Unified Concept of Bottleneck

The term `bottleneck` has been extensively used in operations management literature. Management paradigms like the Theory of Constraints focus on the identification and exploitation of bottlenecks. Yet, we show that the term has not been rigorously defined. We provide a classification of bottleneck definitions available in literature and discuss several myths associated with the concept of bottleneck. The apparent diversity of definitions raises the question whether it is possible to have a single bottleneck definition which has as much applicability in high variety job shops as in mass production environments. The key to the formulation of an unified concept of bottleneck lies in relating the concept of bottleneck to the concept of shadow price of resources. We propose an universally applicable bottleneck definition based on the concept of average shadow price. We discuss the procedure for determination of bottleneck values for diverse production environments. The Law of Diminishing Returns is shown to be a sufficient but not necessary condition for the equivalence of the average and the marginal shadow price. The equivalence of these two prices is proved for several environments. Bottleneck identification is the first step in resource acquisition decisions faced by managers. The definition of bottleneck presented in the paper has the potential to not only reduce ambiguity regarding the meaning of the term but also open a new window to the formulation and analysis of a rich set of problems faced by managers.

Sinatra Living: Facilities and Equipment

This document, labeled as project document 3.4 Facilities and Equipment, contains a description of various facilities and equipment that can/need to be used in the Las Vegas area for the fabrication and building phase of the project

Environmental actions to reduce household ecological footprints

This paper presents the ideas of UK householders on how to reduce their Ecological Footprint (EF) after applying a tool called 'EcoCal', which assesses the environmental impacts of households by measuring footprints arising from Transport, Energy, Shopping, House and Garden, Water and Waste. Analysis of the EcoCal results of nearly 700 adult Open University (OU) student households showed that transport and energy impacts are the biggest contributors to the household footprint. Reducing these impacts poses the greatest challenge to achieving a globally sustainable household EF of approximately 0.5 hectares per person. Analysis of the ideas that the OU students were prepared to consider to reduce their household EF revealed a variety of technical and behavioural changes. However, in the context of their own household, the OU students identified several constraints on the implementation of their environmental action plans. Despite such constraints, many of the students instigated changes that helped to make their households more sustainable

Guidance on Stimulus Materials

PACHELBEL WP4 “Stimulus Materials” uses findings from WP3 (Policy Assumptions) and from additional sources to prepare stimulus materials for the group-based process “STAVE” implemented in WP5. The output was material to inform and stimulate the group-based process. The material was of two types: a set of questionnaires common to all partners (EVOC/CAPA/SIMI questionnaires), and material that is issue-specific and individually produced for each country. EVOC/CAPA/SIMI short questionnaires serve as a comparative tool between countries, giving insight on the social construction of “sustainable consumption” across the PACHELBEL population. Partners asked participants to fill out the set individually at the first meeting of the STAVE group, results were then analyzed and data were fed back for discussion by group participants at their second meeting. A “re-test” was then conducted at the third of three group meetings. The present report details the representations revealed through this methodology – but moreover the impact of applying such a technique in STAVE groups in France, Germany, Romania, Spain, Sweden and the UK (where the methodology was slightly altered). The issue-and-country-specific material consists of an informative simulated newspaper article on the particular issue addressed in a given STAVE process, and/or other materials (for example, humorous drawings). The report details how this material was developed, and the experience of applying these stimulus materials in each country. On this basis, guidance for future STAVE processes is offered. Foremost among observations is that PACHELBEL stimulus materials serve a purpose that is distinct from that of “group exercises” as developed in WP5. The materials contributing to the formation of a group identity, a reflexive group norm, and a shared information basis. As such, stimulus materials prepare the group for a cooperative investigative process

An application of a cocitation-analysis method to find further research possibilities on the area of scheduling problems

In this article we will give firstly a classification scheme of scheduling problems and their solving methods. The main aspects under examination are the following: machine and secondary resources, constraints, objective functions, uncertainty, mathematical models and adapted solution methods. In a second part, based on this scheme, we will examine a corpus of 60 main articles (1015 citation links were recorded in total) in scheduling literature from 1977 to 2009. The main purpose is to discover the underlying themes within the literature and to examine how they have evolved. To identify documents likely to be closely related, we are going to use the cocitation-based method of Greene et al. (2008). Our aim is to build a base of articles in order to extract the much developed research themes and find the less examined ones as well, and then try to discuss the reasons of the poorly investigation of some areas

Main Street Revitalization: Woonsocket, RI

A healthy environment that utilizes local urban ecologies will positively impact the health and well being of the community. It is important to create an environment that will foster understanding and inspire learning about native plants and animals, how to care for them, and how to protect them

Renewable Energy Options among Rural Households in Haryana and Himachal Pradesh: An Overview

