| 1391. |
- Sundqvist, Erik, 1985-
(författare)
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Towards systematic improvement work in project-based organizations : An efficiency and effectiveness perspective
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Project-based organizations (PBOs) have adopted projects as a primary tool for carrying out most of their operations. By doing so, the PBO operates mainly on two organizational levels, the project level and the organizational level. For these organizations, improving project management (PM) performance is central for the survival of the organization, since PM is considered both a strategic competence and a source of competitive advantage for delivering customer value. For PBOs, prioritizing efficiency has often been described as a short-term focus meeting time and budget targets. The need to shift focus toward value creation in PM is suggested to be of importance to succeed in delivering value to customers. Project performance, and the separate but interlinked concept of project success, can be described using the two concepts of efficiency—doing things right—and effectiveness—doing the right things. However, although commonly used within the field of quality management, the application of these two concepts in the PM literature and practice has proven to be unclear which has implications on organizational improvement.It is through the two concepts, efficiency and effectiveness, that systematic improvement work in PBOs can be understood. This thesis addresses the need for influences from other research fields, by approaching improvement work in PBOs from a quality management perspective. More specifically, the purpose is to advance our understanding of how PBOs can work systematically toward improvements, from an efficiency and effectiveness perspective. This is done by exploring challenges related to improvement work in a PBO operating as a subsidiary to the Swedish minerals group LKAB. In order to do this case study research has been used, including a combination of data collection methods: including semi-structured interviews, participant observations, and document analysis. Case study findings have continually been compared to theory in order to reach conclusions.The findings indicate that an organizational-level improvement process is missing, and that PBOs need to link such a process to project-level processes, in order to work toward improvements. Applying an efficiency and effectiveness perspective further clarifies the division of practice and responsibility between PBO and the client. Further, it is suggested that the role of the project manager as an improvement agent in PBOs should be formalized and clarified, in order to support learning and organizational-level improvement. Finally, the need to clarify and manage what constitutes value and value creation among stakeholders in projects is emphasized, in order to support both efficiency and effectiveness in project work.The thesis contributes to the literature by discussing the prerequisites for PBOs to work toward improvements, and by approaching project management from a quality management perspective. From a managerial perspective the thesis emphasizes the importance of clarifying responsibilities regarding project value creation, as current practice seem to promote a separation of responsibility, in which the PBO is responsible for aspects of efficiency, and the customer is responsible for aspects of effectiveness.
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| 1392. |
- Sundqvist, Jesper
(författare)
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Aspects of Heat Flow in Laser Processing of Metals
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since the laser was invented in 1960, its use in manufacturing industry has been growing rapidly. Laser processing of metals is based on the flow of heat that is generated by the absorbed laser beam. One outstanding aspect of laser beams is high precision along with high controllability of energy transfer, which includes creative techniques of shaping the beam and in turn the process. The thesis presents six Papers A-F on different metal processing techniques, namely welding, hardening and cutting, the latter combined with additive manufacturing. For each respective technique it was studied how desired properties can be optimized by controlled use of the laser beam and in turn of the temperature field. Addressing their different complexity of the heat transfer, various theoretical and experimental analysis methods were applied.Laser beam welding is usually conducted with standard beam shapes, i.e. Gaussian or top-hat like, which is not always optimal for the process. Identification of an optimised weld pool shape or temperature cycle could increase the quality of welded products or even enable new applications. Papers A and B aim to increase the knowledge for non-standard beam shapes, particularly for single-pulse conduction mode welding. Paper A presents an investigation on an industrial application where a C-shaped weld joint is desired. The sensitivity to and optimization of different C-shaped beam irradiation profiles is discussed. The analysis is mainly carried out by applying Finite Element Analysis, FEA, to