• Title/Summary/Keyword: speed data

Search Result 8,853, Processing Time 0.038 seconds

A Development of the Operating Speed Estimation Model of Truck on Four-lane Rural Highway (지방부 일반국도 4차로의 화물차 주행속도 예측모형 개발)

  • Park, Min Ho;Lee, Geun Hee
    • International Journal of Highway Engineering
    • /
    • v.16 no.5
    • /
    • pp.173-182
    • /
    • 2014
  • PURPOSES : The purpose of the study is to a) explore the operating speed of trucks on rural highways affected by road geometry, and thereby b) develop a predictive model for the operating speed of trucks on rural highways. METHODS : Considering that most of the existing studies have focused on cars, the current study aimed to predict the operating speed of trucks by conducting linear regression analysis on the speed data of trucks operating on the linear-curved-linear portions of the road as a single set. RESULTS : The operating speed in the plane curve portion increased with the length of the curve, and decreased with a lower vertical grade and a smaller curve radius. In the straight plane portion, the operating speed increased with a larger curve radius(upstream), and decreased with an increase in the change of the vertical grade, depending on the length of the vertical curve. CONCLUSIONS : This study developed estimation models of truck for operational speed and evaluated the degree of safety for horizontal and vertical alignments simultaneous. In order to represent whole area of the rural highway, the models should be ew-analyzed with vast data related with road alignment factor in the near future.

Low-Cost CRC Scheme by Using DBI(Data Bus Inversion) for High Speed Semiconductor Memory (고속반도체 메모리를 위한 DBI(Data Bus Inversion)를 이용한 저비용 CRC(Cyclic Redundancy Check)방식)

  • Lee, Joong-Ho
    • Journal of IKEEE
    • /
    • v.19 no.3
    • /
    • pp.288-294
    • /
    • 2015
  • CRC function has been built into the high-speed semiconductor memory device in order to increase the reliability of data for high-speed operation. Also, DBI function is adopted to improve of data transmission speed. Conventional CRC(ATM-8 HEC code) method has a significant amounts of area-overhead(~XOR 700 gates), and processing time(6 stage XOR) is large. Therefore it leads to a considerable burden on the timing margin at the time of reading and writing of the low power memory devices for CRC calculations. In this paper, we propose a CRC method for low cost and high speed memory, which was improved 92% for area-overhead. For low-cost implementation of the CRC scheme by the DBI function it was supplemented by data bit error detection rate. And analyzing the error detection rate were compared with conventional CRC method.

Rotor Coastdown and Acceleration Performances of High-speed Motors Supported on Ball Bearings and Gas Foil Bearings (볼 베어링 및 가스 포일 베어링으로 지지되는 고속 전동기의 회전체 관성정지 및 가속 성능 연구)

  • Mun, HyeongWook;Seo, JungHwa;Kim, TaeHo
    • Tribology and Lubricants
    • /
    • v.35 no.2
    • /
    • pp.123-131
    • /
    • 2019
  • This study characterizes the coastdown performances of two small electric motors supported on high-speed ball bearings (BBs) and gas foil bearings (GFBs), and it predicts their acceleration performances. The two motors have identical permanent magnetic rotors and mating stators. However, the shaft of the GFBs has a larger mass and polar/transverse moments of inertia than that of the BBs. Motor coastdown tests demonstrate that the rotor speed decreases linearly with the BBs and nonlinearly with the GFBs. A simple model for the BBs predicts a constant drag torque and linear decay of speed with time. The test data validate the model predictions. For the GFBs, the hydrodynamic lubrication model predictions reveal that the drag torque increases linearly with speed, and the speed decreases exponentially with time. The predictions agree very well with the test data in the speed range of 100-30 krpm. The boundary lubrication model predicts a constant drag torque and linear decay of speed with time. The predictions agree well with the test data below 15 krpm. Mixed lubrication occurs in the speed range of 30-15 krpm. Rotor acceleration performances are predicted based on the characteristics of deceleration performances. The GFBs require more time to reach 100,000 krpm than the BBs because of their larger shaft polar moment of inertia. However, predictions for the assumed identical polar moment of inertia reveal that the GFBs have a nearly identical acceleration performance to that of the BBs with a motor torque greater than $0.03N{\cdot}m$.

