• Journal of the Korea Society of Computer and Information
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• v.22 no.3
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• pp.35-43
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• 2017

In IoT(Internet of Things) environment, users want to receive customized service by users' personal device such as smart watch and pendant. To fulfill this requirement, the mobile device should support a lot of functions. However, the miniaturization of mobile devices is another requirement and has limitation such as tiny display. limited I/O, and less powerful processors. To solve this limitation problem and provide customized service to users, this paper proposes a collaboration system for sharing various computing resources. The paper also proposes the method for reasoning and recommending suitable resources to compose the user-requested service in small device with limited power on expected time. For this goal, our system adopts MBTI(Myers-Briggs Type Indicator) to analyzes user's behavior pattern and recommends personalized resources based on the result of the analyzation. The evaluation in this paper shows that our approach not only reduces recommendation time but also increases user satisfaction with the result of recommendation.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.3
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• pp.151-156
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• 2015

Recently, an embedded flash memory has been widely used for the Internet of Things(IoT). Due to its nonvolatility, economical feasibility, stability, low power usage, and fast speed. With respect to power consumption, the embedded memory system must consider the most significant design factor. The objective of this research is to design high performance and low power NAND flash memory architecture including a dual buffer as a replacement for NOR flash. Simulation shows that the proposed NAND flash system can achieve better performance than a conventional NOR flash memory. Furthermore, the average memory access time of the proposed system is better that of other buffer systems with three times more space. The use of a small buffer results in a significant reduction in power consumption.

• Journal of electromagnetic engineering and science
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• v.14 no.3
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• pp.317-319
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• 2014

In this letter, a small-loop antenna for a mobile UHF RFID device is proposed. To achieve size reduction, a ferrite sheet optimized for a 900 MHz band is applied. The overall dimensions of the antenna are $46mm{\times}35mm{\times}0.24mm$, and it has a bandwidth of 45 MHz with a return loss of less than -6 dB. The proposed antenna satisfies near and far field UHF EPC global frequency band communications (902-928 MHz).

• Journal of Korea Multimedia Society
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• v.24 no.1
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• pp.67-74
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• 2021

As IoT(Internet Of Things) devices like a smart sensor have constrained power sources, a power strategy is critical in WSN(Wireless Sensor Networks). Therefore, it is necessary to figure out the residual power of each sensor node for managing power strategies in WSN, which, however, requires additional data transmission, leading to more power consumption. In this paper, a residual power estimation method was proposed, which uses ignorantly small amount of power consumption in the resource-constrained wireless networks including WSN. A residual power prediction is possible with the least data transmission by using Machine Learning method with some training data in this proposal. The performance of the proposed scheme was evaluated by machine learning method, simulation, and analysis.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.69-70
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• 2017

국내외에서 CCTV, IoT(Internet of Things)를 활용한 재난 재해 감지 기술이 활발히 연구되고 활용되고 있다. 그러나 재난 감지 시스템은 전기와 같은 기반 시설이 구축되어야 활용이 가능하기에 지역적으로 시스템 구축에 어려움이 있는 재난 취약 지역(Disaster Vulnerability area)이 발생하게 된다. 이를 해결하기 위한 방안으로 소형 자가발전시스템을 구축하여 CCTV를 활용한 실시간 재난 감시 방안을 마련하고자 하며, 이에 일환으로 울산시 기상관측 자료와 소형 자가발전시스템 발전량간의 상관관계를 분석하여 기후 요소가 발전량에 미치는 영향을 살펴보고 추가적인 연구 방향에 대해 논의하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.679-680
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• 2018

IoT(Internet of Things) is no longer just a concept, and It has become common as individual users have tried to implement it directly through small boards and components. This research implemented a system to control a general toy car using Raspberry pi and motor driver. This research will help develop ordinary toy cars to RC cars or learn on their own and drive on their own through further development.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.128-130
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• 2017

본 논문에서는 IoST(Internet of Small Things)로 분류되는 소형화된 사물에 적합하도록 기존 2핀을 사용하여 통신하는 I2C 직렬 통신과 달리 단일 핀을 사용하여 온도 습도 통신이 가능한 통신 기술을 연구하였다. 기존의 센서 정보를 주고받는 I2C 직렬 통신 방식은 클럭과 데이터 핀을 사용하여 비교적 빠른 속도로 데이터 전송을 하지만 단일 핀 사용 방식보다 전력소모에 큰 영향을 주기 때문에 IoST 통신에서 보다 적합하도록 하드웨어 설계를 단순화하여 면적을 줄이고 전력 소모를 줄이도록 하는 방안을 연구하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.242-244
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• 2019

본 논문에서는 공장에너지관리를 위한 IoT 기반 플랫폼 개발에 대한 연구를 다루고 있다. 특히, 스마트팩토리에 대한 고사양성 서비스를 제공하는 것이 아닌, 소규모 공장에서도 적용할 수 있는 시스템을 통해 스마트팩토리로 전향하기 위한 기반을 제공하고자 한다. 본 시스템은 IoT 표준을 기반으로 하고 있으며, 클라우드 서비스와 분석시스템 등을 제공한다.

• ETRI Journal
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• v.42 no.6
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• pp.951-964
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• 2020

This paper presents a lightweight true random number generator (TRNG) using beta radiation that is useful for Internet of Things (IoT) security. In general, a random number generator (RNG) is required for all secure communication devices because random numbers are needed to generate encryption keys. Most RNGs are computer algorithms and use physical noise as their seed. However, it is difficult to obtain physical noise in small IoT devices. Since IoT security functions are required in almost all countries, IoT devices must be equipped with security algorithms that can pass the cryptographic module validation programs of each country. In this regard, it is very cumbersome to embed security algorithms, random number generation algorithms, and even physical noise sources in small IoT devices. Therefore, this paper introduces a lightweight TRNG comprising a thin-film beta-radiation source and integrated circuits (ICs). Although the ICs are currently being designed, the IC design was functionally verified at the board level. Our random numbers are output from a verification board and tested according to National Institute of Standards and Technology standards.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.2002-2019
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• 2017

RPL routing protocol for low-power and lossy networks is an Internet Engineering Task Force (IETF) recommended IPv6 based protocol for routing over Low power Lossy Networks (LLNs). RPL is proposed for networks with characteristics like small packet size, low bandwidth, low data rate, lossy wireless links and low power. RPL is a proactive routing protocol that creates a Directed Acyclic Graph (DAG) of the network topology. RPL is increasingly used for Internet of Things (IoT) which comprises of heterogeneous networks and applications. RPL proposes a single path routing strategy. The forwarding technique of RPL does not support multiple paths between source and destination. Multipath routing is an important strategy used in both sensor and ad-hoc network for performance enhancement. Multipath routing is also used to achieve multi-fold objectives including higher reliability, increase in throughput, fault tolerance, congestion mitigation and hole avoidance. In this paper, M-RPL (Multi-path extension of RPL) is proposed, which aims to provide temporary multiple paths during congestion over a single routing path. Congestion is primarily detected using buffer size and packet delivery ratio at forwarding nodes. Congestion is mitigated by creating partially disjoint multiple paths and by avoiding forwarding of packets through the congested node. Detailed simulation analysis of M-RPL against RPL in both grid and random topologies shows that M-RPL successfully mitigates congestion and it enhances overall network throughput.