calculate the heat conduction contributions, showing unexpected sensitivity in certain regimes. Paper B presents a semi-analytical model for fast calculation of the temperature field from different beam profiles. Examples include multi-spots or the misalignment sensitivity of Diffractive Optical Elements.In Paper C, for laser hardening of 11% Cr ferritic stainless steel the temperature field was studied to enable hardening. It was shown that single-track hardening without sensitisation could be achieved but overlapping tracks had a continuous network of ditched grain boundaries and is thereby at risk for sensitisation. The sensitised area is caused by a reheating cycle.The same mechanism for the same material was studied in Paper D when applying a recently developed drop deposition technique, where additive manufacturing is fed by laser cutting. The same reheating isotherm becomes critical, but here sensitisation tests show a discontinuous network of ditched grain boundaries in the added material. The solid heat-affected zone on the other hand has a continuous network of ditched grain boundaries, which implies a sensitisation risk. The continuous network is however not in contact with the surface. The tested parameters is thus not at risk for intergranular corrosion through sensitisation.For friction stir welding of dissimilar metals, Ti-6Al-4V with AISI 304L stainless steel, Paper E, the influence of a laser-induced preheating temperature field on the tool forces was investigated through numerical simulation. By suitable application of laser preheating, the forces acting on the tool can be substantially lowered, in a robust manner.The temperature field from seam welding induces a residual stress field. In Paper F, for continuous wave laser keyhole welding of high strength steel butt joints, a method is presented to identify the residual stress behaviour of laser welded sheets by measurement of the fatigue crack growth rate during testing, by deriving the crack acceleration. The analysis was confirmed by hole drilling tests and by FEA.The knowledge and methods of the above different experimental and theoretical studies complement each other. They contribute to further optimize certain aspects through laser-induced temperature fields, for different manufacturing techniques.
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| 1393. |
- Sundqvist, Thomas
(författare)
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Power generation choice in the presence of environmental externalities
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation consists of an introductory part and six self-contained papers, all related to the issue of power generation choice in the presence of environmental externalities. Paper 1 provides a critical survey of a large number of electricity externality studies carried out during the last decades, and discusses a number of conceptual, policy-related and, in some cases, unresolved questions in the economic valuation of electricity externalities. These include: (a) the definition of externalities; (b) the choices of scope, relevant parameter input assumptions, and methodology; (c) the role of “green” consumer demand in replacing external cost assessments; and (d) the behavioral assumptions and ethical principles underlying external cost valuation. Paper 2 focuses on explaining the variability of results among the external cost studies carried out so far by providing an econometric analysis of a large sample of externality studies. Most importantly, the paper concludes that an important explanation for the reported disparities can be attributed to the overall methodological choice employed. Paper 3 explores some of the ethical limits of environmental valuation, and analyzes what the implications are of these limits for the social choice between different power sources. The main thesis of the paper is that the scope of electricity externalities where non-market valuation can be applied from an ethical point of view is likely to be narrower than commonly assumed. Papers 4 and 5 use the choice experiment method to estimate how the environmental impacts arising from hydroelectric production are perceived and valued by Swedish house-owning households and non-residential consumers. The basis of the choice exercise is taken in the criteria set up by the Swedish Society for Nature Conservation under which existing hydropower in Sweden can be labeled as “green” electricity. Data are gathered using mail- out surveys to 1000 households and 845 private and public enterprises, respectively. In general the results indicate that environmental investments in the hydro sector should, according to the respondents, primarily be directed towards lowering the negative impacts on fish life in the river affected by the hydroelectric development. Finally, paper 6 examines cost- reducing innovations for wind turbine farms in Denmark, Germany, and the United Kingdom. An econometric analysis using an expanded version of the two- factor learning curve concept, in which investment cost reductions are explained by cumulative capacity and the R&D based knowledge stock, is performed. The results show that both these factors have had a significant impact on cost reductions in the wind power sector.
