Less-than-truckload industry has a valuable potential for applications of operations research in two areas, network design and efficiency improvement within existing networks. This thesis focuses on the latter, specifically the less-than-truckload terminals where cross docking operations occur. The assignment of incoming trailers to inbound docks is one of the critical decisions that affect the performance of less-than-truckload terminals. This research reviews existing models in literature and introduces an optimal mixed integer quadratic model with the objective of generating assignments that are robust against variability in system parameters such as truck arrival and service times, terminal characteristics and trailer load content. The computational limitations of the optimal model are discussed. A dock assignment heuristic is developed to overcome the computational difficulties reported with the optimal model to solve realistic size problems. It is concluded that the heuristic is generally applicable and is robust against system variably. A dynamic dock assignment heuristic is later introduced to implement the decision process at real time. It is concluded that the dynamic dock assignment heuristic is also robust against system variability. The last part presents a case study that benchmarks the dynamic dock assignment heuristic and existing static assignments at a real terminal. The results show that the dynamic dock assignment heuristic outperforms the static assignment under system variability. Conclusions and future research areas are finally addressed in the last chapter.

In spite of their high technical maturity, load sensing systems (LS) have system-inherent energy losses that are largely due to the operation of parallel actuators with different loads at the same pressure level. Hereby, the pressure compensators of the system are crucial. So far, excessive hydraulic energy has been throttled at these compensators and been discharged as heat via the oil. The research project “Reduction of System Inherent Pressure Losses at Pressure Compensators of Hydraulic Load Sensing Systems” aims to investigate a novel solution of reducing such energy losses. The pressure of particular sections can be increased by means of a novel hydraulic circuit. Therefore, a recovery unit is connected in series with a hydraulic accumulator via a special valve in the reflux of the actuators. The artificially increased pressure level of the section reduces the amount of hydraulic power to be throttled at the pressure compensators. As long as a section fulfills the switching condition of the valve, pressure losses at the respectiv pressure compensator can be reduced. Thus, via a suitable recovery unit excessive energy can be regenerated and can be directed to other process steps eventually.

En av de största utmaningarna i dagens byggbransch är logistikfrågan, fler och fler projekt påverkas av logistikutmaningar och det är av stor vikt att dessa utmaningar granskas och åtgärdas. Allt fler företag har börjat hantera dessa utmaningar med hjälp av olika logistiksamordningsverktyg för att spara tid, få bättre överblick och planering över materialflödet, minska skador med flera. Syftet på detta examensarbete är att undersöka om logistiksamordningsprogrammet Myloc Construction är ett effektivt samordningssystem att använda vid logistikhantering genom att undersöka hur programmet upplevs på tre olika projekt. Författarna har genom denna undersökning som mål kommit fram till om rätt val av logistikmetod gjorts för de tre projekten, vid vilka sorts projekt Myloc Construction ska användas och om Myloc Construction är ett system som Veidekke ska använda för framtida projekt. I dagsläget så pågår ett till- och ombyggnadsprojekt på tre olika huskroppar av Sergelhuset på Sergels torg där Veidekke, NCC och Zengun genomför projektet i en totalentreprenad i samverkan. Alla tre entreprenader använder sig utav Myloc Construction för sina respektive delar i projektet. Undersökningen har baserats på en kombination av olika vetenskapliga metoder såsom intervjuer, enkäter, litteraturstudier, observationer samt elektroniska källor. För att få en djupare förståelse om Myloc Construction har nio personer som använder programmet intervjuats. Enkätundersökningen delades ut till olika användare av programmet för att få en större helhetsbild. På grund av projektets storlek, placering och komplexitet där flera entreprenader samverkar med varandra så är ett logistikprogram nödvändigt. Programmet kan användas till alla typer projekt men är mest nödvändigt till större och mer komplexa projekt. Förutsatt att Myloc fortsätter att uppdatera sin tjänst både på webben och i mobilen så är det något som kan effektivisera logistiken. / One of the biggest challenges in today's construction industry is the logistics issue, at an increasing, projects are being affected by logistic challenges and it is of great importance that these challenges are reviewed and addressed. More and more companies have started to address these challenges with the help of various logistics coordination tools to save time, get a better overall image and planning over the flow of materials, reduce damage to materials and more. The purpose of this thesis is to investigate whether the logistics coordination program Myloc Construction is an effective system to use in logistics management by examining how the program is perceived on three different projects. Through this study, the authors have reached the goal of whether the right choice of logistics method has been made for the three projects, at which kind of project Myloc construction will be used and whether it is a system that Veidekke should use for future projects. At present, a construction and renovation project is under way on three different housing bodies by Sergelhuset at Sergel's square where Veidekke, NCC and Zengun carry out the project in a turnkey contract in collaboration. All three contracts utilize the logistics coordination tool Myloc construction for their respective parts of the project. The study has been based on a combination of various research methods such as interviews, questionnaires, literature studies, observations and electronic sources. To get a deeper understanding of Myloc construction, nine people using the software have been interviewed. The survey was distributed to different users of the program to get a larger overall picture. Due to the size, location and complexity of the project, where several contracts work together, a logistics program is necessary. The program can be used for all types of projects but is most necessary for larger and more complex projects. Provided that Myloc continues to update its service both on the web and on the mobile phone, it is something that Veidekke should use in the future.