The Improvement of Adaptive Transversal Filter with Data-Recycling LMS Algorithms Convergence Speed (데이터-재순환 최소 평균 자승 알고리즘을 이용한 적응 횡단선 필터의 수렴속도 개선)

  • Oh, Seung-Jae
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.4 no.3
    • /
    • pp.224-229
    • /
    • 2009
  • In this paper, an efficient signal interference control technique to improve the convergence speed of Adaptive transversal filter with LMS algorithm is introduced. The convergence characteristics of the proposed algorithm, whose coefficients are multiply adapted in a symbol time period by recycling the received data, are analyzed to prove theoretically the improvement of convergence speed. According as the step-size parameter ${\mu}$ is increased, the rate of convergence of the algorithm is controlled. Increasing the eigenvalue spread has the effect of controlling down the rate of convergence of the adaptive equalizer and also increasing the steady-state value of the average squared error and also demonstrate the superiority of signal interference control to the filter algorithm increasing convergence speed by (B+1) times due to the data-recycling LMS Algorithms.

  • PDF

A Study on Constant-Speed Position Control of Solid Freeform Fabrication System (임의형상가공시스템의 정속위치제어)

  • Jung, Yong-Rae;Ko, Min-Kook;Kim, Seung-Woo
    • Proceedings of the KIEE Conference
    • /
    • 2002.11c
    • /
    • pp.75-78
    • /
    • 2002
  • SFFS(Solid Freeform Fabrication System) is commercializing to rapid prototyping concept in world-wide some corporations including the States, have much technological problems yet and need new mode for agile solid freeform fabrication as well as prototyping. In this paper, we design an automatic control algorithm that the cutting path of laser beam, on the SFFS, is controlled with constant speed. The designed algorithm for constant-speed path control is implemented and experimented in the $CAFL^{VM}$ (Computer Aided Fabrication of Lamination for Various Material) system, the new SFFS which is developed in this paper. Its process is an automated fabrication method in which a 3D object is constructed from STL(SToreoLithography) 2D data, derived from CAD 3D image, by sequentially laminating the part cross-sections. The constant-speed path control is started from the STL data. After STL file is modified in data format to be available for control. The fabrication of the 2D part is, with constant speed, conducted from the 23 position data by laser beam. we confirm its high-performance through experiment results from the application into $CAFL^{VM}$ system.

  • PDF

A Study on Network Operation Structure and DataLink Protocol for Interworking of Ground Network ALL-IP at Next-Military Satellite Communication (차기군위성통신에서 지상망 ALL-IP 연동을 위한 네트워크 운용구조 및 데이터링크 프로토콜 연구)

  • Lee, Changyoung;Kang, Kyungran;Shim, Yong-hui
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.21 no.6
    • /
    • pp.826-841
    • /
    • 2018
  • The military satellite communication of ROK military, ANASIS is designed for analog data such as voice and streaming data. ANASIS cannot fully support ALL-IP communications due to its long propagation delay. The next generation satellite communication system is being designed to overcome the limitation. Next generation satellite communications system considers both high-speed and low-speed networks to support various operating environment. The low-speed satellite supports both broadband and narrow-band communication. This network works as the infrastructure for of wide-area internetworking over multiple AS's in the terrestrial network. It requires minimum satellite frequency and minimum power and works without PEP and router. In this paper, we propose a network operation structure to enable the inter-operation between high and low-speed satellite networks. In addition, we propose a data link protocol for low speed satellite networks.

