• Title/Summary/Keyword: Voice Network

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Priority Collision Resolution Algorithm on HFC Networks (우선 순위를 고려한 HFC 망의 충돌 해소 알고리즘)

  • 김변곤;박준성;정경택;전병실
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.7B
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    • pp.1252-1260
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    • 1999
  • The HFC network has a architecture of a star topology in fiber optic trunks, and tree and branch topology is used in the part of coaxial cable. It is well known that the HFC upstream channel is noisy. Ingress, common mode distortion and impulse noise exist in the upstream channel. In order to provide Quality of Service(QoS) to users with real-time data such as voice, video and interactive services, the evolving IEEE 802.14 standard for HFC networks must include an effective priority scheme. The scheme separates and resolves collisions between stations in a priority order. It is important to simulate protocols under a practical environment. The proposed algorithm in this paper is simulated with the assumption that the collision detector made certain mistake due to noises. Simulation results show that the proposed algorithm is more efficient than existing tree-based algorithm under practical environment.

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A Study on the Efficient Power Consumption of Next Generation Mobile Communication Systems (차세대 이동통신 시스템의 효율적인 전력 소모에 관한 연구)

  • Roh, Jae-Sung;Kim, Wan-Tae
    • Journal of Advanced Navigation Technology
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    • v.17 no.1
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    • pp.56-62
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    • 2013
  • Recently with smart phones and tablets, next generation mobile communication systems have supported various multimedia contents services. Thus, multimedia communication systems have been gradually increased compared to voice communication systems. Since the growth of multimedia services has increased users' duration on systems and decreased systems' effectiveness on power, a study on effective usage of power needs to be researched. Furthermore, radio shadow areas under heavy urban environments have generated unnecessary power consumption which reduces the usage duration of power on next generation mobile communication systems. This paper has reviewed the communication network architecture on next generation mobile communication systems and the unnecessary power consumption in radio shadow areas. This paper has also proposed the method of the effective power usage and analyzed the effective power usage on next generation mobile communication systems with simulation.

A Study of Wired and wireless VoIP vulnerability analysis and hacking attacks and security (유무선 VoIP 취약점 분석과 해킹공격 및 보안 연구)

  • Kwon, Se-Hwan;Park, Dea-Woo
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.4
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    • pp.737-744
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    • 2012
  • Recently VoIP has provided voice(both wired and wireless from IP-based) as well as the transmission of multimedia information. VoIP used All-IP type, Gateway type, mVoIP etc. Wired and wireless VoIP has security vulnerabilities that VoIP call control signals, illegal eavesdropping, service misuse attacks, denial of service attack, as well as wireless vulnerabilities etc. from WiFi Zone. Therefore, the analysis of security vulnerabilities in wired and wireless VoIP and hacking incidents on security measures for research and study is needed. In this paper, VoIP (All-IP type, and for Gateway type) for system and network scanning, and, IP Phone to get the information and analysis of the vulnerability. All-IP type and Gateway type discovered about the vulnerability of VoIP hacking attacks (Denial of Service attacks, VoIP spam attacks) is carried out. And that is a real VoIP system installed and operated in the field of security measures through research and analysis is proposed.

Resource Allocation and Control System for VoIP QoS Provision in Cognitive Radio Networks (인지 무선네트워크에서 VoIP QoS 보장을 위한 자원 할당 및 제어 시스템)

  • Kim, Bosung;Lee, Gyu-Min;Roh, Byeong-Hee;Choi, Geunkyung;Oh, Ilhyuk
    • KIISE Transactions on Computing Practices
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    • v.20 no.12
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    • pp.688-693
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    • 2014
  • With the advent of ubiquitous environments, the smart phone has come into wide use and the demand for various content increases. Thus, in order to efficiently utilize limited resources cognitive radio technology is regarded as a possible solution. Besides spectrum sensing or access schemes, the provision of VoIP traffic service for secondary users with limited spectrum resources is a very important issue. In this paper, a resource allocation and control system for VoIP QoS provision in cognitive radio networks is proposed. Firstly, as the system model, the time structure of the network is addressed and, according to the structure, a bandwidth broker is proposed. In addition, based on available bandwidth estimated by the bandwidth broker, a connection admission control for secondary users is developed. It is demonstrated that the provision of VoIP QoS is greatly affected by channel utilization, the number of channels, and the length of timeslot.

Efficient Processing of Multidimensional Sensor stream Data in Digital Marine Vessel (디지털 선박 내 다차원 센서 스트림 데이터의 효율적인 처리)

  • Song, Byoung-Ho;Park, Kyung-Woo;Lee, Jin-Seok;Lee, Keong-Hyo;Jung, Min-A;Lee, Sung-Ro
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.5B
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    • pp.794-800
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    • 2010
  • It is necessary to accurate and efficient management for measured digital data from various sensors in digital marine vessel. It is not efficient that sensor network process input stream data of mass storage stored in database the same time. In this paper, We propose to improve the processing performance of multidimensional stream data continuous incoming from multiple sensor. We propose that we arrange some sensors (temperature, humidity, lighting, voice) and process query based on sliding window for efficient input stream and found multiple query plan to Mjoin method and we reduce stored data using SVM algorithm. We automatically delete that it isn't necessary to the data from the database and we used to ship diagnosis system for available data. As a result, we obtained to efficient result about 18.3% reduction rate of database using 35,912 data sets.