Актуальность темы обусловлена необходимостью компаний в условиях конкуренции быстро распознать изменения динамики рынка и своевременно отреагировать на них с целью увеличения прибыли. Научная новизна исследования заключается в поиске путей повышения эффективности бизнес-процессов предприятия на основе SAP-аналитики для туристического бизнеса. Практическая значимость исследования заключается в практическом применении предлагаемого способа повышения эффективности бизнес-процессов в туристическом агентстве и получения экономической выгоды от результата внедрения информационной системы. / The relevance of the topic is due to the need for companies in a competitive environment to quickly recognize changes in market dynamics and timely respond to them in order to increase profits. The scientific novelty of the research lies in finding ways to improve the efficiency of business processes of an enterprise based on SAP analytics for the tourism business. The practical significance of the study lies in the practical application of the proposed method for increasing the efficiency of business processes in a travel agency and obtaining economic benefits from the result of the implementation of the information system.

Improving energy efficiency in buildings is essential for curbing greenhouse gas emissions, addressing climate change, and achieving cost savings while enhancing occupant comfort. This study examines the energy performance of Nordiska Folkhögskolan, a Swedish school building, before and after renovation, benefiting from Sweden's advanced energy-efficienttechnologies and supportive policies. Energy consumption data analysis reveals significant reductions in district heating and electricity usage post-renovation, attributed to enhancements in insulation, heating systems, and energy management. Notably, there is a consistent decline in energy consumption, particularly during winter months, emphasizing the effectiveness of holistic approaches to energy-efficient building design and highlighting the importance of targeted energy efficiency measures in reducing heat losses through the building envelope.  The successful mitigation of energy loss through enhanced insulation and ventilation systems underscores the necessity of comprehensive energy-efficient design strategies. Despite promising outcomes, variations in energy consumption patterns post-renovation require ongoing evaluation and supplementary measures. Recommendations include adopting advanced exterior wall designs, continuous energy monitoring, integrating renewable energy solutions, conducting educational outreach initiatives, and investing in energy-efficient infrastructure. These strategies collectively promote conservation and establish sustainable learning environments, contributing valuable insights into enhancing energy efficiency in school buildings globally.

