Calculation of Failure Probability of Caisson Breakwater Considering Correlation between Variables

Lu Wen Qie,최병호,Shi Leng Xie 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.1

In the general stochastic space, an asymptotic approximation of failure probability with random variables is presented in this paper. The extended Hasofer-Lind method for reliability index, together with asymptotic approximations of failure probability with correlated variables, is used in the reliability analysis for anti-sliding and anti-overturning of a caisson breakwater. The probability of failure modes of breakwater are carried out for an existing caisson breakwater at Qinhuangdao, China, and the accuracy of calculation result are also validated by comparing with the Level III method. It is shown that the probability of failure calculated by assuming independence of variables is less than that considering correlation among variables.

Two-Tier Interference Elimination for Femtocells Based on Cognitive Radio Centralized Spectrum Management

( Leng-gan Yi ),( Yi-min Lu ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.5

Femtocell provides better coverage and higher spectrum efficiency in areas rarely covered by macrocells. However, serious two-tier interference emerging from randomly deploying femtocells may create dead zones where the service is unavailable for macro-users. In this paper, we present adopting cognitive radio spectrum overlay to avoid intra-tier interference and incorporating spectrum underlay and overlay to coordinate cross-tier interference. It is a novel centralized control strategy appropriate for both uplink and downlink transmission. We introduce the application of proper spectrum sharing strategy plus optimal power allocation to address the issue of OFDM-based femtocells interference-limited downlink transmission, along with, a low-complexity suboptimal solution proposed. Simulation results illustrate the proposed optimal scheme achieves the highest transmission rate on successfully avoiding two- tier interference, and outperforms the traditional spectrum underlay or spectrum overlay, via maximizing the opportunity to transmit. Moreover, the strength of our proposed schemes is further demonstrated by comparison with previous classic power allocation methods, in terms of transmission rate, computational complexity and signal peak-to-average power ratio.

MODEL PREDICTIVE TRAJECTORY OPTIMIZATION AND TRACKING IN HIGHLY CONSTRAINED ENVIRONMENTS

Lu Xiong,Zhiqiang Fu,Zixuan Qian,Bo Leng,Dequan Zeng,Yanjun Huang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

This paper presents a model predictive trajectory optimization and tracking framework to avoid collisions for autonomous vehicles in highly constrained environments. Firstly, a vehicle model is established in road coordinate system to describe the relationship between the vehicle and the reference road. Secondly, a numerical optimization method is applied to smoothen the reference path generated by waypoints. Then, a multilayer searched method is used to establish a safe driving corridor in highly constrained environments. In addition, an optimal path optimization and tracking framework based on model predictive control is formulated to improve the driving safety and comfort. The proposed framework considers the constraints of path boundaries and vehicle dynamics to provide the optimal control command. Furthermore, the speed profile is optimized based on the longitudinal motion model in space domain to ensure the constraints of speed limits and vehicle acceleration. Finally, the proposed algorithms are evaluated through experiments in various scenarios to demonstrate the effectiveness.

CLIMATOLOGY, TREND ANALYSIS AND PREDICTION OF SANDSTORMS AND THEIR ASSOCIATED DUSTFALL IN CHINA

SUN, LENG,ZHOU, XUKAI,LU, JUNTIAN,KIM, YONG-PYO,CHUNG, YONG-SEUNG 한국교원대학교 환경과학연구소 2004 환경연구논문집 Vol.- No.8

Based on statistical data about Sand and Dust Storms (SDS) and their associated dustfall, features of temporal and spatial distribution were studied first in this aiticle. SDS and associated dustfalls occurred most often in northern China, especially northwestern China. However, in the last two years, they have a tendency to occur on the central and western parts of the Inner Mongolia Autonomous Region. As a result, Beijing is now among the impact areas, and the Chinese government is paying greater attention to the matter. The changing trends of SDS and associated dustfalls were subsequently analyzed. Occurrences were seen to be decreasing with the feature of fluctuation during the period of 1954-2001, but they have slightly increased since 2000. Also, climate factors related to SDS and associated dustfalls were discussed. Finally, it was recommended that methods to predict SDS in China be further studied in the future.

ALLOCATION CONTROL ALGORITHMS DESIGN AND COMPARISON BASED ON DISTRIBUTED DRIVE ELECTRIC VEHICLES

Bo Leng,Lu Xiong,Zhuoping Yu,Tong Zou 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.1

For a distributed drive electric vehicle (DDEV) which is equipped with redundant actuators, allocation control is a key technique. Three different allocation control algorithms are designated with fixed efficiency matrix, dynamic efficiency matrix, and direct yaw moment distribution, respectively. All these algorithms are applied in a vehicle stability control system with hierarchical control structure and evaluated from three aspects, namely, control precision, real-time characteristics, and control energy. Comparison results demonstrate that the algorithm with dynamic efficiency matrix has the best comprehensive performance, which is also validated in field tests based on a DDEV equipped with four motors.

