Estimating an Endogenous Growth Model with Public Capital and Government Borrowing: U.S. and Germany 1960–1995

The paper presents and estimates an endogenous growth model with publiccapital and government borrowing. Government behavior (tax rates, spending andborrowing) does not follow optimizing rules but is restricted by two fiscalregimes (rules). In the strict fiscal regime government borrowing is used forpublic investment only. In the less strict regime it can also be used forpublic investment and to a certain degree for the debt service. The growthrate differs in our model variants according to which rule is adopted.Moreover, the growth maximizing income tax rate is different from zero. Forthe two relevant fiscal regimes, which correspond roughly to the cases of theU.S. and Germany, the model is estimated by employing time series data from1960.4 to 1992.1 and 1966.1 to 1995.1 respectively. The results suggest anexplanation for the different time paths of economic variables in the Americanand German economies in the post-war period.     

Economic Policy in a Growth Model with Human Capital,Heterogenous Agents and Unemployment

In this paper we present an endogenous growth model with human capital, heterogenous agents and unemployment. Two types of households are considered. One household acquires human capital or skills through education while the other household remains low-skilled. Sustained growth is the result of human capital accumulation which is a function of the existing human capital employed in the educational sector and of public spending for teaching materials. Both households are affected by unemployment and, if so, receive unemployment benefits. The government levies an income tax and uses its revenues to pay unemployment benefits, to finance transfers to the low-skilled household and to finance human capital accumulation. The paper studies growth and welfare effects of economic policy and presents a stability analysis of the model.      

网络视频监控系统中的拥塞避免和控制策略

视频传输的特征是数据量巨大 ,容易对网络产生冲击 ,甚至导致网络的崩溃 ,这就是网络拥塞。文章分析了网络视频监控系统中拥塞产生的原因和带来的影响 ,提出了一种发送端、接收端和中间节点相结合的拥塞避免和控制方案     

Harmonia:Explicit Congestion Notification and Credit-Reservation Transport Converged Congestion Control in Datacenters

Bursty traffic and thousands of concurrent flows incur inevitable network congestion in datacenter networks(DCNs) and then affect the overall performance.Various transport protocols are developed to mitigate the network conges-tion,including reactive and proactive protocols.Reactive schemes use different congestion signals,such as explicit congestion notification (ECN) and round trip time (RTT),to handle the network congestion after congestion arises.However,with the growth of scale and link speed in datacenters,reactive schemes encounter a significant problem of slow responding to congestion.On the contrary,proactive protocols (e.g.,credit-reservation protocols) are designed to avoid congestion before it occurs,and they have the advantages of zero data loss,fast convergence and low buffer occupancy.But credit-reservation protocols have not been widely deployed in current DCNs (e.g.,Microsoft,Amazon),which mainly deploy ECN-based proto-cols,such as data center transport control protocol (DCTCP) and data center quantized congestion notification (DCQCN).And in an actual deployment scenario,it is hard to guarantee one protocol to be deployed in every server at one time.When credit-reservation protocol is deployed to DCNs step by step,the network will be converted to multi-protocol state and will face the following fundamental challenges:1) unfairness,2) high buffer occupancy,and 3) heavy tail latency.Therefore,we propose Harmonia,aiming for converging ECN-based and credit-reservation protocols to fairness with minimal modifi-cation.To the best of our knowledge,Harmonia is the first to address the trouble of harmonizing proactive and reactive congestion control.Targeting the common ECN-based protocols—DCTCP and DCQCN,Harmonia leverages forward ECN and RTT to deliver real-time congestion information and redefines feedback control.After the evaluation,the results show that Harmonia effectively solves the unfair link allocation,eliminating the timeouts and addressing the buffer overflow.     

