Branch and price solution approach for order acceptance and capacity planning in make -to -order operations

The increasing emphasis on mass customization, shortened product lifecycles, synchronized supply chains, when coupled with advances in information system, is driving most firms towards make-to-order (MTO) operations. Increasing global competition, lower profit margins, and higher customer expectations force the MTO firms to plan its capacity by managing the effective demand. The goal of this research was to maximize the operational profits of a make-to-order operation by selectively accepting incoming customer orders and simultaneously allocating capacity for them at the sales stage. ^ For integrating the two decisions, a Mixed-Integer Linear Program (MILP) was formulated which can aid an operations manager in an MTO environment to select a set of potential customer orders such that all the selected orders are fulfilled by their deadline. The proposed model combines order acceptance/rejection decision with detailed scheduling. Experiments with the formulation indicate that for larger problem sizes, the computational time required to determine an optimal solution is prohibitive. This formulation inherits a block diagonal structure, and can be decomposed into one or more sub-problems (i.e. one sub-problem for each customer order) and a master problem by applying Dantzig-Wolfe’s decomposition principles. To efficiently solve the original MILP, an exact Branch-and-Price algorithm was successfully developed. Various approximation algorithms were developed to further improve the runtime. Experiments conducted unequivocally show the efficiency of these algorithms compared to a commercial optimization solver.^ The existing literature addresses the static order acceptance problem for a single machine environment having regular capacity with an objective to maximize profits and a penalty for tardiness. This dissertation has solved the order acceptance and capacity planning problem for a job shop environment with multiple resources. Both regular and overtime resources is considered. ^ The Branch-and-Price algorithms developed in this dissertation are faster and can be incorporated in a decision support system which can be used on a daily basis to help make intelligent decisions in a MTO operation.^

Consolidating Security and Development in Colombia: Lessons for Peru and Panama

Colombia's increasingly effective efforts to mitigate the power of the FARC and other illegitimately armed groups in the country can offer important lessons for the Peruvian government as it strives to prevent a resurgence of Sendero Luminoso and other illegal non-state actors. Both countries share certain particular challenges: deep economic, social, and in the case of Peru ethnic divisions, the presence of and/or the effects of violent insurgencies, a large-scale narcotics production and trafficking, and a history of weak state presence in large tracts of isolated and scarcely-populated areas. Important differences exist, however in the nature of the insurgencies in the two countries, the government response to them and the nature of government and society that affects the applicability of Colombia's experience to Peru. The security threat to Panama from drug trafficking and Colombian insurgents --often a linked phenomenon-- are in many ways different from the drug/insurgent factor in Colombia itself and in Peru, although there are similar variables. Unlike the Colombian and Peruvian cases, the security threat in Panama is not directed against the state, there are no domestic elements seeking to overthrow the government -- as the case of the FARC and Sendero Luminoso, security problems have not spilled over from rural to urban areas in Panama, and there is no ideological component at play in driving the threat. Nor is drug cultivation a major factor in Panama as it is in Colombia and Peru. The key variable that is shared among all three cases is the threat of extra-state actors controlling remote rural areas or small towns where state presence is minimal. The central lesson learned from Colombia is the need to define and then address the key problem of a "sovereignity gap," lack of legitimate state presence in many part of the country. Colombia's success in broadening the presence of the national government between 2002 and the presence is owed to many factors, including an effective national strategy, improvements in the armed forces and police, political will on the part of government for a sustained effort, citizen buy-in to the national strategy, including the resolve of the elite to pay more in taxes to bring change about, and the adoption of a sequenced approach to consolidated development in conflicted areas. Control of territory and effective state presence improved citizen security, strengthened confidence in democracy and the legitimate state, promoted economic development, and helped mitigate the effect of illegal drugs. Peru can benefit from the Colombian experience especially in terms of the importance of legitimate state authority, improved institutions, gaining the support of local citizens, and furthering development to wean communities away from drugs. State coordinated "integration" efforts in Peru as practiced in Colombia have the potential for success if properly calibrated to Peruvian reality, coordinated within government, and provided with sufficient resources. Peru's traditionally weak political institutions and lack of public confidence in the state in many areas of the country must be overcome if this effort is to be successful.

