• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.318-321
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• 2017

Most of wearable platforms(i. e. Samsung Gear, Android Wear) are using most of Tizen mobile platform features without any changes. However wearable devices have unique characteristics due to wearable type, small battery, screen shape, poor network and relative short but frequent user interfaces. In general, a wearable device has a process to be paired with the mobile device, which includes capability exchange that includes information such as device model name, network capability (3G, LTE, Wi-Fi and so on), manufacturer and supported languages. In other word, a wearable device depends heavily on the companion device (i. e. phone, tablet), so wearable platform should consider this. In this paper, we provide the effective application management mechanism using these characteristics of wearable platform to enhance user experience and to reduce sluggish of wearable platform.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.672-674
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• 2014

Mobile communication technology was one of the GPS technology, SmartPhone, Tablet PC is equipped with a GPS. So the user has a navigation, speed and his position to send and receive a variety of information. Therefore, in this paper, Mobile devices, GPS, Wi-Fi and mobile networks, and the communication module uses algorithms to analysis of acceleration and output, the user is currently using the system to find out the kind of transportation. This is the users who are using a particular transport unnecessary information and apply it to different areas do not think I will be able to.

• Journal of Practical Engineering Education
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• v.13 no.2
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• pp.321-326
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• 2021

Wireless communication is a core technology constituting the Internet of Things (IoT), but there is no suitable educational equipment to learn various wireless communication technologies used in the Internet of Things through practice. This paper deals with the development of advanced education and training equipment that can perform various IoT wireless communication practices. It uses an Arduino mega board as a device to control various sensors. As wireless network technologies to send and receive the sensing date wirelessly, it makes use of RFID/NFC and Bluetooth among WPAN technologies, WiFi among WLAN technologies and LoRa and 2.4GHz wireless transceiver among WWAN technologies. In addition, GPS, infrared communication, I2C communication, and SPI communication are organized so that various IoT wireless communication technologies can be learned through practice. In addition, since the educational equipment developed in this paper is equipped with two devices, it is designed to perform transmission and reception experiments for wireless network technology within the equipment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.313-316
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• 2021

In the IoT(IoT: Internet of Things) environment, network configuration is essential to collect data generated from objects. Various communication methods are used to process data of objects, and wireless communication methods such as Bluetooth and WiFi are mainly used. In order to collect data of objects, a communication module must be installed to collect data generated from sensors or edge devices in real time. And in order to deliver data to the database, a software architecture must be configured. Data generated from objects can be stored and managed in a database in real time, and data necessary for industrial safety can be extracted and utilized for industrial safety service applications. In this paper, a network environment was constructed using a LoRa(LoRa: Long Range) gateway to collect object data, and a client/server data collection model was designed to collect object data transmitted from the LoRa module. In order to secure the resources necessary for data collection and storage management without data leakage, data collection should be possible in real time. As an application service, location data required for industrial safety can be stored and managed in a database in real time.

• Journal of Satellite, Information and Communications
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• v.12 no.1
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• pp.43-48
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• 2017

Recently, demands on civilian UAV (Unmanned Aerial Vehicle) has been increasing and appropriate communication system is required for the UAV. In this paper, the performance of the UAV communication system using commercial wireless mobile network is discussed. The main service area of the wireless mobile network is ground level however the flying range of the UAV is normally in high altitude. Because of this mismatch of service area the performance of the UAV communication system is degraded in high altitude. To compensate performance degradation of the UAV communications system in high altitude, adaptive array antenna is introduced which is able to overcome altitude limitation of the UAV communication system.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1381-1384
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• 2005

