• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.136-141
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• 2024

In this paper, a broadband inset-fed microstrip patch antenna operating at 10.525 GHz band was proposed. The proposed broadband inset-fed microstrip patch antenna consists of three narrow rectangular patches. At the center of the center patch, two symmetrical side patches were connected by a strip conductor and were arranged with their centers shifted in a perpendicular direction with respect to the center patch. For performance comparison, a conventional inset-fed square microstrip patch antenna was designed. Experiment results show that the frequency band of the measured input reflection coefficient with a voltage standing wave ratio less than 2 for the broadband inset-fed microstrip patch antenna was 10.036-11.051 GHz (9.63%), whereas that for the conventional inset-fed rectangular microstrip patch antenna was 10.306-10.772 GHz (4.42%). Therefore, the input reflection coefficient frequency bandwidth of the fabricated broadband inset-fed microstrip patch antenna was increased by 2.18 times, compared to the conventional inset-fed square microstrip patch antenna.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.815-820
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• 2023

In this paper, the design method of a miniaturized chipless RFID tag using a modified bent H-shaped slot was proposed. The proposed modified bent H-shaped slot was appended on the rectangular conductor plate printed on one side of a 20 mm × 50 mm FR4 substrate with a thickness of 0.8 mm. The resonant dip frequency of the bistatic RCS for the proposed modified bent H-shaped slot was compared with the cases when the H-shaped, U-shaped slot, and bent H-shaped slots were added, respectively, on the conductor plate. The simulated resonant dip frequencies for H-shaped, U-shaped, and bent H-shaped slots were 5.907 GHz, 4.918 GHz, and 4.364 GHz, respectively. When the proposed modified bent H-shaped slot was added, the resonant dip frequency was decreased to 3.741 GHz, and, therefore, the slot length was reduced by 36.7% compared to the H-shaped slot case. Experiment results show that the resonant dip frequency of the fabricated modified bent H-shaped slot was 3.9 GHz.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.301-307
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• 2024

This study introduces a novel cascade fusion architecture aimed at enhancing thermal images across various scale conditions. The processing of thermal images at multiple scales has been challenging due to the limitations of existing methods that are designed for specific scales. To overcome these limitations, this paper proposes a unified framework that utilizes cascade feature fusion to effectively learn multi-scale representations. Confidence maps from different image scales are fused in a cascaded manner, enabling scale-invariant learning. The architecture comprises end-to-end trained convolutional neural networks to enhance image quality by reinforcing mutual scale dependencies. Experimental results indicate that the proposed technique outperforms existing methods in multi-scale thermal image enhancement. Performance evaluation results are provided, demonstrating consistent improvements in image quality metrics. The cascade fusion design facilitates robust generalization across scales and efficient learning of cross-scale representations.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.625-632
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• 2024

This paper analyzed the changes in the curriculum of computer and software-related majors that educate the core ICT technologies needed for the 4th Industrial Revolution, before and after the COVID-19 pandemic. According to the standard classification of university education units, 172 majors classified into Applied Software Engineering, Computer Science·Computer Engineering, and Artificial Intelligence Engineering were targeted, and the curricula of 2023 and 2019 were compared and analyzed. As a result of the analysis, the introduction of the related curriculum for each curriculum group increased by about 2.6%p before and after the COVID-19 pandemic (2023 84.2%, 2019 81.6%). and the 4th Industrial Revolution response index increased by 9.5 points (37.0 in 2023, 27.5 in 2019)

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.515-522
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• 2024

Energy consumption is steadily increasing, and buildings in particular account for more than 20% of the total energy consumption around the world. As an effort to cost-effectively manage the energy consumption of buildings, many research groups have recently focused on Smart Building Energy Management Systems (BEMS), which are deepening the research depth by applying artificial intelligence(AI). In this paper, we propose a reinforcement learning-based energy control method for smart energy buildings integrated with V2G station, which aims to reduce the total energy cost of the building. The results of performance evaluation based on the energy consumption data measured in the real-world building shows that the proposed method can gradually reduce the total energy costs of the building as the learning process progresses.

