Social and Behavioral Sciences Commons^™

Tight Representation Of Logical Constraints As Cardinality Rules, John Hooker, Hong Yan

John Hooker

We address the problem of finding a "tight" representation of complex logical constraints in a mixed integer programming model by describing a convex hull representation of cardinality rules.

Approximate Compilation Of Constraints Into Multivalued Decision Diagrams, Tarik Hadzic, John Hooker, Barry O'Sullivan, Peter Tiedemann

John Hooker

We present an incremental refinement algorithm for approximate compilation of constraint satisfaction models into multivalued decision diagrams (MDDs). The algorithm uses a vertex splitting operation that relies on detection of equivalent paths in the MDD. Although the algorithm is quite general, it can be adapted to exploit constraint structure by specializing the path equivalence test to particular constraints.We show how to modify the algorithm in a principled way to obtain an approximate MDD when the exact MDD is too large for practical purposes. This is done by replacing the equivalence test with a constraint-specific measure of distance. We demonstrate the …

Testing Heuristics: We Have It All Wrong, John Hooker

John Hooker

The competitive nature of most algorithmic experimentation is a source of problems that are all too familiar to the research community. It is hard to make fair comparisons between algorithms and to assemble realistic test problems. Competitive testing tells us which algorithm is faster but not why. Because it requires polished code, it consumes time and energy that could be better spent doing more experiments. This article argues that a more scientific approach of controlled experimentation, similar to that used in other empirical sciences, avoids or alleviates these problems. We have confused research and development; competitive testing is suited only …

Optimal Design Of Truss Structures By Logic-Based Branch And Cut, S. Bollapragada, Omar Ghattas, John Hooker

John Hooker

The truss design problem is to find the optimal placement and size of structural bars that can support a given load. The problem is nonlinear and, in the version addressed here, the bars must take certain discrete sizes. It is shown that a logic-based method that dispenses with integer variables and branches directly on logical disjunctions can solve substantially larger problems than mixed integer programming, even though the nonlinearities disappear in the mixed integer model. A primary purpose of the paper is to investigate whether advantages of logic-based branching that have been demonstrated elsewhere for linear problems extend to nonlinear …

Optimal Movement Of Factory Cranes, Ionuţ Aron, Latife Genç-Kaya, Iiro Harjunkoski, Samid Hoda, John Hooker

John Hooker

We study the problem of finding optimal space-time trajectories for two factory cranes or hoists that move along a single overhead track. Each crane is a assigned a sequence of pickups and deliveries at specified locations that must be performed within given time windows. The cranes must be operated so as not to interfere with each other, although one crane may need to yield to another. The objective is generally to follow a production schedule as closely as possible. We show that only certain types of trajectories need be considered to obtain an optimal solution. This simplifies the operation of …

Mixed Logical-Linear Programming, John Hooker, M. Osorio

John Hooker

Mixed logical/linear programming (MLLP) is an extension of mixed integer/linear programming (MILP). It can represent the discrete elements of a problem with logical propositions and provides a more natural modeling framework than MILP. It can also have computational advantages, partly because it eliminates integer variables when they serve no purpose, provides alternatives to the traditional continuous relaxation, and applies logic processing algorithms. This paper surveys previous work and attempts to organize ideas associated with MLLP, some old and some new, into a coherent framework. It articulates potential advantages of MLLP's wider choice of modeling and solution options and illustrates some …

Good And Bad Futures For Constraint Programming (And Operations Research), John Hooker

John Hooker

Two futures are sketched for constraint programming and operations research. In one, they continue their present emphasis on computational methods. In the other, they are empirical sciences dedicated to prescriptive modeling of human activities, with computation playing an ancillary role. The second future is defended as one in which the two fields, which are at root one field, maintain their vitality and make a more effective contribution to solving the problems of an increasingly complex world.

