This dissertation comprises three essays in which we develop optimization, econometric, and simulation models to help traditional retailers improve in-store operations. Our modeling efforts aim to tackle inventory record inaccuracy (IRI) and suboptimal staffing levels, both of which are pervasive problems in retailing and cause non-trivial profit loss. In the first essay, we devise two optimization models that represent current practices in industry to minimize costs induced by IRI: daily-fraction and all-or-none inspection. We further perform a case study to identify deficiencies of store operating practices given different risk preferences. Our findings provide practical guidelines for managers to design cost-efficient inspection policy. In the second essay, we develop a dynamic simulation model to analyze multiple antecedents of IRI. Based on simulation results, we derive two hypotheses on the association between IRI and labor. The panel data analysis shows that both the level and the mix of store labor have strong impacts on IRI. Our analysis derives qualitative insights for retail managers to prevent the occurrence of IRI. Finally, in the third essay, we perform an empirical study to improve staffing decisions in retailing. We first develop a response function to quantify the impact of labor and traffic on sales. Grounded on the function we propose a traffic-based staffing heuristic, which performs closely to the optimal and outperforms existing staffing levels in counterfactual experiments. A major contribution of our study is to quantify the benefits of delivering labor plans based on traffic information. Also, the staffing approach is easy to use and saves the need for traffic forecasting.

Companies can satisfy their customers and stakeholders, become competitive and develop their effectiveness through effective logistic. The customers do not only request the right product andquality but also delivery precision. For the industries to deliver in time it is essential to have raw material and components in time to produce the products that the customer request. A correct inventoryrecord makes it easier to see when ordering is required and makes it possible to implement automatic order system. Many companies though, are struggling with their record accuracy. A company thatcould benefit from improving their record accuracy is SweProd Graphics AB. This student thesis aims therefore to find possible solutions to improve the inventory record accuracy. The issues that are treated in this thesis are the following: How well does the actual stock balance match the reported inventory balance? How to improve the inventory record accuracy? Which are the possibilities with the new ERP that the company are planning to implement and how can they use it? The method to answer these questions are interviews, researches in Visma, inventories, benchmarking, process mapping and literature studies. The theories deal with the importance of correct stockbalance, how stocktaking can be simplified and followed up, different methods for inventory accounting and different material planning system. The result showed that there is a need of improving the inventory record accuracy. Today the inventoried quantity is both more and less than the reported inventory balance. Nine potential reasons areidentified, these are among delivery, outbound and stocktaking. The suggestions to improve the inventory record accuracy are to record the transactions at the start of an order, simplifying the stocktaking, keep statistics over stocktaking and establish reorder points and two bin system. / Genom effektivare logistik kan företag tillfredsställa kunder och övriga intressenters behov, bli konkurrenskraftiga och öka sin effektivitet. Möjligheten att tillfredsställa kundernas behov är beroende av tillgång till material. Kunden efterfrågar inte bara rätt produkt och kvalitet utan också leveransprecision. För att de producerande företagen ska kunna leverera i tid krävs det att de har tillgång till material och komponenter för att kunna producera de produkter som kunden efterfrågar. Ett korrekt redovisat lagersaldo gör det enklare att se när material behöver beställas in och gör det möjligt att införa automatiska beställningssystem. Många företag har dock inte korrekt redovisade lagersaldon idag. Ett av de företag som skulle ha nytta av att förbättra sin lagerredovisning är SweProd Graphics AB. Examensarbetet som utförs på SweProd Graphics AB syftar därför till att finna möjliga tillvägagångssätt för att förbättra lagersaldosäkerheten. Frågeställningarna som behandlas i arbetet är:  <ul type="disc">Hur väl stämmer det verkliga lagersaldot med det redovisade lagersaldot i Visma?   Hur kan lagersaldosäkerheten förbättras?  Hur kan företaget använda sig av det systemstöd som ska införas? För att besvara frågeställningarna har intervjuer, undersökningar i Visma, inventeringar, benchmarking, processkartläggning och litteraturstudier använts som metod. Teorierna behandlar vikten av korrekt lagersaldo, hur inventeringar kan förenklas och följas upp, olika metoder för lagerredovisning och olika materialplaneringssystem.  Resultatet visade på att det finns ett behov av att förbättra redovisningen av lagersaldot. Som det ser ut i dagsläget är det inventerade antalet både mer och mindre än vad systemet redovisar. Nio potentiella orsaker till varför lagersaldot inte stämmer har identifierats, dessa återfinns både inom inleverans, utleverans och inventering. För att förbättra lagersaldosäkerheten ska förslagsvis materialuttag registreras vid start av produktionsorder, inventering förenklas, statistik föras över inventering och beställningspunkt och tvålådesystem införas.

