• Title/Summary/Keyword: Noise control

Search Result 4,657, Processing Time 0.029 seconds

A Study on Variable Speed Limit Strategies in Freeway Work Zone Using Multi-Criteria Decision Making Process (다기준 의사결정기반 고속도로 공사구간 VSL전략에 관한 연구)

  • Park, Juneyoung;Oh, Cheol;Chang, Myungsoon
    • Journal of Korean Society of Transportation
    • /
    • v.31 no.5
    • /
    • pp.3-15
    • /
    • 2013
  • The purpose of this study is to propose a methodology for operating variable speed limit (VSL) strategies in freeway work zones. A notable feature in this study is to incorporate a multi-criteria decision making process into deriving better VSL strategies. Decision criteria in this study include operational efficiency, safety, and environmental impacts. Travel speed, acceleration noise, and CO2 were used as performance measures for evaluating VSL strategies. A multi-criteria value function was developed through an analytical hierarchical process (AHP) for representing expert's knowledge. Then, a variety of VSL operations scenarios were investigated utilizing a microscopic traffic simulation suite, VISSIM. The proposed methodology would be useful in supporting more efficient, safer, and more environment-friendly traffic operations and control in freeway work zones.

A Study on the Enhancement of DEM Resolution by Radar Interferometry (레이더 간섭기법을 이용한 수치고도모델 해상도 향상에 관한 연구)

  • Kim Chang-Oh;Kim Sang-Wan;Lee Dong-Cheon;Lee Yong-Wook;Kim Jeong Woo
    • Korean Journal of Remote Sensing
    • /
    • v.21 no.4
    • /
    • pp.287-302
    • /
    • 2005
  • Digital Elevation Models (DEMs) were generated by ERS-l/2 and JERS-1 SAR interferometry in Daejon area, Korea. The quality of the DEM's was evaluated by the Ground Control Points (GCPs) in city area where GCPs were determined by GPS surveys, while in the mountain area with no GCPs, a 1:25,000 digital map was used. In order to minimize errors due to the inaccurate satellite orbit information and the phase unwrapping procedure, a Differential InSAR (DInSAR) was implemented in addition to the traditional InSAR analysis for DEM generation. In addition, DEMs from GTOPO30, SRTM-3, and 1:25,000 digital map were used for assessment the resolution of the DEM generated from DInSAR. 5-6 meters of elevation errors were found in the flat area regardless of the usage and the resolution of DEM, as a result of InSAR analyzing with a pair of ERS tandem and 6 pairs of JERS-1 interferograms. In the mountain area, however, DInSAR with DEMs from SRTM-3 and the digital map was found to be very effective to reduce errors due to phase unwrapping procedure. Also errors due to low signal-to-noise ratio of radar images and atmospheric effect were attenuated in the DEMs generated from the stacking of 6 pairs of JERS-1. SAR interferometry with multiple pairs of SAR interferogram with low resolution DEM can be effectively used to enhance the resolution of DEM in terms of data processing time and cost.

Development of a method for urban flooding detection using unstructured data and deep learing (비정형 데이터와 딥러닝을 활용한 내수침수 탐지기술 개발)

  • Lee, Haneul;Kim, Hung Soo;Kim, Soojun;Kim, Donghyun;Kim, Jongsung
    • Journal of Korea Water Resources Association
    • /
    • v.54 no.12
    • /
    • pp.1233-1242
    • /
    • 2021
  • In this study, a model was developed to determine whether flooding occurred using image data, which is unstructured data. CNN-based VGG16 and VGG19 were used to develop the flood classification model. In order to develop a model, images of flooded and non-flooded images were collected using web crawling method. Since the data collected using the web crawling method contains noise data, data irrelevant to this study was primarily deleted, and secondly, the image size was changed to 224×224 for model application. In addition, image augmentation was performed by changing the angle of the image for diversity of image. Finally, learning was performed using 2,500 images of flooding and 2,500 images of non-flooding. As a result of model evaluation, the average classification performance of the model was found to be 97%. In the future, if the model developed through the results of this study is mounted on the CCTV control center system, it is judged that the respons against flood damage can be done quickly.

Effects of Dose and Image Quality according to Center Location in Lumbar Spine Lateral Radiography Using AEC Mode (자동노출제어장치를 이용한 요추 측면 방사선검사 시 환자 중심 위치 변화가 선량과 화질에 미치는 영향)

