• Journal of Korea Society of Industrial Information Systems
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• v.18 no.6
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• pp.17-24
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• 2013

The localization accuracy in wireless sensor networks using ranging-based localization algorithms is greatly influenced by the ranging accuracy. Software implementation of HAL(Hardware Abstraction Layer) and MAC(Medium Access Layer) should seamlessly deliver the raw performance of ranging-based localization provided by hardware capability fully to the applications without degrading the raw performance. This paper presents the design and implementation of the software stack for IEEE 802.15.4a which supports normal ranging mode of the Nanotron's NA5TR1 RF chip. The experiment results shows that average ranging error rate with our implementation is 24.5% for the normal mode of the SDS-TWR ranging scheme.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.5
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• pp.153-160
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• 2020

Energy Consumption Predictions for Industries has a prominent role to play in the energy management and control system as dynamic and seasonal changes are occurring in energy demand and supply. This paper introduces and explores the steel industry's predictive models of energy consumption. The data used includes lagging and leading reactive power lagging and leading current variable, emission of carbon dioxide (tCO2) and load type. Four statistical models are trained and tested in the test set: (a) Linear Regression (LR), (b) Radial Kernel Support Vector Machine (SVM RBF), (c) Gradient Boosting Machine (GBM), and (d) Random Forest (RF). Root Mean Squared Error (RMSE), Mean Absolute Error (MAE) and Mean Absolute Percentage Error (MAPE) are used for calculating regression model predictive performance. When using all the predictors, the best model RF can provide RMSE value 7.33 in the test set.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.615-616
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• 2017

Recently, research are being conducted to provide an automated environment utilizing various sensors in a place where management is use. However, in an existing automation system environment because the measured sensor data is processed in a batch in the server, than the currently action task there arises a problem that a conflict occurs between task when a task that should operate preferentially occurs. In this paper, we propose a system that provides automation using Sensor Data Identification Algorithm to solve these problems. The algorithm distinguishes between real-time and non-real-time tasks and automatically control tasks what happens after priority is applied. Through this, it is expected that it can reduce manager intervention and reduce unnecessary work operation and power consumption and construct an efficient automation environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.183-189
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• 2018

This paper proposes distributed file placement and coverage expansion techniques for mitigating the traffic bottleneck in backhaul for small-cell networks. In order to minimize the backhaul load with limited memory space, the proposed scheme controls the coverage and file placement of base station according to file popularity distribution and memory space of base stations. In other words, since the cache hit ratio is low when there is small memory capacity or widespread file popularity distribution, the base stations expand its coverage and cache different set of files for the user located in overlapped area to exploit multiple cached file sets of base stations. Our simulation results show that the proposed scheme outperforms the conventional cache strategy in terms of network throughput when there is small memory capacity or widespread file popularity distribution.

• Journal of the Korea Society of Computer and Information
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• v.20 no.2
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• pp.79-88
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• 2015

This paper introduces surveillance equipment "ADS-B", the core subject of traffic control system and study of ADS-B 1090ES ground receiver. The standard is set not only for functional but also its reliability by analyzing international standard documents and existing products. The Bias circuit is designed for less power consumption, low noise and high gain for RF module. The signal processing is capable of overcoming its bad conditions. MCU part is configured with the latest CPU for high speed communication with external parts and SNMP is selected for remote control communication. The performance of developed receiver satisfies national and international standards and its functions are more advanced compared to foreign receivers.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.203-210
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• 2008

Home networking has been noticed as a key technology for the home automation because it is possible to remotely monitor and control the in-house appliances and devices through the network. Wireless home networking method is easily applied to the conventional houses compared to the wired home networking method because of low cost and small effort due to no extra wired works. Especially, home networking using the ZigBee protocol is one of the most attractive technologies in the wireless networking area because of its low cost and low power consumption characteristics. However, there are a lot of practical problems to be solved in implementing the ZigBee module and constructing the wireless network. In this paper, one of the practical structures of the hardware and software modules for implementing the ZigBee protocol is proposed. Moreover, problems in constructing the home networking with the proposed ZigBee module are introduced, and the effective solutions to solve these problems are described through various tests.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.2
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• pp.380-385
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• 2006

In this paper, a program that can be utilized to measure and analyze radio propagation characteristics is developed. This program is able to control the measurement instruments including spectrum analyzer through GPIB interface and analyze the measured data to yield mean excess delay and RMS delay spread. The measured path loss can be compared with theoretical value in free space or inside a tunnel. The measured and analyzed results can also be presented in the forms of graphs. As these tasks can be conducted on the spot of the measurements, this program is very helpful in performing and verifying the measurements immediately. In this thesis radio propagation characteristics with frequency bands of 2.45 and 5.8GHz in subway tunnels are measured by using the program. Path loss and delay spread in subway tunnel is measured and compared according to the form of antenna beam and LOS(Line of Sight) and N-LOS(Non-Line of Sight).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.3
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• pp.101-109
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• 2012

Because the installation problem of parabola antenna that is tilted to 45 degree when this antenna is installed at the area of middle latitude, the study on planar antenna in place of parabola antenna is made rapid progess. Especially, The development of the planar antenna for VSAT is needed depending on the increased Ka-band satellite communications. In this paper, in order to meet with these performances, an array antenna consisting of the vertical polarized waveguide longitudinal slots based on the leaky-wave mode of traveling wave antenna is proposed. Especially, for the lower sidelobe level, the design method of the radiation power distribution control using the different slot widths is proposed. An array antenna consisting of 32 leakywave waveguide antennas is showing 35.16 dBi of gain, 2.5 degree of beamwidth at azimuth, below than -30 dB of sidelobe level, 45.8 degree of beam tilt angle in center frequency 30.2 GHz.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.2
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• pp.69-77
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• 2009

Small size and low profile antenna for mobile vehicular-top-mounted is needed in satellite communication services such as DBS, Satellite Internet and VSAT. In middle latitudes, the development of an array antenna which has the conformal, low profile and 45 degree beam tilted configuration, and has the high gain with sharp beamwidth, low sidelobe and low loss is required for Ka band satellite communication. In this paper, in order to meet with these performances, an array antenna consisting of the vertical polarized waveguide longitudinal slots based on the leaky-wave mode of traveling wave antenna is proposed. Especially, for the lower sidelobe level the radiation power control using a design method of the different slot width is proposed. An array antenna consisting of 32 leakywave elements is showing 34.4 dBi of gain, 3.6 degree of beamwidth, below than -25 dB of sidelobe level, 43 degree of beam tilt angle in center frequency 20.0 GHz. Feed network designed by waveguide cooperated feed shows good performance of wideband and low loss.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.5
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• pp.1201-1209
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• 2016

While the legacy electric grid evolving into the smart grid, various communication standards have been used for interoperability between many components. In this situation, the needs emerged for protocol conversion and mapping method for connecting the outside components to the operation center. In this paper, according to the surge of IEC 61850-based substation automation, we studied the protocol conversion gateway for linking legacy DNP3-based control center and IEC 61850-based substation automation. This paper is based on the IEEE 1815.1 standard for the protocol mapping. We suggested the direction of development the gateway and developed prototype for evaluate the proposed gateway. Also, we bring up a security problem and give a solution.