• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.960-966
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• 2018

Communication antennas used at sea have been developed remarkably. However, the speed of this development is insufficient when compared with user demands. Therefore, we developed an antenna for UWB/Bluetooth that operates on 3 [GHz] and 5.72 [GHz] bands in order to use the high-speed communication network system which improved antenna miniaturization, gain and radiation patterns. To improve bandwidth, a microstrip patch antenna was selected and CST Microwave Studio 2014 program was used. Through the program, we calculated the slot width, length, transmission line width, etc. using a theoretical formula at each step. These figures were checked through simulation to see if they meet production standards. UWB for high-speed wireless communication for short-range communication at sea, Bluetooth for exchanging information at a short distance by connecting each device, and corresponding technology can be easily utilized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.571-573
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• 2014

In today's technology streaming service's QoS technologiey is an issue. On quality video streaming service there are some technical issues exist, such as buffering. This submission is "Adaptive dual-streaming system design" which is for the integrity of the data streaming that is sent to TCP and UDP for faster transmission of data to the stream. This system provides real-time incoming video encoding in bitrate of h.264-based H through a process based on the video footage of several server and client-to-TCP and UDP via Adaptive providing streaming services in a network environment. This is an unspecified number of buffers in a network environment and continued through the minimization of various streaming for playback of videos and multimedia will be utilized in the field.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.8
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• pp.201-208
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• 2019

Intra-Body Communication (IBC) is a communication method using the human body as a communication medium. The fact that our human body consists of water and electrolyte allow such communication method could work and have strength in low-power. However, because the IBC directly affects to human body by using it as a medium, there was a lack of research in communication protocols of each communication layer. In this paper, we suggests MAC parameters which affects the performance of communication in human body channel, and propose new MAC protocol. Our results shows that our MAC is suitable for supporting high data rate applications with comparable radio duty cycle performance.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.123-128
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• 2019

The structural analysis for light weight on the brake pedal of the racing spec installed with the balance bars of the four models were performed in this study. By utilizing two materials of steels and aluminum alloys, four shapes were analyzed. It is generally assumed that the magnitude of force a person may incur when riding in a car is 1000 N. The fixed points are designated as the parts at which the bolts and pedals are fixed and the mounting part of the balance bar applied by the stress transmitted through the rod when the pressure of the master cylinder rises and the operation stops. Through this analysis study, it is thought that the vulnerability of each brake pedal model can be investigated and the transmission efficiency of the brake pedal can be increased by light weight. As the design data with the durability of brake pedal obtained on the basis of this study result are utilized, the esthetic sense can be shown by being grafted onto the part of car at real life.

• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.125-129
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• 2019

This paper describes the jamming effect of phase-coded pulse compression(PCPC) radar. Barker code radar, a typical PCPC radar, separates transmission pulses into 13 or 31 small pulses and phase modulates and transmits each pulse signal to increase radar detection efficiency and reduce the influence of jamming. Generally, when the radar is subjected to jamming, the detection distance becomes shorter and the detection error rate becomes higher. In the case of noise jamming or carrier jamming on the PCPC radar, the jamming effect is very small for no phase-coded convergence. However, the jamming effect is large in the case of synchronous jamming using the pulse-coded signal as a jamming signal with DRFM. It can be seen that the jamming effect increases when the storage time of the pulse-coded signal is prolonged. This study is considered to be useful for PCPC radar and EW jamming system design.

• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.39-48
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• 2021

Analysis of the change in water content and distribution was conducted according to the supply of recirculation water to a landfill. An excavation sample analysis showed that the recirculation water injection zone had water content 8.8% point higher than that of the non-injection zone, after 8 months of operation. And due to the influence of recirculation water supply by vertical wells in injection zones, the water content increases along with depth more clearly than non-injection zone. According to an electrical specific-resistivity survey after 13 months of operation, the water content got higher towards the bottom of the landfill. The water transmission coefficient is 8.72×10^-4 cm/sec for injection zones and 3.36×10^-5 cm/sec for the intermediate cover layer; analysis shows that the intermediate cover layer may affect the penetration velocity of water supplied by the horizontal injection tube. For the scientific design and operation of re-injection facilities, it was deemed necessary to follow-up research on the residence time and behavior of re-injection water considering the ratio of recirculation water supply in horizontal and vertical tubes, and pitcher coefficient of intermediate and waste layers.

