I dagens samhälle med en växande marknadsglobalisering och snabbt föränderlig marknadsmiljö är det viktigt att företag driver sina logistiska processer på ett effektivt sätt för att bemöta kundernas behov, hålla kostnaderna nere och bibehålla en konkurrenskraftig position. Lagrets utformning har stor påverkan på effektiviteten i hanteringen av artiklar och ett välskött lager kan minska leveranstiderna, öka kundnöjdheten och minska kostnaderna. I många företag används stora resurser på saker som inte tillför något värde. Syftet med denna studie var att undersöka och identifiera problem inom lagerhantering genom en egenutvecklad modell. Studien syftar också till att utvärdera och identifiera förbättringsförslag som kan effektivisera lagerhanteringen. Tre frågeställningar utvecklades för att tydliggöra för läsaren att studien fördjupat sig i lagerhanteringsaktiviteter som sker på lagret. Studien använde en kombination av kvalitativa och kvantitativa metoder för att uppnå en djupare förståelse av resultaten. Intervjuer, observationer och viss uträkning har använts för att undersöka lagerhanteringsaktiviteter. Undersökningen visade att det finns åtta aktiviteter på lagret som är viktiga för effektiviteten och att det uppstår slöserier i sex av de åtta aktiviteterna på det undersökta företaget. Modellen har hjälpt studien att komma fram till vilka lagerhanteringsaktiviteter som bidrar till icke-värdeskapande slöserier. Onödig bearbetning och väntetid uppstår i godsmottagningen, transport i ompaketering, transport och onödiga rörelser i inlagringen, lager, onödiga rörelse och överproduktion i lagring, transport och onödiga rörelser i orderplock samt väntetid vid utleverans. Resultatet i denna studie bringar klarhet i olika förbättringsförslag som kan minimera slöserier för att effektivisera lagerhanteringen. Studien visar att företaget kan minska transporttiden, hitta artiklar enklare, undvika onödig bearbetning samt minimera onödiga rörelser. / In today's society with growing market globalization and a rapidly changing market environment, it is important that companies run their logistics processes efficiently in order to meet customer needs, keep costs down and maintain a competitive position. The layout of the warehouse has a significant impact on the efficiency of handling items, and a well-managed warehouse can reduce delivery time, increase customer satisfaction, and reduce costs. In many companies, large resources are spent on things that add no value. The purpose of this study was to investigate and identify problems in inventory management through a self-developed model. The study also aims to evaluate and identify improvement proposals that can make inventory management more efficient. Three questions were developed to make it clear to the reader that the study focused on inventory management activities that take place in the warehouse. The study used a combination of qualitative and quantitative methods to achieve a deeper understanding of the findings. Interviews, observations and some calculation have been used to investigate inventory management activities.The investigation showed that there are eight activities in the warehouse that are important for efficiency and that waste occurs in six of them at the investigated company. The model has helped the study to determine which inventory management activities contribute to non-value-added waste. Unnecessary processing and waiting time occurs in goods reception, transport in repackaging, transport and unnecessary movements in storage, warehouse, unnecessary movement and overproduction in storage, transport and unnecessary movements in order picking and waiting time at delivery. The results of this study bring clarity to various improvement proposals that can minimize waste in order to make inventory management more efficient. The study shows that the company can reduce transport time, find products more easily, avoid unnecessary processing and minimize unnecessary movements. Keywords: lean, order picking, warehouse, warehouse design, warehouse management, warehouse location, methods

In recent years, Hallsta Paper Mill has experienced significant changes in the demand for paper. The ordershave become smaller and more customer-specific, while the graphical paper industry has steadily declined.As a result of these changes, the employees at Hallsta Paper Mill feel that the finished goods warehouse isno longer optimally designed, and they have identified that waste occurs in the warehouse. Therefore, thepurpose of the study was to provide suggestions on how the activities in the warehouse could become moretime-efficient and investigate how the finished goods warehouse could be designed to suit today’s demandbetter. To facilitate the answering of the purpose, three research questions were formulated: What areas ofimprovement exist in the finished goods warehouse regarding its activities and layout? What effects can beobtained by addressing the identified areas of improvement? and What solutions are recommended for thefinished goods warehouse at Hallsta Paper Mill? The study’s first research question was answered by conducting interviews, a spaghetti diagram, and ananalysis of produced paper rolls. The interviews were conducted with employees who either workoperationally or administratively in the warehouse to get a comprehensive picture of how the work isperformed and where waste occurs within the activities. The spaghetti diagram identified the movementpattern for the trucks in the warehouse and provided indications if unnecessary long transports occurred ornot. The analysis of produced paper rolls examined how well the storage compartments in the finishedgoods warehouse were dimensioned based on today’s demand. Based on the collected data, nine areas ofimprovement were identified, seven areas linked to the activities in the warehouse and two areas linked tothe layout of the warehouse. After the areas of improvement were identified, the study’s second research question was answered bydeveloping solutions within each area of improvement. To develop the solutions linked to the activities inthe warehouse, root cause analyses were performed, where each area was examined to find the root causeof the problem. For the solutions linked to the design, inspiration was instead taken from the warehouselayout and article placement literature. A total of 23 solutions were developed, 19 linked to the activitiesand four linked to the layout. For each solution, it was then analysed what effects an implementation of thesolution would provide, focusing on possible time savings. The effects were analysed with help from theliterature and the authors’ knowledge of logistics. After the effects had been analysed, each solution was assessed based on the effects identified in theprevious research question. The solutions were placed in effort-impact diagrams based on how much effortis required to implement the solution and how much impact is expected from the solution. When assessingthe impact, extra consideration was given to possible time savings, as it was the highest priority accordingto the directives from Hallsta Paper Mill. The assessment then resulted in a recommendation on how thesolutions should be approached. The less effort required and the more impact a solution would bring, thehigher priority was given to the solution. To summarise, two solutions were recommended to beimplemented immediately, nine solutions should be implemented in a second step, seven solutions shouldbe considered and investigated further, and two solutions should be rejected. The solutions aimed to makethe warehouse activities more time-efficient and suggest how the warehouse could be designed to suittoday’s demand better.

