Are All Policy Decisions Equal? Explaining the Variation in Media Coverage of the UK Budget

A country's budget is one of the most important public policy instruments, as it establishes the government's policy priorities and has the potential to determine winners and losers. The budget, however, is a mixture of different components and these get varying degrees of attention in the media. Drawing on sociology of news research, this paper seeks to explain this heterogeneous coverage of a budget's policy decisions. To do so, it uses a unique data set of over 5,000 articles of press coverage of six UK budgets (2008–2012). These articles are coded for the presence/absence of each of the budget's policy decision, via automated content analysis. On the basis of a multivariate negative binomial model, we find that the salience of a policy decision in the coverage is determined by its cost, whether it is negative (i.e., tax hikes and spending cuts) or positive, the income group that is the most affected by it, and the level of attention given to it by the government.     

Neighbourhood food environments revisited: When food deserts meet food swamps

This study uses service area–based coverage and various count regression methods to assess neighbourhood-level healthy and unhealthy food environments, and food access associated with different socio-economic groups in Edmonton, Canada. We identify three types of vulnerable neighbourhoods according to different food environments: food deserts (i.e., neighbourhoods lack sufficient access to healthy foods); food swamps (i.e., neighbourhoods have excess access to unhealthy foods); and those with overlaps of food swamps and food deserts. We also identify neighbourhoods with superior access to healthy foods (i.e., food oases). Additionally, our results from regression analyses indicate: (1) child population is negatively associated with both healthy and unhealthy food resources; (2) good access to public transportation is associated with good coverage of all healthy food outlets and convenience stores; and (3) deprived neighbourhoods with higher percentages of minority populations have better coverage of both healthy and unhealthy foods in general. The results from this study can help the City of Edmonton identify the key neighbourhoods with high potential for local business and the hotspot neighbourhoods that require particular support. Tailored strategies are proposed to effectively and efficiently improve food environments with limited resources.     

Location Modeling Utilizing Maximum Service Distance Criteria

The location set-covering problem (LSCP) and the maximal covering location problem (MCLP) have been the subject of considerable interest. As originally defined, both problems allowed facility placement only at nodes. This paper deals with both problems for the case when facility placement is allowed anywhere on the network. Two theorems are presented that show that when facility placement is unrestricted, for either the LSCP or MCLP at least one optimal solution exists that is composed entirely of points belonging to a finite set of points called the network intersect point set (NIPS). Optimal solution approaches to the unrestricted site LSCP and MCLP problems that utilize the NIPS and previously developed solution methodologies are presented. Example solutions show that considerable improvement in the amount of coverage or the number of facilities needed to insure total coverage can be achieved by allowing facility placement along arcs of the network. In addition, extensions to the arc-covering model and the ambulance-hospital model of ReVelle, Toregas, and Falkson are developed and solved.     

Computational Comparison of Five Maximal Covering Models for Locating Ambulances

This article categorizes existing maximum coverage optimization models for locating ambulances based on whether the models incorporate uncertainty about (1) ambulance availability and (2) response times. Data from Edmonton, Alberta, Canada are used to test five different models, using the approximate hypercube model to compare solution quality between models. The basic maximum covering model, which ignores these two sources of uncertainty, generates solutions that perform far worse than those generated by more sophisticated models. For a specified number of ambulances, a model that incorporates both sources of uncertainty generates a configuration that covers up to 26% more of the demand than the configuration produced by the basic model.     

ENHANCING SPATIAL REPRESENTATION IN PRIMARY AND SECONDARY COVERAGE LOCATION MODELING*

ABSTRACT An important goal in many planning contexts is maximizing primary and secondary (or backup) coverage while locating a specified number of service facilities. In general, we are interested in providing the greatest level of coverage to demand that is continuously distributed across space. A critical issue is how to represent continuous demand in coverage analysis, reducing or eliminating error and uncertainty. This paper evaluates representation issues in primary and secondary coverage location modeling. To overcome representational limitations, enhancements for spatial coverage abstraction are introduced and incorporated in a mathematical optimization model. In addition to model improvements, this paper introduces a new and novel error assessment approach arising due to the existence of multiple objectives. Surveillance sensor siting in an urban area is utilized to assess enhanced modeling capabilities.     

