Nearshore populations have been depleted and some have not yet recovered. Therefore, theoretical studies focus on improving fisheries management and designing marine protected areas (MPAs). Depleted populations may be undergoing an Allee effect, i.e. a decrease in fitness at low densities. Here, I constructed a marine metapopulation model that included pre- and post-dispersal Allee effects using a network theory approach. Networks represent metapopulations as groups of nodes connected by dispersal paths. With this model I answered four questions: What is the role of Allee effects on habitat occupancy? Are MPAs effective in recovering exploited populations? What is the importance of larval dispersal patterns in preventing local extinctions due to exploitation and Allee effects? Can exploitation fragment nearshore metapopulations? When weak Allee effects are included, habitat occupancy drops as larval retention decreases because more larvae are lost to unsuitable habitat. With strong Allee effects habitat occupancy also drops at high larval retention because more larvae are needed to overcome the Allee effect. Post-dispersal Allee effects seem more detrimental for nearshore metapopulations. MPA effectiveness seems also lower in a post-dispersal Allee effect scenario. In overexploited systems, local populations that go extinct are also less likely to recover even after protecting the whole coastline. In exploited nearshore metapopulations with Allee effects, local occupancy or the recovery of local populations depends not only on larval inflow from neighbor populations, but also on larval inflow for these neighbors. Nearshore metapopulations with intense fishing mortality and Allee effects may also suffer a decrease in dispersal strength and fragmentation. Population fragmentation occurs when large populations are split into smaller groups. A tool for detecting partitioning in a network is modularity. The modularity analysis performed for red abalone in the Southern California Bight showed that exploitation increases partitioning through time before the entire metapopulation collapses. These findings call for research effort in estimating the strength of potential Allee effects to prevent stock collapse and assess MPA effectiveness, evaluating the predictability of local occupancy by centrality metrics to help identify important sites for conservation, and using modularity analysis to quantify the health of exploited metapopulations to prevent their collapse. / text

Analysing ecological communities as complex networks of interactions has become an important tool for ecologists. Understanding how these networks change through time, over landscapes, or in response to disturbances is a primary goal of community ecology. The number of interactions and the way in which those interactions organise themselves as individuals, small groups, and the whole community can play an important role in predicting how ecological communities will respond to disturbances. In this thesis, we investigated variation in network structure at several scales both empirically and in a theoretical context. Our first hypothesis was that the structural role of species in a variable system would show little variation, despite high levels of species turnover and a fragmented landscape. In a collaboration with Riikkaa Kaartinen and Tomas Roslin, we studied the distribution of species’ roles at three scales in host-parasitoid networks collected from a fragmented forest in Finland. We found that species’ roles were remarkably consistent through time and in the presence of species turnover. These results suggest that species’ roles may be an intrinsic property of species and may be predictable over spatial and temporal scales. Our second study investigated the structural variation of simulated ecological networks and the relationship between structural variation and whole-network measures of network organization, such as connectance, nestedness, and modularity. We quantified structural variation of networks at three scales, macro-scale, motif-scale, and participation scale. These scales represent whole-network measures (macro-scale), sub-network measures (motifs – small groups of interacting species), and individual measures (motif participation). We compared the variation in these structures to connectance, nestedness, and modularity. We found that at fixed levels of connectance, nestedness, and modularity, the motif profiles of networks and the distribution of species across those profiles showed remarkable dissimilarity. This result suggests that networks displaying similar macro-scale structural measures can be composed of vastly different motif- and participation-scale structures. Together, the work that makes up this thesis suggests that we should give more attention to the meso-scale structures of ecological networks. As the more detailed perspective of motifs can capture additional detail about the structure of empirical networks, and as a result, provide a clearer picture of ecological communities. In addition, we found that the particular species themselves can have a significant impact on the meso-scale structure and, in some cases, may impose strict limitations on what interactions can occur within a community. This has important implications for our understanding of how ecological networks are built and maintained, and thereby for our understanding of the stability and resilience of ecological communities.

