• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.115-122
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• 1999

In this paper, we confirmed that a speech signal is a chaos signal, and in order to use it as a speaker recognition parameter, analyzed chaos dimension. In order to raise speaker identification and pattern recognition, by making up the strange attractor involving an individual's vocal tract characteristics very well and applying fuzzy membership function to correlation dimension, we proposed fuzzy correlation dimension. By estimating the correlation of the points making up an attractor are limited according space dimension value, fuzzy correlation dimension absorbed the variation of the reference pattern attractor and test pattern attractor. Concerning fuzzy correlation dimension, by estimating the distance according to the average value of discrimination error per each speaker and reference pattern, investigated the validity of speaker recognition parameter.

• Journal of Information Processing Systems
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• v.11 no.3
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• pp.483-494
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• 2015

High Efficiency Video Coding (HEVC) is the most recent video codec standard of the ITU-T Video Coding Experts Group and the ISO/IEC Moving Picture Experts Group. The main goal of this newly introduced standard is for catering to high-resolution video in low bandwidth environments with a higher compression ratio. This paper provides a performance comparison between HEVC and H.264/AVC video compression standards in terms of objective quality, delay, and complexity in the broadcasting environment. The experimental investigation was carried out using six test sequences in the random access configuration of the HEVC test model (HM), the HEVC reference software. This was also carried out in similar configuration settings of the Joint Scalable Video Module (JSVM), the official scalable H.264/AVC reference implementation, running on a single layer mode. According to the results obtained, the HM achieves more than double the compression ratio compared to that of JSVM and delivers the same video quality at half the bitrate. Yet, the HM encodes two times slower (at most) than JSVM. Hence, it can be concluded that the application scenarios of HM and JSVM should be judiciously selected considering the availability of system resources. For instance, HM is not suitable for low delay applications, but it can be used effectively in low bandwidth environments.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.71-76
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• 2023

Recently, a memory management strategy that utilizes read and write references separately is attracting attention. This is due to the emergence of new storage media with asymmetric read/write latencies and different read/write access characteristics of software. Existing research assumes that operating systems can differentiate between read/write references that occur on each memory page, but most memory architectures do not support a way to distinguish them. Unlike previous studies, this paper proposes a software method that reflects the read/write characteristics of page references by utilizing the reference and modified bits of each page. Simulations show that the proposed policy has almost similar effects to existing studies with hardware support.

• Journal of Navigation and Port Research
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• v.35 no.9
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• pp.701-706
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• 2011

Radio waves including GPS signals, various TV communications, and radio broadcasting can be disturbed by a strong solar storm, which may occur due to solar flares and produce an ionospheric delay anomaly in the ionosphere according to the change of total electron content. Electron density irregularities can cause deep signal fading, frequently known as ionospheric scintillation, which can result in the positioning error using GPS signal. This paper proposes a detection algorithm for the ionosphere delay anomaly during a solar storm by using multi-reference stations. Different TEC grid which has irregular electron density was applied above one reference station. Then the ionospheric delay in zenith direction applied different TEC will show comparatively large ionospheric zenith delay due to the electron irregularity. The ionospheric slant delay applied an elevation angle at reference station was analyzed to detect the ionospheric delay anomaly that can result in positioning error. A simulation test was implemented and a proposed detection algorithm using data logged by four reference stations was applied to detect the ionospheric delay anomaly compared to a criterion.

