• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.903-906
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• 1987

The digital private line network provides synchronous data communications over dedicated facilities at several speeds. This service became available to several major metropolitan areas in 1986 with speeds of 4800, 9600, 56000 b/s. The network is expected to grow to include many city areas. In this paper, synchronization plan for the network is proposed.

• Journal of the Korea Safety Management & Science
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• v.3 no.1
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• pp.107-116
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• 2001

ISO 9000 has brought about significant positive effects to the quality management system and quality improvement. This paper develops effective and flexible ISO 9000 quality system based on telecommunication manufactured goods with CSU(Channel Service Unit), ADSL(Asymmetric Digital Subscriber Line), Fiber Optic Multiplexer, HDSL(High-bit-rate Digital Subscriber Line), FDSU(Flexible Data Service Unit), 73 DSU(Digital Service Unit). The case studies of venture telecommunication corporation in establishing ISO 9000 qualify system are also discussed.

• Asia pacific journal of information systems
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• v.12 no.1
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• pp.139-158
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• 2002

As the telecommunication market becomes mature in Korea, severe competition has already begun on the market. While service providers struggled for the last couple of years to acquire as many new customers as possible, nowadays they are making more efforts on retaining the current customers. The churn management by analyzing customers' demographic and transactional data becomes one of the key customer retention strategies which most companies pursue. However, the customer data analysis has still remained at the basic level in the industry, even though it has considerable potential as a tool for understanding customer behavior. This paper develops several churn prediction models using data mining techniques such as logistic regression, decision trees, and neural networks. For model-building, real data were used which were collected from one of the major telecommunication companies in Korea. This paper explores various ways of comparing model performance, while the hit ratio was mainly focused in the previous research. The comparison criteria used in this study include gain ratio, Kolmogorov-Smirnov statistics, distribution of the predicted values, and explanation ability. This paper also suggest some guidance for model selection in applying data mining techniques.

• International Journal of Advanced Culture Technology
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• v.10 no.1
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• pp.310-316
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• 2022

The smart tourism service provides services such as travel planning and tour guides to tourists using key technologies of the 4th industrial revolution, such as the Internet of Things, communication infrastructure, big data, artificial intelligence, AR/VR, and drones. We are developing smart tourism services such as recommended travel products, my travel itinerary, tourism information, and chatbots for tourists through the smart tourism app. In this paper, we develop a smart tourism service system that provides real-time location-based tourism information and weather information to tourists. The smart tourism service system consists of a smart tourism app, a smart tourism information system, and an IoT data collection device. The smart tourism information system receives weather information from the IoT data collection device installed in the tourist destination. The location-based smart tourism service is provided as a smart tourism app in the smart tourism information system according to the Beacon's UUID in the IoT data collection device. The smart tourism information system stores the Beacon's UUIDs received from tourists and provides a safe hiking service for tourists.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10a
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• pp.17-18
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• 2007

• Journal of Information Technology Services
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• v.8 no.2
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• pp.229-245
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• 2009

The Korean mobile telecommunication service market is faced with a tremendous competitive period, in which the market is entering into the maturity stage with launching of the 3rd generation service and with introduction of mobile number portability. In general, it is more important to sustain the old customers than to attracting new customers, as the life cycle of an industry is entering the maturity stage in which the growth rate of new customers is decreasing gradually or becoming stagnant. Thus, mobile telecommunication business has to seek a way to maintain the existing customers instead of promoting new customers. So this study investigates whether the service quality of mobile telecommunication could have effects on the switching barrier of the industry. In order to test the hypothesis on the effects of service quality of mobile telecommunication in Korea on switching barrier, this study collected the questionnaire response data of students including middle and high school students and undergraduates, who are regarded as the major customers in that mobile telecommunication industry.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.377-383
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• 2003

As the high-speed data communications such as xDSL using the existing copper cable come into wide use, the electromagnetic coupling characteristics of telecommunication cables become more significant. In order to describe the screening performance of telecommunication cable, the transfer impedance of cable shield is required. This paper describes the transfer impedance for two types of telecommunication cables using the line injection method of IEC 96-1. Results are analyzed to show how the materials of cable shields, the positioning of the injection line and of the inner conductor of the CUT(Cable Under Test) affect the value of transfer impedance. We then propose the transfer impedance model of telecommunication cable based on the measurements.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.2
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• pp.810-831
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• 2019

Recently, continuous dimensional emotion recognition from audiovisual clues has attracted increasing attention in both theory and in practice. The large amount of data involved in the recognition processing decreases the efficiency of most bimodal information fusion algorithms. A novel algorithm, namely the incomplete Cholesky decomposition based kernel cross factor analysis (ICDKCFA), is presented and employed for continuous dimensional audiovisual emotion recognition, in this paper. After the ICDKCFA feature transformation, two basic fusion strategies, namely feature-level fusion and decision-level fusion, are explored to combine the transformed visual and audio features for emotion recognition. Finally, extensive experiments are conducted to evaluate the ICDKCFA approach on the AVEC 2016 Multimodal Affect Recognition Sub-Challenge dataset. The experimental results show that the ICDKCFA method has a higher speed than the original kernel cross factor analysis with the comparable performance. Moreover, the ICDKCFA method achieves a better performance than other common information fusion methods, such as the Canonical correlation analysis, kernel canonical correlation analysis and cross-modal factor analysis based fusion methods.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.3
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• pp.116-121
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• 2009

A novel method for improving the reliability of sensing data using multi-sensors in wireless sensor network systems is presented in this paper. This method is successfully applied a fog monitoring system in the mountain area.

• Journal of electromagnetic engineering and science
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• v.8 no.4
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• pp.148-152
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• 2008

This paper describes the characteristics of lightning-induced voltages on subscriber telecommunication lines in Korea. Lightning parameters such as peak voltage, rise time, decay time, and steepness of the wave front were statistically analyzed from the measured results obtained using a waveform memory system. An induced voltage measurement system was also developed and installed at 286 sites in Korea to collect the induced voltage data. The distributions of lightning-induced voltages were also analyzed using these data.