• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.310-312
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• 2014

현재 대구시 소방관들은 소화전, 위험물들의 위치가 모바일 어플리케이션화 되어있지 않다. 이로 인해 관리 및 화재시 현장에 나갈 때 바로 검색할 수 없기 때문에 어려움을 겪고 있다. 본 논문에서는 소화전과 위험물의 모든 정보를 제공하는 모바일 어플리케이션을 통하여 언제 어디서나 소화전과 위험물의 위치와 정보에 접근할 수 있게 하였다. 이와 함께 현재 소방대원들이 사용하는 무전기외 간섭, 끊김, 차단등과 같은 문제점을 개선하기 위하여 기존의 무전기가 사용하던 주파수대역보다 안정되고 좋은 품질의 Wi-FI 통신망을 이용하여 높은 통화품질의 모바일 단말기 기반의 무전통신 서비스를 제공한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.601-604
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• 2014

GPS 난청지역인 실내 LBS(Location Based Service)의 수요가 증가하고 있으며, 신뢰할 수 있는 정확도를 가진 실내 측위 방법론이 요구되고 있다. 본 논문에서는 오프라인 매장의 진열 상품 정보를 나타내는 전자가격 표시기(ESL)의 신호정보를 이용한 위치 측위 방법 및 위치 기반 서비스를 제안한다. 기존의 실내 위치기반 서비스의 주요 측위매체였던 WiFi에 비하여 월등한 측위 매체의 개수를 기반으로 1m 내의 측위 오차를 가짐을 확인하였다.

• Journal of Information Processing Systems
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• v.16 no.3
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• pp.541-556
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• 2020

Wireless networks have become integral to society as they provide mobility and scalability advantages. However, their disadvantage is that they cannot control the media, which makes them vulnerable to various types of attacks. One example of such attacks is the evil twin access point (AP) attack, in which an authorized AP is impersonated by mimicking its service set identifier (SSID) and media access control (MAC) address. Evil twin APs are a major source of deception in wireless networks, facilitating message forgery and eavesdropping. Hence, it is necessary to detect them rapidly. To this end, numerous methods using clock skew have been proposed for evil twin AP detection. However, clock skew is difficult to calculate precisely because wireless networks are vulnerable to noise. This paper proposes an evil twin AP detection method that uses a multiple-feature-based machine learning classification algorithm. The features used in the proposed method are clock skew, channel, received signal strength, and duration. The results of experiments conducted indicate that the proposed method has an evil twin AP detection accuracy of 100% using the random forest algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.758-765
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• 2008

Wide-spread deployment of infrastructure WLANs has made Wi-Fi an integral part of today's Internet access technology. WLANs suffer from degraded system throughput and each node's throughput fluctuates significantly in the saturation regime. In this paper, we propose a link layer traffic control mechanism which controls the offered load of DCF system. It is shown that the link layer traffic controller can improve DCF system throughput and reduce nodes' throughput fluctuation with properly controlled offered load. We propose a dynamic traffic control algorithm which can find an optimal offered load and show its performance improvement with ns-2 simulation.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.457-465
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• 2019

This paper present developing methods of man-machine interface(MMI) system for smart temperature controller with android platform. This MMI system could communicate with mobile machine. Firstly we present electrical hardware design method of MMI system of smart temperature controller. Smart temperature controller is composed of dual processors. Secondly we develop operating software of MMI system using android development environment. And finally we present verification of MMI systems of smart temperature controller with android platform through field experiment. This MMI system with android platform has rapid development speed due to performance of android platform.

• Journal of the Korea Society of Computer and Information
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• v.17 no.2
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• pp.113-118
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• 2012

In this paper, we discuss the design of the Digital Down Converters for the IEEE 802.11 wireless LAN receiver, which can be used for the customized receiver. The customized receiver can be used for special puropsed services which cannot be realized using the general custom chip. In the OFDM receiver, DDC receives the up sampled Inphase/Quadrature signal from the AD converter and process down sampling and filtering procedures using the Cascaded Intergrator Filter and FIR filters. We discuss the structure and design methodology of DDC's and analyze the simulation results.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.632-637
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• 2017