• Journal of Broadcast Engineering
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• v.19 no.5
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• pp.687-698
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• 2014

ATSC is currently working on standardization of hybrid 3DTV broadcasting service in heterogenous network environment after completion of service-compatible 3DTV broadcasting service standard based on broadcasting channel. This paper proposes a convergence 3D video broadcasting method on broadcasting and IP network while guaranteeing a Full-HD 3D quality without degrading the image quality of legacy DTV. Specifically, this paper describes transmission of the 3D additional video using the ISO/IEC 23009-1 DASH, robust synchronization method under heterogenous network environments and system target decoder model for hybrid 3DTV receiver. Based on experimental results, we confirm that proposed technologies can be used as a core technology in the hybrid 3DTV standardization and a reference model for a development of hybrid 3DTV encoder and receiver.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.109-115
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• 2016

Life log started with the simple purpose of recording or sharing mainly data regarding one's personal life, but with the introduction of advanced specialized analytic methods by many corporations, a new type of business based on the life log recently emerged, with an aim of improving the quality of people's personal lives. In spite of the indispensable advantages, however, personal health lifelog service brings critical challenges that cannot be avoided from user side if the security of the data is concerned. The problem of user's privacy infringement and leaking user's sensitive medical information is increasing with the revitalization of personal health lifelog services. In this paper, we propose an information security reference model for the personal health lifelog services. Our proposal can contribute to increase the related industry to cultivate new market by suggesting the clear announcement of the guidelines using privacy protection reference model for user-specific healthcare services which uses personal lifelog.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.1-6
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• 2012

In this paper, the performance comparison of the TR-UWB System using Wavelet Pulse, DPSS pulse, and second Gaussian pulse in multi-user environment is analyzed. The data signal and the reference signal is sent with some time intervals in TR-UWB system. At this time the two signals are through the same channel. In the receiver the reference signal is used as a template. This advantage results in demodulation without channel estimation and low complexity of it. However the conventional TR-UWB system based on a Gaussian signal in a multi-user environment has the disadvantage of poor performance due to the interferences between the users. To overcome this disadvantage, DPSS (Discrete Prolate Shperoidal Sequence) is used to reduce the interferences between the users. We propose the system with multiresolution function of orthogonal wavelet reducing the interferences, which has a better performance in multi-user environment when they are sent in transmission side.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.1-10
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• 2007

This paper describes the development of a network-based passenger information system(PIS) which provides the convenience of the passenger of the train and heightens the effect of the subtitle service, the advertising and the shelter guidance broadcasting against the urgent event. The existing system uses VGA signal distributor in order to broadcast information with image and subtitle and voice guidance. In this paper we improve the existing system by applying the UDP and TCP/IP protocol and use a reference clock to solve a data loss and synchronization problem which occurs in this case. We also developed an XML-based subtitle authoring tool which can edit and play the subtitles with various 3D to improve the automatic guidance broadcasting and advertisement effect according to the operation schedule of the train. The system performance was evaluated through a simulation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.65-70
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• 2021

Recently, as the number of mobile apps rapidly increases, the memory size of smartphones keeps increasing. Smartphone memory consists of DRAM and as it is a volatile medium, continuous refresh operations for all cells should be performed to maintain the contents. Thus, the power consumption of memory increases in proportion to the DRAM size of the system. There are attempts to configure the memory system with low-power non-volatile memory instead of DRAM to reduce the power consumption of smartphones. However, non-volatile memory has weaknesses in write operations, so analysis of write behaviors is a prerequisite to realize this in practical systems. In this paper, we extract memory reference traces of mobile apps and analyze their characteristics specially focusing on write operations. The results of this paper will be helpful in the design of memory management systems consisting of non-volatile memory in future smartphones.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.1
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• pp.31-36
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• 2024

Recently, mobile apps that utilize AI technologies are increasing. In the personal mobile environment, performance degradation may occur during the training phase of large AI workload due to limitations in memory capacity. In this paper, we extract memory reference traces of AI workloads and analyze their characteristics. From this analysis, we observe that AI workloads can cause frequent storage access due to weak temporal locality and irregular popularity bias during memory write operations, which can degrade the performance of mobile devices. Based on this observation, we discuss ways to efficiently manage memory write operations of AI workloads using persistent memory-based swap devices. Through simulation experiments, we show that the system architecture proposed in this paper can improve the I/O time of mobile systems by more than 80%.