Cost-efficient Reserve Site Selection Favoring Persistence of Threatened and Endangered Species

This article formulates and tests set covering and related models with spatial characteristics for selecting sites that provide habitat for species that are identified as "critical" (e.g., typically threatened, endangered, or rare), thereby enhancing their persistence. The first two models presented require the creation of a core area for each critical species and a buffer zone surrounding the core, with and without being constrained to include at least one representation of each and every common (i.e., noncritical) species. The final model aims at minimizing costs of protecting predetermined numbers of common species while all critical species remain covered and buffered. These models are implemented for occurrence data of terrestrial mammals in Oregon. They enable, among other things, a comparison between the budgetary impacts of reserve networks with and without buffering rings for critical species, and a determination of the marginal cost of common species protection.     

The Spatial Structuring of Central Places

The spatial structuring of “classical” central place systems is the primary concern of this research. Emphasizing the development of such systems from basic spatial relations between centers and hinterland locations (rather than as a result of an underlying geometry of regions), this paper takes an optimization approach to the siting of central places in a single-good system. The objective function is shown to be one that maximizes both market coverage of demand and market overlap. Access to this objective is given through the natural slack covering model.     

Two New Location Covering Problems: The Partial P-Center Problem and the Partial Set Covering Problem

Two new covering problems are introduced. The partial covering P-center problem minimizes a coverage distance in such a way that a given fraction of the population is covered. The partial set covering problem seeks the minimum number of facilities needed to cover an exogenously specified fraction of the population within a given coverage distance. The problems are formulated as integer linear programming problems. Bisection search algorithms are outlined for the two problems. The search algorithm repeatedly solves a Lagrangian relaxation of the maximal covering problem. Computational results for the Lagrangian relaxation of the maximal covering problem and for the bisection search algorithms are presented on problems with up to 150 nodes.     

Analysis of Errors Due to Demand Data Aggregation in the Set Covering and Maximal Covering Location Problems

In this paper, we extend the concepts of demand data aggregation error to location problems involving coverage. These errors, which arise from losses in locational information, may lead to suboptimal location patterns. They are potentially more significant in covering problems than in p-median problems because the distance metric is binary in covering problems. We examine the Hillsman and Rhoda (1978) Source A, B, and C errors, identify their coverage counterparts, and relate them to the cost and optimality errors that may result. Three rules are then presented which, when applied during data aggregation, will reduce these errors. The third rule will, in fact, eliminate all loss of locational information, but may also limit the amount of aggregation possible. Results of computational tests on a large-scale problem are presented to demonstrate the performance of rule 3.     

Two New Location Covering Problems: The Partial P-Center Problem and the Partial Set Covering Problem

Two new covering problems are introduced. The partial covering P-center problem minimizes a coverage distance in such a way that a given fraction of the population is covered. The partial set covering problem seeks the minimum number of facilities needed to cover an exogenously specified fraction of the population within a given coverage distance. The problems are formulated as integer linear programming problems. Bisection search algorithms are outlined for the two problems. The search algorithm repeatedly solves a Lagrangian relaxation of the maximal covering problem. Computational results for the Lagrangian relaxation of the maximal covering problem and for the bisection search algorithms are presented on problems with up to 150 nodes.     

The Importance of Attention Diversity and How to Measure It

Studies of political attention often focus on attention to a single issue, such as front‐page coverage of the economy. However, examining attention to a single issue without accounting for the agenda as a whole can lead to faulty assumptions. One solution is to consider the diversity of attention; that is, how narrowly or widely attention is distributed across items (e.g., issues on an agenda or, at a lower level, frames in an issue debate). Attention diversity is an important variable in its own right, offering insight into how agendas vary in their accessibility to policy problems and perspectives. Yet despite the importance of attention diversity, we lack a standard for how best to measure it. This paper focuses on the four most commonly used measures: the inverse Herfindahl Index, Shannon's H, and their normalized versions. We discuss the purposes of these measures and compare them through simulations and using three real‐world datasets. We conclude that both Shannon's H and its normalized form are better measures, minimizing the danger of spurious findings that could result from the less sensitive Herfindahl measures. The choice between the Shannon's H measures should be made based on whether variance in the total number of possible items (e.g., issues) is meaningful.     