合力推广 普及理念——专访南鹏科技开发有限公司总经理陈嘉炜先生

厦门南鹏科技开发有限公司为香港南中国科技开发集团在中国内地投资创办的实体企业，总公司注册于厦门市。从上世纪九十年代起，“南中国”已积极开拓内地市场，参与过多项大型会议、视听、演示及控制中心项目的设计、安装及调试，得到了用户的一致认同。由此公司于一九九六年在厦门市投资成立了国内总公司，全面负责“南中国”在内地的业务，逐步建立起内地的业务渠道和服务网络，并已成立了北京、上海、成都、深圳分公司。 南鹏科技目前主要代理的国际知名品牌音视频及通信产品有AMX、AutoPatch、eBeam、ClearOne Russound及Planet Waves等，专业提供多媒体视听演示系统及资讯科技服务，致力于智能中央控制系统的应用和发展，为用户提供会议室及家居视听环境控制系统的设计和安装，倡导全新的智能化环境理念。[编者按]     

RAAR:多媒体流在Internet上传输的一种TCP-Friendly拥塞控制机制

提出了一种接收端的速率自适应算法，称为RAAR。它可以应用于单播传输多媒体数据业务。TCP由于它的遇到单个数据包丢失就减半的特点，造成速率剧烈抖动，不适合传输多媒体数据。UDP由于没有拥塞机制也是不合适的。RAAR在接收端对GAIMD进行了改进，使得它有良好的速率平滑性以及能够与竞争的TCP流公平地分享带宽。RAAR算法比较简单，我们的仿真显示：RAAR的性能明显优于TFRC。由于RAAR没有每包确认机制，而且又是在接收端实现，所以它适合于升级到组播传输多媒体业务。     

Efficiency/Fairness Tradeoffs in Networks with Wireless Components and Transient Congestion

Our work explores the impact of aggressive/conservative congestion control strategies on the fairness and efficiency of reliable transport protocols, in a wired/wireless environment. Based on experiments, we study the behavior of congestion control mechanisms in response to wireless errors, and transient congestion caused by a small number of competing flows. We show that: (i) the traditional TCP algorithm proves to be inadequate in terms of efficiency and fairness when random wireless errors occur in the network and, (ii) an aggressive strategy does not necessarily yield better performance. On the contrary, in the combined presence of transmission errors and transient congestion a conservative strategy appears superior.     

ATM网络ABR业务拥塞控制算法的PI调节器实现

基于速率反馈的流量控制是ATM网络ABR业务标准的流量控制方案。在目前绝大多数拥塞控制方案不能用数学工具进行分析的情况下,本文根据经典控制理论的有关原理,使用一个PI控制器实现了拥塞控制算法。我们对系统进行了分析,证明了此时系统带宽和输入数据速率之间将是无差的;最后通过仿真说明了控制器参数的变化对系统的影响。     

基于延迟抖动分析的TCP友好拥塞控制算法

基于因特网的以UDP为传输协议的实时多媒体数据传输需要在保证实时性和可靠性的基础上,能够与因特网其他服务所使用的TCP协议公平共享有限的带宽。本文采用基于实时传输协议（RTP）和实时传输控制协议（RTCP）的反馈拥塞控制算法,提出一种简单的拥塞控制机制,使UDP数据流能与TCP数据流和平共处;研究了基于速率控制的TCP友好拥塞控制策略-TFRC,分析了其基本机制和关键问题;提出利用延迟抖动作为潜在拥塞信号来改进TFRC的速率控制机制,以适应实时业务低抖动的要求,并通过NS仿真验证了改进的TFRC算法对实时业务的良好性能。     

A combinatorial auction improves school meals in Chile: a case of OR in developing countries

The Chilean State delivers essential meal services at schools for low‐income students. Junta Nacional de Auxilio Escolar y Becas, the institution in charge of covering 1,300,000 children, leases the meal service to private enterprises. We developed an integer linear programming model to assign the meal contracts, in a process known as combinatorial auctions. The resulting model, which is NP‐hard, led to significant improvements in efficiency and also contributed to making the process more transparent. The results are apparent in substantial improvements in quality and coverage of the service, and important savings to the country, which are equivalent to feeding 300,000 children in addition. We developed techniques to solve the combinatorial models and also to analyze and compare multiple scenarios to find robust solutions. For the objective function of this problem, we analyzed several options to consider different kinds of social benefits. In this paper, we describe the problem, the methodology and the results. We also present empirical results based on 6 years of experience. Finally, we discuss the relevance and impact of using operations research in these central issues in developing countries.     

