An efficient implementation of the equilibrium algorithm for housing markets with duplicate houses

We propose an asymptotically optimal implementation of the equilibrium algorithm for housing markets with duplicate houses and strict preferences. It is based on Tarjan?s depth-first search algorithm for strongly connected components of a digraph.     

An economic agent-based model of coupled housing and land markets (CHALMS)

This paper describes a spatially disaggregated, economic agent-based model of urban land use, which is named for its innovative feature of coupled housing and land markets (CHALMS). The three types of agents—consumer, farmer and developer—all make decisions based on underlying economic principles, and heterogeneity of both individuals and the landscape is represented. CHALMS simulates the conversion of farmland to housing development over time, through the actions of the agents in the land and housing markets. Land and building structures in the housing bundle are treated explicitly, so the model can represent the effects of land and housing prices on housing density over time. We use CHALMS to simulate the dynamics of land-use changes as a representative suburban area grows. The presence of agent and landscape heterogeneity, stochastic processes, and path dependence require multiple model runs, and the expression of spatial dispersion of housing types, overall housing density, and land prices over time in terms of the most likely, or ‘average’, patterns. We find that CHALMS captures both the general tendency for diminishing population density at greater distances from the center city, and dispersed leapfrog patterns of development evident in most suburban areas of the US.     

A multi-agent model of urban processes: Modelling relocation processes and price setting in housing markets

This paper introduces an agent-based micro-simulation model of housing market processes. The model describes aggregate housing market developments, such as price and turnover, as the outcome of households’ decisions to search for a new dwelling, accept an offered dwelling or sell their dwelling. An important feature of the model is that households’ decisions are based on perceptions of housing market probabilities. Households update these perceptions based on observed bargaining outcomes in the market. The model was tested in a simulation experiment and appeared to respond plausibly to different market settings in terms of prices and households’ perception of the market.     

分散固定阻塞零点与分散强镇定

研究多通道系统的分散强镇定问题.对集中控制系统的阻塞零点概念提出一种推广的定义.在此基础上,对分散控制系统引入了关于通道及系统的分散固定阻塞零点等概念,揭示出分散系统的阻塞零点与反馈结构的关系.利用这种关系,在比已有结论更弱的假定下,给出了可分散强镇定的充分必要条件及相应控制器求解的一般步骤.     

非线性大系统的分散线性化与分散控制

将非线性控制系统的精确线性化方法应用于非线性大系统,提出了非线性大系统 的分散线性化方法,并得到了非线性系统可分散线性化的充要条件.按照这个方法,可将难度 较大的一类非线性大系统分散控制器的设计转化为易于处理的线性大系统分散控制器的设 计.在得到该线性大系统的分散控制器后,可通过分散坐标变换的逆变换将线性大系统的控 制器变换为原非线性大系统的控制器.同时,控制器的分散性保持不变.该方法明显地降低了 该类非线性大系统分散控制器的设计难度.     

Decentralized control and communication

In this paper, the past and current issues involved in the design of decentralized networked control systems are reviewed. The basic models of interconnected systems described as continuous-time linear time-invariant systems in the time domain serve as a framework for the inclusion of communication channels in the decentralized feedback loop. The I/O-oriented models and the interaction oriented models with disjoint subsystems and interactions are distinguished. The overview is focused on packet dropouts, transmission delays, and quantization effects which are included in the time-driven design of feedback loop components. Single- and multiple-packet transmissions are considered in this contents. The design of decentralized state feedback gain matrices with delayed feedback uses the methodology of sampled-data feedback design for continuous-time systems, while the decentralized H_∞ quantizer design is based on the static output controller. The Liapunov stability approach results in computationally efficient decentralized control design strategies described by using linear matrix inequalities.     

Economic inequality and the environment

This paper analyzes the relationship between the level of income inequality and the quality of the environment (as measured by sulfur dioxide air pollution levels) in the US for the years 1947–1996, using a vector error correction model. We find that air pollution levels do appear to be negatively significantly correlated with the level of income inequality (as measured by the Gini coefficient), that is, income inequality decreases as pollution increases. Furthermore, the quality of the environment appears to affect different portions of the observed income graduation differently. For the lowest two quintiles, higher pollution is associated with an increase in their share of total US income, while for the highest quintile, higher pollution is associated with a decrease in their share of total US income.     

