Can we rationally learn to coordinate?

In this paper we examine the issue whether individual rationality considerations are sufficient to guarantee that individuals will learn to coordinate. This question is central in any discussion of whether social phenomena (read: conventions) can be explained in terms of a purely individualistic approach. We argue that the positive answers to this general question that have been obtained in some recent work require assumptions which incorporate some convention. This conclusion may be seen as supporting the viewpoint of institutional individualism in contrast to psychological individualism.     

Faster algorithm to find anti-risk path between two nodes of an undirected graph

For a weighted 2-edge connected graph G=(V,E), we are to find a “minimum risk path” from source s to destination t. This is a shortest s?t path under the assumption that at most one edge on the path may be blocked. The fact that the edge is blocked is known only when we reach a site adjacent to the blocked edge. If n and m are the number of nodes and edges of G, then we show that this problem can be solved in O(n ²) time using only simple data structures. This is an improvement over the previous O(mn+n ²logn) time algorithm. Moreover, with use of more complicated data structures like Fibonacci Heaps and transmuters the time can be further reduced to O(m+nlogn).     

Analysis of strategic plans to assess planning for sustainability of comprehensive community initiatives

In order to achieve the intended impact on a community, comprehensive community initiatives must sustain programs once they have been implemented. However, planning for sustainability is challenging and is rarely incorporated in the planning process of an initiative. The current study examined 19 5-year plans developed during the planning phase of the Comprehensive Strategy for Serious, Violent and Chronic Juvenile Offenders. Quantitative and qualitative methods were employed to assess the extent to which the construct of sustainability was incorporated. The plan analysis was supplemented with results from other components of the complex evaluation design implemented as part of the process evaluation of Comprehensive Strategy. Results suggested that sustainability was not accounted for during the planning phase of this initiative. The implications of these findings, including the importance of planning for sustainability in order to achieve sustainability, are discussed.     

Maximum cardinality neighbourly sets in quadrilateral free graphs

Neighbourly set of a graph is a subset of edges which either share an end point or are joined by an edge of that graph. The maximum cardinality neighbourly set problem is known to be NP-complete for general graphs. Mahdian (Discret Appl Math 118:239–248, 2002) proved that it is in polynomial time for quadrilateral-free graphs and proposed an \(O(n^{11})\) algorithm for the same, here n is the number of vertices in the graph, (along with a note that by a straightforward but lengthy argument it can be proved to be solvable in \(O(n^5)\) running time). In this paper we propose an \(O(n^2)\) time algorithm for finding a maximum cardinality neighbourly set in a quadrilateral-free graph.     

Ten steps to making evaluation matter

This paper proposes ten steps to make evaluations matter. The ten steps are a combination of the usual recommended practice such as developing program theory and implementing rigorous evaluation designs with a stronger focus on more unconventional steps including developing learning frameworks, exploring pathways of evaluation influence, and assessing spread and sustainability. Consideration of these steps can lead to a focused dialogue between program planners and evaluators and can result in more rigorously planned programs. The ten steps can also help in developing and implementing evaluation designs that have greater potential for policy and programmatic influence. The paper argues that there is a need to go beyond a formulaic approach to program evaluation design that often does not address the complexity of the programs. The complexity of the program will need to inform the design of the evaluation. The ten steps that are described in this paper are heavily informed by a Realist approach to evaluation. The Realist approach attempts to understand what is it about a program that makes it work.     

Keeping up with the Neighbors: Social Interaction in a Market Economy

We consider a world in which individuals have private endowments and trade in markets while their utility is negatively affected by the consumption of their neighbors. Our interest is in understanding how the social structure of comparisons, taken together with the familiar fundamentals of the economy (endowments, technology, and preferences), shapes equilibrium prices, allocations, and welfare. We show that equilibrium prices and consumption are a function of a single network statistic: centrality. An individual's “centrality” is given by the weighted sum of paths of different lengths to all others in a social network. In particular, prices are proportional to the sum of centralities, and an individual's consumption depends on how central she is relative to others in the network. Inequalities in wealth and connections reinforce each other in markets: A transfer of resources from less to more central agents raises prices. As segregated communities become integrated, the poor lose while the rich gain in utility! (JEL: D5, D6, D85)     

A Noncooperative Model of Network Formation

We present an approach to network formation based on the notion that social networks are formed by individual decisions that trade off the costs of forming and maintaining links against the potential rewards from doing so. We suppose that a link with another agent allows access, in part and in due course, to the benefits available to the latter via his own links. Thus individual links generate externalities whose value depends on the level of decay/delay associated with indirect links. A distinctive aspect of our approach is that the costs of link formation are incurred only by the person who initiates the link. This allows us to formulate the network formation process as a noncooperative game. We first provide a characterization of the architecture of equilibrium networks. We then study the dynamics of network formation. We find that individual efforts to access benefits offered by others lead, rapidly, to the emergence of an equilibrium social network, under a variety of circumstances. The limiting networks have simple architectures, e.g., the wheel, the star, or generalizations of these networks. In many cases, such networks are also socially efficient.     

Algorithms for testing occurrences of length 4 patterns in permutations

In this paper linear time sequential and optimal parallel algorithms for testing pattern involvement for all length 4 permutations are described. This is an improvement as the previous best sequential algorithms, for most of these pattern require \(O(n\log n)\) time. Our parallel algorithms can be implemented in \(O(\log n)\) time with \(n/\log n\) processors on the CREW PRAM model, or alternatively in \(O(\log \log \log n)\) time with \(n/\log \log \log n\) processors on a CRCW PRAM PRAM model. Parallel algorithm can also be implemented in constant time with \(n\log ^3 n\) processors on a CRCW PRAM model. The previous best parallel algorithms were available for only some of these patterns and took \(O(\log n)\) time with n processors on the CREW PRAM model.     

FLEXIBILITY,ADAPTABILITY, AND EFFICIENCY IN MANUFACTURING SYSTEMS

There are many different approaches and conceptualizations of flexibility in the present literature. This lends itself to a lack of clarity and can result in confusion on the central concept. Here we identify shortcomings in the existing literature. To clarify some of the important concepts, we distinguish between flexibility (ability to change states), adaptability (ability to change within a state), and efficiency (resources utilized). To illustrate such distinctions, we present a capacity expansion model that takes flexibility and adaptability into consideration. Numerical examples show how the concepts of flexibility and adaptability can be used in manufacturing.     

Using Exploratory Spatial Data Analysis to Leverage Social Indicator Databases: The Discovery of Interesting Patterns

With the proliferation of social indicator databases, the need for powerful techniques to study patterns of change has grown. In this paper, the utility of spatial data analytical methods such as exploratory spatial data analysis (ESDA) is suggested as a means to leverage the information contained in social indicator databases. The principles underlying ESDA are illustrated using a study of clusters and outliers based on data for a child risk scale computed for countries in the state of Virginia. Evidence of spatial clusters of high child risks is obtained along the Southern region of Virginia. The utility of spatial methods for state agencies in monitoring social indicators at various localities is discussed. A six-step framework that integrates spatial analysis of key indicators within a monitoring framework is presented; we argue that such a framework could be useful in enhancing communication between State and local planners. Given cost considerations, the original color figures have been printed in black and white in this article. The color figures can be obtained from http://www.chs.med.ed.ac.uk/rubhc/evaluation/