Going Private in Public: A study on shift in behavioral trend using Facebook

The growth of social media has open a new dimension of research in the domain of human Psychology. The data generated by virtue of various available social media platforms is enormous, dynamic, unstructured, imprecise and most of the time uncertain. Facebook has emerged as one of the most successful media of social interaction and thus, contributing a lot to understand various aspects of human behavior. In this paper, a specific and crucial aspect of human nature is being explored- “Going Private in Public”. This aspect deals with some unexploited trend of human psychology and the research work presented in this paper is planned such as to investigate the data that eventually helps to understand this aspect to a great extent. A questionnaire to capture some behavioral trends of Facebook user was designed and filled up using both online and offline mode. The questionnaire included sets of non-identifying demographic questions, Facebook Intensity scale, Social and Emotional Loneliness Scale for Adult, Perceived Stress Scale and NEO-PI-R model. Filling of the forms was made voluntarily and anonymously to avoid any biasing. A total of 312 responses were received and analyzed using Independent-Sample t-test, Cronbach's alpha test, Exploratory factor analysis, and MANOVA etc.     

An Ontology for G2G Collaboration in Public Policy Making,Implementation and Evaluation

This paper concerns the development and use of ontologies for electronically supporting and structuring the highest-level function of government: the design, implementation and evaluation of public policies for the big and complex problems that modern societies face. This critical government function usually necessitates extensive interaction and collaboration among many heterogeneous government organizations (G2G collaboration) with different backgrounds, mentalities, values, interests and expectations, so it can greatly benefit from the use of ontologies. In this direction initially an ontology of public policy making, implementation and evaluation is described, which has been developed as part of the project ICTE-PAN of the Information Society Technologies (IST) Programme of the European Commission, based on sound theoretical foundations mainly from the public policy analysis domain and contributions of experts from the public administrations of four European Union countries (Denmark, Germany, Greece and Italy). It is a ‘horizontal’ ontology that can be used for electronically supporting and structuring the whole lifecycle of a public policy in any vertical (thematic) area of government activity; it can also be combined with ‘vertical’ ontologies of the specific vertical (thematic) area of government activity we are dealing with. In this paper is also described the use of this ontology for electronically supporting and structuring the collaborative public policy making, implementation and evaluation through ‘structured electronic forums’, ‘extended workflows’, ‘public policy stages with specific sub-ontologies’, etc., and also for the semantic annotation, organization, indexing and integration of the contributions of the participants of these forums, which enable the development of advanced semantic web capabilities in this area.     

Precautionary Money Demand in a Cash-in-Advance Economy with Capital

We use a stochastic cash-in-advance model with capital to analyze the behavior of economic agents with respect to a precautionary money demand. We show that the conditions under which agents demand more money than they actually spend in the shopping session differ according to the agent’s utility function parameter. When agents are highly risk averse, the precautionary money demand may arise under low technology shocks. The circumstances under which a nonbinding cash-in-advance constraint may appear are reversed in a model without capital. The reason of observed differences is the possibility of converting a fraction of output into capital, not only into real balances.JEL Classification: E41; E47     

Controllability in Policy Games: Policy Neutrality and the Theory of Economic Policy Revisited

Issues of policy effectiveness and policy neutrality are widespread in the economic literature. They have been raised in a number of specific contexts over the past 20 years, most notably with reference to monetary policy. However, the general conditions which ensure the non-neutrality of any or all the policy instruments available to a policymaker in a strategic context still remain to be derived. To do that, this paper provides a generalization of the classical theory of economic policy developed by Tinbergen, Theil and others to a strategic environment. Computational algorithms, so that neutrality and controllability can be tested in practice, are given. We show that many of the standard policy neutrality propositions of monetary theory and in wage bargaining models then drop out as special cases of our encompassing approach but with much simpler interpretations. JEL Classifications System: C72E52E61.     

A Class of Cross‐Layer Optimization Design for Congestion and Energy Efficiency with Compressed Sensing in Wireless Sensing Networks

In wireless sensor networks (WSNs), the congestion problem not only causes packet loss, but also leads to an increase in delays and energy consumption. The actual performance of wireless sensor networks (WSNs) can be severely influenced by the quality of the communication channel and the bit in transmission. In this paper, the distributed protocols, which attain global optimum control for signals by the compressed sensing technique and achieve fair channel allocation by the scheduling algorithm, are proposed for WSNs. We take into account the congestion problem by robust optimization with congestion ratio for two classic aspects in energy limited WSNs: minimum transmission rate and maximum transmitted information. To achieve the goal, three protocols are developed. In the first protocol, the desired control input is designed based on the compressed sensing technique. A minimal bit of signal is provided to reduce the transmission flow for the congestion model. The second protocol is resource allocation. The resources can be allocated increasingly to the channel in order to avoid more severe congestion. This can also avoid conservative reduction of resource allocation for eliminating congestion. Channel selection abides by the fair resource allocation principle. The above protocols separately are implemented through a congestion ratio at network layer, transport layer, and MAC layer. Simulation results demonstrate that the proposed algorithm effectively relieves congestion, and achieves higher throughput and lower energy consumption.     