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| 1394. |
- Sundström, Joel, 1988-
(författare)
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Studies of Transient and Pulsating flows with application to Hydropower
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The rotational motion of a hydraulic turbine runner makes pulsating flows ubiquitous in different locations of the machine. The cyclic loading thus induced may generate large pressure forces acting periodically on both stationary and rotating parts. In addition to the presence of pulsating flows in a turbine runner, transient flows are encountered at an increasingly higher rate due to the continual installation of intermittent sources of renewable energy, such as wind and solar power. To mitigate the imbalance that these unpredictable sources induce on the frequency of the electrical grid, hydropower turbines are enforced to regulate their power production, and consequently flow rate, thus leaving them to operate under transient conditions. In terms of wear and fatigue, a startup or shutdown of a hydraulic turbine corresponds to 10-20 hours of steady state operation at the design point. Transient operation of a hydraulic machine can, however, also be used in favour for measuring the discharge through the turbine using the pressure-time method. A better understanding of pulsating and transient flows thus has the potential both to mitigate problems associated with them, and to increase the accuracy with which the turbine flow rate can be measured; two great merits for the hydropower community. In light of this observation, the following work constitutes a fundamental investigation of transient and pulsating flows performed in a straight pipe.Studies have been performed experimentally using particle image velocimetry, hot-film anemometry, laser Doppler velocimetry and pressure sensors.A chief finding is that the time-development of the wall shear stress and near-wall turbulence fields exhibit significant similarity between transient and pulsating flows, despite the different conditions of the mean flow. Whereas the former is initiated from a statistically steady state, the latter is constantly subjected to a time-varying forcing. Both types of unsteady flows have previously been investigated in detail; however, any potential similarity between them has, largely, been unexplored. An important implication of this finding, then, is that knowledge acquired in one type of unsteady flow can be used, if not interchangeably, at least as a guidance for the expected behaviour in the other type of flow. An example is the development of unsteady turbulence models. Another important finding is that the frictional losses arising during the late stage of a pressure-time flow rate measurement can be accurately modelled using an analytical laminar formulation of the wall shear stress, despite the bulk of the flow being turbulent. The formulation of the wall shear stress has potential to be further improved by incorporating a damping-function.
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| 1395. |
- Sundström, Mikael
(författare)
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Time and space efficient algorithms for packet classification and forwarding
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Internet consists of a mesh of routers (nodes) connected by links (edges) and the traffic through the Internet is divided into flows where each flow is an ordered sequence of packets, or datagrams. Each packet consists of a header and a piece of data, also referred to as payload. The header contains information about source and destination of the packet as well as some additional information. The primary function of an Internet router is to inspect the destination address of a packet, determine in which direction, i.e. on which link, to forward the packet on its next step towards its destination and then to forward the packet. This is called forwarding and is one of the problems considered in this thesis. Forwarding is essentially a data structuring problem where a local view of the Internet surrounding the router is represented in the form of a forwarding table, where the destination address can be looked up to determine the forwarding direction. In this thesis we develop a number of forwarding table data structures with different characteristics, both for supporting the current Internet Protocol IP version 4, which uses 32-bit addressing, as well as tomorrows IP version 6 featuring 128-bit addresses. The secondary function is the ability to determine whether to forward a packet or not based on the information from one or more header fields. While the entries stored in a forwarding table are 1-dimensional intervals, the entries used for packet classification are D-dimensional, where D is typically larger than or equal to 5. As a result, packet classification requires some degree of brute force, either in terms of parallel processing or huge amount of memory to achieve guaranteed performance. We have developed efficient algorithms for reducing the number of bits involved in the actual D-dimensional classification. These algorithms can be used to improve performance of both brute force hardware classifiers and heuristic software based classifiers. We first work on a purely theoretical problem called implicit selection where the solution as such does not have any impact whatsoever on forwarding and packet classification. However, in the process of solving the implicit selection problem, we have worked with numerous in-place techniques that becomes extremely useful when dealing with some aspects of packet classification and forwarding later on. It is interesting to see how techniques for achieving good performance in Asymptopia can be used also in the real world. The next step is to develop a data structure called hybrid tree where the keys are stored with minimal storage overhead and the lookup cost is independent of the number of keys in a non-trivial way. We also show how to engineer both static 128-bit single field classification without storage overhead as well as dynamic 128-bit classification with roughly 40% storage overhead that support reasonably fast update operations. Next we deal with compression state lookup for IPv6 header compression, using a dynamic move-to-root Patricia tree which adapts to the traffic pattern in an on-line fashion, followed by classification of fragmented packets, using a highly dynamic dictionary data structure featuring automated garbage collection. This is followed by two forwarding algorithms with completely different properties. The first algorithm is called XTC and supports fast lookups and good average compression but not incremental updates whereas the second algorithm is based on hybrid trees and features fast lookups and updates as well as good table compression. Finally, we present a packet classification algorithm which reduces both silicon area and power consumption for a hardware implementation. Our approach is to use hybrid trees to compress the addresses to reduce the total number of bits involved in final parallel processing. For IPv6 multifield classification, we can reduce the total number of transistors by 50% and the power consumption by over 80% compared to existing technologies for interval matching in hardware.
