• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.401-403
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• 2015

This paper describes an efficient hardware design of 128-bit block cipher algorithm LEA(lightweight encryption algorithm). In order to achieve area-efficient and low-power implementation, round block and key scheduler block are optimized to share hardware resources for encryption and decryption. The key scheduler register is modified to reduce clock cycles required for key scheduling, which results in improved encryption/decryption performance. FPGA synthesis results of the LEA processor show that it has 2,364 slices, and the estimated performance for the master key of 128/192/256-bit at 113 MHz clock frequency is about 181/162/109 Mbps, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.6
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• pp.910-915
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• 2018

The precise time, which is an essential element of the Global Navigation Satellite System (GNSS), such as US GPS, GLONASS in Russia, Galileo in Europe, and Beidou in China, is an important foundation for various economic activities around the world. Communication systems, power grids, IoT, Cloud computing and financial networks operate based on the precise time not only for the operating principles, but also for the synchronization and operational efficiency between tasks. In this paper, we introduce the Atomium software for the first time in South Korea. Atomium was developed by ORB in Belgium to calculate the clock error(clock solution) with GNSS signal observation data based on PPP method. The observation data is provided by Korea Research Institute of Standards and Science(KRISS). The results of MJD57106 with Atomium software are presented.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.5
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• pp.107-112
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• 2020

Ultra-lightweight password CHAM is an algorithm with efficient addition, rotation and XOR operations on resource constrained devices. CHAM shows high computational performance, especially on IoT platforms. However, lightweight block encryption algorithms used on the Internet of Things may be vulnerable to side channel analysis. In this paper, we demonstrate the vulnerability to side channel attack by attempting a first power analysis attack against CHAM. In addition, a safe algorithm was proposed and implemented by applying a masking technique to safely defend the attack. This implementation implements an efficient and secure CHAM block cipher using the instruction set of an 8-bit AVR processor.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2546-2553
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• 2015

Falling can happen to anyone, anywhere at anytime and especially it is one of the risk factor that can lead causes of death of persons aged 65 and over. Recently, the study of fall detection mechanisms as a smart healthcare service based on the IoT(Internet of Things) are being actively investigated. In this paper, we implement a fall detection system using arduino as a smart sensor communicates with a smart device. When transmitting the information of the acceleration on a sensor smart sensor with a BLE(Bluetooth Low Energy), the smart device processing and analyzing this information. and determines a fall situation. A fall detection system based on the Internet of Things which using smart sensor and smart device, has the advantage of being able to overcome the mobility and portability constraints.

• Annual Conference of KIPS
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• 2019.05a
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• pp.458-460
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• 2019

최근 클라우드 시스템 환경이 점차 늘어남에 따라 데이터 센터(IDC) 구축이 점차 늘어나가고 있다. 데이터 센터는 최근 부각하고 있는 4 차 산업 영역에서 사물 인터넷(IoT), 자율주행차 등 에서 처리될 대용량 데이터로 인한 이를 처리하는 중요한 역할을 담당하고 있다. 데이터센터 운영에는 대량의 에너지가 필요하다. 수 많은 컴퓨터에서 발생하는 열에너지를 처리하기 위하여 대량의 전력 냉방 에너지를 소비하고 있다. 냉방 공조 운영은 데이터 센터 운영에 중요한 역할을 한다. 이유는 많은 컴퓨터를 가동하는 비용보다 부대 시설로 운영되는 냉방 에너지를 보다 많이 소비하는 현상까지 발생하고 있다. 이에 최근 데이터 센터 냉방 공조 운영을 효율화하는 것에 연구를 맞추고 있다. 본 논문에서는 냉방 공조 운영 효율화 하도록 하기 위해서 다중 기계 학습을 활용한 데이터 센터의 냉방 에너지 절감 시스템을 제안하고자 한다. 기존의 단수 알고리즘을 활용하여 머신 러닝의 모델구현 방식이 아닌 다중의 기계 학습을 통하여 최적화된 모델을 일일 배치로 생성하여 예측을 하는 시스템이다. 본 시스템을 통하여 사전에 최적화된 냉방 운영을 하여 기존 데이터 센터의 운영되는 과다 냉방을 감축 시켜 에너지를 절감해주는 기능을 제공한다. 본 논문 시스템 연구 결과는 폭발적으로 늘어가고 있는 데이터 센터의 에너지 효율화에 기여할 수 있고, 클라우드 사업에서 경쟁력을 줄 수 있는 운영 시스템 방안을 제시한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.513-515
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• 2022