In developing countries the energy problems are both widespread and serious. Lack of access to sufficient and sustainable supplies of energy impacts around 90% of the population of many developing countries. People are compelled to live without regular and good quality electricity supply. The rural population remains dependent on fuels such as animal dung, crop residues, fuel wood and charcoal to cook their daily meals. Without efficient, clean energy, people are undermined in their efforts to engage effectively in productive activities and improve their quality of life (Barnes and Floor, 1996). India is home to the largest rural population in the world with approx. 68.84% of the total population residing in rural areas (Census, 2011). In order to contribute to the overall development in India, access to modern energy and cleaner fuel for rural households is important. There is a need to bridge the access gap by expanding energy systems to meet the energy requirements of the fast growing population and mitigate the threat of climate change. The best possible solution to the energy poverty challenges lies in the shift towards sustainable energy technologies. In the present scenario, the uncontrollable increase in use of non-renewable energies such as fossil fuel, oil, natural gas has led to fluctuation of demand and supply. This negative energy balance for decades has forced India to purchase energy from other countries to fulfill the needs of the entire country. Hence, energy access is an important component of poverty alleviation and an indispensable element of sustainable human development. Government of India has initiated numerous development programmes, focusing on providing sustainable energy solutions to rural communities often deprived of clean and uninterrupted energy supply for their daily energy requirements. The study entitled ‘Renewable Energy Options among Rural Households\u27 was conducted in Haryana and Himachal Pradesh states. The outcomes of the study provide a roadmap for future programmes promoting the use of clean, efficient and modern energy technologies, to be implemented more effectively. Findings would further benefit the primary and secondary key stakeholders involved in research and development, formulation of policies and regulations, promoting sale and purchase and provide financial assistance to future energy programmes meant to popularize the use of Renewable Energy Technologies

Resource-constrained project scheduling.

Abstract: Resource-constrained project scheduling involves the scheduling of project activities subject to precedence and resource constraints in order to meet the objective(s) in the best possible way. The area covers a wide variety of problem types. The objective of this paper is to provide a survey of what we believe are important recent in the area . Our main focus will be on the recent progress made in and the encouraging computational experience gained with the use of optimal solution procedures for the basic resource-constrained project scheduling problem (RCPSP) and important extensions. The RCPSP involves the scheduling of a project its duration subject to zero-lag finish-start precedence constraints of the PERT/CPM type and constant availability constraints on the required set of renewable resources. We discuss recent striking advances in dealing with this problem using a new depth-first branch-and-bound procedure, elaborating on the effective and efficient branching scheme, bounding calculations and dominance rules, and discuss the potential of using truncated branch-and-bound. We derive a set of conclusions from the research on optimal solution procedures for the basis RCPSP and subsequently illustrate how effective and efficient branching rules and several of the strong dominance and bounding arguments can be extended to a rich and realistic variety of related problems. The preemptive resource-constrained project scheduling problem (PRCPSP) relaxes the nonpreemption condition of the RCPSP, thus allowing activities to be interrupted at integer points in time and resumed later without additional penalty cost. The generalized resource-constrained project scheduling (GRCPSP) extends the RCPSP to the case of precedence diagramming type of precedence constraints (minimal finish-start, start-start, start-finish, finish-finish precedence relations), activity ready times, deadlines and variable resource availability's. The resource-constrained project scheduling problem with generalized precedence relations (RCPSP-GPR) allows for start-start, finish-start and finish-finish constraints with minimal and maximal time lags. The MAX-NPV problem aims at scheduling project activities in order to maximize the net present value of the project in the absence of resource constraints. The resource-constrained project scheduling problem with discounted cash flows (RCPSP-DC) aims at the same non-regular objective in the presence of resource constraints. The resource availability cost problem (RACP) aims at determining the cheapest resource availability amounts for which a feasible solution exists that does not violate the project deadline. In the discrete time/cost trade-off problem (DTCTP) the duration of an activity is a discrete, non-increasing function of the amount of a single nonrenewable resource committed to it. In the discrete time/resource trade-off problem (DTRTP) the duration of an activity is a discrete, non-increasing function of the amount of a single renewable resource. Each activity must then be scheduled in one of its possible execution modes. In addition to time/resource trade-offs, the multi-mode project scheduling problem (MRCPSP) allows for resource/resource trade-offs and constraints on renewable, nonrenewable and doubly-constrained resources. We report on recent computational results and end with overall conclusions and suggestions for future research.Scheduling; Optimal;

Optimal Configuration and Energy Scheduling Algorithm for an Off-Grid Hybrid Microgrid

Off-grid hybrid microgrid which combines power sources from different technologies based on the availability of such resources and the economic/environmental considerations is gaining global interest due to the unreliable nature of conventional power systems. This research seeks to obtain an optimal configuration and develop a simple energy scheduling algorithm for a modern market using PV/Battery storage/Diesel generator technologies. HOMER software was used in obtaining the optimal configuration and economic/environmental analysis. The development of the scheduling algorithm was done based on the concept of energy flow in an off-grid hybrid microgrid using MATLAB software. An estimated load of 389.79 kW and average daily solar irradiance of 164.09W/m2 was recorded for the study site. The simulation results yielded Net Present Cost (NPC) of $6,405,234.36 and$0.2414 Cost of Energy (COE). A Greenhouse Gas (GHG) emission reduction of 42% was recorded for an off-grid system with solar renewable source. These clearly indicate that the use of optimized hybrid electrical energy resources with simple scheduling could greatly reduce both operational cost and environmental pollution