• Title/Summary/Keyword: 적응적 테스트

Search Result 125, Processing Time 0.041 seconds

Adaptive Enhancement of Low-light Video Images Algorithm Based on Visual Perception (시각 감지 기반의 저조도 영상 이미지 적응 보상 증진 알고리즘)

  • Li Yuan;Byung-Won Min
    • Journal of Internet of Things and Convergence
    • /
    • v.10 no.2
    • /
    • pp.51-60
    • /
    • 2024
  • Aiming at the problem of low contrast and difficult to recognize video images in low-light environment, we propose an adaptive contrast compensation enhancement algorithm based on human visual perception. First of all, the video image characteristic factors in low-light environment are extracted: AL (average luminance), ABWF (average bandwidth factor), and the mathematical model of human visual CRC(contrast resolution compensation) is established according to the difference of the original image's grayscale/chromaticity level, and the proportion of the three primary colors of the true color is compensated by the integral, respectively. Then, when the degree of compensation is lower than the bright vision precisely distinguishable difference, the compensation threshold is set to linearly compensate the bright vision to the full bandwidth. Finally, the automatic optimization model of the compensation ratio coefficient is established by combining the subjective image quality evaluation and the image characteristic factor. The experimental test results show that the video image adaptive enhancement algorithm has good enhancement effect, good real-time performance, can effectively mine the dark vision information, and can be widely used in different scenes.

Step Count Detection Algorithm and Activity Monitoring System Using a Accelerometer (가속도 센서를 이용한 보행 횟수 검출 알고리즘과 활동량 모니터링 시스템)

  • Kim, Yun-Kyung;Lho, Hyung-Suk;Cho, We-Duke
    • Journal of the Institute of Electronics Engineers of Korea CI
    • /
    • v.48 no.2
    • /
    • pp.127-137
    • /
    • 2011
  • We have developed a wearable device that can convert sensor data into real-time step counts and activity levels. Sensor data on gait were acquired using a triaxial accelerometer. A test was performed according to a test protocol for different walking speeds, e.g., slow walking, walking, fast walking, slow running, running, and fast running. Each test was carried out for 36 min on a treadmill with the participant wearing a portable gas analyzer (K4B2), an Actical device, and the device developed in this study. The signal vector magnitude (SVM) was used to process the X, Y, and Z values output by the triaxial accelerometer into one representative value. In addition, for accurate step-count detection, we used three algorithms: an heuristic algorithm (HA), the adaptive threshold algorithm (ATA), and the adaptive locking period algorithm (ALPA). A regression equation estimating the energy expenditure (EE) was derived by using data from the accelerometer and information on the participants. The recognition rate of our algorithm was 97.34%, and the performance of the activity conversion algorithm was better than that of the Actical device by 1.61%.

Performance Prediction for an Adaptive Optics System Using Two Analysis Methods: Statistical Analysis and Computational Simulation (통계분석 및 전산모사 기법을 이용한 적응광학 시스템 성능 예측)

  • Han, Seok Gi;Joo, Ji Yong;Lee, Jun Ho;Park, Sang Yeong;Kim, Young Soo;Jung, Yong Suk;Jung, Do Hwan;Huh, Joon;Lee, Kihun
    • Korean Journal of Optics and Photonics
    • /
    • v.33 no.4
    • /
    • pp.167-176
    • /
    • 2022
  • Adaptive optics (AO) systems compensate for atmospheric disturbance, especially phase distortion, by introducing counter-wavefront deformation calculated from real-time wavefront sensing or prediction. Because AO system implementations are time-consuming and costly, it is highly desirable to estimate the system's performance during the development of the AO system or its parts. Among several techniques, we mostly apply statistical analysis, computational simulation, and optical-bench tests. Statistical analysis estimates performance based on the sum of performance variances due to all design parameters, but ignores any correlation between them. Computational simulation models every part of an adaptive optics system, including atmospheric disturbance and a closed loop between wavefront sensor and deformable mirror, as close as possible to reality, but there are still some differences between simulation models and reality. The optical-bench test implements an almost identical AO system on an optical bench, to confirm the predictions of the previous methods. We are currently developing an AO system for a 1.6-m ground telescope using a deformable mirror that was recently developed in South Korea. This paper reports the results of the statistical analysis and computer simulation for the system's design and confirmation. For the analysis, we apply the Strehl ratio as the performance criterion, and the median seeing conditions at the Bohyun observatory in Korea. The statistical analysis predicts a Strehl ratio of 0.31. The simulation method similarly reports a slightly larger value of 0.32. During the study, the simulation method exhibits run-to-run variation due to the random nature of atmospheric disturbance, which converges when the simulation time is longer than 0.9 seconds, i.e., approximately 240 times the critical time constant of the applied atmospheric disturbance.

