Accommodating repair actions into gas turbine prognostics

Elements of gas turbine degradation, such as compressor fouling, are recoverable through maintenance actions like compressor washing. These actions increase the usable engine life and optimise the performance of the gas turbine. However, these maintenance actions are performed by a separate organization to those undertaking fleet management operations, leading to significant uncertainty in the maintenance state of the asset. The uncertainty surrounding maintenance actions impacts prognostic efficacy. In this paper, we adopt Bayesian on-line change point detection to detect the compressor washing events. Then, the event detection information is used as an input to a prognostic algorithm, advising an update to the estimation of remaining useful life. To illustrate the capability of the approach, we demonstrated our on-line Bayesian change detection algorithms on synthetic and real aircraft engine service data, in order to identify the compressor washing events for a gas turbine and thus provide demonstrably improved prognosis

Is Political Risk Company-Specific? The Market Side of the Yukos Affair

The Yukos affair, a high-profile story of the state-led assault on a private Russian company, provides an excellent opportunity for an inquiry into the nature of company-specific political risks in emerging markets. News associated primarily with law enforcement agencies’ actions against company’s managers, not formally related to the company itself, caused significant negative abnormal returns for Yukos. The results are robust and not driven by a few major events, such as the arrests of Yukos’ top managers and shareholders. Stocks of less transparent private Russian companies have been more sensitive to Yukos-related events, especially employee-related charges by law enforcement agencies. The situation was different for less transparent government-owned companies such as the world-largest natural gas producer Gazprom: they appear to be significantly less sensitive to these events. Actions of regulatory agencies have had predominantly industry-wide impact, whereas law-enforcement agencies’ actions affected shares of large private companies, especially those privatized in the notorious loans-for-shares privatization auctions.http://deepblue.lib.umich.edu/bitstream/2027.42/40158/3/wp772.pd

Beliefs and actions in the trust game: creating instrumental variables to estimate the causal effect

In many economic contexts, an elusive variable of interest is the agent's expectation about relevant events, e.g. about other agents' behavior. Recent experimental studies as well as surveys have asked participants to state their beliefs explicitly, but little is known about the causal relation between beliefs and other behavioral variables. This paper discusses the possibility of creating exogenous instrumental variables for belief statements, by shifting the probabilities of the relevant events. We conduct trust game experiments where the amount sent back by the second player (trustee) is exogenously varied by a random process, in a way that informs only the �first player (trustor) about the realized variation. The procedure allows detecting causal links from beliefs to actions under plausible assumptions. The IV estimates indicate a signi�ficant causal effect, comparable to the connection between beliefs and actions that is suggested by OLS analyses

Event Identification as a Decision Process with Non-linear Representation of Text

We propose scale-free Identifier Network(sfIN), a novel model for event identification in documents. In general, sfIN first encodes a document into multi-scale memory stacks, then extracts special events via conducting multi-scale actions, which can be considered as a special type of sequence labelling. The design of large scale actions makes it more efficient processing a long document. The whole model is trained with both supervised learning and reinforcement learning.Comment: 8 pages, 8 figure

Tree-Maiming to Crop Destruction: Considering a Re-Emerging Repertoire

Property destruction has been a key part of the protest repertoire in Western Europe (and further afield) throughout history. Such acts have represented the physical manifestation of opposition to perceived inequalities in society, ranging from actions of groups such as the Luddites through to spontaneous food riots. Although these actions can be portrayed as unthinking and solely focused on destruction, it is important to consider underlying claim being made through the action. This paper draws on a catalogue of protest events to consider the wave of crop trashing that took place in the UK in the late 1990s and early 2000s. The aim is to locate these actions in the broader tradition of destruction targeting flora to determine the extent to which these actions can be seen as representing a traditional form of action and consider the degree of continuity in the underlying motives