Speech Animation with Multilevel Control (다중 제어 레벨을 갖는 입모양 중심의 표정 생성)

  • Moon, Bo-Hee;Lee, Son-Ou;Wohn, Kwang-yun
    • Korean Journal of Cognitive Science
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    • v.6 no.2
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    • pp.47-79
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    • 1995
  • Since the early age of computer graphics, facial animation has been applied to various fields, and nowadays it has found several novel applications such as virtual reality(for representing virtual agents), teleconference, and man-machine interface.When we want to apply facial animation to the system with multiple participants connected via network, it is hard to animate facial expression as we desire in real-time because of the size of information to maintain an efficient communication.This paper's major contribution is to adapt 'Level-of-Detail'to the facial animation in order to solve the above problem.Level-of-Detail has been studied in the field of computer graphics to reperesent the appearance of complicated objects in efficient and adaptive way, but until now no attempt has mode in the field of facial animation. In this paper, we present a systematic scheme which enables this kind of adaptive control using Level-of-Detail.The implemented system can generate speech synchronized facial expressions with various types of user input such as text, voice, GUI, head motion, etc.

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An Analysis on Data Throughput of PicoCast Affected by Piconet Mutual Interference (피코넷 상호 간섭이 PicoCast 데이터 전송량에 미치는 영향 분석)

  • Chung, Jae-Kyong;Jeon, Sang-Yeop;Kim, Myoung Jin
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.2
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    • pp.40-49
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    • 2015
  • PicoCast is a recently proposed short-range wireless communications technology that supports both low rate sensor/control data and high speed data such as voice and video traffic in the personal space, defined by the user-centric space of radius tens of meters, with one unified protocol. When the users are in the same area, personal spaces defined by each user may overlap. Since these PicoCast piconets may simultaneously operate, mutual interference is unavoidable. It is necessary to investigate the effect of mutual interference on data transmission and to conduct research on minimizing the interference among PicoCast devices. In this paper we analyze the effect of mutual interference between PicoCast piconets based on data throughput using OPNET network simulator. We have implemented the PicoCast protocol and measured the average throughput and packet loss rate.

A Study for the MPEG-4 Library to operate in real-time on the DSP (DSP상에서 실시간 처리 가능한 MPEG-4 Library에 관한 연구)

  • Hong, Sung-Hwa;Jung, Suk-Yong
    • Journal of the Korea Convergence Society
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    • v.2 no.1
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    • pp.7-13
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    • 2011
  • Informations of multimedia centering in the images, are combined acoustic and letter, etc. Although the network advances and the capacity of the storage media extends, these huge informations will not be able to accommodate. From meaning which is like this, International standards for the compression and a multiplexing of image, acoustic and voice H261 where admits standard, JPEG, JBIG, MPEG-l, MPEG-2, MPEG-4 and H263, G series etc, are core techniques of multimedia. At initial step of the base technique which creates the base of like this multimedia service time, we developed the real-time MPEG-4 transmission systems to provides real-time MPEG-4 multimedia services. This system means becomes the base technique which hereafter is developed and is applied various system. This system Will be able to apply from a videoconference, a building protection system and a VOD video system to use the Internet. And, They, the image sensing, embedded linux, and MPEG4 software, will become sourceful technique to develop the different system.

A study on Iris Recognition using Wavelet Transformation and Nonlinear Function

  • Hur, Jung-Youn;Truong, Le Xuan
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2004.10a
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    • pp.553-559
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    • 2004
  • In todays security industry, personal identification is also based on biometric. Biometric identification is performed basing on the measurement and comparison of physiological and behavioral characteristics, Biometric for recognition includes voice dynamics, signature dynamics, hand geometry, fingerprint, iris, etc. Iris can serve as a kind of living passport or living password. Iris recognition system is the one of the most reliable biometrics recognition system. This is applied to client/server system such as the electronic commerce and electronic banking from stand-alone system or networks, ATMs, etc. A new algorithm using nonlinear function in recognition process is proposed in this paper. An algorithm is proposed to determine the localized iris from the iris image received from iris input camera in client. For the first step, the algorithm determines the center of pupil. For the second step, the algorithm determines the outer boundary of the iris and the pupillary boundary. The localized iris area is transform into polar coordinates. After performing three times Wavelet transformation, normalization was done using sigmoid function. The converting binary process performs normalized value of pixel from 0 to 255 to be binary value, and then the converting binary process is compare pairs of two adjacent pixels. The binary code of the iris is transmitted to the by server. the network. In the server, the comparing process compares the binary value of presented iris to the reference value in the University database. Process of recognition or rejection is dependent on the value of Hamming Distance. After matching the binary value of presented iris with the database stored in the server, the result is transmitted to the client.

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Predictive Traffic Control Scheme of ABR Service (ABR 서비스를 위한 예측 트래픽 제어모델)

  • 오창윤;임동주;배상현
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.2
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    • pp.307-312
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    • 2000
  • Asynchronous transfer mode(ATM) is flexible to support the various multimedia communication services such as data, voice, and image by applying asynchronous time-sharing and statistical multiplexing techniques to the existing data communication. ATM service is categorized to CBR, VBR, UBR, and ABR according to characteristics of the traffic and a required service qualities. Among them, ABR service guarantees a minimal bandwidth and can transmit cells at a maximum transmission rate within the available bandwidth. To minimize the cell losses in transmission and switching, a feedback information in ATM network is used to control the traffic. In this paper, predictive control algorithms are proposed for the feedback information. When the feedback information takes a long propagation delay to the backward nodes, ATM switch can experience a congestion situation from the queue length increases, and a high queue length fluctuations in time. The control algorithms proposed in this paper provides predictive control model using slop changes of the queue length function and previous data of the queue lengths. Simulation shows the effectiveness result of the proposed control algorithms.

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