Ohutlevyosien valmistuskustannukset ja kansainvälinen hankintastrategia

Työn tarkoituksena on kehittää hankinnan päätöksentekoa tukeva ohutlevyosien valmistuskustannusten laskentamenetelmä toimintolaskentaan pohjautuen. Laskentamenetelmä koostuu valmistukseen kuluvan ajan laskennassa käytettävistä funktioista sekä konetuntihinnoista. Hankintatoimen päätöksistä käsitellään toimittajanvalintaa, jossa yhtenä vaihtoehtona on hankkiminen Kiinasta. Toimittajanvalinnan kriteereitä ovat tällöin hankintahinnan lisäksi kuljetuskustannukset, laatu sekä toimitusvarmuus. Myös kansainvälisen hankinnan Kiinasta erityispiirteitä käsitellään. Hankkiminen Kiinasta koetaan vielä melko ongelmallisena etenkin laadun ja toimitusvarmuuden osalta. Erityisen huomioitavaa on, että hankintahintojen alhaisuus on osakohtaista. Suurin riski hankinnan kannattavuudelle aiheutuu valuuttakursseista. Osto-organisaation yhteistyötä alihankkijoiden sekä muiden osastojen kanssa parantamalla voidaan välttää hankittavien ohutlevyosien laatuongelmia. Suomalaisten alihankkijoiden kanssa kustannuslaskentamallia avoimeen hinnoitteluun soveltamalla hankintakustannuksia voidaan alentaa.

Merchandising Strategies and Retail Performance for Seasonal Fashion Products

This study presents mathematical methods for evaluation of retail performance with special regard to product sourcing strategies. Forecast accuracy, process lead time, offshore / local sourcing mix and up front / replenishment buying mix are defined as critical success factors in connection with sourcing seasonal products with a fashion content. As success measures, this research focuses on service level, lost sales, product substitute percentage, gross margin, gross margin return on inventory and mark down rate. The accuracy of demand forecast is found to be a fundamental success factor. Forecast accuracy depends on lead time. Lead times are traditionally long and buying decisions are made seven to eight months prior to the start of the selling season. Forecast errors cause stockouts and lost sales. Some of the products bought for the selling season will not be sold and have to be marked down and sold at clearance, causing loss of gross margin. Gross margin percentage is not the best tool for evaluating sourcing decisions and in the context of this study gross margin return on inventory, which combines profitability and assets management, is used. The findings of this research suggest that there are more profitable ways of sourcing products than buying them from low cost offshore sources. Mixing up front and inseason replenishment deliveries, especially when point of sale information is used for improving forecast accuracy, results in better retail performance. Quick Response and Vendor Managed Inventory strategies yield better results than traditional up front buying from offshore even if local purchase prices are higher. Increasing the number of selling seasons, slight over buying for the season in order to

Sensor Fusion of Proprioception, Force and Vision in Estimation and Robot

Sensor-based robot control allows manipulation in dynamic environments with uncertainties. Vision is a versatile low-cost sensory modality, but low sample rate, high sensor delay and uncertain measurements limit its usability, especially in strongly dynamic environments. Force is a complementary sensory modality allowing accurate measurements of local object shape when a tooltip is in contact with the object. In multimodal sensor fusion, several sensors measuring different modalities are combined to give a more accurate estimate of the environment. As force and vision are fundamentally different sensory modalities not sharing a common representation, combining the information from these sensors is not straightforward. In this thesis, methods for fusing proprioception, force and vision together are proposed. Making assumptions of object shape and modeling the uncertainties of the sensors, the measurements can be fused together in an extended Kalman filter. The fusion of force and visual measurements makes it possible to estimate the pose of a moving target with an end-effector mounted moving camera at high rate and accuracy. The proposed approach takes the latency of the vision system into account explicitly, to provide high sample rate estimates. The estimates also allow a smooth transition from vision-based motion control to force control. The velocity of the end-effector can be controlled by estimating the distance to the target by vision and determining the velocity profile giving rapid approach and minimal force overshoot. Experiments with a 5-degree-of-freedom parallel hydraulic manipulator and a 6-degree-of-freedom serial manipulator show that integration of several sensor modalities can increase the accuracy of the measurements significantly.