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| 1396. |
- Sundström, Nils
(författare)
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Improving snow water equivalent estimates with ground penetrating radar by measuring on multiple channels
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Snow water equivalent (SWE) of a snowpack is often measured along well-chosen transects representative of an area of interest, such as a drainage basin, to capture spatial distribution of SWE, which is of great interest for many applications. For example, it is a useful input to the new generation of hydrological models used for snow melt run-off predictions. A time-effective method to perform such measurements is to conduct them along one or several transects using a ground penetrating radar (GPR) operated from e.g. a snowmobile. Traditionally, a single-channel radar system has been used to estimate SWE from the radar wave two-way travel time via a linear formula, which can be calibrated for a particular snowpack with one or several manual measurements of snow density; this method typically relies on the assumption of a dry snowpack. However, if an unknown amount of liquid water is present in the snow, or if the snow density or the liquid water content varies substantially along the transect, SWE estimates are likely to be inaccurate.A different approach is to use a multi-channel GPR system with an array of antennas that makes it possible to simultaneously measure two-way travel time of several radar pulses that form a common mid-point (CMP) gather. Then the snow depth and the radar wave propagation velocity can be determined at each point with the CMP method under the assumption of a single-layer snowpack with parallel snow and ground surfaces. With liquid water content known or assumed to be zero, the snow density can be estimated from the propagation velocity via an empirical formula for mixtures, thus solving the problem of spatial variation in snow density. Finally, SWE is calculated from the snow depth and density. However, the CMP method is known to be sensitive to measurement errors in two-way travel time and to violations of its assumptions; and for a wet snowpack, the need to know the liquid water content at each measurement point to accurately estimate snow density presents a problem if the liquid water content varies along the transect.In this thesis, two methods that improve SWE estimates obtained with GPR are presented, both of which rely on measuring on multiple channels to obtain a CMP gather at each measurement point. The first method mitigates the impact of errors in CMP calculations on density estimates by establishing a depth-to-density function from the CMP data for all measurement points along a transect. This function, specific for each transect, is then used to determine snow density from snow depth. The second method (the PDA method) improves SWE estimates of wet snowpacks by determining liquid water content at each measurement point from path-dependent attenuation of two radar signals in the CMP gather. Both methods have been tested in field experiments and the sensitivity of the PDA method to built-in assumptions and measurement errors has been investigated in simulations.The field experiment conducted to test the first method has demonstrated that by applying a depth-to-density function, the accuracy of SWE estimates for a dry snowpack can be improved substantially. For the transect in the experiment, snow density and SWE estimated directly with the CMP method were overestimated by 34% and 36% on average; and when a depth-to-density function was used, snow density was underestimated by 2% and SWE was overestimated by less than 1%. The error was determined by comparison with manual measurements.In the field experiment conducted to test the PDA method, for a snowpack with the mean liquid water content of about 5 vol.%, the mean error in SWE was 16%, compared to 34% and 31% for two reference methods that both assumed liquid water content to be zero. Separately, the performed simulations suggest that the PDA method is very sensitive to measurement errors when liquid water content is close to zero; in such cases, one of the methods that assume dry snow should be used instead of the PDA method.