  • Jeong, Woon-Chan;Joo, Young-Cheol
    • Journal of radiological science and technology
    • /
    • v.44 no.2
    • /
    • pp.85-90
    • /
    • 2021
  • The purpose of this study is to consider usefulness of using AEC mode and importance of patient center location in L-spine lateral radiography by comparing dose and image quality according to the change of patient center location with using AEC mode or not. In this study, guide wire is attached to the human body phantom's lumbar spine and the lead ruler is attached to the bottom of the wall detector to find out center location in detector. ESD, mAs, and EI were selected as dose factors, and image quality was compared through SNR. With the lumbar spine located center of the detector, dose factors and image quality were compared according to using AEC mode or not. Afterwards, phantom moved 4 cm and 8 cm back and forth and compared dose factors and image quality. The exposure parameters were 85 kVp, 320 mA, x-ray field size 10×17 inch, and the distance between the center X-ray and the detector was fixed at 100 cm. The center X-ray was perpendicular to the fourth lumbar spine and the only bottom AEC chamber was used. All data were analyzed by independent t-test and ANOVA. As a result of this study, with AEC when the center is matched, ESD was 1.31±0.01 mGy, without AEC was 2.12±0.01 mGy. SNR was shown to be 22.81±1.83, and 23.44±1.87 respectively. When the phantom's center moves 4 cm, 8 cm forward, and 4 cm, 8 cm backward, ESD were 1.09±0.004 mGy, 0.32±0.003 mGy, 1.19±0.017 mGy, 1.11±0.006 mGy respectively, SNR were 18.29±0.60 dB, 11.11±0.22 dB, 18.98±0.80 dB, 17.71±0.82 dB. Using AEC in L-spine lateral radiography reduced ESD by 38%, EI by 35%, and mAs by 38%, without any difference in SNR(p<0.05). When the phantom's center moves 4 cm, 8 cm forward, and 4 cm, 8 cm backward, ESD was decreasing each 16%, 75%, 9%, 15%, EI was decreasing each 14%, 77%, 15%, 20%, mAs was decreasing each 15% 75% 9%, 15%. SNR was decreasing each 19%, 51%, 17%, 22%.

Design of a Compact GPS/MEMS IMU Integrated Navigation Receiver Module for High Dynamic Environment (고기동 환경에 적용 가능한 소형 GPS/MEMS IMU 통합항법 수신모듈 설계)

  • Jeong, Koo-yong;Park, Dae-young;Kim, Seong-min;Lee, Jong-hyuk
    • Journal of Advanced Navigation Technology
    • /
    • v.25 no.1
    • /
    • pp.68-77
    • /
    • 2021
  • In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0×85.0×.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.

A Study on the Basic Direction of Housign Product Development Considering the Characteristics of Urban Townhouse (도시형 타운하우스의 특성을 고려한 주택상품개발의 기본 방향에 관한 연구)

  • Seong, Ki-Seon
    • Journal of Korea Entertainment Industry Association
    • /
    • v.14 no.4
    • /
    • pp.77-89
    • /
    • 2020
  • Nowadays, urban townhouses are being developed in various forms according to the characteristics of different regions in consideration of the trends of the housing market. Misperceiving the needs of consumers or their characteristics as a house for living, however, they often end up becoming products that are not suitable for urban life or degraded on account of reckless regional development. It is so unfortunate that such trial and error keeps being repeated. Urban townhouses are advantageous because there is no such problem as either invasion of privacy or noise from neighbors, and it is possible to have one's own garden and enlarged parking space, obtain quality of grounding, and plan unique interior and exterior design. They are also equipped with the strengths of apartment houses as well, for example, the efficiency of joint control in crime and disaster prevention or security, architecture of diaphragm walls with the separation of gates, or the planning of common space like a central square or park. Therefore, there is a great chance that they can be developed as the types of urban housing. Accordingly, the purpose of this study is to establish the basic direction of developing housing products right as space for urban life and maximize the roles of urban townhouses. By understanding their spatial as well as functional elements as a house for living, this author aims to provide a guideline for housing product development to realize urban townhouses that can meet consumer needs.

A Ship-Wake Joint Detection Using Sentinel-2 Imagery

  • Woojin, Jeon;Donghyun, Jin;Noh-hun, Seong;Daeseong, Jung;Suyoung, Sim;Jongho, Woo;Yugyeong, Byeon;Nayeon, Kim;Kyung-Soo, Han
    • Korean Journal of Remote Sensing
    • /
    • v.39 no.1
    • /
    • pp.77-86
    • /
    • 2023
  • Ship detection is widely used in areas such as maritime security, maritime traffic, fisheries management, illegal fishing, and border control, and ship detection is important for rapid response and damage minimization as ship accident rates increase due to recent increases in international maritime traffic. Currently, according to a number of global and national regulations, ships must be equipped with automatic identification system (AIS), which provide information such as the location and speed of the ship periodically at regular intervals. However, most small vessels (less than 300 tons) are not obligated to install the transponder and may not be transmitted intentionally or accidentally. There is even a case of misuse of the ship'slocation information. Therefore, in this study, ship detection was performed using high-resolution optical satellite images that can periodically remotely detect a wide range and detectsmallships. However, optical images can cause false-alarm due to noise on the surface of the sea, such as waves, or factors indicating ship-like brightness, such as clouds and wakes. So, it is important to remove these factors to improve the accuracy of ship detection. In this study, false alarm wasreduced, and the accuracy ofship detection wasimproved by removing wake.As a ship detection method, ship detection was performed using machine learning-based random forest (RF), and convolutional neural network (CNN) techniquesthat have been widely used in object detection fieldsrecently, and ship detection results by the model were compared and analyzed. In addition, in this study, the results of RF and CNN were combined to improve the phenomenon of ship disconnection and the phenomenon of small detection. The ship detection results of thisstudy are significant in that they improved the limitations of each model while maintaining accuracy. In addition, if satellite images with improved spatial resolution are utilized in the future, it is expected that ship and wake simultaneous detection with higher accuracy will be performed.

