• Journal of the Institute of Convergence Signal Processing
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• v.22 no.4
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• pp.199-205
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• 2021

The distributing board in directly installed on the ground or the bottom surface of the building, and when vibrations such as earthquakes or external shocks occur, the possibility of damage or malfunction of electric components such as internal power devices, wiring, and protection relays increases. Recently, the need for a seismic type distributing board is increasing, and research and development of a distributing board having a vibration damping function and product launch are being conducted. In this paper, an IoT-based data collection device system capable of measuring vibration and environmental data of distributing board was designed and implemented. When vibration occurred on the distributing board, data was stored and visualized in the MySQL DB through Node-RED for monitoring and data storage using the MQTT protocol for reliable messaging transmission. The test was conducted by attaching the IoT device of the distributing board, and data was collected in real-time and monitored through Node-RED.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.13-20
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• 2011

In this paper, we proposed a system to raise gas safety management by using the wireless communication module and intelligent gas safety appliances. Our designed systems configure a micom-gas meter, an automatic extinguisher, sensors, and a wallpad. A micom-gas-meter monitors gas flow, gas pressure, and earthquake. An automatic fire extinguisher checks gas(combustible) leaks and temperature of $100^{\circ}C$ and $130^{\circ}C$. Sensors measure smoke and CO gas. In our novel system, a micom-gas meter cut off inner valve with warnings, an automatic fire extinguisher cut off middle valve and spray extinguishing materials, and sensors generate signals for smoke and CO when occurring gas risk. Gas safety appliances and sensors takes safety measures, and transmit those signal to a wallpad. The wallpad again transmit signal like events to a control server. Users can connect web pages for gas safety through B-ISDN and control and manage them. We hereby devised scenarios for gas safety and risk management, and demonstrated their effectiveness through experiments.

• Journal of IKEEE
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• v.22 no.2
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• pp.495-498
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• 2018

In this paper, we propose an DAP system for dose evaluation of medical and industrial X-ray generator. Based on the DAP measurement technique using the Ion-Chamber, the proposed system can clearly measure the exposure radiation dose generated by the diagnostic X-ray apparatus. The hardware part of the DAP measures the amount of charge in the air that is captured by an X-ray. The high-speed processing algorithm part for cumulative radiation dose measurement through microcurrent measures the amount of charge captured by X-ray at a low implementation cost (power) with no input loss. The wired/wireless transmission/reception protocol part synchronized with the operation of the X-ray generator improves communication speed. The PC-based control program part for interlocking and aging measures the amount of X-ray generated in real time and enables measurement graphs and numerical value monitoring through PC GUI. As a result of evaluating the performance of the proposed system in an accredited testing laboratory, the measured values using DAP increased linearly in each energy band (30, 60, 100, 150 kV). In addition, since the standard deviation of the measured value at the point of 4 division was ${\pm}1.25%$, it was confirmed that the DAP showed uniform measurements regardless of location. It was confirmed that the normal operation was not less than ${\pm}4.2%$ of the international standard.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.879-888
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• 2000

In this paper, the performance of IS-95B CDMA system adopting multi-code scheme for data service on the forward link is obtained by theoretical analysis and computer simulation. The wireless channel is assumed to include AWGN, MUI(Multi-User Interference), and MPI(Multi-Path Interference), and multipath Rayleigh fading modeled by TDL(Tapped Delay Line). To obtain actual performance, IS-95B system using PN codes(M-sequence) concatenated with Walsh codes is considered. The BER performance of voice/data service satisfying QoS requirement and the maximum capacity of voice users is derived in terms of various system parameters(voice activity factor, required SNR of voice/data users, the number of multi-codes, the number of voice/data users.,etc.). As a result, under the condition that the maximum allowable number of voice user is 38 in voice only system, as the number of multi-code is decreased by 1, the maximum allowable number of voice user is increased by 5% for system with 1 data user and 22.3% for system with 4 data users. Therefore, it is possible to increase maximum allowable number of users in IS-95B CDMA system by appropriate control of the number of multi-codes and required SNR according to channel environment and traffic characteristic.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.1
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• pp.41-49
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• 2008

Many machineries and equipments are being changing to various and complicated by development of recent technology and arrival of convergence age in distant future. These various and complicate equipments need more precise outcomes and low-power consumption sensors to get close and exact results. In this paper, we proposed fault tolerance and feedback theorem for sensor network and MEMS circuit which has a benefit of energy efficiency through wireless sensor network. The system is provided with independent sensor communication if possible as unused action, using idle condition of system and is proposed the least number of circuits. These technologies compared system efficiency after examining product of each Moving Distance by developed sensor which gives effects to execution of system witch is reduced things like control of management side and requirement for hardware, time, and interaction problems. This system is designed for practical application; however, it can be applied to a normal life and production environment such as "Ubiquitous City", "Factory Automata ion Process", and "Real-time Operating System", etc.

