ILS-ESP An efficient, simple, and parameter-free algorithm for solving the permutation flow-shop problem

From a managerial point of view, the more effcient, simple, and parameter-free (ESP) an algorithm is, the more likely it will be used in practice for solving real-life problems. Following this principle, an ESP algorithm for solving the Permutation Flowshop Sequencing Problem (PFSP) is proposed in this article. Using an Iterated Local Search (ILS) framework, the so-called ILS-ESP algorithm is able to compete in performance with other well-known ILS-based approaches, which are considered among the most effcient algorithms for the PFSP. However, while other similar approaches still employ several parameters that can affect their performance if not properly chosen, our algorithm does not require any particular fine-tuning process since it uses basic "common sense" rules for the local search, perturbation, and acceptance criterion stages of the ILS metaheuristic. Our approach defines a new operator for the ILS perturbation process, a new acceptance criterion based on extremely simple and transparent rules, and a biased randomization process of the initial solution to randomly generate different alternative initial solutions of similar quality -which is attained by applying a biased randomization to a classical PFSP heuristic. This diversification of the initial solution aims at avoiding poorly designed starting points and, thus, allows the methodology to take advantage of current trends in parallel and distributed computing. A set of extensive tests, based on literature benchmarks, has been carried out in order to validate our algorithm and compare it against other approaches. These tests show that our parameter-free algorithm is able to compete with state-of-the-art metaheuristics for the PFSP. Also, the experiments show that, when using parallel computing, it is possible to improve the top ILS-based metaheuristic by just incorporating to it our biased randomization process with a high-quality pseudo-random number generator.

Condom use with steady partners among heterosexual people living with HIV in Europe: testing the information-motivation-behavioral skills model.

Guided by a modified information-motivation-behavioral skills model, this study identified predictors of condom use among heterosexual people living with HIV with their steady partners. Consecutive patients at 14 European HIV outpatient clinics received an anonymous, standardized, self-administered questionnaire between March and December 2007. Data were analyzed using descriptive statistics and two-step backward elimination regression analyses stratified by gender. The survey included 651 participants (n = 364, 56% women; n = 287, 44%). Mean age was 39 years for women and 43 years for men. Most had acquired HIV sexually and more than half were in a serodiscordant relationship. Sixty-three percent (n = 229) of women and 59% of men (n = 169) reported at least one sexual encounter with a steady partner 6 months prior to the survey. Fifty-one percent (n = 116) of women and 59% of men (n = 99) used condoms consistently with that partner. In both genders, condom use was positively associated with subjective norm conducive to condom use, and self-efficacy to use condoms. Having a partner whose HIV status was positive or unknown reduced condom use. In men, higher education and knowledge about condom use additionally increased condom use, while the use of erectile-enhancing medication decreased it. For women, HIV disclosure to partners additionally reduced the likelihood of condom use. Positive attitudes to condom use and subjective norm increased self-efficacy in both genders, however, a number of gender-related differences appeared to influence self-efficacy. Service providers should pay attention to the identified predictors of condom use and adopt comprehensive and gender-related approaches for preventive interventions with people living with HIV.

A Simple Access Pricing Rule to Achieve the Ramsey Outcome in Two-Way Access

In this paper, I consider a general and informationally effcient approach to determine the optimal access rule and show that there exists a simple rule that achieves the Ramsey outcome as the unique equilibrium when networks compete in linear prices without network-based price discrimination. My approach is informationally effcient in the sense that the regulator is required to know only the marginal cost structure, i.e. the marginal cost of making and terminating a call. The approach is general in that access prices can depend not only on the marginal costs but also on the retail prices, which can be observed by consumers and therefore by the regulator as well. In particular, I consider the set of linear access pricing rules which includes any fixed access price, the Efficient Component Pricing Rule (ECPR) and the Modified ECPR as special cases. I show that in this set, there is a unique access rule that achieves the Ramsey outcome as the unique equilibrium as long as there exists at least a mild degree of substitutability among networks' services.

