Anisoara Calinescu

• University of Oxford

In financial credit networks, prepayments enable a firm to settle its debt obligations ahead of an agreed-upon due date. Prepayments have a transformative impact on the structure of networks, influencing the financial well-being (utility) of individual firms. This study investigates prepayments from both theoretical and empirical perspectives. We f...

A key challenge in interpretability is to decompose model activations into meaningful features. Sparse autoencoders (SAEs) have emerged as a promising tool for this task. However, a central problem in evaluating the quality of SAEs is the absence of ground truth features to serve as an evaluation gold standard. Current evaluation methods for SAEs a...

In the last few years, economic agent-based models have made the transition from qualitative models calibrated to match stylised facts to quantitative models for time series forecasting, and in some cases, their predictions have performed as well or better than those of standard models (see, e.g. Poledna et al. (2023a); Hommes et al. (2022); Pichle...

In financial credit networks, prepayments enable a firm to settle its debt obligations ahead of an agreed-upon due date. Prepayments have a transformative impact on the structure of networks, influencing the financial well-being (utility) of individual firms. This study investigates prepayments from both theoretical and empirical perspectives. We f...

In agent-based simulations, synthetic populations of agents are commonly used to represent the structure, behaviour, and interactions of individuals. However, generating a synthetic population that accurately reflects real population statistics is a challenging task, particularly when performed at scale. In this paper, we propose a multi objective...

Financial exchanges across the world use limit order books (LOBs) to process orders and match trades. For research purposes it is important to have large scale efficient simulators of LOB dynamics. LOB simulators have previously been implemented in the context of agent-based models (ABMs), reinforcement learning (RL) environments, and generative mo...

Developing a generative model of realistic order flow in financial markets is a challenging open problem, with numerous applications for market participants. Addressing this, we propose the first end-to-end autoregressive generative model that generates tokenized limit order book (LOB) messages. These messages are interpreted by a Jax-LOB simulator...

Agent-based models (ABMs) are a promising approach to modelling and reasoning about complex systems, yet their application in practice is impeded by their complexity, discrete nature, and the difficulty of performing parameter inference and optimisation tasks. This in turn has sparked interest in the construction of differentiable ABMs as a strateg...

Agent-based modelling (ABMing) is a powerful and intuitive approach to modelling complex systems; however, the intractability of ABMs' likelihood functions and the non-differentiability of the mathematical operations comprising these models present a challenge to their use in the real world. These difficulties have in turn generated research on app...

Digital Twin was introduced over a decade ago, as an innovative all-encompassing tool, with perceived benefits including real-time monitoring, simulation, optimisation and accurate forecasting. However, the theoretical framework and practical implementations of digital twin (DT) are yet to fully achieve this vision at scale. Although an increasing...

Digital twin technology has been regarded as a beneficial approach in supply chain development. Different from traditional digital twin (temporal dynamic), supply chain digital twin is a spatio-temporal dynamic system. This paper explains what is 'twined' in supply chain digital twin and how to 'twin' them to handle the spatio-temporal dynamic issu...

Significance We develop the mathematical analogy between financial trading strategies and biological species and show how to apply standard concepts from ecology to financial markets. We analyze the interactions of stereotypical trading strategies in ecological terms, showing that they can be competitive, predator–prey, or mutualistic, depending on...

Digital Twin was introduced over a decade ago, as an innovative all-encompassing tool, with perceived benefits including real-time monitoring, simulation and forecasting. However, the theoretical framework and practical implementations of digital twins (DT) are still far from this vision. Although successful implementations exist, sufficient implem...

Standard approaches to the theory of financial markets are based on equilibrium and efficiency. Here we develop an alternative based on concepts and methods developed by biologists, in which the wealth invested in a financial strategy is like the population of a species. We study a toy model of a market consisting of value investors, trend follower...

Meeting the security requests in transportation is nowadays a must. The intelligent transport systems (ITSs) represent the support for addressing such a challenge, due to their ability to make real-time adaptive decisions. We propose a new variant of the travelling salesman problem (TSP) integrating security constraints inspired from ITSs. This opt...

This paper uses a multiple case-study methodology to investigate complexity transfer (CT) in manufacturing supplier-customer systems, leading to a new model of complexity transfer. An entropic-related complexity measure is applied to three supplier-customer systems, internally within each organisation and at their supplier-customer interface. The r...

Modern supply chains security solutions need to also solve transport security. Greenhouse gas (GHG) emissions have a direct influence on the structure and behaviour of supply chains. The more complex the supply chains, the more critical these two dimensions become. This paper introduces a mathematical model for computing the risk associated with Gr...