In this study, an energy audit of a cultural-historical building in a Nordic climate was carried out. The study has been carried out by studying old drawings to calculate ar-eas of the building and taking part in compiled data from the property owner. The building's energy supply and energy losses have been calculated in order to be able to identify areas for improvement and ultimately provide action proposals. For the proposed measures, the idea is to reduce energy use. At the same time, the profita-bility is examined using present value calculation to see if the energy efficiency measures are profitable investments. Several different measures have been investi-gated through literature studies where the potential to make older buildings more energy efficient is great. These show that certain problems arise when the building has a cultural-historical value. These buildings have special rules to preserve the cul-tural-historical value and it is often difficult to get measures that change the appear-ance of the building. Measures that have been calculated more carefully include re-placement of windows and replacement of thermostatic valves in the heating system. Window change possibilities are limited by conservation requirements; the price will therefore be higher and profitability calculations show that it is not profitable to invest in new highly insulating ones. Current changes to thermostatic valves show profitability calculations that such an investment is profitable. No comfort measure-ments were made in the study, but measures such as improving the insulating ability of windows and installing thermostats on heating systems are both factors that will affect thermal comfort for the better. The result from the energy mapping shows that the building's specific energy use is 137 kWh/m2, year. / I den här studien genomfördes en energikartläggning av en kulturhistorisk byggnad i nordiskt klimat. Studien har genomförts genom att studera gamla ritningar för att beräkna areor på byggnaden och tagit del av sammanställda data från fastighetsäga-ren. Byggnadens energitillförsel och energiförluster har beräknats för att kunna identifiera förbättringsområden och till slut ge åtgärdsförslag. För de framförda åt-gärdsförslagen är tanken att minska energianvändningen. Samtidigt undersöks lön-samheten med hjälp av nuvärdeskalkyl för att se om energieffektiviseringsåtgärderna är lönsamma investeringar. Flera olika åtgärder har undersökts genom litteraturstu-dier där potentialen till att energieffektivisera äldre byggnader är stor. Dessa visar att vissa problem uppstår när byggnaden har ett kulturhistoriskt värde. Dessa bygg-nader har speciella regler för att bevara det kulturhistoriska värdet och det är ofta svårt att få göra åtgärder som förändrar byggnadens utseende. Åtgärder som har be-räknats mer noggrant innefattar fönsterbyte och byte till termostatventiler i värme-systemet. Fönstren begränsas av bevarandekrav; priset blir därmed högre och lön-samhetsberäkningar visar att det inte är lönsamt att investera i nya högisolerande så-dana. Gällande byte till termostatventiler visar lönsamhetsberäkningar på att sådan investeringen är lönsam. Inga komfortmätningar gjordes i studien men åtgärder så som att förbättra fönsters isoleringsförmåga och installation av termostater på vär-mesystem är båda faktorer som kommer att påverka den termiska komforten till det bättre. Resultatet från energikartläggningen visar att byggnadens specifika energian-vändning är 137 kWh/m2, år.

This thesis investigates a novel induction machine topology that uses a rotating power electronic converter. Steady-state and dynamic performance of the topology is studied to understand its operational principle. Furthermore the potential of improving its efficiency and power factor is investigated. The topology is referred to as wound rotor induction machine with rotating power electronic converter (WRIM-RPEC).     The WRIM-RPEC topology offers the possibility to magnetize the induction machine from the rotor side by introducing a reactive voltage in the rotor. Thus, the power factor of the machine can be improved. Constant speed variable load operation can be achieved by setting the frequency of the introduced voltage. Two options of rotor winding and converter configuration in the WRIM-RPEC system are investigated. The wound rotor windings can either be open-ended and fed by a three-phase back-to-back converter or Y-connected and fed by a single three-phase converter. The dc-link in both converter configurations contains only a floating capacitor. These two configurations give different dc-link voltages at the same torque and speed.     Two analytical steady-state models of the topology are developed in this thesis. The first model can be used to analyze the operating condition of the motor at specific speed and torque. Particularly, the operating range of speed and torque of the topology is investigated. The second model is used to analyze variable power factor operation, including unity power factor operation. Analytical calculations and measurements are carried out on a 4-pole, 1.8kW induction machine and the results are compared.      A dynamic mathematic model is then developed for the WRIM-RPEC system for the back-to-back converter configuration. The mathematic model is then applied in Matlab/Simulink to study the dynamic performance of the system including starting, loading and phase-shifting. The simulation results are compared with measurements on the 4-pole, 1.8kW induction machine. Moreover, the simulation model using the existing Simulink blocks are studied to compare with the results obtained from the mathematic model. Furthermore, the dynamic performance of the WRIM-RPEC system with the single converter configuration is investigated. In addition, harmonic spectra analysis is conducted for the stator and rotor currents.     In the last part of the thesis, efficiency improvement is investigated on the 4-pole induction machine when it is assumed to drive a pump load. It is shown that the efficiency can be further improved by decreasing the rotor resistance. Due to space constraints it is however difficult to decrease the rotor resistance in a 4-pole induction machine. An investigation is thus carried out on a standard 12-pole, 17.5kW squirrel-cage induction machine with inherent low power factor. The cage rotor is redesigned to a wound rotor to enable the connection of converter to the rotor windings. An analytical model is developed to design the wound rotor induction machine. The machine performance from calculations is then compared with FEM simulations with good agreement. The analytical model is further used to design several WRIMs with different dimensions and rotor slot numbers. Power factor and efficiency improvement is then explored for these WRIMs. A promising efficiency increase of 6.8% is shown to be achievable. / <p>QC 20161111</p>