Use of health services by residents at a seniors-only living facility

The objective of the study was to compare the use of medical and dental services by seniors residing at a seniors-only living facility and in the general community. It was a quantitative study, among 50 residents of the living facility and 173 in the general community. The data were collected between November 2011 and February 2012 through a questionnaire, and subjected to statistical analysis. Performance of clinical exams and satisfaction with health services was greater among seniors living in the general community; however, physical therapy treatment was more common among those living in the facility. The use of medical and dental services showed a statistically significant difference. The seniors in both groups need oral health monitoring and those living in the facility also require coverage by the Family Health Strategy. The presence of professionals with the right profile to adequately serve residents and the network of available services are determining factors for the success of this new housing policy.

The Simple Economics of Conglomeration with Bankruptcy Costs: Separate or Joint Financing?

Which projects should be financed through separate non-recourse loans (or limited- liability companies) and which should be bundled into a single loan? In the pres- ence of bankruptcy costs, this conglomeration decision trades off the benefit of co- insurance with the cost of risk contamination. This paper characterize this tradeoff for projects with binary returns, depending on the mean, variability, and skewness of returns, the bankruptcy recovery rate, the correlation across projects, the number of projects, and their heterogeneous characteristics. In some cases, separate financing dominates joint financing, even though it increases the interest rate or the probability of bankruptcy.

The Three Horsemen of Growth: Plague, War and Urbanization in Early Modern Europe

How did Europe overtake China? We construct a simple Malthusian model with two sectors, and use it to explain how European per capita incomes and urbanization rates could surge ahead of Chinese ones. That living standards could exceed subsistence levels at all in a Malthusian setting should be surprising. Rising fertility and falling mortality ought to have reversed any gains. We show that productivity growth in Europe can only explain a small fraction of rising living standards. Population dynamics - changes of the birth and death schedules - were far more important drivers of the longrun Malthusian equilibrium. The Black Death raised wages substantially, creating important knock-on effects. Because of Engel's Law, demand for urban products increased, raising urban wages and attracting migrants from rural areas. European cities were unhealthy, especially compared to Far Eastern ones. Urbanization pushed up aggregate death rates. This effect was reinforced by more frequent wars (fed by city wealth) and disease spread by trade. Thus, higher wages themselves reduced population pressure. Without technological change, our model can account for the sharp rise in European urbanization as well as permanently higher per capita incomes. We complement our calibration exercise with a detailed analysis of intra-European growth in the early modern period. Using a panel of European states in the period 1300-1700, we show that war frequency can explain a good share of the divergent fortunes within Europe.

Independent Living Program, Fall 2006

A Day in the Life of Agnes.

Independent Living Program, Summer 2006

Iowa's Visually-Impaired and Blind Seniors Gain Confidence and Independence!

Independent Living Program, Spring 2006

The Iowa Department for the Blind partnered with The Lodge of Ashworth retirement community in West Des Moines to bring information to visually impaired residents, friends and family. The Lodge furnished refreshments, and the Department furnished the programming.

Independent Living Program, Winter 2006

LENORE'S STORY Lenore Barnes began losing vision in her early eighties due to macular degeneration. In her mid-eighties she quit driving and purchased a CCTV. Her vision continued to decrease, and while the CCTV remained helpful it was of diminishing benefit.

Independent Living Program, Vol. 2, 2007

The Iowa Department for the Blind is the state agency that serves Iowans with vision loss. Services are free, confidential and available statewide. "There are no limitations to what you can do with training and a positive attitude." (All quotes in this newsletter are from former training participants). At the Iowa Department for the Blind, we believe in a positive approach to blindness. Vision loss alone should not prevent anyone from being independent. For this reason, we offer a wide variety of opportunities to obtain the skills necessary for independence.

Independent Living Program, Spring 2005

Rehabilitation Teachers -- Who are they and what do they do? Blindness Techniques to assist, in everyday activities and upcoming events all in this issue.