An economic-statistical design of double sampling control chart

The double sampling (DS) chart can reduce the sample size when monitoring the process mean. In this study, Duncan's cost model was modified by adding the statistical constraints to develop the design model of DS chart for the optimization of design parameters—sample size, control limit coefficient, warning limit coefficient and sampling interval. A numerical example was provided to illustrate the use of this model. A sensitivity analysis of the effects of model parameters and statistical constraints on the optimal design of DS chart was also performed.     

Double vision: Insights about the origin and interpretation of multiple IRRs

The ability of a project's internal rate of return (IRR) to quantify its economic return has been questioned by many scholars over the past 60 years, most recently by Magni (2010 Magni, C.A. (2010) Average internal rate of return and investment decisions: a new perspective. The Engineering Economist, 55(2), 150–180. [Google Scholar], 2013 Magni, C.A. (2013) The internal rate of return approach and the AIRR paradigm: a refutation and a corroboration. The Engineering Economist, 58(2), 73–111. [Google Scholar]). Although IRR is a plausible—albeit imperfect—measure of a project's economic return when the cash flow stream is conventional, IRR can be an untenable measure of an unconventional project's economic return. The goal of this article is to identify a simple, intuitive explanation of IRR, one that can be applied to any cash flow pattern. To do this, the article shows how a project's IRR systematically changes when it first crosses from the conventional into the unconventional realm (i.e., a small cash outflow is appended to a conventional cash flow stream) and then as it becomes progressively more unconventional. This process reveals that the most robust economic interpretation of IRR—for both conventional and unconventional projects—is that a project's IRRs are external benchmarks that divide the set of all plausible discount rates into positive and negative net present value (NPV) ranges, rather than internally generated returns. Because it can be difficult to estimate a project's cost of capital with precision, this information can help guide the sensitivity analysis of a project.     

MICROCOMPUTER SOFTWARE COSTING LESS THAN $1000 FOR ECONOMIC AND MULTI-ATTRIBUTE DECISION ANALYSIS∗

Commodity price simulation is useful in many engineering economics applications, yet discrete approximations of the continuous stochastic processes used in modeling commodity prices are not always straightforward. This article describes the exact solution for discretely simulating the Schwartz and Smith (2000 Schwartz, E. and Smith, J. E. 2000. Short-term variations and long-term dynamics in commodity prices. Management Science, 46(7): 893–911. [Crossref], [Web of Science ®] , [Google Scholar]) two-factor model of commodity prices.     

A review of: “ENGINEERING ECONOMY, 4th. Ed.” By E. Paul DeGarmo The Macmillan Company 1967 532 pp. $10.95.

A risk measure, expected opportunity loss (EOL), is introduced to quantify the potential loss of making an incorrect choice in risk-based decision making. Different from Savage's (1951 Savage, L. J. 1951. The theory of statistical decision. Journal of the American Statistical Association, 46(253): 55–67. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) minimax regret principle, EOL can account for the unbounded continuous random outcomes of alternatives and decision makers’ acceptable risk. This article studies the effects of the forms of loss function, correlation among outcomes, and the acceptable risk on the ranking results by considering the loss function in the power form. The results show that the loss functions and the outcomes correlations can significantly influence the rankings of alternatives in risk-based decision making.     

Quantifizierung und Systematisierung der technischen und verhaltensbedingten Stromeinsparpotenziale der deutschen Privathaushalte

Electricity consumption in German households accounts for more than 10 % of energy-related CO₂ emissions. In spite of substantial improvements in, for example, the efficiency of household appliances, there is still a considerable electricity savings potential to be tapped in this sector. The possible contribution that the German residential sector can make to climate protection is correspondingly large. This paper aims to structure and quantify electricity savings potentials which could be exploited in German households either through investment measures or changed user behaviour. The total theoretical potential which can be tapped through the purchase of efficient household appliances and the replacement of electrical heaters and hot water generators (i.e. by encouraging investment) amounts to approx. 90 TWh/a. This corresponds to more than 60 % of the current electricity demand of all German households. By means of changed user behaviour, approx. 30 TWh of electricity could be saved according to our calculations. These results presented in this article were reached within the scope of the TRANSPOSE interdisciplinary research project (http://www.uni-muenster.de/Transpose/, the complete analysis can be downloaded at http://www.uni-muenster.de/imperia/md/content/transpose/publikationen/buerger_working_paper_3.pdf). This project is funded within the framework of the ‘Social-ecological Research’ programme of the German Federal Ministry for Education and Research.     

Discounting Indices Proposed for Capital Investment Evaluation: A Further Examination

A recent publication [2 Bernhard , Richard H. , “ A Comprehensive Comparison and Critique of Discounting Indices Proposed for Capital Investment Evaluation ,” The Engineering Economist , Volume 16 , Number 3 , Spring 1971 .[Taylor &; Francis Online] , [Google Scholar]] in this journal presented a comprehensive comparison and critique of discounting indices proposed for (i) the examination of whether a proposed independent project should be accepted and (ii) selection of a project from a set of mutually exclusive projects. The present paper examines procedures available in the literature of engineering and managerial economics and in practice for selecting projects from a given number of proposed capital investment projects, if a given capital constraint does not permit the undertaking of all proposed projects. It appears that the present state of the art is subject to much controversy and confusion. The ensuing presentation intends to rectify this situation. In addition, a procedure for the above selection problem is developed. Usage of this procedure is recommended for the many policy makers who are continually faced with the trade-off between elaborate methods on the one hand and cursory /approximations on the other.     