Calculation of Failure Probability of Caisson Breakwater Considering Correlation between Variables

Qie, Lu Wen,Choi, Byung Ho,Xie, Shi Leng Korean Society of Civil Engineering 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.1

In the general stochastic space, an asymptotic approximation of failure probability with random variables is presented in this paper. The extended Hasofer-Lind method for reliability index, together with asymptotic approximations of failure probability with correlated variables, is used in the reliability analysis for anti-sliding and anti-overturning of a caisson breakwater. The probability of failure modes of breakwater are carried out for an existing caisson breakwater at Qinhuangdao, China, and the accuracy of calculation result are also validated by comparing with the Level III method. It is shown that the probability of failure calculated by assuming independence of variables is less than that considering correlation among variables.

Video Palmprint Recognition System Based on Modified Double-line-single-point Assisted Placement

Wu, Tengfei,Leng, Lu Korea Multimedia Society 2021 The journal of multimedia information system Vol.8 No.1

Palmprint has become a popular biometric modality; however, palmprint recognition has not been conducted in video media. Video palmprint recognition (VPR) has some advantages that are absent in image palmprint recognition. In VPR, the registration and recognition can be automatically implemented without users' manual manipulation. A good-quality image can be selected from the video frames or generated from the fusion of multiple video frames. VPR in contactless mode overcomes several problems caused by contact mode; however, contactless mode, especially mobile mode, encounters with several revere challenges. Double-line-single-point (DLSP) assisted placement technique can overcome the challenges as well as effectively reduce the localization error and computation complexity. This paper modifies DLSP technique to reduce the invalid area in the frames. In addition, the valid frames, in which users place their hands correctly, are selected according to finger gap judgement, and then some key frames, which have good quality, are selected from the valid frames as the gallery samples that are matched with the query samples for authentication decision. The VPR algorithm is conducted on the system designed and developed on mobile device.

Non-contact Palmprint Attendance System on PC Platform

Wu, Yuxin,Leng, Lu,Mao, Huapeng Korea Multimedia Society 2018 The journal of multimedia information system Vol.5 No.3

In order to overcome the problems of contact palmprint recognition, a non-contact palmprint recognition system is developed on personal computer (PC) platform. Three methods, namely "double-line-single-point" (DLSP), "double-assistant-crosshair" (DAC) and "none-assistant-graphic" (NAG), are implemented for the palmprint localization to solve the severe technical challenges, including the complex background, variant illuminations, uncontrollable locations and gestures of hands. In NAG, hand segmentation and the cropping of region of interest are performed without any assistant graphics. The convex hull contour of hand helps detect the outside contour of little finger as well as the valley bottom between thumb and index finger. The three methods of palmprint localization have good operating efficiency and can meet the performance requirements of real-time system. Furthermore, an attendance system on PC platform is designed and developed based on non-contact palmprint recognition.

Mobile Palmprint Segmentation Based on Improved Active Shape Model

Gao, Fumeng,Cao, Kuishun,Leng, Lu,Yuan, Yue Korea Multimedia Society 2018 The journal of multimedia information system Vol.5 No.4

Skin-color information is not sufficient for palmprint segmentation in complex scenes, including mobile environments. Traditional active shape model (ASM) combines gray information and shape information, but its performance is not good in complex scenes. An improved ASM method is developed for palmprint segmentation, in which Perux method normalizes the shape of the palm. Then the shape model of the palm is calculated with principal component analysis. Finally, the color likelihood degree is used to replace the gray information for target fitting. The improved ASM method reduces the complexity, while improves the accuracy and robustness.

Color Analysis for the Quantitative Aesthetics of Qiong Kiln Ceramics

Wang, Fei,Cha, Hang,Leng, Lu Korea Multimedia Society 2020 The journal of multimedia information system Vol.7 No.2

The subjective experience would degrade the current artificial artistic aesthetic analysis. Since Qiong kiln ceramics have a long history and occupy a very important position in ceramic arts, we employed computer-aided technologies to quickly automatically accurately and quantitatively process a large number of Qiong kiln ceramic images and generate the detailed statistical data. Because the color features are simple and significant visual characteristics, the color features of Qiong kiln ceramics are analyzed for the quantitative aesthetics. The Qiong kiln ceramic images are segmented with GrabCut algorithm. Three moments (1st-order, 2nd-order, and 3rd-order) are calculated in two typical color spaces, namely RGB and HSV. The discrimination powers of the color features are analyzed according to various dynasties (Tang Dynasty, Five Dynasties, Song Dynasty) and various utensils (Pot, kettle, bowl), which are helpful to the selection of the discriminant color features among various dynasties and utensils. This paper is helpful to promoting the quantitative aesthetic research of Qiong kiln ceramics and is also conducive to the research on the aesthetics of other ceramics.