• Broadcasting and Media Magazine
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• v.7 no.1
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• pp.94-106
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• 2002

미국 지상파방송방식 ATSC의 전송방식(8-VSB)과 유럽지상파방송방식 DVB-T의 전송방식(COFDM)에 대한 현장비교시험이 서울을 비롯한 수도권 일원에서 2001년 9월 18일부터 2001년 11월 28일까지 약 3개월에 걸쳐 실시되었다. 이 시험에서는 도심지, 방사선, 원거리, 계층변조, 실내수신, 이동수신 등 6가지 유형에 대해 측정이 수행되었다. 측정결과, 유럽식이 미국식에 비해 모든 측정유형에서 우수한 성능을 보였다. 산악이 많고 도시에 건물이 밀집되어 다중경로간섭의 영향이 큰 한국의 환경에서는 유럽식이 더 적합한 방식임이 이 시험을 통해 입증되었고, 특히 이동수신의 경우 미국식은 거의 수신이 불가능한데 비해 유럽식은 표준화질에서 95%이상, 상당히 높은 고화질에서 70%이상의 수신율을 보여 미래의 새로운 서비스에 대한 적응성에서도 유럽식이 우수한 것으로 평가되었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1471-1477
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• 2019

Currently, there are various security methods in smart phone. Among them, pin number and pattern lock were used long as they were used from early smart phone. However, security is weak that much. The security of pin number is slightly high, but the security of conventional pattern lock remains moderate. However, the conventional pattern lock is still used by several people because of convenience. This is because some users' smart phones don't support biometric security. The most convenient security method for devices that don't support biometric security is pattern lock. However, this method is vulnerable to shoulder surfing attack and smudge attack. Therefore, we introduce random pattern lock that solves the vulnerability of the conventional pattern lock while maintaining the convenience of the pattern lock. This is a lock method that places each point placed on the screen in a circular shape and assigns a random number to it. Therefore, If this is introduced, It's expected to solve vulnerability.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.01a
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• pp.41-42
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• 2018

본 논문에서는 IoT 게이트웨이 기반 서비스 탐색 관련 상호운용성 지원을 공통 서비스 탐색 기법을 제안한다. 사물인터넷 분야에서는 다양한 서비스 탐색 기법이 제안되어 있다. 특히, 중앙 관리 방식과 분산 관리 방식으로 구분되어 제안되었다. 또한 네트워크 인터페이스 타입에 따라서 다른 프로토콜이 사용되고 있다. 이런 로컬 네트워크 내에 상이한 서비스 탐색 프로토콜의 사용을 서비스 탐색과 관련된 홍보기능이 제공되지 못하기 때문에 디바이스간 서비스 탐색이 이루어지지 못한다. 본 논문에서는 이런 문제점을 해결하기 위한 IoT 게이트웨이 내부에 서비스 디렉토리를 새롭게 정의하고 이를 이용하는 공통 서비스 탐색 방법을 제시한다.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.371-376
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• 2014

Consistently collecting a variety of vital signs is crucial in u-Healthcare. In order to do so, IoT is being considered as a top solution nowadays as an efficient network environment between the sensor and the server. This paper proposes a transmission method and compression algorithm which are appropriate for IoT environment. Results were compared to widely used compression methods, and were compared to other prior researches. The results showed that the compression ratio of our proposed algorithm was 11.7.

• Journal of Mushroom
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• v.11 no.4
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• pp.214-218
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• 2013

This study was carried out to find out suitable input method for air exchange about bottle cultivation of oyster mushroom. There was no difference of average temperature in cultivation room, but T1(direct introduction of outside air) was higher than T2(heat exchanger) and T3(air buffer) in the standard deviation. The ratio of cooling operating was the highest in August and in the descending order, T1 54%, T3 43%, T2 33%. At ratio of energy reduction, T2 and T3 were higher than T1. The operating ratio of heater was highest in January and in the descending order, T1 53%, T3 37%, T2 30%. At ratio of energy reduction(%), T2 and T3 were higher than T1 similar to result of cooling operating. Therefore there were largest in August about Cooling Degree-Hour and in January about Heating Degree-Hour. And fruitbody yields quality was excellent in T2 and T3 than T1. The suitable effective type of air exchange in oyster mushroom cultivation are heat exchange and air buffer system.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.173-179
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• 2017

Recently, with the development of IoT, there have been increasing cases of transmitting and receiving data by connecting more than one devices supporting various communication methods. In this paper, we propose a multi-terminal emulator supporting various communication methods. The system supports multiple channel connections for each communication method, schedules data transmission, collects communication statistics, represents them into graphs, and stores log records. By using this system, it is possible to test the communication connection between multiple devices, and it is expected to provide convenience for IoT system development.

• Convergence Security Journal
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• v.21 no.1
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• pp.9-17
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• 2021

Numerous IoT devices are connected to a wireless network environment to collect and transmit data without time and space limitations, but many security vulnerabilities are exposed in these process. But IoT security is not easy to create feasible security standards and device authentication due to differences in the approach or implementation of devices and networks. However, it is clear that the improvement and application of the standard framework for enhancing the security level of the device is the starting point to help the most successful security effect. In this study, we investigate the confidentiality, integrity, availability, and access control implementation plans for IoT devices (which are the basic goals of information security), and standardized security evaluation criteria for IoT devices, and study ways to improve them.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2178-2187
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• 2015

Bluetooth Low Energy (Bluetooth LE) is a representative break-through communication technology for wireless personal area networks on nowaday. In this environment, most of significant performance should be aiming to energy efficiency due to the policy for manufacturing light-weighted communication devices derived from requirement of world IoT market, and many researches have been developed to satisfy this requirement. While Bluetooth LE has been leading the low power communication technology required from the current market by employing duty cycle and frequency hopping approaches, it couldn't address the problem of reliability on broadcast transmissions. The main goal of this paper is aiming to addressing this problem by suggesting a new method. Furthermore analytic evaluations would also be proceeded to find objective results in the view point of broadcast transmission efficiency from Master device.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.430-435
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• 2018

In this paper, an improved decoding scheme for low-complexity parity-check(LCPC) code with small code length is proposed. The LCPC code is less complex than the turbo code or low density parity check(LDPC) code and requires less memory, making it suitable for communication between internet-of-things(IoT) devices. The IoT devices are required to have low complexity due to limited energy and have a low end-to-end delay time. In addition, since the packet length to be transmitted is small and the signal processing capability of the IoT terminal is small, the LCPC coding system should be as simple as possible. The LCPC code can correct all single errors and correct some of the two errors. In this paper, the proposed decoding scheme improves the bit error rate(BER) performance without increasing the complexity by correcting both errors using the soft value of the modulator output stage. As a result of the simulation using the proposed decoding scheme, the code gain of about 1.1 [dB] was obtained at the bit error rate of $10^{-5}$ compared with the existing decoding method.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.231-236
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• 2018

Recently, a wide variety of IoT environment is being created due to the rapid development of information and communication technology. And accordingly in a variety of network structures, a countless number of attack techniques and new types of vulnerabilities are producing a social disturbance. In May of 2018, Talos Intelligence, the Cisco threat intelligence team has newly discovered 'VPN-Filter', which constitutes a large-scale IoT-based botnet, is infecting consumer routers in over 54 countries around the world. In this paper, types of IoT-based botnets and the attack techniques utilizing botnet will be examined and the countermeasure technique through EXIF metadata removal method which is the cause of connection method of C & C Server will be proposed by examining the characteristics of attack vulnerabilities and attack scenarios of VPN-Filter.