Managing the Decentralized IT Organization

The growing trend to decentralize the IT function and move applications development to business units is often controlled by top management. A coordinated set of best practices helps IT managers take charge of change, position the IT organization as both a vendor of development services and a provider of vital infrastructure services, and ensure a logical career-enhancing structure for IT professionals.     

Note on the Carleman’s inequality and Hardy’s inequality

In this article, using the properties of power mean and induction, new strengthened Carleman’s inequality and Hardy’s inequality are obtained. We also give an answer to the conjectures proposed by X. Yang in the literature Yang (2001) [5].     

Relative risk aversion and wealth dynamics

As a follow-up to the work of Chen and Huang [S.-H. Chen, Y.-C. Huang, Risk preference, forecasting accuracy and survival dynamics: simulations based on a multi-asset agent-based artificial stock market, Working Paper Series 2004-1, AI-ECON Research Center, National Chengchi University, 2004; S.-H. Chen, Y.-C. Huang, Risk preference and survival dynamics, in: T. Terano, H. Kita, T. Kaneda, K. Arai, H. Deghchi (Eds.), Agent-Based Simulation: From Modeling Methodologies to Real-World Applications, Springer Series on Agent-Based Social Systems, vol. 1, 2005, pp. 135-143], this paper continues to explore the relationship between wealth share dynamics and risk preferences in the context of an agent-based multi-asset artificial stock market. We simulate a multi-asset agent-based artificial stock market composed of heterogeneous agents with different degrees of relative risk aversion. As before, we find that the difference in risk aversion and the resultant saving behavior are the primary forces in determining the survivability of agents. In addition to the stability of the saving behavior, the level of the saving rate also plays a crucial role. The agents with stable saving behavior, e.g., the log-utility agents, may still become extinct because of their low saving rates, whereas the agents with unstable saving behavior may survive because of their high saving rates, implied by their highly risk-averse preferences.     

Decentralized blocking zeros and the decentralized strongstabilization problem

This paper is concerned with a new system theoretic concept, decentralized blocking zeros, and its applications in the design of decentralized controllers for linear time-invariant finite-dimensional systems. The concept of decentralized blocking zeros is a generalization of its centralized counterpart to multichannel systems under decentralized control. Decentralized blocking zeros are defined as the common blocking zeros of the main diagonal transfer matrices and various complementary transfer matrices of a given plant. As an application of this concept, we consider the decentralized strong stabilization problem (DSSP) where the objective is to stabilize a plant using a stable decentralized controller. It is shown that a parity interlacing property should be satisfied among the real unstable poles and real unstable decentralized blocking zeros of the plant for the DSSP to be solvable. That parity interlacing property is also sufficient for the solution of the DSSP for a large class of plants satisfying a certain connectivity condition. The DSSP is exploited in the solution of a special decentralized simultaneous stabilization problem, called the decentralized concurrent stabilization problem (DCSP). Various applications of the DCSP in the design of controllers for large-scale systems are also discussed     

Decentralized processing of documents

The term document processing covers the creation, modification, formatting, output and interchange of documents. This article describes the situation in the area of document processing today and discusses the requirements for future document processing systems. The current state of the International Standards in this area is presented.     

Endogenous rise and collapse of housing price: An agent-based model of the housing market

On the basis of interviews with local real estate agents, this study develops an agent-based model of housing market to determine the cause of rise and collapse of US housing price during the years immediately preceding the US financial crisis (2007–2009). We study the key factors affecting housing price volatility, such as lenient financing and speculation. The dynamic simulation findings in the study show in concrete terms how lenient lending practices combined with speculation can lead to increased volatility in housing price, including sharp rises immediately followed by collapses. The exploratory work in this study will contribute to the understanding of the causes of housing bubbles and inform policy decisions.     

