Mathematical models have been used in many areas of supply chain management. In this paper, we present a mixed-integer non-linear programing (MINLP) model to solve a multi-period, closed-loop supply chains (CLSCs) with two echelons consist of producers and customers. In order to satisfy the demands, the producers are be able to order for materials in the beginning of each period for one or more...

This paper investigates the strategic use of cross-promotion for content producers in social media. In particular, we study how a producer chooses other producers to cross-promote so as to maximize the expected benefits of them cross-promoting him/her in return. Theories on homophily effect and social influence suggest that cross-promoted producers are more likely to cross-promote the initiator...

Enterobacterial isolates expressing the carbapenemase NDM-1 are emerging worldwide. Twenty-seven NDM-1-positive isolates of worldwide origin were included in this study to identify these strains as not only pathogens but also colonizers of normal flora for infection control screening. Although susceptibility to carbapenems varied, a combined test (IMP/IMP + EDTA), the Etest MBL, and automated s...

Software products do not provide consumption benefit unless a hardware product is installed in advance. In the market with this software – hardware relationship, a software producer sometimes finds that it is profitable to make its product compatible with only a certain hardware product. This incompatibility decision is considered as a vertical foreclosure. The conditions under which vertical m...

It is always somewhat difficult for presidents of societies like The Statistical and Social Inquiry Society to decide on an appropriate topic for a presidential address. It is not normally an occasion for an in-depth assessment of any particular issue but frequently takes the form of a "state of the art" expose relating to some areas of current interest. Some suggestions as to future directions...

Today we known that solar energy can be stored as edible biomass by photosynthesis, but 10,000 years ago this assumption was unthinkable. However, the Neolithic man could developed agriculture, based on plant germination observations. Nowadays, the systems used for food production are practically the same (Koning et al., 2008). But for neolitican man, the empirical observation of germination pr...

All over the world Distributed Generation is seen as a valuable help to get cleaner and more efficient electricity. Under this context distributed generators, owned by different decentralized players can provide a significant amount of the electricity generation. To get negotiation power and advantages of scale economy, these players can be aggregated giving place to a new concept: the Virtual ...

Hydraulic fracturing and other recent technological advances have dramatically increased the availability of natural gas in the United States. Moreover, since peaking in 2008, U.S. natural gas prices have fallen dramatically, and industry analysts are forecasting that prices will remain low for the next several decades (e.g., U.S. DOE 2013a). These trends have broad implications for energy mark...

We study the dynamics of co-evolution of producers and customers described by bit-strings representing individual traits. Individual ”sizelike” properties are controlled by binary encounters which outcome depends upon a recognition process. Depending upon the parameter set-up, mutual selection of producers and customers results in different types of attractors, either an exclusive niches regime...

This research evaluates the efficiency of swine firms differing by specialization type and employed technologies. Measures of technical, allocative, scale, economic, and overall efficiency are separately and jointly estimated for farrow-to-finish, farrow-to-feeder, feeder-tofinish, farrow-to-weanling, weanling-to-feeder, and mixed operations. Findings confirm appreciable differences in efficien...