A Linear Programming Framework For Logics Of Uncertainty, K. Andersen, John Hooker

John Hooker

Several logics for reasoning under uncertainty distribute “probability mass” over sets in some sense. These include probabilistic logic, Dempster-Shafer theory, other logics based on belief functions, and second-order probabilistic logic. We show that these logics are instances of a certain type of linear programming model, typically with exponentially many variables. We also show how a single linear programming package can implement these logics computationally if one “plugs in” a different column generation subroutine for each logic, although the practicality of this approach has been demonstrated so far only for probabilistic logic.

Simpl: A System For Integrating Optimization Techniques, Ionuţ Aron, John Hooker, Tallys Yunes

John Hooker

In recent years, the Constraint Programming (CP) and Operations Research (OR) communities have explored the advantages of combining CP and OR techniques to formulate and solve combinatorial optimization problems. These advantages include a more versatile modeling framework and the ability to combine complementary strengths of the two solution technologies. This research has reached a stage at which further development would benefit from a general-purpose modeling and solution system. We introduce here a system for integrated modeling and solution called SIMPL. Our approach is to view CP and OR techniques as special cases of a single method rather than as separate …

A Framework For Integrating Solution Methods, John Hooker

John Hooker

We describe a modeling framework that integrates mathematical programming (MP), constraint programming (CP) and heuristic methods.

Corruption From A Cross-Cultural Perspective, John Hooker

John Hooker

This paper views corruption as activity that tends to undermine a cultural system. Because cultures operate in very different ways, different activities are corrupting in different parts of the world. The paper analyzes real-life situations in Japan, Taiwan, India, China, North America, sub-Saharan Africa, the Middle East, and Korea to distinguish actions that structurally undermine a cultural system from those that are merely inefficient or are actually supportive. Activities such as nepotism or cronyism that are corrupting in the rule-based cultures of the West may be functional in relationship-based cultures. Behavior that is normal in the West, such as bringing …

Solving The Incremental Satisfiability Problem, John Hooker

John Hooker

Given a set of clauses in propositional logic that have been found satisfiable, we wish to check whether satisfiability is preserved when the clause set is incremented with a new clause. We describe an efficient implementation of the Davis-Putnam-Loveland algorithm for checking the satisfiability of the original set. We then show how to modify the algorithm for efficient solution of the incremental problem, which is NP-complete. We also report computational results.

Resolution And The Integrality Of Satisfiability Problems, John Hooker

John Hooker

No abstract provided.

Logic-Based Benders Decomposition, John Hooker, G. Ottosson

John Hooker

Benders decomposition uses a strategy of “learning from one’s mistakes.” The aim of this paper is to extend this strategy to a much larger class of problems. The key is to generalize the linear programming dual used in the classical method to an “inference dual.” Solution of the inference dual takes the form of a logical deduction that yields Benders cuts. The dual is therefore very different from other generalized duals that have been proposed. The approach is illustrated by working out the details for propositional satisfiability and 0-1 programming problems. Computational tests are carried out for the latter, but …

Some Business-Related Ethical Issues In Engineering, John Hooker

John Hooker

Engineering has always been related to business, but now more than ever. Engineers are increasingly involved in startup companies in which they make business decisions as well as engineering decisions. Even in large firms, highly integrated product development cycles bring engineers into closer contact with marketing and other business people than in years past. Engineers must now think about ethical issues that were once the province of business managers. In addition, the rapid growth of biotechnology and e-commerce has created a new ethical landscape in which engineers must operate.

The aim here is to examine a few of the issues …

Mixed Global Constraints And Inference In Hybrid Clp-Ip Solvers, Greger Ottosson, Erlendur Thorsteinsson, John Hooker

John Hooker

The complementing strengths of Constraint (Logic) Programming (CLP) and Mixed Integer Programming (IP) have recently received significant attention. Although various optimization and constraint programming packages at a first glance seem to support mixed models, the modeling and solution techniques encapsulated are still rudimentary. Apart from exchanging bounds for variables and objective, little is known of what constitutes a good hybrid model and how a hybrid solver can utilize the complementary strengths of inference and relaxations. This paper adds to the field by identifying constraints as the essential link between CLP and IP and introduces an algorithm for bidirectional inference through …

