Noisy chaotic dynamics in commodity markets

The nonlinear testing and modeling of economic and financial time series has increased substantially in recent years, enabling us to better understand market and price behavior, risk and the formation of expectations. Such tests have also been applied to commodity market behavior, providing evidence of heteroskedasticity, chaos, long memory, cyclicity, etc. The present evaluation of futures price behavior confirms that the resulting price movements can be random, suggesting noisy chaotic behavior. Prices could thus follow a mean process that is dynamic chaotic, coupled with a variance that follows a GARCH process. Our conclusion is that models of this type could be constructed to assist in forecasting prices in the short run but not over long run time periods.First version received: June 2001/Final version received: March 2003     

A Permanent Income Model of Public Consumption

This paper tests the permanent income hypothesis (PIH) for public consumption. Unlike private agents, a government is a representative national, infinitely-lived agent that usually faces no liquidity constraints. Thus, the expectation is that the PIH restrictions should not be rejected for public consumption. However, using U.S. data, the paper is unable to find evidence supporting the permanent income model of public consumption. Public consumption is found to be sensitive to lagged public income and too smooth relative to permanent public income. The results therefore cast doubt on the characterization of the public sector as a social welfare optimizing agent.     

Parallel Neutrality

This paper develops the notion of parallel-neutral technical change for inputs and outputs. It is shown that parallel-neutral technical change generalizes existing radial notions of neutral technical change. A taxonomy of the structural consequences of parallel-neutral technical change is developed.     

Bargaining under Uncertainty and the Monotone Path Solutions

Uncertainty with respect to the feasible set of utility vectors is introduced in an axiomatic bargaining model. Given a criterion for nonprobabilistic decision-making under uncertainty, a natural efficiency requirement can be imposed on a bargaining solution. Using the maximin ordering, thestrictly monotone pathsolutions (generalizations of theegalitariansolution) to the bargaining problem are characterized as the only continuous solutions that satisfy this efficiency axiom. If the maximin criterion is replaced by the maximax ranking or a strict convex combination of the maximin and the maximax criterion, imposing our efficiency axiom and continuity leads to thedictatorialsolutions.Journal of Economic LiteratureClassification Number: C78.     

Aggregation of Directional Distance Functions and Industrial Efficiency

Three main objectives are pursued in this paper. First, we intend to analyze the aggregation problem of directional distance functions from a constructive viewpoint. We provide necessary and sufficient conditions concerning the structural properties of the production technology and of the nature of groups of firms. Indeed, exact additive aggregation holds for a linear technology and for a direction solely defined in the output space. Second, since these conditions are somewhat restrictive, we are interested in providing a measure for the aggregation bias through the relationship between industrial and structural technical efficiency. Finally, we show that this aggregation bias is a lower bound for industrial allocative efficiency.     

Continuous choice functions and the strong axiom of revealed preference

Summary In this note, it is shown that a result due to Uzawa showing that the weak axiom of revealed preference together with a regularity condition implies the strong axiom of revealed preference can be derived from the regularity conditionalone, if the choice function is continuous in prices and in income. The observation that the weak axiom of revealed preference is not needed suggests that this regularity condition is remarkably strong. The main result of the paper is quite general in the sense that the only additional assumption on the choice function is that the whole budget be spent.I thank Charles Blackorby for his comments on an earlier version.     

Karoushi: Stress-death and the meaning of work

The present article is concerned with some of the human factors involved when overtime and overwork become part of the regular and accepted pattern of work, with sometimes tragic results. While the economic miracle of Japan can be much admired, it has not been without human cost. Only recently, national and global attention is being focused on a new and deadly phenomenon in Japan:Karoushi, which the Japanese define as death from overwork, and which I choose to re-define as stress-death related to feelings of helplessness.It is my tentative hypothesis thatkaroushi is not directly caused by overwork, as popularly assumed. Rather, I believe that overwork is only one factor, and that stress-death is actually caused by the cumulative, long-range effects of working in a situation where one feels trapped and powerless to effect any change for the better, which in turn leads to attitudes of hopelessness — attitudes which are exacerbated, rather than ameliorated, by environmental and managerial factors.Dr. Walter Tubbs received his Ph.D. in Neuropsychology and Philosophy after doing work at Stanford and Drew Universities. After involvement in brain research at Stanford, he practiced stress-management counseling and biofeedback training at Loma Linda University, and taught for 13 years at the University of Redlands in California. He has been in Japan for 11 years as a Senior Researcher.     

Patent-based inventor profiles as a basis for human resource decisions in research and development

Profiles of inventors' technological competence are a valuable source of information for decision-making in research and development (R&D) management, e.g. concerning inventor assessment, human resource development and R&D team-building. In the following exposition, a new method of inventor profiling will be put forward, which is based in particular on semantic patent analysis and multidimensional scaling. First, in the course of semantic patent analysis, specialized software, equipped with a natural language processor, reads the patent text transferring the contents into a subject–action–object–format (SAO). The extracted SAO structures are then used to create similarity matrices for patents or patent sets, respectively, according to a specific similarity value. Subsequently, an inventor competence map can be produced by means of multidimensional scaling.
The benefits of this method for R&D-related issues in human resource management will be illustrated by the example of a German mechanical engineering company. Two distinct types of profiles were generated and tested: (i) the profile of a single key inventor and (ii) a profile of key inventor sets. The single key inventor profile gives information on the range of competence, i.e. the homogeneity or heterogeneity of a certain inventor's competences, providing far more detailed insights than resorting to bibliographic data like international patent classification (IPC) classes or citations, whereas the latter kind of profile establishes the position of a certain key inventor in relation to others, helping to highlight specific groups of inventors and their domains. These results are clearly apt to support human resource management.     

Evaluating the risk of patent infringement by means of semantic patent analysis: the case of DNA chips

In this paper, we are going to present a method for detecting the risks of patent infringement by evaluating similarities between patent documents on the basis of semantic patent analysis. This approach enables the user to visualize similarities in the contents on a semantic patent map by means of multi‐dimensional scaling. The effectiveness of the semantic patent map has already been demonstrated by Dressler (2006) with regard to patents of seal technology, in which documents are commonly kept short and the extracted contents are concise. This paper will open out to the field of biotechnology, where patents can easily comprise several hundreds of pages. The method presented here conveys an interdisciplinary approach and combines computer‐aided natural language processing with domain‐specific expertise of biochemical processes. This is illustrated by an authentic case of infringement involving two manufacturers of DNA chips. Our experiment will show how the infringement case is visualized on a patent map based on semantic patent analysis. This experiment can be compared with the search for a needle in a haystack, the two competitive patents representing significantly conflicting ‘needles.’ From an approximate number of 4,000 patents in the current US Class 435/6, a set of patents was selected that included the ‘needles’ mentioned. This paper will point out how such mutual interference can be detected by way of semantic patent analysis, and what advice may be given to R&D managers who are faced with the risk of patent infringement.