scholarly journals The Influence of Yard Trucks on Berth Operations in Smaller Container Terminals

Pomorstvo ◽  
2019 ◽  
Vol 33 (2) ◽  
pp. 171-175
Author(s):  
Maja Stojaković ◽  
Elen Twrdy
Keyword(s):  
Waiting Times ◽  
Container Terminals ◽  
Extreme Pressure ◽  
Simulation Approach ◽  
Horizontal Transport ◽  
Good Level ◽  
Quay Cranes ◽  
Pressure Form

Nowadays smaller container terminals are facing an increase in traffic and ship sizes and are consequently subject to extreme pressure form ship-owners that require rapid and efficient transhipment operations in the port, the achievement of which is only possible with the assignment of the proper type and number of quay cranes to each ship and with a good level of synergy between the cranes and the transfer mechanisation. The latter has a significant impact on the cranes working and waiting times and affects the entirety of berth operations. Existing terminals that cannot afford to invest in new modern horizontal transport technologies are most commonly using yard trucks that provide less efficient port transfer operations. That is why in the paper a simulation approach has been used in order to determine how a different number of yard trucks assigned to a single quay crane can affect the productivity of that crane and the productivity of the whole berth subsystem.

scholarly journals Multiple quay cranes scheduling for double cycling in container terminals

PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0180370 ◽  
Author(s):  
Yanling Chu ◽  
Xiaoju Zhang ◽  
Zhongzhen Yang
Keyword(s):  
Container Terminals ◽  
Quay Cranes ◽  
Double Cycling

scholarly journals OPTIMASI SISTEM ANTRIAN PADA LAYANAN KESEHATAN MASYARAKAT MENGGUNAKAN PENDEKATAN SIMULASI

2019 ◽  
Vol 3 (1) ◽  
pp. 14-22
Author(s):  
Widya Setia Findari ◽  
Yohanes Anton Nugroho
Keyword(s):  
Waiting Time ◽  
Six Sigma ◽  
Waiting Times ◽  
Community Health Center ◽  
Observation Data ◽  
Simulation Approach ◽  
Simulation Test ◽  
Queue System ◽  
Number Of Patients ◽  
Patient Service

Abstract : The purpose of this study is to optimize service time in a community health center. The average number of patients visiting is 100 to 300 per day. In certain units there is a heavy queue of patients which increases service waiting times, including registration units, inspection units, and pharmaceutical units. The initial observation data on the existing system shows the waiting time for patient services is 2,7 hours. This fact shows that the time of patient service on the existing system needs to be optimized so that the waiting time can be accelerated. This study offers a solution to optimize the service queue system using a simulation approach. The DMAIC (Define, Measure, Analyze, Improve, Control) Six Sigma method is used as a basis for analyzing the waiting time for services from an existing system. The results of the analysis are used in the simulation test to obtain improvement factors using several scenarios. The best simulation results are obtained with the scenario of adding operators in all units. Optimizing the waiting time of patient services using the best scenario simulation approach is shown by the decrease in waiting time of the queue system by 1,05 hours or 38,9% faster than the existing system.Keywords: System Optimizing; Public Health; Queue; Simulation; DMAIC Six SigmaAbstrak : Tujuan penelitian ini adalah untuk mengoptimalkan waktu tunggu pelayanan di sebuah pusat kesehatan masyarakat (Puskesmas). Rata-rata jumlah pasien yang berkunjung adalah 100 hingga 300 per hari. Pada beberapa unit tertentu terjadi antrian pasien yang padat sehingga meningkatkan waktu tunggu pelayanan, antara lain unit pendaftaran, unit pemeriksaan, dan unit farmasi. Data pengamatan awal pada sistem yang ada menunjukkan waktu tunggu pelayanan pasien adalah 2,7 jam. Fakta ini menunjukkan bahwa waktu pelayanan pasien pada sistem yang ada perlu dioptimalkan agar waktu tunggu dapat dipercepat. Penelitian ini menawarkan solusi optimalisasi sistem antrian pelayanan dengan menggunakan pendekatan simulasi. Metode DMAIC (Define, Measure, Analyze, Improve, Control) Six Sigma digunakan sebagai dasar analisis waktu tunggu pelayanan dari sistem yang sudah ada. Hasil analisis digunakan pada uji simulasi untuk mendapatkan faktor perbaikan dengan menggunakan beberapa skenario. Hasil simulasi terbaik diperoleh dengan skenario penambahan operator di semua unit. Optimasi waktu tunggu pelayanan pasien dengan menggunakan pendekatan simulasi skenario terbaik ditunjukkan oleh penurunan waktu tunggu sistem antrian sebesar 1,05 jam atau 38,9% lebih cepat dari sistem yang sudah ada.Kata kunci: Optimasi Sistem, Layanan Kesehatan, Antrian, Simulasi, DMAIC Six Sigma

Priority-based speed control strategy for automated guided vehicle path planning in automated container terminals

