56,512 research outputs found

    GraphCombEx: A Software Tool for Exploration of Combinatorial Optimisation Properties of Large Graphs

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    We present a prototype of a software tool for exploration of multiple combinatorial optimisation problems in large real-world and synthetic complex networks. Our tool, called GraphCombEx (an acronym of Graph Combinatorial Explorer), provides a unified framework for scalable computation and presentation of high-quality suboptimal solutions and bounds for a number of widely studied combinatorial optimisation problems. Efficient representation and applicability to large-scale graphs and complex networks are particularly considered in its design. The problems currently supported include maximum clique, graph colouring, maximum independent set, minimum vertex clique covering, minimum dominating set, as well as the longest simple cycle problem. Suboptimal solutions and intervals for optimal objective values are estimated using scalable heuristics. The tool is designed with extensibility in mind, with the view of further problems and both new fast and high-performance heuristics to be added in the future. GraphCombEx has already been successfully used as a support tool in a number of recent research studies using combinatorial optimisation to analyse complex networks, indicating its promise as a research software tool

    Two-echelon freight transport optimisation: unifying concepts via a systematic review

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    Multi-echelon distribution schemes are one of the most common strategies adopted by the transport companies in an aim of cost reduction, but their identification in scientific literature is not always easy due to a lack of unification. This paper presents the main concepts of two-echelon distribution via a systematic review, in the specific a meta-narrative analysis, in order to identify and unify the main concepts, issues and methods that can be helpful for scientists and transport practitioners. The problem of system cost optimisation in two-echelon freight transport systems is defined. Moreover, the main variants are synthetically presented and discussed. Finally, future research directions are proposed.location-routing problems, multi-echelon distribution, cross-docking, combinatorial optimisation, systematic review.

    Scheduling commercial advertisements for television

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    The problem of scheduling the commercial advertisements in the television industry is investigated. Each advertiser client demands that the multiple airings of the same brand advertisement should be as spaced as possible over a given time period. Moreover, audience rating requests have to be taken into account in the scheduling. This is the first time this hard decision problem is dealt with in the literature. We design two mixed integer linear programming (MILP) models. Two constructive heuristics, local search procedures and simulated annealing (SA) approaches are also proposed. Extensive computational experiments, using several instances of various sizes, are performed. The results show that the proposed MILP model which represents the problem as a network flow obtains a larger number of optimal solutions and the best non-exact procedure is the one that uses SA

    How Educators Can Eradicate Disparities in School Discipline: A Briefing Paper on School-Based Interventions

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    The number of students issued suspensions in U.S. schools continues to be extremely high, resulting in thousands of students missing school every day. Simultaneously,disparities in school suspension continue to worsen, indicating that students in some groups are missing school far more often and disproportionately(particularly, boys, African American students, students with disabilities, and in some regions, Latino and American Indian students). These disparities are also true of referrals to law enforcement and school-based arrests nationwide. According to recent data collected by the Department of Education's Office for Civil Rights, students of color made up 75% of referrals to law enforcement and 79% of schoolbased arrests, even while students of color comprise 39% of the nation's public school population.Punitive school discipline matters tremendously to the educational opportunity of young people: New knowledge on school discipline shows that even a single suspension or a single referral to the juvenile court system increases the odds of low achievement and dropping out of school altogether. Moreover, research shows that schools and educators -- not just students themselves -- make a difference in how discipline is meted out

    Reflective visualization and verbalization of unconscious preference

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    A new method is presented, that can help a person become aware of his or her unconscious preferences, and convey them to others in the form of verbal explanation. The method combines the concepts of reflection, visualization, and verbalization. The method was tested in an experiment where the unconscious preferences of the subjects for various artworks were investigated. In the experiment, two lessons were learned. The first is that it helps the subjects become aware of their unconscious preferences to verbalize weak preferences as compared with strong preferences through discussion over preference diagrams. The second is that it is effective to introduce an adjustable factor into visualization to adapt to the differences in the subjects and to foster their mutual understanding.Comment: This will be submitted to KES Journa

    United Humanity: from "UN 2.0" to "UN 3.0" The conceptual model of the United Nations for the XXI century

