• Journal of the Korea Institute of Information and Communication Engineering
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• 제13권7호
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• pp.1411-1421
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• 2009

As the wireless internet grows exponentially, the recent trend has an increasing demand for wireless network and multimedia services. RTP is used to support the multimedia communication over the Internet and it supports the flexibility and adaptability over a wide range. However, RTP has a limitation that it cannot support end-to-end QoS guarantee in a wireless home network which has low throughput and high delay. In this paper, we propose the architecture of a real-time multimedia communication and design and implement the hybrid flow control in the architecture. The hybrid flow control mechanism is based on modified AIMD using metrics such as the network state information and the user properties. We implement the porposed flow control using JMF to evaluate the performance of the proposed flow control. The experimental results show that the proposed flow control has better performance than the AIMD.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제21권8호
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• pp.1498-1507
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• 2017

According to recent report, global mobile data traffic is expected to increase by 11 times from 2016 to 2020. Moreover, this growth is expected to be driven mainly by mobile video traffic which is expected to account for about 70% of the total mobile data traffic. To cope with enormous mobile traffic, we need to understand video traffic's characteristic. Recently, the repetitive requests of some popular content such as popular YouTube videos cause a enormous network traffic overheads. If we constitute a network with the nodes capable of content caching based on the content popularity, we can reduce the network overheads by using the cached content for every request. Through device-to-device, multicast, and helpers, the video throughput can improve about 1.5~2 times and prefix caching reduces the playback delay by about 0.2~0.5 times than the conventional method. In this paper, we introduce some recent work on content popularity-based caching techniques in wireless networks.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제10권8호
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• pp.1998-2004
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• 2009

Recently, due to technical developments of various storage devices and networks, the amount of data increases rapidly. The large volume of data streams poses unique space and time constraints on the data mining process. The continuous characteristic of streaming data necessitates the use of algorithms that require only one scan over the stream for knowledge discovery. Most of the researches based on the support are concerned with the frequent itemsets, but ignore the infrequent itemsets even if it is crucial. In this paper, we propose an efficient method WSFI-Mine(Weighted Support Frequent Itemsets Mine) to mine all frequent itemsets by one scan from the data stream. This method can discover the closed frequent itemsets using DCT(Data Stream Closed Pattern Tree). We compare the performance of our algorithm with DSM-FI and THUI-Mine, under different minimum supports. As results show that WSFI-Mine not only run significant faster, but also consume less memory.

• Journal of Korea Multimedia Society
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• 제11권7호
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• pp.977-985
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• 2008

This paper is concerned with automatic telemetering system which reads the consumed quantity of electricity, gas, and piped water. The existing metering method such that a meterman visits households and directly reads meters can cause several problems, including violation of privacy and the possibility of criminal accident, as well the inefficiency in viewpoint of system operation and rate notification. In this paper, we propose a new automatic telemetering and rate notification system, in which the system reads several meters at remote locations and notifies the rates to the customer's cellular phone with short message service(SMS). The proposed system has been developed by using CDMA mobile communication modules and personal computers. This system can operate only with cellular communication network even without wired-internet facilities. In particular, the developed system can provide home security and convenience as well as cost reduction, and thus be applied to intelligent home networks.

• The Journal of the Korea institute of electronic communication sciences
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• 제14권5호
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• pp.927-934
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• 2019

Recently, mobile devices have evolved into small computers with various functions according to user requirements. Careful attention must be paid to the design of the power supply network for the stable operation of the application processor (AP), the wireless communication modem, the high performance camera, and the various interfaces of the mobile device to implement various functions of the mobile device. In this paper, we analyzed and verified the method of optimizing the design parameters such as the position, capacity, and number of decoupling capacitors to meet the target impedance required by the driver IC chip to ensure the stability of the power supply network of mobile devices that should be designed as wiring type due to mounting density limitation. The proposed wired power supply network design method can be applied to various applications including high-speed signal transmission line in addition to mobile applications.

