A dynamic game with monopolist manufacturer and price-competing duopolist retailers

The paper considers a dynamic game with a single manufacturer who supplies two retailers. The manufacturer determines his production rate of a specific product, the rate of quality improvement efforts as well as the rate of advertising for the product. Each retailer controls her purchasing rate and the consumer sales price. Payments from a retailer to the manufacturer are determined by a wholesale price or a revenue-sharing scheme. The retailers operate in the same consumer market in which they compete in prices for the consumer demand. Nash equilibrium conditions are derived and numerical methods are employed to characterize equilibrium behavior of the players in a differential game of fixed and finite duration.     

弹性需求条件下供应链协作的批发价格机制研究

研究了一类由供应商与分销商组成的两级供应链在弹性需求下的协作机制设计问题.分析了供应商与分销商未进行任何协作时整个供应链的收益情况.在此基础上,对供应商与分销商进行协作时最优订货量与整个供应链的收益进行了分析.研究结果表明双方协作可以提高整个供应链系统的收益,但并不能保证合作各方的收益均会增加.为此,提出了一种基于不对称Nash协商模型的批发价格契约机制来协调合作双方的收益,并进行了数据模拟与综合分析.     

同存共荣的钢铁与气体

简介了氧、氮及氩气体在钢铁工业中的应用,阐述了钢铁工业在空分行业发展中的作用,展望了我国钢铁工业与空分行业的发展远景,就空分行业的持续发展提出了建议。     

Demand information sharing and channel choice in a dual-channel supply chain with multiple retailers

In this paper, under a dual-channel supply chain consisting of a manufacturer and multiple retailers, we investigate vertical and horizontal information sharing in different channel structures and the manufacturer’s choice on whether or not to keep a direct channel. To this end, we first study the dual-channel structure where uncertain demand is a linear function of price with a generalised-distribution base demand and show that the retailers have incentives to share information horizontally but not vertically, while the manufacturer is better off with vertical information sharing but its expected profit is not affected by horizontal information sharing. We next examine the retail-channel structure and find the basic results remain unchanged. Finally, we provide closed-form internal and external conditions under which the manufacturer can benefit from owning a dual-channel structure. Our study extends the existing literature by combining information sharing and dual-channel choice, introducing channel difference, discussing the impact of channel structure on horizontal and vertical sharing as well as providing interesting managerial insights for channel choice.     

Optimizing infrastructure network maintenance when benefits are interdependent

Network Topology Dependencies (NTD) are a class of externalities in the maintenance cost structure of infrastructure networks with applications to many network industries, including natural gas and water distribution pipelines. It is shown that the above externalities may be included to infrastructure maintenance decisions, if optimal maintenance is formulated as a Rhys-Balinski selection problem. A unique contribution is that this risk management problem is analyzed from the point of view of integrating quantitative analysis to organizational and inter-organizational decision processes. Hence, the importance of various procedural requirements is established in addition to computational efficiency and numerical accuracy. In particular, the benefits of sensitivity analysis facilitation and of avoiding manipulability are stressed. The proposed solution process achieves all four requirements. Special attention is paid to the role of submodularity and antitone differences in sensitivity analysis.This complete issue was revised and published online in November 2004. The previous version contained a false date. Correspondence to: Ioannis S. Papadakis     

Errors in measuring a group of interdependent parameters with a known distribution and correlation

Conclusions The technique described above for processing the results in measuring a group of correlated parameters is based on taking into consideration the correlation and distribution of parameters and serves to reduce the measurement error without changing the measuring instruments.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 9–12, August, 1967.     

The organization and control of an evolving interdependent population

Starting with Darwin, biologists have asked how populations evolve from a low fitness state that is evolutionarily stable to a high fitness state that is not. Specifically of interest is the emergence of cooperation and multicellularity where the fitness of individuals often appears in conflict with that of the population. Theories of social evolution and evolutionary game theory have produced a number of fruitful results employing two-state two-body frameworks. In this study, we depart from this tradition and instead consider a multi-player, multi-state evolutionary game, in which the fitness of an agent is determined by its relationship to an arbitrary number of other agents. We show that populations organize themselves in one of four distinct phases of interdependence depending on one parameter, selection strength. Some of these phases involve the formation of specialized large-scale structures. We then describe how the evolution of independence can be manipulated through various external perturbations.     

