Hybrid approach with an expert system and a genetic algorithm to production management in the supply net

A new approach to solving production management problems in the supply net is proposed. An expert system designed to help companies in medium-term and short-term production planning is discussed. The proposed expert system considers alternative process plans for a job and outsourcing, when a bottleneck exists in the machine. The proposed hybrid system uses the output of the expert system as the input of the genetic algorithm. The output of the genetic algorithm is a near optimal schedule. The proposed method does not require any unrealistic assumptions. It can be used to solve highly complicated and non-linear functions of a realistic problem. Copyright © 2007 John Wiley & Sons, Ltd.     

Inter-local relations and trans-scaling through finance in Poland

Inter-local cooperation is difficult to measure. In Poland, however, the data-set concerning financial transfers between local government budgets (one of the most popular quantitative measures of cooperation) has never been described in scientific literature. This paper aims at contributing to fill this gap. On the basis of the budget expenditures of all Polish local governments, we applied two research methods: OLS regression and Heckman two-stage regression. The results show that the decision whether to get into cooperation, and the decision on the extent of involvement are driven by different factors.     

Social strategies that work

Although most companies have collected lots of friends and followers on social platforms such as Facebook, few have succeeded in generating profits there. That's because they merely port their digital strategies into social environments by broadcasting their commercial messages or seeking customer feedback. To succeed on social platforms, says Harvard Business School's Piskorski, businesses need to devise social strategies that are consistent with users' expectations and behavior in these venues--namely, people want to connect with other people, not with companies. The author defines successful social strategies as those that reduce costs or increase customers' willingness to pay by helping people establish or strengthen relationships through doing free work on a company's behalf. Citing successes at Zynga, eBay, American Express, and Yelp, Piskorski shows that social strategies can generate profits by helping people connect in exchange for tasks that benefit the company such as customer acquisition, marketing, and content creation. He lays out a systematic way to build a social strategy and shows how a major credit card company he advised used the method to roll out its own strategy.     

Network effects and preference heterogeneity in the case of mobile telecommunications markets

This paper demonstrates how revealed- and stated-preference analyses can be used for modeling network effects in the field of mobile telecommunications. The aim of this study was to verify if network effects may still play a role in the Polish mobile telecommunications market, measure their strength, identify their sources and variability across consumers by accounting for consumers' observable and unobservable preference heterogeneity, evaluate their monetary value to consumers, and finally, to verify if the marginal utility associated with network effects is constant. The analysis of consumers' revealed choices (currently used mobile telephone operator) allowed the identification of major differences between customer bases of incumbent and new entrant operators, and insight into the business strategies adopted in the presence of asymmetric regulation of mobile termination rates. The second part of the study—the analysis of the consumers' stated choices (made in carefully prepared and designed hypothetical choice situations, known as the choice experiments) made it possible to directly model consumers' utility functions and, in this way, investigate the nature of network effects in mobile telecommunications markets. From the results, the presence of strong network effects, which are related to the ratio of consumers' social network group using the same operator, and to the magnitude of on-net price discounts, is confirmed. These network effects can be disaggregated to pecuniary and non-pecuniary effects. Through the utilization of the random parameters multinomial logit model, consumers' observable and unobservable preference heterogeneity can be accounted for, which proved a scientifically revealing and potentially policy-relevant approach. The results might be of a particular interest to other researchers aiming at modeling consumers' preferences as well as to mobile telephone operators and regulatory authorities—it is shown that capacity for vigorous price competition between mobile operators is limited by non-price factors, which affect subscriber's choices, especially in the presence of asymmetric mobile termination rates.     

Is the Income Elasticity of the Willingness to Pay for Pollution Control Constant?

How willingness to pay for environmental quality changes as incomes rise is a central question in several areas of environmental economics. This paper explores both theoretically and empirically whether or not the willingness to pay (WTP) for pollution control varies with income. Our model indicates that the income elasticity of the marginal WTP for pollution reduction is only constant under very restrictive conditions. Our empirical analysis tests the null hypothesis that the elasticity of the WTP for pollution control with respect to income is constant, employing a multi-country contingent valuation study of eutrophication reduction in the Baltic Sea. Our findings reject this hypothesis, and estimate an income elasticity of the WTP for eutrophication control of 0.1–0.2 for low-income respondents and 0.6–0.7 for high-income respondents. Thus, our empirical results suggest that the elasticity is not constant but is always less than one. This has implications for how benefits transfer exercises, and for theoretical explanations of the environmental Kuznets curve.     

Marketing Dynamics and Management Excellence: The Sources of Successful Internationalization of a Food Processing Company from a Transition Economy (Case: MASPEX—Poland)

The article presents a case story of the fall and rise of the food industry in Poland's transition economy, illustrated with the example of one of its most successful companies. The author distinguishes 3 stages of the economic transition of Poland: Stage 1, in which the Polish food processing industry collapsed, faced with fierce foreign competition after the implementation of a strategy of liberalization and privatization; Stage 2 (since the late 1990s), when young, dynamic, and relatively well-educated Polish entrepreneurs and managers not only started to regain the local market but also began international expansion, intensifying exports, primarily to EU markets; Stage 3, during which the internationalization took the form of foreign direct investment outward into the former neighboring socialist/communist countries.

The MASPEX Group provides an excellent example of successful revival and expansion achieved thanks to the company's dynamic marketing strategy, executed by a young, dynamic, and highly professional management team.     

Bayesian Evaluation of DSGE Models with Financial Frictions

We evaluate two most popular approaches to implementing financial frictions into DSGE models: the Bernanke, Gertler, and Gilchrist ( 1999 ) setup, where frictions affect the price of loans, and the Kiyotaki and Moore ( 1997 ) model, where they concern the quantity of loans. We take both models to the data and check how well they fit it on several margins. Overall, comparing the models favors the Bernanke, Gertler, and Gilchrist framework. However, even this model does not make a clear improvement over the New Keynesian benchmark in terms of marginal likelihood and similarity of impulse responses to those obtained from a VAR.     

Risk Diversification on the Polish Capital Market

The basics of portfolio management theory and methods of efficient selection of assets and their financing have been created by Markowitz and Sharpe. They propose that risk diversification consists, generally speaking, of the increase in the number of securities in a portfolio. So, authors try to answer the question of how many securities have to be bought on a given market to assure a well-diversified portfolio, where the increase in the number of securities does not lead to a significant decrease in portfolio risk. To evaluate such a purpose on the Polish capital market, 20 companies were surveyed that are included in the WIG20 index in the period January 2–October 10, 2001. The returns were estimated on a weekly basis. The research shows that a portfolio of securities constructed, according to the Sharpe Model, has a wide application to the Polish capital market.*University of Szczecin—Poland. This paper was presented at the Fifty-Eighth InternationalAtlantic Economic Conference, October 6Y9, 2005, Chicago, U.S.A.