• Fire Science and Engineering
• /
• v.24 no.2
• /
• pp.178-184
• /
• 2010

In this study, a smoke or a heat which occurs by a fire is perceived by wireless detector, this signal is transmitted to the receiving device by the wireless installation which is not the wire device and wire/wireless integration system which sends this signal to main server via wire system is proposed. In addition wireless heat/smoke detector, wireless module, firmware and wire/wireless integration controller were developed and for verifying regarding the efficiency and applicability of wire/wireless installation actual place application experiment was really accomplished with a transmission tower, a multipurpose building, and a station etc of the subway. The experimental result, it could operate the system which is proposed normally with all experimental object ones and, future actual place application possibility could verify.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.11
• /
• pp.1651-1657
• /
• 2015

In MHz operating wireless power transfer systems, skin- and proximity-effect losses in the transmitter and the receiver coils dominate the coil-to-coil efficiency of the system. A Litz-wire was regarded as a common solution for minimizing such Ohmic losses in high frequencies. In this paper, equivalent series resistances of 12 different cables including Litz-wire and copper tubing have been calculated and measured for a 6.78 MHz, 100W, 30 cm wireless power transfer system. It has been shown that the copper tubing has lower resistances compared to the Litz-wire in that frequency and a wireless power transfer system with the copper tubing was able to achieve much higher efficiency than a system using the Litz-wire. Calculations of the resistances and efficiencies were accomplished with analytical equations and those calculations were evaluated by experimental results.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2000.11a
• /
• pp.227-230
• /
• 2000

Chuas circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chuas circuits are proposed and synchronizations of a equivalent wire and wireless power line are investigated. Since the synchronization of the equivalent wire and wireless system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. As a result, the chaos synchronization has delay characteristics in the equivalent wire and wireless transmission system caused by the line parameters L and C.

• Proceedings of the Korea Contents Association Conference
• /
• 2006.11a
• /
• pp.599-603
• /
• 2006

Korea Information Security Agency has executed the certification system for the information security management since 2002 and examines the conformance of the IDCs'total management system including the technical and the physical protection measure. However, this certification system has the standard only for the IDC in the wire/wireless segregated and the evaluation method for the wire/wireless integrated has not been suggested yet. This paper is on the basis of "Accumulation Information Communication Facility Secure Principle", guidelines of Wireless LAN security operation, the existing principles and recommendations of the information security and the data on IDC environment. And the paper suggests the IDC network model in the wire/wireless integrated and the IDC evaluation method.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2000.11a
• /
• pp.231-234
• /
• 2000

In this paper, we formed a transmitter and receiver by using three identical Chuas circuits and then formed wire and wireless transmission line from the channel which was between those three circuits. We proposed a secure communication method in which the desired information signal was synthesized with the chaos signal created in a Chuas circuit and sent to the transmitter through channel. Then the signal was demodulated receiver of Chuas circuit. The method we used to accomplish the secure communication was synthesizing the desired information with the chaos circuit by parallel connection in a wireless transmission line. After transmitting the synthesized signal to the wire and wireless transmission line, we confirmed the actuality of the secure communication by separating the information signal and the chaos signal in the receiver.

• Transactions of Materials Processing
• /
• v.32 no.6
• /
• pp.303-310
• /
• 2023

Electrohydraulic forming(EHF), one of the high-speed forming method, can supplement the weak point of previous forming process such as deep-drawing and electromagnetic forming. Indeed, EHF is time-consuming process during installing wire before experiment that hard to apply to industry. In this research, applying wireless electrode, the formability of SUS430 sheet was compared through EHF experiments using wire-installed electrode and the other, wireless. Although the power was a little lacking, the advantages of the experiment using wireless electrode could be confirmed with checking the optimal location of electrodes where the plasma is generated and comparing free-bulging height depending on former and later condition of electrodes with performing several single and multistage experiments for same voltage, 6 kV.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.2
• /
• pp.306-312
• /
• 2014

The ZigBee communication method, which is the most frequently applied to the LED lighting control system, has drawbacks of low-speed and low-capacity, and the communication failure possibility due to environmental influences is on the rise. Therefore, it is important to secure the communication reliability by applying an integrated interface with a wire-wireless dual-network. This paper developed a communication module, which has a platform converging and combining the ZigBee of USN environments with the PLC of power line communication environments, to implement a dualized communication interface system supporting the wire-wireless integrated protocol, and implemented a wire-wireless networking device and a control system software technology. As a result, it was automatically switched into the PLC communication within 4.4 seconds on average when there was an access failure in the ZigBee communication network, so a reliable communication network was built.

• The Journal of the Acoustical Society of Korea
• /
• v.22 no.3
• /
• pp.182-187
• /
• 2003

In this thesis, we propose the algorithm to improve the performance of speaker verification that is mapping feature parameters by using RBF neural network. There is a big difference between wire vector region and wireless one which comes from the same speaker. For wire/wireless speakers model production, speaker verification system should distinguish the wire/wireless channel that based on speech recognition system. And the feature vector of untrained channel models is mapped to the feature vector(LPC Cepstrum) of trained channel model by using RBF neural network. As a simulation result, the proposed algorithm makes 0.6%∼10.5% performance improvement compared to conventional method such as cepstral mean subtraction.

• Journal of the Korea Society of Computer and Information
• /
• v.7 no.2
• /
• pp.46-52
• /
• 2002

Trend of wire internet has been transferred to wireless internet gradually due to the spread of mobile phone which made Possible Mobility and portability which wire internet could not afford. Not only front line of business part can access business information but also people can use government information for their daily life without limit of place. The frequent report of larceny and misuse of information has been issued to social sector that the need for IDS considering wire wireless internet. In this paper to design IDS to protect information first, searched wire internet intrusion type, intrusion detection method, and wireless intrusion type. In this paper, first, separate abnormal access at the point of system landing and detect intrusion attack with disguise through mobile wireless internet. Due to the intruder can access system normally with disguise, Circuit Patrol model has been suggested to monitor from intrusion attack.

• Journal of Power Electronics
• /
• v.18 no.4
• /
• pp.1268-1277
• /
• 2018

A relatively high operating frequency is required for efficient wireless power transfer (WPT). However, the alternating current (AC) resistance of coils increases sharply with operating frequency, which possibly degrades overall efficiency. Hence, the evaluation of coil AC resistance is critical in selecting operating frequency to achieve good efficiency. For a Litz wire coil, AC resistance is attributed to the magnetic field, which leads to the skin effect, the proximity effect, and the corresponding conductive resistance and inductive resistance in the coil. A numerical calculation method based on the Biot-Savart law is proposed to calculate magnetic field strength over strands in Litz wire planar spiral coils to evaluate their AC resistance. An optimized frequency can be found to achieve the maximum efficiency of a WPT system based on the predicted resistance. Sample coils are manufactured to verify the resistance analysis method. A prototype WPT system is set up to conduct the experiments. The experiments show that the proposed method can accurately predict the AC resistance of Litz wire planar spiral coils and the optimized operating frequency for maximum efficiency.