scholarly journals Simulation-Based Assessment of Parking Constraints for Automated Mobility on Demand: A Case Study of Zurich

Vehicles ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 272-286
Author(s):  
Claudio Ruch ◽  
Roman Ehrler ◽  
Sebastian Hörl ◽  
Milos Balac ◽  
Emilio Frazzoli
Keyword(s):  
Customer Service ◽  
Waiting Times ◽  
Service Level ◽  
Demand System ◽  
Future Research ◽  
Parking Space ◽  
On Demand ◽  
System A ◽  
Customer Service Level ◽  
Simulation Based

In a coordinated mobility-on-demand system, a fleet of vehicles is controlled by a central unit and serves transportation requests in an on-demand fashion. An emerging field of research aims at finding the best way to operate these systems given certain targets, e.g., customer service level or the minimization of fleet distance. In this work, we introduce a new element of fleet operation: the assignment of idle vehicles to a limited set of parking spots. We present two different parking operating policies governing this process and then evaluate them individually and together on different parking space distributions. We show that even for a highly restricted number of available parking spaces, the system can perform quite well, even though the total fleet distance is increased by 20% and waiting time by 10%. With only one parking space available per vehicle, the waiting times can be reduced by 30% with 20% increase in total fleet distance. Our findings suggest that increasing the parking capacity beyond one parking space per vehicle does not bring additional benefits. Finally, we also highlight possible directions for future research such as to find the best distribution of parking spaces for a given mobility-on-demand system and city.

scholarly journals Integrating Mathematical and Simulation Approach for Optimizing Production and Distribution Planning With Lateral Transshipment in a Supply Chain

2022 ◽  
Vol 15 (1) ◽  
pp. 0-0
Keyword(s):  
Supply Chain ◽  
Customer Service ◽  
Optimal Solution ◽  
Integrated Approach ◽  
Service Level ◽  
Computational Time ◽  
Customer Service Level ◽  
Simulation Based ◽  
Production And Distribution ◽  
Lateral Transshipment

Supply chain planning aims to maximize the chain's profit and find an effective way to integrate production and distribution. A mathematical and simulation-based optimizations are two common disciplines in which this study integrates both of them together to consolidate their advantages. A mathematical model is formulated to find an optimal production-distribution plan. Then, the result is fed into a simulation model operating under uncertainty to verify the feasibility of the plan. Our integrated approach tries to find a feasible plan that satisfies both required customer service level and makespan limitation where safety stock is used to hedge against uncertainties, and lateral transshipment is used for emergency measures against excessive fluctuation of customer demand. A case study that optimizes the profit of an entire chain is used to demonstrate the algorithm. The outcomes of the study show that our proposed approach can yield feasible results (with near or even optimal solution) with much faster computational time as compared to the traditional simulation-based optimization.

What should be lean buffer threshold for the forward-reserve warehouse?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bhavin Shah
Keyword(s):  
Mathematical Model ◽  
Customer Service ◽  
Value Added ◽  
Service Level ◽  
Buffer Size ◽  
Value Stream Mapping ◽  
Content Type ◽  
Customer Service Level ◽  
The Impact ◽  
Just Right

PurposeThe assorted piece-wise retail orders in a cosmetics warehouse are fulfilled through a separate fast-picking area called Forward Buffer (FB). This study determines “just-right” size of FB to ensure desired Customer Service Level (CSL) at least storage wastages. It also investigates the impact of FB capacity and demand variations on FB leanness.Design/methodology/approachA Value Stream Mapping (VSM) tool is applied to analyse the warehouse activities and mathematical model is implemented in MATLAB to quantify the leanness at desired CSL. A comprehensive framework is developed to determine lean FB buffer size for a Retail Distribution Centre (RDC) of a cosmetics industry.FindingsThe CSL increases monotonically; however, the results concerning spent efforts towards CSL improvement gets diminished with raised demand variances. The desired CSL can be achieved at least FB capacity and fewer Storage Waste (SW) as it shifts towards more lean system regime. It is not possible to improve Value Added (VA) time beyond certain constraints and therefore, it is recommended to reduce Non-Value Added (NVA) order processing activities to improve leanness.Research limitations/implicationsThis study determines “just-right” capacity and investigates the impact of buffer and demand variations on leanness. It helps managers to analyse warehouse processes and design customized distribution policies in food, beverage and retail grocery warehouse.Practical implicationsProposed buffering model offers customized strategies beyond pre-set CSL by varying it dynamically to reduce wastages. The mathematical model deriving lean sizing and mitigation guidelines are constructive development for managers.Originality/valueThis research provides an inventive approach of VSM model and Mathematical algorithm endorsing lean thinking to design effective buffering policies in a forward warehouse.