Assignment rules in robotic mobile fulfilment systems for online retailers

We study robotic mobile fulfilment systems for online retailers, where products are stored in movable shelves and robots transport shelves. While previous studies assume random assignment rule of workstations to robots, we propose an assignment rule based on handling speeds of workstations and design a neighbourhood search algorithm to find a near optimal assignment rule. We build semi-open queueing networks and use a two-phase approximate approach for performance estimation. We first replace workstation service processes by a composite service node and then solve the model by the matrix-geometric method. Simulations are used to validate the analytical models. Numerical experiments are conducted to compare random, handling-speeds-based, near optimal and optimal assignment rules, in terms of retrieval throughput time. The results show that the random assignment rule is not a good choice, the handling-speeds-based assignment rule significantly outperforms the random assignment rule when the workers have large handling time difference, and the neighbourhood search approach can provide an assignment rule that is very close to the optimal one, using a much shorter time. Moreover, we design the shelf blocks under the examined assignment rules, and find that the optimal width of shelf block decreases with the width to length ratio.     

“System-of-systems” approach for interdependent critical infrastructures

The study of the interdependencies within critical infrastructures (CI) is a growing field of research as the importance of potential failure propagation among infrastructures may lead to cascades affecting all supply networks. New powerful methods are required to model and describe such “systems-of-systems” (SoS) as a whole. An overall model is required to provide security and reliability assessment taking into account various kinds of threats and failures. A significant challenge associated with this model may be to create “what-if” scenarios for the analysis of interdependencies. In this paper the interdependencies between industrial control systems (ICS), in particular SCADA (Supervisory Control and Data Acquisition), and the underlying critical infrastructures to address the vulnerabilities related to the coupling of these systems are analyzed. The modeling alternatives for system-of-systems, integrated versus coupled models, are discussed. An integrated model contains detailed low level models of (sub)systems as well as a high level model, covering all hierarchical levels. On the other hand, a coupled model aggregates different simulated outputs of the low level models as inputs at a higher level. Strengths and weaknesses of both approaches are analyzed and a model architecture for SCADA and the “system under control” are proposed. Furthermore, the HLA simulation standard is introduced and discussed in this paper as a promising approach to represent interdependencies between infrastructures. To demonstrate the capabilities of the HLA standard for the interdependencies study, an exemplary application and some first results are also briefly presented in this paper.     

Option contracts for online celebrities as retailers in supply chains

The online celebrity economy, also called the internet celebrity economy, is growing rapidly in China. Celebrity retailers are usually demand sensitive and capital constrained. The capital constraints along with information asymmetry often render supply chains inefficient when manufacturers are producing at non-optimal levels. Few studies have shed light on the online celebrity supply chain, especially with respect to options. In this study, we examine how option contracts can coordinate supply chains. We find that a capital-constrained retailer can achieve more profitable orders when given an option. The manufacturer – without the full information of market demand – also benefits from offering an option to the retailer. Our numerical case shows that the options contract generates different payoffs depending on the capital of the retailer.     

A self-calibrating radon monitor with statistical discrimination

A radon monitor, able to perform the measurement of the radon and its progeny volumic activity, in a gamma-ray or natural radiation background field, was developed. The instrument consists of a 10 l ionization chamber, a high voltage source, an integrating preamplifier, a data acquisition system and a personal computer. A new method for self-calibration of Radon volumic activity measurements, based on the alpha counting with an ionization chamber is also presented.     

