Right-Financing Security Sector Reform

Security sector reform (SSR) in post-conflict environments encompasses a broad range of efforts to improve capacity, governance, performance, and sustainability. The fiscal implications of SSR decisions often are neglected, however. The negative consequences of this neglect include unsustainable reforms, the squeezing out of other vital sectors, and ultimately under-provision of security itself. This paper argues for a “right-financing” approach to SSR that strikes an appropriate balance between current needs and the goal of building a fiscally sustainable security sector. The paper offers four policy proposals: first, build fiscal dimensions of the security sector into peace agreements, post-conflict needs assessments, development strategies, and expenditure planning; second, align short-run policies with long-term budgetary realities; third, move to a “service-delivery” model based on provision of law-and-order and justice services to the citizens; and finally, strengthen international capacities to support these right-financing policies.Security sector reform; fiscal sustainability; service delivery

Evaluation of Tweedie exponential dispersion model densities by Fourier inversion

The Tweedie family of distributions is a family of exponential dispersion models with power variance functions V (μ) = μ^p for p not between (0, 1). These distributions do not generally have density functions that can be written in closed form. However, they have simple moment generating functions, so the densities can be evaluated numerically by Fourier inversion of the characteristic functions. This paper develops numerical methods to make this inversion fast and accurate. Acceleration techniques are used to handle oscillating integrands. A range of analytic results are used to ensure convergent computations and to reduce the complexity of the parameter space. The Fourier inversion method is compared to a series evaluation method and the two methods are found to be complementary in that they perform well in different regions of the parameter space

URBAN STRUCTURE: ITS ROLE IN URBAN GROWTH, NET NEW BUSINESS FORMATION AND INDUSTRIAL CHURN

Cities are the “engines of growth” because entrepreneurial and cre-ative activities are concentrated in cities. This suggests that cities grow by host-ing new businesses and “churning” industries advantageously. In so doing, cities need to adapt their spatial structure to mitigate negative externalities. Our previous paper (Lee and Gordon 2007) found that the links between urban structure and growth vary across metro size: more clustering in small metros and more dispersion in large metros were associated with faster employment growth. In this paper, we extend our research to investigate to what extent ur-ban spatial structure variables – dispersion and polycentricity – influence net new business formation (NNBF) and industrial “churning” in a cross-section of 79 U.S. metropolitan areas in the 2000s. The results of least squares regression and locally weighted regression analyses are mixed. OLS results for recent years fail to replicate our results for the 1990s. But applying a more powerful LOESS approach does give results for spatial impacts on NNBF and industrial churning that are consistent with the links between spatial structure and urban growth found in the earlier paper.URBAN SPATIAL STRUCTURE, URBAN GROWTH, NET NEW BUSINESS FORMATION (NNBF), INDUSTRIAL CHURN

Grid generation for the solution of partial differential equations

A general survey of grid generators is presented with a concern for understanding why grids are necessary, how they are applied, and how they are generated. After an examination of the need for meshes, the overall applications setting is established with a categorization of the various connectivity patterns. This is split between structured grids and unstructured meshes. Altogether, the categorization establishes the foundation upon which grid generation techniques are developed. The two primary categories are algebraic techniques and partial differential equation techniques. These are each split into basic parts, and accordingly are individually examined in some detail. In the process, the interrelations between the various parts are accented. From the established background in the primary techniques, consideration is shifted to the topic of interactive grid generation and then to adaptive meshes. The setting for adaptivity is established with a suitable means to monitor severe solution behavior. Adaptive grids are considered first and are followed by adaptive triangular meshes. Then the consideration shifts to the temporal coupling between grid generators and PDE-solvers. To conclude, a reflection upon the discussion, herein, is given

Robot Navigation in Unseen Spaces using an Abstract Map

Human navigation in built environments depends on symbolic spatial information which has unrealised potential to enhance robot navigation capabilities. Information sources such as labels, signs, maps, planners, spoken directions, and navigational gestures communicate a wealth of spatial information to the navigators of built environments; a wealth of information that robots typically ignore. We present a robot navigation system that uses the same symbolic spatial information employed by humans to purposefully navigate in unseen built environments with a level of performance comparable to humans. The navigation system uses a novel data structure called the abstract map to imagine malleable spatial models for unseen spaces from spatial symbols. Sensorimotor perceptions from a robot are then employed to provide purposeful navigation to symbolic goal locations in the unseen environment. We show how a dynamic system can be used to create malleable spatial models for the abstract map, and provide an open source implementation to encourage future work in the area of symbolic navigation. Symbolic navigation performance of humans and a robot is evaluated in a real-world built environment. The paper concludes with a qualitative analysis of human navigation strategies, providing further insights into how the symbolic navigation capabilities of robots in unseen built environments can be improved in the future.Comment: 15 pages, published in IEEE Transactions on Cognitive and Developmental Systems (http://doi.org/10.1109/TCDS.2020.2993855), see https://btalb.github.io/abstract_map/ for access to softwar