This thesis studies certain aspects of the global properties, including geometric and arithmetic, of the moduli spaces of complex structures of some special Calabi-Yau threefolds (B-model), and of the corresponding topological string partition functions defined from them which are closely related to the generating functions of Gromov-Witten invariants of their mirror Calabi-Yau threefolds (A-model) by the mirror symmetry conjecture. / Mathematics

Purpose – Previously, modularity has mainly been studied in a production context. This paper highlights the opportunities and challenges of a modular strategy in an internationalisation context. It identifies which module components become active when entering new markets and suggests a model for how a modular internationalisation architecture can be designed. Design/methodology/approach – Results from a single case study of a multinational corporation in the vehicle industry, where managers of different departments involved in the internationalisation process support the possibility to create a modular internationalisation architecture. Findings – The findings suggest that the most important opportunities arising from modularity when entering new markets are the clear structure and shorter time to market. The main challenges to overcome are the risk of loss of flexibility and the issues of designing a modular architecture. Based on the key components in the case firm, one initial project-based departmentalised matrix structure is designed which can also help overcome the issues of choosing between standardisation and adaptation. Practical implications – The modular internationalisation architecture may help managers in multinational corporations who are already working with modularity in production to also organise the internal structure of their internationalisation process. Originality/value – This study includes a new model for multinational corporations entering new markets – the modular internationalisation architecture – which makes it possible to structure processes depending on internationalisation factors. The model should be seen as an initial suggestion of how a modular internationalisation architecture can be designed, but it may need to be further developed and tested. Keywords – International business, Internationalisation strategy, Organisational structure, Modularity, Modular processes, Modules, Components Paper type – Master’s thesis

The fundamentally fluctuating nature of the strength of a wireless link poses a significant challenge when seeking to achieve reliable communication at high data rates. Common sense, supported by information theory, tells us that one can move closer towards achieving higher data rates if the transmitter is provided with a priori knowledge of the channel. Such channel knowledge is typically provided to the transmitter by a feedback channel that is present between the receiver and the transmitter. The quality of information provided to the transmitter is proportional to the bandwidth of this feedback channel. Thus, the design of feedback channels is a key aspect in enabling high data rates. In the past, these feedback channels have been designed locally, on a link-by-link basis. While such an approach can be globally optimal in some cases, in many other cases, this is not true. In this thesis, we identify various settings in wireless networks, some already a part of existing standards, others under discussion in future standards, where the design of feedback channels is a problem that requires global, network-wide optimization. In general, we propose the treatment of feedback bandwidth as a network-wide resource, as the next step en route to achieving Gigabit wireless. Not surprisingly, such a global optimization initiative naturally leads us to the important issue of computational efficiency. Computational efficiency is critical from the point-of-view of a network provider. A variety of optimization techniques are employed in this thesis to solve the large combinatorial problems that arise in the context of feedback allocation. These include dynamic programming, sub-modular function maximization, convex relaxations and compressed sensing. A naive algorithm to solve these large combinatorial problems would typically involve searching over a exponential number of possibilities to find the optimal feedback allocation. As a general theme, we identify and exploit special application-specific structure to solve these problems optimally with reduced complexity. Continuing this endeavour, we search for more intricate structure that enables us to propose approximate solutions with significantly-reduced complexity. The accompanying analysis of these algorithms studies the inherent trade-offs between accuracy, efficiency and the required structure of the problem. / text