scholarly journals A literature review on multi-echelon inventory management: the case of pharmaceutical supply chain

2018 ◽  
Vol 200 ◽  
pp. 00013 ◽  
Author(s):  
Nouçaiba Sbai ◽  
Abdelaziz Berrado
Keyword(s):  
Supply Chain ◽  
Customer Service ◽  
Inventory Management ◽  
Raw Materials ◽  
Integrated Approach ◽  
Service Level ◽  
Pharmaceutical Products ◽  
Management Problem ◽  
Pharmaceutical Supply Chain ◽  
Customer Service Level

Inventory management remains a key challenge in supply chain management. Many companies recognize the benefits of a good inventory management system. An effective inventory management helps reaching a high customer service level while dealing with demand variability. In a complex supply chain network where inventories are found across the entire system as raw materials or finished products, the need for an integrated approach for managing inventory had become crucial. Modelling the system as a multi-echelon inventory system allows to consider all the factors related to inventory optimization. On the other hand, the high criticality of the pharmaceutical products makes the need for a sophisticated supply chain inventory management essential. The implementation of the multi-echelon inventory management in such supply chains helps keeping the stock of pharmaceutical products available at the different installations. This paper provides an insight into the multi-echelon inventory management problem, especially in the pharmaceutical supply chain. A classification of several multi-echelon inventory systems according to a set of criteria is provided. A synthesis of multiple multi-echelon pharmaceutical supply chain problems is elaborated.

scholarly journals Multi-objective optimization model of waste tire recycling network

2020 ◽  
Vol 214 ◽  
pp. 03052
Author(s):  
Bin Wang ◽  
HeHua Li
Keyword(s):  
Environmental Protection ◽  
Customer Service ◽  
Service Level ◽  
Decision Variable ◽  
Multi Objective ◽  
Waste Tire ◽  
Multi Objective Programming ◽  
Customer Service Level ◽  
Logistics Enterprises ◽  
Waste Tire Recycling

To achieve sustainable development, logistics enterprises need not only to reduce costs, but also to save energy for environmental protection and improve customer service level. The improvement of reverse logistics management level of waste tires is of great significance to improve the efficiency of the automobile industry. In this paper, multi-objective programming is adopted to establish the waste tire recycling network model. The decision variable is whether the network nodes are set or not, the traffic flow between nodes. Constraints include meeting customer demand, balance of flow in and out of logistics nodes, etc. The model is solved by ε- constraint. Taking the actual data of the enterprise as an example, the operation results show that the operation cost, carbon emission and customer transportation distance can get an consistence within a certain range. Waste tire logistics enterprises can realize the simultaneous improvement of profit, environmental protection and customer service level.

scholarly journals A framework for designing backroom areas in grocery stores

2017 ◽  
Vol 45 (3) ◽  
pp. 230-252 ◽  
Author(s):  
Maria Pires ◽  
Joaquim Pratas ◽  
Jorge Liz ◽  
Pedro Amorim
Keyword(s):  
Customer Service ◽  
Methodological Approach ◽  
Service Level ◽  
Grocery Stores ◽  
Content Type ◽  
Customer Service Level ◽  
Storage Area ◽  
Research Stream ◽  
Retail Grocery

Purpose The design of retail backroom storage areas has great impact on in-store operations, customer service level and on store life-cycle costs. Moreover, backroom storage in modern retail grocery stores is critical to several functions, such as acting as a buffer against strong demand lifts yielded by an ever-increasing promotional activity, stocking seasonal peak demand and accommodating e-commerce activities. The purpose of this paper is to propose a framework to design retail backroom storage area. Furthermore, the authors aim to draw attention to the lack of literature on this topic, while clarifying the relationship between this promising research stream and the considerable body of research regarding the design and operations of conventional warehouses, as well as retail in-store operations. Design/methodology/approach The key literature on backrooms, grocery retail, in-store operations, warehouse design and operations was reviewed. This allowed an understanding of the gap in the literature regarding the design of backrooms. Moreover, a case study methodological approach was conducted in a Portuguese retailer to extend the literature review. Findings Despite having functions similar to conventional warehouses, backroom storage facilities have particularities that deserve a distinct analysis. Thus, the authors stress these differences and demonstrate how they influence the development of a novel backroom design framework. Originality/value This paper fills a gap by proposing a framework to design backroom areas. Furthermore, this research may help practitioners to better design backroom areas, since this process currently lacks a formal and standardized procedure.

