As the effort of today’s industries to continuously move towards lean production, pull production system has been developed as one possible solution of lean. It is popularly known in the industry world, and is indeed a proven technique to achieve substantial savings on inventory, production cost incurred by manufactures all over the world. However, a careful understanding of pull production systems is required to access its suitability to a particular production setup. It is necessary to develop a proper way to implement pull production systems.             This study is based on a real life scenario in a leading driveline manufacturing company. The production system is studied in detail as regard to its production characteristic. A theoretical review is first made as research foundation. A careful analysis study within the company is conducted with all the existing constrains to figure out improvement opportunities. Eventually, from the applicability point of view, proposals of future pull production system implementation have been developed. The objective of the proposals is to minimize the identified weaknesses of the current system, including long lead time, low flexibility and unconnected flow.

Many important software systems, including communication protocols and concurrent and distributed algorithms generate infinite state-spaces. Model-checking which is the most prominent algorithmic technique for the verification of concurrent systems is restricted to the analysis of finite-state models. Algorithmic analysis of infinite-state models is complicated--most interesting properties are undecidable for sufficiently expressive classes of infinite-state models. In this thesis, we focus on the development of algorithmic analysis techniques for two important classes of infinite-state models: FIFO Systems and Parameterized Systems. FIFO systems consisting of a set of finite-state machines that communicate via unbounded, perfect, FIFO channels arise naturally in the analysis of distributed protocols. We study the problem of computing the set of reachable states of a FIFO system composed of piecewise components. This problem is closely related to calculating the set of all possible channel contents, i.e. the limit language. We present new algorithms for calculating the limit language of a system with a single communication channel and important subclasses of multi-channel systems. We also discuss the complexity of these algorithms. Furthermore, we present a procedure that translates a piecewise FIFO system to an abridged structure, representing an expressive abstraction of the system. We show that we can analyze the infinite computations of the more concrete model by analyzing the computations of the finite, abridged model. Parameterized systems are a common model of computation for concurrent systems consisting of an arbitrary number of homogenous processes. We study the reachability problem in parameterized systems of infinite-state processes. We describe a framework that combines Abstract Interpretation with a backward-reachability algorithm. Our key idea is to create an abstract domain in which each element (a) represents the lower bound on the number of processes at a control location and (b) employs a numeric abstract domain to capture arithmetic relations among variables of the processes. We also provide an extrapolation operator for the domain to guarantee sound termination of the backward-reachability algorithm.

In today’smanufacturing climate there is an increased focus on the use of the principles that form the foundation for the Lean manufacturing philosophy to create efficient and effective companies. Within Lean there is a great focus on identifying and eliminating waste. One of the seven wastes that Lean thinking strives to eliminate is the keeping of unnecessary inventory. The purpose ofthis study is to discover areas of improvement in a production flow and to give suggestions on these through finding and eliminating waste in the production environment. The production flow has been mapped using value stream mapping and has been analyzed accordingly. The specific production flow that has been mapped is located to a plant in the southern parts of Sweden and is operating within the plastic industry. At this plant, a specific product family has been mapped from raw material to shipment. In parallel with the empirical work literature studies have been conducted. The literature studies have sought to create a theoretical support for the result of the study. The current state at the factory has been mapped to create an understanding for the authors and the reader but also to give the study credibility with the company.  At the company observations and interviews have been conducted, mainly within two areas; the extrusion and the conversion into sheets. In addition to this thorough observations and calculations of inventory levels have been made, mainly in the semi-finished goods inventory. As the current state has been mapped thoroughly an analysis of the value stream has been conducted. Two areas have been focused upon in the analysis; the semi-finished goods inventory and the sheeting process. The observations and the analysis have shown disorganization in the inventory which causes materialto be forgotten and obsolete. In the sheeting process the analysis has shown that the lack of work instructions leads to variations in the cycle time and to variations in the mode of work. The inconsistency in the way work is conducted makes it difficult to obtain a common standard on quality. The analysis has resulted in an action plan which will lead to improvements in the production flow. In connection to this a future state map has been developed illustrating the desired state. The points of action are focused on the semi-finished goods inventory and the sheeting process. The major changes are the implementation of a FIFO-lane to increase the structure in the inventory and the development of work instructions for the sheeting process. The method used has been discussed and also the results obtained in the study and the compliance of the results with the purpose and thesis questions have been discussed. The study has also lead to suggestions for further studies that the company should investigate.