Spatial/temporal mismatch: a conflation protocol for Canada Census spatial files

The Canada census is one of the chief sources of demographic and socio-economic data for researchers in this country. Census variables are linked to geography files that allow researchers using geographic information systems (GIS) to view and analyze spatial data. Some of the most useful analysis, however, is based on changes in attribute values over time and space. Analysis of spatio- temporal events such as shifting migration patterns or changes in the distribution of health status permits a more dimensioned perspective than the viewing of static spatial phenomena. The analysis of spatio-temporal phenomena is limited by major changes in the spatial framework (e.g., location of road networks and other spatial entities) between national censuses. This paper addresses this limitation by (i) illustrating the extent of spatial mismatch between the 1996 and the 2001 census; (ii) examining attempts to rectify this problem in other jurisdictions and (iii) presenting a 'made-in-Canada' solution for conflation of census geometries. We believe that this solution will enhance the ability of Canadian researchers to describe and analyze socio-economic, health and demographic shifts across time and space. The research is supported by an ftp site for downloading the census geography rectification software presented in this paper.     

Numerical Simulation and Seismic Fragility Analysis of a Self-Centering Steel MRF with Web Friction Devices

This article presents the seismic fragility analysis of a self-centering steel moment-resisting frame (SC-MRF) with web friction devices. A detailed numerical model of the SC frame was developed using the Open System for Earthquake Engineering Simulation (OpenSees) and the elastoplastic responses of the SC-MRF were studied, including the strength degradation under cyclic loading, tendon rupture, beam buckling, bolt bearing and friction loss, etc. The proposed simulation approach is validated by comparing the simulated results with those in existing hybrid-simulation tests, quasi-static pushover test and low cyclic tests, where good agreement is observed. In addition to the well-established performance limit states (i.e., immediate occupancy, collapse prevention and global dynamic instability), two unique performance limit states (i.e., the recentering and repairable limit states) are defined for the SC-MRF. Finally, incremental dynamic analyses are conducted to evaluate the seismic fragilities regarding the five performance limit states.     

Seismic Response of Bridges Subjected to Different Earthquake Types Using IDA

Incremental Dynamic Analysis (IDA) was used to evaluate the seismic response of straight, continuous 4-span bridges with different sub-structure configurations. Three different record sets were chosen to represent three different earthquake types which can occur for a site such as Vancouver (i.e., crustal, subduction interface, and subduction inslab earthquakes). Seventy eight records were considered in each set (i.e., a total of 234 records) and the capacities of the bridges were evaluated using a fast IDA algorithm. A simplified method to account for the effects of spectral shapes was used. Different subsets of the records with specific characteristics were also used in the IDA. The bridges were designed and evaluated for two different design force modification factors and bridges with different degrees of irregularity were studied. Comparisons of the IDA results obtained indicated that in most of the cases the interface record sets resulted in lower median collapse capacities and hence were the most critical of the ground motions studied.     

Nonlinear Response of RC Framed Buildings with Isolation and Supplemental Damping at the Base Subjected to Near-Fault Earthquakes

The nonlinear seismic response of base-isolated framed buildings subjected to near-fault earthquakes is studied to analyze the effects of supplemental damping at the level of the isolation system, commonly adopted to avoid overly large isolators. A numerical investigation is carried out with reference to two- and multi-degree-of-freedom systems, representing medium-rise base-isolated framed buildings. Typical five-story reinforced concrete (RC) plane frames with full isolation are designed according to Eurocode 8 assuming ground types A (i.e., rock) and D (i.e., moderately soft soil) in a high-risk seismic region. The overall isolation system, made of in-parallel high-damping-laminated-rubber bearings (HDLRBs) and supplemental viscous dampers, is modeled by an equivalent viscoelastic linear model. A bilinear model idealizes the behavior of the frame members. Pulse-type artificial motions, artificially generated accelerograms (matching EC8 response spectrum for subsoil classes A or D) and real accelerograms (recorded on rock- and soil-site at near-fault zones) are considered. A supplemental viscous damping at the base is appropriate for controlling the isolator displacement, so avoiding overly large isolators; but it does not guarantee a better performance of the superstructure in all cases, in terms of structural and non structural damage, depending on the frequency content of the seismic input. Precautions should be taken with regard to near-fault earthquakes, particularly for base-isolated structures located on soil-site.     