E-Commerce Patterns In South Asia: A Look Beyond Economics, Nir Kshetri, Nikhilesh Dholakia

Nikhilesh Dholakia

Conflicting and complex forces are shaping the diffusion patterns of the Internet and e-commerce in South Asia. Drawing upon the literature on institutional theory, we explore the drivers and inhibitors of the Internet in South Asian countries. We examine the influence of the three pillars of institutions (Scott, 1995) on the digital world of South Asia. The paper discusses how regulatory, normative, and cognitive institution–such as laws, relationships, culture, and habit–have shaped the diffusion patterns of the Internet and e-commerce in South Asia.

A Classical-Marxian Model Of Education, Growth And Distribution, Amitava Dutt, Roberto Veneziani

Roberto Veneziani

This paper develops a classical-Marxian macroeconomic model to examine the growth and distributional consequences of education. First, the role of education in skill formation is considered and it is shown that an expansion in education will promote growth and have beneficial distributional effects within the working class, but it will redistribute income from workers to capitalists. Second, the model is extended analyze the broader political economic consequences of education on class relations and class conflict. The model suggests the importance of a progressive type of education rather than one which weakens the power workers, for it allows for equitable growth …

Undergraduate Economics Journals: Learning By Doing, Michael Seeborg, Robert Leekley, Stephanie Davis-Kahl

Michael Seeborg

Although there are currently only a few undergraduate journals in economics, we expect their numbers to increase substantially in the future because of several developments: 1) research and writing activity is increasing in economics programs, 2) online publication is now more feasible and cost efficient than ever, and 3) students are increasingly aware of their on-line identity and desire to project a positive and professional image. Since increasing use of undergraduate journals might benefit a number of students, including potential article authors, article reviewers, and editors, there is a need to begin to assess the educational benefits of participation in …

Regional Integration And Transnational Labor Strategies Under Nafta, Maria Cook

Maria Lorena Cook

[Excerpt] This paper argues that while the internationalization of the economy has tended to weaken national labor movements, the internationalization of domestic politics may expand the traditional arenas for strategic action for labor unions. In particular, the North American Free Trade Agreement has been portrayed by some of its many critics as representing the consolidation of a neoconservative or neoliberal project that will not only shape the future economic development of the region, but also constrain its social policies and limit its political options (Grinspun and Cameron 1993: Chapter 1). However, these same critics have also noted that the debate …

A Commitment Theory Of Subsidy Agreements, Daniel Brou, Michele Ruta

Daniel Brou

This paper examines the rationale for the rules on domestic subsidies in international trade agreements through a framework that emphasizes commitment. We build a model where the policy-maker has a tariff and a production subsidy at its disposal, taxation can be distortionary and the import-competing sector lobbies the government for favorable policies. The model shows that, under political pressures, the government will turn to subsidies when its ability to provide protection is curtailed by a trade agreement that binds tariffs only (policy substitution problem). When the factors of production are mobile in the long-run, but the investments are irreversible in …

When Birds Of A Feather Don’T Flock Together: Different Scientists And The Roles They Play In Biotech R&D Alliances, Annapoornima Subramaniam, Kwanghui Lim, Pek-Hooi Soh

Kwanghui Lim

A firm's ability to produce high-impact innovations depends upon the nature of its R&D alliances as well as its composition of scientific human capital. The firm's scientific human capital is made up of its scientists, who produce valuable research outputs and who engage with the broader scientific community, thus helping the firm to integrate new knowledge from universities and other firms. In this paper, we examine heterogeneity within the firm's scientific human capital, emphasizing the distinct role of ‘bridging scientists’ who engage in two related but dissimilar scientific activities: patenting and publishing. Using a panel dataset of 222 firms in …

Undergraduate Personnel Economics (Ilrle/Econ 4430), Matthew Freedman

Matthew Freedman

In this course, students will be expected to apply economic theories to human resource management issues. The course will provide students with a rigorous framework in which to understand and analyze real-world personnel policies, their implementation, and their effects. Topics and issues we will discuss include human capital theory, hiring standards and screening, productivity and performance measurement, compensation schemes, layoffs and buyouts, training, teamwork, performance incentives, benefits, worker empowerment, and employee evaluation programs. Students will demonstrate their mastery of the subject through class participation as well as in exams, problem sets, and a group project.

