• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1110-1116
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• 2021

In this paper, we propose a conformal Ku-band data link antenna to ensure low RCS of stealth UAV. As a phased array antenna with electrical beam steering function, a transmitter and a receiver were designed and manufactured for FDD communication, respectively. Each antenna is designed as a 12*12 planar array antenna and has a function to form a uni-directional pattern and a bi-directional pattern through phase control of unit elements. The beam steering range is designed to be able to steer up to 60 degrees in theta direction and 360 degrees in the phi direction. As a result of manufacturing and measurement, the conformal type radome has low transmission loss and meets the required specifications including system performance. The feasibility of mounting the stealth UAV has been confirmed, and future research directions such as interworking of baseband devices and conversion to digital beam steering function are suggested.

• Convergence Security Journal
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• v.6 no.3
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• pp.37-47
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• 2006

In this research, We connect the terrestrial magnetism sensor of the Philips to a bluetooth communication system and measured 360 degree of the azimuth change the angle with an incline of 5 degrees to an order direction. The value of the azimuth to be measured sent to the Bluetooth communication system and analyzed the measuring value in the 100m as moved. Using the bluetooth, we could send the measuring value of the azimuth without the bearing error in the plain without an electric wave obstacle within a distance in straight line 100M. We got the value of the azimuth have 98% reliability to maintain at a level with the terrestrial magnetism sensor. Based on this research. We send the measuring value of the azimuth which the accuracy is improved to a mobile intelligent robot moving a land inclined equipped with this system and can track the azimuth of it.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1364-1370
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• 2019

Tilt sensors are mainly used to measure the collapse of structures such as buildings, bridges and tunnels. Recently, due to the ease of use and low price, many tilt sensors using MEMS sensors have been used, but the measurement angle range is limited, and thus, they do not have high precision for 360 degree. This is due to the inherent offset and scale errors of MEMS sensors. In this paper, we proposed an algorithm for the calculation of precision angles to reduce the mechanical error of MEMS sensors, and produced a MEMS sensor module and a transmission module to compare the angle accuracy of sensor modules before calibration and the angle measurement accuracy after calibration. Experimental results show that the proposed technique has a precision of ± 0.015 degrees for all 360-degree.

• Journal of Convergence for Information Technology
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• v.7 no.2
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• pp.53-58
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• 2017

This paper describes the design of a simulator for analyzing the accuracy of a correlative interferometer(CI) direction finder. CI direction finder is robust to noise, so it is often used in aircraft or ships where complex antenna installation is required, and the direction finding accuracy is very high. When the radio wave is incident at a specific azimuth angle, the phase difference calculated in a noiseless environment and the phase difference measured in a real environment with noise are fused to estimate the largest correlation coefficient as the azimuth angle of the radio wave. The simulator receives RF frequency, the number of antennas, the antenna coordinates, the transmission signal intensity, the bandwidth of the receiver, the gain and the payload effect, and calculates the direction finding accuracy of 0-360 degrees azimuth and 0-60 degree elevation with 0.5 degree. accuracy.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.85-91
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• 2009

Because ubiquitous environment has come with growing IT technology, Researches wireless sensor network are actively on going in many aspects. In this paper, we proposed simple method of distance measurement for omnidirectional distance calculation in wireless sensor network. In addition, we design and implement the proposed method. Then, we verify it through experiments at real environments. when we use the proposed method, maximum distance of measurement is decreased, but we measure distance from degrees. In this paper, we show drop rate and accuracy rate of ultrasonic distance estimation with and without omnidirectional device through experiments at real environments.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.217-228
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• 2024

LiDAR(Light Detection And Ranging) sensors, which play a pivotal role among cameras, RADAR(RAdio Detection And Ranging), and ultrasonic sensors for the safe operation of autonomous vehicles, can recognize and detect objects in 360 degrees. However, since LiDAR sensors use lasers to measure distance, they are vulnerable to attackers and face various security threats. In this paper, we examine several security threats against LiDAR sensors: relay, spoofing, and replay attacks, analyze the possibility and impact of physical jamming attacks, and analyze the risk these attacks pose to the reliability of autonomous driving systems. Through experiments, we show that jamming attacks can cause errors in the ranging ability of LiDAR sensors. With vehicle-to-vehicle (V2V) communication, multi-sensor fusion under development and LiDAR anomaly data detection, this work aims to provide a basic direction for countermeasures against these threats enhancing the security of autonomous vehicles, and verify the practical applicability and effectiveness of the proposed countermeasures in future research.

• Asia Marketing Journal
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• v.11 no.3
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• pp.185-203
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• 2009

Yuhan Kimberly, a joint-venture company of Korean Yuhan Company and American Kimberly-Clark, opened a premium diaper market in Korea by launching Pull-Ups which was pants-typed diapers in 1993. Pull-Ups was imported as finished goods from Kimberly-Clark. However, in spite of its huge market share in United States, it failed to land down in Korean market because of wrong positioning strategy which did not consider domestic customers' tastes. In 1996, Yuhan-Kimberly brought out a pants-typed diaper, Huggies-Toddler, to Korean market again. This paved the way for the combination of Kimberly-Clark's production power and Yuhan-Kimberly's marketing power and led to launch new product superior to Pull-Ups. However, this product was unsuccessful in the market because of wrong positioning which did not catch domestic customer's life styles such as cultural, environmental and habitual differences in toilet training, the cost increase coming from IMF crisis in Korea, weak trust within the company, weak trust within the company, and too much higher price than regular diapers. In 2005, Yuhan-Kimberly redeveloped new pants market business strategy. It was organically combined with winning product development plan, winning communication strategy and the market structure change through the pants market creation. Customer's habit, usage and attitude were studied with total 55 times market investigations. Also, all processes from planning to designing were executed in the customer's view by investigating product research, positioning research and advertisement research. Yuhan-Kimberly repositioned new product as a wearing diaper not as a toilet training diaper and launched Huggies Magic Panty as a premium product which had 25% higher price than previous Huggies. Huggies Magic Panty was recognized as a great hit product in domestic diaper market and the sales recorded 37.6 bill won in 2006, 57.2 bill won in 2007, and 90 bill won in 2008 since launching in 2005. The reason of Huggies Magic Panty's success was the repositioning strategy deduced from the precise check of customer's usage habit. It was the winning strategy of Huggies that were market investigation in order to survive in domestic baby goods market where a lot of companies struggled intensively, the exact positioning based on its market investigation and aggressive 360 degree communication strategy to give customers impressions efficiently.