Design and Implementation of Biological Signal Measurement Algorithm for Remote Patient Monitoring based on IoT (IoT기반 원격환자모니터링을 위한 생체신호 측정 알고리즘 설계 및 구현)

  • Jung, Ae-Ran;You, Yong-Min;Lee, Sang-Joon
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
    • /
    • v.8 no.6
    • /
    • pp.957-966
    • /
    • 2018
  • Recently, the demand for remote patient monitoring based on IoT has been increased due to aging population and an increase in single-person household. A non-contact biological signal measurement system using multiple IR-UWB radars for remote patient monitoring is proposed in this paper. To reduce error signals, a multilayer Subtraction algorithm is applied because when the background subtraction algorithm was applied to the biological signal processing, errors occurred such as voltage noise and staircase phenomenon. Therefore, a multilayer background subtraction algorithm is applied to reduce error occurrence. The multilayer background subtraction algorithm extracts the signal by calculating the amount of change between the previous clutter and the current clutter. In this study, the SVD algorithm is used. We applied the improved multilayer background subtraction algorithm to biological signal measurement and computed the respiration rate through Fast Fourier Transform (FFT). To verify the proposed system using IR-UWB radars and multilayer background subtraction algorithm, the respiration rate was measured. The validity of this study was verified by obtaining a precision of 97.36% as a result of a control experiment with Neulog's attachment type breathing apparatus. The implemented algorithm improves the inconvenience of the existing contact wearable method.

Study on Analysis of Queen Bee Sound Patterns (여왕벌 사운드 패턴 분석에 대한 연구)

  • Kim Joon Ho;Han Wook
    • The Journal of the Convergence on Culture Technology
    • /
    • v.9 no.5
    • /
    • pp.867-874
    • /
    • 2023
  • Recently, many problems are occurring in the bee ecosystem due to rapid climate change. The decline in the bee population and changes in the flowering period are having a huge impact on the harvest of bee-keepers. Since it is impossible to continuously observe the beehives in the hive with the naked eye, most people rely on knowledge based on experience about the state of the hive.Therefore, interest is focused on smart beekeeping incorporating IoT technology. In particular, with regard to swarming, which is one of the most important parts of beekeeping, we know empirically that the swarming time can be determined by the sound of the queen bee, but there is no way to systematically analyze this with data.You may think that it can be done by simply recording the sound of the queen bee and analyzing it, but it does not solve various problems such as various noise issues around the hive and the inability to continuously record.In this study, we developed a system that records queen bee sounds in a real-time cloud system and analyzes sound patterns.After receiving real-time analog sound from the hive through multiple channels and converting it to digital, a sound pattern that was continuously output in the queen bee sound frequency band was discovered. By accessing the cloud system, you can monitor sounds around the hive, temperature/humidity inside the hive, weight, and internal movement data.The system developed in this study made it possible to analyze the sound patterns of the queen bee and learn about the situation inside the hive. Through this, it will be possible to predict the swarming period of bees or provide information to control the swarming period.

Robust Speech Recognition Algorithm of Voice Activated Powered Wheelchair for Severely Disabled Person (중증 장애우용 음성구동 휠체어를 위한 강인한 음성인식 알고리즘)

  • Suk, Soo-Young;Chung, Hyun-Yeol
    • The Journal of the Acoustical Society of Korea
    • /
    • v.26 no.6
    • /
    • pp.250-258
    • /
    • 2007
  • Current speech recognition technology s achieved high performance with the development of hardware devices, however it is insufficient for some applications where high reliability is required, such as voice control of powered wheelchairs for disabled persons. For the system which aims to operate powered wheelchairs safely by voice in real environment, we need to consider that non-voice commands such as user s coughing, breathing, and spark-like mechanical noise should be rejected and the wheelchair system need to recognize the speech commands affected by disability, which contains specific pronunciation speed and frequency. In this paper, we propose non-voice rejection method to perform voice/non-voice classification using both YIN based fundamental frequency(F0) extraction and reliability in preprocessing. We adopted a multi-template dictionary and acoustic modeling based speaker adaptation to cope with the pronunciation variation of inarticulately uttered speech. From the recognition tests conducted with the data collected in real environment, proposed YIN based fundamental extraction showed recall-precision rate of 95.1% better than that of 62% by cepstrum based method. Recognition test by a new system applied with multi-template dictionary and MAP adaptation also showed much higher accuracy of 99.5% than that of 78.6% by baseline system.