Foreign Language Education in Colombia: A Qualitative Study of Escuela Nueva

Since 2004 the Colombian Ministry of Education has been implementing the Programa Nacional de Bilingüismo (PNB) with the goal of having bilingual high school graduates in English and Spanish by 2019. However, implementation of the PNB has been criticized by English Language Teaching (ELT) specialists in the country who say, among other things, that the PNB introduced a discourse associated exclusively with bilingualism in English and Spanish. This study analyzed interviews with 15 participants of a public school of the Colombian Escuela Nueva, a successful model of community-based education that has begun a process of internationalization, regarding the participants’ perceptions of foreign language education and the policies of the PNB. Six students, five teachers, and four administrators were each interviewed twice using semi-structured interviews. To offer a critique of the PNB, this study tried to determine to what extent the school implemented the elements of Responsible ELT, a model developed by the researcher incorporating the concepts of hegemony of English, critical language-policy research, and resistance in ELT. Findings included the following: (a) students and teachers saw English as the universal language whereas most administrators saw English imposed due to political and economic reasons; (b) some teachers misinterpreted the 1994 General Law of Education mandating the teaching of a foreign language as a law mandating English; and (c) some teachers and administrators saw the PNB’s adoption of competence standards based on the Common European Framework of Reference for languages as beneficial whereas others saw it as arbitrary. Conclusions derived from this study of this Escuela Nueva school were: (a) most participants found the goal of the PNB unrealistic; (b) most teachers and administrators saw the policies of the PNB as top-down policies without assessment or continuity; and (c) teachers and administrators mentioned a disarticulation between elementary and high school ELT policies that may be discouraging students in public schools from learning English. Thus, this study suggests that the policies of the PNB may be contributing to English becoming a gatekeeper for higher education and employment thereby becoming a tool for sustaining inequality in Colombia.

Hospital discharge planning in the provision of food and nutrition services for older adults post discharge

This descriptive study examined whether discharge planning ensures that food and nutrition services are provided to older adults following hospital discharge. The questionnaire was distributed to discharge planning professionals in 11 South Florida hospitals. Of the 84 respondents (88% response rate), most were female nurse case managers. Almost all reported job barriers including excessive patient loads, too many responsibilities, and limited community services. While physicians, registered nurses, social workers, physical therapists, were deemed "very important" in discharge planning,registered dietitians were not, and almost half consulted them infrequently, if at all. Over 84% said nutrition-related medical conditions/factors, "strongly influenced" discharge planning. Many did not have adequate information about nutrition-related community resources, eg, home delivered meals, food stamps, outpatient registered dietitians. Therewere no universal approaches in meeting the nutrition needs in 6 case scenarios. More communication among community services and hospitals is needed.

Branch and Price Solution Approach for Order Acceptance and Capacity Planning in Make-to-Order Operations

The increasing emphasis on mass customization, shortened product lifecycles, synchronized supply chains, when coupled with advances in information system, is driving most firms towards make-to-order (MTO) operations. Increasing global competition, lower profit margins, and higher customer expectations force the MTO firms to plan its capacity by managing the effective demand. The goal of this research was to maximize the operational profits of a make-to-order operation by selectively accepting incoming customer orders and simultaneously allocating capacity for them at the sales stage. For integrating the two decisions, a Mixed-Integer Linear Program (MILP) was formulated which can aid an operations manager in an MTO environment to select a set of potential customer orders such that all the selected orders are fulfilled by their deadline. The proposed model combines order acceptance/rejection decision with detailed scheduling. Experiments with the formulation indicate that for larger problem sizes, the computational time required to determine an optimal solution is prohibitive. This formulation inherits a block diagonal structure, and can be decomposed into one or more sub-problems (i.e. one sub-problem for each customer order) and a master problem by applying Dantzig-Wolfe’s decomposition principles. To efficiently solve the original MILP, an exact Branch-and-Price algorithm was successfully developed. Various approximation algorithms were developed to further improve the runtime. Experiments conducted unequivocally show the efficiency of these algorithms compared to a commercial optimization solver. The existing literature addresses the static order acceptance problem for a single machine environment having regular capacity with an objective to maximize profits and a penalty for tardiness. This dissertation has solved the order acceptance and capacity planning problem for a job shop environment with multiple resources. Both regular and overtime resources is considered. The Branch-and-Price algorithms developed in this dissertation are faster and can be incorporated in a decision support system which can be used on a daily basis to help make intelligent decisions in a MTO operation.

The Politico-Economics of Electricity Planning in Developing Countries : A Case Study of Ghana

The first author would like to thank the University of Aberdeen and the Henderson Economics Research Fund for funding his PhD studies in the period 2011-2014 which formed the basis for the research presented in this paper.

