No description available.

The thesis deals with the Efficient Consumer Response system, which is based on partnership between retailer and his supplier to prepare value added for customer. In the teoretical part of the thesis are mentioned 2 main strategies: Efficient Replenishment and Category management. Practical part of the thesis dedicates usage of the system in practice.

Foraging behavior has recently become a popular area of research with which ethologists, behavioral ecologists, and experimental psychologists converge their traditionally separate disciplines into a more multidisciplinary framework. Ethologists and behavioral ecologists usually study foraging as it occurs in the natural environment or the "field," while experimental psychologists contrive laboratory simulations of foraging and make the assumption, sometimes incorrectly, that generalization occurs across settings, situations, and species. Scientific advances are now beginning to occur in the ability of laboratory researchers to better simulate foraging as it occurs in the field. Field researchers are also becoming more willing to accept these findings as important. The purpose of this dissertation was to use a laboratory analogue of foraging behavior to examine the effects of prey vulnerability, density, and prey-patch replenishment on the number of prey rejections and switches between patches. This analogue may have more biological validity than previous simulations in the operant laboratory by simulating conditions of replenishing and depleting patches under adjusting (progressive and regressive) random-ratio schedules of reinforcement. Three experiments were conducted. The first examined the effects of response-cost on acceptability of prey items offered. Results indicated that as the cost of obtaining one prey item increased while the cost of another was held constant, subjects consistently pursued the lower-cost prey and rejected higher-cost prey at increasing probability ratios of 1:3, 1:10, and 1:15. The second experiment covaried response cost (vulnerability) with the probability of encounter (density) for two prey types and evaluated their effects on the acceptability of prey. This experiment showed that when the density of the low-cost prey increased (p = .66), the subjects were more selective. Subjects were less selective when the density of the low-cost prey decreased (p = .33). In the third experiment, prey patches were replenished at reinforcer-determined (regressive random ratio) baseline rates and compared to several fixed-time schedules of patch replenishment. Results of Experiment III indicated no major differences in patch use behaviors (number of switches between patches). The validity and utility of this simulation was discussed as a useful model for the experimental analysis of foraging behavior.

No description available.

Coordinated lot sizing problems, which assume a joint setup is shared by a product family, are commonly encountered in supply chain contexts. Total system costs include a joint set-up charge each time period any item in the product family is replenished, an item set-up cost for each item replenished in each time period, and inventory holding costs. Silver (1979) and subsequent researchers note the occurrence of coordinated replenishment problems within manufacturing, procurement, and transportation contexts. Due to their mathematical complexity and importance in industry, coordinated lot-size problems are frequently studied in the operations management literature. In this research, we address both uncapacitated and capacitated variants of the problem. For each variant we propose new problem formulations, one or more construction heuristics, and a simulated annealing metaheuristic (SAM). We first propose new tight mathematical formulations for the uncapacitated problem and document their improved computational efficiency over earlier models. We then develop two forward-pass heuristics, a two-phase heuristic, and SAM to solve the uncapacitated version of the problem. The two-phase and SAM find solutions with an average optimality gap of 0.56% and 0.2% respectively. The corresponding average computational requirements are less than 0.05 and 0.18 CPU seconds. Next, we propose tight mathematical formulations for the capacitated problem and evaluate their performance against existing approaches. We then extend the two-phase heuristic to solve this more general capacitated version. We further embed the six-phase heuristic in a SAM framework, which improves heuristic performance at minimal additional computational expense. The metaheuristic finds solutions with an average optimality gap of 0.43% and within an average time of 0.25 CPU seconds. This represents an improvement over those reported in the literature. Overall the heuristics provide a general approach to the dynamic demand lot-size problem that is capable of being applied as a stand-alone solver, an algorithm embedded with supply chain planning software, or as an upper-bounding procedure within an optimization based algorithm. Finally, this research investigates the performance of alternative coordinated lotsizing procedures when implemented in a rolling schedule environment. We find the perturbation metaheuristic to be the most suitable heuristic for implementation in rolling schedules.

The area of order picking has been widely studied but still there is no general approach covering all the potential variables of a unique case. Optimizing the product placement is a useful way to improve order picking through reduced travel distances and goes hand in hand with an appropriate batching strategy and routing policy. The existing methods are of mathematical basis and can be costly to implement and it is therefore necessary to develop a non-mathematical approach that can be used for distribution centers and in this particular case, the warehouse of a mail order company. Literature is reviewed to investigate the current situation of a large Swedish mail order retailer for the development of a unique product assignment strategy, taking into consideration potential variables. It was found out that a lot of trade-offs are being done all the time between travel distances of the SKUs. Also, it was found out that “cart blocking” might be a potential problem when using a turnover-based storage assignment strategy.