• International Journal of Computer Science & Network Security
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• v.23 no.4
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• pp.55-68
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• 2023

In recent years, the Television White Space (TVWS) has attracted the interest of many researchers due to its propagation characteristics obtainable between 470MHz and 790MHz spectrum bands. The plenty of unused channels in the TV spectrum allows the secondary users (SUs) to use the channels for broadband services especially in rural areas. However, when the number of SUs increases in the TVWS wireless network the aggregate interference also increases. Aggregate interferences are the combined harmful interferences that can include both co-channel and adjacent interferences. The aggregate interference on the side of Primary Users (PUs) has been extensively scrutinized. Therefore, resource allocation (power and spectrum) is crucial when designing the TVWS network to avoid interferences from Secondary Users (SUs) to PUs and among SUs themselves. This paper proposes a model to improve the resource allocation for reducing the aggregate interface among SUs for broadband services in rural areas. The proposed model uses joint power and spectrum hybrid Firefly algorithm (FA), Genetic algorithm (GA), and Particle Swarm Optimization algorithm (PSO) which is considered the Co-channel interference (CCI) and Adjacent Channel Interference (ACI). The algorithm is integrated with the admission control algorithm so that; there is a possibility to remove some of the SUs in the TVWS network whenever the SINR threshold for SUs and PU are not met. We considered the infeasible system whereby all SUs and PU may not be supported simultaneously. Therefore, we proposed a joint spectrum and power allocation with an admission control algorithm whose better complexity and performance than the ones which have been proposed in the existing algorithms in the literature. The performance of the proposed algorithm is compared using the metrics such as sum throughput, PU SINR, algorithm running time and SU SINR less than threshold and the results show that the PSOFAGA with ELGR admission control algorithm has best performance compared to GA, PSO, FA, and FAGAPSO algorithms.

• Journal of the Korean Institute of Gas
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• v.24 no.5
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• pp.10-19
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• 2020

Valve leak accidents in petrochemistry plants and gas utilities cause human and property damage. The main reason why happen gas inhalation, poisoning, fire and explosion accidents is gas valve leakage. To prevent gas leakage, inspectors check the facilities in the field. And they are at risk of gas leak accidents. So we applied IoT-based risk assessment, monitoring and automatic control system. It can detect both internal and external gas leakage, do real-time monitoring of industrial valve in the plant by using hybrid sensor. As the new safety management system for industrial valve is developed, it needs method to evaluate device performance and environmental components for the system. This study is about development of method to verify performance of the explosion-proofed hybrid sensing system include gas detector and optical fiber sensor supporting wire and wireless communication.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.3
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• pp.249-258
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• 2010

This study seeks to improve NFRDI Serial Oceanographic observation (NSO) system which has been operated at current observation stations in the Korean Seas since 1961 and suggests the direction of NSO for practical use of Korean operational oceanographic system. For improvement, data handling by human after CTD (Conductivity-Temperature-Depth) observation on the deck, data transmission, data reception in the land station, and file storage into database need to be automated. Software development to execute QA/QC (Quality Assurance/Quality Control) of real-time oceanographic observation data and to transmit the data with conversion to appropriate format automatically will help to accomplish the automation. Inmarsat satellite telecommunication systems with which have already been equipped on board the current observation vessels can realize the real-time transmission of the data. For the near real-time data transmission, CDMA (Code Division Multiple Access) wireless telecommunication can provide efficient transmission in coastal area. Real-time QA/QC procedure after CTD observation will help to prevent errors which can be derived from various causes.

• Journal of Satellite, Information and Communications
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• v.4 no.1
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• pp.1-7
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• 2009

As the information age comes out, the aspect of future war brings about the many changes in terms of war-fighting environment. Accordingly, information superiority and intelligence-centric warfare have been important and new war-fighting concept such as NCW(network centric warfare) have been turned up. This paper proposed all-weather core-strategy communications systems guaranteeing not only the real-time transmission of the information collected in a battlefield and expansion, automation, and rapidity of a battlefield but also broadband, mobility, survivability, and flexibility. The proposed military satellite communications system is classified into wideband mass capacity link, survivability, and the system supporting OTM(on the move) communication for the real-time transmission of battlefield information. This paper analyzed the essential operation concepts and core schemes of the U.S. Army's next generation system, TSAT(Transformational Satellite Communication System). Base on the analysis results, this paper proposed that the architecture of next generation military satellite communications systems for NCW have to provide the data rate, anti-jamming capability, network control and management capability which are optimally adaptable for the wireless channel environments such as jamming and interference and to support the variety of platforms like high-speed mobile vehicles, micromini devices, super-high speed unmanned aerial vehicles. Finally, this paper also proposed that next generation military satellite communications systems need the technologies such as the adaptable multi-antenna, laser link, and next-generation anti-jamming waveform.

• Journal of IKEEE
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• v.17 no.4
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• pp.407-417
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• 2013

In this paper, a reconfigurable peripheral unit for LED lighting communication is presented. Embedded lighting devices require various communication protocols. Usually, serial communication protocols and lighting control communication protocols such as DALI, DMX512, UART, SPI, IrDA, etc. are used in lighting devices. When the requirements of communication protocols are satisfied with separate IPs, the cost and the power consumption can considerably increase. We propose a reconfigurable communication peripheral unit which uses analysis of signal formats of the protocols. The gate count of the reconfigurable peripheral unit uses only 57% of the gate count of the separate implementation. Also, in this paper, a mapping table based DALI-ZigBee interfacing method for flexible lighting network configurations is proposed. Using this method, various DALI-ZigBee network systems can be easily set up. An LED lighting system platform is implemented to verify the operation of the DALI-ZigBee interfacing method. The reconfigurable peripheral unit and the DALI-ZigBee interfacing method can be efficiently used to implement various wired/wireless lighting communication systems.