How effective are heuristic solutions for electricity planning in developing countries

Acknowledgement The first author would like to acknowledge the University of Aberdeen and the Henderson Economics Research Fund for funding his PhD studies in the period 2011-2014 which formed the basis for the research presented in this paper. The first author would also like to acknowledge the Macaulay Development Trust which funds his postdoctoral fellowship with The James Hutton Institute, Aberdeen, Scotland. The authors thank two anonymous referees for valuable comments and suggestions on earlier versions of this paper. All usual caveats apply

Development and testing of an analytical framework for immunization program planning in Canada

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Prioritizing tropical habitats for long-distance migratory songbirds: an assessment of habitat quality at a stopover site in Colombia

Long-distance migratory birds are declining globally and migration has been identified as the primary source of mortality in this group. Despite this, our lack of knowledge of habitat use and quality at stopovers, i.e., sites where the energy for migration is accumulated, remains a barrier to designing appropriate conservation measures, especially in tropical regions. There is therefore an urgent need to assess stopover habitat quality and concurrently identify efficient and cost-effective methods for doing so. Given that fuel deposition rates directly influence stopover duration, departure fuel load, and subsequent speed of migration, they are expected to provide a direct measure of habitat quality and have the advantage of being measurable through body-mass changes. Here, we examined seven potential indicators of quality, including body-mass change, for two ecologically distinct Neotropical migratory landbirds on stopover in shade-coffee plantations and tropical humid premontane forest during spring migration in Colombia: (1) rate of body-mass change; (2) foraging rate; (3) recapture rate; (4) density; (5) flock size; (6) age and sex ratios; and (7) body-mass distribution. We found higher rates of mass change in premontane forest than in shade-coffee in Tennessee Warbler Oreothlypis peregrina, a difference that was mirrored in higher densities and body masses in forest. In Gray-cheeked Thrush Catharus minimus, a lack of recaptures in shade-coffee and higher densities in forest, also suggested that forest provided superior fueling conditions. For a reliable assessment of habitat quality, we therefore recommend using a suite of indicators, taking into account each species’ ecology and methodological considerations. Our results also imply that birds stopping over in lower quality habitats may spend a longer time migrating and require more stopovers, potentially leading to important carryover effects on reproductive fitness. Evaluating habitat quality is therefore imperative prior to defining the conservation value of newly identified stopover regions.

TPEA good practice guide: lessons for cross-border MSP from transboundary planning in the European Atlantic

This Good Practice Guide is the outcome of a project co-funded by the European Commission (DG Mare) called Transboundary Planning in the European Atlantic (TPEA), which ran from December 2012 to May 2014. The aim of the project was to demonstrate approaches to transboundary maritime spatial planning (MSP) in the European Atlantic region. This is one of a series of projects exploring the opportunities and challenges of carrying out cross-border MSP in Europe’s regional seas, making connections with integrated coastal management (ICM). TPEA focused on two pilot areas: one involving Portugal and Spain and the other Ireland and the United Kingdom. Despite distinct identities in the region relating to different traditions of planning and stages of MSP implementation, TPEA worked towards a commonly-agreed approach to transboundary MSP and developed principles of cross-border working which it is hoped will be of wider benefit. This guide presents these principles, illustrated with examples from the TPEA project.

Development and testing of an analytical framework for immunization program planning in Canada

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Housing and Planning in London under the Conservative Government: Spatial impacts, social polarisation, sustainable development and social justice

This paper will be based on my continuing research on planning and housing development in London. It will focus on the proposals in the Government’s Housing and Planning Bill, which are likely to be enacted in Spring 2016. It will review the evidence of potential spatial impacts in terms of the supply of existing affordable homes and the location and affordability of new supply. This will be related to a review of the alternative development options for London’s growth in the context of the Mayor of London’s draft 2050 Infrastructure Plan. The paper will analyse the potential impact of new Government policy and legislation on whether London’s housing requirements can be delivered in accordance with the objectives of sustainable planning and social justice, and will also consider the constraints on the ability of the new Mayor of London, to be elected in May 2016 to achieve manifesto commitments.

Applying the security-development nexus on the ground: Land restitution in Colombia

The general consensus on the security-development nexus is that both are key to achieving sustainable peace in war-torn societies. However, this debate has largely taken place among international actors, with little empirical evidence about how security and development relate to each other or are even considered by local actors. The current paper applies the security-development nexus to the case of land restitution in Colombia. Following decades of internal armed conflict, in 2012 the national government passed sweeping land restitution legislation amid on-going violence. Through in-depth interviews and focus groups with multiple actors involved in this process, ranging from international organizations to national government units, from regional institutions to local communities, the paper analyses the objectives, impact, challenges and opportunities for land restitution related to security and development. Undermining peacebuilding, a lack of coherence in the integration of security and development priorities limits the extent to which either supports, or is promoted by, land restitution efforts in Colombia. The paper concludes with reflections on how the security-development nexus may promote peacebuilding amid on-going conflict.