Inference-Based Ambiguity Management in Decentralized Decision-Making: Decentralized Control of Discrete Event Systems

Decentralized decision-making requires the interaction of various local decision-makers in order to arrive at a global decision. Limited sensing capabilities at each local site can create ambiguities in a decision-making process at each local site. We argue that such ambiguities are of differing gradations. We propose a framework for decentralized decision-making (applied to decentralized control in particular) that allows computation of such ambiguity gradations and utilizes their knowledge in arriving at a global decision. Each local decision is tagged with a certain grade or level of ambiguity, with zero being the minimum ambiguity level. A global decision is taken to be the same as a ldquowinningrdquo local decision, i.e., one having the minimum level of ambiguity. The computation of an ambiguity level for a local decision requires an assessment of the self-ambiguities as well as the ambiguities of the others, and an inference based upon such knowledge. For the existence of a decentralized supervisor, so that for each controllable event the ambiguity levels of all winning disablement or enablement decisions are bounded by some number N (such a supervisor is termed N-inferring), the notion of N-inference observability is introduced. We show that the conjunctive-and-permissive (C&P) V disjunctive-and-antipermissive (D&A) co-observability is the same as the zero-inference observability, whereas the conditional C&P V D&A co-observability is the same as the unity-inference observability. We also present examples of higher order inference-observable languages. Our framework does not require the existence of any a priori partition of the controllable events into permissive/antipermissive sets, nor does it require a global control computation based on conjunction/disjunction of local decisions, exhibiting that our ambiguity-based approach is more efficient.     

Decentralized control: Status and outlook

This paper reviews state of the art in the area of decentralized networked control systems with an emphasis on event-triggered approach. The models or agents with the dynamics of linear continuous-time time-invariant state-space systems are considered. They serve for the framework for network phenomena within two basic structures. The I/O-oriented systems as well as the interaction-oriented systems with disjoint subsystems are distinguished. The focus is laid on the presentation of recent decentralized control design and co-design methods which offer effective tools to overcome specific difficulties caused mainly by network imperfections. Such side-effects include communication constraints, variable sampling, time-varying transmission delays, packet dropouts, and quantizations. Decentralized time-triggered methods are briefly discussed. The review is deals mainly with decentralized event-triggered methods. Particularly, the stabilizing controller–observer event-based controller design as well as the decentralized state controller co-design are presented within the I/O-oriented structures of large scale complex systems. The sampling instants depend in this case only on a local information offered by the local feedback loops. Minimum sampling time conditions are discussed. Special attention is focused on interaction-oriented system architecture. Model-based approach combined with event-based state feedback controller design is presented, where the event thresholds are fully decentralized. Finally, several selected open decentralized control problems are briefly offered as recent research challenges.     

Agents and markets

Autonomous agents are intelligent software programs. Typically, agents are situated in an environment. Repeatedly, they sense their environment, engage in some decision making whereby they select actions, and execute their actions, which, in turn, impact their environment. Moreover, in most cases, the environment contains a number of such agents whose actions typically mutually affect one another. This interdependence arises because the different agents, with their own aims and objectives, must operate in a common environment that has finite resources and capabilities. Depending on the dependency's nature, several different types of social interaction occur between the agents, including cooperation, coordination, and negotiation. Autonomous agents are becoming active participants in marketplaces. We present a study on the interactions between autonomous agents and markets.     

利用MBD模式实现分布式网络管理

现代网络的发展迫切要求在以设备 为中心的分布式网络管理取代平台集中式的网络管理，一些灵活、高效的分布式网管策略由此发展起来。将简要介绍几种具有代表性的分布式策略，并就其中的MBD模型加工从工作原理到其优越性以详细地讨论。     

分散干扰解耦的相容性*

本文讨论分散控制干扰解耦中的结构(A,B_i)不变子空间。发现了它的一个新的必要条件——相容条件,讨论了相容条件的基本性质,并且由此证明了第一个结构(A,B_i)不变子空间的充分必要条件。     

Decentralized control of vehicle formations

This paper investigates a method for decentralized stabilization of vehicle formations using techniques from algebraic graph theory. The vehicles exchange information according to a pre-specified communication digraph, G. A feedback control is designed using relative information between a vehicle and its in-neighbors in G. We prove that a necessary and sufficient condition for an appropriate decentralized linear stabilizing feedback to exist is that G has a rooted directed spanning tree. We show the direct relationship between the rate of convergence to formation and the eigenvalues of the (directed) Laplacian of G. Various special situations are discussed, including symmetric communication graphs and formations with leaders. Several numerical simulations are used to illustrate the results.