Improvement of Operational Efficiency effectiveness (OEE) using Six Sigma DMAIC Methodology — Case Bottomer line AD2378

Overall Equipment Effectiveness (OEE) is the key metric of operational excellence. OEE monitors the actual performance of equipment relative to its performance capabilities under optimal manufacturing conditions. It looks at the entire manufacturing environment measuring, in addition to the equipment availability, the production efficiency while the equipment is available to run products, as well as the efficiency loss that results from scrap, rework, and yield losses. The analysis of the OEE provides improvement opportunities for the operation. One of the tools used for OEE improvement is Six Sigma DMAIC methodology which is a set of practices originally developed to improve processes by eliminating defects. It asserts the continuous efforts to reduce variation in process outputs as key to business success, as well as the possibility of measurement, analysis, improvement and control of manufacturing and business processes. In the case of the Bottomer line AD2378 in Papsac Maghreb Casablanca plant, the OEE figures reached 48.65 %, which is below the accepted OEE group performance. This required immediate actions to achieve OEE improvement. This Master thesis focuses on the application of Six Sigma DMAIC methodology in the OEE improvement on the Bottomer Line AD2378 in Papsac Maghreb Casablanca plant. First, the Six Sigma DMAIC and OEE usage in operation measurement will be discussed. Afterwards, the different DMAIC phases will allow the identification of improvement focus, the identification of OEE low performance causes and the design of improvement solutions. These will be implemented to allow further tracking of improvement impact on the plant operations.

Operational sex ratio, sexual conflict and the intensity of sexual selection.

Modern sexual selection theory indicates that reproductive costs rather than the operational sex ratio predict the intensity of sexual selection. We investigated sexual selection in the polygynandrous common lizard Lacerta vivipara. This species shows male aggression, causing high mating costs for females when adult sex ratios (ASR) are male-biased. We manipulated ASR in 12 experimental populations and quantified the intensity of sexual selection based on the relationship between reproductive success and body size. In sharp contrast to classical sexual selection theory predictions, positive directional sexual selection on male size was stronger and positive directional selection on female size weaker in female-biased populations than in male-biased populations. Thus, consistent with modern theory, directional sexual selection on male size was weaker in populations with higher female mating costs. This suggests that the costs of breeding, but not the operational sex ratio, correctly predicted the strength of sexual selection.

Operational Cost Reduction in WDM Networks using Lighttours

Wavelength division multiplexing (WDM) networks have been adopted as a near-future solution for the broadband Internet. In previous work we proposed a new architecture, named enhanced grooming (G+), that extends the capabilities of traditional optical routes (lightpaths). In this paper, we compare the operational expenditures incurred by routing a set of demands using lightpaths with that of lighttours. The comparison is done by solving an integer linear programming (ILP) problem based on a path formulation. Results show that, under the assumption of single-hop routing, almost 15% of the operational cost can be reduced with our architecture. In multi-hop routing the operation cost is reduced in 7.1% and at the same time the ratio of operational cost to number of optical-electro-optical conversions is reduced for our architecture. This means that ISPs could provide the same satisfaction in terms of delay to the end-user with a lower investment in the network architecture

The Effect of Operational Disturbances on Reliability and Operation Time Distribution of NCmachine Tools in FMS

This thesis concentrates on studying the operational disturbance behavior of machine tools integrated into FMS. Operational disturbances are short term failures of machine tools which are especially disruptive to unattended or unmanned operation of FMS. The main objective was to examine the effect of operational disturbances on reliability and operation time distribution for machine tools. The theoretical part of the thesis covers the fimdamentals of FMS relating to the subject of this study. The concept of FMS, its benefits and operator's role in FMS operation are reviewed. The importance of reliability is presented. The terms describing the operation time of machine tools are formed by adopting standards and references. The concept of failure and indicators describing reliability and operational performance for machine tools in FMSs are presented. The empirical part of the thesis describes the research methodology which is a combination of automated (ADC) and manual data collection. By using this methodology it is possible to have a complete view of the operation time distribution for studied machine tools. Data collection was carried out in four FMSs consisting of a total of 17 machine tools. Each FMS's basic features and the signals of ADC are described. The indicators describing the reliability and operation time distribution of machine tools were calculated according to collected data. The results showed that operational disturbances have a significant influence on machine tool reliability and operational performance. On average, an operational disturbance occurs every 8,6 hours of operation time and has a down time of 0,53 hours. Operational disturbances cause a 9,4% loss in operation time which is twice the amount of losses caused by technical failures (4,3%). Operational disturbances have a decreasing influence on the utilization rate. A poor operational disturbance behavior decreases the utilization rate. It was found that the features of a part family to be machined and the method technology related to it are defining the operational disturbance behavior of the machine tool. Main causes for operational disturbances were related to material quality variations, tool maintenance, NC program errors, ATC and machine tool control. Operator's role was emphasized. It was found that failure recording activity of the operators correlates with the utilization rate. The more precisely the operators record the failure, the higher is the utilization rate. Also the FMS organizations which record failures more precisely have fewer operational disturbances.