Even though the potential for an accident in nuclear power plants is very low, multiple emergency plans are necessary because the impact of such an accident to the public is enormous. One of these emergency plans involves a robotic system for investigating accidents under conditions of high radiation and contaminated air. To develop a robot suitable for operation in a nuclear power plant, we focused on eliminating the three major obstacles that challenge robots in such conditions: the disconnection of radio communication, falling on uneven floors, and loss of localization. To solve the radio problem, a Wi-Fi extender was used in radio shadow areas. To reinforce the walking, we developed two- and four-leg convertible walking, a floor adaptive foot, a roly-poly defensive falling design, and automatic standing recovery after falling methods were developed. To allow the robot to determine its location in the containment building, a bar code landmark reading method was chosen. When a severe accident occurs, this robot will be useful for accident condition monitoring. We also anticipate the robot can serve as a workman aid in a high radiation area during normal operations.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.36-39
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• 2012

IT산업이 발전함에 따라 Bluetooth, ZigBee, RFID(Radio Frequency Identification)와 같은 근거리 무선통신 시스템에 대한 연구가 활발히 진행되고 있으며 다양한 분야에 활용되고 있다. 그 중 NFC(Near Field Communication)의 연구가 활발히 진행되고 있으며, NFC 태그와 함께 사용할 경우 활용성은 더욱 증대된다. 이와 관련하여 현재 다양한 NFC 태그관련 애플리케이션이 존재한다. 하지만 기존의 NFC 태그 애플리케이션은 단일 기능을 중심으로 제공하고, 여러 가지 기능을 이용하기 위해서는 여러 개의 NFC 태그가 필요하다는 단점이 있다. 이 점을 개선하고자 본 논문에서는 단일 NFC 태그로 다양한 기능을 제공하는 애플리케이션을 구현한다. 기능들로는 Text입력과 에어플레인 모드, Wi-Fi, Bluetooth, 무음모드, 알람, 알람설정, 사용자 지정 애플리케이션 선택 및 활성이 있다. 이러한 기능들은 사용자의 상황에 맞게 태그에 입력 시킬 수 있으며, 결과적으로 기존의 단일 기능을 제공하는 애플리케이션보다 개선됨 점을 나타낸다.

• Korean Journal of Artificial Intelligence
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• v.9 no.2
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• pp.23-28
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• 2021

In this paper, we studied a system that can efficiently build security management for single-person households using Arduino, ESP32-CAM and PIR sensors, and proposed an Android app with an internet connection. The ESP32-CAM is an Arduino compatible board that supports both Wi-Fi, Bluetooth, and cameras using an ESP32-based processor. The PCB on-board antenna may be used independently, and the sensitivity may be expanded by separately connecting the external antenna. This system has implemented an Arduino-based Unauthorized intrusion system that can significantly help prevent crimes in single-person households using the combination of PIR sensors, Arduino devices, and smartphones. unauthorized intrusion system, showing the connection between Arduino Uno and ESP32-CAM and with smartphone applications. Recently, if daily quarantine is underway around us and it is necessary to verify the identity of visitors, it is expected that it will help maintain a safety net if this system is applied for the purpose of facial recognition and restricting some access. This technology is widely used to verify that the characters in the two images entered into the system are the same or to determine who the characters in the images are most similar to among those previously stored in the internal database. There is an advantage that it may be implemented in a low-power, low-cost environment through image recognition, comparison, feature point extraction, and comparison.

• Clinical and Experimental Pediatrics
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• v.63 no.11
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• pp.422-428
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• 2020

In today's world, most children are exposed to various manmade electromagnetic fields (EMFs). EMFs are electromagnetic waves less than 300 GHz. A developing child's brain is vulnerable to electromagnetic radiation; thus, their caregivers' concerns about the health effects of EMFs are increasing. EMF exposure is divided into 2 categories: extremely low frequencies (ELFs; 3-3,000 Hz), involving high-voltage transmission lines and in-house wiring; and radiofrequencies (RFs; 30 kHz to 300 GHz), involving mobile phones, smart devices, base stations, WiFi, and 5G technologies. The biological effects of EMFs on humans include stimulation, thermal, and nonthermal, the latter of which is the least known. Among the various health issues related to EMFs, the most important issue is human carcinogenicity. According to the International Agency for Research on Cancer's (IARC's) evaluation of carcinogenic risks to humans, ELFs and RFs were evaluated as possible human carcinogens (Group 2B). However, the World Health Organization's (WHO's) view of EMFs remains undetermined. This article reviews the current knowledge of EMF exposure on humans, specifically children. EMF exposure sources, biological effects, current WHO and IARC opinions on carcinogenicity, and effects of EMF exposures on children will be discussed. As well-controlled EMF experiments in children are nearly impossible, scientific knowledge should be interpreted objectively. Precautionary approaches are recommended for children until the potential health effects of EMF are confirmed.