• Title/Summary/Keyword: Multimedia devices

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Measurement of 18GHz Radio Propagation Characteristics in Subway Tunnel for Train-Wayside Multimedia Transmission (지하철 터널에서의 18GHz 무선영상신호 전파특성 측정)

  • Choi, Kyu-Hyoung;Seo, Myung-Sik
    • Journal of the Korean Society for Railway
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    • v.15 no.4
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    • pp.364-369
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    • 2012
  • This paper presents an experimental study on the radio propagation characteristics in subway tunnel at 18GHz frequency band which has been assigned to video transmission between train and wayside. The radio propagation tests are carried out in the subway tunnel of Seoul Metro using the antenna and communication devices of the prototype video transmission system. The measurement results show that 18GHz radio propagation in subway tunnel has smaller path loss than that of general outdoor radio environment. It is also cleared that the arch-type tunnels have smaller radio propagation losses than rectangular tunnels, and single track tunnels have smaller pass loss than double track tunnels. From the measurements, the radio propagation coverage is worked out as 520 meters. The curved tunnels which cannot have LOS communication between transmitter and receiver have large pass losses and fluctuation profile along distance. The radio propagation coverage along curved tunnels is worked out as 300 meters. These investigation results can be used to design the 18GHz radio transmission system for subway tunnel by providing the optimized wayside transmitter locations and handover algorithm customized to the radio propagation characteristics in subway tunnels.

3D Physical User Interface System using a Dominant Eye and an Index Fingertip (주시안과 검지 끝 점을 이용한 3차원 물리 사용자 인터페이스 시스템)

  • Kim, Kyung-Ho;Ahn, Jeeyun;Lee, Jongbae;Kwon, Heeyong
    • Journal of Korea Multimedia Society
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    • v.16 no.2
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    • pp.138-146
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    • 2013
  • In this paper, we propose a new 3D PUI(Physical User Interface) system in which the index fingertip points and moves a mouse position on a given monitor screen. There are two 3D PUI schemes to control smart devices like smart TVs remotely, the relative pointing one and the absolute pointing one. The former has a problem in that it does not match the human perception process, and the latter requires excessive movement of the body. We combined the relative one and the absolute one, and develop a new intuitive and user-friendly pointing method, 3D PUI. It requires an establishment of a pyramid shape visible area (view volume) to point a mouse position on a screen with the dominant eye. In order to maintain the real-time view volume, however, it requires large computation depending on the movement of the dominant eye. We optimized the computation of the view volume in which it determines the internal and external position on the screen. In addition, Kalman filter is applied with tracing of the mouse pointer position to stabilize the trembling of the pointer and offers the user ease of use.

A Framework of N-Screen Session Manager based N-Screen Service using Cloud Computing in Thin-Client Environment (씬클라이언트 환경에서 클라우드 컴퓨팅을 이용한 N-Screen 세션 관리 기반의 N-Screen 서비스 프레임워크)

  • Alsaffar, Aymen Abdullah;Song, Biao;Hassan, Mohammad Mehedi;Huh, Eui-Nam
    • Journal of Internet Computing and Services
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    • v.13 no.2
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    • pp.21-32
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    • 2012
  • We develop architecture of a virtual aggregation gateway (VAG) which enables composite application streaming based on N-Screen-as-a-Service (NaaS) using cloud computing in thin-client environment. We also discuss the problem of server computing burden in large scale multi-client case for screens sharing with composite application streaming over the internet. In particular, we propose an efficient Framework of N-Screen Session Manager which manages all media signaling that are necessary to deliver demanded contents. Furthermore, it will provides user with playback multimedia contents method (TV Drama, Ads, and Dialog etc) which is not considered in other research papers. The objectives of proposing N-Screen Session Manager are to (1) manage session status of all communication sessions (2) manage handling of received request and replies (3) allow users to playback multimedia contents anytime with variety of devices for screen sharing and (4) allow users to transfer an ongoing communication session from one device to another. Furthermore, we discuss the major security issues that occur in Session Initiation Protocol as well as minimizing delay resulted from session initiations (playback or transfer session).

