Gather-and-broadcast frequency control in power systems

We propose a novel frequency control approach in between centralized and distributed architectures, that is a continuous-time feedback control version of the dual decomposition optimization method. Specifically, a convex combination of the frequency measurements is centrally aggregated, followed by an integral control and a broadcast signal, which is then optimally allocated at local generation units. We show that our gather-and-broadcast control architecture comprises many previously proposed strategies as special cases. We prove local asymptotic stability of the closed-loop equilibria of the considered power system model, which is a nonlinear differential-algebraic system that includes traditional generators, frequency-responsive devices, as well as passive loads, where the sources are already equipped with primary droop control. Our feedback control is designed such that the closed-loop equilibria of the power system solve the optimal economic dispatch problem

Forging success : Soviet managers and accounting fraud, 1943 to 1962

Attempting to satisfy their political masters in a target-driven culture, Soviet managers had to optimize on many margins simultaneously. One of these was the margin of truthfulness. False accounting for the value of production was apparently widespread in some branches of the economy and at some periods of time. A feature of accounting fraud was that cases commonly involved the aggravating element of conspiracy. The paper provides new evidence on the nature and extent of accounting fraud; the scale and optimal size of conspiratorial networks; the authorities’ willingness to penalize it and the political and social factors that secured leniency; and inefficiency in the socialist market where managers competed for political credit

Forging Success: Soviet Managers and Accounting Fraud, 1943 to 1962

Attempting to satisfy their political masters in a target-driven culture, Soviet managers had to optimize on many margins simultaneously. One of these was the margin of truthfulness. False accounting for the value of production was apparently widespread in some branches of the economy and at some periods of time. A feature of accounting fraud was that cases commonly involved the aggravating element of conspiracy. The paper provides new evidence on the nature and extent of accounting fraud; the scale and optimal size of conspiratorial networks; the authorities’ willingness to penalize it and the political and social factors that secured leniency; and inefficiency in the socialist market where managers competed for political creditAccounting Fraud, Performance-Based Incentives, Political Markets, Soviet Economy

Enabling rapid and cost-effective creation of massive pervasive games in very unstable environments

Pervasive gaming is a new form of multimedia entertainment that extends the traditional computer gaming experience out into the real world. Through a combination of personal devices, positioning systems and other sensors, combined with wireless networking, a pervasive game can respond to player's movements and context and enable them to communicate with a game engine and other players. We review our recent deployment examples of pervasive games in order to explain their distinctive characteristics as wireless ad-hoc networking applications. We then identify the network support challenges of scaling pervasive games to include potentially mass numbers of players across extremely heterogeneous and unreliable networks. We propose a P2P overlay capable of storing large amount of game related data, which is the key to combating the loss of coverage and potential dishonesty of players. The proposed protocol decreases the deployment costs of the gaming infrastructure by self organization and utilizing storage space of users' devices. We demonstrate scalability and increased availability of data offered by the proposed protocol in simulation based evaluatio

What are the factors affecting information quality in supply chains?

This study answered what factors affect information quality in supply chains. It identified the factors leading to information quality, the association between these factors and the organisational context, which moderates the relationship between these factors and information quality. Many of these moderating factors were found to result from cultural differences

Using current uptime to improve failure detection in peer-to-peer networks

Peer-to-Peer (P2P) networks share computer resources or services through the exchange of information between participating nodes. These nodes form a virtual network overlay by creating a number of connections with one another. Due to the transient nature of nodes within these systems any connection formed should be monitored and maintained to ensure the routing table is kept up-to-date. Typically P2P networks predefine a fixed keep-alive period, a maximum interval in which connected nodes must exchange messages. If no other message has been sent within this interval then keep-alive messages are exchanged to ensure the corresponding node has not left the system. A fixed periodic interval can be viewed as a centralised, static and deterministic mechanism; maintaining overlays in an predictable, reliable and non-adaptive fashion. Several studies have shown that older peers are more likely to remain in the network longer than their short-lived counterparts. Therefore using the distribution of peer session times and the current age of peers as key attributes, we propose three algorithms which allow connections to extend the interval between successive keep-alive messages based upon the likelihood that a corresponding node will remain in the system. By prioritising keep-alive messages to nodes that are more likely to fail, our algorithms reduce the expected delay between failures occurring and their subsequent detection. Using extensively empirical analysis, we analyse the properties of these algorithms and compare them to the standard periodic approach in unstructured and structured network topologies, using tracedriven simulations based upon measured network data. Furthermore we also investigate the effect of nodes that misreport their age upon our adaptive algorithms and detail an efficient keep-alive algorithm that can adapt to the limitations network address translation devices

Quantitative Methods for Economics and Finance

This book is a collection of papers for the Special Issue “Quantitative Methods for Economics and Finance” of the journal Mathematics. This Special Issue reflects on the latest developments in different fields of economics and finance where mathematics plays a significant role. The book gathers 19 papers on topics such as volatility clusters and volatility dynamic, forecasting, stocks, indexes, cryptocurrencies and commodities, trade agreements, the relationship between volume and price, trading strategies, efficiency, regression, utility models, fraud prediction, or intertemporal choice