Syftet med den här rapporten har varit att undersöka möjligheterna att automatisera själva inventeringsarbetet med hjälp av drönare. Rapporten ska lyfta fram vilka kravspecifikationer en drönare skulle behöva uppfylla för att detta ens skulle kunna vara möjligt överhuvudtaget samt undersöka på vilket sätt detta kan medföra effektivisering av inventeringsprocessen och minimera risk för olyckor. Rapportens uppbyggnad består utav att olika kravspecifikationer presenteras enskilt från drönaren i den teoretiska referensramen som sedans knyts samman i analysen där författarna presenterar de utvalda kravspecifikationerna som kan anses vara mest lämpliga, baserat på vald teori, empiri och avgränsningsområdet. För att kunna besvara vårt syfte så fanns det en del frågeställningar som behövde svar, där fyra företag intervjuades. Med dessa frågor kunde det skapas en uppfattning kring hur inventeringsprocessen såg ut hos olika företag idag och vilka svårigheter man upplevde i samband med processerna. Det noterades snabbt att alla involverade företagen upplevde gemensamma problem vid sina inventeringsprocesser och ansåg att en automatiserad lösning var något att vänta sig inom en snar framtid. De ansåg att inventeringsprocessen var tidskrävande och en icke värdeskapande aktivitet där man kunde lägga resurserna på annat. Trots att inventeringen ansågs vara icke värdeskapande, så är det fortfarande en aktivitet som måste utföras delvis för lagkrav men även för att kunna behålla hög service nivå och leveransförmåga. Vidare lyfts det fram i rapporten hur en möjlig körplan med drönare kan se ut, hur denna möjligtvis kan effektivisera arbetet och den reducering av risk för olyckor som sker på gods och personal i samband med inventeringen. Författarna anser att tekniken för att kunna uppnå detta finns tillgänglig, utan det handlar mer om hur man använder tekniken och utformar miljön som drönaren ska verka i för att det ska bli så optimalt som möjligt. Vidare drogs slutsatsen att det kommer att ta tid tills detta kan helautomatiserats och kommer till en början behöva kompletteras med stöd från den mänskliga faktorn. / The purpose of this report has been to investigate the possibilities of automating the inventory process with the help of drones as well as investigating how this can make the inventory process more efficient. Furthermore, the report will highlight the specifications that a drone would have to meet in order for this to be possible at all, as well as investigate how this could lead to a more effective inventory process and minimizing the risk of accidents that occurs during the inventory process. The structure of the report consists of different specifications that are presented where the authors selected requirement specifications which are considered most suitable based on the chosen theory and empirical studies. In order to answer the purpose of this assignment, there were a few questions that needed some research in order to find relevant answers where four companies were interviewed. With these questions, we would be able to get an idea of ​​how the inventory process looked at different companies and what difficulties they experienced in the processes. All the interviewed companies often experienced common problems in their inventory processes and told the authors that an automated solution was something to be expected in the near future. Furthermore, they considered that the inventory process was time-consuming and a non-value-creating activity where one could put the resources elsewhere if there was a drone able to perform the expected work because of, despite the fact that the inventory was considered to be non-value-creating, it is still an activity that must be performed since it is a legal requirement, but also to maintain a high level of service and good delivery ability. Furthermore, a plan for how the drone should work is presented and how it possibly would make the inventory process more effective and minimize the risk of accidents that can occur on goods and staff. The authors believe that the technology for achieving this is available, but it is more about using the technology and designing the warehouse to make this as optimal as possible. Furthermore, the authors believe that it will take time until it can be fully automated and will initially, have to be supplemented with support from the human factor.

