Capacity inverse minimum cost flow problem

Given a directed graph G=(N,A) with arc capacities u _ij and a minimum cost flow problem defined on G, the capacity inverse minimum cost flow problem is to find a new capacity vector [^(u)]\hat{u} for the arc set A such that a given feasible flow [^(x)]\hat{x} is optimal with respect to the modified capacities. Among all capacity vectors [^(u)]\hat{u} satisfying this condition, we would like to find one with minimum ||[^(u)]-u||\|\hat{u}-u\| value. We consider two distance measures for ||[^(u)]-u||\|\hat{u}-u\| , rectilinear (L ₁) and Chebyshev (L _∞) distances. By reduction from the feedback arc set problem we show that the capacity inverse minimum cost flow problem is NP\mathcal{NP} -hard in the rectilinear case. On the other hand, it is polynomially solvable by a greedy algorithm for the Chebyshev norm. In the latter case we propose a heuristic for the bicriteria problem, where we minimize among all optimal solutions the number of affected arcs. We also present computational results for this heuristic.     

Futurelessness,migration, or a lucky break: narrative tropes of the ‘blocked future’ among Serbian high school students

ABSTRACT

This article uses ethnographic discourse analysis to understand how Serbian high school students at ‘Belgrade Professional’ (BP) respond to coursework and discussions about their individual futures. Contextualizing the conversations at BP within broader local and international social forces, the paper shows how students’ perceptions of their future chances are mediated by both the school’s outdated promises of secure skilled employment and a broad understanding of Western liberal democracies as ‘meritocratic’. In short, I argue that BP students recognize the elective ‘choice biography’ as a real pathway to adulthood. However, they primarily imagine the choice biography as existing outside of Serbia, while feeling constrained by – even hostile to – such an idea within the country. To counter choice biography framings of futures in Serbia, students mobilize a discourse I call the ‘blocked future’, comprised of three related narrative tropes informed by the decades-long recession: domestic futurelessness, meritocracy abroad, and local chance. These narrative tropes illuminate the emerging cultural structures in Serbia which reflect how people cope with and processes the conflicting structural demands and unfulfilled promises of the post-socialist transition in everyday life.     

What’s off-centre of empire? Introduction to the special issue

ABSTRACT

In this Introduction, we discuss the aims of this publication along with guidelines to locate and connect the essays part of the edited volume. We start by highlighting the original contribution of our intervention in terms of what off-centring empire offers in relation to scholarship that de-centres empire. To us, this means to look at the processes, dynamics, and movements that connect empire (as a centre of power) to its peripheries (as a site of difference, struggles, and resistance). To be sure, attempts to off-centre and de-centre empire are related, relational, and they both commit to the project of challenging the centrality of empire, to confronting its lasting legacies and normative powers. Yet to off-centre, as we argue, is to focus on the electrifying force-field generated by the poles of imperial power, rather than oppose centre and peripheries to subvert their relationship. Our aim is to reveal the complex ways centre and periphery connect and distance with the aim to highlight emerging modes of counter-imperial practice. Further, this introduction serves as the opportunity to discuss the structure of the SI and its three main sections – Public Memory, Orientations, and More-than-human. Here we reflect upon how each essay brings to the fore a unique way to off-centre empire, and thus provide examples that may inspire future research. Finally, we highlight how conversations emerging from individual essays can be assembled and read into threads, pointing to multiple ways in which we seek to off-centre empire through empirical research.     

Are Targeted Unconditional Cash Transfers Effective? Evidence from a Poor Region in India

The paper is based on a well-focused and purposive field survey of 200 randomly selected sample households (HHs) from 20 villages of Odisha (the poorest state) in India, provides a critique of present institutional arrangements for delivery of social security measures-in terms of outreach and effectiveness. The exercise shows, on the one hand, the dissonance between below poverty line households and asset/wealth position of households and thus there is strong evidence of inclusion and exclusion errors and on the other, weak targeting efficiency and an important determinant of which seems to be what is called HH social/structural capital.     

Happiness and Pathways to Reach It: Dimension-Centred Versus Person-Centred Approach

The purpose of the present study was to explore the ways people achieve their happiness employing two approaches, i.e. a dimension-centred, focusing on the three orientations to happiness (orientation to pleasure, meaning, and engagement), and a person-centred, focusing on patterns of these three orientations within individuals. The predictive validity of individual orientations to happiness and their characteristic patterns for three aspects of subjective well-being was explored. Adult participants (N = 1,142; 33 % male) filled-in the Orientations to Happiness Questionnaire and the Mental Health Continuum-Long Form. Applying the dimension-centred approach, results suggested that all of the orientations represent possible and appropriate ways to achieve happiness. Person-centred analysis yielded four groups of individuals with similar profiles of ways towards happiness and membership of these groups was associated with individual’s well-being. Leading an empty life was associated with the poorest outcomes and full life with the highest well-being, with moderate well-being characterizing individuals pursuing pleasurable and meaningful life. More precisely, pleasurable life and meaningful life had relatively similar predictive value for psychological well-being but demonstrated discriminant validity for emotional and social well-being. This suggests that the profiles are meaningfully different and highlights the importance of the multiplicative influences of the three specific orientations to happiness.     

Goodness-of-fit test of the mark distribution in a point process with non-stationary marks

Three procedures for testing the hypothesis that the marks of the point process belong to a given family of distributions, where the marks are independent conditionally on an unknown non-stationary parametric field θ(x), are described. The unknown parametric field was estimated by a kernel estimator and the estimate included in the procedures. The asymptotic distribution of the kernel estimator was derived because it is required in some of the procedures to take into account the estimation uncertainty. The procedures were compared by a simulation study and applied to two real datasets. First, the terminal dates of Maya sites and second, the heights of trees that have fallen during storms.     

Limiting distribution of the number of clumps of palindromes in DNA

An important aspect in the analysis of long DNA sequences is to identify whether palindromes are over- or under-represented. The essential step in that direction is the analysis of the limiting distribution of the number of clumps of palindromes where clump is defined as the overlapping occurrence of palindromes. Using the Chen–Stein method, it is shown in this paper that the limiting distribution, under suitable conditions and a type of heterogeneous sequence, is the Poisson distribution. Moreover, error bounds and the rate of convergence are derived in terms of total variation distance between two probability distributions.