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In an intelligent distribution warehouse, latent AGVs are used for horizontal handling, and forklift AGVs are used for horizontal or vertical handling. Studying the path planning and task assignment problem when the two types of AGVs are mixed can help improve the warehouse operation efficiency and reduce the warehouse operation cost. This paper proposes a two-stage optimization method to solve this problem. In the first stage, the warehouse plan layout is transformed into a raster map, and the shortest path between any two points of the warehouse without conflict with fixed obstacles is planned and stored using the A* algorithm combined with circular rules, and the planned shortest path is called directly in the subsequent stages. In the second stage, to minimize the task completion time and AGV energy consumption, a genetic algorithm combining penalty functions is used to assign horizontal handling tasks to submerged AGVs or forklift AGVs and vertical handling tasks to forklift AGVs. The experimental results show that the method can meet the 24 h operation requirements of an intelligent distribution warehouse and realize the path planning and task assignment of forklift AGVs and latent AGVs. And furthermore, the number of AGVs arranged in the warehouse can be further reduced.

Distribution warehouses are a key element in competitive supply chains. However, although there is a growing need to reduce waste and non-value-adding activities to increase warehouse performance, insufficient research exists examining how warehouse managers can reduce operational waste in warehouse operations. To address these challenges, this article aims to validate a multi-method optimization approach for identifying and reducing operational waste in distribution warehouses. The approach integrates a unified modelling language activities diagram, system thinking method, value stream mapping, and Genba Shikumi, i.e., a quantitative tool based on successive correlation vectors and matrices, among other methods. Qualitative and quantitative information was used to validate the approach through an exploratory case study in Denmark. The significant research findings showed that the implemented approach is able to identify and prioritise the primary wastes in distribution warehouse operations. Furthermore, the study shows that the warehouse lead time could be reduced by 41.4% and the total value-added time by 81.5%, thus improving warehouse performance. Overall, the paper contributes to advancing knowledge and research on reducing operational waste in distribution warehouses by implementing an approach that helps companies identify and quantify the impact of non-value-adding activities. Lastly, findings suggest that the approach implemented could be applied in other similar contexts to identify and reduce waste to increase the performance of distribution warehouse operations.

V našem okolju se vse pogosteje pojavljajo naravne, radiološke, kemijske in biološke nesreče. V zadnjem obdobju je tudi vedno več odkritih neeksplodiranih ubojnih sredstev. Civilna zaščita je organizirana enota, ki spada pod del sistema varovanja pred naravnimi ter ostalimi nesrečami oziroma posebna enota organiziranih sil za zaščito, reševanje in pomoč. Regijski logistični center civilne zaščite Celje je del Civilne zaščite, ki ima naloge skladiščenja, vzdrževanja in razdeljevanja tehnično materialnih sredstev za zaščito in reševanje ob naravnih in drugih nesrečah. Poleg tega skrbi tudi za zbiranje, skladiščenje in razdeljevanje humanitarne pomoči v primeru množičnih nesreč. Nadalje organizira tudi mednarodno humanitarno in drugo pomoč ter poskrbi za postavitev začasnih bivališč. Zato ustrezno pozicioniranje tehnično materialnih sredstev lahko prihrani čas pri izdajanju sredstev iz regijskega logističnega centra. V diplomski nalogi je predstavljen regijski logistični center Civilne zaščite Celje z vsemi svojimi zadolžitvami, aktivnostmi in logističnimi procesi. Predstavljeno je tudi aktualno pozicioniranje tehnično materialnih sredstev v njem. V nadaljevanju diplomske naloge sem analiziral morebitno izboljšavo pozicioniranja prevzema izdelkov iz skladišča v primeru implementacije metode uskladiščenja glede na frekvenco pobiranj iz skladišča, ter prednosti komisioniranja celotnega naročila v enem ciklu. Natural, radiological, chemical and biological disasters are increasingly occurring in our environment. There has also been a recent increase in the detection of unexploded ordnance. Civil protection is an organized unit that is part of the system for protection against natural and other disasters, or a special unit of organized forces for protection, rescue and relief. The Celje Regional Logistics Center for Civil Protection is part of Civil Protection, which has the task of storing, maintaining and distributing technical material for protection and rescue in the event of natural and other disasters. In addition, it also manages the collection, storage and distribution of humanitarian aid in case of mass disasters. Providing international humanitarian and other assistance and arranging temporary accommodation is one of the key functions as well. Therefore, proper positioning of technical material is essential to save time when issuing funds from a regional logistics centre. This undergraduate thesis presents the Celje Regional Logistics Center of Civil Protection with all its tasks, activities and logistical processes. The current positioning of technical material within the center is also presented. Moreover, I have analyzed a possible improvement of how to distribute products from the warehouse more effectively by implementing a storage method according to the frequency of collection from the warehouse and the advantages of commissioning the entire order in one cycle.

