化工行业供应链的发展及对策

近20多年来,中国经济持续高速发展,多种产品总产量已居世界首位。城市化进程加快,市场需求旺盛。由于中国资源、能源人均保有量低于世界平均水平,再加上技术水平制约,相同生产过程物耗、能耗较高,造成了环境污染严重,生态状况恶化。为此,本文详细研究了我国化工行业供应链的发展及对策,具有深刻的理论意义和广泛的实际应用。     

Telecom reforms in the EU: Prices and consumers' satisfaction

The paper shows the impact of privatization and liberalization on consumers in the telecommunication sector for 15 EU countries. Policy reforms are summarized by the OECD regulatory indicators (REGREF) that consider the extent of privatization, vertical disintegration, and market entry. After controlling for other country variables, first, a test of the impact of ownership and regulatory changes on consumer prices is given. In the second step, the Eurobarometer data on consumers' satisfaction about quality and prices of the telecommunication service are considered. The analysis confirms the importance of market regulation in reducing prices but minimizes the role played by privatization per se. Overall, the findings offer only mixed evidence, and somehow contradict, the hypothesis that all the reforms work in a similar way across the EU countries.     

Naturoids: From a dream to a paradox

The human ambition to reproduce natural objects and processes has a long history, and ranges from pure dreams to actual design: from Icarus's wings to modern-day robotics and bioengineering. The concept of naturoid has been introduced in the last decade or so, for referring to man's attempts to reproduce natural phenomena. The development of naturoids may be viewed as a special class of technological activity, distinct from the general class of technology. The concept of naturoid should be useful for methodological research aimed at finding possible common rules, potentialities and constraints characterizing the human effort to reproduce natural objects.Tacitly, many designers think that the continuing improvement of a naturoid consists in its ever-growing overlap with the natural instance, and that the holy grail, as it were, is the complete reconstruction of a natural object of process, from its external appearance to its inner workings. This paper tries to show that a naturoid is always the result of a reduction of the complexity of natural objects, due to an unavoidable multiple selection strategy. Nevertheless, the reproduction process implies that naturoids take on their own new complexity, resulting in a transfiguration of the natural exemplars and their performances, leading to a true innovation explosion. As a matter of fact, the core performances of contemporary naturoids improve, but, paradoxically, the more a naturoid develops, the further away it moves from its natural counterpart. Therefore, naturoids will more and more affect our relationships with advanced technologies and with nature, but in ways quite beyond our predictive capabilities.     

Is Scale and Cost Inefficiency in the Swiss Bus Industry a Regulatory Problem? Evidence from a Frontier Cost Approach

The aim of this study is to analyze the scale and cost inefficiencies in operation for the Swiss regional bus companies. For this purpose,we have considered estimation of a stochastic and a deterministic frontier cost model for a sample of 93 bus companies in 1989. The estimates of inefficiency from the frontier models are compared and discussed within the political and regulatory setting within which the Swiss regional bus companies operate. The empirical results indicate that regulation does not seem to influence the cost efficiency significantly. Only the tariff subsidies have a negative influence on efficiency. This is an interesting result because in the current transport policy debate, the abolition of this kind of subsidy has been raised.     

人民币汇率改革的多维思考

升值幅度的确定——为什么是2％？ 2％的升值幅度的确定，实际上主要考虑的是中国的贸易顺差总体规模以及特定的经济结构调整的需要，以及企业的适应能力。2004年我国商品贸易和服务项目顺差是320亿美元，占GDP的比重不到2％，加上考虑到中国的出口弹性和进口弹性，从总量上来看，2％的升值幅度基本上可以促成实现商品贸易和服务项目的大体平衡。     

Su un problema di minimax discreto

Nell'articolo si applicano al problema di minimax discreto dei dadi truccati due condizioni di minimax locale, una necessaria, sostanzialmente già nota, e l'altra sufficiente, originale, contenute in un precedente lavoro dell'autore. Si dimostra che una distribuzione di probabilità per la qualen somme consecutive sono equiprobabili e di probabilità massima verifica la condizione necessaria e che sotto due ulteriori ipotesi, che in pratica appaiono spesso verificate, tale distribuzione verifica altresì la condizione sufficiente di minimax locale. Si deduce quindi un risultato di Clemens.     

