ERP and SCM systems integration: The case of a valve manufacturer in China

Many modern organizations integrate enterprise resource planning (ERP) and supply chain management (SCM) systems, as they work in a complementary fashion. This often results in technical and organizational challenges. Neway, a Chinese organization, recently went through this complex process. This required efficient procurement and management of hardware, software, and human resources for successful completion. The integrated system was found to improve operations, foster a paperless environment, and provide efficient inventory tracking and picking. It also had several tangible benefits, including reduced lead time and improved inventory accuracy. ERP and SCM systems integration is still a novel concept for a Chinese manufacturing organization. Our case study details the organization's experience, identifies challenges that were faced, and describes solutions adopted to overcome them.     

The pollution status of atmospheric carbonyls in a highly industrialized area

The concentrations of 12 carbonyls in ambient air were measured from multiple locations of an urban area in the surroundings of a large industrial complex (August 2004 to September 2005). According to our field study, acetaldehyde (19.5+/-10.6 ppb) and formaldehyde (19.3+/-10.1 ppb) were found to be the two most abundant species followed by propionaldehyde (19.0+/-23.2 ppb), acetone (15.9+/-15.2 ppb) and butyraldehyde (13.0+/-19.8 ppb). An examination of spatial variation patterns of carbonyls, when compared between industrial sites versus non-industrial sites, indicates that the mean values for each site type are statistically insignificant in most cases. In contrast, a comparison of temporal variation patterns indicates a fairly distinctive trend with the relative enhancement during summer (over winter) and/or daytime (over nighttime). The computation of the concentration ratios between some indicative species (e.g., formaldehyde/acetaldehyde and acetaldehyde/propionaldehyde) is unique enough to describe the pollution status of carbonyl species in the study area. Moreover, the relative contribution of several offensive odorous components (e.g., acetaldehyde, propionaldehyde, and butyraldehyde) is fairly strong, while their emissions are suspected to come from a substantial use of ethanol. The results of the present study thus confirm that the acquisition of ambient carbonyl concentration data is fairly useful for distinguishing the pollution status and the associated odor-related impacts.     

Exploration of photoreduction ability of reduced graphene oxide–cadmium sulphide hetero-nanostructures and their intensified activities against harmful microbes

Journal of Materials Science - Fabrication of effective photocatalyst using semiconductors and graphene or reduced graphene oxide has been regarded as one of the most promising task to attenuate...     

Do green supply chain management initiatives impact stock prices of firms?

Although firms have been taking green supply chain management (GSCM) initiatives, it is not known whether they create value for firms. We analyze 104 announcements related to GSCM using an event study, and determine what causes statistically significant gain in stock prices for these firms. Manufacturing firms, firms with high R&D expenses, and early adopters show a strong increase in stock prices on the day of the announcement. At the same time, small firms, firms not well-known for taking green initiatives, as well as firms that are low in growth potential considerably surprise the market when they make such announcements.     

Long-distance axial trapping with Laguerre-Gaussian beams

We show that the axial spread of the focal volume of a tightly focused beam propagating through a glass-water interface is much reduced for Laguerre-Gaussian (LG) modes as compared to the TEM(00) mode. Therefore, use of the LG beam helps in achieving a significant improvement of the axial trapping range in optical tweezers. We demonstrate the use of LG modes to manipulate biological cells from the bottom layer of the medium to the top surface layer. Exposure of the cells to a higher oxygen concentration at the surface layer is used for estimation of the intramembrane oxygen diffusion rate.     

Analysis of partial stability problems using sum of squares techniques

A methodology for algorithmic construction of Lyapunov functions for problems concerning the stability of an equilibrium with respect to part of the system variables is proposed. This methodology utilizes the previously developed sum of squares technique to determine Lyapunov certificates. Conditions for stability with respect to part of the variables are developed that allow for Lyapunov functions to be determined in terms of a sum of squares. Asymptotic stability conditions in terms of sum of squares polynomials are developed for autonomous and non-autonomous systems. An example is presented which demonstrates the methodology and gives insight into the new stability conditions.     

Optimal Controller Switching for Resource-constrained Dynamical Systems

International Journal of Control, Automation and Systems - In this paper, we present the resource-optimal controller switching synthesis for dynamical systems subject to resource constraints....     

Probabilistic model validation for uncertain nonlinear systems

This paper presents a probabilistic model validation methodology for nonlinear systems in time-domain. The proposed formulation is simple, intuitive, and accounts both deterministic and stochastic nonlinear systems with parametric and nonparametric uncertainties. Instead of hard invalidation methods available in the literature, a relaxed notion of validation in probability is introduced. To guarantee provably correct inference, algorithm for constructing probabilistically robust validation certificate is given along with computational complexities. Several examples are worked out to illustrate its use.     

Linear quadratic regulation of systems with stochastic parameter uncertainties

In this paper, we develop a theoretical framework for linear quadratic regulator design for linear systems with probabilistic uncertainty in the parameters. The framework is built on the generalized polynomial chaos theory. In this framework, the stochastic dynamics is transformed into deterministic dynamics in higher dimensional state space, and the controller is designed in the expanded state space. The proposed design framework results in a family of controllers, parameterized by the associated random variables. The theoretical results are applied to a controller design problem based on stochastic linear, longitudinal F16 model. The performance of the stochastic design shows excellent consistency, in a statistical sense, with the results obtained from Monte-Carlo based designs.     

Robust LQR design for systems with probabilistic uncertainty

In this paper, we consider the design of robust quadratic regulators for linear systems with probabilistic uncertainty in system parameters. The synthesis algorithms are presented in a convex optimization framework, which optimize with respect to an integral cost. The optimization problem is formulated as a lower‐bound maximization problem and developed in the polynomial chaos framework. Two approaches are considered here. In the first approach, an exact optimization problem is formulated in the infinite‐dimensional space, which is solved approximately using polynomial‐chaos expansions. In the second approach, an approximate problem is formulated using a reduced‐order model and solved exactly. The robustness of the controllers from these two approaches are compared using a realistic flight control problem based on an F16 aircraft model. Linear and nonlinear simulations reveal that the first approach results in a more robust controller.