| 1. |
- Bernhard, Irene
(författare)
-
E-government and e-governance : Swedish case studies with focus on the local level
- 2013
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The concepts of e-government and e-governance are used interchangeably in most research and there is no single definition of these terms. The objective of this licentiate thesis is to provide a deeper understanding of these concepts through empirical studies in a Swedish context. Further, it aims to analyse whether – and if so in what way – the implementation of local contact centres (CC) affect conditions for local planning. This is reported in three articles. In this thesis e-government is defined to as the use of tools and systems by governmental bodies made possible by ICT that affect the organization of public administration. E-governance is defined as the ICT-based networks of services and administration in New Public Management settings including both public and private actors. Case study methodology is used as research method, including interviews, focus group studies, document studies, and some participatory observations. The analysis is partly built on an inductive methodological approach, since this is a new, emerging field of innovative policy and practice. Based on a theoretical discussion of New Public Management in the digital era, findings show that there is a difference between the concepts of e-government and e-governance from the perspective of e-administration and e-services and that the terms should not be used interchangeably. The study indicates that there are examples of implementation that are referred to the e-governance setting. Further the study indicates that local municipal contact centres may be referred to not only as an implementation of e-government but as a combination of e-governance and e-government. The findings indicate that there is a potential for positive impact on the conditions for local planning through the implementation of municipal contact centres.
|
|
| 2. |
- Repo, Jari
(författare)
-
Condition monitoring of machine tools and machining processes using internal sensor signals
- 2010
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Condition monitoring of critical machine tool components and machining processes is a key factor to increase the availability of the machine tool and achieving a more robust machining process. Failures in the machining process and machine tool components may also have negative effects on the final produced part. Instabilities in machining processes also shortens the life time of the cutting edges and machine tool. The condition monitoring system may utilise information from several sources to facilitate the detection of instabilities in the machining process. To avoid additional complexity to the machining system the use of internal sensors is considered. The focus in this thesis has been to investigate if information related to the machining process can be extracted directly from the internal sensors of the machine tool. The main contibutions of this work is a further understanding of the direct response from both linear and angular position encoders due the variations in the machining process. The analysis of the response from unbalance testing of turn tables and two types of milling processes, i.e. disc-milling and slot-milling, is presented. It is shown that operational frequencies, such as cutter frequency and tooth-passing frequency, can be extracted from both active and inactive machine axes, but the response from an active machine axis involves a more complex analysis. Various methods for the analysis of the responses in time domain, frequency domain and phase space are presented.
|
|
| 3. |
- Wanner, Bertil
(författare)
-
Strategies for Reducing Vibrations during Milling of Thin-walled Components
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Factors such as environmental requirements and fuel efficiency have pushed aerospace industry to develop reduced-weight engine designs and thereby light-weight and thin-walled components. As component wall thickness gets thinner and the mechanical structures weaker, the structure becomes more sensitive for vibrations during milling operations. Demands on cost efficiency increase and new ways of improving milling operations must follow.Historically, there have been two “schools” explaining vibrations in milling. One states that the entry angle in which the cutting insert hits the work piece is of greater importance than the exit angle. The other states that the way the cutter leaves the work piece is of greater importance than the cutter entry. In an effort to shed some light over this issue, a substantial amount of experiments were conducted. Evaluations were carried out using different tools, different tool-to-workpiece offset positions, and varying workpiece wall overhang. The resultant force, the force components, and system vibrations have been analyzed.The first part of this work shows the differences in force behavior for three tool-to-workpiece geometries while varying the wall overhang of the workpiece. The second part studies the force behavior during the exit phase for five different tool-to-workpiece offset positions while the overhang is held constant. The workpiece alloy throughout this work is Inconel 718.As a result of the project a spread sheet milling stability prediction model is developed and presented. It is based on available research in chatter theory and predicts the stability for a given set of variable input parameters.
|
|
