Multilevel techniques and learning automata for the Maximum Satisfiability (MAXSAT) problem

The Maximum Satisfiability (MAXSAT) Problem is a propositional logic and an optimization based problem that has great importance in the theoretical and practical domain. In the recent years MAXSAT has risen great interest in the industry. Example problems from the industry that can be encoded as MAXSAT problems are circuit design and debugging, hardware verification, bioinformatics and scheduling. These kind of problems often tend to be large and increase exponentially with the problem size, and therefore algorithms for solving such problems incorporate different techniques and methods to solve the problems in a smart and efficient manner. In this thesis we introduce a range of algorithms that extend the well-known Stochastic Local Search (SLS) algorithm called WalkSAT. WalkSAT is extended with the multilevel paradigm and Learning Automata. The multilevel paradigm is a technique that splits large and difficult problems into smaller problems. These problems are expectedly less complex and therefore easier to solve. Learning Automata are a branch of machine learning that can be seen as a decision-making entity that is employed in an unknown environment. Through feedback from the environment the Learning Automata try to learn the optimal actions. The core of this thesis is the observations and findings of how these dissimilar techniques affect the performance and behaviour of WalkSAT when solving industrial MAXSAT problem instances. Through extensive experiments our results confirm that combining multilevel techniques and Learning Automata with WalkSAT, separately and together, give promising results. We compare these composite algorithms with WalkSAT on selected industrial MAXSAT problems throughout the thesis, and show that all these composite algorithms perform better than WalkSAT

The effect of agile workspace and remote working on experiences of privacy, crowding and satisfaction

Occupant density is an important and basic metric of space use efficiency. It affects user experience of privacy, crowding and satisfaction. The effect of agile working has been two fold. Firstly, offices have an increasing range of workspace settings such as break out space, collaborative space and contemplative space in contrast to the traditional workspace settings of assigned desks and formal meeting rooms. Secondly, office workers have become increasingly mobile as they are able to work from a greater variety of locations both in and out of their main place of work. This study asks whether workers who occupy agile workspaces and those with greater mobility experience privacy differently from workers with more conventional offices and work patterns. The experience of privacy can be considered in terms of retreat from people, control of information flow and control of interactions. Our results show that agile workspaces improve the ability to control information compared with open plan offices. It was also found that highly mobile workers are more sensitive to the negative effects of interacting with people. From this a taxonomy of offices is defined in terms of the features that contribute to the experience of privacy

Evaluation of the Workplace Environment in the UK, and the Impact on Users’ Levels of Stimulation

The purpose of this study is to evaluate a number of recently completed workplaces in the UK. The first aim is to assess the impact of various aspects of the workplace environment on users’ levels of stimulation. The body of previous research undertaken into the workplace environment, identified the aspects to be investigated. Samples of employees from the sixteen businesses were surveyed to determine their perceptions of the workplaces. The results were entered into a regression analysis, and the most significant predictors of perceived stimulation identified. The data also revealed a dramatic reduction in staff arousal levels from mornings to afternoons. Thus, there is a second aim to determine whether changes to significant aspects of the workplace environment during the day can counteract the reduction in users’ stimulation. Two further workplaces were studied to enable changes to be made over a 12-week period. A sample of employees completed questionnaires, and semi-structured interviews revealed the reasons behind the results. It was found that provision of artwork, personal control of temperature and ventilation and regular breaks were the most significant contributions to increasing stimulation after lunch; while user choice of layout, and design and décor of workspaces and break areas, were the most significant aspects at design stage

Surface patterning of polyacrylamide gel using scanning electrochemical cell microscopy (SECCM)

Scanning electrochemical cell microscopy is introduced as a new tool for the synthesis and deposition of polymers on SAM-functionalised Au surfaces. The deposition of poly(N-hydroxyethyl acrylamide) is shown to be enhanced through the electrochemical generation of activating Cu(I)Cl/Me6TREN catalyst. Initiation of the polymerisation reaction is most likely due to in situ generation of reactive oxygen species following oxygen reduction

The effect of accelerated ASR on the mechanical properties and degree of damage of concrete over time - with and without uniaxial compressive stress

The aim of this master thesis is to investigate the effect on mechanical properties and degree of damage in concrete exposed to accelerated Alkali-silica reaction (ASR) and uniaxial com-pressive stress, and test if the Stiffness Damage Test (SDT) still shows promising result as a tool to predict expansion when samples are restrained. It has previously been shown that uni-axial compressive stress inhibits expansion in the compressed direction. In addition, there has been shown a strong correlation between expansion, degree of damage and change in mechan-ical properties in concrete affected by ASR. A new experimental setup was designed to inves-tigate how external compressive stress affects the development of mechanical properties and degree of damage in concrete exposed to accelerated ASR. 18 prisms were cast and placed under different storage conditions with and without uniaxial compressive stress. Cylinders were drilled out parallel and perpendicular to the load direction at different times to study the effect of the restraints. The degree of damage and change in mechanical properties were investigated performing SDT followed by standard compressive strength tests on the cylinders. Elastic modulus, compressive strength and 3 different damage indices; Stiffness damage index (SDI), Plastic deformation index (PDI) and Non-linearity index (NLI), were calculated from the SDT. The indices showed a strong logarithmic correlation with increasing level of expansion and the elastic modulus reduc-tion showed a strong linear correlation with increasing expansion. The restrained prisms exposed to accelerated ASR showed lower level of expansion in restrained direction and similar expansion as the free prisms in unrestrained direc-tion. Free ASR affected prisms showed a small reduction in compressive strength compared to the reference prism. However, when looking at the restrained prisms the result was small and vague. All output parameters except compressive strength points to a lower degree of damage in the restrained prisms. The compressive strength showed weak correlation with expansion and seems to be a poor parameter to use when as-sessing ASR affected concrete. The damage indi-ces, SDI and PDI, showed promising result as tools to assess ASR damaged concrete struc-tures and potentially predict ASR expansion. The NLI showed weak correlation at low expan-sion level, render it less promising. For SDT to be a valid tool to predict expansion, different concrete recipes need to be tested and a thorough description of the test and calculation method needs to be defined

