scholarly journals Vessel Scheduling Optimization Model Based on Variable Speed in a Seaport with One-Way Navigation Channel

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5478
Author(s):  
Dongdong Liu ◽  
Guoyou Shi ◽  
Katsutoshi Hirayama
Keyword(s):  
Traffic Safety ◽  
Linear Problem ◽  
Time Window ◽  
Time Interval ◽  
Variable Speed ◽  
Vessel Scheduling ◽  
Navigation Channel ◽  
Scheduling Method ◽  
Constraint Problem ◽  
First In First Out

To improve the efficiency of in-wharf vessels and out-wharf vessels in seaports, taking into account the characteristics of vessel speeds that are not fixed, a vessel scheduling method with whole voyage constraints is proposed. Based on multi-time constraints, the concept of a minimum safety time interval (MSTI) is clarified to make the mathematical formula more compact and easier to understand. Combining the time window concept, a calculation method for the navigable time window constrained by tidal height and drafts for vessels is proposed. In addition, the nonlinear global constraint problem is converted into a linear problem discretely. With the minimum average waiting time as the goal, the genetic algorithm (GA) is designed to optimize the reformulated vessel scheduling problem (VSP). The scheduling methods under different priorities, such as the first-in-first-out principle, the largest-draft-vessel-first-service principle, and the random service principle are compared and analyzed experimentally with the simulation data. The results indicate that the reformulated and simplified VSP model has a smaller relative error compared with the general priority scheduling rules and is versatile, can effectively improve the efficiency of vessel optimization scheduling, and can ensure traffic safety.

scholarly journals Fuzzy Scheduling Problem of Vessels in One-Way Waterway

2021 ◽  
Vol 9 (10) ◽  
pp. 1064
Author(s):  
Dongdong Liu ◽  
Guoyou Shi ◽  
Zhen Kang
Keyword(s):  
Traffic Safety ◽  
Time Window ◽  
Fuzzy Theory ◽  
Scheduling Algorithm ◽  
Simulated Data ◽  
Optimization Method ◽  
Triangular Fuzzy Number ◽  
Scheduling Problems ◽  
Vessel Scheduling ◽  
Fuzzy Scheduling

Effective use of port waterways is conducive to enhancing port competitiveness. To minimize the waiting time of ships, improve traffic efficiency, and enhance the applicability of the model to the presence of uncertain factors, a fuzzy scheduling optimization method for ships suitable for one-way waterways is proposed based on fuzzy theory. Considering the ambiguity of the speed of ships entering and exiting the port or the time it takes to cross the channel, the previous research on vessel scheduling on one-way waterways has been extended by introducing a triangular fuzzy number and a method for determining the feasible navigable time window of a ship subject to the tide height constraint was proposed. In this study, the genetic algorithm is used to construct the mathematical model for solving fuzzy vessel scheduling problems based on time optimization, and the minimum delay strategy is used to determine the service sequence. Then, the parameters setting are discussed in detail to find the optimal settings. Finally, an experimental comparative analysis of the randomly generated cases was conducted based on the simulated data. The results show that the designed fuzzy vessel scheduling algorithm reduces the dependence on the port environment, is versatile, and can effectively improve the efficiency of ship schedules and traffic safety compared to other methods. Moreover, it can avoid the problem of the illegal solution occurring in the manual scheduling method.

Parameters of Spike Trains Observed in a Short Time Window

2008 ◽  
Vol 20 (5) ◽  
pp. 1325-1343 ◽  
Author(s):  
Zbyněk Pawlas ◽  
Lev B. Klebanov ◽  
Martin Prokop ◽  
Petr Lansky
Keyword(s):  
Coefficient Of Variation ◽  
Point Processes ◽  
Interspike Interval ◽  
Time Window ◽  
Time Windows ◽  
Time Interval ◽  
Short Time Interval ◽  
Target Neuron ◽  
Short Time Window ◽  
Short Time

We study the estimation of statistical moments of interspike intervals based on observation of spike counts in many independent short time windows. This scenario corresponds to the situation in which a target neuron occurs. It receives information from many neurons and has to respond within a short time interval. The precision of the estimation procedures is examined. As the model for neuronal activity, two examples of stationary point processes are considered: renewal process and doubly stochastic Poisson process. Both moment and maximum likelihood estimators are investigated. Not only the mean but also the coefficient of variation is estimated. In accordance with our expectations, numerical studies confirm that the estimation of mean interspike interval is more reliable than the estimation of coefficient of variation. The error of estimation increases with increasing mean interspike interval, which is equivalent to decreasing the size of window (less events are observed in a window) and with decreasing the number of neurons (lower number of windows).