В статье рассмотрены методы определения расположения распределительного склада. Решена задача поиска оптимального расположения распределительного склада путем минимизации транспортных затрат. Methods for determining the location of the distribution warehouse in the article are considered. The problem of finding the optimal location of the distribution warehouse is solved by minimizing transport costs.

Syfte – Studien syftar på att identifiera en användbar metod för att beräkna fyllnadsgrad i distributionslager samt undersöka hur visualisering av lagerfyllnadsgraden påverkar lagerplaneringens operativa arbete. För att uppnå studiens syfte har fyra frågeställningar formulerats: Vilka parametrar behövs för att beräkna fyllnadsgraden för klämgods i ett distributionslager? Vilken praktiskt användbar metod kan användas för att beräkna fyllnadsgraden för klämgods i ett distributionslager? Hur kan de framtagna parametrarna sammanställas för att kunna visualisera aktuell fyllnadsgrad? Hur kan en visualisering av lagerfyllnadsgrad påverka planeringsavdelningen i det operativa arbetet? Metod – Förstudien visar att en metod för att beräkna lagerfyllnadsgrad vid djupstapling saknas. Studien har med sin abduktiva ansats undersökt hur verksamheter arbetar med lagerfyllnadsgrad. Därefter har litteraturstudien analyserats och med stöd från insamlad empiri har författarna skapat en illustration av metoden. Resultat – Studien resulterade i en metod som beräknar lagerfyllnadsgrad och kan användas som ett analysunderlag vid optimering av lagerutrymmet. Metoden beräknar en plats- och en produktspecifik lagerfyllnadsgrad. Studien presenterar ett konkret exempel på hur metoden kan visualiseras och hur den är den är tänkt att användas. Implikationer – Metoden ämnar sig åt att inspirera till en ökad kontroll på hur mycket gods som finns på lagret. Den är specifikt inriktad på staplingsbart gods inom djuplagring för att hjälpa till vid en visualisering och beräkning av lagerfyllnadsgrad. Vid en implementering av metoden är det viktigt att förstå hur lagret fungerar och godsets parametrar för beräkning. Begränsningar – Metoden som tagits fram bygger på klämgods vid standardkvantiteter. Studien är en enfallsstudie vilket innebär att metoden troligen inte kan appliceras direkt på andra företag utan att granskas och justeras efter deras förutsättningar. Purpose – The purpose of the study is to identify a usable method to calculate stock fulfilment rate in a distribution warehouse and investigate how a visualization of the stock fulfilment rate affects the operative planning organisation. To fulfil the purpose of this study four research questions were formulated: 1. Which factors is needed to calculate the stock fulfilment rate for block stacking inventory in a distribution warehouse? What method could be used to calculate the stock fulfilment rate for block stacking inventory in a distribution warehouse? How could you summarize these factors to visualize the stock fulfillment rate? How can a visualization of the stock fulfillment rate affect the operative planning organisation? Method – The pre-study shows that the theory lacks a method for calculating the stock fulfilment rate with block stacking. The study has with its abductive approach investigated how businesses works with stock fulfilment rate. From this, the literature study has been analysed with support from the result and the authors has created an illustration of the method. Findings – The study resulted in a method which calculates stock fulfilment rate and can be used as an analytical information when optimizing the storage area. The method calculates a location- and product specific stock fulfilment rate. The study then presents an example on how the method could be visualized and used. Implications – The method aims at inspiring to an increased control of the warehouse storage capabilities. It is focused on block stacking and to help at a visualization and calculation of stock fulfilment rate. At an implementation stage is it important to understand that the storage and block stacking factors when doing the calculations. Limitations – The purposed method builds on block stacking and handling units. The study carried out is a case study which means that the result is not applicable directly without further examination of other businesses and their preconditions.

