• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.107-115
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• 2013

Smart appliances with multi-media and telecommunication equipments provide users complicated convenience functions. On the contrary, 8-bit controller-based low performance electronics still cannot afford such multimedia and telecommunication. If we find a way to have low-end electronics connected and provide complicated functions, they can be also made "smart". Fortunately, 8-bit controllers used in low-end appliances have UART, which can be connected to any of BlueTooth, Wi-Fi and ZigBee communication modules which can, in turn, communicate with smart devices. Any communication module can be attached to the low-end electronics due to the variety of smart devices' connectivity at the other side. Although the convenience functions seem complicated, they are actually macros in a script form composed of micro commands which implement the base functions of appliances. Since the kinds of the base functions are not that many, the low-end electronic appliances will become "smart" if their control program can be extended to execute sequentially the micro commands in any combination. Such simple innovation has not seen the world, until now due to the overhead of the additionally required hardware such as display devices and buttons. The high-quality display and touch screen functionalities of smart devices can replace the required hardware, and remove the overhead completely. In fact, the low-end appliances become smart as if an "evolution kit" is newly equipped.

• Convergence Security Journal
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• v.12 no.1
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• pp.55-61
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• 2012

Owing to the development of wireless infrastructure and mobile communication technology, There is growing interest in smart phone using it. The resulting popularity of smart phone has increased the Mobile Malicious AP-related security threat and the access to the wireless AP(Access Point) using Wi-Fi. mobile AP mechanism is the use of a mobile device with Internet access such as 3G cellular service to serve as an Internet gateway or access point for other devices. Within the enterprise, the use of mobile AP mechanism made corporate information management difficult owing to use wireless system that is impossible to wire packet monitoring. In this thesis, we propose mobile AP mechanism-based mobile malicious AP detection and prevention mechanism in radius authentication server network. Detection approach detects mobile AP mechanism-based mobile malicious AP by sniffing the beacon frame and analyzing the difference between an authorized AP and a mobile AP mechanism-based mobile malicious AP detection.

• Journal of Communications and Networks
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• v.18 no.5
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• pp.837-845
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• 2016

Providing a customer with tailored location-based services (LBSs) is a fundamental problem. For location-estimation techniques with radio-based measurements, LBS applications are widely available for mobile devices (MDs), such as smartphones, enabling users to run multi-task applications. LBS information not only enables obtaining the current location of an MD but also provides real-time push-pull communication service. For indoor environments, localization technologies based on radio frequency (RF) pattern-matching approaches are accurate and commonly used. However, to survey radio information for pattern-matching approaches, a considerable amount of time and work is spent in indoor environments. Consequently, in order to reduce the system-deployment cost and computing complexity, this article proposes an indoor positioning approach, which involves using Asus Xtion to facilitate capturing RF signals during an offline site survey. The depth information obtained using Asus Xtion is utilized to estimate the locations and predict the received signal strength (RF information) at uncertain locations. The proposed approach effectively reduces not only the time and work costs but also the computing complexity involved in determining the orientation and RF during the online positioning phase by estimating the user's location by using a smartphone. The experimental results demonstrated that more than 78% of time was saved, and the number of samples acquired using the proposed method during the offline phase was twice as much as that acquired using the conventional method. For the online phase, the location estimates have error distances of less than 2.67 m. Therefore, the proposed approach is beneficial for use in various LBS applications.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.124-137
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• 2018

The OTT service in Korea is not as popular as that in the U. S. This study argues that one of the major reasons of poor performance of OTT in Korea is that the OTT service providers did not acquire attracting contents, thus failing to appeal to Korean users. The other reason is Korean users are not willing to use OTT services because of high telecommunications fees to use OTT services. That is why most OTT users are using OTT services in WiFi zones, such as house, workplace, or school. This study investigated the popular OTT contents in recent three years, and how these popular OTT contents are provided in OTT service platforms, and how these contents are used in different places. The results of this study may provide several implications for OTT service providers' strategies in the future, and propose policy implications for the development of OTT services in Korea.

• International journal of advanced smart convergence
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• v.6 no.1
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• pp.82-88
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• 2017

Emergency lights and exit signs are an indispensable part of safety precautions for effective evacuation in case of emergency in public buildings. These emergency sign indicates safe escape routes and emergency doors, using an internationally recognizable sign. However visibility of those signs drops drastically in case of emergency situations like fire smoke, etc. and loss of visibility causes serious problems for safety evacuation. This paper propose a novel emergency light and exit sign built-in with Bluetooth Low Energy (BLE) Beacon to assist the emergency self-guiding evacuation using devices for crisis and emergency management to avoid panic condition inside the buildings. In this approach, the emergency light and exit sign with the BLE beacons deployed in the indoor environments and the smart devices detect their indoor positions, direction to move, and next exit sign position from beacon messages and interact with map server in the Internet / Intranet over the available LTE and/or Wi-Fi network connectivity. The map server generate an optimal emergency exit path according to the nearest emergency exit based on a novel graph generation method for less route computation for each smart device. All emergency exit path data interfaces among three system components, the emergency exit signs, map server, and smart devices, have been defined for modular implementation of our emergency evacuation system. The proposed exit sign experimental system has been deployed and evaluated in real-time building environment thoroughly and gives a good evidence that the modular design of the proposed exit sign system and a novel approach to compute emergency exit path route based on the BLE beacon message, map server, and smart devices is competitive and viable.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.953-958
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• 2015