Audio Quality Enhancement at a Low-bit Rate Perceptual Audio Coding (저비트율로 압축된 오디오의 음질 개선 방법)

  • 서정일;서진수;홍진우;강경옥
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.6
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    • pp.566-575
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    • 2002
  • Low-titrate audio coding enables a number of Internet and mobile multimedia streaming service more efficiently. For the help of next-generation mobile telephone technologies and digital audio/video compression algorithm, we can enjoy the real-time multimedia contents on our mobile devices (cellular phone, PDA notebook, etc). But the limited available bandwidth of mobile communication network prohibits transmitting high-qualify AV contents. In addition, most bandwidth is assigned to transmit video contents. In this paper, we design a novel and simple method for reproducing high frequency components. The spectrum of high frequency components, which are lost by down-sampling, are modeled by the energy rate with low frequency band in Bark scale, and these values are multiplexed with conventional coded bitstream. At the decoder side, the high frequency components are reconstructed by duplicating with low frequency band spectrum at a rate of decoded energy rates. As a result of segmental SNR and MOS test, we convinced that our proposed method enhances the subjective sound quality only 10%∼20% additional bits. In addition, this proposed method can apply all kinds of frequency domain audio compression algorithms, such as MPEG-1/2, AAC, AC-3, and etc.

Intelligent Tutoring System based on Wired and Wireless Internet for the living English 300-certifications Program (생활영어 300 인증제를 대비한 유무선 기반 지능형 교육 시스템)

  • Lee, Young-Seok;Cho, Jung-Won;Kim, Byung-Gyu;Park, Jung-Hwan;Kim, Su-Min;Choi, Byung-Uk
    • Journal of The Korean Association of Information Education
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    • v.9 no.3
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    • pp.533-548
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    • 2005
  • According to the increasing of the internet infrastructure and growth of contents technology, the users can access an education service at anytime and anywhere. In a field of English education, especially, internet technology has enabled learners to communicate with their teachers and multimedia contents technology has been able to provide learner not only lots of interests, but also good effect on English learning. In this paper, we propose a method diagnosing learner's level by using some question-items, which consist of item's type and item's function. Futhermore, the proposed system can support three devices which are PC, PDA, and Mobile Phone on wired and wireless internet communication environments. Also, the system provides multimedia contents including flash movies, image, and audio contents. We have applied the system into real classroom, and we verified that the question-items that system provides has no problem, and our method could improve each learner skill on English education. Therefore, we expect that learner who uses the proposed system will get level-based English learning service at anytime and anywhere.

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An Energy-Efficient and Destination-Sequenced Routing Algorithm by a Sink Node in Wireless Sensor Networks (무선 센서 네트워크에서의 싱크 노드에 의한 에너지 효율적인 목적지-순서적 라우팅 알고리즘)

  • Jung, Sang-Joon;Chung, Youn-Ky
    • Journal of Korea Multimedia Society
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    • v.10 no.10
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    • pp.1347-1355
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    • 2007
  • A sensor network is composed of a large number of tiny devices, scattered and deployed in a specified regions. Each sensing device has processing and wireless communication capabilities, which enable it to gather information from the sensing area and to transfer report messages to a base station. The energy-efficient routing paths are established when the base station requests a query, since each node has several characteristics such as low-power, constrained energy, and limited capacity. The established paths are recovered while minimizing the total transmit energy and maximizing the network lifetime when the paths are broken. In this paper, we propose a routing algorithm that each sensor node reports its adjacent link information to the sink node when a sink node broadcasts a query. The sink node manages the total topology and establishes routing paths. This algorithm has a benefit to find an alternative path by reducing the negotiating messages for establishing paths when the established paths are broken. To reduce the overhead of collection information, each node has a link information before reporting to the sink. Because the node recognizes which nodes are adjacent. The proposed algorithm reduces the number of required messages, because sensor nodes receive and report routing messages for establishment at the beginning of configuring routing paths, since each node keeps topology information to establish a routing path, which is useful to report sensing tasks in monitoring environments.

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Contactless Fingerprint Recognition Based on LDP (LDP 기반 비접촉식 지문 인식)

  • Kang, Byung-Jun;Park, Kang-Ryoung;Yoo, Jang-Hee;Moon, Ki-Young;Kim, Jeong-Nyeo;Shin, Jae-Ho
    • Journal of Korea Multimedia Society
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    • v.13 no.9
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    • pp.1337-1347
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    • 2010
  • Fingerprint recognition is a biometric technology to identify individual by using fingerprint features such ridges and valleys. Most fingerprint systems perform the recognition based on minutiae points after acquiring a fingerprint image from contact type sensor. They have an advantage of acquiring a clear image of uniform size by touching finger on the sensor. However, they have the problems of the image quality can be reduced in case of severely dry or wet finger due to the variations of touching pressure and latent fingerprint on the sensor. To solve these problems, the contactless capturing devices for a fingerprint image was introduced in previous works. However, the accuracy of detecting minutiae points and recognition performance are reduced due to the degradation of image quality by the illumination variation. So, this paper proposes a new LDP-based fingerprint recognition method. It can effectively extract fingerprint patterns of iterative ridges and valleys. After producing histograms of the binary codes which are extracted by the LDP method, chi square distance between the enrolled and input feature histograms is calculated. The calculated chi square distance is used as the score of fingerprint recognition. As the experimental results, the EER of the proposed approach is reduced by 0.521% in comparison with that of the previous LBP-based fingerprint recognition approach.

Development of a functional game device and Contents for improving of brain activity through finger exercise (뇌활동 증진을 위한 손가락 운동용 기능성 게임 장치 및 콘텐츠 개발)

  • Ahn, Eun-Young
    • Journal of Korea Multimedia Society
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    • v.15 no.11
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    • pp.1384-1390
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    • 2012
  • It is well known that the exercising and stimulating of fingers have an important bearing on the brain. We take note of the fact and develope a game device for improving one's health and brain ability in respect of the education and training. Especially, we develope the device focused on the balanced exercising of five finger for improving brain function. The game device is possible to used in two-ways, namely online and off-line mode. In online mode, the device is connected with other visual devices such as smart phone and smart TV and communicated with Bluetooth and it is used as a MMI(multi-modal interface) device. Whereas, in off-line mode the game device works independently and it makes possible to enjoy auditorial and tactual games without video images for promotion of brain activity and emotional cultivation. For certification of the device, we implement two games(a fishing game for off-line mode and a shooting game for online mode) for people of all age, especially good for the elderly. It is usable as a game device to offering the elderly a great help for preventing impairment of the cognitive functions.

A Normalization Method to Utilize Brain Waves as Brain Computer Interface Game Control (뇌파를 BCI 게임 제어에 활용하기 위한 정규화 방법)

  • Sung, Yun-Sick;Cho, Kyung-Eun;Um, Ky-Hyun
    • Journal of Korea Game Society
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    • v.10 no.6
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    • pp.115-124
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    • 2010
  • In the beginning brain waves were used for monkeys to control robot arm with neural activity. In recent years there are research that measured brain waves are used for the control of programs which monitor the progression of dementia or enhance of attention in children diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). Moreover, low-price devices that can be used as a game control interface have become available. One of the problems associated with control using brain waves is that the mean amplitude, mean wavelength, and mean vibrational frequency of the brain waves differ from individual to individual. This paper attempts to propose a method to normalize measured brain waves using normal distribution and calculate the waveforms that can be used in controlling games. For this, a framework in which brain waves are converted in seven stages has been suggested. In addition, the estimation process in each stage has been described. In an experiment the waveforms of two subjects have been compared using the proposed method in the BCI English word learning program. The level of similarity between two subjects' waveforms has been compared with correlation coefficient. When the proposed method was applied, both meditation and concentration increased by 13% and 8%, respectively. Because the proposed regularization method is converted into a waveform fit for control functions by reducing personal characteristics reflected in the brain waves, it is fitting for application programs such as games.

Software Architecture of IEEE1394 Based Home Network for Guaranteeing Real-Time Characteristics of Isochronous Service and Event (IEEE1394 기반의 홈 네트웍에서 이벤트와 등시성 서비스의 실시간성 보장을 위한 소프트웨어 구조)

  • Park, Dong-Hwan;O, Bong-Jin;Gang, Sun-Ju
    • The KIPS Transactions:PartA
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    • v.9A no.2
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    • pp.181-190
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    • 2002
  • IEEE1394 is a de facto standard for the home network interfaces of digital multimedia home devices including digital A/V systems, digital camcorders, and PCs. Recently, it has been used in applications to guarantee the real-time characteristics such as home automation system and IICP (Instrument and Industrial Control Protocol). In order to guarantee real-time requirements in these IEEE1394-based real-time applications, this thesis proposes the software architecture of an IEEE1394 based home network that supports the guarantee for service's react-time characteristics. The proposed architecture has a real-time IEEE1394 device driver and event service architecture for guarantee real-time characteristics. The real-time device driver supports priority-based queueing of packets and mechanism to reduce the interrupt latency time in ISR. The event service architecture supports a real-time events delivery based on home network service using real-time event channel. This architecture can accommodate the real-time requirements of various applications and services such as digital multimedia services with QoS guarantees. home automation system required real-tine characteristics.