Analytical Seismic Assessment of a Tall Long-Span Curved Reinforced-Concrete Bridge. Part I: Numerical Modeling and Input Excitation

The seismic response of bridges is affected by a number of modeling considerations, such as pier embedment, buried pile caps, seat-type abutments, pounding, bond slip and architecturally flared part of piers, and loading considerations, such as non-uniform ground excitations and orientation of ground motion components, which are not readily addressed by design codes. This article addresses a methodology for the nonlinear static and dynamic analysis of a tall, long-span, curved, reinforced-concrete bridge, the Mogollon Rim Viaduct. Various modeling scenarios are considered for the bridge components, soil-structure interaction system, and materials, i.e., concrete and reinforcing steel, covering all its geotechnical and structural aspects based on recent advances in bridge engineering. Various analysis methodologies (nonlinear static pushover, time history response to uniform and spatially variable seismic excitations, and incremental dynamic analyses) are performed. For the dynamic analyses, a suite of nine earthquake accelerograms are selected and their characteristics are investigated using seismic intensity parameters. A recently developed approach for the generation of non-uniform seismic excitations, i.e., spatially variable simulations conditioned on the recorded time series, is used. Methods for the evaluation of structural performance are discussed and their limitations addressed. The numerical results of the seismic assessment of the Mogollon Rim Viaduct are presented in the companion article (Part II). The sensitivity of the bridge response to the adopted modeling, loading and analyzing strategies, as well as the correlation between structural damage and seismic intensity parameters are examined in detail.     

Mind the Gaps: The Evolution of Regional Earnings Inequalities in the U.K., 1982–1997

In this paper we apply earnings equations for U.K. regions over 1982–1997. We find evidence of rapid convergence across regions regarding the determinants of individual wages (i.e., regional fixed-effects, gender gaps, and returns to education and experience). In contrast, data on average regional earnings point to a worsening of U.K. regional inequalities and a rise in the North-South gap. Education accounts for most of the discrepancy between aggregate divergence and disaggregated convergence. First, London gained because its workforce became relatively more educated over the period. Second, returns to education increased nationwide, which favored the most educated regions (i.e., London). Third, returns to education were initially lower in London but they (partially) caught up with the rest of the country. Had returns to education and their distribution across U.K. regions remained stable over the period, the U.K. North-South divide would have decreased.     

Organ donation,genetics, race and culture: The making of a medical problem (Respond to this article at http://www.therai.org.uk/at/debate)

Within transplant medicine in the UK, the relationship between organ donation and ethnicity has been characterized as problematic, with a specific focus on the apparent reluctance of black and Asian people in Britain to act as blood and organ donors. In this article, we show that transplant medicine, in trying to work out a solution to this ‘problem’, has culturalized the issue by treating it as something that falls outside its own domain of practice, with racialized responsibility being entrenched through the mapping of donor pools to cultural difference. We urge a rethink of what is increasingly becoming a one‐sided discussion. A concentration on ethnicity alone fails to take into account the ways in which low donation rates become a problem as a result of the specific ways in which transplant medicine in the UK has been configured and reconfigured over time, constituting different publics along the way. In order to understand the relationship between ethnicity and organ donation, it is important that we as anthropologists examine where and how the problem has in large part been forged (i.e., within transplant medicine), as much as where and in what terms that problem has been fixed in place (i.e., as a problem of black and minority ethnic publics).     

Macro-Modeling of Reinforced Concrete Structural Walls: State-of-the-Art

During the past decades, various analytical macroscopic models of structural walls have been developed for simulating the seismic behavior of reinforced concrete (RC) walls. Due to the inherently complicated characteristics of RC walls, macroscopic models that can capture all the important response characteristics with good accuracy and applicability are very challenging to establish. A thorough review of the four main types of mathematical macro models of RC walls, i.e., the vertical-line-element-model, the 2-D shear panel element model, the equivalent truss model and the fiber-based model, is presented to discuss the methodology behind each model and examine the corresponding merits and disadvantages. Suggestions are also made for the further research of the macro modeling of structural walls.     

On Covering Problems and the Central Facilities Location Problem

A number of variations of facilities location problems have appeared in the research literature in the past decade. Among these are problems involving the location of multiple new facilities in a discrete solution space, with the new facilities located relative to a set of existing facilities having known locations. In this paper a number of discrete solution space location problems are treated. Specifically, the covering problem and the central facilities location problem are shown to be related. The covering problem involves the location of the minimum number of new facilities among a finite number of sites such that all existing facilities (customers) are covered by at least one new facility. The central facilities location problem consists of the location of a given number of new facilities among a finite number of sites such that the sum of the weighted distances between existing facilities and new facilities is minimized. Computational experience in using the same heuristic solution procedure to solve both problems is provided and compared with other existing solution procedures.