Many important software systems, including communication protocols and concurrent and distributed algorithms generate infinite state-spaces. Model-checking which is the most prominent algorithmic technique for the verification of concurrent systems is restricted to the analysis of finite-state models. Algorithmic analysis of infinite-state models is complicated--most interesting properties are undecidable for sufficiently expressive classes of infinite-state models. In this thesis, we focus on the development of algorithmic analysis techniques for two important classes of infinite-state models: FIFO Systems and Parameterized Systems. FIFO systems consisting of a set of finite-state machines that communicate via unbounded, perfect, FIFO channels arise naturally in the analysis of distributed protocols. We study the problem of computing the set of reachable states of a FIFO system composed of piecewise components. This problem is closely related to calculating the set of all possible channel contents, i.e. the limit language. We present new algorithms for calculating the limit language of a system with a single communication channel and important subclasses of multi-channel systems. We also discuss the complexity of these algorithms. Furthermore, we present a procedure that translates a piecewise FIFO system to an abridged structure, representing an expressive abstraction of the system. We show that we can analyze the infinite computations of the more concrete model by analyzing the computations of the finite, abridged model. Parameterized systems are a common model of computation for concurrent systems consisting of an arbitrary number of homogenous processes. We study the reachability problem in parameterized systems of infinite-state processes. We describe a framework that combines Abstract Interpretation with a backward-reachability algorithm. Our key idea is to create an abstract domain in which each element (a) represents the lower bound on the number of processes at a control location and (b) employs a numeric abstract domain to capture arithmetic relations among variables of the processes. We also provide an extrapolation operator for the domain to guarantee sound termination of the backward-reachability algorithm.

<p>The United States Securities and Exchange Commission (SEC) issued a Roadmap in 2008 regarding a change in the American accounting standards system. The Roadmap proposes a potential adoption from the United States Generally Accepted Accounting Principles (US GAAP) to the International Financial Reporting Standards (IFRS). The objective with the adoption is to enhance a one-set of accounting standards used in the world in order to increase comparability between public limited companies in different jurisdictions. With the adoption, the valuation of inventories for American companies will change, since the Last-In, First-Out (LIFO) method is allowed under US GAAP, but not under IFRS. A study from 2008 shows that approximately 36 per cent of American public limited companies is using LIFO. They would therefore be forced to use another inventory valuation method, such as First-In, First-Out (FIFO). The LIFO method is normally used by companies exposed to inflation and increases the cost of goods sold (COGS) and consequently lowers the net income and income tax provision. With the potential adoption, these companies would face large increases of income tax provisions, which would affect them severely.</p><p>This thesis is a review study with the objective to connect recent research with the SEC Roadmap in order to answer the following research questions: How will US companies that are using LIFO be affected by the inventory valuation change to FIFO, from an economic and accounting-based approach? What are the positive and negative aspects with a removal of LIFO regarding the IFRS adoption?</p><p>There is a clear benefit for the US companies using LIFO regarding the smaller income tax provisions. Opponents consider that LIFO will disappear with the US adoption to IFRS. At the same time, recent research considers or doubts that the LIFO method will not face its death with the adoption from US GAAP to IFRS. As a conclusion, the negative effect of removing LIFO as a consequence of this adoption, is the implementation time period, which is too optimistic. Even though, the credibility with a shift from LIFO to FIFO will grow stronger and create a more comparable business world.</p>

Multi-ported memories are challenging to implement on FPGAs since the provided block RAMs typically have only two ports. In this dissertation we present a thorough exploration of the design space of FPGA multi-ported memories by evaluating conventional solutions to this problem, and introduce a new design that efficiently combines block RAMs into multi-ported memories with arbitrary numbers of read and write ports and true random access to any memory location, while achieving significantly higher operating frequencies than conventional approaches. For example we build a 256-location, 32-bit, 12-ported (4-write, 8-read) memory that operates at 281 MHz on Altera Stratix III FPGAs while consuming an area equivalent to 3679 ALMs: a 43% speed improvement and 84% area reduction over a pure ALM implemen- tation, and a 61% speed improvement over a pure "multipumped" implementation, although the pure multipumped implementation is 7.2-fold smaller.

Multi-ported memories are challenging to implement on FPGAs since the provided block RAMs typically have only two ports. In this dissertation we present a thorough exploration of the design space of FPGA multi-ported memories by evaluating conventional solutions to this problem, and introduce a new design that efficiently combines block RAMs into multi-ported memories with arbitrary numbers of read and write ports and true random access to any memory location, while achieving significantly higher operating frequencies than conventional approaches. For example we build a 256-location, 32-bit, 12-ported (4-write, 8-read) memory that operates at 281 MHz on Altera Stratix III FPGAs while consuming an area equivalent to 3679 ALMs: a 43% speed improvement and 84% area reduction over a pure ALM implemen- tation, and a 61% speed improvement over a pure "multipumped" implementation, although the pure multipumped implementation is 7.2-fold smaller.