<p>Cilj ovog istraživanja bio je da se razvije metoda čijim kori&scaron;ćenjem može da se doprinese pobolj&scaron;anju efikasnosti rada poljoprivrednih biogas postrojenja. Da bi se to ostvarilo, izabrani su odgovarajući kriterijumi i parametri. Razvijena je metoda za ocenu efikasnosti, a rezultati dobijeni njenim kori&scaron;ćenjem ukazuju na potrebu za pobolj&scaron;anjem. Razvijena je i metoda za analizu mogućnosti pobolj&scaron;anja, kojom se predlažu mere za ostvarenje pobolj&scaron;anja. U razvoju metoda kori&scaron;ćeni su principi fazi logike i ekspertskih sistema, da se modeluje neodređenost u podacima i koristi ekspertsko znanje za ocenu. Testiranjem metoda, koristeći podatke o radu petnaest postrojenja u Bavarskoj, zaključeno je da su metode primenljive u obliku pomoćnog alata za sprovođenje pobolj&scaron;anja efikasnosti.</p> / <p>The aim of this investigation was to develop a method that can be used<br />for improving the efficiency of agricultural biogas plants. In order to<br />achieve this, appropriate criteria and parameters were selected. The<br />method for assessing the efficiency was developed, which results<br />indicate the need for improvement. The method for analyzing the<br />possibilities of improvement was developed as well, in order to propose<br />measures for improvement. In development of methods, principles of<br />fuzzy logic and expert systems were used, in order to model uncertainty<br />in the data and to use expert knowledge for assessment. According to<br />test results, using data of fifteen biogas plants in Bavaria, it was<br />concluded that methods can be used for efficiency improvement.</p>

Cette thèse traite de la conception d’un convertisseur DC / DC destiné aux véhicules électriques et hybrides (2,5 kW, 400V/14V, 250kHz). Dérivé de la topologie LLC à résonance, ce convertisseur bénéficie des nombreux avantages propres à cette structure particulière. C’est ainsi que le prototype réalisé présente un rendement très élevé, une densité de puissance très forte avec des perturbations EMI très réduites. La première partie de cette thèse est consacrée à l’analyse théorique du circuit LLC afin de dégager un modèle de conversion et une stratégie de contrôle adaptée à l’application visée. Afin de conserver un rendement important sur une large plage de charge, une structure basée sur la mise en parallèle de deux modules LLC est proposée. Une nouvelle stratégie de contrôle à deux boucles est également proposée pour équilibrer le courant entre les deux modules. La seconde partie de la thèse fait appel à la simulation et à l’expérimentation. Il s’agit de minimiser la masse et l’encombrement tout en maximisant le rendement. Un composant magnétique spécial est conçu puis dimensionné pour intégrer le transformateur et diverses inductances de résonance. Ce convertisseur met également en œuvre un système de redressement synchrone robuste avec une compensation de phase, un module de puissance avec une résistance thermique très faible et un système de refroidissement efficace par air. Le rendement maximal mesuré est 95%. Le rendement demeure supérieur à 94% sur une plage de puissance s’étalant de 500 W à 2 kW. La densité de puissance est 1W/cm3. La CEM du convertisseur est développée dans cette thèse. / In this dissertation, a 2.5kW 400V/14V, 250kHz DC/DC converter prototype is developed targeted for electric vehicle/hybrid vehicle applications. Benefiting from numerous advantages brought by LLC resonant topology, this converter is able to perform high efficiency, high power density and low EMI. A first part of this dissertation is the theoretical analysis of LLC: topology analysis, electrical parameter calculation and control strategy. To arrange high output current, this thesis proposes parallel connected LLC structure with developed novel double loop control to realize an equal current distribution. The second part concerns on the system amelioration and efficiency improvement of developed LLC. A special transformer is dimensioned to integrate all magnetic components, and various types of power losses are quantified based on different realization modes and winding geometries to improve its efficiency. This converter also implements a robust synchronous rectification system with phase compensation, a power semiconductor module, and an air-cooling system. The power conversion performance of this prototype is presented and the developed prototype has a peak efficiency of 95% and efficiency is higher than 94% from 500W to 2kW, with a power density of 1W/cm3. The CEM analysis of this converter is also developed in this thesis.

