• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.433-443
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• 2022

Purpose: In this paper, we propose a study of deep learning algorithms that estimate and predict sarcopenia by exploiting the high penetration rate of smart devices. Method: To utilize deep learning techniques, experimental data were collected by using the inertial sensor embedded in the smart device. We implemented a smart device application for data collection. The data are collected by labeling normal and abnormal gait and five states of running, falling and squat posture. Result: The accuracy was analyzed by comparative analysis of LSTM, CNN, and RNN models, and binary classification accuracy of 99.87% and multiple classification accuracy of 92.30% were obtained using the CNN-LSTM fusion algorithm. Conclusion: A study was conducted using a smart sensoring device, focusing on the fact that gait abnormalities occur for people with sarcopenia. It is expected that this study can contribute to strengthening the safety issues caused by sarcopenia.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.307-311
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• 2022

With the development of Internet of Things (IoT) technologies, numerous people worldwide connect with various electronic devices via Human-Machine Interfaces (HMIs). Considering that HMIs are a new concept of dynamic interactions, wearable electronics have been highlighted owing to their lightweight, flexibility, stretchability, and attachability. In particular, wearable strain sensors have been applied to a multitude of practical applications (e.g., fitness and healthcare) by conformally attaching such devices to the human skin. However, the stretchable elastomer in a wearable sensor has an intrinsic stretching limitation; therefore, structural advances of wearable sensors are required to develop practical applications of wearable sensors. In this study, we demonstrated a 3-dimensional (3D), porous, and piezoelectric strain sensor for sensing body movements. More specifically, the device was fabricated by mixing polydimethylsiloxane (PDMS) and polyvinylidene fluoride nanoparticles (PVDF NPs) as the matrix and piezoelectric materials of the strain sensor. The porous structure of the strain sensor was formed by a sugar cube-based 3D template. Additionally, mixing methods of PVDF piezoelectric NPs were optimized to enhance the device sensitivity. Finally, it is verified that the developed strain sensor could be directly attached onto the finger joint to sense its movements.

• Journal of IKEEE
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• v.26 no.1
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• pp.62-66
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• 2022

Recently, there have been many research efforts based on data-based deep learning technologies to deal with the interference problem between heterogeneous wireless communication devices in unlicensed frequency bands. However, existing approaches are commonly based on the use of complex neural network models, which require high computational power, limiting their efficiency in resource-constrained network interfaces and Internet of Things (IoT) devices. In this study, we address the problem of classifying heterogeneous wireless technologies including Wi-Fi and ZigBee in unlicensed spectrum bands. We focus on a data-driven approach that employs a supervised-learning method that uses received signal strength indicator (RSSI) data to train Deep Convolutional Neural Networks (CNNs). We propose a simple measurement methodology for collecting RSSI training data which preserves temporal and spectral properties of the target signal. Real experimental results using an open-source 2.4 GHz wireless development platform Ubertooth show that the proposed sampling method maintains the same accuracy with only a 10% level of sampling data for the same neural network architecture.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.827-837
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• 2017

Since the area of smart home has been attracting attention, researches have been conducted to control syntagmatically various electronic products with a single remote controller. Previous researches have developed a dedicated controller or an application that acts as a remote controller and controls electronic products by configuring control screen for each product. However, these approaches are not suitable for controlling various electronic products that should be controlled by configuring separate control screens for each product. In this paper, we propose a web-based remote control platform. We define universal user interfaces applicable to various devices by categorizing user interactions of electronic goods and implement them as APIs. By applying the APIs to IPTV and car navigation devices we show that it is possible to control them through only a web browser. We also propose a method to group multiple control requests in order to efficiently handle consecutive control requests and show the improved response time and data usage.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.55-62
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• 2019

The needs for small size and low power consumption of information devices is being implemented with SOC technology that implements the program on a single chip in Internet of Thing. Copyright disputes due to piracy are increasing in semiconductor chips as well, arising from disputes in the chip implementation of the design house and chip implementation by the illegal use of the source code. However, since the final chip implementation is made in the design house, it is difficult to protect the copyright. In this paper, we deal with the analysis method for extracting similarity and the criteria for setting similarity judgment in the dispute of source code written in HDL language. Especially, the chip which is manufactured based on the same specification will be divided into the same configuration and the code type.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.703-710
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• 2017