scholarly journals Analisis Pengendalian Persediaan Obat Dengan Metode ABC, VEN dan EOQ di Rumah Sakit Bhayangkara Kediri

2020 ◽  
Vol 5 (2) ◽  
pp. 97
Author(s):  
Abdul Rofiq ◽  
Oetari Oetari ◽  
Gunawan Pamudji Widodo
Keyword(s):  
Customer Service ◽  
Maximum Level ◽  
Service Level ◽  
Safety Stock ◽  
Reorder Point ◽  
Customer Service Level ◽  
Turn Over

<p><strong>A</strong><strong>bstrak</strong><strong>: </strong>Pengelolaan persediaan obat yang optimal memberikan penghematan biaya pengadaan obat. Dua permasalahan sangat penting dalam pengendalian persediaan obat yaitu memutuskan jenis dan jumlah obat yang harus dipesan. Untuk mendapatkan solusi pengendalian persediaan maka diperlukan identifikasi dan analisis permasalahan tersebut. Tujuan penelitian ini menganalisis sistem pengendalian dan meningkatkan efisiensi siklus pengelolaan obat pasien BPJS Kesehatan klasifikasi AE di Instalasi Farmasi Rumah Sakit Bhayangkara Kediri. Obat klasifikasi AE menggambarkan obat dengan indek kritis tinggi dengan pemakaian dan <em>item</em> banyak, selanjutnya dianalisis menggunakan metode ABC, VEN dan EOQ. Jenis penelitian ini adalah penelitian deskriptif analitik, pengambilan data dilakukan secara retrospektif. Data yang digunakan obat pasien BPJS Kesehatan di Instalasi Farmasi Rumah Sakit Bhayangkara Kediri periode Januari - Desember 2018. Pengumpulan data primer dan sekunder melalui observasi dokumen di lapangan dan wawancara dengan pihak terkait. Analisis menggunakan metode ABC, VEN dan EOQ untuk klasifikasi obat AE. Selanjutnya hasil pengolahan data dibandingkan dengan parameter <em>Reorder Point</em>, <em>Inventory Value</em>, <em>Inventory Turn Over Ratio</em>, <em>Customer Service Level</em>, <em>Safety Stock</em> dan <em>Maximum level inventory</em> untuk menilai efisiensi pengendalian persediaan guna memperoleh persediaan obat yang efisien. Penelitian ini diperoleh hasil analisis pengendalian obat pasien BPJS Kesehatan menggunakan metode ABC dan VEN mampu meningkatkan pengelolaan obat menjadi efektif dan efisien khususnya obat katagori AE. Data perencanaan, pengadaan dan pemakaian obat pasien BPJS Kesehatan tahun 2018 dianalisis dengan metode EOQ selanjutnya dibandingkan nilai parameter yang digunakan dapat mengurangi nilai <em>Stock Out</em>, tetapi efektifitas dan efisiensi pengendalian obat tidak tercapai.</p>

scholarly journals Adaptive inventory control system for material items with continuous non-stationary demand

2014 ◽  
Vol 5 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Martin Krajčovič ◽  
Dariusz Plinta
Keyword(s):  
Control System ◽  
Inventory Control ◽  
Customer Service ◽  
Service Level ◽  
Inventory Systems ◽  
Inventory Level ◽  
Inventory Analysis ◽  
Software Module ◽  
Large Numbers ◽  
Customer Service Level

Abstract This paper describes an algorithm of dynamic inventory control system for large numbers of material items with continuous non-stationary demand. It uses principles of pull inventory control systems, statistical inventory analysis and joint replenishment inventory systems. This algorithm was processed in software module (VBA for Excel) and applied in practice. The target of described algorithm is to keep an optimum inventory level and optimum customer service level in terms of inventory control of items with non-stationary demand.

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