Adaptive Packet Scheduling Scheme for Enhancing the PSM Performance of Mobile Devices (모바일 단말의 PSM 성능 향상을 위한 적응적 패킷 스케줄링 기법)

  • Park, Young Deok;Jung, Kyoung-Hak;Suh, Young-Joo
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.38B no.8
    • /
    • pp.623-631
    • /
    • 2013
  • Wireless LAN (WLAN) interface is one of the major sources drastically depleting the battery power of mobile devices such as smartphones and tablets. Most commercial mobile devices employ a power saving technique putting their WLAN interface into a sleep state when there is no network traffic, and thereby, save the battery power. However, since an access point (AP) just transmits the packet(s) received from a server to the corresponding mobile device immediately, it may cause a problem that the mobile device constantly remains in an awake state so that its battery power is rapidly drained. In this paper, we point out this problem and propose a new scheme that can save the mobile device's battery power with an adaptive packet scheduling at the AP side. From the experimental results based on a testbed, we found that the proposed scheme outperforms existing schemes over 50% in terms of power saving.

An 8-Gb/s/channel Asymmetric 4-PAM Transceiver with an Adaptive Pre-emphasis for Memory Interface (메모리 인터페이스를 위한 적응형 프리엠퍼시스를 가지는 8-Gb/s/채널 비균형 4-레벨 펄스진폭변조 입출력회로)

  • Jang, Young-Chan;Jun, Young-Hyun
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.46 no.8
    • /
    • pp.71-78
    • /
    • 2009
  • An 8${\times}$8-Gb/s/channel 4-PAM transceiver was designed for high speed memory applications by using 70nm DRAM process with 1.35V supply. An asymmetric 4-PAM signaling scheme is proposed to increase the voltage and time margin of upper and lower eyes in 3-class eye opening. A mathematical basis shows that this scheme statistically reduces 33% of reference noise effect in a receiver. Also, an adaptive pre-emphasis scheme, which utilizes a lone-bit pulse with integrator at the receiver, is introduced to reduce ISI for a simple DRAM channel. In this scheme, an integrating clock timing calibration by using a pre-determined pattern is proposed for the optimum ISI measurement.

An FPGA Implementation of Acoustic Echo Canceller Using S-LMS Algorithm (S-LMS 알고리즘을 이용한 음향반향제거기의 FPGA구현)

  • 이행우
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.9
    • /
    • pp.65-71
    • /
    • 2004
  • This paper describes a new adaptive algorithm which can reduce the required computation quantities in the adaptive filter. The proposed S-LMS algorithm uses only the signs of the normalized input signal rather than the input signals when coefficients of the filter are adapted. By doing so, there is no need for the multiplications and divisions which are mostly responsible for the computation quantities. To analyze the convergence characteristics of the proposed algorithm, the condition and speed of the convergence are derived mathematically. Also, we simulate an echo canceller adopting this algorithm and compare the performances of convergence for this algorithm with the ones for the other algorithm. As the results of simulations, it is proved that the echo canceller adopting this algorithm shows almost the same performances of convergence as the echo canceller adopting the SIA algorithm.

