Stabilization irrespective of bounds of uncertain variations for linear uncertain systems with delays

In this study, the stabilizability irrespective of the bounds of uncertain parameters and time delays is investigated for linear uncertain delay systems. For uncertain systems without delays, a linear time-varying or time-invariant uncertain system has been shown to be stabilizable independent of the bounds of uncertain variations if and only if the system has a particular geometric configuration called an antisymmetric stepwise configuration (ASC) or a generalized antisymmetric stepwise configuration (GASC), respectively. In this study, fundamental approaches to investigating the stabilizability of delay systems with specific uncertainty structures such as ASCs or GASCs are presented. For a class of 3-dimensional systems, it is shown here that if a linear time-varying or time-invariant uncertain delay system has an ASC or a GASC, respectively, then the system can be stabilized, however large the given bounds of delays and uncertain parameters might be.     

Production management as an ordering of multiple qualities: negotiating the quality of coffee in Timor-Leste

ABSTRACT

The emergence of close-knit global–local links in many agro-food production systems has necessitated rigorous coordination between the key stakeholders to ensure that quality and safety standards are met. To analyze this new supply chain configuration, agro-food studies inspired by convention theory have drawn significant attention to the plurality of quality conventions. In the literature specifically focusing on the inter-relationships between multiple quality conventions, the ways of interpreting a specific value orientation are perceived to have important implications. This view may lead to a questioning of how the configuration of multiple quality conventions can be stabilized if conflicting justification principles are not easily reconciled. The argument is further connected with an examination of situated plurality in a particular context, focusing on how the boundary among multiple quality conventions is stabilized on the ground. In this paper, through a case analysis of coffee quality management in Timor-Leste, I attempt to demonstrate that commoditization is to be reformulated as the process in which the qualification of objects and regularization of action are constituted through the differentiation of consumable quality as generality from heterogeneous cultural elements as particularity.     

Inverting microwell array chip for the cultivation of human induced pluripotent stem cells with controlled aggregate size and geometrical arrangement

We present a novel cell culture chip, namely, “inverting microwell array chip,” for cultivation of human induced pluripotent stem cells. The chip comprises a lower hydrogel microwell array and an upper polystyrene culture surface. We demonstrate the formation of uniform cellular aggregates in the microwell array, and after inversion, a culture with controlled aggregate size and geometrical arrangement on the polystyrene surface. Here, we report effects of cell concentrations on a cultivation sequence in the chip.