A review of: “APPLIED ECONOMIC ANALYSIS FOR TECHNOLOGISTS,ENGINEERS, AND MANAGERS ” BY MICHAEL S. BOWMAN Prentice-Hall,Inc., Upper Saddle River,New Jersey, 1999, xii + 561 pp., ISBN: 0-13-375932-6, List: $76.75.

In their recent paper Tang and Tang (2003 Tang, S. L. and Tang, H. J. 2003. The variable financial indicator IRR and the constant economic indicator NPV.. The Engineering Economist, Vol. 48(No. 1): pp. 69–78. [Taylor &; Francis Online] , [Google Scholar], pp. 69–78) revive a longstanding controversy—net present value (NPV) versus internal rate of return (IRR)—by characterizing the NPV as an economic indicator and the IRR as a financial one. The paper implies that this distinction justifies ranking financial alternatives by ranking their IRRs. In the current article, it is argued that the direct IRR ranking does not necessarily provide the same evaluation environment—and therefore a fair comparison—for each alternative involved, and that the incremental ranking approach is needed to remedy this shortcoming. The article also points out that Tang and Tang's numerical examples of simple projects with one sign change in their cash flow patterns do not address the problem of multiple IRRs, which consequently renders Tang and Tang's ranking approach dysfunctional. It is demonstrated that the concept of a true rate of return, substituting for the non-performing IRR and applied in conjunction with the incremental approach, provides an adequate tool for ranking mutually exclusive projects or a project's technical or financial alternatives.     

Applying Target Costing in the Development of Marketable and Environmentally Friendly Products from Swine Waste

Management of swine waste generated in the United States is a challenging problem facing engineers, farmers, scientists, regulators, and policy-makers. Technologies for processing and storing swine waste have not been fully developed and refined in a manner acceptable to the public and environmental regulators. The primary concerns with improperly disposed swine waste are the effects on human and livestock health, surface and groundwater quality, air quality, and conservation of nitrogen fertilizers (Hagenstein 2003 Hagenstein, P. R. 2003. Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs, Washington, D. C.: National Research Council, National Academy Press.  [Google Scholar]).

The purpose of this study is to demonstrate the concept of target costing by applying it to a very specific example: the production of biomethanol from swine manure. This study summarizes the analyses that outline a design and calculate a preliminary cost estimate for a proposed system for producing biomethanol from swine manure (initial process). In this study the target costing process is demonstrated with calculation of a target cost. This article also demonstrates an application of value engineering as a systematic, interdisciplinary examination of factors affecting the cost of a product so as to find means to fulfill the product's specified purpose at the required standards of quality and reliability and at an acceptable cost.

The article is organized as follows. First, the purpose of applying target costing methodology to the development of marketable by-products from swine manure is outlined. Next, target cost is calculated for biomethanol made from swine manure based on current methanol prices and currently available subsidies for biomethanol made from swine manure. A system for producing biomethanol from swine manure is described. The current cost is calculated for producing biomethanol. Concepts of value engineering are employed to reduce a significant cost component of the initial process resulting in Process II. Finally, value engineering is employed the second time to further reduce the cost of Process II yielding Process III.     

“Engineering Economics Jeopardy!” Mobile App for University Students

This article presents the “Engineering Economics Jeopardy!” mobile app development process and college students’ satisfaction assessment of the developed app. The app includes a general tools E-book, calculator, reference tables, conceptual questions, and calculation problems in an engaging fashion. The E-book is a summary of the key concepts of engineering economics. The calculator provides functions to solve basic engineering economics problems with formulas. The tables allow the users to compute discrete compound interest factors. Through this Jeopardy! game, users can compete with two virtual opponents that have artificial intelligence to answer conceptual questions and calculation problems. Different sets of problems range from the simple questions on the time value of money to more complex concepts, such as sensitivity analysis, Monte Carlo simulation, and supply–demand equilibrium. This app is intended to give students more opportunity to learn and practice concepts of engineering economics whenever and wherever they want using their mobile devices. Accomplishments of this work include the following:

• “Engineering Economics Jeopardy!” mobile app has been developed and distributed.

• Five thousand people have downloaded the app so far.

• The effectiveness of the developed app has been researched with 116 college students who were enrolled in engineering economics courses across two semesters.

     

Promoting Energy Efficiency in an Emerging Market: Insights and Intervention Strategies

Promoting energy efficiency and conservation is an urgent imperative in responding to the need to reduce carbon dioxide emissions, particularly in emerging markets. This article provides insights into factors that may enhance or impede the purchase of energy-efficient household appliances in Vietnam. It also suggests intervention strategies to enhance the motivators and mitigate the barriers associated with energy-efficient appliance purchases. Data were collected from shoppers in popular electronics and appliance stores. The findings reveal that consumer purchasing behaviors are motivated by long-term savings, environmental protection, social influence, green self-identity and innovative technologies. Major barriers include lack of information, low level of credibility of energy rating labels, high prices, time consumption and limited product range.

This article is of interest to policy-makers, social-environmental organizations, manufacturers and retailers in the development of more effective strategies for promoting energy efficiency and conservation. It extends current knowledge about environmentally responsible behavior in emerging markets such as Vietnam.