Digital Watermarking using the suitable watermark strength and length (최적의 워터마크 강도와 길이를 이용한 디지털 워터마킹)

  • Lee, Young-Hee;Lee, Jung-Hee;Cha, Eui-Young
    • The Journal of Korean Association of Computer Education
    • /
    • v.9 no.5
    • /
    • pp.77-84
    • /
    • 2006
  • In this paper, we propose an adaptive image watermarking algorithm in DWT domain by using HVS(human Visual system) and SOM(Self-Organizing Map) among neural networks. HVS can be described in terms of two properties of HVS: brightness and texture sensitivity. The SOM is used to obtain the local characteristics of image, Therefore, the suitable strength and length of embedded watermark is determined by using HVS and SOM. The experimental results show that proposed method provides a suitable strength and length of watermark and has good perceptual invisibility and robustness for various attacks.

  • PDF

Printed Hangul Recognition with Adaptive Hierarchical Structures Depending on 6-Types (6-유형 별로 적응적 계층 구조를 갖는 인쇄 한글 인식)

  • Ham, Dae-Sung;Lee, Duk-Ryong;Choi, Kyung-Ung;Oh, Il-Seok
    • The Journal of the Korea Contents Association
    • /
    • v.10 no.1
    • /
    • pp.10-18
    • /
    • 2010
  • Due to a large number of classes in Hangul character recognition, it is usual to use the six-type preclassification stage. After the preclassification, the first consonent, vowel, and last consonent can be classified separately. Though each of three components has a few of classes, classification errors occurs often due to shape similarity such as 'ㅔ' and 'ㅖ'. So this paper proposes a hierarchical recognition method which adopts multi-stage tree structures for each of 6-types. In addition, to reduce the interference among three components, the method uses the recognition results of first consonents and vowel as features of vowel classifier. The recognition accuracy for the test set of PHD08 database was 98.96%.

The Effects of Elements of Learning Information's Record on the Correctness of Decision When Applied to the E-Learning based on CAT with SPRT Model (e-러닝 기반의 SPRT형 CAT모델에서 학습정보이력 요소의 적용이 판정의 정확성에 미치는 영향)

  • Kim, Kyung-Hyun
    • The Journal of Korean Association of Computer Education
    • /
    • v.10 no.5
    • /
    • pp.71-79
    • /
    • 2007
  • The purpose of this research is to show that elements of learning information's record(learning time and the score of practice test) have a significant effect on the correctness of decision when they are applied to e-Learning based on CAT with SPRT model. Especially, the score of practice test can be used in the real e-learning environment as its effect showed approximately 90% improvement. Therefore, if we apply learning information's record to SPRT in evaluation, we can evaluate the learner's ability more precisely and quickly, contributing to the enhancement of the individualization of learners. If an algorithm with variables from learning information's record can be developed, a better e-Learning evaluation program will be made in the future.

  • PDF

An Input Transformation with MFCCs and CNN Learning Based Robust Bearing Fault Diagnosis Method for Various Working Conditions (MFCCs를 이용한 입력 변환과 CNN 학습에 기반한 운영 환경 변화에 강건한 베어링 결함 진단 방법)

  • Seo, Yangjin
    • KIPS Transactions on Software and Data Engineering
    • /
    • v.11 no.4
    • /
    • pp.179-188
    • /
    • 2022
  • There have been many successful researches on a bearing fault diagnosis based on Deep Learning, but there is still a critical issue of the data distribution difference between training data and test data from their different working conditions causing performance degradation in applying those methods to the machines in the field. As a solution, a data adaptation method has been proposed and showed a good result, but each and every approach is strictly limited to a specific applying scenario or presupposition, which makes it still difficult to be used as a real-world application. Therefore, in this study, we have proposed a method that, using a data transformation with MFCCs and a simple CNN architecture, can perform a robust diagnosis on a target domain data without an additional learning or tuning on the model generated from a source domain data and conducted an experiment and analysis on the proposed method with the CWRU bearing dataset, which is one of the representative datasests for bearing fault diagnosis. The experimental results showed that our method achieved an equal performance to those of transfer learning based methods and a better performance by at least 15% compared to that of an input transformation based baseline method.