• The Journal of the Acoustical Society of Korea
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• 제40권5호
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• pp.466-472
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• 2021

Speaker Change Detection (SCD) refers to finding the moment when the main speaker changes from one person to the next in a speech conversation. In speaker change detection, difficulties arise due to overlapping speakers, inaccuracy in the information labeling, and data imbalance. To solve these problems, TIMIT corpus widely used in speech recognition have been concatenated artificially to obtain a sufficient amount of training data, and the detection of changing speaker has performed after identifying overlapping speakers. In this paper, we propose an speaker change detection system that considers the speaker overlapping. We evaluated and verified the performance using various approaches. As a result, a detection system similar to the X-Vector structure was proposed to remove the speaker overlapping region, while the Bi-LSTM method was selected to model the speaker change system. The experimental results show a relative performance improvement of 4.6 % and 13.8 % respectively, compared to the baseline system. Additionally, we determined that a robust speaker change detection system can be built by conducting related studies based on the experimental results, taking into consideration text and speaker information.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제28권6호
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• pp.1309-1317
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• 2018

Although the IoT market is steadily growing, there is still a lack of consideration for increasing security threats in the IoT environment. In particular, it is difficult to apply existing IP security technology to resource-constrained devices. Therefore, there is a demand for reliable end-to-end communication security measures to cope with security threats such as information tampering and leakage that may occur during communication between heterogeneous networks do. In this paper, we propose an end-to-end message security protocol based on lightweight cipher that increases security and lowers security overhead in resource-constrained IoT device communication. Through simulation of processing time, we verified that the proposed protocol has better performance than the existing AES-based protocol.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.672-674
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• 2014

Mobile communication technology was one of the GPS technology, SmartPhone, Tablet PC is equipped with a GPS. So the user has a navigation, speed and his position to send and receive a variety of information. Therefore, in this paper, Mobile devices, GPS, Wi-Fi and mobile networks, and the communication module uses algorithms to analysis of acceleration and output, the user is currently using the system to find out the kind of transportation. This is the users who are using a particular transport unnecessary information and apply it to different areas do not think I will be able to.

• Journal of Contemporary Eastern Asia
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• 제18권1호
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• pp.49-69
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• 2019

Over the last couple of years, digital diplomacy has become a fascinating area of research among Mass Communication, Peace and Conflict Studies, and International Affairs scholars. Social media and new technology open up new avenues for governments, individuals, and organizations to engage with foreign audiences. However, developing countries' governments are still lacking in the realization of the potential of social media. This study aims to analyze the usage of social media (Facebook & Twitter) by the two biggest countries in South Asia (Pakistan and India). I selected 10 government officials' social media accounts including prime ministers', national press offices', military public relations offices', public diplomacy divisions', and ministries of foreign offices' profiles. The study relies on quantitative content analysis and a comparative research approach. The total number of analyzed Twitter tweets (n=1,015) and Facebook posts (n=1,005) include 10 accounts, five from each country. In light of Kent and Taylor's (1998) dialogic communication framework, the results indicate that no digital engagement and dialogue occurs between government departments and the public through social networking sites. Government departments do not engage with local or foreign audiences through digital media. When comparing both countries, results reveal that India has more institutionalized and organized digital diplomacy. In terms of departmental use of social media, the digital diplomacy division and foreign office of India is more active than other government departments in that nation. Meanwhile, Pakistan's military public relations office and press office is more active than its other government departments. In conclusion, both countries realize the potential of social media in digital diplomacy, but still lack engagement with foreign audiences.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제23권8호
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• pp.1004-1010
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• 2019

In the EH-WSN (Energy harvesting wireless sensor network), a MAC (medium access control) protocol is required to select a relay node considering the power status of a node. Existing EH-WSN studies emphasize the power aspect, so it does not consider the QoS like the urgency of the sensed data. The required power and transmission delay must be changed according to the urgency so that the medium access control according to the data QoS can be performed. In case of relay node, relaying data without consideration of data urgency and node power may cause delay due to power shortage in case of urgent data. In this paper, we designed a MAC protocol that minimizes the power shortage that can occur during emergency data generation. For this, relay node requirements are set differently according to the urgency of data. The performance was analyzed through simulation. Simulation results show the reduced latency and improved reliability of urgent data transmission.