• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.101-107
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• 2007

In this paper, we have presented the results of Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) based fiber-to-the-home (FTTH) field trial test which was held in the city of Gwangju. We have implemented an injection locked Fabry-Perot Laser Diode (FP-LD) based WDM-PON system and reliably delivered Internet Protocol TV (IP-TV), networked Personal Video Recorder (N-PVR), High-Definition Video on Demand (HD-VoD), Education on Demand (EoD) and Internet service as FTTH service through the system during the field trial test. We have also verified that the WDM-PON system worked well to provide quality of service (QoS) guaranteed 100Mbps bandwidth per subscriber. Furthermore, we have presented network designing issues in Outside Plant (OSP) and Customer Premises Network (CPN) that should be overcome to efficiently deploy FTTH service. Finally, based on the field trial test results, we proposed FTTH service deployment strategies.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.1
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• pp.7-17
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• 2010

ITS(Intelligent Transport System) as things are used for Broadcast service using TDMB/TPEG/NAVI rather than personal seamless service. It is attaching weight to Traffic information gathering, Charging, Settlement service. This research is applied to improve DCCP(Datagram Congestion Control Protocol) which has function as protecting data and preserving message boundary. The improving method is like that we solve data trust in UDP because Connection and Transmission overhead in UDP is less than in TCP. We fix the data loss which is generated from unordered delivery section of IP base wireless service by using DCCP protocol. We guarantee of connection with OBE(On-Board Equipment) and reliance about transmission of data by complement to mapping table and multi-hoping. Finally, We evaluate the performance about transmission of IP based data. We constructed a test-bed near research center for this test.

• Journal of the Korean Home Economics Association
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• v.39 no.5
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• pp.1-14
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• 2001

The purpose of this study was to develop a evaluation system of customer service department operation in business. Four sources including related literature, managers of 4 outstanding customer service departments, SOCAP, and 7 OCAP administrative members provided useful information in various ways. The finally suggested evaluation system is consisted of three parts; work to do, resources needed, and operation standards. It is the type of checklist, which business can utilize it to examine whether they are doing well or not in terms of customer service department operation.

• The KIPS Transactions:PartB
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• v.15B no.3
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• pp.237-244
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• 2008

In this paper, an infra-structure using the ontology based on the pulse information is proposed for the context-aware service of medical information system in ubiquitous computing environment. An diagnosis service inference system that represents the pulse data which was generated by the pulse-diagnosis with wearable signal, temperature, humidity, time, and other factors as ontology with artificial intelligence methods and describes the service scenario based on the ontology is designed and implemented.

• Journal of the Korea Society of Computer and Information
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• v.23 no.11
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• pp.151-158
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• 2018

As the competition of 21 cyber universities in Korea has been on a continual increase, they are focusing on improving the quality of the e-learning education in cyber universities. In this study, we intended to derive the failure factors of the previous chatting system in the 2010s and the success factors from previous studies. Next, we identified priorities among five factors(Reliability, UI Convenience, Usability, Network effect, Operational policy) using AHP and the practical ways to implement the chatting service. We applied the chatting system to all the curriculums of S cyber university. Our study finds that the chat service affects the satisfaction of education. Finally, we propose the utilization plan to improve the e-learning education of cyber university through the findings of this research.

• Journal of Multimedia Information System
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• v.9 no.3
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• pp.209-218
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• 2022

Industrial IoT applications, including smart factories, require two problem-solving to build data monitoring systems required by services from distributed IoT sensors (smart sensors). One is to overcome proprietary protocols, data formats, and hardware differences and to uniquely identify and connect IoT sensors, and the other is to overcome the problem of changing the server-side data storage structure and sensor data transmission format according to the addition or change of service or IoT sensors. The IEEE 1451.4 standard-based or IPMI specification-based smart sensor technology supports the development of plug-and-play sensors that solve the first problem. However, there is a lack of research that requires a second problem-solving, which requires support for the plug-in of IoT sensors into remote services. To propose a solution for the integration of these two problem-solving, we present a IoT sensor platform, a service system architecture, and a service plugin protocol for the MQTT-based IIoT application environment.

• Electronics and Telecommunications Trends
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• v.38 no.3
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• pp.66-77
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• 2023

Governments intend to use the public warning system to deliver timely and accurate information using accessible communication technologies for protecting the population and reducing damage to life and property. In particular, many countries implement system interworking with smartphones to notify of disasters or emergencies. In Korea, since 2020, due to the influence of the coronavirus disease, frequent emergency text messages led people to turn off related notifications, and complaints for receiving irrelevant messages from nearby warning areas have increased. Therefore, technical improvements for issuing more accurate disaster information to a specific region should be devised through a geography-based emergency disaster message transmission service. We analyze development trends of public warning systems and service cases of geography-based emergency text transmission services in various countries.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.7-13
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• 2009

This paper presents benefits of multi-agent system approach and its application to the distribution automation system. Special attention is devoted to the description of hardware and communication platform used to upgrade the conventional distribution automation system structure. Service restoration of primary distribution system is selected as an example of the multi-agent system application. Application of the algorithm for multi-agent based service restoration technique is disclosed in detail. Real field test in Gochang test center of KEPCO has been performed to establish the feasibility of proposed technique.

• Journal of the Korean Mathematical Society
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• v.32 no.2
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• pp.211-236
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• 1995

The purpose of this paper is to provide a transient diffusion approximation of queue size distribution for M/G/m/N system. The M/G/m/N system can be expressed as follows. The interarrival times of customers are exponential and the service times of customers have general distribution. The system can hold at most a total of N customers (including the customers in service) and any further arriving customers will be refused entry to the system and will depart immediately without service. The queueing system with finite capacity is more practical model than queueing system with infinite capacity. For example, in the design of a computer system one of the important problems is how much capacity is required for a buffer memory. It its capacity is too little, then overflow of customers (jobs) occurs frequently in heavy traffic and the performance of system deteriorates rapidly. On the other hand, if its capacity is too large, then most buffer memories remain unused.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.91-98
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• 2001

TCP/IP based remote system using internet presented the method to access and control all the types of resources connected to network system over time and space. In this paper, We studied a resource control method through a mutual communication of a system association composed of service user, provider, and manager of the network system for the web based remote control system. The service users require the resources, and its providers are a variety of devices and digital electronic products which can provide the services in a network system. The service manager who operates the whole system performs the role to interconnect its users with its providers. Through an experiment, an implemented system confirmed flexibility, stability, and extensibility of the method presented in this paper.