Observability of Boolean control networks: A unified approach based on the theories of finite automata

The problem on how to determine the observability of Boolean control networks (BCNs) has been open for five years already. In this paper, we propose a unified approach to determine all the four types of observability of BCNs in the literature. We define the concept of weighted pair graphs for BCNs. In the sense of each observability, we use the so-called weighted pair graph to transform a BCN to a finite automaton, and then we use the automaton to determine observability. In particular, the two types of observability that rely on initial states and inputs in the literature are determined. Finally, we show that no pairs of the four types of observability are equivalent, which reveals the essence of nonlinearity of BCNs.Comment: 8 pages, 9 figures, in press in IEEE Transactions on Automatic Control, 201

OverPlotter: A Utility for Herschel Data Processing

The OverPlotter utility is a GUI tool written in Java to support interactive data processing (DP) and analysis for the Herschel Space Observatory within the framework of the Herschel Common Science System (HCSS)(Wieprecht et al 2004). The tool expands upon the capabilities of the TableViewer (Zhang & Schulz 2005), providing now also the means to create additional overlays of sev- eral X/Y scatter plots within the same display area. These layers can be scaled and panned, either individually, or together as one graph. Visual comparison of data with different origins and units becomes much easier. The number of available layers is not limited, except by computer memory and performance. Presentation images can be easily created by adding annotations, labeling layers and setting colors. The tool will be very helpful especially in the early phases of Herschel data analysis, when a quick access to contents of data products is important

Global sourcing of a complex good.

We analyze a firm that produces a final good from multiple intermediates that can each be sourced domestically or from a low-wage country. The model explicitly incorporates that sourcing decisions of intermediates are interdependent. Equilibrium predictions depend crucially on a key modeling assumption - the nature of the trade friction that foreign production has to overcome. If production abroad involves a fixed cost, offshoring one intermediate unambiguously facilitates offshoring of other intermediates. However, if production abroad involves incomplete contracts, offshoring one intermediate almost always makes it more difficult to offshore others. We illustrate that the pattern in prices at which successive automotive parts are imported into the U.S. accords better with the predictions of the incomplete contracting model, except for a few countries with the best governance indicators.