The purpose of this paper is to advance the understanding of the conditions that give rise to flash crash contagion, particularly with respect to overlapping asset portfolio crowding. To this end, we designed, implemented, and assessed a hybrid micro–macro agent-based model, where price impact arises endogenously through the limit order placement a...

The purpose of this paper is to advance the understanding of the conditions that give rise to flash crash contagion, particularly with respect to overlapping asset portfolio crowding. To this end, we designed, implemented, and assessed a hybrid micro-macro agent-based model, where price impact arises endogenously through the limit order placement a...

Todays global financial marketplace is best understood as a complex network of interacting market systems, in which events of world-wide significance unfold on timescales that are barely within the ability of humans to comprehend. Many researchers have concluded that the dynamics of networked market systems are better under-stood as complex adaptiv...

The robustness, resilience and security of supply chain transportation is an active research topic, as it directly determines the overall supply chain resilience and security. In this paper, we propose a theoretical model for the transportation problem within a two-stage supply chain network with security constraints called the Secure Supply Chain...

Sustainability is of course vogue as well as being intentionally resource-conserving; yet despite its popularity and interest from the academic community, many of its characteristics still remain elusive. Its interpretation, management and cost seem only partially understood, for example, how can sustainability effectiveness best be measured? How d...

The purpose of this paper is to contribute to the theoretical and applied understanding of complexity transfers in supply chains through cross-case analysis of seven in-depth case studies conducted in UK manufacturing companies in the last ten years. An informationtheoretic methodology was followed in all cases, using entropy as a measure of comple...

Within the supply chain context, schedule instability is caused by revisions to forecast demand from customers, problems with scheduled deliveries from suppliers, and disruptions to internal production. Supply chain partners attempt to address schedule instability by regular exchanges of information flows on current demand and delivery forecasts. H...

This chapter investigates manufacturing rescheduling of customised production and compares the results with those found for commodity production in earlier research by the authors. The hybrid rescheduling algorithms presented in this chapter were obtained by combining two key rescheduling-related elements found in the literature (a) rescheduling cr...

Algorithmic trading (AT) strategies aim at executing large orders discretely, in order to minimize the order's impact, whilst also hiding the traders' intentions. Most AT evaluation methods range from running the AT strategies against historical data (back testing) to evaluating them on simulated markets. The contribution of the work presented in t...

This paper presents the findings of a study with a Unilever bottle-filling plant and its key bottle supplier, ALPLA. The purpose of this paper is to investigate the complexity associated with before and after integration. The nature of the complexity alters as the supplier-customer relationship changes, in this case from pre-integration to post-int...

This paper revisits and extends the structural and dynamic complexity measures of manufacturing systems, which are based on an information-theoretic interpretation of the amount of information that is needed to describe the state of a manufacturing system. In this paper, a generic manufacturing system is modelled as a set of interacting resources a...

This chapter investigates manufacturing rescheduling of customised production and compares the results with those found for commodity production in earlier research by the authors. The hybrid rescheduling algorithms presented in this chapter were obtained by combining two key rescheduling-related elements found in the literature (a) rescheduling cr...

The main contribution of this paper is the demonstration that, contrary to conventional thinking, a measurable increase in the operational complexity of the production scheduling function between two companies can occur following closer supply chain integration. The paper presents the practical application of previous work carried out and validated...

Networked systems, natural or designed, have always been part of life. Their sophistication degree and complexity have increased through either natural evolution or technological progress. However, recent theoretical results have shown that a previously unexpected number of different classes of networks share similar network architectures and unive...

The primary objective of this paper is to compare five rescheduling strategies according to their effectiveness in reducing entropic-related complexity arising from machine breakdowns in manufacturing systems. Entropic-related complexity is the expected amount of information required to describe the state of the system. Previous case studies carrie...

1 Modern manufacturing supply networks are challenged by demands for flexible responses to demanding customers who require rapid delivery of customized products. Traditional methods of simulation and optimization do not capture enough of the complexity of information flow and agent behaviour to provide adequate means of meeting the challenges to un...

Prospective readers can quickly determine whether a document is relevant to their information need if the significant phrases (or keyphrases) in this document are provided. Although keyphrases are useful, not many documents have keyphrases assigned to them, and manually assigning keyphrases to existing documents is costly. Therefore, there is a nee...

Autonomic computing undoubtedly represents the solution for dealing with the complexity of modern computing systems, driven by ever increasing user needs and requirements. The design and management of autonomic computing systems must be performed both rigorously and carefully. Valuable lessons in this direction can be learned from biological and su...

Even structurally simple supplier–customer systems can be operationally complex. This operational complexity can be colloquially defined as the uncertainty associated with managing the dynamic variations, in time or quantity, across information and material flows at the supplier–customer interface. This paper proposes a means of measuring the infor...

