• International Journal of Computer Science & Network Security
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• v.23 no.11
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• pp.149-161
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• 2023

Internet of Things (IoT) is a relatively new concept that has gained immense popularity in a short period of time due to its wide applicability in making human life more convenient and automated. As an illustration: the development of smart homes, smart cities, etc. However, it is also accompanied by a substantial number of risks and flaws. IoT makes use of low-powered devices, so secure, less time-consuming and energy-intensive transmission (routing) of messages due to the limited availability of energy is one of the many and most significant concerns for IoT developers. The following paper presents a trust-based routing scenario for the Internet of Things (IoT) that exploits the past transmission record from the cupcarbon simulator's log files. Artificial Neural Network is used to quantify knowledge of trust, calculate the value of trust, and share this information with other network devices. As a human behavioural pattern, trust provides a superior method for making routing decisions. If there is a tie in the trust values and no other path is available, the remaining battery power is used to break the tie and make a forwarding decision; this is also seen as a more efficient use of the available resources. The proposed algorithm is observed to have superior energy consumption and routing decisions compared to conventional routing algorithms, and it improves the communication pattern.

• Journal of Electrical Engineering and Technology
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• v.2 no.3
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• pp.294-299
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• 2007

This paper presents a special protection scheme, which was established in the KEPCO (Korea Electric Power Corporation) system, against a critically low voltage profile in a part of the system after a double-circuit tower outage. Without establishing the scheme, the outage triggers the operation of a zone 3 relay and trips the component. This sequence of events possibly leads to a blackout of the local system. The scheme consists of an inter-substation communication network using PITR (Protective Integrated Transmitter and Receiver) for acquisition of the substations' data, and under-voltage load shedding devices. This paper describes the procedure for determining the load shedding in the scheme and the experiences of the implementation.

• Journal of electromagnetic engineering and science
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• v.7 no.3
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• pp.103-108
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• 2007

In this paper, a low-power 2.4 GHz front-end for sensor network application (IEEE 802.15.4 LR-WPAN) is designed in a 0.18 um CMOS process. A power supply circuit with a novel temperature-compensation scheme is presented. The simulation and measurement results show that the front-end (LNA, Mixer) can achieve a voltage gain of 35.3 dB and a noise figure(NF) of 3.1 dB while consuming 5.04 mW (LNA: 2.16 mW, Mixer: 2.88 mW) of power at $27^{\circ}C$. The NF includes the loss of BALUN and BPF. The low-IF architecture is used. The voltage gain, noise figure and third-order intercept point (IIP3) variations over -45$^{\circ}C$ to 85$^{\circ}C$ are less than 0.2 dB, 0.25 dB and 1.5 dB, respectively.

• Proceedings of the KIEE Conference
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• summer
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• pp.233-235
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• 2004

Operation of wind turbines has impacts on the voltage quantity at the connected electricity network. Increasing penetration of wind energy makes necessary to study the power quality regarding voltage variations(sag, swell, interruption) and presence of harmonics in the id. This paper investigates the voltage quality of low voltage customers connected to wind generation system. To study the influences of wind power generation to low voltage power system, voltage data are collected in three house using PQM(Power Quality Monitoring) equipment during one month and analyzed regarding voltage variation and harmonics

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.274-277
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• 2012

In this paper, we proposes the design of laundry system for low power and smart management. The low power system configures the network with the RF communication module that turn on/off periodically, power consumption less than operating the module all the time without it toggles. The smart management is RFID Laundry Management System (LMS), in order to provide high services, low operation costs and better monitoring. The proposed system consists of RFID tag, wireless RFID hanger and MFC software. To compare with other existing RFID system, our system was developed as a web application. Therefore, customer can check their cloth status through web page or smartphone devices. RFID reader was designed on hanger to make our system enables reliable running effectively. Some results on the performance of an implementation are presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.197-200
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• 2011

Many routing protocols have been proposed for low-power and ad-hoc networks where energy awareness and reliability are essential design issues. This paper proposes a dynamic routing protocol for low-power and ad-hoc networks. A dynamic path cost function is defined considering the constraints and characteristics of low-power and ad-hoc networks. The cost function can be applied flexibly depending on the characteristics of the networks. The performance of the proposed method is evaluated using a QualNet network simulator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1955-1960
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• 2014

Many routing protocols have been proposed for low-power and ad-hoc networks to deliver command or data among nodes and recently, various researches are carried out about networking scheme considering reliability and scalability. In low-power networking technology, the performance of network layer is closely connected with the operation of data link layer and mesh routing mechanisms based on TDMA MAC are considered for reliability and scalability. This paper proposes mesh routing algorithm utilizing the characteristics of TDMA MAC and topological addressing in TDMA based low-power and ad-hoc networks and implementation results are presented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.280-288
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• 2009

In this paper, a high-power and low-loss stripline 10-way power divider is designed and fabricated fur the feed network of an S-band linear array antenna with Chebyshev current distribution which has a narrow beam width and low side lobe level(SLL) of 35 dB or more. The unit cell of the power divider is based on a T-junction power divider and the whole divider is comprised of the cascaded unit cells. The multi-stage impedance transformer and modified ring hybrid are used in designing the power divider for performance improvement. And the reflection loss and insertion loss are improved by modifying a connector structure for a coaxial-to-stripline transition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.466-474
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• 2014

According to wireless network technology and mobile processors performance were improved, the small wireless mobile device such as smart phones has been widely utilized. The mobile devices can be used GPS information, thereby the services based on location information was increased. GPS was impossible to provide location information in indoor and signal shading environment, and the tracking systems based on short distance wireless communication are required infrastructure. The IEEE 802.11 based tracking system is possible estimation using APs, however the tracking device is exhausted battery power seriously. In this paper, we propose IEEE 802.11 based low-power tracking system. We reduced power consumption from channel scanning and network connection. For performance evaluation, we designed and implemented the tracking tag device, and measured power consumption of the device. As the simulation result, we confirmed that the power consumption was reduced 46% compare to the standard execution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.114-121
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• 2003

In this paper, low voltage and two stage CMOS Class E RF power amplifier for ISM(Industrial/Scientific/Medical) Open Band is presented. The power amplifier operates at 2.4GHz frequency, and is designed and simulated with a 0.35um CMOS technology and HSPICE simulator. The power amplifier is simple structure of two stage Class E power amplifier. The design procedure determing matching network was presented. The power amplifier is composed of input stage matching network, preamplifier, interstage matching network, power amplifier, and output stage matching network. The matching networks of input stage and interstage were constituted by pi($\pi$) type and L type respectively. At 2.4GHz operating frequency, and with a 2.5V supply voltage, the power amplifier delivers 23dBm output power to a 50${\Omega}$ load with 39% power added efficiency(PAE).