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Using Simulation to Analyze Picker Blocking in Manual Order Picking systems

Procedia Manufacturing 2017年 11卷 1798-1808页

作者： Bahrami, Behnam Aghezzaf, El-Houssaine Limere, Veronique Department of Industrial Systems Engineering and Product Design Faculty of Engineering and Architecture Ghent University Gent Belgium Department of Business Informatics and Operations Management Faculty of Engineering and Architecture Ghent University Gent Belgium

The rise of the e-commerce practice makes the warehouses be confronted with ever smaller orders that must be met ever faster, often within a 24-h period. This pressures the order picking process as the orders pickers’ workload becomes higher and higher, leading subsequently to congestion in the warehouse and impacting its productivity. It is therefore crucial to determine which order batching and picking policies enhance the performance of order picking activities. This paper carries out an intensive simulation study to examine the performance of different order picking policies with batching in a wide-aisle warehouse with a low-level picker-to-parts system. The performance of the system is measured in terms of total travelled distance, number of collisions between operators (congestion) and order lead times. A full factorial design is set up and the simulation output is statistically analyzed. The results are reported and thoroughly discussed. © 2017 The Authors

关键词： Batching Congestion Order picking Simulation

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Matrix product operators for sequence to sequence learning

arXiv

引用

arXiv 2018年

作者： Guo, Chu Jie, Zhanming Lu, Wei Poletti, Dario Engineering Product Development Pillar Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Zhengzhou Information Science and Technology Institute Zhengzhou450004 China Information Systems Technology and Design Singapore University of Technology and Design 8 Somapah Road 487372 Singapore

The method of choice to study one-dimensional strongly interacting many body quantum systems is based on matrix product states and operators. Such method allows to explore the most relevant, and numerically manageable, portion of an exponentially large space. It also allows to describe accurately correlations between distant parts of a system, an important ingredient to account for the context in machine learning tasks. Here we introduce a machine learning model in which matrix product operators are trained to implement sequence to sequence prediction, i.e. given a sequence at a time step, it allows one to predict the next sequence. We then apply our algorithm to cellular automata (for which we show exact analytical solutions in terms of matrix product operators), and to nonlinear coupled maps. We show advantages of the proposed algorithm when compared to conditional random fields and bidirectional long short-term memory neural network. To highlight the exibility of the algorithm, we also show that it can readily perform classification tasks. Copyright © 2018, The Authors. All rights reserved.

关键词： Machine learning

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Considering the Difference of Pre-set Service Level and Actual Service Level in a Safety-stock Based SPIRP

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Procedia Manufacturing 2017年 11卷 1933-1939页

作者： Yadollahi, Ehsan Aghezzaf, El-Houssaine Walraevens, Joris Raa, Birger Department of Industrial Systems Engineering and Product Design and Flanders Make Ghent University Gent Belgium Department of Telecommunications and Information Processing (TELIN) Faculty of Engineering and Architecture Ghent University Gent Belgium

To deal with uncertain demand rates in stochastic periodic inventory routing problem (SPIRP), supply chain planners foresee an extra stock amount, known as “safety stock” at the retailers. This safety stock prevents stock-out from occurring and gives the supply chain planner the possibility to offer a level of service assurance to its retailers. The pre-set service level for the retailers guarantees the reliability of having the demand rates satisfied at a certain rate during the planning horizon. To prove the guaranteed service level at the retailers, the actual service level is measured through a simulation experiment. The results of the simulation show that the difference between the actual and pre-set service level does not behave linearly for the different scenarios. In addition, this non-linearity changes with the length of the planning horizon. Minimization of the difference between actual and expected service level results in saving the spent costs for the assurance of service at the retailers. In this paper, we evaluate the behavior of the actual service level compared to the pre-set service level. Also the effects on short/long term planning horizon is measured and analyzed. A case study of a distribution center is simulated to show how to optimize the inventory level and routing system with different planning horizons and pre-set service levels. © 2017 The Authors

关键词： Inventory Routing Problem Planning Horizon Safety Stock Service Level Simulation

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Shifting value stream patterns along the product lifecycle with digital twins

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Procedia CIRP 2019年 86卷 3-11页