This dissertation provides a capability creation perspective on the story of China’s technological catching up, or resurgence, if viewed from a broader historical perspective. Since the first Asian tigers caught up to modern technological standards (e.g., South Korea, Singapore), two schools of thought have dominated causal explanations (Nelson and Pack, 1999). The first perspective is the conventional accumulation approach, which attributes the major share of growth to the accumulation of physical and human capital, and views learning as a more-or-less automatic byproduct of those investments. The second perspective is the assimilation approach, which emphasizes the arduous learning, risk-taking entrepreneurship, and innovation that is involved in the process and argues that the former proposition neglects this aspect of the endeavour and may therefore lead to erroneous estimates. This dissertation focuses on the second school of thought. Compared to the first-tier Asian tigers, the second-tier tigers, of which China is representative, pose many challenges to the assimilation approach. First, the sheer size of the country results in an unusual scale and scope of activities and interactions in any field. Second, the long history of civilization in China suggests that many modern phenomena have historical roots that are unknown to outsiders and invisible and complex to insiders. The present study aims to contribute a small piece of the puzzle to our understanding of the big picture. By providing an in-depth study of the Chinese information and communication technologies (ICT) sector, this study explores changes that have occurred in the three key building blocks of capability creation; specifically, the sourcing, generation, and appropriation of technological knowledge. A qualitative case study approach was employed for the main, empirical part of the study, which consists of extensive firm-level interviews. Complementary statistical data, including patent data and historical archives, were used to provide context and a deeper look into the study topic. The results are described in five articles. The first article presents establishing overseas research and development (R&D) laboratories as one of the major learning methods for overcoming disadvantages related to dislocation from technology sources and advanced markets. This approach allows China to search for industry-relevant scientific knowledge rather than adopting ready-made technologies introduced by western multinational enterprises in China. The second article describes the modularity-in-design approach, which opens new windows of opportunity for technological advancement. The lack of essential intellectual property rights (IPRs) acts as a key inducement and a factor-saving bias that influences the direction of innovation. When both (international) competitiveness and learning are involved in the catching-up process, the development of industry-wide capability becomes a particularly vital aspect of indigenous innovation. The third article describes the geographic consequences of historically planted industrial capabilities in China’s inland regions, which impact the absorption of different types of industrial knowledge. Fields of industry that are densely populated with patents- IPR thickets- represent a novel situation that was not experienced to the same extent by nations whose technological development occurred earlier. This thesis dedicates two articles to this dimension of knowledge appropriation. The fourth article describes the duality of Chinese ICT patenting, and the fifth article identifies an ambidextrous strategy that depends on where the major competition emerges. In general, the decision to patent and the extent of patenting are determined by four factors: a) the distance to the frontier (Aghion et al., 1997) particularly for technology; b) the nature of the technology (Teece, 1986), but with a rural extension in the case of China; c) the specificities of information (Arrow, 1962) that are embodied in a firm’s origins in China; and d) the supporting institutions that co-evolve in that process. Learning proceeds at different levels: that of individuals, firms, industries, and nations.   This dissertation provides an industry-level perspective on learning and innovation-based technological advancement. / from developing economy to global high-tech competitiveness - the case of Chinese ICT expansion

Originally presented as the author's thesis (Ph. D.)--Leiden University. / Includes bibliographical references (p. 265-280) and index.

Originally presented as the author's thesis (Ph. D.)--Leiden University. / Includes bibliographical references (p. 265-280) and index.

Originally presented as the author's Thesis (Ph. D.)--Leiden University. / Includes bibliographical references (p. 265-280) and index.

The results of evolution can be inferred from comparative studies of related organisms. In this doctoral thesis, I use phylogenetic comparative methods along side geometric morphometrics to analyse shape variation in order to infer evolution of the caecilian skull. Caecilians are elongate, limbless amphibians that superficially resemble snakes or earthworms, and use their head as a locomotory organ. I characterise large-scale patterns of cranial morphological diversity and quantify variation across the main family-level clades by describing patterns relating to phylogeny, disparity and ecology. Then I examine the origins and evolution of morphological variation in the skull by describing patterns relating to morphological integration and modularity. This thesis demonstrates a variety of existing statistical techniques that can be used to infer processes from large-scale evolutionary patterns in morphological data using non model organisms. Throughout the thesis, I show that the evolution of the caecilian skull to be multifaceted. On the patterns of diversity, the most striking is a "starburst" arrangement in shape space, which suggests that early in caecilian evolution ancestral lineages traversed greater expanses of the shape space, while subsequent phylogenetic divergence within the main clades entailed less morphological diversification. This may be related to early diversification into different ecological-niches, yet more data are needed to test this. The clades differ considerably in their cranial disparity, but there appears to be no unified pattern across the whole order that indicates disparity is coupled with clade age or speciation events. I show that aquatic species are more diverse than their terrestrial relatives, and that there is convergence of cranial shape among dedicated burrowers with eyes covered by bone. On the patterns of morphological integration and modularity, another remarkable finding is the caecilian cranium is modular with respect to two functional regions, the snout and the back of the cranium. Modularity is important for understanding the evolution of this structure. The main elements of the caecilian anterior skeleton, the cranium, mandible and atlas vertebra, reveal different patterns of morphological integration, suggesting different developmental and evolutionary processes are involved in sorting and maintaining new variation of each structure. Allometry is an important component of integration in each of the structures. Covariation of the cranium-mandible after size correction is significant and follows the same direction of shape change across all levels and as shown for allometry. In contrast, covariation of the cranium-atlas follows different directions at each level. These results suggest the two main joint of the caecilian skull differ substantially in their origin and evolution. I discuss the contribution made in this thesis to caecilian and evolutionary biology and offer an outlook of how theses findings can be used to initiate future studies to better understand of the evolution of the caecilian skull.