A continuous model for dynamic pricing under costly price modifications

This paper presents a heuristic method to solve a dynamic pricing problem under costly price modifications. This is a remarkably difficult problem that is solvable only under very few special cases. The method is applied to a more general form of the problem and is numerically tested for a variety of demand functions in the literature. The results show that the method is quite accurate, approximating the optimal profit within usually much less than 1\%. A more important result is that the accuracy tend to be much greater as the number of price changes increases, precisely when the underlying optimization problem becomes much harder, which makes this approach particularly desirable

Moral Biases in Intergroup Context

Even though people perceive their moral judgements as objective and unbiased, research suggests that they in fact make biased moral decisions that are then rationalized as objective. This project aimed to build on this prior work to further investigate the effect of intergroup biases on judgments of others’ morality. In the first line of this project, I aimed to investigate whether or not moral judgments are influenced by group membership where there is no prior information, beliefs, or emotions associated with the target group (i.e., in a minimal group setting). Participants read two versions of trolley dilemmas and judge either ingroup or outgroup targets. Across four experimental studies with minimal groups, I found evidence for group biases, even though the nature of patterns obtained varied. Overall, the findings suggest that group membership has a substantial influence on moral judgments even in minimal group settings, but given the inconsistency between the patterns obtained these warrant further investigation. Then, I aimed to investigate moral biases in pre-existing groups (specifically, men and women) and the role of relevant ideologies (sexism). I specifically focused on the role of a type of sexism that directly refers to women’s morality, i.e., benevolent sexism. To further specify the role of sexism in moral judgements, I also varied the moral extremity of the action. The results indicated that benevolent sexism led to more lenient judgements of women who displayed clearly immoral actions, especially among male participants (Study 5). However, the interplay between benevolent sexism and moral extremity was not moderated by target gender, indicating that this effect is not limited to judgements of women’s actions (Study 6). In the final study, I aimed to investigate the role of hostile sexism in counter-stereotypical female actions. The results revealed that hostile sexism negatively affected moral judgements of women who behaved counter-stereotypically, but not of men who displayed the same (stereotypically male) behaviour, but this was only the case for female participants

Linear integrated location-inventory models for service parts logistics network design

We present two integrated network design and inventory control problems in service-parts logistics systems. Such models are complicated due to demand uncertainty and highly nonlinear time-based service level constraints. Exploiting unique properties of the nonlinear constraints, we provide an equivalent linear formulation under part-warehouse service requirements, and an approximate linear formulation under part service requirements. Computational results indicate the superiority of our approach over existing approaches in the literature

An integrated model for cash transfer system design problem

This paper presents an integrated model that incorporates strategic, tactical, and operational decisions for a cash transfer management system of a bank. The aim of the model is to decide on the location of cash management centers, number and routes of vehicles, and the cash inventory management policies to minimize the cost of owning and operating a cash transfer system while maintaining a pre-defined service level. Owing to the difficulty of finding optimal decisions in such integrated models, an iterative solution approach is proposed in which strategic, tactical, and operational problems are solved separately via a feedback mechanism. Numerical results show that such an approach is quite effective in reaching greatly improved solutions with just a few iterations, making it a promising approach for similar integrated models

A two-level facility location and sizing problem for maximal coverage

This paper presents a two-stage hierarchical location problem for systems where the lower level facilities act as the first points contact for the customers while the upper level facilities act as suppliers of the lower level facilities that either serve them or provide advanced services to customers. Furthermore, more recent and realistic coverage constructs such as gradual and cooperative covering are included in our setting. Although our problem can be applicable in various settings, the most fitting application is in wireless telecommunication networks to determine the location of base stations and mobile switching centers. We have developed two competing formulations for the problem, each of which involve nonlinear components that are difficult to deal with. We then develop their respective linearizations and tested their performances. These formulations are solved by commercial optimizers for a set of reasonably large problem instances and it is found that majority of the problems can be solved within a maximum of 10% optimality gap within a short time