Bakgrund: Lagerverksamheten har en väsentlig betydelse och kan vara avgörande för organisationen övergripande prestanda och framgång, i synnerhet för SMF (små och medelstora företag). Driften av lagerverksamheten kan bli särskilt utmanande om organisationen befinner sig i en stark tillväxtfas och om den aktuella artikeln kännetecknas av behov. För att effektivt kunna bedriva sin lagerverksamhet bör organisationer utgå från en lagerdesign. Däremot redogör inte dagens forskning hur SMF som befinner sig i en stark tillväxtfas samt lagerhåller en artikel med behov bör utforma en sådan lagerdesign. Syfte: Denna studie syftar till att föreslå en lagerdesign som tar hänsyn till artikelns behov. Vidare ämnar studien att undersöka vilka konsekvenser en hög tillväxtfas har på ett SMF:s lagerverksamhet. Metod: Studien har studerat organisationen Nordic Green Design AB, ett svenskt SMF vars artikelsortiment utgörs av prydnadsväxter. Artikelns behov förutsätter krav på rätt temperatur, ljus och bevattning. Datainsamlingen har utgått från intervjuer med organisationens lagerpersonal och marknadschef samt via observationer av organisationens befintliga lagerdesign. Data har därefter analyserats utifrån den teoretiska referensramen. Slutsats: Studien betonar vikten av att fastställa behov och krav i samband med utformandet av en lagerdesign, i synnerhet när artikeln präglas av behov. Fastställandet av behov och krav fastställer ramarna för vilka lagerhanteringsmetoder som är tillämpbara i lagerdesignen. Genom att skifta fokus mot fastställandet av behov och krav kan en effektivare lagerverksamhet uppnås. Vidare indikerar studien på att en stark tillväxtfas bidrar till omfattande organisatoriska utmaningar. Studiens resultat antyder att en decentraliserad organisationsstruktur har bäst förutsättningar för att hantera dessa utmaningar. / Background: Warehousing activities are essential and can be crucial to the organizations overall performance and success, especially for SMEs (small and mediumsized enterprises). The warehouse operations can be particularly challenging if the organization is in a rapid growth phase and if the stored article is characterized by requirements. In order to effectively carry out the warehouse operations, organizations need to develop a warehouse design. However, today’s research does not acknowledge how SME’s with above-mentioned prerequisites should form such warehouse design. Purpose: This study aims at proposing a warehouse design that takes into account the requirements of the article. Furthermore, the study intends to examine the consequences of a rapid growth phase on an SME's warehouse. Method: This paper has studied the organization Nordic Green Design AB, a Swedish SME, whose articles consists of ornamental plants. These products require specific care such as temperature, light and irrigation regulation. The data collection was based on interviews with the organization's warehouse staff and marketing manager. Additionally, data was collected through observations of the organization's existing warehouse design. The data has then been analyzed based on the theoretical reference frame. Conclusion: The study emphasizes the importance of identifying needs and requirements when developing a warehouse design, especially when the article is characterized by requirements. The determination of needs and requirements determines the foundation of which storage management methods that are applicable in the warehouse design. By shifting focus to the determination of needs and requirements, more efficient storage can be achieved. Furthermore, the study indicates that a rapid growth phase contributes to extensive organizational challenges. The results of the study suggest that a decentralized organizational structure has the best prerequisites for managing these challenges.

Data Warehouses (DW) have to continuously adapt to evolving business requirements, which implies structure modification (schema changes) and data migration requirements in the system design. However, it is challenging for designers to control the performance and cost overhead of different schema change implementations. In this paper, we demonstrate SCIT, a tool for DW designers to test and implement different logical design alternatives in a two-fold manner. As a main functionality, SCIT translates common DW schema modifications into directly executable SQL scripts for relational database systems, facilitating design and testing automation. At the same time, SCIT assesses changes and recommends alternative design decisions to help designers improve logical designs and avoid common dimensional modeling pitfalls and mistakes. This paper serves as a walk-through of the system features, showcasing the interaction with the tool’s user interface in order to easily and effectively modify DW schemata and enable schema change analysis.

