• Title/Summary/Keyword: 통신장애

Search Result 898, Processing Time 0.031 seconds

Development of a Mouse for Alternative Computer Access Using Smart Device (스마트기기를 이용한 컴퓨터 대체접근 마우스 개발)

  • Jang, U.H.;Hong, W.K.;Kim, C.G.;Song, B.S.
    • Journal of rehabilitation welfare engineering & assistive technology
    • /
    • v.8 no.1
    • /
    • pp.47-55
    • /
    • 2014
  • Almost of alternate computer access devices which assist people with disabilities to utilize the computer connected to computer by some cables or installed in as a S/W program. These devices have some spatial limitations to the people with disabilities, it can't guarantee the free and diverse access to the computer. For these reasons, in this paper, an Android-based mouse program for alternative computer access was developed. A people with physical disabilities who has some limitation of hand movements can use it in anywhere and anytime using only the fine motor skill of the upper limbs. The developed device recognizes the user's point touch and transforms it into the location of mouse cursor. The location information transferred to the computer via Bluetooth communication module equipped in smart devices. Also the group scanning method which can reduce the user's fatigue degree was employed and click, double click, drag & drop functions by hand's movements were equipped. The developed device will help the people with disabilities to use computer with brief touch and convenient operation without spatial limitation.

  • PDF

A Study on Measurement and Analysis of Pilot Channel Power at CDMA Communication Network (CDMA통신망에서 파일롯 채널전력 측정 및 분석에 관한 연구)

  • Jeong, Ki-Hyeok;Ra, Keuk-Hwan
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.44 no.6 s.360
    • /
    • pp.31-39
    • /
    • 2007
  • In this paper, a system for real-time or periodic measurement and analysis of RF parameters such as forward transmit power and pilot power in CDMA base station systems is proposed. Such RF characteristic parameter measurement can be prevented from system fault and used to achieve optimal service quality and maximum investment return through cell coverage expansion, subscriber capacity increase and so on. For forward power measurement, the local oscillator frequency for the detector is varied so that the transmit power for all channels can be measured. The channel power measurement can be used to analyze the variation in transmit power for changes in voice traffic. By comparing to forward $E_c/I_o$, the pilot channel power can be deducted, which can be used to determine uy degradation in transmit section modules such as the high dover amplifier. Since an accurate analysis of carefully measured data using the CDMA level detector must be made, the system is designed so that measurement errors due to changes in crest factor with modulation method can be overcome.

Real Time AOA Estimation Using Neural Network combined with Array Antennas (어레이 안테나와 결합된 신경망모델에 의한 실시간 도래방향 추정 알고리즘에 관한 연구)

  • 정중식;임정빈;안영섭
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2003.05a
    • /
    • pp.87-91
    • /
    • 2003
  • It has well known that MUSIC and ESPRIT algorithms estimate angle of arrival(AOA) with high resolution by eigenvalue decomposition of the covariance matrix which were obtained from the array antennas. However, the disadvantage of MUSIC and ESPRIT is that they are computationally ineffective, and then they are difficult to implement in real time. The other problem of MUSIC and ESRPIT is to require calibrated antennas with uniform features, and are sensitive to the manufacturing facult and other physical uncertainties. To overcome these disadvantages, several method using neural model have been study. For multiple signals, those require huge training data prior to AOA estimation. This paper proposes the algorithm for AOA estimation by interconnected hopfield neural model. Computer simulations show the validity of the proposed algorithm. The proposed method does not require huge training procedure and only assigns interconnected coefficients to the neural network prior to AOA estimation.

  • PDF

Symmetric Tree Replication Protocol for Efficient Distributed Storage System (효율적인 분산 저장 시스템을 위한 대칭 트리 복제 프로토콜)

  • 최성춘;윤희용;이강신;이호재
    • Journal of KIISE:Computer Systems and Theory
    • /
    • v.31 no.9
    • /
    • pp.503-513
    • /
    • 2004
  • In large distributed systems, replications of data and service are needed to decrease communication cost, increase availability, and avoid single server bottleneck. Tree Quorum protocol is a representative replication protocol, which exploits a logical structure. Tree quorum protocol is one of the replication protocols allowing low read cost only in the best case, while the number of replicas exponentially increases as the level grows. In this paper, thus, we propose a new replication protocol, called symmetric tree protocol which efficiently solves the problem. The proposed symmetric tree protocol also requires much smaller read cost than previous protocols. We conduct cost and availability analysis of the protocols, and the proposed protocol displays comparable read availability to the tree protocol using much smaller number of nodes. Also, the symmetric tree protocol has much smaller response time than the logarithmic protocol.

Isolation Control High Speed Transfer Switch for Upgrade Reliability of Uninterruptible Power Supply (USP의 신뢰성 향상을 위한 독립제어 고속절환장치)

  • Jung, Hyun-Chul;Hyun, Dong-Seok
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.13 no.4
    • /
    • pp.278-286
    • /
    • 2008
  • This paper investigates the fault generation type and the cause of output interruptionsin bulky with $30^{\sim}500[KVA]$ double conversion UPS, and proposes the fault detection method to improve the reliability of power supply used in the critical load in industry. Identifies its existing way of detecting a quality of inverter output it to bypass when exceeds its expectation. Under a UPS managing system, when an inner (Power device, Controller, CPU) fault occurs it disrupts the power supply and these occurrences has been verified by the results of experiments and application results. To overcome these problems, the proposed method constructs independently a fault-detection, a bypass-control device and a triple power supply apart from the conventional UPS operation. Also the detection point is changed to the preceding of a circuit breaker, a reference of fault detection is modified to avoid any clash and the breaking equipment is attached to intercept a spread of accident. As a result of applications of these developed systems to 242 UPS which was installed purposefully to the communication power supply, the service errors has not occurred in the UPS for two years since 2006.