• Food Science and Industry
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• v.50 no.2
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• pp.12-26
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• 2017

Processing steps such as washing and cutting, involved in preparing fresh-cut produce causes tissue damage, leading to rapid quality deterioration. Major defects of fresh-cut produce are discoloration, softening, off-odor development, and microbial growth. Packaging of fresh-cut produce has been changed to reduce these quality problems. Flexible packaging film is widely used to pack fresh-cut produce. Vacuum packaging was the popular packaging method in the beginning of fresh-cut industry in Korea. Vacuum packaging creates high $CO_2$ and low $O_2$ levels to control browning of fresh-cut produce. However, these conditions induce some visual defects and off-odor development. Discoloration problem was also found when fresh-cut produce was packaged with conventional packaging film or plastic tray. Modified atmosphere (MA) packaging is effective for prolonging shelf-life of fresh-cut produce by decreasing $O_2$ and increasing $CO_2$ concentration in the package. Retail MA packaging using different oxygen transmission rate (OTR) film and micro-perforated film has started to be applied to fresh-cut produce in Korea. Proper MA package design that provides optimum range of $O_2$ and $CO_2$ partial pressures is one of the major challenges in the industry. An initial package flushing with $N_2$ or an low $O_2$/high $CO_2$ atmosphere is also used to more rapidly establish steady-state MA condition. Film OTR and $O_2$ flushing affects the fermentative volatile production, off-odor development, electrolyte leakage, discoloration, $CO_2$ injury, microbial population of fresh-cut produce. There is also a demand for convenient packaging to attract consumers. Rigid fresh-cut produce container for retail market has increased since the packaging provides excellent protection from physical damage during transport. Rigid tray used as actual serving vessel for the consumer is increasing in Korea. The tray with flexible lid to wrap or seal fresh-cut produce is more and more gaining popularity. Further practical technology to control quality change and microbial growth for each fresh-cut product has been studied since various fresh-cut items were required. The fresh-cut industry also focuses on searching for more convenient and environmentally friendly packaging.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.3
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• pp.27-35
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• 2011

Design of Sensor nodes in Wireless Sensor Network(WSN) should be considered some properties as electricity consumption, transmission speed, range, etc., and also be needed the protection against various attacks (e.g., eavesdropping, hacking, leakage of customer's secret data, and denial of services). The stream cipher Rabbit, selected for the final eSTREAM portfolio organized by EU ECRYPT and selected as algorithm in part of ISO/IEC 18033-4 Stream Ciphers on ISO Security Standardization recently, is a high speed stream cipher suitable for WSN. Since the stream cipher Rabbit was evaluated the complexity of side-channel analysis attack as 'Medium' in a theoretical approach, thus the method of power analysis attack to the stream cipher Rabbit and the verification of our method by practical experiments were described in this paper. We implemented the stream cipher Rabbit without countermeasures of power analysis attack on IEEE 802.15.4/ZigBee board with 8-bit RISC AVR microprocessor ATmega128L chip, and performed the experiments of power analysis based on difference of means and template using a Hamming weight model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1500-1506
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• 2020

In this paper, we study a scheduling problem based on reinforcement learning for overlay device-to-device (D2D) communication networks. Even though various technologies for D2D communication networks using Q-learning, which is one of reinforcement learning models, have been studied, Q-learning causes a tremendous complexity as the number of states and actions increases. In order to solve this problem, D2D communication technologies based on Deep Q Network (DQN) have been studied. In this paper, we thus design a DQN model by considering the characteristics of wireless communication systems, and propose a distributed scheduling scheme based on the DQN model that can reduce feedback and signaling overhead. The proposed model trains all parameters in a centralized manner, and transfers the final trained parameters to all mobiles. All mobiles individually determine their actions by using the transferred parameters. We analyze the performance of the proposed scheme by computer simulation and compare it with optimal scheme, opportunistic selection scheme and full transmission scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.809-817
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• 2020

In the design and development process of Small-Sat power distribution and transmission module, the stability of dynamic resources was evaluated by a deep learning algorithm. The requirements for the stability evaluation consisted of the power distribution function of the power distribution module and demand module to the SAR radar in Small-Sat. To verify the performance of the switching power components constituting the power module PDM, the reliability was verified using a dynamic neural network. The adoption material of deep learning for reliability verification is the power distribution function of the payload to the power supplied from the small satellite main body. Modeling targets for verifying the performance of this function are output voltage (slew rate control), voltage error, and load power characteristics. First, to this end, the Coefficient Structure area was defined by modeling, and PCB modules were fabricated to compare stability and reliability. Second, Levenberg-Marquare based Two-Way NARX neural network Sigmoid Transfer was used as a deep learning algorithm.