2020 ◽  
Vol 42 (16) ◽  
pp. 3079-3090 ◽  
Author(s):  
Meisu Zhong ◽  
Yongsheng Yang ◽  
Shu Sun ◽  
Yamin Zhou ◽  
Octavian Postolache ◽  
...  
Keyword(s):  
Path Planning ◽  
Control Strategy ◽  
Search Algorithm ◽  
Waiting Times ◽  
Optimal Path ◽  
Speed Control ◽  
Container Terminals ◽  
Automated Guided Vehicles ◽  
Operating Efficiency ◽  
Continuous Increase

With the continuous increase in labour costs and the demands of the supply chain, improving the efficiency of automated container terminals has been a key factor in the development of ports. Automated guided vehicles (AGVs) are the main means of horizontal transport in such terminals, and problems in relation to their use such as vehicle conflict, congestion and waiting times have become very serious, greatly reducing the operating efficiency of the terminals. In this article, we model the minimum driving distance of AGVs that transport containers between quay cranes (QCs) and yard cranes (YCs). AGVs are able to choose the optimal path from pre-planned paths by testing the overlap rate and the conflict time. To achieve conflict-free AGV path planning, a priority-based speed control strategy is used in conjunction with the Dijkstra depth-first search algorithm to solve the model. The simulation experiments show that this model can effectively reduce the probability of AGVs coming into conflict, reduce the time QCs and YCs have to wait for their next task and improve the operational efficiency of AGV horizontal transportation in automated container terminals.

Two-level simulation approach to evaluate the performance of autonomous wheelchairs in a hospital

SIMULATION ◽  
2020 ◽  
Vol 96 (10) ◽  
pp. 781-789
Author(s):  
Iván Castilla-Rodríguez ◽  
Rafael Arnay ◽  
Raquel Rodríguez ◽  
Jonel Rodríguez
Keyword(s):  
Waiting Times ◽  
Physical World ◽  
Simulation Approach ◽  
Economic Implications ◽  
Hospital Resources ◽  
Real Robot ◽  
Transportation Times ◽  
Sensor Configuration ◽  
High Level

In this paper, we present the combined usage of two different simulation levels to evaluate the economic and quality-of-service impact of deploying a fleet of autonomous wheelchairs in a hospital. The first simulation level deals with the physical world and takes into account the characteristics of a real robot, such as dimensions, sensor configuration, and speed. We simulate different trajectories in order to obtain realistic transportation times that are subsequently used in the high-level simulation. This high-level simulation considers those hospital resources that are affected by the inclusion of automated wheelchairs, and computes the economic implications of partially or totally substituting the current fleet of manual wheelchairs. Our results show that switching to automated wheelchairs may be beneficial in terms not only of reduced waiting times for patients, but also of economic savings.

Approximation algorithm for uniform quay crane scheduling at container ports

2016 ◽  
Vol 08 (02) ◽  
pp. 1650018 ◽  
Author(s):  
Ming Liu ◽  
Feifeng Zheng ◽  
Yinfeng Xu ◽  
Chengbin Chu
Keyword(s):  
Approximation Algorithm ◽  
Container Terminals ◽  
Container Port ◽  
Quay Crane Scheduling ◽  
Processing Efficiency ◽  
Crane Scheduling ◽  
Quay Cranes ◽  
Container Ports ◽  
Loading And Unloading ◽  
Turn Around Time

At a container port, container vessels are served by quay cranes for loading and unloading containers. Each vessel is typically split into bays from head to tail where containers are stored. Parallel quay cranes can process different bays simultaneously, and their processing efficiency significantly affects the turn-around time of a container vessel. Sharing a single traveling rail, the quay cranes cannot crossover each other, and this phenomenon is referred as the non-crossing constraint. In addition, the quay cranes may have different processing speeds due to gradual equipment updates. Inspired by updating activities of cranes in modern container terminals, this paper studies a scheduling problem with two uniform quay cranes, aiming at minimizing the turn-around time of a vessel, i.e., the makespan. We mainly develop an integrated approximation algorithm which is [Formula: see text]-approximation, where the two quay cranes are of processing speeds 1 and [Formula: see text], respectively.

A New Dispatching Model of Automated Lifting Vehicles in Automated Container Terminal with Limited Buffer Space

2013 ◽  
Vol 446-447 ◽  
pp. 1334-1339 ◽  
Author(s):  
Seyed Hamidreza Sadeghian ◽  
Mohd Khairol Anuar Bin Mohd Ariffin ◽  
Say Hong Tang ◽  
Napsiah Binti Ismail
Keyword(s):  
Programming Model ◽  
Container Terminal ◽  
Container Terminals ◽  
Mixed Integer ◽  
Transport Systems ◽  
Buffer Space ◽  
Integrated Scheduling ◽  
Quay Cranes ◽  
Automated Lifting Vehicle ◽  
Large Container

Automation of the processes at the quays of the world's large container ports is one of the answers to the required ever-increasing transshipment volumes within the same timeframe. For such purpose, using new generation of vehicles is unavoidable. One of the automatic vehicles that can be used in container terminals is Automated Lifting Vehicle (ALV). Integrated scheduling of handling equipments with quay cranes can increase the efficiency of automated transport systems in container. In this paper, an integrated scheduling of quay cranes and automated lifting vehicles with limited buffer space is formulated as a mixed integer linear programming model. This model minimizes the makespan of all the loading and unloading tasks for a pre-defined set of cranes in a scheduling problem.

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