Proxy Wars

Proxy wars are a key pattern of political conflict and interstate competition. Rather than resorting to direct conflicts, which are costly and entail a higher level of uncertainty, governments may opt for proxy wars, which may last longer, but are less costly and render them more immune to exogenous shocks. We start with the modeling of a direct war with two players where a static equilibrium may be neither realizable nor sustainable in the long run. Then, we offer a model of proxy war where the proposed equilibria are realizable, but not always sustainable in the long run. The consolidation level of the double principal-agent relationship predicts the continuation of conflict and thus the emergence of peace

Economics of robots and automation in field crop production

This study reviewed research published after 1990 on the economics of agricultural mechatronic automation and robotics, and identified research gaps. A systematic search was conducted from the following databases: ScienceDirect, Business Source Complete, Wiley, Emerald, CAB Abstract, Greenfile, Food Science Source and AgEcon Search. This identified 4817 documents. The screening of abstracts narrowed the range to a dataset of 119 full text documents. After eligibility assessment, 18 studies were subjected to a qualitative analysis, with ten focused on automation of specific horticultural operations and eight related to autonomous agricultural equipment. All of the studies found some scenarios in which automation and robotic technologies were profitable. Most studies employed partial budgeting considering only costs and revenues directly changed by the introduction of automation or robotics and assuming everything else constant. None examined cropping system changes, or regional and national impacts on markets, trade and labour demand. The review identified a need for in-depth research on the economic implications of the technology. Most of the studies reviewed estimated economic implications assuming that technology design parameters were achieved and/or based on data from prototypes. Data are needed on the benefits and problems with using automation and robotics on farm. All of the studies reviewed were in the context of agriculture in developed countries, but many of the world’s most pressing agricultural problems are in the developing world. Economic and social research is needed to understand those developing country problems, and guide the engineers and scientists creating automation and robotic solutions

On the Number of Iterations for Dantzig-Wolfe Optimization and Packing-Covering Approximation Algorithms

We give a lower bound on the iteration complexity of a natural class of Lagrangean-relaxation algorithms for approximately solving packing/covering linear programs. We show that, given an input with $m$ random 0/1-constraints on $n$ variables, with high probability, any such algorithm requires $\Omega(\rho \log(m)/\epsilon^2)$ iterations to compute a $(1+\epsilon)$-approximate solution, where $\rho$ is the width of the input. The bound is tight for a range of the parameters $(m,n,\rho,\epsilon)$. The algorithms in the class include Dantzig-Wolfe decomposition, Benders' decomposition, Lagrangean relaxation as developed by Held and Karp [1971] for lower-bounding TSP, and many others (e.g. by Plotkin, Shmoys, and Tardos [1988] and Grigoriadis and Khachiyan [1996]). To prove the bound, we use a discrepancy argument to show an analogous lower bound on the support size of $(1+\epsilon)$-approximate mixed strategies for random two-player zero-sum 0/1-matrix games

Creating sustainable value through food waste management: does retail customer value proposition matter?

Purpose This research aims to explore retail managers' views on how food waste (FW) management activities contribute to sustainable value creation and how the customer value proposition (CVP) for a given food retailer interacts with their approaches to FW management. Design/methodology/approach A three-stage exploratory qualitative approach to data collection and analysis was adopted, involving in-depth interviews with retail managers, documentary analysis of multiple years of relevant corporate reports and email validation by seven major UK grocery retailers. Thematic content analysis supplemented by word similarity cluster analysis, two-step cluster analysis and crisp-set qualitative comparative analysis was undertaken. Findings FW management practices have been seen by retail managers to contribute to all forms of sustainable value creation, as waste reduction minimises environmental impact, saves costs and/or serves social needs, whilst economic value creation lies at the heart of retail FW management. However, retail operations are also framed by CVP and size of a retailer that enable or inhibit the adoption of certain FW management practices. Low-price retailers were more likely to adopt practices enabling them to save costs. Complicated cost-incurring solutions to FW were more likely to be adopted by retailers associated with larger size, high quality and a range of services. Originality/value This study is the first of its kind to empirically explore retail managers' perception of sustainable value creation through FW management activities and to provide empirical evidence of the linkages between retail CVP and sustainable value creation in the context of retail FW management

An overview of reliability assessment and control for design of civil engineering structures

Random variations, whether they occur in the input signal or the system parameters, are phenomena that occur in nearly all engineering systems of interest. As a result, nondeterministic modeling techniques must somehow account for these variations to ensure validity of the solution. As might be expected, this is a difficult proposition and the focus of many current research efforts. Controlling seismically excited structures is one pertinent application of nondeterministic analysis and is the subject of the work presented herein. This overview paper is organized into two sections. First, techniques to assess system reliability, in a context familiar to civil engineers, are discussed. Second, and as a consequence of the first, active control methods that ensure good performance in this random environment are presented. It is the hope of the authors that these discussions will ignite further interest in the area of reliability assessment and design of controlled civil engineering structures

A Greek validation study of the Multiple Sclerosis Work Difficulties Questionnaire-23

