• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.11
• /
• pp.1257-1264
• /
• 2015

With the successful deployment of 4G mobile communications such as Long-Term Evolution(: LTE), global leading countries including Europe, China, and Japan have been made an effort to take the lead in technology, standardization, and market with targeting the commercialization of 5G mobile communication in 2020. In order to judge the future evolution of a 5G mobile communication system, this paper discusses the comprehensive trends and the requirements set by each countries for the 5G mobile communication systems.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.12
• /
• pp.74-80
• /
• 2013

Generator faults does not happen more often than the transmission and substation facility faults. However, impacts on the power system by generator faults are very large. In order to minimize the impact of generator faults, generator protection and control system with high reliability is required. Most of the generator relay in generator protection and control system of large power plant of Korea is operated by imports from abroad. Accordingly, in order to accumulate source technology and increase the import substitution effect, localization of multi-function generator protection IED is being developed. This paper deals with the implementation of a multi-function prototype IED H/W, which can be command and data exchange through communication for measuring, monitoring, protection and control. And the IED specification, various relay elements, measurement elements, communication functions, module function, and test system for the prototype IED H/W are described.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.55 no.6
• /
• pp.227-235
• /
• 2006

In this paper, autonomous separation methodology of faulted section based on network is proposed newly, which can minimize the outage effect as compared with the existing center-based faulted section separation method by determining and separating autonomously the faulted section by the free operation information exchange among IEDs on the feeder of distribution system. The all IEDs is designed in network in which client/server function is possible in order to separate autonomously the faulted section using PtP(Peer to Peer) communication. Also, Inference based solution of IED for the autonomous faulted section separation is designed by rules obtained from the analyzing results of distribution system topology. Here, the switch IEDs transmit on network the fault information utilizing on multi-casting communication method, at the fame time, determine selfly whether they operates or not by inferencing autonomously the faulted section using the inference-based solution after receiving the transmitted information. Finally, in order to verify the effectiveness and application possibility of the proposed methodology, the diversity fault cases are simulated for the typical distribution system.

• International Journal of Internet, Broadcasting and Communication
• /
• v.10 no.3
• /
• pp.42-50
• /
• 2018

The majority of existing falling recognition techniques provide service by recognizing only that the falling occurred. However, it is important to recognize not only the occurrence of falling but also the situation before and after the falling, as well as the location of the falling. In this paper, we design and propose the falling notification service system to recognize and provide service. This system uses the acceleration sensor of the smartphone to recognize the occurrence of a falling and the situation before and after the falling. In order to check the location of falling, GPS sensor data is used in the Google Map API to map to the map. Also, a crosswalk map converted into grid-based coordinates based on the longitude and latitude of the crosswalk is stored, and the locations before and after falling are mapped. In order to reduce the connection speed and server overload for real-time data processing, fog computing and cloud computing are designed to be distributed processing.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.4
• /
• pp.85-90
• /
• 2014

We realized a wireless multiple integrated laser engagement system composed of personal area network using Zigbee. The wireless laser detector had function of analog signal processor, decoder and wireless communication. However, it should consume low power and be small and light in order to be attached to a soldier's body. The decoder was realized in software to be small and light. We induced low power consumption as reducing the load of system using a narrow band optical filter. The fabricated wireless laser detector functioned well in optically noisy environment. Although the communication to the player unit through the wireless personal area network was dependent on the attachment place it was perfectly worked with transmission power of -40.2dBm or more.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.4
• /
• pp.1396-1414
• /
• 2018

With the proliferation of the Internet of Things (IoT) healthcare devices, significant interoperability issue arises where devices use proprietary data transfer protocols. The IHE PCD-01 standard has been suggested for the exchange of healthcare data in ISO/IEEE 11073 PHD data model. However, the PCD-01 is not efficient to be used in the IoT environment. This is because the use of SOAP for PCD-01 may be too complex to be implemented in the resource-constrained IoT healthcare devices. In this paper, we have designed a communication system to implement ISO/IEEE 11073 and IHE PCD-01 integration using the IETF CoAP. More specifically, we have designed the architecture and procedures, using CoAP, to seamlessly transmit the bio-signal from the tiny resource-constrained IoT healthcare devices to the server in a standardized way. We have also built the agent, gateway, and PCD-01 interface at the server, all of which are using the CoAP as a communication protocol. In order to evaluate the performance of the proposed system, we have used the PCD data to be transmitted over CoAP, MQTT, and HTTP. The evaluation of the system performance shows that the use of CoAP results in faster transaction and lesser cost than other protocols, with less battery power consumption.

• KEPCO Journal on Electric Power and Energy
• /
• v.2 no.4
• /
• pp.563-567
• /
• 2016

In this paper, the chaos-based secure scheme for power line communication is proposed for the first time. A digitalized chaotic generator based Lorenz system is utilized for generating nonlinear dynamic chaotic signal for masking the information signal instead of reported analog chaotic generators. A simple method of encryption and decryption is also given. In order to confirm the feasibility of the proposed scheme, the system is simulated using a simplified encryption/decryption method in Proteus. The gained results from simulation demonstrated that by using the chaos-based security method, the data can be encrypted and easily transmitted through the power line network efficiently.

• Journal of Korea Multimedia Society
• /
• v.8 no.9
• /
• pp.1248-1257
• /
• 2005

This paper designs and implements a sentence generation for an augmentive and alternative communication system(AAC). The AAC system is assistive communication device to help the mute language disorder communicate more freely and the system have an objected to reduce time and keystrokes for sentence generating. The paper of sentence generation make up for merits and demerits in the existing sentence generation method and in order to sentence generation. One aspect of Korean language that confines nouns defending on the verbs or postpositional words is used for sentence generation. The distinctive feature of this paper is to connect verbs to nouns using domain knowledge. We utilize the lexical information that exploits characteristics of Korean language for sentence generation. A comparison with other approaches is also presented. This sentence generation is based on lexical information by extracting characteristics of sentences.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2002.05a
• /
• pp.152-155
• /
• 2002

In recent years, with the spread of communication media, such as a cellular phone and E-mail, we are able to communicate with others without any restriction of position or time. However, complexity of communicative context has increased so that user has to guess a partner user's situation and status in order to use various medias efficiently. This problem will grow larger as new media are brought in the expanding communications network. To solve this problem, we propose the system that guesses the context in communication by a user's media from the position information on PHS (Personal Handy phone System) and schedule information from schedule application. In this system a user's agent guesses automatically the context that owner has set, and answers the demand of the context from a partner user. Moreover, the agent decides a suitable answer, when there is a demand of communication by the media, which cannot be used.

• The Journal of the Acoustical Society of Korea
• /
• v.21 no.7
• /
• pp.606-613
• /
• 2002

In this paper we applied a transmit beamforming technique to the underwater acoustic communication system for high rate data transmission. A prototype transmit system was designed and implemented with the general purpose DSP processor and multiple digital-to-analog converters. The performances of the implemented system were evaluated by the experiment in water tank. In order to simplify the procedure the channel coding and equalizer were omitted. And the simplest OOK (On-Off Keying) technique in digital communication methods was applied. The experimental result shows that the transmission data rate is higher about 3 times in the case of 5 hydrophone transmitting may than 1 hydrophone transmitter at bit error rate 10/sup -2/. We verified that the maximum data rate was 400 bps for speech signal transmission in water tank.