Thesis (MScFor (Forest and Wood Science))--Stellenbosch University, 2008. / This study sought to examine the effects of soil fertility replenishment (SFR) adoption on household security and poverty reduction in smallholder farming households of central and southern Malawi by assessing food security, asset status, and household income generating activities in Kasungu and Machinga Districts during 2007. The results showed that households had been able to significantly increase maize production by an extra 382 kg per year in Kasungu and 242 kg per year in Machinga Districts, which constitutes approximately 35% and 22% of average household maize requirements for the year for each district, respectively. This reduced the critical annual hunger periods from 3.46 months to 2.80 months per year in Kasungu and from 4.31 months to 3.75 months in Machinga. Respondents also reported a significant increase in assets and an increase in income. Despite these positive changes, households were found to still be living in extreme poverty. Selling physical assets was the most common response to shocks and any increase in income was allocated to the purchase of food, household supplies, and other items necessary to immediate survival. This study revealed that while food security is paramount to the sustainable livelihoods of smallholder farmers, livelihood security and poverty reduction depend on more than increased food production. SFR technologies are fulfilling their primary role as a means to food security, but their adoption does not lead to significant livelihood improvements. Achieving lasting impacts requires that initiatives take an integrated approach and address not only household food production, but the multifaceted dynamics of social institutions, markets/economy, and policy. The long-term impacts of the current agroforestry programs in the study areas will emerge only with time. Livelihood improvements will depend on several factors. First, market inefficiencies must be remedied and economic barriers must be broken down. Second, the challenges identified by the respondents, especially access to resources and training, need to be addressed in a participatory way that promotes education and empowerment. As these two issues are tackled, households will become better equipped to manage the complexities that arise from SFR adoption and livelihood diversification. It is recommended that future research and initiatives should focus on identifying and removing economic barriers to markets, addressing farmeridentified challenges such as access to seed, water, and education and training, supporting households in managing multiple livelihood strategies, and continuing research to identify appropriate agroforestry species and technologies.

Please read the abstract in the section 00front of this document. / Thesis (PhD)--University of Pretoria, 2010. / Industrial and Systems Engineering / unrestricted