Real Time AOA Estimation Using Analog Neural Network Model (아날로그 신경망 모델을 이용한 실시간 도래방향 추정 알고리즘의 개발)

  • Jeong, Jung-Sik
    • Journal of Navigation and Port Research
    • /
    • v.27 no.4
    • /
    • pp.465-469
    • /
    • 2003
  • It has well known that MUSIC and ESPRIT algorithms estimate angle of arrival(AOA) with high resolution by eigenvalue decomposition of the covariance matrix which were obtained from the array antennas, However, the disadvantage of MUSIC and ESPRIT is that they are computationally ineffective, and then they are difficult to implement in real time. the other problem of MUSIC and ESPRIT is to require calibrated antennas with uniform features, and are sensitive ti the manufacturing fault and other physical uncertainties. To overcome these disadvantages, several method using neural model have been study. For multiple signals, those methods require huge training data prior to AOA estimation. This paper proposes the algorithm for AOA estimation by interconnected Hopfield neural model. Computer simulations show the validity of the proposed algorithm. It follows that the proposed method yields better AOA estimates than MUSIC. Moreover, out method does not require huge training procedure and only assigns interconnected coefficients to the neural network prior to AOA estimation.

Image Based Human Action Recognition System to Support the Blind (시각장애인 보조를 위한 영상기반 휴먼 행동 인식 시스템)

  • Ko, ByoungChul;Hwang, Mincheol;Nam, Jae-Yeal
    • Journal of KIISE
    • /
    • v.42 no.1
    • /
    • pp.138-143
    • /
    • 2015
  • In this paper we develop a novel human action recognition system based on communication between an ear-mounted Bluetooth camera and an action recognition server to aid scene recognition for the blind. First, if the blind capture an image of a specific location using the ear-mounted camera, the captured image is transmitted to the recognition server using a smartphone that is synchronized with the camera. The recognition server sequentially performs human detection, object detection and action recognition by analyzing human poses. The recognized action information is retransmitted to the smartphone and the user can hear the action information through the text-to-speech (TTS). Experimental results using the proposed system showed a 60.7% action recognition performance on the test data captured in indoor and outdoor environments.

A Study on the Analysis of Ciliary Beat Frequency in Human Respiratory Tract n Vivo (레이저 산란 기법을 이용한 인체 기도 내 섬모 운동 신호의 분석에 관한 연구)

  • 이원진;이재서;이재서;이철희;권태영
    • Journal of Biomedical Engineering Research
    • /
    • v.21 no.4
    • /
    • pp.339-344
    • /
    • 2000
  • The mucociliary system is one of the most important airway defense mechanisms in human body and impairment of ciliary movement results in various diseases in respiratory tract. In this study, we have developed a system that can measure ciliary movement in vivo and quantified ciliary beat frequency (CBF) through autoregressive (AR) power spectrum. To measure the frequency in vivo, we applied a photoelectric method that was composed of a laser light and a fiber optic probe. Scattered signals are transferred to a PC in which they are displayed on the monitor and its CBF is determined by the AR method in were acquired. For 8 normal subjects, the analyzed CBFs ranged from 5 to 10Hz and its mean was 7.3${\pm}$1.1Hz. This result showed similar aspects to the reported results of CBFs to data. We expect that this result will be applied in various clinical studies such as analysis of CBF changes by drugs or by diseaes.

  • PDF

A Study on Encryption Module for Remote Terminal Security of Smart Water-Grid Network (스마트 워터그리드 네트워크의 원격 단말기 보안을 위한 암호화 모듈에 관한 연구)

  • Park, Seung-Hwan;Park, Hyung-Mo;Kim, Chang-Bok
    • Journal of Advanced Navigation Technology
    • /
    • v.17 no.6
    • /
    • pp.712-719
    • /
    • 2013
  • This paper studies the security module for the reliable transmission of the meter reading and the control data between the remote terminals and the upper server-side in smart water grid. The proposed security module was implemented to make it attachable to the remote terminal without security function. In particular, unlike the smart grid of electric field, the low power is considered due to the use of battery power in the smart water grid, and the ARIA-GCM-128 symmetric key method is adopted taking into the account that the damp and constrictive environments by the installed meter location in the underground occur a communication obstacle on building of the large-scale network system. The encryption module of this paper was devised to ensure the safety between the reading data on the terminal and the control data from the upper server, and secure the stability of the remote meter reading system by taking protection against an arbitrary alteration or modification.

An Integrative Method of FTA and FMEA for Software Security Analysis of a Smart Phone (스마트 폰의 소프트웨어 보안성 분석을 위한 FTA와 FMEA의 통합적 방법)

  • Kim, Myong-Hee;Toyib, Wildan;Park, Man-Gon
    • KIPS Transactions on Computer and Communication Systems
    • /
    • v.2 no.12
    • /
    • pp.541-552
    • /
    • 2013
  • Recently software security of the smart phone is an important issue in the field of information science and technology due to fast propagation of smart technology in our life. The smart phone as the security critical systems which are utilizing in terminal systems of the banking, ubiquitous home management, airline passengers screening, and so on are related to the risk of costs, risk of loss, risk of availability, and risk by usage. For the security issues, software hazard analysis of smart phone is the key approaching method by use of observed failures. In this paper, we propose an efficient integrative framework for software security analysis of the smart phone using Fault Tree Analysis (FTA) and Failure Mode Effect Analysis (FMEA) to gain a convergence security and reliability analysis technique on hand handle devices. And we discuss about that if a failure mode effect analysis performs simpler, not only for improving security but also reducing failure effects on this smart device, the proposed integrative framework is a key solution.