빠른 속도로 확산되고 있는 모바일 기기는 카메라, GPS, RFID 등과 같은 다양한 센서를 장착하고 Wi-Fi, WiMAX, WiBro 등의 무선 네트워크를 지원하는 형태로 발전하고 있다. 이러한 발전으로 사용자는 언제 어디서나 주변의 컴퓨팅 자원을 이용할 수 있게 되었고 모바일 기기의 서비스는 주변의 센서 또는 임베디드 컴퓨팅 장치로부터 수집되는 다양한 주변 환경 정보와 시스템 상태정보, 네트워크 상황정보 등의 디지털 정보를 이용하여 주변상황인식(context awareness)이 가능한 스마트 서비스로 발전하고 있다. 주변상황인식을 위하여 서비스는 주변에 존재하는 다양한 장치를 효율적으로 검색하고 이질적인(Heterogeneous) 장치와 정보의 표현 및 전송에 대한 호환성이 필요하다. 이러한 문제는 규격화된 프레임워크의 사용으로 해결할 수 있으며 상황정보의 관리 기능을 추가하여 서비스 개발의 생산성을 높일 수 있다 본 논문에서는 모바일 컴퓨팅 환경에서 상황정보의 제공과 사용에 적합한 프레임워크로서 MoCE(Mobile Context Exploerer) 아키텍처를 설계하였다. MoCE 는 상황정보의 수집, 변환, 분류, 통합 등의 기능을 제공하고 모바일 환경의 특성에 기인한 상황정보 발견 및 전송 프로토콜을 설계하여 사용하고 있다. 또한 Surround multiCam 서비스 예제를 구현하여 제안한 아키텍처의 안정성 및 성능을 실험하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.740-746
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• 2013

Machine to machine (M2M) communication is a converged ICT(Information and Communications Technology) platform which can utilize communications services among people and things anytime, any place in realtime. The M2M platform consists of three components; M2M area networks sensing and generating data of things by various sensors and devices; public networks transporting those data; and M2M applications utilizing the aggregated data. There exist however two practical obstacles to realize the M2M communications in terms of interoperability between the WCDMA-based public network and the local networks based on W-Fi or ZigBee; one is the cost problem required to access the public network, and the other is the lack of a cost-effective modem or gateway to connect two different networks. In this paper, we proposed and implemented a novel M2M platform based on PWW (Person Area Network) which can resolve those two issues by using a proposed gateway connecting the local network and smartphones as application devices without access the WCDMA-based public network. We have shown that the proposed platform is very practical to adopt to the real environment by actual testing with the own developed smartphone applications.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.4
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• pp.93-99
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• 2011

This paper proposes a novel network jitter estimation algorithm for robust VoIP communication system. The proposed method computes the current network environment mode using the differences of arrival time and generation time from sequential received packets. According to the current network environment mode, the jitter variance weights is adjusted to minimize the error for estimating the network jitter. The jitter average and variance are calculated by the autoregressive estimated algorithm, and then the network jitter is estimated by applying the jitter variance weights.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.281-284
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• 2005

WPA is a security service that greatly increases data protection and access control on WLANs. WPA uses TKIP that is secure algorithm of 802.11i and 802.1X/EAP authentication. It provides enhanced secure ability with the dynamic security key to correct WEP's weaknesses. In this paper, we obtain measured data transmission time that by how to create secure key of WPA in the wired and wireless network. The result shows that the delay of data transmission time was not long even if used WPA.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.60-63
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• 2011

인터넷은 단순한 정보습득을 위한 공간을 넘어 사람들이 모여 교류하는 '소통의 장'으로서 역할을 하고 있다. 최근에는 타인과 끊임없이 대화를 나누고 소통하려는 인간의 기본 욕구를 반영한 서비스인 SNS(Social Network Service)가 전 세계의 주목을 받고 있다. 또한 LBS(Location-Based Service)는 GPS, Wi-Fi를 통한 위치정보를 활용하여 업무생산성 개선 및 다양한 생활 편의를 제공하는 서비스이다. 본 논문에서는 안드로이드 OS를 기반으로 LBS와 SNS를 통합한 어플리케이션을 제안한다. 개인용 모바일 정보기기인 스마트폰을 활용하여, 위치정보에 이용자 정보, SNS를 결합하여 서비스를 고도화 한다. 지인들의 위치를 기반으로 현재 상태, 트윗(Twit)을 통해 정보의 공유 및 활용을 극대화 할 수 있다. 이를 통해 사용자들이 적극적이고 용이하게 온라인 Identity를 표현하는 것을 목적으로 본 시스템을 제안한다.