作者： Benjamin Schleich Marc-André Dittrich Till Clausmeyer Roy Damgrave John Ahmet Erkoyuncu Benjamin Haefner Jos de Lange Denys Plakhotnik Wieben Scheidel Thorsten Wuest Engineering Design Friedrich-Alexander-Universität Erlangen-Nürnberg Martensstraße 9 91058 Erlangen Germany Institute of Production Engineering and Machine Tools (IFW) Leibniz Universität Hannover An der Universität 2 30823 Garbsen Germany Institute of Forming Technology and Lightweight Components TU Dortmund Baroper Straße 303 44227 Dortmund Germany Department of Design Production & Management Design Engineering University of Twente de Horst 2 7522 NB Enschede Netherlands School of Aerospace Transport and Manufacturing Cranfield University Cranfield Bedfordshire MK43 0AL United Kingdom Institute of Production Science (wbk) Karlsruhe Institute of Technology (KIT) Kaiserstraße 12 76131 Karlsruhe Germany ModuleWorks GmbH Henricstraße 50 52070 Aachen Germany Institute of Product Development (iPeG) Leibniz Universität Hannover Welfengarten 1a 30167 Hannover Germany Industrial and Management Systems Engineering West Virginia University Morgantown USA

The concept of digital twins promises high potentials for product design, manufacturing, user experience and recycling. Thus, digital twins have received increasing interest in academia and industry. However, the actual benefits of digital twins remain in many cases unclear. This article aims to summarize selected recent developments in this field and demonstrate use cases from different phases of the product lifecycle. For that purpose, examples from the design, manufacturing, use and recycling phase are presented. In a subsequent discussion, ideas for new value stream patterns using digital twins are envisioned and research questions are derived.

关键词： Digital twin Cyber-physical systems design Manufacturing Recycling

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Performance Analysis of TDOA-based Indoor Positioning systems using Visible LED Lights

Performance Analysis of TDOA-based Indoor Positioning System...

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IEEE International Symposium on Wireless systems (IDAACS-SWS)

作者： Aqsa Naeem Naveed Ui Hassan Muhammad Adeel Pasha Chau Yuen Axel Sikora Department of Electrical Engineering Lahore University of Management Sciences (LUMS) Lahore Pakistan Engineering Product Development Singapore University of Technology and Design (SUTD) Singapore Institute of Reliable Embedded Systems and Communication Electronics Hochschule Offenburg Germany

ISBN: (纸本)9781538675885

Recently, the demand for scalable, efficient and accurate Indoor Positioning systems (IPS) has seen a rising trend due to their utility in providing Location Based Services (LBS). Visible Light Communication (VLC) based IPS designs, VLC-IPS, leverage Light Emitting Diodes (LEDs) in indoor environments for localization. Among VLC-based designs, Time Difference of Arrival (TDOA) based techniques are shown to provide very low errors in the relative position of receivers. Our considered system consists of five LEDs that act as transmitters and a single receiver (photodiode or image sensor in smart phone) whose position coordinates in an indoor environment are to be determined. As a performance criterion, Cramer Rao Lower Bound (CRLB) is derived for range estimations and the impact of various factors, such as, LED transmission frequency, position of reference LED light, and the number of LED lights, on localization accuracy has been studied. Simulation results show that depending on the optimal values of these factors, location estimation on the order of few centimeters can be realistically achieved.

关键词： Light emitting diodes Receivers Transmitters Estimation Frequency division multiplexing IP networks Indoor environments

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Chaos and the Flow Capture Problem: Polluting is Easy, Cleaning is Hard

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Physical Review Applied 2018年第3期10卷 034055-034055页

作者： Lachlan D. Smith Guy Metcalfe Julio M. Ottino Department of Chemical and Biological Engineering Northwestern University Evanston Illinois 60208 USA Department of Mechanical and Product Design Engineering Swinburne University of Technology Hawthorn Victoria 3122 Australia Department of Mechanical Engineering Northwestern University Evanston Illinois 60208 USA The Northwestern Institute on Complex Systems (NICO) Northwestern University Evanston Illinois 60208 USA

Cleaning pollution from a heterogeneous flow environment is far from simple. We consider the flow capture problem, which has flows and sinks in a heterogeneous environment, and investigate the problem of positioning pollutant capture units. We show that arrays of capture units carry a high risk of failure without accounting for environmental heterogeneity and chaos in their placement, design, and operation. Our idealized two-dimensional models reveal salient features of the problem. Maximum capture efficiency depends on the required capture rate: long-term efficiency decreases as the number of capture units increases, whereas short-term efficiency increases. If efficiency is important, the capture process should begin as early as feasible. Knowledge of transport controlling flow structures offers predictability for unit placement. We demonstrate two heuristic approaches to near-optimally position capture units.