How good can heuristic-based forecasts be? A comparative performance of econometric and heuristic models for UK and US asset returns

This paper systematically investigates the sources of differential out-of-sample predictive accuracy of heuristic frameworks based on internet search frequencies and a large set of econometric models. The volume of internet searches helps gauge the degree of investors’ time-varying interest in specific assets. We use a wide range of state-of-the-art models, both of linear and nonlinear type (regime-switching predictive regressions, threshold autoregressive, smooth transition autoregressive), extended to capture conditional heteroskedasticity through GARCH models. The predictor variables investigated are those typical of the literature featuring a range of macroeconomic and market leading indicators. Our out-of-sample forecasting exercises are conducted with reference to US, UK, French and German data, both stocks and bonds, and for 1- and 12-months-ahead horizons. We employ several forecast performance metrics and predictive accuracy tests. Internet-search-based models are found to perform better than the average of all of the alternative models. For several country-asset-horizon combinations, particularly for UK bond returns, our heuristic models compare favourably with sophisticated econometric methods. The heuristic models are also shown to perform well in forecasting realized volatility. The baseline results are supported by several extensions and robustness checks, such as using alternative search keywords, controlling for Fama–French and Cochrane–Piazzesi factors, and implementing heuristic-based trading strategies.     

Self-reflexive networks: Theory · topology · applications

We present a new type of Artificial Neural Networks: the Self-Reflexive Networks. We utter the theoretical presuppositions; their dynamics is analogous to the one ascribed to autopoietic systems: self-referentiality, unsupervised learning and unintentionally cooperative and contractual activities of their own units. We also hypothesize a new concept of perception. We present the basic equations of Self-Reflexive Networks, new concepts as the one of dynamic target, of Re-entry with dedicated and fixed connections, of Meta-Units. Therefore, we experiment a specific type of Self-Reflexive Networks, the Monodedicated, within the interpretation of a toy-DB and we have hinted at other already made experimentations, experimentations in process and planned experimentations. From the applicative work that we present a few specifics and novelties of this type of Neural Networks emerge:

1. the capability of answering to complex, strange, wrong or not precise questions, through the same algorithms through which the learning phase took place.
2. the capability of spontaneously transforming their own learning inaccuracy in analogic capability and original self-organization capability.
3. the capability of spontaneously integrate the models that it experienced in different moments in an achronical hyper-model.
4. the capability of behaving as it had explored a decisions graph of large dimensions, both deeply and in extension. With the consequence of behaving as an Addressing Memory forself-dynamic Contents.
5. the capability of always learning, rapidly and anyway, besides the complexity of the learning patterns.
6. the capability of answering simultaneously from different points of view, behaving, in this case, as a network that builds more similarity models for each vector-stimulus that it receives.
7. the capability of adjusting in a biunivocal way, each question to the consulting DB and each DB to the question that are submitted. The consequence of this fact is the continuous creation of new answering models.
8. the capability of building during the learning phase, a weights matrix that provides a subconceptual representation of the bi-directional relations between each couple of input variables.
9. the capability, through the Metaunits, to integrate in a unitary typology, nodes with different saturation speed and, therefore, with different memory: in fact, while the SR units are short memory nodes, since each new stumulus zeros the previous stimulus, the Metaunits memorize the SR different stimulus during time, functioning as an average length memory. This fact should confirm that the avarage length memory is of a different level from the immediate memory and that it is based only uponrelation among perceptive stimulus which are distributed in parallel and in sequence. In this context the weights matrix constitute the SR long term memory. And in this sense it will be opportune to think at a methodic through which the Metaunits can influence during time, the same weights matrix. In any case, in the SR there areservice nodes orfilter nodes andlearning nodes as if they were weights (the Metaunits).

     

Venture Capital Investments in Europe and Portfolio Firms' Economic Performance: Independent Versus Corporate Investors

Using a new European Commission‐sponsored longitudinal dataset—the VICO dataset—we assess the impact of independent (IVC) and corporate venture capital (CVC) investments on the economic performance of European high‐tech entrepreneurial firms during the period 1992–2010. After controlling for potential sources of endogeneity and selection bias, our results indicate that both IVC and CVC investments boost portfolio firms' economic performance. These effects are mostly due to an increase in real sales value. Moreover, the dynamics of the impact of VC investments on firms’ overall economic performance and its components—real sales value, real fixed assets, and real labor costs—differs depending on the type of investor. Finally, we do not detect any impact related to the syndication of investments by both IVC and CVC investors.     

MAXIMUM LIKELIHOOD ESTIMATION OF FACTOR MODELS ON DATASETS WITH ARBITRARY PATTERN OF MISSING DATA

In this paper we modify the expectation maximization algorithm in order to estimate the parameters of the dynamic factor model on a dataset with an arbitrary pattern of missing data. We also extend the model to the case with a serially correlated idiosyncratic component. The framework allows us to handle efficiently and in an automatic manner sets of indicators characterized by different publication delays, frequencies and sample lengths. This can be relevant, for example, for young economies for which many indicators have been compiled only recently. We evaluate the methodology in a Monte Carlo experiment and we apply it to nowcasting of the euro area gross domestic product. Copyright © 2012 John Wiley & Sons, Ltd.