The investigation was initiated because of the high workload of the sellers and, additionally, because the Tunadal sawmill has received low ratings in customer surveys. Thus,  two main approaches are adopted here,  the first being to investigate which of the three methods  of working, namely, market divided flow organization, function organizationand flow organization with collaboration, proves to be the most beneficial. The second is to investigate whether there is an available method to ease the daily work. A literature review has been made in order to determine more efficient ways for the sellers to work in the Tunadal sawmill. During the investigation, an in-depth investigation into the total quality management using a balanced scorecard as a management tool was conducted. To identify the current problems, interviews and workshops were conducted with the department members. A customer survey was sent to the customers in order to obtain some indication in relation to their opinions. The results showed that there are many unnecessary working operations such as control, duplication of work and problem solving. Communication between the various departments and individuals proved to sometimes be poor.  A major reason for the sellers’ problems regarding workload was due to the unavailability of goods on the discharge date. Many benefits are associated with the collaborative flow organization as this increases the holistic view and can assist in relation to communication. The function based method of working would, however, lead to greater isolation of the functions in the business. Very little work regarding identification of problems that occur in the processes exists and focus on working with improvements is limited. It would be advantageous to work with total quality management using the balanced scorecard as a management tool in the flow organization based on cooperation as this also promotes the holistic approach. Keywords:Efficiency improvement, total quality management, balanced / Denna undersökning har initierats eftersom innesäljarna har upplevt att arbetsbelastningen varit hög och att Tunadals sågverk har fått låga betyg i kundundersökningar. Syftet med denna undersökning har varit dels att utreda vilket av de tre arbetsformerna marknadsuppdelad flödesor-ganisation, funktionsorganisation och flödesorganisation med samarbete som är den mest fördelaktiga arbetsformen att använda i förhållande till de problem som finns i dag, dels utreda om det finns något arbetssätt som underlättar det vardagliga arbetet med att administrera försäljningar. Med anledning av detta har en litteraturstudie gjorts i syfte att hitta en effektivare arbetsform och ett effektivare arbetssätt för innesäljarna på Tunadals sågverk. Under denna studie valdes en fördjupning inom offensiv kvalitetsutveckling med balanserat styrkort som styrinstru-ment. För att identifiera problem i dag har intervjuer genomförts med innesäljarna. En kundundersökning har också genomförts för att få en uppfattning om kundernas synpunkter. Resultatet visar att det finns mycket onödiga arbetsmoment, exempelvis kontroll, dubbelarbete och problemlösning. Kommunikationen mellan olika enheter och individer är ibland bristfällig. En av de största orsakerna till innesäljarnas problem med hög arbetsbelastning är att varor inte är färdigtillverkade vid utlastningsdatum. Det sker nästan inget arbete med att identifiera vilka problem som finns i processerna och det utförs endast lite arbete med fokus på förbättringsarbete. Det finns många fördelar med att arbeta i en flödesorganisation med samarbete eftersom denna arbetsform ökar helhetssynen och underlättar kommunikationen. Funktionsorganisa-tionen skulle däremot leda till att funktionerna i verksamheten blir mer isolerade. Det vore fördelaktigt att arbeta med offensiv kvalitetsutveckl-ing med balanserat styrkort som styrinstrument eftersom detta arbets-sätt har många fördelar. Nyckelord: Effektivisering, offensiv kvalitetsutveckling, balanserat styrkort, PDSA-cykeln, släktskapsdiagram, arbetsform.