Yöresel Organik Ürünlerde Üretim ve Pazarlama Problemleri

Tarımsal ürün üretim sistemlerinde kimyasal girdi kullanılmadan, tamamen doğal girdilerle yapılan ürün yetiştiriciliği organik tarım olarak adlandırılmaktadır. Artan nüfusa paralel olarak ortaya çıkabilecek gıda açığına karşı tarımsal üretimi artırmaya yönelik çeşitli uygulamalar yapılmış ve önemli gelişmeler kaydedilmiştir. Sağlıklı beslenme ve çevre sağlığı açısından oldukça önemli bir uygulama olan organik tarım üretim modeli ülkemizin birçok kırsal kesiminde yerine getirilmesine rağmen tarımsal üretimle uğraşan kişiler bu önemli ürünlerden yeterince kazanç elde edememektedirler. Bu durumun en önemli sebepleri üreticilerin ürettikleri ürün konusunda yeterince bilgi sahibi olmamaları ile ilişkili olarak üretim, işleme ve paketleme yöntemlerinin ürün kalitesi ve sağlığına uygun bir şekilde düzenlenememesi ile pazarlama imkânlarından yeterince faydalanamama gibi durumlardır. Organik tarımsal üretim açısından önemli bir potansiyele sahip olan yöresel ürünlerin uygun yöntemlerle üretilip işlenerek daha sağlıklı şartlarda tüketicilere sunulmalarının sağlanması durumunda kırsal kesimdeki tarımsal ürün yetiştiricilerinin elde edecekleri gelirde artış sağlanabileceği gibi insan ve çevre sağlığına da önemli katkılar sağlanacaktır

Effects of different irrigation regimes on vegetative growth, fruit yield and quality of drip-irrigated apricot trees

This study was conducted during five growing seasons from 2004 to 2008 to investigate effects of different irrigation regimes on vegetative growth, fruit yield and quality of Salak apricot trees in semiarid climatic conditions. There were six irrigation treatments, five of which (S1, S2, S3, S4 and S5) were based on adjustment coefficients of class A pan evaporation (0.50, 0.75, 1.00, 1.25 and 1.50). The other treatment (S6) was regulated deficit irrigation treatment that was irrigated by applying 100% of class A pan evaporation until harvest, but was not irrigated after harvest. During the experimental years, the lowest values of irrigation water and evapotranspiration were obtained by S6 and S1 treatments, respectively, while the highest values were obtained for the S5 treatment. There were statistically significant vegetative growth differences among the treatments. The highest vegetative growth values were observed for the S5 and S4 treatments, while the lowest value was observed for the S6. Yields per tree and per unit crown volume did not show statistically significant differences among treatments in all the years studied, while the yield per unit trunk cross-sectional area showed statistically significant differences among treatments only in 2008. The S1 treatment showed higher yields per unit trunk crosssectional area and per unit crown volume than other treatments, while S5 treatment showed higher yield per tree than other treatments in all the years studied. There were no statistically significant fruit quality differences among the treatments. Consequently, the S1 treatment is recommended for apricot trees under the experimental conditions.Keyword: Apricot, class A pan, evapotranspiration, water deficit, vegetative growth, fruit yield and qualityAfrican Journal of Biotechnology Vol. 9(36), pp. 5902-5907, 6 September, 201

The efficiency of individual optimization in the conditions of competitive growth

The paper aims to discuss statistical properties of the multi-agent based model of competitive growth. Each of the agents is described by growth (or decay) rule of its virtual "mass" with the rate affected by the interaction with other agents. The interaction depends on the strategy vector and mutual distance between agents and both are subjected to the agent's individual optimization process. Steady-state simulations yield phase diagrams with the high and low competition phases (HCP and LCP, respectively) separated by critical point. Particular focus has been made on the indicators of the power-law behavior of the mass distributions with respect to the critical regime. In this regime the study has revealed remarkable anomaly in the optimization efficiency