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    The conceptual model of United Nations reform - "UN 3.0" includes the General Program of Action on UN Reform, consisting of two stages. The first stage for 2020-2025 envisages the transformation of the main organs of the UN - the General Assembly and the Security Council with measures to improve the effectiveness of the management system, address the "veto problem", problem of financing, improve staff work and administrative and financial control, strengthen UN media, improvement of work with the global civil society. The General Assembly is converted into the General All-Parliamentary Assembly of the UN. In the structure of the Assembly, the Council for Law is being established, which coordinates the activities of UN structures in the field of law. To coordinate the activities of the UN in the field of human rights and civil society, ethical issues, the General all-parliamentary Assembly creates the Council on ethics, human rights and civil society and transforms the Committee on information into the Council on public information and communication with civil society. The structure of the Council includes all UN media. The reform of the UN Security Council is carried out in three sub-stages. At the 1st sub-stage (2020-2021) the Security Council is transformed into the Council of Existential Security (CES). The membership of the CES is increased to 25 member countries, of which five countries have the right of the unconditional (absolute, eternal) veto: Great Britain, France, China, Russian Federation, USA. The General All-Parliamentary Assembly elects 15 new permanent members of the Council of Existential Security with the right of the conditional (limited) veto: Argentina, Australia, Brazil, Canada, Egypt, Germany, India, Indonesia, Italy, Mexico, South Africa, Nigeria, Pakistan , Turkey, Japan (if they fulfill the mandatory restrictive conditions). At this sub-stage, the CES elects also five non-permanent members with the right of a conditional (limited) veto when they meet the mandatory restrictive conditions, with a rotation period of 2 years from geographical regions (or regional unions): Africa, Latin America and the Caribbean, Asia and the Pacific Ocean (2 places), Eastern Europe. On the second sub-stage (2022-2023), subject to the effective activity of the CES of the enlarged composition and compliance with mandatory restrictive conditions, new permanent members of the "Existential Security Council" are elected with the right of a conditional (limited) veto: Iran, Spain, Poland, Saudi Arabia. Members of the CES may be regional unions, whose member countries are not represented in the CES, but still have one vote with the right of a conditional (limited) veto. Two essential levels of the veto: 1. Unconditional (absolute, eternal) veto is the historical right of veto of the five permanent members of the Council of Existential Security - Great Britain, China, Russia, USA, France; 2. Сonditional (limited) veto is the veto of other permanent and non-permanent members of the Council of Existential Security. The right of veto is a unique international school for the achievement of consensus, a school of high democracy for Humanity, a reliable guarantee of the viability of the UN structure. The Council for Existential Security centralises the management of the UN subsidiary bodies with the expansion of their security functions: the Military Staff Committee, the Counter-Terrorism Committee, the Committee for the Prevention of the Spread of Nuclear, Chemical and Biological Weapons, the Sanctions Committees and other committees. On the basis of the decision of the Council of Existential Security, the General All-Parliamentary Assembly creates permanent contingents of UN peacekeeping and counter-terrorism forces. In addition, two Centers are being created in the structure of the Council for Existential Security: the World Center for the Elimination of the Effects of Technogenic and Natural Disasters with branches on all continents and the World Center for the Analysis of Existential Risks and the Overall Security Strategy. The Center is developing the Programs of research and monitoring of global existential threats and risks. In order to increase the level of legitimacy and authority of the Secretary General of the United Nations, the Rules of procedure for elections to this post are changing. Each member country of the Council for Existential Security represents one of the most authoritative candidates for election to the post of Secretary General at the session of the General All-Parliamentary Assembly, with the possibility of nominating candidates from other countries, including those not members of the Council for Existential Security. Elections are held in two rounds during one day of the session of the Assembly. The Legal Committee of the UN General Assembly is developing a Program for the Reform of the Judicial System of the United Nations, which takes into account the proposals of the previous international discussion and determines the scope and terms of the reform of the courts. In accordance with the Program of Action on UN Reform for 2020-2025, reforms are under way in the structure of the Economic and Social Council. The central task of the reform is to strengthen the coordinating role of ECOSOC in the entire system of UN-related specialized agencies, funds and programs related to the Council. The key task of the UN reform is the solution of the financing problem. A unified "UN Open Budget "Solidarity XXI" is being created, including the financing of peacekeeping operations and other expenses. Each country, a member of the United Nations, lists in an established period, once a year, an Existential contribution - the Earth Tax. The Earth Tax for each UN member state is established on the basis of four scales of calculation: Scale I - for 5 permanent members of the Council of Existential Security, who have the right of absolute (absolute) veto; Scale II - for the permanent members of the SEB, who have the right to a conditional (limited) veto; Scale III - for non-permanent members of the SEB, who have the right to a conditional (limited) veto; Scale IV - for all other UN member countries. The program of action on UN reform includes a set of measures to ensure transparent work of the International Civil Service Commission with the involvement of the UN media. To strengthen control functions in the sphere of personnel policy, administrative and financial management, the General All-Parliamentary Assembly of the United Nations establishes the Permanent Commission on Ethics and Administrative and Financial Control. All members of the Commission, members of the Committees and auditors are independent in their activities from the leadership of the United Nations, its funds and programs. The General All-Parliamentary Assembly completes the first stage of the Program of Action on UN Reform in 2025 and, following an open discussion, introduces a single language of international communication - Esperanto and approves it as the official language of the United Nations. With a view to more effective work of the central UN governing bodies in the face of increasing existential threats and risks, reducing the current expenses for the maintenance of the central bodies of the UN, the Council for Existential Security and the General All-Parliamentary Assembly decide on the relocation of the UN headquarters to Iceland. The UN building complex in New York is transferred to preferential use of non-governmental organizations, which contribute to the implementation of the goals of the United Nations. At the second stage of the UN reform in the period 2026-2028, additional necessary transformations are being made in the UN system. At the end of the first stage of the reform, taking into account the reforms carried out by the main organs of the United Nations and the internal improvement of the work of all its structures, the United Nations Program of Action for the years 2026-2028 is being developed
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