Purpose – The purpose of the study is to investigate how warehouse layout and materials handling affects the performance targets; cost and quality in an enterprise where more than one method is operationally active. In order to accomplish the purpose of the study two research questions were formulated.   1. How will the choices that an enterprise makes regarding different methods within warehouse layout and materials handling affect cost and quality?   2. How are methods within warehouse layout and materials handling interacting when being active simultaneously in an enterprise?   Method – In order to accomplish the purpose and answer the chosen research questions a case study has been conducted at a distribution centre. Interview and observation are the employed data collection techniques when collecting relevant data. To establish the theoretical framework a literature review has been carried out. Collected data and theoretical framework have subsequently been used to answer the research questions.   Findings – The choices that an enterprise makes when using different storage methods has been shown to influence cost and quality in various ways, with free stacking having the most negative impact. Coexistence between the materials handling methods; FIFO and cross-docking, might result in an enterprise ignoring visions and policies. In other words, the relationship between operative active methods needs to be taken in to consideration in order to fulfil performance targets.   Implications – The theoretical implication with the study has been to enlighten a new aspect of already existing theory, where the relationship between FIFO and cross-docking has been the focus of analysis. This might assist enterprises in gaining knowledge when using operationally active methods simultaneously. A practical implication of the study is that enterprises must understand in what ways the coexistence of storage methods might disrupt flow of products in a distribution centre. In this way, this study contributes to raising awareness among enterprises in terms of finding novel approaches to working with storage with the main purpose of improving their logistics performance.   Limitations – The ability to generalize the study can be questioned due to the fact that it consists of only one business case. Moreover, surrounding factors, which could have brought valuable data to the investigation, have been excluded due to the limited scope of the study.

The following thesis is based on a study on warehousing for an inventory of finished goods at Volvo Construction Equipment in Eskilstuna.   The inventory stores components consisting axles and transmissions. The project portrays a current situation analysis based on collected primary data, in form of interviews and observations. The current situation analysis includes a detailed process mapping, different warehouse layouts along with calculations. These aspects have been used in the development of improvement propositions.   The company is currently required to deliver components according to FIFO (First In, First Out), that is therefore fundamental when designing the following thesis. The project has however not been based on implementing FIFO, but only improving the existing management of FIFO. The current way of working with FIFO at the company is not ideal, consequently contributed to lack of storage space. This has eventually led to some components being stored outside the warehouse. It means that the components will not be weather-protected, which is one of the aspects that the company wishes to improve.   The Authors have presented various improvement propositions consisting investing in a: pallet, mobile- and a push back racking system and an improved inventory layout. These suggestions have been compared based on various factors that could be prioritized by the company. Examples on these key factors are: cost, volume utilization and enforcement of FIFO. The cost analysis for the racking systems are based on assistance from suppliers that has led to an enhanced cost comparison. The presented propositions have been delimited to ultimately being able to decide the final suggestion. For further studies, the company is recommended to invest in a pallet racking system, which is not only a beneficial economical solution, but also solves space shortage while all the components are stored with weather- protection. This will ultimately lead to improvement on managing FIFO in the finished goods inventory that the company strives after. / Detta examensarbete är grundat på undersökningar inom lagerhanteringen i färdigvarulagret (FVL) på Volvo Construction Equipment i Eskilstuna.   Färdigvarulagret lagerhåller i dagsläget komponenter bestående av axlar och transmissioner. Detta arbete redogör en nulägesbeskrivning som har tagits fram med hjälp av insamlad primärdata, i form av intervjuer och observationer. Nulägesbeskrivningen innefattar bland annat en detaljerad processkartläggning, olika lagerlayouts samt beräkningar som har varit fördelaktigt vid framtagandet av förbättringsförslagen. Den insamlade primärdata har jämförts med den teoretiska referensramen, som har varit till stöd vid utformningen av förslagen.   Företaget har i dagsläget krav på att leverera komponenter enligt FIFO (First In, First Out), som därmed är grunden till examensarbetet. Detta arbete har inte utgått från att implementera FIFO, utan att endast förbättra den befintliga hanteringen. Dagens arbetssätt av FIFO är inte optimal, i och med att det har bidragit till platsbrist i lagret. Detta har lett till att vissa komponenter lagerhålls i ett utelager som är placerat utanför FVL. Komponenterna som lagras i utelagret blir inte väderskyddade, vilket är en av de faktorer som företaget vill lösa.   Författarna har tagit fram olika förbättringsförslag bestående av införandet av ett: mobilt-, pall och rullfackställage, eller en ny lagerlayout. Dessa förslag har jämförts utifrån olika faktorer som författarna anser att företaget bör prioritera. Exempel på väsentliga faktorer som förslagen innefattar är bland annat kostnadsaspekten, volymutnyttjandet och tillämpningen av FIFO. Kostnadsförslagen för lagersystemen är framtagna utifrån stöd från leverantörer, vilket lett till en tydligare kostnadsjämförelse. Utifrån de presenterade förbättringsförslagen, har dessa avgränsats för att till slut kunna komma fram till ett slutgiltigt val. Vid fortsatta studier kring arbetet rekommenderas företaget att investera i ett pallställage som inte endast är en ekonomisk lösning, utan som dessutom löser platsbristen i lagret. Samtidigt lagerhålls samtliga komponenter med väderskydd. Detta kommer slutligen leda till en förbättrad FIFO hantering i FVL som företaget eftersträvar.

This diploma thesis deals with the design of a full pallet storage stacker using the FIFO method. The first part of the thesis contains a research analysis of similar competitive solutions. This is followed by a description of the created conceptual design of the storage stacker. The design includes the choice of speeds and accelerations of stacker movements, which are necessary for the calculations of the tilting, lifting and traveling mechanism. Another part of the thesis is the strength check of the lifting carriage frame. The attachment consists of the drawing documentation of the designed device.