Debonding along the fixed anchor length of a ground anchorage

Peer reviewedPostprin

Strategy-focused architecture investment decisions

The thesis considers how a systematic approach for evaluating architecture investments can lead to decisions that are driven by business preferences rather than by personal incentives. A decision to invest in software-architecture requires systematic evaluation of the trade-off between strategic long-term benefits of architecture on the business and short term investment. It typically is a decision that is difficult to explain and quantify. In this sense, it is not surprising that such a decision is often driven by personal incentives or strong leadership of deciders, architects and managers, leading to suboptimal decision-making process in the organization. This PhD thesis proposes a way in which to support the decision to invest in architecture by linking the architecture improvements to the business strategy and taking into consideration the human aspects. We follow the iterative study design process including several real-life case studies, multiple interviews, and an experiment. In the first case study, we investigate how practitioners make a decision on architecture investment with a focus on how the decision process can be improved in industrial practice. To support the decision process in an objective way, we propose to use arguments based on real options theory. The evaluation by practitioners disclosed that including such economics of architecture is necessary but not sufficient for decision making. To better understand the information needs for decision making we conducted field interviews on the kinds of information that architects and managers need. In a subsequent experiment we tested whether which kind of information is actually used in decision making. As expected, the professionals tend to use just a few information types for decision making. However, our results suggest that additional quantified information was used by participants with longer development experience and under time pressure. Based upon the experimental findings we propose a concept to quantify the customer value of architecture. Despite the positive evaluation, the practitioners asked for further improvements to translate the architecture changes directly to the economic value. Ultimately, based on the findings from the preceding studies we propose a comprehensive approach to support objective architecture decision making; we label it Strategy-focused Architecture (StArch). Adopting strategic management tools, strategy map and balanced scorecards, we provide step-by-step guidance to assess the economic benefits of architecture improvements aligned with the strategic business objectives

Experimental observation of ultrashort laser pulse effects on the autoionization dynamics of argon atoms

Within this work, electron dynamics inside argon atoms are observed by probing the autoionizing states of argon atoms, so-called window resonances, with both attosecond XUV and timed-delayed few-cycle femtosecond NIR laser pulses, using attosecond transient absorption spectroscopy. The window resonances in the energy region of 25 - 29.3 eV are first excited with the XUV pulse and then dressed by the NIR laser, where the natural decay process of the states is greatly affected by the strong-field of the NIR pulse. Preliminary results of the measurement are presented in this work, with a hypothetical description of some of the effects that are present. A comparison has been made with the experimental results from a paper publishing measurements of autoionizing states with attosecond transient absorption spectroscopy for the first time, where the same resonances were probed. The comparison is only partly possible due to different experimental parameters and conditions, where more pronounced and new effects have been observed in the here performed measurement

How well can you know the edge of a quantum pyramid?

We consider a symmetric quantum communication scenario in which the signal states are edges of a quantum pyramid of arbitrary dimension and arbitrary shape, and all edge states are transmitted with the same probability. The receiver could employ different decoding strategies: he could minimize the error probability, or discriminate without ambiguity, or extract the accessible information. We state the optimal measurement scheme for each strategy. For large parameter ranges, the standard square-root measurement does not extract the information optimally.Comment: 13 pages, 5 figures, 1 tabl

Singlet states and the estimation of eigenstates and eigenvalues of an unknown Controlled-U gate

We consider several problems that involve finding the eigenvalues and generating the eigenstates of unknown unitary gates. We first examine Controlled-U gates that act on qubits, and assume that we know the eigenvalues. It is then shown how to use singlet states to produce qubits in the eigenstates of the gate. We then remove the assumption that we know the eigenvalues and show how to both find the eigenvalues and produce qubits in the eigenstates. Finally, we look at the case where the unitary operator acts on qutrits and has eigenvalues of 1 and -1, where the eigenvalue 1 is doubly degenerate. The eigenstates are unknown. We are able to use a singlet state to produce a qutrit in the eigenstate corresponding to the -1 eigenvalue.Comment: Latex, 10 pages, no figure

The Effect of COVID-19 on Independent African Churches (IACs) in Johannesburg, South Africa

This paper explores the effect of the COVID-19 pandemic on the religious tourism activities of the four most prominent Independent Apostolic Churches (IAC) operating in Johannesburg, South Africa. This is an interpretive qualitative research study based on data from 15 telephone-based semi-structured interviews with congregants and church leaders of the Zion Christian Church, Zimbabwe (ZCC Mutendi), The Apostolic Church of Johane Marange, The Apostolic Church of Johane Masowe and Apostolic Faith Church, Mugodhi. Thematic content analysis was used for data analysis. The COVID-19 pandemic has negatively impacted the religious tourism activities of all four IACs in the study as they accepted and implemented various aspects of the lockdown regulations. The cancellation of their main annual events and weekly and monthly activities combined with a considerable reduction in contribution from their members resulted in churches’ inability to finance their main activities, i.e. their healing camps. It is evident that the ripple effects of reduced IAC activities in and around Johannesburg has negatively affected the city’s income from churches’ religious tourism activities. This is the first study to explore the activities of IACs in Johannesburg (and Africa) before and during the pandemic, pointing to churches’ significant contribution to religious tourism in the city

Optimal Conclusive Discrimination of Two Non-orthogonal Pure Product Multipartite States Locally

We consider one copy of a quantum system prepared in one of two non-orthogonal pure product states of multipartite distributed among separated parties. We show that there exist protocols which obtain optimal probability in the sense of conclusive discrimination by means of local operations and classical communications(LOCC) as good as by global operations. Also, we show a protocol which minimezes the average number of local operations. Our result implies that two product pure multipartite states might not have the non-local property though more than two can have.Comment: revtex, 3 pages, no figur

Reduction Theorems for Optimal Unambiguous State Discrimination of Density Matrices

We present reduction theorems for the problem of optimal unambiguous state discrimination (USD) of two general density matrices. We show that this problem can be reduced to that of two density matrices that have the same rank $n$ and are described in a Hilbert space of dimensions $2n$. We also show how to use the reduction theorems to discriminate unambiguously between N mixed states (N \ge 2).Comment: 6 pages, 1 figur

Maximal Entanglement, Collective Coordinates and Tracking the King

Maximal entangled states (MES) provide a basis to two d-dimensional particles Hilbert space, d=prime $\ne 2$. The MES forming this basis are product states in the collective, center of mass and relative, coordinates. These states are associated (underpinned) with lines of finite geometry whose constituent points are associated with product states carrying Mutual Unbiased Bases (MUB) labels. This representation is shown to be convenient for the study of the Mean King Problem and a variant thereof, termed Tracking the King which proves to be a novel quantum communication channel. The main topics, notions used are reviewed in an attempt to have the paper self contained.Comment: 8. arXiv admin note: substantial text overlap with arXiv:1206.3884, arXiv:1206.035