Syfte – Syftet med studien är att identifiera kritiska begränsningar i inlagringsprocessen i ett distributionslager för att därmed kunna effektivisera materialflödet. Studiens syfte uppnås genom att följande forskningsfrågor har formulerats: Vilka kritiska begränsningar kan förekomma i materialflödet i en inlagringsprocess i ett distributionslager? Hur kan de identifierade begränsningarna exkluderas i en inlagringsprocess? Metod – Studien hade en induktiv ansats och datainsamling skedde genom intervjuer, observationer, dokumentstudier och litteraturstudier. En fallstudie genomfördes på ett distributionslager och empiri och teori har jämförts för att kunna uppfylla studiens syfte. Resultat – Studiens resultat påvisar att de förekommande kritiska begränsningarna i ett distributionslager är brist på yta, materialhantering, automatiska system samt lagerlayout. Studiens slutsats är att begränsningarna är sammankopplade och påverkar varandra eftersom de ingår i samma process. För att exkludera begränsningarna bör distributionslager implementera diverse standarder i sin inlagringsprocess och arbeta med ständiga förbättringar. Implikationer – Studien bidrar inte med nya teorier men bidrar med praktisk nytta för distributionslager med liknande kriterier som studiens fallföretag. Begränsningar – Studien riktar enbart in sig på distributionslager och var en fallstudie av enfallsdesign. Genom att utföra flera liknande undersökningar på företag med liknande kriterier hade generaliserbarheten kunnat stärkas. Purpose – The purpose of the study is to identify critical constraints in the inbound process at a distribution warehouse. To accomplish the purpose two research questions were formulated: Which critical constraints can occur in the material flow in the inbound process at a distribution warehouse? How can the identified constraints be excluded in the inbound process? Method – The study was performed inductively, and the data collection techniques were interviews, observations, document studies and literature studies. A single case study was performed at a distribution warehouse and the empirical data and theories were compared to accomplish the purpose of the study. Findings – The result of the study demonstrates that the critical constraints in the inbound process at a distribution warehouse are space, material handling, automatic systems and warehouse layout. The conclusion of the study is that the constraints are connected and affect each other since they are all included in the same process. To exclude the constraints different types of standards should be implemented in the inbound process, and distribution warehouses should work with continuous improvements. Implications – The study does not contribute to new theories but can be practically beneficial for distribution warehouses similar to the studies case study. Limitations – The study only focuses on one distribution warehouse and is therefore a single case study. The generalizability could have been higher if the study had been conducted at multiple distribution warehouses.

With the increasing tempo of business, order picking efficiency becomes of increasing importance. The aim of this research is to find ways of increasing order picking efficiency by decreasing travel time of the picking cycle.Finding the optimal (shortest) order picking tour can be equated to the task of finding a solution to the Travelling Salesman Problem (TSP). This is notoriously difficult to solve in reasonable time when conventional computers are used. A number of heuristic algorithms have been developed for solving the TSP, some of these have been specially adapted for multiple command order picking. In this previous work the stacker crane's shuttle was assumed to travel with constant velocities in the horizontal and vertical directions. In this research it is shown that this assumption leads to creating suboptimal tours. The contribution of the error is analytically derived and its magnitude estimated by a simulation experiment. In previous work it has been shown that the shape of the zones in class based storage affects the travel time for single and dual command order picking. In this research, for the first time, the interaction between class based storage and multiple command order picking is investigated. Three types of zone configurations are modelled and then investigated using simulation in a factorial experiment. The results from the experiment indicate that the zone shape does affect the optimal solution.The new zone configurations are tested in a case study against existing configurations in a distribution warehouse of Volkswagen - Audi (VAG-UK). This showed that overall improvement in travel time of the new configurations was significant. Computer simulation was used to estimate the individual contribution from zoning and tour construction.