Decision support systems are interactive, computer-based information systems that provide data and analysis tools in order to better assist managers on different levels of organization in the process of decision making. Data warehouses (DWs) have been developed and deployed as an integral part of decision support systems. <p><p>A data warehouse is a database that allows to store high volume of historical data required for analytical purposes. This data is extracted from operational databases, transformed into a coherent whole, and loaded into a DW during the extraction-transformation-loading (ETL) process. <p><p>DW data can be dynamically manipulated using on-line analytical processing (OLAP) systems. DW and OLAP systems rely on a multidimensional model that includes measures, dimensions, and hierarchies. Measures are usually numeric additive values that are used for quantitative evaluation of different aspects about organization. Dimensions provide different analysis perspectives while hierarchies allow to analyze measures on different levels of detail. <p><p>Nevertheless, currently, designers as well as users find difficult to specify multidimensional elements required for analysis. One reason for that is the lack of conceptual models for DW and OLAP system design, which would allow to express data requirements on an abstract level without considering implementation details. Another problem is that many kinds of complex hierarchies arising in real-world situations are not addressed by current DW and OLAP systems.<p><p>In order to help designers to build conceptual models for decision-support systems and to help users in better understanding the data to be analyzed, in this thesis we propose the MultiDimER model - a conceptual model used for representing multidimensional data for DW and OLAP applications. Our model is mainly based on the existing ER constructs, for example, entity types, attributes, relationship types with their usual semantics, allowing to represent the common concepts of dimensions, hierarchies, and measures. It also includes a conceptual classification of different kinds of hierarchies existing in real-world situations and proposes graphical notations for them.<p><p>On the other hand, currently users of DW and OLAP systems demand also the inclusion of spatial data, visualization of which allows to reveal patterns that are difficult to discover otherwise. The advantage of using spatial data in the analysis process is widely recognized since it allows to reveal patterns that are difficult to discover otherwise. <p><p>However, although DWs typically include a spatial or a location dimension, this dimension is usually represented in an alphanumeric format. Furthermore, there is still a lack of a systematic study that analyze the inclusion as well as the management of hierarchies and measures that are represented using spatial data. <p><p>With the aim of satisfying the growing requirements of decision-making users, we extend the MultiDimER model by allowing to include spatial data in the different elements composing the multidimensional model. The novelty of our contribution lays in the fact that a multidimensional model is seldom used for representing spatial data. To succeed with our proposal, we applied the research achievements in the field of spatial databases to the specific features of a multidimensional model. The spatial extension of a multidimensional model raises several issues, to which we refer in this thesis, such as the influence of different topological relationships between spatial objects forming a hierarchy on the procedures required for measure aggregations, aggregations of spatial measures, the inclusion of spatial measures without the presence of spatial dimensions, among others. <p><p>Moreover, one of the important characteristics of multidimensional models is the presence of a time dimension for keeping track of changes in measures. However, this dimension cannot be used to model changes in other dimensions. <p>Therefore, usual multidimensional models are not symmetric in the way of representing changes for measures and dimensions. Further, there is still a lack of analysis indicating which concepts already developed for providing temporal support in conventional databases can be applied and be useful for different elements composing a multidimensional model. <p><p>In order to handle in a similar manner temporal changes to all elements of a multidimensional model, we introduce a temporal extension for the MultiDimER model. This extension is based on the research in the area of temporal databases, which have been successfully used for modeling time-varying information for several decades. We propose the inclusion of different temporal types, such as valid and transaction time, which are obtained from source systems, in addition to the DW loading time generated in DWs. We use this temporal support for a conceptual representation of time-varying dimensions, hierarchies, and measures. We also refer to specific constraints that should be imposed on time-varying hierarchies and to the problem of handling multiple time granularities between source systems and DWs. <p><p>Furthermore, the design of DWs is not an easy task. It requires to consider all phases from the requirements specification to the final implementation including the ETL process. It should also take into account that the inclusion of different data items in a DW depends on both, users' needs and data availability in source systems. However, currently, designers must rely on their experience due to the lack of a methodological framework that considers above-mentioned aspects. <p><p>In order to assist developers during the DW design process, we propose a methodology for the design of conventional, spatial, and temporal DWs. We refer to different phases, such as requirements specification, conceptual, logical, and physical modeling. We include three different methods for requirements specification depending on whether users, operational data sources, or both are the driving force in the process of requirement gathering. We show how each method leads to the creation of a conceptual multidimensional model. We also present logical and physical design phases that refer to DW structures and the ETL process.<p><p>To ensure the correctness of the proposed conceptual models, i.e. with conventional data, with the spatial data, and with time-varying data, we formally define them providing their syntax and semantics. With the aim of assessing the usability of our conceptual model including representation of different kinds of hierarchies as well as spatial and temporal support, we present real-world examples. Pursuing the goal that the proposed conceptual solutions can be implemented, we include their logical representations using relational and object-relational databases.<p> / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished