal of Digital Contents Society
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• v.19 no.6
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• pp.1213-1218
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• 2018

Recently introduced Mask R - CNN presents a conceptually simple, flexible, general framework for instance segmentation of objects. In this paper, we propose an algorithm for efficiently searching objects of images, while creating a segmentation mask of heat generation part for an instance which is a heating element in a heat sensed image acquired from a thermal infrared camera. This method called a mask R - CNN is an algorithm that extends Faster R - CNN by adding a branch for predicting an object mask in parallel with an existing branch for recognition of a bounding box. The mask R - CNN is added to the high - speed R - CNN which training is easy and fast to execute. Also, it is easy to generalize the mask R - CNN to other tasks. In this research, we propose an infrared image detection algorithm based on R - CNN and detect heating elements which can not be distinguished by RGB images. As a result of the experiment, a heat-generating object which can not be discriminated from Mask R-CNN was detected normally.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.379-388
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• 2007

This paper presents a real-time respiration and heartbeat detector comprised of a 1.6 GHz single-channel Doppler sensor and analog/digital signal processing block for remote vital sign detection. The RF front end of the Doppler sensor consists of an oscillator, mixer, low noise amplifier, branch-line hybrid and patch antenna. We apply artificial transmission lines(ATLs) to the branch-line hybrid, which leads to a size reduction of 40 % in the hybrid, while its performance is very comparable to that of a conventional hybrid. The analog signal conditioning block is implemented using second order Sallen-Key active filters and the digital signal processing block is realized with a LabVIEW program on a computer. The respiration and heartbeat detection is demonstrated at a distance of 50 cm using the developed system.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.151-171
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• 2023

For the efficient establishment of a channel strategy for banks, this study aims to propose a channel model by classifying channels into types, and carrying out a correspondence analysis per type. A survey of bankers was conducted to visualize categorical data and create a positioning map. As a result, first, 12 banking channels were classified into 4 types based on business processing subjects and places, which were then, further grouped into the categories of full-banking and self-banking. Second, a correspondence analysis according to the classified types was carried out, and it was found that the branch-type is suitable for product description and customer management, while the banking-type is suitable for efficient business processing without time and space constraints. Furthermore, the analysis also showed that the machine-type and banking-type are inappropriate for customer management, and the mobility-type demonstrates low operational effectiveness due to a lack of awareness. The aforementioned findings suggest the need for a hybrid convergence channel that reflects the characteristics of banking tasks and fills in the gaps between the different channels. Third, a channel model was derived by adding a common area to the 2×2 model consisting of the business processing subjects and places. Therefore, this study is meaningful in that it examines the diversification of channels and factors in the division of roles by channel type based on customers' banking channel selection factors, and presents basic research findings for future channel strategy establishment and efficient channel operation.

• The Journal of the Korea Contents Association
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• v.17 no.12
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• pp.34-48
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• 2017

The narratives of the digital age have attempted interactions, and the interactive storytelling represented by the Branch Narratives has a problem of the expensive production cost of many optional implementations and poor narrative compared to linear story. As an alternative to this, this study proposes a user-oriented storytelling using user's personality traits. Using the Enneagram, a model of human psyche, and the Actantial model of the semiotician Greimas, when stories and characters are the same, the story could be reconstructed by deriving different topics from the same story according to the user's Enneagram personality type. The theme is determined by defining the axis of the desire of the Actantial model by respectively setting the character with the user's Enneagram type as the subject and the core value in the type as the object. The axis of Power could be defined by the stress and security points in Enneagram. In this way, we can derive the themes of 9 Enneagram types and the corresponding Actantial model and make plots. The users will appreciate one of these reconstructed plots in different perspectives and themes, depending on their personality type. In this study, we applied the above methodology to the story of the pansori novel "Tokkijeon". User-centered storytelling is a new attempt to predict user's choice and reconstruct the story based on the user's personality and perspective.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.78-89
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• 1999

In this paper, to improve bandwidth amplitude fluctuation for the broadband signal in indoor propagation environment, we measured and analyzed broadband signal using a vertically polarized, horizontally polarized and circularly polarized antenna, conducting by frequency sweeping method in NLOS (Non-Line-of-Sight) environment. And, to investigate the optimum condition for the improvement of broadband propagation characteristics we also examined the effects of both human motions and transmission antenna height in the NLOS environment. As a result, in the case of NLOS environment, it was found that the amplitude deviation characteristics in frequency bandwidth can be improved by polarization diversity reception. Especially, we found that it is the best effective one to make polarization diversity reception branches, which install the circularly polarized antenna at transmitting end and install the polarized diversity branches received vertical or/and horizontal polarized wave at receiving end. The affection of a human motions is not so much in LOS and NLOS environment, but it can lead to the cause of burst error in indoor digital radio communications as the fade of signal strength become more deeper. And also, when raise the transmitting antenna up to the ceiling, the LOS and NLOS environment could be coexisted. In this case, it can be also inferred that frequency bandwidth amplitude deviation must be fundamentally improved by using polarization diversity reception technique to make the possibility of high transmission rate.