In recent years, Supply Chain Management has gained greater attention from academics and managers concerned to improve process efficiencies; and take best advantage of information technology and inter-organizational networks and relationships. This book brings together leading experts to provide a reference point for developments and issues in the...

Information-theoretic modelling of manufacturing organizations and their supply chains has led to the development of measures of manufacturing complexity. The measures include assessment of the structural, dynamic and decision-making complexity associated with the processing and movement of material and information around a manufacturing system. A...

In a dynamic environment such as the supply chain, even basic supplier-customer systems with structurally simple information and material flow formations have a tendency to exhibit operational complexity. The operational complexity of supplier-customer systems is primarily characterised by the uncertainty of the system. As the operational complexit...

The operational complexity of supply chains can vary with the volatility of customer demands, reliability of material supply, predictability of internal performance, and the effectiveness of management and control policies in place. Based on insights from real- life case studies, this paper explores some practical policies available to organisation...

Information variety and uncertainty are the key elements of complexity in manufacturing systems. An information-theoretic model based on entropy is proposed here. The model shows the interaction between the scheduling function and the production function, which provides a realistic framework for the control of complexity in manufacturing systems. T...

The theory `keep it simple' is universally known, but too many companies apply it by exporting their complexity and costs to their own suppliers and customers. In the days of supply-chain competition, this has become a dangerous strategy. Effective management of information flows allows control of the passing of information complexity through the s...

Information transfer within supply chains is often complex. The static and dynamic characteristics as well as the level of predictability and control of supply chain information contribute to the overall level of complexity within the system. This paper reports on the progress of a project in collaboration with a major UK company and one of its sup...

Previous work in manufacturing has identified complexity as a relevant topic in this field. However, there is a high diversity of opinions on what complexity is, why it should be measured and how this can be done. This paper aims to contribute to a better understanding of manufacturing complexity and of the relationship between the system’s complex...

Manufacturers are under many pressures to change the way they do things. There are the pressures to reduce product development times, to provide customised products within a volume manufacturing environment, to make frequent deliveries and hold low levels of stock. All these are laudable aims, but achieving them in an orderly manner is not easy. Wh...

This paper describes how modelling and simulation are used in a case study which assesses the complexity of a manufacturing system and its effect on planning and scheduling reliability in order to identify directions for improvement. The approach chosen, the real system and the structure of the model are briefly presented. A direct relationship bet...

This paper describes the approach adopted in a case-study involving the modelling and simulation of a process-based manufacturing system. The results presented are part of an on-going project on assessing manufacturing complexity and its effect on schedule reliability in manufacturing. We emphasise the importance of a thorough knowledge and underst...

Today’s manufacturing environment is characterised by ever shorter product life cycles, greater product variety and quicker response to customers’ demands. To satisfy these requirements, manufacturers introduce greater flexibility to their process, which may lead to higher levels of complexity and uncertainty. Planning and scheduling are affected b...

This paper proposes the dynamic adaptive configuration of the structure of complex Discrete Event Dynamic Systems depending on particular loading conditions. The main purpose of this new approach is to assure an optimum trade-off between the efficient utilization of resources and the production cost. The system behaviour for a particular task/syste...

In this paper we propose a new, more realistic queueing modelling of Discrete Event Dynamic Systems. Being based on the analysis of the real-world complex discrete event systems, the model allows hot only the exploitation of their inherent parallelism, but also the implementation and the efficiency analysis of deadlock detection/recovery and shared...

In this paper, we study the performance characteristics of different quasi-dynamic and dynamic load balancing strategies for heavily and lightly loaded homogenous distributed systems. For our purpose, we use a M/M/l queuing theoretic model with non-pre-emptive task scheduling with the assumption that the task arrival process at each node is Poisson...

With increasing responsiveness demanded of manufacturers, enhanced flexibility of operations is often advocated. However, the trade-off between costs and benefits of providing flexibility remains little understood. As a prerequisite for establishing this trade-off the implications for management and the control system to ensure that potential flexi...

This paper reports the progress on a project to investigate the information complexity of industrial supply chains. Information complexity, in terms of larger varieties of supply network structure, information characteristics, order characteristics, and control policies within the supply system, can increase the difficulty of co-ordination and infl...

While manufacturers are urged to achieve higher standards of complexity and flexibility, few methods exist to guide them on how to measure these qualities, never mind achieve them. An information theoretic measure of complexity has been developed, extending the work of Frizelle, and is introduced briefly in this paper. This measure forms the basis...

In order to obtain and maintain a competitive advantage in today's marketplace, manufacturing firms must overcome hidden constraints to achieve optimal use of Computer Integrated Manufacturing Information Systems (CIMIS). This calls for an analysis of the enterprise with respect to goals, objectives and capabilities of manufacturing and information...