Balancing effluent quality, economic cost and greenhouse gas emissions during the evaluation of (plant-wide) control/operational strategies in WWTPs

The objective of this paper was to show the potential additional insight that result from adding greenhouse gas (GHG) emissions to plant performance evaluation criteria, such as effluent quality (EQI) and operational cost (OCI) indices, when evaluating (plant-wide) control/operational strategies in wastewater treatment plants (WWTPs). The proposed GHG evaluation is based on a set of comprehensive dynamic models that estimate the most significant potential on-site and off-site sources of CO2, CH4 and N2O. The study calculates and discusses the changes in EQI, OCI and the emission of GHGs as a consequence of varying the following four process variables: (i) the set point of aeration control in the activated sludge section; (ii) the removal efficiency of total suspended solids (TSS) in the primary clarifier; (iii) the temperature in the anaerobic digester; and (iv) the control of the flow of anaerobic digester supernatants coming from sludge treatment. Based upon the assumptions built into the model structures, simulation results highlight the potential undesirable effects of increased GHG production when carrying out local energy optimization of the aeration system in the activated sludge section and energy recovery from the AD. Although off-site CO2 emissions may decrease, the effect is counterbalanced by increased N2O emissions, especially since N2O has a 300-fold stronger greenhouse effect than CO2. The reported results emphasize the importance and usefulness of using multiple evaluation criteria to compare and evaluate (plant-wide) control strategies in a WWTP for more informed operational decision making

Evaluación de la psicopatología del preescolar mediante el Early Childhood Inventory-4 (ECI-4): concordancia entre padres y maestros.= Assessment of psychopathology in preschool age children through the Early Childhood Inventory-4 (ECI-4): Agreement among parents and teachers

El objetivo principal de este estudio es conocer la concordancia entre informantes, padres y maestros, en cada una de las dimensiones o categorías diagnósticas del Early Childhood Inventory-4 (ECI-4). Además, se pretende analizar la influencia de la presencia de problemas de salud en los padres en la descripción y valoración de la conducta de una muestra de 204 alumnos de preescolar (3 a 6 años) de perfiles socioeconómicos diferentes. Los resultados indican que los padres tienden a valorar con mayor severidad los síntomas, observándose una mayor concordancia entre informantes en los relativos a los trastornos del desarrollo

A cross-border VMI to Russia and cultural impacts to the implementation

VMI (Vendor managed inventory) is a collaboration model between a supplier and a customer, where a supplier has the responsibility of the inventory replenishments. The tightened competition forces companies to collaborate, and VMI is a simple method to cooperate. The aim of this study was to create a cross-border VMI model from Finland to Russia in the case company. However, the cultural differences between the countries produce problems and therefore the cultural impacts to the model and implementation were taken into account. This study includes two parts: the first framework consists of operational principles, benefits, risks, criteria and success factors of VMI and the second concentrates on cultural aspects of the process change. As a result, an operating model for case company’s supply chain was created. In addition, the suggestions for avoiding the cultural impacts in the implementation were given.

Improving inventory management

Having inventory to cover from all possible problems would increase the inventory level indefinitely in accordance with the standard deviation. If the materials in stock are not used, but kept just to be on the safe side, they are waste. The main objective of this study was to find out, how much inventory is required to cover the requirements, without causing delivery problems towards the end-customers, and how the inventory could be controlled efficiently. Several improvements were made in the controlling principles, and the inventory level was quickly decreased by more than 30 %, and kept on the reached level. The suitability of kanban control was investigated, and it was eventually taken into some use. A great advantage was found in the new procedures in securing the supply. The requests for quotations were diversified, and the faulty basis was corrected. Thus, the inventory surplus would later be avoided, and at the same time, a lot of valuable time was saved from daily routines to further improvement projects.

Hipsometric relationship modeling using data sampled in tree scaling and inventory plots

This work evaluated eight hypsometric models to represent tree height-diameter relationship, using data obtained from the scaling of 118 trees and 25 inventory plots. Residue graphic analysis and percent deviation mean criteria, qui-square test precision, residual standard error between real and estimated heights and the graybill f test were adopted. The identity of the hypsometric models was also verified by applying the F(Ho) test on the plot data grouped to the scaling data. It was concluded that better accuracy can be obtained by using the model prodan, with h and d1,3 data measured in 10 trees by plots grouped into these scaling data measurements of even-aged forest stands.