Dual Resource Constrained Job Shop Dynamic Scheduling with Local Time Window

2014 ◽  
Vol 933 ◽  
pp. 708-713 ◽  
Author(s):  
Yuan Huang ◽  
Xiu Tian Yan ◽  
Jing Yao Li
Keyword(s):  
Local Time ◽  
Job Shop ◽  
Dynamic Scheduling ◽  
Time Window ◽  
Scheduling Algorithm ◽  
Resource Constrained ◽  
Dynamic Disturbance ◽  
Scheduling System ◽  
Scheduling Method ◽  
Disturbance Analysis

To solve the Dual Resource Constrained Job Shop Dynamic Scheduling Problem with heterogeneous workers (DRCJDSP-HW),a three-tier dynamic scheduling system including dynamic disturbance analysis, dynamic disturbance evaluation and dynamic scheduling method was constructed based on the idea of scheduling with local time window. To minimize the revision of old scheduling scheme in DRCJDSP-HW, a hybrid dynamic scheduling algorithm was proposed based on the chromosome reduction mechanism and the scheduling optimization of local job in stages. The outstanding application effect of the dynamic scheduling system and the hybrid dynamic scheduling algorithm were validated reducing the influence of dynamic disturbances effectively by simulation experiment at last.

scholarly journals Driver Lane-Changing Behavior Prediction Based on Deep Learning

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Cheng Wei ◽  
Fei Hui ◽  
Asad J. Khattak
Keyword(s):  
Neural Network ◽  
Prediction Model ◽  
Traffic Safety ◽  
Prediction Models ◽  
Time Window ◽  
Driving Safety ◽  
Physiological Data ◽  
Lane Changing ◽  
Proposed Model ◽  
Neural Network Prediction

A correct lane-changing plays a crucial role in traffic safety. Predicting the lane-changing behavior of a driver can improve the driving safety significantly. In this paper, a hybrid neural network prediction model based on recurrent neural network (RNN) and fully connected neural network (FC) is proposed to predict lane-changing behavior accurately and improve the prospective time of prediction. The dynamic time window is proposed to extract the lane-changing features which include driver physiological data, vehicle kinematics data, and driver kinematics data. The effectiveness of the proposed model is validated through the experiments in real traffic scenarios. Besides, the proposed model is compared with five prediction models, and the results show that the proposed prediction model can effectively predict the lane-changing behavior more accurate and earlier than the other models. The proposed model achieves the prediction accuracy of 93.5% and improves the prospective time of prediction by about 2.1 s on average.

scholarly journals On the correction of processed historical rainfall data of siphoned rainfall recorders

Időjárás ◽  
2021 ◽  
Vol 125 (3) ◽  
pp. 513-519
Author(s):  
Tibor Rácz
Keyword(s):  
Rainfall Intensity ◽  
Time Window ◽  
Rainfall Data ◽  
Physical Parameters ◽  
Time Interval ◽  
Data Correction ◽  
Counting Error ◽  
Measurement Results ◽  
Average Rainfall ◽  
Intensity Duration Frequency

Historical rainfall data registered by siphoned rainfall recorder (SRW) devices have been widely used for a long time in rainfall intensity investigations. A relatively known counting error of the SRW devices is the siphoning error, when the registration of rainfall is blocked temporarily, during the drainage of measure tank. This issue causes a systematic underestimation in the rainfall and rainfall intensity measurement results. To reduce its consequences, a data correction is crucial when SRW data are used, for example as a reference for climate comparison studies, or for proceeding of intensity-duration-frequency curves, etc. In this paper, a formula is presented to fix the siphonage error of SRW devices for historical rainfall data. The early measures were processed in a significant percentage of cases, and sometimes the original measurement results (registration ribbon) have been lost. An essential advantage of the presented formula is that it can be applied for these processed data, which show only the intensity of a known length time interval. For this correction, the average rainfall intensity and the length of the time window are needed, over the physical parameters of the SRW device. The data correction can provide a fixed value of the rainfall intensity, which is undoubtedly closer to the real average rainfall intensity. The importance of this formula is in the reprocessing and validation of the historical rainfall intensity data, measured by siphoned rainfall recorders.