Course materials are posted on …

Alternative Estimators Of Cointegrating Parameters In Models With Non-Stationary Data: An Application To Us Export Demand, James Forest, Paul Turner

James J Forest

This paper presents Monte Carlo simulations which compare the empirical performance of two alternative single equation estimators of the equilibrium parameters in a dynamic relationship. The estimators considered are Stock and Watson’s dynamic ordinary least squares (DOLS) estimator and Bewley’s transformation of the general autoregressive distributed lag model. The results indicate that the Bewley transformation produces a lower mean-square error as well as superior serial correlation properties even with lower truncation lags for the lagged variables included in the estimation equation. An application is then provided which examines the nature of the equilibrium relationship between aggregate US exports, world trade …

Undergraduate Intermediate Microeconomics - Math-Intensive (Bepp 250), Matthew Freedman

Matthew Freedman

This course will introduce you to “managerial economics”, the application of microeconomic theory to management problems. Microeconomic theory is a remarkably useful body of ideas for understanding and analyzing the behavior of individuals and firms in a variety of contexts. The goal of the course is to get you to internalize this body of theory well enough so that you can rigorously and efficiently analyze management—as well as other—problems in an economic framework. While this is a “tools” course, we will cover many real-world applications, particularly business applications, throughout the course. We will depart from usual microeconomic policy courses with …

Determinants Of Stock Price Movements In Nigeria: Evidence From Monetary Variables, Anthony Orji

ANTHONY ORJI

Abstract Most studies conducted on the determinants of stock price movements in Nigeria have been done on theoretical basis with no quantitative empirical evidence to support their postulations. Consequently, this study examined the macroeconomic determinants of stock price movements in Nigeria using detailed econometric framework in order to provide the foundation for evidence-based policies. Both the long-run and short run dynamic relationships between the stock price movement and the macroeconomic variables were analyzed with time series data that spanned from 1985 to 2010 using the Engle-Granger two-step cointegration test. We established that there is no cointegration between the variables, indicating …

Pay-What-You-Want Pricing And Competition: Breaking The Bertand Trap, Yong Chao, Jose Fernandez, Babu Nahata

Yong Chao

Pay-What-You-Want (PWYW) pricing is a recent participative pricing strategy where a seller offers a good or service for any price consumers want to pay, including zero or some minimum payment. This paper provides a theoretical framework to study strategic effects of the PWYW pricing under duopoly by incorporating behavioral considerations of consumers in making voluntary payments when they could be freeloaders. Without identifying any particular behavioral factor, we assume that consumers feel a sense of guilt when they pay less than their reference points. It is shown that the PWYW pricing can be a profitable marketing strategy than the conventional …

Metaphor, Media, And The Market, Ann Williams

Ann E Williams

No abstract provided.

A Second Look At Enrollment Changes After The Kalamazoo Promise, Brad Hershbein

Brad J. Hershbein

While previous research has documented how the Kalamazoo Promise, the most prominent and generous place-based college scholarship program, increased enrollment in Kalamazoo Public Schools, this paper qualifies and quantifies the characteristics of students who were induced to enter—or stay—in the district. In particular, it analyzes the origins and destinations, socioeconomic composition, and school-level sorting behavior associated with student flows around the time of the Promise announcement. These dimensions are more subtle than changes in the volume of students or measures of their individual success, but they are equally important to understand for communities exploring the feasibility of place-based scholarships as …

Concentration And Competitive Conditions In The South Eastern European Banking Industry, London (Uk), Francesco Guidi

Francesco Guidi

No abstract provided.