关键词： Atmospheric fluid dynamics Chaotic advection Climate research Environmental research Mixing in geophysical flows Turbulent mixing Chaos & nonlinear dynamics

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Preface: International conference on recent advancements in biomedical engineering - 2021

引用

Journal of Physics: Conference Series 2021年第1期2027卷

作者： Kalidoss, Ramji Aanand, J. Sundeep Kanagasabai, V. Suresh, R.M. Raju, K. Vijaya Bhaskar Vasuki, R. Kripa, N. Prasath, T. Manoj Vaidyanathan, Vijay Volanti, Diogo Paschoalini Rajan, A. Arockia Muttan, S. Pandikumar, A. Krishnan, Jithin Sivaraman, J. Gopi, Varun Alizadeh, Mahdi Shriram, Preethi Danquah-Amoah, Archibald Hari, Rajeswari Ravisankar, T.N. Venkatraman, K. Arshad, Mohd Khairuddin Md Rengan, Aravind Kumar Kavitha, A. Bandyopadhyay, Rajib Singh, Bikesh Kumar Nirala, Neelamshobha Banu, N.M. Masoodhu Manimegalai, P. Sreelatha, P. Jayalatha, K. Arockia Jayasree, T. Snekhalatha, U. Alkan, Nazlican Rajkumar, S. Christopher, David Vinayagam, N. Masi, Chandran Allasi, Haiter Lenin Muthuraman, S. Shata, Agegnehu Shara Radhakrishnan, K. Gnanavel, S. Sivakumar, P. Malathi, T. BIHER Chennai India BIST BIHER Chennai India University of North Texas United States Sao Paulo State University Brazil Indian Institute of Technology Madras India Anna University Chennai India CSIR-CECRI Karaikudi India SCTIMST Trivandrum India National Institute of Technology Rourkela India National Institute of Technology Trichy India University of Zanjan Iran Dornier Medical Tech Munich Germany All Nations University Ghana Dr. M. G. R Medical University Chennai India Sudar Hospitals Chennai India Bio Vision Medical Systems Chennai India Universiti Malaysia Perlis Malaysia Indian Institute of Technology Hyderabad India SSN Institutions Chennai India Jadavpur University Kolkata India National Institute of Technology Raipur India Vel Tech R&D Institute of Science and Technology Chennai India Karunya Institute of Technology and Sciences Coimbatore India KPR Institute of Engineering and Technology Coimbatore India SASTRA Deemed University Thanjavur India SRM Institute of Science and Technology India Product Design and Development Dornier MedTech Munich Germany Institute of Technology Hawassa University Ethiopia College of Engineering Wolaita Sodo University Ethiopia University of Technology and Applied Sciences NCT_NIZWA Sultanate Oman College of Biological and Chemical Engineering Addis Ababa Science and Technology University Addis Ababa Ethiopia Kombolcha Institute of Technology Kombolcha Ethiopia University of Technology and Applied Sciences Higher College of Technlogy Muscat Oman Arba Minch Institute of Technology Arba Minch University Ethiopia SSN Research Centre SSN Institutions Chennai India SRM Institute of Science and Technology Kattankulathur India GRT Institute of Engineering and Technology Tiruttani India Rajalakshmi Institute of Technology Chennai India

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Countering Real-Time Stream Poisoning: An Architecture for Detecting Vessel Spoofing in Streams of AIS Data

Countering Real-Time Stream Poisoning: An Architecture for D...

