An algorithm for finding input–output constrained convex sets in an acyclic digraph

A set X of vertices of an acyclic graph is convex if any vertex on a directed walk between elements of X is itself in X. We construct an algorithm for generating all input–output constrained convex (IOCC) sets in an acyclic digraph, which uses several novel ideas. We show that the time complexity of our algorithm significantly improves the best one known from the literature. IOCC sets of acyclic digraphs are of interest in the area of modern embedded processor technology.     

Low-carbon building assessment and multi-scale input–output analysis

Presented as a low-carbon building evaluation framework in this paper are detailed carbon emission account procedures for the life cycle of buildings in terms of nine stages as building construction, fitment, outdoor facility construction, transportation, operation, waste treatment, property management, demolition, and disposal for buildings, supported by integrated carbon intensity databases based on multi-scale input–output analysis, essential for low-carbon planning, procurement and supply chain design, and logistics management.     

Estimating non-convex production sets – imposing convex input sets and output sets in data envelopment analysis

In this paper, we present Data Envelopment Analysis models for estimating non-convex production sets. In contrast to the Banker et al. (Banker, R.D., Charnes, A. and Cooper, W.W., 1984. Management Science 30 (9), 1078–1092) model, these models give statistically consistent estimators for production sets that are non-convex, but do have convex input sets and/or convex output sets, as is typically assumed in micro-economic theory. In addition, these models suffer less from a finite sample error than the Free Disposable Hull (Deprins, D., Simar, L., Tulkens, H., 1984. In: Marchand, M., Pestieu, P., Tulkens, H. (Eds.), The Performance of Public Enterprises. North-Holland, Amsterdam, pp. 243–267) model.     

Resources use and greenhouse gas emissions in urban economy: Ecological input–output modeling for Beijing 2002

The embodiment of natural resources and greenhouse gas emissions for the urban economy of Beijing economy 2002 by a physical balance modeling is carried out based on an extension of the economic input–output table into an ecological one integrating the economy with its various environmental driving forces. Included resources and greenhouse gas emissions belong to six categories as energy resources in terms of primary energy and secondary energy; water resource; emissions of CO₂, CH₄, and N₂O; exergy in terms of energy sources, biological resources and minerals; and solar emergy and cosmic emergy in terms of climate resources, soil, energy sources, and minerals.     

A receding horizon D-optimization approach for model identification–oriented input design and application in combustion engines

In this paper, a receding horizon D-optimization approach for model identification–oriented input design is proposed, and a practical application is demonstrated for internal combustion engines. The proposed approach consists of a recursive parameter identification algorithm and an input signal design algorithm; where the latter provides D-optimal excitation signal for the adaptation of the parameter estimation in the following identification phase. The D-optimization algorithm is constructed with the Continuation/GMRES method, which provides an approximate solution according to the current parameter of the model. To validate effectiveness and feasibility of the proposed approach, testing results applying the proposed approach to an internal combustion engine are demonstrated and conducted on a full-scale engine test bench.     

Can hazardous waste supply chain ‘hotspots’ be identified using an input–output framework?

The paper examines a method to attribute hazardous waste streams to regional production and consumption activity, and to connect these same waste streams through to different management options. We argue that a method using an input–output framework provides useful intelligence for decision makers seeking to connect elements of the management of the hazardous waste hierarchy to production and to different patterns and types of final consumption (of which domestic household consumption is one). This paper extends application of conventional demand driven input–output attribution methods to identify hazardous waste ‘hotspots’ in the supply chains of different final consumption goods and consumption groups. Using a regional case study to exposit the framework and its use, we find that domestic government final consumption of public administration production indirectly drives hazardous waste generation that goes to landfill, particularly in the domestic construction and sanitary services sectors, but also in the manufacture of wood products.     

Carbon emissions and resources use by Chinese economy 2007: A 135-sector inventory and input–output embodiment

A 135-sector inventory and embodiment analysis for carbon emissions and resources use by Chinese economy 2007 is presented in this paper by an ecological input–output modeling based on the physical entry scheme. Included emissions and resources belong to six categories as: (1) greenhouse gas (GHG) in terms of CO₂, CH₄, and N₂O; (2) energy in terms of coal, crude oil, natural gas, hydropower, nuclear power, and firewood; (3) water in terms of freshwater; (4) exergy in terms of coal, crude oil, natural gas, grain, bean, tuber, cotton, peanut, rapeseed, sesame, jute, sugarcane, sugar beet, tobacco, silkworm feed, tea, fruits, vegetables, wood, bamboo, pulp, meat, egg, milk, wool, aquatic products, iron ore, copper ore, bauxite, lead ore, zinc ore, pyrite, phosphorite, gypsum, cement, nuclear fuel, and hydropower; (5) and (6) solar and cosmic emergies in terms of sunlight, wind power, deep earth heat, chemical power of rain, geopotential power of rain, chemical power of stream, geopotential power of stream, wave power, geothermal power, tide power, topsoil loss, coal, crude oil, natural gas, ferrous metal ore, non-ferrous metal ore, non-metal ore, cement, and nuclear fuel. Accounted based on the embodied intensities are carbon emissions and resources use embodied in the final use as rural consumption, urban consumption, government consumption, gross fixed capital formation, change in inventories, and export, as well as in the international trade balance. The resulted database is basic to environmental account of carbon emissions and resources use at various levels.     