Sammanfattning Kurs: Examensarbete i Logistik för Civilekonomprogrammet, 30 hp, 4FE19E.  Författare: Jakob Bergman och Jim Andersson. Examinator: Peter Berling Handledare: Peter Berling  Medbedömare: Hana Hulthén Titel: Saldoavvikelser i producerande företag, en fallstudie på Getinge Disinfection AB. Bakgrund: En välfungerande lagerhållning är en väsentlig grundsten för ett företags framgångar. I takt med att lagerhållningen blivit mer automatiserad och effektiviserad ställs högre krav på att informationen om lagersaldon stämmer överens med verkligheten. Saldoavvikelser är ett utbrett problem som kan påverka många olika delar av en verksamhet, såsom felaktiga underlag för inköp, den dagliga driften och företagets servicegrad. Fallföretaget Getinge Disinfection AB upplever främst att saldoavvikelser på företaget får effekt på den dagliga driften, något som denna studie ämnar undersöka. Syfte: Studien syftar till att identifiera konsekvenser och orsaker till saldoavvikelser på Getinge Disinfection AB samt ge förbättringsförslag som kan reducera saldoavvikelser på företaget. Metod: Denna studie har en kvalitativ forskningsstrategi. Vidare är studiens forskningsdesign en fallstudie då den endast undersöker ett fall ingående och detaljerat. Resultat: Studien fann att saldoavvikelser kan uppstå i alla steg i den studerade processen, med varierande primära orsaker i de olika stegen i processen. Bland de konsekvenser som funnits är de främsta icke-värdeskapande aktiviteter, opålitliga underlag för inköpsbeslut, OOS och ökade ledtider. Majoriteten av orsakerna grundar sig i den mänskliga faktorn, det vill säga att anställda inte följer rutiner eller gör misstag i processen. Dessa misstag kan ske i olika aktiviteter i processen och det finns olika primärorsaker beroende på var i processen misstaget sker. Vidare har författarna tagit fram förbättringsförslag för att effektivisera Getinge Disinfection ABs produktionsprocess. De mest lämpliga förbättringsförslagen är att skapa förståelse om saldoavvikelser bland de anställda, införa Cycle counting, digitalisera olika aktiviteter och utvärdera det nuvarande artikelsortimentet. Nyckelord: Saldosäkerhet, Saldoavvikelser, Producerande företag, Medicinteknik, Life Science, Assemble to Order, ATO, Cycle Counting, RFID, Streckkoder. / Abstract  Course: Degree project in Logistics, the Business Administration and Economics Programme, 30 credits, 4FE19E.    Authors: Jakob Bergman and Jim Andersson. Examiner: Peter Berling.  Tutor: Peter Berling. Co-judger: Hana Hulthén Title: Inventory record inaccuracies in manufacturing companies, a case study on Getinge Disinfection AB. Background: Effective inventory management is of considerable importance for most successful businesses. Without it, companies would be hard-pressed to meet the demands of consumers that place a high value on fast deliveries and product availability. As a result, businesses have turned to increased automation of their inventory management. This automation relies heavily on information such as inventory records being accurate and up to date. Inventory record inaccuracies result in purchases or decisions being made on incorrect assumptions of the companies’ actual inventory status, which has a negative effect on many aspects of the business. However, most studies on this subject focus on inventory record inaccuracies in a retailing context, whereas this study focuses on a large manufacturing company (Getinge Disinfection AB) using an Assemble to Order model. Purpose: The purpose of this study is to identify the different causes and consequences of inventory record inaccuracies (IRI) at Getinge Disinfection AB. Furthermore, the study aims to offer proposals on how to improve inventory record accuracy at Getinge Disinfection AB.    Methodology: This paper adopts a qualitative research strategy with a case-study approach.  Findings: The study concluded that inventory record inaccuracies can arise in all areas of the studied process, with different primary reasons for different stages of the process. Most of the causes of IRI can be attributed to the human factor, such as incorrect identification of the items, unregistered movements of goods, and transaction errors. The consequences of (IRI) were mainly the resulting non-value adding activities, purchasing decisions being made based on unreliable inventory data, stockouts and longer lead times. The study also gives suggestions on how Getinge could reduce these inventory record inaccuracies. Improvement measures such as Cycle counting, bar coding of the items and locations and increased staff training are discussed. Keywords: Inventory Record Accuracy, Inventory Record Inaccuracy, Manufacturing, Health Care, Life Science, Assemble to Order, ATO, Cycle Counting, RFID, Bar coding.

