Cooperation and profit allocation in distribution chains

We study the coordination of actions and the allocation of profit in distribution chains under decentralized control. We consider distribution chains in which a single supplier supplies goods for replenishment of stocks of several retailers who, in turn, sell these goods to their own separate markets. The goal of the supplier and the retailers is to maximize their individual profits. Since the optimal joint profit under centralized control is larger than the sum of the individual optimal profits under decentralized control, cooperation among firms by means of coordination of actions may improve individual profits. The effects of cooperation are studied by means of cooperative games. For each distribution chain we define a corresponding cooperative game and study its properties. Among others we show that such games are balanced. Based on the nice core structure a stable solution concept for these games is proposed and its properties are interpreted in terms of the underlying distribution chain. \u

The Rapid Rise of Supermarkets in Developing Countries: Induced Organizational, Institutional, and Technological Change in Agrifood Systems

There has been extremely rapid transformation of the food retail sector in developing regions in the past 5 to 10 years, accompanied by a further consolidation and multi-nationalization of the supermarket sector itself. This organizational change, accompanied by intense competition, has driven changes in the organization of procurement systems of supermarket chains, toward centralized and regionalized systems, use of specialized/dedicated wholesalers and preferred supplier systems, and demanding, private quality standards. These changes in the system have in turn determined the very recent rise of the use of contracts between supermarkets and agrifood producers in these regions to cover provision of services and provision for risk management, as well as requirements for demanding quality and safety attributes, which require substantial investment in technological change and upgrading at the producer level. This paper presents a brief discussion of these trends, followed by a conceptual framework to explain this phenomenon, illustrated with empirical evidence drawn mainly from Latin America.supermarket chains, procurement systems, quality standards, agrifood producers, Agribusiness,

How to vocally train transgender singers: A thorough literature review

The knowledge of training transgender voices is just beginning to make its way into mainstream music education. However, there needs to be more known and a curriculum in place to address this critical topic. Transgender students face many unique challenges in the voice studio, and educators must have the knowledge to teach these students. There are several elements to consider when training transgender students. These elements include the anatomical changes of masculinizing hormones on the body and voice, the anatomical changes of feminizing hormones on the body and voice, vocal exercises for both transfeminine and transmasculine students, how to choose repertoire for transgender students, how to create a safe and inclusive studio for all students, and the psychological component behind transgender voice training. In this paper, I will provide a summary of the research and scholarly discourse pertaining to these topics. The synthesis of research on these elements will be helpful for voice teachers and general music educators to help understand how to support and educate transgender students in their classrooms and voice studios

A Radiation hard bandgap reference circuit in a standard 0.13um CMOS Technology

With ongoing CMOS evolution, the gate-oxide thickness steadily decreases, resulting in an increased radiation tolerance of MOS transistors. Combined with special layout techniques, this yields circuits with a high inherent robustness against X-rays and other ionizing radiation. In bandgap voltage references, the dominant radiation-susceptibility is then no longer associated with the MOS transistors, but is dominated by the diodes. This paper gives an analysis of radiation effects in both MOSdevices and diodes and presents a solution to realize a radiation-hard voltage reference circuit in a standard CMOS technology. A demonstrator circuit was implemented in a standard 0.13 m CMOS technology. Measurements show correct operation with supply voltages in the range from 1.4 V down to 0.85 V, a reference voltage of 405 mV 7.5 mV ( = 6mVchip-to-chip statistical spread), and a reference voltage shift of only 1.5 mV (around 0.8%) under irradiation up to 44 Mrad (Si)

Confluence reduction for Markov automata

Markov automata are a novel formalism for specifying systems exhibiting nondeterminism, probabilistic choices and Markovian rates. Recently, the process algebra MAPA was introduced to efficiently model such systems. As always, the state space explosion threatens the analysability of the models generated by such specifications. We therefore introduce confluence reduction for Markov automata, a powerful reduction technique to keep these models small. We define the notion of confluence directly on Markov automata, and discuss how to syntactically detect confluence on the MAPA language as well. That way, Markov automata generated by MAPA specifications can be reduced on-the-fly while preserving divergence-sensitive branching bisimulation. Three case studies demonstrate the significance of our approach, with reductions in analysis time up to an order of magnitude

Inventory Games

AMS classifications: 90D12, 90B05.inventory management;information;cooperative games;proportional division

Exact numerical simulation of power-law noises

Many simulations of stochastic processes require colored noises: I describe here an exact numerical method to simulate power-law noises: the method can be extended to more general colored noises, and is exact for all time steps, even when they are unevenly spaced (as may often happen for astronomical data, see e.g. N. R. Lomb, Astrophys. Space Sci. {\bf 39}, 447 (1976)). The algorithm has a well-behaved computational complexity, it produces a nearly perfect Gaussian noise, and its computational efficiency depends on the required degree of noise Gaussianity.Comment: 14 postscript figures, accepted for publication on Phys. Rev.

Cessation of X-ray Pulsation of GX 1+4

We report results from our weekly monitoring campaign on the X-ray pulsar GX 1+4 with the {\em Rossi X-ray Timing Explorer} satellite. The spin-down trend of GX 1+4 was continuing, with the pulsar being at its longest period ever measured (about 138.7 s). At the late stage of the campaign, the source entered an extended faint state, when its X-ray (2-60 keV) flux decreased significantly to an average level of $\sim 3 \times 10^{-10} ergs cm^{-2} s^{-1}$. It was highly variable in the faint state; the flux dropped to as low as $\sim 3 \times 10^{-11} ergs cm^{-2} s^{-1}$. In several observations during this period, the X-ray pulsation became undetectable. We can, therefore, conclude conservatively that the pulsed fraction, which is normally $\gtrsim$ 70% (peak-to-peak), must have decreased drastically in those cases. This is very similar to what was observed of GX 1+4 in 1996 when it became similarly faint in X-ray. In fact, the flux at which the cessation of X-ray pulsation first occurred is nearly the same as it was in 1996. We suggest that we have, once again, observed the propeller effect in GX 1+4, a phenomenon that is predicted by theoretical models of accreting X-ray pulsars.Comment: 13 pages, 9 figures (available at http://www.physics.purdue.edu/~cui/ftp/cuifigs.tar.gz). To appear in Ap