Extreme wind climatology of Nepal and Northern India

  • Manoj Adhikari;Christopher W. Letchford
    • Wind and Structures
    • /
    • v.37 no.2
    • /
    • pp.153-161
    • /
    • 2023
  • Wind speed data from Nepal and adjoining countries have been analyzed to estimate an extreme wind speed climatology for the region. Previously wind speed information for Nepal was adopted from the Indian National Standard and applied to two orographically different regions: above and below 3000 m elevation respectively. Comparisons of the results of this analysis are made with relevant codes and standards. The study confirms that the assigned basic wind speed of 47 m/s for the plains and hills of Nepal (below 3000 m) is appropriate, however, data to substantiate a basic wind speed of 55 m/s above 3000 m is unavailable. Using a composite analysis of 15 geographically similar stations, the study also generated 435 years of annual maxima wind data and fitted them to Type I and Type III extreme value distributions. The results suggest that Type III distribution may better represent the data. The findings are also consistent with predictions made by Holmes and Weller (2002) and to a certain extent those of Sarkar et al. (2014), but lower than the analysis undertaken by Lakshmanan et al. (2009) for northern India. The study also highlights that the use of a load factor of 1.5 on wind load implies lower strength design MRI's of around 260 years compared to the 700 years of ASCE 7-22.

A Study on the Characteristics of Transferring Vibration and Effect of Nearby-Building Induced by the High-speed Train in Operation (고속철도 운행에 의한 진동전달특성 및 인접건물에 미치는 영향에 관한 연구)

  • 배동명;신창혁;최철은;박상곤;백용진
    • Journal of KSNVE
    • /
    • v.11 no.2
    • /
    • pp.354-364
    • /
    • 2001
  • The vibration induced by high speed train running on rail is dealt with as an environmental problem. The train induced vibration is characterized by moving loads at specific frequencies and soil conditions. In fact, it is predicted that the vibration sources are involved the wheel distance, number of cars, speed of operation, drift of rails, structural born vibration, etc. In this paper the characteristics of transferring vibration induced by the high-speed train in operation is discussed. Field measurements was conducted at region from Chungnam Yungj So-jung-myan to Chungbuk Chungwon hyun-do-myun. In the near future. these data will be used as the fundamental data for establishment of the countermeasure for vibrational reduction of high speed train using the results of the field measurements and quantitative prediction of the vibration level

  • PDF

A Study on the Resistance Property of Hard Chine Type High Speed Planing Craft (HARD CHINE형 활주 고속선의 저항특성에 관한 고찰)

  • 이창억
    • Journal of the Korean Professional Engineers Association
    • /
    • v.16 no.2
    • /
    • pp.1-11
    • /
    • 1983
  • The resistance property of a high speed passenger craft (: "DOL-PIN HO" designed by the author in 1972) is investigated as follows; -. The Resistance property of the craft is determined by savitsky′s method and blount-Fox′s method. The theoretical results are also compared with the full scale data. The comparison reveals that the result when using blount/fox′s method are in much closer agreement with the full scale data than savitsky′s. -. The effects of ship speed on the positions of the center of pressure and of the longitudinal center of gravity (L.C.G.) are investigated. The investigation shows that the position of L.C.G. of the craft is almost constant although the ship speed is changed. -. The effect of transom flap on the Resistance property of the craft is studied using savitsky/brown′s method. From the study it is found that the resistance of the craft is decreased and hence speed gain (about 3% of the service speed) can be obtained, when using transom flap for the craft.

  • PDF

En-route Ground Speed Prediction and Posterior Inference Using Generative Model (생성 모형을 사용한 순항 항공기 향후 속도 예측 및 추론)

  • Paek, Hyunjin;Lee, Keumjin
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.27 no.4
    • /
    • pp.27-36
    • /
    • 2019
  • An accurate trajectory prediction is a key to the safe and efficient operations of aircraft. One way to improve trajectory prediction accuracy is to develop a model for aircraft ground speed prediction. This paper proposes a generative model for posterior aircraft ground speed prediction. The proposed method fits the Gaussian Mixture Model(GMM) to historical data of aircraft speed, and then the model is used to generates probabilistic speed profile of the aircraft. The performances of the proposed method are demonstrated with real traffic data in Incheon Flight Information Region(FIR).