Third-generation (3G) devicesare next-generation devices that allow the use of intelligent services and applications through the Internet of Things (IoT). As the market forexisting smart devices like smartphones and tablet PCs enters the stage of stagnation, the world is now focusing on 3G devices, parts, and services. This study is intended to measure the user's benefits from the various attributes of 3G devices by applying an economic valuation method. For this purpose, the conjoint analysis method was applied, which is one of the representative valuation methods. To apply conjoint analysis, the following attributes of 3G devicesare considered: mode of use, power efficiency, life care, and price. By applying the mixed logit model, the marginal willingness-to-pay(WTP) for each attribute was derived. The results are statistically significant. Respondents showed a high preference or complete flexibility in the mode of use attribute. And they were also found to have WTP for improvements in the life care attribute. The implications and quantitative results of this study are expected to be useful for policies and strategies in the 3G device market.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.8
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• pp.1588-1596
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• 2015

In the Internet of Things (IoT), resource-constrained devices such as sensors are capable of communicating and exchanging data over the Internet. The IETF standard group has specified an application protocol CoAP, which uses UDP as a transport protocol, allows such a lightweight device to transmit data. Also, the IETF recommended the DTLS binding for securing CoAP. However, additional features should be added to the DTLS protocol to resolve several problems such as packet loss, reordering, fragmentation and replay attack. Consequently, performance of DTLS is worse than TLS. It is highly required for lightweight devices powered by small battery to design and implement a security protocol in an energy efficient manner. This paper thus discusses about DTLS performance in the perspective of energy consumption. To analyze the performance, we implemented IEEE 802.15.4 based test network consisting of constrained sensor devices in the Cooja simulator. We measured energy consumptions required for each of DTLS client and server in the test network. This paper compares the energy consumption and amount of transmitted data of each flight of DTLS handshake, and the processing and receiving time. We present the analyzed results with regard to code size, cipher primitive and fragmentation as well.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.8
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• pp.353-358
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• 2017

An electrical power utility, like an electrical power pole, includes various kinds of sensors for smart services. Temperature data is considered one of the important factors that can influence the smart operations of this utility. This study suggests a method for temperature data analysis for deciding the status of the smart electrical power utilities by using Kalman Filter and Ensemble Model. The suggested approach separates the temperature data according to the different positions of the temperature sensors of a utility, then uses Kalman Filter and Ensemble Model to analyse the characteristics of the temperature variation. With detailed processes, method explains the variation between an external temperature factor like weather temperature data and the sensed temperature data, and then, analysis the temperature data from each position of electrical power utilities. In this process, the suggested method uses Kalman Filter to remove error data and the ensemble model to find out mean value of every hour of electrical data. The result and discussion of temperature analysis were described clearly with the analysed results of electrical data. Finally, we were able to check the working condition of the power devices and the range of the temperature data foe each devices, which may help to indicate any causalities with respect to the devices in the utility pole.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.53-63
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• 2020

Electronic financial transactions are also actively increasing due to the rapid spread of information communication media such as the Internet, smart devices, and IoT, but as a derivative by-product, threats of financial security such as leakage of various personal information and hacking are also increasing. Therefore, the importance of financial security against this is increasing, but in Korea, financial security technology is relatively insufficient compared to advanced countries in the field of financial security, such as Active-X. Therefore, this study aims to present the major development direction in the domestic financial security field by comparing key technology trends with IPC classification frequency analysis, keyword frequency analysis, and keyword network analysis based on domestic and foreign financial security-related patent data. In conclusion, it seems that recent domestic and foreign trends have focused on the development of related technologies according to the development of smart device-based electronic financial services. Accordingly, it is intended to be used as the basis data for technology development of financial security by mapping the trend of financial security research trend and technology trend analysis through thesis data analysis that reflects the research of the preceding aspect as the technology of commercialization in the future.

• Journal of Digital Contents Society
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• v.19 no.3
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• pp.505-512
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• 2018

Internet demand has increased rapidly, and Internet Protocol Version 4, the main Internet protocol, can not cope with various types of network demand in the future. Therefore, it is urgent to spread IPv6-based stable network to solve the shortage of Internet address resources. Due to the proliferation of IoT and the increase in mobile devices, efficient and optimal IPv6 routing design is indispensable. In this paper, we have studied about characteristics of IPv6, address system of IPv6, structure analysis and efficient routing technology among IPv6 terminals. Furthermore, experimental results on routing packet analysis and convergence time are presented in network - based IPv6 routing implementation environment. In addition, we show the results of the experiment analysis by dividing the implementation of IPv6 routing, operation test, and fail over performance into three kinds of routing protocol methods. As a result, this study can be applied to the introduction of IPv6 system, test bed environment construction, and network design.