Manufacturing data collected using IoT devices in a smart factory environment is generally reliable except for noises caused by external factors. However, unlike manufacturing data that is collected mechanically, process data manually recorded by field-workers can cause problems such as the misspelled entries or the missing entries. Therefore, process data must be validated before being used as training data for artificial intelligence models. In this paper, based on the fact that which is a linear relationship between the power consumption of the MCT machine and the production of the product recorded by the field-workers, we detect anomalous records of the workers using robust linear regression.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.63-72
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• 2018

Theoretical modelling and computational results for frequency coordination are presented based upon minimum coupling loss regarding the same or different wireless systems. Essential parameters involved in frequency coordination are discussed in view of system characteristics, propagation model, availability and protection ratio, frequency dependent rejection or adjacent channel interference ratio, discrimination angle, and its computational results are also evaluated. To illustrate frequency coordination procedure, received interference power between fixed wireless system of victim and mobile base station of interferer are analyzed in urban or sub-urban area and also compared with maximum allowable interference power as functions of discrimination angle and distance for assumed system parameters. The proposed method will play a practical role in technical analysis on co-existence or interoperability for the various wireless systems needed for frequency coordination.

• Journal of Korea Multimedia Society
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• v.19 no.7
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• pp.1179-1187
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• 2016

Through the rapid development of latest hardware technology, high performance as well as miniaturized size is the essentials of embedded system to meet various requirements from the society. It raises possibilities of genuine realization of IoT environment whose size and battery must be considered. However, the limitation of battery persistency and capacity restricts the long battery life time for guaranteeing real-time system. To maximize battery life time, low power technology which lowers the power consumption should be highly required. Previous researches mostly highlighted improving one single type of memory to increase ones efficiency. In this paper, reversely, considering multiple memories to optimize whole memory system is the following step for the efficient low power embedded system. Regarding to that fact, this paper suggests the study of volatile memory, whose capacity is relatively smaller but much low-powered, and non-volatile memory, which do not consume any standby power to keep data, to maximize the efficiency of the system. By executing function in specific memories, non-volatile and volatile memory, the quantitative analysis of power consumption is progressed. In spite of the opportunity cost of all of theses extra works to locate function in volatile memory, higher efficiencies of both power and energy are clearly identified compared to operating single non-volatile memory.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.963-969
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• 2018

Wi-Fi and Bluetooth technologies are perhaps the most prominent examples of wireless communication technologies used in the Internet of Things (IoT) environment. Compared to widely used Wi-Fi, Bluetooth technology has some flaws including 1:1 connection (one-way) between Master and Slave, slow transmission, and limited connection range; Bluetooth is mainly used for connecting audio devices. Since the release of Bluetooth Low Energy (BLE), some of the flaws of Bluetooth technology have been improved but it still failed to become a competitive alternative of Wi-Fi. This paper presents a method of data transmission through broadcasting in BLE and demonstrates its performance, one-to-many data transfer result. The Connection-Free Data Transmission proposed in this paper will hopefully be utilized in special circumstances requiring 1:N data transmission or disaster security network.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.5
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• pp.231-238
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• 2017

A Class B device in LoRaWAN periodically receives a Beacon message from a gateway for synchronization, and it also periodically activates a ping slot to receive data from the server. In this paper, we save energy consumption by controlling the beacon-less operation which is immediately started on the packet loss. In addition, we propose a method that the server inactivates the ping slots of a device according to the amount of messages, which have to be received from the server, to save energy consumption resulting from activated but unused empty slots. The experiment with the 20% of packet loss rate showed that the reduced beacon-less operation and the inactivation of the ping slot decrease the energy consumption by 96.7% and 60% as compared to the existing method.