<p>Ericsson AB har en produktionsenhet i Gävle (Sverige), CDC Gävle. Denna enhet är indelad i två fabriker, Skolgången och Avaström. På Skolgången monteras WCDMA radiobasstationer (3G) och på Avaström GSM radiobasstationer (2G).</p><p>CDC Gävle har idag ett stort returflöde av emballage från inkommande monteringsmaterial. Det förekommer också många störningar i materialförsörjningen till monteringen. CDC Gävle har beslutat att på sikt ska allt material som idag finns på lager befinna sig på hubbar.</p><p>Syftet med examensarbetet var att undersöka påfyllnaden av monteringsmaterial till linan. Påfyllnad skulle ske direkt mot linan. Resultatet av arbetet blev en teoretisk försörjningsmodell som byggde på att materialet kom från hubbar. Försörjningsmodellen skulle ta hänsyn till nuvarande systemlandskap samt att det skulle ske på ett så kostnads- och utrymmeseffektivt sätt som möjligt. Den skulle också se över problemen med emballage och störningarna i materialflödet.</p><p>Arbetet skulle besvara följande centrala frågor:</p><p>• Hur bör materialet fördelas på hubbarna?</p><p>• Vilka lastbärare är lämpliga vid levereras till linan?</p><p>• Vilka förändringar kan komma att krävas av befintliga system, arbetsmetodik samt vilka krav ska ställas?</p><p>• Var och hur bör omplock av material ske?</p><p>• Hur kommer materialflödet att se ut från hubb till monteringslina?</p><p>Arbetet har bedrivits genom datainsamling på CDC Gävles olika anläggningar. Det genomfördes även ett flertalet studiebesök för att se hur andra producerande företag arbetade med liknande frågor. Under arbetsgången har det skett kontinuerliga litteraturstudier.</p><p>Författarna belyste och tog fram ett flertal parametrar som anses avgörande vid utformningen av en ny försörjningsmodell. CDC Gävle måste besluta hur dessa parametrar ska lösas innan en fullständig implementering av hubbar kan börja. Arbetet resulterade i en försörjningsmodell som är generell för både WCDMA och GSM. Arbetet tar också upp hur hubben bör arbeta, vilka funktioner den ska innehålla samt vart den bör lokaliseras. Vidare rekommenderas lämpliga lastbärare och vilka arbetssätt som är lämpliga för CDC Gävle.</p><p>Ett av de största problemen i arbetet var att ta hänsyn till de speciella materialflödena som CDC Gävle har, detta gällde bl a reklamation och enhetspackade artiklar. Den centrala parametern i hela försörjningsmodellen var frystiden. Frystiden är den tidsperiod från att kunden inte kan ändra sin order till ordern startas på monteringen. Om det inte existerar någon frystid kommer inte hubben hinna plocka fram och leverera det material som CDC Gävle behöver.</p><p>Författarna bedömer att det finns goda möjligheter att flytta befintliga lager till hubbar. Det bör dock genomföras ett flertal piloter med olika sorters material innan man går vidare.</p> / <p>Ericsson AB has a production unit in Gävle (Sweden), CDC Gävle. The unit is divided into two facilities, Skolgången and Avaström. WCDMA (3G) Radio Base Stations are assembled at Skolgången and GSM (2G) Radio Base Stations are assembled at Avaström.</p><p>Today CDC Gävle has a major return flow of packing from received assembly material. There also exist several disruptions in the material supply to the assembly. CDC Gävle has decided that in the long term all material, which today is stored in the warehouse, will be stored in hubs.</p><p>The purpose of the thesis work was to investigate the replenishment of material to the line. Replenishment was to be made directly to line. The result of the thesis work became a theoretical supply model that was based on the material arriving from hubs. The supply model had to consider the present system environment and also be as cost and area efficient as possible. It was also supposed to look at the problems with packing and disruptions within the material flow.</p><p>The thesis work was to answer the following essential questions:</p><p>• How should the material be allocated to the hubs?</p><p>• Which load-carriers are appropriate on delivery to the line?</p><p>• What changes could be required of the present systems, working methods and also what requirements are to be made?</p><p>• Where and how should the re-arrangement of material be done?</p><p>• What will the material flow look like from hub to assembly line?</p><p>The thesis work has been carried out by the collection of data at CDC Gävle’s different facilities. Several study visits were conducted to see how other producing companies worked with similar questions. During the work process there have been continuous literature studies.</p><p>The authors elucidated and compiled several parameters, which were considered crucial in the design of a new supply model. CDC Gävle must decide how these parameters will be solved before a full-scale implementation of hubs can begin. The result of the thesis work was a supply model, which is common to both WCDMA and GSM. The thesis work also covers how the hub should work, which functions it will contain and where it should be located. Further, more suitable load-carriers and ways of working for CDC Gävle are recommended.</p><p>One of the biggest problems was to take into consideration of the special material flows, which CDC Gävle has; amongst those concerned were the claims flow and the unit-packed articles. The essential parameter in the whole supply model was the frozen horizon. The frozen horizon is the time period from when a customer cannot change the order to when the order is started in the assembly. If there is no frozen horizon, the hub will not have enough time to take out and deliver the material, that CDC Gävle need. The authors’ opinion is that there are good possibilities of moving the present warehouse to hubs. However several pilots should be conducted with different kinds of materials before any further step is taken.</p>

<p>GNT Group is a Nordic/Baltic wholesaler that distributes products in the IT, entertainment and home electronics sector. GNT is facing problems with inaccurate inventory levels which can lead to unnecessarily high inventory carrying costs or lost sales. Currently the decisions about when and how many to order are made somewhat arbitrarily by the responsible personnel. Their decisions are based only on some brief sales history and on experience. </p><p>GNT wants to develop its ERP system to be able to support the purchaser in these and other related decisions. The purpose of this thesis is to give suggestions to what decisions the ERP system should support and how these decisions can be made. </p><p>The three main tasks in this thesis are to suggest how to calculate the optimal order quantity, how to calculate the optimal ordering point and how to decide whether it can be profitable to store an article in only one of GNT’s warehouses. </p><p>The suggested solution is based on a volume value/demand frequency classification which also takes an item’s life cycle characteristics into consideration. For the different classes suitable calculations and decisions are suggested concerning the three main tasks and issues related to them.</p>