Raspberry Pi is a credit card-sized computer with support for a large number of input and output peripherals. This makes it the perfect platform for interaction with many different devices and for usage in a wide range of applications. When combined with Wi-Fi, it can communicate remotely, therefore increasing its suitability for the construction of wireless sensor nodes. In addition, data processing and decision-making can be based on artificial intelligence, what is performed in developed testbed on the example of monitoring and determining the confidence of fire. In this paper, we demonstrated the usage of Raspberry Pi as a sensor web node for fire-safety monitoring in a building. When the UV-flame sensors detect a flame as thin as that of a candle, the Raspberry Pi sends a push-message to notify the assigned smartphone of the on-site situation through the GCM server. A mobile app was developed to provide a real-time video streaming service in order to determine a false alarm. If an emergency occurs, one can immediately call for help.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.723-731
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• 2005

Wide spread deployment of infrastructure WLANs has made Wi Fi an integral part of today's Internet access technology. Despite its crucial role in affecting end to end performance, past research has focused on MAC protocol enhancement, analysis and simulation based performance evaluation without sufficient consideration for modeling inaccuracies stemming from inter layer dependencies, including physical layer diversity, that significantly impact performance. We take a fresh look at IEEE 802.11 WLANs, and using experiment, simulation, and analysis demonstrate its surprisingly agile performance traits. Contention based MAC throughput degrades gracefully under congested conditions, enabled by physical layer channel diversity that reduces the effective level of MAC contention. In contrast, fairness and jitter significantly degrade at a critical offered load. This duality obviates the need for link layer flow control for throughput improvement but necessitates traffic control for fairness and QoS. We use experimentation and simulation in a complementary fashion, pointing out performance characteristics where they agree and differ.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.909-922
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• 2012

To fully utilize scarce spectrum resource, it's necessary to develop and evaluate promising business models prior to making technology R&D plan and industrial promotion policy. The purpose of this paper is to design potential business models, evaluate the propriety of commercializing the models, and discuss promotion policies after exploring promising sectors consuming spectrum resources. The research is based on TV white space, which is vacant TV channels in region or time domain and considered as core spectrum resource along with digital terrestrial television switchover. As the result, four kinds of business models were derived, including broadcasting and telecommunication types. Each model was discussed from four standpoints: customer value proposition, profit formula, key resources, and key processes, and the propriety for commercialization was evaluated by three dimensions: technological evaluations, business-oriented evaluations, and user-oriented evaluations. The promotion policies of government and market participants for the activation of TV White space-based business models were discussed as well.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.835-838
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• 2013

국토해양부에서는 전국 도로표지의 효율적인 관리를 위해 국내 300여개 도로표지 관리기관에서 도로표지업무에 활용할 수 있도록 2001년 웹 기반의 도로표지전산관리시스템을 구축하였고, 2003년 도로표지종합관리센터를 설립하여 지속적으로 운영해오고 있다. 이는 네트워크 기반의 도로망도 상에서 전국 도로표지를 연계하여 관리할 수 있어 도로표지의 안내 연결성 확보 등 국내 도로표지 관리업무에 많은 부분 기여해 왔다. 최근 들어서는 모바일 환경이 구축되면서 인터넷이 연결된 사무공간 외에 현장에서도 시스템을 활용하고자 하는 요구가 증가하게 되었다. 따라서 도로표지종합관리센터에서는 도로표지전산관리시스템 이용자들의 편의를 증진하기 위하여 현장지원을 위한 도로표지 모바일 어플리케이션을 개발하였다. 모바일 어플리케이션은 스마트폰, 스마트패드 등 3G/4G/Wi-Fi 등 무선통신이 가능한 다양한 모바일 스마트 기기를 활용하여 도로표지전산관리시스템의 기능을 현장에서 활용할 수 있도록 하였으며, 현장이라는 공간 특성을 반영하여 쉽고 간단하게 기능을 구현하였다는 데 특징이 있다. 이를 통해 도로표지 담당자들은 언제 어디서든 도로표지 정보의 조회가 가능하고, 현장조사 시 표지 사진과 관련 정보를 수집하여 현장에서 즉시 도로표지전산관리시스템에 표지정보를 입력하거나 수정 할 수 있다. 현재는 모바일 어플리케이션 버전 1.0이 개발된 상태이며, 향후 다양하고 반복적인 사용자 활용 패턴을 면밀히 분석하여 보다 사용하기 쉽게 도로표지전산관리시스템 기능을 사무공간에서와 같이 모바일 어플리케이션도 사용할 수 있도록 지속적으로 개선해 나가고자 한다.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.6
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• pp.197-208
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• 2023

In the coming future, anyone using the Internet will have more than one NFT. Unlike FT, NFT can specify the owner, and tracking management is easier than FT. Even in the 2022 survey, WPA2 is the most widely used wireless protocol worldwide to date. As it is a protocol that came out in 2006, it is a protocol with various vulnerabilities at this time. In order to use WPA2-EAP or WPA3 (2018), which were released to compensate for the vulnerabilities of WPA2, additional equipment upgrades are required for STA (station) and AP (access point, router), which are connected devices. The use of expensive router equipment solves the security part, but it is economically inefficient to be introduced in Small Office Home Office (SOHO). This paper uses NFT as a means of authentication and uses the existing WPA2 as it is without equipment upgrade, defend crack tools of WPA2 that have been widely used so far and compared to the existing WPA2, it was shown that it was not difficult to actually use them in SOHO.