A Two-Phase Scheduling Method Combined to the Tabu Search for the DARP

2014 ◽  
Vol 5 (2) ◽  
pp. 1-21 ◽  
Author(s):  
Ali Lemouari ◽  
Oualid Guemri
Keyword(s):  
Tabu Search ◽  
Time Window ◽  
Total Duration ◽  
Two Phase ◽  
Transportation Services ◽  
Delivery Problem ◽  
Pickup And Delivery Problem ◽  
Early Arrival ◽  
Scheduling Method ◽  
Transportation Applications

The dial-a-ride problem (DARP), is a variant of the pickup and delivery problem (PDP), consists of designing vehicle routes of n customers transportation requests. The problem arises in many transportation applications, like door-to-door transportation services for elderly and disabled people or in services for patients. This paper consider a static multivehicle DARP, which the objective is to minimize a combined costs of total travel distance, total duration, passengers waiting time, the excess ride time of customers, and the early arrival time while respecting maximum route duration limit, the maximum costumer ride time limit, the capacity and the time window constraint. The authors propose a two-phase scheduling method combined to the tabu search heuristic, for the static multivehicle DARP. Their experimentation report best results for Cordeau Benchmark test problem, compared to reported results.

On querying historical k-cores

2021 ◽  
Vol 14 (11) ◽  
pp. 2033-2045
Author(s):  
Michael Yu ◽  
Dong Wen ◽  
Lu Qin ◽  
Ying Zhang ◽  
Wenjie Zhang ◽  
...  
Keyword(s):  
Real World ◽  
Time Window ◽  
Simple Graph ◽  
Time Interval ◽  
Research Attention ◽  
High Effectiveness ◽  
Running Time ◽  
Temporal Graphs ◽  
Index Size ◽  
Novel Algorithm

Many real-world relationships between entities can be modeled as temporal graphs, where each edge is associated with a timestamp or a time interval representing its occurrence. K -core is a fundamental model used to capture cohesive subgraphs in a simple graph and have drawn much research attention over the last decade. Despite widespread research, none of the existing works support the efficient querying of historical k -cores in temporal graphs. In this paper, given an integer k and a time window, we study the problem of computing all k -cores in the graph snapshot over the time window. We propose an index-based solution and several pruning strategies to reduce the index size. We also design a novel algorithm to construct this index, whose running time is linear to the final index size. Lastly, we conducted extensive experiments on several real-world temporal graphs to show the high effectiveness of our index-based solution.

scholarly journals Effect Analysis of Intermittent Release Measures in Heavy Fog Weather with an Improved CA Model

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jing Shi ◽  
Jinhua Tan
Keyword(s):  
Traffic Safety ◽  
Traffic Management ◽  
Traffic Accidents ◽  
Economic Losses ◽  
Time Interval ◽  
Risk Indicator ◽  
Effect Analysis ◽  
Driving Behaviors ◽  
Related Risk ◽  
Ca Model

Heavy fog may easily cause traffic accidents; thus freeway closures are frequently taken in order to ensure traffic safety in China, which not only seriously affect the travel of people, but also bring great economic losses. This paper studies the fog related risk of rear-end collisions and the intermittent release measures taken to reduce such risk; meanwhile, an improved cellular automaton model considering driving behaviors in heavy fog is proposed. The simulation results indicate that the risk indicatorfain fog is much higher than normal weather when cellular occupancyρ<0.5. After taking intermittent release measures, the magnitude offawill drop from 10−4to 10−5under the same fog condition, which greatly enhances the safety. In addition, this paper concludes the appropriate vehicle number released for each time and the time intervalhtbetween adjacent fleets and the maximum number of vehicles𝒬maxwhich can be released per hour. These results can be used as theoretical basis and reference for the traffic management departments to develop intermittent release measures.

Energy Analysis of Split Air Conditioning System Using Variable Speed Drive

2016 ◽  
Vol 819 ◽  
pp. 212-215 ◽  
Author(s):  
Affandi Mohd Nasib ◽  
Henry Nasution ◽  
Azhar Abdul Aziz ◽  
Muchamad Oktaviandri ◽  
Sumeru ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Internal Heat ◽  
Coefficient Of Performance ◽  
Maximum Speed ◽  
Time Interval ◽  
Variable Speed ◽  
Performance Measurements ◽  
Variable Speed Drive

An air conditioning (AC) system design requires two main aspects that should be taken into consideration, there are reducing energy consumption and ensuring thermal comfort. This paper present variable speed drive on compressor motor is being tested to reduce the energy consumption. Conventional AC system to use on/off controller where the compressor motor turns itself on and runs at maximum speed then turns back off to achieve the temperature setting. This controller consumes more energy, however, by using a variable speed drive, the compressor motor will constantly run at various speeds while achieving the temperature setting. A system that developed software to implement the controller algorithms was installed in a thermal environmental room with data acquisition to monitor the room temperature, energy consumption, energy saving and coefficient of performance. Measurements were taken during the one hour experimental period at a time interval of three minutes for temperature set-points of 22, 23 and 24°C with internal heat loads of 500, 700 and 1000 W. The proposed technique can save energy and thermal comfort in comparison with conventional on/off control. The experiment results indicate that the application of variable speed drive on compressor motor is better than conventional on/off.

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