Counting independent sets in graphs with bounded bipartite pathwidth

The Glauber dynamics can efficiently sample independent sets almost uniformly at random in polynomial time for graphs in a certain class. The class is determined by boundedness of a new graph parameter called bipartite pathwidth. This result, which we prove for the more general hardcore distribution with fugacity λ, can be viewed as a strong generalisation of Jerrum and Sinclair’s work on approximately counting matchings. The class of graphs with bounded bipartite path-width includes line graphs and claw-free graphs, which generalise line graphs. We consider two further generalisations of claw-free graphs and prove that these classes have bounded bipartite pathwidth

Doseringsmaskin Preplant

This report presents a thesis project conducted by two students at Mälardalens högskola. The project covers 15 points in industrial design and was conducted during April to June 2014. The principal of the thesis works at Plastic Produkter. The assignment was to develop equipment for an effective way to dose, mix silicon, fill a special designed plastic bag and then seal it. The bag is then formed into a breast model.When a customer for various reasons decides to do a breast augmentation or a breast reconstruction, there may be doubt or uncertainty about the result. The idea of this product is to show the client and the client’s environment how the result of a future breast surgery would look like.The process began with a specification of demands and a functional analysis to define the issue. Once the problem was defined a competitor analysis was made to get an idea of how the competitors solve similar problems. The authors concluded that there were no obvious competitors, but there were products with similar purpose.The authors chose to start focus on how the mechanism would work. A partition of the machine made that a generation of ideas could be made on each separate part and then they could be combined into several concepts. A Pugh’s matrix and a QFD were made on the concepts for the mechanism to decide which concepts that should be developed. The winning mechanism concept was then combined with the remaining concepts parts that were selected. The final concept was a machine that is simple and easy to use, which meets the specified requirements.Tests and calculations were made to support the decisions that were taken. When the final concept was fully developed and tested, a casing was created which was formed after the inside of the machine. The casing is designed to fit into the customer environment and is developed for a first production. A 3D sketch of the final concept was made in SolidWorks to easily get a visual image of the concept. The entire machine and its components are presented in the results. Concept care was made on the machine to get low production costs and to make it easy to assembly. To locate and eliminate any future risks, a failure modes and effects analysis called FMEA was made. To easily evaluate the dynamic of the team and the process of the project, the team used an evaluation tool called PIPS. This gave an overall look of that the group assignment worked well throughout the process. Even if the project was in industrial design, it was a lot of construction that was needed to process. This meant that the project took a different and better direction than expected and gave the authors a greater overview of how the machine would work. The authors believe that the goals of the thesis were achieved well in this project

Framtagning av en ergonomisk produkt för servering av dryck på flygplan : Fallstudie hos August Lundh

To prevent damage to the cabin crew an optimal coffee- and teapot in a number of aspects in airline catering was developed, so called “SAS-kannan”. It was launched in 1980 and has been manufactured in over 300 000 copies, which has worn out the mold and it is in need of replacement. The mold is advanced and it will be expensive to manufacture a new one. August Lundh who is the manufacture of “SAS-kannan” today, want to develop a new product for serving drinks with a cost-effective manufacturing. It should involve the positive qualities on the “SAS-kannan” and be adapted to today's airline catering. The objective of the thesis was to develop an ergonomic and functional product for serving cold drinks with cost-effective production and the adaptation to today's storage trolleys on aircrafts. The research began with a comprehensive theoretical framework consisting of scientific articles and academic approved books. Interviews were made to complement the theoretical framework and primary data was collected. All the gathered information was examined in the next step to ensure the validity and reliability. A case study was conducted at August Lundh by a product development that was based on the examined information. To do more detailed tests 3Dprintings were created of each development. The result was a pitcher that is designed to enable an uncomplicated and ergonomic use. It is also adapted for efficient and stable storage in the ATLASboxes, easy filling of the beverage and washing. The pitcher holds 1.5 liters and is a perfect combination of the number of servings, refills of the pitcher and a low weight. The pitcher is made with injection molding and is made out of the Bisfenol A free plastic Tritan. The grip is designed to give the pitcher an ergonomic use for different sized hands and it is symmetrical to allow equal use of both left and right handed. The spout provides a controlled and even beam, and a drip free serving by cutting the beam properly. The spout is designed so that the pitcher only needs to be tilted 90 degrees from an upright position to be emptied. The lid is a separate part which is put on the pitcher with press-fit and it helps to control the beam during serving and to prevent spills in case of turbulence. The authors believe that the objective has been accomplished by a thorough theoretical framework and an empirical study through interviews and a case study.För att förhindra skador på kabinpersonal utvecklades SAS-kannan som var en optimal kaffe- och tekanna i ett flertal aspekter inom flygcatering. Den lanserades på 1980-talet och har idag tillverkats i över 300 000 exemplar vilket har medfört att formverktyget blivit slitet och är i behov av att bytas ut. Det befintliga formverktyget är avancerat och det blir dyrt att tillverka ett nytt. August Lundh som idag tillverkar SAS-kannan vill därför utveckla en ny produkt för servering av dryck med en kostnadseffektiv tillverkning. Den ska kunna jämföras med SASkannans positiva egenskaper och vara anpassad för dagens flygcatering. Syftet med examensarbetet var att ta fram en ergonomisk och funktionell produkt för servering av kall dryck med kostnadseffektiv tillverkning samt anpassning till dagens förvaring i serveringsvagnar på flygplan. Forskningsprocessen påbörjades med en omfattande teoretisk referensram bestående av vetenskapliga artiklar och akademiskt godkända böcker. Intervjuer gjordes för att komplettera den teoretiska referensramen och primärdata samlades in. All insamlad information granskades i nästa steg för att säkerställa validiteten och reliabiliteten. En fallstudie utfördes hos August Lundh i form av en produktutveckling som var baserad på den granskade informationen. För att kunna göra utförligare tester skapades 3D-utskrifter av varje utveckling. Resultatet blev en kanna som är utformad för att möjliggöra en enkel och ergonomisk användning. Den är även anpassad för effektiv och stabil förvaring i ATLAS-lådor, enkel påfyllning av dryck samt rengöring. Då kannan rymmer 1,5 liter ger det en perfekt kombination av antal serveringar, påfyllningar av kannan samt en låg vikt. Kannan är formsprutad och är tillverkad i den Bisfenol A-fria plasten Tritan. Greppet är utformat för att ge kannan en ergonomisk användning för olika stora händer och är symmetrisk för att möjliggöra lika användning av både höger- och vänsterhänta. Pipen ger en kontrollerad och jämn stråle samt en droppfri servering genom att skära av strålen ordentligt. Pipen är utformad så att kannan endast behöver vinklas 90 grader från upprätt läge för att kunna tömmas. Locket är en separat del som sätts på kannan med presspassning och hjälper till att kontrollera strålen under servering samt förhindra spill vid eventuell turbulens. Författarna anser att syftet har uppfyllts genom att en grundlig teoretisk referensram och en empirisk studie genom intervjuer och en fallstudie utfördes