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| 1397. |
- Surakka, Jouni
(författare)
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Dermal exposure to UV-radiation and UV-curable acrylate coatings in the wood working industry
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work with UV radiation curable coatings (UV-coatings), increasingly used in the wood working industry, involves risks from skin exposure to hazardous UV-radiation and to harmful compounds in UV-coatings. The coatings contain acrylates that are known skin irritants and sensitizers. Intensity and spectral emission of stray light from the curing lamps (UV-radiation 250-400 nm) was measured under production conditions. Maximal permissible exposure times were calculated from doses after biological weighting. Radiation in biologically hazardous wavelengths from poorly shielded UV curing units involved a risk of overexposure in a matter of seconds to minutes. An efficient, accurate, and economical method was developed for surface sampling and quantitative gas chromatographic determination of tripropylene glycol diacrylate (TPGDA), a major constituent of UV-lacquers. This method was employed in the workplaces for measuring (1) skin exposure, (2) surface contamination to UV-coatings and (3) protection efficiency of working clothes against skin contamination from UV-coatings. Skin exposure was measured at standardized sites, 3 to 4 times per work shift and at two separate workdays. Skin contamination was found on 16 of 23 workers at 6 of the 7 workplaces, and from 36 (5.4%) of the 664 samples taken from the skin of the workers. Surface contamination was widely spread at workplaces and found in 153 out of 196 samples (78%). T-shirt fabric, commonly used by the workers provided marginal protection, whereas thicker working cloth fabrics provided acceptable protection against UV-coating. The tape sampling method provides a powerful tool to measure skin and surface contamination, which is a common but previously unstudied problem. Skin exposure to acrylates can be minimised by eliminating the use of hazardous coatings, by education and by improving control measures.
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| 1398. |
- Sutaria, Jil
(författare)
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On the supraharmonics in single-phase and three-phase installations
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Society has increasingly started depending on the continuity of internet services, the interruption can be crucial for vital societal functions. It is therefore important to maintain continuous and reliable operations of e.g., installations housing sensitive IT (Information Technology) loads. The establishment of a data center attracts huge investments, thereby boosting the economy. The electrical load within the data center is more structured with a similar type of load, i.e., power supplies supplying the servers connected repetitively. They also use power-conditioning equipment such as an uninterruptible power supply (UPS), which ensures uninterrupted power to the servers. The power supplies use switching techniques to modulate and condition the power supplied to the IT load. The switching residues from the power supplies are often in the frequency range from 2 kHz to 150 kHz, known as supraharmonics. The switching frequency of power electronic converters and power line communication are identified as the main contributors to supraharmonics. The increase in the number of power electronic converters in the power system has sparked interest in supraharmonics. Limited standards are available on the magnitude of supraharmonics allowed in the system. For installations that house multiple power converters, prior knowledge about the propagation and consequences of the supraharmonics can be an advantage in increasing their reliability. This work is focused on supraharmonics within data centers, but the results of the study can be applied to other installations.The data centers are usually three-phase installations where single-phase devices, i.e., servers are distributed over three phases. To understand the holistic view of the system, it is important to understand the spread of supraharmonics in phase, neutral, and protective earth conductors. A perspective on the behaviour of supraharmonics in three-phase installation is presented in this work. The focal point of the work is the summation of supraharmonics in the neutral conductor and conductor crosstalk. The behaviour of the device connected in single-phase installation and when the same devices are spread over three phases may differ depending on the design of the installation. Since the focus is on a greater number of devices, analysis for the change in the magnitude of supraharmonics in a neutral conductor with the change in the number of devices is also undertaken. The IT workload in a data center changes continuously, thus a constant unbalance in the electrical load between the three phases can exist. The thesis aims to understand the factors influencing the change in supraharmonic magnitude and propagation in phase and neutral conductors according to a balanced and unbalanced voltage supply and loading conditions. The presence of a supraharmonic emitting load in one phase can cause interference on the adjacent phase due to conductor crosstalk. Crosstalk leads to the propagation of supraharmonics between the phases. The work focuses on the parameters influencing the crosstalk phenomena for supraharmonics. Among the parameters studied, the type of cable used in an installation and the cable length is dominating. The measurement of supraharmonic emission from the device connected as single-phase and connected as three-phase would differ because of crosstalk.A large number of servers in data centers connected close by may lead to an increased leakage current. The composite leakage current can comprise subharmonics, harmonics, and supraharmonics. This can cause unwanted tripping of the residual current device (RCD), which is installed for human protection. The work aims to understand the impact of the composite residual current on the operation of the residual current devices.The main contributions of this work are summarized as:• A sensitivity analysis is presented based on the parameters impacting the propagation of supraharmonics for different operating modes of a UPS.• A characterization of supraharmonics emission from different devices according to their time and frequency varying behaviour.• A mathematical model to predict the change in the supraharmonic emission in the neutral conductor.• An increased understanding of the behaviour of supraharmonics for constant powerloads under voltage reduction conditions in three-phase installations.• Introduction and definition of the terms induced primary emission and induced secondary emission to explain conductor crosstalk for supraharmonic emission.• A mathematical model to show the factors influencing the magnitude of induced primary emission and induced secondary emission.• The frequency response of RCDs of type AC, A, B, and F under residual currents comprising pure tones and composite currents is presented by measurements andmodeling.
