An Iterative Optimization Model for Hazardous Materials Transport with Demand Changes

Xianglong Sun,Shumin Feng,Zhenning Li 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1

Hazardous materials transportation network optimization can help to decrease accident rates and improve transport efficiency. An iterative optimization model of the transport network is established which considers characteristics of both government and enterprises. The first aim of government is to minimize transport risk, while enterprises want transport cost to be the lowest possible, so the top-level objective of this model is to minimize transport network risk and the low-level objective is to minimize total cost. When demand is determined, the total cost obtained from low-level model is added to top-level as constraints to determine the optimal transport network. When demand changes, we introduce safety coefficient to solve this model. A small transport network is used to verify this model and algorithm, and the results show that the proposed methods are feasible and stable.

An Algorithm for Traffic Flow Prediction Based on Improved SARIMA and GA

Xianglong Luo,Liyao Niu,Shengrui Zhang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

The traffic flow prediction plays a key role in modern Intelligent Transportation Systems (ITS). Although great achievements have been made in traffic flow prediction, it is still a challenge to improve the prediction accuracy and reduce the operation time simultaneously. In this paper, we proposed a hybrid prediction methodology combined with improved seasonal autoregressive integrated moving average (ISARIMA) model and multi-input autoregressive (AR) model by genetic algorithm (GA) optimization. Since traffic flow data has strong spatio-temporal correlation with neighboring stations, GA is used to select those stations which are highly correlated with the prediction station. The ISARIMA model is used to predict the traffic flow in test station at first. A multiinput AR model with traffic flow data in optimal selected stations is built to predict the traffic flow in test station as well. The final prediction result can be gained by combining with the results of ISARIMA and multi-input AR model. The test results from traffic data provided by TDRL at UMD Data Center demonstrate that proposed algorithm has almost the same prediction accuracy with artificial neural networks (ANNS). However, its operation time is almost the same with SARIMA model. It is proved to be an effective method to perform traffic flow prediction.

Simulation and Optimization of Crash Performance of Movable Barrier at Median Strip

Xianglong Sun,Zhihao Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.2

To better evaluate the crash performance of the guardrail and reduce the number of actual vehicle crash tests, this paper uses mechanical analysis and finite element simulation technology to evaluate the typical movable guardrail and optimize the structure. It’s of great significance for improving the crashworthiness of this type of guardrail and enhancing its safety performance. Firstly, the vehicle-barrier mechanical model was established to calculate the vehicle collision force on the barrier. Secondly, the collision force model was used to calculate the collision of a 10-ton truck, and a finite element model of a typical movable barrier was established for a collision simulation. Finally, the wall thickness and column spacing were optimized according to the results. The simulation results show that the maximum lateral dynamic deformation of the barrier was 1,818 mm, which agrees with the actual vehicle test results (1,600 mm). When the wall thickness of the barrier increases by 2 mm, the maximum lateral dynamic deformation was 1,419 mm; When the spacing of strengthened columns was reduced to 15 m, the deformation was 1,364 mm; After optimization, the deformation was reduced by more than 20%, and the crashworthiness of barrier was improved obviously.

Optimization of jumping motion of a legged robot for different take-off postures

Xianglong Wan,Takateru Urakubo,Yukio Tada 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

This paper deals with an optimal jumping motion of a four-link legged robot that minimizes the necessary joint torques during the motion. A fixed amount of translational energy is supplied to the robot from joint torques by the take-off time when the foot leaves theground, and the rotations of joints are stopped in the air by the time when the robot reaches the maximum height with the joints fullyextended. Numerical optimization results for different take-off postures show that the take-off posture that is close to a singular configurationhas an advantage in supplying translational energy efficiently in ground phase, and is also useful for reducing the rotational energythat has to be eliminated in aerial phase.

Estimation of Extreme Value Distribution and Return Levels for Annual Maximum of Daily Rainfall Amounts

Xianglong Liang,손건태 한국자료분석학회 2013 Journal of the Korean Data Analysis Society Vol.15 No.5

This study aims to estimate parameters and return levels of extreme value distributions and to examine dynamic features of return levels for annual maxima of daily rainfall amounts in South Korea. For this study, we used daily rainfall amounts in Seoul and Busan. Four kinds of extreme value distributions (GEVD, GPD, POT and Poisson-GPD) were applied to historical data and compared for each city separately. According to goodness-of-fit test and the estimation results of return levels, Gumbel-type GEVD was selected as the optimal distribution. Dynamic features of parameters and return levels of Gumbel-type GEVD were examined based on the moving-window method with shifting 30-year data period by one year separately. The estimates of parameters and return levels for Busan seem to be stable but those for Seoul are increasing.