<p>In today‟s manufacturing environment, different parts manufactured in-house and bought from suppliers are often assembled together into a finished product. Competition has made it very important for companies to deliver a customized product on a promised date. However, when inventory items are missing at the time of production, lead times for products become uncertain and this makes it difficult to fulfill a customer order on the promised date. It is thus important to explore the causes of missing items at the time of production in order to solve such a problem. This Master of Science thesis carried out through a case study at Fläkt Woods in collaboration with Jönköping University is about the problem of not finding specific inventory items in the locations specified by the computer system. It is delimited to inventory items which are physically within the company premises or which according to the computer system are within the premises of the company. The questions at issue have been what the causes of the problem of missing items within the company are and how to effectively reduce the problem. The thesis has been carried out over an entire academic semester as a full-time work in the company. The sources of the problem have been found to be the result of the work procedure, the underlying software used during work (the in-house developed ERP system), stealing from orders, ineffective barcode scans, re-sequencing at the component manufacturing department (called pre-manufacturing in the company) due to the need to fulfill multiple objectives, set-up times at the component manufacturing department and human errors among others. The suggestions given include: modification of the work procedure and the underlying software used at work, increasing effective scanning and using some checks at critical points in the material flow. Areas for further research are given to further reduce the impact of the problem on the production system.</p>

In today‟s manufacturing environment, different parts manufactured in-house and bought from suppliers are often assembled together into a finished product. Competition has made it very important for companies to deliver a customized product on a promised date. However, when inventory items are missing at the time of production, lead times for products become uncertain and this makes it difficult to fulfill a customer order on the promised date. It is thus important to explore the causes of missing items at the time of production in order to solve such a problem. This Master of Science thesis carried out through a case study at Fläkt Woods in collaboration with Jönköping University is about the problem of not finding specific inventory items in the locations specified by the computer system. It is delimited to inventory items which are physically within the company premises or which according to the computer system are within the premises of the company. The questions at issue have been what the causes of the problem of missing items within the company are and how to effectively reduce the problem. The thesis has been carried out over an entire academic semester as a full-time work in the company. The sources of the problem have been found to be the result of the work procedure, the underlying software used during work (the in-house developed ERP system), stealing from orders, ineffective barcode scans, re-sequencing at the component manufacturing department (called pre-manufacturing in the company) due to the need to fulfill multiple objectives, set-up times at the component manufacturing department and human errors among others. The suggestions given include: modification of the work procedure and the underlying software used at work, increasing effective scanning and using some checks at critical points in the material flow. Areas for further research are given to further reduce the impact of the problem on the production system.

La presente investigación realizada tiene como objetivo principal mejorar el nivel de servicio para la entrega de los productos terminados en una empresa manufacturera de cables eléctricos. Por ende, se aplicó la metodología de Planificación de Requerimiento de Materiales (MRP), cuya herramienta y método permitirá desplegar una propuesta de solución sólida, científica y aplicada a la problemática actual. En primer lugar, se realizó la revisión bibliográfica, citando fuentes y artículos científicos que sustenten y avalen la investigación. Seguidamente, se realizó el análisis de la problemática actual y determinación de causas, para ello se aplicaron métodos y herramientas de ingeniería industrial para la obtención de las causas raíz del problema, las cuales estaban ligadas a los métodos de la empresa. En consecuencia, se formula la hipótesis que la aplicación del MRP, a través del registro de inventario, lista de materiales y el plan maestro de producción (PMP), permitirá mitigar el impacto operativo y económico del problema principal, el cual son los retrasos en la entrega de producto terminado a los clientes. Dicha hipótesis es materia de estudio del siguiente capítulo, donde, en primer lugar, se sustenta que el MRP es la propuesta de mejora que mejor se ajusta a la descripción y la naturaleza de la presente investigación; para luego desplegar propiamente la metodología en sí. Dicho despliegue se realizó a través de la aplicación de la herramienta del MRP antes mencionadas, estructurada bajo un diseño de propuesta basado en planear, ejecutar, verificar y actuar. Finalmente, para la comprobación y verificación de la solución al problema, se realizó una simulación de la propuesta a través de un software, donde se comprobó que efectivamente, luego de la aplicación de la propuesta, se lograría reducir los retrasos en la entrega del producto terminado a los clientes. Además, se realizó una evaluación económica de la propuesta para comprobar la viabilidad del proyecto, respaldando así la presente investigación. / The main objective of the present investigation carried out is to improve the level of service for the delivery of finished products in an electrical cable manufacturing company. Therefore, the Materials Requirement Planning (MRP) methodology was applied, whose tool and method will allow the deployment of a solid, scientific solution proposal applied to the current problem. In the first place, the bibliographic review was carried out, citing sources and scientific articles that support and endorse the research. Next, the analysis of the current problem and determination of causes was carried out, for this, industrial engineering methods and tools were applied to obtain the root causes of the problem, which were linked to the company's methods. Consequently, the hypothesis is formulated that the application of the MRP, through the inventory record, the list of materials and the master production plan (PMP), will mitigate the operational and economic impact of the main problem, which are the delays in delivery of finished product to customers. This hypothesis is the subject of study in the next chapter, where, firstly, it is argued that the MRP is the improvement proposal that best fits the description and nature of the present investigation; and then properly deploy the methodology itself. Said deployment was carried out through the application of the aforementioned MRP tool, structured under a proposal design based on planning, executing, verifying and acting. Finally, for the verification and verification of the solution to the problem, a simulation of the proposal was carried out through software, where it was verified that effectively, after the application of the proposal, it would be possible to reduce the delays in the delivery of the product finished to customers. In addition, an economic evaluation of the proposal was carried out to verify the viability of the project, thus supporting the present investigation. / Trabajo de Suficiencia Profesional