Lifting the fog of oil? Exploring the framing of ambitious local climate politics in an oil city

How can an oil city pursue ambitious local climate politics and policies? Through a critical discussion of the process and debates over the making of an ambitious climate and energy action plan (CAP) in Norway’s oil capital, Stavanger, this paper dissects the paradoxes evident in pursuing local climate policy and politics in a city with high dependence on oil revenue and an identity closely tied to the oil industry. With an analysis of how different actors frame place, scale and knowledge, the paper explores politicians’ arguments, understandings and contestations, revealing how such a plan came into being. The analysis shows a discrepancy in how the actors understand climate change in terms of scale, whether it is an issue suitable for local governance and politics or not, and how they regard the city’s potential role in climate transformation. By mobilizing Stavanger’s past transformation from a poor fishery city into an oil capital to a future as a low-carbon sustainable city, the idea of the city’s transformative capacity became clear. This made space for politicians and parties to change their view on climate change as a matter for local governance and politics, culminating in the passing of a very ambitious CAP.publishedVersio

Breaking silos: can cities break down institutional barriers in climate planning?

Climate and energy transformation has become one of the core issues municipalities must address, and there is a recognition that the local scale is essential if we are to address the fundamental changes needed to face global climate change. However, the nature of climate change as a wicked problem is not compatible with the specialised and sectorised nature of policy-making institutions. Urban and municipal responses to societal problems often involve making a plan. In this article, the potential of climate action plans to break institutional silos is examined. Overcoming institutional obstacles can bring forth new opportunities to shrink the gap between targets and results through knowledge transfer, identification of co-benefits and anchoring of the plan beyond the municipal department in charge. Two cases demonstrating two different approaches to ambitious local climate planning are discussed. Mainstreaming of the planning process can be observed in Trondheim, whilst in Bergen, the process has been highly politically driven. Three factors appear to be important to overcome institutional barriers at the local level: broad processes, political will and institutional entrepreneurs.acceptedVersio

The Emotion Regulation Checklist - Factor Form Invariance and Acquiescence in Norway

The primary purpose of this study was to examine the validity of the Norwegian version of the Emotion Regulation Checklist (ERC; Shields & Cicchetti, 1997). Parent and teacher responses were collected from a community sample of Norwegian children at four timepoints (n= 605-783). Main analyses were confirmatory and exploratory factor analysis, as well as an indicator of acquiescence response style. The results indicated that the latent structure of the Norwegian version of the ERC differed from the two-factor structure suggested by the original authors. Post-hoc analysis failed to identify meaningful model-alterations, and explorative analysis did not succeed to reveal alternative solutions with acceptable fit and interpretability. In addition, both scales in the original two-factor solution seemed to be contaminated by parents’ acquiescence. As so, the validity of the Norwegian version of the ERC was not supported, and its use in Norway should be carefully considered due to interpretation difficulties and validity issues

Workplace productivity and office type: an evaluation of office occupier differences based on age and gender

Purpose Open plan office environments are considered to offer workplace productivity benefits because of the opportunities that they create for interaction and knowledge exchange, but more recent research has highlighted noise, distraction and loss of privacy as significant productivity penalties with this office layout. This study aims to investigate if the purported productivity benefits of open plan outweigh the potential productivity penalties. Design/methodology/approach Previous research suggests that office environments are experienced differently according to the gender and age of the occupier across both open-plan and enclosed configurations. Empirical research undertaken with office occupiers in the Middle East (N=220) led to evaluations to establish the impact different offices had on perceived productivity. Factor analysis was used to establish five underlying components of office productivity. The five factors are subsequently used as the basis for comparison between office occupiers based on age, gender and office type. Findings This research shows that benefits and penalties to workplace productivity are experienced equally across open-plan and enclosed office environments. The greatest impact on perceived workplace productivity however was availability of a variety of physical layouts, control over interaction and the 'downtime' offered by social interaction points. Male occupiers and those from younger generations were also found to consider the office environment to have more of a negative impact on their perceived workplace productivity compared to female and older occupiers. Originality/value The originality of this paper is that it develops the concept of profiling office occupiers with the aim of better matching office provision. This paper aims to establish different occupier profiles based on age, gender and office type. Data analysis techniques such as factor analysis and t-test analysis identify the need for different spaces so that occupiers can choose the most appropriate space to best undertake a particular work task. In addition, it emphasises the value that occupiers place on ‘downtime’ leading to the need for appropriate social space