Combined effects of correlated bounded noises and weak periodic signal input in the modified FitzHugh–Nagumo neural model

We study the dynamics of neurons via a bistable modified stochastic FitzHugh–Nagumo model having two stable fixed points separated by one unstable fixed point. Due to the ability of a neuron to detect and enhance weak information transmission, we show numerically that starting from the resting potential, we get firing activities (spiking) when operating slightly beyond the supercritical Hopf bifurcation. For real biological systems which are sometimes embedded in the complex environment, we observe that a gradual increase or decrease noise intensities did not result in a gradual change of the membrane potential distribution thanks to noise induced transition phenomena. We shown analytically that for zero correlation between two sine Wiener noises, additive noise has no effect on the transition between monostable and bistable phase on the neural model. We adapted a general expression of the signal-to-noise ratio for a general two-state theory extended in the asymmetric case and non-Gaussian noises in our model to study the influence of noise strength in stochastic resonance. Our investigation revealed that in the evolution of excitable system, neurons may use noises to their advantage by enhancing their sensitivity near a preferred phase to detect external stimuli or affect the efficiency and rate of information processing.     

A two‐level queueing network model with blocking and non‐blocking messages

We analyze a novel twolevel queueing network with blocking, consisting of N level1 parallel queues linked to M level2 parallel queues. The processing of a customer by a level1 server requires additional services that are exclusively offered by level2 servers. These level2 servers are accessed through blocking and nonblocking messages issued by level1 servers. If a blocking message is issued, the level1 server gets blocked until the message is fully processed at the level2 server. The queueing network is analyzed approximately using a decomposition method, which can be viewed as a generalization of the wellknown twonode decomposition algorithm used to analyze tandem queueing networks with blocking. Numerical tests show that the algorithm has a good accuracy.     

Analysis and numerical simulation of an induction–conduction model arising in steel heat treating

The goal of steel heat treating is to create a hard enough part over certain critical surfaces or volumes of the workpiece and at the same time keeping its ductility properties all over the rest of the workpiece.     

Pricing American currency options in an exponential Lévy model

In this article the problem of the American option valuation in a Lévy process setting is analysed. The perpetual case is first considered. Without possible discontinuities (i.e. with negative jumps in the call case), known results concerning the currency option value as well as the exercise boundary are obtained with a martingale approach. With possible discontinuities of the underlying process at the exercise boundary (i.e. with positive jumps in the call case), original results are derived by relying on first passage time and overshoot associated with a Lévy process. For finite life American currency calls, the formula derived by Bates or Zhang, in the context of a negative jump size, is tested. It is basically an extension of the one developed by Mac Millan and extended by Barone‐Adesi and Whaley. It is shown that Bates' model generates pretty good results only when the process is continuous at the exercise boundary.     

Introducing internal model to robust output synchronization of FitzHugh–Nagumo neurons in external electrical stimulation

A novel internal model control method is proposed for the robust output synchronization of FizHugh–Nagumo (FHN) neurons under external electrical stimulation. The output synchronization problem can be converted into a robust stabilization problem of an augmented system consisting of the original given plant and an internal model. Hence, the design procedures include the design of a satisfied internal model and a proper state-feedback stabilizer for this augmented system. The stability analysis of the resulting closed-loop system leads to semiglobal Lyapunov asymptotic stability of the robust output synchronization achieved for some appointed initial condition in the state space and for all possible values of the uncertain parameter vector. Finally, the simulation results demonstrate the validity of the proposed method.     

Pseudo‐R 2’s in the ordinal probit model*

This paper presents an analysis of the combining mechanism for status information postulated by the mathematical formulation of the theory of status characteristics and expectation states. Six lemmas on the basic features of the combining mechanism are derived from the formulation and discussed. Further, four theorems that illustrate the implications of the particular combining mechanism for power and prestige orders are presented and proven.     

Global well-posedness for an inhomogeneous LSW–model in unbounded domains

The LSW–theory of domain coarsening describes the evolution of the size distribution of a system of particles evolving by diffusional mass exchange to reduce their total surface area. We prove existence and uniqueness of solutions to an inhomogeneous extension of the LSW–model in unbounded domains. This model arises naturally as a homogenization limit of the underlying free boundary problem in the case of a system of particles for which the screening length (the effective range of particle interactions) is smaller than the system size. The crucial ingredients in the analysis are, first, to establish the screening property by showing that the corresponding Greens function decreases exponentially over the relevant distances. Second, we have to control the mass fluxes between different regions to prevent aggregation of mass in few particles which would result in blow–up of the solution.Mathematics Subject Classification (2000):82C26, 35Q72, 35D05Received: 16, December 2001     

Numerical modeling of seismic and acoustic-gravity waves propagation in an “Earth-Atmosphere” model in the presence of wind in the air

In this paper, an effective numerical algorithm for 2.5D seismic and acoustic-gravitational wave propagation is applied to a combined “Earth-Atmosphere” model in the presence of wind in the air. Seismic wave propagation in an elastic half-space is described by a system of first-order dynamic equations of elasticity theory. The propagation of acoustic-gravitational waves in the atmosphere in the presence of wind is described by the linearized Navier-Stokes equations. The algorithm is based on the integral Laguerre transform with respect to time, the finite integral Fourier transform with respect to a spatial coordinate combined with a finite difference method for the reduced problem.