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| 1399. |
- Svanberg, J. Magnus
(författare)
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Predictions of manufacturing induced shape distortions : high performance thermoset composites
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High performance composites usually consist of continuous fibres and a thermoset matrix. A well-known example is carbon fibre epoxy composites. When this kind of material is cured residual stresses and/or shape distortions are produced owing to thermally and chemically induced volumetric strains. The cure means the manufacturing step where the thermoset matrix is transformed from a liquid to a solid material. It is a quite complex thermal- chemical- mechanical process that in addition to volumetric strains, involves heat generation and dramatic changes in mechanical properties. For manufacturing of parts with high shape tolerances, such as aircraft components, the geometry of the mould is compensated to accommodate for shape distortions. Today this is made based on thumb rules and experience followed by trials. This is time consuming and expensive. Development of a tool for prediction of shape distortions and residual stresses is therefore an important step towards more optimised manufacturing of composites. The present thesis, consisting of five papers, describes the development and validation of a simulation tool for prediction of shape distortion and residual stresses. In the first paper a typical material and manufacturing process for high performance composites was used to experimentally investigate the effects from the cure temperature on spring-in of angle sections. The experimental results were interpreted in terms of mechanisms responsible for shape distortions. Based on the observations, a process model including a new mechanical constitutive model for predictions of residual stresses and shape distortions was proposed and implemented in a general purpose FE-program, as presented in the second paper. In the third paper, the model was validated by comparing spring-in predictions with the experimental results of the first paper complemented by same new experiments. The third paper also embraces a numerical investigation of the effect from the mechanical boundary conditions during cure. So far (in the three first papers), the curing conditions were kept isothermal. When a thick component is cured, the conditions are no longer isothermal owing to heat generated by the exothermal cure reaction. Hence, in the fourth paper the process model was validated against experimental results for a non-isothermally cured component. Finally, in the last paper shape distortions of a complex aircraft component was studied. This was made to both get further validation of the process model as well as investigate the feasibility to simulate large parts of complex shape.
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| 1400. |
- Svanbro, Angelica
(författare)
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Speckle interferometry and correlation applied to large-displacement fields
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A common problem in experimental mechanics is that when a sample is studied in e.g. a tensile test machine, the sample is often exposed to rigid body motions at the same time as small deformations occur. These two movements, the rigid body motion and the deformation, are often talked about as displacement fields. The sought deformation field is often in the micrometer range while the rigid body motions often are of millimetre or centimetre size. Therefore, it is often a problem to resolve the deformation field since it is drowned by the larger movement of the object. The displacement field can be measured with methods like speckle correlation, but the results might be of too poor accuracy to resolve the deformation field. Interferometric methods on the other hand might measure the deformation field but the rigid body motion makes the fringes disappear. In this thesis two methods are presented that makes it possible to master such measuring situations: a combination of speckle interferometry/speckle correlation and a method where the reference image is updated frequently during the experiment. Both theory and experiments are presented. For the combined speckle interferometry/speckle correlation, it is shown that the information necessary to apply the speckle correlation method is already available in interferometric recordings. With only minor changes in the calculation procedures, the speckle motion in the recordings can be determined. Interference fringes, which have disappeared due to large speckle motions, are retrieved by digital compensation for this motion. The speckle correlation technique gives the motion of the whole surface of the object so different areas of the object can move different amounts and in different directions and it is still possible to retrieve the fringes describing the deformation field. Updating the reference image during the experiment is another method used. As soon as the specimen has moved 1/10 of a speckle the reference image is updated in order to avoid speckle decorrelation. In this way the total movement of the surface is added up during the experiment and a phase map describing the displacement of the object is achieved. Finally, the magnitude of the shear in shearography is measured using speckle correlation. This allows quantitative measurements of the spatial derivative of the deformation field in shearography.
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