• Journal of Advanced Navigation Technology
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• v.28 no.3
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• pp.356-361
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• 2024

This paper deals with the design and fabrication of a coplanar waveguide (CPW)-fed super-wideband semicircular-disk-shaped dipole antenna operating in a frequency band of 2.4 GHz or higher. To feed the antenna, a CPW feed line was appended to the center of the lower arm of the semicircular-disk-shaped dipole antenna. For miniaturization, square patches were added to the ends of the two arms of the semicircular-disk-shaped dipole, whereas the slot width of the CPW feed line at the center of the dipole antenna was increased to improve impedance matching in the 5.4-6.3 GHz band. The simulated frequency band of the proposed antenna for a voltage standing wave ratio (VSWR) less than 2 was 2.369-30 GHz(170.7%), whereas the fabricated antenna was maintained VSWR less than 2 in the frequency range of 2.378-20 GHz when measured using a network analyzer operating up to 20 GHz so it can be applied as a super-wideband antenna for next-generation mobile communications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.2
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• pp.93-98
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• 2024

With the rapid advance in AI (artificial intelligence) and high-performance computing technologies, deep learning is being used in various fields. Deep learning proceeds training by randomly reading a large amount of data and repeats this process. A large number of files are randomly repeatedly referenced during deep learning, which shows different access characteristics from traditional workloads with temporal locality. In order to cope with the difficulty in caching caused by deep learning, we propose a new sampling method that aims at reducing the randomness of dataset reading and adaptively operating on existing buffer cache algorithms. We show that the proposed policy reduces the miss rate of the buffer cache by 16% on average and up to 33% compared to the existing method, and improves the execution time by up to 24%.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.232-237
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• 2024

In this paper, a broadband double dipole quasi-Yagi antenna using a 4×2 meander line array structure for maintaining 8 dBi gain was studied. The 4×2 meanderline array structure consists of a unit cell in the shape of a meanderline conductor, and it was placed above the second dipole antenna of the double dipole quasi-Yagi antenna. A double dipole quasi-Yagi antenna with generally used multiple strip directors was designed on an FR4 substrate with the same size, and the input reflection coefficient and gain characteristics were compared. Comparison results showed that the impedance frequency bandwidth increased by 6.3% compared to when using the multiple strip directors, the frequency bandwidth with a gain of 8 dBi or more increased by 10.1%, and average gain also slightly increased. The frequency band of the fabricated antenna for a voltage standing wave ratio less than 2 was 1.548-2.846 GHz(59.1%), and gain was measured to be more than 8 dBi in the 1.6-2.8 GHz band.

• The Journal of the Acoustical Society of Korea
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• v.43 no.3
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• pp.261-269
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• 2024

In this paper, the acoustic performance of an absorptive silencer was enhanced by optimizing an arrangement of multi-layered absorbing materials. The acoustic performance of the silencer was evaluated through transmission loss, and finite element method-based numerical analysis program was employed to calculate the transmission loss. Polyurethane, a porous elastic material frequently used in absorptive silencers, was employed as the absorbing material. The Biot-Allard model was applied, assuming that air is filled inside the polyurethane. By setting the frequency range of interest up to the 2 kHz and the acoustic performance affecting properties of the absorbing materials were investigated when it was composed as a single layer. And the acoustic performance of the silencers with the single and multi-layered absorbing materials was compared with each other based on polyurethane material properties. Subsequently, the arrangement of the absorbing materials was optimized by applying the Nelder-Mead method. The results demonstrated that the average transmission loss improved compared to the single-layered absorptive silencer.

• Journal of The Korean Institute of Defense Technology
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• v.5 no.1
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• pp.7-18
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• 2023

The military leader makes an operation plan to accomplish combat missions. The current doctrine for an operation planning requires the use of simple and clear procedures and methods that can be carried out with human effort under adverse conditions in the field. The work in the process of an operation planning can be said to be a series of decision-making, and the criteria for decision-making generally apply mission variables. However, detailed standards are not fixed as doctrine, but are creatively established and applied. However, for AI-based decision-making, it is necessary to formalize the criteria and the format used. This paper first aims to standardize various criteria and forms to present a method that can be used in a semi-automated assist system, and to seek a plan to artificialize it. To this end, mathematical models and decision-making methods established in the field of operations research were applied to improve efficiency.