Study on the Relationship Between Earthquake-induced Landslide Distribution and Topography in Wenchuan Earthquake

( Xianglong Yao ),( Shengwen Qi ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

The existing research proves that, unlike rainfall-induced landslides, earthquake landslides occur mostly in the high position of the slope, and the development of earthquake landslides has an obvious relationship with the topography. A large number of landslides induced in the Wenchuan earthquake also showed a similar relationship. The landslides occurred in the near fault area were large in density and large in scale, while the landslides in the areas far from the faults occurred mostly at the heights of the slopes and the landslide development density and scale were relatively reduced small. In this paper, five strip-shaped areas extending to the upper disc of the fault were selected in the upper seismic fault (central fault) of the Wenchuan earthquake, and the landslide boundary (without the accumulation area) was carefully interpreted. The object of research is to study the relationship between earthquake landslide and terrain. The study found that the scale of the earthquake landslide is mainly controlled by the fault distance and terrain.

Excitation of two-colored temporal solitons in a segmented quasi-phase-matching structure

Zeng, Xianglong,Ashihara, Satoshi,Wang, Zijie,Wang, Tingyun,Chen, Yuping,Cha, Myoungsik The Optical Society 2009 Optics express Vol.17 No.19

<P>We conducted a numerical study on the excitation of a two-colored temporal soliton in a segmented quasi-phase-matching (QPM) structure. The device has three parts: a periodic QPM grating for second-harmonic generation, a single domain for phase shift, and a periodic QPM grating for soliton evolution. The second harmonic pulse generated in the first grating works as a seed in the cascaded up-and-down conversions in the second grating. The numerical results showed that the second harmonic seeding enables the excitation of soliton pulses with an improved spatio-temporal intensity profile in a broad bandwidth of the wave-vector mismatch.</P>

일반화 극단치분포에 기초한 태풍 최량진로자료에 대한 재현수준 추정

손건태,Xianglong Liang 한국자료분석학회 2014 Journal of the Korean Data Analysis Society Vol.16 No.3

본 연구에서는 비상구역을 통과한 태풍의 연간빈도와 최대풍속에 대하여 일반화 극단치분포를 적합하고, 추정된 분포를 바탕으로 추정된 재현수준의 동적 특성을 조사하였다. 연구를 위하여 RSMC-Tokyo에서 제공하는 최량진로자료를 사용하였다. 해당 시계열에 대하여 자기상관성 검정을 수행하고, 일반화 극단치분포에 대한 적합도 검정을 수행하였다. 모수에 대한 최대가능도추정량을 산출한 후 재현수준을 추정하였다. 두 인자에 대하여 일반화 극단치분포가 잘 적합되었다. 분포의 동적변화를 알아보기 위하여 30년 이동창 방법을 사용하였으며, 변화에 따른 재현수준의 동적변화를 조사하였다. 태풍 빈도의 재현수준은 감소하고 있는 것으로 나타났다. 최대풍속 경우 30년 이동창에서는 검벨형 일반화 극단치분포가 적합한 것으로 나타났으며 30년 이동창 방법으로 추정된 재현수준은 초기에 증가하다가 안정적으로 변화된 것으로 나타났다. 재현수준의 동적변화가 있는 경우 최근 30년 자료를 사용하여 추정된 재현수준을 사용할 것을 제안한다. The objectives of present study are to apply an generalized extreme value distribution (GEVD) to two climatic factors, annual frequency and wind speed of typhoons which pass over the emergency area, and to examine the dynamic pattern of parameters in GEVD and return levels. For this study, the best track data offered by RSMC-Tokyo are used. According to autocorrelation test and goodness-of-fit test, GEVD fits well to two factors. Return levels are generated from the estimated GEVD. Dynamic characteristics of parameters in GEVD and return levels are examined based on 30-year moving-window method. Return levels for annual typhoon frequency are slowly decreasing and those for maximum wind speed seem to be stable.

Return Levels of Maximum Temperature in Busan, Korea

손건태,Xianglong Liang 한국자료분석학회 2013 Journal of the Korean Data Analysis Society Vol.15 No.1

The objectives of this study are to fit the extreme value distribution to maximum temperature and to examine dynamic patterns of distributions and return levels based on moving-windowing. As the extreme value distributions, we considered two extreme value distributions. The one is a generalized extreme value distribution (GEV) for the block maxima method and the other is a generalized Pareto distribution (GPD) for the threshold method. For this study, we used daily maximum temperatures in Busan, Korea, for a period of 51 years (1960 to 2010). Some return levels were obtained from the estimated distributions and compared. To examine the dynamic features, the GEV and the GPD were fitted to 30-year historical data and return levels were obtained from the estimated models. Dynamic features of parameters and return levels were examined based on the 30-year moving-window method with shifting data period separately.

A New Approach for Test Detection Using Homoge

Jianhua Huang,Xianglong Tang,Jiafeng Liu,Lili Xu 한국어정보학회 2006 한국어정보학 Vol.8 No.1

In this paper, a new approach for text detection in images and video based on homogeneity is studied. The texture analysis is applied to the homogeneity domain. Both local information and global information are used while calculating the homogeneity feature. Text region property is confirmed by using neural network trained to extract property feature by a fixed size text detector in homogeneity domain. Comparisons with text detection edge‐based method show that the proposed method has a better accuracy.