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IEEE International Symposium on Dependable, Autonomic and Secure Computing (DASC)

作者： Ioannis Kontopoulos Giannis Spiliopoulos Dimitrios Zissis Konstantinos Chatzikokolakis Alexander Artikis Department of Product and Systems Design Engineering University of the Aegean Syros Greece MarineTraffic United Kingdom Department of Informatics and Telematics Harokopio University Athens Greece Institute of Informatics & Telecommunications National Centre for Scientific Research (NCSR) Demokritos Athens Greece

ISBN: (纸本)9781538675199

Well poisoning is an ancient war stratagem which was frequently used as a "scorched earth tactic". Today this tactic has been adapted by malicious attackers to the digital world and evolved into "stream poisoning", in which corrupt or fallacious data is injected into a data lake, so as to corrupt the integrity of the information stored there. Numerous maritime surveillance systems nowadays rely on the Automatic Identification System (AIS), which is compulsory for vessels over 299 Gross Tones, for vessel tracking purposes. Ship AIS spoofing involves creating a nonexistent vessel or masquerading a vessel's true identity, resulting in hiding or transmitting false positional data, so that a vessel appears to behave legitimately, thus deceiving stakeholders and authorities. Due to the volume and velocity of data received traditional approaches fail to automatically detect these spoofing events in real time. We focus on an industrial use case of detecting spoofing events in AIS streams and validate our approach in real world conditions.

关键词： Artificial intelligence Real-time systems Radar tracking Trajectory Distributed databases Big Data Surveillance

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Hybrid quantum-classical convolutional neural networks

arXiv

引用

arXiv 2019年

作者： Liu, Junhua Lim, Kwan Hui Wood, Kristin L. Huang, Wei Guo, Chu Huang, He-Liang Information Systems Technology and Design Singapore University of Technology and Design 8 Somapah Road 487372 Singapore SUTD-MIT International Design Center Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Engineering Product Develoment Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Guangxi Key Laboratory of Optoelectronic Information Processing Guilin University of Electronic Technology Guilin541004 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China Hefei National Laboratory for Physical Sciences at Microscale Department of Modern Physics University of Science and Technology of China Anhui Hefei230026 China Shanghai Branch Cas Ctr. for Excellence and Synergetic Innovation Centre in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei201315 China Henan Key Laboratory of Quantum Information and Cryptography Henan Zhengzhou450000 China

Deep learning has been shown to be able to recognize data patterns better than humans in specific circumstances or contexts. In parallel, quantum computing has demonstrated to be able to output complex wave functions with a few number of gate operations, which could generate distributions that are hard for a classical computer to produce. Here we propose a hybrid quantum-classical convolutional neural network (QCCNN), inspired by convolutional neural networks (CNNs) but adapted to quantum computing to enhance the feature mapping process. QCCNN is friendly to currently noisy intermediate-scale quantum computers, in terms of both number of qubits as well as circuit's depths, while retaining important features of classical CNN, such as nonlinearity and scalability. We also present a framework to automatically compute the gradients of hybrid quantum-classical loss functions which could be directly applied to other hybrid quantum-classical algorithms. We demonstrate the potential of this architecture by applying it to a Tetris dataset, and show that QCCNN can accomplish classification tasks with learning accuracy surpassing that of classical CNN. Copyright © 2019, The Authors. All rights reserved.

关键词： Convolution

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A Statistical Comparison of Two Safety Stock Replenishment Mechanisms in a Cyclic Stochastic IRP

引用

IFAC-PapersOnLine 2016年第12期49卷 1508-1513页

作者： Yadollahi, Ehsan Aghezzaf, El-Houssaine Raa, Birger Department of Industrial Systems Engineering and Product Design Faculty of Engineering and Architecture Ghent University Gent Belgium

Preventing stock-out in a replenishment system, in which customer demand rates are stochastic with constant averages, can be accomplished via safety stocks hold at each customer. These safety stocks should be replenished back to their initial levels each time they are used. However, sometimes it occurs that a truck does not have enough capacity to carry the amount of the product the visited customers need to restore their stocks and safety stocks to their required levels. Therefore, the carried extra amount of the product, intended to replenish safety stocks, should be divided amongst the customers in some optimal or fair manner. To achieve this fair allocation, we propose and analyze two policies, the first called Fair-share and the second Ratio methods. Details on how these two methods are implemented, to achieve the level of service expected at each customer, are discussed and illustrated. In addition a simulation model is developed and used to compare the performance of each policy in the long run. © 2016

关键词： Sales Stochastic systems Backlog Fair share Inventory routing problems Safety stock Service levels Simulation

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