Doseringsmaskin Preplant

This report presents a thesis project conducted by two students at Mälardalens högskola. The project covers 15 points in industrial design and was conducted during April to June 2014. The principal of the thesis works at Plastic Produkter. The assignment was to develop equipment for an effective way to dose, mix silicon, fill a special designed plastic bag and then seal it. The bag is then formed into a breast model.When a customer for various reasons decides to do a breast augmentation or a breast reconstruction, there may be doubt or uncertainty about the result. The idea of this product is to show the client and the client’s environment how the result of a future breast surgery would look like.The process began with a specification of demands and a functional analysis to define the issue. Once the problem was defined a competitor analysis was made to get an idea of how the competitors solve similar problems. The authors concluded that there were no obvious competitors, but there were products with similar purpose.The authors chose to start focus on how the mechanism would work. A partition of the machine made that a generation of ideas could be made on each separate part and then they could be combined into several concepts. A Pugh’s matrix and a QFD were made on the concepts for the mechanism to decide which concepts that should be developed. The winning mechanism concept was then combined with the remaining concepts parts that were selected. The final concept was a machine that is simple and easy to use, which meets the specified requirements.Tests and calculations were made to support the decisions that were taken. When the final concept was fully developed and tested, a casing was created which was formed after the inside of the machine. The casing is designed to fit into the customer environment and is developed for a first production. A 3D sketch of the final concept was made in SolidWorks to easily get a visual image of the concept. The entire machine and its components are presented in the results. Concept care was made on the machine to get low production costs and to make it easy to assembly. To locate and eliminate any future risks, a failure modes and effects analysis called FMEA was made. To easily evaluate the dynamic of the team and the process of the project, the team used an evaluation tool called PIPS. This gave an overall look of that the group assignment worked well throughout the process. Even if the project was in industrial design, it was a lot of construction that was needed to process. This meant that the project took a different and better direction than expected and gave the authors a greater overview of how the machine would work. The authors believe that the goals of the thesis were achieved well in this project

Regardless of gender : A qualitative study on male preschool teachers´ contributions to children´s gender construction

Syftet med föreliggande studie är att studera hur manliga förskollärare bidrar till barns konstruktion av genus med ett särskilt fokus på barns lika rättigheter och möjligheter oavsett könstillhörighet. Studien är av kvalitativ karaktär med utgångspunkt i det socialkonstruktionistiska perspektivet. Materialet till studien har samlats in genom skriftliga intervjuer med fem manliga förskollärare. Resultatet visar på att de förekommer en omedvetenhet och motstridighet hos de manliga förskollärarna kring könets betydelse för barns konstruktion av genus. Resultatet visar även att det råder en stor osäkerhet kring jämställdhetens betydelse och innebörd i förskolan vilket försvårar arbetet med att främja alla barns lika rättigheter och möjligheter.