The Multiple Sclerosis Work Difficulties Questionnaire-23 (MSWDQ-23) is a self-reportinstrument developed to assess barriers faced by People with Multiple Sclerosis (PwMS) in theworkplace. The aim of this study was to explore the psychometric properties of the Greek versionof the MSWDQ-23. The study sample consisted of 196 PwMS, all currently working in part- orfull-time jobs. Participants underwent clinical examination and cognitive screening with the BriefInternational Cognitive Assessment for Multiple Sclerosis (BICAMS) and completed self-reportmeasures of fatigue, psychological functioning, and quality of life, along with the MSWDQ-23questionnaire. Confirmatory Factor Analysis (CFA) was performed, and goodness-of-fit measureswere used to evaluate construct validity. Convergent validity was checked by correlating MSWDQ-23scores with study measures. Cronbach’s alpha value was produced to assess internal consistency.CFA yielded a model with a fair fit confirming the three-factor structure of the instrument. Higherwork difficulties were associated with higher Expanded Disability Status Scale (EDSS) scores, poorercognitive function, more fatigue, stress, anxiety, and depression, and poorer health status, supportingthe convergent validity of MSWDQ-23. Internal consistency (Cronbach’s alpha = 0.94) and test–retest reliability (ICC = 0.996, 95%, CI = 0.990–0.998) were excellent. The Greek MSWDQ-23 can beconsidered a valid patient-reported outcome measure and can be used in interventions aiming toimprove the vocational status of PwMS

Athens by Sound

Architecture is not only that which is built. Architecture is made up of different aspects, both material and immaterial. The atmosphere, the sounds, the smells, the possibility of interaction between human bodies: these all constitute characteristics of space, characteristics that are assuming an increasing importance within architectural research worldwide. Within this field of thought about “Architecture Beyond Building”, we focus on one particular non-material spatial phenomenon that lies ‘beyond the built’: sound. We have created, thus, an interactive sonic map of Athens, which presents, in an unexpected way, fragments of the atmosphere of the city. What would a non-visual map look like? What would it feel like if you wandered within a forest of headphones, playing sounds from different places in Athens? How would it feel if you found yourself in a ‘map’ that only appeared when you walked in it? What would it be like if the map only appeared when you invited one more person to be with you? The Greek pavilion addresses these questions through an atmospheric interactive ‘game’, presenting fragments of sounds and visual sequences of Athens. The visitor recreates the space around him through his own presence and movement. The map appears only where he walks, and/or when he invites one more person to sit next to him. The bodies of the visitors react with one another and with the space itself, creating a dynamic, changing field. This walk in the pavilion takes you “out there”, through invisible Athens. The pavilion brings forth the aspects of architecture that are ‘beyond the material’: the ‘beyond the built’, the almost unreachable, elusive aspects of space, such as sound, non-visual senses, atmosphere. It challenges, thus, the limits of architecture, the limits of what can be mapped and re-located and what cannot. An edited collection by A. Karandinou, C. Achtypi, S. Giamarelos, including texts by: Ιntothepill, Katie Lloyd Thomas, Martin Parker, Panayiotis Tournikiotis, Mark Wigley, Dorian Wiszniewski, Leslie Kavanaugh, Stephen Cairns, Jonathan Hill, Vassilis Ganiatsas, Anastasios Kotsiopoulos, Constance Classen, Stavros Stavrides, Ole Bouman, William Mitchell, Richard Coyne, Neil Spiller, Kas Oosterhuis, Nora Schueler, Zissis Kotionis, Stelarc, Andreas Angelidakis, Aristide Antonas, Slavoj Žižek, Nikolaos Laskaris, Argyris Rokas, Andreas Kourkoulas, John Peponis, Yorgos Ioannou, Yorgos Tzirtzilakis, Konstantinos Vita, Dionyssis Kapsalis, United Visual Artists, Platon Rivellis, and Dimitris Filippidis. Contributors to the Greek National Participation to the 11th International Architecture Exhibition La Biennale di Venezia "Out there. Architecture beyond building" (2008) Organised by: Hellenic Ministry of Culture [yppo.gr] General Directorate of Modern Culture Directorate of Visual Arts Department for the Promotion of Contemporary Art Curators: Anastasia Karandinou Christina Achtypi Stylianos Giamarelos Video works by Intothepill net [intothepill.net] Artists: Yiannis Grigoriadis Yiannis Isidorou Lina Theodorou Sound Recording / Sound Design Dimitris Miyakis [movement.gr] Vangelis Lympouridis Exhibition Graphics / Catalogue Design Company [company-london.com] Design and Implementation of interactive environment 2monochannels [2monochannels.com] Audiovisual and interactive systems design / acoustic design / construction supervision Iraklis Lampropoulos Giorgos Lampropoulos Software programming Vassilis Boukis Electronic subsystem design Michail Kritsotakis Electrical Design Giorgos Satolias Interconnection of interactive elements Vangelis Lympouridis [inter-axions.com] Dimitris Miyakis Light design L+DG lighting architects [lightingdg.com] Thomas Gravanis Christina Frangeti Construction Gavrilos Michalis [gavrilos.gr] Digital printing Polichromo [polichromo.com] Translations Rachel Howard Nikos Masourides Catalogue photographs Intothepill – Internet video platform Catalogue published by futura publications Marketing communication Chryssa Vrouzi Communication associate Katerina Stamidi Photographer Cathy Cunliffe [cathycunliffeΑΤgmail.com] For their financial and material support for the Greek participation at the 11th International Exhibition of Architecture, La Biennale di Venezia, we express our deepest thanks to the sponsors: Alexander S. Onassis Public Benefit Foundation [onassis.gr] Akzonobel [akzonobel.com] Carteco - Architectural Materials & Design [carteco.gr] L+DG Lighting Architects [lightingdg.com] Plaisio [plaisio.gr] Polichromo Advertising Applications [polichromo.com] iGuzzini illuminazione [iguzzini.com] Diathlasis Architectural Lighting [diathlasis.gr