密度计在油料批发中的正确使用

本文介绍了密度计在汽油批发中的使用情况,分析了在油料批发中由于密度检测而引起的计量误差问题,并作了详细分析和计算,提出了在汽油批发中正确使用密度计的方法,避免计量纠纷和商业欺诈行为。     

An approach to design interface topologies across interdependent urban infrastructure systems

This paper proposes an approach to design or retrofit interface topologies to minimize cascading failures across urban infrastructure systems. Four types of interface design strategies are formulated based on maximum network component degree, maximum component betweenness, minimum Euclidean distance across components and component reliability rankings. To compute and compare strategy effectiveness under multiple hazard types, this paper introduces a global annual cascading failure effect (GACFE) metric as well as a GACFE-based cost improvement (GACI) metric. The GACI metric quantifies the improvement of the strategy effectiveness per kilometer increment of interdependent link length (ILL) relative to a reference strategy with minimum ILL. Taking as examples the power and gas transmission systems in Harris County, Texas, USA, optimum interface designs under random and hurricane hazards are discussed. Findings include that the strategy based on reliability rankings minimizes the GACFE metric, and decreases the GACI value relative to a reference practical strategy by 10-15% under different power grid safety margins. Such metrics will contribute to coupled utility system design or retrofit given that current guidelines or recommended practices in the utility industry mostly rely on minimum Euclidean distances and are yet to include interdependent effects in their provisions.     

Measure of the bullwhip effect considering the market competition between two retailers

In order to consider the market competition, a new supply chain with one supplier and two retailers is established in this paper. Two retailers employ different AR(1) demand processes, respectively, and an order-up-to inventory policy characterises the inventory decisions. The bullwhip effect in this supply chain is measured under the moving average forecasting technique. We investigate the effects of the lead time, the span of forecast, market competition and the consistency of demand volatility on the bullwhip effect using the algebraic analysis and numerical simulation. Conclusions indicate that different factors lead to the bullwhip effect following different patterns in the supply chain. Moreover, some suggestions are present to help managers to control parameters that yield the lower bullwhip effect.     

Two-dimensional neutron scintillation detector with optimal gamma discrimination

For a two-dimensional scintillation neutron detector based on position-sensitive photomultipliers a digital differential discrimination unit has been developed which minimizes the gamma sensitivity of the detector and was necessary because of position- dependent PM gain. The digital upper and lower discrimination levels are set position-dependent due to the position-dependent photomultiplier gain which is obtained from calibration measurements. Narrow discriminator windows can be used to reduce the gamma background drastically without affecting the homogeneous neutron sensitivity of the detector. The new discrimination method is described and its function is tested with neutrons.     

Contrast discrimination with pulse trains in pink noise

Detection performance was measured with sinusoidal and pulse-train gratings. Although the 2.09-cycles-per-degree pulse-train, or line, grating contained at least eight harmonics all at equal contrast, it was no more detectable than its most detectable component. The addition of broadband pink noise designed to equalize the detectability of the components of the pulse train made the pulse train approximately a factor of 4 more detectable than any of its components. However, in contrast-discrimination experiments, with a pedestal or masking grating of the same form and phase as the signal and with 15% contrast, the noise did not affect the discrimination performance of the pulse train relative to that obtained with its sinusoidal components. We discuss the implications of these observations for models of early vision, in particular the implications for possible sources of internal noise.     

利他偏好下基于批发价格契约的供应链协调

将决策主体的利他偏好行为引入供应链决策模型,建立了批发价格折扣契约下由自利偏好\利他偏好的供应商、零售商组成的二级供应链,即完全自利型供应链、零售商利他型供应链、供应商利他型供应链、完全利他型供应链。通过数理模型推导和数值分析得出:供应商(零售商)更愿意与利他型零售商(供应商)进行合作;零售商的利他偏好行为不能缓减供应链"双重边际效应",供应商利他偏好能缓减却不能消除供应链"双重边际效应",但供应商和零售商的利他行为都有利于增加供应链效用。这些理论能够为供应链决策主体选择合作伙伴类型提供理论支持,并丰富行为供应链的研究内容。