Policy measurement for the dynamic linear model with expectations variables: A multiplier approach

To estimate the economic policy effects of per unit policy change, the conventional policy multipliers, as a measure of policy effects, can be easily calculated from the traditional dynamic econometric model without expectations variables. However, the past decade has witnessed much research and debate on the rational expectations hypothesis. In a model with expectations variables, the complexity of measuring policy effects arises not only from its dynamic properties, but also from its treatment of expectations variables.In this paper, we present a method of deriving the policy multipliers for the dynamic linear model with expectations variables and a backward recursive substitution algorithm to calculate these multipliers. The development of our methodology is basically along the traditional theory of the policy multiplier, with a substantial modification to distinguish unanticipated from anticipated policy effects.     

NNRA-CAC: NARX Neural Network-based Rate Adjustment for Congestion Avoidance and Control in Wireless Sensor Networks

A wireless sensor network (WSN) is an application area that is valuable in various fields, such as healthcare monitoring, environmental monitoring, and so on. Application areas require WSNs with high throughput and low degree of packet loss. Due to congestion in the network, the throughput of the network is affected, which imposes the need for congestion control in the network. This article proposes a method, titled NARX Neural network-based Rate Adjustment (NNRA) for avoiding and controlling congestion in the network. Initially, congestion in the network is avoided by dropping packets and the NNRA is used to control congestion in the network when congestion is present. Performance analysis is carried out in terms of throughput, delay, size of the queue, packet loss, and the level of the congestion using two setups. The results of the proposed method are compared with the existing methods to prove the effectiveness of the proposed method. The proposed method attained a maximum throughput at a rate of 0.9585 and minimum values for delay, queue size, packet loss, and the congestion level.     

A Genetic Algorithm Simulation of a Transition Economy: An Application to Insider-Privatization in Croatia

A genetic algorithm simulation is applied to a model of privatization in a transition economy. Bounded-rational agents, learning by doing in a changing economic environment, are presented as a population of artificial adaptive agents. The paper examines the comparative performances of three alternative forms of genetic algorithm – the simple GA, PGA with election and EGA with elite selection. The latter version proved to be more robust than the alternatives.     

一个数据膨胀率为1的概率公钥密码系统

在RSA公钥密码的基础上,采用时间戳和hash函数技术,并利用以Blum数为模的二次同余式中求平方根的不可计算性,设计了一个概率公钥密码系统,此密码系统的密码强度不低于RSA的密码强度和求以Blum数为模的二次同余式平方根的难度,加、解密的时间复杂度为O（k^3）,其中k为模数的长度,密码的数据膨胀率等于1,因此在数据膨胀率上,此概率公钥密码系统是最优的。     

Capital injections with negative surplus and delays: models and analysis

This work develops a new model to deal with the scenario that some companies can still run business even the surplus falls below zero temporarily. With such a scenario in mind, we allow the surplus process to continue in this negative-surplus period, during which capital injections will be ordered to assist in the stabilization of financial structure, until the financial status becomes severe enough to file bankruptcy. The capital injections will be modeled as impulse controls. By introducing the capital injections with time delays, optimal dividend payment and capital injection policies are considered. Using the dynamic programming approach, the value function obeys a quasi-variational inequality. With delays in capital injections, the company will be exposed to the risk of bankruptcy during the delay period. In addition, the optimal dividend payment and capital injection strategies should balance the expected cost of the possible capital injections and the time value of the delay periods. This gives rise to a stochastic control problem with mixed singular and delayed impulse controls. Under general assumptions, the lower capital injection barrier is determined, where bankruptcy occurs. The closed-form solution to the value function and corresponding optimal policies are obtained.